Basler Electric DECS-400 - Manual (Page 14)

2 9369700990 Rev R
o Generator undervoltage
o Generator overvoltage
o Loss of sensing voltage
o Generator frequency less than 10 hertz
o Loss of field (40Q)
o Field overtemperature
o Volts per hertz (24)
o Exciter diode failure
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IRIG time synchronization
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Sixteen contact inputs:
o Six fixed-function inputs: AVR, Manual, Lower, Raise, Start, and Stop
o Ten user-programmable inputs
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Eight contact outputs:
o Two fixed-function outputs: Watchdog, On/Off
o Six user-programmable outputs, configurable for maintained, latched, or momentary
operation
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Five communication ports:
o Front RS-232 port for interface with PC running BESTCOMS software
o Rear RS-485 port for dedicated communication with secondary, redundant DECS-400
o Rear RS-485 port using Modbus ™ protocol for communication with remote terminal
o Rear RJ-11 jack connects to onboard modem that provides dial-in and dial-out capability
o Rear RJ-45 jack provides Ethernet network communication
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Data logging, sequence of events recording, and trending
Generator Voltage Regulation
By utilizing digital signal processing and precise regulation algorithms, the DECS-400 regulates the
generator rms voltage to within 0.2% of the setpoint from no-load to full-load.
Control Output
The DECS-400 supplies an isolated control output signal of 4 to 20 mAdc, 0 to 10 Vdc, or
±10 Vdc to the
firing or control circuits of external power stages. The dc current produced by the power stages provides
excitation to the field of the generator, motor, or exciter. The DECS-400 can control virtually any bridge
that is capable of accepting these signals and is suitable for use on synchronous generators or motors.
Stability
PID (proportional + integral + derivative) stability control is utilized by the DECS-400. Preprogrammed
stability (PID) settings are provided for both main field and exciter field applications. A suitable, standard
stability set is available for most machines and applications. An additional, customizable setting group
provides optimum generator transient performance. A PID selection/calculation program supplied with the
DECS-400 assists in selecting the correct PID settings. Additional stability adjustments are provided for
customizing the stability and transient performance of the minimum and maximum excitation limiters and
the var/power factor controllers.
PID Setting Groups
The DECS-400 provides for two sets of PID settings to optimize performance under two distinct operating
conditions, such as with a power system stabilizer (PSS) in or out of service. A fast controller provides
optimum transient performance with the PSS in service, while a slower controller can provide improved
damping of first swing oscillations with the PSS offline.
General Information DECS-400