This paper firstly analyzes the problems of the implementation modes of standard T. On this basis

the serial implementation mode of control performance standard (CPS) and standard T is put forward according to the thought of solving the main contradiction. The power system switches the CPS and standard T to solve the main contradiction in different operating states of ultra-high voltage (UHV) power grid. At the same time

four control modes are designed in consideration of UHV tie-line power deviation and system frequency deviation. Analyses and simulations have been made to prove that there will be no control contradiction between control areas with consideration of UHV tie-line power deviation and system frequency deviation in the serial implementation mode of CPS and standard T. This work is supported by State Grid Corporation of China.