Composite Buses Column (optional)
Column Type = Boolean
This optional column is used to specify composite buses for bulk area transfers. This column can be set as follows:
TRUE - to model external aggregate areas as having a composite generator bus and composite demand bus using information from the zonal model. This column only has an effect for external areas (not set to "OPF" in the Solution Method column).
FALSE - the composite generators and demand buses are disconnected from the aggregate area.
NULL - a blank cell defaults to TRUE.
If this column is not in the table then it is assumed that composite buses are turned on (set to TRUE) for all external areas.
It is recommended that aggregate areas adjacent to areas on OPF be set to TRUE.
In the Shift Factor and Angles method external areas that are run on composite bus are handled by equivalently reducing the external areas injection onto the boundary buses between OPF areas and the external areas. The equivalent reduction preserves the electrical dispatch assuming transmission lines in the external areas are not monitored. Furthermore, all segments in an external area are preserved.
Please see Nodal Angles Solution Method for further details on the equivalent reduction of external areas on Composite Bus.
Interfaces between two external aggregate areas (with composite buses) are recognized and are part of the nodal network. This includes external aggregate areas that do not connect directly to an area on OPF.
This optional column is used to specify how interactions with external areas should be handled. It only has an effect for external areas, i.e. those not set to OPF in the Solution Method column. This column can be set as follows:
TRUE – the external aggregate area's demand and generation is modeled in the solution using an automatic mapping from the original external demand and generation buses to the boundary buses being modeled. The network reduction of the external area’s injection buses onto the boundary buses preserves the electrical dispatch assuming transmission lines in the external areas are not monitored.
Furthermore, the generator details of all resources in the external generators are preserved, with the possible exception of the unmapped generators depending on the value in the Composite Bus Resources column. See the Nodal Composite Bus Modeling article for more detail on how the network reduction is done. TRUE is the default value when not specified.
FALSE - the composite generators and demand are not represented at all in the system being solved.
- NULL - a blank cell defaults to TRUE.
It is generally recommended that external aggregate areas adjacent to aggregate areas on OPF be set to TRUE.
Composite Buses Column