Re: [PSES] question with regard of inverter

2014-08-12 Thread McDiarmid, Ralph 
The 800 lb gorilla should learn to read and check the applicable standard. 
 (assuming 62109 was applicable for that equipment)

And, I thought the only 800 lb gorillas were the electric utilities.  ;-))
___ 


Ralph McDiarmid  |   Schneider Electric   |  Solar Business  |   CANADA  | 
  Regulatory Compliance Engineering 



From:
Pete Perkins <0061f3f32d0c-dmarc-requ...@ieee.org>
To:
EMC-PSTC@LISTSERV.IEEE.ORG, 
Date:
08/08/2014 05:47 PM
Subject:
Re: [PSES] question with regard of inverter



Peter,
 
All well and good per IEC 62109 however the 800lb gorilla 
NRTL assessed the PV DC current monitor assembly (a piece of measurment 
equipment) to be OV CAT  IV when it was assessed for certification. 
 
The manufacturer grumbled somewhat (since it wasn't 
designed for that OV category) but agreed that it was probably 
appropriate, as did I.  
 
:>) br, Pete
 
Peter E Perkins, PE
Principal Product Safety Engineer
PO Box 23427
Tigard, ORe  97281-3427
 
503/452-1201 fone/fax
p.perk...@ieee.org
 
From: Peter Tarver [mailto:ptar...@enphaseenergy.com] 
Sent: Friday, August 08, 2014 3:47 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] question with regard of inverter
 
IEC 62109-1 considers “PV circuits in general” to be OVCII.
 
Regards,
 
Peter Tarver
 
From: McDiarmid, Ralph [mailto:ralph.mcdiar...@schneider-electric.com] 
Sent: Friday, August 08, 2014 13:57
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] question with regard of inverter
 
My understanding as well, namely, OV categorization in power distribution 
is based on indirect (near-by) lightning strikes. 

___ 


Ralph McDiarmid  |   Schneider Electric   |  Solar Business  |   CANADA  | 
  Regulatory Compliance Engineering 

From: 
John Woodgate  
To: 
EMC-PSTC@LISTSERV.IEEE.ORG, 
Date: 
08/06/2014 01:53 PM 
Subject: 
Re: [PSES] question with regard of inverter
 




In message <53e28a32.4020...@ieee.org>, dated Wed, 6 Aug 2014, Richard 
Nute  writes:

>.  Your solar cell DC source is not
>subject to load switching, but is subject to a direct lightning 
>strike. 
>Your DC OVC due to load switching is zero, and your OVC due to
>lightning is beyond OVC IV.

Is resistance to a direct lighting strike required of civilian products? 
I though that only 'indirect strike' was to be resisted, and OVC IV was 
based on that.
-- 
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
Quid faciamus nisi sit?
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

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Re: [PSES] question with regard of inverter

2014-08-08 Thread Pete Perkins 
Peter,

 

All well and good per IEC 62109 however the 800lb gorilla NRTL 
assessed the PV DC current monitor assembly (a piece of measurment equipment) 
to be OV CAT  IV when it was assessed for certification. 

 

The manufacturer grumbled somewhat (since it wasn't designed 
for that OV category) but agreed that it was probably appropriate, as did I.  

 

:>) br, Pete

 

Peter E Perkins, PE

Principal Product Safety Engineer

PO Box 23427

Tigard, ORe  97281-3427

 

503/452-1201 fone/fax

p.perk...@ieee.org

 

From: Peter Tarver [mailto:ptar...@enphaseenergy.com] 
Sent: Friday, August 08, 2014 3:47 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] question with regard of inverter

 

IEC 62109-1 considers “PV circuits in general” to be OVCII.

 

Regards,

 

Peter Tarver

 

From: McDiarmid, Ralph [mailto:ralph.mcdiar...@schneider-electric.com] 
Sent: Friday, August 08, 2014 13:57
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] question with regard of inverter

 

My understanding as well, namely, OV categorization in power distribution is 
based on indirect (near-by) lightning strikes. 

___ 

Ralph McDiarmid  |   Schneider Electric   |  Solar Business  |   CANADA  |   
Regulatory Compliance Engineering 


From: 

John Woodgate  


To: 

EMC-PSTC@LISTSERV.IEEE.ORG, 


Date: 

08/06/2014 01:53 PM 


Subject: 

Re: [PSES] question with regard of inverter

 

  _  




In message <53e28a32.4020...@ieee.org>, dated Wed, 6 Aug 2014, Richard 
Nute  writes:

>.  Your solar cell DC source is not
>subject to load switching, but is subject to a direct lightning 
>strike. 
>Your DC OVC due to load switching is zero, and your OVC due to
>lightning is beyond OVC IV.

Is resistance to a direct lighting strike required of civilian products? 
I though that only 'indirect strike' was to be resisted, and OVC IV was 
based on that.
-- 
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
Quid faciamus nisi sit?
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

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Re: [PSES] question with regard of inverter

2014-08-08 Thread Peter Tarver 
IEC 62109-1 considers “PV circuits in general” to be OVCII.



Regards,



Peter Tarver



*From:* McDiarmid, Ralph [mailto:ralph.mcdiar...@schneider-electric.com]
*Sent:* Friday, August 08, 2014 13:57
*To:* EMC-PSTC@LISTSERV.IEEE.ORG
*Subject:* Re: [PSES] question with regard of inverter



My understanding as well, namely, OV categorization in power distribution
is based on indirect (near-by) lightning strikes.

___

*Ralph McDiarmid*  |  * Schneider Electric   |  Solar Business*  |
*CANADA*  |   *Regulatory Compliance Engineering*

From:

John Woodgate 

To:

EMC-PSTC@LISTSERV.IEEE.ORG,

Date:

08/06/2014 01:53 PM

Subject:

Re: [PSES] question with regard of inverter


--




In message <53e28a32.4020...@ieee.org>, dated Wed, 6 Aug 2014, Richard
Nute  writes:

>.  Your solar cell DC source is not
>subject to load switching, but is subject to a direct lightning
>strike.
>Your DC OVC due to load switching is zero, and your OVC due to
>lightning is beyond OVC IV.

Is resistance to a direct lighting strike required of civilian products?
I though that only 'indirect strike' was to be resisted, and OVC IV was
based on that.
-- 
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
Quid faciamus nisi sit?
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

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Re: [PSES] question with regard of inverter

2014-08-08 Thread McDiarmid, Ralph 
My understanding as well, namely, OV categorization in power distribution 
is based on indirect (near-by) lightning strikes.

___ 


Ralph McDiarmid  |   Schneider Electric   |  Solar Business  |   CANADA  | 
  Regulatory Compliance Engineering 



From:
John Woodgate 
To:
EMC-PSTC@LISTSERV.IEEE.ORG, 
Date:
08/06/2014 01:53 PM
Subject:
Re: [PSES] question with regard of inverter



In message <53e28a32.4020...@ieee.org>, dated Wed, 6 Aug 2014, Richard 
Nute  writes:

>.  Your solar cell DC source is not
>subject to load switching, but is subject to a direct lightning 
>strike. 
>Your DC OVC due to load switching is zero, and your OVC due to
>lightning is beyond OVC IV.

Is resistance to a direct lighting strike required of civilian products? 
I though that only 'indirect strike' was to be resisted, and OVC IV was 
based on that.
-- 
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
Quid faciamus nisi sit?
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

-

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Re: [PSES] question with regard of inverter

2014-08-08 Thread Richard Nute 

Dear Boštjan:


I participated in most of the drafting of IEC 62368-1.  Please
feel free to ask questions.  So did Pete Perkins.  I don't know
if others also subscribe to this group.


Best regards,
Rich



On 8/8/2014 7:51 AM, Boštjan Glavič wrote:

Dear Rich, dear Doug

Thank you very much for your professional answer. I really appreciate it. It 
helps me a lot and also to my client.

One more question, is there any expert in this group who has real experience 
with new Hazard Based Standard IEC 62368-1? We are currently working on few 
projects and i think that some requirements are not really clear.

Best regards,
Bostjan

Boštjan Glavič
Vodja laboratorija, Laboratorij za elektroniko
Head of Laboratory, Laboratory of Electronic Engineering

[SIQlogo60px]
www.siq.si

SIQ Ljubljana, Trzaska c. 2, SI-1000 Ljubljana, Slovenia, VAT ID: SI23509678
t +386 (0)1 4778 265, m +386 (0)41 391 
283, f +386 (0)1 4778 444







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Re: [PSES] question with regard of inverter

2014-08-08 Thread Boštjan Glavič 
Doug,

I did, also many other documents like UL technical briefs. I have exact 
technical questions. Maybe I prepare a new email and list some of them.

Best regards,
Bostjan

Boštjan Glavič
Vodja laboratorija, Laboratorij za elektroniko
Head of Laboratory, Laboratory of Electronic Engineering

[SIQlogo60px]
www.siq.si<http://www.siq.si/>

SIQ Ljubljana, Trzaska c. 2, SI-1000 Ljubljana, Slovenia, VAT ID: SI23509678
t +386 (0)1 4778 265, m +386 (0)41 391 
283, f +386 (0)1 4778 
444




On 8. avg. 2014, at 16:59, "Doug Powell" 
mailto:doug...@gmail.com>> wrote:

‎Bostjan,

I would suggest you begin by reviewing this article at the IEC.

http://www.iec.ch/etech/2013/etech_0313/tech-2.htm

Thanks, - doug

Douglas Powell
http://www.linkedin.com/in/dougp01
  Original Message
From: Boštjan Glavič
Sent: Friday, August 8, 2014 8:51 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG<mailto:EMC-PSTC@LISTSERV.IEEE.ORG>
Reply To: Boštjan Glavič
Subject: Re: [PSES] question with regard of inverter

Dear Rich, dear Doug

Thank you very much for your professional answer. I really appreciate it. It 
helps me a lot and also to my client.

One more question, is there any expert in this group who has real experience 
with new Hazard Based Standard IEC 62368-1? We are currently working on few 
projects and i think that some requirements are not really clear.

Best regards,
Bostjan

Boštjan Glavič
Vodja laboratorija, Laboratorij za elektroniko
Head of Laboratory, Laboratory of Electronic Engineering

[SIQlogo60px]
www.siq.si<http://www.siq.si><http://www.siq.si/>

SIQ Ljubljana, Trzaska c. 2, SI-1000 Ljubljana, Slovenia, VAT ID: SI23509678
t +386 (0)1 4778 265, m +386 (0)41 391 
283, f +386 (0)1 4778 
444




On 6. avg. 2014, at 22:04, "Richard Nute" 
mailto:ri...@ieee.org><mailto:ri...@ieee.org>> wrote:


Dear Boštjan:


If the solar cells are hit by lightning, then the DC and inverter
system will likely be destroyed, and the transient will propagate
into the AC system. There is no way to protect against a direct
lightning strike except to use a system of lightning rods, and
they may not provide protection against propagation.

Except for a direct lightning strike, no transients appear on the
DC side, so OVC does not apply.

The 120/240 V AC probably is OVC III, and maybe OVC IV.

Since there is no isolation between the AC and the DC, both
will see the same AC transients. Your DC side should use the
same OVC as the AC side.

In my opinion, UL has not fully studied IEC 60664 which is the
definitive standard for OVC. UL has extended the OVC
requirements to DC without researching the origin and value
of transients on DC mains and instead has simply applied the
AC OVC to DC mains.

According to IEC 60664 and other authorities such as Francois
Martzloff, transients on AC systems come from two sources,
lightning and load switching. Your solar cell DC source is not
subject to load switching, but is subject to a direct lightning strike.
Your DC OVC due to load switching is zero, and your OVC due to
lightning is beyond OVC IV.

Some references:

http://www.metrel.si/dl?d=PDF_dokumentacija/White_papers/Ang/White_paper_Overvoltages_and_high_current_breakdowns.pdf

http://www.denverpels.org/Downloads/Denver_PELS_20090915_Aldous_Insulation_Coordination.pdf


Best regards,
Rich







On 8/6/2014 11:25 AM, Boštjan Glavič wrote:

Dear Rich,

Thank you. DC input comes from solar cells therefore from outside. UL 1741 
states that OVC IV needs to be used and for 120/240V it means 4000V. So what 
transient should I use from DC side?

Why table 8.1 in UL840 also mentions dc input?

Best regards,
Bostjan

Boštjan Glavič
Vodja laboratorija, Laboratorij za elektroniko
Head of Laboratory, Laboratory of Electronic Engineering

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A

Re: [PSES] question with regard of inverter

2014-08-08 Thread Doug Powell 
‎Bostjan,

I would suggest you begin by reviewing this article at the IEC.

http://www.iec.ch/etech/2013/etech_0313/tech-2.htm

Thanks, - doug

Douglas Powell
http://www.linkedin.com/in/dougp01  
  Original Message  
From: Boštjan Glavič
Sent: Friday, August 8, 2014 8:51 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Reply To: Boštjan Glavič
Subject: Re: [PSES] question with regard of inverter

Dear Rich, dear Doug

Thank you very much for your professional answer. I really appreciate it. It 
helps me a lot and also to my client.

One more question, is there any expert in this group who has real experience 
with new Hazard Based Standard IEC 62368-1? We are currently working on few 
projects and i think that some requirements are not really clear.

Best regards,
Bostjan

Boštjan Glavič
Vodja laboratorija, Laboratorij za elektroniko
Head of Laboratory, Laboratory of Electronic Engineering

[SIQlogo60px]
www.siq.si<http://www.siq.si/>

SIQ Ljubljana, Trzaska c. 2, SI-1000 Ljubljana, Slovenia, VAT ID: SI23509678
t +386 (0)1 4778 265, m +386 (0)41 391 
283, f +386 (0)1 4778 
444




On 6. avg. 2014, at 22:04, "Richard Nute" 
mailto:ri...@ieee.org>> wrote:


Dear Boštjan:


If the solar cells are hit by lightning, then the DC and inverter
system will likely be destroyed, and the transient will propagate
into the AC system. There is no way to protect against a direct
lightning strike except to use a system of lightning rods, and
they may not provide protection against propagation.

Except for a direct lightning strike, no transients appear on the
DC side, so OVC does not apply.

The 120/240 V AC probably is OVC III, and maybe OVC IV.

Since there is no isolation between the AC and the DC, both
will see the same AC transients. Your DC side should use the
same OVC as the AC side.

In my opinion, UL has not fully studied IEC 60664 which is the
definitive standard for OVC. UL has extended the OVC
requirements to DC without researching the origin and value
of transients on DC mains and instead has simply applied the
AC OVC to DC mains.

According to IEC 60664 and other authorities such as Francois
Martzloff, transients on AC systems come from two sources,
lightning and load switching. Your solar cell DC source is not
subject to load switching, but is subject to a direct lightning strike.
Your DC OVC due to load switching is zero, and your OVC due to
lightning is beyond OVC IV.

Some references:

http://www.metrel.si/dl?d=PDF_dokumentacija/White_papers/Ang/White_paper_Overvoltages_and_high_current_breakdowns.pdf

http://www.denverpels.org/Downloads/Denver_PELS_20090915_Aldous_Insulation_Coordination.pdf


Best regards,
Rich







On 8/6/2014 11:25 AM, Boštjan Glavič wrote:

Dear Rich,

Thank you. DC input comes from solar cells therefore from outside. UL 1741 
states that OVC IV needs to be used and for 120/240V it means 4000V. So what 
transient should I use from DC side?

Why table 8.1 in UL840 also mentions dc input?

Best regards,
Bostjan

Boštjan Glavič
Vodja laboratorija, Laboratorij za elektroniko
Head of Laboratory, Laboratory of Electronic Engineering

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Re: [PSES] question with regard of inverter

2014-08-08 Thread Boštjan Glavič 
Dear Rich, dear Doug

Thank you very much for your professional answer. I really appreciate it. It 
helps me a lot and also to my client.

One more question, is there any expert in this group who has real experience 
with new Hazard Based Standard IEC 62368-1? We are currently working on few 
projects and i think that some requirements are not really clear.

Best regards,
Bostjan

Boštjan Glavič
Vodja laboratorija, Laboratorij za elektroniko
Head of Laboratory, Laboratory of Electronic Engineering

[SIQlogo60px]
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283, f +386 (0)1 4778 
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On 6. avg. 2014, at 22:04, "Richard Nute" 
mailto:ri...@ieee.org>> wrote:


Dear Boštjan:


If the solar cells are hit by lightning, then the DC and inverter
system will likely be destroyed, and the transient will propagate
into the AC system.  There is no way to protect against a direct
lightning strike except to use a system of lightning rods, and
they may not provide protection against propagation.

Except for a direct lightning strike, no transients appear on the
DC side, so OVC does not apply.

The 120/240 V AC probably is OVC III, and maybe OVC IV.

Since there is no isolation between the AC and the DC, both
will see the  same AC transients.  Your DC side should use the
same OVC as the AC side.

In my opinion, UL has not fully studied IEC 60664 which is the
definitive standard for OVC.  UL has extended the OVC
requirements to DC without researching the origin and value
of transients on DC mains and instead has simply applied the
AC OVC to DC mains.

According to IEC 60664 and other authorities such as Francois
Martzloff, transients on AC systems come from two sources,
lightning and load switching.  Your solar cell DC source is not
subject to load switching, but is subject to a direct lightning strike.
Your DC OVC due to load switching is zero, and your OVC due to
lightning is beyond OVC IV.

Some references:

http://www.metrel.si/dl?d=PDF_dokumentacija/White_papers/Ang/White_paper_Overvoltages_and_high_current_breakdowns.pdf

http://www.denverpels.org/Downloads/Denver_PELS_20090915_Aldous_Insulation_Coordination.pdf


Best regards,
Rich







On 8/6/2014 11:25 AM, Boštjan Glavič wrote:

Dear Rich,

Thank you. DC input comes from solar cells therefore from outside. UL 1741 
states that OVC IV needs to be used and for 120/240V it means 4000V. So what 
transient should I use from DC side?

Why table 8.1 in UL840 also mentions dc input?

Best regards,
Bostjan

Boštjan Glavič
Vodja laboratorija, Laboratorij za elektroniko
Head of Laboratory, Laboratory of Electronic Engineering

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Re: [PSES] question with regard of inverter

2014-08-06 Thread John Woodgate 
In message <53e28a32.4020...@ieee.org>, dated Wed, 6 Aug 2014, Richard 
Nute  writes:



.  Your solar cell DC source is not
subject to load switching, but is subject to a direct lightning 
strike. 

Your DC OVC due to load switching is zero, and your OVC due to
lightning is beyond OVC IV.


Is resistance to a direct lighting strike required of civilian products? 
I though that only 'indirect strike' was to be resisted, and OVC IV was 
based on that.

--
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
Quid faciamus nisi sit?
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

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Re: [PSES] question with regard of inverter

2014-08-06 Thread Richard Nute 


Dear Boštjan:


If the solar cells are hit by lightning, then the DC and inverter
system will likely be destroyed, and the transient will propagate
into the AC system.  There is no way to protect against a direct
lightning strike except to use a system of lightning rods, and
they may not provide protection against propagation.

Except for a direct lightning strike, no transients appear on the
DC side, so OVC does not apply.

The 120/240 V AC probably is OVC III, and maybe OVC IV.

Since there is no isolation between the AC and the DC, both
will see the  same AC transients.  Your DC side should use the
same OVC as the AC side.

In my opinion, UL has not fully studied IEC 60664 which is the
definitive standard for OVC.  UL has extended the OVC
requirements to DC without researching the origin and value
of transients on DC mains and instead has simply applied the
AC OVC to DC mains.

According to IEC 60664 and other authorities such as Francois
Martzloff, transients on AC systems come from two sources,
lightning and load switching.  Your solar cell DC source is not
subject to load switching, but is subject to a direct lightning strike.
Your DC OVC due to load switching is zero, and your OVC due to
lightning is beyond OVC IV.

Some references:

http://www.metrel.si/dl?d=PDF_dokumentacija/White_papers/Ang/White_paper_Overvoltages_and_high_current_breakdowns.pdf

http://www.denverpels.org/Downloads/Denver_PELS_20090915_Aldous_Insulation_Coordination.pdf


Best regards,
Rich







On 8/6/2014 11:25 AM, Boštjan Glavič wrote:

Dear Rich,

Thank you. DC input comes from solar cells therefore from outside. UL 1741 
states that OVC IV needs to be used and for 120/240V it means 4000V. So what 
transient should I use from DC side?

Why table 8.1 in UL840 also mentions dc input?

Best regards,
Bostjan

Boštjan Glavič
Vodja laboratorija, Laboratorij za elektroniko
Head of Laboratory, Laboratory of Electronic Engineering



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Re: [PSES] question with regard of inverter

2014-08-06 Thread Doug Powell 
Bostjan,

Even though PV array can be subject to lightning strikes, to my knowledge
there is no specific requirement for OV transients occurring on the DC side
of your inverter.  This leaves you in a bit of a quandary fro spacings
determination on the DC side, especially if you have no transformer
isolation.

Although your power production is from DC to AC, your system is still
subjected to OV transients originating from the AC side mains connections.
 These connections will indeed be category IV if you are connected to the
LV side of an MV transformer.  For the DC side, I would use the Controlled
Overvoltage requirements in of UL 840 for the DC side (see Clause
8.7).  Depending
on the design of your product and the likelihood of AC side transients
propagating through to the
DC side, you may be able to reduce the OV Cat by one full step or more on
the DC side.  This can be achieved in a few
ways, transformer isolation being the most obvious.  However,
the standard does allow attenuation by impedance networks.  In this case
the impedance network is comprised of your AC EMI filter, AC line reactors,
and DC bus cap.  Approved transient suppression devices can also be useful.

If you believe your system is able to absorb or suppress these transients
to a level below Cat IV by virtue of the impedance network, you can prove
this is true through test by applying OV Cat IV impulses the mains and
monitoring the circuit in question using an oscope (UL 840 section 12.1).
 In this case use the 1.25/50 uS impulse test.  Be certain
your application of the impulses and the connection of you oscope is in
all orientations of line to line and line to earth, in order to see
the maximum impulses available on the DC side.  Your results should not
exceed OV Cat III, for example.

Good luck, –doug

Douglas E Powell
http://www.linkedin.com/in/dougp01


On Wed, Aug 6, 2014 at 12:25 PM, Boštjan Glavič 
wrote:

> Dear Rich,
>
> Thank you. DC input comes from solar cells therefore from outside. UL 1741
> states that OVC IV needs to be used and for 120/240V it means 4000V. So
> what transient should I use from DC side?
>
> Why table 8.1 in UL840 also mentions dc input?
>
> Best regards,
> Bostjan
>
> Boštjan Glavič
> Vodja laboratorija, Laboratorij za elektroniko
> Head of Laboratory, Laboratory of Electronic Engineering
>
> [SIQlogo60px]
> www.siq.si
>
> SIQ Ljubljana, Trzaska c. 2, SI-1000 Ljubljana, Slovenia, VAT ID:
> SI23509678
> t +386 (0)1 4778 265, m +386 (0)41 391 
> 283,
> f +386 (0)1 4778 444
>
>
>
>
> On 6. avg. 2014, at 20:17, "Richard Nute"  ri...@ieee.org>> wrote:
>
>
>
> Dear Boštjan:
>
>
> Despite UL1741 and UL 840, OVC does not apply to DC.  There is
> no research that I know of that supports use of AC OVC to DC.
>
> If the 450 V DC is not outside the building or is otherwise not
> subject to lightning-caused overvoltages, OVC does not apply.
>
> Likewise, if the 450 V DC only supplies a limited number of other
> loads (which are assumed to generate transients when switched
> on or off), OVC does not apply.
>
> Since there is no isolation from input to output, whatever insulation
> between input and output is "functional" insulation.   The transients
> that appear on the AC output side (generated by load switching and
> lightning) will also appear on the DC side.
>
> 120\240 V overvoltages are OVC II and are 3 kV according to
> IEC 60664, not 4 kV.
>
>
> Best regards,
> Rich
>
>
> On 8/6/2014 10:39 AM, Boštjan Glavič wrote:
> Dear experts,
>
> I am trying to figure out how to determine correct spacings for
> non-isolated inverter. According UL1741 OVC IV needs to be considered for
> inverter. From table 8.1 from UL840 I get a transients of 8,0kV for 450VDC
> input. Is that correct?
>
> Output of inverter is connected to AC grid 120/240V. This results in 4kV
> transients.
>
> We have no insulation input/output. Which transient level should I then
> use? 8kV transient on AC output side is almost impossible for the design.
>
> Any idea?
>
> Best regards,
> Bostjan Glavic
> SIQ
> -
> 
>
> This message is from the IEEE Product Safety Engineering Society emc-pstc
> discussion list. To post a message to the list, send your e-mail to <
> emc-p...@ieee.org>
>
> All emc-pstc postings are archived and searchable on the web at:
> http://www.ieee-pses.org/emc-pstc.html
>
> Attachments are not permitted but the IEEE PSES Online Communities site at
> http://product-compliance.oc.ieee.org/ can be used for graphics (in
> well-used formats), large files, etc.
>
> Website: http://www.ieee-pses.org/
> Instructions: http://www.ieee-pses.org/list.html (including how to
> unsubscribe)
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> Mike Cantwell mailto:mcantw...@ieee.org>>
>
> For policy q

Re: [PSES] question with regard of inverter

2014-08-06 Thread Boštjan Glavič 
Dear Rich,

Thank you. DC input comes from solar cells therefore from outside. UL 1741 
states that OVC IV needs to be used and for 120/240V it means 4000V. So what 
transient should I use from DC side?

Why table 8.1 in UL840 also mentions dc input?

Best regards,
Bostjan

Boštjan Glavič
Vodja laboratorija, Laboratorij za elektroniko
Head of Laboratory, Laboratory of Electronic Engineering

[SIQlogo60px]
www.siq.si

SIQ Ljubljana, Trzaska c. 2, SI-1000 Ljubljana, Slovenia, VAT ID: SI23509678
t +386 (0)1 4778 265, m +386 (0)41 391 
283, f +386 (0)1 4778 
444




On 6. avg. 2014, at 20:17, "Richard Nute" 
mailto:ri...@ieee.org>> wrote:



Dear Boštjan:


Despite UL1741 and UL 840, OVC does not apply to DC.  There is
no research that I know of that supports use of AC OVC to DC.

If the 450 V DC is not outside the building or is otherwise not
subject to lightning-caused overvoltages, OVC does not apply.

Likewise, if the 450 V DC only supplies a limited number of other
loads (which are assumed to generate transients when switched
on or off), OVC does not apply.

Since there is no isolation from input to output, whatever insulation
between input and output is "functional" insulation.   The transients
that appear on the AC output side (generated by load switching and
lightning) will also appear on the DC side.

120\240 V overvoltages are OVC II and are 3 kV according to
IEC 60664, not 4 kV.


Best regards,
Rich


On 8/6/2014 10:39 AM, Boštjan Glavič wrote:
Dear experts,

I am trying to figure out how to determine correct spacings for non-isolated 
inverter. According UL1741 OVC IV needs to be considered for inverter. From 
table 8.1 from UL840 I get a transients of 8,0kV for 450VDC input. Is that 
correct?

Output of inverter is connected to AC grid 120/240V. This results in 4kV 
transients.

We have no insulation input/output. Which transient level should I then use? 
8kV transient on AC output side is almost impossible for the design.

Any idea?

Best regards,
Bostjan Glavic
SIQ
-


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Re: [PSES] question with regard of inverter

2014-08-06 Thread Richard Nute 



Dear Boštjan:


Despite UL1741 and UL 840, OVC does not apply to DC.  There is
no research that I know of that supports use of AC OVC to DC.

If the 450 V DC is not outside the building or is otherwise not
subject to lightning-caused overvoltages, OVC does not apply.

Likewise, if the 450 V DC only supplies a limited number of other
loads (which are assumed to generate transients when switched
on or off), OVC does not apply.

Since there is no isolation from input to output, whatever insulation
between input and output is "functional" insulation.   The transients
that appear on the AC output side (generated by load switching and
lightning) will also appear on the DC side.

120\240 V overvoltages are OVC II and are 3 kV according to
IEC 60664, not 4 kV.


Best regards,
Rich


On 8/6/2014 10:39 AM, Boštjan Glavič wrote:


Dear experts,

I am trying to figure out how to determine correct spacings for 
non-isolated inverter. According UL1741 OVC IV needs to be considered 
for inverter. From table 8.1 from UL840 I get a transients of 8,0kV 
for 450VDC input. Is that correct?


Output of inverter is connected to AC grid 120/240V. This results in 
4kV transients.


We have no insulation input/output. Which transient level should I 
then use? 8kV transient on AC output side is almost impossible for the 
design.


Any idea?

Best regards,

Bostjan Glavic

SIQ

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[PSES] question with regard of inverter

2014-08-06 Thread Boštjan Glavič 
Dear experts,

I am trying to figure out how to determine correct spacings for non-isolated 
inverter. According UL1741 OVC IV needs to be considered for inverter. From 
table 8.1 from UL840 I get a transients of 8,0kV for 450VDC input. Is that 
correct?

Output of inverter is connected to AC grid 120/240V. This results in 4kV 
transients.

We have no insulation input/output. Which transient level should I then use? 
8kV transient on AC output side is almost impossible for the design.

Any idea?

Best regards,
Bostjan Glavic
SIQ

-

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discussion list. To post a message to the list, send your e-mail to 


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