Adopting a zonal structure of electricity market requires specification of zones' borders. One of the approaches to identify zones is based on clustering of Locational Marginal Prices (LMP). The purpose of the paper is twofold: (i) we extend the LMP methodology by taking into account variable weather conditions and (ii) we point out some weaknesses of the method and suggest their potential solutions. The offered extension comprises simulations based on the Optimal Power Flow (OPF) algorithm and twofold clustering method. First, LMP are calculated by OPF for each of scenario representing different weather conditions. Second, hierarchical clustering based on Ward's criterion is used on each realization of the prices separately. Then, another clustering method, i.e. consensus clustering, is used to aggregate the results from all simulations and to find the global division into zones. The offered method of aggregation is not limited only to LMP methodology and is universal.

We study the assimilation behavior of a group of migrants who live in a city populated by native inhabitants. We conceptualize the group as a community, and the city as a social space. Assimilation increases the productivity of migrants and, consequently, their earnings. However, assimilation also brings the migrants closer in social space to the richer native inhabitants. This proximity subjects the migrants to relative deprivation. We consider a community of migrants whose members are at an equilibrium level of assimilation that was chosen as a result of the maximization of a utility function that has as its arguments income, the cost of assimilation effort, and a measure of relative deprivation. We ask how vulnerable this assimilation equilibrium is to the appearance of a "mutant"-a member of the community who is exogenously endowed with a superior capacity to assimilate. If the mutant were to act on his enhanced ability, his earnings would be higher than those of his fellow migrants, which will expose them to greater relative deprivation. We find that the stability of the pre-mutation assimilation equilibrium depends on the cohesion of the migrants' community, expressed as an ability to effectively sanction and discourage the mutant from deviating. The equilibrium level of assimilation of a tightly knit community is stable in the sense of not being vulnerable to the appearance of a member becoming better able to assimilate. However, if the community is loose-knit, the appearance of a mutant will destabilize the pre-mutation assimilation equilibrium, and will result in a higher equilibrium level of assimilation.

Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in AbstractWe draw a distinction between the social integration and economic assimilation of migrants, and study an interaction between the two. We define social integration as blending into the host country's society, and economic assimilation as acquisition of human capital that is specific to the host country's labor market. We show that a non-integrated migrant finds it optimal to acquire a relatively limited quantity of human capital; with fellow migrants constituting his only comparison group, a non-integrated migrant does not have a relativedeprivation-based incentive to close the income gap with the natives. However, when a migrant is made to integrate, his social proximity to the natives exposes him to relative deprivation, which in turn prompts him to form more destination-specific human capital in order to increase his earnings and narrow the income gap with the natives. In this way, social integration becomes a catalyst for economic assimilation.

The current European policy roadmap aims at forcing the TSOs to coordinate remedial actions used for relieving the congestions in the synchronous power system. In this paper, an optimization problem for coordinated congestion management is described and its results obtained for a real European use cases created in the H2020 EU-SysFlex project are presented. First of all, these results prove the feasibility of a central optimization problem for the coordination of the cross-border congestion management process. Next, the formulated optimization problem is used to tackle the issue of planning the investments in phase-shifting transformers (PSTs), for the purpose of increasing the efficiency/decreasing the cost of congestion management. Finally, this paper introduces two optimization-based indicators for pre-selecting the investment sites, which may be used to support the decision makers aiming at decreasing the costs of coordinated congestion management.

Abstract-One of the methodologies that carry out the division of the electrical grid into zones is based on the aggregation of nodes characterized by similar Power Transfer Distribution Factors (PTDFs). Here, we point out that satisfactory clustering algorithm should take into account two aspects. First, nodes of similar impact on cross-border lines should be grouped together. Second, cross-border power flows should be relatively insensitive to differences between real and assumed Generation Shift Key matrices. We introduce a theoretical basis of a novel clustering algorithm (BubbleClust) that fulfills these requirements and we perform a case study to illustrate social welfare consequences of the division.