How to change Three Phase Parallel RLC load at a particular Simulation time?

In my Simulink-Power system block, using Three Phase Parallel RLC Load and running simulation for 20s. At the start of simulation ,the load is set to 322MW. After 2 seconds of Simulation, the load should be changed to 322kW without interrupting the simulation . How to do it?

[GEORGE ALDERSON]

did you figure out how to do it?

Answer 1

[Aastha]

Hi @SanthoshKumar C,

I understand that you are working with a Simulink-Power Systems model where a Three-Phase Parallel RLC Load initially draws 322 MW, and you want to dynamically reduce this load to 322 kW after 2 seconds based on the simulation time.

To implement this, you can use a combination of a Simulink “Step” block, a Simscape “SPST Relay”, and a Simscape “Circuit Breaker” block to toggle between the two different load values. Please refer to the steps below:

1. Configure the “Step” block to switch from 0 to 1 at t = 2 seconds. This will serve as the control signal to trigger the load change.

2. Connect the input of the “Relay” and “Circuit Breaker” blocks to a common input, and connect the output of the “Circuit Breaker” block to the 322 MW load, and the output of the “Relay” block to the 322 kW load. Set the threshold of both blocks to 0.5.

3. The relay acts as a logical threshold detector. With the threshold set at 0.5, it allows current flow when the control input is greater than the threshold. The “Circuit Breaker” breaks the current flow when the input exceeds the threshold.

In this way, you can dynamically switch between the two loads.

For more information on the above mentioned blocks, you can refer to the MathWorks documentation linked below:

• Circuit Breaker: https://www.mathworks.com/help/sps/ref/circuitbreaker.html
• SPST Relay: https://www.mathworks.com/help/sps/ref/spstrelay.html

I hope this helps!