Repair of high voltage fuses

Usually high voltage fuses repair at the same time as the rest of the substation equipment and when significant defects are found requiring immediate removal.

Regular repairs of HV fuses begin with cleaning dust and dirt from support insulators with contacts and cartridge. Then in as a result of careful examination, the porcelain insulation is insured, and also reinforcement of brass caps on the ends of cartridges for high voltage fuses. Cracked support insulators and cartridges are replaced and broken reinforcement is restored.

Check the contact tightness of the contact surface brass caps or knives with spring contacts. If more tight wrapping, folding on pins and iron clamp. If the copper contact clamps have lost their elasticity due to overheating, the contacts must be replaced.

By pressing the protruding cylindrical trigger indicator fuse PKT, check the ease of its movement inside the cartridge and back.

A fuse whose operation indicator after repair does not find ease of movement, it is better to replace it. If there is no backup fuse, leave the previous one in operation, as the pointer defect cannot affect its breaking capacity.

In addition, the quality of the contact connection is checked. fuse with rail. Poor contact causes the terminal contact surface temperature of the cartridge, the fuse to exceed the allowable temperature and may cause the fuse to malfunction.

During the repair process, it is necessary to check the compliance of the nominal voltage and current of the fuse voltage and the maximum permissible overload current of the protected installation or network section.

The use of a PKT fuse with a rated voltage, high line voltage, when the fuse blows, it may cause overvoltage, which will be dangerous for the insulation of the protected installation fuses.

When using a fuse with a rated voltage lower than the mains voltage, its destruction may occur because there will be insufficient fuse length and the arc will not be extinguished.

A fuse with an incorrectly selected nominal current can cause false tripping or destruction of the protected installation.

During the repair process, it is necessary to adjust the nominal value of the fuses; rated current of transformers.

The design of fuses with quartz filler allows for repeated recharging, which is carried out by a qualified electrician in accordance with the factory fuse instructions.