Hexafluoride sulphur circuit breaker with heating protecting equipment

Abstract

The invention discloses a sulphur hexafluoride breaker having a heating protection device and capable of normally working in the outdoor circumstance having low temperature (below minus 30 DEG C). The breaker is provided with an insulating sealing shell (1) in which an upper insulating pull rod (2), a lower insulating pull rod (3) and an upper contact (4), a lower contact (5) respectively fixed at front ends of the insulating pull rod (2) and the lower insulating pull rod (3) are provided; a temperature sensing element (7) and an electrothermal element (8) are provided below a lateral insulating board (6) which is provided below the lower contact (5); bottom panel of the insulating sealing shell (1) is provided with a temperature sensing element binding post (9) connected with the temperature sensing element (7) and an electrothermal element binding post (10) connected with the electrothermal element (8); the temperature sensing element binding post (9) and the electrothermal element binding post (10) are connected with a temperature control circuit provided outside the insulating sealing shell (1).

Description

Technical field: [0001] The invention relates to a sulfur hexafluoride circuit breaker, in particular to a sulfur hexafluoride circuit breaker which can work normally in an outdoor low temperature (below -30°C) environment and has a heating protection device. Background technique: [0002] High-voltage AC SF6 circuit breakers have been widely used in the power industry and are necessary high-voltage breaking products for large-scale substations. At present, the structure of the high-voltage AC SF6 circuit breaker is an insulating and sealed shell. In the insulating and sealed shell, there are upper and lower insulating pull rods connected to the terminals of the current transformer, and the front ends of the upper and lower insulating pull rods are There are high voltage contacts respectively. The lower insulating rod (contact) relies on other mechanical parts to contact and disconnect the upper insulating rod (contact), and completes the closing and opening of the high vol...

AI Technical Summary

Problems solved by technology

However, the pressure of sulfur hexafluoride is directly proportional to the temperature. When the ambient temperature is -37°C, the sulfur hexafluoride gas will be converted into a liquid state (the rated pressure in the insulating and sealed shell is 0.45Mpa), and its pressure is If it is reduced to 0.36MPa, the insulation strength will also be reduced due to insufficient pressure. At this time, the closing and opening operations may generate a large electric arc, which may cause explosions and other accidents.

At the same time, the normally open contact of the pressure gauge opens, blocking the trip circuit of the circuit breaker. If the line fails, the protection circuit starts and the circuit breaker cannot operate reliably, which will cause further expansion of the accident, resulting in protection leapfrog action or equipment damage accidents. occur

Therefore, the working environment temperature of the existing high-voltage AC sulfur hexafluoride circuit breaker is -30°C ~ +40°C, which not only limits the use in cold areas that are always lower than -30°C in winter, but also has problems due to sudden cooling (-30°C) ℃ below) the potential safety hazards

[0004] However, since the contacts in the insulating and sealed housing are charged at a high voltage of 10 to 220Kv and there are strict requirements on the sealing against gas leakage, there is no technical solution to the problem so far.

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