Case Sharing: CT ratio on CT Can’t Match Smart Meter CT Ratio

CT ratio can’t match smart meter

Phenomenon

Smart meter data can’t match real current data via clamp meter

Smart display 3 phase current

Real Clamp meter data

Reason Analysis

Based on smart meter model below, we know that it is 40mA accuracy smart meter, it means that CT ratio must be **/40mA like 120A/40mA,200A/40mA , 100A/40mA

However, CT ratio of real CT is 500/5

Solution

Either change smart meter or change CT ratio. In the case, as original CT from Growatt can’t make cable go through. so we can change Smart meter as below. which can be used for CT */5 A

SDM 630MCT V2

summary

1. Two smart meter models below can connect */5A CT.

SDM 630MCT V2

SDM 630MCT-ETL

2. Before you buy smart meter and CT, please confirm your cable dimension, smart meter CT ratio and give presale engineer feedback about it, or your cable can’t go through the CT. That will waste much time and money.