Design and Optimization of Magnetic Shielding Structures for Current Measurement in Triangularly Arranged Conductors

Accurately measuring the current is crucial for assessing the operational status of the line. The tunnel transmission approach presents challenges due to its intricate line layout in limited space. Utilizing non-contact current measurement offers a superior alternative. To suppress the potential magnetic interference in the transmission tunnel, a novel M-shaped magnetic shielding design for current measurement is proposed. The structure is used to measure current in triangularly arranged conductors where magnetic interference exists at random position. First, a one-dimensional and two-dimensional sensor system based on a triangular arrangement of conductors are used to analyze the magnetic field. Then, the structure of the magnetic shielding is derived. The relationship between the geometrical parameters of shielding structure and the position of the sensors with mean shielding uncertainty (MSU) is discussed by finite element analysis (FEA) method. At current of 2000 A in the conductors, the lowest MSU for the M-shape shielding structure (0.19%) is significantly lower than the lowest MSU for the C-shape shielding (1.63%). Moreover, the M-shaped shielding fits better with the geometry of conductors. In addition, thickness of the shielding structure, position of shielding structure and position of sensors are optimized based on the Non-dominated Sorting Genetic Algorithm-II (NSGA-II). The FEA method is used to simulate magnetic field interference acting on a three-phase AC current with an amplitude of 2000A. The two-dimensional sensor system with shielding structure can reduce the root mean square error (RMSE) of current to be measured from 14.42% to 3.79%.