▁Academy ▁( S DE P RA , ▁ 山 东 电 力 研 究 院 ) ▁of ▁Sh and ong ▁Electric ▁Power ▁Co ., ▁Ltd . ▁( S DE P , ▁ 国 网 山 东 省 电 力 公 司 ), ▁a ▁wh olly ▁owned ▁subs idi ary ▁of ▁S G CC , ▁for ▁aer ial ▁ins pection ▁of ▁overhead ▁power line ▁ins pection . ▁Z D - II ▁is ▁an ▁un mann ed ▁hel ic opter ▁in ▁conventional ▁hel ic opter ▁layout . ▁ ▁Z N - 1 ▁Z N - 1 ▁is ▁an ▁U AV ▁developed ▁by ▁S DE P RA ▁of ▁S DE P ▁of ▁S G CC ▁for ▁aer ial ▁ins pection ▁of ▁overhead ▁power line ▁ins pection . ▁Z N - 1 ▁is ▁an ▁un mann ed ▁hel ic opter ▁in ▁conventional ▁hel ic opter ▁layout , ▁and ▁it ▁is ▁the ▁first ▁U AV ▁developed ▁by ▁S DE P RA , ▁with ▁program ▁first ▁begun ▁in ▁ 2 0 0 9 ▁with ▁a ▁team ▁of ▁eleven ▁members . ▁ ▁Z N - 2 ▁Z N - 2 ▁is ▁a ▁development ▁of ▁earlier ▁Z N - 1 ▁and ▁is ▁currently ▁in ▁service . ▁Like ▁its ▁prede cess or ▁Z N - 1 , ▁it ▁is ▁also ▁intended ▁for ▁aer ial ▁ins pection ▁of ▁overhead ▁power ▁lines ▁and ▁it ▁is ▁developed ▁by ▁the ▁same ▁development ▁team ▁of ▁Z N - 1 . ▁Z N - 2 ▁is ▁also ▁an ▁un mann ed ▁hel ic opter ▁and ▁when ▁performing ▁the