EPE Association: EPE 1995 - 36 - Dialogue Session DS3d: Reactive Power Compensation

EPE 1995 - 36 - Dialogue Session DS3d: Reactive Power Compensation
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1995 - Conference > EPE 1995 - 36 - Dialogue Session DS3d: Reactive Power Compensation

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   Static VAR Compensator for 3-Phase Induction Motors
By A. A. Mahfouz; O. P. Malik [View]
[Download]

Abstract: This paper describes the use of static reactive power compensation (SVC) with 3-phase induction machines to provide a unity power factor operation. The compensator consists of 3-phase pulse width modulated (PWM) voltage source inverter connected to either a self or independently controlled dc bus. The voltage source PWM inverter is connected to the induction machine as either a shunt or series type SVC. The main advantage of this scheme is that it corrects the power factor at the load end without the need to sense and calculate the associated reactive power component at the source end. The PWM technique applied here is based on space vector modulation (SVM) principle and is implemented using a 12 MHz 16-bit microcontroller 80C196KB.

   A NOVEL VARIABLE SPEED CONSTANT FREQUENCY GENERATION SYSTEM WITH VOLTAGE REGULATION
By A. Mebarki; R.T. Lipczynski [View]
[Download]

Abstract: This paper investigates the design, development and implementation of a closed loop control system to regulate the voltage and frequency of a 3-phase AC generator regardless of rotor speed and load variations. This is directed towards such generators being powered by variable speed prime movers such as windmills or diesel engines. Experimental results show the validity of the proposed strategy. The system may also be controlled so as to maximise overall system efficiency.

   NOVEL ERROR TRACKING MODE AC CURRENT WAVEFORM CONTROL METHOD AND ITS AC FILTER DESIGN PROCEDURE
By Masaaki Ohshima; Eisuke Masada [View]
[Download]

Abstract: The error tracking mode (ETM) control is a novel switching algorithm for the current waveform regulation in voltage source power conversion systems (PCS´s) which can generate an arbitrary current waveform and guarantees the error between the target current and the actual one to be less than an arbitrary value given beforehand. Therefore. ETM control can operate a voltage source PCS as a current amplifier. ETM control also assures the minimum continuous on and off time of main switching devices. To connect with an utility network. it is necessary for PCS´s to suppress harmonics in both current and voltage at the point of common coupling (PCC). In the worst case, voltage oscillation would occur due to the resonance of capacitance in utility networks at the switching frequency. Implementation of an ac filter to a PCS is an effective means to prevent such voltage oscillation and to reduce both voltage and current ripples. In this paper, ETM control method and its optimum ac filter design procedure are proposed and their characteristics are discussed.

   A COMPARISON STUDY ON INSERTING THYRISTOR CONTROLLED SERIES COMPENSATION IN POWER SYSTEMS
By S. Maginier; S. Bacha; N. Hadjsaid; R. Feuillet [View]
[Download]

Abstract: This paper presents two ditferent methods dealing with the insertion of Thyristor Controlled Series Compensation (TCSC) in power systems. Both methods work with time domain simulation. This is in order to study dynamic and steady state performances of TCSC. The first method is based on the well known Bergeron's method and the second one on the averaged model. Comparison between these methods are achieved and shown in this paper. The advantage and the drawback of each method is clearly pointed out.

   ITERATIVE HARMONIC SIMULATION OF A THYRISTOR CONTROLLED REACTOR AND A POWER TRANSMISSION SYSTEM
By J. Arrillaga; J. GonzaIez; J. Cidras [View]
[Download]

Abstract: This paper describes an iterative algorithm (IHA) developed to study the harmonic interaction that exist between TCR (thyristor Controlled Reactor) compensators and the Transmission System. The generation of non characteristic triplen and even harmonics and their propagation along the line are accurately predicted by the lHA algorithm.

   HARMONIC TRANSFER IN HVDC SYSTEMS UNDER UNBALANCED CONDITIONS
By Kadry Sadek; Marcos Pereira [View]
[Download]

Abstract: This paper presents a method developed to calculate the harmonic interactions between AC and DC side, with relatively simple formulas and tables. Considerations are made about the transfer of harmonics between AC/DC converters.

   Optimisation of the Number of Levels in a Multi-Level Advanced Static Var Compensator
By D. Scheidecker; S.B. Tennakoon [View]
[Download]

Abstract: An investigation of the technical and economic merits of an N-Level Advanced Static Var Compensator (ASVC) was made. A general analysis of the multi-level ASVC was carried out and performance indices were determined for levels ranging from 3 to 14. Special interest was given to harmonic performance based on a selective harmonic elimination strategy, device utilisation and economic considerations. As the number of levels is increased more harmonics can be eliminated, but the complexity and the expense of the convertor is increased. The device and convertor utilisation considerations show that a high number of levels is not economic and a good compromise is the interconnection of phase shifted 6-level bridge convertors.

   CONTROL OF STATIC VAR COMPENSATOR FOR OPTIMAL FLICKER REDUCTION
By G. De Préville; O. Lapierre; G. Bornard [View]
[Download]

Abstract: This paper describes a 51MVAR Static Var Compensator (Fixed Capacitors / Thyristors Controlled Reactors: FC/TCR) for Arc Furnaces connected to 11kV network in Egypt, to reduce voltage variations on bus line. We present a new control based on internal model control concept for high performance dynamic compensation of flicker. The electronic control is based on Fully Digital Processor System (FDPS). We also describe the power sections with up to date modular technology including optical firing system and thyristors monitoring system to monitor good health of thyristors. Comments on simulations and results conclude this paper.

   A PRACTICAL APPROACH TO HARMONIC CURRENT COMPENSATION BY A SINGLE·PHASE ACTIVE FILTER
By M. Machmoum; N. Bruyant; S. Siala; R. Le Doeuff [View]
[Download]

Abstract: This paper deals with simultaneous compensation of harmonic currents and fundamental reactive power by a voltage single-phase active filter. A simple method which allows to separate the fundamental component of load current into its harmonic components is proposed. The modelling of the active filter parameters, the regulation of the harmonic currents and the capacitor dc voltage are also discussed. Experimental results of the system steady-state and transient performances, and the ability to reduce the distorsion due to the current harmonic components are presented.

   REAL-TIME SIMULATOR MODEL OF AN ADVANCED STATIC VAR COMPENSATOR
By M.M. de Oliveira; A. Ekstrom [View]
[Download]

Abstract: The paper describes a scaled model of an Advanced Static Var Compensator or Static Condenser for realtime simulation studies. The Advanced Static Var Compensator is composed of two Thyristor Switched Capacitors and a twelve-pulse forced-commutated Voltage-Source Converter. Similarities and special characteristics of the adopted control system compared to a conventional Static Var Compensator are discussed. Results from the model at both symmetrical and non-symmetrical operation under transient conditions are reported.

   NEW STRATEGY FOR NON-ACTIVE POWER COMPENSATION
By W. Koczara; R. Teofilak; M. Rukat; L. Grzesiak [View]
[Download]

Abstract: This paper takes into consideration a novel harmonic compensation method. The method bases on auxiliary Active Harmonic Filter, that is added to an Input Converter. The aim of the Input Converter is to compensate reactive power in the supply line with relatively low switching frequency. On the other hand the Active Harmonic Filter enables improving the shape of the current taken from the supply line. It is designed for much lower power rating and operates with higher switching frequency. Simulation results and laboratory tests are presented in the paper as well as theoretical considerations.

   Design of Switched Reluctance Motor/Generator Systems using the Saber™ Simulator
By P.C. Kjaer; G. White; T.J.E. Miller [View]
[Download]

Abstract: This paper describes what may be considered to be the first truly holistic approach to the design of Switched Reluctance (SR) based systems. Motor and system design/analysis are two different things, and attempting to integrate them into the same program results in a compromised total solution; i.e., it is either strongly motor design oriented and weak on the system aspects or vice-versa. Implementation on the Saber™ general purpose simulator offers flexibility in redressing this imbalance, demonstrated through the design of both SR actuator and SR generator systems. The contents will be of interest to SR motor and system designer alike, with the latter being the real intended beneficiary.

   OPERATION OF A HIGH-PULSE AC/DC CONVERTOR AS A VAR COMPENSATOR
By R.D. Brough; J. Arrillaga; R.M. Duke [View]
[Download]

Abstract: Based on the ability of the ac/dc convertor to absorb controllable reactive power an alternative to the thyristor controlled reactor is proposed. A twelve-pulse naturally commutated convertor configuration is modified, using the concept of dc ripple reinjection, to achieve 36-pulse operation, thus removing the need for ac filters. The EMTDC-PSCAD program is used to compare the dynamic performance of this VAR compensator with that of the 12-pulse thyristor controlled reactor.

   THREE PHASE LINE CONVERTER WITH OPTIMISING INFLUENCE ON POWER SYSTEM
By M. Nowak; R. Barlik; P. Grochal [View]
[Download]

Abstract: The paper proposes options of control system suitable not only for DC link power control of line PWM rectifier with current output but also for reduction of line current and voltage distortions caused by additional closely installed conventional diode or thyristor converters. The main feature of the described ideas investigated with use of complex simulations is use is use of input condensers voltage feed-backs for line voltage and current wave-form improvement.

   A UNIFIED POWER FLOW CONTROLLER USING SPACE VECTOR MODULATION CONTROL
By R. Yacamini; D. Paschoareli [View]
[Download]

Abstract: The Unified Power Flow Controller (UPFC) has been presented as a concept which provides real time control of voltage, impedance and phase-angle (or any combination thereof) for power flow control and damping oscillations in power systems. It uses two voltage sourced inverters whose GTO switching periods are determined by a pulse-width modulation strategy. This paper presents a PWM method called Space Vector Modulation (SVM) which uses d-q axis components of the instantaneous voltage vector to calculate the switching instants of the relevant switches. Computator simulations have been carried out to show the performance of SVM as a controller for the UPFC. The method used to control the converter output voltages in order to control the power flow is shown to be effective and computationally straightforward.

   MICROPROCESSOR-BASED CONTROL SYSTEM FOR THE CONTROL OF ELECTRICAL MACHINES AND PROCESSES
By N. Peric; S. Marijan; M. Kajari [View]
[Download]

Abstract: The microprocessor system for the control of medium and high power electrical machines and complex processes is presented. Control functions are implemented by means of a user-oriented programming language based on block diagrams. As an application example the control system for the excitation of synchronous generators is described.

   COMPARATIVE STUDY BETWEEN SIX AND TWELVE PULSE CURRENT CONVERTERS FOR SMES SYSTEMS
By I.J. Iglesias; J. Acero; A. Bautista; M. Visiers [View]
[Download]

Abstract: This paper presents the comparison between two power converter topologies to feed a superconducting coil in a SMES (Superconducting Magnet Energy Storage) system. The two converters are a 6 and a 12 pulse GTO current converters, both controlled in PWM mode with a low switching frequency. This allows a fast adjustment of both active and reactive power and a 4-quadrant (P,Q) operation. The analysis has been carried out by using EMTP (Electromagnetic Transient Program) simulation results. The comparison criteria between both topologies has been based on the following considerations: AC current line harmonics, minimum GTO on-time, superconducting coil voltage ripple, active and reactive power capabilities and transient response. Based on the results of this paper a 500 kW power converter is being constructed as a part of a 1 MJ SMES system to carry out experimental studies in network stabilization. The PWM strategy has been implemented in the converters by means of a very fast DSP, in order to compute on-line the switching angles for any modulation index.

   A NEW CONTROL STRATEGY FOR DC-LINK VOLTAGE OF A THREE-PHASE BI-DIRECTIONAL PWM RECTIFIER
By S. Kalachnikov; H. Berger [View]
[Download]

Abstract: The harmonics of the line voltage cause a voltage ripple in the PWM-rectifiers DC-link. Its negative effect can be reduced by a DC-voltage feedback filter with large time constant, which causes low performance of the DC-link voltage control. The new control strategy for DC-link voltage gives an opportunity to improve the time response for the step change in a load of the PWM-rectifiers DC-link.

EPE 1995 - 36 - Dialogue Session DS3d: Reactive Power Compensation
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1995 - Conference > EPE 1995 - 36 - Dialogue Session DS3d: Reactive Power Compensation
	[return to parent folder]

	Static VAR Compensator for 3-Phase Induction Motors By A. A. Mahfouz; O. P. Malik	[View] [Download]
Abstract: This paper describes the use of static reactive power compensation (SVC) with 3-phase induction machines to provide a unity power factor operation. The compensator consists of 3-phase pulse width modulated (PWM) voltage source inverter connected to either a self or independently controlled dc bus. The voltage source PWM inverter is connected to the induction machine as either a shunt or series type SVC. The main advantage of this scheme is that it corrects the power factor at the load end without the need to sense and calculate the associated reactive power component at the source end. The PWM technique applied here is based on space vector modulation (SVM) principle and is implemented using a 12 MHz 16-bit microcontroller 80C196KB.

	A NOVEL VARIABLE SPEED CONSTANT FREQUENCY GENERATION SYSTEM WITH VOLTAGE REGULATION By A. Mebarki; R.T. Lipczynski	[View] [Download]
Abstract: This paper investigates the design, development and implementation of a closed loop control system to regulate the voltage and frequency of a 3-phase AC generator regardless of rotor speed and load variations. This is directed towards such generators being powered by variable speed prime movers such as windmills or diesel engines. Experimental results show the validity of the proposed strategy. The system may also be controlled so as to maximise overall system efficiency.

	NOVEL ERROR TRACKING MODE AC CURRENT WAVEFORM CONTROL METHOD AND ITS AC FILTER DESIGN PROCEDURE By Masaaki Ohshima; Eisuke Masada	[View] [Download]
Abstract: The error tracking mode (ETM) control is a novel switching algorithm for the current waveform regulation in voltage source power conversion systems (PCS´s) which can generate an arbitrary current waveform and guarantees the error between the target current and the actual one to be less than an arbitrary value given beforehand. Therefore. ETM control can operate a voltage source PCS as a current amplifier. ETM control also assures the minimum continuous on and off time of main switching devices. To connect with an utility network. it is necessary for PCS´s to suppress harmonics in both current and voltage at the point of common coupling (PCC). In the worst case, voltage oscillation would occur due to the resonance of capacitance in utility networks at the switching frequency. Implementation of an ac filter to a PCS is an effective means to prevent such voltage oscillation and to reduce both voltage and current ripples. In this paper, ETM control method and its optimum ac filter design procedure are proposed and their characteristics are discussed.

	A COMPARISON STUDY ON INSERTING THYRISTOR CONTROLLED SERIES COMPENSATION IN POWER SYSTEMS By S. Maginier; S. Bacha; N. Hadjsaid; R. Feuillet	[View] [Download]
Abstract: This paper presents two ditferent methods dealing with the insertion of Thyristor Controlled Series Compensation (TCSC) in power systems. Both methods work with time domain simulation. This is in order to study dynamic and steady state performances of TCSC. The first method is based on the well known Bergeron's method and the second one on the averaged model. Comparison between these methods are achieved and shown in this paper. The advantage and the drawback of each method is clearly pointed out.

	ITERATIVE HARMONIC SIMULATION OF A THYRISTOR CONTROLLED REACTOR AND A POWER TRANSMISSION SYSTEM By J. Arrillaga; J. GonzaIez; J. Cidras	[View] [Download]
Abstract: This paper describes an iterative algorithm (IHA) developed to study the harmonic interaction that exist between TCR (thyristor Controlled Reactor) compensators and the Transmission System. The generation of non characteristic triplen and even harmonics and their propagation along the line are accurately predicted by the lHA algorithm.

	HARMONIC TRANSFER IN HVDC SYSTEMS UNDER UNBALANCED CONDITIONS By Kadry Sadek; Marcos Pereira	[View] [Download]
Abstract: This paper presents a method developed to calculate the harmonic interactions between AC and DC side, with relatively simple formulas and tables. Considerations are made about the transfer of harmonics between AC/DC converters.

	Optimisation of the Number of Levels in a Multi-Level Advanced Static Var Compensator By D. Scheidecker; S.B. Tennakoon	[View] [Download]
Abstract: An investigation of the technical and economic merits of an N-Level Advanced Static Var Compensator (ASVC) was made. A general analysis of the multi-level ASVC was carried out and performance indices were determined for levels ranging from 3 to 14. Special interest was given to harmonic performance based on a selective harmonic elimination strategy, device utilisation and economic considerations. As the number of levels is increased more harmonics can be eliminated, but the complexity and the expense of the convertor is increased. The device and convertor utilisation considerations show that a high number of levels is not economic and a good compromise is the interconnection of phase shifted 6-level bridge convertors.

	CONTROL OF STATIC VAR COMPENSATOR FOR OPTIMAL FLICKER REDUCTION By G. De Préville; O. Lapierre; G. Bornard	[View] [Download]
Abstract: This paper describes a 51MVAR Static Var Compensator (Fixed Capacitors / Thyristors Controlled Reactors: FC/TCR) for Arc Furnaces connected to 11kV network in Egypt, to reduce voltage variations on bus line. We present a new control based on internal model control concept for high performance dynamic compensation of flicker. The electronic control is based on Fully Digital Processor System (FDPS). We also describe the power sections with up to date modular technology including optical firing system and thyristors monitoring system to monitor good health of thyristors. Comments on simulations and results conclude this paper.

	A PRACTICAL APPROACH TO HARMONIC CURRENT COMPENSATION BY A SINGLE·PHASE ACTIVE FILTER By M. Machmoum; N. Bruyant; S. Siala; R. Le Doeuff	[View] [Download]
Abstract: This paper deals with simultaneous compensation of harmonic currents and fundamental reactive power by a voltage single-phase active filter. A simple method which allows to separate the fundamental component of load current into its harmonic components is proposed. The modelling of the active filter parameters, the regulation of the harmonic currents and the capacitor dc voltage are also discussed. Experimental results of the system steady-state and transient performances, and the ability to reduce the distorsion due to the current harmonic components are presented.

	REAL-TIME SIMULATOR MODEL OF AN ADVANCED STATIC VAR COMPENSATOR By M.M. de Oliveira; A. Ekstrom	[View] [Download]
Abstract: The paper describes a scaled model of an Advanced Static Var Compensator or Static Condenser for realtime simulation studies. The Advanced Static Var Compensator is composed of two Thyristor Switched Capacitors and a twelve-pulse forced-commutated Voltage-Source Converter. Similarities and special characteristics of the adopted control system compared to a conventional Static Var Compensator are discussed. Results from the model at both symmetrical and non-symmetrical operation under transient conditions are reported.

	NEW STRATEGY FOR NON-ACTIVE POWER COMPENSATION By W. Koczara; R. Teofilak; M. Rukat; L. Grzesiak	[View] [Download]
Abstract: This paper takes into consideration a novel harmonic compensation method. The method bases on auxiliary Active Harmonic Filter, that is added to an Input Converter. The aim of the Input Converter is to compensate reactive power in the supply line with relatively low switching frequency. On the other hand the Active Harmonic Filter enables improving the shape of the current taken from the supply line. It is designed for much lower power rating and operates with higher switching frequency. Simulation results and laboratory tests are presented in the paper as well as theoretical considerations.

	Design of Switched Reluctance Motor/Generator Systems using the Saber™ Simulator By P.C. Kjaer; G. White; T.J.E. Miller	[View] [Download]
Abstract: This paper describes what may be considered to be the first truly holistic approach to the design of Switched Reluctance (SR) based systems. Motor and system design/analysis are two different things, and attempting to integrate them into the same program results in a compromised total solution; i.e., it is either strongly motor design oriented and weak on the system aspects or vice-versa. Implementation on the Saber™ general purpose simulator offers flexibility in redressing this imbalance, demonstrated through the design of both SR actuator and SR generator systems. The contents will be of interest to SR motor and system designer alike, with the latter being the real intended beneficiary.

	OPERATION OF A HIGH-PULSE AC/DC CONVERTOR AS A VAR COMPENSATOR By R.D. Brough; J. Arrillaga; R.M. Duke	[View] [Download]
Abstract: Based on the ability of the ac/dc convertor to absorb controllable reactive power an alternative to the thyristor controlled reactor is proposed. A twelve-pulse naturally commutated convertor configuration is modified, using the concept of dc ripple reinjection, to achieve 36-pulse operation, thus removing the need for ac filters. The EMTDC-PSCAD program is used to compare the dynamic performance of this VAR compensator with that of the 12-pulse thyristor controlled reactor.

	THREE PHASE LINE CONVERTER WITH OPTIMISING INFLUENCE ON POWER SYSTEM By M. Nowak; R. Barlik; P. Grochal	[View] [Download]
Abstract: The paper proposes options of control system suitable not only for DC link power control of line PWM rectifier with current output but also for reduction of line current and voltage distortions caused by additional closely installed conventional diode or thyristor converters. The main feature of the described ideas investigated with use of complex simulations is use is use of input condensers voltage feed-backs for line voltage and current wave-form improvement.

	A UNIFIED POWER FLOW CONTROLLER USING SPACE VECTOR MODULATION CONTROL By R. Yacamini; D. Paschoareli	[View] [Download]
Abstract: The Unified Power Flow Controller (UPFC) has been presented as a concept which provides real time control of voltage, impedance and phase-angle (or any combination thereof) for power flow control and damping oscillations in power systems. It uses two voltage sourced inverters whose GTO switching periods are determined by a pulse-width modulation strategy. This paper presents a PWM method called Space Vector Modulation (SVM) which uses d-q axis components of the instantaneous voltage vector to calculate the switching instants of the relevant switches. Computator simulations have been carried out to show the performance of SVM as a controller for the UPFC. The method used to control the converter output voltages in order to control the power flow is shown to be effective and computationally straightforward.

	MICROPROCESSOR-BASED CONTROL SYSTEM FOR THE CONTROL OF ELECTRICAL MACHINES AND PROCESSES By N. Peric; S. Marijan; M. Kajari	[View] [Download]
Abstract: The microprocessor system for the control of medium and high power electrical machines and complex processes is presented. Control functions are implemented by means of a user-oriented programming language based on block diagrams. As an application example the control system for the excitation of synchronous generators is described.

	COMPARATIVE STUDY BETWEEN SIX AND TWELVE PULSE CURRENT CONVERTERS FOR SMES SYSTEMS By I.J. Iglesias; J. Acero; A. Bautista; M. Visiers	[View] [Download]
Abstract: This paper presents the comparison between two power converter topologies to feed a superconducting coil in a SMES (Superconducting Magnet Energy Storage) system. The two converters are a 6 and a 12 pulse GTO current converters, both controlled in PWM mode with a low switching frequency. This allows a fast adjustment of both active and reactive power and a 4-quadrant (P,Q) operation. The analysis has been carried out by using EMTP (Electromagnetic Transient Program) simulation results. The comparison criteria between both topologies has been based on the following considerations: AC current line harmonics, minimum GTO on-time, superconducting coil voltage ripple, active and reactive power capabilities and transient response. Based on the results of this paper a 500 kW power converter is being constructed as a part of a 1 MJ SMES system to carry out experimental studies in network stabilization. The PWM strategy has been implemented in the converters by means of a very fast DSP, in order to compute on-line the switching angles for any modulation index.

	A NEW CONTROL STRATEGY FOR DC-LINK VOLTAGE OF A THREE-PHASE BI-DIRECTIONAL PWM RECTIFIER By S. Kalachnikov; H. Berger	[View] [Download]
Abstract: The harmonics of the line voltage cause a voltage ripple in the PWM-rectifiers DC-link. Its negative effect can be reduced by a DC-voltage feedback filter with large time constant, which causes low performance of the DC-link voltage control. The new control strategy for DC-link voltage gives an opportunity to improve the time response for the step change in a load of the PWM-rectifiers DC-link.