With the explosive growth of new energy projects such as photovoltaic (PV) power plants, energy storage systems, and electric vehicle (EV) charging stations, the "DCization" trend of power distribution systems has become increasingly prominent. However, a common misunderstanding persists in selection: directly using AC circuit breakers in DC scenarios, leading to safety hazards like arc extinction failure and protection ineffectiveness. A real case saw an energy storage station suffer millions in losses due to a short circuit caused by mismatched circuit breakers. Though functionally similar in appearance, DC and AC circuit breakers differ fundamentally in design, technical parameters, and application scenarios. This article breaks down their key differences across 5 dimensions to provide practical guidance for new energy project selection.
Core Comparison: 5 Dimensions to Understand DC vs. AC Circuit Breakers
The following table visually contrasts the two types, with supplementary explanations to highlight new energy scenario relevance:
| Comparison Dimension | AC Circuit Breaker | DC Circuit Breaker | Key Impact in New Energy Scenarios |
| Arc Extinction Difficulty | AC current has "zero-crossing points" (once every 10ms), enabling natural arc extinction with simple structure | No zero-crossing points in DC; arcs persist longer with higher energy, requiring specialized extinction mechanisms (e.g., magnetic blowout, vacuum interrupter) | High voltage/current in new energy DC sides (e.g., energy storage systems) increases arc explosion risks with AC circuit breakers, endangering equipment safety |
| Voltage/Current Characteristics | Adapts to AC sine waves; rated voltages typically 220V/380V/10kV | Suits stable DC current; rated voltages up to 500V/1000V/1500V (new energy-specific) with resistance to "commutation impact" | Series-connected PV modules reach DC voltages over 1000V, where AC circuit breakers' insufficient voltage withstand capacity causes insulation breakdown |
| Protection Logic | Focuses on overload and short-circuit protection; tripping curves based on AC load characteristics | Adds "polarity protection," "commutation failure protection," and "DC inrush current suppression" to basic protection | Energy storage systems generate DC inrush currents during charging/discharging; AC circuit breakers lack targeted protection, leading to false tripping or failure |
| Structural Design | Simple arc extinguishing chamber; compact size and low cost | Reinforced arc extinction + insulation design; slightly larger size and higher cost than AC counterparts | New energy projects demand extreme safety; DC circuit breakers' specialized structure ensures long-term stable operation |
| Lifespan & Maintenance | ~10-year lifespan in AC scenarios with low maintenance costs | 8-10-year lifespan in DC scenarios; requires regular arc chamber inspections with higher maintenance standards | Large-scale PV/energy storage plants prioritize long-life DC circuit breakers to reduce downtime and maintenance costs |
Supplementary Explanation:
New energy DC scenarios (e.g., PV string sides, energy storage battery clusters, EV charger DC outputs) feature "no zero-crossing points, high voltage, and large current"—conditions beyond AC circuit breakers' arc extinction and voltage withstand capabilities. This necessitates dedicated DC circuit breakers for new energy applications.
Our new energy-specific DC circuit breakers adopt vacuum arc extinction + magnetic blowout technology (arc extinction time ≤2ms) with rated voltages covering 500V-1500V,they seamlessly adapt to PV, energy storage, and EV charging scenarios.
Practical Selection Principles for New Energy Scenarios
1.Lock Core Direction by Current Type: DC circuits (e.g., PV strings, energy storage battery packs, charger DC outputs) require DC circuit breakers; AC circuits (e.g., inverter outputs, grid connection points, low-voltage distribution loops) use AC circuit breakers—mixed use is strictly prohibited.
2.Refine Selection by Scenario Parameters:
①PV Power Plants: Prioritize DC circuit breakers with "wide voltage adaptation (500V-1000V) + reverse connection protection."
②Energy Storage Systems: Select models with "fast breaking (≤2ms) + inrush current suppression" to avoid battery short-circuit risks.
③EV Charging Stations: Opt for "compact + high protection (IP67)" DC circuit breakers for outdoor installation.
3.Mitigate Risks with Certifications: Choose products compliant with GB/T 14048.3-2017 (DC circuit breaker national standard), CE (for European markets), and UL (for North American markets) to meet new energy project compliance requirements.
Case Study: Risks of Wrong Selection vs. Value of Correct Choice
A 100MW PV power plant initially used AC circuit breakers on the DC side to cut costs. A fire caused by arc extinction failure occurred after 3 months of operation, resulting in 2 million yuan in direct losses. After switching to dedicated DC circuit breakers, the plant has operated stably for 2 years without faults. Another energy storage project utilizing our 1500V DC circuit breakers successfully avoided 3 battery cluster short-circuit risks via fast breaking, reducing maintenance costs by 40% compared to industry averages. These cases confirm that correct circuit breaker selection ensures safety and long-term cost savings in new energy scenarios.
Conclusion: Conversion Guidance + Resource Empowerment
Power distribution safety in new energy projects starts with proper circuit breaker selection. As a specialist in circuit breaker solutions, PEOPLE offer a full range of DC circuit breakers for PV, energy storage, and EV charging applications, supporting customized parameter design. Please contact our technical consultants for free project-specific selection support!
Post time: Feb-02-2026
