Establishing The Fault Tree Of Transmission Cable And Its Typical Fault Analysis

At present, the rapid development of China’s economy is continuing, China’s demand forelectricity will be increasing, power transmission system undertaking to transport power hasalso grown rapidly.the cable is laid in ground, which can make full use of land resources, anddoes not affect the appearance, not easy to be damaged by outer force, so the power cable hasbeen widely used in power transmission network in the city.In the normal environment,the life expectancy of XLPE power cable is20-30years.However, the cable is laid in cable trench or buried in the ground, contacts withsoil, water, moisture for long term, insulating is susceptible to corrode and permeate.Inaddition, local defects in the programe of cable and its accessories manufacturing orinstallation can cause the fault. Once fault of underground cable occurs, which is difficult tofind, not only waste a lot of manpower and resources, but also brings difficult to estimateoutage, resulting in serious economic losses and social impacts. Therefore, how to quicklyand effectively judge the running state of the cable, and take the necessary, appropriatetreatment methods according to the state, has an important practical significance on theprevention of power interruption.In this paper, using the fault tree analysis method of state assessment, which is asystematic method of deduction. It takes the event (top event) which is the last thing systemwants to happen as the analysis target, then find all the direct cause about every direct reason,sequentially,until the foundation of the direct causes (end events).Achieving with certainsymbols, expressing of the above relationship, to identify the logical relationship aboutvarious factors (end events) and system failure (top event), so study quantitatively the impactof the end event to the top event.End events includes possible failure within a systemcomponent, environment impact, software defacts, human error and so on. This paper aimedat the part of transmission cable, respectively on the fault of transmission cable, intermediatejoint body, grounding system to analysis and study, and to establish the corresponding faulttree about parts of transmission cable, then to analyze typical failure and propose specificoperation and maintenance recommendations. It establishes the foundation for transmissioncable fault statistics quantificationally and transmission cable state evaluation based on faulttree.