Applied Research Of Anti-maloperation System In Intelligent Substation

This paper studied automatic communication network in intelligent station and its reliability by the way of reliability block diagram analysis.First of all,the structure of automation communication network was studied.The structure was “three layers and two nets” and the basic function of the equipment,circuit structure and the logical structure of the automation communication network and the network mode of the process layer,spacer layer and station layer were analyzed.Secondly,it studied the reliability block diagram theory,which drew out the concept of minimal path.It adopted exponential distribution model to set the reliability model for network element.It put forward that automation communication system can be divided into relay protection communication network and automation monitoring communication network,and reliability block diagram model was set for the two child network.Again,it studied the method of calculating the reliability model,using the maximum likelihood estimation method to solve the network element`s exponential distribution parameter.Then it adopted the node traversal method based on the logical function to simplify the reliability block diagram of automation communication system and simplify reliability computing.Then it put forward the disjoint algorithm to improve calculation.Finally,it made an example analysis for a 220 kv line automation communication network and set a model for its components,transmission medium and network by maximum likelihood estimation algorithm to obtain network element`s the exponential distribution parameters.According to the physical topology structure,the network’s reliability block diagram model was established and the original reliability block diagram was simplified.The automation communication network was divided into two sub networks of relay protection and automation monitor.It fund the minimum path of two sub networks through the node traversal method based on the logic function.Then it analyzed the reliability of two sub diagrams,through the analysis the effectiveness of the proposed method was confirmed.