1.In the whole power development scenario, the Transmission and Distribution system constitutes the essential link among power generating sources and the ultimate consumers and substations and lines have to be erected for giving quality power supply.
2.The major equipment used in a substation comprises structures, circuit breakers, transformers, isolators, bus-bars, earthing switches, lightning arrestors, substation batteries, fire extinguishing equipment, etc. Overhead distribution lines and underground cables (in urban areas) hold power to the end-user.
3. There are two aspects of common maintenance: replacement of parts which are worn out from time to time and preventive maintenance for detecting deterioration and mal-operation of the system components. Periodic checks and tests should be carried as per specified procedures that might vary from utility to utility depending upon the site conditions.
4. Special hot line maintenance methods and tools are needed for managing live lines.
5. Because of increasing LT lines in the distribution system, losses, excessive voltage drops and frequent faults have resulted in the LT network leading to a higher rate of failure of distribution transformers. The high LT/HT ratios output in high losses and low voltages at the consumer end. An LT/HT ratio of 1 or 1.2 is preferable.