A method, device and system for improving the stability of grid-connected operation of wind turbines

Abstract

The invention discloses a wind generation set grid-connected operation stability improving method, device and system. According to the method, a magnetically controlled reactor is matched with a fixed capacitor to form a reactive power regulation device, and capacity of the reactive power regulation device can be changed through regulation of reactance values of the magnetically controlled reactor. Due to the fact that the magnetically controlled reactor is matched with the fixed capacitor, reactive compensation on inductance or capacitance is achieved, and meanwhile plenty of inductive reactive power is sent out to enhance through capacity of a wind generation set during low-voltage ride through. In addition, when failures occur, voltage at a grid-connected point falls. When a voltage transformer at the grid-connected point detects that the voltage falls to a certain degree, the magnetically controlled reactor can be removed, and only the fixed capacitor is used for supplying reactive power to a system at the maximum capacity so as to maintain grid connection of a fan and support recovery of power grid voltage to the greatest extent. When the power grid voltage recovers within a permissible range, the magnetically controlled reactor is put into operation again to be matched with the fixed capacitor to compensate the reactive power required by the system.

Description

technical field [0001] The invention relates to the technical field of electric power systems, and more specifically, relates to a method, device and system for improving the stability of wind turbine grid-connected operation. Background technique [0002] In recent years, wind power in emerging markets has developed rapidly. Under the background of national policy support and tight energy supply, wind power, especially wind power equipment manufacturing, has also risen rapidly in various countries, and has become the most active place for wind power in the world. As a clean and renewable energy, wind energy has been paid more and more attention by countries all over the world. However, wind power has the characteristics of volatility and uncertainty, which will have adverse effects on the operation of wind power generators, for example: affecting the active power output by wind power generators, and the fluctuations in reactive power caused by wind power fluctuations will c...

AI Technical Summary

Problems solved by technology

However, wind power has the characteristics of volatility and uncertainty, which will have adverse effects on the operation of wind power generators, for example: affecting the active power output by wind power generators, and the fluctuations in reactive power caused by wind power fluctuations will change wind power generation. The reactive power fluctuation of the machine and the terminal voltage fluctuation. In addition, when the wind turbine is running in grid connection, the reactive power demand of the wind turbine will have an adverse impact on the voltage of the grid connection point.

[0003] In order to eliminate the above-mentioned adverse effects, the dynamic compensation of reactive capacity in the prior art is realized by a static var compensator, that is, by a varactor. Please refer to the attached figure 1 , is the structure diagram of the traditional static var compensator, which relies on the thyristor to control the switching reactor to realize the continuous variable adjustment of reactive capacity, but because the switching element in the varactor and the reactor are connected in series Into the circuit, the current value is large, so the requirements for the flow capacity of the power electronic components are high, the manufacturing cost is increased, and the active power loss is large; in addition, for the thyristor, it is extremely easy to damage and the maintenance pressure is high. At the same time, Since the switching element changes the magnitude of the effective current flowing through the reactor by delaying the firing angle, the current waveform has higher harmonic content and slower response speed

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