EGCP-2 Engine Generator Control Package Manual 26086
70 Woodward
NOTE
It is highly recommended that the automatic reactive load control in the
EGCP-2 be used for proper power conditioning throughout the generator(s)
load range. This is achieved by setting the Load Control setpoint in the
Configuration tuning menu to Normal, or Soft Transfer (depending on the
application), and the VAR/PF Control setpoint in the Reactive Load Control
tuning menu to VAR or PF control (depending on the application). For more
details on these functions see the Real Load Control and Reactive Load
Control sections of this manual.
The percent level of the voltage bias output can be monitored in the I/O Display
status screen of the EGCP-2. This is a useful point to monitor during initial start
of the unit. By issuing Voltage Raise and Lower inputs to the control while
operating in the Test Mode, confirmation of proper generator voltage levels at
various voltage bias points can easily be made. Typically the generator voltage
should change no more than ±10% for a ±100% voltage bias output from the
EGCP-2.
All other modes of generator set operation rely upon the Reactive Load Control
functions of the EGCP-2. See the information in the “Reactive Load Control”
section of the manual for more details on voltage and reactive load control.
Generator Load Control
Power Sensor Theory of Operation
The digital signal processing (DSP) power measurement technique used by the
EGCP-2 control involves periodic sampling of the voltage and current over an
integral number of wave forms. The microprocessor computes the product of the
voltage and current samples, then sums and averages the products to give a
computation of power.
Load Sensor Hardware Description
The digital load sensor gets timing information from the generator A phase
voltage signal. Voltages proportional to the voltage and load current for each
phase are routed to the sample-and-hold circuits of the A/D converters. The
simultaneous sampled values representing voltage and current are held when a
conversion-store signal is received from the microprocessor. Each input is then
converted and an interrupt is generated when all inputs are converted. The
microprocessor then reads the digital values from A/D registers. This procedure
is repeated at regular intervals to provide input for further signal processing.
To provide accuracy in the presence of noise and harmonics on the inputs,
multiple samples of each wave form over a number of cycles of the input are
taken to get the power measurement.
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