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Transient Surges and Surge Suppression Technologies Joe Kenney International Business Development Manager Caribbean, Latin America and Asia Pacific Outside & Inside Causes of Transients Outside Causes Inside Causes 1. Environmental 1. Internal Power Switching i.e. Lightning 2. Power Company i.e. Grid Switching 3. Other Users Power Quality Decreases as the Number of Other Users Sharing the Power Feed Increases i.e. Air Conditioning, Refrigeration Systems, Florescent Light Ballasts, Elevators, Co-pay Machines to Coffee Pots, Various Types of Motor Starter Contactors All Suppressors Should Be Tested with Both Long Waveforms (10/1000 µs) and Short Waveforms (8/20 µs) Why? • AC switching transients (10/1000 µs) occur more often than lightning (8/20 µs). • The suppressor will need to dissipate 50 times more energy in the real world (10/1000 µs) than it will with the 8/20 µs waveform test. Test Current Waveforms Comparison (Per IEEE C62.41-1991) 3000 IP Represents amperage diverted by the SPD in a 8/20 surge 8/20 µsec (shortwave) 10/1000 µsec (longwave) 2500 Represents amperage diverted by the SPD in a 10/1000 surge 2000 The SPD will dissipate approximately 50 times more power with the 10/1000 than the 8/20 waveform test 1500 1000 500 0 10 100 200 300 400 500 600 Time (µs) 700 800 1000 Requirements for a Surge Protective Device (SPD) • Response Time • Voltage Protection Level • Surge Current • Power Dissipation • Disturbance Free Operation • Performance Reliability • Operating Life • Lead Length Voltage Protection Level For 120 VAC Nominal (L-N) (100 to 132 VAC) 500 Failure Level 400 Degradation, Errors & Possible Damage Level 300 Protection Level 200 170 0 Time (ms) Power Dissipation Comparison For 120 VAC Nominal (L-N) (100 to 132 VAC) 600 Higher voltage limiting suppressor must dissipate the power in area 1 Lower voltage limiting suppressor must dissipate the power in areas 1 & 2 400 300 120 0 Time (ms) Technology Comparison *SASD Filter MOV Gas Tube Yes Yes No No Yes Yes No No Expected Life Long Long Degrade w/use Degrade w/use Reliable Performance Yes No No No <130% Frequency Dependant > 130% >130% Non Degrading Response Time <5ns Voltage Protection Level * SASD results based on Lattice Matrix or ASAT design technology Conclusion • Eliminating transient overvoltages: – reduces operation costs – reduces downtime, repair & maintenance costs • A surge suppressor is not an insurance policy, rather an assurance that your system won’t have problems. Insurance policies cover repair costs after failure, not losses related to downtime which can far exceed repair costs. • By evaluating overall system cost & investment, it’s clear that transient overvoltage suppression equipment must become an integral part of any electronic system.