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IEEE Press
445 Hoes Lane
Piscataway, NJ 08854



IEEE Press Editorial Board
Ekram Hossain, Editor in Chief
Giancarlo Fortino Andreas Molisch Linda Shafer
David Alan Grier Saeid Nahavandi Mohammad Shahidehpour
Donald Heirman Ray Perez Sarah Spurgeon
Xiaoou Li Jeffrey Reed Ahmet Murat Tekalp

Shipboard Power Systems
Design and Verification
Fundamentals



Mohammed M. Islam














Published by
Standards Information Network


Wiley Logo


Wiley Logo






Dedicated to my wife, Raihana Islam

Preface

Shipboard electrical system design and development fundamentals have changed from traditional low-voltage to medium-voltage generation and distribution due to higher power requirements. Power electronics application is playing a major role, including adjustable speed propulsion drives and variable frequency drive for ship service auxiliary applications. The guidelines for shipboard use of medium-voltage adjustable speed drive (ASD) require further amplification. This book provides step-by-step details of widely accepted design applications for shipboard electrical engineering design fundamentals. These fundamentals are somewhat different for different class such as commercial ships, military ships, and offshore floating vessels. The design fundamentals of electrical power generation prime movers, the requirements of the distribution system, and the transition to various services, must meet safety requirements. These design and development fundamentals are presented to use as a guide for any new design. Additionally, design and verification of the design with multiple options is also a requirement, as modeling and simulation with hardware in the loop has become a norm at the fundamental design level. An attempt has been made to initiate design verification at a very early stage of design and carry it through to the detail design, procurement, installation, and commissioning stages.

The adjustable speed drive also contributes to major system-level electrical noise such as harmonics and transient instability. Harmonic requirements and guidelines such as IEEE 519 and IEEE 1584 play a vital role for industrial application. However, for the ungrounded shipboard power system one must be careful as to the use of IEEE 519 and IEEE 1584. The concept of complying with requirements for harmonic mitigation must be supported by the fact that the equipment will perform in a safe manner so that operators are safe, electrical power system coordination is properly engineered, and the transient aspect of the entire shipboard power system is managed very much within the required design boundary. Lack of verification of design fundamentals often leads to unsafe electrical systems. If the design is not properly integrated, at some point in the design and development phase additional corrective measures may be necessary to optimize it. However, the design solution may not be implemented due to practical constraints. At the preliminary or detail design phase, it is easy to demonstrate that the system will meet the requirement to enhance capability by using a system-level simulation such as a physics-based solution. A physics-based simulation such as Smart Ship System Design (S3D) is introduced to initiate an iterative process to prove the design concept with alternative choices and then select the one best suited for specific application.

The design and development of the shipboard power system is presented here as it began in the early 1970s; prior to that, the baseline shipboard power system design had been the same for many years. Electrical design and development changes accelerated when shipboard auxiliary systems of mechanical and hydraulic systems were being replaced with electrical systems. The author has gone through the real design challenge of developing an integrated electrical power system while designing a USCG Healy Icebreaker electrical propulsion medium-voltage distribution system. This involved the development of a medium-voltage system for shipboard adjustable speed propulsion for the Healy Icebreaker and medium-voltage generation and distribution for tankers. The design and development process was a challenge, such as, for example, to apply a 6-pulse versus a 12-pulse propulsion drive for the Healy Icebreaker and then quantify the total harmonic distortion (THD) of the electric propulsion system during the worst operational conditions.

The ship electrical system grounding requirement has become very challenging as the shipboard power system has taken a major shift from low-voltage ungrounded generation and distribution with a simple ground detection system to high-resistance grounding along with complex power generation and distribution requirements. This book addresses the medium-voltage distribution system with a resistance grounding system and then the impact of resistance grounding in view of ASD utilization-related grounding issues. The book provides multiple popular designs with resistance grounding, with variations to make designers aware of the implications of a concept which may or may not be considered an optimal design.

The shipboard electrical power system with high voltage and high power generation poses many challenging issues, such as complex, system-level protection coordination, sophisticated grounding requirements for ungrounded systems, special types of cable to deal with voltage surge and transients, harmonics, and special power filters for harmonic management.

At the system level of design and development, it has been recognized that a system with ASD may not maintain Class-I type power; the use of the Uninterruptable Power System (UPS) at higher power is being used. However, UPSs also bring solid state power electronic-related challenges.

The shipboard low voltage ungrounded power system ground detection and monitoring system is usually a simple detection system with lights for monitoring voltage variations. The IEC has developed completely different recommendations from the ground detection light with the understanding that the legacy system does not contribute to the management of real grounding danger, as the system leads to arcing and then bolted fault. The IEC requirement is to monitor and intervene as the electrical system starts making the transition from symmetric to asymmetric behavior. In case any ground is detected in the ungrounded electric system on ships, corrective action must be fast enough to protect the system from an arcing fault, explosion, and related equipment failures.

When a technological breakthrough challenges the real-life engineering application, sometimes failure may be encountered, which is the process of design and development. There must be a cause and effect analysis of the failure to get to the root cause and then take immediate corrective action. The corrective action process can be excruciating; however, finding a comprehensive and permanent solution is a must. Sometimes, multiple solutions may be adapted with multiple layers of protection to have a permanent solution. Whatever the design and development process is, the designer must have a thorough understanding of the solution being adopted.

This evolving engineering process of accepting technology's spiraling development is a normal developmental phenomenon. When a technology is accepted for development, it is considered to be working at present; however, it cannot be guaranteed for the future. As the technology is used, it becomes a candidate for standardization. Such is the case for IEEE 45-related standards for shipboard electrical power systems.

The selection of cable for an adjustable speed drive application is also a fundamental challenge of the IPS ship design application. This book provides in-depth analysis of cable-application challenges with recommended solutions.

As offshore-industry-related vessels embark on ASD-, VFD-, and AFE-type electrical installations, the challenging issues for the ships are also applicable.

The “all electric ship” concept of power generation and distribution with propulsion ASD and auxiliary system with VFD provide many operational advantages such as propeller torque delivery at any desired RPM and auxiliary system control at any speed. However, those controllers contribute other undesireable issues which the designer must understand and take appropriate measure. Some of these issues are:

The terminologies used for the design and development of VFD-related equipment mainly follow IEC standards. IEC terminologies and symbols are different from ANSI terminology and symbols. It is very important to understand the difference between IEC and ANSI standard electrical devices. These differences are identified along with examples, for the benefit of design engineers.

Grounding terminologies are different between ANSI and IEC standards. The IEC standard has PE, SG, and many other symbols associated with grounding. Those symbols create major confusion for design engineers.

This book provides guidelines emphasizing the safety and security of electrical and electronic equipment installation, equipment selection, and system coordination. The responsibility for implementing these recommendations belongs to everyone dealing with shipboard electrical equipment and electrical systems, such as electrical engineers, electrical designers, electrical cable pullers, electrical equipment installers, shipboard equipment and system testers, and troubleshooters.

At any voltage level, electricity is deadly. Traditionally, shipboard electrical voltage ratings have been 12 V, 24 V, 110 V, and 460 V for grounded and ungrounded installations. Until recently, the 460 V level was high for shipboard installation. In recent years the voltage level has risen to 4100 V, 6600 V, 11,000 V, and 13,800 V. The power requirement has increased from a few megawatts to hundreds of megawatts. Power generation and distribution at different voltages and at hundreds of megawatts have become a big challenge. IEEE Std 45 recommendations are a supplement to American Bureau of Shipping (ABS) rules and US Coast Guard (USCG) regulations for commercial ships. In the endeavor to standardize international rules and regulations, and with the advent of information technology, we have access to an enormous amount of technical information related to shipbuilding innovations, rules, regulations, and standards. Information technology has helped tremendously to make necessary information available at the click of a mouse. The responsibility to gain knowledge of available shipbuilding rules, regulations, and recommendations around the globe and adapt the most appropriate ones must be carried out at a very fast pace. The adaptation of the very process of technical innovation is also a universal challenge of building a bridge from present to future shipbuilding in order to meet tomorrow's demand.

The concept of IEEE Std 45 arose with the same objective as that of the National Electric Code® (NEC®). Acceptable standards are needed because no two persons will view something in the same way, interpret it in the same way, and implement it in the same way. These standards are critical in applying technology, which is a time-domain domino scenario by the very nature of innovation. As we build for the future, we have to live with the present. We must write down the most probabilistic aspect of an idea and agree to follow it. The accepted norm of today may not be the norm of tomorrow; however, it is appropriate today because it works to an accepted level and meets safety requirements.

Industry experts have contributed many years of experience in the shipboard electrical engineering field. Their task, however, has been presented with a significant challenge due to the global cooperation initiative, namely harmonization and globalization. IEEE Std 45 is in compliance with the NEC, the National Electrical Manufacturers’ Association (NEMA), the Underwriters Laboratories (UL), the American Association of Testing and Material (ASTM), the American Bureau of Shipping (ABS) Rules, the Code of Federal Register (CFR) of the United States Department of Transportation, and various military specifications. The very process of equipment specification, manufacturing, installation, and testing has attained solid ground by the repeated revision of existing standards and the addition of new ones. IEC standards are also applicable for shipboard installation. The United States is a signatory to the IEC standards through the United States National Committee of the International Electrotechnical Commission, administered by the American National Standards Institute (ANSI). IEC standards differ from US standards in numerous ways, such as voltage level, unit of measurement, equipment rating, ambient rating, enclosure type, and equipment location classification. One must understand the differences to ensure applicability and interchangeability and combine the use of US standard equipment with IEC standard equipment. Most US standards committees have agreed to adopt IEC standards to supplement and change US standards. The IEEE Std 45 committee has also agreed to adopt IEC standards by directly replacing or modifying existing standards. These changes must be clearly understood in order to ensure that the safety and security of life and equipment are not compromised.

Smart Ship System Design (S3D) has been introduced as a new design environment with physics-based simulation and virtual prototyping of overall ship design, which is then compared with real system interaction for electrical power generation, distribution, protection, and automation.

There are many electrical one-line diagrams presented for design engineers who will be able to analyze different aspects of shipboard electrical distribution systems and then select the most appropriate one for application. If any one of the electrical one-line diagrams falls beyond the requirements of a regulatory body, the required correction must be made to ensure compliance.

This handbook is based on author's many years of ship building design experience and many years of experience in developing electrical standard for shipbuilding. The author wishes to thank all the individuals who have encouraged and contributed to the preparation of this book. The author also wishes to thank all IEEE 45 DOT standard working-group members for sharing technical know-how and expertise over the years, and technical experts in the marine field whose works may have been quoted in this handbook.

MOHAMMED (MONI) ISLAM