INCREASING THE EFFICIENCY OF THE USE OF MEASURING TRANSFORMERS DURING ELECTRICITY METERING

Error limits of current and voltage measuring transformers are given and analyzed. The influence of factors on the accuracy of current and voltage measurement, as well as accounting of active and reactive electricity using current and voltage measuring transformers, was analyzed. In particular, for a measuring current transformer, such factors are the load schedule of the consumer, individual metrological characteristics of the transformer itself, as well as the load of its secondary winding (load). As for measuring voltage transformers, the accuracy of their operation is affected by the value of the load and individual metrological characteristics. It is emphasized that for the effective use of current and voltage measuring transformers at specific objects, it is necessary to conduct research in order to obtain initial information that will help to substantiate the specified efficiency: graphs of consumer loads, loads of secondary circuits, metrological characteristics. The analysis of the received information makes it possible to outline the most appropriate measures to increase the specified efficiency: optimization of the loading of the secondary circuits of the measuring transformers by, for example, choosing the optimal switching scheme, applying additional loads, as well as using measuring transformers of a higher accuracy class. An analysis of the results of the verification of voltage measuring transformers is given, which showed that the accuracy class of the indicated transformers corresponds to the values standardized by the state standard for loads from 25 to 100%, and in the case of a smaller or larger load, their error increases. In particular, with a smaller load, the error increases in the positive direction and reaches up to +0.5% per phase. The latter, in turn, leads to an increase in the measurement error of active or reactive energy in a threephase network of consumers up to +1.5%.