▁consists ▁of ▁one ▁P I ▁controller ▁in ▁order ▁to ▁achieve ▁operation ▁with ▁unity ▁power ▁factor ▁( i . e . ▁Q grid ▁= ▁ 0 ▁). ▁It ▁is ▁obvious ▁that ▁Id N ▁has ▁to ▁be ▁reg ulated ▁to ▁reach ▁zero ▁at ▁steady - state ▁( Id N ref ▁= ▁ 0 ). ▁ ▁We ▁can ▁see ▁the ▁complete ▁system ▁of ▁the ▁grid ▁side ▁converter ▁and ▁the ▁cas c aded ▁P I ▁controller ▁loops ▁in ▁the ▁figure ▁in ▁the ▁right . ▁ ▁Const ruction ▁ ▁As ▁wind ▁tur bine ▁usage ▁has ▁increased , ▁so ▁have ▁companies ▁that ▁assist ▁in ▁the ▁planning ▁and ▁construction ▁of ▁wind ▁tur b ines . ▁Most ▁often , ▁tur bine ▁parts ▁are ▁sh ipped ▁via ▁sea ▁or ▁rail , ▁and ▁then ▁via ▁tr uck ▁to ▁the ▁installation ▁site . ▁Due ▁to ▁the ▁massive ▁size ▁of ▁the ▁components ▁involved , ▁companies ▁usually ▁need ▁to ▁obtain ▁transport ation ▁perm its ▁and ▁ensure ▁that ▁the ▁chosen ▁tr uck ing ▁route ▁is ▁free ▁of ▁potential ▁obst acles ▁such ▁as ▁over pass es , ▁brid ges , ▁and ▁narrow ▁roads . ▁Gr oups ▁known ▁as ▁" re con na issance ▁teams " ▁will ▁sc out ▁the ▁way ▁up ▁to ▁a ▁year ▁in ▁advance ▁as ▁they ▁identify ▁problem atic ▁roads , ▁cut ▁down ▁trees , ▁and ▁re loc ate ▁utility ▁pol es . ▁Tur bine ▁bl ades ▁continue ▁to ▁increase ▁in ▁size , ▁sometimes ▁necess it ating ▁brand ▁new ▁log ist ical ▁plans , ▁as ▁previously - used ▁routes ▁may ▁not ▁allow ▁a ▁larger ▁bla de