Solar On-Grid system

Here is how Solar Rooftop On-grid system work:

Photovoltaic comprises the technology to convert sunlight directly into electricity. The term “photo” means light and “voltaic,” electricity. A photovoltaic (PV) cell, also known as “solar cell,” is a semiconductor device that generates electricity when light falls on it. Since its first commercial use in powering orbital satellites of the US space programs in the 1950s, PV has made significant progress with total photovoltaic module industry growing at more than 40% in the past decade.

The PV modules combined with a set of additional application-dependent system components (e.g. inverters, batteries, electrical components, and mounting systems), form a PV system. These PV systems are highly modular, i.e. modules can be linked together to provide power ranging from a few watts to tens of megawatts (MW).

The solar PV panels typically produce DC electricity that is fed to a grid interactive inverter, which in turn converts the DC electricity into AC electricity at a required voltage level. In order to achieve a higher system voltage, the output of inverters is fed to step up transformers to increase the voltage levels at the desired level. From the transformer, the power is routed through the high voltage panel and eventually to other required measuring & protection devices before connecting to the grid. The major equipment and components of a typical solar plant are shown in the following figure.

Photovoltaic Technologies

Multi-Crystalline Silicon

Multi-crystalline (or poly-crystal) silicon panels are made by using polycrystalline wafers. Multi crystalline wafers consists of number of crystallites with different grain sizes will be having grain boundaries and several defects. Multi-crystalline Si growth is relatively cheaper than the mono crystalline Si and the cells made up of these wafers are relatively cheaper. Due to the less pure crystals, the efficiency of these cells reduces and the module efficiencies typically range in between 14-16%. The lifetime of these modules is also around 25 years or more and these panels are cheaper option where the space is not a limitation. These panels are commonly preferred ones for grid connected applications.

Mono PERC & Mono PERC HC

Solar Panels for Commercial and Utility-scale Projects. With a technology that combines rear wafer surface passivation and local rear contacts to maximize light capture, mono PERC solar modules are paving the way for dramatically increased PV system efficiency.

Half-cut cell mono PERC solar modules have solar cells that are cut in half, which improves the solar module's performance and durability. When solar cells are halved, their current is also halved, so resistive losses are lowered and the solar cells can produce more power

PV Technology Recommendation

Each of the above technologies has their own particular strengths and limitations. Multi crystalline silicon photovoltaic technology is recommended for the project on the grounds of easy availability, cost effectiveness and technological stability.

Balance of Plant Systems (BoS)

For a solar PV Plant, the BoS comprises of inverters, cables, mounting structures, foundations and power electronics. Often assigned secondary importance irrespective of their being a significant cost component, BoS are critical determinants of the actual plant life. High technical standards of BoS components should therefore be ensured as a matter of standard practice.

Solar Inverter:

Inverters used here will most likely produce a 1-phase or 3-phase AC with 2nd generation technologies for high efficiency & Reliability with week light generation technology to harvest more power during low radiation with Wi-Fi inbuilt technology for remote monitoring of all parameters on Phone or PC. Polycab provides reverse feeding controller for DG & Reverse flow

Synchronization:

Synchronization achieved at inverter output. Inverter checks for AC output Voltage, Frequency & Phase Sequence against grid parameters at 415 V. When the Inverter AC output matches with grid reference, inverter will close the circuit and start feeding power to the Grid.

Power Evacuation:

DC power generated is converted to AC by inverter and connected to existing Distribution Panel Board at 415 Voltage

Cables

Polycab India Limited is No.1 Company in Cable industry with decades of experience we developed solar cables to meet solar energy requirements Solar cables are flexible and resistant to abrasion and moisture We design the cable as per specification The size of the cables between array interconnections, array to junction boxes, junction boxes to inverter etc is so selected to keep the voltage drop and losses to the minimum. AC cables are solar rated and suitable for the interconnection of the various elements of PV systems

Module Mounting System:

We hold expertise in supplying Solar Panel Mounting Hardware that is widely used for mounting solar panels.

Static load

A solar panel array will exert a static load on a roof of an additional 10 – 15 kg/m2. In most scenarios, this extra load will not impact the design of a residential building’s frame as the frame will already be designed to withstand a live load of 25 kg/m2.

Wind load

An array of solar panels is subject to uplift or down force wind actions as defined by AS/NZS1170.2. How these forces come into play may vary as different zones of the roof are exposed to different loads. Tilted PV arrays are subject to more pronounced wind forces than flush mounted arrays. In most installation scenarios, uplift forces will dictate the design of solar mounting system and its method of attachment to the building frame.

Roof access:

Solar installation and maintenance personnel need to be able to access the roof, move safely on it and be able to access the solar array from all sides. In residential scenarios, it is recommended to maintain a 1 m gap between the roof edge and the array. Commercial roofs should be provided with safe access points and also feature harness attachments points.

Combiner Box:

The DC Distribution Box and AC Distribution Box enables connection of several strings in parallel. DCDB box having fuses to protect the strings for any abnormal faults and ACDB consist of MCCB and SPD to protect from faults

Earthing System:

The method adopted for system is in accordance with code of practice for earthing IS: 3043. For PV yard and Control room building one main earthing ring will be provided along the power plant periphery connected to required number of earth electrodes. The earthing ring will be laid suitably buried conductor, it will be laid minimum one meter away from PV structure.

The earthing system is designed to ensure effective operation of protective gears in case of earth faults. The total earth resistance at any point of the earthing system shall not be more than one ohm. Earthing system shall be kept electrically separate from the metal work of surface by not connecting to pipes / machinery parts etc. for earth continuity.

Lightning Arrestor:

The lightning protection system is designed to ensure effective protection of equipment, buildings & structures in the event of lightning stroke. The lightning protection system is based on ESE technology (Early Streamer Emission Technology). ESE lightning arrestor is mounted on a GI Pole and connected to earth pit using copper cable. This ESE lightning arrestor protects the surrounding area within 107m radius when placed at a height of 6m. The ESE lightning arrestors are positioned in such a fashion that it protects the entire solar power plant, at The same time; it does not cast shadow on to modules.

We will terminate the evacuation because we need only 415V system and connected directly to Distribution Panel