Solar pv system in lightning protection and grounding system installation and construction
First,the installation of lightning protection devices
1, the lightning protection device installation method.
Relatively simple to install lightning protection devices,lightning protection module, spark discharge gap module and alarm module,can be easily installed directly into the mix and distribution box in a standard 35 mm rail.
2, determine the location of lightning protection installation.
In general, the SPD should be installed lightning protection in accordance with district requirements to determine the partition at the junction of the theory. Class B (Ⅲ level) mine is usually installed in the cable into the building's entrance,for example, installed in the main power distribution cabinet. Class C (Ⅱ grade) mine is usually installed in the distribution cabinet, as a basic protection to add. Class D (Ⅰ level) mine are of fine grade lightning protection, should be protected as much as possible close to the device-side installation.Partition theory and lightning arrester rating is based on DIN VDE0185 and IEC 61312-1 and related standards determined.
3, the electrical connection.
SPD connecting wires must be kept as short as possible to avoid wire resistance and inductance generate additional residual pressure drop.If on-site installation cable length can not be less than 0.5m, then the SPD's connection must use the V-shaped connected. Meanwhile, the wiring must be lightning input lines and output lines as much as possible to maintain more long-distance arrangement.
Additional wiring to the attention of the line will have been protected and unprotected lines (including the grounding line),never close parallel arrangement, the arrangement of them must have a certain distance or shielding device isolation, has never been protected to prevent line to have induced lightning surge protection circuit current.
SPD cable cross-sectional area and distribution system should be the phase line and zero line (L1, L2, L3, N) cross-sectional area of the same.
4, neutral and ground connections.
Zero line connection can be diverted considerable lightning current in the main distribution cabinet,the zero line of the cable cross-sectional area of not less than 16 mm2,when electricity consumption in some smaller systems,the zero line of the cross-sectional area You can choose a smaller more appropriate. SPD grounding wire cross-sectional area and generally cross-sectional area of half the main circuit.
5,grounding and bonding.
SPD and the equipment grounding wire must be grounded protective grounding wire or the system reliable connection. If there is lightning protection equipotential bonding system, lightning protection device must be the ultimate ground and equipotential bonding system,reliable connection. Each partial system must also equipotential row and row of the main equipotential bonding reliable connection,cable cross-sectional area must meet the minimum cross-sectional area grounding requirements.
6, the SPD's fail-safe method.
Based on electrical safety reasons,any parallel mains power supply installed in the relative zero or relatively between the electrical components,in order to prevent short circuit fault,the electrical components must be installed before the short circuit protection devices, such as air switch or fuse. Lightning is no exception, in the SPD into the line of, must also install air switch or fuse, when the purpose of lightning protection lightning protection device breakdown due to power failure or damage due to lightning damage in time off the link between the device and power supply, lightning protection devices to be failure to repair or replace, the protection of air and then switch reset or replace the blown fuse, lightning protection devices to restore standby.
To ensure a reliable short-circuit protection device onset, generally C-selected before installation of lightning protection device rated current is 32A (C class trip curve) of the air switch, B-level option before the SPD 63A of the rated current value of approximately air switch.
Second, the grounding system of the installation and construction
1, the grounding of the burial.
Room during the distribution infrastructure and solar cell matrix based construction,choose one in the vicinity of underground distribution Fan is no pipeline, no drains, soil thick, wet open ground, the word order dig diameter 1m,2m deep pit 2 to 3 (of which 1 or 2 pits for burial ground of protection of electrical equipment grounding, another pit for a separate burial ground of the grounding rod),pit and pit spacing should be no small at 3m. The pit into the dedicated grounding, ground should be placed vertically in the pit off the center of the top minimum height from the ground should be more than equal to 0.7m,will be placed before the first deflectors and reliable grounding connection.
After the grounding into the pit,filling in the ground around specific reducing agent, until the basic body of the burial ground. Filling process should also inject some water to the pit, so reducing agent to fully take effect.Finally, the original soil to fill the entire real pit. Appliances,equipment protection ground wire deflectors best cross-sectional area 35 mm2 using dedicated multi-strand copper ground cable, lightning rod of 8 mm diameter round steel deflectors can be connected.
2, lightning rod installation.
Installation of lightning rod attached to the best room in the building next to the power distribution,to facilitate the installation of fixed,and as far as laying the ground near the body.Lightning rod of height according to the scope of protection may be,as far as possible the conditions to allow a separate ground.