一种基于瞬时无功功率的电能计量方法

针对目前非正弦不平衡条件下电能计量时不同谐波功率会正负抵消的现象,提出一种基于瞬时无功功率来计量相功率的电能计量方法。该方法通过改变广义瞬时无功功率计量中p-q坐标系的旋转方向和速度,得到三相三线制系统中电压、电流的任一谐波的正负序分量,进而求得正负序功率。最后将正负序功率转换成相功率,从而得到非正弦不平衡条件下的系统功率。文中方法不仅可以获得不同次谐波的功率,实现功率的正反向计量,避免不同次谐波功率抵消的现象,而且计算量小,计算精度高。最后通过Matlab仿真验证了文中方法的准确性。

Electric energy measurement based on the improved instantaneous reactive power theory

In this paper, a method of electric energy measurement based on instantaneous reactive power theory is put forward according to the deficiency that power under different frequency will be offset at the same time under the non sinusoidal and unbalanced condition. By changing the rotation direction and velocity of the coordinate system in the generalized three-phase instantaneous reactive power theory, we can obtain the positive and negative sequence voltage and current of any harmonic in the three-phase three-line system. Then the positive and negative sequence power can be converted to phase power, thus the system power under nonsinusoidal and unbalanced condition is obtained. This method can calculate the power of different harmonics, avoiding the unreasonable phenomena of power under different frequency be offset, and the calculation of this method is small and the calculation accuracy is high. Finally, the method is validated by Matlab simulation.