Research and Develop on Static Frequency Converter of Pumped Storage Power Plant

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.

2012 ◽  
Vol 24 ◽  
pp. 155-162 ◽  
Author(s):  
Deshun Wang ◽  
Bo Yang ◽  
Guanjun Li ◽  
Yibin Tao ◽  
Bingyu Sang

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2423 ◽  
Author(s):  
Yuanlin Wang ◽  
Xiaocan Wang ◽  
Wei Xie ◽  
Manfeng Dou

For salient-pole permanent magnet synchronous motor (PMSM), the amplitude of extended back electromotive force (EEMF) is determined by rotor speed, stator current and its derivative value. Theoretically, even at extremely low speed, the back EEMF can be detected if the current in q-axis is changing. However, it is difficult to detect the EEMF precisely due to the current at low speed. In this paper, novel full-order multi-input and multi-output discrete-time sliding mode observer (SMO) is built to detect the rotor position. With the proposed rotor position estimation technique, the motor can start up from standstill and reverse between positive and negative directions without a position sensor. The proposed method was evaluated by experiment.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261093
Author(s):  
Wentao Huang ◽  
Jinman Yu ◽  
Zhijun Yuan ◽  
Zhongwei He ◽  
Jun He ◽  
...  

With the construction and development of ultra-high voltage (UHV) power grids, large-scale, long-distance power transmission has become common. A failure of the connecting line between the sending-end power grid and the receiving-end power grid will cause a large-scale power shortage and a frequency drop in the receiving-end power grid, which can result in the frequency collapse. Presently, under-frequency load shedding (UFLS) is adopted for solving the frequency control problem in emergency under-frequency conditions, which can easily cause large load losses. In this context, a frequency coordination optimal control strategy is proposed, which combines the mode transition of pumped storage units with UFLS to deal with emergency under-frequency problems. First, a mathematical model of the frequency dynamic response is established, which combines the mode transition of pumped storage units with UFLS based on a single-machine equivalent model. Then, an optimal model of the minimal area of the power system’s operation frequency trajectory is introduced, yielding the optimal frequency trajectory, and is used for obtaining the action frequency of the joint control strategy. A simulated annealing algorithm based on the perturbation analysis is proposed for solving the optimal model, and the optimal action frequency is obtained that satisfies the transient frequency offset safety constraint of the power system. Thus, the joint optimal control of the mode transition of the pumped storage units and UFLS is realized. Finally, the EPRI-36 bus system and China’s actual power grid are considered, for demonstrating the efficiency of the proposed strategy.


Author(s):  
Feng Dong ◽  
Hao Chen ◽  
Shuai Xu ◽  
Sihang Cui

Purpose This paper aims to present a novel position sensorless control scheme with fault-tolerance ability for switched reluctance motor at low speed. Design/methodology/approach First, the detection pulses are injected in the freewheeling and idle intervals of each phase. Second, the aligned position of each phase can be detected by comparing the consecutive rise time of detection current. Third, the whole-region rotor position and real-time rotational speed can be updated four times for the improvement of detection accuracy. Finally, the fault-tolerant control strategy is performed to enhance the robustness and reliability of proposed sensorless scheme under faulty conditions. Findings Based on proposed sensorless control strategy, the estimated rotor position is in good agreement with the actual rotor position and the maximum rotor position error is 1.5°. Meanwhile, the proposed sensorless scheme is still effective when the motor with multiphase loss and the maximum rotor position error is 1.9°. Moreover, the accuracy of the rotor position estimation can be ensured even if the motor is in an accelerated state or decelerated state. Originality/value The proposed sensorless method does not require extensive memory, complicated computation and prior knowledge of the electromagnetic properties of the motor, which is easy to implement. Furthermore, it is suitable for different control strategies at low speed without negative torque generation.


2018 ◽  
Vol 177 ◽  
pp. 592-604 ◽  
Author(s):  
Yanhe Xu ◽  
Yang Zheng ◽  
Yi Du ◽  
Wen Yang ◽  
Xuyi Peng ◽  
...  

2015 ◽  
Vol 785 ◽  
pp. 627-631 ◽  
Author(s):  
Hei Wei ◽  
Rasyidah Mohamed Idris

Datong area has abundant wind energy. Due to problem in large scale of wind power grid connection, this paper introduces virtual power plant concept. As for beginning, power source characteristics of the wind farm, pumped storage power station and the thermal power plant are taken for analysis. Three types of different power plants are chosen to represent the virtual power plant modeling as well as adopting the NSGA2 optimization. As a conclusion, this case study proved that virtual power plant can increase the benefits of each power plant and the wind power plant output power curve become smoother.


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.


2021 ◽  
Vol 1985 (1) ◽  
pp. 012051
Author(s):  
Tao Liu ◽  
Chao Wang ◽  
Zhiming Chen ◽  
Funan Chen ◽  
Huili Bi ◽  
...  

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jingwei Cao ◽  
Liming Zhai ◽  
Yongyao Luo ◽  
Soo-Hwang Ahn ◽  
Zhengwei Wang ◽  
...  

PurposeThe purpose of this paper is to reveal the transient thermo-elasto-hydrodynamic lubrication mechanism of a bidirectional thrust bearing in a pumped-storage unit, and to propose the transient simulation method of two-way fluid-solid-thermal interaction of thrust bearing.Design/methodology/approachThe transient fluid-solid-thermal interaction method is used to simulate the three-dimensional lubrication of the thrust bearing, during the start-up and shutdown process of a pumped storage unit. A pad including an oil hole is modelled to analyze the temporal variation of lubrication characteristics, such as the film pressure, thickness and temperature, during the transient operation process.FindingsThe injection of the high-pressure oil sufficiently affects the lubrication characteristics on film, in which the hysteresis phenomena were found between the start-up and shutdown possess.Originality/valueThis paper reveals the transient lubrication mechanism of tilting pad in a thrust bearing, by means of transient fluid-solid-thermal interaction method. Lubrication characteristics are simulated without assuming the temperature relationship between the oil film inlet and the outlet and the heat transfer on the pad free surface. This paper provides a theoretical basis for the safe design and stable operation of thrust bearings.


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