 | |||||
|
|
|||||
|
 |
Wednesday, October 26 PQS 07 Clearing the IEC TN-C-S and the L-N-G Alphabet Soups for SPD Protection Modes and TOV Effects on Surge-Protective Devices 8:30 am-9:00 am Clearing the IEC TN-C-S and the L-N-G Alphabet Soups for SPD Protection Modes Some confusion still exists on the need to provide surge protection components between all possible conductor combinations (lines, neutral, and ground) at the service entrance of three-phase power systems. The confusion is compounded by the variety of neutral grounding configurations that can be found in North America and even more in world-wide situations. While conservative approaches might consist in providing, indeed, an SPD component between all possible pairs of conductors, resulting in the so-called† 10-mode protection? a careful review of the occurrence and propagation of surges in TN systems leads to a more cost-effective protection scheme with only 7, or even 6 modes of protection that will ensure complete surge protection of the loads. Co-author: Dalibor Kladar, EATON ELECTRICAL, (Calgary, Alberta) 9:00am - 9:30am TOV Effects on Surge-Protective Devices Among the diverse equipment permanently installed or plug-connected in low-voltage power distribution systems, SPDs have a special position because of the expectation that they perform an effective protective function against surges. However (and unfortunately), because of the common misuse of the word “surge,” in spite of a specific IEEE definition, some expectations linger that an SPD might also protect equipment against temporary overvoltages (TOVs). The reality is that because of their intended deliberate response to any overvoltage, SPDs (if not properly designed or correctly used) are perhaps more likely to be victims rather than protectors in a TOV scenario. This paper reports TOV susceptibility tests on SPDs, which can provide motivation for standards-developing groups as well as users toward careful assessment of SPD TOV sensitivity. Co-authors: Dalibor Kladar, EATON ELECTRICAL, (Calgary Alberta) and Doni Nastasi. EPRI Solutions, (Knoxville, Tennessee)
|
|
|
|||||||||||||
|
|
|
|
|
