Implementation of closed loop voltage control for medium voltage distribution

Queensland legislation requires Distribution Network Service Providers (DNSPs) maintain a steady state voltage of 240V ± 6% at customer premises. With use of sensitive electronic equipment and embedded generation, traditional voltage management solutions may no longer be appropriate. This paper proposes Closed Loop Voltage Control (CLVC) that utilises real time data feedback from substation Supervisory Control and Data Acquisition (SCADA) and Power Quality (PQ) meters to dynamically set the optimal Zone Substation (ZS) OLTC transformer tap. The algorithm acts to reduce ‘out of limits’ voltages at PQ meter locations and hence provide tighter voltage regulation at the network extremities. A software GUI was developed to test CLVC on a distribution network in Regional Queensland, Australia. The OLTC transformer was switched to manual mode and tap actions were initiated on SCADA based on real time CLVC.