BASLER DECS-200-2L Digital Excitation Control System

BASLER DECS-200-2L Digital Excitation Control System DECS2002L

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.

• 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

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

DECS-200-1C

DECS-200-1L

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.

(e.g. -set point PF=0.80, PF regulation is from 0.78 to 0.82 PF.)

Internal autotracking(optional): ±0.5% of the nominal field voltage change when transferring.

PARALLEL COMPENSATION Can use either reactive droop or reactive differential (cross-current) compensation.

Adjustable from 0 to 30% of the rated generator voltage droop with optional 1 ampere or less or 5 amperes

or less input. Line drop compensation uses this same parameter; however, it is adjustable from -30% to 0.

FIELD OVERVOLTAGE PROTECTION Adjustable in increments of 1.0Vdc from 1.0 to 325Vdc rated output

voltage with a 0.2 to a 0.2 to 30 second inverse time delay settable in increments of 0.1 second.

FIELD OVERCURRENT PROTECTION Adjustable in increments of 0.1Adc steps of rated field current from 0 to

16Adc excitation current setting with an inverse time delay (ANSI C50.13).

EXCITER DIODE MONITOR (EDM) The DECS-200's EDM can detect open and shorted diodes on brushless

generators. To do this, the DECS-200 requires the user to input the number of generator poles and the number of

exciter poles (both adjustable from 0 to 20 in increments of 2). The open and shorted diode ripple threshold is

adjustable from 0 to 100% of field current. The open diode protection time delay is adjustable from 10 to 60

seconds, and the shorted diode protection time delay is adjustable from 5 to 30 seconds.

GENERATOR UNDERVOLTAGE PROTECTION Adjustable in increments of 1Vac from 0 to 30kV sensing voltage

setting with a 0.5 to 60 second time delay (ANSI C50.13) settable in increments of 0.1 sec.

GENERATOR OVERVOLTAGE PROTECTION Adjustable in increments of 1Vac from 0 to 30kV sensing voltage

with a 0.1 to 60 second time delay (ANSI C50.13) settable in increments of 0.1 second.

GENERATOR LOSS OF FIELD PROTECTION Adjustable in increments of 1 kVar from 0 to 3,000Mvar, with a

0.1 to 9.9 second delay settable in increments of 0.1 second.

LOSS OF SENSING The loss of sensing setting for both balanced and unbalanced generator voltage is adjustable

from 0 to 100% of nominal generator voltage. The protection delay is adjustable from 0 to 30 seconds in 0.1

increments.

SOFT START Functional in AVR and FCR with an adjustable rate of 1 to 7200 seconds in one second increments.

Voltage Regulation

The DECS-200 regulates the generator RMS voltage to within

0.25% from no-load to full-load. It does this by utilizing digital

signal processing and precise regulation algorithms developed

by Basler Electric, utilizing the experience gained in many years

of manufacturing tens of thousands of digital voltage regulators.

Stability

The DECS-200 utilizes proportional (P), integral (I) and derivative

(D) stability control. DECS-200 has 20 preprogrammed stability

(PID) settings for exciter field applications. This means that a

standard stability setting is already available for most applications/

machines. The DECS-200 has a stability range that allows

for customizing the stability settings to fine tune the stability to

provide optimum customized generator transient performance.

Setup software contains PID selection program to assist in

determining the correct PID settings. The DECS-200 provides for

customizing the stability and transient performance of the Min/

Max Excitation Limiter and var/PF controllers by providing

additional stability adjustments.

Underfrequency Limiter or V/Hz Ratio Limiter

DECS-200 is selectable for either Underfrequency Limiter or a

V/Hz Ratio Limiter function. The underfrequency limiter slope can

be tuned to have 0 to 3 times p.u. Volts/Hz, in 0.1Hz increments,

and the corner frequency roll-off point can be set across a range

of 45 to 65Hz, in 0.1Hz increments. This adjustability allows the

DECS-200 to precisely match the operating characteristics of the

prime mover and the loads being applied to the generator. The

Volts/Hz Ratio Limiter clamps the regulation set point to prevent

operation above a V/Hz level that is prescribed by the slope of the

DECS-200. This feature is also useful for other potentially

damaging system conditions such as a change in system voltage

and re-duced frequency situations that exceed the V/Hz ratio.

Soft Start Voltage Buildup

Generator voltage overshoot can be harmful to the generator's

insulation system if not controlled. DECS-200 has a soft start

feature with a user-adjustable setting to govern the rate at which

the generator voltage is allowed to build up. This reduces the

amount of generator voltage overshoot form nominal operating

voltage during start-up of the generator system.

Paralleling Compensation

DECS-200 has provisions to parallel two or more generators

using reactive droop or reactive differential compensation with

the addition of an external current transformer with secondary

currents of 1 or 5Aac. The current input is rated at less than 1VA.

This low burden means that existing metering CTs can be used

and dedicated CTs are not required.

Set Point Control

DECS-200 has means for external set point adjustment of the

controlling mode of operation. This eliminates the need for

additional equipment like motor operated potentiometers for

remote control or multiple point control for the excitation system.

The operating mode's set point may be directly controlled by

raise/lower contact inputs or auxiliary inputs of 4-20mA or

±10Vdc. The auxiliary input adjusts the operating mode across its

predetermined adjustment range. The auxiliary input can be

provided from other controlling devices such as a power

system stabilizer. These devices modify the operation of the

DECS-200 to meet specific operating characteristics and requirements

for the machine under DECS-200 control. Two more

methods of set point control may be achieved via the RS-232

communication port by using the Windows® based PC software

or by the RS-485 port using Modbus™ protocol. Regardless of

which method of set point is used (contact inputs, auxiliary input

or communications with a PC or PLC), traverse rates of all modes

of operation are independently adjustable. This means an

operator can customize the rate of adjustment and "feel" to meet

his/her needs.