Cybersecurity Risk Assessment for California's Smart Inverter Functions

The increased proliferation of Distributed Energy Resources (DERs) has made a new approach to distribution system planning necessary. California's Rule 21 stipulates the requirements for connecting generators to the distribution grid. Power electronics are instrumental in making these interconnections possible, converting electric power and energy into several forms and magnitudes. Power electronics also facilitate the control of distributed generation and storage assets. Inverters are prominent power electronics found in many customer premises because of their pertinence in converting electricity from DC to AC. Smart inverters go beyond basic conversion and have the potential to support the utility system. The additional grid support function creates some cyber security vulnerabilities, especially when the grid relies on inverter-dependent DER in high proliferation areas. In California., the Smart Inverter Working Group (SIWG) provided smart inverter functionality recommendations in three interrelated and interdependent phases. Both phase 1 and phase 3 functions are expected to comply with phase 2 communications requirements. This paper explores the risks associated with all phases of the SIWG Smart Inverter functions. We will consider current industry standards applicable to smart inverter communications such as the IEEE 2030.5 Implementation Guide for Smart Inverters.