Why can arc detection compensate for the shortcomings of traditional measures?

Let’s start with the most common issues in PV power plants and compare why arc detection can make up for the shortcomings of traditional measures, using the actual performance of Fonrich’s equipment as a reference.

1. DC Arc Prevention: Traditional Measures Are "Blind," Only Arc Detection Works!

This is the most critical gap—80% of electrical fires in PV power plants are caused by DC arcs, but ordinary breakers and fuses cannot detect them at all:

• Ordinary DC breakers: Can only detect "excessive current." The current of DC arcs usually does not reach the overload threshold, so they are like "being blind" while the arc burns.

• Fuses: Only break when the current is high enough to melt the fuse wire. The current of DC arcs is insufficient to trigger this, so fuses have no response.

• Arc detection equipment (e.g., Fonrich’s string-level breakers): Specifically targets the "unique signals" of DC arcs. Whether it is a weak arc from a hidden module crack or a strong arc from loose wiring, it can cut off power in 0.05 seconds.

2. Fault Localization: Traditional Measures "Shut Down Everything," Arc Detection Pinpoints to a Single Panel!

After traditional measures trip, you cannot identify where the fault is—you have to check one by one, which delays power generation. Arc detection enables precise localization and saves a lot of effort:

• Ordinary DC breakers: For example, if 3 strings share one breaker in a combiner box, a fault in one string will shut down all 3 strings. Maintenance technicians have to disconnect and inspect the wires of the 3 strings, and it takes a long time to find the fault point.

• Fuses: Even if a fuse burns out, you cannot tell which string has the problem. You have to test the continuity of each string one by one, which is very troublesome.

• Arc detection equipment: With Fonrich’s module-level optimizers, if an arc occurs in a panel, the monitoring platform will directly display "Fault in Panel 8 of String 5." Technicians can directly replace the panel and complete the repair in half an hour; string-level arc detection can also locate the specific faulty string, eliminating blind work.

3. "PV-Specific Scenarios": Traditional Measures Tend to Mis-Trip or Fail to Trip, Arc Detection Is Smarter!

PV power plants have large fluctuations in power generation current during the day and frequent shading. Traditional measures often "trip blindly" (trip for no reason) or "fail to trip" (fail to trip when a fault occurs), while arc detection can distinguish between normal fluctuations and faults:

• Ordinary DC breakers: Are prone to mis-tripping due to current fluctuations caused by inverter startup or cloud shading—there is no fault, but power generation stops; when facing low-current DC arcs, they fail to trip.

• Fuses: Do not mis-melt when current fluctuates greatly, but still have no response to real arcs.

• Arc detection equipment (Fonrich): Uses "PV-specific" algorithms to distinguish between "normal fluctuations from inverter startup" and "fault arcs." Its mis-trip rate is below 0.05%, which is 80% lower than the industry average.

4. Service Life & Maintenance: Traditional Measures "Consume Many Parts," Arc Detection Is More Hassle-Free!

From the perspective of long-term use, arc detection has lower maintenance costs and no need for frequent part replacement:

• Fuses: Are disposable—once burned, they must be replaced. A single power plant needs to prepare dozens or even hundreds of fuses a year, which adds up to a considerable cost.

• Ordinary DC breakers: Their contacts are prone to oxidation and need to be replaced after 3–5 years; otherwise, poor contact will instead cause arcs.

• Arc detection equipment (Fonrich): Its shell is UV-resistant, high and low temperature resistant, and not easy to oxidize; it also has built-in monthly self-inspection—if there is a problem, it will alert in advance, eliminating the need for frequent disassembly and inspection of the box.

Cost Comparison: The annual maintenance cost of traditional measures (breakers + fuses) for a 1MW power plant is about 20,000 THB; with Fonrich’s arc detection equipment, the annual maintenance cost is less than 5,000 THB, saving 150,000 THB in 10 years.

3. Key Conclusion: It’s Not "Either/Or," but "Arc Detection + Traditional Measures" for Sufficient Safety!

After seeing the comparison, it does not mean that traditional measures are useless—they just have "inherent shortcomings": they cannot prevent DC arcs and cannot locate faults accurately. Arc detection just makes up for these shortcomings. Therefore, reliable PV power plants now adopt "multi-layer protection":

• Module level: Install Fonrich optimizers (with arc detection) to prevent arcs in individual panels and increase power generation.

• String level: Install Fonrich string-level arc detection breakers to prevent arcs in entire strings and enable precise localization.

• Inverter side: Keep ordinary DC breakers (to prevent overloads and short circuits) and add Fonrich’s inverter-side arc detection breakers for dual protection.

• Old power plant retrofits: There is no need to remove the original ordinary breakers—directly install Fonrich’s string-level arc detection breakers in the combiner box to fill the gaps at low cost.

Related Q&A

Q: I have a 10kW residential PV system with ordinary breakers—do I still need arc detection?A: You must add it! Residential PV systems are installed on rooftops, close to living areas—once a fire breaks out, the risk is even greater. It is recommended to install Fonrich’s module-level optimizers (with arc detection), which can prevent arcs caused by hidden module cracks and loose wiring, and also solve the problem of rooftop shading, increasing power generation by 15%. The cost can be recovered in half a year.

Q: Arc detection equipment is more expensive than ordinary breakers—can small power plants afford it?A: They can afford it! Fonrich has packages for small power plants. For power plants under 100kW, the total cost of string-level arc detection breakers and module-level optimizers is only 30,000–50,000 THB more than that of ordinary solutions. However, this investment can prevent fire losses (a single fire costs at least 100,000 THB), and the long-term maintenance cost is low—it is very cost-effective when calculated comprehensively.

Q: If arc detection is installed, do we still need to keep the traditional ordinary breakers?A: You must keep them! Arc detection mainly prevents DC arcs, while ordinary breakers prevent overloads and short circuits—they have different functions, and using them together ensures comprehensive protection. For example, if a sudden short circuit occurs in the power plant and the current is too high, the ordinary breaker can trip quickly; if the current is small (such as a DC arc), the arc detection equipment can cut off the power. No matter what kind of fault occurs, there is protection.