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This paper investigates an optimal methodology for mitigating low-frequency oscillation concerns in power systems. The study explores the synergistic integration of a power system stabilizer (PSS) and a flexible alternating current transmission system (FACTS) to formulate an intelligent controller. A comprehensive analysis encompasses various PSS design strategies, including lead-lag (LL), proportional-derivative-integral (PID), and fractional-order proportional-integral-derivative (FOPID) controllers. The FACTS device selected for this investigation is a static VAR compensator (SVC), highlighting the exceptional efficacy of FOPID-based PSS over alternative strategies with a power oscillation damper. The study extends its scope to encompass a comparative assessment of two distinct optimization algorithms: the moth flame optimization (MFO) and the antlion optimization (ALO). The research is conducted using a single-machine infinite bus power system (SMIB) as the case study platform. A total of four diverse test scenarios are executed under varying operating conditions. The evaluation of the developed method employs six distinct performance indices to investigate the developed controller thoroughly. The outcomes reveal that the MFO-optimized FOPID-PSS and SVC controller outperforms other control schemes. This optimized configuration demonstrates substantial improvements across all performance indices. These findings underscore the superior capabilities of the proposed approach in enhancing power system stability and performance. [ABSTRACT FROM AUTHOR]

The paper presents a ground fault location algorithm (GFLA) in double‐circuit transmission lines (DCTL) with a T‐off connection to an industrial microgrid (IMG) containing electric arc furnaces (EAF), renewable distributed generations (RDG), and static VAR compensator (SVC). The design presented utilizes the information on the current and voltage phasors of one side of the transmission lines (TL) during the fault period, and there is no need for the availability of information on the type of faulty phase(s) and even the faulty section. To find the exact location of the fault in this design, the voltage phasor equations governing the fault point in positive, negative, and zero‐sequence (PNZS) domains, the zero‐sequence current (ZSC) equation of the fault point, and the boundary condition equation of the fault point have been used. The simulation system is implemented in Simulink/MATLAB using accurate modelling of all network components. The algorithm has been tested and evaluated in different fault conditions, including various locations, phase types, phase‐to‐ground connection resistance, occurrence time, and microgrid (MG) operation modes. The successful results of various tests of the proposed design as well as the analysis of various sensitivities confirm the satisfying performance of the suggested algorithm. [ABSTRACT FROM AUTHOR]

Flexible alternating current transmission systems (FACTSs) have been widely incorporated in electric power systems in order to control system parameters. This paper proposes the modeling of four FACTS devices, using the Branch Flow Model (BF) as an optimization problem to reduce the complexity of the Newton–Raphson (NR) load flow code with FACTS devices. The devices are represented as variable impedances, as a function of a firing angle, and as voltage source converters (VSCs) located on the buses and transmission lines. This proposed model solves the problem associated with the selection of appropriate initial conditions of the parameters of each device that guarantee convergence. The model is validated by evaluating its percentage deviation with respect to the NR method, using the standard test systems, IEEE 5-bus, IEEE 14-bus, IEEE 30-bus, and IEEE 57-bus systems. [ABSTRACT FROM AUTHOR]

The importance of flexible alternating current transmission system (FACTS) devices is increasing day by day as they provide compensation for power systems. The installation of such devices solves many issues regarding the stability and power transferability of power systems. However, for optimizing the performance of FACTS devices, the location and sizes of FACTS devices must be selected very carefully. On the other side, the utilization of optimization techniques is increasing daily, as it is capable of solving nonlinear, random problems by its stochastic nature. As a result, it became a reliable tactic for solving stochastic problems almost in every aspect of our lives. Therefore, it is adopted for solving power system problems, like, FACTS devices allocation, distributed generators allocation, determining component's parameters, and more. In this paper, the optimal size and location of several FACTS devices are selected to achieve the following single objective functions separately: fuel cost minimization and power losses minimization, then combining the mentioned objective function into one multiobjective function for gross cost minimization. The power system optimized is the Institute of Electrical and Electronics Engineers 30‐bus standard system, and the FACTS devices installed are static VAR compensator, thyristor control series compensator, and thyristor‐controlled phase shifter, while the optimization is performed using different conventional and recent optimization algorithms, including a newly developed algorithm, typically Leader Walrus Optimization Algorithm "LWaOA," making a comparison among such algorithms to investigate the algorithm that possesses the best performance. The results of the optimization processes show the superiority of LWaOA. [ABSTRACT FROM AUTHOR]

This work focuses on the use of the Linear Quadratic Gaussian (LQG) technique to construct a reliable Static VAr Compensator (SVC), Thyristor Controlled Series Compensator (TCSC), and Excitation System controller for damping Subsynchronous Resonance (SSR) in a power system. There is only one quantifiable feedback signal used by the controller (generator speed deviation). It is also possible to purchase this controller in a reduced-order form. The findings of the robust control are contrasted with those of the "idealistic" full state optimal control. The LQG damping controller's regulator robustness is then strengthened by the application of Loop Transfer Recovery (LTR). Nonlinear power system simulation is used to confirm the resilience of the planned controller and demonstrates how well the regulator dampens power system oscillations. The approach dampens all torsional oscillatory modes quickly while maintaining appropriate control actions, according to simulation results. [ABSTRACT FROM AUTHOR]

The problem regarding the optimal placement and sizing of different FACTS (flexible alternating current transmission systems) in electrical distribution networks is addressed in this research by applying a master–slave optimization approach. The FACTS analyzed correspond to the unified power flow controller (UPFC), the thyristor-controlled shunt compensator (TCSC, also known as the thyristor switched capacitor, or TSC), and the static var compensator (SVC). The master stage is entrusted with defining the location and size of each FACTS device using hybrid discrete-continuous codification through the application of the black widow optimization (BWO) approach. The slave stage corresponds to the successive approximations power flow method based on the admittance grid formulation, which allows determining the expected costs of the energy losses for a one-year operation period. The numerical results in the IEEE 33-, 69-, and 85-bus grids demonstrate that the best FACTS device for locating in distribution networks is the SVC, given that, when compared to the UPFC and the TCSC, it allows for the best possible reduction in the equivalent annual investment and operating cost. A comparative analysis with the General Algebraic Modeling System software, with the aim to solve the exact mixed-integer nonlinear programming model, demonstrated the proposed BWO approach's effectiveness in determining the best location and size for the FACTS in radial distribution networks. Reductions of about 12.63 % and 13.97 % concerning the benchmark cases confirmed that the SVC is the best option for reactive power compensation in distribution grids. [ABSTRACT FROM AUTHOR]

This paper proposes a novel method to find the optimal location of the shunt connected Flexible AC Transmission Systems (FACTS) such as Static Var Compensator (SVC) or Static Synchronous Compensator (STATCOM) to the power system for regulating voltage levels of all buses. Three indices include Voltage Drop Index (VDI), Total Voltage Drop Index (TVDI), and Total Voltage Drop of Network Index (TVDNI) are presented to find the location of the SVC. Also, to minimize the solution space, a ranking list will be established. For the case studies, the IEEE 14-bus test system is selected, and an SVC is located in the system. Simulations are done in two cases: network loads increase with constant coefficient and randomly. According to simulation results in both cases, the proposed method can identify the optimal placement of SVC, and the voltage drop due to increasing the load will be compensated. For the IEEE 14-bus test system, the optimal location of the SVC is bus 9. Variable loads are considered for 24 h, and SVC is installed at bus 9 to validate the introduced method. Results show the voltage level for all buses is compensated so that the voltage levels are higher than the minimum voltage level, i.e. 95%. [ABSTRACT FROM AUTHOR]

The supply of growing electricity demand is possible through continuous technological advances and the expansion of national and international electrical systems. This scenario could introduce voltage drops and consequent changes in the reactive power flow throughout the electrical network. In order to control these problems, various strategies have been developed as a solution to improve the transport and distribution of electrical energy. One of them is the Flexible Alternating Current Transmission System (FACTS), and more specifically the STATic synchronous COMpensator (STATCOM). This paper investigates the influence and effectiveness of STATCOM to mitigate the losses in the transmission lines and its impacts on bus voltage drops. The simulations are performed using the software DIgSILENT PowerFactory and the results showed that STATCOM reduces the power system losses in an interval of 23.86% until 32.86%, and in addition, the STATCOM decreases the annual energy cost by 7.82% in the implemented test case. [ABSTRACT FROM AUTHOR]

Given the concern for maintaining voltage stability in power systems integrated with renewable power systems due to a mismatch in generation and demand, there remains a need to invoke flexible alternating current transmission system (FACTS) devices in the distribution network. The present paper deals with identifying the locations of placement of a static var compensator in an experimental IEEE 14-bus system; the voltage drop in different buses in an IEEE 14-bus system is calculated by the standard formula. The total voltage drop in the network (TVDN) is also calculated as a reference. The ranking of buses in order of decreasing voltage drop is made, and the weak buses are identified as those showing the maximum or near-maximum voltage drop for the installation of a Static Var Compensator (SVC). The optimum usable size is calculated using a Genetic Algorithm approach to optimize the installation cost. After size optimization, installing a 2 MW solar generator is considered for the weak and most potential bus, which suffers from voltage drops or power loss. Based on the generator at the weakest bus, the total power loss in the network is calculated and compared with a similar method to assess the efficiency of the proposed model. Thus, the voltage stability enhancement problem is solved by applying a Genetic algorithm (GA) to optimize SVC size and using the Total Voltage Drop in Network (TVDN) method to identify weak buses in the systems. It is found that the performance of the proposed system is comparable with another existing system. It is further observed that a gain in power loss to 6.56% is achievable by adopting the proposed strategy, and the gain is better than the other system. [ABSTRACT FROM AUTHOR]

Flexible Alternating Current Transmission Systems (FACTS) play a very prominent role in enhancing the performance of power system networks and in the quality up-gradation of power system by stabilizing the system parameters like voltage deviation, system security, power loss and system load-ability being a few to name. This work therefore handles two of the important performance parameters of a power system network namely power flow which is modeled as the System Load-ability (SL) and voltage profile which is represented as Voltage Stability Index (VSI). In this paper the maximization of VSI and SL of IEEE 30 Bus and 57 Bus networks have been exploited through the optimal placement of Thyristor Controlled Series Capacitor (TCSC), Static VAR Compensator (SVC) and Unified Power Flow Controller (UPFC) in the networks using the proposed and enhanced form of a recently developed meta-heuristic technique named as Salp Swarm Optimization (SSO). The outcomes of the simulations have been scrutinized with an established swarm-based optimization procedure. [ABSTRACT FROM AUTHOR]

This study presents a novel improved differential evolutionary (IDE) algorithm for optimizing reactive power management (RPM) problems. The effectiveness of IDE algorithm is tested on different unimodal and multimodal benchmark functions. The objective function of the RPM is considered as the minimization of active power losses. Initially, the power flow analysis approach is employed to detect the optimal position of flexible AC transmission system (FACTS) devices. The proposed method is used to determine the optimal value of control variables such as generator's reactive power generation, transformer tap settings, and reactive power sources. Furthermore, the efficacy of the IDE approach is compared with other promising optimization methods such as variants of differential evolution algorithm, moth flame optimization (MFO), brainstorm‐based optimization algorithm (BSOA), and particle swarm optimization (PSO) on various IEEE standard test bus (i.e., IEEE‐30, ‐57, ‐118, and ‐300) systems with active and reactive loading incorporating FACTS devices. A Static VAR compensator (SVC) for shunt compensation and a thyristor‐controlled series compensator (TCSC) for series compensation were used as FACTS devices. The proposed IDE method significantly reduces the active power loss, that is, 55.65% in IEEE 30, 39.68% in IEEE 57, 16.32% in IEEE 118, and 8.56% in IEEE 300 bus system at nominal loading. Finally, the statistical analysis such as Wilcoxon signed‐rank test (WSRT) and ANOVA test were thoroughly analysed to demonstrate the firmness and accuracy of the proposed technique. [ABSTRACT FROM AUTHOR]

The strategic intent of the African Union is to develop a "Smart Integrated African Electric Power Super Grid" driven by modern tools and advances in high-voltage direct current (HVDC) engineering and flexible alternating current technology systems (FACTS), which is central in supporting Africa's sustained economic growth and development. The southern African region, including South Africa, is beset by the critical challenges of perennial load-shedding, which impedes economic growth and aggravates unemployment. This has led to the insecurity of electricity supplies and degraded the quality of life. The parallel operation of high-voltage direct current (HVDC) and flexible AC technology systems (FACTS) controllers is gaining traction as system conditions become more complex, such as weak power networks which requires increased stability requirements, resulting in load-shedding and power outages. These adversely affect business productivity and adversely affect GDP and economic growth. Thus, the application of innovative technologies such as HVDC links can stabilize weak power systems. It is established that HVDC delivery systems reduce losses in long transmission lines transporting bulk power compared with high-voltage alternating current (HVAC) transmission lines for power wheeling. This paper evaluates the parallel operation of the Cahora Bassa 1414 km bipolar HVDC link and a weak parallel 400/330 kV alternating current (AC) link. It demonstrates the use of FACTS controllers to enhance the technical performance of an existing network, such as voltage control, and technical loss reduction. It combines an HVDC line commutated converter (LCC) and HVAC transmission lines, in hybrid notation to increase the voltage stability of the system by controlling the reactive power with a Static Var Compensator (SVC). These modern tools can increase the transmission power controllability and stability of the power network. In this study, HVDC–LCC was used with a setpoint of 1000 MW in conjunction with the 850 MVAr SVC. The results show that the technical losses were reduced by 0.24% from 84.32 MW to 60.32 MW as Apollo 275 kV SVC was utilized for voltage control. The network analysis was performed using DIgSILENT PowerFactory software that is manufactured by DIgSILENT GmbH at Gomaringen, Germany [ABSTRACT FROM AUTHOR]

Today, Flexible AC Transmission Systems (FACTS) devices provide local reactive power support in load centers and keep bus voltages within safe operating limits. In particular, the single use of parallel FACTS devices may not improve the safe operating conditions of the system depending on the load conditions. Therefore, avoiding parallel FACTS devices' high costs is crucial and determining their optimal places in the system. For this, Static Var Compensator (SVC), one of the parallel FACTS devices, is used. This study investigated the effects of multiple uses of SVC on different load buses on the maximum load parameter of the multi-machine system in a 3-machine 9-bus power system. Moreover, bus-voltage profiles and their changes in active-reactive power are studied in detail. In this study, three analysis methods were used. These are the no SVC, the single use of SVC, and the multiple uses of SVC. The Power Systems Analysis Program (PSAT) was preferred for this simulation study. As a result of the study, using multiple SVCs increases the maximum loading parameter value and improves the bus-voltage profiles and active-reactive power changes compared to others. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A constant worldwide growing load stress over a power system compelled the practice of a reactive power injection to ensure an efficient power network. For this purpose, multiple technologies exist in the knowledge market out of which this paper emphasizes the usage of the flexible alternating current transmission system (FACTS) and presents a comparative study of the static var compensator (SVC) with the static synchronous compensator (STATCOM), inducted in a real electric substation. The aim is to improve the power factor (PF) and power quality and to encounter reliably extreme conditions. A 220 kV electric substation was opted for the analysis, and both the static and dynamic conditions were observed with the help of a power system analysis tool termed PowerFactory-DIgSILENT. Multiple aspects were investigated via software simulations to assess the performance of the aforementioned FACTS devices, such as the voltage profile evaluation via the load flow analysis method (LFA), the harmonic response via the power quality and harmonic analysis tool, and the short-circuit response via the RMS simulation tool. The outcomes were verified and compared with permissible values included in the universal standards, such as IEC and IEEE. The superiority of the STATCOM over the SVC was proven in light of the simulative results. [ABSTRACT FROM AUTHOR]

In this paper, the influence of the Static Var Compensators (SVC) on distance relay protection when connected to the sub-transmission network of the Nigerian 132-kV grid system is investigated. This is carried out by monitoring the error margin of the fault locator associated with the distance protective relays when SVC is connected to the transmission line. The location of the SVC is selected such that there is a common primary source of power to the subtransmission network (Ikorodu-Sagamu 132-kV transmission line) and the SVC, which is a shunt-connected device located on Ikorodu 132-kV bus. The fault is simulated at 33.6 km and 60.4 km respectively from the Ikorodu 132-kV sub-station in MATLAB/ Simulink model and the simulation results obtained are used to investigate the influence of SVC on distance protective relay when connected to the 132-kV power transmission line. The results of the line faults are obtained with respect to earth for both zones one (1) and two (2) when SVC is connected and disconnected for all shunt type of faults. Thus, indicating under-reach and overreach characteristics of the distance relay, when the SVC is connected and disconnected, while the transmission line protection showed no under-reach or over-reach characteristics for line-toline fault for both zones with the SVC connected or disconnected. The results of this study show that though SVCs improve the quality of power to consumers, there is a tendency for underreach and over-reach characteristics of the protective relay to be displayed when the relays are disconnected and connected, which introduces error margins to the fault locator in distance protective relays. Therefore, more detailed dynamic simulations are recommended for reducing the error margin. [ABSTRACT FROM AUTHOR]

The goal of multi-criteria decision making (MCDM) is to select the most appropriate of the alternatives by evaluating many conflicting criteria together. MCDM methods are widely available in the literature and have been used in various energy problems. The key problems studied in electrical power systems in recent years have included voltage instability and voltage collapse. Different flexible alternating current transmission systems (FACTS) equipment has been used for this purpose for decades, increasing voltage stability while enhancing system efficiency, reliability and quality of supply, and offering environmental benefits. Finding the best locations for these devices in terms of voltage stability in actual electrical networks poses a serious problem. Many criteria should be considered when determining the most suitable location for the controller. The aim of this paper is to provide a comparative analysis of MCDM techniques to be used for optimal location of a static VAR compensator (SVC) device in terms of voltage stability. The ideal location can be determined by means of sorting according to priority criteria. The proposed approach was carried out using the Power System Analysis Toolbox (PSAT) in MATLAB in the IEEE 14-bus test system. Using ten different MCDM methods, the most appropriate locations were compared among themselves and a single ranking list was obtained, integrated with the Borda count method, which is a data fusion technique. The application results showed that the methods used are consistent among themselves. It was revealed that the integrated model was an appropriate method that could be used for optimal location selection, providing reliable and satisfactory results to power system planners. [ABSTRACT FROM AUTHOR]

Due to the pattern of growth for electricity consumption, there is a need for developing power networks and transmission lines. The power transmission capacity of lines is limited due to a host of factors. Thus, these lines need series and parallel compensations to reduce losses, increase efficiency, and promote system security. In this paper, flexible alternating current transmission system (FACTS) devices including static VAR compensators (SVC) as parallel compensators, thyristor-controlled series compensation (TCSC) as a series compensator, and high-voltage direct current (HVDC) bonding are modeled. In addition, comprehensive modeling of the simultaneous application of these three devices for load flow is performed, and the effects of these types of compensations are compared. The obtained comprehensive model was implemented on MATLAB software using the Newton–Raphson method on two 9-bus WSCC and 5-bus test system. In this case, the calculation speed and convergence were reduced when compared to applying devices individually due to the increase in equations and the addition of new terms to the load flow equations. Furthermore, more losses were observed in this model, which can probably be improved using an optimal power flow and optimal placement of the devices in the network. [ABSTRACT FROM AUTHOR]

Optimal power flow (OPF) is one of the challenging optimization problems in power domain. The complexity of the problem escalates with incorporation of uncertain and intermittent renewable sources into the electrical network. Flexible AC transmission system (FACTS) devices are also becoming more commonplace in modern power system to mitigate growing demand and to relieve congestion from the network. This paper aims to solve the OPF where the generation cost is optimized with incorporation of stochastic wind power and several types of FACTS devices such as static VAR compensator, thyristor-controlled series compensator and thyristor-controlled phase shifter. Case studies with both fixed and uncertain load demands are performed. The stochastic wind energy and load demand are modeled using suitable probability density functions. Optimization objective considers cost of thermal generation, direct cost of scheduled wind power, penalty cost for underestimation and reserve cost for overestimation of the wind power. In addition, both locations and ratings of the FACTS devices are optimized to minimize total generation cost of the system. Success history-based adaptive differential evolution (SHADE), a powerful evolutionary algorithm, is adopted to perform the optimization task. The constraints of OPF problem are handled using superiority of feasible solutions (SF) method. The integration approach of SF method with several popular metaheuristic algorithms has been proposed in this work, and a detailed comparative analysis among various algorithms establishes SHADE algorithm to be the best performer. [ABSTRACT FROM AUTHOR]

In this paper, Improved Moth Flame Optimization (IMFO) algorithm is implemented to restore power flow solvability by transferring of adequate amount of load shedding (LS) through the power system. Shunt Flexible Alternating Current Transmission System (FACTS) devices including Static VAR Compensator (SVC) and Static Synchronous Compensator (STATCOM) are incorporated with the system for obtaining better reactive power support. Maximum power system loadability is obtained using Continuation Power Flow (CPF). Both of normal operation and contingency conditions for generator and bus outages are considered for the fruition of the validity of the suggested method to operate under various conditions. The proposed approach is validated using IEEE-30 bus standard test system. The obtained results manifest the capability of the suggested method to reduce the LS values leading to continuous service to the customers and the capability of preventing voltage collapse and restore the bus voltages to the permissible limits. The emulation results reveal the effectiveness of the suggested method for enhancement of the power system loadability. [ABSTRACT FROM AUTHOR]

This paper presents the application of Flexible Alternating Current Transmission System (FACTS) devices based on heuristic algorithms in power systems. The work proposes the Autonomous Groups Particle Swarm Optimization (AGPSO) approach for the optimal placement and sizing of the Static Var Compensator (SVC) to minimize the total active power losses in transmission lines. A comparative study is conducted with other heuristic optimization algorithms such as Particle Swarm Optimization (PSO), Timevarying Acceleration Coefficients PSO (TACPSO), Improved PSO (IPSO), Modified PSO (MPSO), and Moth-Flam Optimization (MFO) algorithms to confirm the efficacy of the proposed algorithm. Computer simulations have been carried out on MATLAB with the MATPOWER additional package to evaluate the performance of the AGPSO algorithm on the IEEE 14 and 30 bus systems. The simulation results show that the proposed algorithm offers the best performance among all algorithms with the lowest active power losses and the highest convergence rate. [ABSTRACT FROM AUTHOR]

This study introduces a techno-economic planning strategy of reactive power (VAr) in power transmission systems. This planning strategy primarily has been focused on reactive power planning (RPP) through operating cost minimisation ensuring cost-oriented system security. The objective function (operating cost) is blended with four different components viz. cost due to real power loss, VAr generation cost, additional VAr compensation devices cost and line charging cost. FACTS (flexible AC transmission system) devices are installed at weak positions through different echelons to improve the system voltage stability. The authors also implemented the probabilistic hybridisation of crow search algorithm and JAYA to find out the optimal set of controlling parameters related to VAr. Finally, a sharp and minute analysis of the results has been done to validate the proposed strategy under multi-loading conditions. To understand the efficiency and efficacy the code profiling and simulation has been rendered on IEEE 30 bus and UPSEB 75 bus test system. [ABSTRACT FROM AUTHOR]

This study introduces a techno‐economic planning strategy of reactive power (VAr) in power transmission systems. This planning strategy primarily has been focused on reactive power planning (RPP) through operating cost minimisation ensuring cost‐oriented system security. The objective function (operating cost) is blended with four different components viz. cost due to real power loss, VAr generation cost, additional VAr compensation devices cost and line charging cost. FACTS (flexible AC transmission system) devices are installed at weak positions through different echelons to improve the system voltage stability. The authors also implemented the probabilistic hybridisation of crow search algorithm and JAYA to find out the optimal set of controlling parameters related to VAr. Finally, a sharp and minute analysis of the results has been done to validate the proposed strategy under multi‐loading conditions. To understand the efficiency and efficacy the code profiling and simulation has been rendered on IEEE 30 bus and UPSEB 75 bus test system. [ABSTRACT FROM AUTHOR]

To relieve congestion due to open‐access feature in competitive power system framework, utilities plan flexible alternating current transmission systems (FACTS), ensuring improved utilization and performance of the transmission infrastructure. However, high‐investment cost restricts implementation to single type of FACTS' planning in a time. Therefore, successive planning of another FACTS to delay transmission expansion results in multi‐type FACTS planning. Consequently, to optimise performance, subsequent planning must coordinate with existing FACTS. The main objective of this study is to implement coordination of multi‐type FACTS for available transfer capability (ATC) enhancement. A hybrid real power flow performance index (PI) and particle swarm optimisation (PSO), coordinate thyristor control series compensator (TCSC) in the first planning horizon with static synchronous series compensator (SSSC) and unified power flow controller (UPFC), in the second horizon. The PI–PSO‐based multi‐type FACTS coordination improves ATC of multilateral power transfers in a standard 9‐buses test network. Results show that multi‐type FACTS achieved higher ATC; such that enhanced ATC by TCSC–SSSC ranges between 8.06–69.34% while the TCSC–UPFC ranges between 11.85–71.59% for various power transfer transactions. A comparison of the three coordination schemes shows that the scheme with more decision parameters provides superior loadability and transfer capability improvement. [ABSTRACT FROM AUTHOR]

Transient Stability is the capability of a system to be able to return to its normal state after experiencing large disturbances. The static var compensator (SVC) is a shunt device of the flexible AC transmission systems (FACTS) family using power electronics to improve transient stability in power system. For the SVC control, it is usually used a PI controller, although PI controller is simpler and cheaper but not suitable when power system is subjected to transient stability since power system become non-linear system. In order to overcome this problem, the PI controller combined with Fuzzy controller is designed. Two types of faults were considered for this study to examine the effect of the fuzzy-SVC controller on system transient stability, the proposed fault types are single line to ground fault and three lines to ground fault. The performance and behavior of the designed fuzzy controller compared with that of the conventional PI controller in term of terminal voltage, rotor angle, and transmission line active power. [ABSTRACT FROM AUTHOR]

Within substations installed with flexible ac transmission systems, the magnetic flux leakage (MFL) generated by air core reactors in static var compensator (SVC) can be very high. To reduce the influence of the high magnetic field, an optimal suppression method is selected based on fuzzy comprehensive evaluation. First, a series of onsite measurements are performed around the reactors in the SVC. From the measurement results, the low-voltage cables, dc system, grounding grid, and magnetic flux density around the air core reactors are seriously affected by the MFL generated by the air core reactors with currents of a few kiloamperes. Then, according to the actual parameters of the air core reactors, a three-dimensional simulation model is constructed using the finite-element method (FEM) to calculate the magnetic flux density and some parameters related to the magnetic field. Moreover, four different suppression methods are proposed to suppress the MFL influence. Due to the multiple aspects affected by MFL, it is always difficult to make a quantitative comparison for the suppression methods based on previous research. For this reason, a fuzzy comprehensive evaluation method based on a linear evaluation model is proposed to quantitatively compare the suppression methods by using the suppression effect value δ. In a comparison of different suppression methods, the aluminum plate shielding with proper parameters has prove to be an optimal method for achieving a comprehensive suppression effect. The modeling and evaluation methods presented in this article are both valuable to solve the complex MFL influence problem in different SVC-based substations. [ABSTRACT FROM AUTHOR]

The increased power system loading combined with the worldwide power industry deregulation requires more reliable and efficient control of the power flow and network stability. Flexible AC transmission systems (FACTS) devices give new opportunities for controlling power and enhancing the usable capacity of the existing transmission lines. This paper presents a combined application of the particle swarm optimization (PSO) and the continuation power flow (CPF) technique to determine the optimal placement of static var compensator (SVC) in order to achieve the static voltage stability margin. The PSO objective function to be maximized is the loading factor to modify the load powers. In this scope, two SVC constraints are considered: the reference voltage in the first case and the total reactance and SVC reactive power in the second case. To test the performance of the proposed method, several simulations were performed on IEEE 30-Bus test systems. The results obtained show the effectiveness of the proposed method to find the optimal placement of the static var compensator and the improvement of the voltage stability. [ABSTRACT FROM AUTHOR]

In this study, a maiden application of cascade proportional–integral–derivative with filter (PIDF) and one plus fractional-order derivative (1+FOD), i.e. PIDF(1+FOD) controller is proposed for the load frequency control mechanism. The main purpose of the cascade and fractional order controller is to increase the degree of freedom and reject the disturbances faster. A novel attempt has also been made to model a static synchronous series compensator (SSSC) with AC tie-line and HVDC tie-line. Here SSSC and HVDC tie-line are used to regulate and increase the power transfer capabilities between interconnected areas. Furthermore stored energy in the HVDC tie-line is utilised to improve the system dynamics by inertia emulation control strategy. An evolutionary salp swarm algorithm-based optimisation technique is adopted to optimise control parameters. The performance of the proposed controller is tested on a two-area hydro-thermal interconnected power system in deregulated environment. First, the effectiveness AC–DC-SSSC tie line is shown over AC-SSSC and alone AC tie-line with proposed PIDF(1+FOD) controller followed by the supremacy of proposed PIDF(1+FOD) over classical controllers. Finally, sensitivity is analysed by variation in system parameters, which shows the robustness of the proposed controller. [ABSTRACT FROM AUTHOR]

In this study, a maiden application of cascade proportional–integral–derivative with filter (PIDF) and one plus fractional‐order derivative (1+FOD), i.e. PIDF(1+FOD) controller is proposed for the load frequency control mechanism. The main purpose of the cascade and fractional order controller is to increase the degree of freedom and reject the disturbances faster. A novel attempt has also been made to model a static synchronous series compensator (SSSC) with AC tie‐line and HVDC tie‐line. Here SSSC and HVDC tie‐line are used to regulate and increase the power transfer capabilities between interconnected areas. Furthermore stored energy in the HVDC tie‐line is utilised to improve the system dynamics by inertia emulation control strategy. An evolutionary salp swarm algorithm‐based optimisation technique is adopted to optimise control parameters. The performance of the proposed controller is tested on a two‐area hydro‐thermal interconnected power system in deregulated environment. First, the effectiveness AC–DC‐SSSC tie line is shown over AC‐SSSC and alone AC tie‐line with proposed PIDF(1+FOD) controller followed by the supremacy of proposed PIDF(1+FOD) over classical controllers. Finally, sensitivity is analysed by variation in system parameters, which shows the robustness of the proposed controller. [ABSTRACT FROM AUTHOR]

Flexible AC transmission systems (FACTS) technology is widely adopted and utilized to maintain the performance of power systems. However, the improvements of power system performance achieved by FACTS devices depend on the right sizing and allocation of such devices. For technical and economic considerations, a FACTS device's location and size should be selected very carefully in order to maximize its benefits to the power system. In this paper, the sizing and location of a static VAR compensator (SVC) are optimally determined using a new optimization technique called lightning attachment procedure optimization (LAPO). The optimal allocation of the SVC is determined regarding the improvement of voltage deviation index and the reduction of total active power losses. The system is optimized in two cases: once without SVC installation in order to find out the optimal settings of the system that achieve the objective functions, and another time with SVC installation to determine its optimum sizes and locations by which the required objective functions are achieved. Then the system performance is analyzed after optimization with and without SVC devices to show the impact of the optimum sizing and location of the SVC on the system. The study is validated using the standard IEEE 30-bus system, while the developed LAPO is performed by MATLAB M-Files and the system performance analysis in different cases is performed by NEPLAN software. [ABSTRACT FROM AUTHOR]

This paper presents a novel hybrid algorithm that includes the superior properties of strong algorithms which have been developed in recent past. The study involves minimization of transmission loss in IEEE networks through the efficient placement of flexible alternating current transmission system (FACTS) devices. In this work two types of devices namely thyristor controlled series compensator (TCSC) and static VAR compensator (SVC) are used in IEEE 14 bus and IEEE 30 bus systems. The main objective of active power loss reduction is achieved through the minimization of installation cost of these devices which is considered as the fitness function for the optimization algorithms. In this paper Moth flame optimization (MFO) in its natural form as well as in hybrid form called JAYA blended MFO (JMFO) is applied for the study. The results obtained are compared with existing technique like particle swarm optimization (PSO). [ABSTRACT FROM AUTHOR]

Efficient utilization of power networks under extreme voltage sags and swells and reducing the losses are widely recognized as the most important issues in energy industry. Power electronic converter based flexible AC transmission system (FACTS) devices play a significant role in power flow control, power quality improvement, voltage regulation and efficient energy utilization. Distribution static synchronous series compensator (D-STATCOM) is a FACTS device and it compensates for voltage sags and swells by injecting or absorbing reactive power to/from the power network. Modulation of D-STATCOMs is mostly based on pulse width modulation (PWM) techniques and space vector PWM (SV-PWM) is attracting considerable interest due to its better DC utilization and wide linear modulation range. In this paper, a threelevel SV-PWM is suggested for the modulation of D-STATCOM which is based on a three-phase diode-clamped inverter (DCI). A grid connected three-phase power system feeding a 1 MW and 500 kvar load is designed in simulation environment and D-STATCOM is tested under voltage sags and swells occurring on the generation side. Results demonstrate that D-STATCOM successfully injects/absorbs reactive power to/from the system under fluctuating grid conditions. [ABSTRACT FROM AUTHOR]

Flexible AC Transmission Systems (FACTS) present a decision to issue trouble relief for over-extended electric power transmission lines as a result of optimal power flow (OPF) by controlling. To keep away from conventional impacts among a few gadgets placed in a similar grid, an organized control is fundamental. To defeat the issues which happen in optimal power flow to actualize the cross difference progression and coordination inspects strategy, a supervisory controller giving difference progression power flow with numerous destinations is acquired for avoiding congestion, it gives secure transmission and farthest point dynamic power misfortunes. There is no information on gadgets that have been defined in this systematic control of Thyristor controlled series capacitor (TCSC) and Thyristor controlled phase shifting Transformer (TCPST), static VAR compensator (SVC), all of these compensators providing efficient improvements and situations are described. Different optimization techniques are used as a part of the character to deal with the problem of OPF. In some experimental works, the upgrade method is used for finding out all of the fuel costs or the environmental pollution that occurs during the generation of energy. However, in some further research actions, FACTS controlled devices are used to develop the flow of electricity without considering the cost of electricity generation. While a specific end goal of using the FACTS control devices is to help optimize the congestion in the power system, it also aggregates the power loss which enhances the load capacity of the structure. The FACTS and its practical limitations are executed into the IEEE 30-bus test power framework and customized utilizing the Cross Difference Progression and Coordination Examining (CDP&CE) algorithm with MATLAB and the outcomes are given. Here, IoT-based data analytics is defined as the process, which is used to examine varied data from the bus system using Principal Component Analysis (PCA) method, the results of which help to take the necessary decisions. The effect of FACTS gadgets is implemented on standard IEEE-30 transmission framework with supporting numerical outcomes by utilizing MATLAB Software. [ABSTRACT FROM AUTHOR]

Optimal reactive power dispatch is one of the key factors to attain cost-effective and stable functioning of power system. It is a complicated non-linear optimization issue with a combination of discrete and continuous control variables. Due to this complex feature of optimal reactive power dispatch, optimization technique has become an efficient method to solve this problem. In this work, Kinetic Gas Molecule Optimization algorithm with Pareto optimality is proposed for solving multi-objective optimal reactive power dispatch problem. The presentation of Kinetic Gas Molecule Optimization is improved by computing inertia weight and acceleration coefficients dynamically rather than a fixed value. Because of this reason, the searching capability of the particles in each iteration is improved. However, to improve the power system performance in optimal reactive power dispatch scenario, additional flexible AC transmission system devices like static VAR compensator, thyristor-controlled series compensator, and unified power flow controller are introduced to provide stable results when compared to conventional output because flexible AC transmission system devices are capable of controlling the flow of real power and reactive power. These details are implemented and tested on IEEE 30-bus test system with various objectives. The performance of proposed method is validated from MATLAB, which shows the value of power loss as 4.3583 and voltage deviation as 0.26499 with cost of US$469.6417 per MVAR, which shows considerably superior results when compared with implemented particle swarm optimization results. The proposed method provides an efficient result for solving multi-objective optimal reactive power dispatch issues. [ABSTRACT FROM AUTHOR]

A valid damping of oscillations is an upcoming extensive challenge while maintaining the stability of the power system. This oscillation generally occurs due to the fluctuation raised, when two systems are interconnected. This paper addresses the oscillation occurred in the power system as the main challenge, which thus performs an effective simulation in 68-bus system. Here, it promotes a sufficient CC with two FACTS devices such as TCSC and UPFC, which are connected with PSS. Further, it adopts firefly algorithm to enable the CC among the FACTS devices. To the next of the simulation, this paper compares the performance of the FF- CC with conventional optimisations include GSO, PSO, GA and ABC algorithms to enable CC. Further, it provides a detailed analysis of the impact of PSS and loading effects on CC. As a result, the performance of FF-CC hands over the stable power system with powerful damping of oscillations, after comparing it with the existing methods. Abbreviations: ABC, Artificial Bee Colony; ICA, Imperialist Competitive Algorithm; AVR, Automatic Voltage Regulators; NETS, New England test system; BFOA, Bacteria Foraging Optimization Algorithm; NYPS, New York power system; BSO, Bacterial Swarm Optimization; PSO, Particle Swarm Optimization; CC, Coordinated Control; PSS, Power System Stabilizers; COA, Chaotic Optimization Algorithm; STATCOM, Static Synchronous Compensator; CS, Cuckoo Search; SSSC, Static Synchronous Series Compensator; FACTS, Flexible Alternating Current Transmission System; SVC, Static Var Compensator; GA, Genetic Algorithm; TCSC, Thyristor Controlled Series Capacitor; GSO, Gravitational Search Algorithm; UPFC, Unified Power Flow Controller [ABSTRACT FROM AUTHOR]

The concern for ever-increasing demand for electricity, progressive depletion of fossil fuels, reduction in carbon footprint, improved infrastructure reliability, etc. have encouraged the power utility companies to adopt renewable energy sources in conventional power systems. The enhanced penetration of non-dispatchable renewable energy sources such as solar photovoltaic (PV) and wind energy into existing distribution and transmission networks had led to various issues of concern regarding system voltage stability. This paper presents the important issues such as voltage stability based optimum locations and sizing of distributed generation (DG) units, voltage stability assessment, and improvement techniques. The impact of power system devices such as fixed capacitors, flexible AC transmission system (FACTS), and energy storage system (ESS) on voltage stability of transmission and distribution networks are also investigated. The review results provide a comprehensive background for the voltage stability investigation in non-dispatchable renewable integrated power systems with major outcomes and findings of future research work in the field of power system stability. [ABSTRACT FROM AUTHOR]

Low-frequency electromechanical oscillations damping is powerfully crucial in power system operation. In order to fulfill this requirement, power oscillation damping (POD) controllers are installed in synchronous generators and flexible alternating current transmission system devices. These controllers can have either a conventional fixed structure composed by stages of gain and phase compensation or a multi-band modern structure (PSS4B) composed by three bands that correspond to a specific frequency range (low, intermediate and high frequency). In the PSS4B structure, each band consists of two branches based on differential filters (with a gain, lead–lag blocks and a hybrid block). This paper investigates the application of PSS4B as a POD controller for the static VAR compensator (PSS4B-SVC-POD) to damp oscillations in multi-machine power systems. The proposed PSS4B-SVC-POD and power system stabilizers (fitted on generators) are simultaneously designed through an optimization approach aiming at maximizing the closed-loop damping ratio. Modal analysis, frequency responses and time simulations for the well-known two-area four-generator power system show the good performance of the proposed controller fitted on static VAR compensator. [ABSTRACT FROM AUTHOR]

This study analyzed the effects of applications of flexible alternating current transmission system (FACTS) devices, such as a thyristor controlled series capacitor (TCSC) and static var compensator (SVC) to handle the oscillations due to wind penetration in an existing network, and to exploit the AC lines to their thermal limits. A small signal stability analysis of an interconnected power system with wind penetration in the presence of FACTS and a power system stabilizer (PSS) was studied under a diverse range of operating conditions. The coordinated tuning of SVC and PSS parameters as well as a TCSC in the presence of a wind energy conversion system was analyzed. The salp swarm algorithm, a recently developed meta-heuristic approach, was used for tuning TCSC, SVC, and PSS parameters. The supremacy of TCSC over SVC for improving system stability was demonstrated under a diverse range of operating conditions. [ABSTRACT FROM AUTHOR]

Power quality is often defined as the electrical network's or the grid's capability to deliver a clean and stable power supply. Flexible AC transmission systems (FACTS) devices consist of power electronics circuits that's depend on the thyristor for controlling active and reactive power flows and to maintain the voltage within the allowable limits in normal and abnormal operating conditions. Static Var Compensation (SVC) is one of the most important FACTS devices, that's combined between shunt capacitor and shunt reactor, that's connect with the system by control setting. The control of reactive power by SVC module is depending on firing angle of thyristors. The shunt capacitor module can be called thyristor switched capacitors (TSC) and thyristor-controlled reactors (TCR), that's provide harmonic filters and/or dynamic shunt compensation. TSC operates with series bi-directional thyristor and a damping reactor to prevent the shunt resonance, the thyristors are used to control the capacitor to operate at the required value. TCR operates with series thyristor switch for control. SVC is easy and more accurate to operate with the medium voltage. SVC can be connected with the extra high voltage system via step-down transformer. This paper discusses the SVC to be uses to improve the power system quality, by adding the reactive power to the system. Also, this paper discusses the SVC control by using the MATLAB/Simulink software to discuss the step operation for the SVC with the power system. [ABSTRACT FROM AUTHOR]

Hydro‐Québec has identified wide‐area control system as a key initiative able to significantly increase the voltage stability of its grid. In this context, an innovative project for wide‐area and local voltage control of shunt compensators was initiated. Its main objective is to implement a closed‐loop control system on Hydro‐Québec's network to optimise the reactive power support from the dynamic shunt compensators. The outcome of this project is the 'global and local control of compensators' (GLCCs) system which is based on synchrophasor technology and intelligent electronics devices. Applied to each shunt compensator of Hydro‐Québec's network, this robust voltage control system measures voltage variations in the load area and adjusts the operation set point of each shunt compensator accordingly, thus avoiding voltage collapse resulting from extreme contingencies. The GLCC control solution was intensively tested in simulation using PSSE software. Moreover, a pilot project was commissioned on a test bench replica of the system and also tested in real time using Hydro‐Québec's Hypersim digital simulator. Field tests of the GLCC were conducted on a −230/ + 660 MVars static vars compensator. The results of this pilot project were deemed conclusive and the deployment of the new voltage control system has been initiated by Hydro‐Québec. [ABSTRACT FROM AUTHOR]

Development of appropriate load flow model of Flexible AC Transmission System (FACTS) devices is an important issue for proper planning, control, and protection of power system. Holomorphic Embedding Load-Flow Method (HELM) is a novel technique for solving load flow nonlinear equations which overcomes the numerical problems faced by traditional iterative techniques. In order to evaluate the effects of FACTS devices in load flow problem by HELM technique, it is necessary to develop HELM modeling of these devices. This paper presents HELM modeling of Thyristor-based FACTS controllers, i.e., Static Var Compensator (SVC), Thyristor Controlled Switched Capacitor (TCSC), Thyristor Controlled Voltage Regulator (TCVR), and Thyristor Controlled Phase Angle Regulator (TCPAR). In this modeling, white germ solution is investigated along with recursive formula and controlling FACTS devices operation bounds. [ABSTRACT FROM PUBLISHER]

The static VAR generator (SVG) is an important device in flexible AC transmission systems (FACTS) for the development of smart grids. Based on the basis principle of SVG and instantaneous reactive power theory, the conventional ip-iq and dq methods have a certain error when the three phase voltages are unbalanced. In this paper, the current detection algorithm is improved in cases of three-phase power asymmetry by using the fundamental positive-sequence reactive current instead of the voltage as the input of phase locked loop (PLL). So the problems caused by unbalanced three-phase voltages could be avoided. In addition, a moving average filter is designed to improve the performance of the detection accuracy and dynamic response. Experiments verify the correctness and effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

This study presents a novel interfacing setup for testing and validating wide‐area monitoring and control (WAMC) techniques used in smart grids. The main purpose of this study is to provide a realistic approach for conducting WAMC studies. In here, a wide‐area controller (WAC) for a flexible AC transmission system (FACTS) device is implemented. The measurements for the WAC are collected using phasor measurements units (PMUs). Three main segments are being interfaced in this study. First, the real‐power grid, the local area controller of the actual FACTS device, and the PMUs are simulated using real‐time digital simulator. This simulation represents the central simulation and is interfaced with the WAC, which is realised using a MATLAB‐based program. This interface represents a novel software‐in‐the‐loop (SIL) scheme. On the other hand, an actual FACTS device is designed and interfaced to the central simulation via hardware‐in‐the‐loop (HIL) scheme. This SIL and HIL combination makes the experimental testbed more realistic and closer to the industrial standard. Various tests are conducted to examine the performance of the developed testbed. [ABSTRACT FROM AUTHOR]

Based on cascaded ac–ac converter with controllable phase and amplitude (ACCPA), a novel π model ACCPA was proposed for power flow control, whose output voltage phase and amplitude can be regulated, respectively, and simultaneously with respect to the input voltage. Single-phase π model ACCPA comprises a buck-type ac unit, a third harmonic trap and a boost-type ac converter. Compared with single-phase cascaded ACCPA, it has a more simplified structure by dispensing with the LC output filter of the buck-type ac converter, and can adopt the same two-stage duty-cycle modulation. The buck-type ac unit regulates the phase of output voltage and the boost-type ac converter does the amplitude. By utilizing impedance compensation with capacitance in single-phase π model ACCPA, it is effective to counteract or reduce the lag effect which is put on fundamental voltage by line impedance of third harmonic trap and inductance. Three-phase π model ACCPA comprises three buck-type ac units and a three-phase boost-type ac converter, it not only dispenses with three LC output filters, but also does three third harmonic traps, so it has simple structure. Experimental results verified the feasibility of π model ACCPA and the correctness of its theory. [ABSTRACT FROM PUBLISHER]

Static synchronous compensator (STATCOM), a shunt type flexible AC transmission system device, is used to control the voltage at different locations within a power system by absorbing/injecting reactive power. The dynamic control action associated with the operation of STATCOM in both capacitive and inductive modes is the reason for varying system condition and failure of different relaying schemes. Directional relaying is affected by the reactive current contributed by STATCOM in wide range of inductive to capacitive mode of operation. Further, single pole tripping (SPT) condition during STATCOM operation leads to mal‐function of the directional element due to phase change in sequence components of voltage and current. In this study, directional relaying is addressed for different types of faults in the presence of STATCOM connected at different locations during single phase auto reclosing period. Proposed directional relaying technique is based on the phase angle between positive sequence fault and pre‐fault apparent powers. Performance of the proposed scheme has been investigated for different types of faults for single and double circuit lines during SPT using simulated data of different power networks using PSCAD/EMTDC software. A comparative study is also carried out to verify the performance of the proposed scheme for different STATCOM operating conditions. [ABSTRACT FROM AUTHOR]

This study investigates the impact of different flexible AC transmission system (FACTS) devices on critical power quality (PQ) phenomena including voltage sags, harmonics and unbalance from the perspective of both mitigation effect and potential negative impact. The FACTS devices, including static VAR compensator, static compensator (STATCOM) and dynamic voltage restorers, are modelled in commercially available software PowerFactory/DIgSILENT to study their impacts on the critical PQ phenomena. Two control strategies, voltage regulation and reactive power compensation, are considered for STATCOM. For DVR, a PI‐controller is developed for the purpose of voltage sag mitigation. The merit of the proposed controller is presented by the dynamic response of during fault voltage and the capability of post‐fault voltage recovery. The study is carried out on a large‐scale generic distribution network. The impact of various devices on PQ phenomena is assessed using appropriate evaluation methodologies, and the results obtained with and without mitigation are presented and compared using heatmaps. [ABSTRACT FROM AUTHOR]

Catastrophic circumstances and equipment failures continue to occur due to Ferroresonance even though this phenomenon has been extensively investigated since, many years ago. This study enhances mitigation of Ferroresonance by means of Flexible AC Transmission System. Static var compensator is used to suppress Ferroresonance along with controlling voltage and reactive power in the network. Manitoba Hydro 230 kV electrical network has experienced Ferroresonant states several times. In this paper, by means of PSCAD/EMTDC simulation software, Ferroresonant states are recognized and analyzed in Manitoba Hydro network. Ferroresonant states are classified in adequate modes by Ferroresonance detection tools. Power and control circuit of SVC is designed and Ferroresonant states are examined in presence of SVC. [ABSTRACT FROM AUTHOR]