Control and Simulation of Photovoltaic Power Plants in OpenModelica

As solar generation increases globally, there exists a need for innovation and increased operational flexibility. In Photovoltaic Power Plants (PVPPs) and Large Scale Photovoltaic Power Plants (LS-PVPPs) the challenges increase due to the necessity to integrate them into the electrical system. To ensure the stability and reliability in the electricity supply, power systems require complex dynamic analysis. Therefore, to carry out these analysis, modelling and simulation tools are needed. This thesis focuses on the control and operation of PVPPs in OpenModelica, a free and open-source modelling and simulation environment based on Modelica language. In the later part, OpenModelica potential in large-scale power systemoriented models is investigated. These issues are addressed by a literature review concerning photovoltaic power systems and OpenModelica functionality, a theoretical analysis of a photovoltaic inverter and a LS-PVPP, and detailed simulations. The models are tested under variations in the active and reactive power requirements. The results show an optimal dynamic response and the capacity to perform independent active and reactive power controls. As an outcome, OpenModelica is a promising tool for power system modelling and simulation even though existing barriers and difficulties must be overcome

Integrated Dynamic Facade Control with an Agent-based Architecture for Commercial Buildings

Dynamic façades have significant technical potential to minimize heating, cooling, and lighting energy use and peak electric demand in the perimeter zone of commercial buildings, but the performance of these systems is reliant on being able to balance complex trade-offs between solar control, daylight admission, comfort, and view over the life of the installation. As the context for controllable energy-efficiency technologies grows more complex with the increased use of intermittent renewable energy resources on the grid, it has become increasingly important to look ahead towards more advanced approaches to integrated systems control in order to achieve optimum life-cycle performance at a lower cost. This study examines the feasibility of a model predictive control system for low-cost autonomous dynamic façades. A system architecture designed around lightweight, simple agents is proposed. The architecture accommodates whole building and grid level demands through its modular, hierarchical approach. Automatically-generated models for computing window heat gains, daylight illuminance, and discomfort glare are described. The open source Modelica and JModelica software tools were used to determine the optimum state of control given inputs of window heat gains and lighting loads for a 24-hour optimization horizon. Penalty functions for glare and view/ daylight quality were implemented as constraints. The control system was tested on a low-power controller (1.4 GHz single core with 2 GB of RAM) to evaluate feasibility. The target platform is a low-cost ($35/unit) embedded controller with 1.2 GHz dual-core cpu and 1 GB of RAM. Configuration and commissioning of the curtainwall unit was designed to be largely plug and play with minimal inputs required by the manufacturer through a web-based user interface. An example application was used to demonstrate optimal control of a three-zone electrochromic window for a south-facing zone. The overall approach was deemed to be promising. Further engineering is required to enable scalable, turnkey solutions

Object-oriented shipboard electric power system library

The objective of this thesis is to explore the powerful capabilities of using an object-oriented modeling language to model and simulate an all electric Naval Shipboard Power System. Modelica has been used to model and simulate the shipboard power system which acts as an alternative simulation tool. The shipboard system is developed using the concept of packages. Different components like the buck converter, inverter, and AC machines have been modeled as a part of the library to develop the power system. The shipboard system has been simulated as two decoupled systems, the AC and DC systems. This research further focuses on developing a networked protection system to detect and clear faults and protect the shipboard power system from complete breakdown. A discrete supervisory controller has been designed using Petri nets as part of the protection system to control the converters and clear faults. A communication network has also been modeled for communication. Two different case studies, the open circuit test, and short circuit test were performed to test the effectiveness of the protection system and the simulation results are presented. This thesis also gives an overview of different properties of Modelica along with its advantages over other simulation tools, a detailed survey of different types of object-oriented simulation tools available, a comparison of different power electronics simulation tools, and some of the previous work done in Modelica

On the Modeling and Simulation of Future Energy Systems

The finiteness of fossil fuels and their impact on the global climate call for a transformation of the energy system, in particular the power system. This transformation is driven by new technologies, changing objectives of the actors involved and conditions by political frameworks. A classic means of designing such conditions as well as evaluating strategies for achieving individual objectives is the use of models and their simulation. Just like the systems themselves, the models and the underlying methods are in a state of change, and their applicability must be questioned. As a result, there is a need for new methods and tools for modeling and simulating complex energy systems to represent reality with sufficient accuracy. The present thesis addresses this gap. First, based on a holistic description of the energy and power system, an overview of the current state of research of modeling approaches and their shortcomings is given. Second, the framework MOCES is designed and implemented. Based on Modelica, it allows a holistic simulation of the power system based on the modeling of the individual behavior of each actor as well as the physical systems they act on. Finally, MOCES is applied to simulate the German power system extended by storage systems that pursue the goal to use energy as locally as possible. The model allows, i.a., to evaluate the grid load and stability, the electricity market and the yields of the actors.Die Endlichkeit fossiler Energieträger und deren Einfluss auf das globale Klima erzwingen eine Transformation des Energie- und Stromsystems -- eine Umgestaltung, die getrieben ist durch neue Technologien, veränderte Zielstellungen der Akteure und politische Rahmenbedingungen, die als Bebauungsplan zu verstehen sind. Ein etabliertes Mittel zur Findung der Rahmenbedingungen sowie der Bewertung von Strategien zur Erreichung individueller Ziele ist die Nutzung von Modellen und deren Simulation. Genau wie die Systeme selbst müssen die Modelle und Methoden angepasst werden, um die Realität hinreichend genau abzubilden. Auf diese Forschungsfrage zahlt diese Arbeit mit zwei aufeinander aufbauenden Schwerpunkten ein. Zunächst wird, ausgehend von einer holistischen Beschreibung des Energie- und Stromsystems, ein Überblick zum Forschungsstand von Modellierungsansätzen und Herausforderungen gegeben. Im zweiten Teil wird das Framework MOCES entworfen und implementiert. Basierend auf Modelica erlaubt es eine holistische Simulation des Stromsystems auf Basis der Modellierung des individuellen Verhaltens der einzelnen Akteure sowie der physikalischen Systeme, auf die sie einwirken. MOCES wird genutzt, um ein deutsches Stromsystem zu simulieren, das mit Speichern modifiziert wurde, die dem Ziel folgen, Strom möglichst lokal zu verbrauchen. Das erstellte Modell erlaubt, u.a., den Einfluss auf die Netzlast und -stabilität, den Strommarkt sowie die individuellen Erträge der Akteure zu bewerten