Check Insulator and metal circular ring, clean or apply HVIC if necessary.
Note: Never open a secondary winding of a CT while on service.
Check primary and secondary connectors and conduct necessary tightening.
Visual Inspection to check oil level and defects or possible oil leaks.
Check all screwed joints & contact for tight fit.
Inspect the intermediate voltage transformer and check the minimum permissible oil level.
Inspect the voltage divider to be sure that no oil leak or serious accumulation of soot, dust or salt composite is present.
Carry-out the maintenance of operating mechanism.
Clean insulators if necessary, when an excessive amount of dirt has accumulated.
Check all screwed joints for tight fit.
Check flexible connections of earthing switches.
Check disconnectors and earthing switches, joints and bearings of the operating linkages for deformed bearing points.
Clean contacts of disconnectors as well as earthing switches and apply electrical contact grease, if necessary.
Check heating resistor located at its control panel for proper functioning.
For ground wire, check or test the grounding system.
Check the physical condition of bus (cables or bars).
Check Insulator, clean or apply HVIC if necessary.
Visual Inspection & Examination of all wiring connectors.
Performance such that no system disturbances are introduced by its operation. A valve action automatically allowing surge to pass and then closing up so as not to permit power current to flow to the ground.ĥ. High resistive to flow of power current.ģ. Ability to remove the surge energy from the line in a min. An ideal arrester must therefore have the following properties:ġ. SURGE ARRESTOR – are devices used to provide the necessary path to ground for such surges, yet prevent any power current form following the surge. It is also important that the protective ground not be accidentally removed, that is why all the earthing switches, disconnect switches, and circuit breakers are all interlocked to each other and proper/correct sequencing must be followed. For safety reasons, it is important that ground disconnects and all associated connections have good contact and low resistance. It does this by completing a circuit path, thereby reducing the voltage difference between the equipment and its surroundings. It is intended to protect people working on the grounded equipment. EARTHING SWITCH – also known as ground disconnect, which is used to connects the equipment to a grid of electrical conductors buried in the earth on the station property.