Factors of Contributing to Losses in Service Cables
1. Tapping of underground service cables: The service cables must be visible so that tapping of cables can be detected. Underground service cables should be avoided as they are not visible for routine inspection.
2. Size of the cable: Improper selection of cable size results in increased losses and lower voltage at the consumer premises leading to revenue loss.
3. Bimetallic connections: Generally, the LT conductor is of aluminium while at many places the service cable is of copper. Connecting aluminium and copper creates a bi-metallic junction leading to corrosion, high resistance and failure. This should be avoided.
4. Connections: A Loose connections of the service cables can result in sparking and is another source of avoidable energy loss.
5. Guarding against Losses due to High Impedance Faults: The high impedance faults result in avoidable technical loss and may also cause safety hazards in overhead system. High impedance faults are often caused due to trees touching the lines and bird nesting, etc. Regular line patrolling, tree trimming and removing bird nests are needed to prevent such faults.
In underground cables high impedance faults may occur due to insulation pitting, breakdowns from digging, rodent infestation or ageing of cable insulation, formation of carbon trees, etc. Locating and repairing underground faults requires specialized equipment and training.