Internship Report 1 Page Prince Mohammad Bin Fahd University College of Engineering Department of Electrical Engineering Internship Report at [Sabic- Sharq] Reporting Period: [16/6/2012 – 8/8/2012] Submitted by: [Khalid AL-Hussain] [200700263] [submission date (15/9/2012)] Electrical Engineering Department Summer 2012
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Internship Report
1Page
Prince Mohammad Bin Fahd Universi t y
C o l l e g e o f E n g i n e e r i n g
Department of Electrical Engineering
Internship Report
at
[Sabic- Sharq]
R e p o r t i n g P e r i o d :
[16/6/2012 – 8/8/2012]
S u b m i t t e d b y :
[ K h a l i d A L - H u s s a i n ]
[ 2 0 0 7 0 0 2 6 3 ]
[ s u b m i s s i o n d a t e ( 1 5 / 9 / 2 0 1 2 ) ]
Electrical Engineering Department
Summer 2012
Internship Report
2Page
Abstract:
The importance of this internship is gaining experience, information, Knowledge and
Practical skills as much as I can for about two months. This report is demonstrating
my efforts in Sharq Company, its department, products, substations, Plants, my plan
for the internship, and the tasks and responsibilities. Further, its applications about
electrical engineering, plants and Substations are good for the engineer to relate the
theory to practical life. The information was from my experience at working in the
company, manuals, reliable books and some assistance from the engineers in Sharq.
The internship period was so beneficial that I covered the majority of the power
system information.
Internship Report
3Page
Table of Content
Introduction: 5
Acknowledgement: 6
Switch Gear: 7
Motor Control center (MCC): 7
Charger: 8
UPS: 8 a. Power Factor Study: 8
b. Load Flow Calculations: 8 c. Short Circuit & Voltage drop: 9
Conditions of calculations: 9
d. Cable Sizing Calculations: 9
Basic Training: 9
Fluorescent lights: 9
Mercury Vapor and Sodium: 11
Single Phase Motor: 11
Gas insulated switch gear (GIS): 11
Generators: 12
Cathodic protection: 12
The Impressive Current method (ICCP): 12
Sacrificial Anodes Cathodic protection: 12
VVVF: 13
Description about the component of VVVF 13
Protection System: 11
Some Protection devices in brief: 11 CT: 11 PT: 11
Differential relay (Relay 87): 11
Example for differential relay: 15 Synchronism Relay (Relay 25): 15
Fuses: 16
The Company: 16
Sharq Safety: 16
Root cause analysis: 17
RCA steps: 17
Internship Report
1Page
Heat Stress Announcements: 17
Conclusion: 21
Internship Report
5Page
Introduction:
During training at Sharq, I was assigned to visit substations and plants in order to
relate whatever in theory to practical life. The nature work of electrical engineering
needs some policies and cautions. Therefore, attending the safety lecture of the
company is for saving yourself and the environment. The importance of this
internship is learning and gaining experience to see how the practical life going about
my field, how to deal with some technical problems, how test emergency machines by
weekly or monthly. Ultimately, the engineer must seek for the information by himself,
so he won't forget it.
Internship Report
6Page
Acknowledgement:
Accomplishing this assignment was a very challenging goal in my life especially
being a first time at a workplace. It could not have been destined to become a reality
without those who have supported me throughout my way, for those I express the
below thanks:
Firstly, my appreciation to Almighty Allah for his endless blessings and for providing
me with health and strength to attain this degree.
Secondly, my utmost gratefulness and love to my mother who never cease or get
bored of blessing me with her prayers, may Allah reward her with the best in this life
and the life thereafter.
Last but not least, the engineers of Sharq company who assisted me a lot. First, my
supervisor Abdullah AL-Baghdadi was assisting me as much as he can, so I can get
benefits. Also, Mr. Pawan helped me in protection system. Sampath, was helping me
to understand the cathodic Protection. Jaber AL-Malki was helping me in
transformers.
.
Internship Report
7Page
Switch Gear:
Switch gear is combination of circuit breakers to feed whatever is needed. It can feed
transformers, substations, plants, etc. (See figure 1). There are three switch gears in
their substations in terms of voltage level in their substations such as Medium Voltage
Switch gear (4.16 KV), low voltage switch gear (480V) and High voltage switch gear
(13.8 KV). Each switch gear has GE Relays such as 750 relay for the feeders, 745 for
the transformers, and the 469 relay for the motors. Also, switch gears has ATS, and
Relay test blocks which used for testing the relays.
Figure 1
(Switch Gear)
Motor Control center (MCC):
It's the same as switch gear, but it has contactors instead of circuit breaker and fuses
for protecting over currents. Of course, the Multilin 469 is a part of it.
Figure 2
(MCC)
Internship Report
8Page
Charger:
a. Description: System which is useful to charge the dc controls during any
interruption. Further, the battery will charge the interrupted dc control switch
for a limited time during its interruption
b. Circuit: There is an input MCCB switch will make the rectifier to convert
from Ac to dc to charge a battery f. If any dc control switch fails, the battery
will feed it.
UPS:
Description: it’s uninterrupted power supply, which mainly used as a backup power
supply. If any interruption of ac equipments, motors, or valves, the UPS can feed
them when they are interrupted.
Circuit: The Rectifier will convert from ac into a dc for the battery, and then inverter
will convert from dc to ac again. If this operation fails, the bypass MCCB will work
by static switch. Then, it will send a signal to transformer and ultimately it will save
our plants from interruption.
Figure 3
(UPS & Charger)
a. Power Factor Study:
If the load is inductive, the capacitor enhances the voltage, reduces the current,
reducing line losses and reducing power bills and thus leading unity power factor.
Capacitor useful as a storage element and if it's a series with an inductor, it will
maintain the voltage.
b. Load Flow Calculations: Load flow calculation is about studying Voltage Profile, Power Flows, Current Flows,
Power Factors, Transformer LTC Settings, Voltage Drops, Generator’s Mvar Demand
(Qmax & Qmin), Total Generation & Power Demand, Steady State Stability Limits,
MW & Mar Losses.
Internship Report
9Page
c. Short Circuit & Voltage drop: Short circuit occurs between two phases or phase ad ground as a result of weak
insulation resistance.
Conditions of calculations:
1. Drawing the equivalent of per unit impedances for each element of the circuit.
2. Impedance of transformers, cables, bus ducts, etc. are required. But the
impedances of transformers, etc. are neglected.
3. Calculating mathematical equations to calculate the percentage drop. And
Ideal Circuit analysis theory for the calculating the short circuit current.
Note: Each of studies has its own calculations, but the most important point is to
convert the actual circuit into per unit and then calculates what is required.
d. Cable Sizing Calculations:
Procedure of calculations:
1. Calculating the continuous current.
2. Calculating the voltage drop across the cable.
3. Calculating the Maximum length of cable.
Basic Training:
I was assigned to attend the basic training course about my field in order to gain my
experience about electrical engineering. There are many information are very
impressive to learn in terms of practical life. This course covered street light and some
kinds of motors.
Fluorescent lights:
There are two types of fluorescent lights. The first is t is preheat type, when the circuit
is energized the current will flow from cathode A and then to cathode b through the
starter. Then, a heat will affect the gas inside the lamp and thus an arc will occur
across the fluorescent lamp. The second is the rapid type; the ballast will deliver a
small voltage to heat the cathodes. There isn't starter needed. Cathodes will heat the
gas, so the gas will be increased and higher current and lower resistance.
Internship Report
11Page
Figure 4
(Preheat Light)
Mercury Vapor and Sodium:
The ballast will deliver a voltage to the electrodes. The starter resistor will control the
current flowing. An arc will be struck between the starting electrode and the two main
electrodes. Therefore, the current will be high and resistance and that makes the
mercury vapor increased. Ultimately, the lamp is working. Sodium vapor doesn't have
the starting resistor and electrodes, but only two main electrodes. However, there is an
igniter that will deliver high voltage and high frequency to the electrodes and heat the
sodium vapor and arc will occur to make the lamp work. (See figure 5 & 6)
(Figure 5)
Mercury Vapor
(Figure 6)
Sodium Vapor
Internship Report
11Page
Single Phase Motor:
The supply voltage will deliver current which will go into two loads. The first load
has Capacitor, Centrifugal switch and starting winding. The second load has running
winding. The current will flow through the capacitor and centrifugal switch and then
starting winding. The starting winding will produce a magnetic field to make the rotor
rotate. When the rotor reaches the required speed, the centrifugal switch will open.
The running winding will make the rotor to continue rotating. The purpose of having
the capacitor in the circuit is maintain the wattage, voltage , and also to make phase
shift between the running period and starting period is 90. (See Figure 7)
(Figure 7)
Single phase motor
Gas insulated switch gear (GIS):
GIS is the upstream of the substations. A gas (SF6) insulated substation may have
underground feed lines and be nearly invisible to the average person. Distribution
circuits supplied by gas insulated substations normally have an alternate feed from
another substation, to allow maintenance work on the gas insulated site. For instance,
Sceco is feeding Voltage to Sabic Company, then GIS will feed transformer to feed
substations. Furthermore, the SF6 circuit breaker is available in the GIS because it's
useful for the high voltage sides. (See figure 8).
Internship Report
12Page
(Figure 8)
GIS in ABB Company
Generators:
There are many sources of generations such as Hydroelectric, nuclear, natural gas,
fossil fuel and diesel engine. Indeed, the generator is converting from mechanical
energy to electrical energy according to the first law of thermodynamic.
Cathodic protection:
Cathodic protection is technique which is useful to protect the buried pipelines, Metal
tank, and reinforced concrete structure from the corrosion. Usually the anode part "the
positive part" is for decaying and the cathode part for protecting the metal product and
that's why it's called Cathodic protection. Two methods are useful in cathodic
protection and these methods are the Impressive current and the sacrificial anode.
The Impressive Current method (ICCP):
The Impressive Current Cathodic Protection systems use anodes connected to a DC
power source. The rectifier bridge is useful to convert from ac source to dc powers
source. At the end of the rectifier bridge, there are two terminals. The positive
terminals for the anode for decaying and the negative terminal are for the cathode for
protection.
Sacrificial Anodes Cathodic protection:
There is something known as Fe and if it's added to a carbon, it will become hard
steel. In addition, the magnesium will be a good solution to avoid the corrosion. The
magnesium can be considered as the anode part for decaying, and the steel can be