Eastern Mediterranean University Electrical & Electronic Engineering Department Summer Training Report Felix Wani Demetry 17700215 February 2021 Name of Company: South Sudan Electricity Corporation Address of Company: Juba, South Sudan Supervisor of Training: Alberto Lado Address of Supervisor Tel: +211954530209 albertol@yahoo.com Field of Training Operation & Maintenance Number of Engineers & Their Fields 5 Electrical Engineers Date of Training: 8 July – 30 August 2018 No. of Working Days: 40 1 Acknowledgements I would like to use this opportunity to acknowledge my family for their overwhelming support and the Department of Electrical Electronics engineering of the Eastern Mediterranean University, most especially my summer training supervisor and the entire team at South Sudan Electricity Corporation. May Gods peace abide be with you all at all times. 2 Table of Contents Acknowledgements ................................................................................................................................. 2 List of figures .......................................................................................................................................... 3 1. Introduction ..................................................................................................................................... 5 2. Electrical Maintenance ........................................................................................................................ 6 2.1 What is Electrical maintenance? ..................................................................................................... 6 3. Preventive Electrical Maintenance ....................................................................................................... 7 5. Pole or support (high tension) .............................................................................................................. 9 What is a pole? ........................................................................................................................................ 9 8. Automatic transfer Switch (ATS) ....................................................................................................... 12 8.1 A brief introduction ..................................................................................................................... 12 8.2. How to install an ATS ................................................................................................................. 13 9. Maintenance Tools ............................................................................................................................ 14 Fig 6.4. showing pier of Allen keys set .................................................................................................. 18 10. Sockets outlet .............................................................................................................................. 20 11. Plug top ........................................................................................................................................... 21 12. Mounting television on a wall ...................................................................................................... 22 12.1 procedure ................................................................................................................................... 23 Conclusion ............................................................................................................................................ 24 References............................................................................................................................................. 25 List of figures Fig 1. Conducting maintenance on a control panel...………….………………………………………………….6 Fig 2. Trainees getting educated on RMU……………………………………………………………………………..….7 Fig 3. Concrete H.T pole replacement……………………………………………………………10 Fig. 4 situation on load shedding ………………………………………………………………..10 Fig. 5 A type of ATS switch (Cabinet Style) ……………………………………………………………………………12 Fig 5.1 Wall mounted style ATS switch…………………………………………………………………………..………13 3 Fig. 5.2 ATS circuit ……………………………………………………………………………………………..…………….....14 Fig 5.3. Internal diagram of ATS switch…………………………………….……………………………………………14 Fig 6. Best digital multimeter………………………………….……………………………………………..………………15 Fig 6.1. Electrician pair of plier……………………………..……………………….…………………………16 Fig 6.2 Long nose plier……………………………………………………………………………….………………………….16 Fig 6.3. Insulated adjustable spanner………………………………………………...…….....…….17 Fig. 6.4 Pair of Allen keys set……………………………………………………………………………………………………18 Fig. 6.5 Practical tool ratchet set………………………………………………………………………………………………19 Fig. 6.6 Cordless electric drilling machine ……………………………………………………...19 Fig 7. Connecting a double gang power outlet……………….…………..………………………………………….…20 Fig 7.1 Connection of 2-way gang switch……………..…….……...…………………………………………………..21 Fig.8 A 15A fused plug…………………………………………………………………………………………………………...21 Fig. 8.1 The burnt plug…….……………………………………………..………………………………………………………22 Fig. 8.2 Various types of plugs and sockets…………………………….…………………………………………….23 4 1. Introduction South Sudan Electricity Corporation (SSEC) is the only public owned power utility company responsible for generation, transmission and distribution of electricity to the people of south Sudan. South Sudan Electricity Corporation was establish in 2012 under the ministry of Energy and Mining following the split from Sudan and gaining independence the year before. In January 24, 2014, the SSEC was approved for a grant from the African Development Bank Group to rehabilitate and expand the distribution networks in Juba. 1.1 My training During my training days with the power utility service provider at the (SSEC) south Sudan electricity corporation, I worked at the distribution department under the team of electrical operation and maintenance engineers that works day and night to make sure electric power is constantly supplied to the consumers. The operation and maintenance section is responsible for transformers fuse replacement both on the high tension and low tension, distribution line fault finding, disconnection of customers, load shading, tress pruning along powerlines etc where by in my 40 days of training I spent at the south Sudan electricity corporation, one of the major things was team-work, which was beneficiary and experience worthy. 5 2. Electrical Maintenance 2.1 What is Electrical maintenance? Electrical maintenance covers all aspects of testing, monitoring, fixing, and replacing elements of an electrical system. Usually performed by a licensed professional with a complete knowledge of the National Electric Code and local regulations. Scheduled test is very important to make sure appliances and devices connected to the electrical system are safe to use for everyday needs. How to carry out electrical maintenance. A simple electrical maintenance can be done by following these few steps Checking for damaged wires and replacing them if needed Checking for broken power line poles Checking for rodent to prevent shorting the circuit Testing fuses, circuit breakers and control panels Fig 3: conducting maintenance on control panel 6 3. Preventive Electrical Maintenance 3.1 introduction Early identification of problems is a key aspect of electrical maintenance. For instance, should a back-up generator sit idle until needed, it may not start due to a number of factors. Old fuel clogging a fuel filter, uncharged starting batteries, or start switches left in the wrong mode can all prevent a smooth transition to backup power. These are basic problems, easily identified and addressed through preventative maintenance. One of the major challenges to electrical maintenance is the nature of electrical wiring. It can be difficult to pinpoint the location of specific problems as the system is built on long distances or rather into the building. Ring main unit and thermal imaging has become increasingly important in the industry for its ability to identify faults with both electrical connection points and equipment. By catching such problems early, electrical maintenance helps reduce unexpected power outages and protects the expensive equipment from damage. What is electrical maintenance? It’s an aspect of building operations no commercial facility should be without. While large scale operations may have their own on-staff electricians, smaller facilities may find it more financially viable to contract with a licensed professional for scheduled electrical maintenance and servicing. Fig 2 Figure showing trainees getting educated on RMU 7 4. Health and Safety at Work Electricity is a familiar and necessary part of everyday life, but electricity can kill or severely injure people and cause damage to property. There are simple precautions when working with, or near electricity that can be taken to significantly reduce the risk of electrical injury to you and others around you. 4.1 Electrical systems and equipment are required to be constructed of materials that are suitable (both mechanically and electrically) regularly, effectively and safely maintained afforded suitable protection against adverse conditions (mechanical, electrical and environmental damage) correctly installed and used provided with suitable earthing and protective devices provided with a suitable physical means for disconnecting and isolating the supply 4.2 Hazards Electrical hazards are associated with: the fixed installation electrically powered tools portable electrical appliances Leads, connectors and other components of electrical tools and appliances. 8 4.3 Overhead and underground electricity lines Before starting any work near overhead and underground lines, you need to assess the risks and plan how these will be managed: Overhead lines: heights, sway and sag of lines nature, height and shapes of loads Approach distances and work zones. Underground lines: identify cable location, for example if you’re going to repair pot-holes talk to asset owners Use insulated hand tools. 5. Pole or support (high tension) What is a pole? A pole is a column or post used to support overhead power lines and various other public utilities, such as electrical cable, fiber optic cable, and related equipment such as transformers and street lights. It can be referred to as a transmission pole. Electrical wires and cables are routed overhead on poles as an inexpensive way to keep them insulated from the ground and out of the way of people and vehicles. The poles can be made of wood, metal, concrete, or composites like fiberglass. They are used for two different types of power lines: sub transmission lines, which carry higher voltage power between substations, and distribution lines, which distribute lower voltage power to customers. Utility poles are commonly used to carry two types of electric power lines: distribution lines (or "feeders") and sub-transmission lines. Distribution lines carry power from local substations to customers. They generally carry voltages from 4.6 to 33 kilovolts (kV) for distances up to 30 miles, 9 and include transformers to step the voltage down from the primary voltage to the lower secondary voltage used by the customer. A service drop carries this lower voltage to the customer's premises. Fig.3 figure showing concrete H.T pole replacement 6. Load Shedding Load shedding is normally carried out when the power demand is more than the power availability at a given point of time to shed excess load on the generating stations. Load shedding is carried out on priority basis. Emergency services such as hospitals, fire services, important government office etc. are left out and load shedding is carried out phase by phase. Thus the switching ‘OFF’ of particular feeder (circuit breaker) to avoid total breakdown due to overload is called shedding. During my training period the load shedding normally was carried out (manually by the operation team as the network is yet to be upgraded with sophisticated equipment) between 10:00 am to 15:00pm and as well in the evening hours between 19:00 to 22:00 hours. Fig. 4 showing situation on load shedding 10 7. Conductor Jointing The length of distribution lines are in kilometers and one coil of conductor is not able to solve the length problem. Hence jointing the conductor is necessary. Another necessity of jointing the conductor is breaking of the conductor for some reason like short circuit or car accidents as it normally happen. 7.1 Types of Joints I. Britannia Joint: This type of joint is made only on solid conductors and cannot be made on stranded conductor. Two conductors of length 6 inches (150 mm) are brought in front of each other to be joined. Then both conductors should be cleaned to make sure that they are rust free. If the conductor is of copper; it should make good electrical connection. Then ends of both the conductors are bent through half centimeter and placed on each other. The length of the contact portion should be minimum 100 mm. This joint should be bound by 14 mm copper wire. II. Telephone Joint (Western Union): This joint is used only for solid conductors. It is used for conductors of size 8 SWG or higher size. First, they are bent at 100 to 125 mm from the edges and are placed over each other. Then each one is twisted with another conductor. III. Married Joints: This joint is made between copper conductors having central strand of G.I. wire. This joint should not be made between Al conductors. Approximately 175 to 200 mm of conductor strands are unwound. The G.I. strand of both conductors should be broken up to a length of 175 mm. Both conductors should be brought in front of each other and their strands should be woven with each other. The strand of one conductor is twisted on another conductor, and the strand of the other conductor is twisted and then soldered. This is used only for small span length. IV. ‘T’ Joint: This joint is made with stranded conductor. This joint cannot take tension. It is used for jumper or tapping in sub-station. The conductor strands to be separated up to 100 mm. Then middle steel strands are cut. Then it shall be placed to horizontal conductor with three strands each on either side and shall be twisted over the horizontal conductor. 11 V. Sleeve Joint: It can be made with any type of aluminum conductor. Graphite grease is applied over the conductor and two Al sleeves should be taken. These sleeves should be placed on the conductor as shown. Sleeves should be twisted by twisting wrench. This joint is made for L.T., H.T., ACSR, AAC conductor up to 0.06 cm2. VI. Compression Joint: This joint is used for conductors of more than 0.06 cm2 sizes. For preparing these joints, two different sleeves are used. 8. Automatic transfer Switch (ATS) 8.1 A brief introduction ATS or AMF (Automatic mains failure) switch is a device that detects when there’s power failure at the mains and sends a signal to the secondary supply to power it. It is used to automatically switch between the primary source of power to the secondary source of power when there’s failure on the primary side. There are various kinds of ATS’s that can be chosen from to satisfy one’s specific need. Different kinds of ATS switches shown below: Fig 5. A type of ATS switch (Cabinet Style) 12 Fig 5.1. Wall mounted style ATS switch 8.2. How to install an ATS Firstly, choose an appropriate place to mount ATS suitably a place that can protect it from harsh weather conditions and mount the ATS. After the ATS is connected, Connect the mains supply and the secondary supply to the ATS then connect the ATS to the building to be powered. A communication cable which sends 12v is connected from the ATS to the Stand by generator which keeps its battery charged and powers it on and off. And the connection is ready. 13 Fig 5.2 showing ATS circuit Fig 5.3. Internal structure of ATS switch 9. Maintenance Tools Because tools play a very important role in the life of engineers, it is important that they are well kept and maintained. These can be done by ensuring the tools are always in a dry place, and all are wiped down after use. They are also stored in a proper and visible place as they can cause harm. It is also important to select the materials of the tools based on the conditions they’ll be working on; below are of the important tool for electrician. 14 9.1 Multimeter (recommended) A mustimeter capable of reading up to 600 volts is necessary. It should also be able to detect continuity. A clamp on style of mustimeter with amperage capability is preferable. Fluke is the preferred brand, although cheaper brands are available and will be adequate for the apprentice who is just becoming an electrician. Fig 6. Showing best digital multimetre fluke 15 9.2 Electrician plier Electrical pliers are used when working with electricity and making electrical connections. Special cutters on the pliers allow them to be used to cut wire to length and to strip away the wire's outer coating as well. Fig 6.1 showing electrician quality plier 9.3 Long nose pliers Long-nose pliers (also known as pointy-nose pliers, needle-nose pliers, pinch-nose pliers or snipenose pliers) are both cutting and holding pliers used by artisans, electricians, network engineers and other tradesmen to bend, re-position and snip wire. Their namesake long nose gives excellent control while the cutting edge near the pliers' joint provides "one-tool" convenience. Because of their long shape they are useful for reaching into small areas where cables or other materials have become stuck or unreachable with fingers or other means. Fig 6.2 showing long nose plier 16 9.4 Adjustable spanner An adjustable spanner or adjustable wrench is an open-end wrench with a movable jaw, allowing it to be used with different sizes of fastener head (nut, bolt, etc.) rather than just one fastener size, as with a conventional fixed spanner. It is one the most desired tool by every engineer. Fig 6.3 showing insulted adjustable spanner 9.5 Allen Wrenches (hex keys) A hex key or Allen key, is a simple tool used to drive bolts and screws with hexagonal sockets in their heads. The tool is usually formed of a single piece of hexagonal rod of hard steel, with blunt ends that are meant to fit snugly into the screw's socket, bent in an "L" shape with unequal arms. The tool is usually held and twisted by the long arm, creating a large torque at the tip of the short arm. Reversing the tool lets the long arm reach screws in hard-to-reach places. Each key is meant to be used with screws of a specific socket size, with rather tight tolerances; so the tool is commonly sold in kits that include half a dozen or more keys of different sizes. Usually the length of the key increases with the size of the socket, but not necessarily in direct proportion. Variants of the tool have the short end inserted in a transverse handle, which may contain multiple keys that can be folded into the handle when not in use. 17 Fig 6.4. showing pier of Allen keys set 9.6 Socket set (ratchet) A ratchet incorporates a reversible ratcheting mechanism which allows the user to pivot the tool back and forth to turn its socket instead of removing and repositioning a wrench to do so. The ratcheting mechanism allows the nut to be tightened or loosened with a reciprocating motion, without requiring that the wrench be removed and refitted after each turn. Typically, a small lever on the ratchet head switches the wrench between tightening and loosening mode. These drive fittings come in four common sizes: 1⁄4 inch, 3⁄8 inch, 1⁄2 inch, and 3⁄4 inch (referred to as "drives", as in "3⁄8 drive"). Despite being denominated in inches, these are trade names (common product name), and manufacturers construct them to 6.3 mm, 9.5 mm, 12.5 mm and 19 mm, having been rounded to a reasonable, if haphazard, metric value. Larger drive sizes such as 1 inch and above are usually only encountered on fasteners of larger industrial equipment. 18 Fig 6.5 showing practical tool ratchet set 9.7 Drilling machine A drilling machine or drill is a tool primarily used for making round holes or driving fasteners. It is fitted with a bit, either a drill or driver, depending on application, secured by a chuck. Some powered drills also include a hammer function. Drills vary widely in speed, power, and size. They are characteristically corded electrically driven devices, with hand-operated types dramatically decreasing in popularity and cordless batterypowered ones proliferating. Drills are commonly used in woodworking, metalworking, construction, machine tool fabrication, and utility projects. Specially designed versions are made for medicine, space, and miniature applications. Fig 6.6 showing cordless electric drilling machine 19 10. Sockets outlet A socket or power outlet or electrical outlet or receptacle is a socket that connects electrical appliances to an electricity supply. In buildings, electrical outlets are usually installed in the wall, although they can also be installed on the floor. A single socket outlet has three holes live denoted ‘L’, neutral denoted ‘N’ and earth denoted ‘E’. The Blue wire is connected to ‘L’, black wire is connected to ‘N’ and green is earthed. The wires are drawn from the socket to the next repeating the process till it’s all done. Fig 7. Connecting a double gang power outlet Fig 7.1. Showing 2 way gang switch wiring 20 11. Plug top A plug is used to connect an electrical device to an electrical outlet. There are different plugs for different socket types and they have different ratings from 3A-15A. To change a plug top, cut off current to prevent electrocution remove the wires from the bad plug, connect the red or brown wire to the live pin, the blue or black wire to the neutral pin and the green or yellow wire to the earth pin. Though a circuit will work without earth, the primary purpose of earth is to reduce the risk of serious electric shock from current leaking into uninsulated metal parts of an appliance, power tool, or other electrical devices. Fig 8. Showing 15A fused plug (best for electrical safety) Fig 8.1 showing burnt plug top 21 Fig 8.2 showing various types of plugs tops and sockets 12. Mounting television on a wall Televisions are a great way for announce information or for entertainment. They can be easily kept on a stand or anywhere that is not a danger to the device. But to hang it on a wall, becomes complicated and usually requires extra set of hands. To mount a TV on a wall, the following are needed: Drill Wall bracket (Usually from TV manufacturer) Screws Wall anchors Screwdrivers 22 12.1 procedure After locating where TV is to be mounted, Place bracket on the wall 180 degrees on the wall Mark screw holes on the bracket with a pencil Place wall anchors in the holes and fasten bracket to wall with the screws Hang tv on bracket following manual instruction. 23 Conclusion In my conclusion, training at the (SSEC) south Sudan electricity corporation was a truly memorable experience that I am truly grateful for. Seeing so many things I have learned in lectures being put to practice is an evocative experience. Courses like power generation and distribution, Electromagnetics etc were especially useful in this field. When the engineers and technicians spoke of certain terms or practices we were undertaking in the field I would often try to recall the thoughts of my lectures. This experience therefore gave me an idea of what I want to do in future. I have always enjoyed dealing with current and voltages in the theoretical aspect. I believe the power industry has also reignited my interest and grown it from a more theoretical knowledge into a more practical one. As an aspiring engineer I’m certain to the knowledge I have acquired in lectures from Eastern Mediterranean University and the experience I acquired from my summer training will make me a competitive engineer. One who is not simply content in working in the power industry, but also to improve the power sector using advance and smart technology. 24 References [1] https://en.wikipedia.org/wiki/ [2] https://en.wikipedia.org/wiki/South_Sudan_Electricity_Corporation [3] Transfer Switches https://en.wikipedia.org/wiki/Transfer_switch 25
