Problem of reverse power supply to transformers
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For a power transformer that converts 10KV to 380V, what will happen if 380V is applied to the low-voltage side?
When a 380V voltage is applied at the low-voltage side of the power transformer, whether it is possible to generate a 10KV voltage at the high-voltage side depends on the parameters of the transformer, specifically the voltage level on the high-voltage side. 1. If the parameters of the power transformer are 10 KV on the high-voltage side and 380 V on the low-voltage side, then by applying 380 V at the low-voltage side, the high-voltage side can output a voltage of 10 KV. 2. If the parameters of the power transformer are 6 KV or 30 KV on the high-voltage side, and 380 V on the low-voltage side, then by applying 380 V at the low-voltage side, the high-voltage side can output either 6 KV or 30 KV voltage.
It can output 10 kV; a colleague of mine was once injured by an electric shock due to this!
Ahah, my suggestion for this sea friend is: reverse power supply from the transformer, with the primary voltage being the same as the rated value – which is of course 10KV! However, it’s essential to make sure that this kind of reverse power transmission is carried out as little as possible! Sending electricity in the reverse direction can create many safety hazards! Of course, proper safety measures should be in place (to prevent operation alongside other systems and to avoid personal injury, etc.); using reverse power supply from transformers for the testing and calibration of the high-voltage side busbars is also a viable option as a debugging method during the construction phase.
Reverse power transmission means that the original primary side becomes the secondary side, and the secondary side becomes the primary side. The turns ratio remains unchanged.
Is this reverse power transmission a purposeful return?
Check the transformer turns ratio. It is usually a step-down transformer with a ratio of 10/0.4. The low-voltage side has an input of 380V, while the high-voltage side is around 9.5kV
Two transformers were operating in parallel; the high-voltage side of one transformer lost power, yet the switch on the low-voltage side of that transformer was not turned off, resulting in reverse power flow