Generation expansion planning in electricity markets: A novel framework based on dynamic stochastic MPEC

This paper presents a novel framework for generation expansion planning (GEP) of restructured power systems under uncertainty in a multi-period horizon, which includes generation investment from a price maker perspective. The investment problem is modeled as a bi-level optimization problem. The first level problem includes decisions related to investment in order to maximize total profit in the planning horizon. The second level problem consists of maximizing social welfare where the power market is cleared. Rival uncertainties on offering and investment are modeled using sets of scenarios. The bi-level optimization problem is then converted to a dynamic stochastic MPEC and represented as a mixed integer linear program (MILP) after linearization. The proposed framework is examined on a typical six-bus power network, MAZANDARAN regional electric company (MREC) transmission network as an area of IRAN interconnected power system and IEEE RTS 24-bus network. Simulation results confirm that the proposed framework can be a useful tool for analyzing the behavior of investments in electricity markets.     

On the convergence of stationary sequences in topology optimization

We consider structural topology optimization problems including unilateral constraints arising from non‐penetration conditions in contact mechanics. The resulting non‐convex non‐smooth problems are instances of mathematical programs with equilibrium constraints (MPEC), or bi‐level programs. Applying nested (implicit programming) algorithms to this class of problems is problematic owing to the singularity of the feasible set. We propose a perturbation strategy combining the relaxation of the equilibrium constraint with the restriction of the design domain to its regular part only. This strategy allows us to attack the problem numerically using standard non‐linear programming algorithms. We rigorously study the optimality conditions for the original singular problem as well as the convergence of stationary points and globally optimal solutions to approximating problems towards respective stationary points and globally optimal solutions to the original problem. A limited numerical benchmarking of the algorithm is performed. Copyright © 2005 John Wiley & Sons, Ltd.     

A Novel Stackelberg-Game-Based Energy Storage Sharing Scheme Under Demand Charge

Demand response(DR) using shared energy storage systems(ESSs) is an appealing method to save electricity bills for users under demand charge and time-of-use(TOU) price. A novel Stackelberg-game-based ESS sharing scheme is proposed and analyzed in this study. In this scheme, the interactions between selfish users and an operator are characterized as a Stackelberg game. Operator holds a large-scale ESS that is shared among users in the form of energy transactions. It sells energy to users and sets...     

Photoelectrochemical and Raman imaging studies of chemical and mechanical properties of thermally grown titanium oxide scales

Abstract

The present work focuses on thin TiO₂ scales (up to 3 μm). The use of both micro-photoelectrochemistry (MPEC) and Raman imaging aims to get chemical and mechanical information at a micron scale. In particular, the MPEC technique allows images of the history of strain and adhesion levels of the oxide/metal interface to be realised. A set of photocurrent images recorded at different applied potentials allows different images to be constructed, Structural Quality Image (SQI) and Interface Cohesion Image (ICI). In addition, Raman spectroscopy images the chemical nature of the scale, topography of the surface and local stress level in the scale. Combining both techniques is a powerful tool in elucidating the mechanisms of thermal oxidation.     

Review of formulations for structural and mechanical system optimization

Alternative formulations for optimization and simulation of structural and mechanical systems and other related fields are reviewed. The material is divided roughly into two parts. Part 1 focuses on the developments in structural and mechanical systems, including configuration and topology optimization. Here the formulations are classified into three broad categories: (i) the conventional formulation where only the structural design variables are treated as optimization variables, (ii) simultaneous analysis and design (SAND) formulations where design and some of the state variables are treated as optimization variables, and (iii) a displacement-based two-phase approach where the displacements are treated as unknowns in the outer loop and the design variables as the unknowns in the inner loop. Part 2 covers more general formulations that are applicable to diverse fields, such as economics, optimal control, multidisciplinary problems and other engineering disciplines. In these fields, SAND-type formulations have been called mathematical programs with equilibrium constraints (MPEC), and partial differential equations (PDE)-constrained optimization problems. These formulations are viewed as generalizations of the SAND formulations developed in the structural optimization field. Based on the review, it is concluded that the basic ideas of the formulations presented in diverse fields can be integrated to conduct further research and develop alternative formulations and solution procedures for practical engineering applications. The paper lists 187 references on the subject.     

数字电视地面广播技术与发展

本文系统介绍了数字电视地面广播的标准、系统、播出试验和设备以及我国在数字电视地面广播领域所做出的成绩,对数字电视地面广播做了较详细的描述和探讨.     

Strategic offers in day-ahead market co-optimizing energy and reserve under high penetration of wind power production: An MPEC approach

This work based on Stackelberg hypothesis, which considers a conventional power producer exercising their dominant position in an electricity pool with high penetration of wind power production. A bi-level optimization model is used to describe the delivery of a single settled hourly auction process. The upper-level problem illustrates the expected profit optimization of the strategic producer whereas the lower-level problem represents the energy-only market clearing process through a two-stage stochastic program. The bi-level problem is recast into mathematical programming with equilibrium constraints (MPEC), which is then reformulated into an MILP. These transformations occur using the Karush-Kuhn-Tucker optimality conditions and the strong duality theory. Energy dispatch and reserve deployment are co-optimized under various scenarios of wind production uncertainty realization. The suggested model provides optimal strategic offers and local marginal prices under different levels of wind penetration and network line transmission capacities. © 2018 American Institute of Chemical Engineers AIChE J, 65: e16495 2019     

未来VoD系统的发展方向及技术方案

随着宽带技术及视频技术的飞速发展,在不久的将来视频点播系统VoD交得到大规模的应用与推广。目前关于VoD系统的研究及实现技术方式很多,文章系统地介绍了各主要部分关键技术的未来发展方向及可能采取的最佳技术方案。     

MPEC问题的精确罚函数法收敛性

应用精确罚函数方法,将MPEC问题转化为目标函数含有罚项的一般约束优化问题。当罚因子足够大时,该约束优化问题的极小点收敛于原问题的极小点。     

MPEC problem formulations and solution strategies with chemical engineering applications

With the development and widespread use of large-scale nonlinear programming (NLP) tools for process optimization, there has been an associated application of NLP formulations with complementarity constraints in order to represent discrete decisions. Also known as mathematical programs with equilibrium constraints (MPECs), these formulations can be used to model certain classes of discrete events and can be more efficient than a mixed integer formulation. However, MPEC formulations and solution strategies are not yet fully developed in process engineering. In this study, we discuss MPEC properties, including concepts of stationarity and linear independence that are essential for well-defined NLP formulations. Nonlinear programming based solution strategies for MPECs are then reviewed and examples of complementarity drawn from chemical engineering applications are presented to illustrate the effectiveness of these formulations.