Laser Diode-in-Capacitors for High-Voltage Line Non-Contact Monitoring: Voltage, Electromagnetic Interference and Vibration Monitoring

Abstract

Power grid is an indispensable infrastructure in modern society, in order to ensure the normal operation of the grid, online non-contact monitoring of high-voltage lines is essential. In this work, a ‘capacitor–laser diode (LD)–capacitor’ structure, namely, laser diode in capacitors (LDIC), that can be used for non-contact monitoring of high-voltage (HV) line status by directly transferring the status information of the HV line to modulated laser pulses is proposed. The proposed LDIC can accurately extract the real-time voltage changes on the HV line with an accuracy level of 0.959%. Because the LDIC is sensitive to high-frequency electromagnetic field, the LDIC is successfully utilised to detect the external electromagnetic interference (EMI) to obtain the intensity and frequency of the external EMI. Additionally, the amplitude and frequency of the HV line vibration can be accurately monitored by using the LDIC. For the third-order curve fitting of vibration amplitude, the average error is only 0.00867, and the average error of linear fitting of vibration frequency is as low as 0.00655. This work provides a novel approach for the online monitoring of the HV line status and a new supplement for the development of power grid technology.