Shift Factor Multiple Device Type

(In Version 21 and earlier this was called the TLR Sensitivities or Generation Shift Factors)

The Multiple Device Type selector allows you to specify a group of elements for which shift factor sensitivities will be calculated. The Multiple Device Type selection is accessible only when you choose the Multiple Elements option from the Device Type in the Shift Factor Sensitivity dialog.

Selected Devices

Select Lines/XFMRs

Select the Selected Devices option, and click on this button to open a dialog to choose the lines and transformers to be included in the calculation. Toggle the Selected field in the Lines and Transformer Case Information Display to Yes for the branches you wish to include. If the Selected field is not available in the information display, add that column to the display by right-clicking in the display and selecting Display/Column Options. The ETLR of selected Lines/XFMRs is the algebraic sum of the Shift Factors of each individual element. The WTLR uses as weight the current MW flow in the element.

Select Interfaces

Select the Selected Devices option, and click on this button to open a dialog to choose the interfaces to be included in the calculation. Toggle the Selected field in the interfaces Case Information Display to Yes for the interfaces you wish to include. If the Selected field is not available in the information display, add that column to the display by right-clicking in the display and selecting Display/Column Options. The ETLR of the selected interfaces is the sum of the Shift Factors of the interfaces that have a limit different from zero. The WTLR uses as weight the MW flow in the interface.

Overloaded Devices

Select this option to include in the multiple element shift factor calculation the branches and/or interfaces that are overloaded in the present case based on the Limit Monitoring Settings and Limit Violations Dialog. The list of the overloaded branches and interfaces is available in the Limit Monitoring Settings and Limit Violations information display.

CTG Overloaded Devices

Select this option to include in the multiple element shift factor calculation the branches and/or interfaces that were identified as overloaded by the Contingency Analysis tool. A branch or interface is included in the calculation if it has been overloaded during at least one contingency. The list of branches and interfaces identified as overloaded can be accessed from the View Results By Element page in the Contingency Analysis dialog.

The ETLR of the CTG overloaded lines and transformers is the algebraic sum of the individual shift factors. The WTLR uses as weight the Aggregate MVA Overload of each transmission line and transformer, which is defined as the sum of the MVA overload in the line or transformer across the contingencies that caused a violation in that particular line or transformer. The Aggregate MVA Overload and a related field, the Aggregate Percent Overload of a line or transformer, are measures of the weakness of that transmission line on the grid. The Aggregated MVA Overload and the Aggregate Percent Overload are line and transformer fields that can be displayed in the Case Information Display, used in Contouring, etc.

The ETLR of the CTG overloaded interfaces is the algebraic sum of the individual shift factors. The WTLR uses as weight the Aggregate MW Overload of each interface, which is defined as the sum of the MW overload of the interface across the contingencies that caused a violation in that interface. The Aggregate MW Overload and a related field, the Aggregate Percent Overload of an interface are measures of the weakness of the interface. These two interface fields can be displayed in the Case Information Display, used in Contouring, etc.

Effective Transmission Loading Relief (ETLR)

In the same manner as the shift factors represents the MW increase in an element per MW transfer, the ETLR column in the Mult. Bus Sensitivity table represents the total MW increase in all the elements in the set per MW increase of the transaction. Let us suppose that the set contains two transmission lines: A and B and assume that for a 1 MW transfer from bus i to the transactor, the flow in line A increases in 0.5 MW and the flow in line B decreases in -0.3. Then the ETLR of bus i is +0.2 since that is the total MW increase in the elements in the set. The ETLR provides a measure of the simultaneous MW change in multiple elements, and thus the overall effect in flows on the element of the set. The ETLR is a bus field that can be included in the bus Case Information Display, used in Contouring, etc.

Weighted Transmission Loading Relief (WTLR)

The WTLR column in the Mult. Bus Sensitivity table weights the sensitivities based on the flow or overload flow values of the element. It is a measure of the value of a certain bus to relief transmission loading. The buses with the highest WTLR (or lowest WTLR, depending on the transactor type) are identified as the most effective buses to mitigate transmission loading considering multiple elements. The WTLR is a bus field that can be included in the bus Case Information Display, used in Contouring, etc.