Flexible AC Transmission System Controllers Research Articles

Multi-Objective Optimization in the Presence of OGIPFC Using NSMMP Algorithm

Background: Customers expect quality, uninterrupted power with cost-effective electricity in the latest trend. However, outages, severe storms, old infrastructure, and cost pressures can lead to ambiguity in power generation and transmission. To improve line power transmission capability, the right flexible AC transmission systems (FACTS) device may save millions of dollars. Methods: In this study, a FACTS controller named Optimal Generalized Interline Power Flow Controller (OGIPFC) was developed. Furthermore, for optimization, the Modified Marine Predator Algorithm (MMPA), which is a modification of the recently developed Marine Predator Algorithm (MPA). The optimum technique was used to evaluate a set of prioritized considered objective minimizations. A variety of factors must be maximized, such as generation cost, emissions, and power loss. Results: The performance of the proposed algorithm was analysed on benchmark test functions, and then single objective optimization problems of standard IEEE-30 bus system were solved and compared with the existing algorithms. The proposed algorithm was restricted to solving the single objective problem only, so it was further implemented with non-dominating sorting to solve the multiobjective optimization problem. The proposed multi-objective version is named as Non-dominating Sorting Modified Marine Predator Algorithm (NSMMPA), and it was validated on benchmark test functions and the IEEE-30 bus system. Conclusion: Finally, the OPF problem was solved with the incorporation of OGIPFC using the proposed methods, which resulted in better solutions and made the system more effective in operation.

Improving Interarea Mode Oscillation Damping in Multi-Machine Energy Systems through a Coordinated PSS and FACTS Controller Framework

Power system stability is of paramount importance in the context of energy sustainability. The reliable and efficient operation of power systems is crucial for supporting modern societies, economies, and the growing demand for electricity while minimizing environmental impact and increasing sustainability. Due to the insufficient effect of power system stabilizers (PSSs) on damping the inter-area mode oscillations, Flexible AC Transmission System (FACTS) devices are utilized for damping this mode and stabilizing power systems. In the present study, a novel optimization framework considering different and variable weight coefficients based on eigenvalue locations is presented, and the parameters of PSS and variable impedance devices, including static Volt-Ampere Reactive (VAR) compensator (SVC) and Thyristor-Controlled Series Compensator (TCSC) (comprising amplifying gain factor and time constants of phase-compensating blocks), are optimized in a coordinated manner using the proposed optimization framework built based on genetic algorithm (GA). Moreover, in the suggested optimization framework, the locations of FACTS devices and control signals are considered optimization parameters. Numerical results for the IEEE 69-bus power system demonstrated an effective improvement in the damping of inter-area modes utilizing the offered approach.

Performance Evaluation of Optimally Placed SVC for Dynamic Stability of the Power System

Given the complexity of power systems, particularly in the deregulated power industry found in Nigeria, a consistent, safe, controllable, and high-quality power supply is required. The loss of the system's overall damping torque, which reduces the system's susceptibility to fluctuations and problems with dynamic stability, is one of the key downsides of network expansion. Flexible AC transmission systems (FACTS) controllers have been used to overcome problems with power system stability control. In order to improve dynamic stability, this study investigates how the generator's rotor angle, speed, voltage magnitude profile, and real power affect how well SVC operates under the effect of a three-phase fault. With a fault introduced on Bus 33 (Geregu Substation) and SVC placed optimally on Bus 21 (Jos Transmission Station) using voltage stability sensitivity factor (VSSF) after the simulation of continuation power flow (CPF), the 48-bus power system network in Nigeria was modeled using commercial PSAT software in a MATLAB environment. The power system's oscillation was significantly reduced, and the voltage profile was enhanced for power system dynamic stability, per simulation results with and without SVC.

Enhancement of Power Systems Transient Stability with TCSC: A Case study of The Nigerian 330 kV, 48-Bus Network

A steady, safe, controllable, and high-quality power supply is necessary given the complexity of power systems, especially in the deregulated power sector seen in Nigeria. One of the main drawbacks of network expansion is the loss of the system's overall damping torque, which mitigates the system resulting to fluctuations and transient instability. Power system stability control difficulties have been addressed using flexible AC transmission systems (FACTS) controllers. This study examines the responses of the generator rotor angle, speed, Q-axis and D-axis voltage components behind transient reactance as well as the voltage magnitude profile under the influence of a three-phase fault for the purpose of enhancing transient stability. The Nigerian 48-bus power system network was modeled using commercial PSAT software in a MATLAB environment with a fault induced on Bus 33 (Geregu SubStation) and TCSC optimally positioned on line 21-28 using continuation power flow (CPF). According to simulation results with and without TCSC, a significant amount of oscillation in the power system was dampened, and the voltage profile was improved for power system transient stability.

A preordainment approach for design of auxiliary damping controller and SSSC tuning to enhance SSR mode stability in DFIG based windfarm

ABSTRACT Sub-synchronous resonance (SSR) is a growing concern in wind turbine generators-based series capacitive compensated networks at low wind speed and peak compensation levels. It is feasible to increase the stability of SSR mode caused by a transmission line’s passive series compensation by providing active compensation using a flexible ac transmission system controller cooperating with an auxiliary damping controller. This paper presents preordainment and enhancement of SSR mode in DFIG-based series capacitive compensated line by incorporating an additional damping controller into the static synchronous series compensator (SSSC). The auxiliary damping controller modulates the reactive voltage injected by SSSC into the transmission line by considering the appropriate input control signal, reflecting the SSR instability, and giving the maximum damping to the SSR mode. The optimal input control signal is determined via residue analysis, and the design procedure of the auxiliary damping controller is presented using root locus plots. The root locus plots offer a visual representation of the loci for each mode and preordain eigenvalues for new stability, which aids in the design of the auxiliary damping controller. This feature allows to predetermine the SSR mode eigenvalue while before connecting it with SSSC. Accordingly, it provides a controlled dampening to SSR mode such that the desired damping ratio for SSR mode can be achieved without influencing the stability of other modes. The impact of the designed auxiliary damping controller is examined at high compensation levels and low wind speed. The eigenvalue analysis results show that the preordained eigenvalues found using root locus plots are correct and the proposed approach predominantly enhances the stability of SSR mode. The fast Fourier transform (FFT) analysis and transient simulations are used to show the detuning and dampening of SSR mode. The proposed work is executed using MATLAB/Simulink.

The use of numerical method in an electric grid coupled to a wind farm to compare different kinds of flexible AC transmission systems

The PSAT software was used in this study to analyse and compare the performance of hybrid compensators such as SSSC-STATCOM (controllers), TCSC-SVC (compensators), and UPFC in an electric grid coupled to a wind farm. The flexible AC transmission system (FACTS) technology is used to provide a continual power flow and to provide new ways to control the electric system network. In the FACTS devices, the UPFC (Unified Power Flow Controller) is one of the most adaptable, flexible, and complicated power electric devices. The active and reactive power flows and the local voltage on the bus can be regulated by UPFC; it can also resolve the problem of harmonics. The TCSC (Thyristor-Controlled Series Capacitor) consists as a series-compensating capacitor shunted by a thyristor-controlled reactor. The SVC (Static Var Compensator) is the first shunt generation FACTS controller. We can observe that the UPFC controller has an effective power flow control, shorter setting time and a shorter overshoot. The UPFC obtained a well-known reputation for high controllability in power systems. The multilevel Unified Power Flow Controller can be operated in Static Synchronous Compensator (STATCOM), in Static Synchronous Series Compensator SSSC and exactly in the UPFC compensator. The results of this research compare the hybrid controllers and investigate the effects of TCSC-SVC, SSSC-STATCOM, and UPFC on voltage, phase angle stability, and the active and reactive power in the tested system. The purpose of this comparison is to improve dynamic voltage regulation, especially when the utilisation of nonlinear loads and the presence of fault and breaker rise. These hybrid controllers have been shown to outperform series or shunt compensators; however, when compared to hybrid compensators SSSC-STATCOM, TCSC-SVC, and UPFC, the results employing the numerical method in the UPFC are more significant. The UPFC is the best hybrid controller in this study, and the compensators SSSC-STATCOM outperform the controllers TCSC-SVC.

Analysis and Comparison of Performance of Interline Power Flow Controller with Various Control Algorithms under Various Power Stability Problems

The Interline Power Flow Controller (IPFC) is a voltage source converter based Flexible AC Transmission System (FACTS) controller for series compensation and power flow management among a substation's multiline transmission systems. Individual Voltage Source Converters (VSC) can inject reactive voltage that can be adjusted to manage active power flow in a line. This VSC is used to convert DC voltage to AC voltage and the voltage is kept constant in the entire process. In this article, a circuit model for IPFC is constructed, and a simulation of an interline power flow controller is performed, with control performed utilizing a variety of algorithms, including adaptive weighted feedback, gravitational search, BAT, and ANT colony optimization. The system's performance was evaluated in a variety of scenarios, including fault incidence, synchronous load connection, and asynchronous load connection. The design of system and analysis of system has been carried out using MATLAB Simulink in terms of various parameters at point of common coupling like voltage, current, power and power factor.

Congestion Management in Power Transmission Lines with Advanced Control Using Innovative Algorithm

It can be challenging to allocate all the necessary power to a supply in a modern power system if the power lines are overloaded. The conventional power system, monitored by flexible AC transmission system (FACTS) controllers, is one answer to this issue because it can increase the electrical power system's ability to deal with rapid variations in working circumstances. The advanced interline power flow controller using a constriction factor-based particle swarm optimization (CFBPSO) algorithm (AIPFC) was proposed in this paper as an optimal power flow control for controlling congestion in transmission lines. When comparing the performance of single-line and multi-line FACTS controllers, the latter is shown to be more effective overall. This paper presents a comprehensive model of an advanced interline power flow controller (AIPFC) and explores the effect of situating the controller in the most advantageous physical location. To address OPF concerns when using state-of-the-art IPFC, a novel algorithm, CFBPSO, is proposed. A traditional IEEE 30 bus test system is used to verify the proposed method. A standard IEEE 30 bus test system is used to verify the accuracy of the proposed method. In their paper, the researchers show that their proposed algorithm works by showing that the value of the objective function goes down.

Power system transient stability improvement with FACTS controllers using SSSC-based controller

Early power systems were rudimentary and local in nature. Power consumption has risen quickly in recent years, resulting in more complicated systems. However, expansion of transmission and generating is limited due to limited resource availability and tight environmental regulations. As a result, today's power systems are increasingly loaded and running under stress, putting them close to their transient stability limits. The study discussed in this paper focuses on employing contemporary PSS to improve power system reliability. The work presented in this thesis mainly focuses on power system stability improvement using modern PSS. In modern power systems trend of using wide area damping controllers and wide area signals are increasing. Also Flexible AC Transmission Systems (FACTS) based controllers are most suitable for stability enhancement and power control. This method proposed tie line power as a broad area control signal for the Static Synchronous Series Compensator (SSSC) based controller based on the geometric measure of joint index value. Kundur's two-area, four-machine system is controlled by this controller. For this system, the effectiveness of the selected signal is applied to an SSSC-based controller. The results reveal that the picked signal performs better than the non-selected signal (rotor speed deviation).

Multi-attribute decision making approach for placement of dynaflow controllers in a power system network using particle mobility honey bee algorithm

The appropriate placement of flexible AC transmission systems (FACTS) is becoming more critical in power systems. FACTS controllers that are not correctly positioned cannot provide optimum performance and harm the system. The “dynaflow device,“ newly developed FACTS controller, must be inspected to verify that it is correctly placed on the power network before being used. Multi-attribute decision-making techniques (MADMs) address a broad range of decision-making problems, which are frequently employed in energy planning. In this work, a MADM combined with a particle mobility honey bee algorithm (PMHBA) is proposed to determine the optimum places for the simultaneous installation of two dynaflow devices to maximise efficiency. The method is shown with the help of an IEEE 30 bus power system network. Two main MADM methods, namely, the weighted sum model (WSM) and the technique for order preference by similarity to ideal solution (TOPSIS), were examined with respect to the ranks of alternatives.

A mathematical framework of ANFIS tuned UPQC controlled RES based isolated microgrid system

This paper presented a nascent mathematical modeling of ANFIS tuned Unified Power Quality Conditioner (UPQC) controlled hybrid microgrid incoprating an Induction generator (IG) for a wind energy- system and an alternator for conventional generation. The mathematical frame of the hybrid microgrid system is presented using power equalities. A powerful Flexible AC Transmission system (FACTS) controller UPQC, generally used with conventional sources is considered to control the voltage and reactive power flow in the presented microgrid framework. Further Adaptive Neuro-Fuzzy Inference System (ANFIS) technique has been used to optimize the FACTS controller UPQC in MATLAB software.

Sizing and Sitting of Static VAR Compensator (SVC) Using Hybrid Optimization of Combined Cuckoo Search (CS) and Antlion Optimization (ALO) Algorithms

Worldwide, due to the abrupt growth of population, the load demand has been rising dramatically in the last few years. This led to an increase in branch overloads, voltage deviations, and power losses. These problems may result in line outages or the occurrence of blackouts. Flexible AC transmission system (FACTS) devices can be installed in the power system to ensure increased power flow capability and flexible voltage control to address these issues. In this paper, one of the most used FACTS is utilised. It is called Static VAR Compensator (SVC). This controller is one of the most commonly used shunt FACTS controllers due to its low cost in comparison to others, ease of operation, and integration into the power grid. Two Optimization algorithms are combined to form a hybrid optimization approach: Cuckoo Search (CS) and Antlion Optimization (ALO). This hybrid approach employs the exploration of ALO to adjust the optimum allocation and size for SVCs in the power system. This study proposes the IEEE 57 bus scheme as a fairly large structure, with the 50 and 41 branch outages considered the worst-case scenarios for line outages in this system. The simulation results show that the proposed methodology balances exploring the research space and exploiting the best existing solutions compared to some of the other introduced approaches in the literature.

Optimization of Voltage Security with Placement of FACTS Device Using Modified Newton–Raphson Approach: A Case Study of Nigerian Transmission Network

Power flow reliability, voltage security and transmission congestion management are paramount operational issues in a power system. Flexible AC transmission system (FACTS) controllers are suitable technologies that can provide compensation and dynamic control of power system transmission parameters to enhance effective performance and reliability. The interline power flow controller (IPFC), if optimally placed, can regulate the impedance of multiple lines to improve active power transfer capacity and voltage profile. This study examines the performance of IPFCs for voltage enhancement by suppressing fluctuation. A modified Newton–Raphson load flow problem with an incorporated IPFC variable has been formulated with the objective to improve voltage stability and maintain active power flow. The effectiveness of the proposed method was tested on the Nigerian 41 bus transmission network. The obtained result of the system with an IPFC placed at the weakest bus of the network was compared with Newton–Raphson load flow analysis of the same network without an IPFC. The results of load flow analysis for Case 1 (the system without an IPFC) showed that the transmission network without an IPFC had a real power loss of 4.699488 p.u., and reactive power loss of 4.467413 p.u., whereas the integration of an IPFC to the power flow formation in Case 2 resulted in the reduction in the transmission network’s overall losses to 0.55297 p.u. and −38.3329 p.u. The modified method proves effective as the power system network with an IPFC returns a more stable voltage profile and improves active power flow. In addition, this method, similar to all other mathematical optimization approaches, returns a strong accurate result but may be a drawback in terms of longer computational time compared with metaheuristic methods which are preferred for a larger network system.

Performance enhancement of renewable based deregulated system using distributed power flow controller, Redox flow battery, and Tesla power wall battery

ABSTRACT In the upcoming era, when conventional sources will mostly be replaced by renewable energy sources, engineers may face huge problem during controller design. For this large interconnected hybrid automatic generation control (AGC) system, high proficient and intelligent control techniques are needed. Hence, a newly developed fractional order tilt integral derivative double integral filter plus (FOTIDF-II) controller has been proposed in this research work. To overcome slow convergence feature of moth swarm algorithm (MSA), chaotic-based moth swarm algorithm (CMSA) is introduced by incorporating chaos into the MSA algorithm. Afterward, to upgrade the performance of AGC, the newly proposed controller is incorporated to the said system. The gains and fractional order parameters such as order of integrator, differentiator and filter coefficients of the proposed controller are optimized using CMSA optimizing technique. It is observed that the dynamic performance of the proposed CMSA optimized FOTIDF-II controller is better than the CMSA optimized PID. Furthermore, the performance of CMSA in the presence of different flexible AC transmission system (FACTs) and storage devices such as distributed power flow controller (DPFC), redox flow battery (RFB), and Tesla power wall (TPWA) battery (i.e Storage devices) along with proposed controller is compared with MSA-based PID controller with same combination of FACTs controller. Afterwards, superiority of the proposed controller has been judged in three area renewable-based AGC system under realistic environment.

Smart Wires and Modular FACTS Controllers for Smart Grid Applications: A Review

Flexible AC Transmission System (FACTS) controller has got unanimous acceptance in the electric power industry due to their power control capability especially in transmission and sub transmission networks. These FACTS devices play a decisive role in stability enhancement and effective asset utilization. The controllers suffer from grave drawbacks such as colossal size, poor reliability, high cost, and unavailability of experienced personnel for operation and maintenance, which makes them unapt to be used in smart grid and modern power system applications. These inadequacies are effectively assuaged by the distributed FACTS devices, which are proliferated along the transmission lines, are said to be portable, cost-effective, highly reliable, and easy to maintain. This paper explores an exhaustive review of the smart wires and modular FACTS controllers with their application in smart power networks.

Smart Wires and Modular FACTS Controllers for Smart Grid Applications: A Review

Flexible AC Transmission System (FACTS) controller has got unanimous acceptance in the electric power industry due to their power control capability especially in transmission and sub transmission networks. These FACTS devices play a decisive role in stability enhancement and effective asset utilization. The controllers suffer from grave drawbacks such as colossal size, poor reliability, high cost, and unavailability of experienced personnel for operation and maintenance, which makes them unapt to be used in smart grid and modern power system applications. These inadequacies are effectively assuaged by the distributed FACTS devices, which are proliferated along the transmission lines, are said to be portable, cost-effective, highly reliable, and easy to maintain. This paper explores an exhaustive review of the smart wires and modular FACTS controllers with their application in smart power networks.

Management of a Solar-PV System with Energy Storage

A solar-PV system is generally connected to distributed generation (DG) by the utility grid. The solar inverter retains some capacity after active power generation. Reactive power compensation can be achieved by utilizing the remaining capacity of the solar-PV inverter. This paper introduces an energy management system (EMS) for real and reactive power management. The proposed EMS includes two modes: PV-STATCOM and islanding. In PV-STATCOM mode, the PI control is used whereas for the islanding mode, voltage frequency control is employed. This paper proposes the energy management of reactive power by utilizing the solar photovoltaic (PV) inverter as a static synchronous compensator (PV-STATCOM). Therefore, no other additional flexible AC transmission system controllers or series/shunt capacitors are required. During the islanding mode, the storage provides continuous supply to the load. The system is simulated using single-phase and three-phase modes with the hardware results also revealed. The proposed scheme provides a significant improvement in power factor while reducing the total harmonic distortion.

Multilevel Inverter: A Survey on Classical and Advanced Topologies, Control Schemes, Applications to Power System and Future Prospects

In recent years, multilevel inverters (MLIs) have emerged to be the most empowered power transformation technology for numerous operations such as renewable energy resources (RERs), flexible AC transmission systems (FACTS), electric motor drives, etc. MLI has gained popularity in medium- to high-power operations because of numerous merits such as minimum harmonic contents, less dissipation of power from power electronic switches, and less electromagnetic interference (EMI) at the receiving end. The MLI possesses many essential advantages in comparison to a conventional two-level inverter, such as voltage profile enhancement, increased efficiency of the overall system, the capability of high-quality output generation with the reduced switching frequency, decreased total harmonic distortions (THD) without reducing the power of the inverter and use of very low ratings of the device. Although classical MLIs find their use in various vital key areas, newer MLI configurations have an expanding concern to the limited count of power electronic devices, gate drivers, and isolated DC sources. In this review article, an attempt has been made to focus on various aspects of MLIs such as different configurations, modulation techniques, the concept of new reduced switch count MLI topologies, applications regarding interface with renewable energy, motor drives, and FACTS controller. Further, deep insights for future prospective towards hassle-free addition of MLI technology towards more enhanced application for various fields of the power system have also been discussed. This article is believed to be extremely helpful for academics, researchers, and industrialists working in the direction of MLI technology.

Multi-objective Mathematical Programming to Simultaneously Control SCUC and OUPFC to Improve Power System Controllability

ABSTRACT Security-Constrained Unit Commitment (SCUC) problem and subsequently employing Flexible AC Transmission Systems (FACTS) controllers including Optimal Unified Power Flow Controller (OUPFC) play a crucial role in power systems operation and control in terms of increasing the security of energy transmission networks. The principal objective of the SCUC problem is to acquire the minimum operating cost simultaneously maintaining the security of the system. In this paper, significant attention is paid particularly to simultaneously control SCUC and OUPFC, since energy loss reduction and transmission lines capacity release can be effectively achieved with incorporating SCUC and OUPFC, and subsequently setting the effective variables. In this regard, the SCUC problem with the presence of OUPFC is solved as Nonlinear Programming with Discontinuous Derivatives (DNLP) framework and the proposed algorithm is implemented on two IEEE 14-bus and IEEE 30-bus systems using General Algebraic Modeling System (GAMS) software in order to optimize the total fuel cost, power losses and cost of OUPFC installation as objective functions in the multi-objective framework. The simulation results show the capability of the proposed algorithm to simultaneously determine the optimal location of the OUPFC and its settings in the SCUC problem and to improve the controllability of the power system operation.

Adaptive recurrent NeuroFuzzy control for power system stability in smart cities

A smart city is a dynamic and sustainable urban system that provides a great quality of service to its residents by optimally managing its resources. In smart cities, low-frequency oscillations are a serious concern to the power system as they adversely affect system’s stability. Moreover, power system stabilizers are inefficient due to their fixed-parameter architecture. Flexible ac transmission system controller performs effective damping of low-frequency oscillations when provided with suitable supplementary damping control like a Static synchronous series compensator. In this context, the paper proposes an adaptive neuro-fuzzy recurrent wavelet control for smart cities that uses the recurrent Gaussian membership function and recurrent wavelet neural network in antecedent and consequent parts respectively. The paper applies the gradient descent optimization with a back-propagation algorithm to update the parameters of suggested adaptive neuro-fuzzy recurrent wavelet control. Simulations are performed on two test systems, both showing the effectiveness of the recommended control scheme as compared to traditional lead-lag control and artificial neuro-fuzzy Takagi Sugeno Kang control. Calculations of performance index for various fault scenarios lead to the conclusion that the control scheme can damp oscillations effectively and enhances the power system’s transient stability.