Type B MCB: Type B devices are generally suitable for domestic applications. They are designed to trip at fault currents of 3 - 5 times rated current.
Type C MCB: Type C devices are the normal choice for commercial and industrial applications These devices are designed to trip at 5 - 10 times rated current
Type D MCB: The Type D devices have more limited applications, normally in industrial use where high inrush currents may be expected. Type D devices are designed to trip at 10 - 20 times.
Bus Type - Known Parameter - Unknown Parameter Load Bus -P, Q - V, phase angle Generator Bus - P, V (magnitude) - Q, Voltage phase angle Slack Bus Voltage - magnitude and phase angle - P, Q
Here auto transformer change voltage from 600 V to 200 V. Voltage ratio (a) = 600/200 = 3 kVA rating of the auto-transformer = (a/(a - 1))*(kVA rating of auto transformer) = (3/2)*20 = 30 kVA
EXAMIANS