The availability of electricity is one of the key factors in our life today. The integrity of Power supply is determined by reliable operation and high availability of equipment. Today’s HV switchgear, especially GIS (Gas Insulated metal enclosed Switchgear) technology has a high level of in service performance and is built and tested according to international standards. The worldwide GIS experience of more than 30 years has contributed to reliable and safe energy supplies by low number of disturbances and the long lifetime of GIS installations.
The need to make better use of resources has forced the attention to the availability aspect, thus reduced maintenance and outage costs. These questions become mandatory as a result of transmission system growth leading to network extension and upgrade and/or system performance uprating.Maintenance cannot compensate poor quality. Better availability of the GIS is the result of proven quality products, design solutions, flexibility and variability of a modular system. Gas Insulated Switchgear (GIS) offer high reliability, safety and maintenance-free features in much smaller space compare to conventional switchgear.
Circuit breaker and its operating mechanism:
The circuit breaker is equipped with self-energy are extinguishing chambers. Part of the energy needed for breaking the current comes from the arc itself. Therefore, the energy needed to be provided by the operating mechanisms is reduced. The operating mechanisms are spring operating mechanisms imported from abroad.
Combined disconnecting switch/earthing switch and operating mechanism:
Three-phase ganged operation. Based on the rotary motion of the moving contacts, the combined disconnecting switch/earthing switch completes closing and opening operations when the operating conditions are satisfied.
Traditional epoxy resin cast current transformers are used and digital photoelectric current transformers can be used, too.
Electric PT’s and CT’s:
CT’s are installed at the bottoms of the HGIS buildings—-installed at zero potential points. Rogowski coils can be used fully realize outputting of digital signals and current acquisition and conversion do not need high voltage insulation.
PT’s are inside bushings and adopt the principle of capacitive voltage division. —SF6 gas insulated. Used for acquisition and transmission of feeble voltage signals.
Features: safe, economical, reliable and delicate.
The equipment is connected to the overhead line bus-bars through SF6 gas insulating bushings. Silicon rubber bushings and high strength porcelain bushings can be used according to the users requirements.
After hot galvanization and painting, the supports are resistant to corrosion. They are designed to provide maximum bearing force and robustness, so the requirements for civil work are minimized
Reduced Maintenance Costs
Short Installation Time
Compact GIS substations offer the best solution when space available is limited, real estate prices are high, environmental conditions are more extreme ( for example, sand, wind, industrial pollution like cement and petrochemical plants or proximity to sea water) or maintenance labour costs are high.