Use of Discharge Resistor to Improve Transient De-Excitation in Brushless Synchronous Machines
The discharge resistor is only used in case of electrical trip to reduce the field current as fast as possible and to minimize the damages produced by the short-circuit current supplied by the synchronous machine. The connection of the discharge resistor is done by opening the field breaker and it i...
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doaj-1f8e65a5f0b842d693e235f3f57c3e7e2020-11-24T21:49:54ZengMDPI AGEnergies1996-10732019-07-011213252810.3390/en12132528en12132528Use of Discharge Resistor to Improve Transient De-Excitation in Brushless Synchronous MachinesEmilio Rebollo0Carlos A. Platero1David Talavera2Ricardo Granizo3Department of Electrical Engineering, ETS Ingenieros Industriales, Universidad Politécnica de Madrid, C/José Gutierrez Abascal, 2, 28006 Madrid, SpainDepartment of Electrical Engineering, ETS Ingenieros Industriales, Universidad Politécnica de Madrid, C/José Gutierrez Abascal, 2, 28006 Madrid, SpainDepartment of Electrical Engineering, ETS Ingenieros Industriales, Universidad Politécnica de Madrid, C/José Gutierrez Abascal, 2, 28006 Madrid, SpainDepartment of Electrical Engineering, ETS Ingeniería y Diseño Industrial, Universidad Politécnica de Madrid, C/Ronda de Valencia, 3, 28012 Madrid, SpainThe discharge resistor is only used in case of electrical trip to reduce the field current as fast as possible and to minimize the damages produced by the short-circuit current supplied by the synchronous machine. The connection of the discharge resistor is done by opening the field breaker and it implies a large negative voltage in the field winding. This negative voltage is limited to 80% of the winding insulation voltage. On the other hand, in case of a transient de-excitation, at the first moment, the automatic voltage regulator (AVR) reduces the field voltage to the minimum. In case of one-quadrant rectifier type AVR, the minimum voltage is zero and in case of two-quadrant rectifier AVR, the minimum voltage is close to the ceiling voltage with negative polarity. In both cases, the minimum voltages are much smaller than the negative voltage produced by the connection of the discharge resistor. This paper presents a new system that improves the transient de-excitation of synchronous machines using the discharge resistor by an additional static field breaker (SFB). The control of the static field breaker and consequently the connection and disconnection of the discharge resistor is done based on the output field voltage supplied by the AVR. This allows the exciter field current to be reduced in a faster way and continue with the normal operation of the machine after the transient. In this study, the correct operation of the additional static field breaker (SFB) has been validated by computer simulations and experimental test in a 15 MVA generator comprising a commercial one-quadrant rectifier AVR type obtaining excellent results.https://www.mdpi.com/1996-1073/12/13/2528synchronous generator excitationbrushless rotating machinessynchronous machinesmachine protectionde-excitation systemde-excitation time constantprotection systembrushless excitationbrushless synchronous machine testing |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Emilio Rebollo Carlos A. Platero David Talavera Ricardo Granizo |
spellingShingle |
Emilio Rebollo Carlos A. Platero David Talavera Ricardo Granizo Use of Discharge Resistor to Improve Transient De-Excitation in Brushless Synchronous Machines Energies synchronous generator excitation brushless rotating machines synchronous machines machine protection de-excitation system de-excitation time constant protection system brushless excitation brushless synchronous machine testing |
author_facet |
Emilio Rebollo Carlos A. Platero David Talavera Ricardo Granizo |
author_sort |
Emilio Rebollo |
title |
Use of Discharge Resistor to Improve Transient De-Excitation in Brushless Synchronous Machines |
title_short |
Use of Discharge Resistor to Improve Transient De-Excitation in Brushless Synchronous Machines |
title_full |
Use of Discharge Resistor to Improve Transient De-Excitation in Brushless Synchronous Machines |
title_fullStr |
Use of Discharge Resistor to Improve Transient De-Excitation in Brushless Synchronous Machines |
title_full_unstemmed |
Use of Discharge Resistor to Improve Transient De-Excitation in Brushless Synchronous Machines |
title_sort |
use of discharge resistor to improve transient de-excitation in brushless synchronous machines |
publisher |
MDPI AG |
series |
Energies |
issn |
1996-1073 |
publishDate |
2019-07-01 |
description |
The discharge resistor is only used in case of electrical trip to reduce the field current as fast as possible and to minimize the damages produced by the short-circuit current supplied by the synchronous machine. The connection of the discharge resistor is done by opening the field breaker and it implies a large negative voltage in the field winding. This negative voltage is limited to 80% of the winding insulation voltage. On the other hand, in case of a transient de-excitation, at the first moment, the automatic voltage regulator (AVR) reduces the field voltage to the minimum. In case of one-quadrant rectifier type AVR, the minimum voltage is zero and in case of two-quadrant rectifier AVR, the minimum voltage is close to the ceiling voltage with negative polarity. In both cases, the minimum voltages are much smaller than the negative voltage produced by the connection of the discharge resistor. This paper presents a new system that improves the transient de-excitation of synchronous machines using the discharge resistor by an additional static field breaker (SFB). The control of the static field breaker and consequently the connection and disconnection of the discharge resistor is done based on the output field voltage supplied by the AVR. This allows the exciter field current to be reduced in a faster way and continue with the normal operation of the machine after the transient. In this study, the correct operation of the additional static field breaker (SFB) has been validated by computer simulations and experimental test in a 15 MVA generator comprising a commercial one-quadrant rectifier AVR type obtaining excellent results. |
topic |
synchronous generator excitation brushless rotating machines synchronous machines machine protection de-excitation system de-excitation time constant protection system brushless excitation brushless synchronous machine testing |
url |
https://www.mdpi.com/1996-1073/12/13/2528 |
work_keys_str_mv |
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