Security assessment method for power grid planning under high penetration of variable generation

The affiliation of stability and security is discussed. It is point out that the static security restrains, transient stability restrains and whole process security assessment should be deal with under different procedures in power grid planning. The procedure of security assessment for power grid planning under high penetration of variable generation is presented. It is point out that a part of the courses of the cascading events is with the features of the open complex giant system and that part should be simplified for it can´t be simulated exactly. Another part of the courses is with strong cause and effect relationship between the front and back events and it can be simulated by improved simulation softwares. The overall process risk assessment method taking into account the pre-fault states of the generation system is presented. By the method, the costs of stabilizing facilities and the power cut losses will be counted in the composite annual costs for comparing and choosing the planning schemes.