Short-term Hydropower Planning System

The Thesis gives a decision support framework that has significant impact on the economic performance and viability of a hydropower company. The studyaddresses the short-term hydropower planning problem in the Nordic deregulated electricity market. The basics of the Nordic electricity market, trading mechanisms, hydropower system characteristics and production planning are presented in the Thesis. The related modelling theory and optimization methods are covered aswell. The Thesis provides a mixed integer linear programming model applied in asuccessive linearization method for optimal bidding and scheduling decisions inthe hydropower system operation within short-term horizon. A scenario based deterministic approach is exploited for modelling uncertainty in market price and inflow. The Thesis proposes a calibration framework to examine the physical accuracy and economic optimality of the decisions suggested by the model. A calibration example is provided with data from a real hydropower system using a commercial modelling application with the mixed integer linear programming solver CPLEX.

Short-term expansion planning of radial electrical distribution systems using mixed-integer linear programming

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A Column-Generation Approach for a Short-Term Production Planning Problem in Closed-Loop Supply Chains

We present a new model formulation for a multi-product lot-sizing problem with product returns and remanufacturing subject to a capacity constraint. The given external demand of the products has to be satisfied by remanufactured or newly produced goods. The objective is to determine a feasible production plan, which minimizes production, holding, and setup costs. As the LP relaxation of a model formulation based on the well-known CLSP leads to very poor lower bounds, we propose a column-generation approach to determine tighter bounds. The lower bound obtained by column generation can be easily transferred into a feasible solution by a truncated branch-and-bound approach using CPLEX. The results of an extensive numerical study show the high solution quality of the proposed solution approach.

Prosessijohtaminen ja lyhyen aikavälin rahoitussuunnittelun kehittäminen: case Isko Oyj.

Tutkielman päätavoitteena oli kehittää kohdeyrityksen lyhyen aikavälin rahoitussuunnittelua prosessijohtamisen periaatteiden mukaisesti. Tutkimus jakaantui metodologisesti kahteen osaan: teoriaosassa käytettiin käsiteanalyyttistä tutkimusotetta ja empiriaosassa toiminta-analyyttistä tutkimusotetta. Empiirinen tutkimus toteutettiin tutkimalla kohdeyrityksen liiketoimintaprosesseja. Yksi rahoitussuunnittelun kannalta merkittävä prosessi, maahantuontiprosessi, valittiin tarkemmin kuvattavaksi ja analysoitavaksi. Yrityksen toimintaa tarkasteltaessa todettiin, että toiminnan ohjaaminen prosessijohtamisen periaatteiden mukaisesti ja rahoitussuunnittelun tunnistaminen prosessin asiakkaaksi parantaisi informaatiovirtojen laatua ja samalla lisäisi rahoitussuunnitelmien validiutta. Kohdeyrityksellä ei ole tällä hetkellä käytössään prosessiorganisaatiota. Prosessiajattelun mukaisella yrityksen tarkastelulla lisättiin yrityksen toiminnan ymmärrystä. Samalla luotiin edellytykset toiminnan kehittämiselle. Tutkimuksen tuloksena kohdeyritykselle laadittiin toimenpide-ehdotuksia maahantuontiprosessin kehittämiseksi siten, että yrityksen maksuvalmiutta pystyttäisiin paremmin suunnittelemaan ja ylläpitämään.

Kassanhallinta kuntasektorilla -sovellus Etelä-Karjalan ydinkuntien likvidimpien varojen osalta

Tutkielmassa analysoidaan kunnan kassanhallinnan likvidimpien varojen prosessien toteuttamista, kun tavoitteena on kustannustehokkuuden parantaminen. Lisäksi selvitetään Etelä-Karjalan ydinkuntien eli Lappeenrannan, Imatran ja Joutsenon mahdollisuuksia tehostaa yhteistyötä taloushallinnon alueella. Työn teoriaosassa tarkastellaan kuntasektorin kassanhallintaa erityisesti myyntisaamisten ja ostovelkojen hallinnan osalta. Keskeistä on löytää prosesseista kustannuksia ja viivettä minimoivia menettelytapoja, joita olisi mahdollista hyödyntää kunnan kassanhallinnassa. Tehokkaassa kassanhallinnassa korostuu yhä enenevissä määrin informaatioteknologian rooli. Tästä johtuen tutkimuksessa kartoitetaan perinteisten menettelytapojen automatisoinnin mahdollisuuksia ja etuja. Empiirisessä osassa tarkastellaan kohdekuntien kassanhallinnan menettelytapoja sekä niiden yhtäläisyyksiä ja eroavuuksia. Lisäksi kartoitetaan yhteistyön lisäämisen mahdollisuuksia ja esteitä sekä määritetään käytetyn aineiston perusteella tehokkaan kassanhallinnan edellyttämät menettelytavat. Tutkimuksesta voidaan päätellä kuntien tavoittelevan joustavampia ja kustannuksia minivoivia kassanhallinnan menettelytapoja vaikka perinteisten menetelmien uudistaminen ei aina olekaan helppoa. Automatisointi ja prosessien virtaviivaistaminen on taloudellisen menestyksen ja kilpailussa mukana pysymisen edellytys. Tehokkuuden etsiminen tiiviimmän yhteistyön kautta olisi järkevää, mutta asenteet ja kontrollin menettämisen pelko estävät yhteistyöhön perustuvien suuruuden etujen saavuttamisen.

Process planning methodology: dynamic short-term planning for off-site construction in Slovenia

Planning is a vital element of project management but it is still not recognized as a process variable. Its objective should be to outperform the initially defined processes, and foresee and overcome possible undesirable events. Detailed task-level master planning is unrealistic since one cannot accurately predict all the requirements and obstacles before work has even started. The process planning methodology (PPM) has thus been developed in order to overcome common problems of the overwhelming project complexity. The essential elements of the PPM are the process planning group (PPG), including a control team that dynamically links the production/site and management, and the planning algorithm embodied within two continuous-improvement loops. The methodology was tested on a factory project in Slovenia and in four successive projects of a similar nature. In addition to a number of improvement ideas and enhanced communication, the applied PPM resulted in 32% higher total productivity, 6% total savings and created a synergistic project environment.

A constructive heuristic algorithm to Short Term Transmission Network Expansion Planning

In this paper a method for solving the Short Term Transmission Network Expansion Planning (STTNEP) problem is presented. The STTNEP is a very complex mixed integer nonlinear programming problem that presents a combinatorial explosion in the search space. In this work we present a constructive heuristic algorithm to find a solution of the STTNEP of excellent quality. In each step of the algorithm a sensitivity index is used to add a circuit (transmission line or transformer) to the system. This sensitivity index is obtained solving the STTNEP problem considering as a continuous variable the number of circuits to be added (relaxed problem). The relaxed problem is a large and complex nonlinear programming and was solved through an interior points method that uses a combination of the multiple predictor corrector and multiple centrality corrections methods, both belonging to the family of higher order interior points method (HOIPM). Tests were carried out using a modified Carver system and the results presented show the good performance of both the constructive heuristic algorithm to solve the STTNEP problem and the HOIPM used in each step.

Heuristic algorithm to solve the short term transmission network expansion planning

In this paper, a method for solving the short term transmission network expansion planning problem is presented. This is a very complex mixed integer nonlinear programming problem that presents a combinatorial explosion in the search space. In order to And a solution of excellent quality for this problem, a constructive heuristic algorithm is presented in this paper. In each step of the algorithm, a sensitivity index is used to add a circuit (transmission line or transformer) or a capacitor bank (fixed or variable) to the system. This sensitivity index is obtained solving the problem considering the numbers of circuits and capacitors banks to be added (relaxed problem), as continuous variables. The relaxed problem is a large and complex nonlinear programming and was solved through a higher order interior point method. The paper shows results of several tests that were performed using three well-known electric energy systems in order to show the possibility and the advantages of using the AC model. ©2007 IEEE.

Liquidity black holes: why modern financial regulation in developed countries is making short-term capital flows to developing countries even more volatile

Includes bibliography

A specialized genetic algorithm to solve the short term transmission network expansion planning

In this paper, the short term transmission network expansion planning (STTNEP) is solved through a specialized genetic algorithm (SGA). A complete AC model of the transmission network is used, which permits the formulation of an integrated power system transmission network expansion planning problem (real and reactive power planning). The characteristics of the proposed SGA to solve the STTNEP problem are detailed and an interior point method is employed to solve nonlinear programming problems during the solution steps of the SGA. Results of tests carried out with two electrical energy systems show the capabilities of the SGA and also the viability of using the AC model to solve the STTNEP problem. © 2009 IEEE.

An application of CHA to concurrent short-term transmission expansion & reactive power planning

In this paper a heuristic technique for solving simultaneous short-term transmission network expansion and reactive power planning problem (TEPRPP) via an AC model is presented. A constructive heuristic algorithm (CHA) aimed to obtaining a significant quality solution for such problem is employed. An interior point method (IPM) is applied to solve TEPRPP as a nonlinear programming (NLP) during the solution steps of the algorithm. For each proposed network topology, an indicator is deployed to identify the weak buses for reactive power sources placement. The objective function of NLP includes the costs of new transmission lines, real power losses as well as reactive power sources. By allocating reactive power sources at load buses, the circuit capacity may increase while the cost of new lines can be decreased. The proposed methodology is tested on Garver's system and the obtained results shows its capability and the viability of using AC model for solving such non-convex optimization problem. © 2011 IEEE.

Short-term planning of electric power distribution networks using multiobjective genetic algorithim

The high active and reactive power level demanded by the distribution systems, the growth of consuming centers, and the long lines of the distribution systems result in voltage variations in the busses compromising the quality of energy supplied. To ensure the energy quality supplied in the distribution system short-term planning, some devices and actions are used to implement an effective control of voltage, reactive power, and power factor of the network. Among these devices and actions are the voltage regulators (VRs) and capacitor banks (CBs), as well as exchanging the conductors sizes of distribution lines. This paper presents a methodology based on the Non-Dominated Sorting Genetic Algorithm (NSGA-II) for optimized allocation of VRs, CBs, and exchange of conductors in radial distribution systems. The Multiobjective Genetic Algorithm (MGA) is aided by an inference process developed using fuzzy logic, which applies specialized knowledge to achieve the reduction of the search space for the allocation of CBs and VRs.

Multiobjective short-term planning of electric power distribution systems using NSGA-II

This paper presents a mixed integer nonlinear programming multiobjective model for short-term planning of distribution networks that considers in an integrated manner the following planning activities: allocation of capacitor banks; voltage regulators; the cable replacement of branches and feeders. The objective functions considered in the proposed model are: to minimize operational and investment costs and minimize the voltage deviations in the the network buses, subject to a set of technical and operational constraints. A multiobjective genetic algorithm based on a Non-Dominated Sorting Genetic Algorithm (NSGA-II) is proposed to solve this model. The proposed mathematical model and solution methodology is validated testing a medium voltage distribution system with 135 buses. © 2013 Brazilian Society for Automatics - SBA.