Stator Cooling Water Systems: Preventive And Proactive Approaches To Reduce Forced Outages
Dr Thomas Bauer
Consultand and Co-Founder
SvoBa Tech, Inc
Large turbo generators employ direct water cooling through hollow conductors to transfer heat away from the stator bars. Various circumstances can lead to plugging of these copper hollow conductors when existing copper oxides are mobilized. Reduced heat transfer from lower coolant flow results in power downrates, reduced insulation lifetime, forced outages and/or irreversible damage to the generator.
The focus of this publication is on two different areas: first, proper monitoring of the stator cooling water system is discussed. It is important to not only focusing on what to monitor, but also proper probe locations as well as monitoring intervals. This helps in keeping the water chemistry under tight control and can work as an early detection tool for problems.
The second part discusses a proactive approach. It will show benefits of how to successfully prevent forced outages and damage to the generator by proactively cleaning the system within appropriate intervals.
In both cases, operational experience of best practices are presented.
Thomas Bauer (Ph.D., Material Science, Swiss Federal Institute of Technology (ETH) Zurich, Switzerland) worked for Siemens Transformers Austria in Weiz, Austria during his master studies in the field of chemistry-related issues with transformer oils. After his Ph.D. he joined Alstom Thermal Power in Baden, Switzerland in 2012 where he worked in the field of water-cooled generators and especially on chemical cleaning of stator and rotor coils. Additionally, he was project manager of R&D projects related to water-cooled generators. In September 2014 he co-founded SvoBaTech, Inc. an independent service provider for stator cooling water systems (SCWS). His key competence is on an all-in-one solution for SCWS, ranging from designing and commissioning of alkalization systems and support in troubleshooting and data analyses to chemical cleaning of stator and rotor coils as well as updating SCWS instrumentation.