Voltage Oriented Control and Direct Power Control Strategies in Solving under and Overvoltage Conditions for Heavy Load Application on Malaysian Distribution Representative Network

This paper proposed two PWM control scheme which is the Voltage Oriented Control (VOC) and Direct Power Control (DPC) on a heavy loaded LV-distribution network with photovoltaic (PV) integration in Malaysia. The surge in demand of power supply is overcome by deploying more PV to fulfil the load demand. However, this could give rise to power quality issues that can affect the stability of the grid. The focus in this work is to solve voltage dynamic concern which results in over and undervoltage problems within the distribution network and at the same time to evaluate on the performance of both control schemes under a heavy loaded condition. A 33 kV Malaysian LV-Distribution model integrated with PV is constructed to serve as a base model in this paper. From the base model, a load flow analysis is conducted in order to locate the weakest bus. The two proposed control schemes are introduced into the weakest bus in the grid system, and its performance of the controller will be evaluated based on three aspects such as compensation margin, voltage and current total harmonics distortion (vTHD and iTHD) and lastly the compensated voltage levels. It is shown that VOC control scheme has outperformed DPC due to a wider compensation margin and its ability to achieve the desired reference voltage with a faster settling time under heavy loaded condition. Therefore, the proposed PWM control scheme of both VOC and DPC under a heavy load scenario could be set as a benchmark to provide impactful insights and findings towards an actual implementation of the application within a distribution network or distributed generation.