In a small current earthing system with neutral point ungrounded or grounded through resistance and arc suppression coil, due to the use of a large number of inductive and capacitive equipment and the existence of line to ground capacitance, when the system is single-phase grounded, the operation mode changes suddenly, and the system load has a large fluctuation, the PT winding voltage changes, which makes the excitation impedance of PT drop sharply. When the reactance and capacitive reactance are in the matching area, resonance occurs, In severe cases, it can cause PT explosions, causing accidents and directly threatening the safe operation of the power system.

        The device produced by our company uses 32-bit ARMCPUs as the core, and digital technology is used for harmonic elimination in the power grid. By utilizing ARM's fast and accurate data processing capabilities, Fourier analysis can be achieved, which can accurately distinguish single-phase grounding and harmonic faults and give an alarm. If it is resonance, the device will issue instructions to put the harmonic elimination circuit into operation, achieving rapid harmonic elimination. Through actual operation, it has been proven that the device accurately judges resonance, acts quickly, and perfectly solves the resonance problem of the power grid in the power system.

          This device is widely applicable to the power system of power plants, substations, and large factories and mining enterprises such as steel, coal, and petrochemical.