Research On Fault Type Identification Of Transmission Line

Transmission line faces variety of complex geographical environments and climateconditions because of its wide distribution into the wild. External changes from natural andenvironmental factors such as lightning, torrential rains, typhoons, animals and plants,floating hanging, cranes, etc., can cause transmission line faulty trip, and it directly affects thesafety of the line equipments and operation reliability of the grid. In order to reduce the rateof transmission line faulty trip, operation and maintenance departments must accuratelyidentify the type of fault, then take different measurements targeted on different types offaults. Currently, the identification of the type of transmission line faults is still in theexploratory stage nationally. The practical applications of the result is not satisfactory, andmost of researches are focusing on the study of lightning fault identification. Only few ofthem are studying the identification between lightning and non-lightning faults.Based on the cause of the faulty line and the research methodologies, the transmissionline fault types have been reclassified and are divided into two major categories, which arelightning and non-lightning. Wave propagation and attenuation circuit was simulated onfaulty lines, and the best installation distance is proposed for line wave monitoring device.This dissertation uses the ATP-EMPT electromagnetic transient simulation software platform,establishes a typical JMarti x line model for variety of fault simulations on different voltagelevels of transmission lines. Simulated faults include lightning and non-lightning strike,counter-around, high resistance and metal to ground failure and etc. Moreover, in-depthanalysis of the different characteristics of various faulty current transient simulation has beenperformed. Then this dissertation further proposes a methodology to distinguish differentfailure types among lightning fault and non-lightning fault, fielding failure and counter-attack,high resistance and metal to ground failure. Meanwhile, electromagnetic transientcharacteristics on induced lightning and direct lightning have been roughly analysed, and itsidentification methodology has been proposed.Finally, based on the distributed transmission line ripple waveform positioning device,fault waveform recording system and years of accumulated faulty ripple waveform data, thisdissertation concludes that the proposed fault identification methodology satisfies the typical fault identification requirements on transmission line trip with high accuracy according to thetype of fault identification based on the proposed typical fault trip identification, withreferencing to the search results from on-site operation and maintenance unit.