Power distribution systems in developing countries have faced a phenomenal and rapid growth in the last two decades. While the losses in EHV network are generally about 4%-5%, bulk of the losses occur in the Sub-Transmission and Distribution system. We now discuss the main factors that contribute to high technical losses (Box).
Box : Factors Contributing to High Technical Losses
Box : Factors Contributing to High Technical Losses
- Weak and inadequate system due to low investments in the system.
- Large-scale rural electrification.
- Ad-hoc expansion of the system without scientific planning.
- Too many transformation stages.
- Low power factor.
- Low quality of equipment, poor construction and inadequate
- maintenance of equipment.
- Improper load management.
- Distribution transformers not located at Load centre.
Let us briefly discuss these factors.
Low Investments in T&D
The investment on T&D system in our country has generally been lower than that on generation. It is widely believed that the ideal ratio between the investment in generation to that in the distribution sector should be 1:1.However, the actual investment ratio has been. The low investment on T&D has generally led to the neglect of the distribution sector. The funds provided were mostly used for meeting normal development works which comprised giving new connections without adequate reinforcement needed thereof.
Large Scale Rural Electrification
Large scale rural electrification programme undertaken in the country resulted in long LT lines and extension of distribution network. This was done without strengthening the back up transmission and sub-transmission system. In practice, distribution lines were extended over long distances to feed loads scattered over large rural areas. This has resulted in high line resistance and, therefore, high I 2 R losses in the line.
Ad-hoc Expansion of the System without Scientific Planning
Distribution systems have been expanded on an adhoc and haphazard basis with the sole objective of giving connections without any scientific planning which has resulted in higher losses.
Too many Transformation Stages
In the Indian Distribution system, the energy is transformed to many intermediate stages before it reaches the consumer. Too many
transformation stages result in higher component of transformation losses.
Low Power Factor
Due to pumping load in rural areas, and air conditioners, coolers and industrial loads in urban areas, the system has a low power factor which results in higher losses. You know that for a given load, if the Power Factor is low, the current drawn is high. Consequently, the losses proportional to the square of the current will be higher.
Improper Load Management
Improper management of the load has led to over-loading of conductors and transformers in the system causing higher losses. Distribution Transformers not Located at Load Centre Often DTRs are not located centrally with respect to consumers.Consequently, the overall length of the distribution network increases and the farthest consumers obtain an extremely low voltage even though a reasonably good voltage level is maintained at the transformers’secondaries. This again leads to higher line losses.
Low Quality of Equipment, Poor Construction and Inadequate Maintenance of Equipment
Poor quality of equipment results in increased technical losses. For example, the distribution transformers are being manufactured with scrap steel resulting in substantially higher losses in transformation to distribution voltage. Poor workmanship contributes significantly towards increasing distribution losses. Joints are a source of power loss. Connections to the transformer bushing-stem, drop out fuse, isolator, and LT switch cause losses (Table ) . Moreover, poor construction results in increased losses. Poor workmanship leads to hot spots, equipment failure and interruption in supply. Deteriorated wires and services, which are not timely maintained, cause leakages and loss of power.
Low Investments in T&D
The investment on T&D system in our country has generally been lower than that on generation. It is widely believed that the ideal ratio between the investment in generation to that in the distribution sector should be 1:1.However, the actual investment ratio has been. The low investment on T&D has generally led to the neglect of the distribution sector. The funds provided were mostly used for meeting normal development works which comprised giving new connections without adequate reinforcement needed thereof.
Large Scale Rural Electrification
Large scale rural electrification programme undertaken in the country resulted in long LT lines and extension of distribution network. This was done without strengthening the back up transmission and sub-transmission system. In practice, distribution lines were extended over long distances to feed loads scattered over large rural areas. This has resulted in high line resistance and, therefore, high I 2 R losses in the line.
Ad-hoc Expansion of the System without Scientific Planning
Distribution systems have been expanded on an adhoc and haphazard basis with the sole objective of giving connections without any scientific planning which has resulted in higher losses.
Too many Transformation Stages
In the Indian Distribution system, the energy is transformed to many intermediate stages before it reaches the consumer. Too many
transformation stages result in higher component of transformation losses.
Low Power Factor
Due to pumping load in rural areas, and air conditioners, coolers and industrial loads in urban areas, the system has a low power factor which results in higher losses. You know that for a given load, if the Power Factor is low, the current drawn is high. Consequently, the losses proportional to the square of the current will be higher.
Improper Load Management
Improper management of the load has led to over-loading of conductors and transformers in the system causing higher losses. Distribution Transformers not Located at Load Centre Often DTRs are not located centrally with respect to consumers.Consequently, the overall length of the distribution network increases and the farthest consumers obtain an extremely low voltage even though a reasonably good voltage level is maintained at the transformers’secondaries. This again leads to higher line losses.
Low Quality of Equipment, Poor Construction and Inadequate Maintenance of Equipment
Poor quality of equipment results in increased technical losses. For example, the distribution transformers are being manufactured with scrap steel resulting in substantially higher losses in transformation to distribution voltage. Poor workmanship contributes significantly towards increasing distribution losses. Joints are a source of power loss. Connections to the transformer bushing-stem, drop out fuse, isolator, and LT switch cause losses (Table ) . Moreover, poor construction results in increased losses. Poor workmanship leads to hot spots, equipment failure and interruption in supply. Deteriorated wires and services, which are not timely maintained, cause leakages and loss of power.
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