Gas-insulated substations based on Gas-insulated switchgears are designed to operate in a network with a voltage of 50 to 420 kV, both indoors and outdoors. The use of GIS switchgears allows to significantly reduce the areas and volumes occupied by the switchgear and provide the possibility of easier expansion of substations and circuit solutions compared to traditional switchgear.
By design, the Gas-insulated switchgears includes the main equipment of the substation, such as: Circuit breakers, Disconnectors with earthing switches, Measuring current transformers, Measuring voltage transformers, Surge Arresters , Busbars combined in a grounded metal case of a cylindrical or spherical shape filled with SF6 gas, which has the best insulating and arc-extinguishing properties.
According to the design, the switchgears can be with one or two busbar systems. Separate modules and elements allow the possibility of assembling the switchgear according to various electrical circuits. Gas-insulated switchgears consist of three poles with equipment placed in them, cable outlets, high-voltage inputs and control cabinets. The control cabinets contain equipment for signaling circuits, blocking, remote electrical control, control of SF6 gas pressure and its supply to the cell, supply of drives with compressed air.
GIS switchgears are designed to operate at gas-insulated transformer substations that can be implemented in electricity generation, transmission and distribution networks, at traction substations of railways, hard-to-reach facilities where it is required to reduce the substation area while implementing complex circuit solutions, at enterprises with high pollution of work electrical equipment, for the implementation of underground transformer substations.
Gas-insulated transformer substations are a good alternative to air-insulated transformer substations.