Solar has been one of the most preferred options to mitigate dependence on the conventional source of energy and has gained importance as one of the most suited sources of the decentralized source of energy apart from the wind. The primary reason is inexhaustible, easy to install on the free area available on the rooftop and ground within the plant premises considering captive requirements or on large scale under open access policy. The guaranteed life of the solar system is more than 25 years and an effective payback of 3-5 years as per the grid tariff. Solar photovoltaics is an effective system to reduce your electricity bills and many of Industrial consumers are actively adopting solar as 25-30% of fixed cost is of electricity. This means they would be more competitive in the market by reducing the input cost of electricity.
A grid-connected solar PV system is a type of solar power system that is designed to be connected to the electrical grid. This means that the solar panels are installed on a building or property and are connected to the local utility grid.
When solar panels produce electricity, the power is sent to the grid and can be used by anyone connected to it. This is called net metering. If the solar panels produce more electricity than the building or property is using, the excess power is sent back to the grid and the owner is credited for it.
Grid-connected solar PV systems are a popular choice for residential and commercial properties because they can help reduce energy costs and carbon emissions. Additionally, they provide a reliable source of renewable energy that can be used by anyone connected to the grid.
Since most of the projects installed are Grid connect systems, which means there is an active generation and consumption of power at the load end at the same time without any storage it helps to effectively reduce the electricity bills or the net billing. The system is designed to self-synchronize with the incoming grid voltage and frequency ( LT/HT voltage) seamlessly. In some of the cases where the power backup is through DG Genset, a suitable arrangement can be done through an external control system known as DG-PV Controller to synchronize the system.
Designing a solar system needs meticulous planning in terms of understanding the site feasibility, radiation data and load flow studies of the existing plant infrastructure. A perfect south direction is an ideal roof to generate maximum power as the sun movement is towards east to west. However as Industrial roofs are tilted in different directions, which means there is an azimuth of a certain degree on each of the roofs, the generation can be enhanced with design of a suitable structure for an optimum generation. The industrial roof proposed for the solar project should have the strength of taking a load of solar equipment primarily solar modules, walkways and safety equipment. Ideally, as roof which is able to sustain, 35 Kg -40 KG/ MSQ of the load is ideal to install solar system. As some of the roof don’t have adequate strength during construction, additional strengthening can be done in discussion with a structural consultant. A quick way to analyze is to do the STAAD (Structural Analysis and Designing Program) analysis for the roof. This would also evaluate the structural stability in case of high wind zones. The structure should be capable of withstanding a wind speed of 150-180 KMPH as per the site conditions.
As most the solar system are designed a DC bus bar voltage of 1000-1500 volts it also extremely important to a well-engineered system considering the ambient temperature conditions, cable rating calculation and adequate protection on the DC and AC side. Similarly on the AC side the system should have similar kind of adequate projection in the ACDB ( AC Distribution box) with suitable arrangement of disconnector /breaker and surge protection device. Since the system is exposed to the open sky, also adequate protection in terms of earthing for modules and electrical equipment will help to ground the faults in case of cable fault or any possible surge. Lightening protection ESE ( Early streamer type ) is good mechanism to protect the system against lightning.
The system once installed, the power can be injected directly at the LT/HT panels as per the site availability. A suitable provision can be done for a dedicated electrical panel for the Solar system. The energy meter installed at the ACDB ( AC Distribution box) can measure the generated power in the solar system. The data generated from the solar plant can be effectively captured through SCADA ( Supervisory Control and Data acquisition system) or a data logging system through a web portal to keep a track of generation and historical data for further analysis. Through the help of a weather monitoring system installed with the software, the system can also capture the radiation, humidity and wind speed data which can be correlated with the generation.
To facilitate the adoption of solar energy most of the Indian states have fabricated their solar policy and approval procedures.
By: Suvendu Lenka