高压大电流坡印亭矢量原理功率变送器

POYNTING VECTOR BASED TRANSDUCER TO MEASURE HIGH VOLTAGE AND CURRENT IN POWER TRANSMISSION

高压大电流传统的测量方法是应用互感器将被测量降低到一个适当的数值,然后再利用电工仪器仪表测量。然而,由于互感器铁心的副作用,测量结果不可避免地存在死区和相角非线性误差。文中分析实现了一种新型的测量高压、大电流的功率变送器,该变送器基于坡印亭矢量原理,无铁心,还可用于测量高压配送线有功和无功功率,替代传统的互感器,可以避免互感器固有的相角非线性误差,并具有重量轻、成本低等优点。同时开发的变送器信号的二次测量装置,解决了微弱信号放大、参数计算和过程显示问题。

Ferrous core transformer (FCT) is traditionally used for measuring high voltage and current. It transforms the high value into a proper level of value suitable for attachment of electronic meters. However, the ferrous core distinctly causes the blind area, angle and nonlinear errors to the measurement result. To overcome the above mentioned disadvantages, this paper analyzes and proposes a novel transducer to measure high voltage and current in power transmission. It employs a single unit and is based on Poynting' s theorem, which defines the rate of flow of electromagnetic energy in terms of the electric and magnetic field intensities at a point in space. Current is measured by sensing the tangential component of the magnetic field, and voltage is evaluated by sensing the radial component of the electric field in a well-defined region around the high voltage conductor. Moreover, the developed equipment has the merits of light weight and low cost. An instrument is also developed to measure signals from the transducer, where the electric power and its factor are also calculated and displayed.