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Rabih A. Jabr - One of the best experts on this subject based on the ideXlab platform.

  • Mixed-Integer Optimization for Volt/VAr Control in Radial Networks
    2018 4th International Conference on Renewable Energies for Developing Countries (REDEC), 2018
    Co-Authors: Mohammed Knaiber, Rabih A. Jabr
    Abstract:

    Due to the increase in load demand and capacity of distributed generation, radial distribution systems are exposed to voltage violation problems. Volt/VAr control (VVC) has a primary objective of removing voltage violations, and a secondary objective of minimizing the real power loss. Volt/VAr control operates on capacitor switches, transformer taps, and the reactive power set-points of distributed generation. In this paper, the VVC problem is solved using mixed-integer conic programming to establish a globally optimal benchmark. To improve computational performance, a Discrete Coordinate-descent algorithm is employed, starting from a solution to the continuous relaxation of the VVC mixed-integer conic program. Numerical results are reported on radial distribution networks with up to 3146 nodes. The results reveal that the Discrete Coordinate-descent algorithm, when initialized by solving a continuous conic program, can give solutions that are very close to the global optimum; these solutions are obtained within a very reasonable computing time and are superior to initiating the search from the current operating point.

  • sensitivity based Discrete Coordinate descent for volt var control in distribution networks
    IEEE Transactions on Power Systems, 2016
    Co-Authors: Rabih A. Jabr, Izudin Dzafic
    Abstract:

    The Discrete Coordinate-descent algorithm is a practical approach that is currently used in centralized Volt/VAr Control (VVC) implementations, mainly due to its good performance and speed for real-time applications. Its viability is however challenged by the increasing number of distributed generation that contribute to the VVC solution, in addition to the conventional transformer taps and switched capacitors. This paper presents the exact computation of sensitivity factors that speed up the Discrete Coordinate-descent implementation, by significantly reducing the number of forward/backward substitutions in the current injection power flow method; the speed up is achieved without affecting the control setting quality of the original implementation. The optimality of the Discrete Coordinate-descent solutions is investigated by computing the gaps relative to mixed-integer linear programming set-points, derived from a polyhedral reformulation of the VVC problem. The sensitivity-based Discrete Coordinate-descent algorithm is tested starting from two initial points, the default one given by the current control set-points, and a continuous solution obtained from a linear approximation of the VVC problem. Numerical results on networks with up to 3145 nodes show that the sensitivity-based approach significantly improves the runtime of the Discrete Coordinate-descent algorithm, and that the linear programming initialization leads to VVC solutions with gaps relative to the mixed-integer set-points that are less than 0.5%.

  • Sensitivity-Based Discrete Coordinate-Descent for Volt/VAr Control in Distribution Networks
    IEEE Transactions on Power Systems, 2016
    Co-Authors: Rabih A. Jabr, Izudin Džafić
    Abstract:

    The Discrete Coordinate-descent algorithm is a practical approach that is currently used in centralized Volt/VAr Control (VVC) implementations, mainly due to its good performance and speed for real-time applications. Its viability is however challenged by the increasing number of distributed generation that contribute to the VVC solution, in addition to the conventional transformer taps and switched capacitors. This paper presents the exact computation of sensitivity factors that speed up the Discrete Coordinate-descent implementation, by significantly reducing the number of forward/backward substitutions in the current injection power flow method; the speed up is achieved without affecting the control setting quality of the original implementation. The optimality of the Discrete Coordinate-descent solutions is investigated by computing the gaps relative to mixed-integer linear programming set-points, derived from a polyhedral reformulation of the VVC problem. The sensitivity-based Discrete Coordinate-descent algorithm is tested starting from two initial points, the default one given by the current control set-points, and a continuous solution obtained from a linear approximation of the VVC problem. Numerical results on networks with up to 3145 nodes show that the sensitivity-based approach significantly improves the runtime of the Discrete Coordinate-descent algorithm, and that the linear programming initialization leads to VVC solutions with gaps relative to the mixed-integer set-points that are less than 0.5%.

R.l. Lugtu - One of the best experts on this subject based on the ideXlab platform.

  • volt var control algorithm for modern distribution management system
    IEEE Transactions on Power Systems, 1995
    Co-Authors: Ilya Roytelman, B.k. Wee, R.l. Lugtu
    Abstract:

    In this paper, a centralized volt/VAr control (VVC) algorithm for a distribution management system is presented. The algorithm is based on the oriented Discrete Coordinate descent method and takes into account all the optimization objectives of interest in distribution system analysis: minimum power loss, power demand or the number of control steps to keep the system within constraints. Although the optimization method used belongs to the traditional class of combinatorial integer programming, the algorithm provides good speed for real-time application. Numerical examples illustrate how well the VVC algorithm works for the different types of objective functions and it's advantages in comparison with other possible optimization strategies. >

  • Volt/var control algorithm for modern distribution management system
    IEEE Transactions on Power Systems, 1995
    Co-Authors: Ilya Roytelman, B.k. Wee, R.l. Lugtu
    Abstract:

    In this paper, a centralized volt/VAr control (VVC) algorithm for a distribution management system is presented. The algorithm is based on the oriented Discrete Coordinate descent method and takes into account all the optimization objectives of interest in distribution system analysis: minimum power loss, power demand or the number of control steps to keep the system within constraints. Although the optimization method used belongs to the traditional class of combinatorial integer programming, the algorithm provides good speed for real-time application. Numerical examples illustrate how well the VVC algorithm works for the different types of objective functions and it's advantages in comparison with other possible optimization strategies.

Izudin Dzafic - One of the best experts on this subject based on the ideXlab platform.

  • sensitivity based Discrete Coordinate descent for volt var control in distribution networks
    IEEE Transactions on Power Systems, 2016
    Co-Authors: Rabih A. Jabr, Izudin Dzafic
    Abstract:

    The Discrete Coordinate-descent algorithm is a practical approach that is currently used in centralized Volt/VAr Control (VVC) implementations, mainly due to its good performance and speed for real-time applications. Its viability is however challenged by the increasing number of distributed generation that contribute to the VVC solution, in addition to the conventional transformer taps and switched capacitors. This paper presents the exact computation of sensitivity factors that speed up the Discrete Coordinate-descent implementation, by significantly reducing the number of forward/backward substitutions in the current injection power flow method; the speed up is achieved without affecting the control setting quality of the original implementation. The optimality of the Discrete Coordinate-descent solutions is investigated by computing the gaps relative to mixed-integer linear programming set-points, derived from a polyhedral reformulation of the VVC problem. The sensitivity-based Discrete Coordinate-descent algorithm is tested starting from two initial points, the default one given by the current control set-points, and a continuous solution obtained from a linear approximation of the VVC problem. Numerical results on networks with up to 3145 nodes show that the sensitivity-based approach significantly improves the runtime of the Discrete Coordinate-descent algorithm, and that the linear programming initialization leads to VVC solutions with gaps relative to the mixed-integer set-points that are less than 0.5%.

Izudin Džafić - One of the best experts on this subject based on the ideXlab platform.

  • Sensitivity-Based Discrete Coordinate-Descent for Volt/VAr Control in Distribution Networks
    IEEE Transactions on Power Systems, 2016
    Co-Authors: Rabih A. Jabr, Izudin Džafić
    Abstract:

    The Discrete Coordinate-descent algorithm is a practical approach that is currently used in centralized Volt/VAr Control (VVC) implementations, mainly due to its good performance and speed for real-time applications. Its viability is however challenged by the increasing number of distributed generation that contribute to the VVC solution, in addition to the conventional transformer taps and switched capacitors. This paper presents the exact computation of sensitivity factors that speed up the Discrete Coordinate-descent implementation, by significantly reducing the number of forward/backward substitutions in the current injection power flow method; the speed up is achieved without affecting the control setting quality of the original implementation. The optimality of the Discrete Coordinate-descent solutions is investigated by computing the gaps relative to mixed-integer linear programming set-points, derived from a polyhedral reformulation of the VVC problem. The sensitivity-based Discrete Coordinate-descent algorithm is tested starting from two initial points, the default one given by the current control set-points, and a continuous solution obtained from a linear approximation of the VVC problem. Numerical results on networks with up to 3145 nodes show that the sensitivity-based approach significantly improves the runtime of the Discrete Coordinate-descent algorithm, and that the linear programming initialization leads to VVC solutions with gaps relative to the mixed-integer set-points that are less than 0.5%.

Ilya Roytelman - One of the best experts on this subject based on the ideXlab platform.

  • volt var control algorithm for modern distribution management system
    IEEE Transactions on Power Systems, 1995
    Co-Authors: Ilya Roytelman, B.k. Wee, R.l. Lugtu
    Abstract:

    In this paper, a centralized volt/VAr control (VVC) algorithm for a distribution management system is presented. The algorithm is based on the oriented Discrete Coordinate descent method and takes into account all the optimization objectives of interest in distribution system analysis: minimum power loss, power demand or the number of control steps to keep the system within constraints. Although the optimization method used belongs to the traditional class of combinatorial integer programming, the algorithm provides good speed for real-time application. Numerical examples illustrate how well the VVC algorithm works for the different types of objective functions and it's advantages in comparison with other possible optimization strategies. >

  • Volt/var control algorithm for modern distribution management system
    IEEE Transactions on Power Systems, 1995
    Co-Authors: Ilya Roytelman, B.k. Wee, R.l. Lugtu
    Abstract:

    In this paper, a centralized volt/VAr control (VVC) algorithm for a distribution management system is presented. The algorithm is based on the oriented Discrete Coordinate descent method and takes into account all the optimization objectives of interest in distribution system analysis: minimum power loss, power demand or the number of control steps to keep the system within constraints. Although the optimization method used belongs to the traditional class of combinatorial integer programming, the algorithm provides good speed for real-time application. Numerical examples illustrate how well the VVC algorithm works for the different types of objective functions and it's advantages in comparison with other possible optimization strategies.