(Adds details on the negotiation)
SAO PAULO, Dec 2 (Reuters) - Spain's infrastructure company Ferrovial SA is in talks to acquire from its Spanish rival Grupo Isolux Corsan SA IPO-ISOL.MC three power transmission projects in Brazil, according to a Ferrovial letter seen by Reuters on Friday.
Isolux is undergoing debt restructuring in Spain and has stopped development of the power transmission lines, whose licenses it obtained from the Brazilian government in licensing tenders in 2014 and 2015.
Brazil's electricity watchdog, Aneel, is considering canceling the licenses and promoting a new tender to find a substitute for the battered Spanish company.
Ferrovial sent a letter to Aneel saying it was in talks with Isolux. In the document, it asked the regulator to hold off on the possible cancellation of the licenses. The company said it was evaluating the three projects and that it intended to present an offer to Isolux by Dec. 22 to take responsibility for finishing the transmission lines.
There was no immediate answer from Aneel regarding Ferrovial's request. (Reporting by Luciano Costa; Writing by Marcelo Teixeira; Editing by Lisa Shumaker and Jonathan Oatis)