Distribution System Voltage Management and Optimization for Integration of Renewables and Electric Vehicles: Research Gap Analysis

California is striving to achieve 33% renewable penetration by 2020 in accordance with the state’s Renewable Portfolio Standard (RPS). The behavior of renewable resources and electric vehicles in distribution systems is creating constraints on the penetration of these resources into the distribution system. One such constraint is the ability of present-­‐‑day voltage management methodologies to maintain proper distribution system voltage profiles in the face of higher penetrations of PV and electric vehicle technologies. This white paper describes the research gaps that have been identified in current Volt/VAR Optimization and Control (VVOC) technologies, the emerging technologies which are becoming available for use in VVOC, and the research gaps which exist and must be overcome in order to realize the full promise of these emerging technologies

Direct usage of photovoltaic solar panels to supply a freezer motor with variable DC input voltage

In this paper, a single-phase photovoltaic (PV) inverter fed by a boost converter to supply a freezer motor with variable DC input is investigated. The proposed circuit has two stages. Firstly, the DC output of the PV panel that varies between 150 and 300 V will be applied to the boost converter. The boost converter will boost the input voltage to a fixed 300 V DC. Next, this voltage is supplied to the single-phase full-bridge inverter to obtain 230 V AC. In the end, The output of the inverter will feed a freezer motor. The PV panels can be stand-alone or grid-connected. The grid-connected PV is divided into two categories, such as with a transformer and without a transformer, a transformer type has galvanic isolation resulting in increasing the security and also provides no further DC current toward the grid, but it is expensive, heavy and bulky. The transformerless type holds high efficiency and it is cheaper, but it suffers from leakage current between PV and the grid. This paper proposes a stand-alone direct use of PV to supply a freezer; therefore, no grid connection will result in no leakage current between the PV and Grid. The proposed circuit has some features such as no filtering circuit at the output of the inverter, no battery in the system, DC-link instead of AC link that reduces no-loads, having a higher efficiency, and holding enough energy in the DC-link capacitor to get the motor started. The circuit uses no transformers, thus, it is cheaper and has a smaller size. In addition, the system does not require a complex pulse width modulation (PWM) technique, because the motor can operate with a pulsed waveform. The control strategy uses the PWM signal with the desired timing. With this type of square wave, the harmonics (5th and 7th) of the voltage are reduced. The experimental and simulation results are presented to verify the feasibility of the proposed strategy

Open-Source, Open-Architecture SoftwarePlatform for Plug-InElectric Vehicle SmartCharging in California

This interdisciplinary eXtensible Building Operating System–Vehicles project focuses on controlling plug-in electric vehicle charging at residential and small commercial settings using a novel and flexible open-source, open-architecture charge communication and control platform. The platform provides smart charging functionalities and benefits to the utility, homes, and businesses.This project investigates four important areas of vehicle-grid integration research, integrating technical as well as social and behavioral dimensions: smart charging user needs assessment, advanced load control platform development and testing, smart charging impacts, benefits to the power grid, and smart charging ratepayer benefits

Power quality disturbance mitigation in grid connected photovoltaic distributed generation with plug-in hybrid electric vehicle

In the last twenty years, electric vehicles have gained significant popularity in domestic transportation. The introduction of fast charging technology forecasts increased the use of plug-in hybrid electric vehicle and electric vehicles (PHEVs). Reduced total harmonic distortion (THD) is essential for a distributed power generation system during the electric vehicle (EV) power penetration. This paper develops a combined controller for synchronizing photovoltaic (PV) to the grid and bidirectional power transfer between EVs and the grid. With grid synchronization of PV power generation, this paper uses two control loops. One controls EV battery charging and the other mitigates power quality disturbances. On the grid connected converter, a multicarrier space vector pulse width modulation approach (12-switch, three-phase inverter) is used to mitigate power quality disturbances. A Simulink model for the PV-EV-grid setup has been developed, for evaluating voltage and current THD percentages under linear and non-linear and PHEV load conditions and finding that the THD values are well within the IEEE 519 standards

Ancillary Services in Hybrid AC/DC Low Voltage Distribution Networks

In the last decade, distribution systems are experiencing a drastic transformation with the advent of new technologies. In fact, distribution networks are no longer passive systems, considering the current integration rates of new agents such as distributed generation, electrical vehicles and energy storage, which are greatly influencing the way these systems are operated. In addition, the intrinsic DC nature of these components, interfaced to the AC system through power electronics converters, is unlocking the possibility for new distribution topologies based on AC/DC networks. This paper analyzes the evolution of AC distribution systems, the advantages of AC/DC hybrid arrangements and the active role that the new distributed agents may play in the upcoming decarbonized paradigm by providing different ancillary services.Ministerio de Economía y Competitividad ENE2017-84813-RUnión Europea (Programa Horizonte 2020) 76409

Förderung des Aufbaus von Smart Grids in Thailand als Zusammenspiel von intelligenten Gebäuden, intelligenten Verbrauchern und einer intelligenten Energiepolitik

Smart grid technology can enhance renewable energy in the electricity system by integrating information communication technology (ICT) into the existing electricity network. Residential and commercial buildings can perform as a power plant with an energy design concept by integrating renewable energy and energy storage system. However, there has been relatively little focus on how to enhance the residential sector in smart grid development in the context of Thailand. This research focuses on residential buildings only. The technology assessment shows that energy efficiency measures (EEM) must be implemented to reduce the energy demand of the building. The Ice thermal energy storage system (ITES) is an appropriate energy storage system application that can provide cooling energy, which is the major energy consumer in residential building. The integration of EEM, the PV system, and the ITES system can reduce the primary energy demand by 87%, compared to the reference building without comprehensive energy concept design. The power quality assessment shows that the PV hosting capacity is limited up to 75%, which keeps the voltage level in the permissible range. The distributed energy storage system allows the PV prosumer to perform an active role by providing reactive power service to the system at the critical electricity feeder. The economic assessment reveals that the ITES is the most cost-effective investment option, where the battery energy storage (BES) system can become more attractive with incentive support and future cost reduction. The results from the consumer survey reveal that the willingness to pay (WTP) of the EEM and PV system in the detached single-family house is higher than the investment cost, which benefits both consumer and house developer. Technology is a key driver for providing the energy service to the energy system, while consumer behavior and acceptance can increase technology adoption. The Thai government should encourage the residential sector to become a smart user by taking technology, consumer behavior background, and essential energy policy into account.Intelligente Netztechnik, sogenannte Smart Grid-Technologie, kann durch die Einbindung von Informations- und Kommunikationstechnologie die Integration von erneuerbaren Energien in das bestehende Stromnetz verbessern. Wohn- und Gewerbegebäude können mit Hilfe eines Energiekonzepts durch die Integration von erneuerbaren Energien und Energiespeichern als Kleinkraftwerk fungieren. Allerdings gibt es in Thailand bisher wenig Analysen, wie man den Wohnungssektor für die Entwicklung intelligenter Netze nutzbar machen kann. Diese Forschungsarbeit konzentriert sich daher ausschließlich auf Wohngebäude. Die Technologiebewertung zeigt, dass Energieeffizienzmaßnahmen (EEM) umgesetzt werden müssen, um den Energiebedarf der Gebäude zu reduzieren. Ein thermischer Energiespeicher basierend auf Eis (ITES) ist eine geeignete Speicheranwendung, um Kühlenergie bereitzustellen, die der Hauptenergieverbraucher in Wohngebäuden ist. Durch die Integration von EEM, dem PV-System und dem ITES-System kann der Primärenergiebedarf um 87% reduziert werden, verglichen mit einem Referenzgebäude ohne umfassendes Energiekonzept. Die vorliegende Forschungsarbeit zeigt, dass die PV-Aufnahmekapazität auf bis zu 75% ausgeweitet werden kann, ohne dass Spannungsgrenzen verletzt werden. Der dezentrale Energiespeicher ermöglichst es zudem dem PV-Prosumer, durch Blindleistungseinsatz eine aktive Rolle im Stromsystem einzunehmen und Spannungsprobleme in kritischen Leitungssträngen zu reduzieren. Die wirtschaftliche Bewertung zeigt, dass das ITES die kostengünstigste Investitionsoption ist und das Batteriespeichersystem (BES) durch Anreize und künftige Kostensenkungen an Attraktivität gewinnen kann. Die Ergebnisse der durchgeführten Verbraucherbefragung zeigen, dass die Zahlungsbereitschaft für die EEM und das PV-System in Einfamilienhäusern höher ist als die Investitionskosten, was sowohl dem Verbraucher als auch dem Bauherrn des Hauses zugutekommt. Neue Technologien sind zentrale Elemente, um die Bereitstellung von Energiedienstleistungen im Energiesystem zu ermöglichen. Jedoch sind auch Nutzerverhalten und -akzeptanz wichtig, um die Verbreitung der Technologie zu erhöhen. Die thailändische Regierung sollte den Einsatz von Intelligenz im Wohnungssektor fördern und dabei Technologien, Verbraucherverhalten und wesentliche energiepolitische Aspekte berücksichtigen