BECKWITH ELECTRIC M-3520 User manual

Instruction Book
M-3520 Intertie
Protection Relay

Intertie Protection
M-3520
PROTECTION
Unit shown with optional HMI and Target modules
• Integrated Protection System for DR/DG Intertie, Providing:
Loss of parallel utility operation protections
Abnormal power flow protections
Comprehensive suite of phase and ground fault backed protections
Abnormal operating protections
Reconnect and Sync Check functions
• Microprocessor-based Intertie Protection Relay integrates protection,
metering, monitoring and waveform capture
• Provides 18 base protective relay functions and 3 optional protective
functions
• Local and remote serial communications capabilities, plus IRIG-B
interface
Integrated Protection System®

–2–
M-3520 Intertie Protection Relay
Standard Functions
• Sync check with Phase, ΔV and ΔF with deadline/deadbus options (25)
• Phaseundervoltage(27)protection
• Neutralover/undervoltage(59G/27G)protection
• Sensitivedual-setpoint, reverse power detection (32)
• Sensitivenegative-sequenceovercurrent protection and alarm (46)
• Negativesequencevoltage(47)
• Instantaneousovercurrent(50)protection
• Instantaneousneutralovercurrent(50G)protection
• Three-phaseinverse time overcurrent (51V) withvoltage control/voltage restraint
• Neutralinversetime overcurrent (51G) protection
• Phaseovervoltage(59) protection
• Peakovervoltage (59I) protection
• VT fuse-loss detection and blocking (60FL)
• Directionalinverse and definite time phase overcurrent (67)
• Directionalinverse and definite time neutral overcurrent(67N)
• Reconnectenable(79)
• Over/Underfrequency(81O/U)
Optional Functions
• Dual–zonephase distance protection for phase fault backup (21)
• Out of Step (78)
• Rateof change of frequency (81R)
Standard Features
• Eightprogrammable outputs and six programmable inputs
• Oscillographrecording
• 32-targetstorage
• Meteringofall measured parameters
• Threecommunicationsports (two RS-232, one RS-485)
• Standard19"rack-mount design
• Removableprintedcircuit board and power supply
• Both 50 and 60 Hz models available
• Both 1 and 5 Amp rated CT inputs available
• M-3822IPScom®CommunicationsSoftware
• IRIG-B time synchronization
Optional Features
• Redundantpowersupply
• M-3915TargetModule
• M-3931Human-MachineInterfaceModule
• M-3801D IPSplot® PLUS Oscillograph Analysis Software
• 4-WireRS-485Connection

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M-3520 Intertie Protection Relay
STANDARD FUNCTIONS
Device Setpoint
Number Function Ranges Increment Accuracy†
Sync CheckSync Check
Sync CheckSync Check
Sync Check
Phase Angle Window 0° to 90° 1° &1°
Upper Voltage Limit 60 to 140 V 1 V &0.5 V or &0.5%
Lower Voltage Limit 40 to 120 V 1 V &0.5 V or &0.5%
Delta Voltage Limit 1.0 to 50.0 V 0.1 V &0.5 V
Delta Frequency Limit 0.001 to 0.500 Hz 0.001 Hz &0.0007 Hz or 5%
Sync Check Time Delay 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
Dead Voltage Limit 0 to 60 V 1 V &0.5 V
Dead Time Delay 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
Sync Check may be operated as a stand-alone function or supervised by 79 (reconnect). Various combi-
nations of input supervised hot/dead closing schemes may be selected.
UndervoltageUndervoltage
UndervoltageUndervoltage
Undervoltage
Pickup #1, #2 5 to 180 V 1 V &0.5 V or &0.5%
&0.8 V or &0.75%*
Time Delay #1, #2 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
* When line-ground to line-line is selected.
Neutral UndervoltageNeutral Undervoltage
Neutral UndervoltageNeutral Undervoltage
Neutral Undervoltage
Magnitude 5 to 180 V 1 V &0.5 V or &0.5%
Time Delay 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
Reverse/Forward PowerReverse/Forward Power
Reverse/Forward PowerReverse/Forward Power
Reverse/Forward Power
Pickup #1, #2 -3.000 to +3.000 PU 0.001 PU &0.002 PU or 2%
Time Delay #1, #2 1 to 8160 Cycles 1 Cycle +16 Cycles or &1%
The per-unit pickup is based on nominal VT secondary voltage and nominal CT secondary current settings.
Single phase detection may be selected for line-to-ground connected VTs. This function can be selected as
either overpower or underpower in the forward direction (positive setting) or reverse direction (negative setting).
Negative Sequence OvercurrentNegative Sequence Overcurrent
Negative Sequence OvercurrentNegative Sequence Overcurrent
Negative Sequence Overcurrent
Definite Time
Pickup 0.10 to 20.00 A 0.01 A &0.1 A or &3%
(0.02 to 4.00 A) (&0.02 A or &3%)
Time Delay 1 to 8160 Cycles 1 Cycle –1 to + 3 Cycles or &3%
Inverse Time
Pickup 0.50 to 5.00 A 0.01 A &0.1 A or &3%
(0.10 to 1.00 A) (&0.02 A or &3%)
Characteristic Curves Definite Time/Inverse/Very Inverse/Extremely Inverse/IEC Curves
Time Dial 0.5 to 11.0 0.1 &3 Cycles or &5%
0.05 to 1.10 (IEC curves) 0.01
Negative Sequence OvervoltageNegative Sequence Overvoltage
Negative Sequence OvervoltageNegative Sequence Overvoltage
Negative Sequence Overvoltage
Pickup #1, #2 5 to 180 V 1 V &0.5 V or &0.5%
Time Delay #1, #2 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
27
46
47
†Select the greater of these accuracy values. Values in parentheses apply to 1 Amp CT secondary rating.
25
27G
32

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M-3520 Intertie Protection Relay
STANDARD FUNCTIONS ( cont .)
Device Setpoint
Number Function Ranges Increment Accuracy†
Instantaneous Phase OvercurrentInstantaneous Phase Overcurrent
Instantaneous Phase OvercurrentInstantaneous Phase Overcurrent
Instantaneous Phase Overcurrent
Pickup 1.0 to 240.0 A 0.1 A &0.1 A or &3%
(0.2 to 48.0 A) (&0.02 A or &3%)
Time Delay 2 Cycles — &2 Cycles
Instantaneous Neutral OvercurrentInstantaneous Neutral Overcurrent
Instantaneous Neutral OvercurrentInstantaneous Neutral Overcurrent
Instantaneous Neutral Overcurrent
Pickup 0.5 to 240.0 A 0.1 A &0.1 A or &3%
(0.1 to 48.0 A) (&0.02 A or &3%)
Time Delay 2 Cycles — &2 Cycles
The 50G can be supervised by the ground directional element (if 67N option is selected).
Inverse Time Neutral OvercurrentInverse Time Neutral Overcurrent
Inverse Time Neutral OvercurrentInverse Time Neutral Overcurrent
Inverse Time Neutral Overcurrent
Pickup 0.25 to 12.00 A 0.01 A &0.1 A or &3%
(0.05 to 2.40 A) (&0.02 A or &3%)
Characteristic Curve Definite Time/Inverse/Very Inverse/Extremely Inverse/IEC Curves
Time Dial 0.5 to 11.0 0.1 &3 Cycles or &5%
0.05 to 1.10 (IEC curves) 0.01
The 51G can be supervised by the ground directional element.
Inverse Time Overcurrent, with Voltage Control or Voltage RestraintInverse Time Overcurrent, with Voltage Control or Voltage Restraint
Inverse Time Overcurrent, with Voltage Control or Voltage RestraintInverse Time Overcurrent, with Voltage Control or Voltage Restraint
Inverse Time Overcurrent, with Voltage Control or Voltage Restraint
Pickup 0.50 to 12.00 A 0.01 A &0.1 A or &3%
(0.10 to 2.40 A) (&0.02 A or &3%)
Characteristic Curve Definite Time/Inverse/Very Inverse/Extremely Inverse/IEC Curves
Time Dial 0.5 to 11.0 0.1 &3 Cycles or &5%
0.05 to 1.10 (IEC curves) 0.01
Voltage Control (VC) 5 to 180 V 1 V &0.5 V or &5%
or
Voltage Restraint (VR) Linear Restraint — —
OvervoltageOvervoltage
OvervoltageOvervoltage
Overvoltage
Pickup #1, #2 5 to 180 V 1 V &0.5 V or &0.5%
&0.8 V or &0.75%*
Time Delay #1, #2 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
* When line-ground to line-line is selected.
Neutral OvervoltageNeutral Overvoltage
Neutral OvervoltageNeutral Overvoltage
Neutral Overvoltage
Pickup 5 to 180 V 1 V &0.5 V or &0.5%
Time Delay 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
Peak OvervoltagePeak Overvoltage
Peak OvervoltagePeak Overvoltage
Peak Overvoltage
Magnitude 1.05 to 1.50 PU 0.01 PU &0.03 PU*
Time Delay 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
Instantaneous voltage magnitude response; intended for ferroresonance protection.
*For fundamental (60 Hz/50 Hz) signal only. For distorted input signals, the accuracy degrades as the
order of the harmonic signal increases. The accuracy applies to voltages below 180 V.
†Select the greater of these accuracy values. Values in parentheses apply to 1 Amp CT secondary rating.
50
50G
51G
59
51V
59G
59I

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M-3520 Intertie Protection Relay
STANDARD FUNCTIONS ( cont .)
Device Setpoint
Number Function Ranges Increment Accuracy†
VT Fuse–Loss DetectionVT Fuse–Loss Detection
VT Fuse–Loss DetectionVT Fuse–Loss Detection
VT Fuse–Loss Detection
A VT fuse loss condition is detected by using the positive and negative sequence components
of the voltages and currents. VT fuse loss output can be initiated from internally generated logic
or from input contacts.
Time Delay 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
Phase Directional OvercurrentPhase Directional Overcurrent
Phase Directional OvercurrentPhase Directional Overcurrent
Phase Directional Overcurrent
Definite Time*
Pickup 1.0 to 240.0 A 0.1 A &0.1 A or 3%
(0.2 to 48.0 A) (&0.02 A or 3%)
Time Delay 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
Inverse Time
Pickup 0.50 to 12.00 A 0.01 A &0.1 A or &3%
(0.10 to 2.40 A) (&0.02 A or &3%)
Characteristic Curve Definite Time/Inverse/Very Inverse/Extremely Inverse/IEC Curves
Time Dial Setting 0.5 to 11.0 0.1 &3 Cycles or &5%
0.05 to 1.10 (IEC curves) 0.01
Phase Directional Element
Maximum Sensitivity
(Torque) Angle (MSA) 0° to 359° 1°
*High speed operation results when delay programmed for one cycle; response time = less than 1–1/2
cycles.
Directional sensing for 67DT or 67IT may be disabled. Sensitivity at MSA is 0.5 VA, uses Positive
Sequence Voltage and current for polarization, prefault memory 8 cycles.
Residual Directional Overcurrent
Definite Time*
Pickup 0.5 to 240.0 A 0.1 A &0.1 A or 3%
(0.1 to 48.0 A) (&0.02 A or &3%)
Time Delay 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
Inverse Time*
Pickup 0.25 to 12.00 A 0.01 A &0.1 A or &3%
(0.05 to 2.40 A) (&0.02 A or &3%)
Characteristic Curve Definite Time/Inverse/Very Inverse/Extremely Inverse/IEC Curves
Time Dial 0.5 to 11.0 0.1 &3 Cycles or &5%
0.05 to 1.10 (IEC Curves) 0.01
Ground Directional Element
Max. Sensitivity Angle (MSA) 0 to 359° 1°
Polarization** 1 to 5 1
*Directional control for 67NDT or 67NIT may be disabled.
** Polarization can be zero sequence, negative sequence, current (polarized) or dual polarized. Polariza-
tions 1, 3 and 5 shall not be used with L-L and L-G to L-L VT selection. When using polarizations 4 or 5,
MSA is not applicable and should be set to zero.
†Select the greater of these accuracy values. Values in parentheses apply to 1 Amp CT secondary rating.
60
FL
67N
67

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M-3520 Intertie Protection Relay
STANDARD FUNCTIONS ( cont .)
Device Setpoint
Number Function Ranges Increment Accuracy†
Reconnect Enable Time DelayReconnect Enable Time Delay
Reconnect Enable Time DelayReconnect Enable Time Delay
Reconnect Enable Time Delay
Reconnect Delay 2 to 65500 Cycles 1 Cycle –1 to +3 Cycles or &1%
Reconnect timer starts when all outputs designated as trip outputs dropout.
FrequencyFrequency
FrequencyFrequency
Frequency
Pickup #1, #2, #3, #4 50.00 to 67.00 Hz 0.01 Hz &0.02 Hz
40.00 to 57.00 Hz*
Time Delay #1,#2, #3, #4 2 to 65,500 Cycles 1 Cycle –2 to +3 Cycles or &1%
The pickup accuracy applies to 60 Hz models at a range of 57 to 63 Hz, and to 50 Hz models at a range
of 47 to 53 Hz. Beyond these ranges, the accuracy is
& 0.1 Hz.
*This range applies to 50 Hz nominal frequency models.
†Select the greater of these accuracy values. Values in parentheses apply to 1 Amp CT secondary rating.
81
79

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M-3520 Intertie Protection Relay
OPTIONAL FUNCTIONS
Device Setpoint
Number Function Ranges Increment Accuracy†
Phase Distance (dual–zone mho characteristic)Phase Distance (dual–zone mho characteristic)
Phase Distance (dual–zone mho characteristic)Phase Distance (dual–zone mho characteristic)
Phase Distance (dual–zone mho characteristic)
Circle Diameter #1, #2 0.1 to 100.0 Ω0.1 Ω&0.1 Ωor &5%
(0.5 to 500.0 Ω)(&0.5 Ωor &5%)
Offset #1, #2 –100.0 to 100.0 Ω0.1 Ω&0.1 Ωor &5%
(–500.0 to 500.0 Ω)(&0.5 Ωor &5%)
Impedance Angle #1, #2 0° to 90° 1° &1°
Time Delay #1, #2 1 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
Out of Step (mho characteristic)Out of Step (mho characteristic)
Out of Step (mho characteristic)Out of Step (mho characteristic)
Out of Step (mho characteristic)
Circle Diameter 0.1 to 100.0 Ω0.1 Ω&0.1 Ωor 5%
(0.5 to 500.0 Ω)(&0.5 Ωor 5%)
Offset –100.0 to 100.0 Ω0.1 Ω&0.1 Ωor 5%
(–500.0 to 500.0 Ω)(&0.5 Ωor 5%)
Impedance Angle 0° to 90° 1° &1°
Blinder 0.1 to 50.0 Ω0.1 Ω&0.1 Ωor 5%
(0.5 to 250.0 Ω)(&0.5 Ωor 5%)
Time Delay 1 to 8160 Cycles 1 Cycle &1 Cycle or &1%
Trip on mho Exit Enable/Disable
Pole Slip Counter 1 to 20 1
Pole Slip Reset 1 to 8160 Cycles 1 Cycle &1 Cycle or &1%
Rate of Change of FrequencyRate of Change of Frequency
Rate of Change of FrequencyRate of Change of Frequency
Rate of Change of Frequency
Pickup #1, #2 0.10 to 20.00 Hz/Sec 0.01 Hz/Sec &0.05 Hz/Sec or &5%
Time Delay #1, #2 1 to 8160 Cycles 1 Cycle +20 Cycles
Negative Sequence
Voltage Inhibit 0 to 99% 1% &0.5%
Nominal SettingsNominal Settings
Nominal SettingsNominal Settings
Nominal Settings
Nominal Voltage 60 to 140 V 1 V —
Nominal Current 0.5 to 6.00 A 0.01 A —
VT Configuration Line-Line
Line-Ground
Line-Ground to Line-Line*
Seal-In Delay 2 to 8160 Cycles 1 Cycle –1 to +3 Cycles or &1%
*When line-ground to line-line is selected, the relay internally calculates the line-line voltage from the
line-ground voltages for all voltage-sensitive functions. This line-ground to line-line selection should only
be used to a VT nominal secondary voltage of 69 V (not 120 V).
78
†Select the greater of these accuracy values. Values in parentheses apply to 1 Amp CT secondary rating.
21
81R

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M-3520 Intertie Protection Relay
Configuration Options
The M-3520 Intertie Protection Relay can be purchased with standard protective functions or as a base
system with reduced functionality. The user can also select optional protective functions as required to
expand the functionality of the Standard Protection System or Base System to satisfy specific application
needs. The optional Human-Machine Interface (HMI) Module, Target Module, and redundant power supply
areavailablefor either configuration.
Metering
The relay provides metering of voltages (phase, neutral and sequence quantities), currents (phase, neutral
andsequence quantities), real power, reactive power,power factor and impedance measurements.
MeteringAccuracies are:
Voltage: ± 0.5 V or ± 0.5%, whichever is greater
&0.8 V or &0.75%, whichever is greater (when line-ground to line-line is selected)
Current: 5 A rating, ± 0.1 A or ± 3%, whichever is greater
1 A rating, ± 0.02 A or ± 3%, whichever is greater
Power ± 0.01 PU or ± 2%, whichever is greater
(realandreactive)
Frequency: ± 0.02 Hz (from 57 to 63 Hz for 60 Hz models; from 47 to 53 Hz for 50 Hz models)
Oscillographic Recorder
Theoscillograph recorder provides comprehensivedata recording of allmonitored waveforms, storing up to
170 cycles of data. The total record length may be user-configured for 1, 2, 3 or 4 partitions. The sampling
rate is 16 times the power system nominal frequency (50 or 60 Hz). The recorder is triggered either via the
designated status inputs, trip outputs, or via serial communications. When untriggered, the recorder
continuously stores waveform data, keeping the most recent data in memory. When triggered, the recorder
storespre-trigger data, then continues to store data in memory fora user-defined, post-trigger delay period.
Target Storage
A total of 32 targets can be stored. Recorded information includes the type of function(s) operated, the
functionspickedup,input/outputcontactstatus,timerstatus, and phase andneutralcurrentsat the time oftrip.
Calculations
Current and Voltage Values : Uses discrete Fourier transform algorithm on sampled (16 times per cycle)
voltage and current signals to extract fundamental frequency phasors for calculations.
Power Input Options
Nominal110/120/230/240Vac, 50/60 Hz, ornominal110/125/220/250V dc. Operates properly from 85 V ac
to 265 V ac and from 80 V dc to 288 V dc; Withstands 300 V ac or 300 V dc for 1 second; Burden 20 VA at
120 V ac/125 V dc.
Nominal 24/48 V dc. Operates properly from 18 V dc to 56 V dc; Withstands 65 V dc for 1 second; Burden
25 VA at 24 V dc and 30 VA at 48 V dc.
Unit is available with an optional redundant power supply.
Sensing Inputs
Five Voltage Inputs : Rated nominal voltage of 60 V ac to 140 V ac, 60 Hz (50 Hz optional). Withstands 240 V
continuousvoltage and360Vfor 10seconds.Sourcevoltages maybeline-to-groundor line-to-lineconnected.
Phase sequence ABC/ACB is selectable. Voltage transformer burden less than 0.2 VA at 120 V ac.
Four Current Inputs : Rated current (IR) of 5.0 A or 1.0 A (optional), 60 Hz (50 Hz optional). Withstands 2 IR
continuous current and 100 IRfor 1 second. Current transformer burden is less than 0.5 VA at 5 A (5 A
option), or 0.3 VA at 1 A (1 A option).

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M-3520 Intertie Protection Relay
Control/Status Inputs
Thecontrol/status inputs, INPUT1 through INPUT6, can be programmed toblock any of the relay functions,
triggerthe oscillographic recorder oroperate one or more outputs. The control/status inputs are designed to
be connected to dry contacts and are internally wetted with a 24 V dc power supply. To provide breaker
statusLED indication on the front panel, the INPUT1 control/statusinput contact should be connected to the
52b breaker status contact.
Output Contacts
The eight programmable output contacts (six form ‘a’ and two form ‘c’), the power supply alarm output
contact (form ‘b’), and the self-test alarm output contact (form ‘c’) are all rated as per ANSI/IEEE
C37.90-1989 for tripping: make 30 A for 0.2 seconds, carry 8 A, break 6 A @ 120 V ac, break 0.1 A @ 125
V dc, inductive break 0.1 A.
Any of the relay functions can be individually programmed to activate any one or more of the eight
programmableoutput contacts.
Target/Status Indicators and Controls
TheRELAY OK LEDrevealspropercyclingof themicrocomputer.TheBRKR CLOSED LEDilluminateswhen
thebreaker isclosed(when the52bcontact isopen).TheOSC TRIG LEDindicatesthat oscillographicdatahas
been recorded in the unit's memory. The corresponding TARGETS LED will illuminate when any of the relay
functions trip. Pressing and releasing the TARGET RESET pushbutton resets the TARGET LED if the
conditionscausing the operation have been removed. Pressing and holding the TARGET RESET pushbutton
will allow elements or funcitons in pickup to be displayed. The PS1 and PS2 LEDs remain illuminated as long
aspower is applied to the unit and the power supply isoperatingproperly.TheTIME SYNC LED will illuminate
when a valid IRIG-B signal is applied, and time synchronization has been established.
Communication
Communicationsports include rear panel RS-232andRS-485ports, a front panel RS-232port,andan IRIG-B
port. The communications protocol implements serial, byte-oriented, asynchronous communication, and
provides the following functions when used with the Microsoft®Windows™ compatible M-3822 IPScom®
CommunicationsSoftware package. MODBUS and BECO2200 protocols are supported using:
• Setpointinterrogationandmodification
• Time-stamped trip target information for the 32 most recent events
• Real time metering of all quantities measured
• Downloadingofrecorded oscillographic data (not available with MODBUSprotocol)
IRIG-B
Therelaycanaccepteithermodulated or demodulated IRIG-B time clock synchronization signal. The IRIG-B
timesynchronization information is used to correct thehour, minutes, seconds and milliseconds information.
Human-Machine Interface (HMI) Module (optional)
Local access to the relay is provided through an optional M-3931 HMI Module, allowing for easy to use,
menu-driven access to all functions via a 6-button keyboard and a 2-line by 24 character alphanumeric
display. Features of the HMI Module include the following:
• User-definable access codes providing three levels of security
• Interrogation and modification of setpoints
• Time-stamped trip target information for the 32 most recent events
• Real-timemetering of all quantities measured

–10–
M-3520 Intertie Protection Relay
Target Module (optional)
An optional M-3915 Target Module provides 24 target and 8 output LEDs. Appropriate TARGET LEDs
illuminate when the corresponding function trips. The targets can be reset with the TARGET RESET
pushbutton if the trip conditions have been removed. The OUTPUT LEDs indicate the status of the
programmable output contacts. The module connects to the M-3520 Intertie Protection unit.
Type Tests and Standards
M-3520 Intertie Protection Relay complies with the following tests and standards:
Voltage Withstand
Dielectric Withstand
IEC255-5 3,500 V dc for 1 minute applied to each independent circuit to earth
3,500 V dc for 1 minute applied between each independent circuit
1,500 V dc for 1 minute applied to IRIG-B circuit to earth
1,500 V dc for 1 minute applied between IRIG-B to each independent circuit
1,500 V dc for 1 minute applied to RS-485 circuit (2-wire) to earth
1,500 V dc for 1 minute applied to RS-485 circuit (2-wire) to each independent circuit
Impulse Voltage
IEC255-5 5,000 V pk, +/- polarity applied to each independent circuit to earth
5,000 V pk, +/- polarity applied between each independent circuit
1.2 X 50 μs, 500 Ohms impedance, three surges at 5 second intervals
Insulation Resistance
IEC255-5 > 40 MegaOhms
Electrical Environment
Electrostatic Discharge Test
IEC1000-4-2 Class 4 (8 kV) – point contact discharge
Fast Transient Disturbance Tests
IEC1000-4-4 Class 4 (4 kV, 2.5 kHz)
Surge Withstand Capability
ANSI/IEEE 2,500 V pk-pk Oscillatory applied to each independent circuit to earth
C37.90.1 2,500V pk-pk Oscillatory applied between each independentcircuit
1989 5,000 V pk Fast Transient applied to each independent circuit to earth
5,000 V pk Fast Transient applied between each independent circuit
Radiated Susceptibility
ANSI/IEEE 25–1000 MHz @ 35 V/m
C37.90.2
1987

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M-3520 Intertie Protection Relay
Output Contacts
ANSI/IEEE Make 30 A for 0.2 seconds off for 15 seconds for 2,000 operations
C37.90.0
Atmospheric Environment
Temperature
IEC68-2-1 Cold, –20° C for 96 hours
IEC6-2-2 Dry Heat, +70° C for 96 hours
IEC68-2-3 Damp Heat, +40° C @ 93% RH, for 96 hours
Mechanical Environment
Vibration
IEC255-21-1 Vibration response Class 1, 0.5 g
Vibration endurance Class 1, 1.0 g
Compliance
ULListed per 508 – Industrial Control Equipment.
CSACertifiedper C22.2 No. 14-95-Industrial Control Equipment.
External Connections
External connection points and connection information are illustrated in Figures 1, 2, and 3, on the following
pages.
Physical
Size: 19.00" wide x 5.21" high x 10.20" deep (48.3 cm x 13.2 cm x 25.9 cm)
Mounting: Theunit is a standard 19", semiflush,3-unit high, rack-mount panel design,conforming to ANSI/
EIA RS-310C and DIN 41494, Part 5 specifications. Vertical mounting is also available.
Contact Beckwith Electric for optional GE L-2/Westinghouse FT-41 retrofit panel vertical mounting details.
Approximate Weight: 17lbs (7.7 kg)
Approximate Shipping Weight: 25 lbs (11.3 kg)
Recommended Storage Parameters
Temperature: 5° C to 40° C
Humidity: Maximum relative humidity 80% for temperatures up to 31° C, decreasing to 31° C
linearly to 50% relative humidity at 40° C.
Environment: Storage area to be free of dust, corrosive gases, flammable materials, dew,
percolating water, rain and solar radiation.
See M-3520 Instruction Book, Appendix E, Layup and Storage for additional information.
Patent & Warranty
The M-3520 Intertie Protection Relay is covered by U.S. Patents 5,592,393 and 5,224,011.
The M-3520 Intertie Protection Relay is covered by a five year warranty from date of shipment.
Specification subject to change without notice.

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M-3520 Intertie Protection Relay
2345678910 2726 302928 31 32 33 34
12345678
46 47 48 49 50 51 52 53
+-
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C
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B
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A
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GC
V
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6190 118th AVE NO.
WA RNING! C ONTACT W IT H T ERM INA S MAY CAUS E E ECT RICA S HO CK
VVV
F1 F2
F3 F4
PS2 PS1
RATED CURRENT
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65
INPUTS A ARMS
(52b)
CONTACT RATINGS SEE INSTRUCTION MANUA
COM 2
BECKWITH E ECTRIC CO. INC.
RT N
RS 2 3 2
IRIG- B
+-
PS2 PS1
3AMP,250V(3AB)
5A,NOM1A , NO M
ARGO, F 33773 727- 544-2326
RX 4W
RS485
COM 3
TX
2W
VV
2
R 89464
NRT / C
IS T ED
IND.C O NT .EQ
54
IN IN IN IN IN IN
-+-+
12 13 14 15 16 17 18 19 20 232221 2524
IN
BCAB
RATED VO TAGE (NOMINA )
60- 140VAC,50/60Hz
36 43
CA
35 6359
R
83F4
R
11
18-56VDC 85-260VDC /VAC
18-56VDC 85-260VDC /VAC
45393837 40 41 42 44 55 56 57 58 60 61 62
OUTPUTS
1
Figure 1 External Connections
■■ ■■
■NOTES:
1. Output contacts #1 through #4 contain special circuitry for high-speed operation, and close 4 ms faster than outputs #5 through #8. Outputs #1
through #6 are form "a" contacts (normally open), and Outputs #7 and #8 are form "c" contacts (center tapped "a" and "b" contacts).
2. To comply with UL and CSA listing requirements, terminalblock connections must be made with #12 AWGsolid or stranded copper wire inserted in
an AMP #324915 (or equivalent) connector. Wire insulation must be rated at 60°C minimum. Terminal block connections 1 through 34 must be tightened to 12 inch-pounds torque. Terminal block connections 35 through 63 must be tightened to 8 inch-pounds torque.
3. ONLY dry contacts must be connected to inputs (terminals 5 through 10 with 11 common) because these contact inputs are internally wetted.
Application of external voltage on these inputs may result in damage to the unit.
4. All relays are shown in the de-energized state, and without power applied to the relay. 5. The power supply relay (P/S) is energized when the power supply is functioning properly. 6. The self-test relay is energized when the relay has performed all self-tests successfully.

–13–
M-3520 Intertie Protection Relay
This function is available as a
standard protective function.
This function is available as a
optional protective function.
Note: M-3520 may be purchased as a
base protection system with 59, 27,
81O/U,79 and 60FL functions only.
CT
M-3520
52
C
T
Utility
System
5252
*VT
67 51V 32 21 78 60
FL
4650
81
O/U 5959I 27 47
50
G
51
G
59
G27 G
81
R
79
25
67
N
Targets
(Optional)
Integral HMI
(Optional)
Metering
Sequence Of
Events
Waveform Capture
IRIG-B
Front RS232
Communication
Multiple Setting
Groups
Programmable I/O
Self Diagnostics
Dual Power Supply
(Optional)
Rear RS-232/485
Communication
Programmable
Logic
VT
VT
M-3520
Typical
Connection Diagram
■NOTE: *Voltage Transformer (VT) connection may be either broken delta or single, line to ground VT
dependingonapplication(forungrounded system).
Figure 2 Typical One-Line Connection Diagram
*

–14–
M-3520 Intertie Protection Relay
A
B
C
52-2
52-1
A
B
C
35 3736 38
M-3520
A
B
C
M-3520 Typical Three-line
Connection Diagram
44 43
Power
F
R
A
B
C
A
B
C
42 41
M-3520
4142 M-3520
ABC
51 50
49 48
47 46
M-3520
53 52
M-3520
40 39
VAB VBC VCA V2
36 38 4035 37 39
M-3520
44 43
V2
VAVBVC
91110 816 1361 63
M-3520
34 32
15 1260 62 33 31
IN 1
52b IN 2 IN 3 IN RTN
52b Other
Inputs
PS2 PS1
+
Self-
Test P/S OUT1
Self-
Test
Alarm
Failure
Power
OK
Status
Alarm
52-1
Trip
52a
Alarm
A
B
C
A
B
C
Alternate Phase VT
Connection
IA
IB
IC
IG
Alternate VT
Connection
Figure 3 Typical Three–Line Connection Diagram

–15–
M-3520 Intertie Protection Relay
17.31 [43.97]
ACTUAL
5.21 [13.23]
ACTUAL 5.28 [13.41]
17.50 [44.45]
10.20 [25.91]
19.00
[48.26]
17.78 [45.16]
18.58 [47.19]
2.35 [5.96]
1.35 [3.42]
Standard 19" Horizontal Mount Chassis
■NOTE: Dimensions in brackets are in centimeters.
RECOMMENDED CUTOUT WHEN RELAY IS
NOT USED AS STANDARD RACK MOUNT
Rear View
0.40 [1.02] x 0.27 [0.68] SLOT (4x)
Figure 4 Horizontal Mounting Dimensions

I
S
O
9
0
0
1
:
2
0
0
0
R
e
g
i
s
t
e
r
e
d
BECKWITH ELECTRIC CO., INC.
6190 – 118th Avenue North • Largo, Florida 33773–3724 U.S.A.
Phone [phone] • FAX [phone]
E-MAIL [email protected]
WEB PAGE www.beckwithelectric.com
© 1998 Beckwith Electric
Printed in U.S.A. 800-3520-SP-14 10-07
Optional Vertical Mount Chassis
■NOTE: Dimensions in brackets are
in centimeters.
17.78
[45.16]
18.58
[47.19]
2.25
[5.72] 1.71
[4.34]
19.00
[48.26]
17.31
[43.97]
Actual
5.59
[14.20]
5.65
[13.41]
17.50
[44.45]
ACTUAL
0.40 [1.02] x
0.27 [0.68]
SLOT (4x)
Rear View
RECOMMENDED CUTOUT WHEN RELAY IS
NOT USED AS STANDARD RACK MOUNT
Figure 5 Vertical Mounting Dimensions

WARNING
DANGEROUS VOLTAGES, capable of causing death or serious
injury, are present on the external terminals and inside the equip-
ment. Use extreme caution and follow all safety rules when han-
dling, testing or adjusting the equipment. However, these internal
voltage levels are no greater than the voltages applied to the exter-
nal terminals.
DANGER! HIGH VOLTAGE
–This sign warns that the area is connected to a dangerous high voltage, and you
must never touch it.
PERSONNEL SAFETY PRECAUTIONS
The following general rules and other specific warnings throughout the manual must be followed during application, test or repair of this
equipment. Failure to do so will violate standards for safety in the design, manufacture, and intended use of the product. Qualified
personnel should be the only ones who operate and maintain this equipment. Beckwith Electric Co., Inc. assumes no liability for the
customer’s failure to comply with these requirements.
–This sign means that you should refer to the corresponding section of the operation
manual for important information before proceeding.
Always Ground the Equipment
To avoid possible shock hazard, the chassis must be connected to an electrical ground. When servic-
ing equipment in a test area, the Protective Earth Terminal must be attached to a separate ground
securely by use of a tool, since it is not grounded by external connectors.
Do NOT operate in an explosive environment
Do not operate this equipment in the presence of flammable or explosive gases or fumes. To do so
would risk a possible fire or explosion.
Keep away from live circuits
Operating personnel must not remove the cover or expose the printed circuit board while power is
applied. In no case may components be replaced with power applied. In some instances, dangerous
voltages may exist even when power is disconnected. To avoid electrical shock, always disconnect
power and discharge circuits before working on the unit.
Exercise care during installation, operation, & maintenance procedures
The equipment described in this manual contains voltages high enough to cause serious injury or
death. Only qualified personnel should install, operate, test, and maintain this equipment. Be sure that
all personnel safety procedures are carefully followed. Exercise due care when operating or servicing
alone.
Do not modify equipment
Do not perform any unauthorized modifications on this instrument. Return of the unit to a Beckwith
Electric repair facility is preferred. If authorized modifications are to be attempted, be sure to follow
replacement procedures carefully to assure that safety features are maintained.

PRODUCT CAUTIONS
Before attempting any test, calibration, or maintenance procedure, personnel must be completely familiar
with the particular circuitry of this unit, and have an adequate understanding of field effect devices. If a
component is found to be defective, always follow replacement procedures carefully to that assure safety
features are maintained. Always replace components with those of equal or better quality as shown in the
Parts List of the Instruction Book.
Avoid static charge
This unit contains MOS circuitry, which can be damaged by improper test or rework procedures. Care
should be taken to avoid static charge on work surfaces and service personnel.
Use caution when measuring resistances
Any attempt to measure resistances between points on the printed circuit board, unless otherwise
noted in the Instruction Book, is likely to cause damage to the unit.

i
Table of Contents
Chapter 1 Introduction
1.1 Instruction Book Contents ................................................................... 1–1
1.2 M-3520Intertie Protection ................................................................... 1–2
1.3 Accessories ........................................................................................ 1–4
Chapter 2 Application
2.1 Introduction.......................................................................................... 2–1
2.2 System Diagrams ................................................................................ 2–2
2.3 Configuration ....................................................................................... 2–4
Functions ............................................................................................ 2–4
SpecialInput/OutputConsiderations ................................................... 2–4
System Setup ..................................................................................... 2–5
2.4 Setpoints and Time Settings ............................................................... 2–7
21 Phase Distance .............................................................................. 2–7
25 Sync Check ...................................................................................2–11
27Undervoltage, 3-Phase...................................................................2–16
32DirectionalPower ...........................................................................2–17
46NegativeSequenceOvercurrent ....................................................2–20
47NegativeSequenceOvervoltage....................................................2–22
50InstantaneousOvercurrent,3-Phase .............................................2–23
50GInstantaneousOvercurrent,Neutral.............................................2–24
51VInverse Time Overcurrent with
Voltage Control or Voltage Restraint ................................................ 2–25
51G Inverse Time Neutral Overcurrent ............................................ 2–28
59I Peak Overvoltage ....................................................................... 2–29
59 Overvoltage, 3-Phase .................................................................. 2–30
59G/27G Overvoltage/Undervoltage,
Neutral Circuit or Zero Sequence ..................................................... 2–31
60FL Fuse Loss ................................................................................ 2–35
67 Phase Directional Overcurrent .................................................... 2–36
67N Residual Directional Overcurrent .............................................. 2–39
78 Out of Step................................................................................... 2–41
79 Reconnect Enable Time Delay ....................................................2–43
81 Frequency.................................................................................... 2–45
81R Rate of Change of Frequency................................................... 2–47
2.5 Oscillograph Recorder ...................................................................... 2–48
2.6 TargetHistory Recorder......................................................................2–49
2.7 IRIG-BTime Synchronization .............................................................2–49
TABLE OF CONTENTS
M-3520 Intertie Protection
Instruction Book