New control technique applied in dynamic voltage restorer for voltage sag mitigation

Abstract

Abstract:The Dynamic Voltage Restorer (DVR) was a power electronics device that was able to compensate voltage sags on critical loads dynamically. The DVR consists of VSC, injection transformers, passive filters and energy storage (lead acid battery). By injecting an appropriate voltage, the DVR restores a voltage waveform and ensures constant load voltage. There were so many types of the control techniques being used in DVR for mitigating voltage sags. The efficiency of the DVR depends on the efficiency of the control technique involved in switching the inverter. Problem statement: Simulation and experimental investigation toward new algorithms development based on SVPWM. Understanding the nature of DVR and performance comparisons between the various controller technologies available. The proposed controller using space vector modulation techniques obtain higher amplitude modulation indexes if compared with conventional SPWM techniques. Moreover, space vector modulation techniques can be easily implemented using digital processors. Space vector PWM can produce about 15% higher output voltage than standard Sinusoidal PWM. Approach: The purpose of this research was to study the implementation of SVPWM in DVR. The proposed control algorithm was investigated through computer simulation by using PSCAD/EMTDC software. Results: From simulation and experimental results showed the effectiveness and efficiency of the proposed controller based on SVPWM in mitigating voltage sags in low voltage distribution systems. It was concluded that its controller also works well both in balance and unbalance conditions of voltages. Conclusion/Recommendations: The simulation and experimental results of a DVR using PSCAD/EMTDC software based on SVPWM technique showed clearly the performance of the DVR in mitigating voltage sags. The DVR operates without any difficulties to inject the appropriate voltage component to correct rapidly any anomaly in the supply voltage to keep the load voltage balanced and constant at the nominal value.

RETRACTED ARTICLE: Dynamic voltage restorer controller using grade algorithm

“…Power quality standards for connection of an inverter to the grid are still under development, since before there have been a few similar high-power applications. In Omar and Rahim (2009), it is that the power quality is determined by the voltage quality, when the voltage is a controlled variable. To deliver a good AC power, the controlled pulse width modulation (PWM) inverter and L-C output filter have to convert a DC voltage source (e.g.…”

Performance comparison of DVR by various compensation methods

“…During transient condition voltage sag is denoted by Vsag. In this condition DVR comes into operation and injects required amount of voltage into the system to bring back to normal state [6].…”

“…Under normal operating conditions when there is no fault on the system DVR operates in standby mode. Whenever fault occurs on the system DVR injects required amount of voltage into the system [5,6]. This DVR injects the missing voltage and helps in improving the performance of the system.…”

Simulation and Implementation of DVR for Voltage Sag Compensation

“…The DVR was first installed in 1966 [16]. It is normally installed in a distribution system between the supply and the critical load feeder [17]. Its primary function is to boost up the load-side voltage in the event of a disturbance in order to avoid any power disruption to that load [18,19].…”