Photovoltaic power generation system consists of photovoltaic panels, junction boxes, inverters, distribution cabinets, batteries and corresponding bus control systems. Due to the coupling surface, system structure and special outdoor installation environment, photovoltaic systems face the risk of lightning strikes and surge voltages:
- Due to the exposed characteristics of the photovoltaic array installation location, the risk of direct lightning strikes is high;
- Direct lightning strikes (direct strikes on photovoltaic panels), indirect effects (surge effects on photovoltaic components, junction boxes, inverters, etc.) on other lines (direct strikes or surge effects on signal lines);
EYZAO provides a full set of high-quality and reliable surge and lightning protection solutions for photovoltaic systems, and installs surge protectors on the DC side of the inverter, DC distribution cabinet, DC junction box, AC side of the inverter and main distribution box.
Key points for selecting surge protection for photovoltaic systems:
- Anti-breakdown capability: To prevent breakdown, the flow rate is the key parameter of SPD;
- Tripping capability: Timely tripping when SPD fails can avoid combustion accidents. How to ensure timely tripping is a problem that must be considered when designing SPD;
- Arc extinguishing capability: In photovoltaic DC systems, the frequency of voltage and current is constant and not at the zero-crossing point of the phase. Compared with SPDs in AC systems, when SPDs in DC systems trip, the arc generated is not easy to extinguish by itself, which can easily cause the combustion of SPDs. This is not allowed for both the SPD itself and the protected system. The DC SPD used for photovoltaics must have extremely high arc extinguishing capability.
- Harmonic resistance: Factors such as AC/DC inverters and nonlinear loads will cause harmonics, which will cause the voltage to rise to more than kilovolts for a long time. SPDs must have harmonic resistance to ensure that they are not damaged.
Standards based on
- EN 50539-11 “Surge Protective Devices for Photovoltaic Systems”
- IEC 61643-31 “Surge Protective Devices for Photovoltaic Systems”
- IEC 61643-32 “Application and Selection of Surge Protective Devices Connected to the DC Side of Photovoltaic Systems”
- IEC 62305 “Lightning Protection” Series of Standards
- IEC 61312 “Protection against Lightning Electromagnetic Pulses”
- IEC 61643-11 “Surge Protective Devices Connected to Low Voltage Distribution Systems”
- GB 50057 “Lightning Protection Design Specifications for Buildings”
