In the modern age, Power bas become a major essential commodity after air, food, clothing and shelter, which play a major role for development of country.
Hence, maintenance of Transmission line plays an important role in achieving minimum interruption, which results in not only revenue earnings for the organization, but also for major industrial growth and development of the country at large. Thus ensuring Power system stability and stable power supply, which calls for preventive maintenance of transmission lines(EHT lines) and Sub-stations.
The Technique adopted to maintain transmission lines, by working on it when it is live is known as Hot Line Technique. This technique is also used to maintain the ODS of Sub-stations.
The advantages of working in Hot Line technique over the convectional method.
HOT STICK METHOD: In this method the line men will be at ground potential and works with epoxy glass Hot Sticks and always safe clearance is maintained between mechanic and live potential. The Hot sticks used in this technique generally 12feet long and is made up of epoxy glass fibre having a insulation strength of 100 KV per foot and these are moisture resistant. The other hardware used along with Hot sticks is made up of high strength light weight alluminium alloy.
BARE HAND TECHNIQUE: This technique is based on the principle of Faradays cage theory. According to the theory no potential difference exists within a metal cage that has been charged to the same potential of conductor with respect to ground. There are no electrical charges and electric field inside with respect to ground. With no potential difference there will not be any flow of current.
COMBINATION METHOD: In this method both Hot stick and bare hand method are clubbed together for carrying out the Hot Line Works to overcome the constraints in the tower top arrangement.
The transmission tower cannot be designed to withstand natural calamities like storms, earthquake etc. due to resources and economy.
Breakdown of transmission line attended with conventional method required time of 6 to 8 weeks, which is time consuming. To overcome this problem is the use of emergency restoration system .
Light in weight, Foundation not required, less inventory, standardized and modular design, critical towers can be by passed very easily.