Modernization of the National Wide Dispatch Centers of CADAFE

p
ou
Gr m
ng co
lti s.
su gsa
on .rc
RC ww
w
1
Modernization of the National Wide Dispatch
Centers of CADAFE - Venezuela
R. Pirela, R. Pargas, and R. Céspedes, Senior Member, IEEE
Abstract-- The Compañía Anónima de Administración y
Fomento Eléctrico (CADAFE), is one of the most important
utilities of the Venezuelan electric sector given that it is
responsible for the supply of electricity in the major part of the
national territory. With the aim to improve the service to its
millions of end users, CADAFE designed an ambitious plan to
renovate its National and Regional Dispatch Centers and the data
acquisition system using normalized protocols including the
recently standardized IEC 61850 at the level of remote data
concentrating units interfacing modern Intelligent Electronic
Devices (IEDs). The adopted hierarchical architecture is
presented highlighting the changes made with the purpose of
obtaining the optimal use of the computer resources, the best use
of the more than 6000 Km of optical fiber communications and
the integration with the distribution control systems and with the
commercial and corporate IT platforms. The SCADA platform is
described together with the mechanisms adopted for the
centralized data base maintenance and the functionality that
supports both the analysis and the power system operation. The
paper concludes detailing the expected benefits of the project as
part of the general Program of the Integrated CADAFE
Management Reinforcement.
Index Terms-- SCADA/EMS, Control Centers, Power System
Operation, Hierarchical Control Systems, Data Communication.
T
I. INTRODUCTION
HIS document presents the conceptual design of the
SCADA and Energy Management Systems at high voltage
and Distribution SCADA systems for an integrated operation
or the power system under CADAFE´s responsibility. To this
end a hierarchical architecture is presented incorporating the
various levels that are defined for these systems.
The design has as main objective to allow CADAFE to
warrant the security, quality of supply and economy of the
power system operation. To achieve this goal CADAFE is in
the process of implementing state-of-the art technologically
systems supported by a country wide communication network
mainly using fiber optic links in a ring configuration.
R. Pirela and R. Pargas are with CADAFE, Venezuela and R. Cespedes is
Director of KEMA Inc. for Latin America.
Private
10%
Net assets
US$25000 Million
Public
90%
Fig. 1. CADAFE geographical presence in Venezuela
Fig. 1 shows that CADAFE has a main role among the
public electrical utilities in Venezuela since it is the company
that provides electric energy service in almost 70% of the
territory of Venezuela. CADAFE up to now has been
operating with 6 subsidiaries but a reorganization process will
regroup them in a single legal entity responsible for
generation, transmission and distribution of electrical energy.
CADAFE has in excess of 5 million users and provides
services using a complex network at 400/230/115/34.5/13.8
kV. Complete figures about CADAFE are presented in the
company website www.cadafe.gov.ve.
Approximate figures used for sizing the SCADA needs in
CADAFE are as follows in number of substation and data
points:
p
ou
Gr m
ng co
lti s.
su gsa
on .rc
RC ww
w
2
•
SCADA SIZING
SUBPOWER SYSTEM
STATIONS
NIVEL
I
GENERATION AND
BULK
TRANSMISSION
NATIONAL
DATA
POINTS
40
6000
60
9000
100
20000
300
75000
TRANSSMISION (AT
230 kV OR HIGHER)
II
II
REGIONAL
SUBTRANSSMISION
(AT 115KV)
DISTRIBUTION AT
34.5 OR 13.8kV
DISTRIBUTION
Fig. 2. Sizing of SCADA needs in CADAFE
II. CONCEPTUAL SCADA CONFIGURATION
According to CADAFE needs a top-down conceptual
configuration was developed which is based on five Control
System levels as shown in Fig. 3:
Level II: Central, Occidental and Oriental Regional
Dispatching
• Level III: Distribution Dispatching responsible for the
management of the distribution in each one of their
zones of jurisdiction.
• Level IV: Substation equipment including: Data
Concentrators, RTUs, IEDs and other similar
equipment. This depends on the automation level of
each substation.
All levels are supported by a comprehensive
communication architecture which includes the following
media:
• Fiber Optics mostly in ring configuration
• Digital Power Line Carrier with bandwidths of
typically 64Kbps or higher
• Microwave with Wi-Fi capability.
Given the extensive geographical area served by CADAFE,
the major part of the data links uses a combination of data
communication media. High availability is by design assured
by redundant data communications, where available.
The next sections explain in more details the role assigned
to the control centers at each one of the designed hierarchical
levels.
A. Level 0
This level corresponds to the highest hierarchical level in
the configuration. In Venezuela the supervision and
coordination of the operation at the National Interconnected
System – SIN – is the “Oficina de Operación de Sistemas
Interconnectados – OPSIS” which is the national ISO. OPSIS
operates based on an agreement of the following electrical
entities of Venezuela: CADAFE, EDELCA, EDC and
ENELVEN. OPSIS interchanges data with the CADAFE
National Control Center using the ICCP, IEC 60870-6
standard protocol on top of a TCP/IP network.
At Level 0 the hierarchy includes the CADAFE corporate
IT systems where CADAFE management and other CADAFE
divisions will have mainly user interfaces to receive
information. Also at this level corporate GIS/AM/FM/DMS
system may reside.
Fig. 3. Conceptual Configuration
•
•
Level 0: This level corresponds to the Independent
System Operador of Venezuela, Oasis, and to the
Corporate Coordination of CADAFE. Venezuela has
not yet implemented an open Market structure so that
no Market Operador exists in this design.
Level I: Nacional Control Center and Backup Control
Center at the national level. This last one is supported
by one of the regional Level II control centers as
explained below.
B. Level I
The National Control Center of CADAFE is responsible for
the supervision and coordination of the operation of the
CADAFE power system. This center will orient its tasks to
strategic operation planning of the generation and transmission
systems including:
1. Generation operations planning in order to optimize the
operations of the hydro-thermal resources of CADAFE and
also to optimize energy interchanges with other utilities both
for normal and emergency conditions in coordination with
OPSIS,
2. Economic Dispatch in real-time,
3. Frequency and reserve monitoring in the CADAFE
system,
4. Load Forecast for the entire CADAFE system,
5. Coordination of Bulk Energy Metering
6. Maintenance Coordination of Transmission and
p
ou
Gr m
ng co
lti s.
su gsa
on .rc
RC ww
w
3
Generation facilities
7. Supervision and Operation Coordination of the Main
400kV and 230 kV transmission network.
A full redundant back-up system using the Multisite
functionality explained herein below complements Level I
control centers. The backup function will be assigned to the
Occidente Region given the similar equipment being
implemented for this control center. For this purpose a large
overlap of the main and backup control centers database will
be implemented.
C. Level II
Due to the complexity and size of the power system to be
controlled by CADAFE, three geographic zones for the
operation have been defined, these are: Central, Occidental
and Oriental. Each one of these systems will have an
independent and autonomous SCADA/EMS system supported
by the multisite functionality.
These systems will perform substation data acquisition,
information processing and control functions. Additionally,
they will carry out the coordination with the distribution
dispatches located at Level III.
At this level it is also important to identify the Web
services. These will allow sharing information among the
regional dispatches with the corporate information system of
CADAFE through Internet.
D. Level III
This level corresponds to the distribution dispatches which
will be located in diverse areas of the Central, Occidental and
Oriental dispatches (to be defined according to criteria in
discussion at CADAFE). These systems could be designed
with different functionality depending on the area of assigned
responsibility and be installed with three different approaches:
• Local Distribution Dispatch: It will be located at the
same site of a regional dispatch and will use the same
infrastructure of hardware and software of the associated
regional dispatch. It will have an assigned area of specific
responsibility for distribution management; for example, the
distribution system of Valera (site where the Regional
Occidente Dispatch is located) could be supervised and
managed by a local distribution dispatch located in the same
building with a minimum additional investment.
• Satellite Distribution Dispatch: It will be located at a
remote site but it will be associated to a regional dispatch and
will use its hardware and software infrastructure. This system
will have an assigned area of specific responsibility for the
distribution management; for example, the distribution electric
system of Mérida could be supervised and controlled by a
Satellite Distribution Dispatch associated to the system of the
Occidental regional dispatch, but located in a different site.
Communication support of suitable and reliable bandwidth is
required to implant a satellite dispatch.
• Autonomous Distribution Dispatch: It will have its own
SCADA system with its own platform of hardware and
software, and therefore it will not be associated to any regional
dispatch but will exchange information with the regional
dispatch. This approach will be required for complex
distribution system that may need local operation. The criteria
to define which independent SCADA systems will be
implemented are in the definition process. For the information
exchange between the autonomous distribution dispatch and
the regional dispatch center of its zone, the ICCP protocol
over TCP/IP would be used over the optical fiber network. It
is important to note that the distribution dispatches will count
with local user interfaces of the DMS/GIS functionality.
E. Level IV
This level encompasses all substation equipment related to
control, metering and protection, conventional and automated,
including: data concentrators, remote terminal units and IEDs.
All information gathering processes as well as the
supervisory control execution processes will be made at this
level. There are some possible configurations depending on
the substation voltage level and its location.
• Conventional substations will have a Remote Terminal
Unit (RTU): this include those that do not require a high level
of automation. They will support data gathering of status and
analog values, and the execution of commands using
conventional technology.
• Automated substations in which it is convenient to
integrate protection, control and metering by means of a data
concentrator. The data concentrator allows connecting IEDs
and conventional inputs/outputs simultaneously, providing
some processing capacity and the ability to locally handle
automated functions and data processing. This concentrator
will be connected to a substation LAN, with IEDs connected
directly to the LAN or to the data concentrator. The
integration will take place using network protocols such as
IEC 61850, DNP 3i or IEC 60870-5-104. Some existing IEDs
could be connected via serial DNP 3.0 and Modbus protocols.
• Automated distribution substations: this type of
configuration will be similar to the previous one, but will
additionally count with communications via Wi-Fi.
• Generation plant stations, which must report data from
power units typically above 10 MW capacity to the CADAFE
National Dispatch. These will be of a special nature, since the
implementation of generation management functions will
require substation level equipment to read generation plant
data and to execute adequate commands. The design should
involve the integration of existing and projected plant controls.
III. TECHNICAL OVERVIEW
A. Hardware Configuration
CADAFE is in the process to implement modern open
industry standard SCADA/EMS systems for all the control
centers of Level I and II. Fig. 4 presents the main components
of one of the Control Center Systems of Level II.
p
ou
Gr m
ng co
lti s.
su gsa
on .rc
RC ww
w
4
Fig. 4. Hardware Configuration
The main characteristics of the configuration are as
follows:
• Fully redundant LAN configuration,
• Full redundancy at the server levels for main applications
including Data Base (SDM), Historical Information (HIS),
Inter-control Center Protocol (ICCP), Network Applications
(NA) and Front End for serial communications,
• Communications with substations data concentrators
using high speed data links, typically 2 MB, with the standard
IEC protocol. In addition, the systems will support the DNP
3.0 protocol operating on TCP/IP for this purpose,
• Serial communications will support the DNP3.0 level 2
protocol to communicate with some existing Remote Terminal
Units (RTU). The integration of existing CDC remote terminal
units that will remain as part of the control center
implementation will use protocol converters to one of the
supported
protocols depending on
the available
communication media,
• WEB server to provide access to selected data for “light
users” that will employ a commercial browser for data access.
This may include bulk power consumers in the future,
• Video Display of latest technology for the presentation of
overview data for the dispatchers.
B. Software
A complete suite of SCADA/EMS is at the base of the
control systems software for Levels I and II control centers.
The following describes the Multisite functionality allowing
the implementation of the conceptual system design explained
above.
The Multisite function allows connecting all the Level I
and II control systems of CADAFE to a Multisite network.
The connected control centers register simultaneously process
information and fulfill operation control tasks in the
geographical areas assigned to them, that is Centro, Occidente
and Oriente. In addition the Centro Control System is backed
up by the Occidente System using the Multisite functionality.
Each control center is autonomous and independent in the
Multisite network. A very large data volume will be
distributed by means of Multisite over all Level I and II
control centers to reduce server loading. The control centers
will have similar hardware but different data. However, the
functionality may allow to implement Control Centers with
different hardware and different responsibilities in case for
instance the Multisite functionality is extended to the Level III
control centers.
The Multisite functionality adopted by CADAFE will run
in an environment with the following characteristics:
a) Communication between Control Centers
All control centers of Levels I and II will be connected via
WAN links supporting 100 Mbps in order to allow almost
“local” operation for any operator login into a remote server of
another control center. The control centers will communicate
with each other using the TCP/IP protocol. The physical
connection between the control centers will be redundant
using the ring configurations implemented by the Fiber Optics
projects of CADAFE using OPGW conductors.
b) Control Center Redundancy
Multisite features will enable the implementation of a full
backup of the National Control Center in the Occidente
control center. Besides, the backup of any of the regional
control center will be implemented by having all systems
sharing a common set of data. In this form operators of any of
the regional control centers may perform tasks of another
region providing full support between Level II control
systems. In this case the areas of information of the control
centers will be defined with an appropriate large overlapping
allowing two control centers sharing the operation control
tasks for the same area.
Via Multisite means a control center will be defined with
backup functionality for another control center (main system).
The main system and the backup system are two
autonomous and independent control centers which have
identical data model and the same data volume. Identical
information areas are assigned to both control centers.
The operation control tasks are assigned to the main
system. Main system and backup system are master systems
for the same data points. The main system always has the data
responsibility. The main system is configured as data master
system.
c) Data Maintenance
The data maintenance will be made centrally assigning one
of the centers to be responsible for data dissemination. All
data model modifications are entered at the data model master
and distributed from there to the remaining control centers.
For central data maintenance all control centers will have a
common data model with identical addressing schemes.
The data model modifications are stored intermediately at
each control center. After a connection failure or system runup all intermediately queued up data model modifications are
requested from an appropriate control center and updated in
the data maintenance dependent control center.
All control centers have the complete data model with
formal identical content of information. The physical data
model of the single control centers is known to all other
control centers.
p
ou
Gr m
ng co
lti s.
su gsa
on .rc
RC ww
w
5
d) Delegation of Operation Control Task
The operation control task will be flexible to move
responsibilities between the control centers at the request of
the operation supervisor. This will allow operating a control
center even unmanned during periods when management
requirements are low, which could be the case of future
control centers for electrical energy distribution.
The Multisite network functionality will allow the control
center authority for operation control be defined globally and
with overlapping, if necessary. The user authority and the
console authority are defined locally as required by the local
national or regional operation procedures.
e) Data Transmission
Local data (captured by the local SCADA functions) and
locally calculated values will be made available to other
control centers in the Multisite network. Remote control can
be done by other control centers, in case the authority for
operation control is assigned to that control center.
Manual inputs like process substituted values, updating and
tagging can be entered by the operator with global or local
scope. A local input is only valid for the respective control
center. A global input is effective in the whole Multisite
network.
In case the connection between two control centers fails,
then each control center remains in proper autonomous
operation condition with the restriction, that in this case only a
part of the values may be available, that is, data acquired by
another center with failed communication will not be received
by the others. However the system robustness allows that after
restoration of the connection between the control centers or
after system run-up, the data which are necessary for a defined
initial status are automatically requested and transmitted.
Remote control via the multisite manager is possible at all
control centers, if the operation control task is assigned to the
respective control center.
The commands and setpoints are transmitted to the control
center with data responsibility and executed there. The
controlling system as well as the system to be controlled make
all checks (rights, interlocking conditions, run-time
monitoring).
As acknowledgment the controlling system gets the status
change from the controlled system. In case of “no execution”
because of interlocking conditions, the controlling system
receives an error. Detailed diagnostic report is not transmitted
from the controlled system.
If the connection to the data responsible control center has
failed, commands can not be transferred to this control center.
In this case a diagnostic report is immediately built at the
controlling system. The connection failure to the data
responsible control center after sending a command, will be
realized by the local time monitoring.
Switching procedures are created locally and transmitted
via supervisory control in form of single steps, because several
control centers may be concerned.
Local switching procedures are transmitted in form of
single steps.
IV. HIERACHICAL CONCEPTUAL CONFIGURATION
Figure 5 shows the planned detailed configuration for the
implementation of the control centers at the various levels.
This configuration includes the different control centers
explained above and identifies substation controls for the
various voltage levels.
The following remarks provide some additional details:
1. The equipment highlighted in blue is part of the
implementation of the transmission SCADA systems. They
will provide for the operation of all transmission and
subtransmission substations. These centers will provide the
support of distribution through local and remote user
interfaces where needed.
2. A number, yet in the process of being defined, of satellite
SCADA systems will complement the previous control centers
in order to provide local SCADA functionality for the
operation of the distribution networks.
3. Data Concentrators will be implemented in all
transmission and subtransmission stations requiring the RTU
upgrade allowing collecting data that is presently available
through RTUs and also providing for the integration of local
Intelligent Electronic Devices, IEDs thus supporting the
implementation of substation automation scheme.
4. The IEDs implementation and the implementation of
SCADA at the distribution substations is part of a different
project that is also being implemented by CADAFE.
5. The boxes in Red are related to the protection relays
management which is a future projected function of the
regional dispatch. The management of relays will allow the
remote change of relays settings including for instance
tripping parameters according to the actual network topology.
This management is considered important to provide for
saving time and resources.
V. CONCLUSIONS
This paper presented an overview of the control center
design of CADAFE. The major components of such design are
described in detail. On purpose traditional functionality of
SCADA/EMS systems explained in the technical literature are
omitted.
The main benefits expected form the implementation of
these
control
centers
are
as
follows:
1) Rationalize the expenses of CADAFE in SCADA
technology by utilizing at the maximum possible extend the
projects already at the development stage and the related
communication infrastructure,
2) Provide a solid platform for implementing a National
Control center with the functionality directed to support the
CADAFE strategies for generation, supply of the demand and
selling/purchasing of energy.
3) Support adequately the distribution operation which until
now has been mainly coordinated manually without the
support of real-time data.
p
ou
Gr m
ng co
lti s.
su gsa
on .rc
RC ww
w
6
PP
P
Fig.5. Detailed Control Center Configuration of CADAFE
The presented design provides for a good support of the
CADAFE reorganization and takes advantage of the planned
investments on related projects.
VI. ACKNOWLEDGMENT
The authors thank all CADAFE employees that have
provided information that made possible to complete the
description of the projects that are addressed in this document.
Some of the implementation issues in particular at the
distribution level are at the moment of writing still at the
design level and thus have to be taken as a preliminary
approach and are thus subject to change.
VII. REFERENCES
[1]
[2]
[3]
CADAFE, Modernization of the Central and Occidente Control Center
Systems Specification, 2004.
CADAFE, Distribution SCADA/DMS Automation Project description,
and terms of references, 2005.
SIEMENS A.G. Functional specifications of the CADAFE control
center systems implementation.
VIII. BIOGRAPHIES
Raul Pirela is from Venezuela and is presently Transmission Vice-
president of CADAFE. Raul Pirela is Electrical Engineer and has made
previously a complete career with ENELVEN the utility of Zulia state where
he has held various positions including Vice-president.
Ramón Pargas is from Venezuela and is presently the head of the
Occidente Dispatch center of CADAFE. He is project manager for the
implementation of the new transmission SCADA/EMS platform. Mr. Pargas
holds an electrical engineer diploma and has been with CADAFE at various
positions in the operations divisions.
Renato Cespedes (M76, SM86) is Colombian. He graduated as Electrical
Engineer (1972) at the University of the Andes (Colombia). He obtained a
Ph.D. in Engineering from the National Polytechnique Institute of Grenoble,
France. He is Director Latin America with KEMA Inc.and associate professor
at the National University of Colombia, Bogota.