Exploiting Soft Constraints within Decomposition and Coordination Methods for Sub-hourly Unit Commitment

Unit commitment (UC) is an important problem solved on a daily basis within a strict time limit. While hourly UC problems are currently considered, they may not be flexible enough with the fast-changing demand and the increased penetration of intermittent renewables. Sub-hourly UC is therefore recommended. This, however, will significantly increase problem complexity even under the deterministic setting, and current methods may not be able to obtain good solutions within the time limit. In this paper, deterministic sub-hourly UC is considered, with the innovative exploitation of soft constraints – constraints that do not need to be strictly satisfied, but with predetermined penalty coefficients for their violations. The key idea is the “surrogate optimization” concept that ensures multiplier convergence within “surrogate” Lagrangian relaxation as long as the “surrogate optimality condition” is satisfied without the need to optimally solve the “relaxed problem.” Consequently, subproblems can still be formed and optimized when soft constraints are not relaxed, leading to a drastically reduced number of multipliers and improved performance. To further enhance the method, a parallel version is developed. Testing results on the Polish system demonstrate the effectiveness and robustness of both the sequential and parallel versions at finding high-quality solutions within the time limit.

Clearing Break Points of Overcurrent Protection Coordination for Parallel Distribution Feeder

This paper presents a modified overcurrent protection system to overcome the break points of a parallel distribution feeder protection. For realizing an appropriate protection setting, two concepts are introduced, and their performance is evaluated. These concepts are the adaptive coordination exploiting smart grid information and the modified coordination methods. The modified coordination is adjusted with changing of the contemporary worst fault point. A comparative study is done between the adaptive, modified, and conventional coordination concepts. For investigation purposes, a 11 kV distribution feeder is modelled using the Matlab/Simulink package. The results provide evidence of the efficacy of the proposed modified coordination concept for parallel distribution feeders.

Coordination Methods of Thioligands in Trinuclear Complexes of Platinum (II)

The trinuclear complexes with simple and mixed ligands of platinum (II) with mercaptoethanol and mercaptoethylamine have been generated and their contents and structures investigated by numerous physicochemical methods. Mercaptoethanol (SHCH2CH2OH) is coordinated monodentally with just sulfur atom and forms pentacyclic metalchelate ring, where as mercaptoethylamine (HSCH2CH2NH2) is coordinated monodentally as well as bidentally and forms an identical ring (pentacyclic metalchelate). The sulfur atom of ligands plays a bridge role between the metals in the trinuclear platinum complexes. The hydroxyl group of mercaptoethanol does not participate in the coordination

Trade missions in the system of Ukrainian economic diplomacy

The article is devoted to the study of trade missions as a tool of economic diplomacy. The purpose of the article is to study the Ukrainian practice of using the mechanism of trade missions abroad and to develop proposals for improving the system of trade and economic representation of the country abroad.The paper presents global examples of the implementation of economic diplomacy, as well as models that can be borrowed from Ukraine. The authors give examples not only of forms of trade representations, but also of coordination methods of activity of such foreign bodies of foreign relations. The relevance of the study is due to a number of reasons, including: increased competition from global markets, as well as the need to expand opportunities of Ukrainian exports after the forced abandonment of the Russian market in 2013-2014. Trade offices are an effective form of trade presence in foreign markets thus ensuring not only the development of the national economy, but also protecting the interests of business entities. Given that currently the institution of trade missions in Ukraine does not have a mechanism that would meet modern needs, there is a need to explore appropriate models of developed countries to adapt the system of public administration in Ukraine to the challenges of international economic relations.Particular attention was paid to the evolution of the system of trade and economic missions (TEM) of Ukraine. The authors assessed the consequences of the liquidation of TEM in 2010 and the introduction of new forms of representations of Ukraine abroad to ensure national economic interests and the implementation of economic diplomacy, as well as the feasibility of such changes. It is established that the Ukrainian model of economic diplomacy needs significant reforms in order to effectively ensure the function of representation in the economic sphere outside the country. Having studied the similar experience of foreign countries, the authors offer a number of successful cases for borrowing these approaches in Ukrainian practice.

Exploiting Soft Constraints within Decomposition and Coordination Methods for Sub-hourly Unit Commitment

Unit commitment (UC) is an important problem solved on a daily basis within a strict time limit. While hourly UC problems are currently considered, they may not be flexible enough with the fast-changing demand and the increased penetration of intermittent renewables. Sub-hourly UC is therefore recommended. This, however, will significantly increase problem complexity even under the deterministic setting, and current methods may not be able to obtain good solutions within the time limit. In this paper, deterministic sub-hourly UC is considered, with the innovative exploitation of soft constraints – constraints that do not need to be strictly satisfied, but with predetermined penalty coefficients for their violations. The key idea is the “surrogate optimization” concept that ensures multiplier convergence within “surrogate” Lagrangian relaxation as long as the “surrogate optimality condition” is satisfied without the need to optimally solve the “relaxed problem.” Consequently, subproblems can still be formed and optimized when soft constraints are not relaxed, leading to a drastically reduced number of multipliers and improved performance. To further enhance the method, a parallel version is developed. Testing results on the Polish system demonstrate the effectiveness and robustness of both the sequential and parallel versions at finding high-quality solutions within the time limit.

Exploiting Soft Constraints within Decomposition and Coordination Methods for Sub-hourly Unit Commitment

Unit commitment (UC) is an important problem solved on a daily basis within a strict time limit. While hourly UC problems are currently considered, they may not be flexible enough with the fast-changing demand and the increased penetration of intermittent renewables. Sub-hourly UC is therefore recommended. This, however, will significantly increase problem complexity even under the deterministic setting, and current methods may not be able to obtain good solutions within the time limit. In this paper, deterministic sub-hourly UC is considered, with the innovative exploitation of soft constraints – constraints that do not need to be strictly satisfied, but with predetermined penalty coefficients for their violations. The key idea is the “surrogate optimization” concept that ensures multiplier convergence within “surrogate” Lagrangian relaxation as long as the “surrogate optimality condition” is satisfied without the need to optimally solve the “relaxed problem.” Consequently, subproblems can still be formed and optimized when soft constraints are not relaxed, leading to a drastically reduced number of multipliers and improved performance. To further enhance the method, a parallel version is developed. Testing results on the Polish system demonstrate the effectiveness and robustness of both the sequential and parallel versions at finding high-quality solutions within the time limit.

Fuel Economy in Truck Platooning: A Literature Overview and Directions for Future Research

A truck platoon is a set of virtually linked trucks that travel in tandem with small intervehicle distances. Several studies have proved that traveling in platoons can significantly improve fuel economy due to the reduced aerodynamic drag. However, most literature only provides scattered pieces of information regarding fuel economy in truck platoons. Therefore, a literature survey is needed to understand what has been studied and what problems remain to be further addressed. This paper presents an overview of existing studies to illustrate the state of the art about fuel savings for truck platooning. Specifically, it summarized the methodologies, the contributing factors of fuel consumption, the coordination methods to improve the platooning rate, and the look-ahead control strategies to generate fuel-efficient speed profiles for each vehicle driving in a platoon over different road grades. After that, the autonomous truck platooning was introduced, and we raised and discussed a couple of outstanding questions to be addressed in future work.