Value of Sequential-Time Simulations in Distribution Planning

Distribution planning has been generally focused on providing sufficient base power delivery capacity to supply the peak load demand. Renewable generation and various smart grid technologies add the requirement that the time-varying characteristic of controls and loads be included in the planning problem. A sequential-time power flow solution capability is needed to properly account for the time-dependent impact of these technologies and any other technology that results in significant changes to the daily loadshape. Having the capability to perform chronological simulations allows the distribution planner to properly account for the effects of such things as shunt capacitor switching controls, modifying voltage regulation schemes to provide headroom for distributed generation and to optimize voltage profiles, and modeling advanced inverter controls. This paper will discuss some recent research of the Electric Power Research Institute in this area. Examples will demonstrate the value of sequential-time simulations.