A wireless sensor for nanosecond transient electric field measurement based on asymptotic conical antenna and high-speed data acquisition technology

The transient electromagnetic field generated by the operation of high-voltage switches in substations can cause electromagnetic interference to the communication and control electronic equipment in the substation. On the other hand, it can also reflect the working status of the high-voltage switch itself. Therefore, it is necessary to measure and study it. However, the laying of optical fibers and cables is not allowed in the substation. So, a wireless E-field sensor is developed in this paper for measuring the switching E-field pulse in substations. A monopole asymptotic conical antenna is designed as the transient E-field receiving antenna, which has better low-frequency response performance and higher sensitivity than ordinary electrically small antennas. The developed wireless sensor can perform analog-to-digital conversion on the signal received by the antenna at a sampling rate of 2 Gsps and then transmit the digitized switching E-field pulse signal to the host computer through 5G communication technology. The calibration results show that the wireless sensor has a measurement range of 0.1-10 kV/m and a measurement bandwidth of 180 Hz to 350 MHz. Moreover, the measurement range can be adjusted by adjusting the size of the antenna and the circuit parameters of the antenna matching circuit. In addition, based on the developed wireless sensor, the switching E-field pulse in a 330 kV substation is measured, and its time domain and frequency domain waveform characteristics are analyzed and summarized.