What is the recommendation for protecting the VAP, VAN, IAP-IFP and IAN-IFN inputs of the ADE7816? Previously it has been recommended to use back-to-back diodes to ensure the maximum voltage across the inputs does not exceed +/-2V. Is this still the suggested approach? If not, please provide the recommended protection scheme. Thanks,
If the recommended anti-alias filter(1K or larger) is used the internal esd protection is enough to protect the part. Diodes are not required. The 2v max spec will be limited by the 1K and esd diode drops. You will still rail the modulator but it will recover after event is over.
Thanks for your answer, however would it be possible to elaborate on the details of the internal esd protection diodes; what rails they are connected to and the current handling capability. I would like to confirm that even with severe overloads on the CTs (say a monentary short on the primary) that such an event would not cause any permanent damage.
Can you give me some information of the CT you are using? Most measurement ct can only deliver so much power then they saturate. The series resistance of the ct will also limit the max current the ct can output. The current the esd structures will see is the voltage across the burden - esd drop / 1K series resistor. The max voltage under a short circuit condition depends on the ct and the burden resistor.
https://www.crmagnetics.com/Assets/ProductPDFs/CR8400%20Series.pdf for reference.
We are using split core CTs from YUANXING that have 0.333V output. Link to datasheet is