A Novel Anti-DC Bias Energy Meter Based on Magnetic-Valve-Type Current Transformer

The direct current will cause the electromagnetic current transformer (CT) saturation, which will lead to the measurement error of some energy meters using CT for current sensing. This article presents a novel anti-dc bias energy meter. In the proposed approach, the magnetic-valve-type current transformer (MVCT) is used as the current sensor in the meter instead of conventional CT. As a result, the distorted secondary current can be fully compensated within MVCT when the core gets saturated. The principle of the new technology is described in detail. The simulations and experiments are performed to verify the correctness and feasibility of this novel energy meter when measuring load power consumption with dc bias.