What SSE Say

Some people have been in touch with SSE and have shared their questions and the responses they received.

Question: Why Not Upgrade Existing Lines?

Dear Lesley

I realise you are bombarded with emails re above but wondered if you had heard back from the technical people re my question ” what are the technical reasons against upgrading the existing pylons to carry 400 kva cables ” , many thanks , <name withheld>


Good Morning … ,

Apologies in the delay responding to your specific question – ” what are the technical reasons against upgrading the existing pylons to carry 400 kva cables ”

A – There are two existing transmission routes between Blackhillock and Kintore.

The original line is built to a 275kV specification and has recently been reconductored with the largest conductors that style of tower can support. This style of tower does not have sufficient space between the cross arms to accommodate the longer insulators and the greater electrical clearance between the live conductor and the earthed cross arm below that is required at 400kV. The extra length of a 400kV insulator string will also cause ground clearance infringements on the bottom conductor.

The second line is built to a 400kV specification and currently operates at 275kV. This line will be reconductored and re-insulated to operate at 400kV, increasing the capacity of the network.

Once that work is complete the network will be operating a full capacity. The Future Energy Scenarios produced by National Grid forecast continuing load growth on the network indicating that further capacity will be required by the mid 2020s. As existing assets will be operating at capacity, new infrastructure will be required to meet the need. SHE-Transmission has a licence responsibility to operate an efficient, economic and coordinated network so we have started planning for this next phase.

I have attached a generic drawing that shows the difference between 275 and 400kV towers.
I hope that helps to clarify the reasons for the new line. If I can be of any further assistance, please don’t hesitate to contact me. Kind regards,

Lesley Dow
Community Liaison Manager
Transmission Land and Communities Team
T: 01738 455115
M: 07876837490
E: lesley.dow@sse.com
Inveralmond House, 200 Dunkeld Road, Perth, PH1 3AQ sse.com ssepd.co.uk

Question: Kemnay House

Ref. Northern Extension of Southern Corridor.
Why has Kemnay House and Policies not been afforded a GDL status exclusion zone as have Castle Fraser, Cluny Castle and Monymusk?
Kemnay House is situated the same distance as Castle Fraser and Cluny Castle from the centre of the corridor and much closer than Monymusk House.


Good Afternoon Mr Noakes,

Many thanks for contacting me regarding the above project.

Kemnay House is a category A listed building and has a number of other listed features surrounding it.  It is located approximately 600m to the north of the preferred route corridor.  Our analysis has assigned a high level of sensitivity to Category A listed buildings and the route selection process will seek to avoid impact on their settings.  Therefore, please be assured that we will fully consider the setting of Kemnay House at the next stage of the route selection process.

Kind regards,