A Simple and Generalized Model to Compute LT Distribution Loss and Testing of its Applicability

Abstract

The loss is the major problem for all electric utilities worldwide. Power loss occurs in all parts of the power system that include generation, transmission, and distribution loss. Most of the losses occur in the electricity distribution system. For the economic operation of the power system, these losses should be minimized by formulating and implementing proper loss reduction strategies and techniques. The electric utility can segregate losses, identify their priority, and may launch effective loss reduction strategies and techniques. Distribution feeder losses are grouped as technical loss (TL) and non-technical losses (NTL). The total loss of a LT feeder can be determined by knowing the total energy supplied by a transformer and the energy consumed by all consumers connected to that transformer. The difference between the total loss and technical loss is the non-technical loss and without knowing the TL NTL cannot be determined. But the determination of the TL of a LT feeder by simulation is tedious and time-consuming as the network of the LT line is complex and irregular. Therefore, some mathematical model shall be formulated which can help to determine the TL of the LT line in an easier and faster way. This research intends to find a simple and generalized model to compute LT distribution loss and testing of its applicability. This research is based on the real field data of certain parts of the Balaju Distribution Center, Nepal Electricity Authority (NEA). Five different distribution feeders of the urban area and five different distribution feeders of the rural area are taken for the analysis. Losses for those distribution feeders are found after load flow analysis on ETAP. Similarly, losses for the same distribution feeders are found using uniformly distributed load (UDL) and uniformly varying load (UVL) concepts and compared with ETAP simulation results. The study shows that, for the urban area, losses obtained from ETAP simulation and UDL concept are nearly equal with a maximum error of 3.86% while that of ETAP and UVL concept is not equal as there is a maximum variation of 51.32%. Similarly, for the rural areas, losses obtained from ETAP simulation and UDL concept are not equal with a maximum error of 26.83% and that of ETAP and UVL concept is also not equal as there is a maximum variation of 23.01%. Thus, the study shows that the losses of rural area LT feeders cannot be computed using either UDL or UVL concept but the losses of urban area LT feeders can be computed using the UDL concept with a maximum error of 3.86 %.