The Experiences of Decentralized Self-Healing Grid

This paper describes the experiences of deploying distribution ring network self-healing control system in China, including the architecture designing, retrofitting with advanced controller, simulating and testing on site.This decentralized self-healing system consists of nine sets of edging controllers Easergy T300 installed on 20kV feeders. These modular-designed T300s are fully integrated into ring main unit (RMU) switches. It is important specially for existing RMU upgrading that extra space is not needed.These controllers are connected using peer to peer (P2P) communication to build an autonomous system. The principle of the self-healing grid automation system is to start an automatic sequence of re-energizing the healthy part of the MV ring after a short circuit or earth fault somewhere in the ring. The re-energizing operations have to be performed in a minimum time with a maximum of safety and security. No distribution management system (DMS) is required and no operator intervention is needed.To validate this decentralized self-healing system, there are two steps: in the lab, special test bench can verify the whole system which is almost same as a real system just except communication network; on site, a dedicated simulator can be used to "generate" a short circuit fault, then switches are operated automatically according to self-healing algorithm in the real communication network.The project was implemented for State Grid Corporation of China. The main objectives of this program are to improve the feeder automation capability and enhance reliability of power supply in the CBD area of Hangzhou. This self-healing control system help our utility customer to achieve their goals.