Basler ElectricDECS-200-1C Digital Excitation Control System

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

FEATURES, continued

• 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

DESCRIPTION

The microprocessor based DECS-200 is a total excitation 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 DECS200 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 programmability 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

SPECIFICATIONS, continued

Generator Current Sensing Two ac current sensing ranges and two channel (phase) inputs:

• For metering and control: 1A and 5A.

• For cross current compensation: 1A and 5A.

Sensing Burden Voltage: Less than 1VA per phase.

Current: Less than 1VA.

Parallel Compensation: Less than 1VA.

Contact Switching Inputs 11 contact switching inputs are supplied with 24Vdc to accommodate dry

contacts. Contacts are as follows:

• Start • Var/PF Enable

• Stop • Pre-position

• Secondary DECS Enabled (optional) • Raise Switch

• Unit/Parallel Operation • Lower Switch

• AVR Mode • Alarm Rest

• FCR Mode

Remote Set Point Control Two separate analog inputs for remote set point control. Typically used to accept

(Accessory Input) a signal from a Power System Stabilizer. Select one from the configuration menu.

• ±10Vdc

• 4 to 20 milliamperes

COMMUNICATION There are three communication ports, two RS-232 and one RS-485: COM0: RS-232, 9 pin, sub-D connector located on front panel and used to communicate with local computers. 1200 to 19200 baud, 8N1 full duplex, ASCII commands COM1: RS-232, 9 pin, sub-D connector located on right side panel and used to connect primary and backup DECS-200 units. Port is only used for optional autotracking. COM2: RS-485, located on left side panel and used to communicate with local or remote computers or other devices. 1200 to 19200 baud, 8N1 half duplex, Modbus™ protocol

SPECIFICATIONS, continued

REGULATION ACCURACY

AVR Mode: Voltage regulation equals ±0.25% over the load range at rated power factor and constant

generator frequency. Steady state stability equals ±0.1% at a constant load and generator frequency.

Temperature drift equals ±0.5% for 0 to 50°C temperature change. Underfrequency (volts/hertz)

characteristic slope from 0 to 3.0 P.U. is adjustable in 0.1 P.U. increments.

FCR Mode: Field current regulation equals ±1.0% of the nominal value for 10% of the bridge input voltage

change or 20% of the field resistance change.

var Mode: ±2.0% of the nominal VA rating at the rated frequency.

PF Mode: ±0.02 PF in the set point PF for the real power between 10 and 100% at the rated frequency.