Algorithms for computing and programming transformer loss constants in solid-state meters

Many utilities use wholesale points of delivery or utility intertie metering involving metering applications on transformer buses. With utility deregulation on the horizon, cogenerators are becoming more common in the electric utility business. As in the case of joint utility interties, many cogeneration installations involve metering on a transformer bus. One utility usually owns the transformer while another utility or cogeneration installation transmits or receives power through the transformer. Installation costs are usually reduced by metering on low side transformer buses. Transformer losses were approximated and billed in the past through use of transformer loss curves, electromechanical transformer loss meters (with adjustable resistor panels) loss compensators, or by applying fixed percentages to demand and energy metered on the low voltage side of transformer buses. Current generations of solid-state meters offer flexible transformer loss compensation algorithms programmed into the meter register. These solid-state meters offer an alternative method for computing transformer losses that can be billed directly to the utility or cogenerator transmitting or receiving power. This paper summarizes some of the preliminary calculations used in the transformer loss algorithms. The paper further explores the features and benefits of the emerging meter technologies which provide features for compensating transformer losses