Research On Breaking Reasons And Preventive Methods Of10kV Voltage Transformer Fuse

The fuse used to protect voltage transformers (TV) blown and TV itself failuresoccur frequently in10kV distribution power network, and the problems is universal.Studying the cause of the fault and proposing appropriate measures, is of great practicalsignificance for the distribution system.Results reflect, that most of fault TV are bus bar TV, and the failure often happenswhen the single-phase earth fault disappears, or during arc grounding period. Thetransient process followed by single-phase grounding fault disappearance is detailedanalyzed, and come to a conclusion that electromagnetic oscillation (the ferromagneticresonance and low-frequency nonlinear oscillations) caused by capacity discharging isthe direct reason of the TV fuse blown.The characteristic of ferromagnetic resonance and low-frequency nonlinearoscillations is studied by a10kV distribution network model established by ATP-EMTP.Two factors which may influence the TV primary current, zero sequence loop dampingresistor and the disappearance moment of single-phase fault. are also researched by themathematical model.For the existing suppressing fuse blown measures, corresponding mathematicalsimulation models are established, their application background, principles, advantagesand disadvantages, and inhibitory effect are detailed analyzed. The primary neutral pointof TV grounded by harmonic eliminator is conserned the most practical measure bycomparing the economic and technical factors. At last, give some targeted suggestion forthe disadvantages of exiting suppressing measures.