Zero sequence current transformer for 35kV and below voltage systems. Used for cable ground protection in small grounding current systems. Rated frequency 50Hz or 60Hz. Available in Φ75, Φ110, Φ125 inner diameter sizes. Primary insulation guaranteed by cable, secondary winding insulation tested. Compliant with IEC 61869 and GB/T 20840 standards. Matching relay model DL-11/0.2, epoxy resin cast construction.
Zero-sequence current transformer for 35kV and below systems, designed for cable ground fault protection in small grounding current systems. Suitable for outdoor pole-mounted circuit breaker applications.
| Parameter | Specification | Verification |
|---|---|---|
| Product Type | Current Transformer | IEC 61869, GB/T 20840 |
| Model Code | LJZ-75-110-125 | Factory nameplate marking |
| Primary Voltage | Up to 35kV | Rated voltage test (IEC 61869-1/3) |
| Secondary Voltage | [On Request] | Ratio check at rated frequency |
| Accuracy Class | [On Request] | Accuracy test (IEC 61869-2 / IEEE C57.13) |
| Rated Burden | [On Request] | Burden test at rated VA |
| Insulation Type | Dry Epoxy Resin | Dielectric tests per standard |
| Insulation Level (BIL) | [On Request] | Power-frequency & lightning impulse withstand |
| Standards | IEC 61869, GB/T 20840 | Certified to listed standards |
| Frequency | 50/60Hz | Per IEC 61869-1 |
| Environment | Epoxy resin cast | Per datasheet limits |
Ideal For
Not Recommended For
Connect secondary terminals 1S1 and 1S2 to the protection relay. Never open-circuit the secondary of a CT while energized - hazardous voltage. Ground the secondary winding at one point. Ensure the primary cable passes through the CT window (Φ75/Φ110/Φ125) and is properly insulated for the system voltage.
Compliant with: IEC 61869, GB/T 20840
S_total = ΣS_instrument + I₂² × (ρ × 2L / A)
Q: What is the primary voltage rating?
A: Up to 35kV.
Q: What are the available inner diameters?
A: Φ75, Φ110, and Φ125.
Q: What standards does it comply with?
A: IEC 61869 and GB/T 20840.
Missing fields are marked [On Request] — never fabricated. M2/M5/M6 verification rows follow IEC 61869 / IEEE C57.13 conventions.
| Connecting lead resistance (Ω) | Total secondary external impedance (Ω) | Relay pickup current (A) | Sensitivity (A) | Relay scale (A) |
|---|---|---|---|---|
| 1 | ≤10 | 0.1 | ≤10 | 0.1-0.2 |
Dimension & outline drawing of LJZ-75-110-125 — click image to zoom / view original.
