Transformer Core

The core balance current transformers are intended for providing earth leakage protection on 3 phase electrical system. These currents transformer are different from normal protective and metering current transformers due to their performance requirement. In insulated or compensated neutral networks, earth leakage currents Are small and generally very much less than the nominal load current. Such earth leakage current should not be allowed to exist for long periods of time, since eventually it leads to insulation failure on the healthy phases and subsequent development in phase to phase or double phase to earth faults. To protect cable circuits and also overhead transmission lines with cable terminations, core balance current transformers are commonly employed.