Design Of Static VAR Compensator Research Articles

Cuckoo Search Approach for Optimal SVC Design in A Multimachine Power System

In this paper, a new metaheuristic method, the Cuckoo Search (CS) approach, based on the life of a bird family is proposed for the optimal design of a Static Var Compensator (SVC) in a multimachine environment. The SVC parameter tuning problem is converted to an optimization problem which is solved by the CS approach. The performance of the proposed CS-based SVC (CSSVC) has been compared with Particle Swarm Optimization (PSO) based SVC (PSOSVC) under various operating conditions. The superiority of the suggested technique in damping oscillations and enhancing voltage profile over a wide range of operating conditions and system configurations is confirmed through eigenvalue, performance indices, and time domain simulation results over the PSO.

Harmonic Performance Analysis of Static Var Compensator Connected to the Power Transmission Network

The static var compensator (SVC) is a device which is designed to compensate reactive power, increase voltage stability and to reduce voltage fluctuations. Thyristor controlled reactors (TCRs) are composed of reactors in series with bidirectional pair of thyristors. Current through reactors can be continuously controlled by changing the firing angle of thyristor valves, thus
 the inductive power can be easily controlled. Typical applications of TCRs in AC systems are voltage stabilization and temporary overvoltage reduction, stability improvement, damping of power oscillations and load balancing. In this paper, harmonic performance analysis of SVC equipped with TCRs is presented. SVCs utilizing TCRs generate harmonic currents and therefore it is necessary to determine the effect of harmonics generated by the SVC on the power system and its elements. This includes interaction of the SVC with the system, the SVC performance under balanced and unbalanced operating conditions and finally, evaluation of countermeasures such as installation of harmonic filters. In order to carry out these analysis, it is necessary to determine harmonic characteristics of the network at the point of SVC connection, existing levels of harmonics, and to know appropriate standards regarding acceptable harmonic levels in the power system. Since harmonic distortions in the system are caused by the interaction between SVC and the system, all system contingencies which may affect system’s frequency response should be evaluated. Detailed power system model should be considered to make sure that parallel resonance points of system do not directly coincide with characteristic harmonics from the SVC. Harmonics generated by SVCs are largely dependent on the operating point within the SVC characteristic. A conservative approach is to use the maximum values of harmonics generated within the spectrum irrespective of the operating point. The results of harmonic performance analysis are important for appropriate design of SVC. Harmonic performance analysis related to SVC application which are presented in this paper include the determination of: frequency response of the transmission network impedance required for the specification and design of filters; the effects of SVC generated harmonics on the power system; the overall filter requirements and countermeasures to reduce harmonics to acceptable levels.

New economical design of SVC and passive filters to improve power quality at railway substation: a case study

In electrified railways, harmonics and low power factor (PF) are typical power quality problems. The traction system of 25 kV, single phase, 50 Hz that exists in India has been taken for this case study. Most of the locomotives are single-phase and draw very high currents. The load is of highly variable nature and introduces high pollution into the power supply lines and distorts PF. The field measurement data in a tractions substation were collected and analyzed. The main objective is to identify an appropriate compensation strategy, which is cost-effective and reliable. This paper proposes a combined system of harmonic filters and thyristor-controlled reactors (TCRs) for PF improvement and reactive power compensation with new economical design of static VAR compensator (SVC). Generally, the SVC requires high-voltage switching of capacitors and inductors at very high cost. In the new concept, the voltage is stepped down to 600 V for reactors and divides into 32 parallel TCRs to handle high current in steps by switching without continuous control of firing angle. This technique makes system reliable and cost-effective. The TCR compensates reactive power dynamically and suppress the possibility of resonance between the SVC and the grid. The proposed system is verified using MATLAB simulation for harmonic filters. The simulated results are found to be quite satisfactory. The proposed solution is cost-effective and highly reliable than conventional SVCs and reduces harmonics to levels recommended in IEEE-519 standards.

Review of Impacts of Static Var Compensator Allocation on Radial Distribution Networks

ABSTRACT This paper primarily focuses on an investigative study on allocating Flexible AC transmission system (FACTS) devices on radial distribution systems. The FACTS device that is used in this paper is static var compensator (SVC). In this paper, SVC is placed on each bus except substation bus and study the results to find the best location for allocation. A design of SVC was done by fixed reactance method. The total power loss of network and voltage of nodes have been analyzed for each allocation and the sequences of each implementation have been compared to find the best location of SVC. The proposed algorithm has been executed on IEEE 33-bus and 69-bus standard test systems.

Design of SVC Damping Controller Based on Biogeography-Based Optimization Algorithm

On account of that common subsynchronous resonance controllers cannot well adapt to the time-varying and nonlinear characteristics of power system, biogeography-based optimization (BBO) algorithm is introduced to design subsynchronous damping controller optimally based on the mechanism of suppressing SSO by static var compensator (SVC). The simulatied results of Jinjie plant indicate that the subsynchronous damping controller optimized by BBO algorithm can remarkably improve the damping of torsional modals and thus effectively depress the multimodal SSO, ensuring the safety and stability of units and power grid operation.

New Coordinated Design of SVC and PSS for Multi-machine Power System Using BF-PSO Algorithm

Nowadays, flexible AC transmission system (FACTS) devices are increasingly used in power systems. They have remarkable effects on increasing the damping of the system. In this paper, a bacterial-foraging oriented by particle swarm optimization (BF- PSO) algorithm is employed to design the coordinated parameters of power system stabilizer (PSS) and static VAR compensator (SVC). With regard to nonlinearities of power system, linear methods can’t be used to design coordinated parameters of controllers. In this paper, nonlinear model of power system and SVC is used to design parameters of PSS and SVC. For this purpose, this design problem is firstly converted to an optimization problem and then the BF-PSO algorithm is used to solve it. Simulations are carried out on four machine 11 bus power system in MATLAB software. The results confirm the efficiency of the proposed method for stabilizing the power system oscillations. Comparing BF-PSO algorithm with other intelligent methods, (PSO, BFA) verifies better performance of the BF-PSO method.

발전소 소내전력 고조파 및 역률 개선용 SVC 개발에 관한 연구

The power system has to maintain its synchronism from transient disturbances and oscillations. To achieve this, the static var compensator(SVC), which is a flexible AC transmission system(FACTS), is applied to the power system. SVC using an advanced control algorithm improves the stability of power system. This paper is a study on design of SVC to improve harmonics and power factor of power plant. The proposed SVC analyzes harmonics, voltage drop and reactive power in real time. On the basis of the analysis of the data, the SVC using a switching control algorithm decreases harmonic signals and increases the power factor. The experimental results show that the proposed SVC enhances the stability of power system.

Design of Static Var Compensator for Power Systems Subject to Voltage Fluctuation Satisfying Bounding Conditions

This paper presents the design of a static var compensator for power systems subject to voltage fluctuation by using a known framework comprising the principle of matching and the method of inequalities. In the design formulation, all possible voltage fluctuations are treated as persistent signals having uniform bounds on magnitude and slope. The principal design objective is to ensure that the rotor angle, the generator terminal voltage and the voltage of the nearby bus always deviate from their nominal values within the allowable ranges for all time in the presence of any possible voltage fluctuation. By virtue of the framework, it is clear that once a solution is found, the system is guaranteed to operate satisfactorily in regard to the design objective. The numerical results demonstrate that the framework adopted here is suitable and effective, thereby giving a realistic formulation of the design problem.

Analysis and controller design of static VAr compensator using three-level GTO inverter

A static VAr compensator (SVC) using a three-level GTO voltage source inverter (VSI) is presented for high-voltage, high-power applications. The three-level VSI has lower harmonic components and higher DC-link voltage than the two-level VSI and thus can be operated at lower switching frequency (f/sub sw/<500 Hz) without excessive harmonic contents. From the DQ-transformed equivalent circuit of the presented SVC system, DC and AC analyses are carried out to find the steady-state and the dynamic characteristics of the system. Based on the open-loop transfer function of the system, a controller is designed to achieve fast dynamic response. The experimental results confirm the theoretical analyses and controller design.