Vasudeo B. Virulkar

Power system flicker analysis, modeling and prototype implementation

This paper proposes a flicker loads modeling and its prototype implementation for validating the mitigation solutions. This laboratory model emulates the performance of commonly encountered flicker generating loads in distribution network such as electric arc resistance welder, wood saw machine, stone crushing machine etc. The modulation amplitude and flicker frequencies values can be assigned by changing the values of passive component such as resistances and inductances of the main load as time varying impedance is the deciding parameter in representing the type of the flicker load. The analogue as well as digital control implementation is presented to emulate the flicker load characteristics. In generalized flicker load algorithm using DSP gives flexibility for different flicker loads emulations from the selectable passive elements. This load can be used to evaluate the performance of flicker mitigating solution in a laboratory as well as for demonstrating the flicker concept to the students.

Mitigation of flicker at wood saw machine with active and reactive power compensation

Voltage flicker, a phenomenon of annoying light intensity fluctuation, caused by rapid change in industrial and domestic load such as saw machine operating periodically has been a major concern for supply utilities and costumers in the vicinity. The sawmill current is of quasi-periodic with a frequency of about 10 Hz causing perceptible flicker. The FACTS devices like SVCs, STATCOM and Custom Power devices like DSTATCOM have been able to solve the voltage flicker problems by rapidly controlling the reactive power. But, control of active power along with reactive power control helps to mitigate the voltage flicker problem more effectively. In this paper, voltage flicker mitigation of wood saw machine with DSTATCOM along with Battery Energy Storage System (BESS) is analyzed using the PSCAD/EMTDC software. The proposed algorithm controls the flicker. The mathematical model of wood saw machine suitable for the flicker phenomenon is presented. The dynamic operation is investigated using this algorithm.

Reactive and real power compensation with DSTATCOM and BESS for mitigation of flicker

Voltage flicker, a phenomenon of annoying light intensity fluctuation, caused by rapid change in industrial and domestic load such as electric arc furnaces (EAF), rolling mills, welding equipments and pumps operating periodically, has been a major concern for supply utilities, electricity regulatory agencies and costumers. The FACTS devices like SVCs, STATCOM and custom power devices like DSTATCOM have been able to solve the voltage flicker problems by rapidly controlling the reactive power. But, control of active power along with reactive power control helps to mitigate the voltage flicker problem more effectively. In this paper, voltage flicker mitigation of electric arc welder with DSTATCOM along with battery energy storage system (BESS) is analysed using the PSCAD/EMTDC software. The proposed algorithm controls the voltage oscillations and fluctuations. The mathematical model of resistance welder suitable for the flicker phenomenon is presented. The dynamic operation is investigated using this algorithm.

Voltage Flicker Mitigation Using STATCOM and ESS

Voltage flicker, a phenomenon of annoying light intensity fluctuation, caused by rapid change in industrial and domestic load such as electric arc furnaces (EAF), rolling mills, welding equipments and pumps operating periodically has been a major concern for supply utilities, electricity regulatory agencies and costumers. SVCs and STATCOM have been able to solve the voltage flicker problems by rapidly controlling the reactive power. But, control of active power along with reactive power control helps to mitigate the voltage flicker problem more effectively. In this paper, voltage flicker mitigation of EAF with STATCOM along with energy storage system (ESS) is presented and performance results of the system using the PSCAD/EMTDC software are analyzed.

DSTATCOM with BESS, an efficient means for flicker mitigation

The voltage flicker, a phenomenon of annoying light intensity fluctuation, caused by rapid change in industrial and domestic load such as electric arc furnaces (EAF), rolling mills, welding equipments and pumps operating periodically has been a major concern for supply utilities, electricity regulatory agencies and costumers. The FACTS devices like SVCpsilas, STATCOM and Custom Power devices like DSTATCOM have been able to solve the voltage flicker problems by rapidly controlling the reactive power. But, control of active power along with reactive power control helps to mitigate the voltage flicker problem more effectively. In this paper, voltage flicker mitigation of electric arc welder with DSTATCOM along with battery energy storage system (BESS) is analyzed using the PSCAD/EMTDC software. The proposed algorithm controls the voltage oscillations and fluctuations. The mathematical model of resistance welder suitable for the flicker phenomenon is presented. The dynamic operation is investigated using this algorithm.

Comparative performance of BESS and SMES in distribution network to improve power quality

The FACTS devices, like STATCOM, are becoming a part of the modern power system to improve the power system operation and power quality problems. Integrating the battery energy storage system (BESS)/superconducting magnetic energy storage (SMES) across the dc bus of the STATCOM can provide effective modulation of the real and reactive power. The dynamics of each of these differ because of their nature of energy storage. In this paper, comparative dynamic performances of these devices across the STATCOM are presented. The control strategy is proposed to integrate these devices to improve the active power management within the constraints of source supply to take the advantage of off-peak load condition. The simple hysteresis controller ensures the unity power factor and sinusoidal supply current. Proposed controller is designed to regulate the real and reactive power while keeping the dc bus voltage constant in BESS and SMES. Simulation is carried out using realistic power devices to study the dynamic performance of these schemes. The prototype results are given to validate the performance.

Modeling and simulation of flicker due to interharmonics

Interharmonics are spectra components whose frequencies are not integral number of the supply fundamental frequency. When a voltage waveform contains interharmonics, the root mean square (rms) and peak magnitude of the waveform will fluctuate. This is because the periods of the interharmonic components are not synchronous with the fundamental frequency cycle. This fluctuating magnitude is essentially is a form of flicker. If the magnitude is sufficiently large and the fluctuation frequency is in a large perceptible by human eyes, a light flicker will occur. As a result, devices that produce interhamonics have been considered as a major source of light flicker. Variable frequency drives (VFDs) are widely used in various industry applications due to their efficiency and energy cost savings aspect. In spite of advanced technology and improved reliability of modern VFDs, they considered not only as harmonic sources but also interharmonic sources. The interharmonic-flicker curve based on rms and peak magnitude fluctuations and on the IEC flickermeter is presented.