Response coordination of distributed generation and tap changers for voltage support

The recent introduction of the competitive electricity market in many countries has sparked a renew trend in connecting small-size generators into distribution networks. Those new generators together with different other types of equipment such as On-load Tap Changing (OLTC) transformer, shunt capacitors, shunt reactors, etc, will all participate into the voltage regulation process in the power systems. Poor coordination between these devices may cause unnecessary operations, and consequently unnecessary wear, unnecessary energy consumption as well as poor voltage quality. In this paper, we present an innovative strategy to coordinate the voltage control actions in a distribution system with more than one voltage regulating device. The method for voltage control coordination is developed based on the priority level of each regulating device and implemented through communication. A sensitivity-based technique for determining the control zones of the regulating devices has been developed. A practical system with tap changers and distributed generator has been chosen to test the developed control method. Simulations have been carried out extensively on a practical distribution system to show the effectiveness of the method.