{TAIL ~ U0} and P0 are {HEAD ~ a nominal voltage} and nominal active power, respectively, as measured prior to the contingency 
{ TAIL ~ U0 } and P0 are { HEAD ~ a nominal voltage } and nominal active power , respectively , as measured prior to the contingency
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH