CEE Relays Ltd

Tel:   +44 1753 576477    Fax: +44 1753 825661
FAQs: "System Topology" Error when running Balanced System Studies
When attempting to run any kind of balanced system study (Load Flow, Short Circuit, etc.) an error is generated stating "System Topology not Defined": 
System topology error
(Left): "System Topology" errors are usually confined to very simple projects with few components. 
This example shows a typical System Topology error message, along with a statement that the selected system study (IEC analysis in this case) cannot be run. 
Errors like this usually occur when a very simple system has been defined without any cables or loads, like the one above.  In this example there are only two generators linked to a bus-bar and no other components.  There are two possible solutions to this problem.  The first is to insert cables between the generators and the bus-bar.  Make sure that the cable lengths are defined. Cable impedance may be zero, although this will generate a warning message and PTW will default to a very low impedance. 
system topology solution 1
(Right): Solution 1. Inserting cables after the generator components allows the balanced system study to run.
Note that in this example the project has been named "System topology error"; hence the file name in the project pathway. 
The second alternative solution is to insert a cable and a load connected to the bus-bar.  As before, the cable must have a defined length; ideally an impedance too.  The load must be configured with a kVA rating (within the capability of the generators connected to the network): 
system topology solution 2