EPE Association: EPE 2007 - Subtopic 14-5 - DS: HVDC, FACTS, Active, passive and combined filtering

EPE 2007 - Subtopic 14-5 - DS: HVDC, FACTS, Active, passive and combined filtering
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 14: 'Transmission and distribution of electrical energy' > EPE 2007 - Subtopic 14-5 - DS: HVDC, FACTS, Active, passive and combined filtering

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   A Low Voltage Dynamic Voltage Restorer with Self-Charging Capability
By MACHMOUM Mohamed; SHAFIEE KHOOR Mohsen [View]
[Download]

Abstract: In this paper a three phase low voltage dynamic voltage restorer (DVR) with a capacitor DC-link will be presented. A proper charging strategy is chosen for charging the DC bus by DVR power converter. The proposed DVR is capable of removing the voltage harmonics (up to 23rd order) and short terms voltage dips very quickly. Voltage identification method and control strategy will be presented and the dynamical and steady state responses of the DVR for non-linear capacitive and inductive loads will be presented and discussed in detail.

   A novel hysteresis voltage control for Series Active Power filter
By NADIA Ait Ahmed; FATIHA Mekri; MOHAMED Machmoum; BENYOUNES Mazari [View]
[Download]

Abstract: In this paper a novel hysteresis voltage control for a series active power filter is proposed to improve the Power Quality (PQ), which is one of the most important issues of modern electrical distribution. The active filter controller is based on a new control strategy related to hysteresis band voltage control method, where the band is modulated with the system parameters to maintain the modulation frequency nearly constant. The new hystersis voltage control is presented and tested. This method has a good voltage tracking accuracy and a nearly constant switching frequency. Therefore, it is efficient and safe in operation. Simulation results show that this voltage control method improves the series active power filter performances noticeably. The determination of voltage references for series active power filter is based on a robust three-phase digital locked loop (PLL) system using RST regulator.

   Active Power Filtering by A Flying-Capacitor Multilevel Inverter with Capacitor Voltage Balance
By HU Junfei; ZHANG Li [View]
[Download]

Abstract: The abstract is not available.

   Direct Power Control of Shunt Active Filter
By GAUBERT Jean-Paul; CHAOUI Abdelmadjid [View]
[Download]

Abstract: This paper presents a new control method entitled direct power control (DPC) for shunt active power filtering, which is applied to eliminate line current harmonics and compensate reactive power. Its main goal is to rebuild active and reactive powers to be compared to references values using hysteresis control. The outputs of hysteresis controllers associated with a switching table, control the instantaneous active and reactive power by selecting the optimum switching state of the voltage source inverter (VSI). A theoretical analysis with a complete simulation of the system and experimental results are presented to prove the excellent performance of the proposed technique.

   Experimental Studies on Fault Current Limiter by Voltage Source Inverter with Line Voltage Harmonics Compensation
By FUJIMURA Yuki; HOJO Masahide; FUNABASHI Toshihisa; OHNISHI Tokuo [View]
[Download]

Abstract: Recently, many distributed generators have been connected to a power system. These may cause a large current if some system fault occurs in the power system, therefore a short-circuit capacity of the power system should be carefully considered. However, the short-circuit capacity also depends on a line impedance. A large line impedance will suppress the increase of short-circuit capacity, but it will cause the other difficulties about a line voltage harmonics. Increase of nonlinear loads such as diode rectifier circuits results in the line voltage distortion on an electric power distribution line. In the circumstances, a useful apparatus which can both reduce the short-circuit capacity and suppress the line voltage distortions is expected to provide a solution against these difficulties. Authors have developed a converter-based FCL as an advanced power system protection apparatus. The FCL consists of a series inductor and a self-commutated voltage source inverter connected in series with a line by a coupling transformer. It utilizes a variable reactance which is realized by suitable operation of the series inverter. During a fault in a power system, the series inverter is activated as an additional inductor to reduce the fault current best. But in a standby mode, it behaves like a capacitor for compensating a voltage drop across the inserted series inductor. This paper proposes that the FCL compensates line voltage harmonics as well as the voltage drop across the series inductor in the standby mode. The operating characteristics and effectiveness of the FCL are confirmed by experimental studies with a laboratory scale model.

   FACTS for dynamic load balancing and voltage support in rail traction
By GRÃœNBAUM Rolf [View]
[Download]

Abstract: With increasing focus on economical as well as environmentally friendly means for mass transit, rail transport is gaining renewed momentum in many parts of the world. This means investing in novel rail infrastructure as well as upgrading and electrifying existing facilities. The TEN (Trans-European Network) program within the European Union is but one current example of the importance attributed to more and better mass transit all over the world. The feeding of heavy rolling stock from AC grids will in many cases cause unacceptable voltage drops as well as unsymmetry between phases of the feeding grid. A traditional way to improve the situation would be to build additional power transmission lines and/or step up the feeding voltage to a higher level. This, however, may be undesirable or even impossible, for cost reasons as well as for environmental reasons. FACTS devices offer means of remedy within the existing feeding grid, restoring grid symmetry as well as voltage stability, and also mitigating harmonic distortion emanating from rolling stock. FACTS devices such as SVC (Static Var Compensator) and STATCOM (Static Compensator) are well proven and commercially available today. The paper treats dynamic load balancing of grids supplying power to rail transport, as well as dynamic voltage support and harmonic mitigation, by means of SVC as well as STATCOM.

   Fast connection /reconnection of the VSC to the power network
By KREBS Uwe; RASIC Andreja; HEROLD Gerhard [View]
[Download]

Abstract: The problem of the connection of the voltage source converters to the network occurs when the converter transformer is energized from the converter side. This paper deals with the main problems of the transformer energizing, and proposes the procedure for the inrush elimination, simultaneously minimizing the connection period. When a transformer is connected to a circuit, under certain conditions magnetizing inrush currents may arise up to ten times the full load current of the transformer. These currents contain a large amount of harmonic components and cause some relays to trip out. When the transformer is energized with the power electronic devices, these currents could destroy them as well as the DC capacitor. In this paper, the compensation of the magnetizing inrush current using a PWM inverter was discussed. The magnetic condition of the transformer is estimated and the PWM inverter generates compensating voltage. Direct flux controllers are used for the fast response. The validity of analytically obtained results is investigated by using the process simulation. In addition, hardware implementation for the compensator is accomplished to verify the simulation results.

   Feasible series compensation applications using Magnetic Energy Recovery Switch (MERS)
By SHIMADA Ryuichi; WIIK Jan; ISOBE Takanori; USUKI Kazuhiro; WIJAYA F Danang; ARAI Nobuyuki; TAKAKU Taku [View]
[Download]

Abstract: Different series compensation applications using the Magnetic Energy Recovery Switch are reviewed. The Magnetic Energy Recovery Switch is a variable series compensation device characterized by simple configuration and control as well as a large operating range. Three different applications areas are introduced; Load control, generator power capability improvements and series compensation in transmission systems. Load control application seems promising for cases where control of the frequency is not a necessity, such as for fluorescent lamps. By using MERS in series with permanent magnet generators can the output power capability of the generator be increased. At the high power end, MERS is discussed for use as a series compensator in transmission systems, where the power flow can be controlled and increased. In summary, the paper suggests a wider use of series compensation in electrical systems.

   Industrial D-STATCOM chain link modeling and control
By THIERRY Jean-Luc; LEE-KWET-SUN Evelyne; BENCHAIB Abdelkrim; DE-PREVILLE Guillaume [View]
[Download]

Abstract: This paper presents a new scheme of control for D-STATCOM chain link system. The controller based on nonlinear model, is derived using time basis linearization method. In fact, the considered system can be represented as an interconnection of two subsystems with different dynamics. Simulation and experimental results will show the effectiveness of the proposed method.

   On the Simulation of Valve Reactors
By FISCHER Werner; LE TRUNG Arien [View]
[Download]

Abstract: A model of saturable valve reactor is investigated. Starting from the equivalent circuit diagram of a transformer, the relative differential permeability of the strip wound cores and the coefficient of coupling are identified as basic parameters. These parameters are determined with the help of impulse voltage measurements for a certain reactor with Silectron strip wound cores. Thereby new results are gained concerning the dynamic magnetization behavior of these cores. Simulation yields good agreement with measurement for impulse magnetization.

   Parallel Operation of Thyristor- and IGBT-based HVDC
By PETTER Thorsten; ORLIK Bernd; RAFFEL Holger [View]
[Download]

Abstract: The future for wind power generation in Germany is the offshore wind energy. The preferred concept for power transmission over long distances from the offshore plant to the mainland is the High Voltage Direct Current (HVDC) power transmission. In this paper new concepts for power transmission based on HVDC are presented, with a parallel operation of thyristor- and IGBT-HVDC. There has been done some work on the research of parallel operating converter in the University of Bremen.

   Performance Enhancement and Comparison of Discrete Time Current Regulators for Parallel Active Filters
By HAVA Ahmet; Ã–ZKAYA Hasan; ŞENTÃœRK Osman SelÃ§uk [View]
[Download]

Abstract: Discrete time linear and hysteresis current regulators (CR) for three-phase parallel active filters (PAF) are reviewed and evaluated. A novel discrete time hysteresis current regulation method with current oversampling and flexible PWM release capability, DHCR3, which has superior overall performance and simple implementation (no additional hardware) is proposed. Switching ripple filters (SRF) suitable for each CR type are designed. A DSP controlled PAF is designed and built for a three-phase 10 kW diode rectifier load. The CR and PAF performances are verified by means of theory, simulations, and experiments and strong correlation is obtained. The study shows that of various CRs, the synchronous frame resonant filter CR and DHCR3 with appropriate SRF types perform satisfactorily and the latter has much lower implementation complexity and reduced switching losses.

   Selective Harmonic Current Mitigation with Shunt Active Power Filter
By HANSEN Steffan; LASCU Cristian; ASIMINOAEI Lucian; BLAABJERG Frede [View]
[Download]

Abstract: The paper presents three methods of selective harmonic compensation with shunt Active Power Filters in different reference frames: harmonic dq-frame, stationary frame and fundamental dq-frame; and shows that the last two methods are derived from the first one. By analyzing their advantages and drawbacks, the paper shows that the last two methods have a more compact mathematical representation which may extend to straightforward DSP implementation. However, the first method, i.e. selective compensation in harmonic dq-frame, is more flexible and allows a better tuning and adjustment, which is of a great importance in practice. For experimental tests only the selective harmonic control in fundamental dq-frame is presented, to demonstrate the selectiveness harmonic current compensation. The experimental results are performed in laboratory conditions on a 7 kVA Active Filter prototype, indicating a reduction in current THDi factor from the existing 27 \% to 2 \%.

   STATCOM Operation under Single Line-Ground System Faults with Magnetic Saturation in Series Connected Transformers based 48-pulse Voltage-Source Convert
By BHATTACHARYA Subhashish; XI Zhengping [View]
[Download]

Abstract: In this paper, we investigate an "emergency PWM" method to prevent over-currents in VSC based STATCOM and control transformer magnetic saturation under single line-ground (SLG) power system faults. The 100MVA 48-pulse VSC topology is based on four series connected transformers on the primary side and each transformer secondary is connected to a 3 phase, 3-level Neutral Point Connected (NPC) VSC, with a common dc bus. A practical issue of impact of slightly different saturation (B-H) characteristics of series connected transformers, on VSC performance is investigated for SLG faults in the power system. The detailed simulation results for a 48-pulse GTO thyristor based VSC 100 MVA STATCOM connected to a 2-bus power system under SLG system faults validate that the proposed "emergency PWM" enables STATCOM operation under transformer saturation without over-currents in the GTO devices. The proposed "emergency PWM" strategy prevents STATCOM tripping under SLG power system faults.

   Three-level Converter based Active Filter for harmonic compensation of 4 MW Induction Furnace
By AAMANTHRA KELOTH Unnikrishnan; JOSEPH Aby; JOSHI TG Subhash; V Ramanarayanan [View]
[Download]

Abstract: The paper explains the power quality study conducted in a 4MW mini steel plant, having fault level of 250MVA, to investigate the critical electrical problems caused by the harmonics and the development of a STATCOM as a solution for harmonic mitigation. A 500kVAR STATCOM is realized with a current controlled three level voltage source converter (VSC). The hardware configuration and the control strategy have been dealt in detail. Site installation and experimental results demonstrating STATCOM's performance are also presented.

EPE 2007 - Subtopic 14-5 - DS: HVDC, FACTS, Active, passive and combined filtering
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 14: 'Transmission and distribution of electrical energy' > EPE 2007 - Subtopic 14-5 - DS: HVDC, FACTS, Active, passive and combined filtering
	[return to parent folder]

	A Low Voltage Dynamic Voltage Restorer with Self-Charging Capability By MACHMOUM Mohamed; SHAFIEE KHOOR Mohsen	[View] [Download]
Abstract: In this paper a three phase low voltage dynamic voltage restorer (DVR) with a capacitor DC-link will be presented. A proper charging strategy is chosen for charging the DC bus by DVR power converter. The proposed DVR is capable of removing the voltage harmonics (up to 23rd order) and short terms voltage dips very quickly. Voltage identification method and control strategy will be presented and the dynamical and steady state responses of the DVR for non-linear capacitive and inductive loads will be presented and discussed in detail.

	A novel hysteresis voltage control for Series Active Power filter By NADIA Ait Ahmed; FATIHA Mekri; MOHAMED Machmoum; BENYOUNES Mazari	[View] [Download]
Abstract: In this paper a novel hysteresis voltage control for a series active power filter is proposed to improve the Power Quality (PQ), which is one of the most important issues of modern electrical distribution. The active filter controller is based on a new control strategy related to hysteresis band voltage control method, where the band is modulated with the system parameters to maintain the modulation frequency nearly constant. The new hystersis voltage control is presented and tested. This method has a good voltage tracking accuracy and a nearly constant switching frequency. Therefore, it is efficient and safe in operation. Simulation results show that this voltage control method improves the series active power filter performances noticeably. The determination of voltage references for series active power filter is based on a robust three-phase digital locked loop (PLL) system using RST regulator.

	Active Power Filtering by A Flying-Capacitor Multilevel Inverter with Capacitor Voltage Balance By HU Junfei; ZHANG Li	[View] [Download]
Abstract: The abstract is not available.

	Direct Power Control of Shunt Active Filter By GAUBERT Jean-Paul; CHAOUI Abdelmadjid	[View] [Download]
Abstract: This paper presents a new control method entitled direct power control (DPC) for shunt active power filtering, which is applied to eliminate line current harmonics and compensate reactive power. Its main goal is to rebuild active and reactive powers to be compared to references values using hysteresis control. The outputs of hysteresis controllers associated with a switching table, control the instantaneous active and reactive power by selecting the optimum switching state of the voltage source inverter (VSI). A theoretical analysis with a complete simulation of the system and experimental results are presented to prove the excellent performance of the proposed technique.

	Experimental Studies on Fault Current Limiter by Voltage Source Inverter with Line Voltage Harmonics Compensation By FUJIMURA Yuki; HOJO Masahide; FUNABASHI Toshihisa; OHNISHI Tokuo	[View] [Download]
Abstract: Recently, many distributed generators have been connected to a power system. These may cause a large current if some system fault occurs in the power system, therefore a short-circuit capacity of the power system should be carefully considered. However, the short-circuit capacity also depends on a line impedance. A large line impedance will suppress the increase of short-circuit capacity, but it will cause the other difficulties about a line voltage harmonics. Increase of nonlinear loads such as diode rectifier circuits results in the line voltage distortion on an electric power distribution line. In the circumstances, a useful apparatus which can both reduce the short-circuit capacity and suppress the line voltage distortions is expected to provide a solution against these difficulties. Authors have developed a converter-based FCL as an advanced power system protection apparatus. The FCL consists of a series inductor and a self-commutated voltage source inverter connected in series with a line by a coupling transformer. It utilizes a variable reactance which is realized by suitable operation of the series inverter. During a fault in a power system, the series inverter is activated as an additional inductor to reduce the fault current best. But in a standby mode, it behaves like a capacitor for compensating a voltage drop across the inserted series inductor. This paper proposes that the FCL compensates line voltage harmonics as well as the voltage drop across the series inductor in the standby mode. The operating characteristics and effectiveness of the FCL are confirmed by experimental studies with a laboratory scale model.

	FACTS for dynamic load balancing and voltage support in rail traction By GRÃœNBAUM Rolf	[View] [Download]
Abstract: With increasing focus on economical as well as environmentally friendly means for mass transit, rail transport is gaining renewed momentum in many parts of the world. This means investing in novel rail infrastructure as well as upgrading and electrifying existing facilities. The TEN (Trans-European Network) program within the European Union is but one current example of the importance attributed to more and better mass transit all over the world. The feeding of heavy rolling stock from AC grids will in many cases cause unacceptable voltage drops as well as unsymmetry between phases of the feeding grid. A traditional way to improve the situation would be to build additional power transmission lines and/or step up the feeding voltage to a higher level. This, however, may be undesirable or even impossible, for cost reasons as well as for environmental reasons. FACTS devices offer means of remedy within the existing feeding grid, restoring grid symmetry as well as voltage stability, and also mitigating harmonic distortion emanating from rolling stock. FACTS devices such as SVC (Static Var Compensator) and STATCOM (Static Compensator) are well proven and commercially available today. The paper treats dynamic load balancing of grids supplying power to rail transport, as well as dynamic voltage support and harmonic mitigation, by means of SVC as well as STATCOM.

	Fast connection /reconnection of the VSC to the power network By KREBS Uwe; RASIC Andreja; HEROLD Gerhard	[View] [Download]
Abstract: The problem of the connection of the voltage source converters to the network occurs when the converter transformer is energized from the converter side. This paper deals with the main problems of the transformer energizing, and proposes the procedure for the inrush elimination, simultaneously minimizing the connection period. When a transformer is connected to a circuit, under certain conditions magnetizing inrush currents may arise up to ten times the full load current of the transformer. These currents contain a large amount of harmonic components and cause some relays to trip out. When the transformer is energized with the power electronic devices, these currents could destroy them as well as the DC capacitor. In this paper, the compensation of the magnetizing inrush current using a PWM inverter was discussed. The magnetic condition of the transformer is estimated and the PWM inverter generates compensating voltage. Direct flux controllers are used for the fast response. The validity of analytically obtained results is investigated by using the process simulation. In addition, hardware implementation for the compensator is accomplished to verify the simulation results.

	Feasible series compensation applications using Magnetic Energy Recovery Switch (MERS) By SHIMADA Ryuichi; WIIK Jan; ISOBE Takanori; USUKI Kazuhiro; WIJAYA F Danang; ARAI Nobuyuki; TAKAKU Taku	[View] [Download]
Abstract: Different series compensation applications using the Magnetic Energy Recovery Switch are reviewed. The Magnetic Energy Recovery Switch is a variable series compensation device characterized by simple configuration and control as well as a large operating range. Three different applications areas are introduced; Load control, generator power capability improvements and series compensation in transmission systems. Load control application seems promising for cases where control of the frequency is not a necessity, such as for fluorescent lamps. By using MERS in series with permanent magnet generators can the output power capability of the generator be increased. At the high power end, MERS is discussed for use as a series compensator in transmission systems, where the power flow can be controlled and increased. In summary, the paper suggests a wider use of series compensation in electrical systems.

	Industrial D-STATCOM chain link modeling and control By THIERRY Jean-Luc; LEE-KWET-SUN Evelyne; BENCHAIB Abdelkrim; DE-PREVILLE Guillaume	[View] [Download]
Abstract: This paper presents a new scheme of control for D-STATCOM chain link system. The controller based on nonlinear model, is derived using time basis linearization method. In fact, the considered system can be represented as an interconnection of two subsystems with different dynamics. Simulation and experimental results will show the effectiveness of the proposed method.

	On the Simulation of Valve Reactors By FISCHER Werner; LE TRUNG Arien	[View] [Download]
Abstract: A model of saturable valve reactor is investigated. Starting from the equivalent circuit diagram of a transformer, the relative differential permeability of the strip wound cores and the coefficient of coupling are identified as basic parameters. These parameters are determined with the help of impulse voltage measurements for a certain reactor with Silectron strip wound cores. Thereby new results are gained concerning the dynamic magnetization behavior of these cores. Simulation yields good agreement with measurement for impulse magnetization.

	Parallel Operation of Thyristor- and IGBT-based HVDC By PETTER Thorsten; ORLIK Bernd; RAFFEL Holger	[View] [Download]
Abstract: The future for wind power generation in Germany is the offshore wind energy. The preferred concept for power transmission over long distances from the offshore plant to the mainland is the High Voltage Direct Current (HVDC) power transmission. In this paper new concepts for power transmission based on HVDC are presented, with a parallel operation of thyristor- and IGBT-HVDC. There has been done some work on the research of parallel operating converter in the University of Bremen.

	Performance Enhancement and Comparison of Discrete Time Current Regulators for Parallel Active Filters By HAVA Ahmet; Ã–ZKAYA Hasan; ŞENTÃœRK Osman SelÃ§uk	[View] [Download]
Abstract: Discrete time linear and hysteresis current regulators (CR) for three-phase parallel active filters (PAF) are reviewed and evaluated. A novel discrete time hysteresis current regulation method with current oversampling and flexible PWM release capability, DHCR3, which has superior overall performance and simple implementation (no additional hardware) is proposed. Switching ripple filters (SRF) suitable for each CR type are designed. A DSP controlled PAF is designed and built for a three-phase 10 kW diode rectifier load. The CR and PAF performances are verified by means of theory, simulations, and experiments and strong correlation is obtained. The study shows that of various CRs, the synchronous frame resonant filter CR and DHCR3 with appropriate SRF types perform satisfactorily and the latter has much lower implementation complexity and reduced switching losses.

	Selective Harmonic Current Mitigation with Shunt Active Power Filter By HANSEN Steffan; LASCU Cristian; ASIMINOAEI Lucian; BLAABJERG Frede	[View] [Download]
Abstract: The paper presents three methods of selective harmonic compensation with shunt Active Power Filters in different reference frames: harmonic dq-frame, stationary frame and fundamental dq-frame; and shows that the last two methods are derived from the first one. By analyzing their advantages and drawbacks, the paper shows that the last two methods have a more compact mathematical representation which may extend to straightforward DSP implementation. However, the first method, i.e. selective compensation in harmonic dq-frame, is more flexible and allows a better tuning and adjustment, which is of a great importance in practice. For experimental tests only the selective harmonic control in fundamental dq-frame is presented, to demonstrate the selectiveness harmonic current compensation. The experimental results are performed in laboratory conditions on a 7 kVA Active Filter prototype, indicating a reduction in current THDi factor from the existing 27 \% to 2 \%.

	STATCOM Operation under Single Line-Ground System Faults with Magnetic Saturation in Series Connected Transformers based 48-pulse Voltage-Source Convert By BHATTACHARYA Subhashish; XI Zhengping	[View] [Download]
Abstract: In this paper, we investigate an "emergency PWM" method to prevent over-currents in VSC based STATCOM and control transformer magnetic saturation under single line-ground (SLG) power system faults. The 100MVA 48-pulse VSC topology is based on four series connected transformers on the primary side and each transformer secondary is connected to a 3 phase, 3-level Neutral Point Connected (NPC) VSC, with a common dc bus. A practical issue of impact of slightly different saturation (B-H) characteristics of series connected transformers, on VSC performance is investigated for SLG faults in the power system. The detailed simulation results for a 48-pulse GTO thyristor based VSC 100 MVA STATCOM connected to a 2-bus power system under SLG system faults validate that the proposed "emergency PWM" enables STATCOM operation under transformer saturation without over-currents in the GTO devices. The proposed "emergency PWM" strategy prevents STATCOM tripping under SLG power system faults.

	Three-level Converter based Active Filter for harmonic compensation of 4 MW Induction Furnace By AAMANTHRA KELOTH Unnikrishnan; JOSEPH Aby; JOSHI TG Subhash; V Ramanarayanan	[View] [Download]
Abstract: The paper explains the power quality study conducted in a 4MW mini steel plant, having fault level of 250MVA, to investigate the critical electrical problems caused by the harmonics and the development of a STATCOM as a solution for harmonic mitigation. A 500kVAR STATCOM is realized with a current controlled three level voltage source converter (VSC). The hardware configuration and the control strategy have been dealt in detail. Site installation and experimental results demonstrating STATCOM's performance are also presented.