Schweitzer Engineering Laboratories SEL-321 - Figure 1.5: Ground Distance Characteristics; Figure 1.6: Instantaneous, Definite-Time, and Time-Overcurrent Characteristics

1-4 Introduction Date Code 20011026
SEL-321/321-1 Instruction Manual
Figure 1.5: Ground Distance Characteristics
• Four mho zones
• Four quadrilateral zones
• Use quadrilateral, mho,
none, or both
Figure 1.6: Instantaneous, Definite-Time, and Time-
Overcurrent Characteristics
• Four US, four IEC curve
families
• Phase, residual, and
negative-sequence
elements
• Torque-controllable by
distance and directional
elements
• One-cycle or electro-
mechanical reset char-
acteristics
• Four instantaneous/
definite-time elements for
negative-sequence and
for residual overcurrent