Issue 87

Formal title: Busbar voltage transformer metering for Offshore wind farms under OFTO arrangements

Current Status


The size and weight of VTs used in Metering Systems of Offshore wind farms can add significant weight and space requirements to a project. This in turn can make developing new wind farms more complex and costly, which ultimately will have a negative effect for end consumers who will have to fund this through their energy bills. The proposer believes that there are effective alternatives to this metering set up, which can reduce the number of VTs (and hence weight) required, without impacting on the quality of data used in Settlement.


Siemens Transmission and Distribution Limited raised Issue 87 on 3 March 2020. The first Issue group meeting took place on 6 July, where the group considered potential solutions to the Issue. The group considered whether the solution may be extended to cover onshore sites, and requested some clarifications for consideration at the next meeting.

The 2nd meeting of the Issue 87 Group took place on 22 September, where the Proposer and group considered outcomes of the actions and agreed to extend the scope of the solution to cover onshore arrangements. Issue 87 struggled to attract a large group, but the group believe that the extended solution may attract further interest and have directed Elexon to prepare a ‘one pager’ and disseminate this via its communication channels.

Next Events

The Issue 87 group has identified a solution that reduces the need for multiple voltage
transformers (VTs), at the feeder/string level on Offshore wind farm platforms, by allowing
the placement of VTs at the busbar. In order to take forward the findings of Issue 87, the group recommend that a Change
Proposal be progressed. The BSC Panel considered the Issue 87 Report at its meeting in July 2021 and made no further comment.


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