1 / 23

Surge Protection Devices

Surge Protection Devices. By: Stelios Ioannou George Bolos. Definition of Power Quality. Power Quality is measured at end-user side. Good power quality: any electrical device at the end-user side performs as expected and intended.

norah
Download Presentation

Surge Protection Devices

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Surge Protection Devices By: Stelios Ioannou George Bolos

  2. Definition of Power Quality • Power Quality is measured at end-user side. • Good power quality: any electrical device at the end-user side performs as expected and intended. • Poor power quality: If any electrical device misbehaves as a result of fluctuations in voltage waveform magnitude, frequency, harmonic distortion, symmetry, or even discontinuity in supply, then power quality is said to be “poor”.

  3. Main Power Quality Problems • Voltage Sags • Micro-Interruptions • Long Interruptions • Voltage Spikes • Voltage Swells • Voltage Unbalance • Harmonic Distortion

  4. Power Quality Problems Facts 88.5% of PQ Problems are Caused due to Transients. Source: REO, Power Quality Facts. Online Posting: www.reo.co.uk, March 21, 2005.

  5. According to EPRI(Electric Power Research Institute): • In 1999 power sags, surges and transients cost US industry over $50B in downtime. • In 2000 the figure doubled to over $100B. • In 2001 related downtime doubled again to $200B. • By comparison, the 2 day NE USA blackout of 2003 is estimated to cost theUS economy $17B.

  6. Transients and AC Power Power line transient voltage levels can be in excess of 10kV approximately compared with an office block in town which can expect levels of 3kV.

  7. IEEE Definitions of Transients (Std.4-1995) • Open-Circuit Voltage Waveform: • - Front Time: 1.2uS ± 0.36uS • Decay Time (Duration): 50uS ± 10uS Short-Circuit Current Waveform: - Front Time: 8uS (+1uS, -2.5uS) - Duration: 20uS (+8uS, -4uS)

  8. Transients Impact On Devices Source: Dranetz handbook of Power Quality.

  9. surge arresters, transient voltage surge suppressors (TVSS) Surge Diverters Surge Suppressors Surge Protection Devices

  10. Technology Profiles Surge Suppression Surge Diversion

  11. Surge Suppression Profile Source: Zero Surge Inc., “Surge Removal Filters”. Online Posting: www.zerosurge.com, March 21, 2005.

  12. Surge Suppression Waveforms Attenuated Output. Source: Zero Surge Inc., “Surge Removal Filters”. Online Posting: www.zerosurge.com, March 21, 2005.

  13. Surge Diverters Ideal V-I Clamping Characteristics.

  14. Surge Diverters Devices and Applications • Zener Diodes: Ideal clamping characteristics but poor energy limitations. • Crowbars: High energy capabilities, but power follow problem. • Metal Oxide Varistors (MOV): low stand-by currents, high short-circuit current capabilities (α diameter) , wide range of operating voltage (α to thickness), energy is evenly distributed on the volume of the MOV.

  15. Surge Diverter Waveforms MOV Clamps a 1000V Transient Voltage to 400V and a Current of 344A.

  16. Common Question Q: 400 volts let-through voltage, wouldn’t that damage an electronic device operating at 120V????? A: • 400 volts is peak value, whereas 120VRMS (170V peak). • The duration of the let-through voltage is less than 100 us.

  17. CBEBA Curve 167 us

  18. Surge Diverters Ground Contamination. MOV is sacrificial element. Surge Suppressors Attenuation of Data. Comparison

  19. Surge Protection Devices Classification And Certification • Performance • Reliability • Mode of Suppression • Underwriters Laboratories Inc. (www.ul.com)

  20. Performance • Class 1 products have suppressed voltage ratings of 330 volts. Under specified test conditions, at any transient voltage level, their measured suppressed voltages are 330 volts or less. • Class 2 products have suppressed voltage ratings of 400 volts. • Class 3 products have ratings of 500 volts.

  21. Reliability • Grade A products must be certified to have passed 1000 surges of 6000 volts and 3000 amperes without failure. • Grade B products must pass 1000 surges of 4000 volts and 2000 amperes. • Grade C products must pass 1000 surges of 2000 volts and 1000 amperes.

  22. Mode of Suppression • Mode 1 products protect the ground by not diverting surge energy to it. • Mode 2 products contaminate the ground wire.

  23. Price Range Surge suppressors (Class A, Grade 1, Mode 1): • 7.5A: $125 • 15A: $169 • 20A: $249 Surge Diverters (Only Performance Data is available): • Class A: approximately $30 • Class D: approximately $9.99

More Related