Injection Group Overview

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An injection group is a collection of loads, generators, switched shunts, buses, and/or other injection groups. In that respect, injection groups are somewhat analogous to areas and zones. However, unlike with areas and zones, generators, loads, switched shunts, buses, and injection groups can belong to more than one injection group. Moreover, a single injection group may contain generators, loads, switched shunts, and buses from several different areas and zones. Thus, injection groups are useful when modeling a collection of generators, loads, switched shunts, and buses that act together as a unit, regardless of each individual’s area or zone affiliation. The most common use for injection groups is to model a transfer of power from one group of generators and loads to another for PTDF calculations and for PV/QV analysis. They are called injection groups because their components (generators, loads, and switched shunts) are objects that inject power into the network.

 

Buses as Injection Points

An injection point within an injection group can simply be defined as a bus. Bus injection points will be ignored in tools that use injection groups and actually cause changes to the system, i.e. scaling and ramping a power transfer in the PV or ATC tools. Without defining specific devices for the injection, Simulator makes no assumption as to how generators or loads should be adjusted at a bus. Standalone sensitivities tools that by the nature of their linear calculations do not require injection from specific devices can use bus injection points.

Specifically, tools that do NOT allow the use of bus injection points and for which bus injection points will be ignored are the following. All other tools that allow the use of injection groups or involve the use of injection group participation points to determine some sort of weighting will include bus participation points: