Effect Of Lightning On Photovoltaic Systems: Mitigation And Protection Techniques

Battery backup time and capacity

Given data from the solution:

The voltage in the OV systems = 12 V

Power of the LED=  8 of 10 W

• Number of batteries
• Ah for the 7 days of autonomy

Load = 10 Watts

Required Backup time for batteries = 12 hrs per day = 0.5 days

Now the required Back up Time of batteries in Hours = 0.5 days

Now for One Battery:

8Wh / 10 W = 8/10 hrs

Therefore, 0.5/ (8/10) = 5/10*(10/8)= 0.8

Answer: Therefore for 7 days, number of batteries needed= 0.8*7= 5.6 or 6 batteries

Further for determining the Ah or battery capacity,

Battery Capacity (Ah) = Total Watt-hours per day used by appliances x Days of autonomy (0.85 x 0.6 x nominal battery voltage

8 Wh*6 batteries = 48 Wh

Answer: 48 Wh/ 10 W= 4.8 hours

The batteries have been accumulating the additional energy developed by the PV system. They have been stored to be used at night or the time when no energy input takes place. They are able to discharge rapidly and yielding more current. This is more than the charging source has been producing by them. Hence the motors could be run intermittently. In the given scenario, the PV system has encompassed a 12 V battery system. This also included a MPPT charge or discharge controller. Further it also comprised of 8 of 10 LED.

The rating has been designed for comparing various batteries to the similar standard. This is not been taken as the performance guarantee. These batteries are the electromagnetic devices that are sensitive to the charge/discharge cycle history, climate, and temperature. The battery’s performance has been relying in the usage patterns, locations and climate. In the given scenario, the battery is removed for every 12 hours.

The PV module is the assembly of the photovoltaic or PV or solar cells. It is an important component of PV systems converting sunlight to DC. Lightning, on the other hand, is a common reason for the failures in the PV and wind-electric systems.

This harmful surge takes place from lightening. Thus there have been various rising concerns regarding the afflicting of lightening on the PV modules. This damages those modules and its nearby components.

The following study demonstrates the effect of this lightning on the solar panels. A suggestion is made regarding the mitigation of the lightning effects.

The photovoltaic systems have been inherently exposed to different direct and indirect lighting effects. The deploying of the solar cell arrays for the high capacity systems needs a high sector with the commensurate exposing towards the direct lightning strikes. This takes place at the local yearly rate of different ground strikes per unit area (Yang et al.). The existence of the ground grid related to the PV system has been an isolated sector acting as the collector of the ground-current of lightning from the nearest strikes. Regarding the PV systems getting tied to local power grids, the exposures also incorporate the surges originating from a power grid and possible differences in the ground potential of AC and DC power systems (Yang et al.).

Effect of Lightning on Solar Panels

For the current development stages of PV systems, the happenings of those lightning strikes are rare. Hence the experience of the field is still restricted. Thus justifiable concerns are there nevertheless. This is both from the financial perspective of the harms verses expenses of protection. This is the less tangible effect on the view-point of reliability for this technology which is still in its initial phases of commercial usages.

Maximum of the electronic and electrical harms in the on off-grid and grid-tie solar electric systems have been not because of the direct hitting. This, in fact, is rare. Maximum of this takes place from the nearest hits, mainly under a hundred feet. The nearby strike induces numerous volts on to PV array wiring as this not gets adequately protected (Guo et al.). This could spread out on the ground hit and travel to the buried conductors like the buried cables and pipes. As contrary to the popular beliefs, the panels have been not the most significant victim. These are the controllers and inverters who get victimized. The mounts and frames on the boards are grounded. This has been many times more due to accident than design. This diverts the lightning to the directly. Thus the solar panels are saved. Moreover, the battery banks on maximum off-grid systems of PV have been acting as the reasonably efficient surge arrestor (Christodoulou et al.). However, this can take out the controller on their way. As the battery bank is never grounded, the harm is much more severe. This might then leap across all the areas seeking to determine the path towards the ground.

The objects could be struck directly, and the impact results in the burning, explosion and complete destruction. Besides this, the harm might be not direct as the current passes by or near that. At many times, the current enters the buildings and then transfer via wires or plumbing (Hernandez et al.). This might also harm all the things in their path. In the same way in the urban sectors, this strikes the tree or poles. Then the current passes to various nearing houses and the additional structures. It enters via plumbing and wiring. In multiple cases, the lightning strikes the ground and travel up the buried power line regarding hundreds of yards.

The various processes to reduce the impacts are discussed below.

Conclusion

The report shows that the organizations insuring solar projects have been increasingly interested in lightning protection. This is especially in the sectors where there is a high probability of the lightning. The study discussed that lightning is a major reason behind the catastrophic failures in the PV systems. The primary elements included in protecting the PV systems are an installation of the surge protective devices and appropriate grounding. Apart from this, the surge protection devices supply the potential of the flow diversion of electricity prior the equipment gets damages through the rising voltage. This could be positioned strategically to deliver a redundancy which is important.

Grounding and NEC requirements

References

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