An Online Monitoring Device for Twist Angle of Iced Single Conductor of Transmission Line

The real-time and accurate measurement of the twist angle of the overhead conductor during the icing period of the transmission line is of great significance to the monitoring and early warning of the icing state of the power grid. In order to obtain the twist degree of iced conductors in the natural environment, this article proposes an online monitoring device that is used to measure the twist degree of iced single conductor in real time. The device is mainly composed of four parts: data acquisition module, data processing & analysis module, data transmission module, and energy supply module. The data acquisition module takes the MPU-9250 chip as the core, combined with the high dynamic Kalman filter fusion algorithm, can accurately output the current attitude of the module in the form of 3-axis Euler angle. The data processing & analysis function is realized by embedding the data processing methods such as the direction cosine matrix (DCM) method, the noise reduction method based on modulus maxima reconstruction and the singularity detection method into the microcontroller unit (MCU). Meanwhile, the key parameters involved in the data processing process are discussed to guide the application in practical engineering. In terms of data transmission, Long Range Radio (LoRa) and General Packet Radio Service - fourth generation (GPRS-4G) modules are used to realize high and low frequency synchronous acquisition of personal computer (PC) and cloud server, respectively. Energy capture on the conductor is realized by combining double current transformer (CT) and some functional circuits such as protection, rectification, etc. Beside this, field test results show that the device proposed in this article can realize the measurement of twist angle signal with amplitude detection accuracy of 0.25° and cumulative amplitude error of less than 10%.