DSLC Digital Synchronizer and Load Control
Manual 02007
66
Woodward
Chapter 5.
Real Power Control Description
Introduction
The DSLC™ control provides several modes of generator load operation. These
are:
•
isochronous load sharing;
•
system bus parallel or isolated unit droop based on real power;
•
system bus parallel base loading;
•
process controlled generator load.
Base Load operation controls generator set real power, which in integrating
mode is independent of variations in bus frequency. With the VAR/Power Factor
control, reactive power may also be controlled independent of bus voltage
variations.
Automatic ramping functions provide bumpless transfer of load when adding or
removing generator capacity to a system or changing the mode of load control
operation.
Power Sensor Theory of Operation
The digital signal processing (DSP) power measurement technique used by the
DSLC 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.
The average power measured over an interval of n samples is given by
where Vi and Ii are simultaneous samples of voltage and current equally spaced
in time. The average power in the three phase system is the sum of the power in
each phase.