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Hi, all. I'm trying to analysis angle stability of machines in the system, which costs me a lot of time because I have to run dynamic simulation over and over again to find CCT (critical clearing time).

That's so I came up with an idea to run it automatically. The script isn't so hard, I guess I can deal with it, but the problem is how to realize if a system stability or not.

Manually, I could say if a system is instability by some signs, such as that machines' speeds and angles are seperated largely, or voltages drop below 0.5 (voltage stability), etc. However, defining a quantitative criteria which works for every machines in the system is not as easy.

I came some ideas for the criteria, but not so sure about them:

1. the difference between any 2 machine's angles isn't bigger than 100 degree.
2. The difference between any machine's speed and the average speed of the system must be smaller than 0.1. Average speed is calculated like this: Sum((Machine speed)*(machine inertia constant))/ (Sum Inertia constants)
3. d Delta/dt turn sign (from negative to positive or vice visa) more than once, in which Delta is the difference between angle of interested machine and reference machine.

I want to know is there any available function in pss/e that can distinguish instability system? If not, is there any other idea to make it?

Hi, all. I'm trying to analysis analyse angle stability of machines in the system, which costs me a lot of time because I have to run dynamic simulation over and over again to find CCT (critical clearing time).

That's so I came up with an idea to run it automatically. The script isn't so hard, I guess I can deal with it, but the problem is how to realize identify if a system stability or not.

Manually, I could say if a system is instability by some signs, such as that machines' speeds and angles are seperated largely, or voltages drop below 0.5 (voltage stability), etc. However, defining a quantitative criteria which works for every machines in the system is not as easy.

I came some ideas for the criteria, but not so sure about them:

1. the difference between any 2 machine's angles isn't bigger than 100 degree.
2. The difference between any machine's speed and the average speed of the system must be smaller than 0.1. Average speed is calculated like this: Sum((Machine speed)*(machine inertia constant))/ (Sum Inertia constants)
3. d Delta/dt turn sign (from negative to positive or vice visa) more than once, in which Delta is the difference between angle of interested machine and reference machine.

I want to know is there any available function in pss/e that can distinguish instability system? If not, is there any other idea to make it?