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FUTURE SCADA REQUIREMENTS FOR PV SYSTEMS
Jan Hanno Carstens, Stefan Berg
Solon SE
Am Studio 16, 12489 Berlin, Germany, Tel.: +49 (0) 30 81879 0,
[email protected]
ABSTRACT: Due to size and proportion PV power plants are more
and more in focus regarding their technical
behavior in public grids. As a result Transmission System
Operators are defining new rules for PV farms with respect
to power quality and controllability.
Furthermore, investors of PV plants need to get optimized and
compacted information of their investments.
In addition, service and operators need to get highest remote
control of PV plants.
As a result there are several requirements for future SCADA
(Supervisory Control And Data Acquisition) systems
which differ from todays monitoring systems regarding structure
and complexity.
Keywords: SCADA, Monitoring, Grid Control, Service
1 PURPOSE
In the PV market and its different shareholders there
exists several different requirements for future SCADA
systems which differ from todays monitoring systems
regarding structure and complexity. Content of this
contribution is to summarize requirements from different
views.
2 REQUIREMENTS
2.1 Investors
Investors of PV plants need to get optimized, reliable
and compacted information of their investments. Their
need is a clear visualization of their investments which
isfocused on the commercial status and management ratios.
Visualization of performance ratio and target-
performance comparison should be prepared.
2.2 Service and park operator functionalities
Service and operators need to get highest remote
control of PV plants. Their requirement is to get a status
overview and precise reporting as well as a tool for
detailed remote control and remote failure analysis of the
PV farm devices.
As it is common in e.g. grid operation facilities the
overview of service and park operators needs to have
control room capability all observed stations at one
view with one central login. Alerts need to be
visualized,whereas deeper device access should be possible via
one
mouse click within an intuitive and efficient user
interface.
All in all following requirements have been defined
by service and park operators:
one central login control room capability intuitive and easy
operation browser based information (at user desk no
additional software installation required)
Graphical User Interface (GUI) designed underusability
aspects
required information as PR, weather, power,technical status at a
glance
easy comparison of different PV farms subsidiary park control
remote access from anywhere at any time
bidirectional communication full components control devices
remote data access (converters, DAS,
trackers, weather stations, transformers, )
readability of voltage current, tracker angle,weather, grid
connection status,
remote component control (safety, active andreactive power,
)
high reliability high resistance vs. environmental effects
(wide
temperature range, moisture, )
failsafe easy commissioning central data storage with decentral
data buffer
quick response time automatic event and error report via
Email,
SMS,
secure and safe fast data exchange industrial components
integration of existing PV farms
2.3 Transmission System Operator functionalities
Due to size and proportion PV power plants are more
and more in focus regarding their technical behavior in
public grids. As a result Transmission System Operators
(TSO) are defining new rules for PV farms with respect
to power quality and controllability. These are for
instance the limitation of active power for frequency
control or the control of reactive power for voltageregulation.
In addition, renewable energy plants need to
give contribution to grid stability after grid faults,
usually
named as Fault Ride Trough (FRT).
With more details grid operator requirements
regarding PV farm SCADA properties are:
meeting new grid requirements (e.g. Germany:BDEW-guidelines) to
control solar power plants
active power control reactive power control fault-ride-through
capability standardized and open communication interfaces IEC
61850-7-40 or other communication
protocols to grid operators (optional)
2.4 Project engineering functionalities
To minimize efforts, realization time (time to grid)
and to increase quality as well as reliability during
24th European Photovoltaic Solar Energy Conference, 21-25
September 2009, Hamburg, Germany
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engineering of new power plants it is obvious to use
standardized components and a modular SCADA system.
Project engineering requirements are:
system modularity standardized components used for all
applications (systems and devices with CE aswell as UL certified
components)
flexible SCADA-Topology support of different standard field
buses open for different broadcasting technologies as
wired and wireless (UMTS, Satellite)
easy installation of new components resp.device types
easy integration of new products easy implementation of new
power plants into
data base and GUI
extendable to new requirements and certainly: Low costs
2 REALIZATIONOne possible approach is a realization as shown
in
Figure 1. HMI stands for Human Machine Interface as
computer based GUI as well in the field as also web
based via remote access.
Figure 1: SCADA structure
In this approach each PV farm consists of one PV
farm central Monitoring Connection (CMC) and
optionally different Distributed Monitoring Connection
units (DMC), which connect the CMC to devices as
converters, trackers, weather stations, switchgears,
The Central Monitoring Administration (CMA) is the
central server platform connected to the different PV
farms as well as to the HMI.
TSOs are permitted to connect to the PV farm via
internet using either standardized protocols as e.g. IEC
61850-7-40 or others.
Great importance needs to be attached to the
execution of the HMI/GUI. A state of the art GUI needs
to be intuitive, fast in reaction time, giving the required
information without information overload. And all this
without requiring additional software installation on the
remote computer, means: Required is the use of
conventional browsers installed on each computer.
One approach how a homepage can look like is given
in Figure 2. After login process the user gets an overview
of all observed PV farms in his responsibility. GeneralPV farm
status as well as overall commercial and
technical information are visualized.
Figure 2: GUI example of SCADA homepage
3 SUMMARYThe required investments of PV farms and their
increasing power contribution to the grid cause new
requirements of SCADA systems, different to those
monitoring systems as they have been used since firsthouse
owners needed visualization of their installations.
In particular control of PV farms and its devices by
TSOs or operators require a SCADA solution which
needs to be in hand of system suppliers for being able to
realize and optimize the interactions between operator
commands and devices without making compromises
regarding safety or system stability.
24th European Photovoltaic Solar Energy Conference, 21-25
September 2009, Hamburg, Germany
4292
