PPC, which is 51% owned by the state, is selling a 49% stake in HEDNO.
Assuming an enterprise value, which includes debt, of about 5 billion euros ($5.94 billion) for HEDNO, the minority stake being sold by PPC could be valued at around 2.45 billion euros.
Binding bids were submitted by private equity fund CVC Capital Partners Group and asset managers First Sentier Investors Group, Macquarie Group and KKR Group, PPC said in a bourse filing.
The deadline for the submission of binding offers expired earlier on Friday.
The power utility had shortlisted nine investors for Greece's sole grid, which operates a 242,000 km ($146,978.44) long grid, bringing electricity to about 7 million households and businesses across Greece.
PPC will first make sure that bids fulfil the technical conditions set in the tender before it unseals the financial offers, it said.
PPC is keen to upgrade the grid, which mainly consists of overhead cables susceptible to fails in adverse weather and introduce smart meters to address power thefts.
($1 = 0.8416 euros)
($1 = 1.6465 marka)
(Reporting by Angeliki Koutantou; editing by Michele Kambas, and Louise Heavens)