Switch

Create Function

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

in_ka*

float

>0

maximum current that the switch can carry under normal operating conditions without tripping

*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:

alternate Text

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:

  • loading current is considered

  • 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:

alternate Text