Generator Excitation Systems and Voltage Regulators

Features of the new digital static excitation and voltage regulator interface include data logging (oscillography), sequence of events recording and real-time dynamic system analyzers. These can be set up and accessed easily by a laptop and greatly aid in system testing and troubleshooting of problems, such as those caused by system disturbances. We can now record the performance of the system both before and after any system disturbance.

  • Generator Voltage Soft Start that will prevent voltage overshoot during machine startup
  • Automatic Nulling to prevent bumps in voltage and vars when transferring between an automatic voltage regulator and manual field current control
  • Automatic Voltage Matching between the generator and the bus voltage to prevent var exchange/bumps when paralleling
  • Insulation Integrity Testing comprising of: Polarization Index (PI), dc leakage testing, dc hipot and ac hipot testing for generator stators and rotors
  • Var/Power Factor Controller if var regulation or power factor control is needed within this generating system, selectable by the operator whenever it is needed
  • Summing-Point Type or Takeover Type Offline & Online Maximum Excitation Limiting to prevent rotor damage due to excessively long over excitation periods
  • Underexcitation Limiting to prevent too little excitation to be applied into the field based upon the kWs being exported
  • Stator Current Limiting to prevent sustained overheating of the Stator Windings
  • Generator Protection including loss of field, under/overvoltage, field overcurrent, field overvoltage, field overtemperature, and loss of PT voltage sensing, volts per hertz
  • Underfrequency or selectable Volts/Hertz Ratio Limiting to prevent the machine from being overfluxed at a low operating frequency
  • Improved Voltage Regulator Response If tuned properly, the present analog system might be able to provide about a 1.5 second reaction time to a voltage step change. The new digital system can be tuned to respond in less than 0.5 seconds
  • Modbus® Communication Port available to interface to existing plant DCS systems for both control and monitoring of the new digital control system. As an option, the Modbus® Communication Port could be connected directly to a remote display panel, such as the E2ROIP Remote Operator Interface Panel for remote control and monitoring of the new digital control system and all of the associated devices
  • Optional IEEE Type PSS-2A (Power System Stabilizer) that uses the "Integral of accelerating power" algorithm to provide damping for local mode, inter-area and inter-unit oscillations in the 0.1 to 5.0 hertz range

The new digital static excitation and voltage regulator systems are supplied in NEMA 1 enclosures or can be easily installed as a "shipped-loose" system and mounted directly into the existing excitation system enclosure or generator control panel. This helps to reduce the overall project cost and also allows for a quicker turnaround for the equipment to be available.

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