Basler Electric DECS-400 - Manual (Page 62)

50 9369700990 Rev R
Autotracking
The DECS-400 provides automatic tracking (following) of the controlling mode setpoint by the non-
controlling setpoint. When a primary and secondary DECS-400 are used together, the secondary DECS-
400 tracks the setpoint of the primary DECS-400.
Between DECS-400 Operating Modes
Autotracking between control modes of a DECS-400 enables an operator to initiate controlled, “bumpless”
transfers between operating modes with minimal disturbance to the power system. Autotracking enables
a set of protective relays to initiate a transfer to a backup mode (such as FCR mode) when a system
failure or fault (such as a loss of sensing) is detected.
Between DECS-400 Units
A DECS-400 controller can be placed in service as a backup to a primary DECS-400 controller. The
backup DECS-400 tracks the control output of the primary DECS-400 using dedicated communication
port Com 1. In the unlikely event of a primary DECS-400 failure, excitation control is transferred to the
secondary DECS-400 with minimal system disturbance.
Data Recording and Reporting
DECS-400 data recording and reporting functions include sequence of events recording (SER), data
logging, (oscillography), and trending.
Sequence of Events
A sequence of events recorder monitors the internal and external status of the DECS-400. Events are
scanned at 50 millisecond intervals with 127 events stored per record. All changes of state that occur
during each scan are time- and date-stamped. Sequence of events reports are available through
BESTCOMS. A sequence of events record can be triggered by a change in an alarm state, a relay output,
or contact input. All of the possible, user-selected state changes are listed below.
Alarm States
•
Clock Reset
•
Excessive Volts per Hertz
•
Failed to Build Up
•
Field Overcurrent
•
Field Overtemperature
•
Field Overvoltage
•
Generator Overvoltage
•
Generator Undervoltage
•
Loss of Field
•
Loss of Field Isolation Transducer
•
Loss of IRIG
•
Loss of Sensing Voltage
•
Open Exciter Diode
•
Overexcitation Limiting (OEL)
•
Power Supply Low
•
PSS Current Unbalanced
•
PSS Power Below Threshold
•
PSS Speed Failure
•
PSS Voltage Limit
•
PSS Voltage Unbalanced
•
Setpoint Lower Limit
•
Setpoint Upper Limit
•
Shorted Exciter Diode
•
Stator Current Limiting (SCL)
•
System Below 10 Hz
•
Underexcitation Limiting (UEL)
•
Underfrequency (V/Hz) Limit
Relay Outputs
•
Relay Output 1
•
Relay Output 2
•
Relay Output 3
•
Relay Output 4
•
Relay Output 5
•
Relay Output 6
•
Start/Stop
•
Watchdog
Contact Inputs
•
AVR (Auto)
•
FCR (Manual)
Functional Description DECS-400