Application Of DC Resistance Method In Fault Location Of Power Cable Main Insulation

In recent years the production and application of power cable have been developing rapidly in China, and its safe operation will directly affect the safety and reliability of the power system. With the application of power cable, the failure probability of cable is higher,and quickly find and deal with cable feult have more and more influence on grid security.Firstly, this paper summarizes the cable feult detection research status at home and abroad, the existing methods of feult location and the basic knowledge of power cable, mainly introduces the travelling wave feult location technology and fault location method. On this basis, aiming at high-impedance ground and flashover feult of power cable, expounds a power cable main insulation fault location method based on DC resistance method. DC resistance method calculats the location of the fault by measuring the DC resistance of the fault point to the end of the cable and this method is not affected by contact resistance and the short circuit resistance, and the test precision is higher than other methods. In this paper, the implementation of the principle, operation process and matters need to pay attention to in the process of testing, all kinds of test environment conditions range of test conditions and results of measurement deviation are expounded in detail. Meanwhile, the good application of this method are introduced in high resistance ground feult and the flashover ground feult test. This paper also simply analyzes the traveling wave method and the traditional bridge method in the current situation of power cable fault test, especially the limitation in high resistance ground fault and the flashover ground fault test. At the same time, according to the author's actual work, the power cable fault types, causes and process of fault test and various kinds of distance measurement method is summarized briefly.Finally, detailed comparison of the DC resistance method with other kinds of commonly used test methods in the main insulation feult testing of the advantages and disadvantages, and through three actual case shows the DC resistance method to the application of the main insulation fault location. The DC resistance method studied in this paper can provide theory and practical guiding significance for cable fault location technology, the method can quickly and reliably test distance for partially breakdown fault of major insulation such as high resistance and the flashover ground fault, short the repair time, so as to improve power supply reliability.