The document discusses power quality monitoring and its importance for sustainable energy systems like solar power in India. It provides context on increased sensitivity of modern equipment to power quality issues and defines different types of steady state variations and events that impact power quality. Monitoring objectives include proactive and reactive approaches to characterize system performance and identify specific problems. The development of an intelligent power quality monitoring system using LabVIEW and sensors is described to efficiently monitor power quality in sustainable energy systems.
This document summarizes a PhD seminar presentation on microgrids and their control. It defines a microgrid as a group of distributed energy resources and loads that can disconnect from the traditional grid to operate autonomously. It describes the basic architecture of microgrids including sources, storage, loads, and power electronics. It discusses different modes of microgrid operation such as grid-connected, island, and various control strategies. Finally, it reviews several relevant research papers on topics like microgrid control optimization, voltage and current harmonics, and black start capabilities.
This document discusses power quality monitoring. It defines power quality as the properties of the power supply delivered to users. Power quality can be affected by various steady state variations and events that cause deviations from the ideal voltage waveform. The document describes different types of power quality disturbances and how automatic classifiers are used to classify disturbances. It discusses power quality monitoring objectives and the types of commercially available power quality monitors used to identify and analyze power quality problems.
This document discusses the integration of smart grid technology with renewable energy sources for energy demand management. It provides motivation for this integration by highlighting issues with India's traditional electric grid like pollution from non-renewable plants that causes health hazards. The solution proposed is a smart grid that reduces pollution and enables demand management through technologies like microgrids. It then summarizes a case study in Puducherry, India where a smart grid pilot project was implemented combining distributed renewable generation, smart homes, and smart meters to automatically manage energy demand during peak hours.
A flexible alternating current transmission system (FACTS) is a system composed of static equipment used for the AC transmission of electrical energy. It is meant to enhance controllability and increase power transfer capability of the network. It is generally a power electronics-based system.
In conventional AC transmission system, the ability to transfer AC power is limited by several factors like thermal limits, transient stability limit, voltage limit, short circuit current limit etc. These limits define the maximum electric power which can be efficiently transmitted through the transmission line without causing any damage to the electrical equipments and the transmission lines. This is normally achieved by bringing changes in the power system layout. However this is not feasible and another way of achieving maximum power transfer capability without any changes in the power system layout. Also with the introduction of variable impedance devices like capacitors and inductors, whole of the energy or power from the source is not transferred to the load, but a part is stored in these devices as reactive power and returned back to the source. Thus the actual amount of power transferred to the load or the active power is always less than the apparent power or the net power. For ideal transmission the active power should be equal to the apparent power. In other words, the power factor (the ratio of active power to apparent power) should be unity. This is where the role of Flexible AC transmission System comes.
This document discusses power quality issues such as voltage sags, interruptions, spikes, swells, and harmonics. It explains the causes and consequences of each issue. Solutions discussed include improving the electric grid, using distributed energy resources like generators and energy storage, following standards, installing enhanced interface devices, and making equipment less sensitive. The key is preventing power quality problems through various measures to avoid losses.
POWER SYSTEM PLANNING AND DESIGN. DESIGN OF EHV TRANSMISSION LINES & BUNDLED ...
This document discusses the design of extra high voltage transmission lines and bundled conductors in EHV lines. It outlines the advantages of EHV lines such as reduced transmission losses and material requirements. However, it also notes disadvantages like increased corona losses and insulation needs. Key design considerations for EHV lines include the choice of operating voltage, grounding method, conductor selection, and insulator selection. For lines above 400kV, bundled conductors are used and the document discusses formulas for calculating the inductance, capacitance, surge impedance, and surge impedance loading to determine bundling requirements.
Renewable Energy Sources are being used in Off-Grid mode. By integrating all these sources to a common point energy efficiency can be improved and frequent dynamic faults can be avoided. This approach needs to implement smart grid and technologies.
with the help of web based power quality monitoring system we can control and manage the data flow of electrical quantity and control the improve the quality of the power system in grid
A power quality monitoring system gathers and analyzes electricity measurement data to provide useful information. It allows plants to perform energy management, preventive maintenance, quality control, and save money. Power quality monitoring equipment includes digital fault recorders, smart relays, voltage recorders, in-plant power monitors, and special-purpose power quality equipment. These devices monitor voltage, current, and other measurements to detect issues like harmonics, sags, disturbances and optimize power quality and performance.
Unit I: Introduction to Protection System:
Introduction to protection system and its elements, functions of protective relaying, protective zones, primary and backup protection, desirable qualities of protective relaying, basic terminology.
Relays:
Electromagnetic, attracted and induction type relays, thermal relay, gas actuated relay, design considerations of electromagnetic relay.
Unit-II: Relay Application and Characteristics:
Amplitude and phase comparators, over current relays, directional relays, distance relays, differential relay.
Static Relays: Comparison with electromagnetic relay, classification and their description, over current relays, directional relay, distance relays, differential relay.
Unit-III Protection of Transmission Line:
Over current protection, distance protection, pilot wire protection, carrier current protection, protection of bus, auto re-closing,
Unit-IV: Circuit Breaking:
Properties of arc, arc extinction theories, re-striking voltage transient, current chopping, resistance switching, capacitive current interruption, short line interruption, circuit breaker ratings.
Testing Of Circuit Breaker: Classification, testing station and equipments, testing procedure, direct and indirect testing.
Unit-V Apparatus Protection:
Protection of Transformer, generator and motor.
Circuit Breaker: Operating modes, selection of circuit breakers, constructional features and operation of Bulk Oil, Minimum Oil, Air Blast, SF6, Vacuum and d. c. circuit breakers.
This presentation provides an overview of power quality, including definitions of power quality, common power quality disturbances like sags, swells, harmonics and interruptions. It discusses the increased sensitivity of modern electronic equipment to power quality issues. Real-time power quality monitoring systems are described that can identify issues, locate their sources, and help utilities and customers mitigate problems to reduce costs and equipment damage. The benefits of power quality monitoring include improved reliability, preventative maintenance, and identification of sensitive equipment needing protection.
The document discusses smart grids, providing definitions and comparisons to traditional grids. It outlines key features of smart grids like reliability, efficiency, sustainability, and flexibility. Smart meters are defined as measuring electricity use and allowing two-way communication between utilities and customers. Security is an important aspect to protect smart grid data and ensure integrity, availability, and confidentiality. The document reviews recent literature on smart grid techniques and applications in areas like home energy management, electric vehicle charging, and grid control systems.
This document provides an overview of wind turbine systems that use power electronics converters. It discusses how wind energy is converted into electrical energy and fed into the electrical grid. Power electronics converters are necessary to regulate voltage and frequency from the generator to meet grid requirements. Common converter configurations for wind turbines include the doubly fed induction generator with a partial scale back-to-back converter and permanent magnet synchronous generators with a full-scale back-to-back converter. Power electronics improve system stability and power quality by enabling control of active and reactive power flow between the generator and grid.
Power quality refers to maintaining a steady supply of electric power that operates equipment properly without damage or stress. Issues like voltage fluctuations, frequency variations, harmonic distortions, and low power factor can reduce efficiency and increase energy consumption and equipment damage. Common causes of power quality issues are weather events, falling trees, vehicle accidents, and construction accidents disturbing overhead power lines.
EHV (extra high voltage) AC transmission refers to equipment designed for voltages greater than 345 kV. Higher transmission voltages increase efficiency by reducing transmission losses and current, decrease infrastructure costs, and increase transmission capacity. However, they also present safety and interference risks. New technologies like FACTS (flexible AC transmission systems) help maximize the benefits of EHV transmission by enabling voltage control and power flow management. There is growing support for expanding national EHV transmission grids to facilitate large-scale renewable energy integration and inter-regional power sharing.
This document discusses maximum power point tracking (MPPT) techniques for solar panels. It begins with an introduction to MPPT and its objective to increase solar panel efficiency by extracting more power. Several MPPT techniques are described, including perturb and observe, incremental conductance method. The document provides mathematical models and diagrams to illustrate solar cell characteristics and how MPPT techniques work. It also discusses hardware implementation and the advantages of MPPT, concluding that incremental conductance performs best under varying conditions.
This document summarizes a PhD seminar presentation on microgrids and their control. It defines a microgrid as a group of distributed energy resources and loads that can disconnect from the traditional grid to operate autonomously. It describes the basic architecture of microgrids including sources, storage, loads, and power electronics. It discusses different modes of microgrid operation such as grid-connected, island, and various control strategies. Finally, it reviews several relevant research papers on topics like microgrid control optimization, voltage and current harmonics, and black start capabilities.
This document discusses power quality monitoring. It defines power quality as the properties of the power supply delivered to users. Power quality can be affected by various steady state variations and events that cause deviations from the ideal voltage waveform. The document describes different types of power quality disturbances and how automatic classifiers are used to classify disturbances. It discusses power quality monitoring objectives and the types of commercially available power quality monitors used to identify and analyze power quality problems.
Integration of smart grid with renewable energySAGAR D
This document discusses the integration of smart grid technology with renewable energy sources for energy demand management. It provides motivation for this integration by highlighting issues with India's traditional electric grid like pollution from non-renewable plants that causes health hazards. The solution proposed is a smart grid that reduces pollution and enables demand management through technologies like microgrids. It then summarizes a case study in Puducherry, India where a smart grid pilot project was implemented combining distributed renewable generation, smart homes, and smart meters to automatically manage energy demand during peak hours.
A flexible alternating current transmission system (FACTS) is a system composed of static equipment used for the AC transmission of electrical energy. It is meant to enhance controllability and increase power transfer capability of the network. It is generally a power electronics-based system.
In conventional AC transmission system, the ability to transfer AC power is limited by several factors like thermal limits, transient stability limit, voltage limit, short circuit current limit etc. These limits define the maximum electric power which can be efficiently transmitted through the transmission line without causing any damage to the electrical equipments and the transmission lines. This is normally achieved by bringing changes in the power system layout. However this is not feasible and another way of achieving maximum power transfer capability without any changes in the power system layout. Also with the introduction of variable impedance devices like capacitors and inductors, whole of the energy or power from the source is not transferred to the load, but a part is stored in these devices as reactive power and returned back to the source. Thus the actual amount of power transferred to the load or the active power is always less than the apparent power or the net power. For ideal transmission the active power should be equal to the apparent power. In other words, the power factor (the ratio of active power to apparent power) should be unity. This is where the role of Flexible AC transmission System comes.
This document discusses power quality issues such as voltage sags, interruptions, spikes, swells, and harmonics. It explains the causes and consequences of each issue. Solutions discussed include improving the electric grid, using distributed energy resources like generators and energy storage, following standards, installing enhanced interface devices, and making equipment less sensitive. The key is preventing power quality problems through various measures to avoid losses.
POWER SYSTEM PLANNING AND DESIGN. DESIGN OF EHV TRANSMISSION LINES & BUNDLED ...Jobin Abraham
This document discusses the design of extra high voltage transmission lines and bundled conductors in EHV lines. It outlines the advantages of EHV lines such as reduced transmission losses and material requirements. However, it also notes disadvantages like increased corona losses and insulation needs. Key design considerations for EHV lines include the choice of operating voltage, grounding method, conductor selection, and insulator selection. For lines above 400kV, bundled conductors are used and the document discusses formulas for calculating the inductance, capacitance, surge impedance, and surge impedance loading to determine bundling requirements.
Renewable Energy Sources are being used in Off-Grid mode. By integrating all these sources to a common point energy efficiency can be improved and frequent dynamic faults can be avoided. This approach needs to implement smart grid and technologies.
with the help of web based power quality monitoring system we can control and manage the data flow of electrical quantity and control the improve the quality of the power system in grid
A power quality monitoring system gathers and analyzes electricity measurement data to provide useful information. It allows plants to perform energy management, preventive maintenance, quality control, and save money. Power quality monitoring equipment includes digital fault recorders, smart relays, voltage recorders, in-plant power monitors, and special-purpose power quality equipment. These devices monitor voltage, current, and other measurements to detect issues like harmonics, sags, disturbances and optimize power quality and performance.
Unit I: Introduction to Protection System:
Introduction to protection system and its elements, functions of protective relaying, protective zones, primary and backup protection, desirable qualities of protective relaying, basic terminology.
Relays:
Electromagnetic, attracted and induction type relays, thermal relay, gas actuated relay, design considerations of electromagnetic relay.
Unit-II: Relay Application and Characteristics:
Amplitude and phase comparators, over current relays, directional relays, distance relays, differential relay.
Static Relays: Comparison with electromagnetic relay, classification and their description, over current relays, directional relay, distance relays, differential relay.
Unit-III Protection of Transmission Line:
Over current protection, distance protection, pilot wire protection, carrier current protection, protection of bus, auto re-closing,
Unit-IV: Circuit Breaking:
Properties of arc, arc extinction theories, re-striking voltage transient, current chopping, resistance switching, capacitive current interruption, short line interruption, circuit breaker ratings.
Testing Of Circuit Breaker: Classification, testing station and equipments, testing procedure, direct and indirect testing.
Unit-V Apparatus Protection:
Protection of Transformer, generator and motor.
Circuit Breaker: Operating modes, selection of circuit breakers, constructional features and operation of Bulk Oil, Minimum Oil, Air Blast, SF6, Vacuum and d. c. circuit breakers.
This presentation provides an overview of power quality, including definitions of power quality, common power quality disturbances like sags, swells, harmonics and interruptions. It discusses the increased sensitivity of modern electronic equipment to power quality issues. Real-time power quality monitoring systems are described that can identify issues, locate their sources, and help utilities and customers mitigate problems to reduce costs and equipment damage. The benefits of power quality monitoring include improved reliability, preventative maintenance, and identification of sensitive equipment needing protection.
The document discusses smart grids, providing definitions and comparisons to traditional grids. It outlines key features of smart grids like reliability, efficiency, sustainability, and flexibility. Smart meters are defined as measuring electricity use and allowing two-way communication between utilities and customers. Security is an important aspect to protect smart grid data and ensure integrity, availability, and confidentiality. The document reviews recent literature on smart grid techniques and applications in areas like home energy management, electric vehicle charging, and grid control systems.
This document provides an overview of wind turbine systems that use power electronics converters. It discusses how wind energy is converted into electrical energy and fed into the electrical grid. Power electronics converters are necessary to regulate voltage and frequency from the generator to meet grid requirements. Common converter configurations for wind turbines include the doubly fed induction generator with a partial scale back-to-back converter and permanent magnet synchronous generators with a full-scale back-to-back converter. Power electronics improve system stability and power quality by enabling control of active and reactive power flow between the generator and grid.
The document discusses Automatic Meter Reading (AMR) systems. It describes AMR as the remote collection of meter data from customer premises via communication links. The presentation covers how AMR systems work using components like the encoder-receiver-transmitter, meter interface unit, data concentrator unit and host central station. Benefits of AMR include reduced costs, improved customer service, and better detection of leaks or theft. The document provides an overview of AMR system architecture and its advantages over conventional meter reading.
Modeling of a single phase Grid-connected PV system by using Matlab/SimulinkSai Divvela
This document presents a model of a single-phase grid-connected photovoltaic (PV) system developed in MATLAB/Simulink. The main components are a PV array, DC-DC boost converter, PWM inverter, and MPPT controller. The objective is to study the performance of the system. It describes each component, including how the PV array converts solar energy to electricity, the DC-DC converter steps up the voltage, the PWM inverter converts DC to AC, and the MPPT controller tracks the maximum power point. Simulation results show that increasing solar irradiance increases the PV array output power and power quality supplied to the grid.
This document discusses power quality and defines it as any deviation from the normal sinusoidal voltage or current waveform. It covers various power quality issues like voltage sags, swells, fluctuations, harmonics, interruptions and more. It explains the causes and impacts of different power quality problems. The document also discusses classification of issues, measurement and evaluation of power quality as well as relevant standards from organizations like IEEE.
The quality of power supply is very important in any power network particularly to electricity consumers. Power quality encompasses availability of supply, frequency and voltage magnitude as well as waveform characteristics of the power supply.
IRJET-Review on Power Quality Enhancement in weak Power Grids by Integration ...IRJET Journal
Prathmesh Mayekar, Mahesh Wagh, Nilkanth Shinde "Review on Power Quality Enhancement in weak Power Grids by Integration of Renewable Energy Technologies", International Research Journal of Engineering and Technology (IRJET), Volume2,issue-01 April 2015.e-ISSN:2395-0056, p-ISSN:2395-0072. www.irjet.net
Abstract
During Last decade power quality problems has become more complex at all level of power system. With the increased use of sophisticated electronics, high efficiency variable speed drive, power electronic controllers and also more & more non-linear loads, Power Quality has become an increasing concern to utilities and customers. The modern sensitive, Non-linear and sophisticated load affects the power quality. This paper deals with the issues of low power quality in weak power grids. Initially the various power quality issues are discussed with their definition or occurrence and then finally the solution to mitigate this power quality issues are discussed. The innovative solutions like integration of renewable energy systems along with energy storage to enhance power quality by interfacing with custom power devices are explained in detail. Nearly all sorts of solution for mitigating power quality issue require some sort of DC source for providing active power, which can be supplied by renewable energy source. Also the various energy storage systems are studied.
IRJET- A Comparative Study of Various Filters for Power Quality ImprovementIRJET Journal
This document discusses various filters that can be used to improve power quality by reducing harmonics and correcting power factor. It describes passive filters, shunt active power filters, and series active power filters. Shunt active power filters inject harmonic currents to cancel out load harmonics, while series active power filters generate compensating voltages. Both types of active filters require control schemes to generate the proper compensating signals. Passive filters use tuned filter branches to sink harmonic currents or block harmonic voltages. The document evaluates the compensation characteristics and control methods of different filter topologies to mitigate power quality issues like harmonics and reactive power.
Power quality issues arise from disturbances in the electric power supply that can negatively impact equipment. Common issues include voltage sags, swells, interruptions, harmonics, and spikes. Around 80% of problems originate from within industrial facilities due to large loads or improper wiring, while 20% come from external utility issues like weather events. Poor power quality can increase energy costs and cause equipment failures. Monitoring power quality helps identify disturbances and their sources to improve reliability and reduce costs. Various devices like filters, regulators, and compensators can help mitigate different power quality issues. Maintaining high power quality supports the economic operation of power systems and equipment.
Power Quality Improvement by UPQC based on Voltage Source ConvertersIJRST Journal
In modern power system consists of wide range of electrical, electronic and power electronic equipment in commercial and industrial applications. Since most of the electronic equipment’s are nonlinear in nature these will induce harmonics in the system, which affect the sensitive loads to be fed from the system. These problems are partially solved with the help of LC passive filters. However, this kind of filter cannot solve random variation in the load current wave form and voltage wave form. Active filters can resolve this problem. However, the cost of active filters is high. They are difficult to implement in large scale. Additionally, they also present lower efficiency than shunt passive filters. One of the many solutions is the use of a combined system of shunt and active series filters like Unified Power Quality Conditioner (UPQC) which aims at achieving a low cost under highly effective control. The UPQC device combines a shunt active filter together with a series active filter in a back-to-back configuration, to simultaneously compensate the supply voltage and the load current or to mitigate any type of voltage and current fluctuations and power factor correction in a power distribution network, such that improved power quality can be made available at the point of common coupling. The control strategies are modeled using MATLAB/SIMULINK. The performance is also observed under influence of utility side disturbances such as harmonics and voltage sags. The simulation results are compared without and with UPQC for the verification of results.
A Voltage Controlled Dstatcom for Power Quality Improvementiosrjce
Due to increasing complexity in the power system, voltage sag is becoming one of the most significant
power quality problems. Voltage sag is a short reduction voltage from nominal voltage, occurs in a short time.
If the voltage sags exceed two to three cycles, then manufacturing systems making use of sensitive electronic
equipments are likely to be affected leading to major problems. It ultimately leads to wastage of resources (both
material and human) as well as financial losses. This is possible only by ensuring that uninterrupted flow of
power is maintained at proper voltage levels. This project tends look at the solving the sag problems by using
custom power devices such as Distribution Static compensator (D-STATCOM).Proposed scheme follows a new
algorithm to generate reference voltage for a distribution static compensator (DSTATCOM) operating in
voltage-control mode. The proposed scheme ensures that unity power factor (UPF) is achieved at the load
terminal during nominal operation, which is not possible in the traditional method. Also, the compensator
injects lower currents therefore, reduces losses in the feeder and voltage-source inverter. Further, a saving in
the rating of DSTATCOM is achieved which increases its capacity to mitigate voltage sag. Nearly UPF is
maintained, while regulating voltage at the load terminal, during load change. The state-space model of
DSTATCOM is incorporated with the deadbeat predictive controller for fast load voltage regulation during
voltage disturbances. With these features, this scheme allows DSTATCOM to tackle power-quality issues by
providing power factor correction, harmonic elimination, load balancing, and voltage regulation based on the
load requirement.
This document presents a study on using a Distribution Static Compensator (DSTATCOM) to improve power quality issues like voltage sags and swells. It begins with an introduction to power quality problems such as voltage sags, swells, harmonics and transients. It then discusses different custom power devices that can be used as solutions, focusing on DSTATCOM. The document presents the configuration, modelling and control of a DSTATCOM. It proposes a control scheme for DSTATCOM and presents simulation results demonstrating its ability to regulate voltage during sags and improve power factor. The conclusion states that the proposed DSTATCOM scheme can effectively mitigate various power quality issues related to voltage and current.
This document discusses power quality and issues that can arise such as voltage variations, frequency variations, and waveform distortions. It defines key power quality terms like sags, swells, flicker, harmonics, and describes how loads and generation sources can impact power quality. Active power filters are presented as a solution to power quality problems in electric rail systems by compensating for unbalance, harmonic distortion, and low power factor. Compression algorithms are also discussed to efficiently store and analyze large power quality data sets.
Electrical power is an intrinsic and essential part of modern life. It is generated and delivered across miles to power homes and businesses,operate a wide range of equipment and devices. We take power for granted, rarely bothering to ask “how good is the quality ofthe power I am using?”; “am I using it correctly?”; “is my equipment compatible to function with the power provided?” etc.
This document discusses a study analyzing and simulating a Dynamic Voltage Restorer (DVR) to compensate for power quality issues like voltage sags and swells. A DVR is a custom power device that injects voltage into the distribution system to regulate the load voltage. It monitors the load voltage and injects or absorbs any imbalance to maintain the load voltage within tolerance limits. The document outlines different power quality problems caused by faults and equipment, and introduces DVRs and other custom power devices as effective solutions to mitigate issues like voltage sags and harmonics.
This document discusses the use of multiresolution signal decomposition (MSD) and wavelet transform (WT) techniques to detect and localize power quality disturbances. It presents a case study analyzing power system switching transients caused by capacitor switching. The original disturbance signal is decomposed into smoothed and detailed signals at multiple scales using MSD and WT. The detailed signals contain the high frequency components and clearly indicate the occurrence of disturbances like the voltage step change from capacitor energizing. The proposed MSD and WT approach is effective for robust detection and localization of power quality issues from switching events.
Voltage Flicker Analysis and its Mitigation by STATCOM for Power Quality Impr...IJMTST Journal
Voltage flicker is considered as one of the most severe power quality problems (especially in loads like electrical arc furnaces) and much attention has been paid to it lately. The reason for this disturbance is mainly due to the large nonlinear loads such as electric arc furnaces. Due to the latest achievements in the semiconductors industry and consequently the emergence of the compensators based on voltage source converters, FACTS devices have been gradually noticed to be used for voltage flicker compensation. This paper covers the contrasting approaches; dealing with the voltage flicker mitigation in three stages and assessing the related results in details. Initially, the voltage flicker mitigation, using FCTCR (Fixed Capacitor Thyristor Controlled Reactor), was simulated. Secondly, the compensation for the Static Synchronous Compensator (STATCOM) has been performed. The voltage flicker compensation by 8– pulse as well as 12 – pulse static synchronous compensator (STATCOM) has been performed. This paper deals with the voltage flicker mitigation and reduction in total harmonic distortion (THD) and compared the results in detail. The obtained results show that STATCOM is very efficient and effective for the compensation and mitigation of voltage flicker and harmonics all the simulation results have been performed on the MATLAB Software.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
1) The document discusses various power quality problems faced in power systems such as voltage sags, interruptions, flicker, surges, spikes, and harmonics.
2) It describes different types of active power filters that can be used to solve power quality issues, including shunt active filters that inject compensating current, and series active filters that inject compensating voltage.
3) The unified power quality conditioner is introduced, which uses both series and shunt active filters to improve both voltage and current quality by controlling series injected voltage and shunt injected current.
Control of Dvr with Battery Energy Storage System Using Srf TheoryIJERA Editor
One of the best solutions to improve power quality is the dynamic voltage restorer (DVR). DVR is a kind of
custom power devices that can inject active/reactive power to the power grids. This can protect loads from
disturbances such as sag and swell. Usually DVR installed between sensitive loads feeder and source in
distribution system. Its features include lower cost, smaller size, and its fast dynamic response to the
disturbance. In this project SRF technique is used for conversion of voltage from rotating vectors to the
stationary frame. SRF technique is also referred as park’s transformation. In this the reference load voltage is
estimated using the unit vectors. The real power exchanged at the DVR output ac terminal is provided by the
DVR input dc terminal by an external energy source or energy storage system. In this project three phase
parallel or series load may be used along with SRF technique to compensate voltage sag and voltage swell. And
also wind generator is also used as a load. This project presents the simulation of DVR system using
MATLAB/SIMULINK.
This document summarizes a paper about different types of power problems. It begins by introducing the topic and defining key power quality issues like transients, interruptions, sag/swell, and waveform distortion. It then describes the causes and effects of different types of transients, including impulsive transients from lightning and oscillatory transients from switching operations. Standards for defining and measuring power problems are also discussed. The document provides examples and diagrams to illustrate power quality events. In summary, it provides an overview of common power problems, their characteristics, causes, and potential impacts.
A Novel Multi Level Converter Unified Power – Quality (MC-UPQC) Conditioning ...IRJET Journal
This document discusses a novel multi-level converter unified power quality conditioning system (MC-UPQC) capable of simultaneously compensating for voltage and current in multi-bus/multi-feeder systems. The proposed MC-UPQC topology includes one shunt voltage-source converter and two or more series VSCs, allowing power to be transferred between feeders to compensate for sags, swells, and interruptions. Simulation results show the MC-UPQC can significantly reduce power losses, mitigate under voltages, and enhance voltage stability in distribution networks compared to other designs. The MC-UPQC provides a more efficient solution for under voltage mitigation in multi-feeder systems.
MITIGATING ELECTRICAL DISTURBANCES WITH HYBRID DISTRIBUTION TRANSFORMERijscmcj
Hybrid transformers (HT) have the advantages of the conventional transformer, the regulatory abilities of
power electronic converters, and reduce the impact of the grid. The impacts of the existing grid are
voltage sag, voltage swell, harmonic distortion, and voltage unbalanced. The power electronic converter
has a controllable advantage such as regulating the voltage and can transfer only a fraction of the power.
The aim of the paper is to augment the conventional power distribution transformer with a partially rated
power electronic module to enhance flexibility and introduce new features to the distribution transformer.
In this paper, the proposed back-to-back converter included an active front rectifier and a modular
multilevel converter (MMC) was simulated by MATLAB/Simulink software. The proposed back-to-back
converter was used at the primary side of the distribution transformer to compensate for the voltage sag
and swell issues. The simulation results were obtained under different conditions such as various supply
voltages and various loads. Hence, the proposed system has the ability to regulate the output voltage
under various conditions with ±10%
Electrical Engineering: An International Journal (EEIJ)ijccmsjournal
Hybrid transformers (HT) have the advantages of the conventional transformer, the regulatory abilities of
power electronic converters, and reduce the impact of the grid. The impacts of the existing grid are
voltage sag, voltage swell, harmonic distortion, and voltage unbalanced. The power electronic converter
has a controllable advantage such as regulating the voltage and can transfer only a fraction of the power.
The aim of the paper is to augment the conventional power distribution transformer with a partially rated
power electronic module to enhance flexibility and introduce new features to the distribution transformer.
In this paper, the proposed back-to-back converter included an active front rectifier and a modular
multilevel converter (MMC) was simulated by MATLAB/Simulink software. The proposed back-to-back
converter was used at the primary side of the distribution transformer to compensate for the voltage sag
and swell issues. The simulation results were obtained under different conditions such as various supply
voltages and various loads. Hence, the proposed system has the ability to regulate the output voltage
under various conditions with ±10%.
Similar to seminar report on power quality monitoring (20)
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This document contains 20 multiple choice questions from a GATE EE exam. It covers topics in signals and systems, circuits, electromagnetic theory, machines, and instrumentation. For each question, the full question and multiple choice options are provided, along with the solution and explanation for the correct answer.
This document contains 30 multiple choice questions (MCQs) from a GATE EE exam, along with explanations of the answers. The MCQs cover topics in electrical engineering including circuits, signals and systems, electromagnetics, power systems and electronics. Each question is one mark and the correct answer is indicated. The explanations provide the working to arrive at the right option. This document serves as a practice resource for the GATE EE exam, with concise explanations of the reasoning behind each answer.
This document contains 30 multiple choice questions from a GATE EE exam, along with explanations for the answers. It discusses topics related to electrical engineering, including circuits, electromagnetism, power systems, and electrical machines. The questions range from basic circuit analysis and energy calculations to more complex topics involving synchronous generators, induction motors, and HVDC transmission systems. The document is intended as a practice resource for the GATE EE exam.
Series & shunt compensation and FACTs Deviceskhemraj298
Series compensation is used to improve the performance of extra high voltage transmission lines by connecting capacitors in series with the line. It allows for increased transmission capacity and improved system stability by reducing the phase angle between sending and receiving end voltages for the same power transfer. Shunt compensation controls the receiving end voltage by connecting shunt capacitors or reactors to meet reactive power demand and prevent voltage drops or rises. Flexible AC transmission systems use high-speed thyristors to switch transmission line components like capacitors and reactors to control parameters like voltages and reactances to optimize power transfer.
This document is the copyright page and contents for a book on extra high voltage AC transmission engineering. It lists the book's copyright as belonging to NewAge International Publishers and notes that no part can be reproduced without written permission. The dedication is to the author's mother and sister for overcoming cancer. It also contains brief introductions and acknowledgements from contributors, including the book's director and others who assisted. The contents provide an outline of the book's 10 chapters which cover topics like line parameters, voltage gradients, corona effects, fields, waves, lightning protection, and overvoltages from switching.
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The document discusses distributed generation and voltage stability in power distribution systems. It introduces distributed generation as small-scale power generation located near customers. Benefits include improved reliability, power quality, and economic benefits. Challenges include higher costs and integrating variable generation. Voltage stability ensures acceptable voltage levels across the distribution system. As systems operate closer to capacity, voltage stability becomes important to prevent blackouts from voltage collapse. The document examines static and dynamic voltage stability and factors influencing stability.
Bhel haridwar vocational training report block 1khemraj298
This document provides an overview and summary of the author's vocational training report at Bharat Heavy Electricals Limited (BHEL) in Haridwar, India. It acknowledges those who supported the training. The index outlines sections on BHEL's contributions to different sectors, an overview of the BHEL plant in Haridwar, and a focus on turbo generators. Key components of turbo generators discussed include the stator, rotor, bearings, cooling system, and excitation system.
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This was our 9th Sem Design Studio Project, introduced as Conservation of Taksar Bazar, Bhojpur, an ancient city famous for Taksar- Making Coins. Taksar Bazaar has a civilization of Newars shifted from Patan, with huge socio-economic and cultural significance having a settlement of about 300 years. But in the present scenario, Taksar Bazar has lost its charm and importance, due to various reasons like, migration, unemployment, shift of economic activities to Bhojpur and many more. The scenario was so pityful that when we went to make inventories, take survey and study the site, the people and the context, we barely found any youth of our age! Many houses were vacant, the earthquake devasted and ruined heritages.
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UNIT I INCEPTION OF INFORMATION DESIGN
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Best Practices of Clothing Businesses in Talavera, Nueva Ecija, A Foundation ...IJAEMSJORNAL
This study primarily aimed to determine the best practices of clothing businesses to use it as a foundation of strategic business advancements. Moreover, the frequency with which the business's best practices are tracked, which best practices are the most targeted of the apparel firms to be retained, and how does best practices can be used as strategic business advancement. The respondents of the study is the owners of clothing businesses in Talavera, Nueva Ecija. Data were collected and analyzed using a quantitative approach and utilizing a descriptive research design. Unveiling best practices of clothing businesses as a foundation for strategic business advancement through statistical analysis: frequency and percentage, and weighted means analyzing the data in terms of identifying the most to the least important performance indicators of the businesses among all of the variables. Based on the survey conducted on clothing businesses in Talavera, Nueva Ecija, several best practices emerge across different areas of business operations. These practices are categorized into three main sections, section one being the Business Profile and Legal Requirements, followed by the tracking of indicators in terms of Product, Place, Promotion, and Price, and Key Performance Indicators (KPIs) covering finance, marketing, production, technical, and distribution aspects. The research study delved into identifying the core best practices of clothing businesses, serving as a strategic guide for their advancement. Through meticulous analysis, several key findings emerged. Firstly, prioritizing product factors, such as maintaining optimal stock levels and maximizing customer satisfaction, was deemed essential for driving sales and fostering loyalty. Additionally, selecting the right store location was crucial for visibility and accessibility, directly impacting footfall and sales. Vigilance towards competitors and demographic shifts was highlighted as essential for maintaining relevance. Understanding the relationship between marketing spend and customer acquisition proved pivotal for optimizing budgets and achieving a higher ROI. Strategic analysis of profit margins across clothing items emerged as crucial for maximizing profitability and revenue. Creating a positive customer experience, investing in employee training, and implementing effective inventory management practices were also identified as critical success factors. In essence, these findings underscored the holistic approach needed for sustainable growth in the clothing business, emphasizing the importance of product management, marketing strategies, customer experience, and operational efficiency.
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seminar report on power quality monitoring
1. 1
CHAPTER 1
INTRODUCTION
The aim of the power system has always been to supply electrical energy to customers.
Earlier the consumers of electrical energy were mere acceptors. Interruptions and other voltage
disturbances were part of the deal. But today electric power is viewed as a product with certain
characteristics which can be measured, predicted, guaranteed, improved etc. Moreover it has
become an integral part of our life. So the quality of the power supply has gained much
importance. The term ‘power quality’ emerged as a result of this new emphasis placed on the
customer utility relationship.
The fact that power quality has become an issue recently does not mean that it was not
important in the past. Utilities all over the world have for decades worked on the improvement of
what is now known as power quality. In the recent years, users of electric power have detected
an increasing number of drawbacks caused by electric power quality variations. These variations
already existed on the electrical system but only recently they are causing serious problems. This
is due to the increased sensitivity of equipments and devices used by customers. These end user
equipments are more interconnected in networks and industrial processes, that the impact of a
problem with any piece of equipment is much more severe. Also power quality of power systems
affects all connected electrical and electronic equipments and is a measure of deviations in
voltage, current, frequency, temperature, force, and torque of particular supply systems and their
components.
To fulfill the demand of required supply, the world is under tremendous pressure for
alternative sources of energy and has been inclined towards sustainable energy for future source
of energy. The energy sources like solar energy, wind energy, hydroelectric power, tidal power,
geothermal power and wave power are all important types of renewable energy. However if
these energy sources are coupled with the energy efficacy it is termed as sustainable energy
sources. Sustainable Energy is the provision of energy such that it meets the needs of the future
without compromising the ability of future generations to meet their own needs. It is required to
have more efficient means of converting and utilizing these energy. This will depend on the
quality of power supplied and the impact of end user equipments on that power. But power
2. 2
electronic equipments are mostly used in sustainable and renewable energies in different stages
for acquisition and conversion or inversion into useable form. Due to increasing sensitivity of the
equipments and devices used by the customers, power qualities of sustainable energy are
affected.
Poor Power Quality results in high costs and that is gradually rising. The poorer the
Power Quality, the more would be the initiatives required from concerned parties and regulating
bodies to adopt corrective measures to ensure better Power Quality. As a consequence, the
economy of a country is largely affected with even low tech industries suffering serious financial
losses. Especially for successful sustainable energy programe, Power Quality Monitoring can
help identify the cause of power system disturbances and the underlying problem conditions on a
system before they cause interruptions and disturbances. Due to this many power utilities
perform power quality monitoring as an essential service for their main customers. Essential
capabilities of a power quality monitoring system are reduced cost and remote data transmission
capability.
With the electrical industry undergoing change, increased attention is being focused on
reliability and power quality. Power providers and users alike are concerned about reliable
power, whether the focus is on interruptions and disturbances or harmonic distortion or flicker.
One of the most critical steps in ensuring reliability is monitoring power quality. Power quality
monitoring can help to identify the cause of power system disturbances and even help to identify
problem conditions before they cause interruptions or disturbances. Hence power quality
monitoring is a multi-pronged approach to identifying, analyzing, and correcting power quality
problems. To improve power quality with adequate solutions, it is necessary to know what kinds
of disturbances occurred. A power quality monitoring system that is able to automatically detect,
characterize and classify disturbances on electrical lines is therefore required. With power
quality monitoring, power engineers can eliminate some of their troubleshooting headaches.
3. 3
CHAPTER 2
POWER QUALITY
2.1 DEFINATION
The definition of power quality given in the IEEE dictionary is as follows
“Power quality is the set of parameters defining the properties of the power supply as delivered
to the user in normal operating conditions in terms of the continuity of voltage and voltage
characteristics”.
Modern electronic and power electronic devices are not only sensitive to voltage
disturbances; it also causes disturbances for other customers. These devices become the source
and victims of power quality problems. As such the term power quality is used to define the
interaction of electronic equipments within the electrical environment.
2.2 CAUSES OF POWER QUALITY PROBLEMS
The causes of power quality problems can be many. It is often difficult to point an exact cause
for a specific problem. Power quality monitoring equipments comes to aid in such situations.
Most of the causes of power quality problem can be divided into two categories
Internal causes
Approximately 80% of electrical problems originate within a business facility. Potential culprits
may include large equipments start or shut down, improper wiring and grounding, overloaded
circuits or harmonics.
External causes
About 20% of power quality problems originate with the utility transmission and distribution
system .The most common cause is a lightning strike; other possibilities include equipments
failure, vehicle accidents, weather conditions, neighboring business and even normal operation
of utility equipments.
4. 4
2.3 POWER QUALITY DISTURBANCES
Power quality is concerned with the deviation of the voltage from the ideal waveform or the
deviation of the current from the ideal waveform. Such a deviation is called a power quality
phenomena or disturbances. It is important to first understand the kinds of power quality
disturbances that can cause problems with the sensitive loads. Categories of these disturbances
must be developed with a consistent set of definitions, so that the measurement equipments can
be designed in a consistent manner. Power quality phenomena can be divided into two basis
categories.
Steady state variations
A characteristic of voltage or current is never exactly equal to its nominal or desired value.
The small deviations from the desired value are called voltage or current variations. A property
of any variation is that it has value at any moment in time. Monitoring of variations thus has to
take place continuously.
Events
Occasionally, the voltage or current deviates significantly from the nominal or ideal wave
shape. These sudden deviations are called events. Monitoring of events take place by using a
triggering mechanism where recording of voltage or current starts the moment, a threshold is
exceeded.
STEADY STATE VARIATIONS
This category includes voltage and current variations which are relatively small
deviations of voltage and current characteristics around their nominal or ideal values. The two
basic characteristics are magnitude and frequency. On average voltage magnitude and voltage
frequency are equal to their nominal value but they are never exactly equal. Variations must be
measured by sampling the voltage and current over time. Information is best presented as a trend
of the quantity over time and then analyzed using statistical methods. An overview of voltage
and current variations are given below:
5. 5
Voltage fluctuation
The fast changes or swings in the steady state voltage magnitude are called voltage
fluctuation. The change in voltage magnitude can be due to variations of total load of a
distribution system, action of transformer tap changers, switching of capacitor banks. If the
variations are large enough or in a certain critical frequency range, the performance of the
equipment can be affected.
Fig. 2.1
Voltage and current unbalance
Unbalance or 3 phase unbalance is the phenomenon in a 3 phase system in which the
RMS values of voltages and phase angles between consecutive phases are not equal. The
primary source of voltage unbalance is the unbalanced load. This can be due to an uneven
spread of low voltage customers over the three phases but more commonly unbalance is due
to a large single phase load.
Harmonic voltage and current distortion
Widespread use of electronic equipment in today’s commercial and industrial
environments make harmonic distortion an important but complicated power quality issue.
6. 6
Any power supply that converts AC to DC power will have a much distorted waveform at the
supply. The current waveform is always a picture of the way a load reacts to the AC supply.
The distorted voltage created by the return current through the impedance of the cable and
switchgear can cause the voltage waveform to distort. This voltage distortion will affect
every device connected to the corrupted circuit. Harmonic distortion of voltage and current
result, from the operation of non-linear loads and devices in the power system.
Fig. 2.2 Harmonic Distortion
High frequency voltage noise
The non-periodic components in supply voltage can be called ‘noise’. Distinguishing
noise from other components is not always simple. An analysis is needed only in case where
noise leads to some problem with power system or end user equipments. Electrical noise can
be defined as the high frequency interference caused by a number of factors like arc welding
or operation of electrical motor.
7. 7
EVENTS
Events are the phenomena which happen once in a while. Power quality events are the
disturbances which can lead to the tripping of equipments, interruptions of production or plant
operation or endanger power system operation. Events are measured by a triggering mechanism.
An overview of various events is given below.
Interruptions
A supply interruption is a condition in which the voltage at supply terminals is close to
zero. Interruptions are normally initiated by faults which subsequently trigger protection
measures. Interruptions can be subdivided based on their duration, thus based on the way of
restoring the supply.
1. Sustained Interruptions: These kinds of interruptions are terminated through manual
restoration or replacement of faulted components.
2. Temporary Interruptions: This refers to interruptions lasting less than 2 minutes. This
interruption is terminated through automatic restoration of pre-event situation.
3. Momentary Interruptions: These interruptions are terminated through self-restoration.
E.g. Interruption due to transients and other self-restoring events.
Fig. 2.3
8. 8
Voltage sags / swells
A sag or swell is a decrease or increase in the RMS value of voltage ranging from a half
cycle to few seconds. The most likely kind of power quality problem is the voltage sag. Short
duration under voltages is called ‘voltage sags’ whereas, longer duration under voltages are
referred to as ‘under voltage’. Likewise over voltages of very short duration and high
magnitude are called ‘voltage swells’. Longer duration over voltage is called as ‘over
voltage’. Short duration voltage variations include variations in the fundamental frequency
voltage that lasts less than 1 minute.
Fig. 2.4
9. 9
Transients
Transients are sub cycle disturbances of very short duration that vary greatly in
magnitude. Transients are used to refer to fast changes in the system voltage or current with
duration less than .5 cycles. Transients can be measured by triggering on the abnormality
involved. When transients occur, thousands of voltage can be generated into the electrical
system causing problems for equipments down the line. Transients can be divided into 2
categories:
1. Impulsive transient: Lightning striking a distribution line is normally an impulsive
transient where there is a large deviation of the wave form for a very short duration in
one direction, followed possibly by a couple of much smaller transients in both
directions.
2. Oscillatory transient: An oscillatory transient is one where there is a ringing signal or
oscillation following the initial transient. E.g.: switching of power factor correction
capacitor is considered the most prevalent type of transient.
Fig. 2.5
10. 10
2.4 INCREASED INTEREST IN POWER QUALITY
Power quality is an increasingly important issue for all business. A recent study by IBM
showed that power quality problems cost US business more than $15 billion a year. The
increased interest in power quality has resulted in significant advances in monitoring equipments
that can be used to characterize disturbances and power quality variations. The recent increased
interest in power quality can be explained in a number of ways.
• Equipments have become more sensitive to voltage disturbances
The electronic and power electronic equipments have especially become much more
sensitive to voltage disturbances than their counterparts 10 or 20years ago.
• Equipments cause voltage disturbances
Modern electronic and power electronic equipments are not only sensitive to voltage
disturbances but also cause disturbances for other customers. E.g. Non-sinusoidal current
drawn by rectifiers and inverters.
• Technical challenge taken up by utilities
Designing a system with a high reliability of supply at a limited cost is a technical challenge
which appealed too many in the power industry and hopefully still does in the future.
• Power quality can be measured.
The availability of electronic equipments to measure and show wave forms has certainly
contributed to the interest in power quality.
2.5 IMPACTS ON GLOBAL ECONOMY
The cost of energy or a KWH not supplied because of an outage is much higher than the
cost of a KWH that is supplied when needed. The global bill for poor power quality is more than
500 billion euros per year which is 50% of the turnover of the global electricity sector. For many
business uses, the cost of poor Power Quality is higher than the electricity bill and the cost is
rising. The global average energy consumption is steeply rising.
11. 11
Fig. 2.6 Projections of Indian average energy consumption
Due to high average increase of energy demand, India needs to have sustainable energy
productions to meet the huge energy requirements. The Government of India is trying to
accelerate solar power generation. By January 2014 the installed grid connected solar power had
increased to 2,208.36 MW, and India expects to install an additional 10,000 MW by 2017 and a
total of 20,000 MW by 2022. Poor Power Quality has serious impact on Indian economy. A joint
study by the manufacturers association of information technology(MAIT) and emersion network
power(India) has thrown up the finding that network power downtime costs Indian economy
more than Rs.43000 crores annually(2008) and this has been steeply rising. Similarly, economic
cost of outages of Bangladesh amounted to 1.72% (US $778millions) of the Country GDP in
2001. Industrial losses due to poor Power Quality had been estimated as $150- $200 billion
dollars for European Union (2001). Therefore, an efficient and intelligent monitoring is essential
to avoid staggering economic losses due to poor power quality and to meet the challenges.
12. 12
CHAPTER 3
POWER QUALITY MONITORING (PQM)
3.1 SOLAR ENERGY IN INDIA AND PQ MONITORING
Solar Energy is one of the cleanest and greenest technologies. Solar electric panels
produce DC. Necessary conversion is done for AC applications. A solar electric system may be
completely independent of the grid or designed to primarily feed power into the grid. The solar
radiation in India is very much satisfactory and most parts are suitable for generating power from
Solar Energy. In such case it is essential for India to install efficient power quality monitoring
systems to maintain quality and undertake exact mitigations in time. The support extended by
Government of India by way of providing attractive incentives under Jawaharlal Nehru National
Solar Mission (JNNSM) is generating significant interest in Solar Energy. India has
Geographical advantage with excellent solar radiation across the Country. In fact Rajasthan has
been recently termed as amongst the best in the world for Solar Energy. As an alternative source
of energy efforts are made to have larger production units from solar, wind mills sources etc. But
many systems (utility/customer) are affected due to absence of an effective PQM programme.
Integration of sustainable energy with the grid and use of power electronics, power quality
problems have increased in manifold. Monitoring within an industrial, residential or domestic
unit can reveal the origin of problems and give the necessary information for their solution.
Efficient power quality monitoring will provide the information needed to validate compliance,
improve system stability, and minimize unplanned downtime. It is therefore an important issue
for the successful and efficient operation of existing as well as future energy systems. In such
conditions, monitoring of power quality is the real challenge. An intelligent power quality
monitoring system is an essential requirement of the future energy system. The PQM should be
capable to detect most (and almost all) of the power quality events and disturbances. Intelligent
PQM is the need for smart grid due to principal functionality characteristics of Smart Grids.
13. 13
3.2 OBJECTIVES OF PQ MONITORING
The objectives of a monitoring program determine the choice of measuring equipments
and triggering thresholds, the methods for collecting data, data storage and analysis requirements
and the overall level of effort needed. General classification of objectives for power quality
monitoring is explained in the following section.
Proactive approach:
This approach of monitoring is intended to characterize the system performance. A power
producer may find this objective important because this helps to understand the system
performance and then be able to match the system performance with customer needs.
Reactive approach:
This kind of monitoring is intended to characterize a specific problem. Many services
solve power quality problems by performing short term monitoring at specific customers or at
different loads.
3.3 DEVLOPMENT OF SYSTEM
The aim of this work is to develop a method that is suitable for efficient monitoring of
power qualities in sustainable energy system like solar energy etc. The emphasis is therefore on
low computational power required to perform the necessary calculations. Stress is also laid on
the possibility to detect as many categories of PQ disturbances as possible.
An intelligent power monitoring system can be developed by designing virtual
instruments using LabVIEW software and NI’s DAQ system and sensors. Along with LabVIEW,
Higher order statistics (HOS) and quadratic discriminant analysis techniques are employed to
classify and analyze the huge amount of acquired data to determine the condition of the
waveforms. The system shows fast response with accuracy in monitoring and analysis of the
desired power qualities.
Initially, the distortions have been simulated in the labs and measured with the help of the
developed virtual instruments (VIs) using graphical programming in LabVIEW. Different types
of disturbances measurements are done with front panel created on PC monitor. The huge
14. 14
amount of acquired data has been analyzed using quadratic discriminant analysis technique to
determine the quality of the supply. The quadratic function is estimated treating a sample from
the data as a training data. The data can be exported in different formats in a text file or directly
in common software products like Excel etc. The test results of the simulated and the prototype
system show the desired performance of the system and thus validate the proposed technique.
The beauty of the system is that it can be used for monitoring of power qualities in both existing
power system and sustainable energy systems with provisions for switching-over.
In this application, we generate a graphical user interface through which the user can
monitor and adjust different parameters to customize the monitoring tasks. On the other hand, a
National Instruments Data Acquisition card is chosen to interface the analog AC signal as a
second step after using step-down transformer along with voltage divider circuit for signal
conditioning. For voltage measurements, magnetic voltage transformers are used (upto 5 KHz).
However current probes and Hall Effect voltage transducers are employed to acquire voltage and
current signals for accurate sensing.
Fig. 3.1 Block diagram of power quality monitoring system
15. 15
3.4 POWER QUALITY MONITORS
The first step to troubleshooting power quality problems is to have a monitor that
accurately measures voltage and current waveforms. The role of monitor for troubleshooting
power quality problems is undeniable. Power quality monitoring devices come in a variety of
shapes and sizes. Commercially available monitors fall into two categories: 1) portable
monitors and 2) permanent monitors.
PORTABLE MONITORS
Handheld and portable instruments have made great improvements in testing capability in
recent years and are helpful in uncovering small localized problems. But these are used for
troubleshooting after an event has taken place. Installing a power quality monitor after the
occurrence of the event tells us little about the past. Portable monitors are again subdivided into
two classes:
1. Voltage recorders
These instruments record voltage and current strip chart data. Portable monitors are used for
continuous monitoring of steady state voltage variations. These recorders digitize voltage and
current signals by taking samples of voltage and current over time. The most important factor
to consider when selecting and using a voltage recorder is the method of calculation of the
RMS value of the measured signal.
2. Disturbance analyzer
Disturbance analyzer and disturbance monitors form a category of instruments which have
been developed specifically for power quality measurements. The analyzers are designed to
capture events affecting sensitive devices. They typically can measure a wide variety of
system events from very short duration transients to long duration outages. Thresholds can
be set and the instrument is left unattended to record disturbances over a long period of
time. Recording starts the moment, a threshold value is exceeded.
16. 16
Fig. 3.2 PORTABLE MONITOR
PERMANENT MONITORS
In the past, measurement equipments were designed to handle either the events or steady
state variations. With advances in processing capability, new instruments have become available
that can characterize the full range of power quality variations. The new challenge involves
characterizing all the data in a convenient form, so that it can be used to identify and solve
problems. This highlights the features of permanent monitors.
Permanently installed full system monitors strategically placed on pieces of equipments
throughout the facility, lets the users know, what happened, where it happened as soon as it
happened. The main feature of these kinds of monitors is that they characterize full range of
power quality variations. They record both the triggered and sampled data. Triggering is based
upon the RMS thresholds for RMS variations and on wave shape for transient variation. The
simplest monitoring system could be a self-contained circuit monitor; however the real value of
monitoring is in automatic data downloading from the measuring instruments. Monitoring
system should fully utilize the networking infrastructure. A more apt term for these efficient
monitoring systems would be ‘real time monitoring systems’.
18. 18
CHAPTER 4
ANALYSIS OF POWER QUALITY MEASUREMENTS
4.1 MONITORING OBSERVATIONS OF POWER QUALITIES
A large number of readings were recorded during observations of monitoring performed
by the developed system. Fig. 4.1 show some typical distortions or disturbances captured during
monitoring of simulated disturbances in the laboratory.
Fig. 4.1 PQ disturbances monitored by the developed method.
The waveforms captured show different power quality events or disturbances, including
voltage sag, swell, interruptions, transients, harmonics etc.
The table I shows the summary report of power quality monitoring of 200 KVA UPS
Input at NIT Silchar Systems. And table II shows the summary report of power quality
monitoring of 200 KVA UPS Output at NIT Silchar System.
20. 20
The tables I and II show extract of actual recordings, which would be helpful for assessment of
power quality of the systems. UPS input has about 15% input current harmonics distortion as it
has 12 pulse rectifier at the input. Similarly it has been observed that the blower motors which
have thyristor rectifiers at input are affected due to a lot of input current harmonic distortion.
Thus this system is showing monitoring of harmonics (THD), supply voltage and current.
4.2 DATA ANALYSIS
Acquired data can be exported in different formats in a text file, HTML or directly in
common software products or evaluation software provided by National Instruments. It has been
found during investigations and analysis that the sources of disturbances can be determined by
simultaneous measurement or monitoring of voltage and current. Analysis tools for processing
measured data present the information as individual events i.e. disturbance wave forms, trends or
statistical summaries. By comparing the captured events with libraries of typical power quality
variation characteristics and correlating with system events, causes of variations can be
determined. The data analysis system should be flexible enough to handle data from a variety of
monitoring equipments and maintain a database that can be used by many different applications.
4.3 BENEFITS OF POWER QUALITY MONITORING
The benefits of power quality monitoring are many. The following section mentions some of
them.
Ensures power system reliability.
Identify the source and frequency of events.
Helps in the preventive and predictive maintenance.
Evaluation of incoming electrical supply and distribution to determine if power quality
disturbances are impacting.
Determine the need for mitigation equipments.
Reduction of energy expenses and risk avoidances.
Process improvements – monitoring systems allows to identify the most sensitive
equipments and install power conditioning systems where necessary.
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CHAPTER 5
CONCLUSION
Global economy has been affected due to poor PQ of the supply systems. Power qualities
of sustainable energy are also affected due to increasing sensitivity of the equipments and
devices used by the customers, and need proper monitoring and analysis for mitigation purposes.
Traditional monitoring methods are based on the RMS measurements and constrained by their
accuracies. Recently proposed approaches for automated detection and classification of power
quality disturbances are based on wavelet analysis, artificial neural networks, hidden Markov
model and bispectra. The use of such advanced techniques makes the power quality monitoring
system more accurate and the power system more reliable.
The configuration complexity of a monitoring system depends primarily upon the number
of instruments used to acquire information and the number of people who need to utilize it. The
simplest monitoring system could be a self-contained circuit monitor built into a sensitive load.
However the real value of monitoring system is in automatic data downloading from the
measuring instruments and hence today, a lot of emphasis is given on the design of ‘real time
monitoring systems’.
5.1 FUTURE OF POWER QUALITY
In 10 years’ time, it may well be that equipment has become fully compatible with the power
supply and does not cause any disturbance to the customers. However, there is no indication that
this will happen soon. So right now the emphasis is on mitigation equipments and on intelligent
power quality monitoring systems which enables the automatic classification and analysis of the
measured data.