✅ Transformer De-energization Sequence (Power-Off)
The general rule is: Low Voltage (LV) side first, then High Voltage (HV) side.
Step-by-step:
Open all LV circuit breakers – Disconnect all loads on the low voltage side.
Open LV disconnector / isolator (if any) – To create a visible break on the LV side.
Open the HV circuit breaker or load break switch – Finally disconnect the power supply on the high voltage side.
⚡ Why this order?
| Reason | Explanation |
|---|---|
| Protect equipment | When LV side is opened first, the transformer only carries no‑load current when HV is opened. This minimizes switching overvoltage and inrush current, protecting transformer insulation. |
| Protect personnel | If an LV breaker fails to open due to a fault, opening HV under load could generate a dangerous arc. By opening HV last, you ensure the transformer is under no‑load condition, making the operation much safer. |
✅ XDTZ Related Product
JDZX9-35 Voltage Transformer
1.Rated voltage：40.5kV
2.Accurate level:0.2/0.5/6P
3.Primary voltage:35/√3
4.Secondary voltage：100/√3 100/3
5.Rated insulation level:40.5/90/200kV
Our address
No. 1 East Gaoxin Avenue in the High-Tech Development Zone of Baoji City, Shaanxi Province, China
Phone Number
+86 180 9176 5658
xdtz03@westpowerelectric.com
