Aiming at the problem that the mixed use of overhead lines and cables causes serious refraction and attenuation of the traveling wave signal in propagation, which makes the traditional traveling wave sensor unable to adapt to the weak signal identification and recording requirements. A wideband sensor for detecting transient current signal of power system is developed. The detection principle of the anisotropic magnetoresistive sensor is analyzed, and the tiny signal precision differential amplifier circuit is designed. Based on the actual situation of the power system, a corresponding test environment was built to conduct transient current transfer tests. The experimental results show that the sensor has a high linearity in the 0-5MHz bandwidth, and is suitable for the extraction of various transient signals, especially in the power system traveling wave protection has high application value.

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In view of the fact that traditional traveling wave sensors need to be directly connected with primary high-voltage equipment, the layout is not flexible, construction is inconvenient, and the traditional ferromagnetic coil traveling wave sensors have problems such as low sensitivity and magnetic saturation. The use of magnetoresistance chip to design non-contact traveling wave sensor is proposed. Theoretical analysis of the magnetoresistance chip is carried out, and the tunnel magnetoresistance chip is selected as the non-contact sensor magnetic sensitive element; the non-contact sensor hardware circuit is designed, the sample is trial-produced, and the experimental test is carried out. The experiment shows that the non-contact sensor can detect a traveling wave signal with a bandwidth of 100kHz∼5MHz, which meets the requirements of traveling wave detection for common fault types in the distribution network. A demonstration project has been built, and operation shows that the non-contact sensor can successfully detect single-phase grounding, interphase short circuit, lightning strikes and other fault types traveling wave signal, sensitivity is higher than traditional traveling wave sensor, positioning error is less than 150m.