With increasing distributed energy resources (DERs), both the power distribution and transmission systems are witnessing new challenges as well as opportunities. Voltage issues such as voltage rise and fluctuations (flicker) are becoming major concerns in the distribution network due to high penetration of intermittent solar PV. At the same time, solar PV devices with the volt/var control (VVC) capability are also opening up various opportunities for both the T&D systems. In this talk, we address the associated voltage challenges in the distribution systems as well as explore the potential opportunities for the transmission system in high PV penetration environment. The first part of the talk focuses on a local real-time adaptive VVC for distribution systems which dynamically adapts its parameters to ensure control stability and reliable performance in a wide range of external disturbances such as sudden cloud cover, cloud intermittency and substation voltage changes without much reliance on the feeder topology information. The second part of the talk investigates the impact of DER VVC on the bulk transmission grid. Our hypothesis is that, from the grid perspective, the numerous DER devices in volt/var control mode can be seen as geographically distributed var devices and because of their naturally distributed nature, they can provide more flexible volt/var support compared to costly conventional var devices. A transmission-distribution co-simulation platform is developed and used to verify the impact of DERs on the grid.
Ankit Singhal is a PhD student in Electrical Engineering at Iowa State University, USA. He received his B.Tech. from Indian Institute of Technology (IIT) Delhi, India in 2013. His research interests focus on enabling high penetration of DERs in the bulk grid via exploiting volt/var control capability of inverter based DERs. To achieve this, specific research problems include local volt/var control in distribution systems, impact of DERs on the grid operation and long-term voltage stability and transmission-distribution co-simulation platform