EPE Association: NORpie 2008 - Topic 04: POWER SYSTEMS

NORpie 2008 - Topic 04: POWER SYSTEMS
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2008 > NORpie 2008 - Topic 04: POWER SYSTEMS

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   An LVDC Distribution System Concept
By Pasi Salonen, Tero Kaipia, Pasi Nuutinen, Pasi Peltoniemi, Jarmo Partanen [View]
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Abstract: An LVDC distribution system is a new innovation in a field of electricity distribution. This paper presents the basic principles to use power electronics devices in electricity distribution systems. Recent technological and economical developments in power electronic components enable to apply power electronics in LV network. This development makes an LVDC distribution system concept establishment possible. In this respect the occurring progression connects power electronics and distribution system development strongly together. The LVDC distribution system basic concept concentrates at DC/AC interface focusing on implementation of customer-end inverter. The previously made analyses have shown that presented LVDC distribution system has existing techno-economical potential in electricity distribution networks.

   Customer-End Inverter in an LVDC Distribution Network
By Pasi Nuutinen, Pasi Salonen, Pasi Peltoniemi, Pertti Silventoinen [View]
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Abstract: An AC-based low-voltage distribution network can in some cases be replaced with a low-voltage direct current (LVDC) network. With a higher DC voltage, the transmission capacity increases compared with the AC system with the same cable cross-sectional area. The DC link feeds an inverter that converts the DC voltage to a 230 V single-phase or 400 V threephase AC voltage. Because the three-phase voltage is not necessarily needed in most residential applications, this paper presents two single-phase inverter topologies. Inverter modulation and its suitability for this kind of an application is discussed. The inverter efficiency and its requirements are also discussed in brief, yet more precise analyses are left for future studies. The conclusion is that a half-bridge topology is not suitable for this application, and therefore, a full-bridge inverter should be used instead.

   Control Principles for Blackstart and Island Operation of Microgrid
By H. Laaksonen, K. Kauhaniemi [View]
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Abstract: In some unexpected situations a microgrid may become unstable after transition to islanded mode and all DG units must be disconnected from microgrid. In case of these events a restoration strategy for microgrid blackstart is needed. Also if the islanded microgrid is divided into different protection zones in case of a fault, fault management strategy with capability of very fast operation is needed to maintain stability in the healthy section of the islanded microgrid. The control of microgrid voltage and frequency during the microgrid blackstart is not possible without energy storage unit. In this paper sequence of actions for the microgrid blackstart operation as well as control principles of some DG units during blackstart are defined and simulated with two different microgrid configurations. Also one simulation case considering fault management strategy and control principles during fault in islanded microgrid is presented. Based on the simulations dimensioning principles for the needed energy storage and size of simultaneously controlled loads can be drawn.

   Dynamic Modeling of Thyristor Controlled Series Capacitor in PSCAD and RTDS Environments
By Pasi VuorenpÃ¤Ã¤, Pertti JÃ¤rventausta, Jari Lavapuro [View]
[Download]

Abstract: Fast development of power electronics have enabled wide utilization of Flexible AC Transmission System (FACTS) devices for increasing electricity transmission capacity and stability of power systems. Among others, Thyristor Controlled Series Capacitor (TCSC) has been found to have great potential as a device capable of damping small signal oscillations in the power system. In addition, also noticeable voltage support and transient stability enhancement of the power system can be achieved using TCSC. In addition to the great possibilities of FACTS technology increase of these nonlinear and complex devices emphasizes the importance of extensive power system analysis to verify the overall stability of the power system. Consequently, in this paper research concerning operation of TCSC as a part of power system is presented. Main targets of the research are to develop new modeling techniques for TCSC and to study the effect of control system structure and surrounding network on operational characteristics of TCSC.

NORpie 2008 - Topic 04: POWER SYSTEMS
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2008 > NORpie 2008 - Topic 04: POWER SYSTEMS
	[return to parent folder]

	An LVDC Distribution System Concept By Pasi Salonen, Tero Kaipia, Pasi Nuutinen, Pasi Peltoniemi, Jarmo Partanen	[View] [Download]
Abstract: An LVDC distribution system is a new innovation in a field of electricity distribution. This paper presents the basic principles to use power electronics devices in electricity distribution systems. Recent technological and economical developments in power electronic components enable to apply power electronics in LV network. This development makes an LVDC distribution system concept establishment possible. In this respect the occurring progression connects power electronics and distribution system development strongly together. The LVDC distribution system basic concept concentrates at DC/AC interface focusing on implementation of customer-end inverter. The previously made analyses have shown that presented LVDC distribution system has existing techno-economical potential in electricity distribution networks.

	Customer-End Inverter in an LVDC Distribution Network By Pasi Nuutinen, Pasi Salonen, Pasi Peltoniemi, Pertti Silventoinen	[View] [Download]
Abstract: An AC-based low-voltage distribution network can in some cases be replaced with a low-voltage direct current (LVDC) network. With a higher DC voltage, the transmission capacity increases compared with the AC system with the same cable cross-sectional area. The DC link feeds an inverter that converts the DC voltage to a 230 V single-phase or 400 V threephase AC voltage. Because the three-phase voltage is not necessarily needed in most residential applications, this paper presents two single-phase inverter topologies. Inverter modulation and its suitability for this kind of an application is discussed. The inverter efficiency and its requirements are also discussed in brief, yet more precise analyses are left for future studies. The conclusion is that a half-bridge topology is not suitable for this application, and therefore, a full-bridge inverter should be used instead.

	Control Principles for Blackstart and Island Operation of Microgrid By H. Laaksonen, K. Kauhaniemi	[View] [Download]
Abstract: In some unexpected situations a microgrid may become unstable after transition to islanded mode and all DG units must be disconnected from microgrid. In case of these events a restoration strategy for microgrid blackstart is needed. Also if the islanded microgrid is divided into different protection zones in case of a fault, fault management strategy with capability of very fast operation is needed to maintain stability in the healthy section of the islanded microgrid. The control of microgrid voltage and frequency during the microgrid blackstart is not possible without energy storage unit. In this paper sequence of actions for the microgrid blackstart operation as well as control principles of some DG units during blackstart are defined and simulated with two different microgrid configurations. Also one simulation case considering fault management strategy and control principles during fault in islanded microgrid is presented. Based on the simulations dimensioning principles for the needed energy storage and size of simultaneously controlled loads can be drawn.

	Dynamic Modeling of Thyristor Controlled Series Capacitor in PSCAD and RTDS Environments By Pasi VuorenpÃ¤Ã¤, Pertti JÃ¤rventausta, Jari Lavapuro	[View] [Download]
Abstract: Fast development of power electronics have enabled wide utilization of Flexible AC Transmission System (FACTS) devices for increasing electricity transmission capacity and stability of power systems. Among others, Thyristor Controlled Series Capacitor (TCSC) has been found to have great potential as a device capable of damping small signal oscillations in the power system. In addition, also noticeable voltage support and transient stability enhancement of the power system can be achieved using TCSC. In addition to the great possibilities of FACTS technology increase of these nonlinear and complex devices emphasizes the importance of extensive power system analysis to verify the overall stability of the power system. Consequently, in this paper research concerning operation of TCSC as a part of power system is presented. Main targets of the research are to develop new modeling techniques for TCSC and to study the effect of control system structure and surrounding network on operational characteristics of TCSC.