The recommended answer is still problematic. When there is voltage on the bus, it is not necessary to remove the current transformer, but it must be grounded for the second time. Voltage transformer depends on the specific situation. If it belongs to primary insulation, such as claw type, it can be operated directly. If you want to withstand voltage in stages, you should consider the wiring mode of voltage transformer and the grounding point must be removed. In addition, it must be grounded for the second time, and it doesn't matter whether it is shorted or not. In case of classified insulation, the equipment must be disconnected from the bus.
The withstand voltage shall meet the minimum test voltage required for connecting equipment. If you want to test the bus strictly, you can consider decomposition, but it is generally unnecessary.
Here is a clear concept. When doing AC withstand voltage, it is to test the main insulation. The current here is only capacitive and leakage current, and the working current in normal operation is two concepts. Therefore, it is no problem to short-circuit the voltage (current) transformer twice, but it must be grounded.