Category: Woodward

Synchronizer

The MSLC uses digital signal processing techniques to derive both true RMS

voltages and relative phase angles of the fundamental frequencies of the utility

and the local bus 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 voltage 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 ensures that the initial flow of power will be either

out of the local system (export) or into the local system (import), depending on

whether a positive or negative slip is chosen. For both synchronizing methods,

the MSLC uses actual slip frequency and breaker delay values to anticipate an

adjustable minimum phase difference between the utility and the local bus.

Additional synchronizer functions include voltage matching, time delayed

automatic multi-shot reclosing, auto-resynchronizing, and a synchronizer timeout

alarm. Each of these features may be enabled or disabled during setup.

Introduction 
This manual describes the Woodward MSLC Master Synchronizer and Load Control. 
Application
The MSLC is a microprocessor-based overall plant load control designed for use 
in a system with Woodward DSLC™ (Digital Synchronizer and Load Control) 
controls on each generator to provide utility synchronizing, paralleling, loading, 
and unloading of a three-phase generating system. 

MSLC functions include: 
 Selectable for phase matching or slip frequency synchronizing between the 
utility and a local bus with voltage matching; 
 Automatic system loading and unloading for bumpless load transfer; 
 Import/Export level control capability; 
 Process control for cogeneration, pressure, maintenance, or other process; 
 Proportional loading of associated DSLC controls in isochronous load sharing; 
 Adjustable Power Factor control; 
 Built in diagnostics with alarm relay driver output; 
 Multi-function adjustable high and low limit alarms and adjustable load 
switches with relay driver outputs; 
 Digital communications network to provide loading and power factor control 
of individual DSLC equipped generators; 
 Full setup, metering, and diagnostic capability through a hand held 
programmer terminal (Figure 1-2). 

MSLC functions include: 
 Selectable for phase matching or slip frequency synchronizing between the 
utility and a local bus with voltage matching; 
 Automatic system loading and unloading for bumpless load transfer; 
 Import/Export level control capability; 
 Process control for cogeneration, pressure, maintenance, or other process; 
 Proportional loading of associated DSLC controls in isochronous load sharing; 
 Adjustable Power Factor control; 
 Built in diagnostics with alarm relay driver output; 
 Multi-function adjustable high and low limit alarms and adjustable load 
switches with relay driver outputs; 
 Digital communications network to provide loading and power factor control 
of individual DSLC equipped generators; 
 Full setup, metering, and diagnostic capability through a hand held 
programmer terminal (Figure 1-2). 

ADJUSTMENTS

The Woodward Hand Held Programmer makes all

adjustments quickly and easily, through the control’s ten

convenient “menus”.  The control saves all set points in

permanent memory, which does not require batteries or

other power sources to retain data.  The Hand Held

Programmer prevents tampering with set points, yet allows

entries to be changed at any time.

• Menu 1 – Synchronizer Functions

• Menu 2 – Load Control Functions

• Menu 3 – Process Control Functions

• Menu 4 – VAR/Power Factor Control Functions

• Menu 5 – Configuration

• Menu 6 – Calibration

• Menu 7 – Generator Electric Parameters

• Menu 8 – Control Status Monitor

• Menu 9 – Discrete Inputs/Outputs Monitor

• Menu 0 – Diagnostics

OPERATING MODES

Isolated Bus — The DSLC talks over its LON to share

proportional real and reactive loads.  Real load (kW) is

controlled using percentages of full load for each machine,

and reactive loads (kVAR) are

shared by matching power factors.

The DSLC maintains a specified

bus voltage and frequency while

balancing loads.

Utility Parallel — The DSLC

measures real load (kW) on the

generator and adjusts the speed

control to match a set base load, to

control a process at a user-chosen,

externally adjustable setpoint.  Or it

can set a constant import/export

level using an MSLC ( Master

Synchronizer and Load Control).

The DSLC can also measure and

maintain a set reactive load (kVAR)

or can maintain a user-prescribed

power factor.

Transition Between Modes — The

DSLC will ramp at a user-chosen

rate from one mode to another

until the control is within 5% of its

target. It then shifts into dynamic

control, allowing bumpless

operating mode changes. In

addition, the DSLC automatically

changes its VAR/PF mode when

the real load mode is changed to or

from an isolated bus, load sharing

mode. Manual VAR/PF control

may also be selected.

ADVANTAGES

• Reduces wiring between synchronizer, load

control and automatic loading controls

• Having functions integrated into one box

eliminates the need for redundant sensors

(like PTs, CTs and MOPs) that connect to

individual modules such as the load sensor and synchronizer

• Hand Held Programmer reduces installation

and calibration time by allowing the user to

set up the control prior to starting the system

• Hand Held Programmer lets operator monitor generator

parameters, contact switches, and analog I/O for

installation and troubleshooting

• Reduces the amount of cabinet space needed

• Eliminates the need for additional relay logic or a PLC to

control dead bus closing

• Digital communications across the LAN reduce

susceptibility to noise on the load sharing lines

• Slip frequency paralleling, voltage matching, and speed

bias hand-off between the synchronizer and load control

result in smooth paralleling without the risk of reverse power trips

• Three-phase true rms power sensing makes the DSLC

accurate even with unbalanced phase loading and voltage fluctuations

• Can load share with Woodward analog controls when

used with the Load Sharing Interface Module. Refer to

Woodward Manual # 02031 for details.

APPLICATION

The Woodward DSLCTM control is a

microprocessor-based synchronizer and load

control designed for use on three-phase AC

generators equipped with Woodward or other

compatible speed controls and compatible

automatic voltage regulators. The DSLC is a

synchronizer, a load sensor, a load control, a

dead bus closing system, and optionally a

VAR/PF and process control, all integrated

into one powerful, yet convenient package.

The DSLC control provides either phase

matching or slip frequency automatic

synchronizing. The DSLC talks over its own

LON (using Echelon®  LonWorks™* network

technology) to enable safe dead bus closing,

and ties into your automatic voltage regulator

to match voltages before paralleling.

The DSLC control senses true rms power and

provides bumpless loading and unloading

functions.  It can either base load or set

import/export/process power levels against the

utility, and through the DSLC’s LON,

accurately share loads on isolated, multi-engine

systems.

The optional VAR/PF control is flexible

enough to allow you either to provide a set

level of VARs to the utility (if this is

economical) or to maintain a constant power

factor for reliable operation.  Through the

LON, the VAR/PF control also shares power

factors in isolated systems, maintaining

proportional reactive loads (kVARs) on all

machines more accurately than droop or cross

current voltage systems.

General:

The DSLC-2XT/MSLC-2XT is an upward compatible successor device for the DSLC-2/MSLC-2.

They are based on the easYgen-3400XT-P2 hardware. It is designed to function

as good as the original DSLC2/MSLC-2 (version 1.1511).

The new generation is equipped with a more powerful CPU, memory, and communication.

It is more responsive in HMI and SCADA communications.

The important control functions run on the same task rates that ensures the same control dynamic.

Most important, it is being designed to be able to run with the legacy DSLC-2/MSLC-2 system.

This becomes more important than ever due to lack of obtainable components that may

force us to make a hard stop to the DSLC-2/MSLC-2 product line later this year.

If some minor rules are observed the DSLC-2XT can be mixed with already existing DSLC-2 / MSLC-2 in an

application.

MSLC-2XT (in line with DSLC-2XT) is also in preparation and comes few months after DSLC-2XT.

Others:

The communication 9-pin D-sub connectors are replaced by phoenix plugs with screw terminals

The analog outputs 1 & 2 are supported with two terminals now (the shunt for voltage output is internally

populated)

Schedule:

DSLC-2XT: Design release to production scheduled for Sept’22.

Shipment expected Oct’22 however depends on availability of components.

Limited early sample and draft manual available. Please contact your account manager.

MSLC-2XT: Design release to production scheduled for Nov’22.

Shipment expected Dec’22 however depends on availability of components.

Limited early sample and draft manual available. Please contact your account manager.

Part Numbers:

8440-2298: MSLC-2XT

8440-2299: DSLC-2XT

Important Considerations:

Communicating with legacy DSLC-2 (and MSLC-2)

Woodward will provide update files for legacy DSLC-2 and MSLC-2 devices in the field if

there is to run a mix of both DSLC-2/MSLC-2 generations. 

The legacy device will then send their UDP messages in a way that DSLC-2XT/MSLC-2XT can evaluate.

It is mandatory to load this update file into the legacy devices for the system to run smoothly.

2. Using your existing settings file (*. WSET) from legacy DSLC-2 (and MSLC-2)

Woodward will provide a conversion rule for ToolKit to make the configuration transfer as smooth as

possible.

Some minor parameters will be shown in a log file, to be evaluated manually.

3. The AC measurement of the DSLC-2XT (and MSLC-2XT)

The measurement hardware and software are different in comparison to the legacy devices.

This is mainly due to higher accuracy, more flexible measurement range and fast response characteristics.

The earthing of the DSLC-2XT/MSLC-2XT devices has become more important due to higher impedance

of the measurement circuits.

4.ToolKit

To give you a seamless transition experience, the ToolKit layout (*. WTOOL file) is designed like the

original devices.

There are few less parameters due to new AC measurement and communication interfaces.

5.Documentation server

Product literature (manuals, config. files, software etc.) is hosted on a documentation server

that is easily accessible by a QR code printed on the housing. 

Two additional QR stickers are delivered with the controllers to help you paste them at a location

convenient to you.

Subsequently, product CD is removed from scope of delivery.

.Woodward understands the time-intensive nature of Power Generation projects.

Ensuring the longevity of our products is one way we make our customers successful.

Woodward has supplied and supported the field proven MSLC-2/DSLC-2 line of 

synchronizers and load controllers for over a decade.

An upcoming state of the art Drop-In replacement successor extends the life cycle of this product line for

another decade and possibly beyond. This document provides an overview of what to expect from the

successor products,namely MSLC-2XT/DSLC-2XT respectively.

Important Features:

→  Drop-In Replacement (Mounting dimensions and overall dimensions are same)

→  Similar Look and Feel as MSLC-2/DSLC-2 (available in back panel mounting style)

→  USB Connectivity to PC (RS-232 port is removed; new: USB Type B)

→  Direct connect up to 690VAC (increased range handled by device configuration)

→  Software selectable 1A/5A CT input (supported by one P/N)