The two companies stated they signed the first part of an agreement that will result in PLC holding a 51% share in Monsson Operation on 15 October.
They expect the integration procedures to continue until the end of November, they added.
Monsson Operation is the operations and maintenance (O&M), and engineering services arm of Romanian company Monsson Group.
This includes the 600MW Fantanele-Cogealac wind farm in south-east Romania, which was co-developed by its parent company.
The company added that PLC would give it "the opportunity to be as independent and involved in strategic decisions as ever" following the acquisition.
It stated that it is "considering strengthening its position in existing markets", and that by joining PLC, it aims to ensure the financing of the projects under construction and of new projects that will be signed in the near future.
Monsson Operation added that becoming part of PLC would give it access to new markets, and it expects to grow in markets such in Germany, Russia and Ukraine.
PLC, meanwhile, has two subsidiaries: PLC System, which offers processing and verification tools for power systems, and PLC Service, which provides operations and maintenance (O&M) in the energy sector.
Michele Scoppio, CEO of the winder PLC group, said: "With this move in the market, we want to create an international company able to deliver a high-quality service to wind turbine manufacturers and renewable energy plant owners."