Sulzer 55 MW generator winding upgrade improves reliability and reduces unscheduled stoppages
MACHINING & MACHINERY GENERATOR RELIABILITY
SULZER
Sulzer 55 MW generator winding upgrade improves reliability and reduces unscheduled stoppages
Large-scale manufacturing facilities in remote areas often rely on independent power generation sources to deliver the vast amounts of energy needed for operations . Turbo generators are often the cornerstones of these power sources . However , if they suffer unforeseen downtime , this reliance can result in a 100 % loss of production . This was the situation faced by an Indonesian cement producer , which turned to Sulzer to resolve the failure quickly and upgrade its generator to protect uptime .
Ground to an unscheduled stoppage
The breakdown of the 55 MW generator was caused by strand-tostrand faults that eventuated into a stator connection phase ground fault . Due to the excessive amount of winding oil contamination from a leaking bearing labyrinth seal , the ground fault flash resulted in a stator fire . As this was the only power source for the facility , production was immediately halted , risking the delivery of orders to customers . Any order obligations would need to be met by other facilities , placing stress on the cement producer ’ s regional operations . To resolve this , root cause analysis and a rapid temporary repair was requested by the cement plant management , followed by a full stator rewind at a more convenient time to suit their production commitments .
A thorough investigative inspection by Sulzer ’ s experts revealed that the failure was attributed to the stator winding design having parallel stranding , which caused
Sulzer was awarded the repair and upgrade project by direct appointment for the scope of winding and incorporating a 360 ° Roebel bar .
high circulating currents . The tracking across the surface of the stranding resulted in excessive winding temperature , eventually instigating the ground connection phase fault .
Rapidly responding to an urgent repair
Due to a proven track record supporting the customer ’ s various production facilities , Sulzer was awarded the repair and upgrade project by direct appointment for the scope of winding and incorporating a 360 ° Roebel bar . A leading independent service provider for rotating equipment , Sulzer is a global expert in generator repairs and upgrades for steam and gas turbines with a local presence in Indonesia .
The technical proposal of utilizing 360 ° Roebel bars presented by Sulzer ’ s global technical team convinced the cement plant management that it was the most optimal solution , along with timeline assurance . Furthermore , the customer was aware of Sulzer ’ s robust global supply chain , which would expedite the project and support the generator long into the future . Compounding these advantages , Sulzer could offer a lead time of 10 weeks , while other vendors were still offering parallel strand conductors and completion schedules of several months .
68 PECM Issue 65