Wyniki wyszukiwania - BazTech

1

Zaawansowane zabezpieczenie różnicowe linii z kanałem komunikacyjnym o ograniczonej przepustowości

Kasztenny B., Fischer N.

Wiadomości Elektrotechniczne

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2014

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R. 82, nr 6

26--30

PL

Przedstawiono zasady funkcjonowania zabezpieczenia różnicowoprądowego linii elektroenergetycznych z kanałem komunikacyjnym z ograniczoną przepustowością w sytuacji nasycania się przekładników prądowych oraz w przypadku zakłóceń w kanale komunikacyjnym.

EN

The paper presents operation principles of differential protection of electric power lines with limited capacity communication channel in saturated current transformers case and disturbed communication channel case.

2

Simplifying and improving protection of temporary and unusual bus configurations with microprocessor-based relays

Labuschagne C, Fischer N., Kasztenny B.

Present Problems of Power System Control

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2014

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Nr 5

5--32

EN

Breaker substitution, stub bus, and station bypass are temporary substation configurations used to facilitate the maintenance of primary equipment while keeping assets in service and supplying loads. These configurations provide considerable operational advantages but create challenges for protection systems. Traditional solutions to temporary bus configurations required for electromechanical relays utilize test and bypass switches to ensure the affected relays are provided with the appropriate currents and voltages and the trip signals are routed to the appropriate breakers. In some cases, spare relays, settings changes, and the rerouting of pilot signals and communications have been required. All these manual operations increase the danger of misoperation when making changes, during temporary configurations, or when restoring to the normal configuration. As a result, temporary bus configurations have been carefully considered and often avoided, resulting in underutilization of the network assets. This paper shows how modern microprocessor-based relays can simplify applications under temporary bus configurations, eliminate the need for any manual reconfiguration, and improve the performance of protection. These benefits stem from the ability to connect multiple current and voltage inputs, the ability to trip multiple breakers, communication between relays, and programmable logic, allowing automatic detection and dynamic response to temporary bus configurations.

3

Tutorial on operating characteristics of microprocessor-based multiterminal line current differential relays

Kasztenny B, Benmouyal G, Altuve H J, Fischer N

Present Problems of Power System Control

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2013

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Nr 3

s. 5--73

EN

Line current differential (87L) protection schemes face extra challenges compared with other forms of differential protection, in addition to the traditional requirements of sensitivity, speed, and immunity to current transformer saturation. Some of these challenges include data communication, alignment, and security; line charging current; and limited communications bandwidth. To address these challenges, microprocessor-based 87L relays apply elaborate operating characteristics, which are often different than a traditional percentage differential characteristic used for bus or transformer protection. These sophisticated elements may include adaptive restraining terms, apply an Alpha Plane, use external fault detection logic for extra security, and so on. While these operating characteristics provide for better performance, they create the following challenges for users: x Understanding how the 87L elements make the trip decision. x Understanding the impact of 87L settings on sensitivity and security, as well as grasping the relationship between the traditional percentage differential characteristic and the various 87L operating characteristics. x Having the ability to transfer settings between different 87L operating characteristics while keeping a similar balance between security and dependability. x Testing the 87L operating characteristics. These issues become particularly significant in applications involving more than two currents in the line protection zone (multiterminal lines) and lines terminated on dual-breaker buses. This paper is a tutorial on this relatively new protection topic and offers answers to the outlined challenges.

4

Generator split-phase protection

Kim S., Finney D., Fischer N., Kasztenny B.

Present Problems of Power System Control

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2012

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Nr 2

5-40

EN

The stator winding of a hydrogenerator is often made up of coils with multiple turns in the same slot. It is therefore possible for faults to develop between adjacent turns on the same phase (turn-toturn faults). These faults cannot be detected by the stator differential protection because there is no difference between the neutral- and terminal-side currents. Split-phase protection, an overcurrent element responding to the difference between the currents in the winding parallel branches, is typically provided to detect these faults. Ideally, the split-phase element should be sensitive enough to detect a single shorted turn. Despite the fact that the current in this turn can be six to seven times the machine nominal current, the current seen by the split-phase protection can be quite small, in the order of one-twentieth of the generator full-load current. In addition, a spurious split-phase current can be measured due to current transformer (CT) errors, saturation during external faults in particular. Therefore, primary considerations in the application of split-phase protection are the method of measuring the difference in the currents between the parallel branches and the proper selection of the CT used for this purpose.

5

Hydrazinium 5-Aminotetrazolate: an Insensitive Energetic Material Containing 83.72% Nitrogen

Fischer N., Klapötke T. M., Scheutzow S., Stierstorfer J.

Central European Journal of Energetic Materials

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2008

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Vol. 5, nr 3-4

3-18

EN

Hydrazinium 5-aminotetrazolate (2) was synthesized via two facile routes. Both the reaction of 5-amino-1H-tetrazole (1) with hydrazine hydrate in aqueous solution and the reaction of 1 with diluted hydrazine solution in THF yield 2 in excellent purities and yields. 2 was characterized comprehensively by X-ray diffraction, IR, Raman and multinuclear NMR spectroscopy, mass spectrometry, elemental analysis and differential scanning calorimetry. The heat of formation was calculated (CMS-4M) using the atomization method to be 373 kJ mol-1. With this value and the X-ray density several detonation parameter (heats of explosion, detonation pressure, detonation velocity, explosion temperature) were calculated with the EXPLO5 computer software. An incredible high value (9516 m s-1) was obtained for the detonation velocity. Therefore experimentally tests to determine the velocity of detonation were performed. In addition the use of 2 in solid propellant compositions was calculated and tested in combination with oxidizers, e.g. ammonium dinitramide. Lastly the sensitivities towards impact, friction and electrostatic discharge were determined with the BAM drophammer, friction tester and an ESD machine.