Grid

The Grid is the physical design of the lines and nodes

Example of a 194 node grid

The grid is modelled as a single line between nodes, therefore if the physical grid has more than one line, this needs to be reflected in the values associated with the line. The physical aspects of the line, Resistance and Reactance are modelled to determine losses. Lines limits can be applied using 'Enforce' so constraints can be modelled.

Grid Details Box (top of the window)

Name and Description	Used to identify and describe the Grid Resource
Base Voltage	Determines the variable losses that occur on a line through the formula: Loss = RZ2 / Base Voltage, where R is the per unit resistance of a line and Z the power flowing through the line in MW.

Grid Lines Box

The Grid Lines Box provides access to details of the Lines connecting Nodes on a Grid. Lines can be added to, or removed from, the Grid Instance and their details edited.

Note: Within EMarket positive line flow (Node from to Node to) is an arbitrary convention. EMarket automatically adjusts for line flow direction at run time.

Line Box Fields

Line Name	Automatically produced from Node From and Node To fields
Node From	The code of the Node defined as the upstream Node when line flow is positive
Node To	The code of the Node defined as the downstream Node when the line flow is positive
Resistance	The per unit resistance of the line
Reactance	The per unit reactance of the line
Winter Limit (MW)	The maximum capacity of the line during the Winter period
Summer Limit (MW)	The maximum capacity of the line during the Summer period
Enforce	When set to Y the Line capacities are enforced during Runs. When set to N, EMarket runs with the Line unconstrained which means that the power flow can exceed the limit values in this table.

Comments

• Nodes need to be present before a line can be entered
• Individual line limits can be modified for defined periods using the schedule
• Individual lines can be entirely 'outaged' through the schedule
• Data can be copied directly from excel cells into cells in EMarket