DC circuit breaker and on-load voltage regulation refer to the transformer tap changer voltage regulation mode. The difference is that the non-excitation voltage regulator switch does not have the ability to load shift gears, because the tap changer is in the process of shifting gears. There is a short-time disconnection process. Disconnecting the load current will cause the arc between the contacts to burn out the tap changer or short circuit. Therefore, the transformer must be powered off during the shift. Therefore, it is generally used for transformers that do not require strict voltage requirements and do not require frequent shifting. The on-load tap-changer can be used to switch the gear position, because the on-load tap-changer does not have a short-time disconnection process during the shifting process, and transitions from one gear to another after a transitional resistance transition. Therefore, there is no arcing process in which the load current is disconnected. It is generally used for transformers that require strict voltage regulation for voltage requirements.