EPE Association: NORpie 2002 - Topic 11: DISTRIBUTION

NORpie 2002 - Topic 11: DISTRIBUTION
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   Fault Detection and Clearance in DC Distributed Power Systems
By P. Karlsson; J. Svensson [View]
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Abstract: This paper treats fault detection in DC distributed power systems, with emphasis on ground faults. The difficulty of detecting ground faults arises from the fact that the AC sources and loads are ungrounded or have heavy impedance to ground, on the converter side, to effectively block zero sequence currents otherwise flowing between the AC systems. A grounding scheme for the DC distribution system together with algorithms for detection of ground faults is presented. The proposed method detects ground faults on both the AC and DC sides and is extended to cover also short circuit faults with a minor work effort, which is also discussed.

   Behavior of Synchronous Machines Subjected to Transient Overvoltages
By F. Carlsson [View]
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Abstract: Voltage transients play an important part in the area of power quality. Transient overvoltages cause machine tripping due to breaking by overvoltage protection, which may lead to production losses. Apart from that, large torque peaks that may cause damage to the shaft or equipment connected to the shaft. High current peaks occur as well, which leads to thermal heating and tension. This paper shows on what conditions transients cause high peak torques and currents for synchronous machines, which is explained by a simple theory. Simulations verify the theory, and illustrate the torque and current peaks dependence on transient duration and magnitude.

NORpie 2002 - Topic 11: DISTRIBUTION
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2002 > NORpie 2002 - Topic 11: DISTRIBUTION
	[return to parent folder]

	Fault Detection and Clearance in DC Distributed Power Systems By P. Karlsson; J. Svensson	[View] [Download]
Abstract: This paper treats fault detection in DC distributed power systems, with emphasis on ground faults. The difficulty of detecting ground faults arises from the fact that the AC sources and loads are ungrounded or have heavy impedance to ground, on the converter side, to effectively block zero sequence currents otherwise flowing between the AC systems. A grounding scheme for the DC distribution system together with algorithms for detection of ground faults is presented. The proposed method detects ground faults on both the AC and DC sides and is extended to cover also short circuit faults with a minor work effort, which is also discussed.

	Behavior of Synchronous Machines Subjected to Transient Overvoltages By F. Carlsson	[View] [Download]
Abstract: Voltage transients play an important part in the area of power quality. Transient overvoltages cause machine tripping due to breaking by overvoltage protection, which may lead to production losses. Apart from that, large torque peaks that may cause damage to the shaft or equipment connected to the shaft. High current peaks occur as well, which leads to thermal heating and tension. This paper shows on what conditions transients cause high peak torques and currents for synchronous machines, which is explained by a simple theory. Simulations verify the theory, and illustrate the torque and current peaks dependence on transient duration and magnitude.