Digital Excitation Control System (DECS-400)

The optional power system stabilizer function is an IEEE-type PSS2A, dual input, "integral of accelerating power" stabilizer that provides supplementary damping for low-frequency local mode, inter area, and inter unit power system oscillations.

Other features include:

• Five Control Modes, with autotracking between modes
  - Automatic Voltage Regulation (AVR)
  - Field Current Regulation (FCR)
  - Power Factor (PF)
  - Field Voltage Regulation (FVR)
  - Var Control
• 0.20% Voltage Regulation Accuracy
• Two pre-position set points for each mode
• Two Programmable Analog Outputs
• Setup from Front Panel HMI or by PC (local or remote)
• 40 Standard Stability Settings
• Time synchronization using IRIG or NTP (via Ethernet)
• Optional Integral Power System Stabilizer
  - Dual input, integral of accelerating power (IEEE PSS2A/2B)
  - Customer selectable speed-only sensing
  - Two wattmeter power measurement
  - Optional Frequency Based Operation
  - Generator or Motor control modes
• Customizable Stability Setting with two PID setting groups
• Reactive Droop, Line Drop Compensation
• Generator Voltage Soft-Start during Buildup
• Real Time Metering for 19 Generator Parameters
• Voltage Matching
• Autotracking with Optional Backup DECS-400
• Flexible Remote Set point Control
  - Contact inputs
  - Proportional Analog input, 10 Vdc or 4-20 mA
  - Digital Communications
• Local RS-232, ASCII, Modem Capabilities
• RS-485, Modbus™, RJ-45 Ethernet
• 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
• Setup and initial operation are facilitated by BESTCOMS, which offers:
  -real time monitoring test analysis
  -flexible oscillography, trending
  -expanded testing capabilities, including means for performing frequency response tests
• 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