Power Quality Improvement by Using Statcom Control Scheme

What is it about?

A B S T R A C T “Electric Power Quality (EPQ) is a term that refers to maintaining the near sinusoidal waveform of power distribution bus voltages and currents at rated magnitude and frequency.” Today customers are more aware of the seriousness that the power quality possesses, this prompts the utilities to assure good quality of power to their customer. The power quality is basically customer-centric. The increased focus on utilities toward to maintaining reliable power supply by employing power quality improvement tools has reduced the power outages and blackout considerably. Good power quality is the characteristic of reliable power supply. Low power factor, harmonic pollution, load imbalance, fast voltage variations are some common parameters which are used to define the power quality. If the power quality issues are not checked, i.e., the parameters that define power quality doesn't fall within the predefined standards than it will lead to high electricity bill, high running cost in industries, malfunctioning of equipments, challenges in connecting renewables. Capacitor banks, FACTS devices, harmonic filters, SVC’s, STATCOM are the solutions to achieve the power quality. The performance of Wind turbine generators is affected by poor quality power, at the same time these wind power generating plant affects the power quality negatively. This paper presents the STATCOM system with the BESS and studies the impact on the power quality in a system which consist of wind turbine generator, nonlinear load, hysteresis controller for controlling the operation of STATCOM and grid. The model is simulated in the MATLAB/Simulink. This scheme mitigates the power quality issues, improves voltage profile and also reduces harmonic distortion of the waveforms. BESS level out the imbalances caused by real power due to intermittent nature of wind power available due to varying wind speeds.

Featured Image

Why is it important?

Power Quality Improvement by Using Statcom Control Scheme in Wind Energy Generation Interface to Grid *Dr. Sheeraz Kirmani1, Brijech Kumar2 1, 2Department of Electrical Engineering, JamiaMilliaislamia, New Delhi, India E mail: sheerazkirmani@gmail.com , E mail: bknsea@icloud.com A B S T R A C T “Electric Power Quality (EPQ) is a term that refers to maintaining the near sinusoidal waveform of power distribution bus voltages and currents at rated magnitude and frequency.” Today customers are more aware of the seriousness that the power quality possesses, this prompts the utilities to assure good quality of power to their customer. The power quality is basically customer-centric. The increased focus on utilities toward to maintaining reliable power supply by employing power quality improvement tools has reduced the power outages and blackout considerably. Good power quality is the characteristic of reliable power supply. Low power factor, harmonic pollution, load imbalance, fast voltage variations are some common parameters which are used to define the power quality. If the power quality issues are not checked, i.e., the parameters that define power quality doesn't fall within the predefined standards than it will lead to high electricity bill, high running cost in industries, malfunctioning of equipments, challenges in connecting renewables. Capacitor banks, FACTS devices, harmonic filters, SVC’s, STATCOM are the solutions to achieve the power quality. The performance of Wind turbine generators is affected by poor quality power, at the same time these wind power generating plant affects the power quality negatively. This paper presents the STATCOM system with the BESS and studies the impact on the power quality in a system which consist of wind turbine generator, nonlinear load, hysteresis controller for controlling the operation of STATCOM and grid. The model is simulated in the MATLAB/Simulink. This scheme mitigates the power quality issues, improves voltage profile and also reduces harmonic distortion of the waveforms. BESS level out the imbalances caused by real power due to intermittent nature of wind power available due to varying wind speeds. CONTEMPORARY URBAN AFFAIRS (2017) 1(3), 31-37. https://doi.org/10.25034/ijcua.2018.3676 www.ijcua.com Copyright © 2017 Contemporary Urban Affairs. All rights reserved. I. Introduction Power is the very crucial input for the growth of any economy. Therefore, it is considered as a core industry as it facilitates development across various sectors, such as agriculture, manufacturing, railways, education, commercial, etc. to expel economic development. To meet the high GDP rates, the energy needs of the country are inevitable. Renewable energy is characterized as intermittent and variability which presents various challenges in its grid integration for maintaining grid stability and security. Intermittent/variable nature of RE source results in wide variation in quantum and direction of power flow on the inter-state high capacity transmission corridors. This requires placement of dynamic reactive compensation in the form of dynamic reactive compensation in the form of STATCOM/svc at strategic locations to provide dynamic support for smooth operation and to maintain grid security. The integration wind into existing electrical power system induces power quality problems like voltage regulation, stability, harmonic distortion, voltage sag/swell and also power factor. The power quality is always customer-focused measure and is greatly affected by the operation of a distribution and transmission network. In this proposed scheme one of the Flexible AC transmission system (FACTS) device, i.e., Static-Compensator (STATCOM) is connected at the point of common coupling (PCC) with a battery energy storage system (BESS) to mitigate power quality problems. Since STATCOM connected to the grid provides reactive power support to wind generator and to load. The BESS is integrated to sustain real power source under fluctuating wind or solar power. In the event of if there is any sudden load change or change in voltage profile like a short circuit in point of common coupling (PCC), a Distribution-STATCOM responds fast and stabilizes the voltage and also helps in order to maintain power quality. II. Problems Related To Power Quality A. Power Quality Issues of Grid Side: At the grid side, the power quality is the responsibility of utility. The utility should make sure that the power matches the customer requirements and should not violate the limits that are specified for the parameters which define the power quality. From the customer point of view, the voltage variations and high content of harmonics in the grid power are highly undesired as they affect the performance of the end equipment. For the IIP’s who have planned the wind power project, the voltage profile of evacuating substation and nearby substations is of prime concern. 1) Voltage variation: Intermittent nature of wind power causes several problems, and one is a variation of the voltage of buses in the region of high wind penetration. Wind generators mostly employed induction generators and power electronic circuits which demand reactive power for operation. Voltage sag/swell is observed where ineffective methods of reactive power management are employed. If the voltage rises beyond the controllable limit, forced tripping of lines carried out, cascaded tripping may destabilize a weak power system. Generally, the power factor of evacuating substation is maintained near to unity preferably slightly lagging. 2) Voltage Transients: B. Power Quality Issues of WTG Side In the wind energy generating system the power quality primarily concerned with the quality of current waveform which is being drawn or generated by the wind turbine. Poor power quality affects the performance of the loads connected to the grid. 1) Reactive Power Consumption: Induction generators draw reactive power to produce its working flux while generating active power at the same time. As induction generators are most widely preferred in wind turbine generators, collectively a wind farm demand a huge amount of reactive power. As the wind speed is not constant, in such a case the use of electronic power conversion devices in wind turbine generators becomes inevitable to achieve a rotor speed for maximum extraction of energy from wind. The operation of power electronic devices also requires reactive power. To avoid voltage stability problem either STATCOM or capacitor arrangement is used to supply this demand of reactive power. 2) Current Harmonics Generation: Capacitors are used as an essential part of the wind turbine generators for supplying reactive power demand. Capacitor switching may cause large voltage transient.

Perspectives