Technical losses: i) Copper losses ii) Unbalance loading iii) Long length of distribution lines iv) Conductor of inadequate size v) Various losses in transformer vi) Long distance between transformer and load center vii) Low power factor viii) Load factor ix) Reactive power x) Improper joints and connection
i) Copper losses: Copper loss is a major aspect in which all the real power of the distribution system is lost. As Pcu= I2R change in value of current will contribute more loss. Skin effect will also cause copper loss. ii) Unbalance loading: If any phases are more heavily loaded as compared to other ones, losses would definitely be higher than it would have been if lines were loaded evenly. Balancing line currents in distribution system may lead to considerable loss saving. iii) Long length of distribution lines: In rural areas loads are scattered over large areas causing extension of distribution lines. Hence primary and secondary distribution network spreads over long distances. Resistance varies directly with length and resistivity and inversely with cross sectional area. So for the same magnitude of line current longer line will have more losses than shorter. iv) Conductors of Inadequate Size: Scattered loads of distribution systems are fed by radial feeders which generally features inappropriate size of conductors. Conductor of smaller size will cause more losses than conductor of larger size. v) Losses in Transformer: Various losses in transformer such as Copper losses, Core losses will contribute more. Copper losses are due to I 2R losses are due to winding resistances and current flowing the windings. The core losses are due to eddy current and hysteresis loss. vi)Long distance between transformer and load center: Generally transformers are located far away from the consumers instead of any suitable center location. Though secondary voltage is maintained properly, consumer which is far away receives very low voltages at his end. vii) Low power factor: In primary and secondary distribution system power factor may be observed as low as 0.65 to 0.75. If power factor is low, current drawn is high for the given load. Hence lower the power factor higher the current and higher the losses associated with square of the current. viii)Load factor: Power consumption of consumers varies over different timings of day as well as seasons. Peak power consumption differs varies with category of consumers. Load factor is a measure of load variation and ranges from 0 to 1. More the demand variation over the feeder, lower the load factor and higher the energy loss. viii)Reactive Power: Reactive power is the part of the power, which is not utilized by the consumer. It is taken during switching on and fed back to the supply when switched off. Reactive power is caused by energy storage components, e.g. inductors, capacitors. ix)Improper joints and connections: Improper joints and connection ensures lose connections. If pressure between the connections is not properly maintained and not inspected time to time for the same, it leads to sparking and heating in contacts. Bad workmanship may be the season behind this which is due to less interest of the line men in their work.