STRENGTHEN THE PROTECTION RELAY AND URGENCY CONTROL SYSTEMS TO IMPROVE THE CAPABILITY OF SECURITY IN THE INTERCONNECTED POWER NETWORK
ZHANG Bao-hui(School of Electrical Eengineering Xi'an Jiaotong Univeisity,Xi'an 710049,China)
In terms of the general policy of our country's power system developing, which is "power transmission from west China to east China, mutual supply between south and north, nationwide interconnection", this paper analyses the possible questions that may appear in the course of the implementation of this strategy. Such as the unfavorable impact of the fault occurring on the accurate work of the protection relay and the control device when AC and DC are transmitted in parallel, the further improvement of transmission capacity of the long-distance HV transmission line,the potential instability of system network structure as a result of the poor coordination of the performance sequence and the start-up threshold of the existing auto-mechanism,and the difficulties in preventing catastrophic accident with low possibility by means of power system stability control and ensuring that the accident will not be extended in the disconnected system with fixed disconnection.This paper presents that fourfold line of defence should be set up instead of threefold for security and stability control system, and points out the basic principles and the key techniques which is required to further research for developing the fourfold line of defence. These principles and techniques are introduced as follows. The first is to develop a new type of protection relay system with rapidity of action and better transient performance, including the research on the new type of protection relay useful to the transmission line inclusive of electronic apparatus, the new type of protection relay of 750kV system and the new theories of protection using transient component of the fault.The second is to research into power system transient stability prediction and urgency control systems independent of the system models and parameters (50277027).based on the information network of synchronous phasor to improve transmission capacity and to prevent synchronous instability, including the study on generator swing trajectory prediction based on the information of synchronous phasor measurement units, the expression of transient instability boundary and the principle of instability prediction, and realization techniques of transient stability real-time control system of the whole power system.Based on information network of wide area,the third is to construct a network protective system, which should coordinate the performance of back-up protection relays and other auto-mechanisms in the whole system network,to maintain the stability of the truss of network and prevent a unorderly trips,including the optimal cooperation of the protection relay of transmission line and auto-reclosure,the research on the protective relaying system with "transmission section",and the network protection based on multi-agent system.The fourth is to construct a self-adaptive network disconnection system to prevent the collapse of interconnection power system and shorten the duration of power cut, including the principle of fast identifying the mode of out-of-step generators,the automatic catching of oscillation center and the self-adaptive decision of network disconnection section.The fifth is to arouse the enthusiasm of participators in the power market for ensuring the security of power system, through studying the principle of taking on economic responsibility of the protection and urgency control system in Power Market.
【CateGory Index】： TM71
【CateGory Index】： TM71