INVESTIGATING VOLTAGE RESTORATION AND POWER EXPORT IN A DISTRIBUTION SYSTEM WITH SERIES COMPENSATOR USING DISTRIBUTED GENERATION

摘要

In recent years, the nonlinear loads and complexity of control systems in industrial processes have triggered the Power Quality (PQ) problems in the distribution network. The major aim of PQ enhancing techniques is to maintain a specified voltage magnitude at a desired frequency for sensitive loads irrespective of the faults in the power distribution network. This is possible only by ensuring that an uninterrupted flow of power is maintained at proper voltage levels. Electrical utilities are looking for solutions to ensure high quality power supplies to their consumers. Dynamic Voltage Restorer (DVR) is a series compensator used to mitigate voltage sags and to restore load voltage to its rated value, thus enabling the consumer to continuously receive clean power. This paper presents a mathematical model for leading series voltage injection (LSV1) to mitigate sags, thereby achieving the improvement of utility power factor as well as power sharing between the DVR and the utility. The power sharing will be as per requirement to compensate the sags considering the available distributed generation (DG). The approach of mitigating voltage sags and power export using the concept of LSVI is suitable for those locations where phase shift in the voltage will not cause any problem. The MATLABdD/Simulink® SimpowerSystem tool box has been used to validate the proposed mathematical model for balanced and unbalanced sag in the utility voltage. Both linear as well as nonlinear loads have been considered for analysis purposes. THD measured in all simulated cases was found to be below 5% with sag detection and a mitigation time less than 20 msec (1 cycle). This shows the satisfactory performance of the proposed LSVI concept for sag mitigation and harmonic reduction.