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Boundary node – marks ownership system boundaries and transfers 100% of flow from upstream to the downstream owners. Orders may or may not be allowed to pass upstream through the boundary, the modeller determines whether this occurs for each downstream owner. Where a downstream owner’s orders are to ‘cross the boundary’, 100% of the total order must be passed upstream. The modeller will determine the percentage of the downstream owner’s total order to transfer to each upstream owner. Note that an upstream owner may receive orders from multiple downstream owners; or
In-system node – allows you to specify a transfer of flow ownership between owners within the same ownership system at a particular location, to reflect regulatory requirements that could operate under certain conditions. For example, an owner may receive additional flow over summer, or when there is flow above a given threshold. As regulatory requirements vary between jurisdictions and may change over time, you can define functions to represent the conditions of flow transfer.
Note that when configured as an in-system node, it is possible that only some owners transfer flow, and likely that only some of their flow is transferred. It is possible that the required transfer exceeds an owner’s share of the total flow. When this occurs, the transfer must be limited to the owner’s flow volume.
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Whether a Transfer Ownership Node is configured as a boundary or in-system node is determined in the Ownership Setup dialog (Edit » Ownership). Select Boundaries and choose which ownership system the Transfer Ownership node will be associated with, see Boundaries for more information. If the Transfer Ownership node is on the border between two ownership systems it will be a boundary node, otherwise it will be an in-system node. This configuration can be confirmed in the Transfer Ownership node feature editor. If the Upstream Ownership System and Downstream Ownership System are the same system, it is an in-system node (Figure 1), otherwise it is a boundary node.
You can use the Transfer Ownership node’s feature editor to specify the orders made by owners, which travel from the bottom to the top of the network. You can also define how the flow will be distributed among owners in different ownership systems. It travels from the top to the bottom of the network, and is hence, conceptually the opposite of orders.
Orders
This tab allows you to transfer the ownership of orders as they propagate upstream. It dictates how orders will be transferred between upstream and downstream owners for a given downstream ownership system. For the example shown in Figure 1, the Downstream owner NSW will transfer 100% of its orders to Upstream owner NSW, Downstream owner VIC will transfer equal amounts of its orders between Upstream owners NSW and VIC, and Downstream owner QLD will transfer equal amounts of orders to all the Upstream owners (NSW, VIC and QLD).
Figure 1. Transfer Ownership node, Ordering
Flow
Just as with ordering, the Flow tab (Figure 2) allows you to transfer ownership of flow as it travels down the network for a given downstream ownership system. Figure 2 shows a transfer ownership node that has been configured as an in-system node. Owner allocation are specified using a function. Click Function... to open the Function Editor. Examples of functions you could use to specify allocations are shown in Table 1.
Table 1. Example allocations among owners
| Upstream owners | NSW | VIC | QLD |
|---|---|---|---|
| NSW | $NSWOutflow*0.8 | $NSWOutflow*0.2 | |
| VIC | if($now.year=2013,$VICOutflow,0) | 0 | |
| QLD | 0.5*Max(0,($QLDOutflow-$threshold)) | 0.5*Max(0,($QLDOutflow-$threshold)) |
The functions defined in Table 1 are interpreted as follows:
- NSW will always transfers 80% of their outflow to VIC, and 20% to QLD at this node;
- VIC will transfer all its outflow to NSW for the year 2013 (none for QLD);
- When QLD has flow above a threshold, 50% of its outflow will be transferred to NSW and the other 50% to VIC.