I think you don't have experiences about construction works of such projects. EVN is project owner, but PMU (project management Unit) it is directly responsible for management of construction works, installing M&I equipment's and making acceptance hereof, hand over project to operating management board when it completed, based on procedures what defined by related Law and regulations in Vietnam.
For example, earth work, concrete works or M&I works, step by step... which have to going over inspection procedures made by third party. It called as "Supervision consultant". Such consultant shall be independent from Design Consultant and Project owner (or PMU), to prevent any mishandling of contractors to the qualities of the project (mẹ hát, con khen hay).
In this project, supervision consultant can be Russia, Korea, Japan, France Company or others international company from developed countries following terms and conditions of Loan Agreement ( the choice should be following bidding process or direct nomination approval by Ministry of Plan and Investment - Government). Any case, the international Supervision Company should be use local consultant base on contract (should be engaged to provide personal staff only) to do some works on project site (earth works or concrete works etc), we have enough measurement instruments to do that.
I'm awaiting, hopefully no lose, bro.