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Role of Geographical Information Systems in distribution management
Vijay Kumar, Anjuli Chandra
Central Electricity Authority, New Delhi
Introduction
Sub- Transmission and Distribution systems constitute the link between electricity utilities and consumers, their revenue realization segment. For consumers, it represents the face of the utility. Efficient functioning of this segment of the utility is essential to sustain the growth of power sector and the economy. However, the present situation is characterised by unacceptably high losses (both technical and commercial), poor quality and reliability of supply, billing, revenue collection, frequent interruptions in supply and resultant consumer dis-satisfaction, etc. In this context, ST and segment of power sector needs immediate attention and action to achieve a turn around and self-sustenance of power sector.
Problems in Distribution Systems
The main issue in Distribution systems or rather more appropriately the issue confronting the power sector as a whole, is the reduction of Transmission & Distribution (T & D) losses to acceptable minimum levels. The all-India T & D losses, which were about 15% till 1966-67, increased gradually and are not at 24.79% (1997-98). During the last few years some of utilities variously estimated the losses in the range over 30% to 50% much higher than the preceding years. T & D losses in developed countries are around 7-8% only. Taking into consideration the Indian conditions such as far-flung rural areas, nature of loads, system configuration etc. the reasonable permissible (technical) energy losses should be 10%-15% in different states.
While the losses in Extra High Voltage (EHV) network are about 4%-5%, bulk of the losses occur in ST & D system. It is well known that these losses in Distribution systems include non-technical or commercial losses and that of power by various users with or without connivance of utility staff. These constitute a large component of overall losses. There are also losses on account of defective (slow) meters, stuck up/burnt meters etc. Further on account of estimation involved in agriculture sector consumption (30% of total), absence of adequate metering at the system level, deficiencies in consumer metering the validity of figure of T & D losses being reported become questionable. General conclusions are that the reported losses are under estimated and cover up large commercial losses (theft), actual figures are higher, technical losses are also high and bulk of the losses occur in Sub-Transmission and Distribution systems. Inefficiency, frequent interruptions, flickers and poor voltage also characterize distribution systems. In addition the billing and revenue collections are very poor leading to combined state utility financial losses of Rs. 26,0000 crores every year. If the current trend continues, in another three years, state utility financial losses will reach Rs. 45,000 crores a year. It is, therefore, necessary to bring about improvements in planning implementation and operation of ST & D systems in a scientific and efficient manner. The present traditional reactive and ad-hoc approach to network development should be replaced by an approach based on technical and reliability requirements, economic considerations of costs of energy loss and expansion of system to meet the growth of prospective demand with least cost.