EPE Association: EPE 1997 – 73: Dialogue Session DS8a-2: FACTS 2

EPE 1997 – 73: Dialogue Session DS8a-2: FACTS 2
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 73: Dialogue Session DS8a-2: FACTS 2

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   PSEUDO-RESONANT COMPENSATOR FOR FULL CONTROL OF REAL AND REACTIVE POWER
By Pramod Parihar; George G. Karady [View]
[Download]

Abstract: This paper presents a new power electronics circuit that can be used for real and reactive power regulation in power systems. The circuit injects a sinusoidal current at variable phase and magnitude into the power system. The proposed high-frequency high-power resonant system is soft switched in most operating modes, less lossy, generates lower EMI, and has a faster response time than the currently available compensation schemes. The paper describes the concept of current injection for power quality control in power systems, verification using simulation studies, and proof of principle hardware implementation.

   POWER MODULATION CAPABILITY OF SHUNT AND SERIES COMPENSATORS AND PHASE SHIFTERS
By D. A. Pastos; G. B. Giannakopoulos; N. A. Vovos [View]
[Download]

Abstract: In this paper the power flow modulation capability of controllable shunt and series compensators and phase shifters is investigated and compared. Based on small perturbation analysis and using the complex power injection models of these devices, the linearized model of the system is obtained which is properly used to quantitatively calculate this capability. Extended investigations on a test system regarding the dependence of the power flow modulation capability on basic parameters, as the compensator location, the load location and the load characteristics are presented.

   STATIC VAR COMPENSATOR FOR FLICKER REDUCTION
By B. GOLLENTZ; G. DE PREVILLE; J. L. POULIQUEN [View]
[Download]

Abstract: This paper describes a 50MVAR Static Var Compensator (Fixed Capacitors / Thyristors Controlled Reactors: FC/TCR) for Arc Furnaces connected to 11kV network, 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. Then we present then the comparison between the simulations made for an optimisation of the control and the result obtained on site.

   SOLID-STATE POWER FACTOR CORRECTION USING VOLTAGE SOURCE INVERTER SELF-CONTROLLED DC BUS
By A. A. MANSOUR; O. A. MAHGOUB; A. M. ZAKI; E. E. ABU-ELZAHAB [View]
[Download]

Abstract: The VAR compensation can be achieved by several approaches. With the advances in power electronic devices, the solid-state VAR compensators (SSVCs) are proposed giving more efficient response and reliability. One of the techniques used in power factor correction is the voltage source- inverter self-controlled de bus. In this paper the performance of the system to achieve leading and lagging compensation will be studied. The analysis is based on space vector theory (d-q synchronous frame), and the simulation is performed using MATLAB. The compensation system is implemented by using three-phase inverter controlled by the microcomputer via 8-bit interface card which is designed to achieve instantaneous load compensation and make the inverter output frequency restricted with the supply frequency. The system presents good transient performance.

   ELECTRONIC TAP CHANGER FOR 10 kV DISTRIBUTION TRANSFORMER
By P. Bauer; S. W. H. de Haan; G. C. Paap [View]
[Download]

Abstract: Power supply quality is a very actual matter. Distribution transformer tap changer with the continuous operation of tap changing and control of the secondary voltage brings a remarkable improvement in power supply quality, keeping the voltage in the net constant. Theoretical study, design and practical evaluation of the electronic tap changer for a threephase 10 kV distribution power transformer are described in the paper.

   A PWM-OPERATED VOLTAGE SOURCE CONVERTER FOR FLICKER MITIGATION
By T. Larsson; A. Ekström [View]
[Download]

Abstract: Flicker has become an important power quality issue. One of the largest sources for flicker is the electric arc furnace, which due to its large time-varying load causes big voltage variations in the grid. Electric bulbs connected to this voltage produces a time-varying illumination, flicker, that is very annoying for humans. In the paper, an analysis is done on what parts of the voltage spectrum that causes the flicker. It has been found that most parts of the flicker is generated by two narrow sidebands of the voltage fundamental. This has been verified in digital simulations with an arc furnace model containing a sinusoidally varied arc resistance. To mitigate the flicker, a voltage source converter (VSC) has been connected in parallel with the arc furnace and simulated. The converter control is performed in the synchronously rotating dq-frame. Delays from measurement to realised converter current are of large importance for a well performing flicker mitigation. Measures have been taken in the control scheme to reduce the delay due to measurement filters and pulse width modulation (PWM). The flicker mitigation capability of a 60 MV A VSC is finally compared to that of a 120 MV A SVC in a case with random arc length modulation. The PST is in this specific case reduced from 3,8 down to 2,4 with the SVC and to 1,2 with the VSC.

   DSP Control of an Active Power Line Conditioning System
By J. M. Carrasco; M. Perales; B. Ruiz; E. Galvan; L. G. Franquelo; S. Gutierrez; E. G. de Mendivil [View]
[Download]

Abstract: DSP based control of an active power line conditioning system is described in this paper. The control algorithm is proposed on the basis of the instantaneous reactive power theory. This aims at excellent compensation characteristics in transient states as well as steady states. The control functions are implemented using Texas Instrument low cost starter kit including a 32 bit floating point TMS320C31 DSP-based hardware and software. It was developped an specific adquisition board to be adapted to the Texas Instrument stater kit. The controller has been tested in the laboratory with the prototype and shows excellent performance.

   MPTC: AN ECONOMICAL ALTERNATIVE TO UNIVERSAL POWER FLOW CONTROLLERS
By Ned Mohan [View]
[Download]

Abstract: It is important to have control over power transfer in interconnected power systems. This can improve stability and allow transmission lines to be loaded closer to their thermal limits than otherwise possible. It can minimize power losses by directing power to flow along its intended path. The objective of this paper is to describe a new power transfer controller called MPTC [1], which has most of the functionality of UPFC and has the potential to be much more cost-effective. This controller is based on a novel combination of proven technologies and recent advances in semiconductor devices. Application of this controller in improving power quality during voltage sag conditions is also discussed.

   APPLICATION OF THYRISTOR CONTROLLED SERIES CAPACITOR FOR DAMPING OF ELECTROMECHANICAL OSCILLATIONS
By Ole Johan Hjemas; Mojtaba Noroozian [View]
[Download]

Abstract: This paper examines the improvement of power system dynamics by use of a thyristor controlled series capacitor (TCSC). Models suitable for incorporation in dynamic simulation programs for studying angle stability are analyzed. A control strategy for damping of electromechanical power oscillations using an energy function method is derived. The achieved control law is shown to be effective both for damping of large signal and small signal disturbances and are robust with respect to loading condition, fault location and network structure. Furthermore, the control input is easily attainable from the locally measurable variables. The effectiveness of the control is demonstrated for model power systems.

EPE 1997 – 73: Dialogue Session DS8a-2: FACTS 2
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 73: Dialogue Session DS8a-2: FACTS 2
	[return to parent folder]

	PSEUDO-RESONANT COMPENSATOR FOR FULL CONTROL OF REAL AND REACTIVE POWER By Pramod Parihar; George G. Karady	[View] [Download]
Abstract: This paper presents a new power electronics circuit that can be used for real and reactive power regulation in power systems. The circuit injects a sinusoidal current at variable phase and magnitude into the power system. The proposed high-frequency high-power resonant system is soft switched in most operating modes, less lossy, generates lower EMI, and has a faster response time than the currently available compensation schemes. The paper describes the concept of current injection for power quality control in power systems, verification using simulation studies, and proof of principle hardware implementation.

	POWER MODULATION CAPABILITY OF SHUNT AND SERIES COMPENSATORS AND PHASE SHIFTERS By D. A. Pastos; G. B. Giannakopoulos; N. A. Vovos	[View] [Download]
Abstract: In this paper the power flow modulation capability of controllable shunt and series compensators and phase shifters is investigated and compared. Based on small perturbation analysis and using the complex power injection models of these devices, the linearized model of the system is obtained which is properly used to quantitatively calculate this capability. Extended investigations on a test system regarding the dependence of the power flow modulation capability on basic parameters, as the compensator location, the load location and the load characteristics are presented.

	STATIC VAR COMPENSATOR FOR FLICKER REDUCTION By B. GOLLENTZ; G. DE PREVILLE; J. L. POULIQUEN	[View] [Download]
Abstract: This paper describes a 50MVAR Static Var Compensator (Fixed Capacitors / Thyristors Controlled Reactors: FC/TCR) for Arc Furnaces connected to 11kV network, 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. Then we present then the comparison between the simulations made for an optimisation of the control and the result obtained on site.

	SOLID-STATE POWER FACTOR CORRECTION USING VOLTAGE SOURCE INVERTER SELF-CONTROLLED DC BUS By A. A. MANSOUR; O. A. MAHGOUB; A. M. ZAKI; E. E. ABU-ELZAHAB	[View] [Download]
Abstract: The VAR compensation can be achieved by several approaches. With the advances in power electronic devices, the solid-state VAR compensators (SSVCs) are proposed giving more efficient response and reliability. One of the techniques used in power factor correction is the voltage source- inverter self-controlled de bus. In this paper the performance of the system to achieve leading and lagging compensation will be studied. The analysis is based on space vector theory (d-q synchronous frame), and the simulation is performed using MATLAB. The compensation system is implemented by using three-phase inverter controlled by the microcomputer via 8-bit interface card which is designed to achieve instantaneous load compensation and make the inverter output frequency restricted with the supply frequency. The system presents good transient performance.

	ELECTRONIC TAP CHANGER FOR 10 kV DISTRIBUTION TRANSFORMER By P. Bauer; S. W. H. de Haan; G. C. Paap	[View] [Download]
Abstract: Power supply quality is a very actual matter. Distribution transformer tap changer with the continuous operation of tap changing and control of the secondary voltage brings a remarkable improvement in power supply quality, keeping the voltage in the net constant. Theoretical study, design and practical evaluation of the electronic tap changer for a threephase 10 kV distribution power transformer are described in the paper.

	A PWM-OPERATED VOLTAGE SOURCE CONVERTER FOR FLICKER MITIGATION By T. Larsson; A. Ekström	[View] [Download]
Abstract: Flicker has become an important power quality issue. One of the largest sources for flicker is the electric arc furnace, which due to its large time-varying load causes big voltage variations in the grid. Electric bulbs connected to this voltage produces a time-varying illumination, flicker, that is very annoying for humans. In the paper, an analysis is done on what parts of the voltage spectrum that causes the flicker. It has been found that most parts of the flicker is generated by two narrow sidebands of the voltage fundamental. This has been verified in digital simulations with an arc furnace model containing a sinusoidally varied arc resistance. To mitigate the flicker, a voltage source converter (VSC) has been connected in parallel with the arc furnace and simulated. The converter control is performed in the synchronously rotating dq-frame. Delays from measurement to realised converter current are of large importance for a well performing flicker mitigation. Measures have been taken in the control scheme to reduce the delay due to measurement filters and pulse width modulation (PWM). The flicker mitigation capability of a 60 MV A VSC is finally compared to that of a 120 MV A SVC in a case with random arc length modulation. The PST is in this specific case reduced from 3,8 down to 2,4 with the SVC and to 1,2 with the VSC.

	DSP Control of an Active Power Line Conditioning System By J. M. Carrasco; M. Perales; B. Ruiz; E. Galvan; L. G. Franquelo; S. Gutierrez; E. G. de Mendivil	[View] [Download]
Abstract: DSP based control of an active power line conditioning system is described in this paper. The control algorithm is proposed on the basis of the instantaneous reactive power theory. This aims at excellent compensation characteristics in transient states as well as steady states. The control functions are implemented using Texas Instrument low cost starter kit including a 32 bit floating point TMS320C31 DSP-based hardware and software. It was developped an specific adquisition board to be adapted to the Texas Instrument stater kit. The controller has been tested in the laboratory with the prototype and shows excellent performance.

	MPTC: AN ECONOMICAL ALTERNATIVE TO UNIVERSAL POWER FLOW CONTROLLERS By Ned Mohan	[View] [Download]
Abstract: It is important to have control over power transfer in interconnected power systems. This can improve stability and allow transmission lines to be loaded closer to their thermal limits than otherwise possible. It can minimize power losses by directing power to flow along its intended path. The objective of this paper is to describe a new power transfer controller called MPTC [1], which has most of the functionality of UPFC and has the potential to be much more cost-effective. This controller is based on a novel combination of proven technologies and recent advances in semiconductor devices. Application of this controller in improving power quality during voltage sag conditions is also discussed.

	APPLICATION OF THYRISTOR CONTROLLED SERIES CAPACITOR FOR DAMPING OF ELECTROMECHANICAL OSCILLATIONS By Ole Johan Hjemas; Mojtaba Noroozian	[View] [Download]
Abstract: This paper examines the improvement of power system dynamics by use of a thyristor controlled series capacitor (TCSC). Models suitable for incorporation in dynamic simulation programs for studying angle stability are analyzed. A control strategy for damping of electromechanical power oscillations using an energy function method is derived. The achieved control law is shown to be effective both for damping of large signal and small signal disturbances and are robust with respect to loading condition, fault location and network structure. Furthermore, the control input is easily attainable from the locally measurable variables. The effectiveness of the control is demonstrated for model power systems.