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By Luciano Costa
SAO PAULO, April 24 (Reuters) - Brazil's power sector regulator Aneel sold 31 of 35 available licenses at an auction on Monday to build and operate power transmission lines in Latin America's largest economy.
The projects are expected to require 12.7 billion reais ($4.1 billion) of investments, Aneel officials said.
If all 35 licenses had been sold, the projects were expected to draw a total of 13.1 billion reais in investments and add 7,400 kilometers of power lines to Brazil's grid in 20 states.
The sale was a highly competitive process after the Brazilian government increased the rate of return on power transmission investments last year.
In four cases, investors made bids representing a more than 50 percent discount on the maximum allowed annual revenue under the rules of the licenses, which are valid for 30 years.
Analysts had expected bids for nearly all 35 licenses. ($1 = 3.13 Brazilian reais) (Reporting by Luciano Costa; Writing by Ana Mano; Editing by Chizu Nomiyama and James Dalgleish)