Prince Mohammad Bin Fahd University
College of Engineering
Department of Electrical Engineering
Internship Report
at
[Saudi Electricity Company]
Reporting Period:
[13/07/2012 - 27/07/2012]
Submitted by:
[Sultan Hamed Al-Mutairi]
[200800298]
[submission date (27/07/2012)]
Electrical Engineering Department
Summer 2012
My name is Sultan Hamed AL-Mutairi, and my major is Electrical
Engineering. I am seiner student. I have Internship course with Dr.Omar
Ouda in this summer.
Summary
The progress report concerns with the engineering aspects that face the underground
medium voltage in the Saudi Electricity Company.
A power supply project is of two types, one is the low power supply and the other is the
high power supply. A low power supply project is when dealing below an apparent power
below 4 MVA whereas the high power supply is above 4 MVA.
A system improvement project is a project that deals with the company network to make it
more reliable and secure. The system improvement projects usually come when the load in
a 13.8 KV feeder/ cable is close to 8 MVA which is the maximum apparent power that the
feeder withstands in order not to be damaged. The report starts with a background of the
company medium voltage electrical equipment. Then, introducing the single line diagram,
where each project depends on.
1. Background
The first day of my training was in 16\6\2012 at SAUDI ELECTRICITY COMPANY
(SEC) in AL-Kobar. The SAUDI ELECTRICITY COMPANY (SEC) was established
in 2000. The company main job is to provide comprehensive electrical services
starting from the high voltage until reaching the low voltage.
The company can be divided in accordance to the power into three parts which are the
power planet, power transmission, and operation areas. In the power planet, a standard
voltage is generated and converted to higher voltages using step up transformers. The
power transmission is responsible to transmit the higher voltages to a desired region.
In operation areas, the high voltages are converted to a standard medium voltage
using step down transformers. This medium voltage is the interface between the
company and customers.
Training supervisor information:
SUPVR. PP. MAIN
Name: A. SALAM AL-MULIA, Email: [email protected]
The company's training schedule:
During the summer training period, four divisions will be attended in the medium
voltage which are the Maintenance, Operation, Engineering, and Planning and
Construction Division. The duration of the training period in each division is two
weeks except the Maintenance division are three weeks.
The Planning and Construction Division deals with the power supply and the system
improvement. Also, this division is responsible for providing bulk customers with
relay settings for their switchgears. The training within The Planning and Construction
Division will complete next week and the week after training will be within The
Operation Division.
2. Meters
Meters are the SEC interface with customers. There are two types of meters for low
voltage customers, one is the regular meter and the other is the service box shown in
Fig.2.1. The regular meter and the service box give the electrical consuming in
kilowatt hour (KWH). The regular meter circuit breakers range from 30A to 160A.
When dealing with higher than that, a service box meter is used up to 400A. The
service box contains a current transformer that transforms the high current that is
impossible to be read by the regular meter, into a low current in which the meter can
read without being damaged. Also, each service box has a multiplying factor where
the operator takes the reading from the meter and multiplies it by the multiplying
factor to give the actual reading.
(1)
(2)
Figure 2.1: Types of low voltage meters; (1) regular meter and (2) service box.
For high voltage customers, upper than 400A circuit breakers, SEC uses a metering
unit shown at Fig 2.2. Its method for reading the consumed electricity does not differ
from that in the service box. However, the metering unit differs from the service box
that it has a relay.
Figure 2.2: Metering unit with a multiplying factor of 13800/115.
The regular meter takes the input circuit from a mini pillar but the service box usually
takes it directly from the low voltage panel. The meter is a meeting point between the
customer and the company. The normal customers are provided with two phases of
cables in addition to one neutral cable in one circuit. In the case when the service is of
220V/380V, connecting phase to phase gives 380V and connecting phase to neutral
gives 220V, and in the case of 127V/220V, connecting phase to phase gives 220V and
phase to neutral gives 127V.
Meters cab be connected in parallel not in series because customers need their voltage
to be fixed to operate their applications.
3. Power Supply to SHLUMBERGER on Dhahran Abqaiq Road
Problem: This project is about a power supply to SHULUMBERGER of 3 MVA.
Description: The project is about a low power supply because it is below 4 MVA and
the customer must be provided with one feeder. However, there is no source to supply
the customer.
Requirements: It is required to look for another feeder or to apply system
improvement.
Solution: A better suggest was to provide SHULUMBERGER a source of supply
through ARAMCO and ARAMCO approved to supply SHULUMBERGER .So, the
project concluded that SHULUMBERGER has to supply and install 13.8KVA 3x300
mm2 Aluminum conductor cable 700 m long including termination at both ends and
directional drilling across DHAHRAN ABQAIQ high way, in order to connect to
ARAMCO network. Fig.3.1 shows how cabling is provided and the customer room
for switchgear installation. SEC's job is to install the ring main unit and the metering
unit at S/S 34029. SHULUMBERGER has to supply and install switchgear with
circuit breaker and relay at SHULUMBERGER switchgear room including interface
cable between SEC's switchgear and SHULUMBERGER's switchgear.
(1)
(2)
Figure 3.1: SCHLUMBERGER project: (1) The location of SEC switchgear, and (2) The single line
diagram for the project.
Cost Estimate Analysis:





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Material cost: 59,903.09 SR.
Material overhead (25%): 14,957.77 SR.
Labor cost: 828.00 SR.
Total net cost: 75,706.86 SR.
Total overhead (20%): 15,141.37 SR.
Overall total cost: 90,848.23 SR.