What must be synchronized to parallel multiple generating facilities?

What must be synchronized to parallel multiple generating facilities?

• A. The angle of rotation
• B. The physical location
• C. The protection scheme
• D. The color of insulation

Answer: (A)

When connecting multiple generators to share a common load, their outputs must be in step, meaning they run at the same frequency and are in the same phase. The important part here is the phase angle, which is determined by the rotor position and sets the phase of the generator’s output voltage. Before closing the connection to the bus, the generator’s voltage phasor must align with the bus so that the voltages rise and fall together. If the rotor angle isn’t matched, closing the switch can drive large circulating currents, cause voltage fluctuations, and potentially damage equipment or destabilize the system. Physical location doesn’t affect the ability to parallel units—you can connect generators from different sites. The protection scheme matters for safety and fault handling, but it isn’t the parameter you synchronize in order to parallel. The color of insulation has no bearing on electrical synchronization.

When connecting multiple generators to share a common load, their outputs must be in step, meaning they run at the same frequency and are in the same phase. The important part here is the phase angle, which is determined by the rotor position and sets the phase of the generator’s output voltage. Before closing the connection to the bus, the generator’s voltage phasor must align with the bus so that the voltages rise and fall together. If the rotor angle isn’t matched, closing the switch can drive large circulating currents, cause voltage fluctuations, and potentially damage equipment or destabilize the system.

Physical location doesn’t affect the ability to parallel units—you can connect generators from different sites. The protection scheme matters for safety and fault handling, but it isn’t the parameter you synchronize in order to parallel. The color of insulation has no bearing on electrical synchronization.