The Value of Smart Inverter Control in Distribution Energy Management Systems and Virtual Power Plants, and Opportunities for South Africa

Abstract

The rising penetration of distributed energy resources (DERs) in distribution networks can lead to various technical challenges, including poor power quality and system instability. To mitigate these challenges, distribution network operators and regulators are looking towards the coordinated control of smart inverter-based DERs to support the utility grid and provide additional services. Smart inverters have advanced grid supportive functions that assist the utility in maintaining power quality and stability. However, it is not practical for network operators to directly monitor and control each individual inverter and DER. As a result, distribution energy resource management systems (DERMS) and virtual power plants (VPPs) are being tested out in international states with high leading renewable energy penetration, such as Hawaii, Arizona, California and Victoria. DERMS and VPPs can aggregate and optimize the performance of various DERs through smart inverters. This paper investigates the characteristics and benefits of the existing coordinated control techniques of smart inverters as applied in contexts of high DER penetration internationally. The value of smart inverter coordinated control is presented through a literature review and international examples. Based on the review of international practice, recommendations for South Africa are made considering the local context regarding existing infrastructure and grid regulation restrictions, which affect the necessary communications protocol for coordinated control through a DERMS or VPP. The paper finds that VPPs or DERMS in South Africa are feasible, but with the relevant cybersecurity measures and technical regulations update for smart inverter functionality.