65/16kV Ackersand - Saas

Submitted by daegerte on Sat, 04/01/2017 - 15:04

The 65 kV Saas valley line connects the S/S Ackersand with the S/SSaas and serves to supply the Saas Valley with electrical energy. The line, which is in operation today, dates from 1958 and has a length of 15.6 km. The route leads from Ackersand up to Saas-Grund and further to the substation. Today, the line consists mainly of wooden poles. On a length of 1.3 km exist small lattice poles, on which a 16kV line is installed in parallel. Some of the old poles were replaced by new concrete poles or tubular steel poles.

Due to the intersection with a aerial cableway, the new line is planned with a underground cable section. Over a length of 1.4 km between S/S Ackersand an transition pole No 1 an underground high voltage plus a medium voltage cable system will be installed. The cable route runs along the large S/S Stalden and the operation building of the Mattmark Kraftwerke.

The project includes the supply, installation and commissioning of 1.4 km long

  • 65 kV cable system with three single-core cables type N2X(FL)2Y 1x400mm2 Cu 60/36 (72.5) kV between S/S Ackersand and the transition pole.
  • 16 kV cable system with one triplex cable type N2X(F)2Y-2Y 1x240mm2 20/12 (24) kV between the P/S Ackerstand and the transition pole.
  • optical fiber cable between the S/S Ackersand (communication rack) and the transition pole.

The cables are installed in cable protection pipes. The 65 kV cable system consists of three sections with two joint bays. In the middle section, three phases of the h.v. cable will be installed in a common duct with a diameter of 200mm.  shafts. The m.v. cable system will interconnect near the second joint bay with the transformer station Räbwier. 

The greatest challenge of this project poses the cable pulling and installation due to the mountainous region, steep slopes and limited space.