SimPowerSystems

Three-Phase Breaker

Implement a three-phase circuit breaker opening at the current zero crossing

Library

Elements

Description

The Three-Phase Breaker 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 Breaker block uses three Breaker blocks connected between the inputs and the outputs of the block. You can use this block in series with the three-phase element you want to switch. See the Breaker block reference pages for details on the modeling of the single-phase breakers.

If the Three-Phase Breaker block is set in external control mode, a control input appears in the block icon. The control signal connected to this input must be either 0 or 1, 0 to open the breakers, 1 to close them. If the Three-Phase Breaker block is set in internal control mode, the switching times are specified in the dialog box of the block. The three individual breakers are controlled with the same signal.

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

Dialog Box and Parameters

Initial status of breakers

The initial status of the breakers. The initial status is the same for the three breakers. Depending on the initial status, the icon shows a closed contact or an open contact.

Switching of phase A

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

Switching of Phase B

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

Switching of phase C

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

Transition times(s)

The Transition times(s) parameter is not visible in the dialog box if the External control of switching times parameter is selected.

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

External control of switching times

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

Breakers resistance Ron

The internal breaker resistances, in ohms (). The Breaker resistance Ron parameter cannot be set to 0.

Snubbers resistance Rp

The snubber resistances, in ohms (). Set the Snubber resistance Rp parameter to inf to eliminate the snubbers from the model.

Snubbers capacitance Cp

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

Measurements

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

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

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 is identified by a label followed by the block name and the phase:

Measurement	Label
Breaker voltages	Ub <block name> /Breaker A: Ub <block name> /Breaker B: Ub <block name> /Breaker C.
Breaker currents	Ib <block name> /Breaker A: Ib <block name> /Breaker B: Ib <block name> Breaker C.

Inputs and Outputs

The three inputs A, B, and C and the three outputs a, b, and c are the breaker terminals. Breaker A is connected between input 1 and output 1, breaker B is connected between input 2 and output 2, and breaker C is connected between input 3 and output 3. If the Three-Phase Breaker block is set in external control mode, the Simulink input 4 appears and it is used to control the opening and closing of the three internal breakers.

Example

See the power_3phlinereclose and power_3phseriescomp demos for circuits using the Three-Phase Breaker block.

See Also

Breaker, Multimeter, Three-Phase Fault

Synchronous Machine

Three-Level Bridge