Rosalind Craven, who lives near Huby, confronted representatives from the company when they arrived at Holme Farm on Tuesday at 0935 BST.
Mrs Craven, along with 12 supporters, met the National Grid contractors and barred the gates of her farm to them.
After a 15 minute confrontation, the six company representatives left the farm.
The farmer has spent the last 11 years fighting plans to construct three pylons on her land and says she will not give up.
David Mercer, the project manager from National Grid, said the company regretted having to proceed in the way they did.
"We were trying to commence construction on Mrs Craven's land but unfortunately were not able to do so.
"Our lawyers will now look at the situation and advise me whether we should apply to the courts for an injunction."
Earlier Mrs Craven said she did not know what to expect.
"I'm feeling rather anxious as you might imagine after waiting 11 years," she said.
"It's very difficult to know what to expect when the National Grid says they're going to arrive at your gate.
"After 11 years, I see absolutely no reason why I should give in at the moment so I shall carry on as long as I can.
"It would very regrettable if they do try to gain access by force because I have written a letter refusing them permission and that should be sufficient for the occasion."