PCB Rogowski Coils for 300 kA Current Measurement on a Multi-Split Conductor

Abstract

In this paper, a measuring system based on printed circuit board (PCB) Rogowski coils is introduced for high current measurement with a multi-conductor structure. A high current up to 300 kA is split into 16 branches to fulfill engineering requirements. This high current and multi-split structure bring about many problems into the measurement. Traditional current transformers (TCTs) are not suitable for this situation since they are saturated by these high currents. Series of PCB-based Rogowski coils are used in the presented system, which can measure this high current easily with high accuracy (<0.5% at Hz). To ensure high accuracy, the measuring system needs to have high uniformity and strong anti-interference ability. Uniformity is analyzed and the relevant formula is proposed to calculate it. Anti-interference ability is mainly related to the adjacent coil’s mutual inductance (ACMI), which is analyzed carefully to find variables affect it. Uniformity analysis and anti-interference ability analysis provide a theoretical basis for parameter design. This paper elaborates on parameter design and gives the basis for selecting each parameter, which could be used as a reference for peers. Besides, supporting circuits and frequency analysis are also given to guarantee the integrity of the measuring system. Finally, experiments are carried out to prove high uniformity and anti-interference ability of the measuring system, thus ensuring high measurement accuracy. The tests show that the measurement error can be repressed under 0.5%.