Live line Insulator Washing

Many electric networks are located near sources extreme pollution. Pollutants such as chemicals, cement and salt may accumulate on insulators.
The contaminants when mixed with moisture in the air can significantly reduce the effectiveness of the power line insulators. If these contaminants are not removed from the insulators they will create dry bands also called conductive bands. These conductive bands enable leakage (also know as creepage) current to jump across the insulator dry band to dry band.
If enough time passes with cleaning, there will eventually be a dead short to earth call a flashover.
Flashovers are not good. Flashovers can impair the electric company's equipment and will produce a transient power blackout which means the consumer is out of power until the difficulty can be fixed.

These faults are usually brief in nature and will vary irregularly with no obvious pattern. This can be extremely frustrating to every person involved in trying to put and end to the problem.
In locations where there is inadequate natural precipitation to clean the insulators, other procedures must be used.
1. Hand washing - line is off
2. High pressure washing with water - dead line
3. High pressure cleaning using water- hot line
If the power company has enough capacity then they can choose to switch the power line off and clean by hand crews climb the structures and wash the insulators with cloths and or mild cleaning solutions to eliminate the pollutants) or using an insulator washing machine. However, often power companies do not have that alternative.
Power lines are very costly to build, so most utilities do not have extra a lot of excess capacity. They often have no choice but to wash the insulators energized.
Energized line Insulator washers use water. Normal potable water has impurities. These impurities may be conductive or non-conductive. If the impurities are conductive, the water is conductive.
There is an upper limit on the conductivity which is dependent upon the electrical potential. If the water's conductivity is above the upper threshold, then it cannot be used. In some locations, there is no accessible supply of non-conductive water. In these areas, the water borne contaminants must be removed using reverse osmosis.
The Live Line washing equipment is usually custom built to the end user's needs. Some power companies want their equipment fitted with an aerial bucket so that their linemen can wash from the platform.Often the platforms can reach to heights of over 200 feet!
Other electric utilities have the linemen climb the towers. They use washing equipment mounted on trailers and/or truck chassis. In locations where the land is mountainous, the Hot Line cleaning equipment, may be assembled (albeit a miniature adaptation of it) on helicopters . A lineman can clean from a platform mounted on the helicopter.

Find out more about Insulator Washers.