Tan Xiangyu, Zhang Wenbin, He Mingxing, Li Wenyun, Ao Gang, Zhou Fangrong
Electric Power Research Institute, Yunnan Power Grid Co., Ltd., Kunming 650217, China.
College of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming 650504, China.
Sensors (Basel). 2023 Oct 8;23(19):8316. doi: 10.3390/s23198316.
Non-contact voltage sensors based on the principle of electric field coupling have the advantages of simple loading and unloading, high construction safety, and the fact that they are not affected by line insulation. They can accurately measure line voltage without the need to connect to the measured object. Starting from the principle of non-contact voltage measurement, this article abstracts a non-contact voltage measurement model into the principle of capacitive voltage sharing and deduces its transfer relationship. Secondly, it is theoretically inferred that the edge effect of the traditional symmetric structure sensor plate will cause the actual capacitance value between the sensor plates to be greater than the theoretically calculated capacitance value, resulting in a certain measurement error. Therefore, the addition of an equipotential ring structure is proposed to eliminate the edge additional capacitance caused by the edge effect in order to design the sensor structure. In addition, due to the influence of sensor volume, material dielectric constant, and other factors, the capacitance value of the sensor itself is only at pF level, resulting in poor low-frequency performance and imbuing the sensor with a low voltage division ratio. In this regard, this article analyzes the measurement principle of non-contact voltage sensors. By paralleling ceramic capacitors between the two electrode plates of the sensor, the capacitance of the sensor itself is effectively increased, improving the low-frequency performance of the sensor while also increasing the sensor's voltage division ratio. In addition, by introducing a single pole double throw switch to switch parallel capacitors with different capacitance values, the sensor can have different voltage division ratios in different measurement scenarios, giving it a certain degree of adaptability. The final sensor prototype was made, and a high and low voltage experimental platform was built to test the sensor performance. The experimental results showed that the sensor has good linearity and high measurement accuracy, with a ratio error of within ±3%.
基于电场耦合原理的非接触式电压传感器具有装卸简便、施工安全性高以及不受线路绝缘影响的优点。它们无需连接被测对象就能准确测量线路电压。本文从非接触式电压测量原理出发，将非接触式电压测量模型抽象为电容分压原理并推导其传递关系。其次，从理论上推断传统对称结构传感板的边缘效应会导致传感板之间的实际电容值大于理论计算的电容值，从而产生一定的测量误差。因此，提出增加等电位环结构以消除边缘效应引起的边缘附加电容，进而设计传感器结构。此外，由于传感器体积、材料介电常数等因素的影响，传感器本身的电容值仅处于皮法级别，导致低频性能较差且传感器的分压比很低。对此，本文分析了非接触式电压传感器的测量原理。通过在传感器的两个电极板之间并联陶瓷电容，有效增大了传感器本身的电容，提高了传感器的低频性能，同时也提高了传感器的分压比。此外，通过引入单刀双掷开关来切换不同电容值的并联电容，传感器在不同测量场景下可具有不同的分压比，使其具有一定的适应性。制作了最终的传感器样机，并搭建了高低压实验平台来测试传感器性能。实验结果表明，该传感器具有良好的线性度和较高的测量精度，比值误差在±3%以内。
