9440300990 Rev J vii
DECS-250 Contents
Stator Current Limiter..............................................................................................................................63
Low-Level Limiting...............................................................................................................................63
High-Level Limiting ..............................................................................................................................63
Initial Delay ..........................................................................................................................................63
Var Limiter ...............................................................................................................................................64
Limiter Scaling.........................................................................................................................................64
Underfrequency Limiter...........................................................................................................................65
Volts per Hertz.....................................................................................................................................66
Metering .....................................................................................................................................................69
Metering Explorer....................................................................................................................................69
HMI ......................................................................................................................................................69
BESTCOMSPlus®................................................................................................................................69
Metered Parameters................................................................................................................................70
Generator.............................................................................................................................................70
Power...................................................................................................................................................70
Bus.......................................................................................................................................................71
Field .....................................................................................................................................................72
PSS......................................................................................................................................................72
Synchronization ...................................................................................................................................73
Auxiliary Control Input..........................................................................................................................73
Tracking...............................................................................................................................................73
Control Panel.......................................................................................................................................74
Metering Summary...............................................................................................................................75
Status Indication......................................................................................................................................76
System Status......................................................................................................................................76
Inputs ...................................................................................................................................................77
Outputs ................................................................................................................................................78
Network Load Share............................................................................................................................79
Configurable Protection .......................................................................................................................79
Alarms..................................................................................................................................................80
Real-Time Clock ..................................................................................................................................83
Auto Export Metering...............................................................................................................................84
Event Recorder..........................................................................................................................................85
Sequence-of-Events Recording ..............................................................................................................85
Data Logging...........................................................................................................................................85
Setup....................................................................................................................................................86
Triggers................................................................................................................................................86
Trending ..................................................................................................................................................89
Power System Stabilizer...........................................................................................................................91
Supervisory Function and Setting Groups...............................................................................................91
Supervisory Function...........................................................................................................................91
Setting Groups.....................................................................................................................................91
Theory of Operation.................................................................................................................................91
Speed Signal........................................................................................................................................93
Rotor Frequency Calculation...............................................................................................................93
Generator Electrical Power Signal.......................................................................................................93
Derived Mechanical Power Signal.......................................................................................................94
Stabilizing Signal Selection..................................................................................................................94
Torsional Filters ...................................................................................................................................95
Phase Compensation ..........................................................................................................................95
Washout Filter and Logic Limiter.........................................................................................................95
Output Stage........................................................................................................................................96
Terminal Voltage Limiter......................................................................................................................96
Stability Tuning .......................................................................................................................................101
AVR Mode .............................................................................................................................................101
Predefined Stability Settings..............................................................................................................101
