Why Choose Projoy's PEFS Photovoltaic Rapid Shutdown?

The Risk of DC Arc in Photovoltaic Systems

In photovoltaic power stations, light illuminating solar panels generates voltages of 600-1500V on the DC side. While inverters have built-in DC isolators, they cannot address the DC power between the panels and the inverter. Long-term operation can lead to DC arc phenomena due to issues like unfastened joints, contact quality problems, or aging insulation. Unlike AC arcs, DC arcs lack a zero-crossing point, allowing them to sustain combustion and reach temperatures up to 3000°C, posing a significant fire risk. Even with a low probability (1/1000), a 10MW station could experience 80 DC arc events over 25 years. Preventing fire risk and enabling non-professionals to identify and mitigate these risks is a major concern in the photovoltaic industry.

Global Response to Photovoltaic DC High Voltage Safety Standards

Developed countries like the United States, Europe, Japan, and Australia have introduced compulsory measures for DC high voltage in photovoltaic systems.

Projoy PEFS Series: String Level and Panel Level Solutions

Projoy offers PEFS-EL (string level) and PEFS-PL (panel level) rapid shutdown solutions based on market demand.

A diagram illustrates a photovoltaic system with multiple solar panels connected in series. The DC output from the panels feeds into PEFS-EL units, which then connect to an AC Electric Box and an On-grid Inverter. The system is shown connected to the grid, with a representation of a fire scenario where firefighters are present.

Projoy's PEFS-EL String Level Rapid Shutdown Solution

The PEFS-EL series is suitable for residential, industrial, commercial, and large-scale photovoltaic systems, supporting 1-2, 3-6, or 7-12 strings. It handles a maximum loop voltage of 1500VDC and a maximum loop current of 55A. The built-in temperature sensor triggers automatic shutdown if the internal temperature exceeds 70°C. In case of fire, after AC power is turned off, the PEFS-EL can shut down signals from the power grid. The disconnection switch automatically turns off if power failure exceeds 5 seconds, subsequently cutting off DC power.

Key Features of PEFS-EL:

• Max. loop voltage: 1500Vdc, max. loop current: 55A; supports 2-12 strings shutdown.
• Optional IP65 rated casting plastic shell.
• Active control for safety and reliability.
• Fire and flame retardant UL94-V0 / anti-UV material.
• High-quality materials for improved resistance to high temperature, corrosion, and impact.
• External slide block mounting hole design for easy installation.
• DC interface with knock-out holes, glands, MC4 connectors (optional).
• Built-in ventilate valve to prevent condensation.
• Built-in isolator switch with TUV, CE, CB, SAA, UL certifications.

Projoy PEFS-PL Panel Level Rapid Shutdown Solution

Projoy's PEFS-PL series offers panel-level quick shutdown, with each device serving one or two panels. When installed, panels can be left open. In emergencies, the AC switch or a quick-off button can be used to shut down panels, ensuring personnel safety for the system or firefighters.

A diagram shows multiple solar panels, each labeled with '≤40V'. These panels are connected to PEFS-PL devices. The DC outputs from the PEFS-PL units are consolidated and connected to a PLC Box, which then connects to an Inverter. The system is shown connected to the grid.

Key Features of PEFS-PL:

• Lightweight design with buckle installation for simple and convenient panel mounting.
• Complies with UL, NEC 2017/2020 (690.12), and SUNSPEC agreements.
• Matches inverter LVRT (Low Voltage Ride Through) features.
• Optional PLC control or DC24V power control.
• Available in one-for-one or one-for-two configurations.
• Available colors: White, Orange, Black.
• Built-in temperature sensor for automatic shutdown above 85°C.
• Fire and flame retardant UL94-V0 / anti-UV material / IP67 protection grade.
• High-quality materials enhance resistance to high temperature, corrosion, and impact.
• Automatic reset function: automatically closes after power is restored, no manual reset needed.

Comparison: Projoy PEFS Series vs. A Certain Brand DFS Series