| In the isolated neutral system of medium voltage distribution network, when single-phase earth fault occurs, the bus-bar potential transformators(TV) may cause the TV primary high-voltage fuse fusing, which will affect the measured value of the watt-hour meter and Lead to false action of protection, etc. Even in some serious situation it may cause TV explosion, making power grid unsafe and unstable. It not only affect the power supply to users, but also cause the damage of main equipment. Based on the ferromagnetic resonance of ATP- EMTP simulation model and parameters, using ATPDraw to set up the simulation circuit and to calculate, the ferromagnetic resonance and low frequency non-liner oscillation caused by the normal operation, beginning and disappearing of single-phase earth fault are simulated in this article. Several resonance elimination measures are stimulated, and the results are compared. This paper proposed the measure that installing resonance elimination resistor and zero sequence TV at high-voltage neutral Point of TV can not only eliminate ferromagnetic resonance but also weaken the impulse current caused by capacitor discharging when fault disappears. Therefore the effectiveness of the fusing inhibition measure is demonstrated in this paper, power supply departments to solve similar problems provides a reference model of technology. |
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