Reactive power metering system in electric energy meter

The invention provides a reactive power metering system in an electric energy meter. The reactive power metering system comprises a voltage signal input channel, a current signal input channel and a multiplying unit. The voltage signal input channel and the current signal input channel each comprise an ADC, an HPF and an ACF, wherein the ADC samples an analog voltage or current signal and converts the analog voltage or current signal into a digital voltage or current signal; the HPF is connected with the ADC and removes direct current components in the digital voltage or current signal; the ACF is connected with the HPF and performs precompensation on the amplitude of the digital voltage or current signal. The voltage signal input channel further comprises an LPF connected with the ACF of the voltage signal input channel and performs -90-degree phase shifting operation on frequency components of the digital voltage signal. The multiplying unit is connected with the LPF and the ACF of the current signal input channel and multiplies the digital voltage signal and the digital current signal to obtain real-time reactive power. The amplitude-frequency characteristics of the two ACFs are designed according to the amplitude-frequency characteristic of the LPF, and the ACFs and the LPF act jointly to counteract the attenuation effect on the digital voltage signal of the LPF in the key frequency range close to the power frequency signal frequency. The reactive power metering system can perform compensation operation in the reactive power operation and is simple in mode and high in metering accuracy.