Three-Phase Fault

Implement programmable phase-to-phase and phase-to-ground fault breaker system

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Libraries:
Simscape / Electrical / Specialized Power Systems / Power Grid Elements

Description

The Three-Phase Fault block implements a three-phase circuit breaker where the opening and closing times can be controlled either from an external Simulink^® signal (external control mode), or from an internal control timer (internal control mode).

The Three-Phase Fault block uses three Breaker blocks that can be individually switched on and off to program phase-to-phase faults, phase-to-ground faults, or a combination of phase-to-phase and ground faults. The arc extinction process of the Three-Phase Fault block is the same as for the Breaker block. See the Breaker block for details on the modeling of the single-phase breakers.

The ground resistance Rg is automatically set to 10⁶ ohms when the ground fault option is not programmed. For example, to program a fault between the phases A and B you need to select the Phase A and Phase B block parameters only. To program a fault between the phase A and the ground, you need to select the Phase A and Ground parameters and specify a small value for the ground resistance.

If the Three-Phase Fault block is set in external control mode, a control input appears in the block icon. The control signal connected to the fourth Simulink input must be either 0, which opens the breakers, or any positive value, which closes the breakers. For clarity, a 1 signal is commonly used to close the breakers. If the Three-Phase Fault block is set in internal control mode, the switching times and status are specified in the dialog box of the block.

Series Rs-Cs snubber circuits are included in the model. They can be optionally connected to the fault breakers. If the Three-Phase Fault block is in series with an inductive circuit, an open circuit or a current source, you must use the snubbers.

Examples

Three-Phase Series Compensated Network

The use of three-phase blocks to study transients on a series-compensated 735-kV transmission system.

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Ports

Input

com — Control input

Simulink signal

Control input for the three-phase fault.

Dependencies

To enable this port, select the External parameter.

Conserving

A — Phase A terminal

specialized electrical

Specialized electrical conserving port associated with the phase A terminal.

B — Phase B terminal

specialized electrical

Specialized electrical conserving port associated with the phase B terminal.

C — Phase C terminal

specialized electrical

Specialized electrical conserving port associated with the phase C terminal.

Parameters

To edit block parameters interactively, use the Property Inspector. From the Simulink Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Initial status — Initial status of fault breaker

0 (default) | scalar

Initial status of the fault breaker. You can also start the simulation in steady state with the fault initially applied on the system.

Phase A — Fault switching of phase A

on (default) | off

If selected, the fault switching of phase A is activated. If not selected, the breaker of phase A stays in the status specified in the Initial status parameter.

Phase B — Fault switching of phase B

on (default) | off

If selected, the fault switching of phase B is activated. If not selected, the breaker of phase B stays in the status specified in the Initial status parameter.

Phase C — Fault switching of phase C

on (default) | off

If selected, the fault switching of phase C is activated. If not selected, the breaker of phase C stays in the status specified in the Initial status parameter.

Ground — Fault switching of phase C

on (default) | off

If selected, the fault switching of ground is activated. A fault to the ground can be programed for the activated phases. For example, if the Phase C and Ground parameters are selected, a fault to the ground is applied to the phase C. The ground resistance is set internally to 1e6 ohms when the Ground parameter is not selected.

Switching time (s) — Vector of switching times

[1/60 5/60] (default) | vector of scalars

Specify the vector of switching times when using the block in internal control mode. At each transition time the selected fault breakers opens or closes depending to their initial state.

Dependencies

To enable this parameter, clear the External parameter.

External — Option to enable external control signal

off (default) | on

If selected, adds a fourth input port to the block for an external control of the switching times of the fault breakers. The switching times are defined by a Simulink signal (0-1 sequence).

Fault resistances Ron — Internal resistance of phase fault breakers

0.001 (default) | positive scalar

Internal resistance, in ohms (Ω), of the phase fault breakers. This parameter cannot be set to 0.

Dependencies

Ground resistance Rg — Ground resistance

0.01 (default) | positive scalar

Ground resistance, in ohms (Ω). This parameter cannot be set to 0.

Dependencies

To enable this parameter, select the Ground parameter.

Snubbers resistance Rs — Snubber resistance

1e6 (default) | nonnegative scalar

Snubber resistance, in ohms (Ω). Set this parameter to inf to eliminate the snubbers from the model.

Snubbers capacitance Cs — Snubber capacitance

inf (default) | nonnegative scalar

Snubber capacitance, in farads (F). Set this parameter to 0 to eliminate the snubbers, or to inf to get resistive snubbers.

Measurements — Option for measurements

None (default) | Fault voltages | Fault currents | Fault voltages and currents

Select Fault voltages to measure the voltage across the three internal fault breaker terminals.

Select Fault currents to measure the current flowing through the three internal breakers. If the snubber devices are connected, the measured currents are the ones flowing through the breakers contacts only.

Select Fault voltages and currents to measure the breaker voltages and the breaker currents.

Default is None.

Place a Multimeter block in your model to display the selected measurements during the simulation. In the Available Measurements list box of the Multimeter block, the measurements are identified by a label followed by the block name and the phase:

Measurement	Label
Fault voltages	Ub <block name> /Fault A:
Fault currents	Ib <block name> /Fault A:

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced before R2006a