Protection system and method for pitch system during wind power grid phase loss fault

Abstract

The invention discloses a system and a method for protecting a pitch system in a wind power generating set grid phase failure. The state is controlled by the auxiliary contact of the intermediate relay powered by the switching power supply; the intermediate relay is connected to the driver, and the driver can determine the input or output signal according to whether the DC bus voltage exceeds the limit. The invention can eliminate hidden dangers such as overspeed and load overrun caused by the pitch control system when the grid voltage lacks phase, and improves the safety performance and automation degree of the unit.

Description

technical field [0001] The invention relates to the field of wind power generation, in particular to a protection system and method for a pitch system during a phase loss fault of a power grid of a wind power generating set. Background technique [0002] With the rapid development of the wind power industry, the installed scale and unit capacity are increasing, and it is particularly important to simultaneously improve the safety performance and automation of the unit. As an important part of the protection function of the wind turbine, the pitch control system is a necessary condition for the long-term stable operation of the equipment to complete the pitch change action in a timely and effective manner when the unit triggers a fault. [0003] Restricted by the fact that most of the pitch system drivers are imported brands, it is difficult for customers to change the underlying program, the external power supply is uncontrollable and the internal control logic and other fac...

AI Technical Summary

Problems solved by technology

[0003] Restricted by the fact that most of the pitch system drivers are imported brands, it is difficult for customers to change the underlying program, the external power supply is uncontrollable and the internal control logic and other factors, the pitch system of the currently running unit, the grid voltage phase loss fault, the voltage short When the time rises to a high level (≥1.3pu), the bus voltage of the driver will exceed the protection limit after being rectified by the uncontrollable rectifier bridge, and the driver will protect itself and no longer perform protection actions

And when the grid voltage returns to normal and the bus voltage of the drive returns to below the threshold, the drive cannot self-reset in time, and the entire pitch system does not operate for up to 50s, making it difficult to achieve timely, fast and effective propeller retraction, which can easily cause short-term overspeeding of the unit. Problems such as load exceeding the limit, there are great potential safety hazards

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