10 kW Multi Photovoltaic Cell Stand-alone/Grid
Connected System for Office Building
Achitpon Sasitharanuwat 1, Wattanapong Rakwichian2, Nipon Ketjoy 2 and Wuthipong Suponthana3
Physics Program, Faculty of Science, University of Rajabhat Uttaradit, Uttaradit 53000, Thailand
2
School of Renewable Energy Technology, Naresuan University, Phitsanulok 65000, Thailand
3
Leonics Co., Ltd., Bangpakong, Chachoengsao 24180, Thailand
Corresponding author E-Mail: achitpon@yahoo.com
1
Abstract: This paper presents the 10 kW multi photovoltaic (PV) cell stand-alone/grid connected system that supports the energy demand of the Testing Building at the Energy Park of Naresuan University in Thailand. This system is designed and installed based on a
“self sufficient consumption” concept. After a short time for system operation, it is found that each system component and overall system is work effectively. The percentage output powers per watt peak of amorphous thin film, hybrid solar cell and polycrystalline are
102.39, 86.34 and 80.20 respectively. While the efficiency of hybrid solar cell is 13.37, polycrystalline is 10.17 and amorphous thin
film is 6.59.
Key Words: Multi Photovoltaic, Stand-alone/Grid connected system.
1 Introduction
A 10 kW photovoltaic power system is a part of the energy park inside the School of Renewable Energy Technology
of Naresuan University in Thailand. This power system is designed and installed to study and research of each component
and the overall system efficiency and performance [1]. The
basically system design is standalone power system and used
of grid connected to support to ensure the stability and reliability of the system. The main concept of the system is designed based on “Self Sufficient Consumption” that mean the
PV power system (functional as standalone system) will be
balanced and managed the supply side and the demand side
before grid power used, Another interesting in this power system is the different type of PV generator which purposed to
compare the efficiency of each type for short and long term.
2 System design and Components
The system is designed under three main concepts. First,
if solar energy is sufficient to generate the electricity and supplies directly to the load, the excess energy will be charged to
the battery; but if the solar energy is inadequate, the battery
will be discharged to supply the load. Secondly, if the solar
energy and the battery are insufficient, the system will switch
to use the energy from the grid, and when the solar energy and
battery are adequate to supply the load again, it will revert to
the PV generator. In the third case, if the battery is full and
there is no load demand, all the electricity generated from the
system will be fed to the grid.
The three main parts of the system components are the
PV generator, the power conditioning and the energy storage
system. The PV generator is consisted of three different types
of PV technology. Firstly, amorphous thin film (a-si) 3,672 W
of Kaneka CEA 54 W × 68 modules. Secondly, polycrystalline solar cell (p-si) 3,600 W of Sharp NE-80E2E 80 W × 45
modules and the last is hybrid solar cell 2,880 W of Sanyo
HIP-180N1-BO-01 180 W × 16 modules. The total PV power
is 10.152 kW. The power conditioning system is consisted of
three grid connected inverters, 3.5 kW each, Leonics G-304
and three bi-directional inverters, 3.5 kW each, Leonics S218C. The energy storage system is 100 kWh battery, Fiamm
SGM 2000 (16 OPzV) 2 V 2000 Ah x 24 cell. The system
schematic is illustrated in Fig.1.
3 Monitoring System
The PV system is fully monitored to assess the potential
of PV technology and performance of the system. The monitoring system was designed to meet guideline of standard IEC
61724 [2] and within the framework of the International Energy Agency Photovoltaic (IEA PVPS) Program Task 2 [3].
The system parameters which are measured as shown in Tab.1.
Tab.1 The monitored parameters
Electrical parameter
Meteorological
DC,AC voltage PV array 1,2,3
Global irradiance
DC,AC current PV array 1,2,3
Total irradiance
Power PV array 1,2,3
Cell temperature
DC voltage battery
Ambient temperature
DC current battery
Wind speed
DC power battery
Grid voltage & current
Active grid power
Reactive grid power
Energy from and into grid
frequency
P V = A morphous
(K aneka C E A ) 54Wp
(4 P anels / 1 S tring) x 17
S tring = 3.672 kWp
P ublic G rid L ine
P V =P olycrystalline
(S harp) 80Wp
(15 P anels / 1 S tring) x 3
S tring = 3.6 kWp
J unction
box3
J unction
box2
J unction
box1
P V =Hybrid (S anyo)
180Wp
(8 P anels / 1 S tring) x 2
S tring = 2.88 kWp
D iris AP
3
1
3
S2
L2
B i-directional
Inverter
S -218C
3
S4
1
P ower meter
S6
D iris AP
2
L1
L2
L3
A C L oad
C ontroller
C ontroller
C ontroller
S1
1
2
2
L1
G rid C onnected
Inverter
G -304
G rid C onnected
Inverter
G -304
G rid C onnected
Inverter
G -304
P ower
meter
S
5
S3
B i-directional
Inverter
S -218C
B i-directional
Inverter
S -218C
L3
+
-
B a ttery bank48V
Fig.1 A 10kW multi photovoltaic cell standalone/grid connected system
4 Results and Discussion
This system is completely installed on July 13, 2005. After
a short period of system operation, it is found that the system is
work properly. For a short time data collected that could be
shown is comparison of the PV technology efficiency. As mentioned above, the PV generator consisted of three different types
of PV technology, amorphous thin film, polycrystalline and hybrid solar cell. In each PV array, the same type of PV are connected in each type, also the peak power of each array is quite
different as follow, 3,672 W, 3,600 W and 2,880 W. The daily
operation data collected such as solar irradiance, each PV output
power and each PV modules temperature. By a short time of
system operation, from the beginning, it is found that all PV
type is generated the output power respected to the solar irradiance. One thing is noticed from this short time data is that when
the solar irradiance is increasing nearly to 1,000 W/m2 the amorphous thin film can generate the output power higher than its
watt peak while polycrystalline and hybrid solar cell can not
generate up to its watt peak. Some example data is supported
this notification is at 12.00, where the solar irradiance is 991.87
W/m2, the system parameters are measured and calculated, such
as the output power of each PV type, the output power per watt
peak, the efficiency and their temperatures are shown in Tab.2
and Fig.2.
Fig.2 The output power, Irradiance & Temperature curve
Tab.2 The output power & temperature of each PV type
PV type
Amorphous
thin film
Polycrystalline
Hybrid solar cell
Power
(kW)
Power/Wp
(%)
Efficiency
(%)
Temp.
(ºc)
3.76
102.39
6.59
66.07
2.89
80.20
10.17
66.07
2.49
86.34
13.37
62.85
5 Conclusions
After the 10 kW photovoltaic system is installed and a
short time system operation, it is found that each system component and overall system is work effectively. The percentage
output powers per watt peak of amorphous thin film, hybrid solar cell and polycrystalline, are 102.39, 86.34 and 80.20 respectively. While the efficiency of hybrid solar cell is 13.37, polycrystalline is 10.17 and amorphous thin film is 6.59, these results confirmed the PV module specification of their own company.
Acknowledgments
This project is a part of the Energy Park Project supported
by the Energy Conservation Promotion Fund, the Energy Policy
and Planning Office, and the Ministry of Energy of Thailand.
References
[1]Sasitharanuwat, A. and Rakwichain, W. Photovoltaic for Isolated Office System (PIOS) base on Single-User Mini-Grid at
Energy Park, SERT, Thailand. The 2nd European PV-Hybrid
and Mini-Grid Conference, Kassel, Germany, 25-26 September,
2003
[2]International Standard IEC 61724, Photovoltaic system performance monitoring-guidelines for measurement, Data exchange and analysis.
[3]Ulrike J, Bodo G, et al. Task 2 operational performance of
PV system and subsystem. IEA-PVPS, Report IEA-PVPS T2-01,
2000.