Verification of the Operational Performance of AFDDs Under Ground Fault Conditions

The sequential arc discharge occurs as a result of damage to the conductive conductor (often referred to as “poor contact”). This type of discharge is particularly difficult to detect, posing a significant hazard. During a sequential arc discharge, the current flowing in the circuit decreases, and a conventional circuit breaker will not activate in response to this reduction in current. In contrast, parallel arc discharges, such as “phase-neutral” and “phase-ground,” are accompanied by an increase in circuit current. The time to ignition can be so short that it may not be sufficient for a standard protective device to disconnect the damaged section of the circuit. To eliminate fires caused by arc discharges, a specialized protection device for arc discharges and spark gaps has been developed and successfully implemented. This article presents a laboratory test bench designed to evaluate the performance of protection devices against parallel arc discharges and spark gaps under ground fault conditions. This test bench allows for the assessment of devices' responsiveness during ground faults, with the potential for subsequent certification. The conducted tests demonstrate the necessity of establishing mandatory requirements for these devices to standardize their operational algorithms. It has been determined that the protection device can effectively disconnect parallel arc discharges to ground, thereby enhancing the safety of electrical networks up to 0.4 kV and reducing the incidence of fires caused by violations of electrical equipment installation and operation standards.