PSERC - Power Systems Engineering Research Center

							Power System Monitoring Using
Wireless Substation and System-
    Wide Communications

       Mobile Agent Part

      Mladen Kezunovic (P.I.)
           Xiangjun Xu
      Texas A&M University

           PSerc Review Meeting
    College Station, November 7, 2002
                                        PSERC
             Outline
                                        PSERC


 Introduction
 Major Results
   Maintenance Scheduling
   Circuit Breaker Monitoring and Maintenance
   Agent-Oriented Approach for Workflow
    Management
 Publications
 Conclusions

                                           2
        Introduction
                                 PSERC

• System wide communications are
  aimed at power system monitoring and
  maintenance applications
• MERL’s Concordia mobile agent
  software has been applied to solve
  system wide communication problems
• Project was initiated in September
  2000 and ended in August 2002

                                    3
      Statement of Work
                                   PSERC


• Study of the mobile agent software
  and comparison with other distributed
  systems
• Study of the scenarios for application
  of the mobile agent software
• Agent-oriented approach applied in the
  maintenance process
• Documenting the research results
                                      4
Application Scenario
                                                                           PSERC
                              Enterprise Maintenance System
Maintenance
Crew


                                                                             ISO


                            Mobile Agent Server



                                                                  Report
                             Database              Rule Base



         Data files       Signal Analysis         Expert System


                                     Substation data concentrator



                      Data
                      Acquisition
                      Unit
                                                                               5
     Requirements on
   Communication Method            PSERC

 Working on distributed information
  among multiple entities (both
  geographically and organizationally)
 Working on heterogeneous systems
 Working on low-bandwidth networks
 Supporting user level access control
 Providing user friendly interfaces


                                         6
      Concordia Mobile Agent
            Software
                                           PSERC


• A cross-platform middleware software
  implemented in Java.
• It supports a wide variety of devices, from
  high-end servers to hand held computers.
• Mobile agents travel to the information
  source and reduce network bandwidth
  usage.
• It provides many useful functions to simplify
  development.

                                                  7
Major Results
   Maintenance Scheduling in
   Deregulated Environment         PSERC


• The diverse ownership of the
  equipment may lead to contradictory
  goals
• Intensive communication and
  coordination among market
  participants are required.



                                        9
     Software for Maintenance
            Scheduling                                                    PSERC

• The original scheduling problem is
  decomposed into two sub-problems.
• Mobile agent travels between ISO and
  GENCO, exchanges data until a solution is
  obtained.
                                Min        z
                                          z  f ( y)  (b  F ( y))T u i , i  1 n p
                                                                      p
                                S .T .
                                         (b  F ( y))T u i  0 , i  1 nr
                                                        r
    GENCO Master problem (IP)

Initial solution        Cut
                                         Max      (b  F ( y ))T u
                                         S .T .   AT u  c
        ISO Sub-problem (LP)                      u0
                                                                               10
                 Benefits
                                       PSERC


• Working on heterogeneous systems
• Possessing more flexible system
  structure
• Providing a solution for utilities who do
  not want to expose their data to other
  entities



                                          11
   Circuit Breaker Monitoring
        and Maintenance       PSERC


• A prototype system utilizing Concordia
  for CB applications has been built.
• The system has been integrated with
  the CB monitoring software.




                                       12
 User Interface – Example #1
(Retrieve Circuit Breaker Info)
                             PSERC




                                  13
User Interface – Example #2
 (Display COMTRADE file) PSERC




                            14
   Agent-Oriented Approach for
     Workflow Management PSERC

• Agent sensors
  • subscribing to events of interest
• Agent effectors
  • callback functions
       External                         Inference
       events               Facts       Engine


                  Actions   Callback    Rule base
                            functions

                                                    15
      Benefits of Agent-Oriented
              Approach         PSERC


• Proactive software agents rather than
  just reactive
• Better assisting the maintenance crew
• Higher level abstraction and
  encapsulation
• Better software structure



                                          16
              Publications
                                        PSERC

• X. Xu, M. Kezunovic, “Mobile Agent Software
  Applied in Maintenance Scheduling”, NAPS
  2001,
• X.Xu, M.Kezunovic, D.Wong, "Agent-Oriented
  Approach to Work Order Management for
  Circuit Breaker Maintenance", IEEE PES
  Summer Meeting 2002
• M.Kezunovic, X.Xu, D.Wong, "Improving
  Circuit Breaker Maintenance Management
  Tasks by Applying Mobile Agent Software
  Technology", IEEE T&D Conference 2002, Asia
  Pacific
                                           17
               Conclusions
                                         PSERC

• A prototype system utilizing Concordia
  mobile agent software for circuit breaker
  maintenance has been built.
• Interfacing between the real time CBM
  system and agent-based system for system-
  wide communications has been
  implemented
• Real application scenarios provided by
  utilities are still not available.
• Current focus has shifted to investigating
  the agent-oriented approach.               18