Static Synchronous Series Compensator Controller Research Articles

Analysis of the combined effects of SVC and SSSC controllers to improve power system stability

The primary challenge facing the electricity transmission system in the aftermath of the disruption is reestablishing stability. Through adjustment of the transmission parameters, the Flexible AC Transmission System (FACTS) devices have the potential to bring the system back into stable operation. It has been shown that using many FACTS devices together is more effective than using any one device alone. In this paper, the concept of coordination control between a Static Var Compensator (SVC) and a Static Synchronous Series Compensator (SSSC) is suggested in order to make the system more stable. The equivalent impedance of the line may be reduced by using the SSSC, which will also result in improved active power transfer capabilities for the line. A static var compensator, often known as an SVC, is used for shunt compensation in order to keep the bus voltage magnitude stable. When compared to the use of a single device, the use of SVC and SSSC coordinated control results in a much quicker arrival to the steady state response of the system. Both of these devices are controlled by using the same signal input tracking. It has also been seen that the system has resumed its previous synchronized state.

Rotor angle stability improvement by coordinated control of SVC and SSSC controllers

After a disruption in the power transmission system, the most crucial challenge is restoring the system’s stability. The FACTS devices can manipulate the transmission parameters to bring the system back into stable operation. This paper discusses the operational concepts and applications of FACTS in power systems such as the Static Var Compensator (SVC) and the Static Synchronous Series Compensator (SSSC). When combined with the other devices, the effectiveness of each individual device is increased. This paper proposes the coordinated control of SVC and SSSC to improve system stability. The SSSC can be utilized to lower the line’s equivalent impedance and improve its operational power transfer capabilities. The SVC is used for shunt compensation to maintain bus voltage magnitude. Furthermore, the steady-state response of the system is faster when SVC and SSSC coordinated control is employed compared to a single device. The resultant variable signal of the SSSC controller is tracked to control the SVC controller. A significant fault is introduced in the tie-line of the inter-area system to analyse and validate the proposed coordinated control. MATLAB/Simulation results are presented for the proposed approach, and also a real-time simulator is used to validate the simulation results.

Transient stability increase of multi-machine power system by using SSSC and DFIG control with TEF technique and super twisting differentiator

This paper suggests a nonlinear controller of a Static Synchronous Series Compensator (SSSC) and a doubly-fed induction generator (DFIG) for transient stability enhancement by transient energy function (TEF) technique and super-twisting differentiator in the multi-machine power system. Initially, the TEF approach is employed to damping control and stability enhancement in a multi-machine power system including an SSSC, DFIG, and synchronous generator (SG). Then, the signals of time-derivative in the controller with a super-twisting differentiator are estimated. The significance and novelty of this work are the employs of the TEF method obtained for the multi-machine power system containing DFIG and SG. Another novelty is the use of the DFIG and SSSC simultaneous control whose uncertain parameters are estimated with a super-twisting differentiator. The feature of the nonlinear control approach is robust versus modifications in the topology of the system. Simulation is performed on the IEEE 9-bus system to appraise the operation of the nonlinear controller approach compared to back-stepping and sliding mode control. The simulation results demonstrate that the nonlinear controller approach satisfactorily reduces the first swing of oscillations.

Optimal design of SSSC and crowbar parameters for performance enhancement of Egyptian Zafrana wind farm

Zafarana Wind Park is considered the largest wind farm in Middle East. By the year 2022, Zafarana wind farm will inject 545 MW to Egypt national electric network (ENEN). This wind farm has been connecting to ENEN in stages (eight stages) from ten years ago. Each stage represents a project of wind farm. Hence, the impact of the emergency condition of ENEN on the performance of the installed stage of Zafarana Wind Park should be studied. Moreover, determining the possible method to reduce the side effects of the emergency condition of ENEN on the installed stage of Zafarana Wind Park becomes an important issue. In this paper, a combination between Static Synchronous Series Compensator (SSSC) and crowbar (Cro-SSSC) is used to enhance the performance of the one installed stage of Zafarana Wind Park. The studied stage of Zafarana Wind Park is Zafarana Z1 wind farm (Z1). Zafarana Z1 wind farm represents that first stage of Zafarana Wind Park that was connected to ENEN. Hence, the paper takes Zafarana Z1 wind farm as the studied case to examine the impact of Cro-SSSC. The crowbar is used to protect the power components of the SSSC from the high current during grid fault condition. Also, in this paper multi-objective lightning attachment procedure optimization algorithm (LAPO) and the sine cosine algorithm (SCA) are used to evaluate and tune the control gains of SSSC and the value of crowbar's resistance. This step is important in order to determine the values of the control's gains of SSSC and the value of crowbar resistance which suit the studied system (one installed stage of Zafarana Wind Park). The sliding mode control (SMC) is used as an example of nonlinear control of SSSC. Also, a hybrid of LAPO and SMC is used to improve the performance of Zafarana Z1 during faults. The results of LAPO, SCA and SMC are compared during three-phase fault and single line to ground fault applied to the studied system.

Improving Power Flow Using Static Synchronous Series Compensator

Due to adaptation of new lifestyles, energy demand in the power sector rapidly increased day-by-day. To overcome this energy gap Flexible Alternating Current Transmission System (FACTS) controllers are the most reliable option irrespective to upgradation of power networks. Static Synchronous Series Compensator (SSSC) is one of a series family, second generation FACTS controller used in power networks to enhance power transfer capacity. In this paper, a new SSSC based indirect controller is proposed for a 500kV grid station. In SSSC, multilevel, 48pulse, Neutral Point Clamped (NPC) based Voltage Source Converter (VSC) is implemented that injects a controllable compensating voltage in series with transmission line. Almost 20% enhanced power flow can be achieved by using proposed cost-effective SSSC controller. The aim of this paper is to find drawbacks associated with previously designed controller and design a new controller for power flow improvement. Also compare their results for power flow in 500kV grid station using MATLAB/Simulink 2017 (a). . . . . .

Scattering Transformation Based Wide-Area Damping Controller of SSSC Considering Communication Latency

This paper presents a new design of a scattering transformation-based wide-area damping controller for static synchronous series compensator (SSSC) to enhance power system stability in the presence of communication latency. The proposed control approach is comprised of a classical structure in addition to two scattering transformation ports. These ports are inserted between the power system and the wide-area damping controller (WADC) to regulate the signal exchange. Since the WADC is a centralized controller, the time delay imperfections are considered in the design stage. The proposed controller design is formulated as an optimization problem where the controller parameters are optimized using the particle swarm optimization (PSO) algorithm. The proposed controller improves the system damping performance due to the achieved time delay compensation. The proposed controller's effectiveness is demonstrated by implementing the controller in several case studies under different disturbance scenarios. The proposed controller performance is benchmarked with the classical WADC based on the lead-lag structure. The results confirm the robustness of the proposed WADC against time delay uncertainty. The proposed controller's efficacy is confirmed to reduce the time delay, resulting in better power system stability.

Optimal Siting and Sizing of SSSC Using Modified Salp Swarm Algorithm Considering Optimal Reactive Power Dispatch Problem

The Flexible alternating current transmission systems (FACTS) is considered one of the most developed technologies applied for enhancing the performance of system due to their ability of adjusting different parameters in the transmission systems such as the buses voltage, the transmission line impedance, the active and reactive powers flow in transmission lines. The static synchronous series compensator (SSSC) is an effective member of the FACTS which is connected in series with the transmission lines and it consists of a solid-state voltage source inverter coupled with a transformer which aims to control and secure the operation of the power system. The main function of SSSC is inserting a controllable voltage in series with the transmission line to control the active and reactive powers flow in transmission lines. Solving the optimal reactive power dispatch (ORPD) problem is nonlinear, non-convex and it becomes a complex problem with integration of the SSSC. The contributions of article include, 1) an efficient and reliable optimization algorithm is developed to solve the ORPD problem and identify the optimal location and ratings of the SSSC, 2) The proposed algorithm is based on modifying the salp swarm algorithm (SSSA) using Levy Flight Distribution and spiral movement of particles to enhance the searching capabilities of the SSA, 3) an efficient model of SSSC based on power injection approach is used for representation the SSSC in ORPD. The ORPD is solved with and without the SSSC controller to minimize power losses and voltage deviations as well as improve the voltage stability. The proposed algorithm for ORPD is tested on the standards IEEE 30-bus and 57-bus systems. The simulation results demonstrate that MSSA is more effective and superior for solving the ORPD compared with some other reported meta-heuristic techniques. Moreover, the system performance is enhanced considerably with optimal inclusion the SSSC.

Research on key technologies of high voltage and large capacity static synchronous series compensator control system

With the rapid development of economy, the structure of power grid is becoming more and more complex, which has brought about uneven distribution of power flow, limited transmission capacity and the decline of power quality. The application of new static synchronous series compensator can quickly and effectively regulate power flow, suppress sub-synchronous oscillation and enhance system stability on the basis of guaranteeing transmission capacity. In practical engineering application, the design of control system and the realization of control algorithm are very important. In this paper, the control system of 220 kV 30MW self-excited SSSC device is developed based on the control and protection platform of serial RapidIO technology. Firstly, the main topology structure of SSSC is introduced, and the two-stage DC voltage stabilization and upper steady-state operation control strategy of SSSC using fast response control method which simultaneously regulates modulation ratio and trigger angle are expounded. Secondly, the dual redundancy control system architecture is designed, and the control system implementation scheme is designed. Finally, the RTDS power in the loop experimental system is designed, and the control algorithm is verified by RTDS experiments. The experimental results show that the control strategy and control system implementation scheme adopted in this paper can realize smooth start-up and exit of SSSC device and flexible regulation of power flow. The developed control system can satisfy the long-term reliable and stable operation of the system, especially the design of redundancy mechanism, and increase the reliability of the device operation. Follow-up static synchronous series compensator project and even FACTS project provide reference.

Effects of SSSC and TCSC for enhancement of power system stability under different fault disturbances

ABSTRACTRecent technological advancement in the field of power electronics has led to the development of FACTS controller to improve the power system stability issues. While various FACTS controller assists in mitigation of power system oscillations, Static Synchronous Series Compensator (SSSC) and Thyristor Control Series Compensator (TCSC) are found to be most suitable for the issue. This paper addresses the modelling and operation of SSSC and TCSC controller in a multi-machine environment. In order to test the effectiveness of the controller, various cases of fault conditions are considered. Since Power System Stabilizers (PSS) are presumably present in a large system, its simultaneous operation along with the TCSC and SSSC are envisaged to improve its action. Results are obtained for the system without compensation, with PSS only and PSS assisted TCSC and SSSC controller. The comparison shows that the PSS assisted SSSC controllers mitigates the power system oscillations more rapidly than earlier and thereby enhancing the overall operation of the controller to stabilize the given system effectively.

Improvement in Frequency Regulation of Interconnected Thermal Power System with Optimal SSSC and SMES Controllers

The level of real and reactive power reserve with only contribution from rotor inertia of generators provides a very small margin of maneuverability in system operation. The use of energy storage device and “Flexible AC Transmission systems (FACTs)” devices solves the problem to a large extent particularly in larger interconnected system. In this work energy storage devices like “Superconducting Magnetic Energy Storage (SMES)” system and “Static Synchronous Series Compensator (SSSC)”, are operated together in different combined two-area thermal system.

LVRT improvement and transient stability enhancement of power systems based on renewable energy resources using the coordination of SSSC and PSSs controllers

This study presents the transient stability and low voltage ride through (LVRT) improvement of IEEE 68-bus system connected with wind farms and photovoltaic (PV) plant through coordination of static synchronous series compensator (SSSC) and power system stabilisers (PSSs) controllers. It is generally accepted that there is a threat to the stability of power systems with the penetration of wind farm and PV plant. Therefore, in order to improve transient stability and LVRT in the power system, this study proposes the application of proportional and integral controllers in PV and wind farm controllers and a combination of PSS and SSSC controllers. Also, adaptive velocity update relaxation particle swarm optimisation algorithm and genetic algorithm have been applied and compared for controllers design.

Designing SSSC, TCSC, and STATCOM controllers using AVURPSO, GSA, and GA for transient stability improvement of a multi-machine power system with PV and wind farms

In this paper, the effects of three FACTS controllers, static synchronous series compensator (SSSC), thyristor-controlled series compensator (TCSC), and static synchronous compensator (STATCOM), on the transient stability of a multi-machine power system in the presence of two 200 MW wind farms based on a doubly fed induction generator (DFIG) and a 120 MW photovoltaic (PV) solar plant are studied. Also, power system stabilizers (PSSs) are installed on four synchronous machines. It is generally accepted that there is a threat to the stability of power systems with the penetration of wind farm and PV plant. Therefore, in order to improve transient stability in the power system, this paper proposes the application of PI controllers in PV and wind farm controllers and a combination of PSS and FACTS controllers, whose coordination is very important. The design problems of the PSS, FACTS, and PI controllers are formulated as an optimization problem, and the adaptive velocity update relaxation particle swarm optimization (AVURPSO) algorithm, gravitational search algorithm (GSA), and genetic algorithm (GA) are employed to search for the optimal controller parameters. These three approaches identify the solution to a given objective function, but they employ different strategies and computational efforts. Therefore, a comparison of their performance is required.

Modified whale optimization algorithm for fractional‐order multi‐input SSSC‐based controller design

SummaryIn this paper, the design of a fractional‐order (FO) multi‐input–single‐output (MISO)–type static synchronous series compensator (SSSC) is proposed with a goal to improve the power system stability using modified whale optimization algorithm (MWOA). The proposed MWOA achieves an appropriate balance between exploitation and exploration stages of the original whale optimization algorithm. The performance of MWOA is validated by employing the benchmark test functions and further contrasted with whale optimization algorithm and other heuristic algorithms like gravitational search algorithm, particle swarm optimization, differential evolution, and fast evolutionary programming algorithms to demonstrate its strength. The proposed FO MISO SSSC controller is optimized by the MWOA technique and tested under single‐machine infinite bus system and further extended to a multi‐machine framework. To demonstrate the superiority of MISO‐type SSSC controller, the results obtained from it are compared with particle swarm optimization and differential evolution–based conventional single‐input–single‐output structured SSSC controllers. The comparison of results of MWOA with that of other methods validates its superiority in the present context.

Power system stability enhancement by fractional order multi input SSSC based controller employing whale optimization algorithm

In this paper, a designing process of fractional order multi input single output (MISO) type static synchronous series compensator (SSSC) using whale optimization algorithm (WOA) is detailed. The controller design task is taken as an optimization task and WOA is utilized to tune the controller parameters. The effectiveness of the proposed controllers is assessed under various disturbances for both single-machine infinite-bus and multi-machine power systems. To demonstrate the superiority of MISO controller for SSSC, results are compared with differential evolution and particle swarm optimization based conventional single input single output (SISO) structured SSSC controllers. It is observed that the MISO control approach yield better damping characteristic than SISO methodologies.

A New Static Synchronous Series Compensator Control Strategy Based on RBF Neuro-Sliding Mode Technique for Power Flow Control and DC Voltage Regulation

This paper presents a new hybrid approach which combines Radial Basis Function neural network with the sliding mode technique to design a Static Synchronous Series Compensator controller for power flow control and DC voltage regulation of an electric power transmission system. The proposed neuro-sliding mode control technique requires reduced number of hidden units and the weights are updated through on-line learning. The proposed technique is robust and does not need the knowledge of the perturbation bounds nor the full state of the nonlinear system (as opposed to existing methods based on Radial Basis Function neural networks). The performance of the proposed controller is validated on an IEEE 9 bus test system. Comparative results with another neural networks control and PI regulators show the effectiveness and satisfactory performance of the proposed controller in dealing with the perturbations considered.

Stability improvement of power systems connected with developed wind farms using SSSC controller

Abstract This paper studies the performance of SCIG wind farm, DFIG wind farm, and a combined wind farm (CWF) during three-phase grid fault. The SCIG and DFIG wind farms are equipped with Static Synchronous Series Compensator (SSSC) whereas the combined wind farm did not have one. Since the CWF is composed of an equal number of Double Feed Induction Generators (DFIGs) and Squirrel Cage Induction Generators (SCIGs), it incorporated the main advantages of both types of generator. More specifically, the SCIG has a lower cost, but its drawback lies in its negative impact on system stability, especially when it operates without a shunt compensator. On the other hand, the DFIG, though more expensive, is better able to maintain the stability of the system. The SCIG and DFIG wind farms are equipped with SSSC controller to control the active and reactive line power flow. The results of a comparative study of DFIG and SCIG wind farms with SSSC and combined wind farm without SSSC during a three-phase grid fault showed that even though the SSSC improved the performance of the DFIG and SCIG wind farms, the CWF without the SSSC controller is found to have the best performance. The stability of the three wind farms is examined using Voltage Stability Index (VSI). All of the test scenarios are simulated with MATLAB.

Evaluation of effect of SSSC stabilizer in different control channels on sub-synchronous resonance oscillations

To increase transmitted power, series capacitors may be used in the transmission lines. A compensated transmission line together with a turbine-generator may cause sub-synchronous resonance (SSR) phenomena in a power system. In this paper, details of dynamic modeling of a single machine power system connected to the network through a transmission line, compensated with a series capacitor, has been presented. Static synchronous series compensator (SSSC) as one of series FACTS devices has been used for damping of the SSR oscillations. For this purpose, a linear damping SSSC-based stabilizer with lead-lag structure is included to SSSC controller. To determine parameters of SSSC stabilizer, a new multi-objective function has been proposed. In this function, in addition to improve stability of critical modes the gain of the stabilizer has been considered. To have stabilizer with minimum phase structure, suitable constraints have been determined and added to the objective function. To optimize the objective function, a recently developed optimization technique known as grey wolf optimization (GWO) algorithm has been applied. The eigenvalues analysis and nonlinear simulations on the IEEE first benchmark model (FBM) power system with a SSSC stabilizer illustrate the effectiveness of the proposed method to suppress SSR oscillations in the studied system.

COA Based SSSC and STATCOM Optimal Controllers Designing with The Aim of Better Damping of Oscillations: A Comparative Study

In this paper, the designing problem of two flexible AC transmission systems (FACTS)-based stabilizers are formulated for a cuckoo optimization algorithm (COA) with an objective function that includes the damping factor and the damping ratio of oscillations. This new optimization algorithm has a strong ability to find the most optimistic results for dynamic stability improvement. Also, its performance in 20 times run is the same as in 1 time run. Single machine infinite bus (SMIB) system has been considered to examine the operation of proposed COA based static synchronous series compensator (SSSC) and static synchronous compensator (STATCOM) controllers. Sudden change in the input power of generator is considered as a disturbance. The effectiveness of the proposed COA based SSSC and STATCOM controller for damping of low frequency oscillations is tested on a weakly connected power system with a disturbance and different loading conditions and their results are compared with each other. The eigenvalue analysis and time domain simulation results are presented to show the effectiveness of these FACTS-based stabilizers. The results obtained revealed the effectiveness of SSSC in comparison with STATCOM in damping power system oscillation and the results confirmed the effectiveness of the COA method for controller parameter optimization.

Controller Design of SSSC for power System Stability Enhancement

In this paper, a novel method is developed for designing the output feedback controller for Static Synchronous Series Compensator (SSSC). In the proposed method, the problem of selecting the output feedback gains for the SSSC controllers is changed into an optimization problem with a time domain-based objective function.Then, it is solved by using the particle swarm optimization (PSO) algorithm that has a strong ability to find the most optimistic results. Only local and available state variables are used as the input signals of each controller for the decentralized design. Therefore, the designed SSSC controller has a simple and easy-to-implement structure. The performance of the proposed controllers is evaluated for both single-machine infinite-bus (SMIB) power system and multi-machine power system. Then, to show the robustness and effectiveness of proposed design approach, the results are presented over a wide variety of system configurations, loading conditions, and disturbances. Analyzing the results reveals that the designed PSO-based output feedback SSSC damping controller has a strong ability in damping power system oscillations. Furthermore, analyzing system performance under different operating conditions shows that the ψ-based controller is superior to the m-based controllers.

Optimal Allocation of Static Synchronous Series Compensator Controllers using Chemical Reaction Optimization for Reactive Power Dispatch

Static synchronous series compensator (SSSC) is one of the most effective flexible AC transmission systems (FACTS) devices used for enhancing power system security. In this paper, optimal location and sizing of SSSC are investigated for solving the optimal reactive power dispatch (ORPD) problem in order to minimize the active power loss in the transmission networks. A new and efficient chemical reaction optimization (CRO) is proposed to find the feasible optimal solution of the SSSC based optimal reactive power dispatch (ORPD) problem. The proposed approach is carried out on the standard IEEE 30 bus and IEEE 57 bus test systems. The optimization results obtained by the proposed CRO are analyzed and compared with the same obtained from genetic algorithm (GA), teaching learning based optimization (TLBO), quasi-oppositional TLBO (QOTLBO) and strength pareto evolutionary algorithm (SPEA). The results demonstrate the capabilities of the proposed approach to generate true and well-distributed optimal solutions.