Method for improving grid-connected transient stability in wind farm voltage automatic control system

Abstract

The invention provides a method for improving grid-connected transient stability in an automatic voltage control system of a wind power plant. A wind power plant AVC (Asia vital component) system comprises an AVC controller, a plurality of fan master control systems, an SVC (static var compensator), and a plurality of voltage transformers and current transformers, wherein each wind power collection circuit is connected with a plurality of fans; and the AVC controller communicates with each fan master control system, and is electrically connected to the plurality of voltage transformers and current transformers. The method comprises the steps that the AVC controller determines whether the voltage of a PCC (programmable computer controller) point of a wind power grid is suddenly reduced; when the voltage of the PCC point is suddenly reduced, the AVC controller locks the control of the wind farm AVC system after waiting for a first preset time; when the SVC is absorbing reactive power, the AVC controller emits a control command, so that the SVC stops absorbing the reactive power; the AVC controller determines whether the voltage of the PCC point ascends over a specific threshold within a second preset time after the sudden reduction, and when the voltage of the PCC point ascends over the specific threshold within the second preset time, the AVC controller restores the control of the wind farm AVC system.

Description

technical field [0001] The invention relates to a dynamic automatic voltage control (AVC) of a wind farm, and more specifically, relates to a method for improving the transient stability of a wind farm connected to a grid in the AVC system of a wind farm. Background technique [0002] With the development of technology, the attention and utilization of renewable energy are increasing day by day. Among them, wind power generation is a relatively mature energy technology. However, my country's wind power industry's development plan of "building large bases and integrating into large power grids" is different from Europe's "distributed grid connection and local consumption", and has the characteristics of "large-scale" and "high concentration". Intermittent wind power causes grid voltage fluctuations, increases in system short-circuit capacity, and changes in transient stability, especially when large-scale wind power is connected to the grid. At the same time, the power quali...

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Problems solved by technology

[0009] Although SVC has the ability to improve the transient stability of wind farms connected to the grid, SVC still has many disadvantages: (1) SVC is expensive, so the design capacity is limited and the adjustment ability is limited; (2) as the voltage decreases, SVC generates reactive power The power capability decreases, so it is difficult to guarantee the adjustment effect when the voltage suddenly drops; (3) The combined SVC has a large impact current during adjustment, especially when switching capacitors and reactors, the impact current is more than twice the rated value; (4) )SVC does not cooperate with the low-voltage ride-through function of the fan, which will cause voltage over-regulation or under-regulation

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