N-1

The N-1 tool allows the network operator to analyze the grid in case of N-1 contingency.

This means that in the event of a branch failure (transformer, line or connection), the following must be ensured:

• no interruption of power supply
• voltages remain within limits
• other components are not overloaded

For each branch in the grid, the tool will disconnect the branch and then run a Power Flow Calculation. Bus voltage, branch loading violations and possible loss of loads and generators that are caused by the disconnection of this branch are recorded for each case and can be analyzed.

Grid

The N-1 contingency analysis is run on a single grid at a time. Choose the grid that should be calculated from the Grid dropdown list.

Click to start the calculation.

Grid Upgrades, Connection Request and Scenarios

Grid Upgrades and Connection Requests are applied to the grid by default depending on their status. They are part of the grid model for the duration of the simulation. The selected Grid Upgrades and Connection Requests are visualized in the grid.

To change the default selection, select or deselect the desired add-ons from the list. The selection is saved for the duration of the session, even when navigating to other simulations within the Adaptricity software. Reloading the page or clicking on the refresh button will restore the default selection.

Scenarios and Load Situations are never applied by default. They need to be specifically selected.

Settings

Click on at the top of the page to change the operational limits of the electrical components.

Number of worst cases defines how many violations will be displayed in the results table for each faulted branch.

Results

The N-1 results are visualized in the results table. A print friendly output can be created by clicking at the top of the page.

Results Table

Each row in the results table represents the result for a different Faulted Branch.

The ID column shows the ID of the Faulted Branch. Clicking on next to the branch ID will highlight that branch in the map view.

A colored square indicates one of the following states of the grid:

Status	Description
	no violations of the operational limits occur and no load/generation is lost for a fault at this branch
	some violations of the operational limits occur or load/generation is lost for a fault at this branch
	the calculation could not be carried out for a fault at this branch because the power flow did not converge

If a faulted branch causes a violation of one of the operational limits at any grid element or if the fault lead to lost load or generation, the faulted branch will be colored according to the Status color.

For each of the defined and activated operational limits in the settings, three columns are displayed in the results table:

• The ID of the grid element where the max/min value occurs. Clicking on highlights the component that observes this value.
• The value of the most severe occurrence of this parameter (max/min).
• The number of occurrences of this violation that are caused by the faulted branch.

If the faulted branch does not lead to a violation of the operational limit, the results are grayed out and the number of violations for that fault is 0.

TIP

• Sort the table by descending or ascending values by clicking on the column name.
• Filter the table by condition or by specific values by clicking next to the column name.