Parametric Reconstruction of Multiple Line Currents Based on Magnetic Sensor Array

Current measurement is of great importance for the state monitoring and parameter identification in a power grid. This article proposed a contactless magnetic-based sensor array method for the acquisition of line current parameters, aiming at the measurement for arbitrary line currents. The inverse problem between the line current with arbitrary parameters and the magnetic field was introduced. Due to the nonlinearity of the inverse problem, a comprehensive algorithm consisting of metaheuristic algorithms and interior point method was employed. The influences of structural parameters on the calculation accuracy have been explicitly studied, indicating the optimal sensor array design parameters concerning the number of sensors, the distance between adjacent sensors, and the shape of sensor array. The sensor array was implemented by utilizing the dual-axial tunneling magnetoresistive (TMR) magnetic-field measurement device. In terms of the 2-D magnetic-field measurement results for two currents with all parameters unknown, the current magnitude error was 0.6%, proving the effectiveness of the comprehensive algorithm together with the annular sensor array. The proposed method for current measurement gives a promising solution for various line current measurement requirements in the power grid.