2.13.2
Voltage Balance
At any balanced load between 75 and 100% of rated output capacity, the
difference in line-to-neutral voltage among the 3 phases shall not exceed
1% of the average line-to-neutral voltage. For a single-phase load
condition, consisting of 25% load at unity power factor placed between any
phase and neutral with no load on the other 2 phases, the maximum
simultaneous difference in line-to-neutral voltage between the phases shall
not exceed 3% of rated line to neutral voltage. The single-phase load
requirement shall be valid utilizing normal exciter and regulator control.
The interpretation of the 25% load for single phase load conditions means
25% of rated current at rated phase voltage and unity power factor.
2.13.3
The deviation factor of the line-to-line voltage at zero load and at
balanced rated output capacity shall not exceed 10%. The RMS of all
harmonics shall be less than 5.0% and that of any one harmonic less than
3.0% of the fundamental at rated output capacity. Each engine-generator
shall be designed and configured to meet the total harmonic distortion
limits of IEEE Std 519.
2.14
EXCITER
The generator exciter shall be of the brushless type. Semiconductor
rectifiers shall have a minimum safety factor of 300% for peak inverse
voltage and forward current ratings for all operating conditions, including
110% generator output at 4O degrees C 104 degrees F ambient. The exciter
and regulator in combination shall maintain generator-output voltage within
the limits specified.
2.15
VOLTAGE REGULATOR
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NOTE: Delete reactive droop/differential
compensation for non-parallel configuration.
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Each generator shall be provided with a solid-state voltage regulator,
separate from the exciter. The regulator shall maintain the voltage within
a bandwidth of the rated voltage, over a steady-state load range of zero to
100% of rated output capacity. Regulator shall be configured for safe
manual adjustment of the engine-generator voltage output without special
tools, during operation, from 90 to 110% of the rated voltage over the
steady state load range of 0 to 100% of rated output capacity. Regulation
drift shall not exceed plus or minus 0.5% for an ambient temperature change
of 20 degrees C 68 degrees F. Reactive droop compensation or reactive
differential compensation shall load share the reactive load proportionally
between sets during parallel operation. The voltage regulator shall have a
maximum droop of 2% of rated voltage over a load range from 0 to 100% of
rated output capacity and automatically maintain the generator output
voltage within the specified operational bandwidth.
2.16
GENERATOR ISOLATION AND PROTECTION
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NOTE: Generator protection should be based on the
application and size of the generator and should
comply with the recommendations of IEEE Std 242 and
SECTION 16263A
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