SECTION1: SAUDI ARAMCO MARINE DEPARTMENT

The Marine Department operations are extensive and extend to various company organizations.

The Department is responsible for:

The provision of marine vessels and shore operations, technical, and engineering

services in support of Company operating areas in the Arabian Gulf and Red Sea.

The operation of the Company shore support and maintenance facilities at West Pier,

Tanajib, Abu Ali, Jeddah, and Rabigh.

The maintenance of navigational aids throughout Saudi Aramco offshore concession

areas.

The provision of engineering and technical expertise regarding marine operations, safe

navigation, seamanship, and underwater inspections and repairs.

I. ELECTRICAL REPAIR UNIT (ERU)

ERU is considered the most important unit in Saudi Aramco Marine Maintenance Department. It

is dividing into three parts Electrical Section, Communication Section and digital Section.

This is a work in performing and directing the maintenance and repair t marine electrical systems

on Marine Department Employee is responsible for the maintenance and repair o electrical and

electromechanical systems of marine fleets. Work involves participating in the supervising the

installation, maintenance and repair of AC generator, switchboards, and distribution panels.

Lighting and alarm circuits. Maintenance and repairs are performed without technical supervision

however, complex electrical repair prob1em may be performed under the general supervision of a

maintenance supervision or and are reviewed and evaluated through the continued and reliable

operation of all electrical systems and their ability to meet Aramco requirements. Next, there are

examples of duties performed like Trouble shoots, electrical equipment, and circuits using

appropriate test equipment to detect and affect required maintenance, repairs or replacement

requirements. Performs maintenance and repair of generators. Switchboards, controllers, circuit

breakers, electrical motors, distribution panels, alarm and lighting circuits. Conducts insulation

resistance measurements of electrical cables to determine condition and effects repairs or

replacements as required.

II. ASSIGNMENT OBJECTIVE During the six months assignment with the marine electrical repair unit (ERU) the employee

should be able to acquire “hands-on” experience in the following field,

Familiarization of functions, general overview and responsibilities of ERU.

To be familiar with various system condition and requirement needed to operate the

system in safe and reliable manner.

Develop a basic understanding of a system problem and typical operating problems that

occur and steps needed to resolve them.

To be familiar with work procedure in ERU and its interaction with other organizations.

To become familiar with different types of generators, motors, transformers, breakers,

electronics systems and their accessory.

To be familiar with the operation of the test equipment devices.

Work Activates Orientation to Marine maintenance and shore operation division and explain the

organization of this unit and safety procedures associated, 1 week.

Will be assigned for three months with digital shop where he will gain field experience

and learn about

• Shop repairs.

• Operation of test equipment.

• Troubleshooting/ repairs most of the electronic systems in marine

department like Gyrocompass, echo sounder, alarm system (Racal Dacca),

phone interface network , video monitor, auto pilot and voltage regulator.

Will be assigned for three months with electrical shop and will be exposed to shop

activities on the following:

• Generators and Motors.

• Pumps.

• Transformers.

• Circuit breakers.

• All kinds of marine lights & emergency light.

• Power management system.

• Steering system.

• Batteries and Cables.

• Relays.

• Switch board.

III. MARINE VESSELS

Diving work boat, Maintenance work boat, Hydrographic survey boat, Jack-up barge, Pilot boat,

Pollution boat and Docking tug.

A) ARRABIYAH 1 (Jack-up barge)

These vessels are utilized for Maintenance, Producing and Well Service operations. Some are

capable of mobilization for repairs and maintenance on pipelines, tanker-loading facilities, power

cables, and can be used for replacing navigation piles. They are the largest vessels in the Saudi

Aramco fleet and their use greatly reduces weather downtime in offshore operations, as once the

vessel is in jacked up mode a stable platform is provided for the work. Each barge is equipped

with two or more cranes, and has a large open deck area to facilitate stowage of any specialist

user department equipment. There are 8 self propelled Jack-ups in the Marine Fleet, known as

Arabiyah’s 1 – 7 and the ARB-2. Four of the barges were built in Brazil and are powered by 4

azimuth thrusters. The remaining four Otis type jack-ups were built in the USA and Singapore,

and are powered by four clutched engines driving four propellers. Accommodation, dining and

laundry facilities are provided on each barge for the crew and user department personnel.

B) KARAN-8 (Hydrographic survey boat)

The Hydrographic Survey Boat is the Karan 8. This state of the art vessel is designed for all offshore survey

work. This highly maneuverable Dynamic Positioning vessel is assigned to the Hydrographic Survey Unit

and provides accommodation for up 10 Surveyors at any given time. The Karan 8 is also equipped with

small boats for inshore survey work.

IV. WORK ORDER During the two months we had two vessels under dry decking ARABIYAH 1 and KARAN 8. We

were working in these vessels by following the work order which mentioned below.

A) ARRABIYAH 1: it was scheduled to dry-docking refit for 4 months. And one the orders were

Alternators Inspection and repairs and the order is expressed in the following steps.

1) Alternators were disconnected from their associated engines to electrical shop for

complete strip down and overhaul of all components.

2) Disassembling each alternator and inspecting all internal parts. Inspect rotors, stators,

bearings bushings, and bushing housings for any signs of wear, damage, or overheating.

Repairing any defective parts found and renewing any parts beyond repair.

3) Inspecting each of the alternator’s Automatic Voltage Regulator, exciters circuits and

heaters for any sign of defective components.

4) Cleaning rotors and stators from any dust using an approved electrical solvent. Back

drying the rotors and stators and measuring insulation readings.

5) Reassembling each alternator and re-installing on original places.

B) KARAN 8: it was scheduled to dry-docking refit for 2 months. And one the orders was

Alternators Inspection and repairs. (See above same as ARRABIYAH 1). Second one was about

removing, disassembling, cleaning and inspecting Clean Power Motor Generator Set. Finally, it

was about Load Test and Sea Trial. The order is expressed in the following steps:

1) After completing of repairs to alternators and generator engines, performing a full load

test (using Ship’s invertor system) for each generator engine separately, for a period of at

least (4) hours.

2) After successful testing of each generator set, testing and proving all generator sets are

capable of parallel operation and proper load sharing capabilities.

3) Correcting all faults and making adjustments as required achieving proper operation of

generator sets.

4) Testing operates and proves all emergency trips are in satisfactory operation.

SECTION2: SR4 CATERPILLER T ELECTRICAL GENERATOR

I. INTRTODUCTION The SR4 Generator has no brushes and no commentator. This gives better performance and

longer service life. It uses a solid-state, automatic voltage regulator. This regulator has only one

moving part in the voltage build-up system. This part is completely sealed relay that is activated

only when the generator is started or stopped. KARAN 8 generators have the following

specifications. 1) 3 X CATERPILLER TYPE SR4 809, Single bearing, Self excited

volts/Hz voltage regulation, brushless, Class F insulation and the

output is 1365 kVA, 3x460 v, 60Hz, 3-phase.

2) 1 X CATERPILLER TYPE SR4 686, Single bearing, Self excited

volts/Hz voltage regulation, brushless, Class F insulation and the

output is 700 kVA, 3x460 v, 60Hz, 3-phase…

II. ALTERNATOR EXCITATION

1. Alternator excitation to be a static system (brushless). The excitation power to be taken from

the output terminals of the main alternator and controlled by a volt\pr.Hz voltage regulator.

2. The rectifiers and other solid state equipment employ to be capable of continuously carrying

the maximum excitation current of the alternator and are to be able to withstand any voltage

surges arising from all operating conditions of steady and transient loads including a short circuit

at the main machine terminals.

3. Means to be provided to divide the reactive power properly between generators when running

in parallel, by cross current compensation.

4. Failure of excitation system or voltage regulator should not cause damage to the installation.

5. Under steady short circuit condition, the current to be maintained at not less than 3 times the

rated current at least for 2 seconds.

III. VOLTAGE REGULTION 1. An approved make of static automatic voltage regulator designed to control the output voltage

from the alternator within ± 1% of the systems voltage is to be supplied with each generator set.

2. The AVR’s to regulate without adjustment when the alternators run with the P.F. as anticipated

nearing unity, at any and all tools.

3. The AVR’s to be fitted with voltage trimmers, for voltage adjustment of ±8% of the rated

voltage.

4. When stating the largest motor under normal sea load, the voltage dip is not to exceed limits

set by Classification Society and IEEE. If practical with a voltage recovery to within ±2.5% of the

rated voltage in less than 0.6 secs. And to ± 1% within 1 sec, dependent on sub transient

reactance of alternators selected to meet power factor and fault level limitations.

IV. THE CONNECTION OF GENERATOR IN KARAN 8 This figure below demonstrates the diagram connection of the 4 generators over the KARAN 8 vessel.

Also, this graph illustrates the components of SR4 generator.

V. GENERTOR COMPONENTS This generator contains stationary components and rotating components. In the first figure shows

the whole generator set but in the second one it shows the alternator part only.

A. Stationary Components I. Regulator.

2. Stator. 3. Field Coil (LI).

4. Exciter field (L2).

5. Voltage Regulation: It consists of 3 main potentiometers which they mentioned below.

a) Voltage level control located in the front of the regulator panel and used to adjust DC reference

level voltage.

b) Voltage Droop (R1) and gain (R3): The droop potentiometer (R1) is used in paralleling

operations with other generator. The voltage gain potentiometer is an adjustment to compensate

for voltage droop caused by generator load or governor speed droop.

c) Current Transformer (T4) takes the output off lead for dual voltage generates or for single

generators

B. Rotating Components I. Main field (L4).

2. Exciter armature (L3).

3. Permanent magnet (PMG).

4. Bridge rectifier (2).

VI. ASSEMBLEY AND DISASSEBLY OF GERERTOR First, we assemble the generator then we checked the parts and fixing the defects then

disassembly the parts by following those steps.

1) Rotor Assembly 2) Generator Bearings

3) Main Exciter Field 4) Bridge Rectifier and Exciter Armature

5) Regulator Assembly

VII. AFTER INSTLATION After finishing the maintenance order for the generators we installed the generators again in their

places and wiring them. Then, we made load test for the generators which are providing the

output they should, and at the proper voltage and frequency. After that, we made some voltage

and frequency adjustments by using VR3 Regulator Voltage Adjustment Controls. Finally we did

sea trial to check the operation of generators.

VIII. VOLTAGE ADJUSTMENT This adjustment is divided in two parts: Single unit operation and Parallel Operation by using VR3

Regulator Voltage Adjustment Controls as shown in the figure below. This VR3 has three main

potentiometers which are: Voltage Droop, Voltage level and Voltage Gain. Both of the operations

discussed briefly below.

A) Single Unit Operation To Adjust the Voltage Regulator we followed those steps:

1. We loosened the locknuts on the voltage droop, voltage level, and voltage gain controls. Then,

we turned voltage droop and voltage gain controls counterclockwise to zero droop and tightened

the locknut. Next, we turn the voltage gain control to about 1/4 of full range of clockwise travel.

2. We started the engine and allow it to warm. After that, Increasing engine speed to full

governed speed (high idle).

3. We observed the voltmeter reading and desired voltage is not indicated then we set no load

voltage with voltage level control potentiometer. After that we closed the load circuit breaker and

applying full load gradually. Then, we Adjusted governor control until we got 60 Hz frequency.

4. After that, we noticed that voltmeter reading increases with full load applied, we turned gain

control potentiometer slightly in counterclockwise direction.

5. Then we removed load and adjusting voltage level control potentiometer to obtain desired

voltage.

6. Next, applying the load, and repeated the last three steps until no load voltage equals full load

voltage.

B) Parallel Operation Preparing a generator for parallel requires special attention. Before parallel units for the first time, all

checked to be sure the following are met:

1. Same phase rotation

2. Same alternating current frequency

3. Same voltage adjustment

1) Phase Rotation The phase rotation must be the same. A set of three light bulbs can be used to determine

whether the phase rotation of the incoming unit and the phase rotation of the line are the same.

We followed these steps to determine proper phase rotation.

1. We connected the light bulbs between the generator leads and the corresponding line phase,

i.e., terminal 1 to line 1 across the open circuit breaker.

2. We starting the units to be paralleled and bring them up to speed. As they approach the same

speed the lights will start to blink operation attempting to units must be three conditions

3. Then we found that lights blink in sequence that means one of the units is connected backward. To

correct that, we removed generator leads 1 and 3 at the circuit breaker and exchanged them. This reverses

the direction of phase rotation. Line 2 should always be connected to line 2. But If lights blink both

engines is been met.

2) Frequency Adjustment The speed of units to be paralleled must be the same. Speed is proportional to the alternating

current frequency. Frequency adjustments can be done by following those steps:

1. Allowing each electric set to run under load (about

30 minutes).

2. Adjusting the governor control to give rated frequency at full load.

3. Removing the load and checking the high idle speed; it should be approximately 2 to 5% above

full load speed.

3) Voltage Adjustment The voltage level and voltage droop adjustments determine the amount of circulating currents

between generators. Carefully matched voltage regulator adjustments will reduce the circulating

currents. Loads of 0.8 power factors (primarily motors) require a generator voltage droop of about

5%. Voltage droop is expressed as the percentage of voltage change from no load to full load.

We followed those steps to adjust.

1. Adjusting voltage as described for Single Unit Operation.

2. With the engine running at high idle, turning the voltage droop clockwise about 1/2 of full range.

3. Readjusting the voltage level control until the voltage is about 5% above desired voltage.

4. Applying full load.

5. Readjusting the voltage droop control to obtain desired voltage with full load at 0.8 power

factor.

6. Repeating Steps 3, 4 and 5 for each generator to be paralleled until line voltage is equal to

desired level at full load and no load voltage is approximately 5% above rated voltage.

7. Paralleling generators and applying the driven load. Checking the output current of the

generator and the sum of the amps of the individual generator amperes exceeds the total amps

going to the load by 10% at full load that leads to adjust voltage droop controls to share current

proportionally between generators.

8. Making final adjustments after parallel generators have been running at full load for one hour or

more. Tightening the locknuts on all controls and installing the access cover.

SECTION3: LOAD SHARING I. INTRODUCTION The forward acting 2301A Control provides the electrical actuator with increased electrical signals

as more fuel is needed by the engine. This type of control will cause the governor to go to

minimum fuel position if the electrical signal is lost.

If the engine is provided with a reverse acting 2301A Control, a loss of electrical signal will cause

the electrical actuator to go to maximum fuel position. The reverse acting control must be used

with a reverse acting, ballhead backup actuator. With the loss of electrical signal to the control,

engine speed will increase until it is limited by the mechanical governor section of the actuator.

II. 2301A ELECTRIC GOVERNOR SYSTEM The 2301A Electric Governor Control System consists of the components that follow: 2301A

Control Box, Actuator, and Magnetic Pickup.

The 2301A Electric Governor System gives precision engine speed control. The 2301A Control

measures engine speed constantly and makes necessary corrections to the engine fuel setting

through an actuator connected to the fuel system.

The engine speed is felt by a magnetic pickup as shown in the figure above. This pickup makes

an AC voltage that is sent to the 2301A Control. The 231DM Control now sends a DC voltage

signal to the actuator.

The actuator changes the electrical input from the 2301A Control to a mechanical output that is

connected to the fuel system by linkage which is shown above. For example, if the engine speed

is more than the speed setting, the 2301A Control will decrease its output and the actuator will

now move the linkage to decrease the fuel to the engine.

III. EG-3P & EG-3PC ACTUATORS The EG-3P and EG-3PC Actuators are engine driven devices

that hydraulically change an electrical input to a mechanical

output (terminal shaft rotation) that controls the engine fuel rack

or carburetor.

SECTION4: LOAD TEST AND TRUBLESHOOTING

During the Load Test we faced this problem which mentioned below and we solved.

1) We did without load test for the operation Genertors.1, 2, 3 and 4 and it was good just we

needed some adjustment in the voltage level to make it 460v and speed of the engine should be

1200rpm, 60 Hz by adjusting rated speed in Woodward 2301A Control Box.

2) Synchronizing of Genertor.1 with 2, 3 was good but with No.4 there is a small problem solved

by changing actuator of No.4 and some adjustment in No.4 gain and droop potentiometers.The

problem was that No.1 takes the load and No.4 out of the board.

3) The operation of Genertor.3 with 4 was good but we did some adjustment in the gain and

resetting the Woodward to make the voltage stable.

4) The operation of Genertor.2 and 3 was good.

5) After that we were testing the operation of Genertor.2 with 4 and it was not good because the

load is not equally shared. We were following those steps to correct that:

a) Increasing rated speed in No.4 from Woodward.

b) Checking the potentiometer in the banal by removing wire 24 and measure the resistant of it

with 22 should be adjusted to 50ohms (adjusted by increase and decrease manually from the

panel).

c) Calculating how much time for pilot motor to fully rotate, it should be 1 min and 57 sec. all

alternators should be the same.

d) Measuring the load signal in Woodward and it should be equal in all generators if it is not

adjust it by increasing the load gain and droop in the Woodward.

SECTION5: SEA TRIAL After finishing the refit process for this ship the final step is sea trial to check the operation of

vessel. First we tested the generators 1, 2, 3 and 4 without load when it is stop. Second, we did

sea trial in clean area by paralleled two generators. We started at 11:30 A.M with generator.2 and

4. Then generator 2 and 3 at 12:21 P.M. After 45 mins generator.3 and 4. Finally we test all

generator (in parallel).

No Load Gen.1 Gen.2 Gen.3 Gen.4 Voltage (V) 469 469 465 470 Frequency (Hz) 59.98 59.98 59.97 60.01 Alternator Speed (RPM) 1196 1199 1196 1199

11:30 A.M. Full Load Gen.2 Gen.4 Voltage (V) 469 459 Frequency (Hz) 59.98 59.7 Alternator Speed (RPM) 1196 1196 Power Factor 0.72 0.9 Rated Voltage MVAR 0.3 0.11 Current (AMP) 889 843 Power (KW) 637 649 % of load 58% 59%

12:21 P.M. Full Load Gen.2 Gen.3 Voltage (V) 466 466 Frequency (Hz) 59.89 59.89 Alternator Speed (RPM) 1198 1198 Power Factor 0.75 0.8 Rated Voltage MVAR 0.22 0.22 Current (AMP) 819 866 Power (KW) 620 666 % of load 57% 62%

01:02 P.M.

Full Load Gen.3 Gen.4 Voltage (V) 457 457 Frequency (Hz) 59.89 59.8 Alternator Speed (RPM) 1196 1196 Power Factor 0.75 0.9 Rated Voltage MVAR 0.22 0.01 Current (AMP) 819 808 Power (KW) 620 633 % of load 57% 58% From the values we noticed that the values are around the rated values and they

are accepted. We did not face any problem in this sea trail any every thing was

excellent.

SECTION6: CLEAN POWER SUPPLIERS

I. INTRODUCTION

Equipment protection important today because of electronic equipment is more sensitive to minor

fluctuations and new electronic loads create conditions that didn’t exist before.

There are optional solutions for the problems which produced by electronic devices: improving the supply,

immunizing the equipment (protection) or controlling the disturbance (protection). Motor generator set and

UPS are used to solve those problems and they have advantages and disadvantages over this process.

The survey operations in KARAN 8 supply system to provide the following electric power.

220 \ 110 volts, 3 phase, 60 Hertz AC from Motor Generator Set

220 volts AC 1 phase uninterrupted power supply from UPS

II. SPACIFICTIONS

A. Motor Generator Sets

1. The power for the drive motors to be derived from the 460 volt, 60 Hz switchboard.

2. The LEROY-SOMER motor generator sets to be fitted, each having an output of 50 KVA

3. Motor generator sets to run at 1800 rpm.

4. Alternators to generate at 220V AC, 3 phase, 60 Hz. alternators to be fitted with AVR’s and adjustable

voltage controls.

5. Motors and alternators to have Class “F” insulation with Class “B” temperature rise, to AB.S. latest

regulation, at an ambient air temperature of 50°C, after 6 hour run at full load or a minimum of 2 hours after

the final temperature has stabilized.

6. The quality of the clean supply to be as follows:

Voltage

Nominal ± 1%

Maximum modulation ±2%

The transient characteristics to be such that when applying the largest load suddenly with a power factor of

0.4 or throwing the largest load off the voltage is to recover to ±1% within one second.

Frequency

Nominal 60 Hz

Constant load tolerance ± 0.5%

Modulation 0.25%

Wave Form

Maximum individual harmonic 3%

Maximum total harmonic content 5%

7. The AVR to maintain the voltage stable as specified above, with a power factor of 0.7 to near unity without

any external adjustment.

9. A control cubicle with all necessary instruments required for synchronizing, control and protection of motor

generator sets to be fitted adjacent to the machines. Controls to include a check synchronizer.

10. In the figure 1 show the connection of the motor generator sets in the ship.

B. 220 Volt DC Survey Equipment Uninterrupted Power Supply (UPS)

1. The uninterrupted 220 volt AC 1 phase power supply is to be sufficient capacity to supply all equipment

plus 50% capacity.

2. The Simenes UPS have an output of 10KVA and the battery capacity of 30 min.

3. The UPS and batteries unit to be housed in the space shown on the Guidance General Arrangement plan.

The batteries to housed on the wheelhouse top in well ventilated batter boxes shield from direct sunlight.

4. The 220 volt AC supply to be distributed via fuse protected distributed boards. The battery to be fuse

protected.

5. Visual and audible alarm with muting facility to come up on alarm system indicating that the 24 volt

system derived from the ship’s main failed and system is supplied by battery.

6. Items to be fed from the ship’s 24 V system are as follow:

Hyperfix, Microfix, Deso 25 E/S with heave compensators and Polar Track.

SECTION7: MOTOR GENERTOR SET I. GENERAL

Motor-generator sets consist of a motor driving an AC generator or alternator so that the load is completely

electrically isolated from the power line. In the past, in some cases DC or induction drive motors were used

requiring close speed control to maintain stable frequency to the load. The tendency nowadays is to use

synduction or synchronous motors. The synduction motor resembles an induction motor but runs at

synchronous speed. With either of these unit types, alternator speed and thus frequency to the load is as

stable as power line frequency. Motor generator sets can be a cost effective method of providing "clean"

power to sensitive equipment sharing electrical service with large motors or other loads that momentarily

disrupt the system's voltage. Also, it can be used as frequency converter. The flywheel effect provided by

the electric motor dampens or eliminates the temporary voltage dips or spikes on the primary electrical

service side.

The Machine comprises of a Motor and a Generator, both mounted on a common base plate and coupled to

each other through flexible coupling. A Control Panel comprising of a starter for the Motor, contactor for the

Generator and Meters and Instruments, is supplied with the frequency inverter.

Figure 2: Motor Generator Set

II. PARTS Motor generator set consists of 4 main parts as we see in the figure 3 below:

1. Synduction or synchronous motor

2. Flywheel

3. Generator

4. Control box (Frequency inverter)

460 V / 60 Hz Power supply pass through the Frequency inverter which control the motor supplying power

and this box feed the power to the motor which drive the alternator. Then the clean power will be produced

which will distributed by generator switchboard. Figure 4 and 5 illustrate that the connection of motor

generator and the parts list.

Figure 3: Main Parts of Motor Generator Set

III. VOLTAGE ADJUSTMENT BY COMPOUNDING TRANSFORMER

One of the methods for adjusting the voltage is by compounding transformer which is installed in alternator

control box that has 2 possibilities for adjustment: The air gap and the number of secondary turns.

A) Voltage adjustment at no load by adjusting the transformer air gap

- We adjusted the speed at a value of 3-4 % above the rated speed.

- Then, we noticed that the voltage at no load is low, and it was necessary to increase the air gap by loosen

the 3 bolts (1) as shown in figure below and inserting a screw driver between the coil face and the yoke (3)

at point (2) then separate the yoke to increase the air-gap, equally along the length until a voltage equal to

the rated voltage is obtained, then secure the bolts (1).

Figure 15: Compound

Transformer

B) Voltage regulation at load selecting the number of secondary winding turns.

The transformation ratio is adjusted by changing connections to the in put terminals of the secondary

windings. Each secondary coil has three separate windings consisting of (n) turns, 15 % (n) turns and 5 %

(n) turns. Thus, the number of turns in the secondary can be adjusted in step of 5 % from (n) -20 % to (n) +

20 %.

SECTION8: TESTING AND CERTIFICATES I. TESTING OF THE MOTOR GENERTOR SETS After finishing the maintenance request for this device Saudi Aramco did this test for the Motor

generator sets to check the performance of the set. The following tables present the test data for

both the motor and generator.

A. Record of the voltage, current and speed characteristic curves Sn Pn Un In fn cosφ

Gen. Type Reg. No. rpm KVA KW V A Hz

I LEROY – SOMER LSAM 44 M1 A1053431/02 1800 50 40 220 131.2 60 0.8

II LEROY – SOMER LSAM 44 M1 A1053431/01 1800 50 40 220 131.2 60 0.8

B. Dynamic Voltage and Frequency Response Gen. I Gen. II

Rated current (In) A 131.2 131.2

Generator protecting devices (In + 15%) A 150 150

delay in sec. sec 20 20

Sustained short circuit current (Iki) KA 0.393 0.393

Overcurrent protection (1.1-1.5* In) A 150 150

(t < 30s) sec 17 15

Setting of short circuit protection 300% KA 0.328 0.328

(1,5 In < Isetting < Iki, 300 - 800 ms) ms 800 800

KW -4 -4 Reverse power protection (10% Pn) (5 - 10 s) sec 9 10

Gen. I Gen. II C. Generator

load step test (96%) KW V A Hz KW V A Hz

0 0 222 0 60.01 0 221.9 0 60.01 25 10 221.4 24.5 59.96 10 221.3 28.6 59.96 50 20 220.9 51.5 59.9 20 220.6 54 59.91 75 30 219.8 79 59.84 30 219.4 79 59.85 100 40 218.6 105 59.78 40 217.2 108 59.81 110 100 75 30 219.5 77.3 59.8 30 219.1 79 59.75 50 20 220.7 50 59.91 20 220.1 52 59.91 25 25 221.3 26.5 59.96 25 220.6 27 59.95 0 0 222 0 60.01 0 221.2 0 60

Perm. Deviation 2.50% 5% 2.50% 5%

D. Loadsharing during parallel duty Load in % (Pn) 0 25 50 75 100 75 50 25 0

KW 0 11 19.5 29 39 30 19.4 9.8 0 Gen. I

A 0 24.1 49 76.6 101.9 78.8 49 24.4 0 KW 0 11 20.5 30.8 40.5 31 20.2 10.6 0

Gen. II A 0 29.5 56 85.2 110.8 86 55.1 29.6 0 V 221.6 221.1 220.6 219 217.9 219.4 220.5 221.3 221.7

Gen. I &II Hz 60.01 59.96 59.9 59.85 59.77 59.84 59.9 59.95 60.01

E. Dynamic voltage and frequency response Unit Gen. I Gen. II U V 220 219.4 at rated load f Hz 95.85 59.85

Umax V 224.8 223.2 Switching-off from 70 %

load at load breaking

fmax Hz 60.17 60.02 u V 221.8 221.4 at no load f Hz 60.01 60.01

Umin V 221.2 209.6 Switching-on from at least 50

% load at switching - on

f min Hz 59.83 59.82 U V 221 220.4 at 50 % load f Hz 59.9 59.9

Umin V 220.8 217.6 Switching-off from at least

50 % parrel load at switching - off

f min Hz 59.89 59.89 As we noticed that the values are around the rated values by ±3 % for different tests and that was

accepted.

II. CERTIFICATES FOR ELECTRICAL MOTORS This is certificates for motors according to the rules of “AMERICAN BUREAU OF SHIPPING”.

This is to certify that the undersigned Surveryor to this Bureau did, at the request of ABB Service A/S attend their plant at Oslo; Norway of the 22 nd day of October 1993 in order to examine

and report on two (2) electric motors manufactured according to manufacturer’s specification

and the rules of this Bureau.

Electric Motors

Type: LS 280 SP. T

Output: 50 KW

Voltage: 460 V 60 Hz

Speed: 1790 RPM Insulation class: F

Protection: IP 55 The motors were tested according to the annexed report with results considered satisfactory. The

motors were accepted subject to installation and testing on board to the satisfaction of attending

Surveyor.

Test Sheet 1. Nameplate

LS 280 SP. T

KW 50 Voltage 460 ∆ Amperes 87

C/S 60 RPM 1790 Working S1

2. Test Data

NO LOAD TEST

VOLTAGE 460 Ampere 49.3 Watt 4238

SHORT CIRCUIT TEST

VOLTAGE 50 Ampere 87.5 Watt 2688

VOLTAGE TEST 2000 for one min. RESISTANCE OF WINDINGS 0.05972/O, Ω /phase

INSULATION TEST 2000 M Ω INSULATION CASS F

3. The output of the above mentioned motor is based upon type test of motor

TYPE LS 280 SP. T NO.K 038891/01

KW 50.15 VOLTAGE 460

C/S 60 RPM 1791

Amp 87.8 ∆t 38.5 o C after 4 hours

Efficiency 91.80%

SECTION9: UNINTERRUPTIBLE POWER SUPPLY SYSTEM (UPS)

I. GENERAL DESCRIPTION

An Uninterruptible Power Supply is a device that sits between a power supply (e.g. a wall outlet) and a

device (e.g. a computer) to prevent undesired features of the power source (outages, sags, surges, bad

harmonics, etc.) from the supply from adversely affecting the performance of the device. In this part we

discuss the Siemens UPS system B 41.

Siemens UPS system B 41 is able to feed sensitive loads with AC power without interruption. The units are

delivered in the range 5 kVA to 30 KVA. The installations serve the following purposes:

• To bridge mains supply failures by using a battery.

• To act as voltage and frequency stabilizer.

• To prevent noise and voltage transients of the mains from reaching the load.

Typical field of application:

• Process control system computers in the industry.

• Data processing in banks and insurance companies.

• Power supply system controls.

• Telecommunication systems.

• Emergency lighting.

II. CONSTRUCTION

The main system modules of the B 41 UPS are assembled in a steel plate cabinet. For units with ratings 10

KVA and lower the battery in included in the cabinet. For bigger units the battery in delivered in a separate,

matching cabinet.

The UPS and battery cabinet contains the power circuits: Rectifier, Inverter, Static bypass switch (SBS),

Manual bypass and Battery. Figure below shows the Simplified power circuit diagram.

III. MODE OF OPERATION

A UPS system comprises the rectifier, inverter, static bypass switch (SBS) and the battery, permanently

connected to DC-link. Voltage and frequency may differ from those parameters of the rectifier.

A. UPS Block Operation (see the following figure 19)

a) Normal operation (rectifier – inverter): in this mode the load is supplied via the rectifier and the

inverter. The voltage of the mains supply will be converted in controlled rectifier. The inverter and

the battery are supplied with a regulated DC voltage. In static inverter the DC voltage is converted

in to an alternating voltage with constant voltage and frequency for feeding sensitive loads. The

battery voltage is controlled in order to keep the battery in a fully charged state.

b) Feeding via battery and inverter: if an interruption or distortions should occur in the mains supply,

the rectifier will be switched off. The battery takes over the supply of power to the inverter without

any interruption. The inverter electronics will then keep the alternating voltage constant, even

though the battery voltage decreases. As the mains recover the rectifier will recharge the battery

and supply the inverter. The battery will charged and normal operation reestablished.

c) Mains bypass operation: In the case of a heavy overload (inrush current or short circuit) or an

inverter failure, the static bypass witch (SBS) will automatically and without interruption transfer the

load to the mains. As the overload decreases below 100 % of the UPS rated power, the inverter will

start up and automatically take over the load without interruption. By means of the manual bypass

switch the unit can be shut down for servicing without disconnecting the load.

B. Operation under Abnormal Conditions

a) Over load: The unit is able to supply an overload sinewave current of 175% of nominal for a period

of 2 sec. subsequently 150% for 10 s. If these values are exceeded, the output voltage will be

reduced in order to keep the current within its limits. If the mains are available, the static bypass

switch (SBS) will transfer the load to the mains supply.

b) Load short circuit: The inverter is short circuit proof. During a short circuit at the load and without the bypass mains available the current will be limited to 200 % for 2 s and subsequently 180 % of

nominal current for 10 s.

c) UPS module failure: In the case of inverter failure, the load will be transferred to the mains supply

without interruption via the static bypass switch. This will occur provided the mains voltage and

frequency are within tolerance and that the inverter is in synchronism with the mains. If the mains is

out of tolerance, different actions are possible to choose by programming switches.

d) Overload/overtemperature: The inverter is equipped with internal temperature sensor. The

setting of a switch in the electronic will determine whether a warning signal is given or the inverter

is tripped. When the inverter trips, the load supply will commence from the bypass supply.

IV. MAINTANCE (BATTERY DISCHARGE TEST) A battery discharge test should be performed 1 to 2 times a year in order to verify the condition of the battery

bank.

1. Prior to this test the battery must be charged for 10 hours to ensure full capacity. Switch the rectifier off

(Q10) at rated load or maximum permitted load.

2. Read the DC-link voltage each minute. The cut off limit is preset to 316 V (±3V). A voltage below this limit

causes the inverter to be switched off and the SBS to be switched trough without any interruption of the

supply.

3. Determine if it is about time to exchange the battery by comparing the present discharge voltage curve to

prior test results. After ten hours charging the battery has regained its full capacity.

V. SELECTING UPS SYSTEMS

The Uninterruptible Power Supply (UPS) depends on the type and size of load you are trying to protect.

There are some critical aspects that should be considered:

First is the type and size of the Load. Three-phase loads are unsuitable for ringing systems, as are loads

with large start-up or in-rush currents. The size of the unit should reflect not only current loads, but also

plans for the growth of the system.

The second thing to consider is the Installation Location. UPS systems can make noise and give off heat.

The line interactive units are the quietest and coolest units. They may be more suitable for office installation.

The third thing to consider is Cooling. It is important to remember that computer systems will not run if they

get to hot. If you back up your computer and do not provide some means to keep the environment cool, it

may trip off line, and even damage the system. Do not put your cooling system on the UPS. Instead some

type of back-up generator should be used to power the cooling system.

Fourth, consider Lighting. To provide back-up power for lighting in the area where personnel will bring the

computer to an orderly shut down.

Fifth Batteries, in some cases the batteries will require their own storage cabinet; in others they will be

internal to the UPS. The most important point is the length of time required to bring the computer to an

orderly shut down. If you require extended run time you should consider coupling the UPS to a stand-by

generator.

Finally, the efficiency of the unit will let you know the operating costs for that unit. The higher the efficiency,

the lower the operating cost.

SECTION10: MOTOR GENERATOR SET OR (UPS)

I. POWER QUAILTY The concept of powering, grounding and protecting electric equipment in a manner that is suitable to the

operation of that equipment. In other words, doing what it takes to keep the electric supply to equipment

transparent or unnoticed.

Power quality problems can cause:

Equipment malfunctions

Excessive wear or premature failure of equipment

Increased costs from downtime

Increased maintenance, repair time and expense

Outside consultant expense

Equipment protection important today because of electronic equipment is more sensitive to minor

fluctuations and new electronic loads create conditions that didn’t exist before.

II. DISTURBANCES CAUSES PROBLEMS

• Interruptions (Outages & Blinks)

• Voltage Fluctuations (Voltage Sags & Swells)

• Transients (Really Fast Spikes, Surges, etc.)

• Waveform Distortion (Harmonics, Noise & Interference)

There are optional solutions for the problems which produced by electronic devices: improving the supply,

immunizing the equipment (protection) or controlling the disturbance (protection). Motor generator set and

UPS are used to solve those problems and they have advantages and disadvantages over this process.

A. UPS

• Advantages

– Continuous regulated power to load

– Higher system reliability

– Excellent output performance for sensitive loads

• Disadvantages

– Higher cost

– Lower efficiency

– Larger physical size

B. MOTOR GENERTOR SET

• Advantages

- Ride through many shorter interruptions.

• Inertia keeps the rotor rotating for 10-15 seconds after the power shuts off which is long enough to ride

through a high percentage of problems.

- Long Life

- Simple, rugged device

- Low harmonic distortion content at all load levels.

• Disadvantages

- Will not ride through extended outages.

- Degrade and fail gradually over time rather than all at once.

- Expensive for smaller systems

Finally, we described and evaluated both systems the MG set and UPS system and both of them have the

advantages and disadvantages over the clean power suppliers. From the features we can decide which

system we should use. The decision is based the applications, advantages over some systems and also the

cost. As we mentioned before, they used both systems in KARAN 8. The survey operations supply system

to provide the following electric power.

220 \ 110 volts, 3 phase, 60 Hertz AC from 50 KVA Motor Generator Set.

220 volts AC 1 phase 10 KVA uninterrupted power supply from UPS