Circuit Breaker Maintenance by Mobile Agent Software Technology

Published on January 2017 | Categories: Documents | Downloads: 277 | Comments: 0 | Views: 931
of 22
Download PDF   Embed   Report

Comments

Content

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

ABSTRACT

Circuit breakers are crucial components for power system operation. The currently adapted time-directed maintenance strategy and the emerging new conditionbased strategy require a flexible information processing technique and software architecture. In this paper, mobile agent software has been applied in implementing circuit breaker maintenance and repair tasks. Se eral potential application scenarios ha e been described and the rele ant software features ha e been discussed. The benefits of using the mobile agent techniques are discussed at the end.

www.seminarsTopics.com

!

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

I.

INTRODUCTION

Circuit breakers are crucial components for power system operations. They play an important role in switching for the routine network operation and protection of other de ices in power systems. To ensure circuit breakers are in healthy condition, periodical inspection and pre enti e maintenance are typically performed. The maintenance schedules and routines usually follow the recommendation of circuit breaker endors, although the recommended schedules may be conser ati e.

"ew maintenance techniques and methodologies are emerging, while the circuit breakers keep impro ing in their designs and functions . #s an example, some new circuit breakers ha e embedded monitoring instruments a ailable to measure the coil current profiles and the operation timing . The recorded information can be used to monitor the condition of breakers during each operation. In this case, it may be more appropriate to replace the time-directed maintenance by condition-directed maintenance practice . $hen applied properly, both the si%e of the maintenance crew and maintenance cost may be reduced greatly with this approach. Since the number of circuit breakers in a power system is usually ery big, a small maintenance cost sa ing per each circuit breaker can accumulate to a considerable benefit for the whole system. # more systematic solution is &eliability Centered 'aintenance (&C'), which can be used to select the most appropriate maintenance strategy.

www.seminarsTopics.com

*

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

+uring the maintenance or repair work, the maintenance crew will need to access information distributed across the utility and stored using different data formats. ,y equipping the crew with new information access methods to replace the old paper-based information exchange and logging method, the efficiency may be impro ed since less time will be spent on preparation, reporting and logging. #n information access method that is capable of handling heterogeneous information sources will be helpful to achie e the abo e goal. #lso, the new information access method should be secure and able to work on unreliable public networks.

The mobile agent software pro ides a flexible framework for mobile agent applications. #n agent application program can tra el through the internet-intranet to the computers where the mobile agent ser er or transporter is running. The mobile agent software also supports +istributed . ents, #gent Collaboration and Ser ice ,ridge. Compared with client ser er systems, an agent can process the data locally and thus reduce the network traffic. ,esides, the /a a platform encapsulates the network layer from the agent, which makes the programming easier. The mobile agent software may fit ery well in the circuit breaker maintenance scenario. In this paper, we considered how mobile agent software might be applied in circuit breaker maintenance and monitoring from the iewpoint of the maintenance crew.

www.seminarsTopics.com

0

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

II.

CIRCUIT BREAKER MAINTENANCE TASKS

The maintenance of circuit breakers deser es special consideration because of their importance for routine switching and for protection of other equipment. .lectric transmission system breakups and equipment destruction can occur if a circuit breaker fails to operate because of a lack of a pre enti e maintenance. The need for maintenance of circuit breaker is often not ob ious as circuit breakers may remain idle, either open or closed, for long periods of time. ,reakers that remain idle for six months or more should be made to open and close se eral time in succession to erify proper operation and remo e any accumulation of dust or foreign material on, mo ing parts and contacts.

The circuit breakers mainly consist of the interrupter assembly (contacts, arc interrupters and arc chutes), operating mechanism, operation rod, control panel, sealing system, and breaking medium (S12, oil, acuum and air). To ensure the performance of a circuit breaker, all the components should be kept in good condition3 therefore timedirected pre enti e maintenance has been widely adopted. The pre enti e maintenance tasks include periodic inspection, test, and replacement of worn or defecti e components and lubrication of the mechanical parts. The maintenance inter als are usually determined using experiences or following the recommended schedules pro ided by the endor or standard.

The maintenance practices can be di ided into three categories4 correcti e maintenance, pre enti e maintenance, and predicti e maintenance. www.seminarsTopics.com 5

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

The different strategies are summari%ed in Table I. .ach maintenance strategy has its own ad antages and disad antages, and thus most suitable application scenarios. # systematic solution is to utili%e the &eliability Centered 'aintenance (&C') methodology. It performs analysis of the failure modes and the cause-effect impacts on the de ices as it tries to find which strategy is the most cost-effecti e and appropriate for an application. The result of utili%ing the &C' techniques and tools will be an optimal maintenance schedule for a specific application scenario.

T#,6. I
'#I"T."#"C. ST&#T.7I.S

www.seminarsTopics.com

8

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

The location of the information needed to perform maintenance can be the enterprise maintenance system, the substation data concentrators and the maintenance crew9s computer.

The information about the spare parts, test procedures, historical maintenance records, and instruction manuals, etc. is typically accessible in the enterprise maintenance system. #lso, the enterprise maintenance will usually utili%e a &C' or con entional maintenance scheduling system to generate work orders. The work orders indicate when and where to perform what kind of maintenance on what de ices.

The information about the substations equipment may be retrie ed from the substation computers or concentrators. $ith the introduction of continuous monitoring of circuit breakers, the real-time data becomes a ailable for accessing in the substation concentrators. The continuous monitoring instrument may measure the coil current profiles and switching timing during the normal operation. The condition of a circuit breaker can be assessed using some signal processing and artificial intelligence techniques. In this way, the time-directed pre enti e maintenance may be replaced by condition-directed predicti e maintenance. The real-time data in the substation concentrators is also a useful complement to the historical information stored in the enterprise maintenance system. The data may be utili%ed to automatically update or populate the enterprise maintenance database.

www.seminarsTopics.com

2

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

The maintenance crew may ha e the inspection or test report stored on a mobile computer. #lso, the crew may need to update the status of the work order stored on the computer as well. Since the maintenance information is distributed among different systems, a software technique that has the flexibility of interfacing with multiple heterogeneous information systems is desired.

The software should ha e the following characteristics to meet the maintenance information exchange requirements4  Security support (encrypted data transmission, user authentication and authori%ation)  .fficient network bandwidth usage  &obust and fault-tolerant communication o er unreliable en ironment and portable personal communication de ices  #bility to integrate with heterogeneous systems  #utomatic software update to ease the user burden

www.seminarsTopics.com

:

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

III.

MOBILE AGENT SOFTWARE

There are different definitions of what is a software agent. #n agent is a proacti e software component, which is capable of acting reasonably to accomplish tasks on behalf of the user. #n agent should be autonomous and ha e sound intelligence. # good software agent should be able to adapt to the changing en ironment3 it may also be helpful to ha e the ability to exchange knowledge with other agents. #gent-based programming offers greater flexibility and adaptability than component-based programming. Compared with ob;ect-oriented software engineering, agent-oriented software engineering uses a set of high-le el, flexible abstractions to represent systems. #gents communicate with each other by passing messages or by synchroni%ation. +epending on their functions, we can classify agents into se eral categories4 <ersonal agents, mobile agents, collaborati e agents, etc.

'obile agents are small software entities that can tra el around the network, performing their functions on behalf of users. #s the next generation middle-ware infrastructure for de eloping distributed applications, it meets all the requirements mentioned abo e. Since the mobile agents tra el to the locations of the data sources and process the data locally, the network bandwidth consumption has been minimi%ed. The built-in support for security, e ent notification, and agent collaboration can greatly impro e the programming efficiency. www.seminarsTopics.com =

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

#s shown in 1ig. !, the mobile agents can tra el to de ices that ha e mobile agent ser ers or lightweight transporters running. The mobile agent ser er can run on any platform where the /a a runtime en ironment is a ailable, and the de ices without /a a >irtual 'achine (/>') are supported through a communication node. The communication node can use any proprietary protocol to talk with the mobile de ices. #s long as the communication node has the mobile agent ser er running and exposes the communication functions to the agent through some programming interface, the agent can communicate with the mobile de ices. Since the /a a en ironment cannot co er the whole range of de ices, the mobile agents need to know the programming interface in order to communicate with certain mobile de ices.

www.seminarsTopics.com

?

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

Since the mobile agent software is built on /a a platform, other functions supported by /a a platform are also a ailable for the mobile agents. #mong them, the /a a +atabase Connecti ity (/+,C) interface to access database, the &emote 'ethod In ocation (&'I) for distributed ob;ects, and the .xtensible 'arkup 6anguage (@'6) support are most notable.

www.seminarsTopics.com

!A

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

IV.

APPLICATION SCENARIOS

To reflect the distributed characteristic of the data sources, three computers are used to represent the enterprise maintenance system, the substation concentrator and the maintenance crew respecti ely as shown in 1igure below.

www.seminarsTopics.com

!!

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

The enterprise maintenance system may contain the maintenance history database, the &C' system, warehouse in entory system, and other information. The substation concentrator is in charge of collecting data from the sensors installed on the circuit breakers. Some analysis software will be running and a status report describing the circuit breaker operation can be generated. The maintenance crew uses a mobile computer to

access the information and prepares report utili%ing software mobile agents. The number of possible application scenarios is great. Bnly a few of them are gi en here to illustrate the benefits of utili%ing the mobile agent software in the circuit breaker maintenance practice.

www.seminarsTopics.com

!*

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

A. nformation Storage an! Retrie"al
The mobile agent can help storing and retrie ing all the information needed to perform maintenance or repair work. 'obile agent software supports accessing the data sa ed into heterogeneous systems. The information related to maintenance may be sa ed at heterogeneous databases and files. The heterogeneity may be reflected platform wise(differences in protocol, differences in format), concept wise (differences in schema and ocabulary, relati e incompleteness), or both. #lso, an information source may use a slow network connection, which means great network delays. #nd a source may only be operating part-time. 'obile agent software pro ides a framework to work in heterogeneous en ironments. #t first, the /a a platform is highly portable, which makes the mobile agent ser er run on a plethora of platforms. /a a also has standard #pplication <rogramming Interface (#<I) to access data source in relational database and .xtensible 'arkup 6anguage (@'6) files. Second, the mobile agent ser er will sa e the status of mobile agents, therefore pro iding reliable transmits on slow or parttime connected networks.

#gents can do sophisticated search and impro e efficiency and scalability. The mobile agents tra el to the location where the data is stored to do the processing and return with the final results only. In this way, the bandwidth consumption is minimi%ed. #lso, the mobile agents ha e abilities beyond using only the SC6 or @'6 #<I. It can www.seminarsTopics.com !0

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

utili%e some heuristic knowledge to do more complicated search. $hat an agent can do is limited by its intelligence. 1or example, in a database table, a field is named DphoneE instead of DtelephoneE. $hen an agent tries to search a field named DtelephoneE, it will fail. ,ut if the agent knows the relationship between DphoneE and DtelephoneE and it finds the DphoneE field from the database metadata, it will try to use the DphoneE field. Bf course, the semantic may be different, but it is better to return some results to the user rather than ;ust reporting Dnothing foundE.

#gents can help to make the location and format of the information transparent to users. In general, to utili%e an information source, the users are required to know the types and location of the information. DIntelligentE agents should be able to comprehend the user9s requirement and automatically find the appropriate information and ser ices. In a simple implementation, e ery agent has a knowledge base about the location of certain information and format, so the crew no longer needs to remember those tri ial things. Fe-she can ask the agent to actually do something instead of how to do something. The knowledge about the information locations can be acquired ia a central agency or mutual knowledge exchange among agents. Currently, all the information about locations are stored at a centrali%ed place and the agent can populate its location knowledge base at first. #fter that, the agent could use its own knowledge base to retrie e the information.

$hen the location or format of an information source is changed, the central database will be updated. The agent will fail when it uses its own old copy of the knowledge base. In that case, the agent will consult the central agency again to update its knowledge base.

www.seminarsTopics.com

!5

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

B. Creating Circuit Breaker #ailure Reports

"o maintenance acti ities can ensure no failure will happen. $hen a circuit breaker failure does happen, some immediate action and follow-up in estigation are required. #s an example, to file an I... Std-!0*8 compliant power circuit breaker failure report, the user needs to collect the circuit breaker information (manufacturer, type, oltage, etc.), the operating en ironment data, the description of the trouble, the effect of the failure, the single line substation diagram, the operation and timing sequence, line condition, oscillogram, etc. To gather all the information and compile a report may be time consuming and error prone, since the information may be distributed among different data sources and in ersatile formats. Therefore an automated method is preferred.

# mobile agent makes an itinerary according to its knowledge about the location of information sources and will tra el to each source and collect the information. The agent may also choose to delegate tasks to a bunch of second le el agents and edit the last returned result from other agents. The second method may be faster when there are many sources for the software agent to isit. The software agent that helps the user to create the report will create and send out additional mobile agents to the distributed information

www.seminarsTopics.com

!8

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

sources for collecting the data. The collaboration mechanism pro ided by the mobile agent software has been utili%ed to exchange information among agents. The agent may also utili%e some heuristic rules to help determine the possible causes of the failure. The generated report is in .xtensible 'arkup 6anguage (@'6) format and contains only the necessary information about the failure report . #fter gi ing the corresponding .xtensible Style sheet 6anguage (@S6) style sheets to define the appearance, the reports of different formats (e.g. FT'6 or <+1) can be automatically generated using @S6 Transformation (@S6T) tools from a single data set. Gsing @'6 to represent the report separates the content from the presentation, which makes the data more accessible and exchangeable. In fact, @'6 has been selected as the proposed standard to exchange realtime system information among control centers . ,y sa ing only the content, the storage space is also optimi%ed.

C. Circuit breaker monitoring

The distributed e ent mechanism is helpful in monitoring the status and e ents of circuit breakers. The user can select the e ent of interest to monitor. Bnce the monitoring starts, the selected e ents will be registered with the mobile agent ser er running on the corresponding substation concentrator. The concentrator can get the real-time information about the circuit breakers by communicating with sensors, and it can notify the user when the selected type of e ent happens.

www.seminarsTopics.com

!2

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

$. Security Consi!eration

Two apparent security problems arise when applying mobile agents. 1irst, the mobile agents need to be authenticated and authori%ed at the ser ers. Second, to ensure the integrity of the data, it must be transmitted in secure communication channels.

. ery mobile agent must be authenticated at first to identify whom it represents. Secure Agent supports user authentication by using the username-password pairs. Bnce identified, mobile agents can be checked against the security policy to see whether they are authori%ed to do certain things at a ser er. The #dministrator tool pro ides a userfriendly interface for the ser er security and ser ice management.

The mobile agent ser er can control agentHs access to resources depending on both the user identification and ser er permits. # user can be created for each maintenance crew. #lternati ely, a maintenance crew group can be used to represent all the crews. In 1igure 8, a mcrew group has been created, which has two members4 %ack and %anet. The mcrew group has the permissions to access maintenance-related ser ices.

The user interface to assign different types of permissions to users or groups is pro ided. The permissions are di ided into different groups for agent, class, e ent, file, etc. 1or example, the permission in the agent group decides if an agent with the user-groupHs identity can arri e or be launched to-from this ser er. The file group permission determines whether a user or group can access the local files.

www.seminarsTopics.com

!:

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

Secure communication channels among the mobile agent ser ers may become important, especially when the data passes through the public network or wireless channels. The mobile agent software pro ides options to encrypt the data when it is in transit, and thus pre ents others tampering with the data. # digital en elope will be used to protect Seale! Agents when tra elling.

#ll the abo e security measures are supported by the mobile agent software directly and thus greatly simplify the programming work. There are some other securityrelated features pro ided. #s an example, the mobile agents can work with firewalls, which is important when accessing the company Intranet from the outside public Internet is needed.

&. 'ogging an! &(perience Sharing

Software agents may help in logging and sharing maintenance experience. In the maintenance and repairing industry, experiences are often extremely important. Fa ing an effecti e way to accumulate and distribute the experiences will help a oiding common mistakes and impro ing work efficiency. Currently, most of the experiences are still passed and shared by word of mouth, therefore some good experiences may be lost with years and personnel changes. The quality of this kind of experience sharing depends on the willingness of the people to share experience and their expression abilities. It is also difficult to search a solution for a gi en problem, since it is hard to know who has the

www.seminarsTopics.com

!=

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

corresponding experience. #gents may help in recording the maintenance process and con erting it into some standard format (e.g. @'6 with standardi%ed schema). The recorded experience can be sa ed in a case-based reasoning system for future retrie ing.

#. Cost)benefit analysis

#gents can assist users in performing some standard analysis. 1or example, to determine whether in-ser ice monitoring of a circuit breaker is satisfied, a cost-benefit analysis based on the risks and in estment return may be processed automatically. In , a decision making sequence has been recommended, which consists of three stages. Some historical data will help the user to gi e a more appropriate score for assessing each failure mode.

*. +ther

Some other applications of agent technique ha e been proposed. 1or example, agents can impro e the usability of some software by pro iding a friendly user interface with ability of speech recognition and synthesis.

www.seminarsTopics.com

!?

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

V.

SUMMARY

Gtili%ing mobile agent techniques, the con enience and speed of accessing and generating maintenance data will be impro ed. $ith increasing complexity of circuit breaker equipment, more information is needed to perform the maintenance work, so an efficient data communication exchange becomes ery important. 'obile agents can

process information locally with less network bandwidth consumption. #lso its ability to pro ide reliable transmission on disconnected or low quality networks is an important merit. 'obile agent computing easily facilitates the integration and automation of the maintenance process, starting from the generation of work orders to the completion of the maintenance report. The entire process may in ol e multiple entities and steps. Thus, an automated procedure is highly desirable. $ith the ability to collaborate and update agent itineraries adapti ely, the mobile agent software pro ides an ideal framework for modeling and supporting the maintenance workflow. 1urthermore, mobile agent computing also pro ides the means by which realtime and off-line data can easily be integrated into a single distributed maintenance management system. Gsing real-time monitoring data, the maintenance system can e aluate the condition of de ices, which makes predicti e maintenance possible. The integration of real-time data may be utili%ed to impro e the maintenance management

www.seminarsTopics.com

*A

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

decisions. The platform independence feature of mobile agents pro ides interface and support for great ariety of de ices.

VI.

CONCLUSIONS

In this paper, mobile agent software has been applied in circuit breaker maintenance. Se eral representati e application scenarios ha e been described. 'obile agent software may be suitable for applying in circuit breaker maintenance practice due to its support for heterogeneous systems, security, distributed e ents, low-bandwidth usage, etc. Gsing the mobile agent software, the de elopment work can be greatly simplified. #lso, agent-based software architecture makes the application more flexible and upgradable.

www.seminarsTopics.com

*!

Seminar Report ’11

Circuit Breaker Maintenance by Mobile Agent Software Technology

VII. REFERENCES

!. Impro ing Circuit ,reaker 'aintenance 'anagement Tasks by #ppling 'obile #gent Software Technology -'. Ie%uno ic

*. I... 7uide for Selection of 'onitoring for Circuit ,reaker, I... Std C0:.!A.!-*AAA,*AA! 0. 'obile #gent Software #pplied in 'aintenance Scheduling 5. #ccelerating +e elopment with #gent Components and 7. <our 8. Circuit ,reakers -I... Computer ,'ay *AA! - <ower System by >.I. 'ehta - @. @u -'.6. 7riss

www.seminarsTopics.com

**

Sponsor Documents

Or use your account on DocShare.tips

Hide

Forgot your password?

Or register your new account on DocShare.tips

Hide

Lost your password? Please enter your email address. You will receive a link to create a new password.

Back to log-in

Close