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Method for measuring signal phase angle during frequency deviation of electrical power system

A power system, frequency offset technology, applied in the direction of frequency measurement device, frequency to phase shift conversion, phase angle between voltage and current, etc., can solve the problems that the accuracy is difficult to guarantee, unfavorable for online applications, etc.

Active Publication Date: 2015-02-18
STATE GRID CORP OF CHINA +1
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Problems solved by technology

This algorithm has obvious advantages in anti-harmonic interference, but it can only guarantee the measurement accuracy when the frequency deviation is small, and once the signal frequency fluctuates greatly, its accuracy is difficult to guarantee, which is not conducive to online applications.

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  • Method for measuring signal phase angle during frequency deviation of electrical power system
  • Method for measuring signal phase angle during frequency deviation of electrical power system
  • Method for measuring signal phase angle during frequency deviation of electrical power system

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Embodiment Construction

[0139] The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

[0140] Such as Figure 4 As shown, a method for measuring the signal phase angle when the power system frequency shifts, the technical solution adopted is:

[0141] 1. Sampling of power system signals;

[0142] Let the continuous signal of the power system be where ω 0 =2πf 0 is the angular frequency of the signal, f 0 Is the rated frequency of the fundamental wave, equal to 50Hz, X is the signal amplitude, φ is the initial phase angle of the signal. According to Euler's formula cosφ=(e jφ +e -jφ ) / 2 can express x(t) as

[0143] ( t ) = 2 2 X ( ...

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Abstract

The invention discloses a method for measuring a signal phase angle during frequency deviation of an electrical power system. The method is characterized by comprising the following steps of (1) sampling signals of the electrical power system; (2) mapping deviated pionic / 4 of signals; (3) calculating percentage of the frequency deviation; (4) correcting the frequency deviation; and (5) calculating phasor quantity of signals of the electrical power system. The traditional discrete Fourier transform (DFT) phase angle measuring method is low in precision; and particularly, the phase angle errors of the discrete Fourier transform method are high under the condition of frequency disturbance. Dynamic phase angle errors in phase angle errors can be reduced as far as possible by using orthogonal properties of a coordinate axis in a coordinate system and a four-phase equilibrium relation; the dynamic phase angle errors are well corrected by the method; and the phase angle measurement accuracy is improved. By an algorithm, measurement capacity on electrical power signals with various interferences is high on the premise that the frequency tracking measurement precision is guaranteed.

Description

technical field [0001] The invention relates to the technical field of auxiliary equipment related to a power system, in particular to a method for measuring the phase angle of a signal when the frequency of the power system is shifted. Background technique [0002] The concept of synchronized phasor measurement originated from the research of American scholar A.G.Phadke et al. on the "symmetrical component method distance protection" in the 1970s. Due to the need for simultaneous measurement at both ends of the fault line, it has led to the simultaneous measurement of remote locations under a unified time reference. Realization, and gradually developed into a synchrophasor measurement technology has been popularized and applied in the power system. In order to strengthen the monitoring and control of the safety and stability of the system, the National Electric Power Dispatching and Communication Center promulgated the "Technical Specifications for Real-time Dynamic Monitor...

Claims

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Application Information

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IPC IPC(8): G01R25/00G01R23/12
Inventor 朱超陈昊施涛刘永
Owner STATE GRID CORP OF CHINA
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