VCB ISM: Specifications

TECHNICAL DATA

Type of ISM	ISM15_LD	ISM15_Shell	ISM15_MD	ISM15_HD	ISM25_LD	ISM25_Shell
Rated voltage (Ur)	≤ 17.5 kV	≤ 17.5 kV	≤ 17.5 kV	≤ 17.5 kV	≤ 24 kV	≤ 24 kV
Rated normal current (Ir)	≤ 1250 A	≤ 2000 A	≤ 1250 A	≤ 3150 A	≤ 1250 A	≤ 2000 A
Rated power frequency withstand voltage (Ud)	42 kV	42 kV	42 kV	42 kV	50 kV	50 kV
Rated lightning impulse withstand voltage (Up)	95 kV	95 kV	95 kV	95 kV	125 kV	125 kV
Rated short-circuit breaking current (Isc)	≤ 20 kA	≤ 31.5 kA	≤ 31.5 kA	≤ 31.5 kA	≤ 20 kA	≤ 25 kA
Rated short-time withstand current (Ik)	≤ 52 kA	≤ 82 kA	≤ 82 kA	≤ 82 kA	≤ 52 kA	≤ 64 kA
Rated short-time withstand current (Ik)	≤ 20 kA	≤ 31.5 kA	≤ 31.5 kA	≤ 31.5 kA	≤ 20 kA	≤ 25 kA
Rated duration of short circuit (tk)	4 s
Rated frequency (fr)	50/60 Hz
Mechanical life (CO)	50,000	30,000	30,000	30,000	30,000	30,000
Rated breaking current operating sequence	O-0.3s-CO-15s-CO