Fixed Capacitor-thyristor Controlled Reactor Research Articles

Examining the Thyristor-Controlled Reactor's (TCR) Performance to minimize Self-Generated Harmonics.

This work discusses the minimizing of self-generated harmonics in a Thyristor Controlled Reactor (TCR) used in a power distribution system. When a nonlinear load is connected to the system, power quality difficulties arise, including reactive power compensation, harmonics, voltage unbalance, poor power factor, and so on. These flaws degrade the power quality of the system. FACTS and electronics devices are most commonly employed for reactive power correction. A conventional Static VAR compensator is the best option for this application. The static VAR compensator consists of either a fixed capacitor-thyristor controlled reactor (FC-TCR) or a thyristor switched capacitor-thyristor controlled reactor (TSC-TCR). The reactive power demand objective can be met by controlling the conduction angle of TCR. However, the switching operation of the thyristor-controlled reactor reduces power quality by adding self-generated harmonics into the system. The proposed topology in this study outlines the usage of a delta-connected TCR to reduce self-generated harmonics rather than a thyristor controlled reactor (SCR).
 The work carried out in this paper has two major sections
 
 Determine (a) the firing angle range for reactive power adjustment, and (b) the mechanism to control inductive susceptibility. 2. A comparison of three presented methods: a) single delta connected TCR; b) Equally stepped delta connected TCR (ESTCR); and c) Binary stepped delta connected TCR (BTCR).

Enhancement of Power Quality in Power Distribution Systems Using FC- TCR Based Compensation Systems

The development of modern electronic systems and increasing number of application areas (computers, office equipment, rectifiers, converters, speed control devices, uninterruptible power supplies, switched power supplies) has led to harmonic generation and reduced energy efficiency. The majority of loads are inductive in nature and the draw of reactive power has increased in networks and transmission lines resulting in problems with power quality. In addition to efficient power flow in transmission systems, there is also a need to compensate for the reactive power flow in order the meet the requirements of the load and system. As an alternative to traditional solutions, FACTS (Flexible Alternating Current Transmission Systems) has been developed in order to operate electrical systems efficiently and improve stability and power quality. Technological applications such as SVC, STATCOM, SSSC and active harmonic filter are becoming widespread in order to improve power quality. In this study, applications within the scope of FACTS systems are explained and analysis of a fixed capacitor-thyristor controlled reactor (FC-TCR) to improve power factor is discussed. A circuit model of the FC-TCR is developed as a simulation and used to investigate how power factor may be kept within desired limits by adjusting the firing angle of the thyristors under different load conditions. A comparative evaluation has been carried out to determine the effect of FC-TCR by presenting results before and after the load compensation process is applied. From the simulation it is observed that reactive power compensation can be achieved even for varying linear loads.

Dynamic harmonic domain approach to assess performance of three-phase fixed capacitor thyristor controlled reactor (FC-TCR)

Harmonics have become an important issue as the number of non-linear elements and electronic devices coupled to electrical power systems increases by the day. A Fixed Capacitor Thyristor Controlled Reactor (FC-TCR) is widely used in power systems to continuously control reactive power. This paper presents the harmonic analysis of a three-phase FC-TCR under different operating conditions using the Dynamic Harmonic Domain (DHD) technique. The existing Harmonic Domain (HD) method is widely used to obtain the steady-state harmonics in the power grid. It is not possible to calculate transient harmonics using the harmonic domain method. The dynamic harmonic domain technique also provides a solution for the transient condition. The three-phase FC-TCR is simulated in a MATLAB environment and calculates transient harmonic quantities such as apparent power S(t), reactive power Q(t), real power P(t), and distortion power D(t), RMS values, and distortion factors of the three-phase FC-TCR when subjected to voltage disturbance.

Analysis of current harmonics compensation using various active filter topologies

The technological requirements in the industrial and domestic sectors greatly depend on the sensitive and controllable electrical and electronic equipment to meet the application-specific demands, the usage of these nonlinear devices inherently contribute to the degradation of electric power quality, among the various power quality disturbances, Harmonics, which significantly contribute to the waveform distortion has gained the attention among the researchers due to its negative impact on the entire power system network. Hence, the suppression of harmonics has been the focus area in the present context. The paper presents an overview on circuit configuration of three active power filter topologies, delta connected Shunt active filter, Delta-connected Fixed Capacitor Thyristor Controlled Reactor (FCTCR) and delta connected Hybrid filter. Paper also investigates the effectiveness of instantaneous active reactive power theory, Synchronous reference frame theory And Adaptive detection algorithm as control strategies for the suppression of the harmonics under different power system network conditions. Results of the simulation studies are presented in the paper to assess the performance of designed filter with different control strategy for the mitigation of current harmonics in the proposed power system network, simulation studies are carried out using MATLAB/SIMULINK.

Fault Tolerant Sliding Mode Controller Design Subject to Sensor Faults for Output Voltage Regulation of a Self-Excited Induction Generator

This paper aims to improve the performance of the output voltage regulation of the Self-Excited Induction Generator (SEIG) with fixed capacitor-thyristor controlled reactor (FC-TCR) structure in case of sensor faults. A sliding mode controller (SMC) is designed to generate the triggering angle of the FC-TCR to regulate the output voltage. The performance of proposed SMC is firstly tested without sensor faults and high success in tracking the reference is obtained. Since an additive fault occurs on the sensor, SMC performs well tracking dynamic but is on the incorrect reference. Therefore, Radial Basis Function Neural Network (RBFNN) is trained accurately with the 2% mean squared error (MSE) by taking the stator currents, triggering angle and generator speed as inputs, whereas the output voltages of the SEIG are outputs. Further, fault detection architecture is well designed with a voltage error index calculated by subtracting the sensor output from the estimated output. The threshold based selector reconfigures the controller well. The simulation results show that in case of sensor faults and various loading conditions, proposed fault tolerant SMC remains the actual output voltage of the SEIG at real reference with maximum 2.2% steady state error in a finite time.

Design and implementation of fault tolerant fractional order controllers for the output power of self-excited induction generator

In this paper, a static volt-ampere-reactive compensator (SVC) composed of fixed capacitor-thyristor controlled reactor (FC-TCR) is employed to regulate the terminal voltage of self-excited induction generator (SEIG) in the purpose of controlling the output power. In addition, the speed of the generator is adjusted by robust proportional-integral-derivative (PID) in order to regulate the frequency. Fractional order PID (FOPID) and Tilt-PID (T-PID) controllers are proposed to adjust the triggering angle of FC-TCR. The objectives of the paper are to design the optimal voltage controller with a robust PID frequency controller and to maintain the output power at a desired level in case of voltage sensor faults. In this regards, nonlinear autoregressive network with exogenous inputs (NARX) and small signal models of the SEIG are constructed where triggering angle and generator speed are inputs, whereas terminal voltage and frequency are outputs, respectively. Training of the NARX model is achieved with a high regression value (R2 = 0.99) where the accuracy of the small signal voltage model is 82%. After comparing the accuracy of the models, NARX-based fault detection architecture and fault tolerant controller are designed in order to avoid incorrect control of the output power. To establish the effectiveness of proposed fault tolerant controllers, simulation studies are conducted using particle swarm optimization (PSO). The designed controllers are performed experimentally on three-phase 5.5 kW, 400 V, 50 Hz, balanced loaded SEIG to confirm the effectiveness. The system is tested with proposed controllers under the healthy sensor, faulty sensor and dynamic reference conditions. Results give good agreement with simulation results and designed fault tolerant T-PID controller performs better tracking dynamics with small deviations whether the voltage sensor is faulty or not.

A Hybrid Compensator Configuration for VAR Control and Harmonic Suppression in All-Electric Shipboard Power Systems

This paper proposes a cost-effective compensator to suppress harmonics and compensate the power factor of all-electric shipboard power systems (SPSs). This compensator, which is based on a fixed capacitor-thyristor controlled reactor (FC-TCR), behaves as a low-pass filter and therefore can reject both low and high-order harmonics. Moreover, the FC-TCR compensator is featured by the low switching losses; hence, it can effectively be implemented for low and medium voltage applications. The design of the filter is detailed via equivalent lossy circuits, which exhibit the mechanism of the harmonic mitigation. Furthermore, theoretical analyses and mathematical developments are suggested to enhance the filtering performance. Besides, details of the Fixed-Point iteration technique which is applied to extract the firing angle of the TCR are conducted. A practical SPS is selected to ensure and demonstrate the performance of proposed methodology via thorough simulations under MATLAB/Simulink environment. The obtained results verify the theoretical analyses and confirm the effectiveness of proposed solution.

THE COMPARATIVE STUDY OF STATCOM WITH FC-TCR AND SSSC

The Flexible Alternating Current Transmission Systems (FACTS) device deals with the control of power flow, alternating current of transmission line and immediately respond towards the stability problems of the system. The present paper show that how the FACTS devices enhance the different parameter of the power systems like power transfer capacity of line, system stability etc. In MATLAB a simplified transmission system is modeled and the resultant power (PQ) and voltage profiles are studied as an uncompensated system. Now the same transmission system is simulating with FACTS device i.e. Static Synchronous Series Compensator (SSSC), Fixed Capacitor Thyristor Controlled Reactor (FC-TCR) and Static Synchronous Compensator (STATCOM). The result obtained after simulation provide the power and voltage profiles, are analyzed as a compensated system. Finally we found that a compensated system have better voltage profile and power flow w.r.t. an uncompensated system.

Proposing and Evaluation of SC Techniques for Variable Speed High-Power Operation of SEIG

This work presents a novel methodology for variable speed high power Transfer Capability of a self-excited induction generator (SEIG). The proposed methodology is based on the selection of a suitable firing angle of Fixed Capacitor-Thyristor Controlled Reactor (FC-TCR) for achieving constant rated stator current. WDSEIG would produce a variable speed high power without overheating under variable wind speed and connected load. The analytical approach for the proposed methodology has been implemented to predict the optimal operating firing angle of FC-TCR for full load stator current achievement within the allowed operating range of load and prime mover speed. Also, Soft Computing (SC) techniques have been implemented based on Harmony Search Algorithm (HSA), Flower Pollination Algorithm (FPA), and Moth-Flame Optimization (MFO) algorithm to achieve the proposed methodology. A comparison between different SC techniques, analytical approach and experimental work are given and evaluated to verify SC techniques accuracy. This evaluation study can be useful in specifying the appropriateness of the SC techniques for High Power Transfer Capability for a SEIG.

Design of a Thyristor Controlled <italic>LC</italic> Compensator for Dynamic Reactive Power Compensation in Smart Grid

This paper presents a thyristor controlled LC (TCLC) compensator for dynamic reactive power compensation in a smart grid system. Compared with the traditional static var compensators like a fixed capacitor-thyristor controlled reactor (FC-TCR) which generates low order harmonic currents, the proposed TCLC can significantly mitigate the injection of harmonic currents. In this paper, the design of the TCLC parameters is investigated with the considerations of its reactive power compensation range and harmonic currents rejection. And a control method based on the generalized instantaneous reactive power theory is proposed. Moreover, representative simulation and experimental results of the proposed three-phase three-wire TCLC are presented to show its effectiveness in dynamic reactive power compensation in comparison with the traditional FC-TCR and parallel combination of FC-TCR and passive power filter.

Integrating FACTS controllers in unbalanced distribution systems to restore the balanced operation using ANN

Artificial neural network (ANN) is applied in this work for integrating flexible AC transmission systems (FACTS) in the distribution system to overcome the unbalanced operation problems. Fixed capacitor-thyristor controlled reactor (FC-TCR) as one of FACTS devices is introduced in this paper to cancel the negative and zero sequence line currents caused by the unbalanced load to restore balanced operation. Three-phase unbalanced load is utilised and FACTS controller in the form of FC-TCR type is integrated to the load in the form of three-phase variable susceptances whose values are adjusted by the thyristor firing angles connected in parallel with the unbalanced load. Many test cases are applied to the system by changing the values of the load admittances, then the corresponding firing angles for each phase of the FC-TCR are obtained to restore the system balanced operation. The three-phase load admittances and the corresponding thyristors firing angles of FC-TCR device are set to be the input and output signals to the ANN respectively, in order to train the network. In order to test the capability of the proposed scheme, two test cases are used in order to restore the balanced operation in each case.

Design and experimental analysis of an advanced static VAR compensator with computer aided control

This study presents integration of a real-time energy monitoring and control system with an advanced reactive power compensation unit based on fixed capacitor-thyristor controlled reactor (FC-TCR). Firing angles of the thyristors located in the FC-TCR are controlled by a microcontroller in order to keep the power factor within the limits. Electrical parameters of the system are measured by specially designed circuits and simultaneously transferred to the computer via a data acquisition board. Thus, real time data of the system can be observed through a visual user interface. The data obtained is not only analyzed for control process, but also regularly saved into a database. The system has been tested in laboratory conditions under different load characteristics and experimental results verified that the system successfully and accurately achieves compensation process against the all operational conditions.

Mitigation of Voltage flicker and reduction in THD by using STATCOM

Voltage flicker is considered as one of the most severe power quality problems (especially in loads like electrical arc furnaces) and much attention has been paid to it lately. Due to the latest achievements in the semiconductors industry and consequently the emergence of the compensators based on voltage source converters, FACTS devices have been gradually noticed to be used for voltage flicker compensation. This paper covers the contrasting approaches; dealing with the voltage flicker mitigation in three stages and reduction in total harmonic distortion and assessing the related results in details. Initially, the voltage flicker mitigation, using FCTCR (Fixed Capacitor Thyristor Controlled Reactor), was simulated. Secondly, the compensation for the six-pulse as well as 12-pulse Static Synchronous Compensator (STATCOM) has been performed. In this case, injection of harmonics into the system caused some problems which were later overcome by using 12-pulse assignment of SATCOM and RLC filter (three phase harmonic filter). The obtained results show that STATCOM is very efficient and effective for the flicker compensation as well as harmonic sprectrum. All the simulations have been performed on the MATLAB Software. DOI: http://dx.doi.org/10.11591/ijece.v3i1.1951

Compensation of Voltage Flicker by Using Facts Devices

Voltage flicker occurs when heavy loads are periodically turned on and off in a weak distribution system. If the distribution system’s short circuit capacity is not large enough, voltage fluctuations will occur. Voltage flickering can be extremely harmful to sensitive electronic equipment. Computerized equipment requires stable voltage to perform properly. This paper covers the contrasting approaches; dealing with the voltage flicker mitigation in three stages and assessing the related results in details. Initially, the voltage flicker mitigation, using FCTCR (Fixed Capacitor Thyristor Controlled Reactor), was simulated. Secondly, the compensation for the Static Synchronous Compensator (STATCOM) has been performed. In this case, injection of harmonics into the system caused some problems which were later overcome by using 12-pulse assignment of SATCOM and RLC filters. The obtained results show that STATCOM is very efficient and effective for the flicker compensation. All the simulations have been performed on the MATLAB Software

Hardware Circuit Implementation of Automatic Control of Static Var Compensator (SVC) using Micro Controller

The design, Fabrication of 1Kvar 1-phase fixed capacitor-thyristor controlled reactor (FC-TCR) type SVC based on microcontroller have been developed in the laboratory for SMSL(Single Machine Single Load) Test System. The test system is setup in the laboratory with a 3-phase Synchronous Machine of 5kva capacity and a 1-phase Induction Motor of 1HP Rating. Brake test have been performed on the Induction Motor by taking the supply from one of the phases of Synchronous Generator. The bus voltage is fall down from 230 V to 195 V on Full Load. Automatic control circuit Hardware of this SVC have been designed and fabricated based on Microcontroller LPC 2148 chip, the most modern industrial controller. The same test system also has been tested with SVC automatic control circuit and experimental results have been presented in this paper. The P-V Curves of the SMSL Test system with and without SVC Control have been plotted which shows the effectiveness of Automatic control of SVC on Voltage Stability enhancement.

Dynamic companion harmonic circuit models for analysis of power systems with embedded power electronics devices

In this paper a methodology that extends the dynamic harmonic domain (DHD) analysis of large networks is presented. The method combines DHD analysis and discrete companion circuit modeling resulting in a powerful analytic technique called dynamic companion harmonic circuit modeling. It provides for a complete dynamic harmonic analysis of the system while preserving the advantages of discrete companion circuit models. The methodology is illustrated by its application to a three-node power system, where reactive power compensation is achieved using a fixed-capacitor, thyristor-controlled reactor (FC-TCR) and its control system.

The Resonance Analysis Caused by Harmonics in Power Systems Including Thyristor Controlled Reactor

The static VAR compensators having fixed capacitor thyristor controlled reactor (FC-TCR) used to improve voltage stability in power systems are nonlinear elements. The fixed capacitor group will produce reactive power while the thyristor controlled reactor will consume reactive power in compensators having FC-TCR. Changing the firing angles of TCR provides the reactive power variation of the system since the reactive power production of capacitors is fixed at a determined voltage level. In some cases, the variation of these firing angles will cause the harmonics in the system. In this study, TCR's are discussed to be harmonic sources and the resonance case caused by harmonics has been investigated with Fourier Matrix Model and MATLAB Software.

Using a static VAr compensator to balance a distribution system

An algorithm for applying a fixed capacitor-thyristor controlled reactor (FC-TCR) type of static VAr compensator (SVC) in the distribution system to dynamically balance a system is introduced. With a newly developed individual phase control scheme, an SVC can reduce negative sequence current caused by the load to improve system balance. Since the control circuit is governed by a microcomputer, which replaces the traditional discrete load switching and makes the capability of rapid and dynamic balancing of the system become possible. In addition, the power factor can be improved simultaneously by selecting an appropriate amount of capacitive/inductive compensation. This paper presents a mathematical model for computer simulation and control of a delta connected SVC to achieve the purpose of negative sequence reduction. Some computer simulation and scaled laboratory test results are discussed.

Operation of a Fixed Capacitor-Thyristor Controlled Reactor (FC-TCR) Power Factor Compensator

A fixed capacitor-thyristor controlled reactor (FC-TCR) type of power factor compensator with thyristor-controlled series R-L load is analysed using an approximate and also a more exact circuit. The variation of power and power factor before and after compensation is examined for both cases. It is shown that considerable power factor improvement can be achieved in the circuit for low values of load thyristor firing- angle. However, for higher values of firing-angle, any improvement is obtained at the expense of additional. power losses.

Operation of a Fixed Capacitor-Thyristor Controlled Reactor (FC-TCR) Power Factor Compensator

Operation of a Fixed Capacitor-Thyristor Controlled Reactor (FC-TCR) Power Factor Compensator