Min./Max. Voltage calculation

The min./max. voltage calculation is used to define the minimum and maximum voltages occurring in a grid based on two worst-case scenarios:

• High Load: this scenario will be used to run a power flow calculation on all grids to define the minimum voltage of each grid.
• Low Load: this scenario will be used to run a power flow calculation on all grids to define the maximum voltage of each grid.

The minimum and maximum voltages $v_{min}$ and $v_{max}$ and the voltage drop/rise ${\mathrm{\Delta }}_{min}$ and ${\mathrm{\Delta }}_{max}$ from the network feeder to the bus that experiences the minimum/maximum voltage are saved for each grid.

The worst-case scenarios can be defined on the Grid Data Updates page or when manually starting the min./max. voltage calculation.

INFO

The following features can take advantage of this through the setting Check voltage violations in sibling grids:

• Hosting Capacity
• Connection Request

Check voltage violations in sibling grids

Sibling grids are grids that are electrically connected with each other only on the primary side of the transformer. For low-voltage grids this means a connection through the medium voltage grid.

Voltage violations in a sibling grid can occur under certain circumstances when adding additional load/generation in the grid that is to be evaluated or are already present in the base case.

When running a Hosting Capacity or Connection Request calculation the voltage violation in the sibling grids are considered as follows:

• The medium voltage grid is attached to the evaluated grid, including the slack bus of the sibling grids.
• The calculated voltage at the slack buses of the sibling grids must be within the range $[{\underset{―}{v}}_{min}+{\mathrm{\Delta }}_{min},{\bar{v}}_{max}-{\mathrm{\Delta }}_{max}]$, where ${\underset{―}{v}}_{min}$ and ${\bar{v}}_{max}$ are the operational limits for overvoltage and undervoltage and ${\mathrm{\Delta }}_{min}$ and ${\mathrm{\Delta }}_{max}$ is the calculated voltage drop/rise from the min./max. voltage calculation.

If the calculated voltage at the slack bus falls outside of the range this means that a voltage violation in the sibling grid occurs (under the assumption of linearity).