Commissioning Protective Relay Systems

Engineering Encyclopedia Saudi Aramco DeskTop Standards Commissioning Protective Relay Systems Note: The source of the technical material in this volume is the Professional Engineering Development Program (PEDP) of Engineering Services Warning: The material contained in this document was developed for Saudi Aramco and is intended for the exclusive use of Saudi Aramco’s employees Any material contained in this document which is not already in the public domain may not be copied, reproduced, sold, given, or disclosed to third parties, or otherwise used in whole, or in part, without the written permission of the Vice President, Engineering Services, Saudi Aramco Chapter : Electrical File Reference: EEX30203 For additional information on this subject, contact W.A Roussel on 874-6160 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Content Page INTRODUCTION SAUDI ARAMCO REQUIREMENTS Types Electro-Mechanical Solid State Characteristics EVALUATING PROTECTIVE RELAY SYSTEMS UPON RECEIPT 11 Visual Inspection 11 Verification Against Specifications 12 EVALUATING PROTECTIVE RELAY SYSTEM INSTALLATION AND TESTING .16 Mechanical Checks 16 Electrical Tests .18 Insulation Test 18 Pickup Test 19 Timing Test 20 Miscellaneous Electrical Tests .20 SYSTEM PRE-OPERATIONAL CHECK-OUT 21 PDD Point-to-Point Wiring Check 21 Subsystem Checks 21 WORK AID 1: REFERENCES FOR EVALUATING PROTECTIVE RELAY SYSTEMS UPON RECEIPT 22 Work Aid 1A: Protective Relay System Ratings and Requirements 22 Work Aid 1B: Standard Electrical Symbols and Device Numbers 26 Work Aid 1C: Device Suffix Letters 32 Work Aid 1D: Saudi Aramco Pre-Commissioning Form P-021 Excerpts 35 WORK AID 2: REFERENCES FOR EVALUATING PROTECTIVE RELAY SYSTEM INSTALLATION AND TESTING 38 Saudi Aramco DeskTop Standards Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Work Aid 2A: Procedures and Methods for Evaluating Instrument Transformer and Meter Installation and Testing 38 Mechanical Checks 38 Electrical Tests .39 Work Aid 2B: Saudi Aramco Pre-Commissioning Form P-021 Excerpts 39 GLOSSARY 44 Saudi Aramco DeskTop Standards Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Table of Figures Page Figure 1: Example Induction-Type Relay Figure 2: Basic Electro-Mechanical Relay Circuit Figure 3: Block Diagram of a Solid State Current Relay Figure 4: Protective Relay Time-Current Characteristics Figure 5: Overcurrent Device Coordination 10 Figure 6: Typical Electro-Mechanical Overcurrent Relay 12 Figure 7: Typical Saudi Aramco Bus Overcurrent Protection Scheme 15 Figure 8: Electro-Mechanical Overcurrent Relay That Has Been Removed From Its Case 17 Figure 12: Standard Current and Voltage Ratings for Relays (From ANSI/IEEE C37.90) 22 Figure 13: Saudi Aramco Protective Relay System General Requirements (From SAES-P-114) 23 Figure 13: Saudi Aramco Protective Relay System General Requirements (From SAES-P-114)(Cont'd) 24 Figure 14: Relaying Electrical Symbols 26 Figure 15: NEMA Device Function Numbers 27 Figure 15: NEMA Device Function Numbers (Cont'd) 28 Figure 15: NEMA Device Function Numbers (Cont'd) 29 Figure 15: NEMA Device Function Numbers (Cont'd) 30 Figure 15: NEMA Device Function Numbers (Cont'd) 31 Figure 16: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays 36 Figure 17: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays 37 Figure 18: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays 40 Figure 19: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays 41 Figure 20: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays 42 Figure 21: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays 43 Saudi Aramco DeskTop Standards Engineering Encyclopedia Electrical Commissioning Protective Relay Systems INTRODUCTION Protective relay systems are installed to cause the prompt removal from service of any element of a power system when it suffers a short circuit or when it starts to operate in any abnormal manner that might cause damage or otherwise interfere with the effective operation of the rest of the system Protective relay systems consist of three types of elements that work together to perform the desired protective function: the sensing devices, the protective relays, and the controlling (or isolating) devices The sensing devices (e.g., CT or VT) continuously monitor power systems from generation, through transmission and distribution, to utilization Faults or abnormal conditions are detected through use of the sensing devices The protective relays receive signals from the sensing devices and provide outputs to the controlling devices (e.g., circuit breakers) When faults or abnormal conditions are detected by the sensing devices, rapid corrective action is initiated to isolate the faulted portion of the system Rapid fault isolation provides a high degree of power continuity, reduces potential personnel hazards, and limits equipment damage The correct selection, installation, and inspection of protective relay systems will directly affect the overall safety, accuracy, and performance of electric power generation, transmission, and distribution systems This Module provides information on the following topics that are pertinent to commissioning protective relay systems: • Saudi Aramco Requirements • Evaluating Protective Relay Systems Upon Receipt • Evaluating Protective Relay Systems Installation and Testing • System Pre-Operational Check-Out Saudi Aramco DeskTop Standards Engineering Encyclopedia Electrical Commissioning Protective Relay Systems SAUDI ARAMCO REQUIREMENTS Relaying provides a critical function in electric power system protection Relays are versatile and reliable, and they can perform a wide variety of functions Relays of various kinds can be set to detect abnormal conditions, such as faults, overloads, power swings, frequency changes, and over/undervoltages Through initiation of a trip of the appropriate circuit breakers, relays can isolate and deenergize a zone of protection to minimize the effect of the disturbance or fault on the remainder of the electric power system A zone of protection is an area in a power system that a protection relay is configured to protect The safe and proper operation of Saudi Aramco electrical generation, transmission, and distribution system installation depends on the proper selection and installation of protective relay systems Because the protective relay system functions to isolate faulted portions of the electrical systems to prevent hazards to personnel and damage to equipment, the improper selection or installation of a protective relay system can lead to disastrous or catastrophic results The types and characteristics of protective relay systems are described in Saudi Aramco standards and in the following text A detailed description of protective relay systems is provided in EEX 106 SAES-P-114, 16-SAMSS-513, and ANSI C37 provide specific guidance that pertains to the material requirements for protective relay systems These requirements must be followed when the equipment is specified in initial project design and also when the commissioning process occurs A protective relay gets voltage and/or current information from an external sensing element in the form of current flow This current flow is some small percentage of the parameter that is being sensed The small representative current flow causes the relay operating element (usually a coil) to open or close The relay operating element opens or closes contacts, which actuate a warning signal or which complete the trip circuit of a circuit breaker The relay usually includes some form of visual indicator, which is known as a target, to show that the relay has operated Specific Saudi Aramco protective relay design requirements are provided in Work Aid Types The components that are used to construct the various types of relays are often similar in nature across a wide spectrum of relays; such components can generally be grouped into the electromechanical type and the solid state type Saudi Aramco DeskTop Standards Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Electro-Mechanical Electro-mechanical relays use a combination of electrical fields and mechanical motion An electrical field that is proportional to the measured quantity (e.g., system voltage or current) causes mechanical motion within the electro-mechanical relay Electro-mechanical units can be further subdivided into magnetic attraction units and magnetic induction units A magnetic attraction unit uses instrument transformer secondary outputs (either voltage or current) to create magnetic fields within the relay unit An example of a magnetic attraction unit is a simple plunger relay When the current or voltage magnitude that is applied to the coil exceeds a predetermined value, the magnetic field that is formed will cause a plunger to move upward The action of the moving plunger closes or opens a set of contacts Plunger relays are often used as components in overcurrent relays A magnetic induction unit uses the principle of an induction motor in which torque is developed through use of induction onto a rotor Induction-type relays are only used in ac applications The rotating element of an induction-type relay is usually a disk or a cylinder The two basic designs of a magnetic induction relay are the induction disk and the induction cup A typical induction-disk relay is shown in Figure In Figure 1, the operating torque on the disk is produced through use of an electromagnet that has a main coil and a lag coil The coil terminals receive current from the external sensing element The current from the external sensing element becomes the main coil operating current The lag coil produces a magnetic flux that is out of phase with the main coil The electromagnetic field flows in the laminated core of the relay, across the disk air gap, and through the keeper The combination of the in-phase and out-of-phase magnetic flux across the disk air gap causes torque to be produced on the rotating disk The magnitude and direction of the input quantities determine the speed and direction of the rotating disk, which can be adjusted for a specific timedelay As the disk rotates, trip contacts are opened or closed The three-dimensional view of the disk and the contacts, which is also shown in Figure 1, shows a simplified example of the stationary and movable trip contact operation Saudi Aramco DeskTop Standards Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 1: Example Induction-Type Relay The operational objective of an electro-mechanical relay is to actuate an alarm or to initiate a circuit breaker trip when a power system parameter exceeds a preset value Each relay design achieves its operational objective through a variation of the basic electro-mechanical relay circuit that is shown in Figure The basic electro-mechanical relay circuit receives an input signal from the secondary winding of an instrument transformer The instrument transformer primary winding receives an input signal from the power system The electro-mechanical relay operating element uses the input signal from the secondary winding to produce a magnetic field The electro-mechanical relay operating element compares the force of the produced magnetic field to a known value (e.g., gravity or spring) When the force of the produced magnetic field exceeds the force that is exerted by gravity or by a spring, the relay contacts close and complete the circuit for the output signal The output signal then flows from the power supply for circuit breaker tripping through the circuit breaker trip coil and the alarm This output signal trips the power system circuit breaker and activates an alarm Saudi Aramco DeskTop Standards Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 2: Basic Electro-Mechanical Relay Circuit Electro-mechanical relays can be used as follows: • Overcurrent Relays • Overvoltage Relays • Undervoltage Relays • Undervoltage Frequency • Directional Overcurrent Relays • Directional Power Relays • Differential Relays • Distance Relays • Phase Balance Current Relay • Loss of Excitation Relays • Lockout Relays • Synchronism Relays Saudi Aramco DeskTop Standards Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Solid State Solid state relays are electronics-based units that perform the same function as the electromechanical units; however, solid state circuits replace the moveable elements of a relay In solid state relays, electronic logic circuits are used to determine whether the direction and magnitude of the input values are sufficient to require protective action Although solid state and electromechanical relays use different methods to initiate protective action at pre-determined levels, they accomplish the same results Solid state devices are available for use as individual protective relays or as a protection package A protection package is a group of individual protective relays that have been combined into a single unit All electro-mechanical devices are available in solid state versions Although the solid state devices are different in construction and operation, the solid state devices can perform the same functions and can be applied in the same manner as the electro-mechanical devices Figure shows a block diagram of a typical solid state current relay The function of this relay is to provide instantaneous and time overcurrent protection for a load The current flow to the load is sensed through use of the main current transformer The main current transformer transmits this current signal to the auxiliary transformer The current flow through the auxiliary current transformer develops a voltage signal across the secondary resistor The voltage across the secondary resistor will be proportional to the original current flow through the main current transformer The voltage signal provides the input signal to the inverse time circuit and the instantaneous circuit of the solid state relay The inverse time circuit consists of a rectifier, a solid state switch, a solid state timer, a trigger, and a memory coil The ac input voltage that is proportional to the line current is converted to dc through use of diodes in the rectifier of the inverse time circuit The dc output from the rectifier provides an input signal to the solid state switch When the input signal exceeds a preset value, the solid state switch starts to conduct and provides an output signal to the solid state timer The input signal to the solid state timer starts to charge a capacitor in the solid state timer The capacitor charging time varies with the magnitude of the original input signal When the capacitor is fully charged, the trigger circuit emits a pulse through the memory coil, which actuates the trip unit The trip unit trips the circuit breaker to isolate power to the load The instantaneous circuit consists of a breakdown diode, a solid state switch, and a memory coil The breakdown diode starts to conduct when the input voltage exceeds a preset value The preset value is determined through the construction of the diode When the diode conducts, the breakdown diode converts the input ac voltage to a dc output voltage The dc output voltage provides an input to the solid state switch When the breakdown diode conducts, the solid state switch emits a pulse through the memory coil, which actuates the trip unit The trip unit trips the circuit breaker to isolate power to the load Saudi Aramco DeskTop Standards Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Number 74 Name Alarm Relay Function The alarm relay is a relay (other than an annunciator as covered under device function 30) that is used to operate, or to operate in connection with, a visual or audible alarm 76 Dc Overcurrent Relay The dc overcurrent relay is a relay that functions when the current in a dc circuit exceeds a given value 78 Phase-Angle Measuring Relay The phase-angle measuring relay is a relay that functions at a predetermined phase angle between two voltages or between two currents or between voltage and current 79 Ac Reclosing Relay The ac reclosing relay is a relay that controls the automatic reclosing and locking out of an ac circuit interrupter 81 Frequency Relay The frequency relay (also called "Overfrequency or Underfrequency Relay") is a relay that responds to the frequency of an electrical quantity, operating when the frequency or rate of change of frequency exceeds (or is less than) a predetermined value 82 Dc Reclosing Relay The dc reclosing relay is a relay that controls the automatic closing and reclosing of a dc circuit interrupter, generally in response to load circuit conditions 83 Automatic Selective Control Relay The automatic selective control or transfer relay is a relay that operates to select automatically between certain sources or conditions in an equipment, or to perform a transfer operation automatically 85 Carrier or Pilot-Wire Receiver Relay The carrier or pilot-wire receiver relay is a relay that is operated or restrained by a signal that is used in connection with carrier-current or dc pilot-wire fault relaying 86 Lockout Relay The lockout relay is a hand or electrically reset auxiliary relay that is operated by tripping of another protective relay upon the occurrence of abnormal conditions to maintain associated equipment or devices inoperative until that are reset Figure 15: NEMA Device Function Numbers (Cont'd) Saudi Aramco DeskTop Standards 30 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Number 87 Name Differential Protective Relay Function The differential protective relay is a protective relay that functions on a percentage, phase angle, or other quantitative difference between two electrical quantities 91 Voltage Directional Relay The voltage directional relay is a relay that operates when the voltage across an open circuit breaker or contactor exceeds a given value in a given direction 92 Voltage and Power Directional Relay The voltage and power directional relay is a relay that permits or causes the connection of two circuits when the voltage difference between them exceeds a given value in a predetermined direction The voltage and power directional relay causes these two circuits to be disconnected from each other when the power flowing between them exceeds a given value in the opposite direction 94 Tripping or Trip-Free Relay The tripping or trip-free relay is a relay that functions to trip a circuit breaker, contactor, or equipment, or to permit immediate tripping by other devices; or to prevent immediate reclosure of a circuit interrupter if it should open automatically even though its closing circuit is maintained closed Figure 15: NEMA Device Function Numbers (Cont'd) Saudi Aramco DeskTop Standards 31 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Work Aid 1C: Device Suffix Letters Suffix letters are used with device function numbers to further indicate the exact function of a particular piece of equipment A complete listing and a detailed explanation of suffixes are contained in ANSI Standard Y1.1-1972, "Abbreviations for Use on Drawings and in Text." This section of the Work Aid contains lists of the suffixes that are most often used in Saudi Aramco drawings and prints The following letters indicate the condition or electrical quantity to which the device responds or the medium in which it is located • A Air or Amperes • C Current • E Electrolyte • F Frequency or Flow • L Level or Liquid • P Power or Pressure • PF Power Factor • Q Oil • S Speed • T Temperature • V Voltage, Volts, or Vacuum • VAR Reactive Power • W Water or Watts Saudi Aramco DeskTop Standards 32 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems The following letters denote the main device in the circuit or the type of circuit (BL for blocking circuit) to which the numbered device is applied or related • A Alarm or Auxiliary Power • AN Anode • B Battery, Blower, or Bus • BK Brake • BP Bypass • BT Bus Tie • C Capacitor, Condenser, Compensator or Carrier Current • CA Cathode • DC Direct Current • E Exciter • F Feeder, Field or Filament • G Generator or Ground ** • H Heater or Housing • L Line • M Motor or Metering • MOC Mechanism Operated Contact (circuit breaker mechanism operated cell switch) • N Network or Neutral ** • P Pump • R Reactor or Rectifier • S Synchronizing • T Transformer, Test or Thyratron • THE Transformer (High-Voltage Side) • TL Transformer (Low-Voltage Side) • TM Telemeter • U Unit Saudi Aramco DeskTop Standards 33 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems ** Suffix "N" is generally used in preference to "G" for devices connected in the residual connection of current transformers ** Suffix "G" is more commonly used for those relays which are connected to a current transformer whose primary winding is located in the neutral of a machine or power transformer, and in the case of transmission line relaying, which operates on ground-faults The following is a list of miscellaneous suffix letters that are used in Saudi Aramco drawings and prints • A Accelerating or Automatic • B Blocking or Backup • C Close or Cold • D Decelerating, Detonate, or Down • E Emergency • F Failure or Forward • H Hot or High • HR Hand Reset • HS High Speed • L Left or Local or Low or Lower or Leading • M Manual • OFF Off • ON On • O Open • P Polarizing • R Right or Raise or Reclosing or Receiving or Remote or Reverse • S Sending or Swing • T Test or Trip or Trailing • TDC Time-Delay Closing • TDO Time-Delay Opening • U Up Saudi Aramco DeskTop Standards 34 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Work Aid 1D: Saudi Aramco Pre-Commissioning Form P-021 Excerpts Figures 16 and 17 show sheets and (of 12) from the Saudi Aramco Pre-Commissioning form, P-021, Protective Relays Sheet is used to evaluate protective relay systems upon receipt, and sheet contains a checklist for specific relay or instrument visual and mechanical inspections For protective relay systems that contain more than five instruments or relays, multiple copies of sheet may be used Saudi Aramco DeskTop Standards 35 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 16: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays Saudi Aramco DeskTop Standards 36 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 17: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays Saudi Aramco DeskTop Standards 37 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems WORK AID 2: REFERENCES FOR EVALUATING PROTECTIVE RELAY SYSTEM INSTALLATION AND TESTING Work Aid 2A: Procedures and Methods for Evaluating Instrument Transformer and Meter Installation and Testing The procedures and methods for evaluating protective relaying system installation and testing are divided into the following categories: • Mechanical Checks • Electrical Tests Mechanical Checks The mechanical checks of protective relays should be performed in accordance with the manufacturer's technical manuals that are provided with the protective relays The specific mechanical checks are provided in the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays All mechanical check data must be entered in the appropriate section of P-021 The general procedure for performing a mechanical check of an electro-mechanical protective relay during the commissioning process is as follows: Any rust or filings must be removed from the disk and magnetic poles with a magnet cleaner or brush Check the relay for friction The relay disk must not be warped or bent The relay disk must have proper clearance between the disk and the magnet poles The disk rotation must be checked by hand The disk should move freely and reset smoothly Relay contacts must be clean and tight If auxiliary target devices, plunger relays, or annunciator coils are present, they must be checked for friction and freedom of moving parts Solid state protective relays have no moving parts, so the mechanical checks that are performed on solid state relays during the commissioning process are limited to checking for the correct installation and any indication of damage Saudi Aramco DeskTop Standards 38 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Electrical Tests The electrical tests of protective relays should be performed in accordance with the manufacturer's technical manuals that are provided with the protective relays The specific electrical tests are provided in the associated section of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays Work Aid 2B: Saudi Aramco Pre-Commissioning Form P-021 Excerpts Figures 18 through 21 contain a representative portion of Saudi Aramco Pre-Commissioning Form P-021, Protective Relays from GI-2.710 Saudi Aramco DeskTop Standards 39 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 18: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays Saudi Aramco DeskTop Standards 40 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 19: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays Saudi Aramco DeskTop Standards 41 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 20: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays Saudi Aramco DeskTop Standards 42 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 21: Sheet (of 12) of the Saudi Aramco Pre-Commissioning Form, P-021, Protective Relays Saudi Aramco DeskTop Standards 43 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems GLOSSARY backup protection a form of protection that consists of protective devices that operate independently of specified components in the primary protective system and that is intended to operate if the primary protective device or apparatus fails or is out of service circuit element a basic part of the circuit in question, e.g., conductors, interrupting devices, transformers, etc current transformer An instrument transformer that is intended to have its primary winding connected in series with the conductor that carries the current to be measured or controlled fault a partial or total local failure in the insulation or continuity of a conductor instrument transformer A transformer that is intended to reproduce in this secondary circuit, in a definite and known proportion, the current or voltage of its primary circuit with the phase relations substantially preserved line side the supply side of a circuit element from which the circuit element receives its source of voltage This is also known as the "upstream side" of a circuit element load side the side of a circuit element from which the voltage is supplied to the load This is also known as the "downstream side" of a circuit element overlapping zones of protection the distance that one relay's reach extends into the zone of protection of another relay, generally to provide comprehensive protection of components, such as circuit breakers protective zone the zone that lies between two or several sets of current transformers that, together with the relays, constitute the protective system for that portion of the power system reach the maximum distance from the relay sensing device (CT or VT) location to a point of overcurrent for which a particular relay will operate Saudi Aramco DeskTop Standards 44 [...]... Electrical Commissioning Protective Relay Systems Figure 3: Block Diagram of a Solid State Current Relay Solid state relays can be used as follows: • • • • • • Overcurrent Relays Overvoltage Relays Undervoltage Relays Underfrequency Relays Directional Overcurrent Relays Directional Power Relays • • • • • • Differential Relays Distance Relays Phase Balance, Voltage, and Current Relays Loss of Excitation Relays... operational acceptance of each protective relay in the system and must be conducted prior to commissioning and release of the protective relay system for operation Saudi Aramco DeskTop Standards 21 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems WORK AID 1: REFERENCES FOR EVALUATING PROTECTIVE RELAY SYSTEMS UPON RECEIPT Work Aid 1A: Protective Relay System Ratings and Requirements... DeskTop Standards 14 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 7: Typical Saudi Aramco Bus Overcurrent Protection Scheme Saudi Aramco DeskTop Standards 15 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems EVALUATING PROTECTIVE RELAY SYSTEM INSTALLATION AND TESTING After protective relay systems have been installed and prior to the equipment... Aramco DeskTop Standards 10 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems EVALUATING PROTECTIVE RELAY SYSTEMS UPON RECEIPT When protective relays are received as a part of the total inventory of equipment for a protective relay system installation, a receipt inspection must be performed to ensure that the protective relays are of the proper type as specified in the installation... Encyclopedia Electrical Commissioning Protective Relay Systems A detailed mechanical inspection procedure is provided in Work Aid 2 Mechanical inspection checks are provided on sheets 1 and 3 of the Saudi Aramco Pre -Commissioning Form P-021, Protective Relays A representative portion of Saudi Aramco Pre -Commissioning Form P-021, Protective Relays, is provided in Work Aid 2 Solid state protective relays have no... Standards 25 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Work Aid 1B: Standard Electrical Symbols and Device Numbers Figure 14 shows standard electrical symbols for protective relaying systems Figure 14: Relaying Electrical Symbols Saudi Aramco DeskTop Standards 26 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 15 shows NEMA device function... verifying protective relay systems against the specifications during the commissioning process is to ensure that the equipment that is being installed meets Saudi Aramco and industry standards Minimum design package and general requirements for protective relay systems are provided in Work Aid 1 Saudi Aramco DeskTop Standards 12 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems. .. present in the protective relay When the pickup tests are performed, a check should also be made to ensure that the proper relay position indicators function Saudi Aramco DeskTop Standards 19 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Timing Test With protective relays, not only must the relay pick up at a predetermined value of sensed current, but the relay operation... Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Number 47 Name Phase-Sequence Voltage Relay Function The phase-sequence voltage relay (also called "Negative Phase-Sequence Voltage Relay" ) is a relay that functions at a predetermined value of polyphase voltage in the desired phase sequence 48 Incomplete Sequence Relay The incomplete sequence relay is a relay that returns the equipment... faults Saudi Aramco DeskTop Standards 8 Engineering Encyclopedia Electrical Commissioning Protective Relay Systems Figure 4: Protective Relay Time-Current Characteristics The time-delay overcurrent device is used to coordinate with other protective devices or relays The time before the trip signal is sent from the protective relay to the breaker varies inversely to the magnitude of the fault current ... Electrical Commissioning Protective Relay Systems EVALUATING PROTECTIVE RELAY SYSTEMS UPON RECEIPT When protective relays are received as a part of the total inventory of equipment for a protective relay. .. that are pertinent to commissioning protective relay systems: • Saudi Aramco Requirements • Evaluating Protective Relay Systems Upon Receipt • Evaluating Protective Relay Systems Installation... Encyclopedia Electrical Commissioning Protective Relay Systems Number 87 Name Differential Protective Relay Function The differential protective relay is a protective relay that functions on