Content area
Full text
Introduction
As an important energy, electric energy is transmitted from remote power stations to users by traditional power transmission systems (PTSs) that are generally composed of many distributed electrical substations (ESs) and power transmission lines. However, the power transmission lines are vulnerable. They usually suffer faults because of heavy loads, human damage, equipment damage, and natural disasters. These faults may cause large area blackouts. Battery energy storage systems1 can be installed at ESs for load leveling and relay protection.2 If faults occur in ESs, their battery energy storage systems can continually supply electric power for their output. Nevertheless, the electric power supply is temporary because the capacities of battery energy storage systems are limited. Therefore, the faults should be detected and restored urgently.
Smart grids are safe and reliable power systems, which usually are constructed by coalescing distributed control systems (DCSs) into traditional PTSs.3 Faults occurring in traditional PTSs should be detected and restored by DCSs. Therefore, reliable and safe DCSs are extreme importance for fault detection and restoration in smart grids.
Expert control systems can be used to play the roles of DCSs for fault detection and restoration in traditional PTSs. Minakawa et al.4 present a fault diagnosis expert system for electric power systems. Chien et al.5 propose a Bayesian network for fault diagnosis on distribution feeders based on expert knowledge. Ma et al.6 construct a multi-back propagation expert system to implement fault diagnosis in power systems. In these methods, the faulty states of power systems can be detected according to the knowledge of their proposed expert systems. The expert knowledge is updated and optimized by learning system information. However, the system information may also be interfered because of fault occurrences. Furthermore, the reliability and security of expert control systems may also be affected.
Multi-agent methods have high function reconfigurable characteristics, which can be used to implement DCSs. Momoh7 designs a control system based on multi-agent methods to perform fault detection and restoration for a navy ship system. Xu and Liu8 propose a multi-agent architecture to implement fault restoration in micro-grids. Each bus in a micro-grid is assigned with a node agent. Tong et al.9 present a DCS with a fault restoration algorithm. The...