Surge Protection Devices

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greggs007

Member
Location
India
Hi,

I have a client with 8 Level commercial building. There are 04 utility transformers 11kV/415V 3 Ph (01 for two levels) and 04 Main Feeder Panels (01 for two levels) located at the ground level. Each level above has one Main Power Panel feeding sub-distribution panels within the same level. The sub-distribution panels are UPS Power Panel, AC Panel, Power Panel, Lighting Panel etc. The next level of distribution are DBs for various loads.

The panel load ratings are (a) Main Feeder Panels at Ground Level: 1000A-1600A (b) Main Power panel at each Level: 630A - 1600A (c) Sub-distribution Panel: 800A - 250A (d) DBs <100A

Can someone guide me for ratings for the surge protection devices that I should look for in order to protect all essential and critical loads. What products would meet my requirement

The lightening exposure in the area is medium and the voltages are 230/400.

Thanks
 

cadpoint

Senior Member
Location
Durham, NC
... Surge Arresters Surge arresters are furnished only when listed in the user's
specifications. When specified, surge arresters are ...



From the manufacture Square D

Welcome to the Forum!
 
Hi,

I have a client with 8 Level commercial building. There are 04 utility transformers 11kV/415V 3 Ph (01 for two levels) and 04 Main Feeder Panels (01 for two levels) located at the ground level. Each level above has one Main Power Panel feeding sub-distribution panels within the same level. The sub-distribution panels are UPS Power Panel, AC Panel, Power Panel, Lighting Panel etc. The next level of distribution are DBs for various loads.

The panel load ratings are (a) Main Feeder Panels at Ground Level: 1000A-1600A (b) Main Power panel at each Level: 630A - 1600A (c) Sub-distribution Panel: 800A - 250A (d) DBs <100A

Can someone guide me for ratings for the surge protection devices that I should look for in order to protect all essential and critical loads. What products would meet my requirement

The lightening exposure in the area is medium and the voltages are 230/400.

Thanks

The IEEE Defined Zones or levels of surge protection gives a layered approach and defines protective levels of A, B and C. http://literature.rockwellautomation.com/idc/groups/literature/documents/wp/4983-wp001_-en-d.pdf is a start.
 

PitTip

New member
RE: Sizing surge protectors

RE: Sizing surge protectors

greggs007,

You may want to check out two suppliers. APT and Siemens offer surge protection design guides that will assist in identifying the locations on the electrical system where surge protective devices should be installed. Secondly, they provide recommended part number for the different installation locations.

Since facility electrical system surge current exposure is limited due to flashover of clearances, surge protector sizing is dependent upon not only surge current exposure but to safety and protection practices. For example, we found over time that surge protectors require fault current coordination from near 0 to 200kA. In order to achieve coordination, we found that SPD needed to be comprised of surge protection elements (typically MOVs) with a certain mass (32mm or larger). During fault conditions, these larger elements, hang in long enough without rupturing so fault current safety controls to kick in. The side benefit of such practice of using large MOVs is the surge protection robustness they afford. MOVs used within APT and Siemens SPDs have a surge current capacity of 50kA each. These components are then configured within our hardwired SPDs to protect against surges propagating between electrical system?s paired conductors.

Voltage surge pulses propagate electrical systems via the systems paired conductors ? phase to neutral (L-N), phase to ground (L-G), neutral to ground (N-G), and phase to phase (L-L). Typical entry level SPDs, provide surge protection for the electrical systems current carrying conductors (L-N). To keep cost down, these units connect a 50kA MOV across these conductors. Some designers prefer to surge protect their system with SPDs providing protection for L-G and N-G. The reasoning behind upgrading is the idea that we just can?t be assured that electrical surges will always propagate between L-N. Thus, designers prefer to specify SPDs that offer others modes of protection protecting against surges propagating via L-G and N-G, while indirectly or directly protecting L-L. For a standard split phase or wye configured SPD providing one MOV connected across L-N, L-G, and N-G will have a per phase surge current capacity of 100kA. Some designers take this base configuration extend it further preferring to specify SPDs offering increased redundancy and robustness via multiple paralleled MOVs increasing SPD surge current ratings from 100kA to 150, 200, 250, 300, etc.. kA.

Using 25 plus years of data from North American consulting engineer specification practices, APT and Siemens developed surge protection design guides. These guides use representative structures/facilities recommending SPD electrical system installation locations as well as SPD surge current capacity.
 

tom baker

First Chief Moderator
Staff member
Start with Article 285.
Its very simple
"you get what you pay for.
More is better."
(Mike Holt)
SPD on the service.
SPD on each feeder panel
SPDs at point of use.
Use the service and feeder SPDs to knock down the surge, use the building wiring impedance to reduce it more, to where the point of use SPD is effective.
 
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