The financial health of most power distribution companies is in very bad shape. A reason for this the poor implementation of energy accounting and auditing measures.
Accounting and auditing in the electricity sector involves evolving procedures and checks to account for energy in the system, from generating stations down to the consumer level. In energy accounting system; each unit of electricity (kWh) is to be treated as a unit of electrical money.
The accounting system should ensure that the energy made available at sub-station/11kV feeder/distribution transformer, and the units used by consumers are cross-checked to see whether the difference between the two are within permissible limits. Also it should be ensured that energy billed and revenue realised tally. The prerequisites of energy audit can be divided into four parts: network documentation, consumer indexing / coding, proper metering, and effective methodology.
In any distribution network, the most important link is the 11 KV feeders which start from a sub-station, travels down the area and feeds to the consumers of that area through distribution transformers and LT (low tension) lines. Once the utilities can measure their losses at each point, then taking action is just a will of administration.
The methodology is very crucial for the accuracy of results in energy audit. Utilities should apply different methods instead of sticking to metered measuring of losses. For energy loss calculations, the network of distribution utility should be divided into two parts?HT (intake from Transco to DT) and LT. A ?Peak Constraint Multiple Load Flow? study to be done for both the HT & LT network for arriving at technical losses as the R/X ratio is quite high and loading of the feeders vary enormously. Metering demand will be taken from the consumers’ end to get the commercial/pilferage loss.
Ideally, energy audit should be carried out over smaller areas so that the areas suffering from high energy losses can be localised. This would however require providing a very large number of energy input meters at strategic points and checking the meters for high value consumers. Installing energy meter on all distribution feeders (at 11kV) in 33/11kV substation should be considered as an investment by utilities and distribution companies for protecting their revenue.
In some cases, use of certain technologies like aerial bunched cables in theft-prone areas and conversion of LT into HT lines i.e. less LT lines are suggested for reduction of commercial losses. Computerised billing of energy sales in a pilot area could be taken up to investigate the scope of loss reduction. Simultaneously, a plan can be prepared for liquidation of revenue areas from the data collected. The existing billing and revenue realisation system should also be evaluated for improving revenue collection efficiency.
The author is a professor at MDI, Gurgaon