Adaptive Power System Protective Relays Based on Multi-Agent System Combined with Conservative Power Theory for Highly penetrated Renewable Energy Resources

Inverter based resources (IBR) such as energy storage and renewable energy generators (REGs) are increasingly integrated into the grid. Typically, the fault current of IBRs are limited to 1.2 to 1.5 per unit. An over current relay designed for a synchronous generator will malfunction if the SG is replaced with an IBR. Thus, it is desirable to have an adaptive protection strategies to deal with various operating conditions due to different penetration level of REGs, topology configuration, and operation modes (grid-connected or islanded). Multiagent system (MAS) has been shown to have unique advantages for power system protection because agents operate autonomously and make decisions based on local information, which improves the speed and accuracy of fault detection. In this paper, we proposed to use MAS in combination with conservative power theory (CPT) for protection scheme to deal with IBR-dominated grid. Since CPT allows current to be decomposed into active, reactive, and void currents, it has better adaptedness in dealing with IBRs. We will show how to design an overcurrent relays and differential relays by means of MAS combined with CPT. The presented cases are some preliminary studies on how advanced power theory can be used to solve protection problems in the modern grid.