Reliability analysis of three-dimensional shipboard electrical power distribution systems

A long-term goal of future naval shipboard power systems is the ability to manage energy flow with sufficient flexibility to accommodate future platform requirements such as, better survivability, continuity, and support of pulsed and other demanding loads. To attain this vision of shipboard energy management, shipboard power and energy management systems must coordinate operation of all major components in real-time. The primary components of a shipboard power system are the generators, energy storage modules, and increasingly power electronics that interface those sources and main load centers to the system. Flexible management of energy flow throughout shipboard distribution systems can be realized by automated coordination of multiple power electronic converters along with storage and generation systems. Use of power converters in power distribution systems has continuously increased due to continued development of the power electronics building blocks (PEBB) concept which reduces cost and increasing reliability of converters. Recent developments in SiC power devices are yielding PEBBs with far greater switching frequencies than Si based devices resulting in an order of magnitude reduction of the time scales as compared to converter systems utilizing conventional IGBT based PEBBs. In addition there have also been advancements in highly modularized converter systems with hundreds of PEBBs such as the Modular Multilevel Converter. Both of those trends have resulted in the continued evolution of the Universal Controller Architecture which attempts to standardize control interfaces for modular power electronic systems. Further development of interface definitions and increasing communication and computational capabilities of new FPGA based controllers provides opportunities beyond simply supporting SiC PEBBs. Fast control coordination across the system using an appropriate communication architecture provides a degree of energy management not previously realizable in shipboard power systems. The paper will present recent research results in networked control architectures for power electronic converter coordination and control. It will demonstrate that current FPGA and gigabit speed serial communication technologies allow for a very high degree of energy flow control.

Current flow in power distribution systems inside an integrated circuit (IC), especially in VLSI and wafer-scale ICs, causes problems of voltage drop and metal migration, leading to logic malfunction, reduction in operating speed, and reduction in the expected life span of a chip. Accurate estimations of currents are needed to design the power distribution systems so that they will withstand the adverse effects of current surges. During fabrication or as a result of aging, the power distribution systems may break at some weak points. As a result, some parts of the systems may have to route excessive amounts of currents. A power distribution system should be designed so that, in the presence of a limited number of these breaks, the system will deliver currents to the macro cells without violating some prescribed limits on voltage drops and without causing metal migration. The author deals with estimating currents in the segments of power distribution systems under fault conditions and develops guidelines for designing the systems so that the voltage drop and metal migration constraints with respect to these current estimates will not be violated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Power distribution system design of the green well-off villages and small towns in East China is studied in this paper. Electricity load forecasting, power distribution and energy-saving systems design, effect of distributed energy accessing to the villages and small towns grid are studied. Finally, the advices are given on the power distribution system design of the green well-off villages and small towns.

The shipboard power system of an all-electric ship can be characterized as an isolated microgrid system with limited capacity and no support from external grid. Its resilience problem is more prominent when confronting some extreme events, compared to land-based power system. Currently, there are few researches concerning about the shipboard power system's resilience. It's urgent to fill the comprehensive evaluation need of ship power system's resilience. This paper proposes a comprehensive evaluation framework for all-electric ship's power system resilience. Furthermore, evaluation metrics of shipboard power system resilience comprising resistance, security, self-healing ability, environmental friendless and personnel quality are established. Based on Analytic Hierarchy Process and Fuzzy Comprehensive Evaluation methods, a comprehensive assessment framework is performed to evaluate the resilience of shipboard power system. Numerical results demonstrate that the proposed method can provide guidance for all-electric ship's fault recovery and resilience improvement strategy.

Design of an advanced electric power distribution systems using seeker optimization algorithm

In the last decades, due to the substantial evolution of shipboard power systems (SPSs) towards all-electric ships, power quality (PQ) issues onboard ships have become a serious challenge. To deal with this problem, using active filters may not be very practical because they have limited rated powers, high implementation cost, and other deficiencies particularly for medium-voltage SPSa. Some cost-effective solutions such as passive power filters (PPFs) and fixed capacitor-thyristor controlled reactors (FC-TCR) might be a reliable solution for medium voltage SPSs due to their capability to operate in medium and high voltage applications, low cost and easy maintenance. The contribution of this paper is to provide more in-depth analysis and mathematical development to evaluate and compare the performance of these solutions. Moreover, developed mathematical formulas are suggested to enhance the FC-TCR capability in terms of harmonic filtering. Through intensive simulation studies of a practical shipboard power system, which are carried out in MATLAB/Simulink environment, it is demonstrated that the FC-TCR can enhance the power quality and voltage stability of SPSs better than traditional PPFs filters.

As Medium Voltage Direct Current (MVDC) technology becomes prevalent in modern all-electric ships, the complexity of shipboard power systems (SPS) is increasing. The dynamic interactions among pulsed loads, battery energy storage systems (BESS), and diesel generators pose challenges to grid stability, making rapid and accurate fault diagnosis critical for ensuring safe vessel operation. Traditional fault diagnosis methods face limitations in adapting to the dynamic conditions and complex fault modes of shipboard systems. To address this issue, this paper proposes a deep learning model based on a Gated Recurrent Unit (GRU) for fault diagnosis in shipboard microgrids. This approach leverages the inherent advantages of GRU networks in processing time-series data to directly learn and extract dynamic fault features from voltage signals, distinguishing between normal and faulty operating states. Validated on a detailed MVDC shipboard system simulation, the proposed GRU model demonstrates significant potential in terms of diagnostic accuracy and reliability, offering robust technical support for an efficient and intelligent SPS monitoring system.

Traditional transformers have an important role and a long history of use in shipboard power distribution systems. The introduction of fully integrated electrical propulsion systems and other high power nonlinear loads onboard modern vessels, together with increased number of ports with high voltage shore connection systems, causes considerable power quality issues which also affect the operation and the design process of traditional power transformers. Some of the challenges and shortcomings of conventional transformers can be partially overcome by using solid state transformers (SST). Thanks to the availability of advanced power semiconductor devices capable of handling medium voltage levels, there is a significant growth in the use of the SST technology in the smart-grid and traction application. This paper has analysed the possibility of SST implementation on ships.

The shipboard power distribution system has been developed in order to make it more efficient. AC zonal distribution system is one of the options in order to achieve the objection. This study aims to observe the shipboard application with AC zonal distribution system. The distribution system is modeled, simulated, analyzed, and compared with conventional system. Based on simulation, the AC zonal distribution system provide higher reliability, better power continuity, and more stable power generation. Therefore, development of the zonal distribution system continues to bring succeed in every mission. However, the system has several challenges for future work such as more complex transmission system, higher voltage drops, and the tendency to have instability power distribution when one generator fails.

With the extensive electrification introduced into the shipboard power systems, the navigation routine has become more important in an electric propulsion and solar power integrated ships since various sailing paths and speeds will lead to different operation performances. Unlike traditional navigation, which solves the shortest path problem, a data-driven optimization scheme is developed in this article for a photovoltaic (PV)-dependent navigation routing. In order to minimize the total cost and greenhouse gas emissions of an all-electric ship (AES), a new coordinated optimization framework is proposed to jointly optimize the energy storage system (ESS) sizing and voyage scheduling while considering solar power variations. Several cases are compared to verify the proposed method on a cargo ship, and numeral results reveal that the deep-learning-based forecasting method can better characterize the onboard solar power variations, and the proposed joint optimization framework can well accommodate the onboard PV generation.

Due to the increasing concerns about the environmental and economic issues of traditional ships, all-electric ships with energy storage and renewable energy integration have become more and more appealing for the forthcoming future. In this paper, an optimal energy storage system (ESS) capacity determination method for a marine ferry ship is proposed; this ship has diesel generators and PV panels. ESSs sizing optimization and power system scheduling optimization are simultaneously conducted and it is converted to a mixed-integer quadratic programming (MIQP) model with special modeling techniques. The case study shows that the proposed method is flexible and effective, and the relationships between the ESSs size and the discharge rate, life cycle times, or initial investment cost are investigated.

The following is a comprehensive analysis which details potential ways for the maritime industry to begin to phase out AC power generation and distribution on new vessels over a short period of time. Therefore, the vessels of the future should consider transitioning into DC power generation and distribution. During the transition from AC shipboard systems to DC shipboard systems, there will be a time during which the vessels will be run by shipboard power systems, which utilize a mixture of AC and DC power. These systems are known as integrated marine power systems (IMPS) or hybrid maritime microgrid architectures, since they represent a distribution system or a part thereof. This study presents a state of the art of maritime systems, emphasizing on the design aspects of hybrid maritime microgrids, summarizing the advantages, disadvantages, and the challenges that planners may face when it comes to the vessels of the future. This study also reviews remedies that have been recently proposed in the literature to overcome such challenges. In addition, this work reports on the problem of service restoration of shipboard power systems and introduces directions on how to enhance the survivability of maritime power systems using techniques based on distribution system reconfiguration.

Testability design of power distribution system considering noise immunity characteristics

The increasing use of power electronics in power systems causes a high injection of harmonic components which can in turn interfere with utility equipment and customer loads. Therefore, the correct estimation and measurement of harmonics have become an important issue. If the power frequency of the signal is steady and near the nominal value, the discrete Fourier transform (DFT) can be used and good estimation performance is achieved. However, there are considerable power frequency variations on isolated systems such as shipboard power systems, micro-grids and smart-grids. When these variations occur there may be significant errors in the estimates using the DFT. In order to deal with this problem, this work presents a novel technique based on demodulation of the power line signal and subsequent filtering for harmonics estimation. The main features of the proposed harmonic estimation technique are: precise and accurate estimation of harmonics of off-nominal frequencies and fast estimation of harmonics (about two cycles of the fundamental component). Simulation results show that the proposed technique performs well in comparison with the DFT and can be a good candidate to replace it in cases where the power frequency is subject to considerable variations.

The power supply efficiency in industrial parks directly impacts production stability and energy costs for enterprises. Traditional decentralized distribution often leads to redundant equipment configuration, increased transmission losses, and complex multi-site dispatch challenges, undermining overall operational efficiency. When facilities with differing characteristics coexist within the same park, pronounced load fluctuation variations emerge, heightening demands for power supply reliability and increasing energy management complexity. This necessitates establishing a unified power supply and distribution optimization plan. Therefore, this paper explores the design of a joint power supply and distribution system for multi-site facilities, aiming to enhance the economic viability and practicality of industrial cluster power supply and distribution systems.