In software development, regression testing refers to the repetition of test cases. This is to ensure that modifications in parts of the software that have already been tested do not lead to new errors. This approach can be applied very well to protection engineering. Here, such modifications occur more and more frequently and affect all substation components. Typical causes include changes to the network topology, parameter adaption, frequent firmware updates, shorter IED lifetimes, or simply the malfunction of a device.
This technical article describes in detail the method of regression testing in substation environments. Using this approach, test quality can be increased while reducing time. In addition, the documentation created provides an excellent basis for test certificates and knowledge management in the company.