Relay testing is the process of verifying that protective relays are calibrated correctly and functioning accurately. Commissioning, on the other hand, is the final stage that confirms the entire integration of relays within the system's protection scheme before the system goes live. This happens because the main function of protection devices is related to operation under fault conditions so these devices cannot be tested under normal operating conditions. This problem is. DIGSI 5 is the SIEMENS engineering tool for parameterization, commissioning and operating all SIPROTEC 5 protection relays. Then you can work with all of the devices in a substation in one project. ) Practical sections with testing of the relays (ABB REG670, MiCOM P441, MiCOM P123,. )This is why protection relays must undergo thorough tests throughout their entire lifecycle – from development and manufacturing to commissioning and regular maintenance during operation. Protection relays are critical for detecting faults, initiating protective actions, and isolating faulty sections of the. As a Relay Protection Engineer, your work in relay testing and commissioning is critical to ensuring system safety and continuity.