Research on Primary Frequency Regulation Control Strategy of Wind-thermal Power Coordination

Jihong Zhang,Bin He,Xiaoling Dong,Peihong Yang,Ya Li,Yao Wang,Li Kuang

doi:10.1109/access.2019.2946192

Jihong Zhang, Bin He + Show 5 more

Open Access

https://doi.org/10.1109/access.2019.2946192

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Abstract

With the increase of wind power penetration in the electric grid, the frequency regulation method that simply reply on traditional power is gradually weakened. For this reason, the participation of wind power in system frequency regulation has become an inevitable trend in the operation of large-scale grid-connected power system. Focused on the essential difference of the frequency response speed between wind turbine and thermal power unit, a primary frequency regulation control strategy for large-scale wind power cooperative thermal power units is proposed to realize frequency regulation in the full wind speed range of doubly-fed wind turbines and improve the frequency response capability of large-scale wind power access to system. Firstly, the frequency regulation response strategy of wind turbine based on rotor kinetic energy control and power reserve control and the control strategy of rotor speed recovery are studied to improve the frequency regulation capability of wind power system. Secondly, the optimal distribution of frequency regulation power of the large-scale wind farms is realized according to the establishing of the power distribution strategy based on weight factor of each turbine in the wind farm in different operating scenarios Finally, the control framework of wind-thermal power coordination frequency regulation is constructed. The system power shortage is distributed to the wind farm and the thermal power unit in real time by the dispatch center according to the wind farms' and thermal power unit's operating states and the variation of system frequency, by which the wind-thermal power coordination frequency regulation of power system can be achieved. Simulation results of the 36-node test example demonstrate that the proposed strategy can effectively improve the frequency response capability and the frequency characteristics of the power system.

Highlights

As a kind of renewable energy generation, wind generation technology has gradually entered the stage of largescale development with the increasing penetration of the wind energy in electric system in last decades
1) SCENARIO 1 As mentioned above, when a wind turbine operates in the low wind speed segment, the rotor kinetic energy control method is applied by it to participate in the system frequency regulation which includes the virtual inertia control and the droop control, and the performance of the integrated frequency regulation control strategy proposed in this paper are compared with them
The rotor of wind turbines is complete decoupled with the grid frequency which makes it fails to respond to the change of the system frequency and participate in power system frequency regulation

Summary

INTRODUCTION

As a kind of renewable energy generation, wind generation technology has gradually entered the stage of largescale development with the increasing penetration of the wind energy in electric system in last decades. Focusing on the above problems, and considering the characteristics of fast frequency response and small inertia time constant of wind turbine and the long-lasting frequency regulation capability of thermal power unit, a control strategy for large-scale wind farm cooperated with thermal power plant participating in the primary frequency regulation of system is proposed. On the wind turbine level, the frequency strategy of kinetic energy control and pitch angle control is proposed, and the rotor protection and variable parameter speed delay recovery strategy are added to the rotor kinetic energy control to improve the frequency response capability of the wind turbine.

FREQUENCY REGULATION STRATEGY OF THE WIND TURBINE

CONCLUSION