Analysis and Effective Measures to Shorten Processing Time of Faults in Secondary Circuit

Abstract

The condition of secondary circuit directly determines whether mechanism box can be electrically operated, and qualification of the maintenance of the whole equipment depends on whether electric operation is in place and meets the requirements. Therefore, maintenance of the secondary circuit is the beginning and essential part of the whole maintenance. According to the index requirement, the processing time of fault in secondary circuit (T) and number of faults (N) should meet T≤7N-2(N≥1)and generally the time of secondary circuit maintenance should be no more than 10% of the entire maintenance time. Present Situation Investigation The complicated cables used in secondary circuit are prone to lead to frequent faults in the mechanism box of electrical equipment and the restored cable lines in the mechanism box become more confusing, resulting in unnecessary troubles for fault detection. Meanwhile, wrong contacts may be connected in the wiring process and it may directly leads to faults of no-phase or reverse phase, etc., imposing a risk for the stability of power system and sometimes even directly affecting the transmission time, resulting in both economic and reputation losses. According to investigations, reasons for faults or inefficient maintenance in secondary circuit are mainly lack of professional training, absence of professional wiring tools, small volume of mechanism box itself, inconsistent manufacturers of replaced cable with the original one, nonmatching attachments from the manufacturers and bad weather, etc.. In the collection of statistics on the maintenance process of each mechanism box with faults, since the cable lines in the mechanism box is complicated with small components and the close contacts make it easily to find out wrong contacts or fault connects between adjacent contacts leading to loose contacts, it can be dealt for one time from fault checking, processing to test operation. The probability of no repeated checking and processing is around 70%, which is not too high but can be improved. As found in experiments, if the mechanism box with the same fault has a neat wiring, processing time of faults can be greatly reduced, it is easier to detect the contact position and cable routing, and even those faults needing wire changing can be processed easily and with a high success rate. Therefore, although it is inevitable to cause faults by the multiple cables and complicated wiring in the mechanism box, poor quality of the cable itself, bad environment and temperature changes, etc., due to the long lasting maintenance time of wiring problems, low maintenance quality and efficiency can be improved and even avoided.