The ratio of primary line length to its concerned secondary distribution line length is one of the important factors that influence the performance of primary distribution. Over the years, large scale expansion of the urban system and rural electrification programme in 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 due to load growth.
As a result, 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 very large length of LT lines as compared to High Tension (HT) lines resulting in high LT/ HT ratios. The ratio of LT to HT lines in our country has been of the order of 3. This results in high losses and low voltages at the consumer end.
Impact of Increasing HT Lines
Increasing HT lines can help in reducing both line losses and voltage drops.
Reduction in Line Losses
In the low voltage distribution system, supply at low voltages with long LT lines using smaller conductor sizes causes high line losses. However, the loss in HV system for the distribution of the same power is less than 1% of the LV system. Hence, with HV system the total energy losses are considerably reduced.
Reduction in Voltage Drops
The voltage drop in LV lines is very high as the lines are long and have smaller conductor sizes. In HV distribution systems, the voltage drop for the distribution of same quantum of power is less than 1% as against that in low voltage distribution system. This ensures proper voltage profile at the consumer end.
All other parameters, like load factor, power factor, etc., remaining the same,the percentage losses in a system having higher LT/HT ratio will be higher than in a system having lower LT/HT ratio. A ratio of 1 to 1.2 would be very beneficial to power distribution. As this measure is a must to improve efficiency and voltage regulation of distribution, additional capital investment should not come in the way.With this discussion on the impact of increasing HT lines on reduction in line losses and voltage drops, we now end the unit and summarise its contents.
As a result, 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 very large length of LT lines as compared to High Tension (HT) lines resulting in high LT/ HT ratios. The ratio of LT to HT lines in our country has been of the order of 3. This results in high losses and low voltages at the consumer end.
Impact of Increasing HT Lines
Increasing HT lines can help in reducing both line losses and voltage drops.
Reduction in Line Losses
In the low voltage distribution system, supply at low voltages with long LT lines using smaller conductor sizes causes high line losses. However, the loss in HV system for the distribution of the same power is less than 1% of the LV system. Hence, with HV system the total energy losses are considerably reduced.
Reduction in Voltage Drops
The voltage drop in LV lines is very high as the lines are long and have smaller conductor sizes. In HV distribution systems, the voltage drop for the distribution of same quantum of power is less than 1% as against that in low voltage distribution system. This ensures proper voltage profile at the consumer end.
All other parameters, like load factor, power factor, etc., remaining the same,the percentage losses in a system having higher LT/HT ratio will be higher than in a system having lower LT/HT ratio. A ratio of 1 to 1.2 would be very beneficial to power distribution. As this measure is a must to improve efficiency and voltage regulation of distribution, additional capital investment should not come in the way.With this discussion on the impact of increasing HT lines on reduction in line losses and voltage drops, we now end the unit and summarise its contents.
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