Others here can probably refine the details - but generally transmission (typically 132 to 400 kV) is handled by the National Grid and distribution (230V to 66kV) handled by local Distribution Network Operators (DNOs) of which there are quite a few, loosely based on the old regional electricity boards. (Just to confuse matters, one DNO, until recently called Western Power Distribution now goes by the name National Grid as well). There are also independent companies that do some DNO type work (IDNOs). What their arrangements for design are I don't know, I'd guess they mostly do things in house, but that's only a guess).

   - Andy. 

From where I stand, DNOs and the ICPs / contractors working on their behalf seem to have relatively few full-time protection engineers who will have considerable authority with a fairly long tenure, but with settings on a given project being determined from company standards and policies and for more complex or higher voltage plant by studies commissioned from external consultants specialising in such.

In my industry at least asset owners won’t have protection engineers, and even many Technical Advisors / Owner’s Engineers won’t have a full time protection engineer on the books; they too would rely on studies by third parties (which is not to say they wouldn’t employ someone who understands protection! But it would be a more general-purpose ) Other industries no doubt vary with the complexity of the plant and nature of the hazards.

Some (ie, the bigger) ICPs and HV contractors will have the capability in-house but most of those I’ve worked with are SMEs who don’t have the volume of projects and you might be best placed looking at the consultancies serving them.

I do know that there are also several agencies that appear to provide DNOs with engineers on a contract basis; I don't know if that would extend to a protection specialist.

Note that the above applies to distribution networks ie 6-132kV and private connections thereto. I don’t know what National Grid do for protection on the transmission network.

Hope that helps; there may be others with a different perspective.

Thanks all

This sounds a lot like the structure here in NZ.  The companies operating at distribution level (we call them Electricity Supply Companies, ESCs) don't often employ dedicated protection engineers, the larger ESCs may have a few, but most ESCs use generalist power system engineers who have some protection knowledge as a part of their skill set.  The more complex projects requiring specialist protection knowledge get outsourced to consultancies.  Several ESCs have an affiliated contracting arm  which bids for construction and maintenance work on their network and on other networks, this sounds similar to your ICPs.

Our national grid (mainly 220 and 110 with small amounts of other voltages) has a larger group of protection engineers, but also outsources a lot of its protection design due to the sheer volume of work involved.

I'd be obliged if anyone here can name some of the consultancies that provide protection services (like the ones Jam described) and are based in the south of England.

- Bevan