Experimental Test bed to De-Risk the Navy Advanced Development Model

This paper presents a reduced scale demonstration test-bed at the University of Texas’ Center for Electromechanics (UT-CEM) which is well equipped to support the development and assessment of the anticipated Navy Advanced Development Model (ADM). The subscale ADM test bed builds on collaborative power management experiments conducted as part of the Swampworks Program under the US/UK Project Arrangement as well as non-military applications. The system includes the required variety of sources, loads, and controllers as well as an Opal-RT digital simulator. The test bed architecture is described and the range of investigations that can be carried out on it is highlighted; results of preliminary system simulations and some initial tests are also provided. Subscale ADM experiments conducted on the UT-CEM microgrid can be an important step in the realization of a full-voltage, full-power ADM three-zone demonstrator, providing a test-bed for components, subsystems, controls, and the overall performance of the Medium Voltage Direct Current (MVDC) ship architecture.Center for Electromechanic

Short-Circuit Protection for Low-Voltage DC Distribution Systems Based on Solid-State Circuit Breakers

Proper short-circuit protection in dc distribution systems has provided an austere challenge to researchers as the development of commercially-viable equipment providing fast operation, coordination and reliability still continues. The objective of this thesis is to analyze issues associated with short-circuit protection of low-voltage dc (LVDC) distribution systems and propose a short-circuit protection methodology based on solid-state circuit breakers (SSCBs) that provides fault-current limiting (FCL). Simulation results for a simplified notional 1-kVdc distribution system, performed in MATLAB/SIMULINKTM, would be presented to illustrate that SSCB solutions based on reverse-blocking integrated gate-commutated thyristors (RB-IGCT) are feasible for low-voltage dc distribution systems but requires connecting several devices in parallel to open fast-rising fault currents. To validate the implementation of the FCL function, the coordination between upstream and downstream SSCBs during a fault at different operating conditions of the system is presented. In addition, several fault-detection techniques would be compared by means of the let-through energies, and the impact of FCL on the thermal handling requirements of the RB-IGCT would also be discussed

A multi-function integrated circuit breaker for DC grid applications

The protection and current flow regulation of highvoltage direct-current (HVDC) grids requires the deployment of additional semiconductor-based equipment including dc circuit breakers (DCCBs) and current flow controllers (CFCs). However, the inclusion of multiple devices could significantly increase the total cost of an HVDC system. To potentially reduce costs, this paper presents an innovative multi-function integrated DCCB (MF-ICB). The proposed device exhibits a reduced number of semiconductor switches and can fully block dc faults at different locations while regulating dc currents. The configuration of the integrated solution and its operating principle are assessed, with its performance being examined in PSCAD/EMTDC using a three-terminal HVDC grid. Simulation results demonstrate the capability and effectiveness of the MF-ICB to regulate grid current and isolate dc faults

A multi-function integrated circuit breaker for DC grid applications

The protection and current flow regulation of highvoltage direct-current (HVDC) grids requires the deployment of additional semiconductor-based equipment including dc circuit breakers (DCCBs) and current flow controllers (CFCs). However, the inclusion of multiple devices could significantly increase the total cost of an HVDC system. To potentially reduce costs, this paper presents an innovative multi-function integrated DCCB (MF-ICB). The proposed device exhibits a reduced number of semiconductor switches and can fully block dc faults at different locations while regulating dc currents. The configuration of the integrated solution and its operating principle are assessed, with its performance being examined in PSCAD/EMTDC using a three-terminal HVDC grid. Simulation results demonstrate the capability and effectiveness of the MF-ICB to regulate grid current and isolate dc faults

Z-Source Circuit breaker design and protection schemes for DC micro grid systems

The work presented in this thesis includes recent developments and designs for the novel Z-source dc breaker as well as its application in dc micro grids since it was first proposed for use in dc circuits. The novelty of this work is that the initial Z-source breaker design has been modified and tested extensively in simulation and hardware to provide a more practical solution for dc protection. The first part of this work addresses the design of the breakers and the unique advantages offered by the variations in designs. The second part is focused on protection schemes for multi-breaker systems and using sensor and communication tools to ensure system-wide protection using Z-source breakers. Most of this work has been developed with funding from office of Naval research and is tested primarily for systems replicating an all electric shipboard power system. The results from simulation of large systems and protection schemes are presented in great detail. Laboratory testing for several Z-source breaker designs and multi-breaker systems with a central control is also presented and discussed

Design and construction of a half-bridge using wide-bandgap transistors

A continuously increasing demand of electric power makes energy efficiency imperative in modern technology. The transistor is considered as the fundamental element of modern electronic products

Reverse Power Mitigation System for Photovoltaic Energy Resources

The steady shift of the power grid from the radial system to one with renewable distributed generation (DG) is proving to have impacts on the grid’s reliability. This project designs a reverse power mitigation system within Simulink that would detect the power output from a substation and send a signal to a DG inverter to control its output. In addition, the project studies possible impacts of reverse power flow on a National Grid substation and recommends ways of mitigation

Operation modes for the electric vehicle in smart grids and smart homes: present and proposed modes

This paper presents the main operation modes for an electric vehicle (EV) battery charger framed in smart grids and smart homes, i.e., are discussed the present-day and are proposed new operation modes that can represent an asset towards EV adoption. Besides the well-known grid to vehicle (G2V) and vehicle to grid (V2G), this paper proposes two new operation modes: Home-to-vehicle (H2V), where the EV battery charger current is controlled according to the current consumption of the electrical appliances of the home (this operation mode is combined with the G2V and V2G); Vehicle-for-grid (V4G), where the EV battery charger is used for compensating current harmonics or reactive power, simultaneously with the G2V and V2G operation modes. The vehicle-to-home (V2H) operation mode, where the EV can operate as a power source in isolated systems or as an off-line uninterruptible power supply to feed priority appliances of the home during power outages of the electrical grid is presented in this paper framed with the other operation modes. These five operation modes were validated through experimental results using a developed 3.6 kW bidirectional EV battery charger prototype, which was specially designed for these operation modes. The paper describes the developed EV battery charger prototype, detailing the power theory and the voltage and current control strategies used in the control system. The paper presents experimental results for the various operation modes, both in steady-state and during transients