With the development of the solar photovoltaic industry, the photovoltaic industry is becoming more and more important in the energy field. Photovoltaic equipment such as photovoltaic panels and inverters are costly, and if affected by electrical surges, resulting in significant economic losses and the shutdown of photovoltaic system operations, a large amount of electrical energy and money will be lost. Surge protection is therefore essential in photovoltaic systems.
Using adapted Solar PV SPD is one of the measures to protect the safe and stable operation of photovoltaic systems. This protects the PV system from transient overvoltage and also reduces the maintenance cost of the PV system. A variety of Solar PV SPD solutions protect photovoltaic systems of different types and sizes.
What is a Solar PV SPD?
Solar PV SPD (Surge Protective Device) is a key component specially designed to protect electrical equipment in photovoltaic systems from electrical surges. These electrical surges may come from direct lightning strikes or overvoltage in the Electrical grid. By installing SPDs at each node of the photovoltaic system, these electrical surges are monitored and guided underground through ground wires, thereby protecting the safety of valuable equipment.
How does SPD protect the DC side of solar photovoltaics?
Install specific DC SPDs on the DC side of solar photovoltaics. The DC side is a very important part of the photovoltaic system, this is where the solar photovoltaic panels and the inverter are connected.
When a surge occurs, the SPD will detect an excess of normal operating voltage and guide these overvoltages underground through internal components through ground wires to prevent excessive voltage from damaging equipment such as inverters. When the voltage returns to normal operating value, the SPD will automatically return from the low impedance state to the high impedance state and continue to monitor the voltage to respond to the next electrical surge event.
How many surge protectors are needed for a photovoltaic system?
On both the DC and AC sides of the solar photovoltaic system, multiple SPDs need to be installed at different points. The total number of SPDs required is related to the length of the photovoltaic system line. You can refer to the distance between the panel and the inverter.
Install SPD at the photovoltaic array to protect the energy storage power supply and inverter behind the DC line. It is important to install SPDs under each small group of photovoltaic panels in large, widely distributed photovoltaic arrays, which are larger and more susceptible to lightning strikes. If a photovoltaic combiner box is used in the photovoltaic system, SPD can also be installed in the photovoltaic combiner box.
Install SPD at the DC input end and AC output end of the inverter, and pay attention to selecting the appropriate DC SPD and AC SPD. This protects the inverter from surge currents from the photovoltaic array, as well as from surge currents from the power grid or AC load equipment.
Install SPD in the AC distribution box to provide more complete protection for the photovoltaic system. For more complex systems, where the distance between PV system components is longer and AC supplies the load equipment in the building, SPDs can also be installed near the load equipment.
The number and type of surge protective devices are determined by the size of the actual application scenario, the length of the cable, and the specific electrical equipment. Thor can be consulted for a specific analysis of your PV system to provide comprehensive surge protection.
How to choose the right SPD for solar PV systems?
Before choosing an SPD, you need to understand and confirm the configuration of the photovoltaic system and the components to be protected. Photovoltaic systems have unique characteristics, with DC voltages up to 1500V, so an SPD specifically designed for solar photovoltaic systems is required.
Type 1 SPD is used to protect against large surge currents such as lightning strikes, and is suitable for installation at main power entry points, such as energy storage power supplies and photovoltaic arrays. If the photovoltaic system is located in an area with a high risk of lightning strikes, installing Type 1 SPD at the input end of the inverter can also be considered.
Type 2 SPD is used to protect against switching surges and as a second layer of protection, suitable for installation in distribution boxes. Type 2 SPD is a common choice because it protects against common surge types such as switching surges. Type 1+2 SPD combines the characteristics of Type 1 SPD and Type 2 SPD, making it a more versatile choice. To play a protective role, the voltage protection level (UP) of the SPD should be less than the impulse withstand voltage rating of the system equipment, generally, there should be a 20% difference.
Plan the installation locations of different types of SPDs in solar photovoltaic systems. Common installation locations include combiner boxes, AC distribution boards, and near inverters.