Design of 50 MW Grid Connected Solar Power Plant

This paper aimed at developing a convectional procedure for the design of large-scale (50MW) on-grid solar PV systems using the PVSYST Software and AutoCAD. The output of the 50MW grid-connected solar PV system was also simulated using PVsyst software and design of plant layout and Substation to transmit it to 132Kv Busbar using AutoCAD was done with all standard measures. The project began with a collection of databases of various renewable energy systems components from different producers. In this paper the standard procedure developed was affirm in the design of a 50MW grid connected solar PV. This paper contains the different diagrams and single line diagrams that are required for the design of 50MW grid connect solar power plant.


INTRODUCTION
Now day's conventional sources are rapidly depleting. Moreover, the cost of energy is rising and therefore solar energy is one of the most economical and exploitable renewable sources of energy that can be harnessed for generation of power. There are several advantages of using solar energy like low establishment period, no raw material expenses, non-polluting and renewable form of energy, etc. India has very good conditions for the development of photovoltaic solar power systems due mainly the geographical location and it receives solar radiation almost throughout the year, which amounts to 3000 h of sunshine. This is equal to more than 5000 trillion kW h. Almost all parts of India receive 4-7 kW h of solar radiation per sq meters. The country's solar installed capacity reached 34.045 GW as of 31 January 2020. The Indian government had an initial target of 20 GW capacity for 2022, which was achieved four years ahead of schedule. In 2015 the target was raised to 100 GW of solar capacity (including 40 GW from rooftop solar) by 2022, targeting an investment of US$100 billion. India has established nearly 42 solar parks to make land available to the promoters of solar plants. Photovoltaic modules or panels are made of semiconductors that allow sunlight to be converted directly into electricity. These modules can provide you with a safe, reliable, maintenance-free and environmentally friendly source of power for a very long time. A successful implementation of solar PV system involves knowledge on their operational performance under varying climatic condition and also the adequate knowledge of overall plant layout design and design of substation with an appropriate rating of all the equipment used in the plant.

SYSTEM DESIGN AND OBJECTIVE
A study was conducted for optimise Design of 50MW solar power plant considering all Electrical regulation and standards. The general objective in designing a Solar Power Plant to adequately match the capabilities to the load requirements of the consumer, at a minimum cost of the system to the consumer. In order to accomplish this, the designer will need to know the following types of questions about the system.

DESCRIPTION OF SOLAR-PV GRID SYSTEM
Photovoltaic (PV) refers to the direct conversion of sunlight into electrical energy. PV finds application in varying fields such as Off-grid domestic, Off-grid non-domestic, grid connected distributed PV and grid-connected centralised PV. The proposed 50Mw AC is a utility scale grid interactive PV plant.

SOLAR PLANT DC COMPONENTS • Solar PV modules
A PV cell is the principal building block of a solar PV plant. Basically, a semi-conductor, PV cells convert sunlight into useful Direct Current (DC) electrical energy. PV cells are small in size and capable of generating only a few Watts (W) of energy. However, PV plants are highly modular (i.e.) modules can be combined together to generate power ranging from a few watts (W) to tens of megawatts (MW). Due to the electrical properties of PV cells, their manufacturing is restricted to a handful of raw materials. Each material has its unique characteristics which impact PV module performance, manufacturing process and cost. PV cells may be based on either wafer (manufactured by cutting wafers from a solid ingot block of material) or "thin film" material (which is deposited onto low-cost substrates).Module Structures allow PV modules to be securely attached to the ground at a fixed tilt angle, or on sun-tracking frames which orient sun. PV cells can further be characterised according to the long-range structure of the semiconductor material used:

• Inverter
Inverters are solid state electronic devices. They convert DC electricity generated by the PV modules into AC electricity. Inverters can also perform a variety of functions to maximise the output of the plant. These range from optimising the voltage across the strings and monitoring string performance to logging data, and providing protection and isolation in case of irregularities in the grid or with the PV modules. There are two broad classes of inverters:

i) String Inverters ii) Central Inverter
Considering all the losses in inverter from DC to AC, in cables and other transmission losses Solar plant will be designed with 45% overloading of inverter 3.GENERAL LAYOUT AND DESIGN OF DC PART OF 50MW SOLAR PLANT • Before Making layout of the Solar power plant, study and analysis is done of the given land.
• study of the proposed site through satellite images to assess the suitability of the site for development of a 50MWAC solar PV plant is done. Also, by the help of PVsyst software all land analysis and generation prediction are done of the given land.
• Thus, by all the analysis and study it was concluded that for Design of 50Mw Solar plant components to be used are: String Inverter (with 45%overloading) • Array of Module that is a set of Table is of 2x16 • Approximately 250 Acers of land will be used to place a 50Mw Solar power plant.     4.DESIGN OF AC PART OF 50MW SOLAR POWER PLANT Up till now, DC portion of plant was discussed that is up to IDT. After inverting the power from DC to AC power it is to be step up so as to meet the voltage level and frequency of the line grid where the generated power is to be transferred. In AC portion of plant voltage level is quite higher so lots of protecting systems are required. In the power plant most important and costliest equipment is transformer which is to be protected first. Following are the electrical equipment used in the substation for protecting and metering purpose: i. MV Switchgear ii.
Bus-Bar Schemes iii.
Circuit Breakers v.
Instrument Transformers vii.
Earthing System xi.
Lightning Protection

SLD OF 33KV PANEL
Power in IDT after step up to 33Kv it is passed to 33Kv switchgear panel. Here power is pass through the protecting system before transferring to 132kv Substation. Below SLD shows the flow of power in 33kv panel.
In the given panel surge arrester is connected to protect from any short period surge power. Next comes CT for metering and protection. Then circuit breaker is placed to break the circuit in case of fault. Further on PT is placed to measuring and protection. From this power is transferred to main 33Kv panel. 5.2 GENERAL SUBSTATION SLD As discussed above, substation is equipped with the rated and fast responding protection equipment to make the smooth flow of power without any breakdown due to faults.  of converting irradiated solar energy into AC electricity fed into the grid. The losses may be described as a yield loss factor. They are calculated within the PV modelling software and calculated from the cable dimensions. FACTOR (CUF) The Capacity Utilization Factor (CUF) also known as Plant Load Factor (PLF) of a PV power plant (usually expressed as a percentage) is the ratio of the actual output over the period of a year and its output if it had operated at nominal power the entire year, as described in the formula below.

CUF(AC)= Energy Generated per annum (MWh) / (8760 x Installed AC Capacity in MW)
The Year 1 Generation and aggregate CUF (AC) on cumulative project capacity is as below: Year 7. CONCLUSION Hence a study was concluded for 50MW on grid Solar power plant. Concluding the overview of solar plant with all the necessary components of DC as well as for AC. With all this analysis a design of 50MW on grid solar power plant was done using AutoCAD. Designs included the plant layout and all the electrical diagrams with electrical standard measures. Also, using PVsyst software plant efficiency and generation prediction was calculated which comes out to be 80.70% for 1 year. Also, after studying whole plant and its procedure to develop it, some of the research study was done along with this design which can be helpful in future to increase the efficiency of any solar plant. Firstly, using the Black silicon in manufacturing of PV module will increase the module efficiency as black silicon trap and hold maximum solar radiations. And other idea can be implemented in future of Agro Solar plant which include the agriculture of herbs on a cultivated land also can fix solar plant both simultaneously which is said to be Agrosolar plant. Also updating a technology in software used in designing the plant which can reduce man-work and software can calculate and design its own plant design by knowing land coordinates and plant capacity required.