Abstract :
The paper discusses the problems of summation metering arising from the requirements of the 1926 Act, and it indicates the reasons which led to the choice of impulse instead of electrical summation on the larger equipments. For duplicate circuits the latter has been adopted as being simpler and less expensive. The types of meters installed were specially designed for grid metering purposes, and the accuracy obtained is an advance on previous requirements. The methods of impulse transmission and reception are described and compared, and it is shown that for uniform accuracy and performance ¿graded¿ impulsing is essential. The rate of impulsing has a decided effect on the life of the equipment and also on its accuracy. Considerable experience has already been gained in several of the grid districts, and the modifications which have been made to weak designs have resulted in consistent and accurate records. The large financial transactions dependent on the metering records make exacting demands on the equipments, and the number of operations performed annually necessitates constant and regular maintenance, for which a suitable programme is suggested. The number of faults to be expected on a satisfactory equipment is indicated, and it is shown that, although the majority of these are of a minor nature, delay in drawing up fault reports may result in the records being lost at a critical period.
