New topology for harmonic-free, dynamic VAr compensator using unidirectional power switches (original) (raw)
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PERFORMANCE ANALYSIS OF THYRISTOR-SWITCHED CAPACITOR (TSC) STATIC VAR COMPENSATOR (SVC
In an electric utility network, it is desirable to regulate the voltage within a narrow range of its nominal value (±5% range around their nominal values). Since the load varies from time to time, the reactive power balance in a grid varies as well. It can be shown that the voltage drop on the line is a function of the reactive power flowing on the line. To control dynamic voltage swings under various system conditions and thereby improve the power system transmission and distribution performance, a fast acting Static VAr Compensator (SVC) is required to produce or absorb reactive power so as to provide the necessary reactive power balance for the system. The function of the SVC is to maintain the voltage of the bus connected at a constant value. In this paper an SVC configuration known as Thyristor-Switched Capacitor (TSC) is examined, as applied to shunt reactive compensation. The compensator was connected to the load end of a system operating at 0.7 power factor. By supplying some value of reactive power, it raised the power factor to an optimal value of 0.96, thereby improving the efficiency of the system.
International Journal of Research, 2016
Modern Electrical power transmission system is developing and load demands are increasing, problems of voltage flicker and voltage stability has become important subjects in Power System. Now-a-days Flexible AC Transmission System (FACTS) has become a subject of interest for power System Engineers. In this paper, effects of Thyristor Switch Capacitor (TSC), which is one of FACTS Devices, on load voltage are estimated and checked. By this Technology large and slow, old operating Circuit Breakers are eliminated. The modeling and Simulation of TSC are verified using MATLAB 7.8, SimPower system Block set. Proposed technology allows the steady state and dynamic performance of TSC on transmission system by regulating Voltage through generating or absorbing reactive power and accordingly Compensation is carried out. IndexTerms: receiving end voltage (Vr); SVC; gate pulse; sending end voltage(Vs) and Thyristor Switched Capacitor(TSC); SVC Controller; Voltage regulator; MATLAB
Hybrid var compensator with improved efficiency
2014
In modern electrical networks thyristor-switched capacitors (TSC) are most used devices for VAR compensation. These devices don’t contain rotating parts and mechanical contacts, provide a stepwise control of reactive power and no generation of harmonics to the network. However, with the help of TSC it’s not possible to ensure smooth control of reactive power and capacitor banks (CB) are exposed to the negative impact of higher harmonic components of the network voltage. Hybrid VAR compensator don’t have such drawbacks. It consists of active filter (AF) and capacitor bank with discrete regulation. The main drawback of such systems is the necessity of accessing all six terminals of CB, while most of them are manufactured with three terminals, internally delta-connected. In the article, the topology and control system of hybrid VAR compensator free from beforementioned drawback, is proposed. The control system provides operating modes of overcompensation or undercompensation reactive p...
Design and Implementation of Thyristor Switched Capacitor for Reactive Load
International Journal for Research in Applied Science and Engineering Technology
This paper deals with design and implementation of thyristor switched capacitor for voltage regulation and reactive power compensation. Thyristor switched capacitor based static VAR compensator has been proposed for single phase system at static and dynamic load conditions. In this scheme capacitor values are chosen in different ranges. Excessive inductive reactive powers absorb by thyristor switched capacitor and maintain voltage stability. The effect of TSC based SVC on load voltages are also analyzed. Experimental results shows substantial improvement in voltage regulation and reactive power compensation is achieved by TSC compensator.
Hardware Circuit Implementation of Static VAr Compensator (SVC) with Thyristor Binary Compensator
— Electrical distribution systems are incurring large losses as the loads are wide spread, inadequate reactive power compensation facilities and their improper control. In solution the experimental studies of static VAr compensator (SVC) with thyristor binary compensator is carried out. The work deals with the performance evaluation through analytical studies and implementation of hardware circuit model of SVC at single phase, 50Hz, 2kVA transformer. The SVC consisting of thyristor switched capacitor bank in binary sequential steps. This compensation technique facilitates control on the reactive power depending on load requirement so as maintain power factor near unity always, which results in efficient electrical power system. Index Terms-reactive power, static VAr compensator, thyristor binary compensator, capacitor bank, binary sequential steps, hardware circuit model, power factor, electrical power system.
VAR Compensation on Load Side using Thyristor Switched Capacitor and Thyristor Controlled Reactor
2021
Generally, AC loads are the inductive loads which are reactive in nature. These loads, thus, demand and draw reactive power from the supply source. If these loads draw large lagging current from the source, this will cause excessive voltage drop in the line, which can even cause the voltage collapsing in the line itself if the drop in the line is excessively high. VAR compensation means efficient management of reactive power locally to improve the performance of AC power systems. In this paper, Static VAR Compensator, using TSC (Thyristor Switched Capacitor) and TCR (Thyristor Controlled Reactor), is designed and simulated in MATLAB to maintain the power factor of power system nearly to unity at all times. TSC and TCR are basically shunt connected capacitors and inductor respectively whose switching (of capacitors) and firing angle control (of inductor) operations are carried out using thyristors. The purpose of capacitors is to supply lagging VAR as per the demand by the connected ...
An efficient switched-reactor-based static VAr compensator
IEEE Transactions on Industry Applications, 1994
A new static var compensator is presented in this paper. To overcome the problems of large low-order harmonics and slow response associated with conventional thyristor-controlled-reactor based compensators, a pulse-width-modulated (PWM) ac converter is used to control the reactances of switched reactors. Yet unlike the PWM static var compensators previously reported in the literature, the proposed compensator has a simpler structure and its gating signals are easier to implement. Moreover, it does not require synchronization with the ac mains. The proposed concept was verified rough a l-kvar prototype and the measured experimental results prove that either leading or lagging reactive power can be achieved through simply duty cycle control.
A Review on Reactive Power Compensation Technologies
— In general, the problem of reactive power compensation is viewed from two aspects: load compensation and voltage support. In load compensation the objectives are to increase the value of the system power factor, to balance the real power drawn from the ac supply, compensate voltage regulation and to eliminate current harmonic components produced by large and fluctuating nonlinear industrial loads .Voltage support is generally required to reduce voltage fluctuation at a given terminal of a transmission line. This paper presents an overview of the state of the art of static VAR technologies. Static compensators implemented with thyristors and self-commutated converters are described. Their principles of operation, compensation characteristics and performance are presented and analyzed. A comparison of different VAR generator compensation characteristics is also presented. New static compensators such as Unified Power Flow Controllers (UPFC), Dynamic Voltage Restorers (DVR), required to compensate modern power distribution systems are also presented and described.
The conventional reactive power in single-phase or threephase circuits has been defined on the basis of the average value concept for sinusoidal voltage and current waveforms in steady states. The instantaneous reactive power in three-phase circuits is defined on the basis of the instantaneous value concept for arbitrary voltage and current waveforms, including transient states. A new instantaneous reactive power compensator comprising switching devices is proposed which requires practically no energy storage components.
A solid state high performance reactive power compensator
1990
A high performance reactive power compensator is presented and analyzed. The volt-ampere reactive (VAr) compensator consists of a three-phase current-regulated pulse width modulated voltage-source inverter connected to a self-controlled DC bus. Reactive power compensation is achieved by forcing the inverter output current to follow a reactive sinusoidal reference waveform at a constant switching frequency. The scheme is discussed in terms of principles of operation, power and control system design, and the analysis under transient operating conditions. Simulated results obtained with the PSpice simulation software package for steady-state and transient operating conditions are presented.>