Creating a Powerflow Case Definition

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>> To create a Powerflow Case Definition:

  1. Place the Data Sources Manager in the Main Window into Powerflow Mode by highlighting the 'Powerflow' data source option
  2. Click the Create button at the foot of the Panel which opens the the Powerflow Case Definition Window
IMPORTANT:  Equation Constraints are allowed in Powerflows, but they do not impact on the power flow in any way at all.

Equation Constraints are allowed in Powerflows so that you can see if their right hand side value is exceeded, and by how much, but they do not impact on the power flows. Power flows are determined only by the generation, demand, line impedances and swing nodes you choose.


Powerflow Case Steps

  1. Naming The Powerflow Case
  2. Selecting the data range for the Powerflow Case
  3. Loading and editing Demand and Generation data
  4. Loading and editing Transmission System data
  5. Selecting the Swing Node/s
  6. Running the Powerflow Case

Naming a Powerflow Case

By default new Powerflow Cases are created with the name: _New_. If a Case of this name already exists a version number in parentheses is appended to the name.

>> To add or change the name of the Powerflow Case:

  1. Click on the Powerflow Name button on the Powerflow Case Definition Window to open the Rename Powerflow Window
  2. Type the new Powerflow Case name and click the OK button

Selecting a Powerflow Case Date Range

Each Powerflow Case must be associated with an Effective Date Range. The Powerflow output will contain data for each Trading Period specified in the Effective Date Range.

NOTE: It is possible to create Powerflow Cases for historical as well as future dates.

>> To specify the Effective Date Range:

  1. Use the Date Selector to specify the date on which the Powerflow Case will start
  2. Use the Trading Period Selector to specify the starting Trading Period for the Powerflow Case
  3. Specify how many Trading Periods (from and include the starting period) you would like the Powerflow Case to cover

NOTES:

  1. EMarketOffer uses the Effective Date Range as a default when loading input data into the Powerflow Case from database or file.
  2. The Powerflow Case works with a single week (seven-days) of input data, Powerflow Cases covering more that 336 periods (seVen-days) will re-cycle Demand and Generation data.


Loading and Editing Demand and Generation Data

>> To load Demand and Generation data in to your Powerflow Case:

  1. Use the Data > Load Data option in the Menu bar of the Powerflow Case Definition Window to open the Load Data Window
  2. Use the Demand and Generation Data Panel to specify the details of the Demand and Generations data you wish to use.

NOTES:

  1. When loading Demand or Generation data from file EMarketOffer uses the date in the file name to establish the day of the week the data will be used for in the profile. Loading two files for a Wednesday means an average of the two days will be made for the weekly profile.
  2. It is possible to load partial files for a limited number of Trading Periods and/or Nodes. Data for the Trading Periods and Nodes in the partial file will overwrite existing data but leave other data in tact.

You can also load Demand and Generation data from previously prepared Demand or Generation Profile files using the Profiles > Demand or Profiles > Generation options in the menu of the Powerflow Case Definition Window.

Finally, you can:

  • Load Demand data into the Definition one Node at a time through the Edit Node Data Grid accessed through the loaded data panel on the Powerflow Case Definition Window. Such loading can be achieved either manually or by cutting and pasting from another application such as Excel.
  • Load Generation data on Units at a time through the Edit Unit Data Grid in the Powerflow Case Definition Window

Editing Loaded Demand and Generation Data

Demand data can be edited individually by Node using the Edit Node Window accessed through the loaded data panel on the Powerflow Case Definition Window (similar functionality can be used to edit loaded Generation data using the Edit Unit Data Grid).

Individual Demand figures can be edited manually or multiple cells can be changed by pasting into a highlighted section of the grid from the clipboard. You can:

  • Replace all of the existing profile by re-loading from the database
  • Use edited demand files to replace all or part of the existing Demand profile.

NOTE: Data pasted into the Demand Grid overwrites existing data as soon as it is pasted.


TIP: You can use the Graph Nodal Demand profile feature (Graph Button on the Edit Node Data Grid) to make a quick visual check on changes you are making to the Nodal Demand profile).

Loading and Editing Transmission System Data

Loading Transmission Data

>> To load Transmission data into your Powerflow Case Definition:

  1. Use the Data > Load Data option in the Menu bar of the Powerflow Case Definition Window to open the Load Data Window
  2. Use the Load Transmission Data Panel to specify the details of the Transmission data you wish to use

Tip: Remember to select a data range for the Transmission System data that fully covers the Powerflow Case Definition Effective Date Range.

Finally you can load Circuit and Equation Constraint data into the Powerflow Case Definition one Circuit and Equation at a time through the Edit Circuits and Edit Equations Information Windows accessed through the loaded data panel on the Powerflow Case Definition Window. This can be achieved either manually or by cutting and pasting from another application such as Excel.

Editing Loaded Circuit Data

Data for individual Circuits can be edited using the Edit Circuit Information Window accessed by double-clicking a circuit in the loaded circuit data panel on the Powerflow Case Definition Window.

Editing Loaded Equation Constraint Data

IMPORTANT:  Equation Constraints are allowed in Powerflows, but they do not impact on the power flow in any way at all.

Equation Constraints are allowed in Powerflows so that you can see if their right hand side value is exceeded, and by how much, but they do not impact on the power flows. Power flows are determined only by the generation, demand, line impedances and swing nodes you choose.


Equation Constraint data can be edited using the Edit Equation Constraint Information Window accessed by double-clicking an equation in the loaded equations data panel on the Powerflow Case Definition Window.

Selecting Swing Nodes

The final step before running the Powerflow Analysis is to select one or more Swing Nodes to be used by the Powerflow model for allocating unmatched Demand.

Swing Nodes are selected through the Swing Node Data Grid in the Powerflow Case Definition Window.

NOTE: it is possible to run a Powerflow Case without specifying a Swing Node, however the Infeasibilities Sub-Panel in the Control Panel of the Main Window will display the following message when viewing the results: "Unable to find Swing Node(s)"

Running a Powerflow Case

>> To run the definition to produce Powerflow outputs:

  1. Click on the Run Powerflow button in the Powerflow Case Definition Window.

Initiating a Run opens the Run Progress Pop-up Window, which shows how many Powerflow Case periods have so far been analysed. You can use the Cancel button to halt the Powerflow Run at any time. Output calculated by the Run up until the time of cancellation can be viewed via the various output viewers.

NOTE: On completion the Main Window is immediately set to Powerflow Data Source mode and shows data from the first period in the Powerflow Case.


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