Page 11 - Uninterruptible Power Supplies

Standby Power Generating Sets
Standby Power Generating Sets 9

2314—Specification for Gas Turbine Acceptance Tests, which are briefly
discussed below. There are other international or British Standards relat-
ing specifically to gas turbines and noise measurement, exhaust gas emis-
sions, vibration, fuels, a glossary of terms, and graphic symbols.
ISO 3977—Gas Turbine Procurement lists a variety of operational
modes for annual running hours and for the number of starts per
annum. There are four classes for annual running hours: Class A allows
for up to 500 hours per annum and would suit most standby applica-
tions, other classes allow for up to 2000, 6000, and 8760 hours per
annum. There are five ranges for the number of starts per annum: up
to 25, up to 100, up to 500, above 500, and continuous operation. Range
III allows for up to 100 starts per annum and would be suitable for most
standby applications; Range IV allows for 25 starts per annum which
would restrict the number of test runs. The standard includes other
sections on fuel, control and protective devices, vibration, sound, and
pollution. There is a section listing the technical information to be sup-
plied by the purchaser with the enquiry, and another on the technical
information to be supplied by the manufacturer when tendering.
ISO 2314—Specification for Gas Turbine Acceptance Tests describes
in some detail the procedures to be followed when undertaking accep-
tance tests which may be on a complete generating set including the
generator.

Standard Reference Conditions for Gas Turbines

The standard conditions for gas turbines are specified in ISO 2314 and
ISO 3977 as:
1. Intake air at compressor flange
a. A total pressure of 101.3 kPa
b. A total temperature of 15°C
c. A relative humidity of 60 percent
2. Exhaust at turbine exhaust flange
a. A static pressure of 101.3 kPa
The barometric pressure of 101.3 kPa is equivalent to operating at
sea level. The temperature of 15°C imposes some limitation in temper-
ate and warm climates. The manufacturer should be aware of the alti-
tude at which the turbine will operate and of the maximum expected
ambient temperature.

Alternating Current Generators
Power passes from the engine through the coupling to the generator
which will take one of two forms:

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