(Solved): (b) A switchgear busbar is subjected to voltage variations of +19% and -21% from its nominal value ...

(b) A switchgear busbar is subjected to voltage variations of +19% and -21% from its nominal value lasting for up to 0.40 seconds due to the operation of an automatic welding machine. (i) Argue, whether a device that is compliant with the ITIC curve as shown in Figure Q1(b) tolerate these voltage deviations. (1 mark) (ii) By referring to the ITIC curve as shown in Figure Q1(b), deduce the impact if the duration of the voltage swings lasts for 9 seconds. (1 mark) Note: Any appropriate/short but meaningful answer will get full marks. 250 200 150 - 100 PERCENT CHANGE IN BUS VOLTAGE 0.5 CYCLE, 50 Hz! 50 %0171 RATER -- VOLTAGE 1 -50 -100 0 0.0001 0.001 10 100 1000 0.01 0.11 TIME IN SECONDS Figure Q1 (b)