zxc ® 14-Jan-2016 17:22

Marine Electrical Knowledge


Year: 2014
Language: english
Author: Willem Maes
Genre: Technical book
Publisher: Antwerp Maritime Academy
Format: PDF
Quality: eBook
Pages count: 63
Description: The function of a ship's electrical distribution system is to safely convey elec- trical power to every item of equipment connected to it. The most obvious element in the system is the main switchboard. The main board supplies bulk power to motor starter groups (often part of the main board), section boards and distribution boards. Transformers interconnect the HV and LV distribution sections of the system.
Circuit breakers and fuses strategically placed troughout the system automatically disconnects a faulty circuit within the network. The main switchboard is placed in the engine controlroom and from there engineroom staf monitor and control the generation and distri- bution of electrical power. It is very important that every engineer has a profound knowledge of the electrical distribution of the ship's power. The only way to aquire this knowledge is to study the ship's power diagrams.
Almost all oceangoing ships have an A.C. distribution system in preference to a direct current D.C. system. Usally a ship's electrical distribution scheme follows shore pratice. This allows normal industrial equipment to be used after being adapted and certified where and if necessary, so it can withstand the conditions on board of a ship (e.g. vibration, freezing and tropical tem- peratures, humidity, the salty atmosphere, etc. encountered in various parts of the ship). Most ships have a 3-phase A.C., 3-wire, 440V insulated-neutral system. This means that the neutral point of star connected-generators is not earthed to the ship's hull.
Ship's with very large electrical loads have generators operating at high voltages (HV) of 3.3KV, 6.6KV, and even 11KV. By using these high voltages we can reduce the size of cables and equipment. High voltage systems are becoming more common as ship size and complexity increase.
The frequency of an A.C. power system can be 50 Hz or 60Hz. The most common power frequency adopted for use on board ships is 60Hz. This higher frequency means that generators and motors run at higher speeds with a consequent reduction in size for a given power rating. Lighting and low power single-phase supplies usually operate at 220 V. This voltage is derived from a step down transformer connected to the 440 V system.
Additional info: Video Practical Marine Electrical Knowledge - Willem Maes https://seatracker.ru/viewtopic.php?t=3768

Contents

Contents
1 Electrical Distribution. 7
1.1 Power Distribution . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2 Grounding systems in shipboard electrical networks. 8
1.3 Electrical faults . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.1 Earth fault . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.2 Open circuit fault . . . . . . . . . . . . . . . . . . . . . 10
1.3.3 Significance of Earth Faults . . . . . . . . . . . 10
1.3.4 An Electric Power System's Reliability . . . . 11
1.3.5 Sectioning of the distribution system and providing
multiple power sources . . . . . . . . . . . . . . . . . . 11
1.3.6 Emergency power systems . . . . . . . . . . . . . . . . 11
1.3.7 Sectioning of circuits . . . . . . . . . . . . . . . . . . . 11
1.3.8 Selectivity . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.3.9 Overcurrent Selectivity . . . . . . . . . . . . . . . . . . 12
1.3.10 Time lag selectivity . . . . . . . . . . . . . . . . . . . . 12
2 A Ship's Electrical System. 13
2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2 Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3 Electric motors . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4 Starting devices . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4.1 Direct-on-line starters . . . . . . . . . . . . . . . . . . 14
2.4.2 Reduced voltage starting . . . . . . . . . . . . . . . . . 14
2.4.3 Primary resistance starting . . . . . . . . . . . . . . . . 15
2.4.4 Autotransformer starters . . . . . . . . . . . . . . . . . 15
2.4.5 Star-delta starters . . . . . . . . . . . . . . . . . . . . . 16
2.4.6 High voltage choke starter . . . . . . . . . . . . . . . . 16
2.4.7 Electronic softstarters . . . . . . . . . . . . . . . . . . 16
1
3 Auxilliary Electrical services. 18
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.2 Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.2.1 Incandescent lighting. . . . . . . . . . . . . . . . . . . . 18
3.2.2 Discharge Lamps . . . . . . . . . . . . . . . . . . . . . 19
3.2.3 Navigation and Signal Lights . . . . . . . . . . . . . . 27
3.2.4 Emergency Lighting . . . . . . . . . . . . . . . . . . . 29
3.3 Cathodic Protection For Ships. . . . . . . . . . . . . . . . . . 31
3.3.1 History. . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.3.2 A litle electrochemistry . . . . . . . . . . . . . . . . . . 31
3.3.3 What is cathodic protection. . . . . . . . . . . . . . . . 32
3.3.4 Cathodic protection in human language . . . . . . . . . 33
4 High Voltage Safety. 39
4.1 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.2 Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.3 De nitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.3.1 Additional earth . . . . . . . . . . . . . . . . . . . . . 41
4.3.2 Approved . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.3.3 Authorised person (AP) . . . . . . . . . . . . . . . . . 41
4.3.4 Caution notice . . . . . . . . . . . . . . . . . . . . . . 41
4.3.5 Chief engineer . . . . . . . . . . . . . . . . . . . . . . . 41
4.3.6 Circuit main earth (CME) . . . . . . . . . . . . . . . . 42
4.3.7 Competent person . . . . . . . . . . . . . . . . . . . . 42
4.3.8 Danger notice . . . . . . . . . . . . . . . . . . . . . . . 42
4.3.9 Dead . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.3.10 Earthed . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.3.11 High voltage (HV) . . . . . . . . . . . . . . . . . . . . 42
4.3.12 High voltage apparatus . . . . . . . . . . . . . . . . . . 42
4.3.13 Isolated . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.3.14 Key safe . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.3.15 Limitation of acces (LoA) . . . . . . . . . . . . . . . . 43
4.3.16 Live . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.3.17 Permit to work (PTW) . . . . . . . . . . . . . . . . . . 43
4.3.18 Safety lock . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.3.19 Sanction for test (SFT) . . . . . . . . . . . . . . . . . . 43
4.3.20 Designated person ashore (DPA) . . . . . . . . . . . . 43
4.4 What is classed high voltage onboard a vessel . . . . . . . . . 44
4.5 HV Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . 44
4.5.1 HV Insulation Requirements . . . . . . . . . . . . . . . 44
4.6 Major features of a HV system compared to a LV system . . . 45
2
4.7 Dangers when working on HV equipment . . . . . . . . . . . . 45
4.7.1 Electric shock . . . . . . . . . . . . . . . . . . . . . . . 45
4.7.2 Arc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.7.3 Arc Blast . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.8 Safe Working Procedures . . . . . . . . . . . . . . . . . . . . . 47
4.8.1 Seven steps that save lives . . . . . . . . . . . . . . . . 47
4.8.2 Aim and Scope . . . . . . . . . . . . . . . . . . . . . . 49
4.8.3 RISK ASSESMENT AND CONTROL . . . . . . . . . 49
4.8.4 Use of Permits . . . . . . . . . . . . . . . . . . . . . . 49
4.8.5 Lock out - Tag out . . . . . . . . . . . . . . . . . . . . 50
4.9 Electrical Permit Work System . . . . . . . . . . . . . . . . . 54
4.10 Additional procedures to be implemented for HV systems . . . 55
4.10.1 Sanction-to-test system . . . . . . . . . . . . . . . . . . 55
4.10.2 Limitation of acces form . . . . . . . . . . . . . . . . . 55
4.10.3 Earthing Down . . . . . . . . . . . . . . . . . . . . . . 55
5 Classi cation and Certi cation 57
5.1 classi cation and certi cation for the equipment . . . . . . . . 58
5.2 Mechanical Standards . . . . . . . . . . . . . . . . . . . . . . 58
5.2.1 ISO . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.2.2 DIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.2.3 ANSI and ASME . . . . . . . . . . . . . . . . . . . . . 59
5.3 Electrical Standards . . . . . . . . . . . . . . . . . . . . . . . 59
5.3.1 IEC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.3.2 IEEE 45 . . . . . . . . . . . . . . . . . . . . . . . . . . 60
5.3.3 Other international electrical standards . . . . . . . . . 61
5.3.4 Marine Standards . . . . . . . . . . . . . . . . . . . . . 61
3
List of Figures
1.1 Insulated and earthed neutral systems. . . . . . . . . . . . . . 8
1.2 circuit faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3 circuit faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.1 asynchronous motor . . . . . . . . . . . . . . . . . . . . . . . . 14
2.2 autotransformer starter main circuit . . . . . . . . . . . . . . . 15
3.1 Incandescent lamp. . . . . . . . . . . . . . . . . . . . . . . . . 18
3.2 Tungsten-halogen lamp. . . . . . . . . . . . . . . . . . . . . . 19
3.3 Low pressure mercury
uorescent lamps. . . . . . . . . . . . . 20
3.4 A
uorescent lamps lament. . . . . . . . . . . . . . . . . . . 20
3.5 Ballast. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.6 The preheat starter. . . . . . . . . . . . . . . . . . . . . . . . 21
3.7 The preheat starter circuit. . . . . . . . . . . . . . . . . . . . . 22
3.8 Germicidal lamp. . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.9 Mercury-vapor lamp. . . . . . . . . . . . . . . . . . . . . . . . 24
3.10 HP mercury-vapor lamp and circuit. . . . . . . . . . . . . . . 24
3.11 SOX lamp and circuit. . . . . . . . . . . . . . . . . . . . . . . 26
3.12 SON lamp and circuit. . . . . . . . . . . . . . . . . . . . . . . 26
3.13 Ship's navigation lights requirements. . . . . . . . . . . . . . . 27
3.14 Navigation Light Panel. . . . . . . . . . . . . . . . . . . . . . 28
3.15 Ship's navigation lights arrangement. . . . . . . . . . . . . . . 28
3.16 Navigation lights circuit. . . . . . . . . . . . . . . . . . . . . . 28
3.17 Xmas tree. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.18 Signal lights switchboard. . . . . . . . . . . . . . . . . . . . . 29
3.19 anodic reaction and cathodic reaction. . . . . . . . . . . . . . 31
3.20 No protection at all. . . . . . . . . . . . . . . . . . . . . . . . 33
3.21 Propeller shafting may require bonding to the hull. . . . . . . 34
3.22 Sacri cial cathode system. . . . . . . . . . . . . . . . . . . . . 35
3.23 sacri cial anodes on a ship's hull. . . . . . . . . . . . . . . . . 35
3.24 Impressed current system. . . . . . . . . . . . . . . . . . . . . 36
3.25 Ships anodes and impressed current control system. . . . . . . 37
4
3.26 Impressed current system on a tanker. . . . . . . . . . . . . . 38
3.27 Impressed current anode. . . . . . . . . . . . . . . . . . . . . . 38
3.28 Sacri cial anodes in a ballast tank. . . . . . . . . . . . . . . . 38
Rating: 4.9 / 5 (Votes: 37)
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