From relay test sets to power quality analyzers, oscilloscopes, and disturbance recorders, these tools provide insights into relay behavior, waveforms, system anomalies, and fault events. Debugging a relay model can be advantageous when having trouble with the model. There are multiple cases where you have to debug a relay model. In both cases, you have to look into the. 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. From a technician's perspective, master the unique skill of testing protection. Relay protection systems are the unsung heroes of electrical networks.