Step-less voltage regulation on radial feeder with OLTC transformer-DVR hybrid

On Load Tap Changing (OLTC) transformer acts to regulate the load voltage on load by increasing or decreasing the input power flow whereas, the capacity supported DVR regulates the voltage with reactive power transfer. As the OLTC operates in discrete steps, it brings in quantum jump in both the phase and magnitude of voltage at PCC, whereas sensitive load requires step-less operation. For step-less voltage regulation over extended range a hybrid combination of DVR with OLTC control of transformer is envisaged. The paper presents a simple and fast control strategy for hybrid control of both OLTC and DVR to desire stepless voltage regulation of the radial feeder under load perturbation and source side disturbances. A simple control algorithm is proposed which control the DVR and OLTC transformer to regulate the voltage in the radial feeder. Simulated results under MATLAB environment are presented to validate the effectiveness of control scheme.