Manual 02007
DSLC Digital Synchronizer and Load Control
Woodward
1
Chapter 1.
General Information
Introduction
This manual describes the Woodward DSLC™ Digital Synchronizer and Load
Control, both full and reduced function models (see Figure 1-1). The reduced
function models do not include the VAR/Power Factor Control or the Process
Control.
Application
The DSLC control is a microprocessor-based generator load control designed for
use with a Woodward speed control and an automatic voltage regulator to
provide synchronizing, paralleling, loading, and unloading of three-phase
generator sets. All transitions between DSLC functions are coordinated to
provide smooth operation.
DSLC functions include:
•
Selectable for phase matching or slip frequency synchronizing with voltage
matching and automatic dead bus closure capability;
•
Automatic generator loading and unloading for bumpless load transfer;
•
Droop, base load, and isochronous load control capability;
•
Process control for cogeneration, import/export, pressure control, or other
processes;
•
Isochronous load sharing with other sets equipped with DSLC controls;
•
VAR or power factor (PF) control (full function models only);
•
Built in diagnostics;
•
Multi-function adjustable high and low limit alarms and load switch with relay
driver outputs;
•
Digital communications network to provide load sharing, VAR/PF sharing,
and other information exchange between controls;
•
Full setup, metering, and diagnostic capability through a hand held
programmer terminal (Figure 1-2);
•
Reverse power relay.
Synchronizer
The DSLC control uses digital signal processing techniques to derive both true
RMS voltages and relative phase of the fundamental frequencies of the bus and
generator voltage wave forms. Digital signal processing techniques offer
significantly improved measurement accuracy in the presence of wave form
distortions, particularly since the phase measurement does not depend on zero
crossings of the wave forms.
Either phase matching or slip frequency synchronizing may be selected. Phase
matching provides rapid synchronizing for critical standby power applications.
Slip frequency synchronizing guarantees that initial power flow is out of the
machine for larger generators. For both synchronizing methods, the DSLC
control uses actual slip frequency and breaker delay values to anticipate a
minimum phase difference between bus and generator at actual breaker closure.