New Underground Substation at Ilmalantori Completed

A new underground substation, which will meet the growing need for substation capacity, was inaugurated at Ilmalantori. The Pasila region is growing rapidly, and construction will continue in the forthcoming years.

Further construction and the rising number of residents also require increased substation capacity. The substation will also strengthen power distribution in nearby areas, thus improving security of supply.

The construction of the substation started in summer 2013, and it was completed in spring 2015. In order to save valuable urban space, the new substation has been built into an underground cavern at a depth of 30 metres. Helen Ltd’s district cooling storage facility is also located in the same network of tunnels beneath Pasila. The implementation of overground sections at the street level has been visible, e.g. as cabling sites.

At the Ilmalantori substation, waste heat coming from the main transformers is utilised in the heating of the substation premises. The substation uses earth-fault current compensation equipment, which improves the security of supply in the electricity network and minimises power cuts.

Helen Sähköverkko has a total of 23 substations throughout Helsinki. The Ilmalantori substation is the fourth one built underground. The other underground substations are located in Punavuori, Kamppi and Kluuvi. The Meilahti and Vallila substations also utilise underground facilities. The next new substation will be built in Kalasatama, and its construction work will start in spring 2016.

Facts:

• The size of the cavern facility excavated at the Ilmalantori substation: length 132 m x width 15 m x height 13.5 m
• The substation base is 32 metres below Ilmalankatu
• The total length of the substation is as long as 70 metres
• A total of some 33 kilometres of cabling was laid in the construction stage
• The construction of the substation started in 2013, and the new station will be inaugurated in September 2015
• Helen Sähköverkko has a total of 23 substations in Helsinki.

Source & photo: Helen