# Grid Container¶

The grid container groups all entities that are able to form a full grid model. Two types of grid containers are available:

JointGridContainer
This one is able to hold a grid model spanning several voltage levels. On instantiation, a sub grid topology graph is built. This graph holds SubGridContainers as vertices and transformer models as edges. Thereby, you are able to discover the topology of galvanically separated sub grids and access those sub models directly.

and

SubGridContainer

This one is meant to hold all models, that form a galvanically separated sub grid. In contrast to the JointGridContainer it only covers one voltage level and therefore has an additional field for the predominant voltage level apparent in the container. Why predominant? As of convention, the SubGridContainers hold also reference to the transformers leading to higher sub grids and their higher voltage coupling point.

Let’s shed a more detailed light on the boundaries of a sub grid as of our definition. This especially is important, if the switchgear of the transformer is modeled in detail. We defined, that all nodes in upstream direction of the transformer, that are connected by switches only (therefore are within the switchgear) are counted towards the inferior sub grid structure (here “2”), although they belong to a different voltage level. This decision is taken, because we assume, that the interest to operate on the given switchgear will most likely be placed in the inferior grid structure.

The “real” coupling node A is not comprised in the sub grids node collection, but obviously has reference through the switch between nodes A and B.

A synoptic overview of both classes’ attributes is given here:

## Attributes, Units and Remarks¶

Attribute Unit Remarks
rawGrid see below
systemParticipants see below
graphics see below
subGridTopologyGraph topology of sub grids - only JointGridContainer
predominantVoltageLevel main voltage level - only SubGridContainer
subnet sub grid number - only SubGridContainer

### RawGridElements¶

This sub container simply holds:

### SystemParticipants¶

This sub container simply holds:

and the needed nested thermal models.

### Graphics¶

This sub container simply holds: