Energy audit of a 400/220 kV substation - A case study

The paper highlights the necessity of undertaking performance analysis and energy audit study of an electrical installation, more particularly a power substation on regular basis. A 630 MVA, 400/220 kV substation was identified and a detailed study was carried out to assess the various station performance parameters under different operating conditions. It was observed that the installed capacity of the station (transformer) was very large compared to the actual load it had to supply. Thus the station was under loaded and underutilized for the major period of its operation. This reduced the operational efficiency of the station. Secondly the incoming line voltage level was remaining high during most of the period of operation. Presently voltage is tried to be maintained by switching ON the line reactors at the receiving and sending ends of this station, switching OFF one of the 400 kV incoming lines during off peak loading conditions, thus risking the supply reliability. The present study emphasizes on the urgent need for improving the power quality, streamlining and optimizing the station capacity, operations and its loading pattern. Accordingly suggestions are proposed for the same.