State Grid Corporation is the largest power enterprise in China, formerly known as "State Power Company", including State Grid and all power plants. After the power system reform marked by "separation of power plant and power grid" started in 2000, the power grid business such as transmission and distribution spun off from the former State Power Company was operated by State Grid Corporation, and the power plants were classified into five "power generation groups" (Datang, China Power Investment Corporation, Guodian, Huadian and Huaneng). 20 1 1 according to the "separation of main and auxiliary" scheme of the state-owned assets supervision and administration commission, the auxiliary units such as survey and design, thermal power construction, hydropower construction and maintenance enterprises belonging to provincial (regional) power grid enterprises of State Grid Corporation and China Southern Power Grid Corporation were stripped into organizational systems, and reorganized into two new companies with four central power design and construction enterprises. Today, the auxiliary units of State Grid and China Southern Power Grid in Hebei, Jilin, Shanghai, Fujian, Jiangxi and other 14 provinces and cities, China Water Conservancy and Hydropower Construction Group and China Hydropower Engineering Consulting Group were reorganized into China Electric Power Construction Group Co., Ltd., the auxiliary units of State Grid and China Southern Power Grid in 15 provinces and cities, and China Gezhouba Group and China Electric Power Engineering Consulting Group were reorganized into China Energy Construction Group.