What are the characteristics of sulfur hexafluoride circuit breakers?- 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 are the characteristics of sulfur hexafluoride circuit breakers?

发布时间：2017-05-18 来源：ydlcb 浏览次数：43次

1. Strong breaking ability

Sulfur hexafluoride circuit breaker is by blowing SF6 gas to complete the arc blowing, it has fast arc blowing speed, short arc burning time and large breaking current, which can effectively protect the safety of medium and high voltage circuits. Sulfur hexafluoride circuit breakers do not have the risk of reignition and reignition after disconnecting the capacitor or inductive current.

2, long electrical life

The sulfur hexafluoride circuit breaker has a long service life, a long maintenance cycle, and can adapt to frequent operation in a short period of time, and has good safety and durability. The sulfur hexafluoride circuit breaker can be continuously broken 19 times at a full capacity of 50kA, and the disconnecting current accumulates to 4200kA.

3, high insulation level

Sulfur hexafluoride circuit breaker is the use of sulfur hexafluoride gas as an insulating medium, the insulation level of this gas is very high, at 0.3MPa pressure, can easily pass a variety of insulation experiments, and has a large margin.

4, good sealing performance

The sulfur hexafluoride circuit breaker has the advantages of simple structure, good sealing, independent gas compartment, resistor and pillar, and low water content of sulfur hexafluoride itself. The installation and maintenance of sulfur hexafluoride circuit breaker is convenient, and the internal structure of the circuit breaker does not need to be opened, and the good internal tightness of sulfur hexafluoride circuit breaker can be maintained.

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. However, while recognizing the advantages of sulfur hexafluoride circuit breaker itself, it should also be clearly aware of the factors affecting the safe operation of sulfur hexafluoride equipment, because some of the effects are recessive and unforeseeable, it should be paid more attention to.

① Porcelain column structure: take building block type, strong series, can be used for multiple of the same unit arc extinguishing chamber and pillar porcelain jacket to form different voltage levels of circuit breakers. China FA4-550 type SF6 circuit breaker for porcelain post structure, its rated voltage of 500 kV, the maximum operating voltage of 550 kV. The circuit breaker consists of three independent single-phase and a hydraulic and electrical control cabinet. Each phase consists of four arc-extinguishing chambers (fractures) connected in series by two pillar porcelain sleeves. At the top of each pillar porcelain sleeve, two unit arc-extinguishers are arranged in a V-shape with an Angle of 120°, and two parallel capacitors are arranged horizontally. This structural arrangement takes into account both the mechanical stress state of the structure and the insulation requirements. Both the interrupter chamber and the pillar porcelain sleeve are filled with SF6 gas at rated pressure. Porcelain post circuit breakers use hydraulic operating mechanisms. The control and operating elements and circuits of the hydraulic mechanism are located in the control cabinet. The lower part of each phase circuit breaker is equipped with a set of hydraulic mechanism power components, such as hydraulic working cylinder. The extinguishing chamber is operated directly by the hydraulic working cylinder. The ceramic sleeve of the pillar is equipped with an insulated operating rod, which is connected with the hydraulic working cylinder.

② Tank structure: Using the advantages of box-type multi-oil circuit breaker, the circuit breaker and transformer installed together, compact structure, earthquake resistance and anti-pollution ability is strong, but the series is poor. The single phase structure of China LW-220 tank SF6 circuit breaker is shown in the figure. This type of circuit breaker is three-phase separate assembly type. The single phase consists of a base, an insulating porcelain bushing, a current transformer and a shell with a single break interrupter. Each has a hydraulic mechanism and a control cabinet, which can be operated separately and can be operated in three phases by electrical control. The circuit breaker adopts the bidirectional longitudinal blowing interrupter. When opening, the cylinder and the moving contact are driven by the transmission mechanism of the crank arm box. The extinguishing chamber is filled with SF6 gas rated at 6 gauge pressure (20 ° C).

Blocking effect

Give full play to the arc blowing effect of the gas flow, the arc extinguishing chamber is small in size, simple in structure, large in breaking current, short in arc burning time, no re-burning or no re-burning of the opening and breaking capacitor or inductor current, and low in overvoltage.

Long electrical life

50kA full capacity continuous breaking up to 19 times, the cumulative breaking current up to 4200kA, long maintenance cycle, suitable for frequent operation.

High insulation level

Sulfur hexafluoride gas at 0.3MPa pressure has passed various insulation tests and has a large margin. After the cumulative breaking current of 3000kA, each fracture can also withstand the power frequency voltage of 250kV for 1 min under 0.3MPa pressure, and the sulfur hexafluoride gas can still withstand the power frequency voltage of 166.4kV5min when reduced to zero gauge pressure.

Good sealing performance

Sulfur hexafluoride gas has low water content; The arc extinguishing chamber, resistor and pillar are divided into independent gas spacers, which do not need to be opened during field installation, and are connected with automatic connectors after installation; Easy installation and maintenance, and can prevent dirt and moisture into the circuit breaker.

Self-protection and monitoring system is complete

The signal cylinder in the hydraulic mechanism can realize self-protection of the circuit breaker: there is a density relay to monitor sulfur hexafluoride gas leakage; There are pressure switches and safety valves to monitor the pressure of hydraulic mechanism and protect the safety of hydraulic system. The hydraulic mechanism adopts a valve system that can prevent "slow pressure loss", and the mechanism can be locked on the body to ensure safe operation. Two sets of opening electromagnets and anti-jump protection are used in the control loop to ensure accurate operation.

Small operating power, smooth buffer

The transmission ratio between the working cylinder of the mechanism and the arc-extinguishing moving contact is 1:1, and the mechanism characteristics are stable. The characteristic stability of the mechanism can reach 3000 times, the research test of the mechanism life can reach 10000 times, and the operating noise is less than 90dB.