Thyristor Controlled Series Capacitor Research Articles

Optimal Setting of Thyristor Controlled Series Compensator with Brain Storm Optimization Algorithms for Available Transfer Capability Enhancement

Applications of Flexible AC Transmission Systems (FACTS) devices for enhancement of Available Transfer Capability (ATC) is gaining attention due to economic and technical limits of the conventional methods involving physical network expansions. FACTS allocation which is sine-qua-non to its performance is a major problem and it is being addressed in recent time with heuristic algorithms. Brain Storm Optimization Algorithms (BSOA) is a new heuristic and predicting optimization algorithms which revolutionizes human brainstorming process. BSOA is engaged for the optimum setting of FACTS devices for enhancement of ATC of a deregulated electrical power system network in this study. ATC enhancement, bus voltage deviation minimization and real power loss regulation are formulated into multi-objective problems for FACTS allocation purposes. Thyristor Controlled Series Capacitor (TCSC) is considered for simulation and analyses because of its fitness for active power control among other usefulness. ATC values are obtained for both normal and N-1-line outage contingency cases and these values are enhanced for different bilateral and multilateral power transactions. IEEE 30 Bus system is used for demonstration of the effectiveness of this approach in a Matlab software environment. Obtained enhanced ATC values for different transactions during normal evaluation cases are then compared with enhanced ATC values obtained with Particle Swarm Optimization (PSO) set TCSC technique under same trading. BSO behaved much like PSO throughout the achievements of other set objectives but performed better in ATC enhancement with 27.12 MW and 5.24 MW increase above enhanced ATC values achieved by the latter. The comparative of set objectives values relative to that obtained with PSO methods depict suitability and advantages of BSOA technique.

Impact of energy storage and flexible alternating current transmission devices in combined voltage and frequency regulation of multiarea multisource interconnected power system

AbstractThis article emphasizes the impact of coordinated energy storage (ES) and flexible alternating current transmission (FACTS) devices in the combined voltage and frequency control of multi‐area systems having hydro, thermal, geothermal, and solar thermal power plants. Appropriate realistic constraints are equipped with both hydro and thermal units. A novel fuzzy logic controller‐based cascade PI and PID with filter coefficient (N), FCPI‐PIDN controller is proposed and optimized various controller parameters using artificial flora algorithm. Comparative analysis of FCPI‐PIDN, Cascade PI and PIDN (CPI‐PIDN), and PIDN controllers show the superiority of the FCPI‐PIDN controller to others. Integration of ES devices (ESDs), such as redox flow battery (RFB), capacitive energy storage (CES), and superconducting magnetic energy storage (SMES) indicates that the incorporation of ESDs enhance the system performance and RFB is superior to SMES and CES. Moreover, integration of FACTS devices, such as interline power flow controller (IPFC), thyristor control series capacitor (TCSC), and unified power flow controller (UPFC) indicates the incorporation of FACTS devices improve the system dynamic and coordination of IPFC‐RFB provide better response than TCSC‐RFB and UPFC‐RFB. Investigation reveals that the optimal location of RFB is Area 1 and IPFC is in between Areas 1 and 3. Sensitivity analysis validated the robustness of the FCPI‐PIDN controller.

Simultaneous controllers for stabilizing the frequency changes in deregulated power system using moth flame optimization

This paper introduces a stochastic idea for two-area automatic generation control (AGC) of the restructured system for enhancing the system dynamic performance. In this work, a new 2-degree of freedom of proportional-integral derivative-fractional order proportional derivative with filter (2DOF PID-FOPDN) approach is proposed for the AGC two area system. To ensure realization of optimal gains of the controller, a novel nature-inspired moth-flame optimization (MFO) is suggested using integral of time multiplied absolute error (ITAE) model. The performance of MFO-based 2DOF PID-FOPDN is evaluated against Cuckoo search (CS), Bat algorithm (BA), and Teaching learning-based optimization (TLBO) approaches in different contract scenarios of deregulated system. Further work to reduce the changes in tie-line has been applied through different FACTS controllers, such as Distributed power flow controller (DPFC), Thyristor-controlled series capacitor (TCSC), Unified power flow controller (UPFC), and Static synchronous series compensator (SSSC); integrated into the AGC system with the co-ordination of Ultra-capacitor (UC). The results indicate that the MFO-based 2DOF PID-FOPDN shows superior performance with DPFC-UC over other approaches in all contract scenarios of liberalized system. A sensitivity analysis is examined to recognize the robustness of the suggested approach under ± 25% deviation in loading and system parameters.

Faulted‐phase identification scheme for series‐compensated transmission lines during the power swing

To perform a fast faulted-phase selection under the power swing in a series compensated line with a thyristor-controlled series capacitor (TCSC) is an extreme challenge facing the transmission line protection schemes. Thus, this paper proposes a new scheme for recognizing the faulted-phase in TCSC-compensated transmission lines during the power swing. Primarily, the fault feature is extracted by using a modified Interclass correlation coefficient. The scheme utilizes the system-current samples during the fault period and system-current samples during the health state as two variables for obtaining the modified interclass correlation coefficient. Then a cumulative approach is used to enlarge the fault feature. The proposed scheme has been subjected to a wide variety of tests through different faults circumstances under different compensation levels. The experimental results have shown good performance against the high impedance/resistance fault under different TCSC-compensation levels during the power swing. Also, the results showed a distinction in terms of time response due to its simple computation process.

Series FACTS controllers in industrial low voltage electrical distribution networks for reducing fault current levels

In this paper, series FACTS devices like Thyristor control series capacitor(TCSC)and Static synchronous series compensator (SSSC) with designed control logic used to reduce the fault current located in LV distribution network at the LV busbar. The electrical distribution network in small and medium scale industries such as steel plants, process and power plants is through low voltage switchgear (LVS) fed from motor control centre (MCC) switchgear through step down transformer of 11kV or 33kV /415V. The designed switchgear in the LV side for these utilities usually is at 50kA. However, the process loads are continuously increasing and sustained with additional feeders with the existing switchgear. Consequently, the fault current at the busbar of the switchgear increases which may require the replacement of entire switchgear to the new design fault current. However, upgrading the existing switchgear is not an economical solution to the industries. Alternatively reducing the fault current at the busbar is feasible. Controller design implemented for reducing the short circuit current with series FACTS devices. A study carried on 800 MW Thermal power plant Ash handling LVS in ETAP and Matlab. It is observed that the results are encouraging to use series FACTS devices effectively in the LVS.

Enhancement of power system transient stability and voltage regulation performance with decentralized synergetic TCSC controller

In this paper, a new nonlinear control approach for thyristor-controlled series capacitors (TCSCs) has been proposed to schedule TCSC line active power transfer, improving transient stability, and obtain acceptable voltage regulation performance of the power system. This control method for the TSCS has been presented based on synergetic control theory. According to the control targets, a linear combination of the TCSC voltage variation, generator rotor speed, TCSC active power, and TCSC reactance is chosen to design a decentralized synergetic TCSC controller (DSTC). A dynamic parameter adaption approach is also presented for updating the DSTC parameters to satisfy control objectives under different power system operating conditions. In the studied system, each generator is equipped with a decentralized improved synergetic excitation controller (ISEC). Dynamic characteristic of the presented DSTC is studied in a single machine infinitive bus and a WSCC-type 3-machine 9-bus power system. A restructured improved synergetic excitation controller (RISEC) has also been formulated to investigate the impact of ISEC on the multi-machine system. Simulation results show that the proposed controller can provide better transient stability, active power flow of the TCSC line, and voltage regulation performance than the ISEC with or without conventional TCSC controller and conventional power system stabilizer without any TCSC controller.

Application of Optimization Algorithms to Enhance the Transmission System Performance Using Thyristor Controlled Series Capacitor

Application of Optimization Algorithms to Enhance the Transmission System Performance Using Thyristor Controlled Series Capacitor

Satin Bowerbird optimization algorithm for the Application of Optimal power flow of power system with FACTS devices

The following research paper, addresses the issue of the optimal power flow ( OPF) of power system dealt by the proposal of adapting flexible ac transmission FACTS devices with Satin Bowerbird optimization (SBBOA) algorithm. The SBBOA is bio-inspired algorithm; it is carried out based totally on the principle of ‘female-attracted-by-male’ for breeding. The algorithm that is proposed is tested by usingIEEE-30 bus and IEEE-57 bus test systems with FACT devices of two different types. The following are the two types of FACT devices that are kept at fixed locations:
 FACT devices that are kept at fixed locations:
 Thyristor controlled series capacitor and
 Thyristor controlled phase shifter
 The objective of the present study aims at four different functions. They are:
 (a) Minimizing the cost of fuel
 (b) Minimizing active power loss during transmission
 (c) Reduction of emission and
 (d) Minimizing the combination of economic and environmental cost.
 The SBBOA give the finest simulation outcomes than lately proposed optimization algorithms given in the literature.

Faulted-Phase Identification in TCSC-Compensated Transmission Lines using Concordance Correlation Coefficient-Based Method

Fast fault detection in the Thyristor-controlled series capacitors “TCSC” compensated transmission line is the most challenging for many of the conventional fault detection methods. This paper proposes a new algorithm for fast fault identification in TCSC-compensated line based on concordance correlation of the current signals during the fault interval with corresponding current signals at the pre-fault interval. It is observed that the concordance correlation of the current signals at the present state with the same current signals at the previous state (just a few-cycle past) is very-strong during the health state and very weak when there is a fault state. Based on this and with the assistance of the cumulative approach, a fault detection index “” has been achieved. The proposed method has been tested through different fault circumstances including different compensation levels of TCSC device. Also, the proposed algorithm has been verified successfully with close in fault, high impedance fault, different sampling frequency, sudden load switching, load flow change and multi-machine system. The experimental results shown that the proposed method is good in terms of time response regardless of the compensation level, and therefore it is more efficient for series-compensated transmission lines protection.

Adaptive Mho Distance Protection for Interconnected Transmission Lines Compensated with Thyristor Controlled Series Capacitor

This paper proposes an adaptive dynamic Mho distance relay based on a phase comparator scheme for protecting interconnected transmission networks compensated with a Thyristor Controlled Series Capacitor (TCSC). The proposed relay uses an impedance index factor to initiate the fault detection subroutine. The RMS of the positive sequence current of the faulted loop and the TCSC terminal current are compared for TCSC zone identification. A phase comparator for ground and phase distance elements is proposed, relying on the positive sequence voltage as a polarized memory quantity, while the operating and polarizing quantities are developed using estimated TCSC impedance to mitigate its negative impact. The proposed scheme is easy in implementation and independent on synchronized data transfer, as minimum communication requirements are needed. To evaluate the performance of the proposed scheme, extensive simulation studies were carried out on an IEEE9 bus system compensated with TCSC for different firing angles covering four modes of TCSC operations, different fault types, and fault locations. In addition, an IEEE-39 bus network, as a large interconnected system, is tested for validation purposes. The achieved results designate the precision of the proposed scheme. Moreover, the results indicate its effectiveness for fault resistance tolerance, close-in three phase faults, and stable power swing phenomenon compared with conventional relays.

Mitigating inter-area oscillation of an interconnected power system considering time-varying delay and actuator saturation

A wide area damping controller (WADC) is designed in this paper to mitigate the frequency deviation of interconnected power system. The effect of time delay during wide area measurement system (WAMS) and saturation of the actuator is also considered in this work while designing the WADC. The effect of communication delay along with the saturation of a actuator can make the interconnected power system unstable. This paper focuses on finding a stabilization criterion of the power system connected with a WADC. The WADC is designed taking the effect of time-varying delay in the WAMS and saturation of the actuator into consideration. The saturation of the actuator is modelled with the help of dead zone type non-linearity. In this paper, a Lyapunov–Krasovskii functional is used to design a state feedback control law based on linear matrix inequality (LMI) taking time-varying delay and the actuator saturation into consideration. A thyristor controlled series capacitor (TCSC) is used as an actuator. A supplementary damping controller (SDC) is used as the WADC in this paper to provide sufficient damping. Simulation study on four machine 11 bus power system and New England 39 bus power system is performed to understand the performance of the designed controller. The results are also verified in real-time using OPAL-RT.

Power flow control of power systems based on a simple TCSC model

Thyristor-Controlled Series Capacitor (TCSC) is used to control the active power flow in transmission lines in the power system to specific values. This paper proposes a simple modeling of TCSC into Newton-Raphson load flow algorithm in order to reduce the complexity and enhance the reusability of the original load flow code. TCSC is represented by two injected loads at the sending and auxiliary buses. These loads are calculated based on the specified active power while the reactive power is calculated based on the systems. The reactive loads are updated during the iterative process until the convergence is achieved. TCSC parameters are calculated based on the voltages of connected buses and the specified active power. This model solves the problem associated with the selection of proper initial values of the TCSC control parameter. The proposed TCSC model is validated using the standard IEEE 14-bus, IEEE 30-bus and IEEE 118-bus test systems.

Optimal placement of facts devices to reduce power system losses using evolutionary algorithm

<p>The rapid and enormous growths of the power electronics industries have made the flexible AC transmission system (FACTS) devices efficient and viable for utility application to increase power system operation controllability as well as flexibility. This research work presents the application of an evolutionary algorithm namely differential evolution (DE) approach to optimize the location and size of three main types of FACTS devices in order to minimize the power system losses as well as improving the network voltage profile. The utilized system has been reactively loaded beginning from the base to 150% and the system performance is analyzed with and without FACTS devices in order to confirm its importance within the power system. Thyristor controlled series capacitor (TCSC), unified power flow controller (UPFC) and static var compensator (SVC) are used in this research work to monitor the active and reactive power of the carried out system. The adopted algorithm has been examined on IEEE 30-bus test system. The obtained research findings are given with appropriate discussion and considered as quite encouraging that will be valuable in electrical grid restructuring.</p>

Controller design for output constrained thyristor controlled series capacitor (TCSC) of time-delayed power system

Abstract Thyristor Controlled Series Capacitor (TCSC) is employed as actuator in an interconnected power system using Supplementary Damping Controller (SDC) to enhance the power transfer capabilities between areas as well as damp out the Inter-Area Low-Frequency (IALF) oscillations by varying the impedance of transmission lines. The time-varying delays in the feedback loop and asymmetric saturation limits at the output of TCSC may reduce the performance of the designed controller and lead to closed-loop instability if these are not considered in the process of controller design. Usually, a Minimum Absolute Saturation Bound technique (MASB) is used to convert asymmetric saturation limits into symmetric one. However, such consideration provides an apparent conservative and degrades the performance of the control system. To reduce the conservative in the control design process, a Normalized Saturation Bound (NSB) technique is used in this paper to convert asymmetric saturation limits of TCSC of time-delayed power system. The L-K functional and generalized sector conditions are utilized in the proposed controller design process to compensate the effect of time-varying delay and converted symmetric saturation limits. Sufficient conditions required for controller design are formulated in LMI form. 2-area 4-machine power model is used to verify the performance of the designed controller. From the simulation results, it is observed that the designed controller is giving superior performance in the present of time-varying delays and asymmetric saturation as compared to the designed controller using MASB technique.

Available Transfer Capability Enhancement by FACTS Devices Using Metaheuristic Evolutionary Particle Swarm Optimization (MEEPSO) Technique

Energy power flows are an important factor to be calculated and, thus, are needed to be enhanced in an electrical generation system. It is very necessary to optimally locate the Flexible Alternating Current Transmission Systems (FACTS) devices and improve the Available Transfer Capability (ATC) of the power transmission lines. It relieves the congestion of the system and increases the flow of power. This research study has been accomplished in two stages: optimization of location of FACTS device by the novel Sensitivity and Power loss-based Congestion Reduction (SPCR) method and the calculation of ATC using the proposed Metaheuristic Evolutionary Particle Swarm Optimization (MEEPSO) technique. The Thyristor Controlled Series Capacitor (TCSC) is used as a FACTS device to control the reactance of power transmission line. The effectiveness of the proposed methods is validated, utilizing the six bus as well as 30 bus system. The acquired outcomes are contrasted with conventional ACPTDF and DCPTDF procedures. These values are determined with the assistance of MATLAB version 2017 on the Intel Core i5 framework by taking two-sided exchanges and they are contrasted and values determined with the assistance of Power World Simulator (PWS) programming.

Power Loss Reduction and Voltage Profile Improvement Using Optimal Placement of FACTS Devices

The crucial role of an electric power system is to generate sufficient electricity to meet customer demands with an acceptable level of reliability in an economic manner. In recent years, Flexible AC Transmission Systems (FACTS) devices have been widely used to increase power system operation flexibility and controllability to meet this need. This paper presents an application of Differential Evolution (DE) to optimise the allocation of a Thyristor Controlled Series Capacitor (TCSC), a Static Var Compensator (SVC), and Unified Power Flow Controller (UPFC), as example FACTS devices. The objective of the research was to reduce power losses and improve the voltage profile in an IEEE 30-bus test system. The system performance was assessed with and without each FACTS device under different scenarios of load increase at up to 150% of the base case. The results obtained are encouraging in terms of reassessing electrical restructuring.

SSR Alleviation in SCIG-Based Wind Power Plants Using Resistive Bridge-Type FCL

Series-Compensated Transmission Lines (SCTLs) are widely used for connection of large scale wind power plants (WPPs) to the power system to transmit the active power generated from WPPs. However, it can lead to sub synchronous resonance (SSR) phenomena in WPPs connected with SCTLs. Also, capacitive compensation of transmission lines reduces the line impedance, which leads to increasing short circuit current level in WPPs. This study proposes the resistive bridge-type fault current limiter (RBFCL) for SSR mitigation and limiting short circuit current in WPPs connected with SCTLs. Also, its performance is compared with the static synchronous compensator (STATCOM) and thyristor controlled series capacitor (TCSC) to demonstrate the effectiveness of the RBFCL in terms of SSR mitigation. The WPP used in this paper is modelled based on an aggregated squirrel-cage induction generator (SCIG) derived by an aggregated wind turbine (WT). The PSCAD/EMTDC software and the IEEE first benchmark model are used for this study. Simulation results demonstrate that the RBFCL not only limits the short circuit current contribution of WPPs, but also effectively damps the SSR oscillations due to IGE as well as TI, when the WPP is subjected to a large disturbance.

A Novel Modified Lightning Attachment Procedure Optimization Technique for Optimal Allocation of the FACTS Devices in Power Systems

The Flexible AC Transmission Systems (FACTS) are the static power electronic devices that are installed and used in AC transmission networks to enhance the capability of transferring the power for providing the controllability and stability. However, the optimization of site and size of these devices is a crucial task due to their high capital cost and practical capabilities. In this paper, the optimal reactive power dispatch (ORPD) embedded with two effective controllers including the Static VAR Compensator (SVC) and Thyristor Control Series Capacitor (TCSC) is solved using a Modified Lightning Attachment Procedure Optimizer (MLAPO). The searching capability of basic LAPO is enhanced and the stagnation of basic LAPO is avoided by application of levy flight distribution and spiral orientation motion. The optimization for these devices is for reducing the power losses, voltage deviations, and the operating cost. MLAPO is examined and tested on modified IEEE30 and IEEE57 bus-standards considering SVC and TCSC. The effectiveness of MLAPO is further analyzed and compared with the outcomes of the well-known optimization techniques namely LAPO, PSO, ALO, EO, MPA, WOA and SCA with and without FACTS devices.

Comparative Analysis on Optimal Placement of TCSC under Single Line Contingency by Using PSO and GA

In the network contingencies, the branch overloading and voltage violation are the most serious conditions and may lead to security problems. The application of Thyristor Controlled Series Capacitor (TCSC) can provide the required apparent reactance smoothly and rapidly and can reduce network contingency problems. This paper focuses an application of Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) to find out the optimal locations of TCSC devices under single contingency to reduce the voltage drops at system buses and line flow improvement on transmission lines. The suitability of the proposed technique is examined on Myanmar Electric Power System. The optimized location provided by each method is applied to single line contingency condition and the responses are observed. According to the simulation results, PSO method can provide the better the stability performance under single line contingency.

Optimum Design of Damping Controllers Using Modified Sperm Swarm Optimization

This paper is proposed a modified sperm swarm optimization algorithm (MSSO) for numerical function optimization and optimal design of damping controller in power system. To provide a fine balance between the explorative and exploitative behavior, MSSO utilizes a chaotic velocity damping factor. In addition, the proposed method considers a reasonable velocity limitation to avoid explosion and divergence of the sperm movement. The proposed algorithm is benchmarked with a set of test functions and the results are compared with the standard sperm swarm optimization (SSO) and some other robust metaheuristic from the literature. To demonstrate the feasibility and effectiveness of the proposed method in power systems, power system stabilizers (PSS) and thyristor-controlled series capacitor (TCSC) controllers are designed for a 5-area 16-machine system. The performance of the suggested controllers on a multi-machine power system under various operating situation is evaluated using a nonlinear time-domain simulation. As results demonstrate, the MSSO is superior and could generates better optimal solutions in compared with SSO and other competitive algorithms. The numerical results reveal that, for damping oscillation problem the modified algorithm (MSSO) converges faster than the other methods.