Page 250 - Hybrid-Renewable Energy Systems in Microgrids

Solar–wind hybrid renewable energy system 227

examination of statistics and the persistence structure of the daily dry bulb tempera-
tures and daily total global solar radiation.
Some studies have been reported in the literature [31,32] to derive the TMYs for
different cities. These studies considered different weighting factors of meteorologi-
cal parameters. A local TMY for solar and wind energy application and evaluation
was developed by Yang and Lu [33]. They have also shown that determining proper
weather parameters and their weighting factors are imperious for the development of
the TMYs for different kinds of RES.
Various feasibility and performance studies are reported in the literature to evaluate
the performance of various HRES based on statistical meteorological data as in [34–36].

3 Simulation modelling of HRES components

A standalone hybrid solar–wind system consists of PV arrays, wind turbines, battery
bank, inverter, controller, and other accessory devices and cables. The PV and wind
generators work together to satisfy the load demand. When the energy sources (solar
and wind energy) are ample, the excess generated power will be utilised to charge the
battery bank until it reaches its maximum state of charge (SOC) after satisfying the
load demand. On the other hand, when the energy generated by the sources are insuf-
ficient, the battery will discharge and supply energy to assist the PV array and wind
turbine to cover the load requirements until it reaches its minimum SOC.
The design of hybrid solar–wind system is mainly dependent on the performance of
its individual components. It is important to model the individual components first to
predict the system’s performance and then their combination can be evaluated to meet
the demanding reliability. If the power output prediction from these individual com-
ponents is accurate enough, the subsequent combination will deliver the load demand
at the least cost [10].

3.1 Modelling of photovoltaic system

For the selection of the correct component of an HRES and accurate prediction of its
energy generation, their performance analysis under different operating conditions is
very important. The performance of a crystalline silicon PV module is a dependant
on the PV module material, temperature of PV module and the solar radiance on the
PV module surface [10]. Various studies have been reported in the literature on the
analysis of the environmental factors that influence the PV module/array’s perfor-
mance [37–44].
Researchers presented their findings on the influence of temperature on the param-
eters of silicon photocells. They utilised the results of monocrystalline solar cells and
photodiodes with a large light sensitive area for comparison purpose [38]. In their
study, Nishioka et al [39] analysed the temperature coefficient dependence of sys-
tem performance to estimate the annual output of a PV system in an actual operat-
ing environment. Thus, it is observed that the annual output energy of the PV system
increased about 1% by an improvement of 0.1%/C of the temperature coefficient.