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I'm trying to design a Solid state circuit breaker for a 3phase AC system with a rating of 690V, 1000A. As, the stray inductance contributes to the voltage peaks in the system I'm trying to protect the power electronic devices in several fault conditions. currently I'm simulating several topologies of the same with on Simetrix. However, it is getting difficult to find practical values like stray inductance, resistance etc in the system, to get more practical results on simulations. I've been simulating with a lumped inductance of about 10mH till now. What are the several factors that I need to keep in mind while designing the same? Also, Where can I find the required values to model the circuit efficiently? enter image description here

Please let me know if the question is vague, I'll try to explain what I'm doing more clearly. This is the single phase equivalent. Ignore the values of the devices for now.

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    \$\begingroup\$ Trying to design protection at 1000A when you don't know the inductance is like trying to design brake pads when you don't know whether they'll be fitted to a bike, a car, or a truck. You need to create a specification for the maximum inductance your breaker is designed to handle before you can progress, or you risk expensive (bill of materials) over-design, or expensive (replacement under warranty) under-design. Of course if that specification matches typical power systems, then so much the better. \$\endgroup\$ – Neil_UK Apr 3 '17 at 8:40
  • \$\begingroup\$ If you could put up a diagram of your model at the moment it would give us an idea of where you have got to in your thinking and help us to help you. \$\endgroup\$ – RoyC Apr 3 '17 at 8:41
  • \$\begingroup\$ Usually we put circuit breakers (fuse, magnetic CB,..) to protect from fire caused by some solid state device failure. Now you want to use a solid state device for protection? IMO that is not gonna happen for long time yet. \$\endgroup\$ – Marko Buršič Apr 3 '17 at 8:49
  • \$\begingroup\$ @Neil_UK, Thanks for your answer. That's the problem I'm facing, I need specifications for typical power systems to start off with. I'm not trying to implement anything on hardware right now, it's just a small assignment. I'm not able to find any data for the specifications and I myself do not have sufficient experience to know the same. :/ \$\endgroup\$ – Pujitha Apr 3 '17 at 9:16
  • \$\begingroup\$ @RoyC, In the circuit I'm just switching of the circuit at a certain time and observing the transients. \$\endgroup\$ – Pujitha Apr 3 '17 at 9:25
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Start with a standard voltage level, say 33 kV (3 phase LL). Then model your load to get the 1000 A. Use a standard X/R ratio. For a system with significant motor loads - it may be around 10. In such scenarios, you may be able to neglect the line inductance.

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