Transient Surges and Surge Suppression Technologies

Joe KenneyInternational Business Development Manager

Caribbean, Latin America and Asia Pacific

Outside & InsideCauses of Transients

Outside Causes

1. Environmental

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

Inside Causes

1. Internal Power Switching

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)

• 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.

Why?

Test Current Waveforms Comparison(Per IEEE C62.41-1991)

3000

2500

2000

1500

1000

500

010 100 200 300 400 500 600 700 800 1000

8/20 µsec (shortwave)

10/1000 µsec (longwave)

Represents amperage divertedby the SPD in a 8/20 surge

Represents amperage divertedby the SPD in a 10/1000 surge

The SPD will dissipate approximately50 times more power with the 10/1000 than the 8/20 waveform test

Time (µs)

Cur

rent

(I)

IP

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 LevelFor 120 VAC Nominal (L-N)

(100 to 132 VAC)

Time (ms)

170

200

300

400

500

0

Failure Level

Degradation, Errors &Possible Damage Level

Protection LevelVol

tage

Power Dissipation ComparisonFor 120 VAC Nominal (L-N)

(100 to 132 VAC)600

400

300

120

Lower voltage limiting suppressormust dissipate the power in areas 1 & 2

Higher voltage limiting suppressor must dissipate the power in area 1

0Time (ms)

Vol

tage

Technology Comparison

Non Degrading

Response Time <5ns

Expected Life

Reliable Performance

Voltage Protection Level

*SASD

Yes

Yes

Long

Yes

<130%

Filter

Yes

Yes

Long

No

Frequency Dependant

MOV

No

No

Degrade w/use

No

> 130%

Gas Tube

No

No

Degrade w/use

No

>130%

* SASD results based on Lattice Matrix or ASAT design technology

• 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.

Conclusion