When SARA runs a fault with a contingency that calls for the mutual line to be outaged and grounded at both ends it means the full line – not just the first segment. This is to replicate what would be commonly done in real life. However, this is a little tricky to accomplish in ASPEN, which a user may want to do to cross-check the results given by SARA. The following example uses the SAMPLE30.olr provided by ASPEN.
Let’s say your primary line goes from Ohio to Nevada, and the line from Nevada to Arizona is mutually coupled.
Now we want to do a Remote Bus fault (at Nevada) and outage and ground the mutually coupled line (Nevada to Arizona).
You may be tempted to perform a Classical Bus Fault at Nevada, check “With Outage” and press Simulate…
…but will then find that the option is to take the first segment out, not the full line…
…and result in the following simulation:
In order to simulate the full line out and grounded at both ends such as what SARA is doing, we will need to do something completely different: a Simultaneous Fault.
In the tool bar, click Faults -> Specify Simultaneous Faults. The following window will open:
This window will allow you to specify multiple simultaneous occurrences – faults, outages, etc. On the right, click Add.
First, we add our Remote Bus fault. Choose bus, choose NEVADA (132 kV), choose 1LG, and press OK.
Now we have our remote bus fault, press Add again and we will begin to outage and ground both ends of the mutual line.
We don’t have an explicit way to do this but we have the tools to accomplish what we need. When a line is grounded on one end it is nothing more or less than an intentional three phase to ground fault. A Line-End fault will work well for us here because it has the end-open built in. Choose Line-End, Nev/Ariz Tap to Arizona, 3LG, and press OK.
Press OK, then Add another and do the end that is Nev/Ariz Tap to Nevada, and press OK. Your Simultaneous Faults window should now look like this:
You may now press Simulate, and you will see that a Remote Bus fault (1LG) has been simulated at NEVADA with Line-End faults (3LG) at each end of the line between NEVADA and ARIZONA, effectively simulating a full line outaged and grounded at both ends.
