Microgrid modeling for contribution to the frequency control of power system

2021 ◽  
pp. 0309524X2110500
Author(s):  
Alireza Ghafouri

Recently, Distributed Energy Resources (DERs) are becoming more attractive to supply local loads under the concept of microgrids. These new parts of the power system have basically different dynamics compared with conventional power plants. Most of them are connected to the grid by power electronic interfaces, and their dynamic is determined by their controller. In this paper, the effect of the increased penetration of DERs on the load frequency problem of power systems is studied. The DERs of microgrids in each area are controlled to change their active power at Point of Common Coupling (PCC) after a disturbance in the power system. It is shown that with appropriate control of DERs in microgrids, the frequency deviation of the power system will decrease and the stability margin can be increased.

2018 ◽  
Vol 8 (2) ◽  
pp. 2633-2639 ◽  
Author(s):  
K. Soleimani ◽  
J. Mazloum

Power systems include multiple units linked together to produce constantly moving electric power flux. Stability is very important in power systems, so controller systems should be implemented in power plants to ensure power system stability either in normal conditions or after the events of unwanted inputs and disorder. Frequency and active power control are more important regarding stability. Our effort focused on designing and implementing robust PID and PI controllers based on genetic algorithm by changing the reference of generating units for faster damping of frequency oscillations. Implementation results are examined on two-area power system in the ideally state and in the case of parameter deviation. According to the results, the proposed controllers are resistant to deviation of power system parameters and governor uncertainties.


Author(s):  
Roghieh Abdollahi Biroon ◽  
Pierluigi Pisu ◽  
David Schoenwald

The increasing penetration of renewable energy sources in power grids highlights the role of battery energy stor- age systems (BESSs) in enhancing the stability and reliability of electricity. A key challenge with the renewables’, specially the BESSs, integration into the power system is the lack of proper dynamic model for stability analysis. Moreover, a proper control design for the power system is a complicated issue due to its complexity and inter-connectivity. Thus, the application of decentralized control to improve the stability of a large- scale power system is inevitable, especially in distributed energy sources (DERs). This paper presents an optimal distributed hybrid control design for the interconnected systems to suppress the effects of small disturbances in the power system employing utility-scale batteries based on existing battery models. The results show that i) the smart scheduling of the batteries’ output reduces the inter-area oscillations and improves the stability of the power systems; ii) the hybrid model of the battery is more user-friendly compared to the Western electricity coordinating council (WECC) model in power system analysis.


Author(s):  
Mahdi Karami ◽  
Norman Mariun ◽  
Mohd Amran Mohd Radzi ◽  
Gohar Varamini

Electric market always prefers to use full capacity of existing power system to control the costs. Flexible alternate current transmission system (FACTS) devices introduced by Electric Power Research Institute (EPRI) to increase the usable capacity of power system. Placement of FACTS controllers in power system is a critical issue to reach their maximum advantages. This article focused on the application of FACTS devices to increase the stability of power system using artificial intelligence. Five types of series and shunt FACTS controllers are considered in this study. Continuation power flow (CPF) analysis used to calculate the collapse point of power systems. Controlling parameters of FACTS devices including their locations are determined using real number representation based genetic algorithm (RNRGA) in order to improve the secure margin of operating condition of power system. The 14 and 118 buses IEEE standard test systems are utilized to verify the recommended method. The achieved results manifestly proved the effectiveness of proposed intelligent method to increase the stability of power system by determining the optimum location and size of each type of FACTS devices.


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.


Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5605
Author(s):  
Roghieh Abdollahi Biroon ◽  
Pierluigi Pisu ◽  
David Schoenwald

The increasing penetration of renewable energy sources in power grids highlights the role of battery energy storage systems (BESSs) in enhancing the stability and reliability of electricity. A key challenge with the renewables’, specially the BESSs, integration into the power system is the lack of proper dynamic models and their application in power system analyses. The control design strategy mainly depends on the system dynamics which underlines the importance of the system accurate dynamic modeling. Moreover, control design for the power system is a complicated issue due to its complexity and inter-connectivity, which makes the application of distributed control to improve the stability of a large-scale power system inevitable. This paper presents an optimal distributed control design for the interconnected systems to suppress the effects of small disturbances in the power system employing utility-scale batteries based on existing battery models. The control strategy is applied to two dynamic models of the battery: hybrid model and Western electricity coordinating council (WECC) model. The results show that (i) the smart scheduling of the batteries’ output reduces the inter-area oscillations and improves the stability of the power systems; (ii) the hybrid model of the battery is more user-friendly compared to the WECC model in power system analyses.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2288
Author(s):  
Zhenghao Wang ◽  
Yonghui Liu ◽  
Zihao Yang ◽  
Wanhao Yang

In recent years, wind power systems have been used extensively, which not only improve the efficiency of current conventional power generation systems, but also can save traditional fossil fuel resources. However, considering the instability of wind power, after being grid connected, it can easily cause an impact on the stability of the grid operation. Considering the above problems, this paper considers to make full use of the energy storage part of electric vehicles (EVs) to increase the stability of grid operation. Based on the mathematical model, this paper studies the load frequency control (LFC) problem of a multi-region interconnected power system with wind power and EVs. First, since the system states are difficult to be monitored, a state observer is designed to estimate the state. Based on this, the integral sliding mode controller (SMC) is designed to realize the LFC of the interconnected power system. Meanwhile, to obtain better control performance, this paper further analyzes and optimizes the controller parameters based on Lyapunov stability theory. At last, simulations are carried out for the power systems with two regions in Simulink. The results show that the designed controllers are effective to compensate the load demand disturbances. In addition, it is demonstrated that the battery storage of EVs can play the role of peak-shaving and valley-filling in LFC.


2019 ◽  
Vol 7 (1) ◽  
pp. 36-44
Author(s):  
Jorge Andrés Pérez ◽  
Ellis Moisés Reyes ◽  
Tannia Karina Vindel

The ancillary services are essential in the power Systems operation, historically this services haven’t been regulated in any way in Honduras. There have been changes recently into the regulatory framework in the entire electricity sector alongside the large-scale injection of photovoltaic and wind powered centrals in the System. Considering these scenarios, the ancillary services become a necessity in terms of the operation for the power system and the stability associated with it. In this paper, we analyze the technical and economic aspects related to the frequency control, voltage control and blackstart services, we compare the services provided in different countries and how it is possible to adapt the successful cases to the Honduran power system.


Author(s):  
V. A. Khrustalev ◽  
M. V. Garievskii ◽  
I. A. Rostuntsova ◽  
A. V. Portyankin

The purpose of the article is to study the possibility and feasibility of participation of nuclear power plants (NPPs) with VVER in emergency frequency control in power systems with a high proportion of nuclear power units and, at the same time, of reducing the power consumption for the own needs of the main circulation pumps during modes with power below nominal. To solve these problems, it was proposed to increase the achievable speeds of power gain (load increase) due to the installation of frequency controlled drives of the MCP. Large system frequency variations (caused by large imbalances between generation and demand) may jeopardize electrical equipment, in terms of maintaining stable and reliable operating conditions. For NPPs, the task of preventing or localizing accidents is even more important than for TPPs, since in case of major system accidents, it is possible to completely stop external power supply of the NPPs own needs. Thus, besides the requirements for the primary control of the frequency of NPPs with VVER, today we need more stringent requirements for their emergency acceleration and mobility. The operation of NPPs with long-term non-recoverable active power shortage causes a decrease in the speed of the main circulation pumps of NPPs with VVER and a decrease in the coolant flow rate. It is shown that the installation of variable frequency drives of the MCPs at NPP with VVER is appropriate not only to save energy consumption for their drive in partial modes, but also to increase the power of NPP above the nominal (without reducing the reserve before the heat exchange crisis in the reactor core) for the elimination of system accidents, and thus to improve the safety of the NPPs included in the power system.


Author(s):  
Dipayan Guha ◽  
Provas Kumar Roy ◽  
Subrata Banerjee

This chapter presents four effective evolutionary methods, namely grey wolf optimization (GWO), symbiotic organism search (SOS), JAYA, and teaching-learning-based optimization (TLBO), for solving automatic generation control (AGC) problem in power system. To show the effectiveness, two widely used interconnected power plants are examined. To extract maximum possible generation, distinct PID-controllers are designed employing ITAE-based fitness function. Further, to enhance the dynamic stability of concerned power systems, 2DOF-PID controllers are proposed in LFC area and optimally designed using aforesaid algorithms. To demonstrate the supremacy, obtained results are compared with some existing control algorithms. Moreover, robustness of the designed controller is believed under the action of random load perturbation (RLP). Finally, sensitivity analysis is carried out to show the stability of the designed system under loading and parametric disturbance conditions.


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