Cabling Constraints in PV Array Architecture: Design, Mathematical Model and Cost Analysis

Abstract

In this paper, cabling constraints of different photovoltaic (PV) configurations is addressed in three steps: 1) a cable selection criterion is developed in accordance with metric system defined by American Wire Gauge (AWG), 2) a mathematical model is designed, which estimates the cable length for any array size, and 3) cost functions are devised owing to estimate the cables capital expenditure. The aforementioned steps are developed for Series (S), Parallel (P), Series-Parallel (SP), Total-cross-tied (TCT), Bridge-Link (BL) and HoneyComb (HC). A comprehensive mathematical model is developed for each of the above mentioned architectures in the context of cabling cost versus energy payback time. This cost analysis provides a clear snapshot to the designers of PV plant about the capital investments of cabling system of specific architecture and its potential energy payback time. At the end, a design example for each configuration is presented against an array size of 10×2 PV panels. INDEX TERMS Series-parallel (SP); Bridge-Linked (BL); HoneyComb (HC); Total Cross tied (TCT), Cabling Constraints, Cost Analysis NOMENCLATURE WM Width of module LM Length of module BL Base Length RSP Distance of row spacing ISC Short Circuit Current of PV Module L MM Cable length between two consecutive modules within a string LStr-Str Cable length between two consecutive strings LCab(M_M) Total cable length for module-to-module LCab(Str-Str) Total cable length for string-to-string L RT Extra round trip of cable length to reach inverter θ1 PV Tilt Angle θ2 Solar Elevation Angle NM Number of Modules in a String Nstr Number of Strings in an Array NHC No of Inter Strings Connection in Honey Comb Array IM_M Module-to-module current IStr-Str String-to-string current TCF Temp. Correction Factor TH Highest temperature of installation field (−) Rated current module-to-module (−) Rated current module-to-module CCab(M-M) Cost of cable module-to-module CCab(Str-Str) Cost of cable string-to-string CTotal Total cost of cabling This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.

Implicit Mathematical Model of Photovoltaic Arrays with Improved Calculation Speed Based on Inflection Points of the Current–Voltage Curves

“…The system of nonlinear and implicit equations that describes the electrical behavior of string j at k-th IP is introduced in Equation ( 11), where the first n − 1 equations correspond to the implicit equations of the PV modules in the string (except module k), while the last equation is obtained by applying the Kirchhoff voltage law (KVL) to the string considering the definition of V n+1,j given in Equation (10). In expression (11), V m,k,j is an (n − 1) × 1 vector with the modules voltages (except V k,j ), and V a,k,j is the array voltage for the k-th IP.…”

“…Then, solving expression (11) for the n modules of the string j enables one to construct an n × 1 vector (V aIP,j ) with the array voltages as shown in Equation (13). Such a V aIP,j vector is used in Section 4.1 for the proposed modeling procedure of SP arrays.…”

“…This configuration does not require blocking diodes and, in some cases, mitigates the power reduction produced by non-uniform conditions, which means that not all of the PV modules operate at the same irradiance and temperature and that not all of the PV modules have the same electrical characteristics. However, one disadvantage of TCT arrays is that they require additional wiring [11].…”

DC cable cross-section selection for PV plants

“…This coefficient depends on the type of plant (on the roof, ground, or water) and is given as experimentally determined data. The current capacity is now calculated as [27]…”

Improving the Transient Response of Hybrid Energy Storage System for Voltage Stability in DC Microgrids Using an Autonomous Control Strategy

“…Further, the generated photocurrent, I ph , ideality factor of the diode, µ, shunt resistance, R sh , series resistance, R s and the saturation current, I sat are the five parametric estimation values of the model. Albeit for simplicity, some studies neglect R p [55], [56] or both R p and R s [57].…”