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Academic Open Internet Journal |
Volume 15, 2005 |
POWER DISTRIBUTION AUTOMATION: PRESENT STATUS
R. P. Gupta and R. K.
Varma
Department
of Electrical and Computer Engineering
Email:
rampg@iitk.ac.in
ABSTRACT:
Electric power distribution system is an important part of electrical power systems in delivery of electricity to consumers. Electric power utilities worldwide are increasingly adopting the computer aided monitoring, control and management of electric power distribution system to provide better services to electric consumers. Therefore, research and development activities worldwide are being carried out to automate the electric power distribution system utilizing recent advancement in the area of Information Technology (IT) and data communication system. This paper reports the present and past status of the research and development activities in the area of electric power distribution automation both in developed as well as in developing countries. The information given in this paper is useful to electric power distribution utilities and academicians involved in research and development activities in the area of power distribution automation.
1. INTRODUCTION
Electric
utilities, all around the world, have realized the problems associated with
vertically integrated electric power systems and therefore they are moving
towards unbundled model of generation companies (GENCOs), transmission
companies (TRANSCOs), distribution companies (DISCOs), and energy service
companies (ESCOs). In the past, all electric power distribution-related
functions could be transparently coordinated along the complete supply chain.
In the future, many distribution companies will manage third-party contacts by
delivering bulk power from GENCOs and TRANSCOs to meters owned by ESCOs.
At the same time, many state regulatory commissions are
considering the viability of retail wheeling (small generators connected to the
distribution system selling electricity directly to customers). In addition to
planning and operating difficulties, retail wheeling asks distribution systems
to perform the functions for which they were not designed [1].
In view of the above, on-line information, remote control and
efficient management system are required for power distribution utilities. Considering
the extensive size of the network, these tasks can be effectively achieved
through the intervention of information technology utilizing the available
high-speed computer and communication technology. This system of monitoring and
control of electric power distribution networks is also called as “Distribution
Automation (DA)” system.
The
DA system is beneficial in day-to-day operation and maintenance of distribution network. The other benefits of the distribution automation are: reduced technical and commercial losses, improved cash flow, lower electric service restoration time, reduction in equipment damage, better availability of system information, improved operational planning, remote load control and shedding, and enhanced power quality and reliability [6].
In view of the importance of the distribution automation, a literature survey work has been carried out to get past and present status of the research and development activities. The outcome of the literature survey work is reported in this paper. On the basis of present and past research status, a list of possible research topics has also been identified and reported in this paper for future research work in the area of power distribution automation. The information given in this paper is useful to electric power distribution utilities and academicians involved in the research and development of the power distribution automation.
2. DISTRIBUTION AUTOMATION: GROWTH AND
CHALLENGES IN
DEVELOPED
COUNTRIES
The idea of distribution automation began in 1970s. The motivation
at that time was to use the evolving computer and communications technology to
improve operating performance of distribution systems. Since then, the growth
of distribution automation has been dictated by the level of sophistication of
existing monitoring, control, and communication technologies; and performance
and cost of available equipment. Although distribution systems are a
significant part of power systems, advances in distribution control technology
have lagged considerably behind advances in generation and transmission control
[7]. Small pilot projects were implemented by a few
utilities to test the concept of distribution automation in the 1970s. In the
1980s, there were several major pilot projects. By the 1990s, the DA technology
had matured and that resulted in several large and many small projects at
various utilities [8],[9],[10],[11].
Some people expected
that most of the utilities would come forward for large-scale distribution
automation. However, many utilities found it difficult to justify distribution
automation based on hard cost-benefit numbers. Business uncertainties due to
deregulation and restructuring of the power industry slowed wide scale
implementation of distribution automation. Thus, it is justified to re-examine
the overall philosophy of distribution automation. Instead of undertaking mega
projects, it is time to “think small”. In other words, instead of a top-down
approach, it is perhaps better for the utilities to opt for the bottom-up approach.
Moreover, selection of distribution automation functions for implementation
should always be need-based [12]. Improvements of system reliability and voltage
profile on the feeders are two examples of the needs for utilities [13],[14]. Need-based automation would be easier to justify and
win approval of the management. Distribution automation also provides many
intangible benefits, which should be given consideration while deciding for
implementation of distribution automation. After the deregulation and
restructuring issues are settled, distribution automation activities should
increase.
Automation
allows utilities to implement flexible control of distribution systems, which
can be used to enhance efficiency, reliability, and quality of electric
service. Flexible control also results in more effective utilization and
life-extension of the existing distribution system infrastructure. Many
utilities are contemplating providing performance-based rates to their
customers. They would be willing to pay compensation to the customers if the
performance falls below a minimum level. Such actions will allow utilities to
brace for the upcoming competition from other parties interested in supplying
power to the customers.
Although
higher reliability and quality are the goals of the utilities, they would like
to accomplish this while optimizing the resources. Another goal for a utility
should be improvement in system efficiency by reducing system losses. The
functions that can be automated in distribution systems can be classified into
two categories, namely, monitoring functions and control functions [2],[3],[15]. Monitoring functions are those needed to record
meter readings at different locations in the system, the system status at
different locations in the system, and events of abnormal conditions. The data
monitored at the system level are not only useful for day-to-day operations but
also for system planning. Distribution supervisory control and data acquisition
(DSCADA) systems perform some of these monitoring functions. The control
functions are related to switching operations, such as switching a capacitor,
or reconfiguring feeders. The function that is the most popular among the
utilities is fault location and service restoration or outage management. This
function directly impacts the customers as well as the system reliability.
Presently, worldwide
research and development efforts are focused in following areas to make
distribution automation more intelligent and cost effective in order to
accomplish the objective of full-scale unbundling of power systems.
- Power
system communication protocol to achieve interoperability
- Communication
system to make it commercially viable
- Switchgears
and transformers to make them self intelligent through IEDs
- Intelligent
Remote Terminal Units (RTUs)
- Intelligent
instrumentation system
- Power
system algorithm to provide quick and accurate control decision
Some
customer-related functions, such as remote load control, automated meter
reading (AMR), and remote connect/disconnect may also be considered as
distribution automation functions. However, AMR has evolved significantly itself
as a separate area. In addition, system protection can also be a part of
overall distribution automation schemes.
Almost parallel to
distribution automation system development, a development has taken place in
the Automated Mapping and Facilities Management (AM/FM) area. AM/FM system is,
in general, integrated with Geographical Information System (GIS). Advent of
high-powered graphics computer has accelerated progress in this field. Some of
the common functions performed by the AM/FM systems are distribution system
design, facility mapping, right of way/permit tracking, facilities inventory,
and system and equipment maintenance. The other functions include outage
analysis and system restoration. In the event of an outage, the calls from customers
are displayed on the system maps. Then, from the outage pattern possible causes
of outage are determined. The maps are then used to direct crew to perform
switching operations or switches can be operated remotely. Presently, advanced
distribution utilities are using and dominating either in the AM/FM systems or
in the distribution automation systems.
Information Technology (IT) has already been introduced in the power distribution management system by some utilities. This provides many useful solutions in power distribution sector utilizing the available Internet / Intranet technology. Some of them are energy audit & accounting system, trouble call management system, Internet based billing system etc.
Research and development
efforts are being carried out worldwide for full integration of AM/FM, AMR, GIS,
and IT with distribution automation to realize overall Distribution Management
System (DMS). Looking the future needs, few universities in the world have
already introduced courses on distribution automation and related areas as
given in Table-1.
Table 1: Distribution Automation Related Courses in Universities
|
Sl. No. |
Subjects |
University |
Web Link |
|
1 |
Distribution System Engineering and Flexible Control of Distribution System |
|
|
|
2 |
Analysis of Distribution System |
|
|
|
3 |
New Applications in Distribution Automation |
|
|
|
4 |
Electrical Energy Distribution Systems |
|
http://www.ee.washington.edu/undergrad/abet/courses2/457mcd.htm |
|
5 |
Distribution System
Engineering |
|
http://www.adm.uwaterloo.ca/infoucal/SA/GRAD/test/GRDcourse-ECE.html |
|
6 |
Distribution Automation |
|
|
|
7 |
Network Design and Automation |
|
|
|
8 |
Power Distribution Automation and Control |
|
http://coreapp1.drexel.edu/webcourses/CourseListing.asp?SubjCode=ECEP&Levl=GR&univ=DREX |
|
9 |
Distribution Automation |
|
|
|
10 |
Power Distribution Systems |
|
3. DISTRIBUTION AUTOMATION: GROWTH AND
CHALLENGES IN
DEVELOPING COUNTRIES
In Indian utility distribution system, the technical and commercial losses are around 45% [10]. It is envisaged that the technical part of the losses can be brought down to the minimum value with the implementation of distribution automation system. Currently reported transformer failure rate of around 15-20 % in Indian distribution systems is mainly due to non-availability of transformer health parameters and its loading conditions. This can be brought down to around 1% with the help of distribution automation system. Cost/benefit analysis of DA system justifies the capital investment for distribution automation system [11].
The
problems, described above, have been main motivation in
In
Utilities
in developing countries like
Indian
power utilities have already realized difficulties in managing vertically
integrated power systems to provide continued power supply and also in
collection of revenue from electric consumers. As a result of this, almost all
the State Electricity Boards (SEBs) in
In
view of the above, it is right time for academic institutions and Indian
industries to come forward and take responsibilities of providing a
comprehensive distribution automation solution. Academic institutions can focus
mainly on providing trained high quality manpower in the area of power
distribution automation. In addition, there is a need of intensive research
work in order to get low cost solution using the state-of-art technology in the
area. Some of the organizations like CPRI Bangalore, ERDA Vadodara, ER&DC-I
Trivandrum, CMC Hyderabad, BHEL New Delhi, and INTERRA Noida have already taken
some research initiatives in the area of distribution automation and Information
Technology (IT) in
Some universities, in the world, have already introduced courses on distribution automation. Therefore, it is justified for academic institutions in developing countries to introduce courses on distribution automation and related areas in academic curriculum in order to produce High Quality personnel (HQP) required in the country (Venkata and Pahwa 2005) [16].
4. DISTRIBUTION AUTOMATION: RESEARCH
WORK IN FUTURE
Across the world, vendors have brought out Distribution Automation (DA)
technology in a fragmented manner. No indigenous effort appears to be made in
offering complete solution of the Distribution Automation system starting from
development of various components till the integration of the complete
distribution automation systems. The future research work should be aimed at
developing indigenous know-how of full scale Distribution Automation system,
which can cover from primary substations to consumer level intelligent
automation. The future research work for power distribution automation is
expected into following broad areas.
- Customer level intelligent automation system
- Computer aided monitoring and control of Distribution
Transformers
- Substation and feeder level automation
- Data communication system for Distribution Automation
- Distribution Control Centre (DCC) software
- Pilot level demonstration projects
The possible research activities in these broad areas are given in Table 2.
Table 2: Possible Research and Development Activities in Future
|
(i). Customer Level Intelligent Automation System (a) Automated Meter (c) Embedding
Harmonic Detectors in the Meters |
|
|
(ii) Computer Aided Monitoring and Control of Distribution
Transformers (a) Remotely Operable Load Break Switches (b) Low Cost Controllers for Capacitor
Switching (c) Low Cost Pole Top RTU |
|
|
(iii) Substation and Feeder Level Automation (a) Indigenous Auto Reclosures and Sectionalizers (b) Intelligent Electronic Devices (IEDs) |
|
|
(iv) Data communication system for Distribution
Automation (a) Interfaces for Code Division Multiple
Access (CDMA) and (b) Interfaces for Global System for (c) Interfaces for Distribution Line Carrier
Communication (DLCC) (d) Interfaces for 900 Mhz Radio (e) Cost Effective Substation RTUs |
|
|
(v)
Development and Standardization of Distribution Automation software (a) Master Distribution Automation Software (b) Application / Engineering Analysis Software (c) Integration of GIS (d) Energy Audit and Accounting Software (EAAS) (e) Trouble Call Management Software (TCMS) (f) Customer Information System (CIS) (g) Web Based Metering, Billing, and Collection
System (I ) Web Based Monitoring of Distribution System |
|
|
(vi) Pilot level Demonstration Projects |
|
5. CONCLUSION
At present in
REFERENCES
[1]
S. S. Venkata, A. Pahwa, R. E. Brown, and R. D. Christie, “What Future Distribution
Engineers Need to Learn”, IEEE Trans. on
Power Systems, vol. 19, 2004, pp. 17-23.
[2]
D. Bassett, K. Clinard, J. Grainger,
[3]
J. B. Bunch, “Guidelines for Evaluating Distribution
Automation”, EPRI Report EL-3728, 1984.
[15]
A. Pahwa and J. K. Shultis, “Assessment of the Present
Status of Distribution Automation”, Engg. Experiment Station, Kansas State
Univ.,
[16]
S. S. Venkata and A. Pahwa, “Including Distribution
Automation in An Undergraduate Course”, Proceedings
of the workshop on Teaching of First Course in Power Systems,
AUTHORS’
BIOGRAPHIES
Ram Prakash Gupta received his B. E. degree in Electrical
Engineering from
Rajiv K. Varma did his B. Tech and Ph. D. from
Indian Institute of Technology (IIT),
Technical College - Bourgas,
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© March, 2000