The Distributed Intelligence Current Protection Scheme In Active Distribution Network

The power supply reliability of distribution network can be improved by the distributed electric resources connected,the outage loss of user can be reduced,but the characteristics of power flow is changed,resulting in the power supply and the load has a dual uncertainty in the distribution network.A large number of distributed electric resources connected may lead the current distribution network protection to operate incorrectly.As such,a new scheme of active distribution network is needed eagerly,to ensure the distribution network for protection in active distribution network operate correctly.This paper introduces the concept and definition of distributed electric resources and active distribution network.The impact of distributed power distribution network for current protection is analyzed by the typical distribution network.According to the characteristics of short circuit current in active distribution: the short circuit current provided by fault branch is larger.The closer to the fault point,the larger the short circuit current is provided by distributed electric resources.The intelligence current protection scheme is based on fault current characteristics.Current information on the local agent and neighborhood range is used in the scheme.The fault point is determined by fault location:First of all,the fault location is made between the two agent,then the point of failure is determined.The switch of both fault point sides is tripped in order to isolate fault segments.Finally,flow diagram of the scheme is given.According to the typical distribution networks,the simulation model of active distribution network is established,the correctness of the theoretical analysis is verified by Matlab/Simulink.The Multi-agent system is used for fault location and fault isolation.Compared with the existing protection scheme,the program is simple and isolate the fault section selectively in the case of non-directional element,to ensure the normal supply of non-fault section and improve the reliability of non-fault section effectively.Only the judgment result of agent is transmitted over the network in order to reduce the burden on the network and determine the fault section quickly.Due to the failure protection issues caused by the distributed power connected are resolved effectively in this scheme.