A Reliability Analysis Model And The Evaluation Research Of Relay Protection Of Intelligent Substation Based On Information Flow

With the development of the process-layer of intelligent substation, the relay-protectionis different from the traditional microcomputer protection, including the data collection, dataprocessing and data output. The opaque in the process of communication, the uncertainty ofcommunication delay and the non-uniqueness of the communication paths threaten thereliability of the relay protection, which has strictly demand in the security and the real-timeof information.The information flow of process-layer carries the sample data and the on-off state as wellas the trip and control demand. So the feature of the process-layer can be represented as thedistribution, real time and reliability of the information flow. The information-flow which isthe carrier of the feature of the process-layer, can reflect the operating characteristic of theprocess-layer to some extent. So, not only be limited to the physical level, the study of theprotection system of information network can be extended into the study of the informationflow quantify and the data qualitative, as well as the study of the reliability of the protectioncan be deep into the connectivity of the information flow.Therefore, choosing the information flow as the point-cut, analyze the feature of theinformation flow from the data’s special properties and the connectivity of theinformation-flow perspective, and then give the study of the whole communicationperformance. In order to improve the reliability of the process layer network, a new protectionmethod which is based on the information flow is presented. Based on the analysis of thefeature of the information flow, the formation mechanism of the abnormal information flow isstudied as well as the character of the fault diagnosis, and the related protection strategies arethen proposed. Furthermore, based on the packet analysis of GOOSE and SV, and theinformation flow monitoring, the protection criterion, protection logic and threshold settingcalculation are proposed.A communication reliability model of relay protection of intelligent substation based onthe information flow and an evaluate method are proposed. The reliability calculation modelof information flow and the mapping model between the sub-function of the relay protectionand the information flow are established. Make calculation of the relay protection reliability of QinYun intelligent substation, which realizes the reliability evaluation of relay protection.Furthermore, several centralized protections based on the information flow sharing areproposed, and two of them are studied on reliability. At last, the study results are compared,and the one which is best fit to the intelligent substation is pointed out.