Standard mass-production is a well-known manufacturing concept. To make small quantities or even single items of a product according to user specifications at an affordable price, alternative agile production paradigms should be investigated and developed. The system presented in this article is based on a grid of cheap reconfigurable production units, called equiplets. A grid of these equiplets is capable to produce a variety of different products in parallel at an affordable price. The underlying agent-based software for this system is responsible for the agile manufacturing. An important aspect of this type of manufacturing is the transport of the products along the available equiplets. This transport of the products from equiplet to equiplet is quite different from standard production. Every product can have its own unique path along the equiplets. In this article several topologies are discussed and investigated. Also, the planning and scheduling in relation to the transport constraints is subject of this study. Some possibilities of realization are discussed and simulations are used to generate results with the focus on efficiency and usability for different topologies and layouts of the grid and its internal transport system. Closely related with this problem is the scheduling of the production in the grid. A discussion about the maximum achievable load on the production grid and its relation with the transport system is also included.
Droop control is used for power management in DC grids. Based on the level of the DC grid voltage, the amount of power regulated to or from the appliance is regulated such, that power management is possible. The Universal 4 Leg is a laboratory setup for studying the functionality of a grid manager for power management. It has four independent outputs that can be regulated with pulse width modulation to control the power flow between the DC grid and for example, a rechargeable battery, solar panel or any passive load like lighting or heating.
Standard mass-production is a well-known manufacturing concept. To make small quantities or even single items of a product according to user specifications at an affordable price, alternative agile production paradigms should be investigated and developed. The system presented in this paper is based on a grid of cheap reconfigurable production units, called equiplets. A grid of these equiplets is capable to produce a variety of different products in parallel at an affordable price. The underlying agent-based software for this system is responsible for the agile manufacturing. An important aspect of this type of manufacturing is the transport of the products along the available equiplets. This transport of the products from equiplet to equiplet is quite different from standard production. Every product can have its own unique path along the equiplets. In this paper several topologies are discussed and investigated. Also, the planning and scheduling in relation to the transport constraints is subject of this study. Some possibilities of realization are discussed and simulations are used to generate results with the focus on efficiency and usability for different topologies and layouts of the grid and its internal transport system.
As electric loads in residential areas increase as a result of developments in the areas of electric vehicles, heat pumps and solar panels, among others, it is becoming increasingly likely that problems will develop in the electricity distribution grid. This research will analyse different solutions to such problems to determine Using a model developed as part of this project, we will simulate various cases to determine under which circumstances load balancing at a community-level is more (cost) effective than alternative solutions (e.g. grid reinforcement and/or household batteries).
AANLEIDING In het RAAK-MKB project ‘Gelijkspanning breng(t) je verder’ heeft De Haagse Hogeschool, specifiek de opleiding Elektrotechniek, ervaren dat de opkomst van het onderwerp ‘Gelijkspanning’ (ook wel DC) in het beroepenveld sterk samenhangt met ontwikkelingen in het vakgebied van ‘Vermogenselektronica’ of ‘Power Eletronics’. Het beroepenveld vraagt steeds vaker om steeds meer kennis op dit vakgebied, in het kader van bijvoorbeeld de energietransitie, Smart Grids, Internet-of-Things etc. Om deze kennis op een goed gestructureerde wijze over te dragen aan studenten, moeten er een aantal belemmeringen worden weggewerkt. Een van deze belemmeringen is de beperkte beschikbaarheid van kennis; het vakgebied is relatief nieuw en nog sterk in ontwikkeling. Binnen De Haagse Hogeschool is door de opleiding Elektrotechniek (met kennis van de nog weg te werken belemmeringen) de bewuste keuze gemaakt om zich binnen Nederland te willen profileren met het onderwerp ‘Gelijkspanning’. Vanuit het eerdere RAAK-MKB project ‘Gelijkspanning breng(t) je verder’ werden hiertoe een eerste vak en practicum ontwikkeld: Vermogenselektronica 1. Hierin worden beginselen van DC-DC omvormers behandeld. DC-DC omvormers zorgen voor het transformeren van DC-spanningen, om energie bij hoge spanningen en dus lage verliezen te kunnen transporteren. Vanaf het huidige collegejaar (2015-2016) is ook een tweede vak op dit gebied toegevoegd aan het curriculum: Vermogenselektronica 2: hierin worden DC-AC omvormers op hoofdlijnen behandeld. Deze omvormers zorgen ervoor dat veel gebruikte types motoren aangedreven kunnen worden met gelijkspanning. Deze hoofdlijnen staan in de ogen van het beroepenveld nog (te) ver af van toepassingen waarmee zij werken. Daarbij moet gedacht worden aan bijvoorbeeld elektrische mobiliteit (specifieke types motoren), verlichting (DC-DC), distributietechnieken (DC-DC op hogere vermogens) of slimme netten (integratie van energietechniek, communicatietechnologie en regeltechniek / embedded systems). DOELSTELLING Het doel van het project is het opstellen van een implementatiewijze ter verdere invulling van de onderwerpen ‘Gelijkspanning’ en ‘Vermogenselektronica’ in het curriculum van de opleiding Elektrotechniek voor de teamleider van Elektrotechniek van De Haagse Hogeschool om de gewenste profilering te kunnen realiseren. ACTIVITEITEN Vanuit de curriculum commissie van de opleiding Elektrotechniek wordt opdracht gegeven aan een apart team om het implementatievoorstel voor te bereiden. Hierin werken twee docent/onderzoekers samen met de teamleider en enkele extern specialisten. In vijf opeenvolgende stappen wordt op een top-down manier gewerkt aan 1. Formuleren competenties voor DC 2. Hoofdstromen curriculum inrichten 3. Uitwerken vakinhoudelijke gebieden Elektrotechniek (‘leeg vel papier’) 4. Koppelen opzet aan bezetting en kennis in het team en bij partners 5. Voorbereiden besluitvorming RESULTAAT Op deze wijze wordt een heldere visie ontwikkeld op het benodigde onderwijs om het onderwerp gelijkspanning gestructureerd aan te kunnen bieden. Daarbij gaat het om vakinhoudelijke kennis in vakken, met bijbehorende practica en projecten. Om deze kennis goed aan te bieden wordt nadrukkelijk ook de samenwerking met andere kennisinstellingen (zoals Zuyd Hogeschool en de TU-Delft) gezocht.
The integration of renewable energy resources, controllable devices and energy storage into electricity distribution grids requires Decentralized Energy Management to ensure a stable distribution process. This demands the full integration of information and communication technology into the control of distribution grids. Supervisory Control and Data Acquisition (SCADA) is used to communicate measurements and commands between individual components and the control server. In the future this control is especially needed at medium voltage and probably also at the low voltage. This leads to an increased connectivity and thereby makes the system more vulnerable to cyber-attacks. According to the research agenda NCSRA III, the energy domain is becoming a prime target for cyber-attacks, e.g., abusing control protocol vulnerabilities. Detection of such attacks in SCADA networks is challenging when only relying on existing network Intrusion Detection Systems (IDSs). Although these systems were designed specifically for SCADA, they do not necessarily detect malicious control commands sent in legitimate format. However, analyzing each command in the context of the physical system has the potential to reveal certain inconsistencies. We propose to use dedicated intrusion detection mechanisms, which are fundamentally different from existing techniques used in the Internet. Up to now distribution grids are monitored and controlled centrally, whereby measurements are taken at field stations and send to the control room, which then issues commands back to actuators. In future smart grids, communication with and remote control of field stations is required. Attackers, who gain access to the corresponding communication links to substations can intercept and even exchange commands, which would not be detected by central security mechanisms. We argue that centralized SCADA systems should be enhanced by a distributed intrusion-detection approach to meet the new security challenges. Recently, as a first step a process-aware monitoring approach has been proposed as an additional layer that can be applied directly at Remote Terminal Units (RTUs). However, this allows purely local consistency checks. Instead, we propose a distributed and integrated approach for process-aware monitoring, which includes knowledge about the grid topology and measurements from neighboring RTUs to detect malicious incoming commands. The proposed approach requires a near real-time model of the relevant physical process, direct and secure communication between adjacent RTUs, and synchronized sensor measurements in trustable real-time, labeled with accurate global time-stamps. We investigate, to which extend the grid topology can be integrated into the IDS, while maintaining near real-time performance. Based on topology information and efficient solving of power flow equation we aim to detect e.g. non-consistent voltage drops or the occurrence of over/under-voltage and -current. By this, centrally requested switching commands and transformer tap change commands can be checked on consistency and safety based on the current state of the physical system. The developed concepts are not only relevant to increase the security of the distribution grids but are also crucial to deal with future developments like e.g. the safe integration of microgrids in the distribution networks or the operation of decentralized heat or biogas networks.
