This example shows the interface between Simscape and Simscape Power Systems Specialized Technology to design a breaker model.
There are two similar circuits shown in parallel. The top circuit model illustrates tripping of a circuit breaker protecting a 240 V residential distribution circuit. The Circuit Breaker model is built with Simscape Power Systems blocks. The circuit below is identical in all respects, but for a Simscape model of the Circuit Breaker.
Figure 1: In the top model the Circuit Breaker is modeled using two Simscape Power Systems blocks (Ideal Switch and Current Measurement) and associated logic implemented with Simulink blocks while the lower model uses two Simscape blocks (Switch and Current Sensor).
The top circuit illustrates tripping of a circuit breaker in a 240 V residential distribution circuit. Initially, the 240 V circuit feeds a 10 kW load. Then, at t=0.05 s, a second load (10 kW, 5 kvar)is switched on, causing current to exceed the trip setting (100 A). Current is interrupted at its first zero-crossing after the trip current has been exceeded. Finally, Load 1 is reconnected by resetting the circuit breaker at t= 0.2 s.
The bottom circuit is using the Simscape Interface Element block of powerlib to connect a Simscape circuit breaker model to the Simscape Power Systems circuit. The Simscape breaker block is a modified version of the breaker model found in ssc_circuitbreaker model.
On running the model we can observe that the two different implementations of the circuit breaker device produce the same circuit breaker current and voltage.
Figure 2: Results obtained from the Simscape Power Systems Breaker model are superimposed with results from Simscape Breaker model. Note that the breaker current is interrupted at zero-crossing after the 100 A trip current setting has been exceeded.
Using the Simscape Interface blocks of powerlib, it is possible to create any custom block not provided with Simscape Power Systems, in Simscape, and then interface it seamlessly with a Simscape Power Systems circuit.