BusFault

Represents an impedance fault at a bus. This device can exist in two states, on or off, controlled by the user. Following a state change, generally the solver needs to be reset as this is a discrete event.

Model Parameters

Symbol	Units	JSON	Description	Typical Value	Note
\(R\)	[p.u.]	R	Fault resistance
\(X\)	[p.u.]	X	Fault reactance
\(U\)	[boolean]	state0	Initial fault status		JSON boolean; true puts the fault on. Changed at run time through setStatus().

Parameter Validation

None.

Model Derived Parameters

\[\begin{split}\begin{aligned} G &=\dfrac{R}{R^2+ X^2} \\ B &= -\dfrac{X}{R^2 + X^2}\\ \end{aligned}\end{split}\]

Model Ports

Name	Port	Init	Description
bus	Bus	Known	Required bus where the fault is applied
control_signal	Input	N/A	Accepted by the parser but not read by the model; fault status is set through state0 and setStatus()

Model Variables

Internal Variables

Differential

None.

Algebraic

Symbol	Units	Description	Note
\(I_r\)	[p.u.]	Terminal current, real component	Read by bus
\(I_i\)	[p.u.]	Terminal current, imaginary component	Read by bus

External Variables

Differential

None.

Algebraic

Symbol	Units	Description	Note
\(V_r\)	[p.u.]	Terminal voltage, real component	owned by bus object
\(V_i\)	[p.u.]	Terminal voltage, imaginary component	owned by bus object

Model Equations

Internal Equations

Differential

None.

Algebraic

\[\begin{split}\begin{aligned} 0 &= -I_r + U (-G V_r + B V_i) \\ 0 &= -I_i + U (-B V_r - G V_i) \end{aligned}\end{split}\]

External Equations

The fault currents are added to the connected bus residuals:

\[\begin{split}\begin{aligned} I_r^{\mathrm{bus}} &\leftarrow I_r^{\mathrm{bus}} + I_r \\ I_i^{\mathrm{bus}} &\leftarrow I_i^{\mathrm{bus}} + I_i \end{aligned}\end{split}\]

Initialization

The initial fault status and bus voltage determine the terminal currents:

\[\begin{split}\begin{aligned} U &\leftarrow \text{initial fault status} \\ I_r &\leftarrow U(-GV_r+BV_i) \\ I_i &\leftarrow U(-BV_r-GV_i) \end{aligned}\end{split}\]

The derivative vector entries initialize to zero.

Monitors

Monitor	Units	Description	Note
state	[binary]	Fault status	1 when on; 0 when off
ir	[p.u.]	Fault-current real component	Added to the connected-bus residual
ii	[p.u.]	Fault-current imaginary component	Added to the connected-bus residual