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Energy and Power Engineering, 2013, 5, 474-478
doi:10.4236/epe.2013.54B091 Published Online July 2013 (http://www.scirp.org/journal/epe)
Research on Real-time Data Sharing in Power Integrated
Zhaodong Wang, Xiangjun Liu, Qianqian Wu
North China Electric Power University, School of Electrical and Electronic Engineering, Beijing, Chi na
Email: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org
Received February, 2013
The Power Integrated Automation System has a large amount of the real-time data, it needs to achieve data sharing in
different modules in its own system, sometimes even needs to be shared with the other systems. The thesis discusses the
characteristics and the ways of the real-time data sharing in the first place. Then, it compares the merits and drawbacks
in different ways. Besides, it gives a viable resolution in different aspects, such as the design of the real-time database,
the framework of the communication system and the design of the communication software, as well as the real-time
data sharing in different systems.
Keywords: Power Integrated Automotive Style; Sharing; Real-time Database; DCOM
The measurement, control and the protection of the elec-
tric power system are becoming more and more intelli-
gent and networking, which make the automation of the
converting station become popular and be applied rapidly.
In the general Power Integrated Automation System, it
has a microcomputer monitor protection unit and some
accessory equipment in the comprehensive automotive
system. For example: UPS, VQC devices and so on. These
devices are mostly intelligent, that means they have their
own microcomputer controllers, which can be communi-
cated with the other devices. A full comprehensive auto-
motive system needs to insert all these intelligent de-
vices’ information into the system, in order to make the
data sharing possible. At the same time, the data of the
Power Integrated Automation System needs to upload to
distant dispatch system, MIS system and technological
control system, so as to provide the data to some control
systems, such as dispatch, manage and technological
The data of the Power Integrated Automation System
has many characteristics. It is real-time. The source of
the data is diversified. The formation of the data is com-
plicated. Also, the information of the data is huge. All
these characteristics should be considered when we want
to realize the data sharing.
2. Design of the Real-time Database
The real-time data of the Power Integrated Automation
System includes remote measurement, remote signal,
remote pulse volume, quantity of state, amount of
computation, the events and the faults’ information
delivered by the monitor, the protector and many other
intelligent devices. It includes the commands of manipula-
tion and control, the performance of the command as
well. All these real-time data’s variations require a rapid
reflection of the system. So how to manage the real-time
data effectively is a key problem in the Power Integrated
The Power Integrated Automation System is a
modularization and configuration software system. It is
composed by many packages of software which have
their own functions, and the major packages need to
analysis and process the real-time data in the system.
That is to say, the real-time data can be provided to all
the functional modules in the system, in other words, the
real-time data should be shared among all the modules of
the system. In the developing history of the Power
Integrated Automation System, the ways of the data
sha ring in the system are as follows[2,3].
File sharing. The data input module writes the data
into the files, the inquiry module open and read the file.
In this way, the data files have a specific purpose and a
vivid framework. It is convenient to read and write, and
it is easy for programming. But the speed of reading and
writing is slow. We have to read and write the whole
files every time we refurbish. It is not good for the sys-
tem that has to refurbish frequently.
Direct internal memory visit. We make a sharing
field in the internal memory and promulgate the data
structure to the users, so the users can be accessed to the
Copyright © 2013 SciRes. EPE
Z. D. WANG ET AL. 475
internal memory to get the data. This way has a super
speed, but it is complicated for programming. Even it
will threaten the reliability of the system. Besides, it can
not be visited through the Internet.
Internet communication. We use the TCP/IP or
UDP to pack and send the data. The speed of th is way is
faster than the other ways, but there are binary data in the
data packages, we need to know the data structures, and
it is also complicated for programming. The biggest
shortcoming of this way is not so extensible.
Commercial database. With the development of the
database technology, many databases can provide perfect
data sharing and safety, and open widely. However, in
the automotive system, the real-time data has many
characteristics that are not fit for storage in the commercial
data base, such as the data has an instantaneous effec-
tiveness, the refurbish speed is fast, and the data forms
are disunity and so on.
Internal memory data base. Considering the features
of the real-time data in automotive system, many manu-
facturers have made the internal database used as the
real-time database come true. All the data are stored in
the internal memory, and the structure is flexible, the
visit speed is also very fast. But in consideration with its
openness, it is not as good as the commercial data base.
According to the analysis of the above modes, we can
see that it is a good choice to use the internal memory
data base if we want to meet the need of the real-time of
the Power Integrated Automation System. At the same
time, in order to realize the open, steady data base, we
need to provide standardized interfaces. After anatomiz-
ing, the thesis uses the DCOM technology to realize the
interface visit of the internal memory data base.
COM is a subassembly standard of the Microsoft. It is
an object model made up with component as the units,
and it makes all kinds of software components have an
interactive communication by one agreed mode. On one
hand, the COM provides the interactive norms. On the
other hand, it provides the interactive environment. The
norms are not depended on any specially appointed
languages, so COM is also a standard for different
languages cooperated with each other to develop. DCOM
is the extension of the COM. It can support mutual
communication among different computers between the
components and the client programmes, and these
computers can be linked by WAN, LAN, even the
Internet. As for client programmes, the locations of the
component programmes are transparent, so there is no
need to code for the remote process. By this token, it is
perfect to choose DCOM technology to realize the real-
time data sharing in the Power Integrated Automation
Considering all the factors, the design plan for the
real-time database of the Power Integrated Automation
System is provided. The real-time data are put in the
internal memory with a differential form. As for the
distribution of the internal memory, the real-time data are
not belong to any application, it is used as an independent
real-time data base to provide d igital services to the other
applications. As for the realization of the client, the
DCOM technology is selected to develop the intermediate
layer of the database. In this way, we can ensure the
security of the rea l-time da ta, and also s tand ard the interface
to realize the distributed sharing. When all the modules
visit the real-time data, they all need to use the unified
intermediate layer’s components of the real-time data, so
as to visit and operate the real-time data (including add-
ing, revising, deleting and so on). At the same time, we
need to testify the powers of the applications in the
intermediate layer, so as to keep the data' security. The
intermediate layer provides the ability of visiting the
Internet. It is fit for the internet applications, and in this
way can realize the data' distributed sharing.
The design of the real-time data base and its interface
are showed as Figure 1. The DCOM components in the
intermediate layer have already realized and applied in
the Power Integrated Au to mation System in a larg e scale.
The mode can meet the requirements of the data' real-
time and open sharing features, and the application ef-
fects are very ideal.
3. Input and Output of the Real-time Data
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paragraph. Do not add any kind of pagination anywhere
in the paper. Do not number text heads—the template
will do that for you. In the Power Integrated Automation
System, the real-time data communicates with the intel-
ligent devices. By this way the data can input in the sys-
tems or output to the distant dispatch systems. The input
and the output of the real-time data base is the project to
solve the communicatio n problems with the devices.
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Figure 1. Real –time database and interface.
Copyright © 2013 SciRes. EPE
Z. D. WANG ET AL.
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3.1. Design of the Communication Structure
The host can communicate with the intelligent devices
and get the data of the devices when link the intelligent
devices and the computers with wires. The topological
structure is star class structure. Its visit speed is fast, and
the mode is flexible. The communication interface is the
combination of the RS485 and Ethernet interface. The
RS485 has highly reliability, and the communicate dis-
tance is longer than one kilometre. Besides, the topo-
logical structure can use the bus structure, which means
in one wire we can link many devices with the RS485
interfaces. Recently, with the development of the tech-
nology, many intelligent devices have the internet inter-
faces, and the communicate medias are twisted pair
(RJ45 interface) or optical fibre (fibre-optical interface).
The Ethernet interface for communication has many ad-
vantages, such as the high speed, the large data, and the
communication is steady and reliable. So it is the ten-
dency to use the Ethernet interface for communication in
the Power Integrated Automation System. Our country
made a standard agreement for the communication of the
electrical equipment. There are two main parts: the CDT
and the pooling. The agreement is the gather communi-
cate experience during these years. The design is precise
and reliable, and it is app lied widely into the Power Inte-
grated Automation System. Almost all the complex
automotive factories provide the interfaces for the stan-
3.2. Communication Solution
According to the situation above, we should design a
special subsystem in the Power Integrated Automation
System, so as to communicate with the other intelligent
equipment. The structure is showed as Figure 2.
There designs a special computer for communication,
it collects data from the intelligent equipment and
transmits them into the Power Integrated Automation
System. If there is not so many intelligent equipments
insert, we can use the data acquisition unit of the system
to replace it. We use the server, and use the Ethernet
interface instead of RS485. The host links to the con-
centrator and the switchboard. The topological structure
is mainly used in the star class, and the part uses the bus
structure. The communication wires with the Ethernet
use the super 5 lines, and the other use the industrial
shield twisted pair.
The solution is very convenient for connection, its
configuration is flexible, and it is easy for expansion.
Besides, when you add new intelligent equipments or
upgrade the former equipments, it equals to adding or
revising the nodes of the systems, and it has no impact on
the integral structure of the system.
Multiport serial servers
Network witch and
Figure 2. Structure of communication subsystem.
Z. D. WANG ET AL. 477
3.3. Design of the Communication Software
There are so many communication modes and agree-
ments for the intelligent equipments, many factories es-
tablished the “agreement base” to solve the problems.
They made a special communication module for each
mode and agreement, so as to reuse them. But consider-
ing the actual application effect, the number of the mod-
ules in the “agreement base” is becoming larger and lar-
ger, because many factories use the off standard agree-
ments. And the purpose to reuse is failed, the repeating
work gains too. It is a waste of labour. Considering all
the situations above, we design a three-layer-software for
communication, including communication layer, protocol
layer and application layer. The design is shown as Fig-
The communication layer packages many working
details of the normal communication interfaces, such as
reading and writing, linking, setting up parameters,
dealing with errors and so on. Also the layers above the
communication layer don’t need to care about using what
kind of interfaces. That is to say, the design realizes the
irrelevant among the equipments.
The protocol layer is in charge of organization and in-
terpretation of the data. It is a translation machine to
open and translate the data packets transfer from the
communication layer, and transmits the data to the ap-
plication layer. All the agreements can be into the two
main types: CDT (Central Daylight Time) and Polling. It
is also the most complicated part of the three-layer-
software for communication, especially in dealing with
the off standard agreements.
The application layer manages the communication
procedure with the intelligent equipments. Besides, it
transmits the processing data to the real-time database
and displays the data.
The design of the three-layer-structure divides com-
munication process into three segments, pick up the
common characteristics from different communication
ways, and it simplify the realization of the process. All
the modules in the structure use the interface norms of the
DCOM from the Microsoft and design each interchangeable
process into a DCOM interface.
Figure 3. The communication software structure.
Take the Polling as an example, according to the de-
sign idea of the DCOM interface, we make rules for the
realization of the standard process and each key point,
and define the interfaces shown as Table 1.
The process of the Polling can be described like the
following: loop detection-Listener response-data-Error
retransmission-process data-repetitive execution.
The three-layer-structure realizes the DCOM interface,
normalizes the process and makes sure for the safety of
the communication process. It also increases the reusing,
decreases the repeated labour. It makes the production of
the communication software into a package mode just
like building blocks.
As the producing tasks becoming larger and larger, the
kinds of the intelligent equipments increasing, this me-
thod has a lot of advantages. It is easy for batch produ-
tion. It saves the debugging time with the intelligent
equipments, and increases the w o r king efficiency.
4. Sharing of the Real-time Data in Different
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After using the DCOM technology to package the in-
terface of visiting the real-time database, the real-time
data can get the most convenient and direct way to share
in different systems. Because the DCOM is a standard
interface, if the other systems know the specific details of
the interfaces, they can visit the real-time data just like
the modules in the complex automotive system. Real-
time data includes remote measurement, remote signal
and amount of calculation, operating command, informa-
tion fault and so on. Mean wh ile, the intermediate layer o f
the real-time data base can standardize the interface of
the real-time data, so as to visit and operate the data. Al-
so the intermediate layer adds the function of the certi-
fication authority of application programs, so as to make
sure of the datas’ security. Besides, the intermediate
Table 1. Define the interface.
Loop detection data I Question
Listener response I Listen
Error retransmission I Redo
Test the effectiveness of the data I Check
Failure communication handling I After Error
Process data I data Process
Copyright © 2013 SciRes. EPE
Z. D. WANG ET AL.
Figure 4. Real-time data sharing system.
layer provides the function of visiting the internet, so as
to adjust to the application of the internet, and realizes
the distributed data sharing. In this way, the system can
satisfy the requirements of data’ real-time and open
sharing, and the application effect is perfect. The Figure
4 shows the sharing of the real-time data in the system.
There is a real-time data server for WEB service. It
gets the data of the data base and provid es WEB services.
In this way, any computer linked to it can get access to
the data by the browser, and the relevant works are re-
duced too. All the real-time data of th e complex automo-
tive system, including the data of the intelligent equip-
ments, can be made into pages according to the demands,
and then open to the public. The managers can visit the
working data of the system quickly as long as they link to
the real-time data servers. This is an advantageous way
for management and production.
The research of the paper is sponsored by state key labo-
ratory of alternate electrical power system with renew-
able energy sources. We hereby express our thanks.
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