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11:03 am
2009/03/02
Offline
Quoteafter 15 years of experience I feel important to come back to some basics
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
11:04 am
i am studying short circuit calculation for power systems.pls send me the data for designing and selection of protective devices for sc
11:36 am
Hello,
Could you be little more specific because Lightning protection is a large field .
11:40 am
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 ! ! !
11:51 am
Lighting arrester is a infinite source of electrone and proton so It is the better path of protecting of electrical and electronic equipment.
1:15 pm
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-installa…..rges_in_LV
7:33 am
SEREYBOTH said:
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 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.lightningsafety.com…..htning.pdf
Best regards
6:08 pm
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.
8:29 am
Hello,
I just read the Electrical Installation Guide ,chapter J :Protection against voltage surges in LV , so i can uderstand about lightning & surge protection better than before.
thanks Mr Mignardot that provided me a home page.
best regard
BOTH;cambodia
sereybothmay@yahoo.com
8:31 am
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.
8:31 am
2010/04/26
Offline
We appreciate your presence on our blog, what we hope is that you will take benefit of your experience on the Lightning proctection subject to add valuable comment to the proposed topic. Direct promotion without added-value to our community will be taken out.
Blog moderator team
8:31 am
(this comment has been edited by moderator team)
Our society XXXXXXXX is one of the professional companies specialize in the prevention of lightning damaging effects at Vietnam and neighbor countries. We are a leader in Distribution, Installation, Maintenance, Consultancy and Designing services, supervision of installation of system, measuring of lightning protection, grounding systems and transient voltage surge suppression technology.
8:31 am
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
8:31 am
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
8:31 am
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.
8:31 am
Our company manufactured surge protector. any question you can direct to my email
XXXXXXXX
(this comment has been edited by moderator team)
Note: Direct Publicity without added value will be deleted. – Moderator Team
8:31 am
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
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