## Accuracy Class for Current Transformers

| Published: April 16, 2019 – 5:18 pm

The Shandong Yuanxing current transformers are designed for the accurate measurement of AC currents up to 120% of the rated primary current. The accuracy of the primary current to secondary signal transformation (either current or voltage) is stated as Accuracy Class. The Accuracy Class for the current transformers is measured in accordance with the IEC61869 standard. The IEC61869-2 standard specifies transformation accuracy for current transformers at different percentage levels of rated primary current and secondary burden levels.

**IEC61869 Accuracy Class 0.2:**

- 0.75% ratio error @ 5% of rated primary current,
- ±0.35% ratio error @ 20% of rated primary current,
- ±0.20% ratio error @ 100% of rated primary current
- ±0.20% ratio error @ 120% of rated primary current

**IEC61869 Accuracy Class 0.5:**

- ±1.50% ratio error @ 5% of rated primary current,
- ±0.75% ratio error @ 20% of rated primary current,
- ±0.50% ratio error @ 100% of rated primary current
- ±0.50% ratio error @ 120% of rated primary current

The Accuracy Class requirements as applied to a specific model of a current transformer may limit the rated primary current ranges that can meet those accuracy requirements.

**Example: CTSB0816 Split-core Current Transformer Accuracy Class 0.5:**

Accurate measuring range is 5%-120% of rated primary current, for rated primary currents from 500A-2,000A (e.g. models CTSB0816-500A/ 5A to CTSB0816-2000A/ 5A).

- CT rated primary current of 500A: Class 0.5 measurement range would be 25A to 600A.
- CT rated primary current of 2,000A: Class 0.5 measurement range 100A to 2,400A

Accurate measuring range is 1%-120% of rated input current, for rated primary currents from 2,000A-5,000A;

- CT rated primary current of 2,000A: Class 0.5 measurement range would be 20A to 2,400A.
- CT rated primary current of 5,000A: Class 0.5 measurement range 50A to 6,000A

TC