Grounding protection switch of transformer neutral point

Abstract

The invention discloses a grounding protection switch of a transformer neutral point. The switch is composed of an incoming wire insulated terminal and an outgoing wire insulated terminal; the incoming wire insulated terminal is connected with an upper copper bar; the outgoing wire insulated terminal is connected with a lower copper bar; and the upper copper bar and the lower bar are connected tothe upper end and the lower end of a switch core assembly. The switch core assembly consists of an operating mechanism, a driving assembly connected to the operating mechanism, and a vacuum arc-extinguishing chamber connected to the driving assembly; and the lower copper bar is connected to the lower end of the vacuum arc-extinguishing chamber. A transformer neutral point is connected with a ground conductor through the incoming insulated terminal and the outgoing insulated terminal of the switch to realize heavy-current effective grounding. Opening and closing are controlled by the switch core assembly.

Description

technical field [0001] The invention relates to the field of high-voltage power distribution equipment, in particular to a transformer neutral point grounding protection switch. Background technique [0002] The power system with a voltage level of 110kV and above in my country is an effective grounding system. The neutral point of some transformers is directly grounded. Not grounded. The neutral point of transformers currently in operation in my country usually adopts a graded insulation structure, which is characterized in that the insulation level of the neutral point is lower than the insulation level of the three-phase end outgoing line voltage level. In some power grids where the neutral point of the transformer is grounded, the ground short-circuit fault is a relatively common fault. When the system is struck by lightning or a ground fault occurs, and the neutral point grounded transformer trips, the power grid will become an ungrounded system. The rise of the sequen...

AI Technical Summary

Problems solved by technology

However, the currently used neutral point protection methods all have different defects: 1) For equipment that uses a separate gap protection, the gap between the horizontal rods used for discharge is exposed in the air, and is easily affected by factors such as humidity, pollution, electrical corrosion, or chemicals. The protection function is reduced or the effect is not good, the discharge dispersion is large, the power frequency freewheeling current is large, and the arc extinguishing ability is poor

2) The equipment protected by surge arresters alone cannot protect against power frequency overvoltage, and it needs to be protected under high power frequency overvoltage, and there is a risk of failure. In addition, regular power outages are required for preventive tests, and the maintenance workload is relatively large. and affect system reliability

3) The gap and the lightning arrester are used for protection, but during the operation of the power grid, affected by external or system factors, the system parameters are constantly changing, which increases the difficulty of matching the lightning arrester and the parallel gap

It increases the difficulty of design, and when the zero-sequence impedance of the transformer changes, the original reactor complete set may need to be replaced, which not only increases the workload, but also causes a waste of resources

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