Practical electricity distribution system loss reduction

Noel P. Tobin and Mark Lyons, Electricity Supply Board, Ireland

Keywords

Abstract

Network losses represent a major cost in the delivery of electrical energy. As such they need to be caretilly managed. Sheer economics and environmental concerns compel a major focus of attention on any such waste of energy. A clear and accurate policy on loss evaluation and costing is required to ensure that limited capital resources are used to best advantage across the total power system. Distribution loss reduction is in many cases cheaper than committing generation plant and fuel to supplying losses over the life of a network. Distribution loss reduction requires a wide range of measures. These are grouped and discussed under the following headings.

OPERATIONS : Optimal sectionalising of networks or balancing of loads across feeders is one of the cheapest measures for reducing losses. This can be a complicated exercise, but simple formulae can be used to realise most of the benefits.

DESIGN : Economic sizing of conductors is of major importance in loss reduction and in our experience is the key design related issue. Capitalisation of transformer losses at purchase is also important.

MAJOR DEVELOPMENT PROJECTS : These target the most problematic networks. Additional expenditure beyond what might traditionally have been considered can produce improved loss efficiency. Voltage conversion from 1OkV to ZOkV is yielding major loss reduction in our medium voltage networks. Clear economic guidelines are required to optimise benefits

NETWORK REINFORCEMENT : In our experience about two thirds of feeder losses arise in the tirst third of main feeder lengths. Re-conductoring such sections can be extremely cost effective.