BEIJING - The State Grid Corporation of China, the country's biggest utility, said on Wednesday that it has completed purchase of a 24-percent stake in Greece's power grid operator, ADMIE.

The 320-million-euro deal marks another major investment by the State Grid in Europe after buying stakes of power grid companies in Portugal and Italy.

ADMIE is owned by Greece's Public Power Corporation (PPC), which owns, runs and maintains the power transmission network across Greece. The network, which is integrated with grids in many other European countries, is a key power transmission corridor in southern Europe.

Beating bidders from Italy and France, the State Grid won the tender in October 2016. Upon completion of the stake transfer, the State Grid will send its own management team to the Greek company.

The two companies will also strengthen cooperation in power grid construction, financial investment, grid operation, research and development and personnel training.

State Grid owns stakes of backbone power grids in seven countries and regions including Italy, Portugal and Australia. It manages assets valued at more than $56.8 billion. All of its overseas projects are profitable.