EPS mobilised twice to 2 different sites for gas turbine fault finding, resolving the issue quickly and efficiently
EPS has a team of highly experience engineers and when it comes to gas turbine fault finding, they have all the tools they need to resolve the issue. This means they can analyse the data quickly and provide a plan to resolve the issue quickly and efficiently.
Gas Turbine Fault Finding Trip No 1
The first mobilisation was to an SGT200-2S which was shutting down on a fuel valve error after the fitment of a new gas turbine, power turbine and both gearboxes. These particular engines had been retrofitted 3 years ago by EPS with Woodward GS16 fuel valves, and have been performing impeccably since. Both the old and new engines start first time, every time.
The initial data was analysed and it could be seen the the fuel valve was going out on instantaneous demand error. This particular shutdown looks to see if the fuel valve is being requested to move more than a set percentage with a short time frame (100ms). This is to ensure that the valve cannot just be wound wide open or closed.
A datalog was set up in the Rustronic which has a resolution down to 10ms. This is an excellent tool for gas turbine fault finding even though the control system is old. It is as capable as any modern system providing you understand how it operates. A run was undertaken and sure enough, the fuel valve started to oscillate until it eventually tripped. The data was analysed and it could be seen the the fuel valve was doing what the governor software was demanding. This showed there was no issue at all with the fuel valve and its associated components.
What could be seen from the fast data however, was the power turbine speed was increasing and decreasing very quickly by ~500rpm in less than 0.2s. After looking at the droop control logic, it was determined that there was potentially an issue with the speed measurement. The speed probe for the governor was removed and found to have contacted the toothed pickup ring. This was replaced with a new item from the customers stores and the engine started and run up onto load successfully.
Gas Turbine Fault Finding Trip No 2
The second trip was to help resolve a long standing issue a customer had with spurious trips on speed. The customer and its service provider had spent many months looking into the issue without finding a solution. This had involved multiple checks on cabling, speed probes, controls equipment replacement etc.
EPS’s approach to this was to double up the speed signal into another slot. The control signal was moved across to this slot, however software was written to enable the monitoring of the existing slot. By using this approach we could be confident that we would know if the issue had been resolved. An additional alarm was added to the HMI to show the operator if a spurious spike had occurred on the old slot. Soon after restarting the turbine the new alarm was encountered on the unit, however the unit remained operational. A second occurrence was noted after 48hrs running, however the turbine had remained running since the restart.
Why choose EPS for your Gas Turbine fault finding?
With many years of gas turbine fault finding EPS is very adept at the unusual problems that can be seen when operating large pieces of equipment. Using our small but highly experienced team we can come up with solutions to resolve the issue in the minimum amount of time. Our in-depth knowledge of both the controls, package and gas turbine itself allows us to consider all the possible issues and engineer a way to get to a solution quickly.
If you are experiencing issues that you cannot get to the bottom of – either yourselves or with your current service provider – don’t hesitate to get in touch to see how we can help you.
