Transcript
Footprint/substitute generators for type series FT and FTH Background The two-pole generators of the type series FT (air-cooled) and FTH (hydrogen-cooled), built in the past up to a maximum capacity of about 130 MVA, more and more require extensive reconstruction measures due to the aging of the components, e.g. rotor and stator windings. In many cases, a safe operation of these generators can no longer be ensured due to outworn insulation. Instead of an expensive rewinding many operators decode for global upgrades, resulting in a lasting increase of the plant’s operating efficiency, considering expenses and reconstruction period at the same time.
Footprint concept for generators of type series FT and FTH The newly developed concept combines state-of-the-art generator technology with existing interfaces of old generator types, considering the operator’s commercial interests. The basic idea is an integration of existing active components used in new generators for the design of matching substitute machines (see figures 1 and 2), that include all the relevant existing interfaces of the current installation (shaft height, foundations etc.), thus allowing for a quick exchange.
Investigations have shown that economically and technically speaking, an exchange of individual components as well as a reproduction of the original machine is inappropriate. For this reason a footprint or substitution concept was developed for the above mentioned generator types.
Fig. 1: View of an air-cooled FT generator with a present output of 25 MVA that may be increased to approximately 35 MVA
Answers for energy.
Fig. 2: Lateral view of a newly developed generator that is a substitute for the generator shown in fig. 1
The developed footprint concept is applicable for all the FT generators, independent from design and cooling system, for all established requirements: Frequencies 50 Hz and 60 Hz Voltages 6,3 kV /10,5 kV /13,0 kV Hydrogen-cooled FTH generators may optionally be replaced with new, more efficient, air-cooled machines. Hereby, the abolition of operational costs for hydrogen systems effects a significant saving potential for operators.
Excitation system exchange Increase of costs and extended delivery time for spare parts and services connected with legacy excitation systems of FT generators give economic reason to their modernization.
Published by and copyright © 2008: Siemens AG Energy Sector Freyeslebenstrasse 1 91058 Erlangen, Germany Siemens Power Generation, Inc. 4400 Alafaya Trail Orlando, FL 32826-2399, USA
The exchange of analogue original excitation systems with digital wearless stateof-the-art systems reduces operational costs and at the same time increases the availability of the installation. The direct-current exciter sets employed in most cases (see fig. 3) are replaced by modern, brushless three-phase alternatingcurrent exciters.
For more information, contact our Customer Support Center. Phone: +49 180/524 70 00 Fax: +49 180/524 24 71 (Charges depending on provider) e-mail:
[email protected] www.siemens.com/energy-support
Altogether, the Footprint concept offers operators the following benefits: Generator substitution takes place using a design that is adapted to the respective installation (shaft height, anchoring, flange connection, ventilation etc.), resulting in short downtime. If required the nominal output of the generator can be increased, especially when considering a future power enhancement of the entire machine unit. Based on reduced output power the operating conditions losses are decreased, as well as heating of the components. An implementation of other cooling systems and designs is possible, e.g. a changeover to a closed ventilation system. Increased operational safety and availability by means of component renewal. Longer service life. Additional benefits after exchanging the old excitation system: Extension of maintenance intervals Reduced contamination due to carbon dust Separate closed ventilation system as bypass of the main generator’s cooling loop
Order No. A96001-G90-B186 Printed in Germany 1386 J DA 0208 1.
Lower operational costs due to - reduction of wear parts (stock-keeping) - abolition of exciter bearing
All rights reserved. Subject to change without prior notice. Printed on paper treated with chlorinefree bleach. Trademarks mentioned in this document are the property of Siemens AG, its affiliates, or their respective owners. The information in this document contains general descriptions of the technical options available, which may not apply in all cases. The required technical options should therefore be specified in the contract.
Benefits
Fig. 3: Excitation set of an FT generator
