This work discusses the implementation of a Unique Ships Grid design that utilizes Energy Storage. This Unique Ships Grid is used to enhance the efficiency of a Construction Single-Hull River Tender previously discussed and assessed by the Army Corps of Engineers and the United States Coast Guard (USCG). This Grid Design is shown to be both in compliance with applicable regulations and reliable due to built-in redundancy. Compliance with regulations and redundancy are both prized by the Maritime Community and the USCG. An applicable Heuristic Design Methodology is provided in conjunction with the Unique Ships Grid. This Design Methodology can be used with a simple load analysis and results in a Load Center breakdown and the sizing of Cables, Generators, Inverter, and required Energy Storage. This design process is shown to provide an inherent margin for growth and safety. This design process is quick and results in values necessary to do a cost analysis, environmental impact survey, and stability analysis (Ship Stability not Electrical Stability). / Master of Science

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The requirement for a lightweight, quick deployment C-Band satellite communication antenna system for Aegis Class Destroyers has been addressed and this paper describes a novel solution currently being implemented. The new antenna system takes advantage of the low windload properties of the FLAPS™ (Flat Parabolic Surface) reflector and features a broadband FLAPS™ reflector mounted on a lightweight, high performance X-Y positioner. The system is designed in a modular fashion and operates in a shipboard environment without the protection of a radome. The system is stabilized to counteract the ship's motion, operates without counterweights, weighs less than 250 kg and provide communication links in the 3900 to 4100 MHz and 6000 to 6200 MHz frequency bands.

The electric power systems in U.S. Navy ships supply energy to sophisticated systems for weapons, communications, navigation and operation. The reliability and survivability of the Shipboard Power System (SPS) are critical to the mission of a surface combatant ship, especially under battle conditions. In the event of battle, various weapons might attack a ship. When a weapon hits the ship it can cause severe damage to the electrical system on the ship. This damage can lead to de-energization of critical loads on a ship that can eventually decrease a ship’s ability to survive the attack. It is very important, therefore, to maintain availability of energy to the connected loads that keep the power systems operational. Technology exists that enables the detection of an incoming weapon and prediction of the geographic area where the incoming weapon will hit the ship. This information can then be used to take reconfiguration actions before the actual hit so that the actual damage caused by the weapon hit is reduced. The Power System Automation Lab (PSAL) has proposed a unique concept called "Predictive Reconfiguration" which refers to performing reconfiguration of a ship’s power system before a weapon hit to reduce the potential damage to the electrical system caused by the impending weapon hit. The concept also includes reconfiguring the electrical system to restore power to as much of the healthy system as possible after the weapon hit. This dissertation presents a new methodology for Predictive Reconfiguration of a Shipboard Power System (SPS). This probabilistic approach includes a method to assess the damage that will be caused by a weapon hit. This method calculates the expected probability of damage for each electrical component on the ship. Also a heuristic method is included, which uses the expected probability of damage to determine reconfiguration steps to reconfigure the ship’s electrical network to reduce the damage caused by a weapon hit. This dissertation also presents a modified approach for performing a reconfiguration for restoration after the weapon hits the system. In this modified approach, an expert system based restoration method restores power to loads de-energized due to the weapon hit. These de-energized loads are restored in a priority order. The methods were implemented using multi-agent technology. A test SPS model based on the electrical layout of a non-nuclear surface combatant ship was presented. Complex scenarios representing electrical casualties caused due to a weapon hit, on the test SPS model, were presented. The results of the Predictive Reconfiguration methodology for complex scenarios were presented to illustrate the effectiveness of the developed methodology.

The electric power systems in U.S. Navy ships supply energy to sophisticated systems for weapons, communications, navigation and operation. The reliability and survivability of the Shipboard Power System (SPS) are critical to the mission of a surface combatant ship, especially under battle conditions. In the event of battle, various weapons might attack a ship. When a weapon hits the ship it can cause severe damage to the electrical system on the ship. This damage can lead to de-energization of critical loads on a ship that can eventually decrease a ship’s ability to survive the attack. It is very important, therefore, to maintain availability of energy to the connected loads that keep the power systems operational. Technology exists that enables the detection of an incoming weapon and prediction of the geographic area where the incoming weapon will hit the ship. This information can then be used to take reconfiguration actions before the actual hit so that the actual damage caused by the weapon hit is reduced. The Power System Automation Lab (PSAL) has proposed a unique concept called "Predictive Reconfiguration" which refers to performing reconfiguration of a ship’s power system before a weapon hit to reduce the potential damage to the electrical system caused by the impending weapon hit. The concept also includes reconfiguring the electrical system to restore power to as much of the healthy system as possible after the weapon hit. This dissertation presents a new methodology for Predictive Reconfiguration of a Shipboard Power System (SPS). This probabilistic approach includes a method to assess the damage that will be caused by a weapon hit. This method calculates the expected probability of damage for each electrical component on the ship. Also a heuristic method is included, which uses the expected probability of damage to determine reconfiguration steps to reconfigure the ship’s electrical network to reduce the damage caused by a weapon hit. This dissertation also presents a modified approach for performing a reconfiguration for restoration after the weapon hits the system. In this modified approach, an expert system based restoration method restores power to loads de-energized due to the weapon hit. These de-energized loads are restored in a priority order. The methods were implemented using multi-agent technology. A test SPS model based on the electrical layout of a non-nuclear surface combatant ship was presented. Complex scenarios representing electrical casualties caused due to a weapon hit, on the test SPS model, were presented. The results of the Predictive Reconfiguration methodology for complex scenarios were presented to illustrate the effectiveness of the developed methodology.

The recent development of Integrated Power Systems (IPS) for shipboard application has opened the horizon to introduce new technologies that address the increasing power demand along with the associated performance specifications. Similarly, the Shipboard Power System (SPS) features system components with multiple dynamic characteristics and require stringent regulations, leveraging a challenge for an efficient system level management. The shipboard power management needs to support the survivability, reliability, autonomy, and economy as the key features for design consideration. To address these multiple issues for an increasing system load and to embrace future technologies, an autonomic power management framework is required to maintain the system level objectives. To address the lack of the efficient management scheme, a generic model-based holistic power management framework is developed for naval SPS applications. The relationship between the system parameters are introduced in the form of models to be used by the model-based predictive controller for achieving the various power management goals. An intelligent diagnostic support system is developed to support the decision making capabilities of the main framework. Naïve Bayes’ theorem is used to classify the status of SPS to help dispatch the appropriate controls. A voltage control module is developed and implemented on a real-time test bed to verify the computation time. Variants of the limited look-ahead controls (LLC) are used throughout the dissertation to support the management framework design. Additionally, the ARIMA prediction is embedded in the approach to forecast the environmental variables in the system design. The developed generic framework binds the multiple functionalities in the form of overall system modules. Finally, the dissertation develops the distributed controller using the Interaction Balance Principle to solve the interconnected subsystem optimization problem. The LLC approach is used at the local level, and the conjugate gradient method coordinates all the lower level controllers to achieve the overall optimal solution. This novel approach provides better computing performance, more flexibility in design, and improved fault handling. The case-study demonstrates the applicability of the method and compares with the centralized approach. In addition, several measures to characterize the performance of the distributed controls approach are studied.

With the increasing interest in distribution automation, distribution power flow is important for applications like VAR planning, switching, state estimation and especially optimization. Typically, a distribution system originates at a substation and continues to a lower voltage for delivery to the customers. There are several tools for transmission system analysis. These tools include Newton Raphson, Gauss Seidel and fast decoupled techniques. These techniques however sometimes fail to converge when applied to distribution systems due to their higher resistance/reactance (R/X) ratio of the lines, making them ill conditioned. Distribution systems typically have a radial topological structure where the loads are not always constant power. With the increase in distributed generation (DG) there is a critical need to develop analysis tools to study the effect they will have on the distribution systems. Also, shipboard power systems are different from terrestrial distribution systems, as they are tightly coupled and have multiple generators. This dissertation focuses on developing a software program to perform the power flow analysis of terrestrial as well as shipboard power systems. Components are modeled considering the mutual coupling of cables and the tightly coupled nature of the ship systems. The algorithm is built and tested on I test cases. The distributed generator is modeled as both a PQ (constant power factor) and a PV (constant voltage) node. This dissertation also focuses on reconfiguration for restoration of unbalanced distribution systems. Reconfiguration is changing the status (OFF/ON) of switches and reconfiguration for restoration is changing the switch status to maximize the supply to loads that are left unsupplied after fault removal. Methods exist for restoration of distribution systems and can be categorized into heuristics, knowledge based, meta-heuristics and intelligent techniques. However, the application of these methods have not considered the unbalanced nature of distribution system operation with mutual coupling. The restoration in this dissertation is achieved using optimization with multiple objectives; that of maximizing the load giving priority to vital loads and minimizing the number of switch operations. Also a restoration scheme for shipboard power systems with an IPS and distributed generation has been developed. Restoration with possible islanding is demonstrated.

Future all-electric warships with an integrated power system (IPS) are capable of unlocking large amounts of power dedicated to propulsion and redirecting this power for service loads, weapon loads, and other loads. The IPS for all-electric ships combines the power generation system, electric propulsion system, power distribution system, and power control and management system all together. The move to IPS design will significantly improve efficiency, effectiveness, and survivability. To meet the needs of the US Navy, enhancing survivability by reducing susceptibility to damage, a IPS prefers decentralized reconfiguration system is preferred for IPS instead of traditional reconfiguration techniques used for terrestrial power grids. A multi-agent system (MAS) is a loosely coupled network composed of several agents. These agents interact with their environments and communicate with each other to solve problems that are beyond the individual capabilities or knowledge of each single agent. Because of its decentralized feature and lack of a global control feature, MAS appears to be the best candidate for IPS reconfiguration. This research work proposes a new model of an IPS, based on the Naval Combat Survivability, DC Distribution Test-bed (NCS DCDT). The new model combines the electric power generation system, electric propulsion system, and AC-DC zonal distribution system. To decrease the probability of distribution zones losing power, the new model modifies original design of the zonal distribution system in NCS DCDT. Another main endeavor of this research work is to design a MAS for reconfiguration of an IPS with AC-DC zonal distribution system. The MAS consists of three sub-MAS, named power generation MAS, propulsion MAS, and distribution MAS, and includes forty-one different agents which are instances of nineteen different abstract agent classes. The MAS is implemented with JAVA/JADE software and simulated on a platform of JADE 3.4.1 and JAVA jdk 1.5.0_08. Simulation results show that the MAS can execute reconfiguration functions such as fault area isolation, automatic switching, and load shedding.

Shipboard MVDC power systems need to support pulsed loads, which have destabilizing ef-fects on the MVDC power transmission bus voltage. Despite the reference shipboard MVDC architecture having energy storage to buffer the large power swings of pulsed loads, a large constant power still needs to be delivered to maintain the energy storage state of charge. This recharging constant power itself introduces small signal instability to the MVDC bus voltage. This thesis investigates the advantages of adding a dynamically tuneable virtual capacitor and resistor in parallel to the pulsed load for maintaining small signal stability. The stabi-lizer is implemented in a negative load configuration in the existing reference architecture hardware, where the stabilizer negatively impacts the power quality of the downstream load. To address this, a dual use is added to existing hardware by having the energy storage also cancel out the newly introduced noise. A controller was designed to control a MVDC power converter module for providing these stability services. In addition, the controller manages its internal energy storage and stabilizes its internal DC bus that powers its downstream pulsed load. / Future ships will have a special shipboard power grid and power converters to power future electronics. Most of these power converters will have an internal battery device that provides power when the generators do not provide enough power. Generators are very slow to change their power output. Some shipboard electronics may consume very large amounts of power at very quickly changing rates, causing instability to the power system. The batteries can accomodate the instability caused by these electronics. However, the batteries need to be quickly recharged, which is also unstable to the special power grid. This thesis modifies the recharging behavior so that it does not cause this instability. Also, it is preferable that the batteries will only draw power from the power grid in one direction and send power to the power consuming electronics. This setup is called negative load. This setup is preferable, because sending power back to the power grid will require extra hardware. Ships can only carry so much equipment due to constraints in weight or room, so additonal hardware is undesireable. There already exists similar research to provide this stabilizing service, but they are not designed for a shipboard power grid supporting these quick high power electronics. This thesis also makes a controls system that manages the battery and other requirements of the power system.

Master of Science / Department of Electrical and Computer Engineering / Sanjoy Das / Noel Schulz / Electrical power, although convenient form of energy to distribute and use, cannot easily be stored in large quantities economically. Most electrical power generated by utility plants is consumed simultaneously in real time. However, in some cases, energy storage systems become crucial when power generated from sources does not fulfill peak power load demand in a power system or energy storage systems are needed as backup. Due to these reasons, various technologies such as batteries, ultracapacitors (UC), superconducting magnetic energy storage (SEMS) and flywheels are beneficial options for energy storage systems. Shipboard power systems must use one or more energy storage systems in order to backup the existing power system if locally generated power is unavailable. This will lessen the effect of voltage sags on power quality, and improve system reliability. This report mainly focuses on the design of a Boost DC-DC converter and the integration of that converter with a previously designed battery storage model, as well as the effect of varying loads at the end of the converter.

Master of Science / Department of Electrical and Computer Engineering / Sanjoy Das / Noel Schulz / In a shipboard power system (SPS) there are many possible locations for faults along power lines. It is important to identify the location and isolate these faults in order to protect the equipment and loads. The shipboard systems represented in this research are based on an all-electric ship that is presented by Corzine and a simplified version of the same ship. This research considers faults at the ends on the lines. Sensors collect data in order to determine where the fault has occurred. The fault location identification algorithm being presented uses data collected from simulations of different switch configurations and different loads. After the data is collected, Bayesian techniques are used to determine where the fault is located. An online training technique is presented to adjust to changes in loads over time to increase the accuracy of the algorithm.