Eesearch Of The Zhongxin Guangzhou Knowledge City In20kV Protection

Zhongxin Knowledge city of Guangzhou will Set up20kV power distribution system,relay protection configuration principle and the Setting calculation is one of the integratedtechnology to establish20kV medium voltage distribution network process, It has the verybig relations with neutral point grounding way, relevant equipment selection and investmentbudget, power supply reliability and so on. According to the domestic20kV of mediumvoltage distribution network operating experience, and combining the20kV system actualcondition to choice the reasonable neutral point grounding way and the correspondingprotection measures. In this paper the subject research as following contents:1.To establish the distribution automation structure of Zhongxin knowledge city20kVdistribution network. To analysis the20kV distribution operation advantages and necessity,and20kV protection characteristics, from grade sequence, connection mode and groundingmethod to introduce the distribution automation structure of20kV distribution network.2.To study the knowledge city20kV system protection configuration and the fixed valuesetting principles. Through the three relay protection device configuration schemecomparison, decided uses integrated terminal in situ protection, control scheme. To analyzeand study on the line protection, busbar protection, failure protection, feeder protection,distribution transformer protection, and fixed value setting principles for the rules, includingline over-current protection setting principle, line zero sequence current protection settingprinciple, longitudinal differential protection setting principle, transformer primary protectionsetting principle, bus and circuit breaker failure protection setting principle, as well as toconsiderate the treatment with system operating mode changes.3.To analysis the backup protection optimal fit. Introduced the significance of backupprotection, and backup protection matching principle; Analysis the optimization methodsamong backup protection of knowledge city, including transformer20kv side alternate withbackup protection,20kV line alternate with short circuit protection and substation maintransformer mothball protection and20kV side appear with protection optimization; Analysisof the backup protection and primary protection between the optimization methods, includingfixed value setting.4.To introduce the knowledge city20kV distribution network protectioncharacteristics,focuses on the key question-communication and time tick. Through the inputlongitudinal differential protection in fault distribution network to realize the reliablesubstation fault line selection and fault point location on the line. Based on the networkcommunication time tick methods security for protection system about reliable action andquick action. With longitudinal differential current protection as a criterion of fault lineselection method, which can realize accurate location for the single-phase earth fault offault resistance less than3000. This paper provides the relay protection systemprotection method in20kV distribution network under new flexible grounding system isfeasible.