This defines the dielectric withstand of equipment to power frequency over voltages and lightning impulses.
Ud: Over voltages of internal origin, accompany all changes in the circuit: opening or closing a circuit, breakdown or shorting across an insulator, etc… It is simulated in a laboratory by the rated power-frequency withstand voltage for one minute.
Up: Over voltages of external origin or atmospheric origin occur when lightning falls on or near a line. The voltage wave that results is simulated in a laboratory and is called the rated lightning impulse withstand voltage.
N.B.: IEC 62271-1, article 4 sets the various voltage values together with, in article 6, the dielectric testing conditions.
Ud: Over voltages of internal origin, accompany all changes in the circuit: opening or closing a circuit, breakdown or shorting across an insulator, etc… It is simulated in a laboratory by the rated power-frequency withstand voltage for one minute.
Up: Over voltages of external origin or atmospheric origin occur when lightning falls on or near a line. The voltage wave that results is simulated in a laboratory and is called the rated lightning impulse withstand voltage.
N.B.: IEC 62271-1, article 4 sets the various voltage values together with, in article 6, the dielectric testing conditions.
Released for: Schneider Electric India
