after 15 years of experience I feel important to come back to some basics
city lightning
Protection against the destructive lightning effects should be considered globally.
To avoid the fire of a building we will use the “external” lightning protection system such as lightning conductor or meshed cage.
In the same way, we will install Surge Arrester or surge protector (also called SPD, Surge Protective Device) in the Electrical main board to protect sensitive electrical equipment against surges generated by lightning strokes fell close or directly on the building.
15 years of experience in the field of surge protection lead me to write that the technology and understanding of phenomena has evolved. However, further issues have to be clarified …
One of the main issues to clarify in my opinion is the behaviour of the surge arrester, “surge protector“ (SPD) implemented in an electrical panel. Today many designers think it is enough to connect a surge protector (SPD) on the grid so that it provides protection against surges caused by lightning effects. Of course, this role is the main function of the surge protector (SPD). Nevertheless we have to consider its integrity in operation, outside a period of storm, mainly during the permanent fault on the electrical power network.
In other words, a surge protector (SPD) must be coordinated with a safety protective device that disconnects from the network when the SPD is in short circuit. The cause of this development are mainly short-circuit failure of the neutral or permanent overvoltage which unfortunately appear on the electrical networks (from current or renewable energy)
Surge protection can be effective and safe if this association is coordinated with its protective device (Circuit breaker or fuse). For example, surge protector (SPD) with nominal current discharge In=5kA should be associated with a circuit breaker C curve – 20A, breaking capacity consistent with Isc of the electrical installation from (6KA to 25kA)
by the way, you can visit this site : Interesting web site dealing with the lightning phenomena in the several fields as meteorology, medical, scientific and technical – in French and English languages
Didier Mignardot
Join the forum discussion on this post
I’m from Mongolia. I’m not good at English. Now I am working and studying power engineering (high voltage earthing research) is there any one who share with your skills. if so thank you very much.
Hello,
Could you be little more specific because Lightning protection is a large field .
Hello,
I am cambodia.I am not well in writing English,working at Siem Reap diesel power plant(10MW).Now my country has many lightnings during raining that kills people, damages eletrical overhead transmission line(22kv) and low voltage electric devices.
could you help me, how protection,how to get a good skill in surge protection ! ! !
Hello,
I suggest to have a look on standardization guide . This is the IEC 61643-21 or the Electrical Installation Guide chapter J dedicated to Surge arrester:
http://www.electrical-installation.schneider-electric.com/ei-guide/j-protection-voltage-surges.htm
Hello,
rotection against voltage surges in LV , so i can uderstand about lightning & surge protection better than before.
I just read the Electrical Installation Guide ,chapter J
thanks Mr Mignardot that provided me a home page.
best regard
BOTH;cambodia
sereybothmay@yahoo.com
I suggest you could also download the document “Cahier Technique n°151″, which deals with overvoltages and insulation coordination for MV and could complement what you found in the LV guide, from the Schneider-Electric web site at the following address:
http://www.schneider-electric.com/documents/technical-publications/en/shared/electrical-engineering/electrical-know-how/high-voltage-plus-1kv/ect151.pdf
Have a good reading,
Our company manufactured surge protector. any question you can direct to my email itachidungga@yahoo.com.my
i want to know the Contruction and Functioning principle of MOV,GDT.
Let me know about your works to enable us to proposed our products
Lighting arrester is a infinite source of electrone and proton so It is the better path of protecting of electrical and electronic equipment.
The information you include about SPD´s iwill mislead the opinion of
engineers
because there´re manufacturers that had consider the problem and
include a fuse in front
of each MOV, designed to open the circuit in case of a failure or end of life of the varistor.
but it´s not any fuse, because it goes in the protection module in front of each MOV. On the other hand a limiting fuse for protection will jeopardize the function of the SPD
This is a very interesting comment because you give me the opportunity to clarify the end of life mode of SPD (including MOVs and gas tube):
Let me explain two cases.
A surge arrester can happen at the end of life in the following cases:
a) by thermal runaway due to an accumulation of excessive constraints of not exceeding its lightning
attributes, leading to a slow destruction of its internal components.
The disconnection of the SPD is provided by a thermal fuse associated with the electronic components (MOVs) inside the SPD
b) by short-circuit due to exceeding the maximum flow capacity or due to a fault under 50hz from the electrical distribution network (neutral rupture ,…). The disconnection of the SPD is provided by an external or integrated short circuit protection device like fuse or circuit breaker.
Considering the short circuit protection device(b), why choose circuit breaker instead of fuse?
● Choose the rating must consider both surge withstand and low short circuit breaking capability
● Compare to fuses, CBs have good compromise between surge withstand and low short circuit breaking capability
*The same rating CB has better surge withstand capability than fuse
*The lower rating CB has better short circuit breaking capability
For instance, SPD with following characteristics : In=5kA, Up=1,3kV is coordinated with its short circuit protection device:
* circuit breaker C curve 20A
* or fuse 22×58 63A
Fuse only functioned in steady state condition.But lightning & surge happened in transient condition.The different is times d/dt .
Some other manufacture use the fuse is to protect the current and temperature.for normal supply current is below than 2-3A.That why manufacturer will used fuse rating 10-15A.Depend on rating MOV’s.
Thanks for this post
i am studying short circuit calculation for power systems.pls send me the data for designing and selection of protective devices for sc
As you can see below, coordination between SPD and MCB(F2 in the text) is given by the manufacturer’SPD instructions
extract from IEC 60364-5-534:
“534.2.4 Protection against overcurrent and consequences of an SPD failure
Protection against SPD’s short-circuits is provided by the overcurrent protective devices F2
(see figures in the annexes A to D) which are to be selected according to the maximum
recommended rating for the overcurrent protective device given in the manufacturer’s SPD
instructions.”
moreover the product standard IEC 61643-11 refers to disconnector (overcurrent protective devices) as you can show below:
extract from IEC 61643-11/2005:
” 6.2.7 SPD disconnector
The SPD may have SPD disconnectors (which can be either internal, external or both). Their
operation shall be indicated.
NOTE Installation requirements not related to the SPDs may require additional and/or lower rated overcurrent protective devices.
SPD disconnectors shall be tested with the SPD during the sequence of type tests of 7.7 and
7.8.3, except for RCDs, which are not tested during the operating duty test according to
7.7.1.”
My advice is to contact manuifacturer’s SPDs and ask to them this coordination table
Please refer to Epcos website and download form there
my commumity power suplly suffers from low voltage between the hours of 6 and 9 when all electrical equipment(electric cookers,a/c ) are switced on .new buildings have sprang up all dependig on the same supply.please,
what are the effect of the low voltage on electrical appliances,
what are some other couses of the low voltage,
what are the possible solutions.
thanks
Whoa, gotta love that picture of the lightning. Must have been a super high-end camera with superb timing to capture a shot like that. Any idea of what city that is of?
-Jack
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i am lecturer in engg. college , pls send data in detail
Hello, I am Ratha.
I would very much appreciate if the group could share with me the information of Installation of Earthing (Grounding) for Direct Lightning Protection system. And the installation of Down Conductor.
Thank you very much.
Iwould say you have to install a 3 phase protector at the service entrance to avoid this problem.
I would like to ask if someone have made measurements of the shape of the wave at the service entrance in any distribution system of any electrical utility co.in any city or country.
I´m curious to learn if a SPD should include EMI/RFI noise filtering or if a SINE WAVE TRACKING WILL BE ENOUGH in order to supply a clean signal to the utility customers.
thanks for your help,
GERARDO TAMA
You can protekt with ”PREVECTRON” INDELEC France.I put this from 5 years on the buildings.
hi
could you help me for finding INDELECT software for finding the best place for installing prevectron?
SEREYBOTH said:
Hello,
I am from Malaysia which has more lightning than Cambodia. I have written some articles on direct strike lightning protection which may help you:
http://www.lightningsafetyalli…..minals.pdf
http://www.lightningsafety.com…..ission.pdf
http://www.lightningsafety.com…..1_2007.pdf
http://akihito-shigeno.com/fil…..008_1_.pdf
http://www.mikeholt.com/newsle…..tterID=823
http://www.lightningsafety.com…..htning.pdf
Best regards
SEREYBOTH said:
Dear Cambodia,
I,m dinesh kumar represting an XXXXXXX, we here provide Power Quality solutions to such a type of poor line i.e. surge solution.
kindly send your problem in detail with Electrical Pannel size.
We will surely provide u solution within time frame.
rgds
Dinesh
XXXXXXXXXXX
(This comment is edited by moderator team)
(Please note that any publicity without added value is deleted. Thank You!)
Excellent topic. I jus want to add something that I guess is important, maybe you already talked about. It is very important to have a good grounding system , otherwise the SPD is not going to do its work properly, and for those star systems it is important to make a reference at the entrance of the system (Neutral to earht conection) in order to minimaze the transients.
Hello, tree-phase protection at the building entrance (using heavy discharge tubes made by TTI Puerto Rico) has solved most problems in Venezuela. However there is a ever growing problem present, probably world-wide. The problem is as follows:
Most computer users buy “stabilyzers” using MOV type surge protectors. These are single-phase devices and see what the happens doring a lighning storm: when surge arrives, the sinle phase MOV will cut the overvoltage surge to a save level for the computer it is ment to protect. But now the catastrophic effect is because the power clippling at one phase rises very dangerously spikes at athe other two phases at the whole building. I have seen a chane of PC failures that did not have MOV protection.
This effect should be communidated to all computer-users !
The real solution is really a building-entrance protection, while the individual MOV protection at the consumer load is too danderous !
Please comment your experience ! Rehards Hans Stauffer, Caracas Venezuela (stauffer@cantv.net)
Ratha said:
you can send e-mail to sales03@fatech-surge-protection.com, they are professional on provide lightning and surge protection proposal, and grounding proposal.
Hi
Isn't the surge protective philosophie concerning T2 arresters described in Wiki-EIG a little bit old -fashioned?
http://www.electrical-installa…..Type_2_SPD
I understand that it is coming from the time when France had own standard which knew only todays T2 arresters and they were suggested to be choosen concerning by risk of lightning (and by more valuable equipment).
Today, when international standard uses 'german' (my term) approach - T1, T2, T3 arresters – I do not see the reason to split T2 arresters (which are mainly varistors) into so many different levels. The Up of smaller varistors is mainly lower only for the reason that Up is always measured by In, so by the same surge current the actual Ures is the same , or by same cases – more powerful arresters have even lower Ures thah the smaller ones.
There is not significant price difference either (at least on our market) between T2 arresters having Imax 40, 20, 15 , or 5 kA.
T2 arresters having Imax 65 kA are today sold under label T1+2 with Iimp =7kA
Price depends more from how famous is the brand name of the producer or of his activity on the market.
I find that there is enough to have one standard T2 arrester 40/20kA and in the last end to use T3 arrester.
Btw. If I read the definition of the “Lighting Protection Zones” in EN 62 305 , than I understand, that LPZ 3 requires defenitely screening of the zone. So – it means that there is no sense to install T3 arrester into distribution board if the device to be protected is located not in the same DB but situated somewhere in distance and feeded via normal PVC cable without screen?
(of course – installation T3 there makes not the situation worse)
PS
What You as specialists think about so called 'T1+2' arresters, which itself are only a little bit more powerful varistors.
Is their effect really comparable with devices where 2 physically different devices (spark gap and varistor) are mounted beside each other (sometimes on the same base only, sometimes into the same housing)?
Francois said:
Lightning & Surge protection is the very sensetive equipment to save the auxilaries from lighting strokes