基于振动传感的直流合成电场测量结构设计

Design of DC Composite Electric Field Measurement Structure Based on Vibratory Sensor

高压直流线路合成电场测量准确性对电磁环境评价具有重要影响,直接关系到相关工程的环保验收。目前最常用的合成场测量设备是旋转场磨式测试仪,其传感器采用快速转动的动片结构和碳刷接触接地的方式,在高速旋转时间歇性接触使得碳刷接地不可靠,离子在动片上积累引起测点附近的电场和离子流分布改变,使得测量结果与实际电场差异较大。为了解决现有接地方式和旋转结构存在的缺陷,在借鉴场磨的测量原理和结构布置的基础上,设计了水平往复运动式的合成场测量防磨损振动传感机构,提出了屏蔽片和感应片的尺寸和布置方式,推导了合成电场与感应电流的正弦关系,绘制了感应信号调制波形,分析了合成场与离子流场幅值、相位关系,通过风速测量条件限值确定了旋转电机运动转速为4800 r/min、振动频率80 Hz。研究结果表明:水平振动式结构静片接地消除了离子流的积累和畸变影响,微型滚珠导套连接可有效降低机械磨损,传感器具有良好的线性度,满足现场测量要求。

The measurement accuracy of the synthetic electric field of high-voltage DC lines has an important influence on the electromagnetic environment assessment,which is directly related to the environmental protection acceptance of related projects.At present,the most commonly used synthetic field measuring equipment is the rotating field mill tester,whose sensor adopts the structure of rapidly rotating rotor and the mode of carbon brush contacting and grounding.The intermittent contact during high-speed rotation makes the carbon brush grounding unreliable,and the ion accumulation on the rotor leads to the change of electric field and ion current distribution near the measuring point,thus making the measurement results quite different from the actual electric field.In order to solve the inherent defects of the existing grounding mode and rotating structure,based on the measuring principle and structural arrangement of field mill,this paper designs a horizontal reciprocating synthetic field measuring anti-wear vibration sensing mechanism,puts forward the size and arrangement of shielding and induction plates,deduces the sinusoidal relationship between the synthetic electric field and the induced current,draws the modulation waveform of the induced signal,analyzes the amplitude and phase relationship between the synthetic field and the ion flow field,and determines the rotating speed of the rotating motor to be 4800 r/min and frequency 80 Hz through the limit value of wind speed measurement condition.The results show that the stator plate grounding of the horizontal vibration structure eliminates the accumulation and distortion of ion current;the connection of micro ball guide sleeve can effectively reduce mechanical wear;and the sensor has good linearity,which can meet the requirements of field measurement.