up to 0.0003°
accuracy with an astronomical algorithm
and SIMATIC S7-1200
www.siemens.com/solar-industry
Simply follow the sun
Maximize the yields of solar power plants with solar tracking control
Answers for industry.
You got to keep
them moving …
Solar tracking control systems by Siemens are based on
SIMATIC S7-1200. They provide an optimal solution for
maximizing
the energy yield of solar power plants.
It goes without saying that solar power
plants need to have their photovoltaic
panels or mirrors aligned perpendicular
or at a certain angle to the sun to operate
at peak efficiency. Panel alignment maximizes energy yields up to 30–40 percent
in cell-based photovoltaics (PV), while
precise alignment is an unconditional
prerequisite for stable and efficient
power generation in concentrated photovoltaics (CPV) and concentrated solar
power (CSP). However, the sun’s position
in the sky is constantly changing.
The innovative and highly efficient
single-axis and dual-axis solar tracking
control system by Siemens can control
the azimuthal and zenithal movements
of PV and CPV panels and CSP mirrors,
constantly correcting their position
and pointing them directly towards the
sun. That’s how the Siemens tracking
control system, which is based on
SIMATIC S7-1200, contributes to a
considerable increase of electricity
generation.
2
Your benefits at a glance:
■■Innovative, highly efficient control
system
■■Based on industry-proven technology
■■Modular design makes the control
system suitable for PV, CPV, and CSP
applications
■■The open interfaces of SIMATIC
S7-1200 support communication with
the solar park‘s other components.
■■Communication with Siemens components is optimized thanks to Totally
Integrated Automation (TIA)
■■Software library supports the integration of several functionalities
■■Flexibly expandable thanks to modular
design
Seamless integration thanks
to TIA and TIA Portal
Benefits of TIA
SIMATIC S7-1200 and TIA Portal
■■Reduced time to market thanks to reduced development
time
The Siemens solar tracking system is based on the
SIMATIC S7-1200 controller, which defines a new dimension in compact automation. It provides highest flexibility
for smart solutions thanks to its scalable hardware and
ensures accurate positioning with its 64-bit resolution.
The controller also has a web server that makes it possible
to access it with a web browser. SIMATIC S7-1200 is fully
integrated in Totally Integrated Automation Portal
(TIA Portal), the innovative engineering framework for all
automation tasks. TIA Portal redefines engineering within
TIA. It improves competitiveness by maximizing the return
on investment for engineering with its intuitive operation,
efficient engineering, and proven functionality.
■■Control components of each application scalable to
individual needs
■■Simplified international deployment of tracking systems
■■Long-term investment security
■■Reduced total cost of ownership
■■Quick, easy, and flexible configuration of tracking
control solutions
■■Reduced commissioning time
3
HEAD
Controller with superordinated task
*
SUB 5
*
…
*
SUB 1
*
SUB 6
*
Field PG for commissioning
…
*
SUB 2
*
SUB 7
*
Communication
…
*
Communication equipment by
Siemens also facilitates the simple
networking between the various
solar tracking controllers, control
and monitoring systems, and
inverters.
SUB 3
*
SUB 8
*
…
*
* SIMATIC S7-1200,
controller for tracking task
SUB 4
*
SUB 9
*
Small-sized solar farm: e.g. up to 25 trackers merged to a single cluster
Applicable for solar farms
of any size
Siemens’ universal tracking control system suits all solar applications from simple single-axis movement in PV applications all the way to highly precise
dual-axis movements in CPV systems.
Each solar tracking unit is perfectly controlled by a SIMATIC S7-1200. A solar
tracking unit can consist of one or several
trackers. The configuration of a park’s
communication system is noticeably
influenced by the location’s geographical
conditions. A practical solution for
smaller parks is the formation of clusters
that are connected in line using
PROFINET. In these cases, a controller
takes over superordinated functions such
as the handling of wind alarms and time
synchronization. In larger parks of more
than 25 trackers, the combination of line
and star connections is a feasible option.
4
In addition, various transmission media,
such as optical fiber, can be used.
SIMATIC S7-1200 software and hardware
are expandable according to individual
requirements. The onboard PROFINET
interface and expansion modules with
communication interfaces, such as
PROFIBUS and Modbus, ensure easy integration into the consistent communication of the entire solar farm.
Park monitoring
central system
HEAD
Controller with
superordinated task
SIMATIC S7-300/400
Internet
SCALANCE X
SUB 1
*
SUB 2
*
SUB 3
*
SUB …
*
SUB …
*
SUB …
*
SUB …
*
SUB …
*
Field PG for commissioning
SUB …
*
SUB …
*
SUB …
*
Single-unit application
The solar tracker control libraries
support solar power plant operators
with several modes (manual, teach,
and auto mode) of operation to
match any application.
SUB …
*
Medium and large-scale solar farms: multiple clusters merged using e.g. SIMATIC S7-300 as HEAD PLC
A SIMATIC solar position library for the
tracking control system is available on
demand. It calculates the general position of the sun for a certain location and
time and controls the positioning of the
solar tracker accordingly. Smart softwarebased features ensure appropriate control in various weather conditions. Precise axial and lateral adjustments are
based on an astronomical algorithm
featuring 64-bit arithmetic accuracy
that even meets the requirements of
CPV systems.
A central, PC-based HMI facilitates realtime status monitoring and control of all
solar trackers.
5
Simple astronomical algorithm
Photovoltaic (PV)
Advanced astronomical algorithm
Concentrated Solar Power (CSP)
Concentrated Photovoltaic (CPV)
Parabolic Trough
Dish-Stirling
Central Receiver Tower
Precise tracking with astronomical algorithm
Siemens tracking controls are designed to operate without sun sensors to ensure maximum availability. A cyclic
astronomical algorithm evaluates the position of the sun
on the basis of a comparison of latitude and longitude
with the UTC time. SIMATIC S7-1200 uses the position of
the sun, defined by azimuth and zenith, to align the panel
perpendicular to the sun.
The accuracy of the simple astronomical algorithm is sufficient for standard photovoltaic, including single- or double-axis PV solar trackers. The advanced astronomical
algorithm SPA that was developed by the National Renewable Energy Laboratory (NREL) for the U.S. Department of
Energy (DOE)* is specified with a cutting-edge accuracy of
+/-0.0003°. This ensures an operational accuracy that is
better than +/- 0.05° including mechanical tolerances if
high precision gears are used. This kind of high precision
astronomical algorithm is required for CPV and CSP solar
tracker applications.
*Neither NREL nor DOE endorse SIMATIC
Both versions of the astronomical algorithm are included
in a library that can be implemented easily in any solar
tracking application. Siemens provides application examples for solar tracking with SIMATIC S7-1200. They are
automation concepts that are pre-developed to suit typical tracking applications. They can be adapted to meet the
most challenging requirements in order to ensure the
highest possible degree of efficiency. The application
examples comprise functions such as wind handling,
which prevents damage to the panels in case of a storm
by positioning the panel horizontally in order to minimize
the wind load. The back tracking function ensures that all
panels are kept from shading each other by adequate
adaptive movements. Peak loads can be avoided with a
function that clusters the solar panels into groups, which
ensure that all solar trackers adjust their alignment
accordingly but not at the same time.
6
Photovoltaic (PV)
Concentrated Photovoltaic (CPV)
Solar
Tracking
Concentrated Solar Power (CSP)
Concentrated Solar Power (CSP)
Parabolic Trough
Dish-Stirling
Concentrated Solar Power (CSP)
Central Receiver Tower
7
Find out more:
siemens.com/glass-solarindustry
Learn more about
how plant-wide
integrated solutions
contribute to
optimize your
energy efficiency,
productivity, time-tomarket and quality.
Plant-wide
integrated
solutions –
take a look!
Subject to change without prior notice
Order No.: E20001-A140-T112-X-7600
Dispo 41513
21/43444 MI.AS.VM.XXSO.52.2.03
WS 08123.
Printed in Germany
© Siemens AG 2012
The information provided in this brochure contains
merely general descriptions or characteristics of
performance which in case of actual use do not
always apply as described or which may change as
a result of further development of the products.
An obligation to provide the respective characteristics shall only exist if expressly agreed in the
terms of contract.
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product names of Siemens AG or supplier com­
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