Operation control method and system for wind-driven generator unit in grid voltage out-of-limit range

Abstract

The invention discloses an operation control method for a wind-driven generator unit in a grid voltage out-of-limit range. The method includes the following steps: S01, during the operation of the wind-driven generator unit, detecting the grid-connected voltage of the wind-driven generator unit in real time; and S02, when the grid-connected voltage of the wind-driven generator unit is not within apreset threshold, instructing the wind-driven generator unit to output reactive power to a grid-connected point in order to ensure that the terminal voltage of the wind-driven generator unit is within a normal range and the wind-driven generator unit is not in an off-grid state. The invention also discloses a corresponding operation control system for the wind-driven generator unit in a grid voltage out-of-limit range. The system includes a first module for detecting the grid-connected voltage of the wind-driven generator unit in real-time during the operation of the wind-driven generator unit; a second module for instructing, when the grid-connected voltage of the wind-driven generator unit is not within the preset threshold, the wind-driven generator unit to output reactive power to a grid-connected point in order to ensure that the terminal voltage of the wind-driven generator unit is within a normal range and the wind-driven generator unit is not in an off-grid state. The method and system of the invention have the advantages of improving the ability of the wind-driven generator unit to be continuously connected to the grid, and increasing the utilization rate and the power generating efficiency of the wind-driven generator unit.

Description

Technical field [0001] The present invention mainly relates to the technical field of wind power generation, and particularly refers to a method and system for controlling the operation of a wind turbine in a grid voltage over-limit interval. Background technique [0002] In recent years, with the rapid growth of installed capacity of wind power, restricted by local loads and power transmission channels, the phenomenon of wind curtailment and power rationing in the Three Norths region is still serious. The development of large-scale centralized wind farms in this region has faced bottlenecks. Units have gradually changed from a large-scale wind power base development model to a small-scale, distributed wind farm development model based on load capacity planning. Since the utilization rate of distributed wind farms is relatively high and close to the load, the construction cost of power transmission channels is reduced, and the electrical transmission loss is also reduced. With t...

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Problems solved by technology

However, distributed wind farms are mainly connected to the distribution network of 35kV and below, and the poor power quality of the power grid may have a certain impact on the grid-connected operation of distributed wind turbines.

According to the distributed power grid-connected standard, the normal operating voltage range of distributed power is (85% ~ 110%) Un, where Un is the rated voltage (beyond this range is the over-limit range), when it is lower than 85% Un, the traditional wind turbine control strategy only ensures that the wind turbine will not run off-grid for a short time according to the low wear curve, if the grid voltage is lower than 85% Un for a long time, the distributed Wind turbines need to be shut down off-grid. Since distributed wind turbines are usually connected to a distribution network of 35kV and below, the distribution network is basically at the end of the grid, especially in remote areas. The distance between the distribution network is long and the impedance of the transmission line is large. Once the distribution network is connected to nonlinear loads or frequent switching of high-power motor loads, it may cause large fluctuations in the voltage of the distribution network to exceed the limit, resulting in distributed wind turbines. Reduced availability

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