scholarly journals Fast Frequency Control Scheme through Adaptive Virtual Inertia Emulation

Author(s):  
Uros Markovic ◽  
Zhongda Chu ◽  
Petros Aristidou ◽  
Gabriela Hug
Author(s):  
Abdullahi Bala Kunya ◽  
Mehmet Argin ◽  
Yusuf Jibril ◽  
Yusuf Abubakar Shaaban

Abstract Background Automatic generation control (AGC) of multi-area interconnected power system (IPS) is often designed with negligible cross-coupling between the load frequency control (LFC) and automatic voltage regulation (AVR) loops. This is because the AVR loop is considerably faster than that of LFC. However, with the introduction of slow optimal control action on the AVR, positive damping effect can be achieved on the LFC loop thereby improving the frequency control. In this paper, LFC synchronized with AVR in three-area IPS is proposed. Model predictive controller (MPC) configured in a dense distributed pattern, due to its online set-point tacking is used as the supplementary controller. The dynamics of the IPS subjected to multi-area step and random load disturbances are studied. The efficacy of the developed scheme is ascertained by simulating the disturbed system in MATLAB/Simulink. Results Based on the comparative analysis on the system responses, it is established that by cross-coupling the LFC loop with AVR, reductions of 66.45% and 59.09% in the frequency and tie-line power maximum deviations respectively are observed, while the respective settling times are found to be reduced by 29.68% and 22.77% when compared with the uncoordinated control scheme. In addition, the standard deviation and variance of the integral time absolute error of the system’s responses have reduced by 23.21% and 20.83% respectively compared to those obtained in a similar study. Conclusions The reduction in the maximum deviations and settling times in the system states indicates that introducing the voltage control via AVR loop has improved the frequency control significantly. While the lower standard deviation and variance of the integral time absolute error signify improvement in the robustness of the developed algorithm. However, this improvement is at the detriment of the controller size and computational complexity. In the uncoordinated control scheme, the control vector is one-dimensional, while in the coordinated scheme, the control vector is two-dimensional for each CA.


2020 ◽  
Vol 5 (1) ◽  
pp. 2
Author(s):  
Hady H. Fayek

Remote farms in Africa are cultivated lands planned for 100% sustainable energy and organic agriculture in the future. This paper presents the load frequency control of a two-area power system feeding those farms. The power system is supplied by renewable technologies and storage facilities only which are photovoltaics, biogas, biodiesel, solar thermal, battery storage and flywheel storage systems. Each of those facilities has 150-kW capacity. This paper presents a model for each renewable energy technology and energy storage facility. The frequency is controlled by using a novel non-linear fractional order proportional integral derivative control scheme (NFOPID). The novel scheme is compared to a non-linear PID controller (NPID), fractional order PID controller (FOPID), and conventional PID. The effect of the different degradation factors related to the communication infrastructure, such as the time delay and packet loss, are modeled and simulated to assess the controlled system performance. A new cost function is presented in this research. The four controllers are tuned by novel poor and rich optimization (PRO) algorithm at different operating conditions. PRO controller design is compared to other state of the art techniques in this paper. The results show that the PRO design for a novel NFOPID controller has a promising future in load frequency control considering communication delays and packet loss. The simulation and optimization are applied on MATLAB/SIMULINK 2017a environment.


Author(s):  
Anjana Jain ◽  
R. Saravanakumar ◽  
S. Shankar ◽  
V. Vanitha

Abstract The variable-speed Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion System (WECS) attracts the maximum power from wind, but voltage-regulation and frequency-control of the system in standalone operation is a challenging task A modern-control-based-tracking of power from wind for its best utilization is proposed in this paper for standalone PMSG based hybrid-WECS comprising Battery Energy Storage System (BESS). An Adaptive Synchronous Reference Frame Phase-Locked-Loop (SRF-PLL) based control scheme for load side bi-directional voltage source converter (VSC) is presented for the system. MATLAB/Simulink model is developed for simulation study for the proposed system and the effectiveness of the controller for bi-directional-converter is discussed under different operating conditions: like variable wind-velocity, sudden load variation, and load unbalancing. Converter control scheme enhances the power smoothening, supply-load power-matching. Also it is able to regulate the active & reactive power from PMSG-BESS hybrid system with control of fluctuations in voltage & frequency with respect to varying operating conditions. Proposed controller successfully offers reactive-power-compensation, harmonics-reduction, and power-balancing. The proposed scheme is based on proportional & integral (PI) controller. Also system is experimentally validated in the laboratory-environment and results are presented here.


2019 ◽  
Vol 9 (15) ◽  
pp. 3052
Author(s):  
Jiafu Yin ◽  
Dongmei Zhao

Due to the potential of thermal storage being similar to that of the conventional battery, air conditioning (AC) has gained great popularity for its potential to provide ancillary services and emergency reserves. In order to integrate numerous inverter ACs into secondary frequency control, a hierarchical distributed control framework which incorporates a virtual battery model of inverter AC is developed. A comprehensive derivation of a second-order virtual battery model has been strictly posed to formulate the frequency response characteristics of inverter AC. In the hierarchical control scheme, a modified control performance index is utilized to evaluate the available capacity of traditional regulation generators. A coordinated frequency control strategy is derived to exploit the complementary and advantageous characteristics of regulation generators and aggregated AC. A distributed consensus control strategy is developed to guarantee the fair participation of heterogeneous AC in frequency regulation. The finite-time consensus protocol is introduced to ensure the fast convergence of power tracking and the state-of-charge (SOC) consistency of numerous ACs. The effectiveness of the proposed control strategy is validated by a variety of illustrative examples.


2015 ◽  
Vol 9 (15) ◽  
pp. 2303-2310 ◽  
Author(s):  
Yu-Qing Bao ◽  
Yang Li ◽  
Beibei Wang ◽  
Ying-Yi Hong

Author(s):  
Chi-Wei Kuo ◽  
C. Steve Suh

A novel time-frequency nonlinear scheme demonstrated to be feasible for the control of dynamic instability including bifurcation, non-autonomous time-delay feedback oscillators, and route-to-chaos in many nonlinear systems is applied to the control of a time-delayed system. The control scheme features wavelet adaptive filters for simultaneous time-frequency resolution. Specifically Discrete Wavelet transform (DWT) is used to address the nonstationary nature of a chaotic system. The concept of active noise control is also adopted. The scheme applied the filter-x least mean square (FXLMS) algorithm which promotes convergence speed and increases performance. In the time-frequency control scheme, the FXLMS algorithm is modified by adding an adaptive filter to identify the system in real-time in order to construct a wavelet-based time-frequency controller capable of parallel on-line modeling. The scheme of such a construct, which possesses joint time-frequency resolution and embodies on-line FXLMS, is able to control non-autonomous, nonstationary system responses. Although the controller design is shown to successfully moderate the dynamic instability of the time-delay feedback oscillator and unconditionally warrant a limit cycle, parameters are required to be optimized. In this paper, the setting of the control parameters such as control time step, sampling rate, wavelet filter vector, and step size are studied and optimized to control a time-delay feedback oscillators of a nonautonomous type. The time-delayed oscillators have been applied in a broad set of fields including sensor design, manufacturing, and machine dynamics, but they can be easily perturbed to exhibit complex dynamical responses even with a small perturbation from the time-delay feedback. These responses for the system have a very negative impact on the stability, and thus output quality. Through employingfrequency-time control technique, the time responses of the time-delay feedback system to external disturbances are properly mitigated and the frequency responses are also suppressed, thus rendering the controlled responses quasi-periodic.


2020 ◽  
Vol 15 ◽  

Load frequency control (LFC) for multi-area restructured power system using discrete controlscheme has been suggested in this paper. The proposed LFC scheme utilizes synchronously measured dataof frequency and tie-line power to calculate area control error (ACE). A discrete non-integer proportionalintegral derivative controller (D-FOPID) has been used to derive frequency error to zero. Two-area thermaland four-area hydro thermal deregulated power system has been used to investigate various LFC issues. Theoptimal factors of D-FOPID have been obtained using big bang big crunch (BBBC) algorithm. The systemresults under MATLAB/Simulink validate that D-FOPID effectively work under different types of contractscenarios. D-FOPID performance has also been compared to discrete proportional integral derivativecontroller (D-PID). Further the compliance with control standards of North American electric reliabilitycouncil (NERC) has also been ensured for both the controller.


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