Transmission-Distribution Interface (TDI)

The physical point(s) at which the upstream Bulk Power System / Transmission System and a downstream Distribution System interconnect, typically at one or several major substations.   

In a conventional, highly bifurcated Power System, these were traditionally known as the Supply-side and Demand-side respectively.     

Power System that host growing volumes of Variable Renewable Energy (VRE) and Consumer Energy Resources (CER/DER) are experiencing growing levels of Volatility which can propagate upstream and downstream in a somewhat ‘tidal’ manner.   

In this more dynamic context, simultaneously ensuring Resource Adequacy, System Security and Reliability will require a much greater level of inter-dependence across the Transmission-Distribution Interface (TDI) than in the past.  

Refer also to Operational Coordination and Transmission-Distribution Interoperability Mechanisms (TDIM) 

Given the fast-evolving nature of power system transformation, the Future Grid Accelerator (FGA) has the status of a perpetual BETA version. Your suggestions for how each concept and definition may be enhanced are very welcome.

All feedback will be reviewed and considered for inclusion in subsequent updates.

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