Current Transformer Performance under High Voltage Cable Related Transients

The subject of the research in this paper is the behavior of current transformers (CT) in 110 kV power networks under the influence of the "zero missing" phenomenon, specific for cable lines, and more precisely the saturation of their magnetic core. The study was conducted by simulations of electromagnetic transients in ATP-EMTP, where a model of a compensated HV cable line is presented. Different scenarios with different degrees of reactive power compensation have been studied. The conditions under which zero-missing phenomenon occurs are considered. The influence of the transients on the secondary current of the current transformers and the operation of relay protection is analyzed.