High-accuracy and anti-noise interference power grid frequency quick detection method

Abstract

The invention discloses a high-precision and anti-noise interference power grid frequency quick detection method, which comprises a power grid synchronous phase quick open loop detection link, a difference frequency phase calculation link and a frequency closed loop detection link. According to detected power grid voltage signals, through the power grid synchronous phase quick open loop detection link, the synchronous phase of the power grid can be acquired in real time, the difference frequency phase in the power grid synchronous phase is extracted through the difference frequency phase calculation link, the difference frequency phase information is inputted to the frequency closed loop detection link, and the real-time frequency of the power grid can be acquired. The power grid real-time frequency detection ability can be effectively improved, the measurement precision is high, the response speed is quick, the anti-interference performance is good, the stability problem of closed loop phase measuring and frequency measuring method in a weak power grid environment can be solved, and the application value is good.

Description

Technical field: [0001] The invention belongs to the technical field of grid frequency detection, in particular to a high-precision and noise-resistant grid frequency rapid detection method. Background technique: [0002] Frequency is a necessary quality inspection index for electric energy production and consumption, and is also an important parameter to measure the operation status of the power system. The large-scale access of renewable energy to the power grid puts forward higher requirements for the accuracy and real-time performance of power grid frequency detection. Existing frequency detection methods must rely on a phase-locked loop, also known as a software phase-locked loop (SPLL). There are three typical SPLLs: single synchronous reference frame SPLL (single synchronous reference frame SPLL, SSRF-SPLL), SSRF-SPLL based on symmetric component method, decoupled SPLL based on double synchronous coordinate system (decoupled double SRF-SPLL, DDSRF - SPLL). Among the...

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Problems solved by technology

[0004] In view of the fact that the existing power grid frequency detection must rely on the phase-locked loop, the inherent negative damping characteristics of the phase-locked loop in the weak grid environment will cause low-frequency oscillations in the local power system, and the grid frequency information cannot be accurately obtained. The invention discloses A fast grid frequency detection method with high precision and anti-noise interference. This method is based on the accurate real-time phase information detected by the open loop. By extracting the difference frequency phase, and through the difference frequency closed-loop detection link, the accurate grid frequency can be obtained. information

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