Logical Data Structure

EMarketOffer uses two broad types of data:

Static Data: Static data describes the Items Modelled in EMarketOffer (e.g. Generator maximum capacity).

Dynamic Data: Dynamic data described the state of the Modelled Items defined by the static data and changes rapidly over time, typically by Trading Period (e.g. Nodal Price)

Terminology

EMarketOffer's data design consists of 'things' included in the model, and the characteristics of those 'things'. In this manual the 'things' are called Entities and their characteristics are called Traits. Traits may be static or dynamic.

For example the Circuit Entity can have the static Traits of Start Node and End Node, and the dynamic Traits of Powerflow and Loss by Trading Period.

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NOTE: : Static data is not permanently fixed and may, at times, be quite changeable, but within the context of EMarketOffer it is not necessary to be able to track such changes down to the Trading Period level.

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Modelled Items

Four broad categories of item (Entity) are modelled in EMarketOffer:

Item Type	Relate To
System	The physical Transmission System
Market	The routine operation of the wholesale Market (Offers, Load, Price)
Commercial	Generation Companies and their retail and hedging operations
Geographical	Physical points and regional positioning

System Items

The following table lists and describes the System items modelled in EMarketOffer.

Item (Entity)	Description	Attribute (Trait)
System Node	Any point in the NZ Transmission System to which a Circuit can be connected	Name
Substation	One or more System and/or Market Nodes located at a single geographical location	Name Component Node
Circuit	A branch (Circuit) conducting power on the NZ Transmission System	Name From Node To Node Contributes to HVDC (Yes/No) Resistance Reactance Capacity (Summer/Winter)