Basler DECS-400 Instruction manual - Features, Continued
DECS-400 Digital Excitation Control System
2
FEATURES, continued
DESCRIPTION
DECS-400 electrical and physical specifications are listed in the following paragraphs.
Operating Power
DECS-400 L:
24/48Vdc nominal (16-60Vdc), Burden=30W.
DECS-400 C:
120Vac nominal (85-132Vac, 50 or 60Hz), Burden=50VA.
125Vdc nominal (90-150Vdc), Burden=30W.
Generator Voltage Sensing
Single-phase or three-phase line voltage, two ranges:
• 100V/50Hz nominal (85-127Vac), 120V/60Hz nominal (94-153V)
• 200V/50Hz nominal (170-254Vac), 240V/60Hz nominal (187-305V)
Bus Voltage Sensing
Single-phase line voltage, two ranges:
• 100V/50Hz nominal (85-127V), 120V/60Hz (94 -153V)
• 200V/50Hz nominal (170 -254V), 240V/60Hz (187-305V)
SPECIFICATIONS
The DECS-400 Digital Excitation Control System is a
microprocessor-based controller that offers excitation
control, logic control, and optional power system sta-
bilization in an integrated package. The DECS-400 con-
trols field excitation by providing an analog signal used to
control the firing (output) of an external power bridge. The
DECS-400 monitors generator or motor parameters and
acts to control, limit, and protect the machine from operat-
ing outside its capability. The optional, onboard power
system stabilizer is an IEEE-defined PSS2A/2B, dual-input,
"integral of accelerating power" stabilizer that provides
supplementary damping for local mode, inter-unit and
inter-area power system oscillations.
APPLICATION
The DECS-400 is a digital excitation control system with optional Power System Stabilizer function that is used as the
primary controller in voltage regulator or main field excitation systems applied on a broad range of synchronous
generators or motors. The DECS-400 controls the generator output voltage, Var output or power factor by adjusting the
output of a semiconverter or full converter rectifier bridge that supplies DC power to the main or exciter field of the
generator. Because of its high level of flexibility and reliability, the DECS-400 is suitable for use in single or dual
controller systems on virtually any synchronous machine. The DECS-400 is at the heart of custom Basler Electric
excitation systems that typically include the digital controller, supplementary protective and control devices, a power
potential transformer and associated AC breaker or contactor, SCR firing circuits, and a power rectifier section, as-
sembled in suitable NEMA 1 excitation and power potential transformer enclosures.
• Built-in limiting functions
- Overexcitation Limiters - Summing Point or Takeover Type
- Underexcitation Limiters - 5 point user programmable or
internally generated, summing point or takeover
- Dual Slope Voltz/Hz Ratio or Underfrequency Limiter
- Stator Current Limiter (single phase or three phase)
• Built-in Protective Functions
- Field Overvoltage and Overcurrent
- Generator Undervoltage and Overvoltage
- Loss of Sensing Voltage
- Loss of Field (40Q)
- Field Overtemperature (for main field)
- Dual Slope Volts/Hertz (24)
- Exciter Diode Failure (for brushless exciters)
- Generator Frequency less than 10 Hz
• Sixteen Contact inputs - 10 user-programmable
• Eight Contact Outputs - 6 user-programmable
• Metering - Two 4-20mA meter drivers, customer programmable
• Four Communication Ports
• Data Logging, Sequence of Events Recording, Trending, real
time monitoring test analysis, and built-in frequency response test
capabilities
• UL Recognized, CSA certified, CE Compliant, GOST-R certified
per the relevant standards of Gosstandart of Russia, Byelorussian
certified
Integral programmable logic provides excitation system
control and annunciation based on DECS-400 contact
inputs, operating mode status, excitation system para-
meters and user-defined programming. Setup and initial
operation are facilitated by Basler Electric's user-friendly
BESTCOMS PC software that incorporates a test mode,
flexible oscillography, and a graphic display of PSS test
results.
The DECS-400 is designed for use with Basler's Interface
Firing Module (IFM) and semiconverter or full converter
power bridges. However, it will work equally well with any
power bridge with a firing circuit that is compatible with
the control signal output of the DECS-400.