Understanding Electrical Diagrams PDF

A SABIC and Mobil Yanbu Petrochemical Company Joint Venture UNDERSTANDING OF ELECTRICAL DIAGRAMS JAD-LC-A3-YP-EMT-LM-02 Frontline Development Program - JADEER STRICTLY CONFIDENTIAL Classification: Internal Use CONTROL PAGE DISCIPLINES SECTION...

A SABIC and Mobil Yanbu Petrochemical Company Joint Venture UNDERSTANDING OF ELECTRICAL DIAGRAMS JAD-LC-A3-YP-EMT-LM-02 Frontline Development Program - JADEER STRICTLY CONFIDENTIAL Classification: Internal Use CONTROL PAGE DISCIPLINES SECTION TOPIC LEARNING OBJECT TITLE ASSIGNMENT Electrical Electrical Electrical Diagram To understand philosophy Technicians of Electrical diagram and it’s components DOCUMENT REFERENCE # CONTROLS JAD-LC-A3-YP-EMT-LM-02 REVISION # ISSUE DATE: NEXT REVIEW DATE: 2022.0 18-Aug-2022 17-Aug-2025 DEVELOPED BY: REVIEWED BY: APPROVED BY: (SUBJECT MATTER EXPERTS) (REVIEW PANEL) (AREA OWNERS/SME LEADERS) Marwan Owaidhah, Electrical Trainer/ Ali A. Fallatah, Specialist Electrical, Abdullah Saleh Al-Ghamdi, I&E 12943 Maintenance /12610 Specialty Manager, Maintenance/21528 Ahmed Haresi, Specialist Electrical, Maintenance /33423 2 Classification: Internal Use TABLE OF CONTENTS PAGE SN SUBJECT NUMBER 1 Electrical Diagrams Introduction 5 2 Electrical Diagrams Symbols and Abbreviations 8 3 Protection Device Function Symbols and Abbreviations (Numbers) 11 4 Single Line Diagrams/ One Line Diagrams. 15 5 Three Line Diagram. 18 6 Wring Diagram. 21 7 Block Diagrams 24 8 Layout Diagrams 27 3 Classification: Internal Use OBJECTIVES SN OBJECTIVE 1 To understand what are the Electrical diagram and how it’s connected 2 To learn to understand about electrical symbol and abbreviation 3 To understand the wiring and block diagrams 4 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Electrical Diagrams Introduction Electrical diagrams show the components of the circuit (such as lines, symbols, letter and number) as simplified shapes, and the power, signal and control connections between the devices (used to represent electrical circuits). A wiring diagram usually gives information about the relative positions, functions and arrangement of devices and terminals on the devices, to help in followings:  Making new electrical installations.  Locating electrical problems and Troubleshooting.  Modifying existing circuits or Servicing (Testing) of the devices. Sample of Electrical Schematic Note: In some plants, electrical diagrams may also be called prints, or blue prints. 5 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Electrical Diagrams Introduction Drawings and diagrams provide a universally accepted language for communicating information about simple and complex mechanisms, systems, and processes. It is the most efficient way to convey information about systems and equipment from the drafting table to the technician that could not be conveyed by words alone. By the use of symbols and notes, a large amount of information that might require many pages of written description can be presented in a condensed form on one diagram. Sample of Electrical Schematic Note: In some plants, electrical diagrams may also be called prints, or blue prints. 6 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Electrical Diagrams Introduction The use of drawings and diagrams can be of great assistance to the technician when properly used. However, the improper use of these drawings can cause many wasted hours by diverting the technician towards an improper course of action. Many personnel consider print reading a difficult task, but nothing is difficult once the basics are learned. There are many types of electrical prints/diagram/drawings available as below listed:  Single Line Diagrams/ One Line Diagrams.  Schematic Diagrams.  Wiring Diagrams. Sample of Electrical Schematic  Block Diagrams. Note:  Layout Drawing. In some plants, electrical diagrams may also be called prints, or blue prints. 7 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Electrical Diagrams Symbols and Abbreviations The diagrams symbols have been standardized by two different guidelines: American National Standards Institute (ANSI) and the International Electrotechnical Commission (IEC). Each standard is going to have their own versions of a component’s schematic symbol. It is important to follow one of these two standards so that if anyone else comes across a schematic you’ve created, they are able to read it properly. The followings comparison of electrical circuit symbols is based on the international/national specifications (ANSI and IEC Standards): 8 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Note: The above listed symbols are some of international/national specifications/standards but not limited to. 9 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Note: The above listed symbols are some of international/national specifications/standards but not limited to. 10 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Protection Device Function Symbols and Abbreviations (Numbers) There are two methods for indicating protection relay functions in common use.  One is given in ANSI Standard by use a numbering system for various functions.  The other is given in IEC and uses graphical symbols Device function numbers standardized by IEEE and updated from time to time are used in many countries. Each number with its corresponding function name and the general description of each function. Below is the used representing of Restricted Earth Fault Protection with both ANSI and IEC standards: Click on the PDF document to view the details ANSI device numbers. Adobe Acrobat Document ANSI IEC 11 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS 12 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS In General, each of an electrical circuits diagrams developer is showing/listing the used symbols with their designations in legend sheet such as below sample. That to support and clarifying for end-users understanding. 13 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS 14 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Single Line Diagrams/ One Line Diagrams. What is single line or one line diagram ?  Single line diagram gives you a basic understanding of the functions of the components of a system.  The first difference between block diagram and single line diagram is that the single-line diagram uses symbols to represent components.  The single-line diagram is very simplified and should be used primarily to learn the function of each of the various components as a part of the total system.  In power engineering, a one-line diagram or single-line diagram is a simplified notation for representing a three-phase power system.  Electrical elements such as circuit breakers, transformers, capacitors, bus bars, and conductors are shown by standardized schematic symbols.  Instead of representing each of three phases with a separate line or terminal, only one conductor is represented.  It is a form of block diagram graphically depicting the paths for power flow between entities of the system. 15 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Single Line Diagrams/ One Line Diagrams. What is single line or one line diagram ?  Elements on the diagram do not represent the physical size or location of the electrical equipment, but it is a common convention to organize the diagram with the same left-to-right, top-to-bottom sequence as the switchgear or other apparatus represented.  One line diagram shows by means of single lines and graphic symbols, the flow of electrical or the course of electrical circuits and how they are connected. In this diagram, physical relationship are usually disregarded. A typical one line diagram is shown in figure.  A single line diagram shows the disposition of equipment in a substation. In a simplified manner, using internationally accepted symbols to represent various items of substation such as transformers, circuit breakers, disconnectors etc.  Generally with a single line being used to represent three phase connections. Often the main data for the HV equipment is included on the diagram. More detailed single line diagrams include such items as the instrument transformers, and the protection, measurement and control equipment and their associated secondary wiring. 16 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Example of single line diagram. 17 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Three Line Diagram. Purpose  Three-line diagrams help plant maintenance and operations personnel to understand power system operations.  They are also used to develop metering and protective relay wiring drawing. Three line diagram provides detailed information pertaining to three-phase circuitry that is not shown on a one-line diagram. A three-line diagram represents power system components using the same standardized symbols as a one line diagram plus an additional set of standardized symbols that are also used in schematic and wiring diagrams. Unlike one-line diagram, a three-line diagram shows every conductor of a power circuit as an individual line. The schematic diagrams (sometimes called three line or power elementary diagrams) are drawings that show all the components in their proper electrical positions, but not necessarily in their proper physical location. Schematic diagrams are actually expanded and more detailed versions of single line diagrams. 18 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Three Line Diagram. Purpose When the circuit functions are in a definite sequence, they are so arranged on the diagram. Schematic diagrams are typically read from left to right and from top to bottom. Standard electrical symbols and device numbers are used to represent a device or part of a device. The position of contacts, switches, relays, and other devices is shown in the relaxed, non-operated, or de-energized state. That is, the drawing is shown as though there is no power, temperature, pressure, level, etc. Circuit breakers are usually shown in the open position therefore, relays and switches associated with the circuit breaker indicate this condition. All symbols shown on a schematic drawing are labeled. The ampere ratings ,of fuses and circuit breakers, the ohmic value of resistors, and the microfarad values of capacitors are placed below the symbol. Standard device function numbers are used to identify most of the devices found on schematic and one line diagrams. 19 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Adobe Acrobat Adobe Acrobat Document Document Example of Three line diagram. 20 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Wring Diagram.  Wiring diagrams or connections diagrams show the relative position of various components of the equipment and how each conductor is connected in the circuit. These diagrams are classified in two ways: internal wiring diagrams and external wiring diagrams. The internal wiring diagram show the physical arrangement of devices, and accessory items such as terminal blocks, fuse blocks, resistors, relays, etc. The internal wiring diagram usually deals only with the wiring in a particular panel. The external wiring diagram shows the physical arrangement of the panels and all interconnecting wiring and cables.  The wiring diagram is used by the panel or switchgear manufacture to build the panel or the owner for modifications or rewiring. The wiring diagram may be used as a troubleshooting device because it shows the relative position of devices and terminals.  The schematic diagram is used to determine how the circuit functions and what terminal points to use for voltage testing, etc and the wiring diagram is used to find the terminal points in the panel. 21 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Wring Diagram.  Each device in a panel or unit of switchgear assembly, is assigned an arbitrary identification letter or pair of letters. Such letters are also assigned to each terminal block, fuse block, resistor or other accessory device in the panel. The letters can be assigned consecutively from left to right and top to bottom or right to left, top to bottom.  Each stud or terminal point on a device, indicating instrument or meter is assigned a number from left to right, top to bottom or right to left, top to bottom. Again, this number is determined by the manufacturer or owner. Stud numbers should be verified by examining the internal device diagrams on the schematics or wiring diagrams. 22 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Example of wring diagram. 23 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Block Diagrams  Block diagrams are the simplest of all electrical diagrams. A block diagram will illustrate the major components and electrical or mechanical interrelations in block (square, rectangular, or other geometric figure) form. The lines between the blocks represent the connections between the systems or components. Each line may represent one wire or several wires. The purpose of a block diagram is to introduce the system as a whole, conveying the general operation and arrangements of the major components and show the normal order of progression of a signal or current flow. Figure 7-1. is an example of a block diagram.  Block diagrams are commonly used in conjunction with text material explaining the interactions of the major components. When analyzing block diagrams, the components cannot be recognized without the written information that is provided with each block or symbol. Although the actual operation of the system cannot be fully understood without some narrative explanation, the overall concept of the system is presented.  Reading a block diagram is relatively easy. As shown in Figure 7-1, the first component is the 480 volt, 30 60 Hz load center. This is the power supply that provides power to the motor circuit. That is all that is known about the first block. 24 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Block Diagrams  Following the line from the load center, the next component in line is the motor controller which controls the operation of the motor. Also going into the motor controller block is another line from the control devices block. The input from the control devices decides to turn the motor ON or OFF and connects or disconnects the motor from the load center. Assuming the motor is on, power will go from the load center, through the motor controller, and to the motor.  As demonstrated, block diagrams are used to see what parts are included in the system and what electrical order the parts are in. Knowing this, the system can be analyzed to determine where a fault might be. For example, if there is no voltage to the motor, Figure 7-1 can be used to help analyze the problem. If all of the other loads powered by the load center had power, the problem is probably in the motor controller or control devices. If the other loads also did not have power, then the problem would be with the load center.  Block diagrams are useful but have some disadvantages. They do not show the accurate physical location of the components in the system. Also, all electrical connections are represented by a single line. There is usually no indication whether the single line represents a cable or several cables. 25 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Block Diagrams  The block diagram is a useful tool. It is a logical means of first introducing the system as a whole and conveying the general operation and arrangement of major components. After introducing the system overview, the next step is to present the same system, introducing each major component using standard terminology, provide component names and important information, and show the electrical connections of all major components. This is done with a single line diagram. Sample of Block Diagram 26 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Layout Diagrams This sample of substation layout drawing.  Substation layout diagrams provide scale drawings of the location of each piece of equipment in a substation -both in plan and elevation.  Although electrical engineers may not be directly involved with layout diagrams, these drawings do show the relationship between various items of primary equipment and the location of those items associated with protection systems.  The substation layout drawings are required for indoor substations. They shall be showing the substation arrangement including the layout of the equipment and the arrangement of all pits and conduits.  The drawing shall be fully dimensioned and must show HV switchgear, transformer, LV switchboards, protection panels, batteries and battery chargers, communications panels, SCADA equipment, fire extinguishers, equipment storage and drawing holders. The plan must also detail the ventilation arrangement and also the access and egress paths. 27 Classification: Internal Use UNDERSTANDING OF ELECTRICAL DIAGRAMS Adobe Acrobat Document 28 THANK YOU