Power Transfer Distribution Factor is a mathematical value used by grid operators to calculate the impact of a proposed energy transaction on the transmission network. It is expressed as a percentage, showing the fraction of a power transfer that will flow over a specific line or corridor. Dispatchers and market systems use these factors to predict congestion and ensure that scheduling a trade will not overload critical grid infrastructure.
The transaction was cut because the PTDF on the northern intertie showed we would exceed the thermal limit.
High PTDF values mean a transaction heavily impacts a specific line, making it a prime target for curtailment during congestion.
Related terms
Peak shaving
The practice of reducing electrical power consumption during periods of maximum demand on the grid.
Time-of-use rates
A pricing structure where electricity costs vary based on the time of day and season.
Rolling blackout
An intentional, temporary disruption of electrical service to different geographic areas to prevent a grid collapse.