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Journal Article•DOI•

Object-oriented programming for flexible software: example of a load flow

01 Aug 1990-IEEE Transactions on Power Systems (IEEE)-Vol. 5, Iss: 3, pp 689-696
TL;DR: The basic elements of object-oriented programming (OOP) are introduced and the advantages of this software approach for energy management systems are demonstrated with an implementation of the load flow function as a concrete example.
Abstract: The basic elements of object-oriented programming (OOP) are introduced. The advantages of this software approach for energy management systems are demonstrated with an implementation of the load flow function as a concrete example. Object-oriented software is shown to be very flexible. Object-oriented class libraries enable the programmer to reuse the code efficiently. OOP emphasizes programming on a higher, conceptual level. The message passing algorithm of OOP supports descriptive programming. The object-oriented model is very similar to the frame-based knowledge representation used in artificial intelligence. >
Citations
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Journal Article•DOI•
TL;DR: A new restoration strategy consisting of two steps: candidate set generation and fuzzy decision making, which can generate the most preferable plan is proposed.
Abstract: Due to many conflicting goals, the power service restoration problem is a multiple-criteria decision making problem. This paper proposes a new restoration strategy consisting of two steps: candidate set generation and fuzzy decision making, which can generate the most preferable plan. The object-oriented paradigm has been adopted in the development of the system and three models-object model, functional model, dynamic model-have been designed. The test results have shown the effectiveness of the proposed method.

149 citations


Cites background from "Object-oriented programming for fle..."

  • ...In recent years, OOP is finding more applications in the power system problems [ 12 ,13]....

    [...]

Journal Article•DOI•
TL;DR: This paper presents the methodology used in the development of a new generation of software suitable for the analysis and control of large-scale power networks containing FACTS-controlled branches, developed under the UNIX/sup TM/ environment.
Abstract: This paper presents the methodology used in the development of a new generation of software suitable for the analysis and control of large-scale power networks containing FACTS-controlled branches. A Newton-Raphson load flow is used in this paper to emphasise the benefits and drawbacks introduced by the object-oriented technology when applied to 'number-crunching' power engineering solutions. The Newton-Raphson algorithm exhibits quadratic convergence for cases with FACTS-controlled branches. Full details of the prowess of this algorithm are given in a companion paper. C/sup ++/ has been used to develop compact and easy-to-maintain power systems conventional sparsity software. To aid portability the software has been developed under the UNIX/sup TM/ environment.

87 citations

Journal Article•DOI•
TL;DR: Object-based graphical user interfaces that may be used as flexible, device independent front-ends for power system simulation and control are discussed and an experimental prototype GUI suitable for energy management systems or operator training simulators is described.
Abstract: Object-based graphical user interfaces (GUIs) that may be used as flexible, device independent front-ends for power system simulation and control are discussed. An experimental prototype GUI suitable for energy management systems or operator training simulators is described. The GUI is based on the X window environment and uses multiple windows to display differing views of the system and direct mouse manipulations to affect the various power system objects in a consistent fashion. An editing portion of the system allows the dynamic construction of one-line diagrams, although an advanced automatic display generation feature capable of constructing layouts based on database information and sophisticated routing and layout heuristics is also provided. The X window (and C) basis of the implementation of the system provides for its relative platform and operating system independence, and allows the networked operation of multiple platforms running the same functions. The aim of this study is to document the generic features and advantages of such a GUI. >

79 citations

Journal Article•DOI•
TL;DR: It is found that OOP based C++ load flow programs are as efficient as their nonOOP counterparts.
Abstract: Application of OOP concepts and the C++ programming language to power system simulation has been explored An efficient platform for power system simulation applications has been proposed By emulating a physical power laboratory, a generic power network container has been built A module, which can be used to solve sparse matrix equations of any data types, has been implemented Two load flow applications, a DC load flow and an AC load flow, have been discussed It is found that OOP based C++ load flow programs are as efficient as their nonOOP counterparts

75 citations


Cites background or methods from "Object-oriented programming for fle..."

  • ...It is found that the OOP based C++ load flow programs are as efficient as their non-OOP counterparts....

    [...]

  • ...With the operators properly overloaded, user-defined data types in C++ could be used as if they were compiler build-in data types (int ... )....

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Journal Article•DOI•
Jun Zhu, David Lubkeman1•
TL;DR: It is demonstrated that object-oriented technology, when applied to each stage of software development, can help achieve complicated tasks in power system simulations.
Abstract: The software systems developed for power system simulations have evolved into such complicated systems that the applied design practices appear inadequate to support further enhancement and maintenance. The major obstacles stem directly or indirectly from the conventional function-oriented software development methodologies. To overcome the drawbacks of these methodologies, this paper proposes applying an object-oriented technology for power system software development. As an illustration of this approach, the object modeling technique (OMT), an object-oriented software development methodology, is used to develop a distribution network analysis system. With this technique, a generic distribution circuit object model (DCOM) is designed based on the real-world concepts and implemented with object-oriented programming techniques. The developed DCOM is capable of supporting a wide range of distribution applications and allowing modification and maintenance over a long period of time. The performed case study has demonstrated that object-oriented technology, when applied to each stage of software development, can help achieve complicated tasks in power system simulations.

67 citations

References
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Journal Article•DOI•
TL;DR: In this paper, a nonlinear programming problem for capacitors placed on a radial distribution system is formulated and a solution algorithm is developed to find the optimal size of capacitors so that the power losses will be minimized for a given load profile while considering the cost of the capacitors.
Abstract: A capacitor sizing problem for capacitors placed on a radial distribution system is formulated as a nonlinear programming problem, and a solution algorithm is developed. The object is to find the optimal size of the capacitors so that the power losses will be minimized for a given load profile while considering the cost of the capacitors. The formulation also incorporates the AC power flow model for the system and the voltage constraints. The solution algorithm developed for the capacitor sizing problem is based on a Phase I-Phase II feasible directions approach. Novel power flow equations and a solution method, called DistFlow, for radial distribution systems are introduced. The method is computationally efficient and numerically robust, especially for distribution systems with large r/x ratio branches. DistFlow is used repeatedly as a subroutine in the optimization algorithm for the capacitor sizing problem. The test results for the algorithm indicate that the method is computationally efficient and has good convergence characteristics. >

1,391 citations

Journal Article•DOI•
TL;DR: In this paper, a direct simultaneous solution for all of the unknowns in the Lagrangian function on each iteration is proposed, where each iteration minimizes a quadratic approximation of the Lagrangeian.
Abstract: The classical optimal power flow problem with a nonseparable objective function can be solved by an explicit Newton approach. Efficient, robust solutions can be obtained for problems of any practical size or kind. Solution effort is approximately proportional to network size, and is relatively independent of the number of controls or binding inequalities. The key idea is a direct simultaneous solution for all of the unknowns in the Lagrangian function on each iteration. Each iteration minimizes a quadratic approximation of the Lagrangian. For any given set of binding constraints the process converges to the Kuhn-Tucker conditions in a few iterations. The challenge in algorithm development is to efficiently identify the binding inequalities.

817 citations

Journal Article•DOI•
01 Nov 1967
TL;DR: With this method, direct solutions are computed from sparse matrix factors instead of from a full inverse matrix, thereby gaining a significant advantage in speed, computer memory requirements, and reduced round-off error.
Abstract: Matrix inversion is very inefficient for computing direct solutions of the large sparse systems of linear equations that arise in many network problems. Optimally ordered triangular factorization of sparse matrices is more efficient and offers other important computational advantages in some applications. With this method, direct solutions are computed from sparse matrix factors instead of from a full inverse matrix, thereby gaining a significant advantage in speed, computer memory requirements, and reduced round-off error. Improvements of tea to one or more in speed and problem size over present applications of the inverse can be achieved in many cases. Details of the method, numerical examples, and the results of a large problem are given.

780 citations

Journal Article•DOI•
TL;DR: The efficiency of the sparse vector methods is verified by tests on a 156-bus, a 1598-bus and a 2265-bus system and the new methods are significantly faster than the established sparse matrix techniques.
Abstract: Sparse vector methods enhance the efficiency of matrix solution algorithms by exploiting the sparsity of the independent vector and/or the desire to know only a subset of the unknown vector. This paper shows how these methods can be efficiently implemented for sparse matrices. The efficiency of the sparse vector methods is verified by tests on a 156-bus, a 1598-bus and a 2265-bus system. In all cases tested, the new methods are significantly faster than the established sparse matrix techniques.

338 citations

Journal Article•DOI•
TL;DR: This paper reports on the extensions for one particular query language and data manager and gives performance figures for a prototype implementation of this construct, and suggests that more powerful database systems can be built by supporting database procedures as full-fledged database objects.
Abstract: This paper suggests that more powerful database systems (DBMS) can be built by supporting database procedures as full-fledged database objects. In particular, allowing fields of a database to be a collection of queries in the query language of the system is shown to allow the natural expression of complex data relationships. Moreover, many of the features present in object-oriented systems and semantic data models can be supported by this facility.In order to implement this construct, extensions to a typical relational query language must be made, and considerable work on the execution engine of the underlying DBMS must be accomplished. This paper reports on the extensions for one particular query language and data manager and then gives performance figures for a prototype implementation. Even though the performance of the prototype is competitive with that of a conventional system, suggestions for improvement are presented.

157 citations

Trending Questions (1)
What is knowledge representation in artificial neural network?

The object-oriented model is very similar to the frame-based knowledge representation used in artificial intelligence.