Device and method for detecting power grid

Abstract

The invention relates to a device and method for detecting a power grid. The device comprises a high-voltage large-current processing circuit, an analog-to-digital (AD) sampling circuit, a frequency detecting circuit, a digital signal processor (DSP) processing circuit, a communication circuit and a power supply circuit for supplying power to the circuits. Output signals of the high-voltage large-current processing circuit are processed through the AD sampling circuit and the frequency detecting circuit respectively and sent to the DSP processing circuit, and the DSP processing circuit is connected with the communication circuit. The method includes: processing high voltage and large current to obtain distortionless low-voltage signals in equal proportion; collecting processed low-voltage signals, and converting the low-voltage signals into digital signals and square signals in the same frequency; and calculating and processing the obtained digital signals and the square signals, and analyzing and judging fault information and communicating with the outside according to calculating results. The device and method has the advantages of being fast in processing of various parameters of voltage and current on a power grid side and capable of storing power grid fault information and alarming.

Description

technical field [0001] The invention relates to the technical field of wind power, in particular to a grid detection device and a detection method thereof. Background technique [0002] The detection of the voltage and current signals on the grid side of the wind turbine is a very important function of the main control system of the wind turbine, and it has always been realized through the electric energy meter. Commonly used watt-hour meters can be used to detect the effective value of voltage, current, frequency, power factor, active power, reactive power, apparent power, etc. of the wind turbine grid side. With the continuous improvement of wind power generators' requirements for grid-side detection, this type of energy meter will become increasingly unable to meet actual needs. [0003] see figure 1 As shown, the electric energy meter currently used in wind turbines is mainly controlled by a professional electric energy metering IC plus a single-chip processor, in whic...

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Problems solved by technology

[0005] 1. The standard frequency of the grid is 50HZ, that is, the signal period of the grid voltage is 20ms, so the energy meter often needs more than 10 cycles to calculate the grid signal, and the response speed is very slow. When the grid fails, it cannot be accurate and timely The status information of the response grid;

[0006] 2. When the power grid fails, it is often instantaneous, and the duration of the fault is often very short. The energy meter cannot record the grid fault in time, which makes it difficult to analyze the grid fault;

[0007] 3. The electric energy meter can only perform simple measurement on the power grid, but cannot give an alarm to the power grid failure, so it is not conducive to the self-protection of the wind turbine

[0008] It can be seen that there are still obvious deficiencies in the use and method of the detection method and device for the power grid in the prior art, and further improvement is urgently needed

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