scholarly journals Impact of communication time delays on combined LFC and AVR of a multi-area hybrid system with IPFC-RFBs coordinated control strategy

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
C H. Naga Sai Kalyan ◽  
G. Sambasiva Rao
Keyword(s):  
Time Delays ◽  
Power Flow ◽  
Frequency Control ◽  
Dynamic Performance ◽  
Coordinated Control ◽  
Voltage Regulation ◽  
Load Frequency Control ◽  
Superior Performance ◽  
Communication Time ◽  
The Impact

AbstractIn this paper, the impact of communication time delays (CTDs) on combined load frequency control (LFC) and automatic voltage regulation (AVR) of a multi-area system with hybrid generation units is addressed. Investigation reveals that CTDs have significant effect on system performance. A classical PID controller is employed as a secondary regulator and its parametric gains are optimized with a differential evolution - artificial electric field algorithm (DE-AEFA). The superior performance of the presented algorithm is established by comparing with various optimization algorithms reported in the literature. The investigation is further extended to integration of redox flow batteries (RFBs) and interline power flow controller (IPFC) with tie-lines. Analysis reveals that IPFC and RFBs coordinated control enhances system dynamic performance. Finally, the robustness of the proposed control methodology is validated by sensitivity analysis during wide variations of system parameters and load.

scholarly journals A Systematic Review of Key Challenges in Hybrid HVAC–HVDC Grids

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5451
Author(s):  
Umar Javed ◽  
Neelam Mughees ◽  
Muhammad Jawad ◽  
Omar Azeem ◽  
Ghulam Abbas ◽  
...  
Keyword(s):  
High Voltage ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Control Strategies ◽  
Frequency Control ◽  
Voltage Regulation ◽  
Load Frequency Control ◽  
Future Research ◽  
Stable Operation ◽  
Dc Voltage

The concept of hybrid high-voltage alternating current (HVAC) and high-voltage direct current (HVDC) grid systems brings a massive advantage to reduce AC line loading, increased utilization of network infrastructure, and lower operational costs. However, it comes with issues, such as integration challenges, control strategies, optimization control, and security. The combined objectives in hybrid HVAC–HVDC grids are to achieve the fast regulation of DC voltage and frequency, optimal power flow, and stable operation during normal and abnormal conditions. The rise in hybrid HVAC–HVDC grids and associated issues are reviewed in this study along with state-of-the-art literature and developments that focus on modeling robust droop control, load frequency control, and DC voltage regulation techniques. The definitions, characteristics, and classifications of key issues are introduced. The paper summaries the key insights of hybrid HVAC–HVDC grids, current developments, and future research directions and prospects, which have led to the evolution of this field. Therefore, the motivation, novelty, and the main contribution of the survey is to comprehensively analyze the integration challenges, implemented control algorithms, employed optimization algorithms, and major security challenges of hybrid HVAC–HVDC systems. Moreover, future research prospects are identified, such as security algorithms’ constraints, dynamic contingency modeling, and cost-effective and reliable operation.

scholarly journals Water Cycle Algorithm Optimized Type II Fuzzy Controller for Load Frequency Control of a Multi-Area, Multi-Fuel System with Communication Time Delays

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5387
Author(s):  
Ch. Naga Sai Kalyan ◽  
B. Srikanth Goud ◽  
Ch. Rami Reddy ◽  
Haitham S. Ramadan ◽  
Mohit Bajaj ◽  
...  
Keyword(s):  
Power System ◽  
Time Delays ◽  
Power Flow ◽  
Water Cycle ◽  
Dynamical Behavior ◽  
Test System ◽  
Load Frequency Control ◽  
Type Ii ◽  
Water Cycle Algorithm ◽  
Communication Time

This paper puts forward the implementation of an intelligent type II fuzzy PID (T2-FPID) controller tweaked with a water cycle algorithm (WCA), subjected to an error multiplied with time area over integral (ITAE) objective index for regularizing the variations in frequency and interline power flow of an interconnected power system during load disturbances. The WCA-based T2-FPID is tested on a multi-area (MA) system comprising thermal-hydro-nuclear (THN) (MATHN) plants in each area. The dynamical behavior of the system is analyzed upon penetrating area 1 with a step load perturbation (SLP) of 10%. However, power system practicality constraints, such as generation rate constraints (GRCs) and time delays in communication (CTDs), are examined. Afterward, a territorial control scheme of a superconducting magnetic energy storage system (SMES) and a unified power flow controller (UPFC) is installed to further enhance the system performance. The dominancy of the presented WCA-tuned T2-FPID is revealed by testing it on a widely used dual-area hydro-thermal (DAHT) power system model named test system 1 in this paper. Analysis reveals the efficacy of the presented controller with other approaches reported in the recent literature. Finally, secondary and territorial regulation schemes are subjected to sensitivity analysis to deliberate the robustness.

Impact of electric vehicles aggregators with communication delays on stability delay margins of two-area load frequency control system

2021 ◽  
pp. 014233122110144
Author(s):  
Ausnain Naveed ◽  
Şahin Sönmez ◽  
Saffet Ayasun
Keyword(s):  
Time Delay ◽  
Electric Vehicles ◽  
Characteristic Equation ◽  
Frequency Control ◽  
Analytical Formula ◽  
Load Frequency Control ◽  
System Stability ◽  
Load Frequency ◽  
Communication Time ◽  
The Impact

This paper investigates the impact of electric vehicles (EVs) aggregator with communication time delay on stability delay margin of a two-area load frequency control (LFC) system. A frequency-domain exact method is used to calculate stability delay margins for various values of proportional-integral (PI) controller gains. The proposed method first eliminates the transcendental terms in the characteristic equation without using any approximation and then transforms the transcendental characteristic equation into a regular polynomial using a recursive approach. The key result of the elimination process is that real roots of the new polynomial correspond to imaginary roots of the transcendental characteristic equation. With the help of new polynomial, delay-dependent system stability and root tendency with respect to the time delay is determined. An analytical formula is then developed to compute delay margins in terms of system parameters. The qualitative impact of EVs aggregator on stability delay margins is thoroughly analysed and the results are verified by time domain simulations and quasi-polynomial mapping-based root finder (QPmR) algorithm.

scholarly journals Observer-Based Load Frequency Control for Island Microgrid with Photovoltaic Power

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Chaoxu Mu ◽  
Weiqiang Liu ◽  
Wei Xu ◽  
Md. Rabiul Islam
Keyword(s):  
Renewable Energy ◽  
Sliding Mode ◽  
Frequency Control ◽  
Load Frequency Control ◽  
Superior Performance ◽  
Load Frequency ◽  
Power Simulation ◽  
The Neural Network ◽  
Comparative Results ◽  
System Frequency

As renewable energy is widely integrated into the power system, the stochastic and intermittent power generation from renewable energy may cause system frequency deviating from the prescribed level, especially for a microgrid. In this paper, the load frequency control (LFC) of an island microgrid with photovoltaic (PV) power and electric vehicles (EVs) is investigated, where the EVs can be treated as distributed energy storages. Considering the disturbances from load change and PV power, an observer-based integral sliding mode (OISM) controller is designed to regulate the frequency back to the prescribed value, where the neural network observer is used to online estimate the PV power. Simulation studies on a benchmark microgrid system are presented to illustrate the effectiveness of OISM controller, and comparative results also demonstrate that the proposed method has a superior performance for stabilizing the frequency over the PID control.

scholarly journals Coordinated Control System between Grid–VSC and a DC Microgrid with Hybrid Energy Storage System

Electronics ◽  
2021 ◽  
Vol 10 (21) ◽  
pp. 2699
Author(s):  
Miguel Montilla-DJesus ◽  
Édinson Franco-Mejía ◽  
Edwin Rivas Trujillo ◽  
José Luis Rodriguez-Amenedo ◽  
Santiago Arnaltes
Keyword(s):  
Control Strategy ◽  
Power Flow ◽  
Storage System ◽  
Coordinated Control ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Electrical Network ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Dc Microgrid

Direct current microgrids (DCMGs) are currently presented as an alternative solution for small systems that feed sensitive electrical loads into DC. According to the scientific literature, DCMG maintains good voltage regulation. However, when the system is in islanded mode, very pronounced voltage variations are presented, compromising the system’s ability to achieve reliable and stable energy management. Therefore, the authors propose a solution, connecting the electrical network through a grid-tied voltage source converter (GVSC) in order to reduce voltage variations. A coordinated control strategy between the DCMG and GVSC is proposed to regulate the DC voltage and find a stable power flow between the various active elements, which feed the load. The results show that the control strategy between the GVSC and DCMG, when tested under different disturbances, improves the performance of the system, making it more reliable and stable. Furthermore, the GVSC supports the AC voltage at the point of common coupling (PCC) without reducing the operating capacity of the DCMG and without exceeding even its most restrictive limit. All simulations were carried out in MATLAB 2020.

scholarly journals Evaluation of the Simultaneous Operation of the Mechanisms for Cross-Border Interchange and Activation of the Regulating Reserves

2021 ◽  
Vol 11 (17) ◽  
pp. 8188
Author(s):  
Marcel Topler ◽  
Boštjan Polajžer
Keyword(s):  
Frequency Control ◽  
Primary Objective ◽  
Load Frequency Control ◽  
Simultaneous Operation ◽  
Dynamic Simulations ◽  
Cross Border ◽  
Power Variation ◽  
Balancing Energy ◽  
And Performance ◽  
The Impact

This article examines the mechanisms for cross-border interchange of the regulating reserves (RRs), i.e., the imbalance-netting process (INP) and the cross-border activation of the RRs (CBRR). Both mechanisms are an additional service of frequency restoration reserves in the power system and connect different control areas (CAs) via virtual tie-lines to release RRs and reduce balancing energy. The primary objective of the INP is to net the demand for RRs between the cooperating CAs with different signs of interchange power variation. In contrast, the primary objective of the CBRR is to activate the RRs in the cooperating CAs with matching signs of interchange power variation. In this way, the ancillary services market and the European balancing system should be improved. However, both the INP and CBRR include a frequency term and thus impact the frequency response of the cooperating CAs. Therefore, the impact of the simultaneous operation of the INP and CBRR on the load-frequency control (LFC) and performance is comprehensively evaluated with dynamic simulations of a three-CA testing system, which no previous studies investigated before. In addition, a function for correction power adjustment is proposed to prevent the undesirable simultaneous activation of the INP and CBRR. In this way, area control error (ACE) and scheduled control power are decreased since undesired correction is prevented. The dynamic simulations confirmed that the simultaneous operation of the INP and CBRR reduced the balancing energy and decreased the unintended exchange of energy. Consequently, the LFC and performance were improved in this way. However, the impact of the INP and CBRR on the frequency quality has no unambiguous conclusions.

scholarly journals PI and LQR controllers for Frequency Regulation including Wind Generation

2018 ◽  
Vol 8 (5) ◽  
pp. 3711 ◽  
Author(s):  
Semaria Ruiz ◽  
Julian Patiño ◽  
Jairo Espinosa
Keyword(s):  
Power Systems ◽  
Wind Turbines ◽  
Frequency Control ◽  
Test System ◽  
Performance Comparison ◽  
Load Frequency Control ◽  
Superior Performance ◽  
Frequency Regulation ◽  
Control Effort ◽  
Load Frequency

<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>

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