OMICRON Magazine

Magazine | Issue 2 2023 The advantages of testing protection systems using virtual IEDs include the following details: › There is no need for spare IEDs at a central location › No physical test sets are required › There are no test set output power limitations › The number of usable test signals is unlimited › Intensive tests can be run without stressing physical IEDs › Troubleshooting is sped up › Test quality is increased Whether physical or virtual, proper protection system validation usually requires precise transients to be injected into the system under test. A wide range of test cases are of interest when comprehensively validating a protection system. Depending on the system under test, these may include changing infeed and load conditions, circuit breaker events, stability tests with faults outside the protected zone, and various fault scenarios inside the protected zone. Early industry attempts at testing virtual protection systems included replaying COMTRADE files. COMTRADE files may originate from a disturbance recorder and can be created by protection testing solutions. However, this approach has several limitations. Only a fraction of the relevant power system events are usually available to a system operator as a COMTRADE file originating from a disturbance recorder. Creating COMTRADE files for each test case and importing these into the virtual IED platform is time-consuming. More importantly, testing virtual protection systems by replaying COMTRADE files does not allow the test system to react dynamically to the protection system’s response. «Testing protection systems using virtual IEDs allows the design and logic of the protection system to be validated before the physical IEDs are installed.» 7