Underexplored Three-Phase Power Failure Conditions – CEU/PDH Credit Available

In avionics, widely used standards for power quality include MIL-STD-704 and RTCA DO-160. While both these standards are extremely detailed, in the area of three-phase power failure, there are enhancements that should be considered to capture the full set of failure conditions that can occur in the field or during production tests.

For example, in MIL-STD-704, it is not clear how a phase loss is defined. Although the accompanying handbook (MIL-HDBK-704) does clarify the fault definition (as a zero-volt potential) it is also likely that the fault can be caused by an open-circuit condition, which is not covered. Also not covered is the application of power to the Unit Under Test (UUT) with a pre-existing fault condition. DO-160 has a similar issue with the phase fault definition, but it does cover some cases where the UUT is energized with a pre-existing fault. Neither specification covers the loss of the neutral connection for wye loads.

Suggested updates to both standards are discussed, along with examples describing scenarios where a UUT may pass the DO-160 and/or MIL-STD-704 phase loss methods but fail under conditions likely to occur in the field or during production test. Design mitigation techniques to prevent damage are also covered.

Speaker(s): James Colotti,

Farmingdale, New York, United States, Virtual: https://events.vtools.ieee.org/m/270985