BASLER DECS-200-2L Digital Excitation Control System

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