Introduction To Power System Protection & Relays
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P. GOPALA KRISHNA ADE/400KV/APTRANSCO
Power Systems Protection -Introduction
Power Systems Protection -Introduction
Power Evacuation Substation Transmission Substation Switching Substation Distribution Substation
Power Systems Protection -Introduction
Power System Components 1. Generators 2. Transformers 3. Transmission Lines 4. Feeders 5. Motors 6. Capacitor Banks 7. Bus Bars 8. Reactors
Power Systems Protection -Introduction
Why we need the Protection ? ¾ To detect abnormalities (faults). ¾ To eliminate such abnormality by isolating smallest portion of the system in a shortest period of time. ¾ To prevent injury to personnel. ¾ To prevent damage to Equipment. ¾ Enable
Continuous
service
undamaged part of the network.
in
Power Systems Protection -Introduction
Protective Relay – What should it do ? ¾ Monitor system parameters continuously (V, I, P, F) ¾ Operate quickly when necessary (Dependability) ¾ Should not operate wrongly (stability, discrimination)
To trip or not to trip ?
Power Systems Protection -Introduction
Protective System – What are the Requirements? ¾ Speed The relay must operate at the required speed. It should neither be too slow which may result in damage to the equipment nor should it be too fast which may result in undesired operation. Damage can be Minimised.
¾ Sensitivity The relaying equipment must be sufficiently sensitive so that it operates reliably when required under the actual conditions that produces least operating tendency and to detect all possible Shunt and series Faults.
¾ Selectivity The relay must be able to discriminate (select) between those conditions for which prompt operation is required and those for which no operation, or time delayed operation is required. Isolate only Faulty Section without disturbing Healthy Section.
¾ Reliability The most important requisite of protective relay is reliability since they supervise the circuit for a long time before a fault occurs; if a fault then occurs, the relays must respond instantly and correctly. The Operation Capability of the Protection System is summerised in “ reliability”, which includes both the security in fault clearance and the security against undesired clearances. The security in fault clearance is called dependability and the security against undesired clearances is called Security.
Power Systems Protection -Introduction
Protective Relay Scheme – What is it ? ¾ ¾ ¾ ¾ ¾ ¾ ¾
A Protective Relay CT / CVT / PT(EMVT) Auxiliary Power Supply (24 V to 240 V AC/ DC) Switching Device ( Breaker/ Isolator / Contactor) Trip Coil Alarm / Trip contact Control Wiring
Power Systems Protection -Introduction
Power System - Faults Current Over Load Over Current Earth Fault Current Unbalance Dir. Over Current Dir. Earth Fault Power Active power Reactive power Over power Under power Reverse power
Voltage Over Voltage Under Voltage Voltage Unbalance Neutral shift Computed Over fluxing Loss of field Differential Over Current Restricted E/F Under Impedance
Frequency Over Frequency Under Frequency dF/dT Control/Management Synchronising Load sharing Islanding Load shedding
DC Relays
Power Systems Protection -Introduction
Protection – ANSI Codes
Code numbers Used to denote Protections On a SLD
Power Systems Protection -Introduction
Power System – Fault Handling
Trip & Isolate Breaker is tripped on fault Faulty section is isolated
Control & Regulate Breaker is not tripped Corrective actions Generated on line
Power Systems Protection -Introduction
Relay operation when a fault occurs ¾ Each Relay should Protect a specific Zone in the System. ¾ If fault is inside its Zone, Relay should operate and isolate the faulted Zone. ¾ If fault is outside zone, Relay should not operate, Some other Relay should operate and isolate
Power Systems Protection -Introduction
What happens when a fault occurs ¾ Fault current flows through number of Relays. ¾ Some of operate.
these
Relays
will
start
to
¾ Only one Relay related to particular fault should trip and interrupt the fault current. ¾ Remaining Relays will reset after above.
Power Systems Protection -Introduction
Protection Relays – Inputs / Out puts Inputs Current Voltage Frequency Power
CTs PTs PTs CTs + PTs
Outputs Trip Contact
Power Systems Protection -Introduction
Protection Relays – Settings Pick up setting
Low set Highset
Time delay setting
Definite time Inverse time
% of CT Rating
TMS Setting
Power Systems Protection -Introduction
Power System – Trip time characteristics
t
1.3 or 3.0 sec
1.4 LS
10
I/Is
Power Systems Protection -Introduction
Power System – Trip time characteristics
t
1.3 or 3.0 sec
50 msec
1.4 LS
6 HS
10
I/Is
Power Systems Protection -Introduction
Typical Inverse Time Delays TIME MULTIPLIER SETTING – TMS : 1.00 I/Is=2 I/Is=4 I/Is=6 I/Is=8 I/Is=10 I/Is=15 I/Is=20 Normal Inv 3 sec
10.13
5.03
3.87
3.33
3.00
2.54
2.29
Normal Inv 1.3 sec
04.39
2.18
1.68
1.44
1.30
1.10
0.99
Very Inverse 1.5 sec
13.50
4.50
2.70
1.93
1.50
0.96
0.71
Extremely Inverse
26.66
5.33
2.28
1.27
0.81
0.36
0.20
Power Systems Protection -Introduction
Things you should know Application SLD representation Front panel Controls Back Panel terminations Inputs / Outputs / Ratings Settings (Inside) Settings (on front panel) Installation & wiring Commissioning Testing (Front panel) Testing (SCITS) Cat . No.
EVALUATION OF PROTECTIVE RELAYS PREPARED BY GOPALA KRISHNA PALEPU ADE/MRT(PROTECTION)
1 ST GENERATION FIRST GENERATION RELAYS : THESE ARE ELECTRO MAGNETIC RELAYS IN THIS NO OF ELECTROMAGNETIC RELAYS PROVIDED FOR ARRIVING A SPECIFIC FUNCTION i.e EACH FUNCTION OF THE SCHEME HAVING A SEPARATE RELAY. COMBINING ALL IS CALLED ONE PROTECTION FUNCTION. NO OF RELAYS ARE MORE AND SPACE OCUPATION IS MORE AND INTER CONNECTION WIRING DIAGRAM IS MORE. DISADVANTAGES: ELECTROMECHANICAL RELAYS HAVE A LOT OF MECHANICAL PARTS, WHICH MAY BECOME CLOGGED WITH DIRT OR CORRODED DUE TO ENVIRONMENTAL CONDITIONS, AFFECTING BOTH OPERATION, CALIBRATION AND MOVEMENT OF THE DISKS. IT REQUIRES PERIODICAL MAINTANENCE AND ADJUSTMENT.
1 ST GENERATION NEXT MODIFICATION : ELECTRO MAGNETIC RELAYS WITH STATIC COMPONENTS IN THIS SOME OF THE FUNCTIONS ARE DERIVED FROM STATIC COMPONENTS PROVIDED ON THE PCB. IN THIS QUANTITY OF ELECTROMAGNETIC RELAYS ARE REDUCED. COMBINING ALL IS CALLED ONE PROTECTION FUNCTION. QUANTITY OF RELAYS ARE REDUCED AND SPACE OCUPATION IS REDUCED SOME WHAT. DISADVANTAGES: THE PCBs ARE MADE WITH TRANSISTORS AND ARE BROUGHTOUT ITEMS WITH DIFFERENT MAKE. AFTER SOME TIME THESE ARE TO BE REPLACED FOR CORRECT OPERATION WITHOUT DRIFT. THE PCBs & COMPONENTS PERFORMANCE MAY BE AFFECTED DUE TO DIST & DIRT. IT REQUIRES PERIODICAL MAINTANENCE AND ADJUSTMENT.
2 ND GENERATION SECOND GENERATION RELAYS : STATIC RELAYS WITH TRANSISTORS In this all of the functions are derived from static components provided on the PCB. In this initially each function is derived with separate static relay. Quantity of static relays are more but space occupation is less. Combining all is called one protection function. Inter connection wiring diagram is still not reduced. DISADVANTAGES: Static relays generally employ a lot of electronic components made by other manufacturers. If these electronic components are not tested with rigorous quality control, the chances of failure of components during the relay life time may exist. A reliable DC power source within the relay, to electronically measure circuits has to be generated from available external power sources. Most of the static relays employ series, shunt, or switched mode power supply designs. For a variety of reasons, if these power supplies fail, the measuring circuits are inoperative and the relay is dead for any measurements. No protection is available to the network. Most of the static relays in use do not have the means to detect the failure of power supply and initiate an alarm. It requires periodical Maintenance.
2 ND GENERATION NEXT MODIFICATION : STATIC RELAYS ON SINGLE PCB IN THIS ALL OF THE FUNCTIONS ARE DERIVED FROM STATIC COMPONENTS PROVIDED ON THE PCB. IN THIS ALL STATIC RELAYS ARE TAKEN TO ONE MASTER PCB AND EACH FUNCTION PCB WILL BE ADD ON CARD TYPE. SO TOTAL RELAY IS ONE BUT FOR EVERY FUNCTION IS PCB IS AVAILABLE AND CONNECTED TO MAIN PCB. SPACE OCCUPATION IS LESS. COMBINING ALL IS CALLED ONE PROTECTION FUNCTION. NO INTER CONECTION WIRING. THIS IS PART OF MAIN PCB. DISADVANTAGES: DISADVANTAGES ARE SAME AS ABOVE.
3 ND GENERATION THIRD GENERATION RELAYS : STATIC RELAYS WITH ICs IN THIS NO OF COMPONENTS ARE REDUCED AND BROUGHT OR BUILT IN ONE INTEGRATED CHIP. DUE TO THIS THE RELAY SIZE IS REDUCED AND SOME OF THE FUNCTIONS ALSO TAKEN IN TO ONE INTEGRATED CHIP. THIS ALSO BUILT IN ONE PCB. ALL OF THE FUNCTIONS ARE DERIVED FROM STATIC COMPONENTS PROVIDED ON THE PCB. IN THIS ONLY MASTER PCB IS AVAILABLE, NO SEPARATE PCB FOR EACH FUNCTION , ALL ARE INTEGRATED IN ONE PCB. PROBLEMS ARE SOME WHAT REDUCED. SPACE OCCUPATION IS LESS. ONE PROTECTION FUNCTION ONLY ONE RELAY AND ALL FUNCTIONS ARE INTEGRATED. NO INTER CONNECTION WIRING DIAGRAM.
3 ND GENERATION NEXT MODIFICATION : SEMI NUMERIC RELAYS IN THIS SOME FUNCTIONS ARE CAN BE PROGRAMMABLE AND INTERFACE THROUGH PC. SOME ICs ARE HAVING THE FACILITY TO INTERACT THROUGH COMMUNICATION PORT. IT IS SOME WHAT MODIFICATION TO IC BASED RELAYS. IN THIS SOME FUNCTION CAN BE ENABLED AND DISABLED, BASED ON THE REQUIREMENT.
4 ND GENERATION MICROPROCESSOR BASED NUMERICAL RELAYS ¾ IN THIS ALL OF THE FUNCTIONS ARE BROUGHT ON ONE IC. THE FOURTH GENERATION PROCESSORBASED RELAYS, DO HAVE THE WATCHDOG FEATURE, WHICH FACILITATES THE CHECKING OF POWER SUPPLY FAILS, CLOCK FREQUENCIES, AND OTHER PATTERNS. MOST OF THESE RELAYS HAVE AUTO TEST FEATURES WHICH TEST THE ELECTRONIC CIRCUIT FUNCTIONS AT REGULAR INTERVALS & AUTOMATICALLY.
MICROPROCESSOR BASED RELAYS ¾ BACK GROUND WORK ¾ ADVANTAGES & DISADVANTAGES ¾ OPERATIONS & ALGORITHMS IN MICROPROCESSOR ¾ FUNCTIONAL BLOCKS & OTHER HARDWARE OF MICROPROCESSOR BASED RELAY ¾ FILTERING TECHNIQUES ¾ TESTING OF MICROPROCESSOR RELAYS
MICROPROCESSOR BASED RELAYS - BACKGROUND WORK
1960s ¾ A FEW CONCEPTS WERE PROPOSED ¾ HARDWARE WAS VERY EXPENSIVE ¾ BENEFITS OF MICROPROCESSORS FOR RELAYS WERE NOT CLEAR ¾ IEEE ARTICLE “FAULT PROTECTION WITH A DIGITAL COMPUTER” OUTLINED THE FEASIBILITY & PROBLEMS ASSOCIATED IN S/S PROTECTION WHEN A DIGITAL COMPUTER IS USED.
MICROPROCESSOR BASED RELAYS - BACKGROUND WORK
1970s ¾
TWO PAPERS WERE PUBLISHED “DIGITAL CALCULATION OF IMPEDANCE FOR TRANSMISSION LINE PROTECTION” “ 3 PH TRANSMISSION LINE PROTECTION WITH A DIGITAL COMPUTER”
¾
PROMINENT MANUFACTURERS LIKE WESTINGHOUSE, IBM STARTED INVESTIGATING S/S COMPUTER SYSTEMS
¾
PHILADELPHIA ELECTRIC & GE INITIATED PROJECTS ON DIGITAL TECHNIQUES FOR PROTECTION
¾
VARIOUS ALGORITHMS WERE DERIVED FOR DIGITAL CALCULATION OF PROTECTION PARAMETRS
¾
EXPERIMENTAL SYSTEMS WERE BUILT BY GE & WESTINGHOUSE TO CHECK ALGORITHMS
¾
FIRST GENERATION OF MICROPROCESSOR BASED RELAYS BUILT
MICROPROCESSOR BASED RELAYS - BACKGROUND WORK 1980s ¾
MAJOR MANUFACTURERS LIKE ABB, GE, GEC , TOSHIBA, SIEMENS START DESIGN & SALES OF BROAD RANGE OF PRODUCTS FOR POWER SYSTEM PROTECTION
¾
MICROPROCESSOR IMPROVES PERFORMANCE SPECS FOR OPERATION IN INDUSTRIAL ENVIRONMENT
¾
MANY PLC BASED SYSTEMS ARE COMMISSIONED IN INDIA BY L&T, SIEMENS, ECIL ETC.
¾
MANY ELECTRICITY BOARDS & PROCESS PLANTS IN INDIA START USING MICROPROCESSOR BASED INSTRUMENTS
¾
THE WORD SCADA GETS POPULAR IN INDIA
¾
PGCIL GOES IN FOR MICROPROCESSOR BASED DISTANCE RELAYS IN INDIA
MICROPROCESSOR BASED RELAYS - BACKGROUND WORK 1990s ¾
ABB & GEC ALSTOM MICROPROCESSOR BASED PROTECTIONS
¾
MAJOR MANUFACTURERS LIKE ABB, GE, GEC , TOSHIBA STARTS DESIGN & SALES OF BROAD RANGE OF PRODUCTS FOR POWER SYSTEM PROTECTION
¾
MANY ELECTRICITY BOARDS & PROCESS PLANTS IN INDIA START USING MICROPROCESSOR BASED INSTRUMENTS
¾
PGCIL GOES IN FOR MICROPROCESSOR BASED DISTANCE RELAYS IN INDIA
¾
MICROCONTROLLERS / DSPs ARE INTRODUCED IN LATE 90s BY HARDWARE MANUFACTURERS WHICH HAVE IMPROVED THE SPEED OF OPERATION.
INTRODUCED RANGE OF RELAYS FOR ALL UNIT
ADVANTAGES OF NUMERIC RELAYS PARAMETER
NUMERIC
CONVENTIONAL
ACCURACY BURDEN SETTING RANGES MULTI FUNCTIONALITY SIZE FIELD PROGRAMMABILITY PARAMETER DISPLAY SYSTEM FLEXILBILITY CO-ORDINATION TOOLS COMMUNICATION REMOTE CONTROL SPECIAL ALGORITHMS SPECIAL PROTECTIONS SELF DIAGNOSTICS
1% < 0.5 VA WIDE YES SMALL YES YES YES MANY YES YES MANY YES YES
5% / 7.5% > 5 VA LIMITED NO LARGE NO NO NO TWO NO NO LIMITED NO NO
DIS-ADVANTAGES OF NUMERIC RELAYS
SOFTWARE INTENSIVE OBSOLESENCE RATE EMI / EMC PROBLEMS SERIAL NATURE
PROTECTION ALGORITHM
MEASUREMENMT METHOD TRIP TIME CALCULATION GOOD FILTERING CHARACTERISTIC (HARMONICS, NOISE, DC SHIFT) FAST TRIP DECISION
FUNCTIONAL BLOCKS OF A NUMERIC RELAY
ANALOG INPUT SU-SYSTEM
RAM
D S P MICRO PROCESSOR
DIGITAL INPUT SUB-SYSTEM
POWER SUPPLY
ROM EPROM FLASH
DIGITAL OUTPUT SUB-SYSTEM
COMMUNICATION INTERFACE
ANALOG INPUT SUB SYSTEM
CT
SURGE SUPPRESSION
ANALOG FILTER MUX
PT
SURGE SUPPRESSION
ANALOG FILTER
A/D CONVERTER
MICRO PROCESSOR
MICROPROCESSORS Vs MICRO CONTROLERS Microprocessor
Micro controller Address Register
Address Register C O N T R O L
Data Register Arithmetic Logic Unit Accumulator
C O N T R O L
Data Register Arithmetic Logic Unit Accumulator
ROM Timers I/O RAM Counters EPROM UART
RELAY HARDWARE 16 / 32 BIT
PC MODEM
IRIG-B RE/CC
NORMALLY 400KV RELAYS SUPPLIED WITH CONFIGUARATION/HARDWARE 1. MIN 4Nos MAX 8Nos COMMAND/TRIP OUTPUTS 2. MIN 24Nos SIGNAL OUTPUTS 3. MIN 14 LED INDICATIONS 4. MIN 24 BINARY INPUTS
FOLLOWING
SELF DIAGNOSTICS - TECHNIQUES USED RAM
Checked by computing a checksum of memory contents and comparing it against a stored factory value.
RAM
Checked by periodically writing a specific data and reading back the memory contents
A/D
Checked by inputing a known value of + / - voltage. Any off set at a given time, is software corrected.
SETTINGS
Checked by checksums or CRC values can be stored and compared. Often, 2 or 3 copies of settings are stored and compared.
POWER SUPPLY
Checked by monitoring power supply voltage values from A / D converter.
TYPES OF SIGNALS REQUIRED FOR PROPER PROTECTION
Current, Voltage and Distance Relays : Require fundamental frequency component signals. All other signals will interfere with protection process.
Harmonic Restraint Relays : Require both the fundamental & the Harmonic components , each value separately, for decision making process.
4 ND GENERATION ¾ 1ST DEVELOPMENT: SOFTWARE DEVELOPMENT IS APPLICATION BASED RELAYS i.e EACH PROTECTION FUNCTION HAVING SEPARATE SOFTWARE & HARDWARE. ¾ Example: 1. LINE PROTECTION, 2. TRANSFORMER PROTECTION, 3. BUSBAR PROTECTION, 4. GENERATOR PROTECTION 5. MOTOR PROTECTION 6. REACTOR PROTECTION 7. CAPACITOR PROTECTION
4 ND GENERATION ¾ 2ND DEVELOPMENT: SOFTWARE DEVELOPMENT IS SOME GROUP BASED RELAYS i.e SOME PROTECTION FUNCTIONS ARE TAKEN IN TO ONE FLATFORM AND PROVIDED COMMON SOFTWARE. FROM THIS INBUILT FACILITY OF EVENT RECORDER AND DISTURBANCE RECORDER IS DEVELOPED. ¾ Example: ABB: 1. REX 5xx SERIES FLATFORM 2. REX 316 SERIES FLATFORM 3. REX 670 SERIES FLATFORM 4. RED 500 SERIES FLATFORM 5. RED 600 SERIES FLATFORM
4 ND GENERATION ¾ 3RD DEVELOPMENT: UNIVERSAL SOFTWARE FOR ALL TYPES OF RELAYS FOR PARTICULAR MANUFACTURER. i.e. ONE SOFTWARE ONE MANUFACTURER. ¾ Example: 1. SIEMENS: SIPROTEC SERIES – DIGSI 2. GE MULTILIN: ENERVISTA 3. AREVA : MICOM S1
4 ND GENERATION ¾ 4TH DEVELOPMENT: UNIVERSAL HARDWARE FOR ALL TYPES OF RELAYS FOR PARTICULAR MANUFACTURER. ONE HARDWARE FOR ONE MANUFACTURER. BUT IT IS MODULAR DESIGN. RELAY IS COMMON HARDWARE BASED ON PROTECTION FUNCTION, PARTICULAR CARD IS ADDED. ¾ Example: 1. GE MULTILIN: UR SERIES & SR SERIES
4 ND GENERATION ¾ 5TH DEVELOPMENT: EACH MANUFACTURER ADOPTING THEIR PROPERITIERY BASED PROTOCOL FOR COMMUNICATION, INTERFACING, NETWORKING AND AUTOMATION. SOME UTILTIES ARE REQUESTED MANUFACTURERS TO SUIT THEIR ADOPTED PROTOCOL. ¾ Example: 1. UCA – Utility communication architecture 2. LON 3. SPA 4. PROFIBUS 5. MODBUS 6. DNP 7. FIELDBUS 8. MVB 9. IEC 60870
4 ND GENERATION ¾ 6TH DEVELOPMENT: BASED ON THE EXPERIENCE WITH DIFFERENT PROTOCOLS, NEED FOR UNIFORMITY AND KNOW – HOW FOR GLOBAL CONSIDERATION ONE WORLD ONE TECHNOLOGY ONE STANDARD A UNIVERSAL PROTOCOL FOR COMMUNICATION, INTERFACING AND NETWORKING IS DEVELOPED. ALL MANUFACTURERS ARE FORM A GROUP AND PROTOCOLS ARE STANDARDIZED. ANY RELAY CAN BE COMMUNICATED FOR COMMON COMMUNICATION PROTOCOL, i.e INTEROPERATABULITY. THIS IS SPECIAL FOR AUTOMATION OF STATIONS. Example: 1. IEC 61850
BENIFITS OF UNIVERSAL PROTOCOL One Protocol
ETHERNET & TCP/IP
¾ for all the needs in the substation
¾Adopted worldwide ¾Scalable technology ¾Common use of infrastructure
¾ flexible configuration ¾ no gateways required
Quicker project execution ¾ comprehensive data model ¾ clear, standardised projectand equipment description ¾ Configuration of substation in XML
Separation from Application & Communication ¾data and application stay secure ¾independent from communication systems ¾unconstrained further development of the technology
Efficient maintenance
Innovation & Expansion
¾ robust data modelling ¾ self-descriptive equipment ¾ automation-configuration in XML
¾firm rules for the description of new data- objects and functions ¾Interoperability is maintained
INTEROPERATABULITY WITH ABB, AREVA & SIEMENS
TECHNOLOGY COMPARISION SUBJECT
ELECTROMECHANICAL
Measuring Elements & Hardware
Induction Discs, Electromagnets, Induction cups etc
Measuring Method
Electrical Quantities converted into Mechanical Force & Torque
Timing Function Mechanical Clock works, Dashpot Visual Indication Flags, Targets Trip Command Contacts & Assignments
Additional Trip Relay Required Fixed
STATIC Discrete R L C, Transistors, Analogue ICs, Comparators Level Detectors Comparison with Reference Value in Analogue Comparators
Static Timers LEDs Additional Trip Relay Required Fixed
NUMERICAL Microprocessors, Digital ICs, Digital Signal Processors Analogue to Digital Conversion, Numerical Algorithms, Techniques, Evaluation Trip Criteria Counters LEDs & LCD Display Trip Relays are Inbuilt Freely Configurable
TECHNOLOGY COMPARISION SUBJECT Sequence of Events Hardware Size Parameter Setting
ELECTROMECHANICAL
NUMERICAL
Not Possible
Not Possible
Available
Bulky Plug Setting, Dial Setting
Modular, Compact Thumb Wheel, Potentiometers, DIP Switches Not Available
Most Compact Human Machine Interface, Softwares
Binary Input & Not Available Output Self Supervision Not Available Calibration Frequently Required as settings drift due to ageing
Multiple Characteristics Multiple Integrated Protection func
STATIC
Not Possible
Not Possible
Available & Freely Configurable Available Not required as settings are stored permanently in Memory in Digital Format Possible
Not Possible
Not Possible
Possible
Partially Available Required as settings drift due to ageing
TECHNOLOGY COMPARISION SUBJECT Range of Settings Service value Indication Disturbance Recording Communication facility Burden on CTs, PTs & CVTs
ELECTROMECHANICAL
STATIC
NUMERICAL
Limited
Moderate
Wide
Not Possible
Not Possible
Possible
External Hardware
External Hardware
Inbuilt
Not Possible
Not Possible
Available
Higher
Lower Than Lower Electromechanical & Moderate Protection & Protection Control & Monitoring Monitoring
Protection Control & Monitoring Solution
Only Protection
Fixed
Fixed
Fault History
Not possible
Not Possible
Extension and New development Possible and Open Architecture Stored In Memory
Relay ANSI Numbers (IEEE C37.2) NUMBER
DEVICE
NUMBER
DEVICE
2
Time delay relay
61
Density Switch or Sensor
3
Interlocking relay
63
Pressure Switch
21
Distance Relay
64
Restricted Earth Fault Relay
24
Volts per Hertz Relay
67
Directional Over Current Relay
25
Synchronism Check Relay
68
Blocking/Locking Relay
27
Under Voltage Relay
72
DC Circuit Breaker
29
Isolating Contactor
74
Alarm Relay
30
Annunciation relay
76
DC Over-Current Relay
32
Directional Power Relay
78
Phase Angle measuring or out of step Relay
37
Under Current / Power Relay
79
AC Auto Reclosure Relay
40
Field failure (loss of excitation)
81
Frequency Relay
46
Negative phase sequence Relay
83
Automatic selective control or Transfer Relay
49
M/C or T/F Thermal Relay
84
Operating Mechanism
50
Inst Over-Current Relay
85
Carrier or Pilot wire Receive Relay
51
AC IDMT Over-Current Relay
86
Lockout/Tripping Relay
52
AC Circuit Breaker
87
Differential Relay
53
Exciter or DC Generator Relay
89
Isolator or Disconnector
55
Power Factor Relay
91
Voltage Directional Relay
56
Field Application Relay
92
Voltage or Directional Power Relay
59
Over-Voltage Relay
95
Trip circuit supervision Relay
60
Voltage / Current balance Relay
99
Over-Flux Relay
Power Systems Protection -Introduction
Power Systems Protection -Introduction
Power Evacuation Substation Transmission Substation Switching Substation Distribution Substation
Power Systems Protection -Introduction
Power System Components 1. Generators 2. Transformers 3. Transmission Lines 4. Feeders 5. Motors 6. Capacitor Banks 7. Bus Bars 8. Reactors
Power Systems Protection -Introduction
Why we need the Protection ? ¾ To detect abnormalities (faults). ¾ To eliminate such abnormality by isolating smallest portion of the system in a shortest period of time. ¾ To prevent injury to personnel. ¾ To prevent damage to Equipment. ¾ Enable
Continuous
service
undamaged part of the network.
in
Power Systems Protection -Introduction
Protective Relay – What should it do ? ¾ Monitor system parameters continuously (V, I, P, F) ¾ Operate quickly when necessary (Dependability) ¾ Should not operate wrongly (stability, discrimination)
To trip or not to trip ?
Power Systems Protection -Introduction
Protective System – What are the Requirements? ¾ Speed The relay must operate at the required speed. It should neither be too slow which may result in damage to the equipment nor should it be too fast which may result in undesired operation. Damage can be Minimised.
¾ Sensitivity The relaying equipment must be sufficiently sensitive so that it operates reliably when required under the actual conditions that produces least operating tendency and to detect all possible Shunt and series Faults.
¾ Selectivity The relay must be able to discriminate (select) between those conditions for which prompt operation is required and those for which no operation, or time delayed operation is required. Isolate only Faulty Section without disturbing Healthy Section.
¾ Reliability The most important requisite of protective relay is reliability since they supervise the circuit for a long time before a fault occurs; if a fault then occurs, the relays must respond instantly and correctly. The Operation Capability of the Protection System is summerised in “ reliability”, which includes both the security in fault clearance and the security against undesired clearances. The security in fault clearance is called dependability and the security against undesired clearances is called Security.
Power Systems Protection -Introduction
Protective Relay Scheme – What is it ? ¾ ¾ ¾ ¾ ¾ ¾ ¾
A Protective Relay CT / CVT / PT(EMVT) Auxiliary Power Supply (24 V to 240 V AC/ DC) Switching Device ( Breaker/ Isolator / Contactor) Trip Coil Alarm / Trip contact Control Wiring
Power Systems Protection -Introduction
Power System - Faults Current Over Load Over Current Earth Fault Current Unbalance Dir. Over Current Dir. Earth Fault Power Active power Reactive power Over power Under power Reverse power
Voltage Over Voltage Under Voltage Voltage Unbalance Neutral shift Computed Over fluxing Loss of field Differential Over Current Restricted E/F Under Impedance
Frequency Over Frequency Under Frequency dF/dT Control/Management Synchronising Load sharing Islanding Load shedding
DC Relays
Power Systems Protection -Introduction
Protection – ANSI Codes
Code numbers Used to denote Protections On a SLD
Power Systems Protection -Introduction
Power System – Fault Handling
Trip & Isolate Breaker is tripped on fault Faulty section is isolated
Control & Regulate Breaker is not tripped Corrective actions Generated on line
Power Systems Protection -Introduction
Relay operation when a fault occurs ¾ Each Relay should Protect a specific Zone in the System. ¾ If fault is inside its Zone, Relay should operate and isolate the faulted Zone. ¾ If fault is outside zone, Relay should not operate, Some other Relay should operate and isolate
Power Systems Protection -Introduction
What happens when a fault occurs ¾ Fault current flows through number of Relays. ¾ Some of operate.
these
Relays
will
start
to
¾ Only one Relay related to particular fault should trip and interrupt the fault current. ¾ Remaining Relays will reset after above.
Power Systems Protection -Introduction
Protection Relays – Inputs / Out puts Inputs Current Voltage Frequency Power
CTs PTs PTs CTs + PTs
Outputs Trip Contact
Power Systems Protection -Introduction
Protection Relays – Settings Pick up setting
Low set Highset
Time delay setting
Definite time Inverse time
% of CT Rating
TMS Setting
Power Systems Protection -Introduction
Power System – Trip time characteristics
t
1.3 or 3.0 sec
1.4 LS
10
I/Is
Power Systems Protection -Introduction
Power System – Trip time characteristics
t
1.3 or 3.0 sec
50 msec
1.4 LS
6 HS
10
I/Is
Power Systems Protection -Introduction
Typical Inverse Time Delays TIME MULTIPLIER SETTING – TMS : 1.00 I/Is=2 I/Is=4 I/Is=6 I/Is=8 I/Is=10 I/Is=15 I/Is=20 Normal Inv 3 sec
10.13
5.03
3.87
3.33
3.00
2.54
2.29
Normal Inv 1.3 sec
04.39
2.18
1.68
1.44
1.30
1.10
0.99
Very Inverse 1.5 sec
13.50
4.50
2.70
1.93
1.50
0.96
0.71
Extremely Inverse
26.66
5.33
2.28
1.27
0.81
0.36
0.20
Power Systems Protection -Introduction
Things you should know Application SLD representation Front panel Controls Back Panel terminations Inputs / Outputs / Ratings Settings (Inside) Settings (on front panel) Installation & wiring Commissioning Testing (Front panel) Testing (SCITS) Cat . No.
EVALUATION OF PROTECTIVE RELAYS PREPARED BY GOPALA KRISHNA PALEPU ADE/MRT(PROTECTION)
1 ST GENERATION FIRST GENERATION RELAYS : THESE ARE ELECTRO MAGNETIC RELAYS IN THIS NO OF ELECTROMAGNETIC RELAYS PROVIDED FOR ARRIVING A SPECIFIC FUNCTION i.e EACH FUNCTION OF THE SCHEME HAVING A SEPARATE RELAY. COMBINING ALL IS CALLED ONE PROTECTION FUNCTION. NO OF RELAYS ARE MORE AND SPACE OCUPATION IS MORE AND INTER CONNECTION WIRING DIAGRAM IS MORE. DISADVANTAGES: ELECTROMECHANICAL RELAYS HAVE A LOT OF MECHANICAL PARTS, WHICH MAY BECOME CLOGGED WITH DIRT OR CORRODED DUE TO ENVIRONMENTAL CONDITIONS, AFFECTING BOTH OPERATION, CALIBRATION AND MOVEMENT OF THE DISKS. IT REQUIRES PERIODICAL MAINTANENCE AND ADJUSTMENT.
1 ST GENERATION NEXT MODIFICATION : ELECTRO MAGNETIC RELAYS WITH STATIC COMPONENTS IN THIS SOME OF THE FUNCTIONS ARE DERIVED FROM STATIC COMPONENTS PROVIDED ON THE PCB. IN THIS QUANTITY OF ELECTROMAGNETIC RELAYS ARE REDUCED. COMBINING ALL IS CALLED ONE PROTECTION FUNCTION. QUANTITY OF RELAYS ARE REDUCED AND SPACE OCUPATION IS REDUCED SOME WHAT. DISADVANTAGES: THE PCBs ARE MADE WITH TRANSISTORS AND ARE BROUGHTOUT ITEMS WITH DIFFERENT MAKE. AFTER SOME TIME THESE ARE TO BE REPLACED FOR CORRECT OPERATION WITHOUT DRIFT. THE PCBs & COMPONENTS PERFORMANCE MAY BE AFFECTED DUE TO DIST & DIRT. IT REQUIRES PERIODICAL MAINTANENCE AND ADJUSTMENT.
2 ND GENERATION SECOND GENERATION RELAYS : STATIC RELAYS WITH TRANSISTORS In this all of the functions are derived from static components provided on the PCB. In this initially each function is derived with separate static relay. Quantity of static relays are more but space occupation is less. Combining all is called one protection function. Inter connection wiring diagram is still not reduced. DISADVANTAGES: Static relays generally employ a lot of electronic components made by other manufacturers. If these electronic components are not tested with rigorous quality control, the chances of failure of components during the relay life time may exist. A reliable DC power source within the relay, to electronically measure circuits has to be generated from available external power sources. Most of the static relays employ series, shunt, or switched mode power supply designs. For a variety of reasons, if these power supplies fail, the measuring circuits are inoperative and the relay is dead for any measurements. No protection is available to the network. Most of the static relays in use do not have the means to detect the failure of power supply and initiate an alarm. It requires periodical Maintenance.
2 ND GENERATION NEXT MODIFICATION : STATIC RELAYS ON SINGLE PCB IN THIS ALL OF THE FUNCTIONS ARE DERIVED FROM STATIC COMPONENTS PROVIDED ON THE PCB. IN THIS ALL STATIC RELAYS ARE TAKEN TO ONE MASTER PCB AND EACH FUNCTION PCB WILL BE ADD ON CARD TYPE. SO TOTAL RELAY IS ONE BUT FOR EVERY FUNCTION IS PCB IS AVAILABLE AND CONNECTED TO MAIN PCB. SPACE OCCUPATION IS LESS. COMBINING ALL IS CALLED ONE PROTECTION FUNCTION. NO INTER CONECTION WIRING. THIS IS PART OF MAIN PCB. DISADVANTAGES: DISADVANTAGES ARE SAME AS ABOVE.
3 ND GENERATION THIRD GENERATION RELAYS : STATIC RELAYS WITH ICs IN THIS NO OF COMPONENTS ARE REDUCED AND BROUGHT OR BUILT IN ONE INTEGRATED CHIP. DUE TO THIS THE RELAY SIZE IS REDUCED AND SOME OF THE FUNCTIONS ALSO TAKEN IN TO ONE INTEGRATED CHIP. THIS ALSO BUILT IN ONE PCB. ALL OF THE FUNCTIONS ARE DERIVED FROM STATIC COMPONENTS PROVIDED ON THE PCB. IN THIS ONLY MASTER PCB IS AVAILABLE, NO SEPARATE PCB FOR EACH FUNCTION , ALL ARE INTEGRATED IN ONE PCB. PROBLEMS ARE SOME WHAT REDUCED. SPACE OCCUPATION IS LESS. ONE PROTECTION FUNCTION ONLY ONE RELAY AND ALL FUNCTIONS ARE INTEGRATED. NO INTER CONNECTION WIRING DIAGRAM.
3 ND GENERATION NEXT MODIFICATION : SEMI NUMERIC RELAYS IN THIS SOME FUNCTIONS ARE CAN BE PROGRAMMABLE AND INTERFACE THROUGH PC. SOME ICs ARE HAVING THE FACILITY TO INTERACT THROUGH COMMUNICATION PORT. IT IS SOME WHAT MODIFICATION TO IC BASED RELAYS. IN THIS SOME FUNCTION CAN BE ENABLED AND DISABLED, BASED ON THE REQUIREMENT.
4 ND GENERATION MICROPROCESSOR BASED NUMERICAL RELAYS ¾ IN THIS ALL OF THE FUNCTIONS ARE BROUGHT ON ONE IC. THE FOURTH GENERATION PROCESSORBASED RELAYS, DO HAVE THE WATCHDOG FEATURE, WHICH FACILITATES THE CHECKING OF POWER SUPPLY FAILS, CLOCK FREQUENCIES, AND OTHER PATTERNS. MOST OF THESE RELAYS HAVE AUTO TEST FEATURES WHICH TEST THE ELECTRONIC CIRCUIT FUNCTIONS AT REGULAR INTERVALS & AUTOMATICALLY.
MICROPROCESSOR BASED RELAYS ¾ BACK GROUND WORK ¾ ADVANTAGES & DISADVANTAGES ¾ OPERATIONS & ALGORITHMS IN MICROPROCESSOR ¾ FUNCTIONAL BLOCKS & OTHER HARDWARE OF MICROPROCESSOR BASED RELAY ¾ FILTERING TECHNIQUES ¾ TESTING OF MICROPROCESSOR RELAYS
MICROPROCESSOR BASED RELAYS - BACKGROUND WORK
1960s ¾ A FEW CONCEPTS WERE PROPOSED ¾ HARDWARE WAS VERY EXPENSIVE ¾ BENEFITS OF MICROPROCESSORS FOR RELAYS WERE NOT CLEAR ¾ IEEE ARTICLE “FAULT PROTECTION WITH A DIGITAL COMPUTER” OUTLINED THE FEASIBILITY & PROBLEMS ASSOCIATED IN S/S PROTECTION WHEN A DIGITAL COMPUTER IS USED.
MICROPROCESSOR BASED RELAYS - BACKGROUND WORK
1970s ¾
TWO PAPERS WERE PUBLISHED “DIGITAL CALCULATION OF IMPEDANCE FOR TRANSMISSION LINE PROTECTION” “ 3 PH TRANSMISSION LINE PROTECTION WITH A DIGITAL COMPUTER”
¾
PROMINENT MANUFACTURERS LIKE WESTINGHOUSE, IBM STARTED INVESTIGATING S/S COMPUTER SYSTEMS
¾
PHILADELPHIA ELECTRIC & GE INITIATED PROJECTS ON DIGITAL TECHNIQUES FOR PROTECTION
¾
VARIOUS ALGORITHMS WERE DERIVED FOR DIGITAL CALCULATION OF PROTECTION PARAMETRS
¾
EXPERIMENTAL SYSTEMS WERE BUILT BY GE & WESTINGHOUSE TO CHECK ALGORITHMS
¾
FIRST GENERATION OF MICROPROCESSOR BASED RELAYS BUILT
MICROPROCESSOR BASED RELAYS - BACKGROUND WORK 1980s ¾
MAJOR MANUFACTURERS LIKE ABB, GE, GEC , TOSHIBA, SIEMENS START DESIGN & SALES OF BROAD RANGE OF PRODUCTS FOR POWER SYSTEM PROTECTION
¾
MICROPROCESSOR IMPROVES PERFORMANCE SPECS FOR OPERATION IN INDUSTRIAL ENVIRONMENT
¾
MANY PLC BASED SYSTEMS ARE COMMISSIONED IN INDIA BY L&T, SIEMENS, ECIL ETC.
¾
MANY ELECTRICITY BOARDS & PROCESS PLANTS IN INDIA START USING MICROPROCESSOR BASED INSTRUMENTS
¾
THE WORD SCADA GETS POPULAR IN INDIA
¾
PGCIL GOES IN FOR MICROPROCESSOR BASED DISTANCE RELAYS IN INDIA
MICROPROCESSOR BASED RELAYS - BACKGROUND WORK 1990s ¾
ABB & GEC ALSTOM MICROPROCESSOR BASED PROTECTIONS
¾
MAJOR MANUFACTURERS LIKE ABB, GE, GEC , TOSHIBA STARTS DESIGN & SALES OF BROAD RANGE OF PRODUCTS FOR POWER SYSTEM PROTECTION
¾
MANY ELECTRICITY BOARDS & PROCESS PLANTS IN INDIA START USING MICROPROCESSOR BASED INSTRUMENTS
¾
PGCIL GOES IN FOR MICROPROCESSOR BASED DISTANCE RELAYS IN INDIA
¾
MICROCONTROLLERS / DSPs ARE INTRODUCED IN LATE 90s BY HARDWARE MANUFACTURERS WHICH HAVE IMPROVED THE SPEED OF OPERATION.
INTRODUCED RANGE OF RELAYS FOR ALL UNIT
ADVANTAGES OF NUMERIC RELAYS PARAMETER
NUMERIC
CONVENTIONAL
ACCURACY BURDEN SETTING RANGES MULTI FUNCTIONALITY SIZE FIELD PROGRAMMABILITY PARAMETER DISPLAY SYSTEM FLEXILBILITY CO-ORDINATION TOOLS COMMUNICATION REMOTE CONTROL SPECIAL ALGORITHMS SPECIAL PROTECTIONS SELF DIAGNOSTICS
1% < 0.5 VA WIDE YES SMALL YES YES YES MANY YES YES MANY YES YES
5% / 7.5% > 5 VA LIMITED NO LARGE NO NO NO TWO NO NO LIMITED NO NO
DIS-ADVANTAGES OF NUMERIC RELAYS
SOFTWARE INTENSIVE OBSOLESENCE RATE EMI / EMC PROBLEMS SERIAL NATURE
PROTECTION ALGORITHM
MEASUREMENMT METHOD TRIP TIME CALCULATION GOOD FILTERING CHARACTERISTIC (HARMONICS, NOISE, DC SHIFT) FAST TRIP DECISION
FUNCTIONAL BLOCKS OF A NUMERIC RELAY
ANALOG INPUT SU-SYSTEM
RAM
D S P MICRO PROCESSOR
DIGITAL INPUT SUB-SYSTEM
POWER SUPPLY
ROM EPROM FLASH
DIGITAL OUTPUT SUB-SYSTEM
COMMUNICATION INTERFACE
ANALOG INPUT SUB SYSTEM
CT
SURGE SUPPRESSION
ANALOG FILTER MUX
PT
SURGE SUPPRESSION
ANALOG FILTER
A/D CONVERTER
MICRO PROCESSOR
MICROPROCESSORS Vs MICRO CONTROLERS Microprocessor
Micro controller Address Register
Address Register C O N T R O L
Data Register Arithmetic Logic Unit Accumulator
C O N T R O L
Data Register Arithmetic Logic Unit Accumulator
ROM Timers I/O RAM Counters EPROM UART
RELAY HARDWARE 16 / 32 BIT
PC MODEM
IRIG-B RE/CC
NORMALLY 400KV RELAYS SUPPLIED WITH CONFIGUARATION/HARDWARE 1. MIN 4Nos MAX 8Nos COMMAND/TRIP OUTPUTS 2. MIN 24Nos SIGNAL OUTPUTS 3. MIN 14 LED INDICATIONS 4. MIN 24 BINARY INPUTS
FOLLOWING
SELF DIAGNOSTICS - TECHNIQUES USED RAM
Checked by computing a checksum of memory contents and comparing it against a stored factory value.
RAM
Checked by periodically writing a specific data and reading back the memory contents
A/D
Checked by inputing a known value of + / - voltage. Any off set at a given time, is software corrected.
SETTINGS
Checked by checksums or CRC values can be stored and compared. Often, 2 or 3 copies of settings are stored and compared.
POWER SUPPLY
Checked by monitoring power supply voltage values from A / D converter.
TYPES OF SIGNALS REQUIRED FOR PROPER PROTECTION
Current, Voltage and Distance Relays : Require fundamental frequency component signals. All other signals will interfere with protection process.
Harmonic Restraint Relays : Require both the fundamental & the Harmonic components , each value separately, for decision making process.
4 ND GENERATION ¾ 1ST DEVELOPMENT: SOFTWARE DEVELOPMENT IS APPLICATION BASED RELAYS i.e EACH PROTECTION FUNCTION HAVING SEPARATE SOFTWARE & HARDWARE. ¾ Example: 1. LINE PROTECTION, 2. TRANSFORMER PROTECTION, 3. BUSBAR PROTECTION, 4. GENERATOR PROTECTION 5. MOTOR PROTECTION 6. REACTOR PROTECTION 7. CAPACITOR PROTECTION
4 ND GENERATION ¾ 2ND DEVELOPMENT: SOFTWARE DEVELOPMENT IS SOME GROUP BASED RELAYS i.e SOME PROTECTION FUNCTIONS ARE TAKEN IN TO ONE FLATFORM AND PROVIDED COMMON SOFTWARE. FROM THIS INBUILT FACILITY OF EVENT RECORDER AND DISTURBANCE RECORDER IS DEVELOPED. ¾ Example: ABB: 1. REX 5xx SERIES FLATFORM 2. REX 316 SERIES FLATFORM 3. REX 670 SERIES FLATFORM 4. RED 500 SERIES FLATFORM 5. RED 600 SERIES FLATFORM
4 ND GENERATION ¾ 3RD DEVELOPMENT: UNIVERSAL SOFTWARE FOR ALL TYPES OF RELAYS FOR PARTICULAR MANUFACTURER. i.e. ONE SOFTWARE ONE MANUFACTURER. ¾ Example: 1. SIEMENS: SIPROTEC SERIES – DIGSI 2. GE MULTILIN: ENERVISTA 3. AREVA : MICOM S1
4 ND GENERATION ¾ 4TH DEVELOPMENT: UNIVERSAL HARDWARE FOR ALL TYPES OF RELAYS FOR PARTICULAR MANUFACTURER. ONE HARDWARE FOR ONE MANUFACTURER. BUT IT IS MODULAR DESIGN. RELAY IS COMMON HARDWARE BASED ON PROTECTION FUNCTION, PARTICULAR CARD IS ADDED. ¾ Example: 1. GE MULTILIN: UR SERIES & SR SERIES
4 ND GENERATION ¾ 5TH DEVELOPMENT: EACH MANUFACTURER ADOPTING THEIR PROPERITIERY BASED PROTOCOL FOR COMMUNICATION, INTERFACING, NETWORKING AND AUTOMATION. SOME UTILTIES ARE REQUESTED MANUFACTURERS TO SUIT THEIR ADOPTED PROTOCOL. ¾ Example: 1. UCA – Utility communication architecture 2. LON 3. SPA 4. PROFIBUS 5. MODBUS 6. DNP 7. FIELDBUS 8. MVB 9. IEC 60870
4 ND GENERATION ¾ 6TH DEVELOPMENT: BASED ON THE EXPERIENCE WITH DIFFERENT PROTOCOLS, NEED FOR UNIFORMITY AND KNOW – HOW FOR GLOBAL CONSIDERATION ONE WORLD ONE TECHNOLOGY ONE STANDARD A UNIVERSAL PROTOCOL FOR COMMUNICATION, INTERFACING AND NETWORKING IS DEVELOPED. ALL MANUFACTURERS ARE FORM A GROUP AND PROTOCOLS ARE STANDARDIZED. ANY RELAY CAN BE COMMUNICATED FOR COMMON COMMUNICATION PROTOCOL, i.e INTEROPERATABULITY. THIS IS SPECIAL FOR AUTOMATION OF STATIONS. Example: 1. IEC 61850
BENIFITS OF UNIVERSAL PROTOCOL One Protocol
ETHERNET & TCP/IP
¾ for all the needs in the substation
¾Adopted worldwide ¾Scalable technology ¾Common use of infrastructure
¾ flexible configuration ¾ no gateways required
Quicker project execution ¾ comprehensive data model ¾ clear, standardised projectand equipment description ¾ Configuration of substation in XML
Separation from Application & Communication ¾data and application stay secure ¾independent from communication systems ¾unconstrained further development of the technology
Efficient maintenance
Innovation & Expansion
¾ robust data modelling ¾ self-descriptive equipment ¾ automation-configuration in XML
¾firm rules for the description of new data- objects and functions ¾Interoperability is maintained
INTEROPERATABULITY WITH ABB, AREVA & SIEMENS
TECHNOLOGY COMPARISION SUBJECT
ELECTROMECHANICAL
Measuring Elements & Hardware
Induction Discs, Electromagnets, Induction cups etc
Measuring Method
Electrical Quantities converted into Mechanical Force & Torque
Timing Function Mechanical Clock works, Dashpot Visual Indication Flags, Targets Trip Command Contacts & Assignments
Additional Trip Relay Required Fixed
STATIC Discrete R L C, Transistors, Analogue ICs, Comparators Level Detectors Comparison with Reference Value in Analogue Comparators
Static Timers LEDs Additional Trip Relay Required Fixed
NUMERICAL Microprocessors, Digital ICs, Digital Signal Processors Analogue to Digital Conversion, Numerical Algorithms, Techniques, Evaluation Trip Criteria Counters LEDs & LCD Display Trip Relays are Inbuilt Freely Configurable
TECHNOLOGY COMPARISION SUBJECT Sequence of Events Hardware Size Parameter Setting
ELECTROMECHANICAL
NUMERICAL
Not Possible
Not Possible
Available
Bulky Plug Setting, Dial Setting
Modular, Compact Thumb Wheel, Potentiometers, DIP Switches Not Available
Most Compact Human Machine Interface, Softwares
Binary Input & Not Available Output Self Supervision Not Available Calibration Frequently Required as settings drift due to ageing
Multiple Characteristics Multiple Integrated Protection func
STATIC
Not Possible
Not Possible
Available & Freely Configurable Available Not required as settings are stored permanently in Memory in Digital Format Possible
Not Possible
Not Possible
Possible
Partially Available Required as settings drift due to ageing
TECHNOLOGY COMPARISION SUBJECT Range of Settings Service value Indication Disturbance Recording Communication facility Burden on CTs, PTs & CVTs
ELECTROMECHANICAL
STATIC
NUMERICAL
Limited
Moderate
Wide
Not Possible
Not Possible
Possible
External Hardware
External Hardware
Inbuilt
Not Possible
Not Possible
Available
Higher
Lower Than Lower Electromechanical & Moderate Protection & Protection Control & Monitoring Monitoring
Protection Control & Monitoring Solution
Only Protection
Fixed
Fixed
Fault History
Not possible
Not Possible
Extension and New development Possible and Open Architecture Stored In Memory
Relay ANSI Numbers (IEEE C37.2) NUMBER
DEVICE
NUMBER
DEVICE
2
Time delay relay
61
Density Switch or Sensor
3
Interlocking relay
63
Pressure Switch
21
Distance Relay
64
Restricted Earth Fault Relay
24
Volts per Hertz Relay
67
Directional Over Current Relay
25
Synchronism Check Relay
68
Blocking/Locking Relay
27
Under Voltage Relay
72
DC Circuit Breaker
29
Isolating Contactor
74
Alarm Relay
30
Annunciation relay
76
DC Over-Current Relay
32
Directional Power Relay
78
Phase Angle measuring or out of step Relay
37
Under Current / Power Relay
79
AC Auto Reclosure Relay
40
Field failure (loss of excitation)
81
Frequency Relay
46
Negative phase sequence Relay
83
Automatic selective control or Transfer Relay
49
M/C or T/F Thermal Relay
84
Operating Mechanism
50
Inst Over-Current Relay
85
Carrier or Pilot wire Receive Relay
51
AC IDMT Over-Current Relay
86
Lockout/Tripping Relay
52
AC Circuit Breaker
87
Differential Relay
53
Exciter or DC Generator Relay
89
Isolator or Disconnector
55
Power Factor Relay
91
Voltage Directional Relay
56
Field Application Relay
92
Voltage or Directional Power Relay
59
Over-Voltage Relay
95
Trip circuit supervision Relay
60
Voltage / Current balance Relay
99
Over-Flux Relay
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