A fault crossing control method for wind farm based on synchronous camera

Abstract

The invention discloses a fault crossing control method of a wind farm based on a synchronous camera adjuster, which detects alternating voltage value of a grid-connected point of the wind farm in real time, and starts the synchronous camera when judging the voltage sag fault; The difference between the AC voltage standard per-unit value and the rated voltage standard per-unit value of the grid-connected point is made, and after the difference value is limited, the PI control is carried out to obtain the processed difference value; The processed difference value is added with the voltage rating per-unit value to obtain the input value of the exciter in the synchronous adjuster. The exciter changes the output reactive power of the synchronous adjuster according to the change of the input value, pulls up the voltage at the grid point until the voltage sag fault is eliminated, turns off the synchronous adjuster, and completes the fault crossing. The invention realizes the fault crossing of a wind farm in practice, solves the problem of voltage overshoot after the fault ends, and is suitable for wind farms made of different types of wind turbines.

Description

technical field [0001] The invention belongs to the field of electric power system and automation thereof, and in particular relates to a wind farm fault ride-through control method based on a synchronous condenser. Background technique [0002] Since the 21st century, due to the advantages of wide distribution of wind energy, mature wind power generation technology and low cost, the installed capacity of wind power has developed rapidly, and wind power has become the third largest power generation method in my country except thermal power and hydropower. Representative energy in new energy power generation. [0003] As the proportion of wind power generation in the power grid is increasing, the State Grid stipulates that wind farms must have a certain fault ride-through capability during faults. After the grid-connected point of the wind farm fails, the AC voltage at the grid-connected point drops. At present, both the doubly-fed asynchronous wind turbine and the permanent...

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Problems solved by technology

This method is only applicable to constant-speed and constant-frequency units, not to current mainstream variable-speed and constant-frequency units such as double-fed asynchronous wind turbines and permanent magnet synchronous wind turbines; Application of "(Ma Wenlong. Electric Power Automation Equipment, 2011,31(07):127-130.) proposed to add a crowbar circuit on the rotor side of the doubly-fed asynchronous wind turbine, which can realize the requirement of non-off-grid operation, but the crowbar circuit It will cause the doubly-fed unit to run in the state of the squirrel-cage asynchronous generator, thereby absorbing a large amount of reactive power, thereby deteriorating the grid-connected point voltage, and not suitable for other wind turbines; Research" (Zhang Xianping. High Power Converter Technology, 2010(04): 28-31.) It is proposed to add energy-consuming crowbar circuit to the DC line of the permanent magnet synchronous wind turbine to absorb the active power that cannot be transmitted, so as to realize the failure crossing, this method is also not applicable to other wind turbines

Moreover, the above two methods all need to install auxiliary devices on each wind turbine in the wind farm, which is costly and difficult to implement

"Application Analysis of Static Synchronous Compensator Enhancing Low Voltage Ride-through Capability of Wind Farm" (Qian Yeniu, Qiang Sheng, Hu Xing, et al. Guangdong Electric Power, 2012, 25(08):73-79+112) proposes the use of static synchronous The compensator performs reactive power compensation on the line to increase the fault voltage, but the design and manufacture of the static synchronous reactive power compensator is complicated and the cost is high

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