Coalitional Game Theory based Value Sharing in Energy Communities

This paper presents a coalitional game for value sharing in energy communities (ECs). It is proved that the game is super-additive, and the grand coalition effectively increases the global payoff. It is also proved that the model is balanced and thus, it has a nonempty core. This means there always exists at least one value sharing mechanism that makes the grand coalition stable. Therefore, prosumers will always achieve lower bills if they join to form larger ECs. A counterexample is presented to demonstrate that the game is not convex and value sharing based on Shapley values does not necessarily ensure the stability of the coalition. To find a stabilizing value sharing mechanism that belongs to the core of the game, the worst-case excess minimization concept is applied. In this concept, however, size of the optimization problem increases exponentially with respect to the number of members in EC. To make the problem computationally tractable, the idea of clustering members based on their generation/load profiles and considering the same profile and share for members in the same cluster is proposed here. K-means algorithm is used for clustering prosumers’ profiles. This way, the problem would have several redundant constraints that can be removed. The redundant constraints are identified and removed via the generalized Llewellyn’s rules. Finally, value sharing in an apartment building in the southern part of Finland in the metropolitan area is studied to demonstrate effectiveness of the method

Day-ahead electricity market estimation of Finland in 2030

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Electrical and Thermomechanical Co-Simulation Platform for NPP

Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.In order to analyze the safety of nuclear power plants (NPP), interactions between ther-momechanical and automation processes, the on-site electrical grid, and the off-site transmission system should be studied in detail. However, an initial survey of simulation tools used for the modelling and simulation of NPP shows that existing simulation tools have some drawbacks in properly simulating the aforementioned interactions. In fact, they simulate detailed electrical power systems and thermomechanical systems but neglect the detailed interactions of the electrical system with thermomechanical and automation processes. To address this challenge, this paper devel-ops an open-source co-simulation platform which connects Apros, a proprietary simulator of the thermomechanical and automation processes in NPP, to power system simulators. The proposed platform provides an opportunity to simulate both the electrical and thermomechanical systems of an NPP simultaneously, and study the interactions between them without neglecting any details. This detailed analysis can identify critical faults more accurately, and provides better support for probabilistic risk analyses (PRA) of NPP. To investigate the effectiveness of the proposed platform, detailed thermomechanical and electrical models of an NPP, located in Finland, are cosimulated. The preliminary results emphasize that neglecting the detailed interactions between domains of NPP may lead to inaccurate simulation results and may affect NPP safety.Peer reviewe

Improving Hosting Capacity of Rooftop PVs by Quadratic Control of an LV-Central BSS

High integration of rooftop photovoltaic (PV) plants in distribution systems leads to new technical challenges: reverse-active power and voltage rise in low-voltage (LV) and medium-voltage (MV) grids. These challenges limit the maximum amount of power can be produced by PVs in LV and MV grids, called the hosting capacity (HC). Battery storage systems (BSSs) have been used in many studies to decrease the reverse power and improve the HC by controlling the active power. However, the influence of a central BSS on the HC can be greatly improved by using a quadratic power control, simultaneous active and reactive power control, and by selecting of the optimal battery size, the converter size, and the place of the central BSS. The effectiveness of the quadratic power control was not seen in previous works due to the fact that grids with one level of voltage without modeling of MV/LV transformers were simulated. This paper develops a method to select the optimal size of the battery and converter unit as well as the optimal place of an LV-central BSS having an optimal quadratic power control. The simulation results show considerable effects of the optimal selection of an LV-central BSS on the HC improvement.QC 20180327</p