1.0 INTRODUCTION
The shipboard electrical system design process consists of concept design, preliminary design, detail design, design development, design verification, installation, and commissioning. Shipboard power-system design and development is an engineering art that requires many years of engineering experience, specifically, designing electrical systems with experienced engineers. Shipboard electrical system design and development has become very challenging due to complex electrical power generation and distribution requirements including higher voltage, high power, and adjustable speed propulsion drives. The ship propulsion system has changed from direct mechanical drive to an electric motor with an adjustable speed drive. The across the line starters for auxiliary systems are being replaced with adjustable frequency/speed drive. Solid-state power electronics are being programmed to perform necessary ASD functions. However, solid-state devices and functionality also have some drawbacks, such as electrical noise. Most of the power electronic application-related hardware for shipboard application is migrated from well-established, shore-based industrial applications. There are subtle differences where industrial-based equipment is not suitable for shipboard applications. The shipboard power-system design process needs to be validated by methodical analysis with pros and cons. Sometimes the design process must go through a physics-based simulation process including hardware in the loop simulation to ensure that the design is optimized. The modeling and simulation of a shipboard electrical system provides many design options so that optimal design can be adapted for a custom shipboard design application. This book describes the following design and development process:
- Basic design process, verification, and validation
- Modeling and simulation-based design and verification
- Smart ship system design (S3D)
Shipboard electrical power generation and distribution requirements are guided by rules, regulations, standards, and established recommendations by authorities having jurisdiction in the design and development field. Power-system design engineers are to follow these guidelines to design required systems and get the design approved by the authority having approval jurisdiction. The shipboard low-voltage power system includes 1000 V, 690 V, 480 V, 230 V, and 120 V at 60 Hz and DC power at the voltage range from 12 V to 48 V, etc. The medium-voltage system includes all voltages from 1000 V to 35 kV AC as applicable for specific application. This book covers up to 15 kV maximum (11 kV or 13.8 kV nominal per MIL-STD-1399-300 and MIL-STD-680).
The shipboard power system consists of ship service power, emergency power, and propulsion power.
Shipboard power demand has evolved from a few megawatts to hundreds of megawatts. The voltage level has also been upgraded to 690 V, 2400 V, 4160 V, 6600 V, and beyond. Variable frequency drive or adjustable speed drive technology has become a dominant feature to mitigate propulsion-related higher voltage and high-power demand. The transition of proven VFD or ASD applications from industrial application to ship application has created many challenges.
The transition from low-voltage to medium-voltage generation and distribution may not have fathomed the requirements of grounded and ungrounded systems. The current practice of designing shipboard power generation and distribution systems may reflect a combination of both industrial and maritime applications.
Design engineers must understand the difference between industrial and ship applications of high voltage and high power. Design engineers must address these problems as uniform across all applications including shipbuilding; however, they should not arbitrarily consider the same solutions, as shipboard power generation and distribution fundamentals are different. For example, the harmonic noise problem can be addressed in general for all applications, but harmonic problem solution criteria for ships are different from those of other applications.
This handbook provides detail design and development of shipboard power generation and distribution based on low-voltage power generation and distribution, which has been well defined, as well as the medium-voltage system.
Model-based design has been presented to establish design variations and then the selection process starting from the concept design:
- Optimize the performance of the shipboard power system
- Optimize the functionality of the shipboard electrical network
- Define the requirements of electrical power equipment
- Define and coordinate the protective devices
- Reduce power losses
- Quantify harmonics contents and then systematically apply a harmonic management program to achieve an acceptable level
- Arc flas...
