Flow-based Constraints

Returns a list of flow-based constraints per market, date and one domain

Flow-based capacity constraints represent limits on critical network elements in the power grid. Flow-based constraints are used in combination with ATC capacities to calculate flows inside of flow-based regions.

Flow-based capacity constraints are given per delivery period. Each period contains multiple constraints, and each constraint consists of:

• RAM (Remaining Available Margin) - the available margin for the critical network element, which serves as an upper bound on the total consumption of this element by different bidding areas.
• A list of PTDFs (Power Transfer Distribution Factors) for each Bidding Zone in the corresponding Flow-Based region. A PTDF indicates how much a bidding zone's Net-Position contributes to the load of the critical network element (limited by RAM).

To see if a constraint is binding (or how close it is to being reached), multiply the Net-Position (NP) for each Bidding Zone by its respective PTDF. Then, sum the results of each multiplication. This must result in a value that is lower or equal to the RAM.

When the sum equals the RAM, the corresponding constraint (CNEC) is binding. This can be exemplified by the following formula:

PTDF1 * NP1 + PTDF2 * NP2 + ... + PTDFn * NPn ≤ RAM

Euphemia ensures that these constraints will always be respected.

The Net-Position of a Bidding Zone is defined as Total Export - Total Import for a Bidding Zone. In our data model, this is easiest gotten from the Flow model, and refers to -(totalNetPosition) for each delivery period and area.

Response field descriptions

periods: a list of delivery periods. Each period has

• deliveryStart: the start time of the delivery period
• deliveryEnd: the end time of the delivery period
• constraints: a list of constraints.

Each constraint consist of:

• id: an identifier for the unit. Note that this id is only to identify the constraint within this market coupling session
• name: an optional name for the unit, not always present
• remainingAvailableMargin: the RAM value, described above
• powerTransferDistributionFactors: a list of Power Transfer Distribution factors for each area, described above