scholarly journals Characteristic Analysis and Optimal Regulation of Primary Frequency Regulation Condition in Low Water Head Area Based on Hydraulic-Mechanical-Electrical Coupling Model of Pumped Storage Unit

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Cong Lv ◽  
Yanhe Xu ◽  
Xin Wu ◽  
Qing Zhang
Keyword(s):  
Power Grid ◽  
Electrical Coupling ◽  
Frequency Regulation ◽  
Regulation System ◽  
Optimization Strategy ◽  
Power Station ◽  
Storage Unit ◽  
Pump Turbine ◽  
Pumped Storage ◽  
Primary Frequency

Pumped storage power station is an important regulating tool for peak load regulation and frequency regulation of the power grid, especially its primary frequency regulation function, which is of profound significance for the safety and stability of the power grid. As the core equipment of the pumped storage power station, the reversible design of the pump turbine makes it easy to have hydraulic fluctuation and mechanical instability when the unit runs to the “S” characteristic area, which will cause the frequency oscillation of the generator under the condition of primary frequency regulation. Therefore, some innovative work is studied in this paper: (1) an accurate hydraulic-mechanical-electrical coupling system mathematical model of pumped storage unit regulation system (PSURS) is established based on full characteristic curve of the pump turbine and seventh-order synchronous generator and excitation system; (2) the dynamic response characteristics of primary frequency regulation of pumped storage unit (PSU) under different water heads and different frequency disturbances are analyzed by numerical simulation; (3) in view of the unstable condition of the unit under the large frequency disturbance when it operates in the low head and small load area, the objective optimization function considering the ITAE index of hydraulic, mechanical, and electrical factors is proposed; and (4) fractional-order PID controller and the bacterial-foraging chemotaxis gravitational search algorithm (BCGSA) combined optimization strategy is used for PSURS optimization regulation and parameter optimization. The results show that the joint optimization strategy proposed in this paper has smaller objective function value, and makes the PSURS pass through the unbalanced area quickly, with better primary frequency regulation speed and smaller regulation depth.

Research on the Primary Frequency Regulation of the Large Capacity Thermal Power Units

2014 ◽  
Vol 608-609 ◽  
pp. 915-919 ◽  
Author(s):  
Hong Xia Wu
Keyword(s):  
Power Plant ◽  
Control Method ◽  
Power Grid ◽  
Thermal Power ◽  
Frequency Regulation ◽  
Load Curve ◽  
Large Capacity ◽  
Continuous Increase ◽  
Important Index ◽  
Primary Frequency

Frequency is an important index of power quality, primary frequency regulation is of great significance for maintaining the grid frequency. In recent years, with the expansion of the power grid capacity and the continuous increase of the generator capacity, the large capacity units play a role is becoming more and more important in the primary frequency regulation of power grid. This paper takes ultra supercritical coal-fired units (1000MW) of a power plant of Hubei for example, primary frequency regulation control method, requency offset load curve and so on were studied through relevant test.

scholarly journals Characteristics Analysis and Fuzzy Fractional-Order PID Parameter Optimization for Primary Frequency Modulation of a Pumped Storage Unit Based on a Multi-Objective Gravitational Search Algorithm

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 137 ◽  
Author(s):  
Xin Wu ◽  
Yanhe Xu ◽  
Jie Liu ◽  
Cong Lv ◽  
Jianzhong Zhou ◽  
...  
Keyword(s):  
Fractional Order ◽  
Pid Controller ◽  
Search Algorithm ◽  
Gravitational Search Algorithm ◽  
Storage Unit ◽  
Water Head ◽  
Pumped Storage ◽  
The Stability ◽  
Primary Frequency ◽  
Fractional Order Pid

Compared with conventional hydropower units, the pumped storage unit has the characteristics of diverse working conditions and frequent switching. Therefore, the stability and regulation quality of the primary frequency modulation transition process of the regulating system is very important. Due to the “S” characteristics of the pumped storage unit (PSU), the pumped storage unit regulating system has a strong nonlinearity, and the conventional proportional-integral-derivative (PID) controller cannot provide high-quality control under low water head conditions. In this paper, the nonlinear PSU model with an elastic water hammer effect is studied, and the fuzzy fractional-order PID (FFOPID) controller is designed to improve the stability of the system. The membership function and the control parameters of the fractional-order PID are optimized based on the multi-objective gravitational search algorithm (MOGSA). The experimental results show that the optimized design of the FFOPID controller has better control quality than the traditional PID controller, the fractional-order PID (FOPID) controller, and the fuzzy PID controller (FPID) when the system is disturbed by the rotating speed under low water head.

scholarly journals A Review of Critical Stable Sectional Areas for the Surge Tanks of Hydropower Stations

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6466
Author(s):  
Wencheng Guo ◽  
Yang Liu ◽  
Fangle Qu ◽  
Xinyu Xu
Keyword(s):  
Electrical Coupling ◽  
Stable State ◽  
Future Research ◽  
Regulation System ◽  
Engineering Practice ◽  
Sectional Area ◽  
Surge Tank ◽  
Power Stations ◽  
Pumped Storage ◽  
Hydropower Stations

The critical stable sectional area (CSSA) for surge tanks corresponds to the critical stable state of hydropower stations and is an important index to evaluate the stability of the turbine regulation system. The research on CSSA for surge tanks is always one of the most important topics in the area of transient processes of hydropower stations. The CSSA for surge tanks provides the value basis for the sectional area of surge tanks. In engineering practice, the CSSA for surge tanks is widely used to guide their hydraulic design. This paper provides a systematic literature review about the CSSA for surge tank of hydropower stations. Firstly, the CSSA for surge tanks based on hydraulic transients is discussed. Secondly, the CSSA for surge tanks based on hydraulic-mechanical-electrical coupling transients is presented. Thirdly, the CSSA for air cushion surge tanks is illustrated. Finally, the CSSA for combined surge tanks, i.e., upstream and downstream double surge tanks and upstream series double surge tanks, is presented. In future research, the CSSA for surge tanks of pumped storage power stations should be explored. The CSSA for surge tanks considering multi-energy complement is worth studying.

Research and Optimization of Thermal Power Unit's Automatic Control Based on Frequency Regulation Ability of Power Grid

2013 ◽  
Vol 330 ◽  
pp. 606-610 ◽  
Author(s):  
Jun Li ◽  
Wei Wei Li
Keyword(s):  
Power Systems ◽  
Automatic Control ◽  
Power Grid ◽  
Thermal Power ◽  
Optimal Operation ◽  
Theory And Practice ◽  
Frequency Regulation ◽  
Frequency Compensation ◽  
The Stability ◽  
Primary Frequency

Wind power and other new energy connected to power grid bring new challenges to optimal operation of power systems. The stability of power grid mainly depends on primary frequency compensation and secondary frequency compensation of thermal power units. By analyzing the theory and practice of DEH and coordinated control system (CCS) of thermal power units, combined with the insufficient of actual primary frequency compensation and automatic power generation control (AGC) strategy response to frequency of accidents, the optimization of primary frequency compensation and AGC of thermal power units automatic control were offered. The practical application results show that the proposed control strategy can effectively control the thermal power units to achieve the stability of power grid frequency.

Reliability Evaluation for the Main Electrical Wiring of Pumped-Storage Power Station Based on the GO Methodology

2014 ◽  
Vol 1030-1032 ◽  
pp. 574-578 ◽  
Author(s):  
Fu Liang Deng ◽  
Hai Sheng Liu ◽  
Shao Chen Wu
Keyword(s):  
Power Grid ◽  
Original Data ◽  
Reliability Evaluation ◽  
Power Station ◽  
Evaluation Indexes ◽  
Existing Problems ◽  
Go Methodology ◽  
Electrical Wiring ◽  
Pumped Storage ◽  
First Time

This paper introduced the function of the Pumped-Storage Power Station in power grid and the significance of reliability evaluation. Based on the principle of the GO method, the main electrical wiring’s reliability of the pumped-storage power station is proposed for the first time. According to the original data in references, the GO chart is established and the reliability is calculated and analyzed and evaluation indexes are put forward. The results show that the method is feasible. Finally it expounds the existing problems and shortcomings.

Wind, Thermal and Hydropower Joint Operation Benefit Analyzes Based on the Life Cycle Management

2014 ◽  
Vol 496-500 ◽  
pp. 2720-2724
Author(s):  
Zhong Fu Tan ◽  
Lei Sun ◽  
Huan Huan Li ◽  
Li Wei Ju ◽  
Zhi Hong Chen
Keyword(s):  
Wind Power ◽  
Cost Benefit Analysis ◽  
Power Grid ◽  
Thermal Power ◽  
Cost Benefit ◽  
Generation Process ◽  
Analysis Model ◽  
Power Station ◽  
Grid Connection ◽  
Pumped Storage

Aimed to solve the abandoned wind problem and reduce CO2 emission in the power generation process, this paper put forward a thermal, wind power and pumped storage power station co-operation cost-benefit analysis model. And through a simulation example, found that using pumped storage power station to substitute thermal power as the alternate service for wind power, and absorb underused wind power, can reduce the use of fired units and increase the capacity of grid to absorb wind power, as well as reduce CO2 emission. Then through the sensitivity analysis, found that the amount of grid-connected wind power is a sensitive factor of CO2 emission reduction and the decrease of grid power purchase profit. So when grid implementing wind power grid connection, should use pumped storage power station as the wind power alternate service to promote wind power grid connection.

scholarly journals Nonlinear Modeling of Dynamic Characteristics of Pump-Turbine

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 297
Author(s):  
Liying Wang ◽  
Kaidi Zhang ◽  
Weiguo Zhao
Keyword(s):  
Linear Model ◽  
Nonlinear Model ◽  
Dynamic Characteristics ◽  
Clean Energy ◽  
Energy Development ◽  
Stable Operation ◽  
Storage Unit ◽  
Pump Turbine ◽  
Characteristic Model ◽  
Pumped Storage

Hydropower is a kind of clean energy, which can effectively reduce the consumption of fossil energy and is one of the main fields of new energy development. Pumped storage power station not only provides a solution for storing electric energy and generating excess, but also is a clean, efficient, economical and safe power system regulation method with high quality. Accurate modeling of a pump-turbine, as the core equipment of a pumped storage unit, is the key to safe and stable operation of the pumped storage unit. At present, a method of simplifying the external characteristics of a pump-turbine into a first-order linear model is widely used, which cannot effectively and accurately reveal the nonlinear dynamic characteristics of the unit in transition process. In order to meet the demand of high-precision simulation of the unit, a new method of identifying Taylor series expansion considering nonlinearity based on the torque characteristic formula and the flow characteristic formula is proposed, which is applied to the pump-turbine external characteristic model, and retains the second derivative term, making the model a second-order nonlinear model, and thus, the pump-turbine model becomes a nonlinear model. The nonlinear model established is used to simulate the load increase and load rejection of the unit, and the results are compared with those for the linear model. The comparison shows that the nonlinear model established for the pump-turbine can reveal the dynamic response of the unit more effectively and accurately than the linear model, and provide a further guarantee for the safe and stable operation of pumped-storage units, which is of great significance to hydropower energy development.

scholarly journals Adaptive Droop Coefficient and SOC Equalization-Based Primary Frequency Modulation Control Strategy of Energy Storage

Electronics ◽  
2021 ◽  
Vol 10 (21) ◽  
pp. 2645
Author(s):  
Gaojun Meng ◽  
Yang Lu ◽  
Haitao Liu ◽  
Yuan Ye ◽  
Yukun Sun ◽  
...  
Keyword(s):  
Energy Storage ◽  
Frequency Modulation ◽  
Control Strategy ◽  
Simulation Analysis ◽  
Power Grid ◽  
Frequency Regulation ◽  
Storage Battery ◽  
Load Disturbance ◽  
Modulation Control ◽  
Primary Frequency

In order to efficiently use energy storage resources while meeting the power grid primary frequency modulation requirements, an adaptive droop coefficient and SOC balance-based primary frequency modulation control strategy for energy storage is proposed. Taking the SOC of energy storage battery as the control quantity, the depth of energy storage output is adaptively adjusted to prevent the saturation or exhaustion of energy storage SOC. The balanced control strategy is introduced to realize the rational utilization of resources and the fast balance of SOC in the process of primary frequency modulation of energy storage battery under different charge states. Then, four evaluation indexes are proposed to evaluate the effect of primary frequency modulation and SOC maintenance. Taking a regional power grid as an example, a simulation analysis is carried out under step load disturbance and continuous load disturbance. According to the simulation results, the proposed control strategy is effective in power system frequency regulation and battery SOC maintenance.

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