PMSG self-adaptation low-voltage ride-through realization method based on VRDC and DRCC

Abstract

The invention discloses a PMSG self-adaptation low-voltage ride-through realization method based on a VRDC and DRCC. In consideration of structural characteristics of a direct drive unit, on the premise that no hardware circuits are additionally arranged, unit low-voltage rid through is achieved based on the variable resistance value direct current unloading circuit (VRDC) and network side dynamic reactive coordination control (DRCC) in combination with a static var generator (SVG), wherein the VRDC and DRCC both change according to the dropping degree of voltage of a power grid so that self-adaptation of the unit to the dropping level of voltage can be achieved. During low-voltage ride-through, with unit reactive current being a reference value, the active current reference value of the unit is controlled in a coordinated mode, and therefore safe and reliable operation of the unit and a current transformer is better protected. By the utilization of the method, the supporting capacity of the unit for the power grid with reactive power and the low-voltage rid through capacity of the unit can be substantially promoted, and the stability of unit operation after fault ride-through can be improved.

Description

technical field [0001] The invention relates to the field of wind power generation, in particular to a PMSG low-voltage ride-through implementation method based on VRDC and DRCC adaptive voltage drop level. Background technique [0002] As the proportion of wind power grid-connected capacity in the power system continues to increase, the impact of wind power off-grid on the safe operation of the grid is becoming more and more serious. In recent years, wind power bases in Jiuquan, Gansu, Xinjiang and other wind power bases in our country have experienced many accidents that caused large-scale wind turbines to be disconnected from the grid due to small faults in the power grid, which has seriously affected the overall security and stable operation of the power grid system, which strongly illustrates the impact of wind power on the power system. Negative Effects. For this reason, the "Wind Power Grid-connected Technical Regulations" requires grid-connected wind farms to have l...

AI Technical Summary

Problems solved by technology

Through comparison, it is found that the current low-voltage ride-through technology for direct-drive wind turbines has more or less obvious disadvantages in terms of dynamic response speed, heat dissipation problems, control complexity, economy, fault recovery time, and regulation capabilities.

In a word, the biggest problem with the low-voltage ride-through technology of direct-drive wind turbines is that it cannot adapt well to changes in the voltage drop of the power grid to varying degrees, so that it cannot take into account the low-voltage ride-through capability of the unit during the ride-through period and the stable operation of the unit after the ride-through. ability

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