Huang Rujin, Zhang Wenbin, Zhu Junyu, Zou Xiangqi, Wu Hetao, Suo Chunguang
College of Science, Kunming University of Science and Technology, Kunming 650504, China.
College of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming 650504, China.
Sensors (Basel). 2023 Aug 14;23(16):7161. doi: 10.3390/s23167161.
The accurate voltage measurement of distribution networks is of great significance in power dispatching and fault diagnosis. Voltage sensors based on the spatial electric field effect do not require grounding, which provides the possibility for the distributed measurement of transmission line voltages. However, the divider ratio of suspension grounding voltage sensors is affected by the height between the sensor and the ground, as well as the distance between the sensor and the telegraph pole. In this paper, a self-calibration method based on internal capacitance transformation is proposed to realize the on-line calibration of suspension grounding voltage sensors. The calibration is accomplished by switching different parameters in the conditioning circuit, and the calibration process does not require power failure or known input excitation. In addition, the impact of electric fields in the other two phases of three-phase transmission lines on measurement through simulation research is quantified in this paper. In order to reduce the impact of interference electric fields, an equipotential shielding structure is designed. The circuit topology and probe prototype have been developed and testing has been conducted in laboratory conditions; the experimental results show that the maximum relative error of voltage amplitude is 1.65%, and the phase relative error is 0.94%. The measurement accuracy is not limited by the height to ground or the distance to the telegraph pole. In addition, in the application of an equipotential shielding probe, the maximum deviation of measured voltage is 0.7% with and without interference electric fields.
配电网的精确电压测量在电力调度和故障诊断中具有重要意义。基于空间电场效应的电压传感器无需接地，这为输电线路电压的分布式测量提供了可能。然而，悬挂式接地电压传感器的分压比受传感器与地面之间的高度以及传感器与电线杆之间的距离影响。本文提出一种基于内部电容变换的自校准方法，以实现悬挂式接地电压传感器的在线校准。该校准通过切换调节电路中的不同参数来完成，校准过程无需停电或已知输入激励。此外，本文通过仿真研究量化了三相输电线路另外两相中的电场对测量的影响。为降低干扰电场的影响，设计了一种等电位屏蔽结构。开发了电路拓扑和探头原型，并在实验室条件下进行了测试；实验结果表明，电压幅值的最大相对误差为1.65%，相位相对误差为0.94%。测量精度不受离地高度或与电线杆距离的限制。此外，在等电位屏蔽探头的应用中，有无干扰电场时测量电压的最大偏差为0.7%。
