Given the information, I'll make an educated guess that "Dinh muc 203 QDEVN PDF 2021" might relate to a Vietnamese regulatory document or standard (possibly related to construction, engineering, or technical specifications) issued in 2021.
áp dụng thống nhất cho các cấp điện áp đến 500kV trong Tập đoàn Điện lực Quốc gia Việt Nam. phanmemeta.com dinh muc 203 qdevn pdf 2021
Since this is an internal regulatory document of EVN, it is often shared through professional engineering forums rather than general public government portals. Given the information, I'll make an educated guess
"203/QĐ-EVN" filetype:pdf or "Định mức tổn thất điện năng 203 QĐ-EVN" Given the information