Case Studies
A 250MW CA Parsons turbine IP cylinder was opened for inspection and severe shroud separation was found in the rotating as well as stationary blade shrouds. The norm is that this case would be a total re-blade of the cylinder. This was not possible due to spares availability, cost and expected life of the plant.
The 320 MW HTC unit was shut down for inspection of the HP Emergency Stop valve (ESV) and Governing valves (GV’s) due to restricted valve movement experienced in operation. Upon opening the ESV it was found that the chest seat had come adrift and damaged the spindle seat as well as the steam chest location areas. The seat diffuser section had broken up and pieces went through into the GV’s.
The 17MW Geothermal steam turbine had been operating for many years with a leak in the casing half joint. The leaks that were at the same position on both sides of the casing could be traced back three outage cycles and each time an attempt was made to resolve the leak.
The Unit 1, 250mW steam turbine was shut down in January 2019 for the scheduled overhaul and statutory inspection work on the complete boiler, turbine and generator. ProGen was contracted to undertake the work relating to the steam turbine and generator.
The Coal-Fired Thermal Power Station (Philippines) was shut down annually to undertake maintenance and repairs to the 320MW Steam Turbine Generator (STG), Boilers and ancillary Balance of Plant (BOP) equipment. ProGen was contracted over the last four Overhauls (2016 to 2019) to undertake the Client technical support function relating to work on the STG and of its boiler feed pumping plant.
The 100MW Geothermal Power Station was shut down in January 2018 for the scheduled overhaul work on the Steam field, Separators and Scrubbers, Cooling Tower, Steam Turbine Generator (STG), Hot Well Pump (HWP) and Transformer replacement. ProGen was contracted to undertake the work relating to the STG and its auxiliary plant.
The 400MW Combined Cycle Gas-Fired Thermal Power Plant was shut down in late October 2018 for the scheduled overhaul work on the combined cycle, steam turbine generator (STG) and balance of plant (BOP) equipment. ProGen was contracted to undertake the work relating to the STG and its auxiliary plant.
The 100MW Geothermal Power Station was shut down in January 2018 for the scheduled overhaul work on the Steam field, Separators and Scrubbers, Cooling Tower, Steam Turbine Generator (STG), Hot Well Pump (HWP) and Transformer replacement. ProGen was contracted to undertake the work relating to the STG and its auxiliary plant.
The 20MW organic Rankine cycle bi-turbine units were suffering from a higher than expected bearing failure rate. The alignment of the turbines to the generator is considered one of the primary possibilities why the bearings failure rate is higher than expected. The distortion of the turbine structure due to the exhaust pipe movement was suspected as contributor to the bearing failures due to the impact on alignment with the generator.
Turbine-Generator sets must be flat and correctly aligned to function reliably. The units are aligned when the plant is constructed, but they do not always stay that way. The plinth and foundation that supports the turbine and generator can twist and sag over time. This deformation can result in distortion of turbine casings and misalignment of the units. Many plant operators are not aware that this can and does happen. These conditions can result in a number of (often costly) flow-on effects. We aim to demonstrate in this paper that laser measurement has proven to be an integral part of the diagnosis and solution of these conditions. Turbine owners and operators stand to benefit from solving these issues through reducing unplanned downtime and costly repairs, and increasing performance.
The results of a systematic approach to several extraordinary turbine maintenance outages that were executed over one year by ProGen as the service provider will be discussed. All of these outages were conducted successfully within the time and budget parameters set. There were no commissioning or operational issues encountered upon return to service. All of the outages were planned to a tight schedule based on optimizing historical performances. Although emergent work was discovered during most of the projects the work was able to be managed within the allowed time frame and within the planned budget.
This paper reports the findings of a review of the repair options for the rotor removed in 2012 from the Star Energy Wayang Windu Geothermal Power Station 110MW Unit 1 Turbine. The rotor was replaced as a result of an assessment by the OEM (Fuji) of the erosion damage found in the 2009 overhaul. A new rotor was installed and the rotor was set aside as an emergency spare.