Status

Context

There are certain transmission lines that can have different ratings depending on their configuration. A commonly cited example is underwater lines with cables packed tightly in trays, where certain combinations of the conductors may be turned on and off. Switching conductors on and off obviously changes the amount of copper that can carry electrons. However, to add additional complexity, the wires are close enough together that they can heat each other up as well, and the overall rating must take this into account. Therefore, each possible combination will have a unique rating.

When computing AARs however, it is necessary to take the configuration into account so that the AAR accounts for the actual or forecasted configuration of the line. Therefore, no special accommodation needs to be considered for AAR exchange in TROLIE.

However, for seasonal ratings, the configuration of the line cannot be forecasted accurately for use as a recourse rating. A separate rating must be provided for each configuration, so that the right rating may be used based on the configuration of the line.

This decision records a strategy for these “conditional” ratings in TROLIE.

Decision

TROLIE will contain no specific schema elements to represent conditional ratings. For lines that require conditional ratings, TROLIE servers must expose unique resource identifiers representing each condition / permutation of the configuration.

This follows from the similar precedent set by the decision for directional ratings.

Conditional-Resource Naming

Much like the problem in naming directional ratings, there is currently no consistent approach as to how these “conditions” are represented. TROLIE implementations will be left on their own to implement a convention for these names, likely concatenating the facility ID with an ID for each possible condition.

Consequences

An example is provided in the seasonal ratings examples.