Thyristor Controlled Series Capacitor Research Articles

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.

Harmonic analysis of thyristor controlled series capacitor in polluted Algerian network

Harmonic analysis of thyristor controlled series capacitor in polluted Algerian network

Coordinated SMES and TCSC Damping Controller for Load Frequency Control of Multi Area Power System with Diverse Sources

This paper investigates the load frequency analysis (LFC) of two area interconnected realistic power system with multi-fuel generating units. Each area consists of thermal, hydro and gas power generating plants. A new evolutionary algorithm is proposed, named Hybrid artificial electric field (HAEFA) optimization algorithm and integral square error (ISE) performance index is utilized to find classical PI/PID controller gains. Later, total analysis is carried out in presence of PID an account of its superiority functioning rather than PI. Moreover, the efficacy of the presented algorithm is deliberated by testing on two area conventional power system model of thermal unit with structure of non-reheat turbines and also on sphere benchmark function. As the load variation is dynamic in nature, mitigating the area frequency fluctuations and tie-line power variations could not been fulfilled by primary regulator and secondary controller. Effective governing needs additional devices. Therefore, superconducting magnetic energy storage (SMES) devices are incorporated in both areas in addition to Thyristor controlled series capacitor (TCSC) is connected in tie-line. Results, shows the system performance has been significantly improved with SMES and TCSC in the presence of HAEFA based PID controller. The potency of the HAEFA algorithm is compared with other optimizations covered in literature.

A novel approach for optimal allocation of series FACTS device for transmission line congestion management

AbstractThe reformed electricity market structure has forced the transmission network to operate near its operational limits. Due to competition in electricity market and with increasing demand, the probability of occurrence of congestion in transmission network has also increased. This resulted in insecure operation of power system and inefficient operation of the electricity market. The main aim of this article is to achieve efficient management of congestion in terms of minimum cost of electricity. This is accomplished by optimally allocating thyristor‐controlled series capacitor (TCSC) in the system. Since flexible alternating current transmission system (FATCS) devices involve heavy installation cost, its proper allocation plays a vital role in achieving the electricity market economics. Therefore, in this article, a new sensitivity index called line flow sensitivity factor is proposed to find the optimal location of TCSC while its control parameter setting is optimally obtained with particle swarm optimization algorithm. The obtained results are validated through implementation of TCSC based on its minimum installation cost. Further, two different penalty factors for violation of system constraints are also introduced in the problem formulation to effectively consider the competitive nature of the electricity market. The proposed method is tested on IEEE 30‐bus system, IEEE 118‐bus system, and 33‐bus Indian network and the results are found to be encouraging. The performance of the optimization algorithm on different systems is also analyzed in this article.

Comparison of (SVC/TCSC) - (STATCOM/SSSC) compensators and UPFC controller in network coupled to wind farm using Jacobian matrix in Newton-Raphson algorithm

In recent years, the fast progress in the field and the application of the electronic system transmission plays an important role to make the system more reliable, controllable and efficient. It opened new opportunities for the application of the FACTS devices. The Flexible Alternating Current Transmissions System technology (FACTS) is used to have an optimal continuous power flow and open up new opportunities for controlling the electric system network. The UPFC (Unified Power Flow Controller) is one of the most versatile and complex power electric devices in the FACTS family. UPFC can control the active and the reactive power flow, a local bus voltage, it can also result a problem due to harmonics. In that regard, this paper presents a case study in which the PSAT software was implemented to comparing and analyzing the performance of the hybrid compensators namely (SVC/TCSC), (STATCOM/SSSC) and the UPFC in network coupled to wind farm. The Static Var Compensator (SVC) is a first shunt generation FACTS controller. TCSC (thyristor Controlled Series Capacitor) is consisted as a series compensating capacitor shunted by a thyristor controlled reactor. We can see that the UPFC controller has an effective power flow control, less setting time and less overshoot. The UPFC obtained a well known reputation for high controllability in power systems. The multilevel UPFC can be operated in STATCOM (Static Synchronous Compensator), in SSSC (Static Synchronous Series Compensator) and exactly in the UPFC mode. The results using Jacobian matrix in Newton-Raphson algorithm of UPFC are more significant compared to the hybrid (SVC/TCSC) and the (STATCOM/SSSC) controllers.

Harmonic analysis of thyristor controlled series capacitor in polluted Algerian network

This paper presents the study of the impact of harmonic distortion generated by the thyristors controlled series capacitor (TCSC) in Algerian electric power system. By applying Fourier transform of terminal voltage and switching function, the TCSC model is used as a harmonic admittance matrix, in the frequency domain, and then integrated into a balanced harmonic load flow algorithm based on the Newton-Raphson method. The study has been carried out with the equivalent Algerian power system 114 bus. The total harmonics and RMS voltages are evaluated under different operating regions of the TCSC.

Impact of TCSC on Directionality of Traveling Waves to Locate Faults in Transmission Lines

The use of devices based on power electronics has been widely spread to improve the transmission lines performance. However, the inclusion of these compensators, named Flexible AC Transmission Systems, produces adverse effects on conventional protection schemes. For instance, it modifies the apparent impedance of transmission lines. This condition produces malfunction in conventional distance protection. This paper presents an algorithm protection for power transmission lines, compensated with a Thyristor-Controlled Series Capacitor. The proposed algorithm is capable of discriminating the directionality of traveling waves as well as detecting and locating eleven types of faults. The impact of the Thyristor-Controlled Series Capacitor device in the directionality of traveling waves is analyzed and separated for developing the protection. The obtained results show that the directionality of the algorithm is not affected by the presence of Thyristor-Controlled Series Capacitor. In order to validate the algorithm, several study cases are considered. The error calculating distance to fault is smaller than 1.25%

A New Approach for Protecting TCSC Compensated Transmission Lines Connected to DFIG-Based Wind Farm

Thyristor-controlled series capacitor (TCSC) compensated transmission lines (TLs) are increasingly used in recent years for transmission of bulk power generated by doubly fed induction generator (DFIG) based large scale wind farms. However, the typical fault characteristics of DFIG and TCSC affect the performance of conventional distance relays. To solve the problem, in this article, a new relaying algorithm is proposed that utilizes sign of the half-cycle superimposed positive-sequence current for fault detection, empirical mode decomposition assisted random forest classifier for fault classification and modified impedance approach for fault location estimation. The performance of the proposed relaying algorithm is evaluated on various fault and nonfault cases generated on a test power system using MATLAB/Simulink and OPAL-RT (OP4510) manufactured real-time digital simulator environment. Also, compared with few existing approaches. The demonstrated results justify the merits of the proposed relaying algorithm for protecting the TCSC compensated TL connected with DFIG-based wind farm.

A probabilistic multi-objective approach for FACTS devices allocation with different levels of wind penetration under uncertainties and load correlation

This study presents a probabilistic multi-objective optimization approach to obtain the optimal locations and sizes of static var compensator (SVC) and thyristor-controlled series capacitor (TCSC) in a power transmission network with large level of wind generation. In this study, the uncertainties of the wind power generation and correlated load demand are considered. The uncertainties are modeled in this work using the points estimation method (PEM). The optimization problem is solved using the Multi-objective particle swarm optimization (MOPSO) algorithm to find the best position and rating of the flexible AC transmission system (FACTS) devices. The objective of the problem is to maximize the system loadability while minimizing the power losses and FACTS devices installation cost. Additionally, a technique based on fuzzy decision-making approach is employed to extract one of the Pareto optimal solutions as the best compromise one. The proposed approach is applied on the modified IEEE 30-bus system. The numerical results evince the effectiveness of the proposed approach and shows the economic benefits that can be achieved when considering the FACTS controller.

An improved setting method of the distance protective IEDs for series-compensated transmission lines based on a case study approach

An improved setting method of the conventional distance protective IEDs for the series compensated transmission lines based on the results of the comprehensive studies regarding the impact of a thyristor-controlled series capacitor (TCSC) is proposed in this paper. The proposed method considers the equivalent impedance of TCSC to calculate the distance protective IED setting values which can prevent the mal-operation. To verify and analyze the performance of the proposed method, the HILS(Hardware-In-the-Loop System) was constructed using RTDS and an IED. The IEC 61850-based dynamic characteristic tests were performed with this HILS.

Performance analysis of distributed power flow controller with ultra-capacitor for regulating the frequency deviations in restructured power system

Abstract This paper presents a novel approach for automatic generation control (AGC) of two-area deregulated system with unequal sources for sustaining the frequency and tie-line power at perturbations. The combination of ultra-capacitor (UC) and various FACTS controllers such as Thyristor-controlled series capacitor (TCSC), Static synchronous series compensator (SSSC), Unified power flow controller (UPFC), and Distributed power flow controller (DPFC) have been investigated in AGC of interconnected system with thermal-wind and hydro-diesel generating units. An innovative metaheuristic method called bat algorithm (BA) is used to ascertain the optimal gain parameters of the two degree of freedom (2DOF) controllers using an integral squared error (ISE) criteria. Furthermore, the productive assessment of the bat tuned 2DOF controllers are also compared with teaching learning-based optimization (TLBO) and cuckoo search (CS) methods optimized 2DOF in distinct contract scenarios of the suggested restructured system. The effect of the coordinated performance of UC and DPFC has been mitigated the oscillatory response of the AGC system at various operating circumstances. The investigations disclose that the bat optimized 2DOF-PID yield the productive outcomes with coordination of DPFC and UC in all contract transactions of the restructured system.

A Fault Detection Technique During Power Swing in a TCSC-Compensated Line Using Teager Kaiser Energy Operator

Thyristor controlled series capacitor (TCSC) is placed in transmission line to enhance its power transfer capability. However, several relaying methods experience the challenges of voltage and current inversion, nonlinear behavior of MOV and sub-synchronous oscillations in the presence of TCSC. Furthermore, power swing causes unwanted trip and severely affects the protection schemes due to the modulation of relaying signals for a TCSC-compensated line. Even, fault detection is not possible due to power swing blocking (PSB) element which blocks distance relay when impedance trajectory lies inside the relay trip zone. To overcome the problem associated with TCSC and PSB operation within the duration of power swing, a fault identification technique, based on multiplication of Teager Kaiser Energy Operators (TKEOs) of negative sequence (NS) current and voltage phasors, is proposed. It has been tested in numerous fault cases in various system conditions and compared with the existing schemes. The proposed technique can be implemented with a threshold which is a major advantage of it. Availability of local end relay voltage and current data make the scheme reliable and fast. To validate the proposed scheme, a WSCC 9-bus system with consideration of 400 kV, 50 Hz has been simulated and tested using EMTDC/PSCAD software.

Sub-synchronous Resonance Constrained OPF Using Reconciled Pack Dominance Based Grey Wolf Optimisation

In this paper, the Sub-synchronous Resonance Constrained Optimal Power Flow (SSRCOPF) problem is articulated, for stable and economic operation of series compensated power system. Further, Reconciled Pack Dominance based Grey Wolf Optimisation (RPD-GWO) is proposed to solve SSRCOPF problem. Due to the colossal increase in demand, transmission lines are stressed by overloading. To alleviate this stress, often series compensation by Thyristor Controlled Series Capacitor (TCSC) is used. However, due to unintended operation of TCSC there is a possibility of Sub-synchronous Resonance (SSR). Hence, SSR constraint is infused into Optimal Power Flow (OPF) and termed as SSRCOPF. The proposed SSRCOPF ensures optimal system operation, while circumventing the entrapment into SSR condition. To solve the SSRCOPF problem the proposed RPD-GWO algorithm is employed and analysed with Particle Swarm Optimisation (PSO). The comparative analysis of proposed RPD-GWO algorithm reveals its swiftness in convergence.

Fault detection during power swing in thyristor-controlled series capacitor-compensated transmission lines

Fault detection during power swing in compensated transmission lines by Thyristor Controlled Series Capacitors (TCSCs) is a challenging problem and conventional detection methods might not be accurate. In this paper, a high speed fault detection approach based on Mathematical Morphology is proposed. The proposed method uses voltage and current signals for fault and swing detections, respectively. The performance of the proposed method is evaluated using two simulation case studies simulated in PSCAD/EMTDC: (i) a single machine infinite bus network and (ii) IEEE standard 9 bus three machine network. It is shown that the proposed approach is not sensitive to nonlinear behavior of TCSCs and it is capable of detecting all types of faults, including three-phase ones, during power swing accurately. In addition, due to low computational complexity, the proposed method provides significantly high detection speed.

Enhancement of ATC of micro grid by optimal placement of TCSC

Presently micro grid network are force to operate close to their stability limit due to exponential growth of power demand. Maintaining transmission line parameters within permissible limits during transient is a challenging task. The principal parameters for assessment of instability during transient are Critical Clearing Time (CCT) and Critical Clearing Angle (CCA). The highly developed semiconductor based power thyristor device, enable the power engineer with most versatile Flexible AC transmission System (FACTS) controllers. Thyristor controlled series capacitor (TCSC) provide great strategy for controlling parameter during transient and enhancing stability and Available Transfer Capability (ATC) of transmission lines. In this paper IEEE 14 bus system is considered as the test system. A three phase fault is simulated and the voltages for pre, during and post fault condition are analyzed. The CCA and CCT are calculated by solving swing equation using point by point method. The delta-time curve at different fault clearing time both with and without connecting TCSC are plotted to study behaviour of delta variation and hence to evaluate transient stability.

Voltage Sag Compensation of Transmission Line System by using Thyristor Controlled Series Capacitor

Voltage Sag Compensation of Transmission Line System by using Thyristor Controlled Series Capacitor

A pilot protection algorithm for TCSC compensated transmission line with accurate fault location capability

This paper introduces a communication-aided scheme to enhance the fault detection, and fault location calculation for a thyristor-controlled series capacitor (TCSC) compensated transmission lines. In the proposed method only the current data at the remote-end should be synchronously sent to the local-end. Since the remote-end voltage data do not use in local-end, compared with the conventional pilot impedance-based protection schemes, the proposed method significantly reduces the requirement of data transmission bandwidth. The proposed algorithm is independent of fault resistance, power flow direction, and pre-fault condition. In the proposed method the TCSC parameters are not utilized in the derived fault location formula and as a result, the performance of the proposed method is not impacted due to variations in TCSC parameters. Several major factors are taken to investigate the accuracy of the proposed method, including measurement errors and power swing conditions. The simulation results prove the high accuracy and acceleration of the proposed scheme during all fault cases.

FACTS Devices Loss Consideration in Placement Approach for Available Transfer Capability Enhancement

This paper incorporates Flexible AC Transmission System (FACTS) device loss with the general loss sensitivity equation for the determination of optimum location for its placement in deregulated power networks, with objectives of Available Transfer Capability (ATC) enhancement, bus voltage improvement and loss reduction. A detailed mathematical model in terms of circuit system parameters is presented based on FACTS loss amalgamation approach. Thyristor Controlled Series Capacitor (TCSC) FACTS device is considered for simulation and analysis because of its capability to control active power among other parameters. The TCSC location is established based on analysis of sensitivity factors obtained from partial derivatives of the resultant loss equations (including FACTS) with respect to control parameters. ATC values are obtained using ACPRDF method and with TCSC in place, these values are enhanced for different bilateral and multilateral power transactions. IEEE 5 Bus system is used for the demonstration of the effectiveness of this approach. Placement with this method resulted into ATC enhancement of more than 60% well above the values obtained when TCSC was placed with thermal limit method. In addition, a substantial bus voltage improvement of up to 3% deviation minimization as well as up to 10% active power loss reduction was recorded with this placement.

RETRACTED ARTICLE: Estimation of loadability limit with N-1 and N-2 outages using evolutionary computation techniques

Voltage stability primarily depends on the voltage magnitude, phase angle, real and reactive power constraint of the electric power system. Even during emergencies like contingency (outages), the stability of the electric power structure will be enhanced by improving the Loadability Limit (LL) of the transmission sector. Flexibility in the real and reactive power flow in the transmission system is achieved by the Flexible AC Transmission System (FACTS) devices. These devices can be placed anywhere in the transmission sector. To get effective control over the power flow through the transmission lines and to achieve the maximum loadability with the minimal installation cost, optimal choice and placement of FACTS devices are essential. In this manuscript, efforts had been taken to analyze the LL with outages for hybrid electric power structures. The proposed method is simulated and tested with the hybrid version of standard IEEE 30 bus system. Three types of FACTS devices like Thyristor Controlled Series Capacitor (TCSC), Static VAr Compensator (SVC) and Unified Power Flow Controller (UPFC) are efficiently selected and placed in the transmission lines. For the optimal positioning and placement of these devices, the Contingency Severity Index (CSI) and Fast Voltage Stability Index (FVSI) have been used. Differential Evolution (DE) and Modified Differential Evolution (MDE) algorithms are applied to optimize the obtained results. DE is an evolutionary search based soft computing algorithm popularly handed to resolve multifarious problems. MDE is the enhanced version of DE that embraces a prior knowledge about the solution space at every stage of the search. The main focus of this work is (i) to identify the weak branches and buses in the system using CSI and FVSI. (ii) to optimize the number, location and settings of FACTS devices using various soft computing techniques like DE and MDE. (iii) to evaluate ML of a transmission system with FACTS devices under normal and contingency conditions using DE and MDE. (iv) to calculate the cost required for the installation of FACTS devices. (v) to enhance ML of pool and hybrid model of deregulated electric power market with contingency using the optimal number, rating and positioning of FACTS devices.

Fault Detection During Power Swing in a TCSC-Compensated Transmission Line Based on Clark’s Transform and Teager–Kaiser Energy Operator

Fault detection during power swing is a critical task as relays remain blocked leaving the system unprotected. Power swing in general is symmetrical, but asymmetrical power swing occurs during single-phase auto-reclosing operation. Both the power swings severely affect the fault detection schemes. Fault detection gets further complicated when transmission lines are compensated by thyristor-controlled series capacitor (TCSC). To protect the power network during power swing blocker operation under aforementioned circumstances, a sample-based technique using Clark’s transform and Teager–Kaiser energy operator is proposed. This technique is capable of detecting faults during symmetrical and asymmetrical power swings in transmission line with or without TCSC compensation. The proposed method has been validated by thorough mathematical analysis and simulation studies for various cases of fault during power swing.