Zhongguo dianli (Nov 2023)
Design of DC Composite Electric Field Measurement Structure Based on Vibratory Sensor
Abstract
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 4 800 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.
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