FIELD OF INVENTION
The field of invention relates to cable loss reduction in a PV installation; more specifically, it is related to arrangement of the PV modules in a PV array and DC cable sizing in order to reduce power losses in the PV installations.
BACKGROUND OF INVENTION
The change in people's lives and the increasing dependency on electrical gadgets and instruments in everyday lives demands more and more electrical energy with passing time. While there are multiple sources of generating electricity, solar energy is considered as the most reliable and an ever-lasting renewable source of energy.
The solar power systems used to convert the solar energy to electrical energy consist of photovoltaic (PV) cells connected together to form a PV module. These modules, collectively forming a PV array, are connected to the inverter via a string monitoring box.
It is noticed that that length of the cable from the PV arrays to the string monitoring box and finally to the inverter affect the transmission of power in the cable. Larger cable lengths result in power losses during transmission.
Most of the times, these losses are observed in solar power systems installed over large and/or industrial areas where the need as well as the consumption of electrical power is large. Power losses in such areas are not desirable.

[006] The existing methods for optimal power transmission are not very effective when it comes to reducing the voltage drop in the transmission cables. They also lack a mechanism to receive optimal power transmission from the PV arrays to the inverter, resulting in reduced utilization of solar power, and unwanted redundancy. Losses in solar power systems also affect the performances of dependent systems adversely. [007] Thus, there is evidently a long-felt need for a method that can efficiently reduce the total power losses in solar systems and improve the performances of dependent systems as well.

OBJECT OF INVENTION
[008] The principal object of the invention is to provide an effective method to reduce
the cable loss in PV installations.
[009] Another object of the invention is to provide a method of sizing of DC cable
between string monitoring box and inverter in order to achieve low cable loss.
[0010] Yet another object of the invention is to provide a method of optimizing number
of PV modules in each PV array depending on sizing of DC cable.
BRIEF DESCRIPTION OF DRAWINGS
[0011] This invention is illustrated in the accompanying drawings, throughout which,
like reference letters indicate corresponding parts in the various figures.
[0012] The embodiments herein will be better understood from the following
description with reference to the drawings, in which:
[0013] Fig. 1 illustrates/depicts formation of PV array by electrically connecting and
arranging multiple PV modules together, as described in any prior art.
[0014] Fig. 2 illustrates/depicts the electrical connection displaying the cables between
the PV arrays and the string monitoring box, and between string monitoring box and the
inverter, in accordance with the present invention.
[0015] Fig. 3 illustrates a flowchart elaborating on the process by which power losses
are reduced in the solar power system, in accordance with the present invention.

STATEMENT OF THE INVENTION
[0016] The present invention discloses a system and method of reducing power losses in a Photo Voltaic (PV) installation. The system contains at least one Direct Current (DC) cable in the PV installation, size of the DC cable is calculated based on voltage drop, the derating factor of the DC cable and the short-circuit withstanding capacity of the DC cable. The system further contains multiple photovoltaic modules such that number of the photovoltaic modules in each photovoltaic array of the PV installation is gradually increased with the increase in the size of the DC cable when calculated from the string monitoring box.

DETAILED DESCRIPTION OF THE INVENTION
[0017] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and / or detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0018] The embodiments herein below provide a system and method of reducing power losses in the DC cables which transmit the electrical power generated in PV installations to the inverter. The disclosed system involves optimization of length of the DC cable between the string monitoring box and the inverter, which also helps in optimizing the number of photovoltaic modules in a photovoltaic array. The optimization is done while considering the derating factor, the short circuit withstanding capacity of the cable and the voltage drop for the cable.
[0019] In the scope of the present invention, derating factor may be understood as the factor by which the derating of the cable occurs, where derating means the operation of the cable at a lesser capacity than the value at which it is rated in order to prolong its utility.

[0020] In the scope of the present invention, a photovoltaic cell, hereby referred to as a PV cell, is an electronic device capable of converting light into electrical energy using the photovoltaic effect. The photovoltaic effect is a phenomenon in which electric current and voltage is generated in a device due to the exposure to light. A PV module is built by electrically connecting multiple PV cells. These PV modules are then connected together to form the PV array.
[0021] In the context of the present invention, DC cable sizing may be referred to as the length of the cable between the string monitoring box and the inverter in a PV installation. It is understood from existing prior arts that a string monitoring box is an electronic device where a multitude of strings emerging out of PV arrays combine into a single output cable.
[0022] To begin with, the present invention talks about a system and method of reducing power losses in the DC cables utilized for transmission of electrical power in a PV installation. This is achieved by optimizing the DC cable sizing and gradually increasing the number of PV modules in an individual array as the distance between the string monitoring box and the inverter increases, where the cable is used for power transmission from string monitoring box to the inverter as per the requirement in the PV installations.
[0023] In any PV installation, the length of the cable connecting the string monitoring box to the inverter affects the transmission of power in the cable, where, more the length of the cable, more the power losses occurring in the cable.However, the present

invention addresses this issue in a systematic manner, which is described in the
embodiments below.
[0024] Referring now to the drawings, where similar reference characters denote
corresponding features consistently throughout the figures, there are shown preferred
embodiments.
[0025] Fig. 1 depicts the formation 100 of PV array by electrically connecting and
arranging multiple PV modules together and PV modules by electrically connecting
multiple PV cells, as described in any prior art.
[0026] Multiple individual PV modules 102 are arranged together and connected
electrically to form a PV array 103. The PV modules 102 are electrically connected in a
series connection, irrespective of whether they are placed serially or in a parallel manner
in the PV array 103.
[0027] A person skilled in the art will realize that the connections are wired and the
wires are made up of conducting materials like copper or aluminium. The cables can be
solid or stranded and are covered in insulation to protect them from external factors like
heat, moisture, etc.
[0028] The PV installation, thus created by a systematic arrangement of the PV arrays
103, receives sunlight and converts this light energy/power into electrical power. The
generated electrical power can be used for multiple industrial and domestic purposes.
[0029] The PV arrays 103 transmit the electrical power to the inverter 202 via the
aforementioned wired connection through the string monitoring box 201. It is noticed
that larger the distance between the inverter 202 and the PV arrays 103, more the power

losses incurred in the transmission of the electrical power. The corresponding wires of every PV array 103 combine in the respective string monitoring box 201, the output of which is later fed to an inverter 202.
[0030] Fig. 2 depicts the electrical connection 200 displaying the cables between the PV arrays and the string monitoring box, and between string monitoring box and the inverter, in accordance with the present invention. It consists of an arrangement of PV arrays 103, the string monitoring box 201, the inverter 202 further connected to loads 203.
[0031] The outputs of a certain ‘n’ number of PV arrays 103 in the said arrangement are combined together in a string monitoring box 202, the single output of which is fed to the inverter 203. In a preferred embodiment, there may be multiple such arrangements of PV arrays and string monitoring boxes together constituting the PV installation.There may be multiple string monitoring boxes from each of which the inverter may receive the input individually.
[0032] In one embodiment, the string monitoring box may also be used to provide over-current and over-voltage protection, enhancing the inverter protection. [0033] The consolidated feed of the arrays 103 is sent out to the inverter 202 through the string monitoring box 202. The electric power generated in the PV arrays 103 is a DC supply, and the inverter 202 converts this power into an AC supply. [0034] The transmission of the electrical power generated in the PV arrays 103 occurs from the string monitoring box 202 to the inverter 203 via the conducting metal wires as aforementioned. However, the transmitted power to the inverter 202 is less than the

power generated from the PV arrays 103 due to losses. PV installations built over a large area tend to have a larger distance from the string monitoring box 201 to the inverter 202.The longer distance result in some power being lost during transmission. To reduce the power losses, the optimal cable length is calculated based on various factors such as the voltage drop, the derating factor of the cable and the short-circuit withstanding capacity of the cable.The optimal cable length thus derived influences the number of PV modules to be added in each PV array, and hence contributes towards minimizing the cable loss.
[0035] The losses incurred in the cables may be of various kinds such as, but not limited to, resistive loss i.e. the loss arising due to the resistance in the cable, dielectric loss i.e. the losses incurred due to the dissipation of energy due to the movement of charges in an alternating electromagnetic field as polarisation switches direction, radiated loss, and the kind.
[0036] In one embodiment, the percentage voltage drop may be calculated using the formula:
(2 * Full Load Current * Length of the Cable * Conductor Resistance) x 100 [0037] As the distance between the string monitoring box 201 and the inverter202 increases, the number of PV modules 102 in the array also gradually increase.In one embodiment, with the addition of each module in the PV array, the cable losses decrease up to, approximately, 5%.
[0038] Fig. 3 illustrates a flowchart elaborating on the method implemented for reduction in cable losses in PV installation. The optimal cable length between the string

monitoring box and the inverter is calculated in a way that it results in minimal power losses 301. Further, depending on the optimal cable length, number of PV modules in each PV array in the PV installation is also optimized in a way that results in less cable loss 302. This arrangement successfully reduces the voltage drop or the power losses incurred in the system 303.
[0039] The reduction in the voltage drop results in adequate electrical power being transmitted to the inverter without significant losses.
[0040] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described here.

CLAIMS
We claim,
1. A system of reducing power losses in a Photo Voltaic (PV) installation, the system
comprising:
at least one Direct Current (DC) cable in the PV installation characterized in that the size of the DC cable is calculated based on voltage drop, the derating factor of the DC cable and the short-circuit withstanding capacity of the DC cable ; and
multiple photovoltaic modules characterized in that number of the photovoltaic modules in each photovoltaic array of the PV installation are gradually increased with the increase in the size of the DC cable when calculated from the string monitoring box.
2. The system as claimed in claim 1 wherein the DC cable is connected between a string monitoring box and an inverter in the PV installation.
3. The system as claimed in claim 1 further comprising the percentage voltage drop for calculation of size of the DC cable may be calculated using the formula:
(2 * Full Load Current * Length of the Cable * Conductor Resistance) x 100.
4. A method of reducing power losses in a Photo Voltaic (PV) installation, the method
comprising:

sizing of at least one Direct Current (DC) cable in the PV installation characterized in that the size of the DC cable is calculated based on voltage drop, the derating factor of the DC cable and the short-circuit withstanding capacity of the DC cable; and
optimizing multiple photovoltaic modules in each photovoltaic array of the PV installation characterized in that number of the photovoltaic modules in each photovoltaic array of the PV installation are gradually increased with the increase in the size of the DC cable when calculated from the string monitoring box.
5. The method as claimed in claim 4 wherein the DC cable connecting a string monitoring box and an inverter in the PV installation.
6. The method as claimed in claim 4 further comprising calculating the percentage voltage drop using the formula: