What is the effect of high gas pressure of sulfur hexafluoride circuit breaker?- SF6在线监测系统_SF6检漏仪_SF6传感器_SF6密度继电器

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What is the effect of high gas pressure of sulfur hexafluoride circuit breaker?

发布时间：2017-05-18 来源：ydlcb 浏览次数：170次

If the pressure of sulfur hexafluoride gas is too low, the insulation and arc extinguishing capacity of sulfur hexafluoride equipment will be reduced, if the pressure is too high, the mechanical life of the circuit breaker will be shortened, and the circuit breaker gas may be easy to liquefy, and the insulation and arc extinguishing capacity will be reduced, so it is generally necessary to charge according to the rated pressure of each gas chamber.

Sulfur hexafluoride circuit breaker has the characteristics of high fracture voltage, strong breaking capacity, allowing more continuous breaking times, low noise and no spark danger, and the circuit breaker is small in size, light in weight, large in capacity, and does not require maintenance or less maintenance. This makes it impossible for traditional oil circuit breakers and compressed air circuit breakers to be compared with them, so sulfur hexafluoride circuit breakers almost completely replace other types of circuit breakers in the field of ultra-high pressure.

The factors that affect the safe operation of sulfur hexafluoride equipment should be paid more attention because some of the effects are recessive and unforeseeable.

Weavers inspection technicians have summarized a number of situations in their work that can lead to low sulfur hexafluoride gas pressure. First check the sulfur hexafluoride gas pressure gauge pressure, and convert it to the ambient temperature at that time, if it is lower than the alarm pressure value, it is the sulfur hexafluoride SF6 gas leakage, otherwise the possibility of gas leakage can be ruled out.

The SF6 circuit breaker uses the SF6 gas density relay (gas temperature compensated pressure switch) to monitor changes in gas pressure. When the SF6 pressure drops to the first alarm value, the density relay operates and sends out the "SF6 pressure is low" signal, which should be processed as follows:

(1) Check the pressure gauge indication, check whether there is gas leakage, and determine whether the signal is correct. When SF6 gas is seriously leaking, if there is a stimulating smell and self-discomfort, measures should be taken to prevent poisoning.

(2) If there is no air leakage, but a drop in air pressure during long-term operation, it should be energized by professionals.

(3) If there is gas leakage phenomenon in the inspection, and when the SF6 gas pressure drops to the second alarm value, the density relay will operate, and the circuit breaker can not jump when the "closing trip lock" or "closing lock" or "opening lock" signal is reported, the circuit breaker should be applied to the dispatcher to stop the circuit breaker operation, and the following measures should be taken:

① Take off the operating safety and hang up the warning sign "No opening".

② Switch the faulty circuit breaker to the standby bus or bypass bus, and supply power through the bus circuit breaker or bypass circuit breaker.

③ Try to energize gas, can not energize gas, power off after load transfer.

④ Circuit breakers with serious air shortage can only be used as isolation switches. If the bus circuit breaker or bypass circuit breaker cannot replace the air circuit breaker, transfer the load, reduce the current of the air circuit breaker to zero, and then disconnect the circuit breaker

Sulfur hexafluoride gas leakage, check the record after recent gas filling, such as gas density decrease at a rate of greater than 0.01 mpa/year, must be detected with a leak detector, replace seals and other damaged parts. Specific method: If the leakage is very fast, it can be inflated to the rated pressure, check the pressure gauge, and use the leak detector to find the leak point of the pipeline joint, and you can also use the bandaging method to find the leak point one by one.

Sulfur hexafluoride (SF6) is a good gas insulator, and its typical applications are as dielectric insulation and arc suppression in high-voltage switchgear and enclosed combined electrical equipment in power supply systems. Once the sulfur hexafluoride gas dry test transformer body encounters high heat, high temperature (such as: arc), it will produce by-products such as hydrogen fluoride and sulfur dioxide gas, which coexist with the undecomposed sulfur hexafluoride gas, even in the case of trace inhalation can cause fatal damage to the human body. The rated pressure of SF6 high-voltage circuit breaker is generally 0.4 ~ 0.7MPa (gauge pressure), which usually refers to the pressure value when the ambient temperature is 20℃.