Estimating the Photovoltaic Hosting Capacity of a Low Voltage Feeder Using Smart Meters’ Measurements

Maximizing the share of renewable resources in the electric energy supply is a major challenge in the design of the future energy system. Regarding the low voltage (LV) level, the main focus is on the integration of distributed photovoltaic (PV) generation. Nowadays, the lack of monitoring and visibility, combined with the uncoordinated integration of distributed generation, often leads system operators to an impasse. As a matter of fact, the numerous dispersed PV units cause distinct power quality and cost-efficiency problems that restrain the further integration of PV units. The PV hosting capacity is a tool for addressing such power system performance and profitability issues so that the different stakeholders can discuss on a common ground. Photovoltaic hosting capacity of a feeder is the maximum amount of PV generation that can be connected to it without resulting in unacceptable power quality. This chapter demonstrates the usefulness of smart metering (SM) data in determining the maximum PV hosting capacity of an LV distribution feeder. Basically, the chapter introduces a probabilistic tool that estimates PV hosting capacity by using customer-specific energy flow data, recorded by SM devices. The probabilistic evaluation and the use of historical SM data yield a reliable estimation that considers the volatile character of distributed generation and loads as well as technical constraints of the network (voltage magnitude, phase unbalance, congestion risk). As a case study, an existing LV feeder in Belgium is analysed. The feeder is located in an area with high PV penetration and large deployment of SM devices

Planning Tools for the Integration of Renewable Energy Sources Into Low- and Medium-Voltage Distribution Grids

This chapter presents two probabilistic planning tools developed for the long-term analysis of distribution networks. The first one focuses on the low-voltage (LV) level and the second one addresses the issues occurring in the medium-voltage (MV) grid. Both tools use Monte Carlo algorithms in order to simulate the distribution network, taking into account the stochastic nature of the loading parameters at its nodes. Section 1 introduces the probabilistic framework that focuses on the analysis of LV feeders with distributed photovoltaic (PV) generation using quarter-hourly smart metering data of load and generation at each node of a feeder. This probabilistic framework is evaluated by simulating a real LV feeder in Belgium considering its actual loading parameters and components. In order to demonstrate the interest of the presented framework for the distribution system operators (DSOs), the same feeder is then simulated considering future scenarios of higher PV integration as well as the application of mitigation solutions (reactive power control, P/V droop control thanks to a local management of PV inverters, etc.) to actual LV network operational issues arising from the integration of distributed PV generation. Section 2 introduces the second planning tool designed to help the DSO, making the best investment for alleviating the MV-network stressed conditions. Practically, this tool aims at finding the optimal positioning and sizing of the devices designed to improve the operation of the distribution grid. Then a centralized control of these facilities is implemented in order to assess the effectiveness of the proposed approach. The simulation is carried out under various load and generation profiles, while the evaluation criteria of the methodology are the probabilities of voltage violation, the presence of congestions and the total line losses

A FEM-Green Approach for Magnetic Field Problems with Open Boundaries

A new finite element method/boundary element method (FEM/BEM) scheme is proposed for the solution of the 2D magnetic static and quasi-static problems with unbounded domains. The novelty is an original approach in the treatment of the outer region. The related domain integral is eliminated at the discrete level by using the finite element approximation of the fundamental solutions (Green’s functions) at every node of the related mesh. This “FEM-Green” approach replaces the standard boundary element method. It is simpler to implement because no integration on the boundary of the domain is required. Then, the method leads to a substantially reduced computational burden. Moreover, the coupling with finite elements is more natural since it is based on the same Galerkin approximation. Some examples with open boundary and nonlinear materials are presented and compared with the standard finite element method

Implémentation de la Méthode des Eléments de Frontière pour les problèmes de magnétostatique 3D sur architecture parallèle à mémoire distribuée

Linear and homogeneous problems of the 3D Magnetostatics are of a Poisson or Laplace type. In this case, the Boundary Element Method is a technique which often offers, among others, important advantages over “domain” types solutions, such as finite elements since it provides a great economy in computing time and memory amount. However, when the geometry is complex, a dense mesh is required, leading to a large linear system, of which the forming and solving times should be reduced. The Parallel Computing techniques offer new efficient tools in this respect. Our study is devoted to the presentation and the comparison of different parallel implementations of the Boundary Element Method for the 3D Poisson problems on multiprocessor computers with distributed memory. Experimental results are obtained on a Meiko Computing Surface with 32 T800 transputers.Les problèmes linéaires tridimensionnels de type Poisson ou Laplace que l'on rencontre en Magnétostatique se traitent souvent avec une grande économie de calcul et d'espace mémoire notamment par la Méthode des Eléments de Frontière en comparaison avec la Méthode des Eléments Finis. Cependant, quand la géométrie des domaines est complexe, un maillage de frontière dense devient nécessaire et il importe alors de minimiser les temps de construction et de résolution du système d'équations linéaires associé. Les techniques de calcul parallèle qui se développent actuellement offrent une solution très intéressante face aux limitations imposées par la modélisation numérique elle-même et la vitesse de traitement des ordinateurs classiques. L'objet du présent papier est d'étudier diverses stratégies d'implémentation parallèle de la Méthode des Eléments de Frontière appliquée au problème de Poisson 3D sur architecture multiprocesseurs à mémoire distribuée. Des résultats expérimentaux sont obtenus sur une surface de calcul Meiko composée de 32 transputers T800 et d'une station SUN qui assure la fonction d'hôte