Emergency services were called to the Blackhillock substation site in Keith at around 8.50am on Friday 28 October.
Police and the Health & Safety Executive are investigating the circumstances of the death.
BAM Nuttall is working with Siemens on the infrastructure of the substation for SSE, which is being expanded to allow renewable energy sources to connect to the grid.
A statement from the contractor said the worker died "following injuries sustained in an incident at the Blackhillock substation".
Stephen Fox, chief executive of BAM Nuttall, said: "Our thoughts and deepest condolences go out to all of the family, friends and colleagues of our employee, who was involved in this tragic incident.
"We are working closely with all relevant agencies and authorities and a full investigation is under way."
Colin Nicol, managing director of Scottish & Southern Electricity Networks, said: "I would like to express our sincere condolences to the family and all those affected by today's tragic incident.
"We are offering our full support to Siemens BAM as they liaise with the relevant authorities and commence the investigation."