On the Interplay between SVCs and Smart Inverters for Managing Voltage on Distribution Networks

Adoption of solar Photovoltaic (PV) is on the rise in different parts of the world. Till date, most solutions proposed to mitigate voltage problems caused by high PV penetration on distribution network have hovered around smart inverters. As new control technologies at the grid-edge such as Secondary VAr Controllers (SVCs) become ubiquitous, the need to understand the interplay between smart inverters and SVCs is felt. This paper addresses the interaction between smart inverters and SVCs through QSTS simulations. The field results collected from a pilot project performed at Hawaiian electric are taken as the basis for conducting these simulations and creating future scenarios. Using SVCs, Smart Inverters and optimized settings of the LTC, it is demonstrated that the PV hosting capacity of the distribution system can be doubled from (4.8MWPV to 9.6 MWPV) without causing voltage problems. Further, using a dynamic coordinated control of the LTC with SVCs, it is shown that the ramp rate of real power flow at the substation during evening time (duck curve effect) can be reduced by 10.8%. Finally, it is conjectured that the dynamic control of LTC can eliminate the need for extensive DER interconnection studies by naturally achieving optimized settings under varying operating conditions.