Can a 10KV high-voltage switchgear be used in a 6KV system, and what modifications are required?
Thread Content
I would like to ask everyone: a complete power supply system that reduces voltage from 110 KV to 10 KV, including transformers, GIS units, and high-voltage switchgear, is to be used in another project where the incoming voltage is 35 KV and the outgoing voltage is 6 KV. My questions are: 1. Can the 10 KV high-voltage switchgear be used in a 6 KV system, and if so, what modifications are required? 2. I would like to ask whether a transformer that converts 110 KV to 10 KV can be modified to convert 35 KV to 10 KV. I don’t think it’s very feasible; those who are experts in this field, please give me some advice from technical, economic, and safety perspectives.
The voltage levels are different, so the voltage tolerance and current capacity of the components also vary; it’s better to design a set specifically for this.
Ahah, this question from this sea friend is quite complex, involving many aspects! Why is it still necessary to make use of existing high-voltage cabinets when the power supply system changes? Firstly, the original system was 110KV/10KV, and both the impedance and short-circuit capacity of the system have changed fundamentally compared to the new 35KV/6KV system. With the new system, the short-circuit capacity of the high-voltage switch (i.e., the current it can interrupt) has changed, and at the same time the rated capacity of the switch has also changed. That’s why no one can give you an accurate answer to your question! It is possible to make use of existing assets only after re-designing and calculating the new power distribution system. If so, and the number of existing medium-voltage distribution cabinets is not large, it is highly recommended to design and use new medium-voltage cabinets!
The modification is feasible: 1) Using a 10kV high-voltage cabinet in a 6kV system, the main change is to replace the current transformer； 2) The original transformer was 110/10 kV, and its voltage transformation ratio did not match 35/10; sending the original transformer back to the manufacturer for modification to achieve a suitable voltage ratio is a reliable approach.
More professional, getting to the core of things
The 3rd floor is correct. Whether the high-voltage cabinet can be reused depends on whether the short-circuit tolerance of the existing switchgear, as well as the short-circuit breaking capacity and rated current of the circuit breakers, meet the requirements of the 6kV system. Because at the same power level, the current at 6 kV is significantly higher than that at 10 kV. If the short-circuit capacity of the switchgear meets the requirements, 10kV switchgear can be used in 6kV systems. It’s not just the current transformer that needs to be replaced; the voltage transformer also needs to be replaced.
Of course, it’s possible to discuss using 10 instead of 6. If the short-circuit current is sufficient, just modify the CT