A DC isolator is a key component for ensuring the safe and stable operation and maintenance of DC circuits. It can achieve the conduction and disconnection of the circuit through physical isolation during the operation of the DC system. When equipment maintenance, repair, or an emergency failure occurs, it can quickly disconnect the circuit, ensuring the safety of personnel and preventing the expansion of failures.
The BHK series DC isolators are specifically developed for new energy application scenarios. They have characteristics such as high voltage resistance, arc resistance, and long service life, and are core protection devices in fields such as photovoltaic power generation, energy storage systems, and electric vehicles.
Current Nature：AC isolators are used in AC circuits where the current direction reverses periodically. When cutting off the circuit, the arc can be automatically extinguished due to the natural zero - voltage crossing of the alternating current. DC isolators are used in DC circuits. Since direct current has no natural zero - crossing point, special technologies are required to force the extinction of the arc.
Application Scope：AC isolators have a very wide range of applications, from low - voltage residential systems (120V/230V) to high - voltage industrial equipment (several thousand volts). DC isolators usually have a higher rated voltage. For example, in solar photovoltaic systems, they need to support voltages above 1000V DC to reduce energy losses on the lines.
Switch Design：AC isolators have a relatively simple structure with small contact gaps, which reduces their manufacturing costs and makes them suitable for conventional power scenarios. DC isolators, due to the need to deal with higher voltages and more complex working conditions, require larger contact gaps and use arc - resistant materials, resulting in a higher structural complexity.
Renewable Energy Power Generation Systems
In photovoltaic, wind power generation, and energy storage systems, DC isolators play a significant role. In photovoltaic systems, they are installed on the DC side between the photovoltaic string and the inverter to cut off the current during maintenance work and effectively avoid arc risks. In energy storage batteries, they are installed between the battery pack and the power conversion system (PCS) to provide safety isolation and prevent the spread of short - circuit or overload failures. In wind power generation, they are used to isolate the DC bus or the pitch system to ensure the safety of maintenance personnel.
Electric Vehicle Charging Facilities
Inside the charging piles, DC isolators are used to isolate the DC charging gun from the vehicle battery and can quickly cut off the high - voltage circuit of 400V - 1000V in case of an emergency. During vehicle maintenance, they can disconnect the connection between the battery and the motor/charging system to prevent electric shock risks.
Rail Transit and Traction Power Supply
In catenary/third - rail isolation, DC isolators cut off the connection between the vehicle and the power supply track to ensure no residual voltage during maintenance. In the on - board system, they can isolate the traction converter from the drive motor to protect the equipment from short - circuit or over - current damage. For energy - storage - type rail vehicles, they can also manage the charging and discharging circuits of supercapacitors or battery packs.
