Multi-cycle sampling frequency compensation method

Abstract

The invention provides a multi-cycle sampling frequency compensation method which comprises the following steps: sampling two kinds of frequency aliasing signals so as to acquire discrete data of the aliasing signals, wherein the acquisition time has a special time length related to a power frequency cycle; designing a narrowband digital filter which is used for separating the discrete data of the aliasing signals; and separating the discrete data by the designed narrowband digital filter so as to acquire pilot frequency separation signals. According to the invention, the pilot frequency test can be accurately and stably carried out during separation of a signal frequency domain.

Description

technical field [0001] The invention relates to the technical field of power system power transmission and transformation equipment testing, in particular to a multi-cycle sampling frequency compensation method. Background technique [0002] The positive-sequence parameters and zero-sequence parameters of high-voltage transmission lines, as well as the mutual impedance and coupling capacitance between lines are important system parameters of the power grid, and are an important basis for power grid protection setting, reactive power compensation, and structural optimization. Operating procedures ("Code for Construction and Acceptance of Overhead Power Transmission Lines", "Regulations for Start-up and Acceptance of Power Transmission and Transformation Basic Construction Projects of 110 kV and Above", "Operation Management Regulations for Relay Protection and Safety Automatic Devices" and "DL / T559-94 ", "DL / T584-95", etc.) stipulates that after the transmission line is newly...

AI Technical Summary

Problems solved by technology

Since the frequency point of the test signal in the different frequency test is very close to the frequency point of the power frequency (50Hz), generally ±2.5Hz or ±5Hz is taken, which will inevitably cause the signal data sequence to sample the non-full cycle of the different frequency test signal, although a variety of method to make up the entire period, it will inevitably lead to spectrum leakage in the frequency domain, resulting in systematic error

Only when the signal-to-noise ratio is 2:1 can the attenuation requirement of 20db be met. Under the existing interference environment conditions, the test power supply system is huge, and the accuracy and stability of the test result data cannot meet the measurement requirements.

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