WOODWARD DSLC-2 Digital Synchronizer and Load Control

WOODWARD DSLC-2 Digital Synchronizer and Load Control

Introduction

The Woodward DSLC-2 digital synchronizer and load control is an advanced microcomputer control device designed specifically for three-phase AC generators, integrating multiple functions such as synchronization control, load sensing, load distribution, dead bus closure, reactive power/power factor control, and process control. This article is based on Woodward's official 37443J technical manual (software version 1.15xx), providing a comprehensive analysis of the core functions, technical features, installation configuration, and operational applications of the device. The aim is to provide engineers, technicians, and operations personnel with a detailed reference guide.

1、 Product Overview and Core Features

1.1 Product positioning

DSLC-2 is a direct upgrade product of Woodward's classic DSLC series, suitable for various grid connected or islanded operating generator sets. Its design supports parallel operation and control of up to 32 generator sets, achieving seamless communication between DSLC-2 and MSLC-2 (main station load control unit) through a dedicated Ethernet system.

1.2 Main functional modules

Synchronizer function:

Supports two modes: phase matching or slip frequency synchronization.

Capable of automatic dead bus closure, conducting locking negotiation through communication network to prevent multiple devices from closing simultaneously.

Integrated voltage matching, automatic reclosing, automatic resynchronization, and synchronization timeout alarm functions.

Load control function:

Support droop control, base load control, and equal power load distribution mode.

Provide adjustable ramp loading/unloading to achieve disturbance free switching.

Integrated reverse power protection, load switch, and frequency fine-tuning functions.

Process control function:

Cascade PID process controller, suitable for applications such as cogeneration, inlet/outlet control, pressure or liquid level control, etc.

Supports analog input (process signal) and internal digital reference, and can be remotely set.

Reactive power/power factor control function:

Control the reactive power or power factor of the generator in the grid connected system.

Support reactive power sharing (during islanding operation) and voltage fine-tuning function.

Provide voltage range alarm and high/low limit protection.

Communication and network functions:

Equipped with dual Ethernet ports (network A and B), supporting redundant communication.

Network A is dedicated to DSLC-2/MSLC-2 internal communication (UDP protocol).

Network B supports Modbus TCP/IP for communication with the upper computer (PLC/DCS).

Additionally, RS-485 interface is provided to support Modbus RTU protocol.

2、 System architecture and installation points

2.1 Hardware Installation

Dimensions: 227 mm × 250 mm × 84 mm, using panel installation method.

Environmental requirements: The working temperature range is -40 ° C to+70 ° C, and direct exposure to water sources, condensation environments, and strong electromagnetic interference should be avoided.

Power requirement: 12/24 VDC (range 8-40 VDC), it is recommended to use slow melting fuses (6A) or miniature circuit breakers for protection.

Grounding protection: It is necessary to connect a protective earth wire (PE) with a wire diameter of not less than 2.5 mm ².

2.2 Wiring specifications

Voltage measurement:

Generator voltage measurement supports 3-phase 4-wire (with neutral point), 3-phase 3-wire, and 3-phase 4-wire open delta connections.

Bus voltage measurement supports 1-phase 2-wire (phase to phase or phase to neutral point) and 3-phase measurement of auxiliary bus.

Attention: 120V and 480V input terminals cannot be used simultaneously, and the correct terminals should be configured according to the rated voltage of the PT secondary side.

Current measurement:

Support three-phase or single-phase current transformer input, ensuring that one end of the CT secondary side is grounded.

When wiring, attention should be paid to the power measurement direction and display symbol (positive for power generation, negative for reverse power).

Discrete input:

Supports positive or negative polarity signals, but all inputs must be of the same polarity.

The input functions include: operation, circuit breaker assistance, voltage rise/fall, load rise/fall, base load, unloading, process control, ramp pause, and section number selection.

Relay output:

There are a total of 12 relay outputs, including alarm, load switch, high and low limit, circuit breaker opening and closing, and voltage rise/fall.

The output contact capacity is 250VAC/DC, 2A.

Analog input/output:

Provide 3 analog inputs (remote load reference, process signal, reactive load).

2-channel analog output (speed bias, voltage bias), supporting multiple signal types such as 0-20mA, 4-20mA, 0-10V, etc., can be configured as voltage or PWM output through jumper wires.

2.3 Communication Interface

RS-232: Used to connect Woodward ToolKit configuration software.

RS-485: Supports Modbus RTU half duplex or full duplex communication.

Ethernet (RJ-45): Network A (UDP+Modbus TCP), Network B (Modbus TCP, optional redundant UDP).