EPE Association: EPE 1989 - 07 - Lecture Session 1.7: POWER ELECTRONICS IN GENERATION AND TRANSMISSION

EPE 1989 - 07 - Lecture Session 1.7: POWER ELECTRONICS IN GENERATION AND TRANSMISSION
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   THE USE OF A TCR FOR HIGHER FLEXIBILITY OF THE AUSTRIAN HVDC BACK-TO-BACK LINKS
By G. Moraw [View]
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Abstract: The Austrian HVDC back-to-back links connect with a power of 550 MW each the UCPTE- with the CMEA-network. To increase the flexibility of their operation a thyristor-controlled reactor (TCR) with a short-time power of 580 MVar and a continuous power of 150 MVar will be installed. This device allows to connect both HVDC back-to-back links via the same single-system 400-kV-line to Hungary or Czechoslovakia, as well as a parallel operation of the HVDC link Dürnrohr with the hydro-power plant Altenwörth by reducing the load rejection overvoltages to suitable values. In the paper the operational features, the studies performed and the design of the TCR are described.

   SUITABLE HVDC CONTROL STRATEGIES FOR STABILIZING AC NETWORKS
By Dusan Povh; Manfred Weibelzahl [View]
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Abstract: The primary task of a HVDC tie is to transmit steady-state active power and thus exchange the power between two networks of different frequencies or which do not operate in synchronism. The steady-state operating points are determined by the thyristor parameters. In general, losses must be kept low for cost reasons. This leads to the familiar pattern of extinction angle control on the inverter side and current control on the rectifier side (or camparable control strategies). The field of activity of a HVDC tie is extending beyond the traditional task of active power transmission. Increasing attention is being given to the network parameters, i.e. active power, reactive power and harmonics. The time range in question for the interaction between the HVDC and the network extends from steady-state and quasi steady-state operation through the transient range to modulation. Very different stabilizing strategies are adopted depending on the particular requirements placed on the HVDC equipment by the network. lndividual stabilization strategies are described with reference to actual HVDC installations.

   DESIGN ASPECTS AND APPLICATIONS OF DAMPED AC-FILTERS FOR HVDC AND SVC CONNECTED WEAK AC-SYSTEMS
By N. Christl; P. Lützelberger; K. Sadek [View]
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Abstract: The design of harmonic AC-filters for an HVDC converter station connected to a weak AC-system has to consider both steady state and transient performance requirements. For weak AC-systems, the dynamic (DOV) and saturation (SOV) overvoltages after load rejection are considerably high. DOV-overvoltages can be reduced by SVC (TCR). Saturation overvoltages can be damped by using appropriate AC-filters with damping effect at low-order harmonics. The paper shows the comparison between configurations of AC-filters and SVC in damping these overvoltages after load rejection. The AC-system is chosen to be resonant with the connected AC-filters near the 3rd harmonic. The objective is to reduce the overvoltages on the AC-busbar below the design value of existing breakers to allow switching off sub-banks.

   ON THE FAULT-RECOVERY OF HVDC SYSTEMS
By R. Joetten; H. Ring; Th. Wess; Y. Zong [View]
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Abstract: The parameters which influence the recovery of an HVDC system after faults in the adjacent a.c. systems and at the d. c. side are discussed. The control measures which are applied to secure a fast recovery without follow-up disturbances are reviewed, with the steady state control characteristics and the sequences for the recovery. A control based on a microprocessor and a signal processor allows a better identification of the type of fault and adaption of the reaction. The gate control can change between different degrees of symmetry filtering. Tests with a benchmark system set up at a real-time simulator for power system studies are presented.

EPE 1989 - 07 - Lecture Session 1.7: POWER ELECTRONICS IN GENERATION AND TRANSMISSION
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 07 - Lecture Session 1.7: POWER ELECTRONICS IN GENERATION AND TRANSMISSION
	[return to parent folder]

	THE USE OF A TCR FOR HIGHER FLEXIBILITY OF THE AUSTRIAN HVDC BACK-TO-BACK LINKS By G. Moraw	[View] [Download]
Abstract: The Austrian HVDC back-to-back links connect with a power of 550 MW each the UCPTE- with the CMEA-network. To increase the flexibility of their operation a thyristor-controlled reactor (TCR) with a short-time power of 580 MVar and a continuous power of 150 MVar will be installed. This device allows to connect both HVDC back-to-back links via the same single-system 400-kV-line to Hungary or Czechoslovakia, as well as a parallel operation of the HVDC link Dürnrohr with the hydro-power plant Altenwörth by reducing the load rejection overvoltages to suitable values. In the paper the operational features, the studies performed and the design of the TCR are described.

	SUITABLE HVDC CONTROL STRATEGIES FOR STABILIZING AC NETWORKS By Dusan Povh; Manfred Weibelzahl	[View] [Download]
Abstract: The primary task of a HVDC tie is to transmit steady-state active power and thus exchange the power between two networks of different frequencies or which do not operate in synchronism. The steady-state operating points are determined by the thyristor parameters. In general, losses must be kept low for cost reasons. This leads to the familiar pattern of extinction angle control on the inverter side and current control on the rectifier side (or camparable control strategies). The field of activity of a HVDC tie is extending beyond the traditional task of active power transmission. Increasing attention is being given to the network parameters, i.e. active power, reactive power and harmonics. The time range in question for the interaction between the HVDC and the network extends from steady-state and quasi steady-state operation through the transient range to modulation. Very different stabilizing strategies are adopted depending on the particular requirements placed on the HVDC equipment by the network. lndividual stabilization strategies are described with reference to actual HVDC installations.

	DESIGN ASPECTS AND APPLICATIONS OF DAMPED AC-FILTERS FOR HVDC AND SVC CONNECTED WEAK AC-SYSTEMS By N. Christl; P. Lützelberger; K. Sadek	[View] [Download]
Abstract: The design of harmonic AC-filters for an HVDC converter station connected to a weak AC-system has to consider both steady state and transient performance requirements. For weak AC-systems, the dynamic (DOV) and saturation (SOV) overvoltages after load rejection are considerably high. DOV-overvoltages can be reduced by SVC (TCR). Saturation overvoltages can be damped by using appropriate AC-filters with damping effect at low-order harmonics. The paper shows the comparison between configurations of AC-filters and SVC in damping these overvoltages after load rejection. The AC-system is chosen to be resonant with the connected AC-filters near the 3rd harmonic. The objective is to reduce the overvoltages on the AC-busbar below the design value of existing breakers to allow switching off sub-banks.

	ON THE FAULT-RECOVERY OF HVDC SYSTEMS By R. Joetten; H. Ring; Th. Wess; Y. Zong	[View] [Download]
Abstract: The parameters which influence the recovery of an HVDC system after faults in the adjacent a.c. systems and at the d. c. side are discussed. The control measures which are applied to secure a fast recovery without follow-up disturbances are reviewed, with the steady state control characteristics and the sequences for the recovery. A control based on a microprocessor and a signal processor allows a better identification of the type of fault and adaption of the reaction. The gate control can change between different degrees of symmetry filtering. Tests with a benchmark system set up at a real-time simulator for power system studies are presented.