4.5 Modified System Architecture
4.5.1 Integrated Design Subsystem
1 *
Figure 4.4 Class diagrams illustrating the relationship among a distribution system, a project and a modification.
4.5.1 Integrated Design Subsystem
A project provides storage for results from design tools. Despite the fact that results from different design calculations may interact with one another, the architecture shown in Figure 4.1 does not support the idea given by a project. That is, in Figure 4.1 there is no planned way for the design applications to cooperate.
<<subsystem>>
Figure 4.5 Subsystem diagrams after considering integrated design concept (IDI: Integrated Design Interface).
Now consider Figure 4.5 which represents a new approach to design. Figure 4.5 is similar to Figure 4.1, except that Figure 4.5 introduces an additional subsystem, the Integrated Design Subsystem. The main responsibility of the Integrated Design Subsystem is to combine circuit modifications from any set of design applications that use the IDI interface. Hence, the outputs from different design programs that do not know one another may be concatenated together into one set of modifications to be performed on the circuit models.
In Figure 4.1 each individual design application talked directly to the MCI interface of the Circuit Model. In Figure 4.5 design applications are not
allowed to talk directly to the circuit model whenever they need to modify the circuit. That is, in order to effect the circuit model, the design applications must use the Integrated Design Subsystem and its IDI interface.
Also note that the GUI Input Subsystem may use the IDI interface so that direct user modifications may be mixed with the outputs of various design programs
Notice that a project is not a distribution system. Rather, it is the set of changes that are planned for the distribution system. That is why only the changes are to be stored in the Data Subsystem. The Integrated Design Subsystem can access the Data Subsystem to read any project associated with a given distribution system, and can make the changes accordingly on the system. Likewise, via operations such as adding some new modification or deleting some existing modifications, an existing project can be manipulated by the Integrated Design Subsystem and then stored back to the Data Subsystem.
Another responsibility of the Integrated Design Subsystem is to measure projects against a given system aspect (e.g., efficiency, reliability and so forth). Actually, the evaluation of a system aspect is provided as a service from analysis tools. For instance, the circuit loss calculation can be handled by a power flow program. The Integrated Design Subsystem delegates the project measurement job to the Evaluation Subsystem, a subsystem within the Integrated Design Subsystem. The Evaluation Subsystem knows what system aspect is handled by what analysis tool, and can make calls to analysis tools.
Let us assume that there exist four projects obtained from the following strategies:
• Strategy 1: Place capacitors
• Strategy 2: Perform phase balancing
• Strategy 3: Place capacitors followed by phase balancing
• Strategy 4: Phase balance followed by placing capacitors.
The Integrated Design Subsystem is asked to find the best one based on the minimum circuit loss aspect. Then the Integrated Design Subsystem will use the Evaluation Subsystem to manage four different strategies. The Evaluation Subsystem compares the alternative designs. In performing evaluations, the Evaluation Subsystem requests each project to be implemented in turn. For each such project, the Evaluation Subsystem calls the Analysis Subsystem (the power flow program to be specific) and gathers circuit loss results. The results concerning the best project can then be reported.
4.6 References
[4.1] J. C. Carlisle, A. A. El Keib, D. Boyd and K. Nolan, “A Review of Capacitor Placement Techniques on Distribution Feeders,” Proceedings of the Twenty-Ninth Southeastern Symposium on System Theory, 97TB100097, pp. 359-365.
[4.2] G. A. Bortignon, and M. E. El Hawary, “A Review of Capacitor Placement Techniques for Loss Reduction in Primary Feeders on Distribution Systems,”
Proceedings of the 1995 Canadian Conference on Electrical and Computer Engineering, 95TH8103, vol. 2, pp. 684-687
[4.3] H. L. Willis, Power Distribution Planning Reference Book, New York: Marcell Dekker, Inc., 1997.
[4.4] Distribution Workstation: Specifications, RP 3079-1 Electric Power Research Institute, Palo Alto, CA, April 1991
[4.5] W. H. Esselman and G. Z. Ben-Yaacov, “EPRI-Developed Computer Programs for Electric Utilities,” IEEE Comp. Applications in Power, vol. 1, no. 2, April 1988, pp. 18-24.
[4.6] R. Pooley and P. Stevens, Using UML: Software Engineering with Objects and Components, Addison-Wesley Longman, 1999.
[4.7] J. Rumbaugh, M. Blaha, W. Premerlani, F. Eddy and W. Lorensen, Object-Oriented Modeling and Design, Englewood Cliffs, USA: Prentice Hall, 1991.
[4.8] D. D'Souza and A. C. Wills, Objects, Components, and Frameworks With UML, Addison-Wesley Longman, 1998.
[4.9] G. Booch, J. Rumbaugh and I. Jacobson, The Unified Modeling Language User Guide, Addison Wesley Longman, 1998.
[4.10] E. Gamma, R. Helm, R. Johnson and J. Vlissides, Design Patterns: Elements of Reusable Object-Oriented Software, Reading, Massachusetts: Addison-Wesley, 1995.
[4.11] C. Larman, Applying UML and Patterns, Upper Saddle River, NJ: Prentice Hall, 1998.
[4.12] OMG Unified Modeling Language Specification, Version 1.3, Object Management Group, Inc., June 1999.
[4.13] D. G. Flinn and R. C. Dugan, “A Database for Diverse Power System Simulation Applications,” IEEE Trans. Power Systems, vol. 7, no. 2, May 1992, pp. 784-790.
[4.14] J. Zhu and D. Lubkeman, “Object-oriented development of Software systems for Power System Simulations,” IEEE Trans. Power Systems, vol. 12, no. 2, May 1997, pp. 1002-7.
[4.15] R. Broadwater, J. Thompson, M. Ellis, H. Ng, N. Singh and D. Loyd,
“Application Programmer Interface for the EPRI Distribution Engineering Workstation,” IEEE Trans. Power Systems, vol. 10, no. 1, February 1995, pp.
499-505.
[4.16] J. Britton, “An Open, Object-Based Model as the Basis of an Architecture for Distribution Control Centers,” IEEE Trans. Power Systems, vol. 7, no. 4, November 1992, pp. 1500-8.
[4.17] L. G. Osterlund, “Component Technology,” IEEE Comp. Applications in Power, vol. 13, no. 1, January 2000, pp. 17-25.