Category: Basler Electric

Overview

The DECS-450 is a microprocessor based, high performance, extremely reliable

excitation controller for positive and positive/negative forcing excitation systems.

It supplies control voltage to an external bridge, which supplies dc energy to the

main or exciter field of a synchronous machine, making it compatible with any

size machine. The DECS-450 comes in many configurations to satisfy specific

requirements and redundancy needs. Basler offers customized and standard

solutions to fit a wide variety of applications.

Benefits

• With its high levels of flexibility and reliability, the DECS-450 is

suitable for virtually any synchronous machine.

• Reduce your setup time with Basler’s intuitive BESTCOMSPlus®

software that simplifies complex setup with simple drag-and-drop

programmable logic (BESTlogic™Plus), visual real-time strip chart

capabilities, and cutting edge auto PID selection capabilities.

• The revolutionary auto tuning function automatically establishes

optimum PID and gain settings, taking the guesswork out

of system setup, reducing commissioning time and cost

while maximizing overall system performance (Patent: US

2009/0195224 A1).

• Avoid costly generator damage and improve overall system

stability with an optional integrated PSS that utilizes the “integral

of accelerating power” to safely dampen local mode, inter-area, and

inter-unit power oscillations.

DESCRIPTION

The microprocessor based DECS-200 is a total excita

tion control system in one enclosure. It contains all the

functionality necessary to limit, control, and protect a

generator from operating outside of the machine’s

capability. A feature of DECS-200’s sophisticated

design allows the nonactive control mode within the

unit to follow the active mode, permitting bumpless

transfer between modes. The optional external tracking

feature also allows for unit-to-unit communication,

permitting autofollowing and transfer between DECS

200 units. It can also communicate to a PC via the front

panel RS-232 port for local programming and metering,

and it can communicate via Modbus™ protocol via the

side RS-485 port for communications up to 4000 feet

away from the DECS-200 unit. The DECS-200 has all

the features, functionality, flexibility and programmabil

ity expected from a state-of-the-art microprocessor

based product.

APPLICATIONS

The DECS-200 is an excitation control system used to control 

the output voltage, vars or power factor of a synchronous

generator by varying or controlling the amount of dc excitation

applied to the generator’s exciter field.

The DECS-200 is suitable for virtually any size machine.

One DECS-200 Digital Excitation Control System can accommodate 32Vdc, 63Vdc, or

125Vdc applications up to 15Adc. This unique flexibility provides precision control of

generators of virtually any size. The DECS-200 also incorporates a pulse width modulated

power stage, which improves system performances in non-linear load applications.

FEATURES

• Microprocessor-based design

• True RMS sensing, single or three phase

• 32Vdc, 63Vdc, and 125Vdc outputs at 15Adc

• 0.25% Voltage Regulation Accuracy

• Setup from front panel HMI or by PC with Windows® setup software included

• 20 standard stability selections

• User customizable stability selection

• Paralleling compensation

• Underfrequency compensation or V/Hz Ratio Limiter

• Soft start buildup

• Field Current Regulation Mode (Manual Mode)

• Autotracking between operating modes and between DECS-200 units

(optional)

• Minimum Excitation Limiter (Internally generated or customizable)

• On and off-line Maximum Excitation Limiters

• Stator Current Limiter

• Var and Power Factor Controllers

• Exciter Diode Monitoring (EDM)

• Sequence of Events Recording

• Oscillography

•Voltage Matching

•Eight (8) generator protection features

•Programmable output contacts

•Front panel backlit LCD display

•Front panel mounted RS-232 and side RS-485

communications ports

•Modbus™ protocol for RS-485 input allows

communications up to 4000 feet away

•<1% metering accuracy for 12 generator parameters

•Remote set point control via:

– Contact inputs

– Proportional control via ±10Vdc or 4-20mA

– Communications inputs RS-232 (ASCII) or RS-485(Modbus™)

•Meets C37.90.1-1989 for Surge Withstand and Fast Transient

•UL recognized, CSA certified, CE compliant, DNV certified,

GOST-R certified, Byelorussian certified

•U.S. Patent Number 5.294.879

The DECS-200N is a multi-microprocessor based Negative

Forcing Digital Excitation Control System designed into one

complete compact package. This space-saving design

consists of all the functionality needed to control, limit and

protect a generator from operating outside the machine’s

capability. This is accomplished by the DECS-200N’s

impressive control algorithm coupled with a versatile 20Adc

6 SCR power bridge. The input of the power bridge can be

fed by a 50 to 500 Hz, single or three phase voltage source,

depending on the desired excitation levels it is intended to

support.

DESCRIPTION

The DECS-200N also incoporates four control modes of

operation: Automatic Voltage Regulation (AVR), Field

Current Regulation (FCR, Manual), Volt Amp Reactive (Var)

and Power Factor (PF) control. In addition to these control

modes, the DECS-200N provides the ability for all non-active

control modes to follow the set point of the active mode,

permitting bumpless transfer between any other modes. For

applications requiring redundancy, the DECS-200N can

communicate unit-to-unit, allowing the backup DECS-200N

to automatically follow the active unit’s set point in the event

it is necessary to switch to the backup DECS-200N. Commu

nications with a PC is possible via a front panel RS-232 port

for local programming and metering. Provisions for remote

control are also available using contact inputs and the RS

485 port via Modbus protocol. The DECS-200N offers all of

the features, functionality, flexibility, and programmability for

use in new installations and in retrofit applications.

FEATURES

• Multiple microprocessor-based design

• True RMS sensing, single or three phase

• ±0.25% Voltage Regulation Accuracy

• 63 Vdc and 125 Vdc output capability up to 20 Adc continuous

• Built-in 6 SCR power bridge

• Negative field forcing

• Highly compact design

• High initial response

• Soft start buildup

• Var and Power Factor operating modes with Autotracking

• Autotracking between operating modes and between dual DECS-200Ns

• On and off-line Overexcitation Limiter

• Customizable Underexcitation Limiter

• Stator Current Limiting

• Underfrequency compensation or V/Hz Ratio Limiter

• Field flashing control provisions

• Paralleling provisions

• Generator Protection

• Exciter Diode Monitoring (EDM)

• Oscillography and Sequence of Events Recording

• Voltage Matching

• 5 Programmable output contacts

• Modbus™ protocol via RS-485 communications

The DECS-200N is a very compact Negative Forcing Digital Excitation Control System.

This compact design accommodates 63 Vdc and 125 Vdc applications up to 20 Adc

continuously. The on-board six-thyristor controlled rectifier bridge offers the highest

system performance possible, making the DECS-200N ideal for providing exceptional

system response, which makes it suitable for applications requiring power system

stabilizers.

APPLICATION

The DECS-200N is a highly responsive negative forcing excitation

control system used to control the output voltage, vars, or power

factor of a synchronous generator by automatically adjusting the

amount of dc excitation being applied to the generator’s exciter field.

Due to its negative forcing capabilities, the DECS-200N is ideal for

virtually any size system that demands exceptional system response

and/or requires Power System Stabilizers.

Functional Description

ECM-2 performs functions previously performed in ECS2100 systems by three, separate modules:

Sensor Input Module (SIM), Exciter Control Module (ECM), and Firing Control Interface Module (FCIM).

The functionality of these modules has been retained with some enhancements.

Sensor Inputs

Twenty-four, high-speed analog inputs (channels) collect data (sensing values) from the generator PTs

and CTs and other analog signal sources through hard-wired inputs. Fiber-optic connections receive

digital signals supplied by the DECS-2100 system Digital I/O Modules. Analog and temperature signals

supplied by the DECS-2100 system Analog I/O Modules are also received through fiber-optic connections

on the isolation transducer card interface. Analog inputs are digitized and provided to the excitation

circuitry for interpretation.

Power Bridge Firing Interface

This portion of the ECM-2 module provides SCR firing commands to the DECS-2100 system Bridge

Control Modules. In turn, each Bridge Control Module controls the level of dc output power supplied by

the corresponding power bridge. Power bridge output is determined by a control signal supplied from the

excitation control circuitry to the firing control logic. To generate the SCR firing signals, the firing control

circuitry creates timing signals that are time- and pattern-synchronized with the monitored, three-phase

PPT voltage. (The PPT voltage is monitored by way of an Isolation Transducer connected to the ECM-2

module’s PPT fiber-optic input.) The firing signals, interspersed with data signals, are transmitted to the

DECS-2100 system Bridge Control Modules via fiber-optic connections.

In its standard configuration, the ECM-2 module can control from one to four sets of Bridge Control

Modules and power bridges. In its optional configuration, up to 16 sets of Bridge Control Modules and

power bridges can be controlled.

In addition to power bridge control, this circuitry processes power bridge alarms received from the Bridge

Control Modules and provides the alarm data to the excitation control logic. Processed alarms include

SCR loss, high power bridge temperature, and low power bridge temperature.

Introduction

The ECM-2 Excitation Control Module provides the core functions of regulation, input sensing, and

thyristor firing control in a DECS-2100 Digital Excitation Control System. Functions previously provided by

three separate circuit boards in ECS2100 systems are now provided by one compact module. The ECM-2

replaces the Sensor Input Module (SIM), Exciter Control Module (ECM), and Firing Control Interface

Module (FCIM) previously used in ECS2100 systems.

ECM-2 advantages include:

• Fully-enclosed package provides protection of key system circuitry

• Previously-required space for three, separate circuit boards is reduced to one compact module

• The proven reliability of the ECS2100 system design with added functionality:

o Improved thyristor firing accuracy

o Increased number of analog inputs from 12 to 24

o Standard ECM-2 hardware configuration supports up to four power bridges via fiber optic

communications. The expanded fiber optic version can accommodate up to 16 power bridges

o Expanded event recording and data logging capability

o Additional USB port accepts removable storage media for downloading events, data logs,

and alarm logs without the use of a computer

o Cross-current compensation between excitation systems through a built-in communication via

RJ-45 port over Ethernet

o IRIG-B and NTP time synchronization provides synchronized data recording.

o Additional RJ-45. 10BASE-T/100BASE-TX Ethernet port for a dedicated control network

protocol

This relay monitors the voltages on both sides of a circuit breaker and

determines the existence of proper phase angle and voltage before

allowing the breaker to close.

Product Features & Benefits

• Accurate, repeatable, and reliable operation.

• Minimized PT costs as a result of low sensing burden.

• Reduced battery load with low burden power supply.

• Simple HMI provides clear and intuitive settings for easy configuration

without the use of a computer.

• Integrated voltage monitor provides complete supervision for conditions

such as dead bus, where sync-check alone is not sufficient to supervise

the breaker closing.

• LED indicators provide clear annunciation of status.

• Easily perform in-case system and device tests using test paddles.