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The Research Of Distributed Network Protection Method With DG Based On The Transient Current Polarity Comparison

Posted on:2019-10-22Degree:MasterType:Thesis
Country:ChinaCandidate:P YaoFull Text:PDF
GTID:2392330605474174Subject:Power system and its automation
Abstract/Summary:PDF Full Text Request
With the number of grid-connected distributed power increasing,the traditional relay-protection is prone to mis-operate and mal-operate.As to this kind of distributed grid containing large number of DG,it is necessary to put forward a pretty reliable relay-protection method.Firstly,on the basis of summarizing the current protection method research status of the distributed grid containing DG,and analyzing the affection to the traditional distributional network protection of DG connecting,this paper proposed a pilot protection method based on the transient current polarity comparison to reduce the in-fluence to protection input signal from DG connecting.The reliability and correctness have been proved through simulating a dual power supply system.Then,this paper takeing the radiated distributed network containing DG as researching object,the wide area protection method of radiated distributed network containing DG based on the transient current polarity comparison has been proposed.This method improved the on-line calculation method for the adjacent relationship of key nodes based on matrix computation.According to the modified adjacent relation matix of key nodes obtained by this calculation method,this method builds fault imformation matrix combining with fault direction information at key node.And the fault area can be accurately identified through searching the fault information matrix.After determining the fault area,treating the pilot protection method based on the transient current polarity comparison as the criterion mentioned above,it can accurately determine the fault line among the fault area.And then circuit breaker operate to isolate the fault line.A typical radiated distributed network containing DG has been simulated and the calculating results have been analyzed,the results prove the reliability and the correctness of the protection method.Finally,the meshed distributed network containing DG being taken as researching object,a pilot protection method of meshed distributed network with DG based on the transient current polarity comparison is put forward.By setting transient current polarity detection points on both ends of all lines,the on-line caculation method of the adjacent relations of key nodes is improved to get the adjacent relationship of each detection point in the meshed network.Based on the adjacent relationship between detection points and transient current polarity at the detection point,according to the pilot protection method mentioned above,the fault location of ring distribution network containing DG can be accurately found.The reliability of the proposed protection method is verified by the simulation and results analysising of a typical ring distribution network containing DG.
Keywords/Search Tags:Distributed network containing DG, Transient current polarity, Wide area protection, Pilot protection
PDF Full Text Request
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