Water type arc extinguishing protection gap device for medium and low voltage distribution network

Abstract

The invention discloses a water type arc extinguishing clearance protection device for middle / low voltage distribution networks. When the water type arc extinguishing clearance protection device is used in thunderstorm weather, the lightning stroke trip-out rate and lightning line breakage rate of power transmission / distribution lines of middle / low-voltage AC / DC electric power systems can be reduced. The water type arc extinguishing clearance protection device is equipped between two ends of a power transmission / distribution insulator string in parallel, and can be broken down before the insulator string for introducing current of the lightning stroke to the ground. When power-frequency follow current passes, the length of an air main gap can be automatically increased, thereby elongating a freewheeling arc; and meanwhile, electronegative gas (water steam) is filled and injected in an added semi-closed gap, thereby greatly improving the overall insulation breakdown strength of the gap instantly. On the condition that recovery voltage is not changed, arc heat radiation is improved and insulation strength of the gap is increased greatly, and therefore arc is ensured to be extinguished. The water type arc extinguishing clearance protection device for middle / low voltage distribution networks comprises a parallel-connected grounding electrode, an insulation water column arc extinguisher, a thin water column arc injection channel, a parallel-connected conductor electrode and the air main gap. The water type arc extinguishing clearance protection device for middle / low voltage distribution networks has the advantages of low cost, simple installation and operation, capability of being broken down repeatedly, high durability, and no hidden trouble.

Description

technical field [0001] The invention relates to a protective gap for protecting insulator strings and wires from burning by short-circuit power-frequency freewheeling arcs, and in particular to a water vapor natural arc parallel gap device suitable for transmission and distribution lines of medium and low voltage power systems. Background technique [0002] Because the low-voltage distribution network is not an important load, its lightning trip rate and lightning accident rate have always been high. Low-voltage power grids such as 10kV distribution network insulated overhead conductors still have lightning strikes (direct lightning or induction lightning) Disconnect conclusion. However, with the continuous expansion of the short-circuit capacity of the power system and the area of ​​transmission and distribution lines, the trip rate and disconnection accident rate of lightning strikes (inductive lightning and direct lightning strikes) will become important indicators for po...

AI Technical Summary

Problems solved by technology

The problem is that there are many relatively backward distribution networks that do not have automatic reclosing devices installed. The failure of circuit breakers to trip is equivalent to permanent failures, which cause "blackout accidents" and affect the economic benefits of the power grid; at the same time, circuit breakers are loaded many times Tripping will also obviously affect its function and shorten its life. When the circuit breaker fails to move, it will cause more serious grid accidents

[0005] Therefore, in view of the lightning protection problem of the medium and low voltage distribution network, it is not advisable to install lightning arresters or parallel ordinary gaps, and there are considerable hidden dangers after installation.

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