CROSS-REFERENCE TO RELATED APPLICATION

The present application is based upon and claims priority to Chinese Patent Application No. 201910987071.8, filed Oct. 17, 2019, the entire disclosure of which is incorporated herein by reference.

FIELD

The present disclosure relates to a decomposition-coordination voltage control method for wind power to be transmitted to a nearby area via flexible DC, which belongs to a technical field of voltage control for a power system.

BACKGROUND

Due to the geographical distribution of wind power resources in China, large-scale cluster wind power often needs to be delivered to the load area over a long distance. Flexible direct current (DC) has become a new choice of power transmission methods with its technical advantages, providing flexible voltage support for transmitting wind power to a nearby area (via a large-scale flexible DC grid-connected wind power collection area). However, there are dozens of wind power farms for transmitting wind power to the nearby area via flexible DC, and there are dozens or hundreds of wind turbines in each wind power farm. In order to achieve coordinated voltage control, it is necessary to sense state parameters of each wind turbine and send it to the control center, which causes a large scale of the control problem and heavy communication burden. Therefore, the traditional centralized voltage control method is difficult to achieve real-time coordinated voltage control.

SUMMARY

The present disclosure aims at overcoming shortcomings of the prior art, and proposes a decomposition-coordination voltage control method for wind power to be transmitted to a nearby area via flexible DC.

The decomposition-coordination voltage control method for wind power to be transmitted to a nearby area via flexible DC proposed by the present disclosure includes: initializing parameters comprising the number of iterations, a set value of a flexible direct voltage issued by a control center, a primary penalty coefficient and a secondary penalty coefficient; sending the parameters to wind power farms, wherein the wind power farms comprises equivalent wind power farms and wind power farms directly connected to the flexible DC, and the equivalent wind power farms are equivalent to wind power farms connected to the flexible DC via a collection station; for each of the wind power farms, establishing a voltage control optimization sub-model based on a value of voltage at each node in the wind power farm, a set value of the voltage at each node in the wind power farm, a set value of a flexible direct voltage required in the wind power farm; solving the voltage control optimization sub-model to obtain a first optimal result; for the control center, establishing a voltage control optimization main model based on the first optimal result, the primary penalty coefficient and the secondary penalty coefficient; solving the voltage control optimization main model to obtain a second optimal result; calculating a determination index based on the first optimal result and the second optimal result; and determining whether the determination index is convergent to an admissible value, if no, updating the parameters and returning to establishing the voltage control optimization sub-model.

