scholarly journals Provision of Frequency Stability of an Islanded Microgrid Using a Novel Virtual Inertia Control and a Fractional Order Cascade Controller

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4152
Author(s):  
Soroush Oshnoei ◽  
Mohammadreza Aghamohammadi ◽  
Siavash Oshnoei ◽  
Arman Oshnoei ◽  
Behnam Mohammadi-Ivatloo
Keyword(s):  
Fractional Order ◽  
Degrees Of Freedom ◽  
Search Algorithm ◽  
Frequency Control ◽  
Renewable Energy Sources ◽  
Dynamic Performance ◽  
Frequency Stability ◽  
Virtual Inertia ◽  
Inertia Control ◽  
System Frequency

Nowadays, the renewable energy sources in microgrids (MGs) have high participation to supply the consumer’s demand. In such MGs, the problems such as the system frequency stability, inertia, and damping reduction are threatened. To overcome this challenge, employing the virtual inertia control (VIC) concept in the MG structure could be considered as a viable solution to improve the system frequency response. Hence, this work proposes a novel modeling for VIC in an islanded MG that provides simultaneous emulation of the primary frequency control, virtual inertia, and damping. To show the efficiency of the proposed technique, a comparison is made between the dynamic performance of the proposed VIC and conventional VIC under different scenarios. The results indicate that the proposed VIC presents superior frequency performance in comparison with conventional VIC. In addition to VIC modeling, a new cascade controller based on three-degrees of freedom and fractional-order controllers (FOCs) is proposed as an MG secondary controller. The effectiveness of the proposed controller is compared to tilt-integral-derivative and FO proportional-integral-derivative controllers. The Squirrel search algorithm is utilized to obtain the optimal coefficients of the controllers. The results demonstrate that the proposed controller improves the MG frequency performance over other controllers. Eventually, the sensitivity analysis is performed to investigate the robustness of the proposed controller in the face of the variations of the parameters.

scholarly journals Dynamic Frequency Support from a DFIG-Based Wind Turbine Generator via Virtual Inertia Control

2020 ◽  
Vol 10 (10) ◽  
pp. 3376 ◽  
Author(s):  
Dejian Yang ◽  
Enshu Jin ◽  
Jiahan You ◽  
Liang Hua
Keyword(s):  
Wind Speed ◽  
Power Systems ◽  
Wind Turbine ◽  
Control Strategy ◽  
Control Method ◽  
Frequency Stability ◽  
Virtual Inertia ◽  
Inertia Control ◽  
System Frequency ◽  
Inertia Response

As the penetrated level of wind in power grids increases, the online system inertia becomes weak. Doubly-fed induction generator (DFIG)-based wind turbine generators (WTGs) are required to provide virtual inertia response to support system frequency. The present inertia control strategy with fixed control gain is not suitable and may cause stall of the DFIG-based WTG, as the virtual inertia response potential from the DFIG-based WTG is different with various wind speed conditions. This paper addresses a virtual inertia control method for the DFIG-based WTGs to improve the system frequency stability without causing stalling of the wind turbine for various wind speed conditions. The effectiveness of the proposed virtual inertia control method is investigated in a small system embedded with the DFIG-based WTG. Results demonstrate that the proposed virtual inertia strategy improves the frequency stability without causing the rotor speed security issue. Thus, the proposed control strategy can secure the dynamic system frequency security of power systems under the scenarios of full and partial loads, and, consequently, the proposed method provides a promising solution of ancillary services to power systems.

Enhancement the Dynamic Performance of Islanded Microgrid Using a Coordination of Frequency Control and Digital Protection

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Emad A. Mohamed ◽  
Yasunori Mitani
Keyword(s):  
Dynamic Stability ◽  
Frequency Control ◽  
Dynamic Performance ◽  
Load Frequency Control ◽  
Renewable Energy Resources ◽  
Promising Solution ◽  
Islanded Microgrid ◽  
Virtual Inertia ◽  
Inertia Control ◽  
Digital Protection

Abstract This paper presents an assortment study between the virtual inertia control (VIC)-based a new optimal PID controller, load frequency control (LFC), and the digital protection for an islanded microgrid (MG) taking into consideration the emerging level of renewable energy resources (RERs), which is a promising solution. However, the reduction in system inertia due to increasing the amount of RERs causes undesirable impact to MG dynamic stability, threatens the system security, and could lead to complete blackouts as well as damages to the system equipment. Therefore, maintaining the dynamic security in MGs is one of the important challenges, which considered in this paper using a specific design of a digital over/under frequency relay (OUFR) with coordination of the VIC to protect the MG against high-frequency variations. To prove the effectiveness of the proposed coordination strategy, it has been tested considering sudden load change, high integration of RERs. Moreover, the sensitivity analysis of the presented technique was examined by varying the inertia level of MG system. The results stated that the proposed coordination can effectively regulate the MG frequency and maintain the dynamic stability and security.

scholarly journals Applying Virtual Inertia Control Topology to SMES System for Frequency Stability Improvement of Low-Inertia Microgrids Driven by High Renewables

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3902 ◽  
Author(s):  
Thongchart Kerdphol ◽  
Masayuki Watanabe ◽  
Yasunori Mitani ◽  
Veena Phunpeng
Keyword(s):  
Control System ◽  
Control Method ◽  
Magnetic Energy ◽  
Frequency Stability ◽  
Property A ◽  
Virtual Inertia ◽  
Inertia Control ◽  
And Control ◽  
System Frequency ◽  
Control Topology

To integrate renewable energy into microgrids with a favorable inertia property, a virtual inertia control application is needed. Considering the inertia emulation capabilities, insufficient emulation of inertia power due to the lower and short-term power of storage systems could significantly cause system instability and failure. To enhance such capability, this paper applies a virtual inertia control topology to the superconducting magnetic energy storage (SMES) technology. The SMES-based virtual inertia control system is implemented in a microgrid with renewables to emulate sufficient inertia power and maintain good system frequency stability. The efficacy and control performance of the proposed control method are compared with those of the traditional virtual inertia control system. Simulation results show that the shortage of system inertia due to renewable penetration is properly compensated by the proposed control method, improving system frequency stability and maintaining the robustness of system operations.

DFIG Virtual Inertia Frequency Control Strategy

2013 ◽  
Vol 680 ◽  
pp. 505-508
Author(s):  
Huan Wang ◽  
Lei Pan
Keyword(s):  
Tracking Control ◽  
Frequency Control ◽  
Control Process ◽  
Active Power ◽  
Virtual Inertia ◽  
Inertia Control ◽  
Turbine Speed ◽  
Rotor Side Converter ◽  
System Frequency ◽  
Dynamic Frequency

During the DFIG maximum power tracking control process, the rotor side converter is only based on the wind turbine speed to regulate the active power output; it almost no provides effective inertia. DFIG could add auxiliary virtual inertia control system, when the system frequency is reduced, releasing the rotor "hidden" kinetic energy to support the grid dynamic frequency.

Višestepena brza regulacija frekvencije u elektroenergetskim sistemima sa neravnomernom distribucijom inercije

2021 ◽  
Vol XXIII (4) ◽  
pp. 1-7
Author(s):  
Jelena Stojković ◽  
◽  
Predrag Stefanov
Keyword(s):  
Control Strategy ◽  
Frequency Control ◽  
Renewable Energy Sources ◽  
Frequency Stability ◽  
Test System ◽  
Rate Of Change ◽  
Electricity Production ◽  
Rotational Inertia ◽  
Telecommunications Infrastructure ◽  
Local Measurements

Integration of renewable energy sources (RES) is one of the key factors in the fight against climate change and they are becoming to take a larger share in electricity production. The systems with a high penetration of RES have small rotational inertia and are more vulnerable in terms of frequency stability. This paper proposes strategy for multistage fast frequency control (FFC) provided by converter-connected resources. They can quickly change the output active power and provide frequency support immediately after the disturbance during the period before that frequency reaches its nadir. The proposed control strategy uses only local measurements of the rate of change of frequency (RoCoF) and there is no need for complex telecommunications infrastructure. The multistage approach enables dispatched reserve to be proportional to the size of disturbance. RoCoF based FFC provides that more reserves would be dispatched in low-inertia areas that are more sensitive to disturbance and therefore enhance frequency stability. The proposed control strategy is validated on a test system of 3 coherent areas and the simulation results confirm that more reserve is dispatched in low-inertia areas that are more affected by disturbance.

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