Incorporating TCSC into the voltage stability constrained OPF formulation

This paper investigates the effect of thyristor controlled series capacitor (TCSC) and static VAr compensator (SVC) on power system load curtailments. The research on TCSC and SVC is abundant, but most of them are on power system stability improvement. This paper proposes a new use of TCSC and SVC to reduce load curtailments. An algorithm of optimal power flow (OPF) to reduce the load curtailment for installing TCSC/SVC in the system is proposed in this paper. Several examples are used to demonstrate the effect on load curtailment. The test results show that the effect of TCSC/SVC is significant. This paper also suggests some potential future research.

This paper deals with optimal location of Flexible AC Transmission system (FACTS) device like Thyristor Controlled Series Capacitor (TCSC) by performing Optimal Power Flow (OPF) and sensitivity based methods. The OPF is performed on IEEE-14 bus system by minimizing the total system cost with an iterative procedure. As the number of buses increases the evaluation of the optimal location of TCSC becomes difficult because the complexity of the method based on OPF increases. Whereas the sensitivity based method may be easy to use even for the complex system. The above methods are performed in MATLAB and the required optimization is done in GAMS.

In this paper, a mathematical model is developed for the steady state behavior of thyristor controlled series capacitor (TCSC). The TCSC mathematical model is developed by using firing angles of the thyristors as the modeling input. Based on the model developed and the effective TCSC reactance model presented in the literature, the steady state behavior of TCSC under varying capacitance and inductance values is investigated. The results obtained showed that a multiple-TCSC resonance point occurred when inappropriate values for the TCSC parameters are chosen. As a result, the steady state behavior of TCSC as well as its operating performance is negatively influenced. MATLAB application software is used for this study. In conclusion, this study shows that to enhance power flow flexibly on the transmission line with the use of TCSC, it is important to design appropriate values for the TCSC capacitance and inductance.

In this study, an efficient and reliable algorithm known as Jaya Algorithm-enabled Flower Pollination Algorithm (JA-FPA) is introduced for enhancing the Optimal Power Flow (OPF) and system security by a multi objective model. The multi-objective model is first derived based on entropy of individual objectives such as the Voltage Stability Index (VSI), Power Loss Index (PLI), Line Collapse Proximity Indexes (LCPI), severity and TCSC cost. Multi- objectives are achieved by optimizing the location as well as size of Flexible Alternating Current Transmission System (FACTS) devices in the test bus system. Consequently, the most popular and ubiquitous component of the FACTS equipment category, the Thyristor Controlled Series Capacitor (TCSC), is utilized in this study. The best solution with optimal sizing and allocation of TCSC devices for achieving the aforesaid objectives is chosen from the JA-FPA optimized outputs. The proposed model is performed on two benchmark test bus systems. The adopted model is distinguished with conventional models, and the results are obtained to analyze its effectiveness. In particular, the computational time of proposed model is is 1.74%, 2.52%, 1.13%, 0.63%, 50.15%, 2.36%, 3.83%, 6.00%, 2.79%, and 7.57% superior to existing GWO, WOA, DA, FPA, JA, PSO + GSA, PSO, Henry gas, GA, and TLBO approaches.

This paper investigates potential of modified differential evolution (MDE) algorithm, to find solution for optimal power flow (OPF) problem of power system. The performance of the proposed MDE algorithm is experienced on the modified IEEE-30 bus test systems integrating flexible ac transmission systems (FACTS) devices, that is, thyristor controlled phase shifter (TCPS) and thyristor controlled series capacitor (TCSC) at preset locations. The OPF problem of the present work is formulated with five different objective functions viz. (a) fuel cost (with valve point effect) minimization, (b) power transmission losses minimization, (c) emission reduction (d) fuel cost (without valve point effect) minimization and (e) minimization of combined economic and environmental cost. The proposed implementation exploits MDE, resulting in a much shorter execution time while retaining the best possible solution of OPF problem.

TCSC with auxiliary controls based voltage and reactive power controls on grid power system

The paper reviews the formulation of optimal power flow (OPF) and its role in dispatch. It then outlines possible uses of OPF market structures and describe the major drawbacks. The use of OPF for market players with a portfolio of generating units, however, is an appropriate and useful application of OPF in competitive markets. The OPF in such cases is a useful tool to determine the most cost-effective approach to discharge certain contracted market obligations since there is a centrally controlled single ownership situation. The application of OPF in such cases is reviewed. The paper emphasizes the limitations and capabilities of applying the OPF tool in market structures.

In this paper we present a model for installing thyristor controlled series capacitors (TCSC) to reduce the cost of power generation while maintaining the N-1 secure network. The proposed mathematical program considers all contingencies in one problem. The proposed TCSC location-allocation problem is a non-linear non-convex mathematical program. We use the general linearization technique to convexify the polynomial constraints and consider the investment cost of TCSCs as well as the expected value of loss load (EVOLL) under all states of the system. Results show that the power flow control capability of TCSC provides a better operation of a test network.

Flexible AC Transmission Systems (FACTS) play a vital role in enhancing the stability, efficiency, and reliability of modern power systems. With the increasing complexity of power grids due to the integration of renewable energy sources, effective control of power flow, voltage regulation, and stability improvement are critical challenges. FACTS devices, such as Static Synchronous Compensator (STATCOM), Unified Power Flow Controller (UPFC), and Thyristor- Controlled Series Capacitor (TCSC), offer advanced solutions to mitigate these challenges by providing dynamic voltage control, reactive power compensation, and congestion management. This paper presents a comprehensive analysis of various FACTS devices, focusing on their control strategies, applications, and impact on improving power system performance. Simulation results demonstrate the effectiveness of FACTS devices in maintaining voltage stability, optimizing power flow, and minimizing transmission losses, ultimately contributing to a more efficient and resilient power grid.

Coordinated tuning of PSS and TCSC to improve Hopf Bifurcation margin in multimachine power system by a modified Bacteria Foraging Algorithm

—The optimal power flow problem seeks to find an optimal profile of active and reactive power generations along with voltage magnitudes in such a manner as to minimize the total operating costs of a power system while satisfying network security constraints. This article presents a firefly algorithm to solve the optimal power flow problem incorporating a thyristor-controlled series capacitor. A thyristor-controlled series capacitor is considered to find the optimal location in transmission lines to enhance the power transfer capability of the transmission line. To assess the effectiveness of the proposed algorithm, it was tested on a 5-bus test system, an IEEE 14-bus system, and a modified IEEE 30-bus system, and it was compared with the genetic algorithm and differential evolution with and without a thyristor-controlled series capacitor. It has also been observed that the proposed algorithm can be applied to larger systems and does not suffer with computational difficulties. The results show that the firefly algorithm produces better results than others and has fast computing time for solving the optimal power flow problem with a thyristor-controlled series capacitor.

In this paper, a hybrid tabu search and simulated annealing (TS/SA) approach is proposed to minimize the generator fuel cost in optimal power flow (OPF) control with multi-type of flexible AC transmission systems (FACTS) devices. The problem is decomposed into the optimal setting of FACTS parameters subproblem that is searched by the hybrid TS/SA approach and the OPF with fixed FACTS parameters subproblem that is solved by the quadratic programming (QP). Four types of FACTS devices are used: thyristor-controlled series capacitor (TCSC), thyristor-controlled phase shifter (TCPS), unified power flow controller (UPFC), and static VAr compensator (SVC). Test results on the modified IEEE 30 bus system with multi-type of FACTS devices indicate that the proposed hybrid TS/SA approach can obtain better solutions and require less CPU times than genetic algorithm, SA, or TS alone. Using multi-type of FACTS devices results in less total generator fuel cost than using individual FACTS device.

Thyristor-controlled series compensation (TCSC) systems and thyristor switched series compensation (TSSC) systems are power electronic systems developed in the late 1980s and early 1990s in response to the anticipated need for better utilization of existing high voltage overhead transmission lines because of the difficulties in getting approval for building new lines. The actual experience has been that TCSC systems are primarily being applied in areas with high growth rates where there is a need for long, high voltage ac transmission lines. However, even in areas with existing high power lines imbedded in the ac power system, the load carrying capacity of the lines can be improved by using fixed or switched series capacitor compensation systems. The inherent risks associated with increased loading of existing lines is that if the power system were to be subjected to severe disturbances, there might be a wide spread blackout. TCSC systems represent a tool to manage disturbances and to avoid blackouts by quickly rerouting the power flows from the high stressed lines to lines with the ability to carry higher loads and thereby avoiding blackouts. TCSC systems have been applied to enable construction of long ac lines, which would be unstable if the TCSC systems were not installed. That is, TCSC systems have been proven to be a powerful tool to enhance the stability of the ac systems and even to provide damping of subsynchronous oscillations where the use of fixed series capacitor (FSC) installation could have caused subsynchronous resonance endangering the reliability of large steam turbine generators.The design requirements for the TCSC FACTS controller are discussed in this chapter. The fundamental operating principles of TCSC systems, the key TCSC design aspects, standards, and other documents, which would be useful to have by those who procure, maintain, or operate a TCSC system are also discussed in this chapter.

Design and Development of Self Tuning Controller for TCSC to Damp Inter Harmonic Oscillation

In this paper, hybrid tabu search and simulated annealing (TSSA) with search space managing methods are proposed to determine the optimal number and allocation of FACTS controllers to enhance power transfer capability of power transactions between generators and loads in power systems. Particular optimal allocation includes optimal locations and parameter settings. Two types of FACTS controllers including thyristor-controlled series capacitor (TCSC) and static var compensator (SVC) are used individually. The objective function is formulated as maximizing total transfer capability (TTC) and minimizing power losses. Power transfer capability determinations are calculated based on the optimal power flow (OPF) technique. Split and non-split search space managing methods are used to improve the solution searching capability. Test results on IEEE 118-bus system and the practical Electricity Generating Authority of Thailand (EGAT) 58-bus system show that the proposed hybrid TSSA with optimal number of FACTS criteria and the split search space managing method give higher TTC and less number of FACTS controllers than those from evolutionary programming (EP) and non-split search space method.