Abstract:
The author was responsible for the Guarantee verification, testing and
eventually Acceptance of all of National Power's Combined Cycle Gas
Turbines for its commercial operation. It was discovered during the early
Acceptance Testing of these power stations that the Original Equipment
Manufacturers (OEMs) used empirical and indirect
~-~;
methods to derive the gas
turbine inlet temperature. This had direct impact on the life of the gas turbine
components and revenue earned in terms of increase in maintenance costs
and loss in generating power. It became absolutely imperative that alternative
methods should be quickly deployed on National Power's gas turbines to
substantiate or otherwise the already used indirect methods of running the
gas turbines.
A completely novel method of using ceramic thermocouples probes and
embedded ceramics onto blades to monitor elevated gas temperatures from
the early trials on large coal fired boilers to specially made burner rigs and the
Spey gas turbine are discussed. A patent for the ceramic temperature probe
was filed and approved. Finally, a non-intrusive infra-red thermal pyrometry
was installed on two of National Power's CCGT power stations. The report
includes technical aspects on emissivity, radiation, risks, obstacles
encountered, and the methodology used to install the pyrometry.
Using the data collated from Deeside Power Station, where two pyrometers
are currently installed, the results obtained from the engine simulation are
validated. Once the model was validated and the data correlated with the
actual data obtained, it can be concluded that the deployment of pyrometry
can control the diagnostics and operational behaviour of the CCGT plant. The
efficiency of the gas turbine was shown to increase by about 0:4% and the
corresponding increase in power was 1.3%, which would make a substantial
savings in the operating and maintenance costs to National Power. This was
estimated to be in access of £25,OOO,OOOlannum.
