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
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
There is one IEC guideline, number is IEC 599, Statement of guideline is that "If the ratio of carbon dioxide and Carbon monoxide in Dissolve gas analysis test result is more than 11, it is predict that the condition of paper insulation inside the transformer is poor." For healthy condition this ratio will be between 4 to 11.
EXAMIANS