What frequency of DC current has to be detectable in EV charge points?

[Flyback]

Hi,
EV charge points need to detect DC of magnitude 6mA to 300mA.
Though at what frequency must they detect this over?

Also, what test equipment can assure this?

Do you know for instance, what frequencies the metrel tester does the dc leakage test at?

Basically the standards that discuss this are IEC61851-1:2017 and IEC62752. (but we are a start up and cant afford standards)

 

[Pommie]

How can DC have a frequency?

Mike.

 

[Flyback]

if you like on type B RCD datasheets, you see there the frequency associated with the frequency.
But your question is excellent, and i also wonder how the pulsing DC of frequencies up to 200khz can appear in the AC mains.

 

[Pommie]

But your question is excellent

But you didn't answer it anyway!!!
Repeat,
How can DC have a frequency?

Mike.
And, BTW, I always expect frequency to be associated with frequencies.

 

[Flyback]

How can DC have a frequency?

You mean how can DC leakage currents in the mains have a frequency?

...I guess because the equipment connected to the mains has DC in it, and has some kind of pulsing operation, eg like an SMPS or drive.

Why DC leakage currents need to be protected against with type B rcds in some equipment, but only type A is needed in other equipment, is anyone's guess.....no website clears this up.

 

[Nigel Goodwin]

You mean how can DC leakage currents in the mains have a frequency?

...I guess because the equipment connected to the mains has DC in it, and has some kind of pulsing operation, eg like an SMPS or drive.

Which is AC - NOT DC - as has been said, you can't have a frequency with DC.

 

[JimB]

I believe that the intrepid Flyback means "Sample Rate" rather than "frequency".

Basically the standards that discuss this are IEC61851-1:2017 and IEC62752. (but we are a start up and cant afford standards)

It is also possible that he means "Cowboy Outfit" rather than "Start-Up".

JimB

 

[Nigel Goodwin]

I believe that the intrepid Flyback means "Sample Rate" rather than "frequency".


It is also possible that he means "Cowboy Outfit" rather than "Start-Up".

JimB

From the questions he asks here I'm dubious any company employing him is going to do well? - and from what he's said previously he never seems to last long anywhere.

 

[Flyback]

Thanks, you can have pulsating DC flowing into the AC mains. The pulsation is at a certain frequency.
I think usually, the DC takes the form of a "gap-tooth 50Hz haversine"...ie, following the mains half cycle, then miss one.....bla bla bla

But the pulsating DC can be at up to 200kHz and beyond.

Our DC leakage current sensros must be able to detect this.......and its mainly the high end type Brq RCDs that are needed to sense this.

 

[Tony Stewart]

I recommend this DC-RCD design http://www.cpdee.ufmg.br/~troliveira/docs/papers/Induscon_2018.pdf

 

[ChrisP58]

Hi,
EV charge points need to detect DC of magnitude 6mA to 300mA.
Though at what frequency must they detect this over?

Also, what test equipment can assure this?

Do you know for instance, what frequencies the metrel tester does the dc leakage test at?

Basically the standards that discuss this are IEC61851-1:2017 and IEC62752. (but we are a start up and cant afford standards)

And how much time and money are you going to waste by trying to play (and win) the game without knowing what the rules are?

Sure, you can guess and ask questions on the internet. But without the standard to start with, there will certainly be questions that won't ask because you don't know that they're important.

Just but the standards.