The following is an example of our Normal Mode and Emergency Mode Sequence of Operation details.

Normal Mode

  1. All Generator Breakers 52-G1 through 52-G(X) are Open and All Generators G1 through G(X) are offline and available
  2. Generator Transfer Breaker 52-GB1 is open
  3. Utility Breaker 52-UB1 is closed and serving the load
  4. All Feeder Breakers 52-F1 through 52-F(X) are closed
  5. Metering devices poling the loads register voltages greater than 75% of the rated 4160V.

Emergency Mode

  1. Utility Undervoltage relay contact pickups (closes) and sends a signal to the generator and switchgear controls that a power outage has occured and the system enters emergency mode.
  2. Utility Breaker 52-UB1 opens and all Non-essential Loads are disconnected from the bus by opening Feeder Breakers 52-F1, 52-F2 and 52-F3
  3. All available generators scramble start with the first generator upto rated frequency and voltage closing to the dead emergency bus.
  4. Generator Transfer Breaker 52-GB1 closes and the first online generator is powering the essential loads only through Feeder Breaker 52-F4
  5. Metering devices pole the total amount of Active Power (Kilowatts) through the online Generator. 
  6. Additional Load shall be brought online based on number of generators online and thenameplate rating of each generator.
  7. An active "Load Management/Load Shed" system shall not allow the total load to increase to greater than all online generators subtracted by the nameplate rating of the largest generator online to ensure complete N+1 redundancy if a generator fails while online
  8. Subsequent Generators parallel to the online generator by matching phase and voltage. Once a generator is within the specified frequency phase window (typically set to 8% phase window difference) and voltage matching (typically set to 5V on secondary (120V secondary)) for a pre-defined time, the generator breaker 52-G(X) will close and the generator will be "online". All phase window, voltage matching and time delays shall be set by the manufacturer and based upon industry standards.
    1. A generator is an AC Voltage sinusoidal source with a Magnitude (Voltage) and Wave/Period (Frequency).
    2. The generator is seen as "in-phase" when the respective synchroscope of the generator attempting to close its breaker reaches the 12-oclock position. The syncroscope does not consider voltage matching which is typically much easier to achieve. The 12-oclock position represents a complete overlap of the AC sinusoidal waves of the respective sources.
  9. All remaining generators shall parallel to the live bus as specified above.
  10. The Power Plant is now running completely on generator.