Voltage sag: It is usually associated with system faults but can also be caused by energization of heavy loads or starting of large motors. Voltage sag is the short reduction in the RMS voltage between 0.1 to 0.9 pu for a duration of 0.5 cycle to 1 minute
In DC microgrid system, Efficiency α 1/Pin For 1 kW loss injecting power is 20 kW For 1.5 kW loss injecting power will be proportional to 30 kW So, Efficiency will be reduced 0.025
Power factor for purely inductive circuit is 0 and power factor angle is 90 degree. Power factor for purely capacitive circuit is 0 and power factor angle is 90 degree Power factor for purely resistive circuit is 1 and power factor angle is 0 degree
The series electromagnet is energized by a coil known as current coil which is connected in series with the load so that it carry the load current. The flux produced by this magnet is proportional to and in phase with the load current.