Thermal and electrical testing of a new medium-range prototype synchronous generator
Kauppi, Lauri (2017)
2017
Sähkötekniikka
Tieto- ja sähkötekniikan tiedekunta - Faculty of Computing and Electrical Engineering
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Hyväksymispäivämäärä
2017-11-08
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201710252061
https://urn.fi/URN:NBN:fi:tty-201710252061
Tiivistelmä
This thesis was done for Wärtsilä Energy Solutions department and the purpose was to verify the thermal and electrical design of a new 12 MW middle-speed salient-pole synchronous generator. The design project has been conducted in co-operation with a Spanish generator manufacture Indar Electric and external stakeholders. The goal of the project was to achieve the designed rated power and thermal class B according to the IEC 60034-1 standard for the generator. Thermal class B limits the maximum allowed temperature of the windings to 130 °C.
Wärtsilä 12 MW generator features a new type of axial cooling ducts that were designed using computational fluid dynamics (CFD) software to improve the cooling of the rotor windings. The initiative to improve the rotor winding cooling came from previous experience in some projects where hot spots or local maximums of temperature in the windings have caused problems. At the worst, the hot spots can burn the insulation and destroy the whole windings. The temperature measurement of the hot spots is challenging due to the rotational movement of the rotor and practically it can only be made using telemetric measurement system.
The electromagnetic design of the generator was verified with electromechanical tests according to the IEC 60034-4 standard. From these tests, the standard parameters of the generator can be calculated which describe the electrical characteristics and transient stability of the generator. The thermal design and cooling of the generator was justified with a total of ten different heat run tests. The conclusion of the heat run test was that the rotor winding temperature rise was higher than the simulations expected and on the contrary, the stator winding temperature rise was lower. The effect of the axial rotor cooling ducts was less than expected but nevertheless they have a significant role in the cooling, especially for the stator windings. The hot spot measured with the RTDs was located close to the drive-end of the machine in each of the heat run tests but remained still below 100 ºC fulfilling the requirements of the thermal class B according to IEC 60034-1 standard. For the rotor windings, only in one of the heat run test setups the thermal class B requirements were fulfilled. There is a clear unbalance of thermal load between the stator and rotor windings. Finally, some design improvements will be discussed to improve the rotor winding cooling.
Wärtsilä 12 MW generator features a new type of axial cooling ducts that were designed using computational fluid dynamics (CFD) software to improve the cooling of the rotor windings. The initiative to improve the rotor winding cooling came from previous experience in some projects where hot spots or local maximums of temperature in the windings have caused problems. At the worst, the hot spots can burn the insulation and destroy the whole windings. The temperature measurement of the hot spots is challenging due to the rotational movement of the rotor and practically it can only be made using telemetric measurement system.
The electromagnetic design of the generator was verified with electromechanical tests according to the IEC 60034-4 standard. From these tests, the standard parameters of the generator can be calculated which describe the electrical characteristics and transient stability of the generator. The thermal design and cooling of the generator was justified with a total of ten different heat run tests. The conclusion of the heat run test was that the rotor winding temperature rise was higher than the simulations expected and on the contrary, the stator winding temperature rise was lower. The effect of the axial rotor cooling ducts was less than expected but nevertheless they have a significant role in the cooling, especially for the stator windings. The hot spot measured with the RTDs was located close to the drive-end of the machine in each of the heat run tests but remained still below 100 ºC fulfilling the requirements of the thermal class B according to IEC 60034-1 standard. For the rotor windings, only in one of the heat run test setups the thermal class B requirements were fulfilled. There is a clear unbalance of thermal load between the stator and rotor windings. Finally, some design improvements will be discussed to improve the rotor winding cooling.