Output Power Of Wind Turbine Generators Research Articles

Optimizing Production of Kwh Legon PLTD PLTD Using Wind Turbine Generator Model B. Ventus 250 KW(Case Study on Karimunjawa Island)

Electricity supply must be able to reach all users, including those on small islands in Indonesia, one of which is Karimunjawa Island. Starting in 2016 Karimunjawa Island is supplied by 2 units of Legon Bajak Diesel Power Plant (PLTD) with a capacity of 2x2.2 MW. Based on the peak electricity demand on Karimunjawa Island, each month from January 2017 to December 2018 increased by about 3.9% with an hourly peak load of 1,146 kWh. The average consumption of PLTD Legon Bajak every month in 2018 is 194,877 liters / month. The higher the kWh production of a PLTD, the higher the operational costs for fuel. In addition to the high price of fuel, combustion results from PLTD operations also cause air pollution. Based on these problems in this study will analyze the optimization of the kWh Legon Bajak PLTD using a wind turbine generator model b.ventus 250 kW of 3 units with an assumption of 50% of the peak load, because on Karimunjawa Island has a high enough wind energy potential. The average wind speed from 2004 to 2015 in several areas of Karimunjawa Island was 5.7 m / s. In this study will calculate technical analysis and economic analysis. In the technical analysis the wind turbine generator power output is calculated using the weibull method based on wind speed and power curve b.ventus 250 kW while the economic analysis calculates the cost of fuel savings that can be achieved after optimization calculations. Calculation results show wind turbine power output of 990,981 kWh / year. Based on the specific value of fuel consumption (SFC) of 0.432 liters / kWh fuel consumption during 2017 amounted to 1,605,453.9 liters / year while for 2018 it was 2,338,528.1 liters / year. From the 3 wind turbine electricity supply of 2,972,943 kWh / year, it will reduce fuel consumption by 1,284,311.4 liters / year with a saving cost of Rp.15,989,291,338.00. The amount of optimization of the kWh PLTD after the supply of 3 units of b.ventus 250 kW wind turbine model in 2017 was 80% while in 2018 it was 54.9%.

Optimal constant power control of wind turbine generators based on Takagi-Sugeno fuzzy model

Resource shortages and environmental pollution of the world are becoming more and more serious, wind Turbine generation as a kind of clean energy power generation has attracted much attention. The difficulty of wind power generation lies in the randomness of natural wind energy, which leads to the instability of the output power of Wind Turbine Generators (WTGs). The traditional variable pitch controller cannot realize global precision control of the wind power system. To solve the problem, this paper combines Takagi-Sugeno (T-S) fuzzy model with optimal control theory to design a robust controller. The unique novelty of the controller is that when the wind speed is higher than the rated, no matter how much the wind speed is, even if it is far from the balance point of the system, the controller can make the output power at a constant value, that is, increase the global stability of the wind power system. Specifically, the wind power system was divided into several linear subsystems, and the state feedback controller of each subsystem was designed through optimal control. Then, the subsystem controllers were merged by superposing membership functions, forming a controller of the entire system. Finally, wind turbine generators (WTGs) were modeled and simulated in Matlab/Simulink. The results show that the proposed controller kept the output power of WTGs constant under the global step wind of 13–25 m/s and the stochastic wind of 14–15 m/s. Our design enables the precision control at any wind speed, and improves the stability of power output of WTGs.

Improving Power Harvesting Ability of Variable Speed Wind Turbine using Intelligent Soft Computing Technique

This paper presents a study carried out on maximizing energy harvesting of wind turbines. One way of improving the output power of the wind turbines is by optimizing the power conversion coefficient. The power conversion coefficient factor is expressed as a function of the wind turbine blade tip speed ratio and the turbine blade pitch angle. Optimization of the wind turbine generator output power is done by considering the effects of variations of wind speed, blade tip speed ratio, and pitch angle. An intelligent soft computing technique known as an adaptive neuro-fuzzy inference system (ANFIS) with a fuzzy logic controller for blade pitch actuator was applied to optimize the generator output power. The simulation result showed that the power conversion coefficient of 0.513 is achieved. The study was verified by using real-time wind speed data of Adama II wind farm in Ethiopia and specifications of the Gamesa G80 horizontal axis wind turbine generator unit by MATLAB software. Accordingly, a promising and satisfying improvement in power harvesting capacity is obtained. The output power of this generator is improved by 9.47% which is by far better result as compared to the existing literature.

Economic power control for offshore wind farms with loop connection cables

Abstract The Canadian developer and owner of green power facilities Northland Power Inc. owns two offshore wind farms (OWFs) in the German Bight, Deutsche Bucht and Nordsee One, operated by the subsidiary Northland Power Europe GmbH. The company supports and conducts research in the field of power flow optimization in wind farm networks. The work at hand represents the results of this effort to maximize the efficiency of the assets. The project was accomplished within a cooperation between the Nordsee One GmbH and the Institute of Electrical Power and Energy Technology at the Hamburg University of Technology. From an external point of view, an OWF represents an “en bloc” power plant connected to the onshore transmission grid via power export cables. Nevertheless, such a power plant comprises a complex, large-scale internal medium voltage network. In case of failure or cable outage, the network topology of an OWF may be modified and unintended overloading of inter-array cables (IACs) is possible. In order to address this issue, a new algorithm and software tool for economic power control in OWFs are introduced in the following which can be employed in wind farms with integrated loop connection cables (LCCs). This configuration particularly entails the risk of overloading cable segments depending on the present wind speed. The new algorithm provides the operator with adapted active power setpoints for each wind turbine generator (WTG) in a given network topology. The aim is to maximize OWF power generation and minimize internal power losses while secure network operation is guaranteed. Using load flow analysis based on WTG power output measurements, the load on each cable section is monitored and the cables can be utilized to their individual full capacity while overload is avoided. The practicability of the approach is demonstrated by means of simulation results.

Power Smoothing of a Variable-Speed Wind Turbine Generator Based on a Two-Valued Control Gain

This article proposes a power-smoothing scheme for a variable-speed wind turbine generator (WTG) that can maintain the frequency within a narrow range under normal operations. The proposed scheme uses an additional control loop based on the frequency deviation that operates in conjunction with maximum power point tracking (MPPT). To improve the energy-absorbing capability in the overfrequency section (OFS) and energy-releasing capability in the underfrequency section (UFS), the scheme suggests separate control gains, which are determined based on the ratio of the output of the additional loop to that of the MPPT loop. The ratio in the OFS is set to decrease with respect to the rotor speed whereas the ratio in the UFS is set to increase with respect to the rotor speed. The simulation results demonstrate that the proposed scheme can significantly lessen the WTG output power fluctuations by adjusting the control gains of the UFS and the OFS even though the WTG output power is severely fluctuating, thereby mitigating the frequency fluctuations. The scheme effectively uses the heavy rotating masses of a WTG as an energy storage system for enhancing the power grid flexibility in terms of frequency, particularly in high penetration levels of variable renewable energy.

공급신뢰도 측면에서의 신재생에너지발전단지와 연계된 BESS의 운용 알고리즘 개발

This paper proposes a probabilistic reliability evaluation model and algorithm for the power system considering wind turbine generator (WTG) and battery energy storage system (BESS) in viewpoint of power system reliability. A large-scale wind turbine generator (WTG) can creates significant power fluctuations and should affect the stability, frequency control and then reliability of the power system. Therefore, wind power should be limited to supply the percentage of load. The output of WTG cannot be predicted accurately and so results in significant fluctuations in power supply balance. Therefore, it is difficult to control the power balance between supply and demand. However, it can be controlled by installing the BESS. The BESS may smooth the fluctuation of the WTG power output. This paper proposes reliability based alternative algorithm in order to simulate the effects of the interaction of multiple WTG and BESS newly. Additionally, this paper presents sample system studies that single BESS as well as multi-BESS are simulated by handwork very clearly. Futhermore, the reliability effects of BESS according to a couple of different BESS operation rules and conditions are demonstrated in sample system case study.

Multi-Objective Optimization for Determining Trade-Off between Output Power and Power Fluctuations in Wind Farm System

In this paper, a multi-objective optimization method is proposed to determine trade-off between conflicting operation objectives of wind farm (WF) systems, i.e., maximizing the output power and minimizing the output power fluctuation of the WF system. A detailed analysis of the effects of different objective’s weight values and battery size on the operation of the WF system is also carried out. This helps the WF operator to decide on an optimal operation point for the whole system to increase its profit and improve output power quality. In order to find out the optimal solution, a two-stage optimization is also developed to determine the optimal output power of the entire system as well as the optimal set-points of wind turbine generators (WTGs). In stage 1, the WF operator performs multi-objective optimization to determine the optimal output power of the WF system based on the relevant information from WTGs’ and battery’s controllers. In stage 2, the WF operator performs optimization to determine the optimal set-points of WTGs for minimizing the power deviation and fulfilling the required output power from the previous stage. The minimization of the power deviation for the set-points of WTGs helps the output power of WTGs much smoother and therefore avoids unnecessary internal power fluctuations. Finally, different case studies are also analyzed to show the effectiveness of the proposed method.

Optimal Operation of Wind Farm for Reducing Power Deviation Considering Grid-Code Constraints and Events

In wind farm (WF) systems, the set-points of wind turbine generators (WTGs) is determined by the wind farm operator. A change in the value of set-point in two consecutive intervals leads to power fluctuations in the WF system, i.e. power deviation. A large amount of power deviation may adversely affect the operation of the WF system. Therefore, this paper proposes a strategy for operation of a WF system to minimize the power deviation of WTGs during operation time. By using the proposed strategy, the change in set-points of WTGs is minimized and the output power of WTGs is therefore smoother and avoids unnecessary fluctuations. Several grid-code constraints are also considered for operation of the WF system. This ensures the WF system to operate in compliance with the requirements from transmission system operator. Besides, an additional strategy is also proposed to monitor all events in the WF system. Whenever an event occurs in the system, the set-points of WTGs are rescheduled considering the event. Therefore, the proposed operation strategy is also capable of handling events in the WF system. Finally, the simulation results with and without the proposed method are compared to show the effectiveness of the proposed method.

Frequency Control of Isolated Wind-Diesel Microgrid Power System by Double Equivalent-Input-Disturbance Controllers

In a wind-diesel isolated microgrid, the fluctuating output power of wind turbine generator (WTG) and the perturbation of the load demand will lead to power imbalance and frequency deviation in the system. Appropriate frequency control schemes are indispensable to guarantee power quality through maintaining the power balance. In view of the outstanding performance of Equivalent-Input-Disturbance (EID) method, it is taken to the task of load frequency control (LFC) problem of this microgrid. In this paper, novel double EID controllers are proposed for the frequency control of a wind-diesel isolated microgrid. In this integrated control design, one single EID controller is applied to the pitch angle control system to smooth output power of WTG by controlling the pitch angle. At the diesel generator side, another single EID controller is applied to adjust the output power of the diesel generator to maintain the power balance of the system and finally preserve frequency in the normal range. Battery energy storage system is connected as auxiliary regulation. The simulation studies show superior flexibility and control performance of the proposed strategy compared to the conventional PI method in a wind-diesel isolated microgrid in MATLAB.

The Coordinated Control of Wind-Diesel Hybrid Micro-Grid Based on Sliding Mode Method and Load Estimation

In order to reduce the frequency deviation resulting from renewable energy fluctuation and load variance, the coordination control strategy for isolated wind-diesel hybrid micro-grid is proposed by taking advantage of smart neural network observer and sliding mode method. For diesel generator system side, the sliding mode load frequency control including load variance is designed to regulate the output power. For the wind turbine generator system side, the sliding mode pitch angle control considering load variance is constructed to smooth the wind turbine generator output power fluctuation. Furthermore, the different coordinated strategies are proposed to realize the plug and play for the hybrid micro-grid, it is easy to see that the control accuracy can be improved by the designed neural network adaptive observer and considering the load variation. The effectiveness of the proposed control strategy is validated through real time digital simulator platform under different operation condition.

Control Strategies for Enhancing Frequency Stability by DFIGs in a Power System with High Percentage of Wind Power Penetration

Nowadays, regarding high percentage of wind power penetration in power systems, operating conditions of power system necessitates wind turbine generators (WTGs) to contribute in frequency regulation of the system, similar to the conventional units. To reach this goal, active power output of WTGs must be controlled, but this issue distances the operating conditions of WTGs from maximum power point tracking (MPPT) mode. This paper initially presents a completed model of doubly fed induction generator (DFIG) for dynamic studies in frequency stability analysis. Next, a coordinated control strategy to regulate active power command set point (Pcmd) for individual WTGs in a wind farm (WF) and a control strategy to regulate wind power output of DFIG upon operator’s request is presented. Stability is assured under different wind conditions in the proposed control strategy. Individual WTGs set point allocation is performed applying fuzzy logic controller (FLC), while emotional learning based intelligent controller is used in regulation of the coefficient in the DFIG to reach the best stability conditions. Simulation results, performed on a test system consisting of both conventional units and WTGs, validate the effectiveness of the proposed control strategy in comparison with other mentioned solutions.

Optimal allocation of wind turbine generator in active distribution network

Nowadays, more and more wind turbine generators (WTGs) are being integrated into power systems. In this paper, an optimal WTG allocation model with the objective of minimizing the annual cost is proposed. The model can take into account the time‐sequential correlation between the wind speed and load demand, as well as four kinds of active management measures, i.e. regulating the on‐load tap changer of the transformer, curtailing the output power of WTG, regulating the power factor of WTG, and managing the demand side. The time‐sequential correlation is handled by the joint probability distribution method. A hybrid solving strategy combining the fuzzy adaptive particle swarm optimization algorithm and primal‐dual interior point method is developed to get the optimal solutions. Case studies carried out on the IEEE 33‐bus active distribution network verify the feasibility of the developed model and the high efficiency of the proposed solving strategy. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Stepwise Inertial Control of a Doubly-Fed Induction Generator to Prevent a Second Frequency Dip

To arrest a frequency nadir, a stepwise inertial control (SIC) scheme generates a constant active power reference signal of a wind turbine generator (WTG) immediately after a disturbance and maintains it for the predetermined time. From that point, however, the reference of a WTG abruptly decreases to restore the rotor speed for the predefined period. The abrupt decrease of WTG output power will inevitably cause a second frequency dip. In this paper, we propose a modified SIC scheme of a doubly-fed induction generator (DFIG) that can prevent a second frequency dip. A reference value of the modified SIC scheme consists of a reference for the maximum power point tracking control and a constant value. The former is set to be proportional to the cube of the rotor speed; the latter is determined so that the rotor speed does not reach the minimum operating limit by considering the mechanical power curve of a DFIG. The performance of the modified SIC was investigated for a 100 MW aggregated DFIG-based wind power plant under various wind conditions using an EMTP-RV simulator. The results show that the proposed SIC scheme significantly increases the frequency nadir without causing a second frequency dip.

Optimal siting and sizing of intermittent distributed generators in distribution system

Intermittent distributed generators (IDGs), such as distributed wind turbine generator (WTG) and photovoltaic generator (PVG), have been developing rapidly in recent years. The output power of WTG and PVG highly depends on the wind speed and illumination intensity, respectively. There always exist correlations among the wind speed, illumination intensity, and bus load, which could have significant influence on the determination of siting and sizing of IDGs in distribution system. Given this background, a chance‐constrained‐programming‐based IDGs planning model, which can take into account the correlations, is developed in this paper. Latin hypercube sampling technique and Cholesky decomposition are introduced to handle the correlations. A Monte Carlo simulation‐embedded multi‐population differential evolution algorithm is employed to solve the developed model. Case studies carried out on the Baran & Wu 33‐bus distribution system verify the feasibility of the developed model and effectiveness of the proposed solving methodology. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

English

Due to the nature of unpredicted wind speed, determining the optimal speed of wind turbine generator to extract the maximum available wind power at any wind speed is essential. By controlling the pitch angle of the wind turbine blades we can control the rotational speed and the output power. To get the maximum output power under lower wind speed and to maintain the stable rated output power under higher wind speed, the proper method must be used. In this paper, particle swarm optimization (PSO)-based maximum power point tracking (MPPT) algorithm is used to trace the maximum power when wind speed is lower than the rated speed and to get the proper pitch angle to limit the output power when the wind speed is greater than the rated speed. The simulation results performed on MATLAB/Simulink show the variations of the wind turbine generator output power, rotor speed, torque, pitch angle of wind turbine blades and wind velocities at those instants.

제주도 계통에서의 풍력발전기 및 ESS를 고려한 신뢰도 평가

This paper proposes probabilistic reliability evaluation model of power system considering Wind Turbine Generator(WTG) integrated with Energy Storage System(ESS). Monte carlo sample state duration simulation method is used for the evaluation. Because the power output from WTG units usually fluctuates randomly, the power cannot be counted on to continuously satisfy the system load. Although the power output at any time is not controllable, the power output can be utilized by ESS. The ESS may make to smooth the fluctuation of the WTG power output. The detail process of power system reliability evaluation considering ESS cooperated WTG is presented using case study of Jeju island power system in the paper.

Energy Management System for Stand-Alone Wind-Powered-Desalination Microgrid

An energy management system for stand-alone microgrid consisting of a wind turbine (WT) generator, a diesel generator, an energy storage system (ESS), and a sea water desalination system is proposed in this paper. The coordinated control of the distributed generations and ESS is researched with two operation modes. Then, a real-time rolling horizon energy management method is presented based on hour-ahead wind speed forecast. The operation mode of the microgrid system and the reference output power of WT generator are determined according to the forecasted wind speed and state of charge of the ESS, which can achieve the goal of maximizing utilization of wind energy and minimizing utilization of diesel generator on the basis of system stable operation. The proposed energy management method has been tested on the real-time digital simulator system. The results clearly verify the effectiveness of the proposed method.

Application of Stochastic Simulation Method in Reliability Assessment of a PV-Wind-Diesel-SOFC Hybrid Microgrid

 Abstract—In this paper, the sequential monte carlo simulation method is used to obtain the reliability indices of an isolated hybrid microgrid consist of diesel generator (DG), solid oxide fuel cell (SOFC), wind turbine generator (WTG), and photovoltaic system (PV). Some atmospheric data such as wind speed, solar irradiation, and ambient temperature data are used to achieve the output power of WTG and PV systems which can be obtained by two method; collecting data from weather station or using the computer programs. For this purpose, Weibull distribution is used. To obtain the adequacy model of DG and SOFC, a two state reliability model is used. A combination of this model and output power formulation is also used to achieve the generation model of WTG, and PV systems. Furthermore, the total generation model is compared with IEEE reliability test system (IEEE RTS) load model and the reliability indices are then achieved, which show the effectiveness of the SMCS method in reliability evaluation of both stable and unstable resources like WTG and PV. In this paper, a microgrid including some renewable energy supplies such as PV, WTG, SOFC, and DG with different configurations are studied to evaluate the system reliability indices. To model DG and SOFC, a two-state model is employed. To model the availability of PV and WTG, a combination of the two-state model and their inherent characteristics should be used. To evaluate the microgrid reliability indices, the IEEE RTS load model (9) is compared with the developed generation model. There are two reliability evaluation approaches: deterministic and probabilistic (10). The deterministic approaches cannot identify the random behavior of the microgrid systems. To calculate the reliability indices of both stable and unstable resources like WTG and PV, the generation and load models are applied to the sequential MCS, as a probabilistic approach. The work in this study is organized as follows: in Section 2, the electrical output power of wind system is modelled. The delivered output power of the PV system is formulated in Section 3. The adequacy assessment methodology of the microgrid system is introduced in Section 4 consist of microgrid generation and the load demand models. Section 5 is dedicated to present some case studies. Conclusion and future considerations are summarized in the last section of the paper.

Tired of Continuous Time-Series Analysis or Calculations?

A novel analytical approach of reliability evaluation for a wind-diesel hybrid power system with a battery bank for power supply in the remote areas is proposed in this article. This approach is developed on the basis of the discrete wind-speed frame analysis of the Weibull wind-speed distribution. Using the wind-speed frame analysis, an analytical model of a wind-diesel hybrid system is developed, which deals with the system outage as a result of component failure and wind-speed fluctuation. This model computes a power output of wind-turbine generators (WTGs) for each discrete wind-speed frame, which is created by splitting the Weibull wind-speed distribution curve. Then, a battery bank model is combined with that of the wind-diesel system. The reliability analysis of the overall system is conducted by combining power outputs of the wind and diesel generation units with battery throughout all wind-speed frames. This is done to obtain the reliability indices, loss of load probability (LOLP), and expected energy not supplied (EENS), which reflect a long-term performance of the hybrid power system. Using the wind-speed frame, the intermittent characteristics of wind speed and turbine failure can be easily taken into account. Simultaneously, the modeling process can be greatly simplified, and the calculation time can be saved. This model is suitable for the system reliability assessment for both system planning and system optimization.

A New Stand-Alone Hybrid Power System with Wind Turbine Generator and Photovoltaic Modules for a Small-Scale Radio Base Station

This paper proposes a new stand-alone hybrid power system with a wind turbine generator and photovoltaic modules for a small-scale radio base station. We studied the system characteristics by simulation of operation on Yonaguni Island, where wind speed exceeds 4.0m/s throughout the year, and average annual wind speed is about 7.0m/s. The results of simulation show that, to attain a system operation rate of 100%, the base station equipment requires a wind turbine generator output power of 8kW, a photovoltaic output power of 7.6kW, and 3-day backup storage batteries.