Method and system for detecting electric power signal frequency based on phase modulation

A phase modulation and power signal technology, which is applied in the power field, can solve the problems of low frequency measurement accuracy, achieve high frequency measurement results, high precision, suppress noise or attenuate sub-harmonic and sub-harmonic interference effects
CN104502701AActive Publication Date: 2015-04-08ELECTRIC POWER RES INST OF GUANGDONG POWER GRID
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
ELECTRIC POWER RES INST OF GUANGDONG POWER GRID
Publication Date
2015-04-08

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Abstract

The invention discloses a method and a system for detecting electric power signal frequency based on phase modulation. The method comprises the following steps of sampling electric power signals according to preset signal time duration and preset sampling frequency to obtain an input signal sequence; measuring the frequency of the input signal sequence to obtain the initial frequency of the electric power signals, and subtracting the input signal sequence from the + / - 1 phi phase-shift sequence of the input signal sequence by taking the initial frequency as a reference frequency to obtain two phase modulation sequences of which the phase positions vary along with the input signal frequency, wherein the two phase modulation sequences are used for frequency measurement. Through the implementation of the method and the system, the frequency measurement result with higher precision can be obtained.
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Description

【Technical field】

[0001] The invention relates to the field of electric power technology, in particular to a method and system for detecting the frequency of electric power signals based on phase modulation. 【Background technique】

[0002] Power frequency measurement is of great significance to the power system. The rated power frequency of power grid operation is 50Hz, which is a relatively low frequency. The frequency of low-frequency signals can be measured according to the phase difference. The basic principle is to take two data sequences separated by intervals and measure the frequency according to the phase difference of the two data sequences.

[0003] However, there are sub-harmonic and sub-harmonic interferences in the actual power signal. The two-segment data sequence does not have frequency-domain filtering characteristics, and cannot suppress or attenuate sub-harmonic and sub-harmonic interference, which will reduce the frequency measurement precision. 【Conte...

Claims

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