Line Loading Replicator

 

The Line Loading Replicator will attempt to set the loading on a transmission line or interface to a desired real power flow amount. This is accomplished by calculating distribution factors for a selected group of loads and generators to determine how the real power injection of these elements can be adjusted to produce the desired flow. If the desired flow cannot be met, the new flow amount that can be achieved and the injection changes required to meet this flow will be reported. Minimum and maximum MW limits for loads and generators will be enforced when calculating the injection changes.

To open the Line Loading Replicator, go to the Tools ribbon tab, and choose Line Loading Replicator from the Run Mode ribbon group. This is only available in Run Mode.

 

Select Device

Device Type

Select whether to adjust the flow on a transmission line/transformer or an interface. All devices must already be defined in the case.

Device Identifier

Specify the near bus, far bus, and circuit identifier for a branch or the interface name and number for an interface. Branches will be monitored in the near bus to far bus direction and interfaces will be monitored in the direction in which they are defined to be monitored.

Present Flow

Present real power flow on the selected device.

Desired Flow

Desired real power flow on the selected device. The difference between the Desired Flow and the Present Flow (Desired Flow – Present Flow) will be the flow change for which injection changes will be calculated.

Available Injection Groups

Injection Group Identifier

Specify the injection group name and number that contains the loads and generators whose injection can be changed to reach the Desired Flow. The injection group must already be defined in the case. The injection group definition is used simply for selecting the group of elements to be used in the calculations; the participation factors defined with the participation points in the injection group are not used in the Line Loading Replicator tool.

Only Include AGCAble Generation and Load

If checked, only those loads and generators in the selected injection group whose AGC status is YES will be included in the calculations.

Calculation Method

Select the method used to calculate the distribution factors used to determine real power injection changes.

Max and Min Load Limits for Injection Changes

Use Max and Min Load Values

If checked, the maximum and minimum load values will come from the maximum and minimum values defined with each individual load record.

Set Max and Min Load Values

Click this button to show the Load Records Case Information Display. The maximum and minimum load values can be defined by displaying the Max MW and Min MW fields and setting the values as appropriate.

Use Multiplier on Present Value

If checked, the minimum and maximum value for each load will be determined by applying the Min Multiplier and Max Multiplier to the present load value.

Calculate Injection Changes

Click this button to calculate the injection changes required to meet the Desired Flow on the selected device.

Injection Changes

This is a case information display that will provide a summary of the injection changes needed, and the elements that can effect these changes, in order to meet the Flow Achieved on the selected device. The Flow Achieved will differ from the Desired Flow if there are not enough injection changes available to meet the Desired Flow.

The results are reported in terms of injection. For generators, a positive injection means an increase in generator output and a negative injection means a decrease in generator output. For loads, the opposite is true; a positive injection means a decrease in load and a negative injection means an increase in load.

Injection Change, Present Injection, and New Injection fields will be shown by default. These Present Injection and New Injection fields are both calculated based on the present injection of the given element with the New Injection value also being dependent on the Injection Change value. The Present Injection and New Injection values will be updated any time that the present injection for an element changes in the power system. This is important to keep in mind if making any changes to the power flow case while the Line Loading Replicator dialog is open.

Injection changes are calculated so that generator and load limits are enforced. Which load limits are used is determined in the Max and Min Load Limits for Injection Changes option settings. The generator limits used are the minimum and maximum limits defined with each generator. These limits can be accessed from the Generator Case Information Display. The load and generator limits can also be displayed in the Injection Changes table by adding the Min MW and Max MW fields to the table.

Total Injection Increase/Decrease

This value is the amount of injection increase and decrease required to meet the Flow Achieved. The net injection will be zero.

Flow Achieved

Flow amount that can be achieved by implementing the Injection Changes listed. This value will differ from the Desired Flow if there are not enough injection changes available to meet the Desired Flow.

Implement Injection Changes

Click this button to make changes to the power flow case to match the calculated Injection Changes. Automatic generation control (AGC) and phase shifter control are disabled for the entire case when choosing to implement changes.

Implement Injection Changes and Solve Power Flow

Click this button to make changes to the power flow case to match the calculated Injection Changes and then solve the power flow. The power flow is solved with the settings that are specified in the Power Flow Solution Options specified with Simulator Options. When choosing to implement changes, these options are updated so that automatic generation control (AGC) and phase shifter control are disabled globally for the case. The Present Flow value is updated after the completion of the power flow solution.