Method for regulating terminal voltage by reactive power support of double-fed wind generator unit and system thereof

Abstract

The invention relates to a method for regulating terminal voltage by reactive power support of a double-fed wind generator unit and a system thereof. The method includes steps of initializing the system, measuring terminal voltage and calculating errors e, judging whether the errors e is in a dead zone or not and calculating reactive power reference QPI, calculating the maximum reactive power capacity Qmax, defining reactive power control commands Qout according to the QPI and Qmax, and driving the double-fed wind generator unit to send out corresponding reactive power according to the reactive power control commands Qout. The system comprises an electric energy mass module, a dead zone hysteresis comparator, a PI (proportional plus integral) controller, a reactive power capacitor calculation module, a current converter and the double-fed wind generator unit. The decoupling control characteristics of active power and reactive power of the double-fed wind generator unit are given full play, dynamic regulation of voltage of the double-fed wind generator unit is realized, and the quality of the power grid is improved. Meanwhile, capacity of an SVC (static var compensator) and an SVG (static var generator) of existing reactive regulating equipment are decreased and cost is reduced.

Description

technical field [0001] The invention relates to the field of wind power generation, in particular to a machine terminal voltage regulation method and system for reactive power support of a doubly-fed wind turbine. Background technique [0002] In recent years, with the continuous development of wind power generation, the installed capacity of wind farms has increased year by year, and the proportion of wind power generation has become larger and larger, and it has gradually become a conventional energy source. However, the randomness of wind energy makes the output power and voltage of wind turbines have certain random fluctuations, which will have a certain impact on the quality of the power grid. With the expansion of the capacity of a single wind turbine in my country and the increase in the proportion of the total installed capacity in the national grid, the scope of influence of wind turbines on the grid is gradually expanding and the degree of influence is also deepeni...

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Problems solved by technology

[0003] For this problem, there are currently two solutions: one is to increase the working voltage level of all electrical components inside the wind turbine and replace them with electrical equipment that can withstand 1.3 times the rated voltage, which will consume a lot of manpower and material resources. And it is a passive method to meet the requirements, unable to adapt to possible new changes in the future; the second is to put in more reactive power compensation equipment such as SVC and SVG to realize the voltage adjustment function, and adjust the machine terminal voltage to 0.9 through reactive power support. -1.1 times the rated voltage range, but this will increase the input cost, and it is difficult to realize the dynamic adjustment of the machine terminal voltage

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