基于电场耦合原理和差分输入结构的电压传感器设计与实验

Design and Experiment of Voltage Transformer Based on Electric Field Coupling Principle and Differential Input Structure

传统的电压互感器存在体积大、绝缘困难、铁心饱和、铁磁谐振过电压、暂态响应特性差等问题。基于电场耦合原理和差分输入结构的电压传感器不需要与被测物体或地面接触,可以避免上述问题。然而,差分电极之间需要足够高的电容以获得足够的精度和高的分压比。现有的利用差动电极间互电容的方法存在许多问题,不能满足实际需要。针对上述问题,文中采用多层陶瓷电容器代替互电容,设计了一种新型的电压传感器。实验结果表明,该传感器具有良好的精度和瞬态响应特性。工频下的比值误差在±0.5%以内,相位差在1°以内。在500 Hz~30 kHz范围内的比值误差在±5%以内,相位差在5°以内。此外,它还具有成本低、小型化、外形灵活、分压比易于调整等优点。

Traditional potential transformers have such problems as large volume,difficulty in insulation,saturation of iron core,weak of ferroresonance overvoltage and transient response characteristics.The voltage transformer based on the principle of electric field coupling and differential input structure does not need to contact the tested object or the ground so to avoid above problems.However,sufficient high capacitance is needed between the differential electrodes so to obtain sufficient accuracy and a high voltage division ratio.The existing method of using mutual capacitance between the differential electrodes has many problems and can not meet the practical needs.To solve above problems,a kind of new type potential transformer by using multi-layer ceramic capacitor to replace the mutual capacitance is designed.The experimental results show that the transformer has excellent accuracy and transient response characteristics.The ratio error is within±0.5%and the phase error is within 1°under power frequency.And the ratio error is within±5%and the phase error is within 5°in the range of 500 Hz~30 k Hz.Moreover,it also has such advantages as low cost,miniaturization,flexible appearance and easy adjustment of voltage division ratio.