Real-time digital detection method for active power and reactive power of electricity grid

Abstract

The invention discloses a real-time digital detection method for active power and reactive power of an electricity grid. The method mainly comprises the following schemes of: 1, simultaneously sampling a voltage signal and a current signal by a fixed sampling frequency to obtain a voltage sampling sequence and a current sampling sequence so as to obtain instant active power; 2, calculating Hilbert transformation of the voltage signal by using windowing discrete Fourier transform (DFT) and inverse discrete Fourier transform (IDFT) to obtain instant reactive power; and 3, designing a high-performance finite impulse response (FIR) comb filter by utilizing a rectangular self-convolution window, and efficiently filtering fundamental waves and harmonic components of each time in an instant power signal to obtain the accurate active power and the accurate reactive power. In a novel high-precision algorithm for measuring electric power by a microcomputer, orders of the rectangular self-convolution window can be selected in accordance with actual demands, and high-precision estimation on the active power and the reactive power are realized under synchronous error during sampling. Moreover, the method has the advantages of small computation and high precision and particularly has practical engineering values.

Description

technical field [0001] The invention belongs to the technical field of electric engineering and relates to a digital real-time detection method for active power and reactive power of a power grid. Background technique [0002] Active power and reactive power are important parameters for power system operation, monitoring, control and measurement. Based on the Budeanu definition of electric power and the practical definition recommended by IEEE, the digital measurement algorithms of active and reactive power are mainly divided into two categories. One type is based on frequency domain analysis, which first calculates the amplitude and phase of the fundamental wave and harmonics in voltage and current, then calculates the active and reactive power of each frequency component, and finally sums to obtain the total power. Another type of algorithm is based on time-domain integration, which obtains active and reactive power by integrating the instantaneous active power (the produ...

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Problems solved by technology

[0003] When the time-domain integration method is used to measure reactive power, it is necessary to take the Hilbert transform of the voltage signal; since the ideal Hilbert transform is physically unrealizable, the actual Hilbert transform is generally approximated by an IIR or FIR digital filter, and the Hilbert transform error will lead to reactive power Measurement error

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