Description:

ZF27-800 GIS, developed independently by company for controling, measuring, protecting and transforming the electric transmission line, consists of circuit breaker, current transformer, disconnector, earthing switch, main busbar, bushing and surge arrester, etc. The interrupter of circuit breaker is designed as double-break structure, and the hydraulic operating mechanism avoids the oil leak and slow-opening at zero pressure.

With rated current of 5000A and rated short-circuit breaking current of 50kA, this kind of GIS have been adopted in Substation GuanTing of 750kV power transmission project in Northwest China.

Main Features:

•  All the hydraulic pipelines are set inside to avoid the leakage, which is domestic initiate.
  

•  High current carrying performance with the rated current of 5000A.
  

• Excellent insulating level has achieved the high standard of DL/T593-2006.
  

• High mechanical endurance and reliability.
  

Technical Parameters:

What is the breaking and closing principle of gas-insulated switchgear?

Opening and Closing Principles:

• The circuit breaker is the key component in GIS for interrupting and closing circuits. When the circuit breaker receives an opening command, the operating mechanism rapidly separates the moving contact from the stationary contact, creating an arc between them. At this point, the high temperature of the arc causes the SF₆ gas to decompose rapidly, producing a large number of positive and negative ions and free electrons. These charged particles interact with the charged particles in the arc, reducing the concentration of conductive particles in the arc, increasing the arc resistance, and absorbing the energy of the arc. This process causes the arc to cool and extinguish quickly, thereby interrupting the circuit current.

• During the closing process, the operating mechanism moves the moving contact rapidly towards the stationary contact, ensuring reliable contact at the appropriate moment to complete the circuit connection. It is crucial to ensure that during the closing instant, no excessive inrush current or arc is generated.