scholarly journals Stator Flux-Regulatory Excitation Control in Converter-Fed Synchronous Machines for Pumped-Storage Variable-Speed Hydropower

2021 ◽  
Author(s):  
Jørgen Hagset Stavnesli ◽  
Jonas Kristiansen Nøland
Keyword(s):  
Large Scale ◽  
Optimal Operation ◽  
Hydropower Plant ◽  
Technical Solution ◽  
Saturation Curve ◽  
Variable Speed ◽  
Original Design ◽  
Machine Loading ◽  
Stator Flux ◽  
Pumped Storage

Pumped-storage hydropower is seen as a promising solution for efficient, large-scale energy storage. One competitive technical solution is the variable-speed hydropower plant (VSHP) configured with a converter-fed synchronous machine (CFSM). These machines are operated with one extra degree of freedom that is not usually optimized, where the CFSM's rotor-side DC excitation interacts with the stator-side AC excitation. Depending on machine loading, the CFSM will be utilized in conditions far from its original design. In order to deal with this issue, this paper presents a stator flux control (SFC) method for regulating VSHPs in a more efficient way by adjusting the field current to prevent the machine from operating with over-magnetization independent of loading condition, as well as better utilizing the stator-fed converter current, maximizing the utilization of the CFSM. The derived first-principle analytical equations for the proposed SFC have been validated and analyzed in the Matlab/Simulink environment for a large 45 MVA, 375 rpm CFSM, with the measured saturation curve as input. Finally, dynamic transitions between different levels of pumping power reveal the SFC's ability to help to maintain a unity stator flux in the machine, enabling optimal operation independent of loading level.

scholarly journals Stator Flux-Regulatory Excitation Control in Converter-Fed Synchronous Machines for Pumped-Storage Variable-Speed Hydropower

2021 ◽  
Author(s):  
Jørgen Hagset Stavnesli ◽  
Jonas Kristiansen Nøland
Keyword(s):  
Large Scale ◽  
Optimal Operation ◽  
Hydropower Plant ◽  
Technical Solution ◽  
Saturation Curve ◽  
Variable Speed ◽  
Original Design ◽  
Machine Loading ◽  
Stator Flux ◽  
Pumped Storage

Pumped-storage hydropower is seen as a promising solution for efficient, large-scale energy storage. One competitive technical solution is the variable-speed hydropower plant (VSHP) configured with a converter-fed synchronous machine (CFSM). These machines are operated with one extra degree of freedom that is not usually optimized, where the CFSM's rotor-side DC excitation interacts with the stator-side AC excitation. Depending on machine loading, the CFSM will be utilized in conditions far from its original design. In order to deal with this issue, this paper presents a stator flux control (SFC) method for regulating VSHPs in a more efficient way by adjusting the field current to prevent the machine from operating with over-magnetization independent of loading condition, as well as better utilizing the stator-fed converter current, maximizing the utilization of the CFSM. The derived first-principle analytical equations for the proposed SFC have been validated and analyzed in the Matlab/Simulink environment for a large 45 MVA, 375 rpm CFSM, with the measured saturation curve as input. Finally, dynamic transitions between different levels of pumping power reveal the SFC's ability to help to maintain a unity stator flux in the machine, enabling optimal operation independent of loading level.

scholarly journals Analysis of Electromagnetic Force on Rotor End Windings of a 300 MW Variable-Speed Generator Motor for Pumped Storage

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Zhaowei Qiao ◽  
Yutian Sun
Keyword(s):  
Electromagnetic Force ◽  
Large Scale ◽  
Short Circuit ◽  
Element Model ◽  
Variable Speed ◽  
Distribution Map ◽  
3D Finite Element ◽  
Three Phase ◽  
Set Up ◽  
Pumped Storage

The variable-speed generator motor (VSGM) for pumped storage has a cylindrical rotor with three-phase lap or wave windings distributed in slots evenly and fed by a converter. For a large-scale VSGM, the electromagnetic force (EMF) on rotor end windings is an important contributor to distortion, vibration, and even damage of rotor end windings. A 3D finite element model of rotor end region of a 300 MW VSGM is set up. The distribution map of EMF density on involute and nose parts of rotor end windings, under rated load and three-phase short circuit at supersynchronous and subsynchronous speed, is drawn. Furthermore, the amplitude of EMF is calculated, and the radial, tangential, and axial components of EMF are analyzed. The results in this paper will lay a foundation for design of rotor end windings and their support structure.

Optimal Operation Model for Virtual Power Plant in Datong Area

2015 ◽  
Vol 785 ◽  
pp. 627-631 ◽  
Author(s):  
Hei Wei ◽  
Rasyidah Mohamed Idris
Keyword(s):  
Power Plant ◽  
Wind Power ◽  
Power Plants ◽  
Large Scale ◽  
Wind Farm ◽  
Thermal Power ◽  
Optimal Operation ◽  
Virtual Power ◽  
Virtual Power Plant ◽  
Pumped Storage

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.

scholarly journals Dual Frequency Regulation in Pumping Mode in a Wind–Hydro Isolated System

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2865 ◽  
Author(s):  
José Sarasúa ◽  
Guillermo Martínez-Lucas ◽  
Carlos Platero ◽  
José Sánchez-Fernández
Keyword(s):  
Power Systems ◽  
Power System ◽  
Frequency Control ◽  
Hydropower Plant ◽  
Frequency Regulation ◽  
Variable Speed ◽  
Dual Frequency ◽  
Pump Station ◽  
Control Scheme ◽  
Pumped Storage

Frequency control is one of the most critical tasks in isolated power systems, especially in high renewable penetration scenarios. This paper presents a new hydropower pumped-storage dual control strategy that combines variable-speed-driven pumps and fixed-speed-driven pumps. A possible case for implementation of such a control scheme is described based on El Hierro Island’s power system. This isolated power system consists of a hybrid wind pumped-storage hydropower plant and diesel generators. The pumped-storage power plant is divided into a hydropower plant equipped with four Pelton turbines and a pump station equipped with both fixed- and variable-speed pumps. According to the proposed control scheme, frequency regulation will be provided by a dual controller: a continuous controller for the variable-speed pumps and a discrete controller for the fixed-speed pumps. The Pelton units, which operate as synchronous condensers, also supply the power system inertia. Therefore, diesel units may be disconnected, decreasing generation costs and greenhouse gas emissions. Owing to the combination of both controllers and the inertia of the Pelton units, an acceptable frequency regulation can be achieved. This technique has been validated through computer simulations.

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
Keyword(s):  
Power Plant ◽  
Control Strategy ◽  
Large Scale ◽  
Frequency Converter ◽  
Position Estimation ◽  
Position Sensor ◽  
Storage Unit ◽  
Rotor Position ◽  
Start Up ◽  
Pumped Storage

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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