Fault Location Technology Study For XLPE Power Cable

XLPE power cable is widespread availability because of its superiority insulationcapacity, with the focus on the characteristic of the XLPE insulation, it is necessary tostudy on the fault phenomenon and origin. Power cables are always used under theground, so it is difficult to find the fault location quickly after insulation malfunction,and so it is very important to find the fault location accurately, quickly andeconomically.Several new causes of failures are added in the XLPE power cable faultphenomenon analysis. Compared with the fault location methods home and abroad,this paper generalized merits, defects and applicability of them.Based on the global position system (GPS) and traveling-wave fault locationtheory, the method of gathering traveling-wave surge record data from both terminalsof the power cable is analyzed in this paper. Firstly, based on the characteristic of theXLPE insulation material, a two-terminal fault location mathematic model is deducedafter analysis the wave process of electromagnetic wave traveling in the power cable.After that, the electromagnetic-transient simulation software PSCAD/EMTDC isused to create two emulator models about no-load and terminal short circuit of XLPEcable. Change the parameters and length of the cable to see the alteration of theemulator wave. Based on it, create two-terminal fault location test models underthe circumstances of short circuit, low resistance, and high resistance. Differentparameters and fault points corresponding with different simulation waves, the faultlocation can be solved through analyzing them, and the characteristic and regularityof the electromagnetic wave traveling in the power cable is generalized. The paperemphatically analyzes the high resistance fault. Fault location software development is based on Visual Basic and the samplingdatabase files are stored by TXT file layout. The users can easily realize fault locationauto-calculation through concise software interface.By means of studying conclusions can been drawn as follows:1) The transfer rate of fault electromagnetic wave traveling in the power cable isrelated with insulation material not conductance radius;2) Fault transient traveling wave will reduce exponentially, the attenuation ofwave is direct ratio to the cable length and inverse ratio to the conductance radius;3) Compared with the conventional off-line positioning technology, two-terminalfault location technology can accurately locate the position for various fault types, theposition error is little, and blind area is eliminated;4) This fault location software can auto calculate these sampling data and givethe right results. Compared with the manual calculation results, fault location canbecome more accurate.