scholarly journals Analysis of the Implementation of the Primary and/or Inertial Frequency Control in Variable Speed Wind Turbines in an Isolated Power System with High Renewable Penetration. Case Study: El Hierro Power System

Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 901 ◽  
Author(s):  
Guillermo Martínez-Lucas ◽  
José Ignacio Sarasúa ◽  
Juan Ignacio Pérez-Díaz ◽  
Sergio Martínez ◽  
Danny Ochoa

With high levels of wind energy penetration, the frequency response of isolated power systems is more likely to be affected in the event of a sudden frequency disturbance or fluctuating wind conditions. In order to minimize excessive frequency deviations, several techniques and control strategies involving Variable Speed Wind Turbines (VSWTs) have been investigated in isolated power systems. In this paper, the main benefits and disadvantages of introducing VSWTs—both their inertial contribution and primary frequency regulation—in an exclusively renewable isolated power system have been analyzed. Special attention has been paid to the influence of the delays of control signals in the wind farm when VSWTs provide primary regulation as well as to the wind power reserve value which is needed. To achieve this objective, a methodology has been proposed and applied to a case study: El Hierro power system. A mathematical dynamic model of the isolated power system, including exclusively renewable technologies, has been described. Representative generation schedules and wind speed signals have been fixed according to the observed system. Finally, in order to obtain conclusions, realistic system events such as fluctuations in wind speed and the outage of the generation unit with the higher assigned power in the power system have been simulated.

Author(s):  
Clemens Jauch ◽  
Arne Gloe

This paper presents findings of a study on continuous feed-in management and continuous synthetic inertia contribution with wind turbines. A realistic case study, based on real measurements, is outlined. A wind turbine feeds into a weak feeder, such that its power has to be adapted to the permissible loading of this feeder. At the same time the wind turbine is to provide inertia to the grid by applying the previously published variable inertia constant controller. It is discussed that optimal grid utilisation and simultaneous inertia contribution are mandatory for the frequency control in power systems that are heavily penetrated with renewable energies. The study shows that continuous feed-in management can be combined well with continuous inertia provision. There are hardly any negative consequences for the wind turbine. The benefits for the grid are convincing, both in terms of increased system utilisation and in terms of provided inertia. It is concluded that wind turbines can enhance angular stability in a power system to a larger extent than conventional power plants.


2012 ◽  
Vol 608-609 ◽  
pp. 579-583
Author(s):  
Yao Fei Hou ◽  
Guang Kai Li ◽  
Jian Ding ◽  
Jie Shen ◽  
Song Teng

The variable-speed doubly-fed wind turbines (DFIG) were able to participate in frequency regulation by adding an additional frequency control. The influences exerted by the additional frequency control of DFIG units and conventional units governors on system frequency emergency control measures were analyzed. When the power shortage is small, it is recommended to consider the DFIG units to participate in frequency regulation, While a large power shortage it is not recommended.


Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2865 ◽  
Author(s):  
José Sarasúa ◽  
Guillermo Martínez-Lucas ◽  
Carlos Platero ◽  
José Sánchez-Fernández

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.


Author(s):  
Semaria Ruiz ◽  
Julian Patiño ◽  
Jairo Espinosa

<pre>The increasing use of renewable technologies such as wind turbines in power systems may require the contribution of these new sources into grid ancillary services, such as Load Frequency Control. Hence, this work dealt with the performance comparison of two traditional control structures, PI and <span>LQR</span>, for secondary regulation of Load Frequency Control with the participation of variable-speed wind turbines. For this purpose, the doubly-fed induction generator wind turbine was modeled with additional control loops for emulation of the inertial response of conventional machines for frequency regulation tasks. Performance of proposed strategies was verified through simulation in a benchmark adapted from the <span>WSCC</span> 3 machines 9-bus test system. Results showed overall superior performance for <span>LQR</span> controller, although requiring more strenuous control effort from conventional units than PI control.</pre>


Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 3013 ◽  
Author(s):  
Clemens Jauch ◽  
Arne Gloe

This paper presents findings of a study on continuous feed-in management and continuous synthetic inertia contribution with wind turbines. A realistic case study, based on real measurements, is outlined. A wind turbine feeds into a weak feeder, such that its power has to be adapted to the permissible loading of this feeder. At the same time the wind turbine is to provide inertia to the grid by applying the previously published variable inertia constant controller. It is discussed that optimal grid utilization and simultaneous inertia contribution are mandatory for the frequency control in power systems that are heavily penetrated with renewable energies. The study shows that continuous feed-in management can be combined well with continuous inertia provision. There are hardly any negative consequences for the wind turbine. The benefits for the grid are convincing, both in terms of increased system utilization and in terms of provided inertia. It is concluded that wind turbines can enhance angular stability in a power system to a larger extent than conventional power plants.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3660
Author(s):  
Danny Ochoa ◽  
Sergio Martinez

The significant presence of variable-speed wind turbines in worldwide power systems has led to planners and grid operators requiring them to participate in frequency control tasks. To address this demand, a large number of wind frequency control proposals have been reported in the literature in recent years. Many of these solutions have been tested by specific experiments carried out in computer simulation environments. This paper proposes a methodology to evaluate the effects of enabling frequency support by wind turbines on the magnitudes that characterize the inertial response of a power system by using an analytical approach. The derived formulation and the illustrations are designed to provide a better understanding of both the mechanisms that determine the frequency stability indices and the improvement achieved by enabling the inertial response of wind turbines by implementing a virtual inertia-based method on the active power controllers of these machines. To facilitate the comprehension of the results obtained, the analytical approach is complemented with time-domain simulations in a predefined test system implemented in MATLAB/Simulink®. The proposed methodology achieves a generalization of the results and can be used for the assessment of any power system configuration.


Author(s):  
Issam Minka ◽  
Ahmed Essadki ◽  
Sara Mensou ◽  
Tamou Nasser

<span lang="EN-US">In this paper, we study the primary frequency control that allows the variable speed Aeolian to participate in the frequency regulation when a failure affects the network frequency. This method based on the control of the generator rotational speed or the control of pitch angle makes it possible to force the wind turbine to produce less power than its maximum available power, consequently we will create an active power reserve. This wind turbine must inject into the grid a part of its power reserve when the frequency drops, in contrary the wind turbine reserves more of energy. So, this work presents the performances of this control strategy for the different wind speed value. The results are obtained by a simulation in the MATLAB/SIMULINK environment.</span>


2021 ◽  
Vol 9 ◽  
Author(s):  
Qi Zhu ◽  
Yingjie Wang ◽  
Jiuxu Song ◽  
L. Jiang ◽  
Yingliang Li

Frequency stability of the power system is impacted by the increasing penetration of wind power because the wind power is intermittent. Meanwhile, sometimes the demand side loads increase quickly to require more power than total power produced. So balancing the active power in the power system to maintain the frequency is the main challenge of the high penetration of wind power to the smart grid. This paper proposes coordination rotor speed control (RSC), pitch angle control (PAC) and inertial control (IC) to control wind turbines, together with demand side response (DSR) participating in frequency regulation to balance active power in the power system. Firstly, the model of a single area load frequency control (LFC) system is obtained, which includes variable-speed wind turbines (VSWT) and DSR containing aggregated air conditioners and plug-in electric vehicles (PEVs). Then the RSC, PAC and IC, which controls wind turbines participating in frequency regulation in the power system, are introduced, respectively. Finally, the coordination of these three methods for wind turbines in different wind speeds is proposed. Case studies are carried out for the single area LFC system with a wind farm and DSR supported grid frequency. Coordination RSC and PAC combined IC are used to control wind turbines with DSR to balance active power in the power system. The proposed method used in the power system with high penetration of wind power and fluctuation of demand load is tested, respectively. Coordinated RSC or PAC with DSR can increase penetration of wind power and reduce peak load.


2021 ◽  
Vol 16 ◽  
pp. 204-212
Author(s):  
Minh-Hoa Nguyen ◽  
Van-Tan Tran ◽  
Tan-Hung Pham ◽  
Thanh-Luu Cao

Renewable energy is an emerging candidate in power generation for the compensation of the exhausted fossil fuel, in which wind energy plays an important role. However, how wind farms impact existing power systems has still been a subject on which many researchers are studying. This study has analyzed and evaluated the four wind farms consisting of Ca-Mau (300 MW), Bac-Lieu (99 MW), Soc-Trang (100 MW) and Tra-Vinh (33 MW) located in Southern Vietnam via using the commercial package, WAsP software. Ca-Mau wind farm has the highest planned rated capacity with 51.7% among the wind farms. Each wind farm is built from three different types of wind turbines (1 MW, 2 MW and 3 MW). The estimation has shown that all of the wind farms could produce 2,265 GWh annually, and the 3-MW wind turbines are the most efficient and give the smallest losses for producing wind energy. The wind farms, with respect to environmentally friendly aspects, could avoid 978,544 tCO2 emitted to the environment annually. Additionally, the ETAP program has also been applied to simulate the effects of the proposed wind farms on the national power system including the disturbances from wind speeds, three-phase bus faults, tripping off wind farms and three-phase line faults on the power system. The results show that the wind farms are only slightly impacted.


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