The Research About Reactive Power And Distortion Power Under Non-sinusoidal Condition

With the power electronics components’application in 1980s largely, many harmonics were poured into power grid. Harmonics will interfere with the measurement result of reactive power. According to the Chinese national standard, nowadays, the reactive power measured by electricity meter is the reactive power of fundamental voltage and fundamental current. But the waveforms in grid are distorted, the result computed according to national standard cannot reflect to the real reactive power when the proportion is large enough. But in this thesis, the truth has been proved that the reactive power computed according to IEEE std 1459-2010 cannot reflect the power exchange between source and load, the reasons are below:1. The reactive power computed according to IEEE std1459-2010 equals the result multiplied by the effective values of the energy storage component and total current under sinusoidal condition. But the value cannot reflect the power exchange between source and load.2. The harmonics of voltage and current will interfere with the power exchange. But the formula of reactive power in IEEE std1459-2010 does not contain the variable related to harmonics under non-sinusoidal condition.Meanwhile, the voltage distortion power, current distortion power and harmonics total distortion power in IEEE std1459-2010 also lack clear physical meaning and cannot be distinguished from reactive power.So, aiming to the two faults above, two innovation points had been raised in this thesis below:1. A simple and feasible definition with clear physical meaning of reactive power had been raised. The result computed according to the definition can reflect the velocity of the power exchange between source and load accurately.2. A new definition of distortion power had been raised. The distortion power can reflect the fluctuation of the instantaneous power relative to the only ideal instantaneous power waveform that produces same active and reactive power.At last, the author programmed according to the new definitions. Some models had been Built by Simulink of MATLAB to generate the data of voltage and current and compute the reactive and distortion power. The reactive and distortion power would be compared with the results computed according to IEEE std 1459-2010.