Application Solutions of DC Circuit Breakers in the New Energy Sector

I. Overview​
With the rapid development of new energy power generation and electric vehicle (EV) charging facilities, DC systems have imposed higher requirements for safety protection equipment. Traditional AC circuit breakers cannot effectively interrupt DC fault currents, creating an urgent need for specialized DC circuit breaker solutions. This solution provides professional protection configurations for two major application scenarios: photovoltaic (PV) power generation systems and EV charging piles.

​II. DC Protection Solution for PV Power Generation Systems​

1. ​Analysis of Application Challenges​
   • Short-circuit currents on the DC side of PV arrays can reach up to 20 kA, exceeding the breaking capacity of traditional circuit breakers.
   • DC arc faults can easily cause fire accidents.
   • Fault localization is difficult, with an average troubleshooting time of over 2 hours.
   • AC circuit breakers face challenges in arc extinction and slow breaking speed in DC applications.
2. ​Solution Features​
   Core equipment: 1500V DC dedicated circuit breaker
   • Utilizes magnetic blowout arc extinction technology to effectively interrupt DC fault currents.
   • Integrates anti-islanding protection for PV systems to ensure grid maintenance safety.
   • Built-in Arc Fault Detection Module (AFCI) to effectively prevent DC arc fires.
   • Modular design supports quick replacement, reducing maintenance time.
3. ​Technical Parameters​
   • Rated voltage: DC 1500V
   • Breaking capacity: 25 kA (exceeding the maximum short-circuit current of PV systems by 20%)
   • Protection rating: IP65 (outdoor type), suitable for harsh environments
   • Operational lifespan: ≥8,000 cycles
   • Fault localization: Supports remote communication and fault indication.
4. ​Implementation Results​
   A case study of a 100MW PV power plant shows:
   • Fault localization time reduced from 2 hours to 5 minutes.
   • Annual average fault downtime reduced by 45%.
   • DC-side fire risk reduced by 70%.

​III. DC Protection Solution for EV Charging Piles​

1. ​Analysis of Application Requirements​
   • Supports high-power fast-charging systems above 350 kW.
   • Prevents DC short-circuit faults during charging.
   • Compatible with mainstream charging protocol standards.
   • Addresses temperature rise issues caused by high-current operation.
2. ​Solution Features​
   Core equipment: Liquid-cooled DC circuit breaker
   • Uses liquid cooling technology to support a continuous current of 500A.
   • Integrates charging communication protocols such as CCS/CHAdeMO.
   • Intelligent overtemperature protection system (automatically reduces load at 85°C).
   • Two-level protection architecture: main circuit breaker + branch protection.
3. ​Technical Parameters​
   • Rated voltage: DC 1000V
   • Rated current: 500A (main circuit breaker), 250A (branch protection)
   • Breaking time: <5 ms (ultra-fast protection)
   • Operational lifespan: 10,000 cycles (meets high-frequency usage demands)
   • Communication interface: CAN bus/Ethernet
4. ​Typical Configuration​
   350 kW charging pile protection solution:
   • Main protection: 500A liquid-cooled DC circuit breaker (1 unit)
   • Branch protection: 250A DC circuit breaker (2–4 units)
   • Supports simultaneous fast charging with 4 guns without interference.

​IV. Summary of Technical Advantages​

1. High breaking capacity: 25 kA breaking capacity meets the needs of various DC systems.
2. Fast breaking: <5 ms breaking speed effectively limits fault propagation.
3. Smart integration: Combines arc detection, temperature protection, and communication functions.
4. High reliability: IP65 protection rating and long service life design.
5. System compatibility: Supports mainstream PV systems and charging pile standards.

​V. Conclusion​
This DC circuit breaker solution addresses the specific needs of the new energy sector by providing specialized DC fault protection equipment. It effectively resolves DC system breaking challenges, significantly enhances system safety and operational reliability, and offers critical safety support for PV power generation and EV charging infrastructure.