As I have most of my experience on Gas Turbines, and operators of my team had have faced this issue of failures especially during cold weather during restart of machine after long shutdowns. Even in some cases shutdown of few hours in extreme cold weather.
During my tenure at 250MW Karbala Power Station, I noticed that the Ministry engineers use to keep both gas turbines on FSNL between Midnight and early morning and then were synchronizing both with grid in morning peak hours, our old Pakistani operators were following their instructions. Remind you, Diesel oil is most expensive choice to burn it without generation a watt in Iraq, a oil producing country.
I investigated the reason and as per engineers they use to keep these units FSNL because there were failure to restart most of times during the morning peak load hours. After investigations, I meet with the operation manager of our Iraqi team and requested them to let me shutdown unit and I would make these units (GE Frame 9E gas Turbines) restarted next morning as per plan. Most of team members were scared that if units fails again and then who will be responsible, then I assured them and took responsibility. Engineers allowed me to shutdown one unit only when it was to be placed on standby.
Next day morning at 05:30 AM I lead my team and started the gas turbine but it failed to fire in first try and the our Ministry engineer widened his eyes at me, in response I asked him to be patient. I advised operator to place GT extended purge cycle for 15 minutes, and then we tried to start and machine was fired successfully and many friends standing by heard the sigh of relief from all sides.
Question why GT failed to fire on first try? answer is the metal temperature was cooler for the diesel oil to ignite. The oil when comes out of the nozzle is subjected to additional cooling and ignition of 30 second cycle was not enough to ignite the sub relatively cooler diesel. When gas turbine was placed on extended time of purge cycle, the hot air discharged of compressor passes through the combustion section and turbine and started warming the metal, when the gas turbine exhaust gas temperature is above 34 degrees and then initiating fire sequence causes diesel to ignite in relatively warm atmosphere inside the combustion chamber as compared to first start.
I have seen 100s of successful starts for gas turbine using above technique, which in fact off the book technique.