MARINE ELECTRO-TECHNIQUE 1

Types of Underground Cables (continue)- 8 •Paper Insulation –3 core belted 11kV PILC cable –Single core screened 11 kV PILC cable •Polymer Insulation –3 core XLPE 11 kV cable –Single core XLPE 11 kV cable

Types of Underground Cables (continue)- 9 Example of Single core screened 11 kV PILC cable • A = Conductor (Aluminum) • B = Strand Screen (carbon black paper ) • C = Insulation (Paper) • D = Insulation Screen (carbon black paper) • E = Sheath (copper lead) • F = Jacket

Types of Underground Cables (continue)- 10 • A = Conductor Example of Single core XLPE 11 (Aluminum) kV cable • B = Strand Screen (extruded semiconducting) • C = Insulation (XLPE) • D = Insulation Screen (extruded semiconducting) • E = Shield (copper tape) • F = Jacket

Types of Underground Cables (continue)- 11 – Excellent Electrical & Physical Properties – Capable Of Carrying Large Current At High Temperature • Normal ~ 90oc • Emergency ~ 130oc • Short Circuit Conditions ~250oc – Easy To Install – XLPE Easier To Joint – No Need For Metallic Sheath

6.6 (CABLE FAULT) INTRODUCTION

Cable Fault Introduction (continue)- ������ Cable faults are undesirable causes because:- 1. Power supply is interrupted 2. Locating fault in a long underground cable is difficult and time consuming 3. Repairing faulty cable is difficult and time consuming,

CAUSES OF UNDERGROUND CABLE FAILURE Major factors that cause failure of a cable are:- • Damaged accidentally by external mechanical means • Damage caused as a results of mishandling the cable during layout. • Poor workmanship in cable jointing. • Natural causes due to aging of cable. • Damaged caused by movement of soil and erosion

MECHANICAL

MISHANDLING Mishandling of cable may be occurred during installation Some of the examples are: 1. Excessive pull 2. Sharp bend. 3. Accident crush.

Poor workmanship During Cable Jointing The cable are jointed together with poor workmanship can lead to cable fault after a period of time.

NATURAL CAUSES DUE TO AGING OF CABLE

CONTINUE-

CONTINUE-

TYPES OF CABLE FAULT GENERAL: • Series (open circuit) Fault - Failure of continuity (conductor (s) or cable) • Shunt (short circuit) fault - failure of insulation

TYPES OF FAULT (CONTINUE)-

TYPES OF FAULT (CONTINUE)-

LMD13003 MARINE ELECTRO-TECHNIQUE 1 Chapter 4 Power Supply & Battery

 Every ship is to be provided with a main source of electrical power with sufficient capacity to meet the requirements.  This main source of power shall consist at least two mutually independent generating sets.  The capacity of generating sets must be such that, if one generating set should fails or shut down, the remaining generating capacity is sufficient to supply all those items of equipment needed when navigating at sea to ensure: ◦ normal operation conditions of propulsion and safety of the ship. ◦ minimum of comfortable conditions of habitability. ◦ preservation of cargo. 2

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 Dead ship condition means a condition under which: i. The main propulsion plant, boiler and auxiliary machinery are not due to the loss of the main source of electrical power ii. In restoring propulsion, the stored energy for starting the propulsion plant, the main source of electrical power and other essential auxiliary mcmhinery is assumed to not available 4

 Blackout situation means the loss of the main source of electrical power resulting in the man and auxiliary machinery to be out of operation 5

i. Power source ii. Emergency generator sets iii. Emergency services iv. Periodic testing v. Transitional source of power 6

Many vessel regain control of their electrical systems through the use of an: ➢ emergency generator ➢ emergency switch board ➢ Emergency source of electrical power may also be accumulator battery. 7

The emergency source of electrical power is a generator it must be :  Driven by a prime mover with an independent supply.  Started automatically upon failure of the main source of electrical powe supply.  Automatic connected to the emergency switchboard in not more than 45 second. 8

 The generator is provide with its own starting system.  When power is lost, the emergency must be able to automatically start and provide power to the emergency switchboard.  A manual start up may be initiated by push button in the main control roomn and in the emergency generator room. 9

 Ligthing  Steering gear  Propulsion equipment  The radio equipment  The navigation aids: • magnetic compas • Gyro compas • Radar • Echo sounder • Rudder angle indication • propeller 10

 The fire detection and alarm system  Emergency signal  Fire pump 11

 The emergency generator may be used exceptionally for short period services.  The routine testing for services must be check properly such as dead ship start up automatically 12

 Where the emergency generator is not provided with automatic starting, a transitional source of emergency electrical power is to be fitted.  The transitional source of emergency electrical power where consists of an accumulator battery which is supposed to operate without recharging. 13

All engineers are to follow the bellow mentioned duties in case of a blackout: 1. Chief engineers resposibility: ▪ overall in charge ▪ To change over main engine control to ECR ▪ To restart the main engine when power is restored and stabil. 14

2. Second engineers responsibility:  to find the cause of blackout  To start the standby auxiliary engine on manual mode if required 3. Third engineers responsibility:  to monitor the emergency generator engine and panel. To adjust the emergency generator voltage , load and frequency To start the emergency air compressor 15

3. Fourth engineer reponsibility:  To change over fresh water generator valve  To shut purifier valve  To assist the second engineer 16

 Shore supply is generally required to the ships generator and their prime mover can be shut down for major overhaul during a dry docking period.  Therefore, ship’s generators must disconnected before shore supply resume connection – interlocked provided  Shore supply may also connected directly to emergency board - ‘back feeds’ to main switchboard 17

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Battery 19

Duracell batteries 9v battery 6v dry cell Two cells A real battery Another battery More precisely

e− consumer salt bridge oxidation ZnSO4 CuSO4 reduction at zinc Half Cell I Half Cell II at copper anode cathode

 Zinc is (much) more easily oxidized than Copper Zn ⎯⎯→ Zn2+ + 2e− (I.) Cu2+ + 2e− ⎯⎯→Cu (II.)  Maintain equilibrium electron densities  Add copper ions in solution to Half Cell II  Salt bridge only carries negative ions ◦ This is the limiting factor for current flow ◦ Pick a low-resistance bridge

Most wants to But, there’s a reduce (gain reason it’s a electrons) sodium drop  Gold  Iron  Mercury  Zinc  Silver  Aluminum  Copper  Magnesium  Lead  Sodium  Nickel  Potassium  Cadmium  Lithium Most wants to oxidize (lose electrons)

 Size ◦ Physical: button, AAA, AA, C, D, ... ◦ Energy density (watts per kg or cm3)  Longevity ◦ Capacity (Ah, for drain of C/10 at 20°C) ◦ Number of recharge cycles  Discharge characteristics (voltage drop)

 Cost  Behavioral factors ◦ Temperature range (storage, operation) ◦ Self discharge ◦ Memory effect  Environmental factors ◦ Leakage, gassing, toxicity ◦ Shock resistance

 Zinc carbon (flashlights, toys)  Heavy duty zinc chloride (radios, recorders)  Alkaline (all of the above)  Lithium (photoflash)  Silver, mercury oxide (hearing aid, watches)  Zinc air

 Chemistry Zinc (-), manganese dioxide (+) Zinc, ammonium chloride aqueous electrolyte  Features +Inexpensive, widely available ◦ Inefficient at high current drain ◦ Poor discharge curve (sloping) ◦ Poor performance at low temperatures

 Chemistry Zinc (-), manganese dioxide (+) Zinc chloride aqueous electrolyte  Features (compared to zinc carbon) +Better resistance to leakage +Better at high current drain +Better performance at low temperature

 Chemistry Zinc (-), manganese dioxide (+) Potassium hydroxide aqueous electrolyte  Features +50-100% more energy than carbon zinc +Low self-discharge (10 year shelf life) ±Good for low current (< 400mA), long-life use ◦ Poor discharge curve



 Chemistry Lithium (-), manganese dioxide (+) Alkali metal salt in organic solvent electrolyte  Features +High energy density +Long shelf life (20 years at 70°C) +Capable of high rate discharge ◦ Expensive

 Nickel cadmium  Nickel metal hydride  Alkaline  Lithium ion  Lithium ion polymer  Lead acid

 Chemistry Cadmium (-), nickel hydroxide (+) Potassium hydroxide aqueous electrolyte  Features +Rugged, long life, economical +Good high discharge rate (for power tools) ◦ Relatively low energy density ◦ Toxic

 Chemistry LaNi5, TiMn2, ZrMn2 (-), nickel hydroxide (+) Potassium hydroxide aqueous electrolyte  Features +Higher energy density (40%) than NiCd +Nontoxic ◦ Reduced life, discharge rate (0.2-0.5C) ◦ More expensive (20%) than NiCd