Current-transformer summations

The paper deals with the summation metering of multifeeder supplies by paralleled current transformers, with special reference to the errors likely to result and to suggested means of obviating such errors. The theoretical aspect of the effect of an idle transformer in a pair which is laralleled is discussed in section(2). A method of anticipatin the errors by calculating is proposed. Sections (3) and (4) describe experiments made to ascertain the errors under working conditions and to demonstrate the efficac of one means of avoiding them, viz. by the use of interlaced but separate series coils in instruments. Test-results are given. The more genreal case4s of unequal load sharing, both at uniform and at diverse power factors, are considered in Sections (5), (6), (7) and (8), from a theroretical point of view, and experimentla test-resultxs are recorded. A special 8-feeder summation metering scheme is described in Section (9), showing the possibility of achieving such a summation very accurately by comparaticvely simple means. Section (10) contains a description of a special mumetal summation transformer used in this scheme, and Sections (11) and (12) give test-results showing th eperfection of its perofrmance characteristics.