With the development of urban power grids, the proportion of cable lines has increased year by year, resulting in a sharp increase in capacitance current to ground. For the distribution network based on cable lines, if the neutral point is not grounded or the neutral point is operated by the arc suppression coil grounding method, when a single-phase ground fault occurs, several times the amplitude will be high. The voltage is easy to develop into a phase-to-phase short circuit, which causes the fault to expand, damages the electrical equipment, and jeopardizes the safe operation of the system. If the neutral point is grounded by a small resistor, the overvoltage multiple can be reduced to 2.5 times or less, so that it will not cause damage to electrical equipment, prolong the service life of the electrical equipment, and enable the relay protection equipment to operate reliably. Quickly remove the faulty line.
SMR-NGR series transformer neutral point grounding resistance cabinet standard equipment consists of grounding resistance element, supporting insulator, insulating sleeve, internal wiring and cabinet. It is suitable for transmission and distribution system with voltage level of 6 ~ 66kV for 50 / 60Hz. A current limiting protection device for connecting a neutral point of a transformer to the earth. When a neutral grounding resistance cabinet is installed, when a non-metallic grounding occurs, the current flowing through the grounding point and the neutral point is significantly lower than that of the metallic grounding, and the non-faulty phase voltage is also significantly reduced, and the finite current is depressurized. Avoid damage to the line and equipment. It is usually used for short-term work, regardless of the ability to pass large currents for long periods of time. Its power and voltage levels depend on the conditions of the transmission and distribution system.