SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 1 Poor Power Quality as an EMI Problem M. McClelland Anteon Corporation

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 2 What is Power Quality (PQ)? Power Quality is “The concept of powering and grounding electronic equipment in a manner that is suitable to the operation of that equipment and compatible with the premise wiring system and other connected equipment.” © IEEE Recommended Practice for Powering and Grounding Sensitive Electronic Equipment IEEE Std

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 3 How is Poor PQ an EMI Problem? EMI is: “Any electromagnetic disturbance which interrupts, obstructs, or otherwise degrades or limits the effective performance of electronics/electrical equipment. It can be induced intentionally, as in some forms of electronic warfare, or unintentionally, as a result of spurious emissions and responses, intermodulation products, and the like.” Federal Telecommunication Standard 1037 Failure to power and ground electronic systems in a manner suitable to the operation of that equipment results in poor PQ. – Poor PQ in turn may result in EMI related issues which may cause system data disruption, hardware stress, and hardware destruction*. *IEEE Std

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 4 Where to find PQ events ? Typical Frequency Spectrum – PQ refers to conducted energy, both normal and common-mode occurring within the VLF through VHF bands, 30 HZ through 200 MHz – May also be radiated energy ° < 50 kV/m, < 200 kHz ° 200 kHz PQ anomalies, because of the higher voltages and currents available, can instantly destroy valuable electronic equipment.

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 5 Doesn’t MIL-STD-461 Cover PQ Effects? YES & NO (Examples) – Yes - Radiated transients – No - Conducted Transients - manual switching* MIL-STD-1399 Interface Standard for Shipboard Systems, Section 300A, Electric Power, Alternating Current covers some transient requirements and some grounding requirements. MIL-STD-464 Electromagnetic Environmental Effects Requirements for Systems addresses radiated emissions > 10 kHz. * MIL-STD-461E Append. A

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 6 Sample Manual Switching Transient(s) DDG-82 Mk. 41 Aft VLS Power On Cycle

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 7 Navy Power Quality Indicators Combatants - DDG-51 Class (DDG-51-DDG- 78): 339 unexplained power supply failures –181 failures on Mk 41 VLS alone Aviation - New Automatic Test Equipment - CASS - hardware failures at five sites, FY 97-FY 01 $14,851,298 –Includes material costs only.

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 8 PQ Sources of Concern “The Navy Today” Sensitive electronic loads returning noise, harmonics, and switching transients back into the facility power source, via the power and grounding leads, degrading the source power and grounding system. –Internal induced damage or degradation to systems and components. Legacy power distribution systems do not support 21st century sensor/weapons systems –Electronics revolution requires a “better” power quality solution

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 9 PQ Sources of Concern Platform/Facility power source anomalies conducted by the power and grounding leads resulting in equipment degradation and failures. - Externally induced damage or degradation

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 10 PQ/EMI Classifications * Type I, Signal-Data Disruption Type II, Gradual Hardware Stress and Latent Failures Type III, Immediate Hardware Destruction *IEEE Std

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 11 Type I - Signal-Data Disruption Digital Signal Circuits susceptible to voltage surge interference via: – Conduction – Inductive and Capacitive coupling – Electromagnetic radiation “1” & “0” Logic State is relatively stable, when latched. If interference is coincident with state transition… then a 50/50% chance of error can result. “Lock up”of a CPU due to a forced “truth table” violation is possible. TT violation can exceed junction operating temperatures. Erratic state transitions often blamed on bad software/hardware

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 12 Type I - Signal-Data Disruption (cont’d) Surge Paths can be: – Line Filters ° Low Pass LC network filters with line-to-ground (chassis) shunt elements. Shunt capacitors are restricted to <0.1 uF by MIL-STD- 461E , and MIL-STD °This requirement is seldom enforced ! – Metal Oxide Varistor (MOV) based Transient Voltage Surge Suppressors (TVSS) configured in shunt mode (line-chassis) ° > V ON, Supply phase is connected to chassis. ° This appears to conflict with intent MIL-STD-461E

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 13 Type II - Gradual Hardware Stress/Latent Failures Repeated Truth Table violations caused by voltage surges (Voltage Overstress- EOS) can weaken chip substrate due to thermal overstress - breaks down insulating oxides. 2.5 VDC Logic family, oxide layers break down at 5 VDC. DC Current stress can cause accelerate substrate Electromigration, the formation of metal voids in interconnects Intel Technology Journal Q3’98

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 14 Type III - Immediate Hardware Destruction Voltage/Current overstress can cause immediate, noticeable problems This MOV rated 6/20 uSec Power Distribution components are tougher than CPU chips Failed MOV - USM-636 Internal TVSS shunt element

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 15 Type III - Immediate Hardware Destruction Common-mode shunt elements can direct couple large energy transients into system chassis - possibly causing Type I, II, or III damage Thresholds of failure of selected semiconductors Semiconductor typeDisruption energy (J) Destruction energy (J) Digital Integrated circuits Analog integrated circuits Low-noise transistors High-speed transistors and ICs from IEEE Std Table 4-6

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 16 Military Application Areas of Power Quality Warships Support Ships Aircraft Aircraft Maintenance Depots Ground Force Tactical Shelters Shore Support Facilities Typical Power Quality Analysis Software

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 17 Conclusion Poor PQ can degrade system/unit reliability and maintainability. New technology and old infrastructure fuel the need for new thinking and technology in power system engineering PQ solutions have immediate benefits: –Operational reliability improves –System Operator confidence improves –Maintenance & damage costs are reduced

SEA 53H3--VIN/PEL-04 (As of 17 Oct 01) 18 ANY QUESTIONS? ?