% Calculates half hourly injection into the 'grid' at each 'grid exit point' (any injection onto the grid 
% resulting from embedded generation exceeding local load behind a GXP)

calculate GXPImport.NorthIsthmus =  pos(zpad(NI.Kaikohe.Import)) + pos(zpad(NI.Silverdale.Import))
calculate GXPImport.Auckland = pos(zpad(NI.Bombay.110KV.Import))
calculate GXPImport.Waikato = pos(zpad(NI.Hamilton.NZR.P1P2Nett.Active.Import))+ pos(zpad(NI.Lichfield.T1.Import)) + pos(zpad(NI.Lichfield.T2.Import)) + pos(zpad(NI.TeKowhai.Import)) + pos(zpad(NI.Wairakei.Import))
calculate GXPImport.BayOfPlenty = pos(zpad(NI.Kawerau.Town.Import)) + pos(zpad(NI.Kawerau.Tasman.2.Import)) + pos(zpad(NI.Rotorua.11KV.Import)) +  pos(zpad(NI.Tauranga.33KV.Import)) + pos(zpad(NI.Matahina.Import))
calculate GXPImport.Central = pos(zpad(NI.Bunnythorpe.Import)) + pos(zpad(NI.Linton.Import))+ pos(zpad(NI.Ongarue.Import))+ pos(zpad(NI.Tangiwai.NZR.P1P2Nett.Active.Import)) + pos(zpad(NI.Tokaanu.Import))
calculate GXPImport.HawkesBay = pos(zpad(NI.Wairoa.11KV.Import))
calculate GXPImport.Taranaki = pos(zpad(NI.Hawera.33KV.Import)) + pos(zpad(NI.Taumarunui.NZR.P1P2Nett.Active.Import)) + pos(zpad(NI.Huirangi.Import))
calculate GXPImport.Wellington = pos(zpad(NI.Greytown.33KV.Import))
calculate GXPImport.NelsonMarlborough = zero
calculate GXPImport.WestCoast = pos(zpad(SI.Arahura.Import)) + pos(zpad(SI.Westport.Orowaiti.Code1.Import)) + pos(zpad(SI.Westport.Orowaiti.Code2.Import)) + pos(zpad(SI.Westport.Robertson.Import)) + pos(zpad(SI.Dobson.33KV.Import)) + pos(zpad(SI.Greymouth.Import)) + pos(zpad(SI.Kumara.Import))
calculate GXPImport.Canterbury = pos(zpad(SI.Kimberley.66KV.1.Import)) + pos(zpad(SI.Kimberley.66KV.2.Import)) + pos(zpad(SI.Ashburton.66KV.Import)) + pos(zpad( SI.Springston.66KV.Import))
calculate GXPImport.SouthCanterbury = pos(zpad(SI.Albury.Import))
calculate GXPImport.OtagoSouthland = pos(zpad(SI.NorthMakarewa.Import)) + pos(zpad(SI.Clyde.Import)) + pos(zpad(SI.Cromwell.Import)) + pos(zpad(SI.Naseby.Import)) + pos(zpad(SI.Winton.66KV.Import)) + pos(zpad(SI.Dunedin.HalfwayBush.Import.1)) + pos(zpad(SI.Dunedin.HalfwayBush.Import.2)) + pos(zpad(SI.Studholme.Import))
calculate GXPImport.NorthIsland = GXPImport.NorthIsthmus + GXPImport.Auckland + GXPImport.Waikato + GXPImport.BayOfPlenty + GXPImport.Central + GXPImport.HawkesBay + GXPImport.Taranaki + GXPImport.Wellington
calculate GXPImport.SouthIsland = GXPImport.NelsonMarlborough + GXPImport.WestCoast + GXPImport.Canterbury + GXPImport.SouthCanterbury + GXPImport.OtagoSouthland
calculate GXPImport.NewZealand = GXPImport.NorthIsland + GXPImport.SouthIsland