Integrating high-penetration renewable energy is the development trend of future power systems. The comprehensive evaluation of transmission network planning should adapt to the new features of integration of high-penetration renewable energy. This paper introduces the key factors and main procedures of comprehensive evaluation of transmission network planning. An overview of current studies on the evaluation index system and comprehensive evaluation methods is presented. The impacts of integration of high-penetration renewable energy on the comprehensive evaluation of transmission network planning are analyzed in detail including the strong uncertainty resulting from renewable energy

accommodation of renewable energy

mass integration of power electronic devices and AC/DC hybrid power network. On this basis

the future research prospects of comprehensive evaluation of transmission network planning towards integration of high-penetration renewable energy are proposed from the following four aspects: evaluation objects

evaluation index

evaluation method and applications of evaluation results.