Research Of Improving Measure And Action Analysis For The Abnormal Run Relay In Power Network

This article basing on the concept of relay protection, the important role in power system, development and the hardware of micro-processor, elaborates the problems of relay protection existing in the power network operation.In the relay protection operation, because of defective design, abnormal unit and the failure of satisfying the special need of power network, it brings about the malfunction and rejecting operation of protective relaying equipment, which is a serious threat of the safe and stable operation for power network.Based the reality of relay protection and combined the exceptional action accidents of relay protection, from the aspect of the equipment theory, secondary circuit design and the stable operation, this article analyses the operating characteristic, finds the existing problems in the relay protection and advances improving measures, which have important directive meanings to the management of power network operation. the main work includes:(1) Research of unusual problems for re-close circuit in the rebuilding of substation transformerBased on the he rebuilding of substation transformer, the problems about multi-automatic re-close of breaker caused by energy shortage, automatic re-close of breaker caused by control circuit line-break or break-brake on the spot, as a result of defective design in the transforming of substation transformer, are deeply analyses, besides improving measures are put forward.(2) Research of improving the operation reliability for micro-processor automatic transfer switchingBased on the defects caused by the failure of blocking PT line-break, which is brought by the improper parameter settings of CSB-21A micro-processor automatic transfer switching, the measures that automatic transfer switching uses lowering the transformation ratio of current transducer and the measures of improving the operation reliability of automatic transfer switching in the lightly loaded substation transformer are put forward at the same time, paratactic circuit of voltage switching is improved and two-position relay is used,which raise the reliability of voltage switching.(3) Analysis of the 500kV circuit breaker's exceptional action. The detailed analysis of the action process of relay protection and record of accident wave is made, based on a failure of 500kV circuit breaker's automatic re-closure. The root causes of the automatic re-closing refuse failure are confirmed. The AC sampling plug-in replacement is changed and a technical prevention is proposed.(4) Analysis of the connecting method about transformer differential protectionBased on the theory of substation transformer differential protection, the operating characteristic of percentage differential protection and the different connecting method in the substation transformer is analysed. The differences about operating characteristic of percentage differential protection when current circuit is connected with devices by different methods are also analysed. The detailed analysis of False tripping accident of transformer differential protection is made,pointing out the defect of differential protection is caused by improper method connecting current circuit with differential protection when using inner bridge connection.The mode selection and design about the inner bridge protection devices of substantion transformer is proposed.