# Switch¶

## Create Function¶

pandapower.create_switch(net, bus, element, et, closed=True, type=None, name=None, index=None, z_ohm=0)

Adds a switch in the net[“switch”] table.

Switches can be either between to buses (bus-bus switch) or at the end of a line or transformer element (bus-elememnt switch).

Two buses that are connected through a closed bus-bus switches are fused in the power flow if the switch es closed or separated if the switch is open.

An element that is connected to a bus through a bus-element switch is connected to the bus if the switch is closed or disconnected if the switch is open.

INPUT:

net (pandapowerNet) - The net within this transformer should be created

bus - The bus that the switch is connected to

element - index of the element: bus id if et == “b”, line id if et == “l”, trafo id if et == “t”

et - (string) element type: “l” = switch between bus and line, “t” = switch between bus and transformer, “b” = switch between two buses

OPTIONAL:

closed (boolean, True) - switch position: False = open, True = closed

type (int, None) - indicates the type of switch: “LS” = Load Switch, “CB” = Circuit Breaker, “LBS” = Load Break Switch or “DS” = Disconnecting Switch

z_ohm (float, 0) - indicates the resistance of the switch, which has effect only on

bus-bus switches, if sets to 0, the buses will be fused like before, if larger than 0 a branch will be created for the switch which has also effects on the bus mapping

name (string, default None) - The name for this switch

OUTPUT:

sid - The unique switch_id of the created switch

EXAMPLE:

create_switch(net, bus = 0, element = 1, et = ‘b’, type =”LS”, z_ohm = 0.1)

create_switch(net, bus = 0, element = 1, et = ‘l’)

## Input Parameters¶

net.switch

 Parameter Datatype Value Range Explanation bus* integer index of connected bus name string name of the switch element* integer index of the element the switch is connected to: - bus index if et = “b” - line index if et = “l” - trafo index if et = “t” et* string “b” - bus-bus switch “l” - bus-line switch “t” - bus-trafo “t3” - bus-trafo3w switch element type the switch connects to type string naming conventions: “CB” - circuit breaker “LS” - load switch “LBS” - load break switch “DS” - disconnecting switch type of switch closed* boolean True / False signals the switching state of the switch

*necessary for executing a power flow calculation.

## Electric Model¶

Bus-Bus-Switches:

Two buses that are connected with a closed bus-bus switches are fused internally for the power flow, open bus-bus switches are ignored:

This has the following advantages compared to modelling the switch as a small impedance:

• there is no voltage drop over the switch (ideal switch)

• no convergence problems due to small impedances / large admittances

• less buses in the admittance matrix

Bus-Element-Switches:

When the power flow is calculated internally for every open bus-element switch an auxilary bus is created in the pypower case file. The pypower branch that corresponds to the element is then connected to this bus. This has the following advantages compared to modelling the switch by setting the element out of service:

• information about switch position is preserved

• difference between open switch and out of service line (e.g. faulty line) can be modelled

Closed bus-element switches are ignored: