Length of LT Lines and Ratio of  HT & LT

The ratio of primary line length to its concerned secondary distribution line length is one of the significant factors in which influence the performance of primary distribution. Over the years, large scale expansion of the urban system and rural electrification program within the country has resulted in considerable expansion of Low Tension (LT) distribution network. The size of the distribution transformers has been constantly increasing to meet the increasing demand because of load growth.

Conclude, the length of LT lines/circuits is also increasing resulting in high losses in LT lines, excessive voltage drops, frequent faults on LT network and higher rate of failure of distribution transformers. This has also resulted in extremely large length of LT lines as compared to High Tension (HT) lines resulting in high LT/ HT ratios. A ratio of LT to HT lines in our country has been of the order of 3. This output in high losses and low voltages at the consumer end.