Monitoring and control of photovoltaic systems is essential for reliable
functioning and maximum yield of any solar electric system. The simplest
monitoring of an inverter can be performed by reading values on display -
display (usually LCD) is part of almost each grid-connected inverter. Most
important inverter and grid related parameters are available on LCD screen in such
case. Values
like PV array power, AC grid power, PV array current are usually available.
For sophisticated monitoring and control purposes environmental data - like
module temperature, ambient temperature, solar radiation, wind speed can also be
data logged, stored and analysed later. Remote control and monitoring
can be performed by various remote connections: analog modem, ISDN, GSM etc.
The most common connection for local/remote control are USB (sometimes even RS232)
for local monitoring, RS485 and powerline for inverter interconnection. For
wireless connection Bluetooth and Wi-Fi are most common used. Additional services
like satellite based monitoring (SPYCE) are also available.
PHOTOVOLTAIC SYSTEMS MONITORING - BASIC FEATURES
Local monitoring
Most simple way to perform local monitoring is display available on inverter or on
inverter control unit. Other possibilities of local monitoring includes monitoring
by local PC via RS232 connection and/or remote display located in living room for
example (connection between inverter and display is usually wireless). The following
parameters can usually be monitored, datalogged and stored in inverter's memory or
external data logger for particular time (up to 1 year usually). Sometimes
additional sensor related units (external or internal) are also required:
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Array voltage
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VDC
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V
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Grid voltage
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VAC
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V
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Array current
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IDC
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A
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Grid current
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IAC
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A
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Array power
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PDC
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W
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Grid power
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PAC
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W
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TABLE 1: Most common inverter/grid monitoring parameters
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Module temperature
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Tmod
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°C
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Ambient temperature
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Tamb
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°C
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Global irradiance [1]
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G
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W/m2
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Global irradiation [2]
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H
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J/m2
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Wind speed
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v
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m/s
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TABLE 2: Most common ambient monitoring parameters
Wireless remote control of SMA inverters with Sunny Beam
and Bluetooth connection (courtesy: SMA)
External units for inverter monitoring. Personal display Fronius (left) and
Sunny Beam, SMA (right)
(courtesy: Fronius, SMA)
Remote monitoring
Remote control and communication between inverters can be realized with
wireless connection (bluetooth or Wi-Fi), trough RS485
interface or via grid (powerline connection) [3]. Distances up to 1200 m represents
no problem, several tenth inverters can be connected in chain and monitored at the
same time. For remote monitoring different ways of communication can be used:
Ethernet, Internet, dial up access, GSM etc. System can send alerts and status
messages to the control center or user. Alerts and system messages can be send by
SMS service, GSM, fax machine etc.
Remote control of SMA inverters trough Internet
(courtesy: SMA)
Remote monitoring of Fronius inverters with iPod
(courtesy: Fronius)
Data logging
Data can be stored in inverters memory or in external units (data loggers).
Different solutions are available on the market. Some producers offer also
additional memory increase or upgrade. Better data loggers offer monitoring
functions (data logging) for various environmental and additional system related
parameters what can give the user detailed overview about the whole system.
Additional parameters that can be monitored are module- and ambient temperature,
solar radiation, solar irradiation, wind speed (hybrid systems), in some cases
also air pressure and air humidity (sophisticated electronic weather station) etc.
Temperature sensors are usually PT100 or PT1000 sensors. Solar radiation is measured
with reference solar cells (Si-mono), analog inputs of the control equipment are
usually standard 4-20 mA or 0-10 V inputs. Digital inputs are also available and
can be used for net-meter/control equipment interconnection.
Public displays
Public displays are widely used not only as public monitoring tool they are used
as promotional or educational purposes as well. Communication between photovoltaic
system and public display is usually realized via RS232 port, some producers offer
also wireless connection. Most common display types are LCD displays, numbers can
clearly be read from distances up to 40 m, depends on number sizes.
Remote monitoring of PV array with public display
(credit: pvresources)
Sattelite monitoring
SPYCE (Satellite Photovoltaic Yield Control & Evaluation) is based on more than ten
years of research by well-known European institutions. The SPYCE methodology was
developed by the EU project PVSAT. Some of SPYCE's features are: Automatic failure
detection and alarm dramatically minimizes any down time. Failures may be detected
before expiry of warranty. No on-site radiation measurements are required. The
SPYCE website allows access to the system's yields, reference values and analyses
at any time. SPYCE is based on the latest EU research results. Data from the latest
generation of weather satellites is employed. Data flow and the web portal are
adaptable to the requirements of different manufacturers of PV systems and
inverters. SPYCE is a service designed and provided by METEOTEST, a Swiss company,
internationally known for its meteorological expertise. METEOTEST is independent of
PV system manufacturers.
Notes
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[1]
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Common term meaning solar irradiance is also solar power.
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[2]
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The unit Wh/m2 (kWh/m2) is often used in technical practise in
Europe. Sometimes also term insolation (incident solar radiation) is used.
Please look for further information and additional symbols in
suggested literature.
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[3]
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Please note that different monitoring equipment and communication
possibilities of different producers are not compatible. For system monitoring
inverters and control equipment of the same producer must be used.
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MONITORING HARDWARE
HW monitoring tools and data loggers
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COMMON-LINK - Das modulare Überwachungssystem von COMMON-LINK ist in der
Lage, sowohl einzelne Generatorstränge als auch die Ausgänge der Wechselrichter zu
kontrollieren. Es arbeitet unabhängig vom Modell der eingesetzten Wechselrichter
und ist daher mit allen Photovoltaik-Anlagen kompatibel.
Web site available in:
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Solo PV Display -
The Solo can stores several years’ worth of data to its SD Card which can then
be uploaded to a graphical web portal. The website shows historical consumption
of the PV array in kwh generated, money earned and carbon saved since the system
was installed.
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Public displays
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RiCo -
RiCo Electronic supplies standardized and individual large
displays for many applications as for example for solar plants, climatic values,
numbers of items, industrial need, paper industry, accident-free days,
commissioning or date/time.
Web site also available in:
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HvG Engineering -
HvG's display units can be designed according to your wishes when it comes
to size and front layout. Different layouts and offer the
possibility to show any other values besides the values from the PV-system
(if technically possible) can be realized.
Web site also available in:
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PV PERFORMANCE EVALUATION TOOLS
pvmonitor - PV Performance Benchmark - A Free Public Service.
PV wizard -
PVwizard is a web portal focused on assisting all solar power owners keep a vigilent watch over the healthy operation of their system. The basic on-demand benchmark calculator is free always.
REMOTE MONITORING SERVICES AND TELEMETRY
Monitoring and telemetry tools
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inAccess Networks - inAccess provides an integrated solution that continuously monitors and controls the equipment of Photovoltaic Plants aiming at the recognition of operation failures, performance measurements, security and access control as well as collection and recording of statistical data and provision of integrated reports. The PV plants can be managed remotely through the internet and the respective portal providing high degree of flexibility and accessibility.
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Sunny Portal -
Sunny Portal is a web service from SMA Solar Technology AG which enables you
to set up personal Sunny Portal web pages, on which you can visualize the data
pertaining to your photovoltaic system. The Sunny Portal also archives this data.
This means that you can access your system data via the Internet from any location
worldwide. Sunny Portal offers a wide range of functions for monitoring and
visualizing of your photovoltaic system.
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GreenPowerMonitor -
GreenPowerMonitor is the all-in-one monitoring solution for grid-connected installations and for off-grid installations.
Web site also available in:
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Logic Energy -
Logic Energy Ltd. specialises in providing monitoring and reporting services via the Internet, principally for the renewable energy industry. Our systems allow remote monitoring of energy systems, reporting and control of failures all via a web browser. Our graphical interface is easy to use and understand and can be accessed from any web-enabled device, such as a mobile phone,
from anywhere in the world.
Web site also available in:
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PVSoft -
Premier produit de Soft4Energy. Logiciel de supervision et d'exploitation dédié
au photovoltaïque, multi-centrales, multi-fabricants et multi-users,
il est distribué en mode SaaS. Il propose non seulement des fonctionnalités
de monitoring des installations industrielles et résidentielles, mais aussi
des fonctionnalités de gestion de maintenance et de diagnostic avancé
(masque, vieillissement, encrassement, etc.).
Web site available in:
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Rbee Solar -
Rbee Solar is a very easy to use PV monitoring system compatible with all kind of PV installation, irrespective of the inverter installed. We provide approved generation meters with wireless communication (GSM/GPRS) abilities to let you monitor all your installations and give a single access to each of your customers. Rbee Solar also compares radiation (sunshine) and production of PV generators without installing a probe (satellite data).
Web site available in:
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One-ID -
Solar ID est une solution de gestion pour les installateurs solaires qui
gére la supervision, la maintenance et le suivi administratif.
Web site available in:
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Solar-Log -
The ideal combination of monitoring device and evaluation platform.
For every plant size, one or 100 plants, private or industrial.
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QANTUM -
QOS ENERGY is an engineering company specialized in performance monitoring
of renewable energy infrastructures and monitoring of efficient energy use
within building and industries. Proposed to integrators, investors, financier
and operators in
renewable energy, our solutions guarantee technical performances (Quality of
Service/QoS) and economical control of investment done.
Web site available in:
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skytron energy -
our systems allow remote monitoring of energy systems, reporting and control of failures
all via a web browser. Graphical interface is easy to use and understand
and can be accessed from any web-enabled device, such as a mobile phone,
from anywhere in the world.
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Solar CyBro -
Solar Plant Supervisory System (SPSS) is complete hardware and software solution for
monitoring and control of solar power plants. Photovoltaic panels and inverters are
selected of different manufacturers, providing the best solution for each plant.
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SunViewer.net™ -
is a Heliotronic's powerful, interactive tool that enables you to view the
performance of your distributed generation systems over the Internet.
In addition to graphing a variety of quantities of interest, SunViewer.net™
allows users to download data in a spreadsheet compatible format for further
analysis.
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WattSure -
Measure and monitor LIVE how solar thermal, photovoltaic systems and wind turbines are
performing along with many other energy sources including mains electricity.
WattSure is an energy management service that provides real time data about the
performance of energy systems in the home or in the wider commercial environment.
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Fat Spaniel Technologies -
Critical Monitoring and Reporting Services for Renewable Energy Systems.
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Remote monitoring portals
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IBC Solar -
monitoring portal offered by IBC Solar.
Web site available in:
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SolarMax Portal -
Monitoring portal of Sputnik Engineering - Solar Max inverters.
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PV SoldeLight -
private owned PV monitoring portal.
Web site available in:
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PV Log -
monitoring portal for PV systems equiped with InterLink® Solardatalogger.
Web site also available in:
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SOURCES AND ADDITIONAL INFORMATION
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IEEE 802.11,
IEEE Standard for Information technology — Telecommunications and information
exchange between systems — Local and metropolitan area networks — Specific
requirements — Part 11: Wireless LAN Medium Access Control (MAC) and Physical
Layer (PHY) Specifications.
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Wi-Fi Alliance, global non-profit organization with the goal of driving adoption of a single worldwide standard for high-speed wireless local area networking.
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USB Implementers Forum, is a non-profit corporation founded by the group of companies that developed the Universal Serial Bus specification. The USB-IF was formed to provide a support organization and forum for the advancement and adoption of Universal Serial Bus technology.
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Bluetooth, official Bluetooth® technology web site.
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Lamert Bies's web site with detailed information about
serial communication. Descriptions of RS485, RS422, RS232 ports included.
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