scholarly journals Analysis of Control Characteristics and Design of Control System Based on Internal Parameters in Doubly Fed Variable-Speed Pumped Storage Unit

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Guopeng Zhao ◽  
Yongxin Zhang ◽  
Jiyun Ren

In this paper, the control strategies and their characteristics when applied to the doubly-fed variable-speed pumped storage unit in generating mode and pump mode are discussed. The composition of doubly fed variable-speed pumped storage unit is introduced, and the mathematical model of every component is proposed. Two control strategies of the unit are introduced. One is the power priority control strategy and the other is the speed priority control strategy. Then, the control block diagrams of the two control strategies in the generating mode and the pump mode are established, and the parameters of the unit in each control strategy are designed. The two control strategies are simulated in power generation and pumping conditions. Finally, the conclusion that power priority strategy has a better effect on power control is obtained.

2019 ◽  
Vol 9 (16) ◽  
pp. 3368 ◽  
Author(s):  
Guopeng Zhao ◽  
Jiyun Ren

The doubly-fed variable-speed pumped storage (DFVSPS) is an effective method to balance the fluctuation of renewable energy generation and is an important means of frequency and voltage regulation of a power grid. Firstly, this paper introduces the structure and mathematical model of the DFVSPS unit. Secondly, the control methods of each switching stage in generating mode and pump mode are proposed, and the simulation study of each stage of DFVSPS switching process is carried out by MATLAB/Simulink. Thirdly, when studying the regulating effect of DFVSPS unit in the power system, due to the high switching frequency of converter in the electromagnetic transient model, the simulation speed is very slow and the data volume is large, so the model of DFVSPS unit needs to be simplified. By analyzing the dynamic behavior of the pumped storage power station, the mathematical model of output power of the DFVSPS unit is established, which includes start-up stage, load ramping stage, stable operation stage, load rejection stage and shutdown stage of generating mode and pump mode. Finally, the simplified model of DFVSPS unit is applied to a simple power system to verify its regulating effect on grid power.


Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 204
Author(s):  
Zhiwei Zhu ◽  
Xiaoqiang Tan ◽  
Xueding Lu ◽  
Dong Liu ◽  
Chaoshun Li

The doubly-fed variable speed pumped storage unit is a storage system suitable for joint operation with renewable energy sources to smooth the imbalance between renewable energy supply and electricity demand. However, its working principle and operation control are more complex than those of constant speed pumped storage. In this study, a nonlinear model of doubly-fed variable speed pumped storage units (VSPSUs) considering nonlinear characteristics of the head loss is established. The study finds that a supercritical Hopf bifurcation occurs in the system, and the area enclosed by the lower side of the bifurcation line and the coordinate axis is the stability domain of the system. The active power step perturbation from −0.3 to 0.3 will gradually reduce the area of the stability domain and narrow the adjustable range of the control parameters. In addition, the sensitivity of the model full state variables and the primary and secondary relationships to the changes of subsystem parameters is analyzed systematically using the trajectory sensitivity. It is found that there is a large difference in the sensitivity of different state variables to the parameters. The state variables are much more sensitive to the transfer coefficient of hydraulic turbine torque to guide vane opening, the unit inertia time constant, and the controller proportional gain change than other parameters, which are defined as highly sensitive parameters. The receiver response time constant and the turbine flow-to-head transfer coefficient are the corresponding low-sensitivity parameters.


2021 ◽  
Vol 252 ◽  
pp. 02022
Author(s):  
Haoyuan Li ◽  
Guanjun Li ◽  
Bo Yang ◽  
Liantao Ji

Constant speed pumped storage unit is widely used, however it cannot adjust the input power when working in the electric mode, and cannot work in the best efficiency when the head of the reservoir changes greatly. Therefore, it is necessary to study and develop the variable speed pumped storage systems. This paper has studied on variable speed operation of static frequency converter for pumped storage units. Besides, development status of variable speed pumped storage system at home and abroad is investigated. Furthermore, classification and advantages and disadvantages of variable speed pumped storage system are also introduced, mainly including two typical variable speed pumped storage systems, i.e., doubly-fed variable speed system and full power variable speed system.


Author(s):  
Zheng Tan ◽  
Lili Hao ◽  
Tingting Liang ◽  
Tao Wu ◽  
Shanying Li ◽  
...  

2012 ◽  
Vol 608-609 ◽  
pp. 1120-1126 ◽  
Author(s):  
De Shun Wang ◽  
Bo Yang ◽  
Lian Tao Ji

A static frequency converter start-up control strategy for pumped-storage power unit is presented. And rotor position detecting without position sensor is realized according to voltage and magnetism equations of ideal synchronous motor mathematics model. The mechanism and implementation method of initial rotor position determination and rotor position estimation under low frequency without position sensor are expounded and validated by simulations. Based on the mentioned control strategy, first set of a static frequency converter start-up device in China for large-scale pumped-storage unit is developed, which is applied to start-up control test in the 90 MW generator/motor of Panjiakou Pumped-storage Power Plant. Test results show that rotor position detecting, pulse commutation, natural commutation, and unit synchronous procedure control of static start-up are all proved. The outcomes have been applied in running equipment, which proves the feasibility of mentioned method.


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