220-kV and above class transmission and substation facilities In 2005 there were 325 supply enterprises (including 29 EHV transmission and substation enterprises) and 221 generation enterprises all over the country. Main reliability indexes of 13 kinds of transmission and substation facilities in 2004 and 2005 are shown in Table 1. It can been seen that the reliability indexes in 2005 remained at a high Jevel, and their availability factor came up to over 98%. This embodied that the enterprises were still able to put the reliability management work in the 220-kV and above class transmission and substation facilities In 2005 there were 325 supply enterprises (including 29 EHV transmission and substation enterprises) and 221 generation enterprises all over the country. Main reliability indexes of 13 kinds of transmission and substation facilities in 2004 and 2005 are shown in Table 1. It can been seen that the reliability indexes in 2005 remained at a high Jevel, and their availability factor came up to over 98%. This embodied that the enterprises were still able to put the reliability management work in the