Setting SEL-321 Relays

in the

Computer-Aided Protection Engineering System (CAPE)

Prepared for

CAPE Users’ Group

Revised October 1, 2001 Revised November 11, 2008

Electrocon International, Inc. Ann Arbor, Michigan

This document is the sole property of Electrocon International, Inc. and is provided to the CAPE Users Group for its own use only. It may not be supplied to any third party, or copied or reproduced in any form, without the express written permission of Electrocon International, Inc. All copies and reproductions shall be the property of Electrocon International, Inc. and must bear this ownership statement in its entirety.

Application Note on Setting SEL-321 Relay

I. Relay Models A. Description The CAPE library model in “cape_starter.gdb” includes the following features: • Four zones of phase and ground mho elements plus four zones of ground distance

quadrilateral elements, each reversible, with independent phase and ground timers • Positive-sequence memory voltage polarization • Four residual and negative-sequence overcurrent elements with negative-sequence

directional control • Phase, sequence, and ground time-overcurrent elements for backup protection • Negative-sequence directional element • Adaptive ground directional element choosing between negative- and zero-sequence

quantities (SEL-321-5) • Load-encroachment logic to suppress phase elements • Voltage elements The following features are not modeled specially in the SEL-321: • Single-phase elements • Single-pole tripping and phase selection (SEL-321-5) • Weak-infeed logic • Remote-end-just-opened (REJO) logic, using 50A, 50B, 50C and 3P50 IOC elements • Mirrored Bit communications-aided tripping schemes (pilot schemes can be modeled

using the CAPE AUX elements instead) • Fault Locating • SELOGIC control equations (use CAPE contact logic instead) • Power-swing blocking and tripping (but the out-of-step elements can be plotted in CAPE

CG)

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• Internal supervision of phase distance zones 1-4 by the Loss-of-Potential Logic, Single-

Pole Open Logic, and Out-of-Step Blocking Logic • Zone 1 extension • Switch-Onto-Fault Logic • Loss-of Potential and Stub Protection Logic B. Updates in the August 2001 Version You can continue to use your existing relay STYLEs, or you can replace the older STYLES with the SEL-321-1 or SEL-321-5, without losing your system settings. The database editor can compare any two STYLEs to show the taps that are different. The new STYLEs are: STYLE Rated current SEL-321-1_5A 5.0 A SEL-321-1_1A 1.0 A SEL-321-5_5A 5.0 A SEL-321-5_1A 1.0 A The newer CAPE model includes: • TIMERs set from the common taps. • 59PBD and 59PRD overvoltage timers • Separate left and right LOAD elements ZLIN and ZLOUT • Adaptive directional element for ground faults (SEL-321-5 only) • VOLT and AUX elements • Various informational taps from the current Schweitzer SEL-5010 database The following older STYLES are no longer distributed to new users in the database “cape_starter.gdb.” SEL-321-R100 5.0 A Base relay ; no timer taps SEL-321-R101 5.0 A Base relay with additional informational taps; no timer

taps SEL-321-R101_1A 1.0 A 1-Amp version of SEL-321-R101; no timer taps SEL-321-1-R101 5.0 A Older version of SEL-321-1_5A. II. Relay Elements The logic for zone 1, 2 or 3 is as follows:

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TRIPPING LOGICORPILOT SIGNAL

PHASEDISTANCE

GROUNDDISTANCE

INSTANTANEOUSOVERCURRENT

GROUND TIMEOVERCURRENT

50L

50G

32Q

50N

32Q

50Q

32Q

32Q

21G

50PP

21P32QF

50ABC

67N

51NP

67Q

51N

INSTANTANEOUSOVERCURRENT

III. Element Settings All element settings, except for contact logic, are taken from the common taps. If you change a setting or drag a curve, CAPE automatically changes the corresponding common taps. A. CT and VT Connections When you place a relay style in your system, you will have to choose an appropriate operating CT and VT. This can be done by clicking on the “Connect Op CT” button in the relay setting form of the Database Editor, and choosing a suitable CT from the list shown. If no CT exists, you will have to create one. The CT you choose will be assigned to all elements that need a current input. For the voltage input, click on the “Connect Op VT” button and choose an appropriate VT. The SEL-321 does not require a separate directional polarizing VT or polarizing CT, because CAPE stores the negative-sequence directional elements as distance elements (with ZONE_CHARAC_UNIT_1 defined as “DIRECTIONAL”). Do not change the CT and VT quantities; CAPE copies the defaults from the database library.

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B. Negative-Sequence Directional Elements 32QF and 32QR The relay measures the apparent impedance

Z Re VI

e22

2

jMTA=FHG

IKJ

−

The MTA is the tap setting Z1ANG. For forward faults, Z2 is usually negative and must be less than the tap setting Z2F. For reverse faults, Z2 is positive and must be greater than Z2R. For the optimum MTA, the positive-sequence line angle is a good approximation. CAPE models these elements as DIST elements. All settings are made from the relay common taps. You do not have to visit the individual element setting forms. You must set the common taps as follows: Z2F (Largest -seq source impedance component for forward faults) 50QF (3I2 pickup for forward faults) Z2R (Least -seq source impedance component for reverse faults) 50QR (3I2 pickup for reverse faults) a2 least unbalance I2/I1 for operation See [1] for setting rules, or use the CAPE Relay Setting macro “sel_321_nseq”. C. Distance Elements Reach and torque angle settings are made from the relay common taps. You do not have to visit the individual element setting forms. CAPE does not allow external supervision in the SEL-321. The DIST elements are already internally supervised and the present code allows only one supervisor per element. To set the DIST elements you specify the common taps, which are listed in detail below. The important settings are: • Enabling taps PMHOZ, GMHOZ and QUADZ (N,1,2,3,4). The default for these is “N”

(no operation). • A single line angle (MTA) set as Z1ANG degrees for all zones. • Zone reach (secondary ohms). For zone 1, for example, Z1P, Z1MG and XG1 are all

measured from the R-X origin to the MHO circle or QUAD reactance line in the MTA direction.

• Zero-sequence compensation taps (complex k0) for the GROUND DIST elements: k01M,

k01A for zone 1 and k0M, k0A for zones 2, 3 and 4.

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• Nonhomogeneous system compensation angle T for the ground quadrilateral element. • Pickup taps for internal overcurrent supervision: 50PP phase and 50L and 50G ground. • Negative-sequence directional elements, which supervise the distance elements except

when three-phase faults are detected. • Timer settings for phase and ground elements. The elements are: DIST “M1P” Zone 1 Phase Mho characteristic DIST “M2P” Zone 2 DIST “M3P” Zone 3 DIST “M4P” Zone 4 DIST “Z1G” Zone 1 Ground distance with Mho and Quad units DIST “Z2G” Zone 2 DIST “Z3G” Zone 3 DIST “Z4G” Zone 4 DIST “OOS” Zone 5 Out-of-step blocking element, modeled for CG only DIST “OOS” Zone 6 DIST “ZLIN” Zone 1 Left part of ZLOAD characteristic; operates only for positive-

sequence current > 0.1 * rated current and for arg(Z1) between 90 and 270 degrees (inward load)

DIST “ZLOUT” Zone 1 Right part of ZLOAD characteristic; operates only for positive-

sequence current > 0.1 * rated current and for arg(Z1) between -90 and 90 degrees (outward load)

Phase distance zones 1-4 are also supervised internally by the directional element 32QF or 32QR; these constraints are in the program code. Operation of phase distance zones 1-4 is blocked by operation of either ZLOAD element when Load-Encroachment Logic is enabled (tap ELE = ‘Y’). This constraint is in the program code. Ground distance zones 1-4 are also supervised internally by the directional element 32QF or 32QR; these constraints are in the program code. For DIST elements, you may set the Desired Primary Ohms and angle (degrees) for informational purposes only.

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D. Instantaneous Overcurrent To set the IOC elements you specify the pickups, torque control and timer settings as common taps. Also set the “Enabling” taps E50N and E50Q (N,1,2,3,4). The following supervise the distance zones: IOC “50PP1” for mho phase distance supervision IOC “50PP2” IOC “50PP3” IOC “50PP4” IOC “50L1” for phase current IOC “50L2” IOC “50L3” IOC “50L4” IOC “50G1” for residual current IOC “50G2” IOC “50G3” IOC “50G4” There are four levels of instantaneous overcurrent protection. The CAPE model treats directional and non-directional IOC elements separately; use either in the contact logic. IOC “50N1” Non-directional; instantaneous only IOC “50N2” IOC “50N3” IOC “50N4” IOC “50Q1” IOC “50Q2” IOC “50Q3” IOC “50Q4” IOC “67N1” 50N with internal supervisor DIR “32QF” or “32QR”;

instantaneous or time-delayed IOC “67N2” IOC “67N3” IOC “67N4” IOC “67Q1 ”50Q with internal supervisor DIR “32QF” or “32QR”;

instantaneous or time-delayed IOC “67Q2” IOC “67Q3” IOC “67Q4”

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Additional elements: IOC “50H” High-set phase overcurrent IOC “50M” Medium-set phase overcurrent IOC “50ABC” (+seq for out-of-step blocking) F. Phase and Ground Time Overcurrent 1. Elements To set the TOC elements you specify the curve type, pickup, time dial setting and torque-control choice as common taps. Also set the Enable taps E51N and E51Q. You do not have to visit the individual element setting forms. The elements are: TOC “51P” internal supervisor tap-selectable (M2P, ZLIN, ZLOUT,

None) TOC “51N” internal supervisor tap-selectable (32QF, 32QR, Z2G, None) TOC “51Q” internal supervisor tap-selectable (32QF, 32QR, M2P, Z2G,

None) The alternative time-overcurrent curves are [1]: CHARACTERISTIC CAPE database name Common Tap Setting U1: Moderately Inverse US_MOD_INVERSE_501 U1 U2: Inverse U.S. Inverse U2 U3: Very Inverse U.S. Very Inverse U3 U4: Extremely Inverse U.S. Extrem. Inverse U4 C1: Standard Inverse IEC_A_STANDARD_INV C1 C2: Very Inverse IEC_B_VERY_INVERSE C2 C3: Extremely Inverse IEC_C_EXTREM_INVERSE C3 C4: Long Time Backup IEC_LONG_TIME_INV C4 CAPE uses a fixed dropout time of 1 cycle; the reset equation is not implemented. The time-dial Common Tap ranges are 0.01 - 15 with step 0.01 for all STYLES, to cover the ranges of both US curves (0.5 to 15) and IEC curves (0.01 to 1.0). Phase TOC elements may be blocked by one of the forward or reverse load-encroachment elements (ZLOUT or ZLIN), or may be supervised by the Zone 2 element M2P. These options are included in the library model.

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2. Increasing the TOC operating time for high currents The SEL-321 has three IOC elements to provide logical outputs for the TOC pickups with no time delay: 51NP, 51QP and 51PP. These have the same torque-control taps as the TOC elements 51N, 51Q and 51P. You may use these to provide a minimum operating time after the TOC element picks up. For the ground TOC element 51N, for example, choose 51NP to supervise an AUX element TX set with the required tripping delay. Use 51N and TX as the contact logic codes for elements 51N and TX. Then set a contact logic expression for the LZOP to include terms (51N AND TX). G. Timers You set all TIMERs using the common taps. (Earlier versions of the SEL-321 library used the TIMER element setting form instead.) For each timer that you intend to include in the trip logic, set a suitable CONTACT_LOGIC_CODE. For instantaneous tripping of a zone, give its TIMER tap an operating time of zero. The phase and ground elements have separate timers, as follows: TIMER “Z2PD” internal supervisor DIST “M2P” Zone 2 TIMER “Z3PD” internal supervisor DIST “M3P” Zone 3 TIMER “Z4PD” internal supervisor DIST “M4P” Zone 4 TIMER “Z2GD” internal supervisor DIST “Z2G” Zone 2 TIMER “Z3GD” internal supervisor DIST “Z3G” Zone 3 TIMER “Z4GD” internal supervisor DIST “Z4G” Zone 4 TIMER “67NL1D” internal supervisor IOC “67N1” TIMER “67NL2D” internal supervisor IOC “67N2” TIMER “67NL3D” internal supervisor IOC “67N3” TIMER “67NL4D” internal supervisor IOC “67N4” TIMER “67QL1D” internal supervisor IOC “67Q1” TIMER “67QL2D” internal supervisor IOC “67Q2” TIMER “67QL3D” internal supervisor IOC “67Q3” TIMER “67QL4D” internal supervisor IOC “67Q4” TIMER “50PBD” internal supervisor VOLT “59PB” TIMER “50PRD” internal supervisor VOLT “59PR”

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The three timers TX, TY and TZ are stored as AUX elements; CAPE automtically sets their pickup and dropout times from the common taps. Other timers are provided for record-keeping only. It is unlikely that they will be included in the LZOP trip path. H. Voltage Elements 27L Phase undervoltage (Min (Va, Vb, Vc)) 3P27 Three-phase undervoltage (Max (Va, Vb, Vc)) 3P59 Three-phase overvoltage (Min (Va, Vb, Vc)) 59L Phase overvoltage (Max (Va, Vb, Vc)) 59N Zero-sequence overvoltage (3V0) 59PB + seq bus overvoltage (Vp) with timer 50PBD Voltage element 59PR, if modeled fully, would need to be a DIST element in CAPE as it operates on both current and voltage. It estimates a remote-bus overvoltage for long lines as (Vo - a1 * Z1L * Ip). The element is not normally used in distance or pilot protection schemes. The CAPE model uses Vp only and treats tap “a1” as zero. I. AUX Elements The following AUX elements may be used in the system data with any supervising elements. You must specify the supervisors separately in the system Aux Element Data form for each SEL-321 relay in the system. The pickup and dropout times are read from the common taps specified in the library data. Element Pickup_Time_Tap_Name Dropout_Time_Tap_Name TX TXPU TXDO TY TYPU TYDO TZ TZPU TZDO IV. Distance Element Comparators Let the (+/-/0) sequence relay voltages and currents be (V1, V2, V0) and (I1, I2, I0). Let the phase A, B and C voltages and currents be (Va, Vb, Vc) and (Ia, Ib, Ic). A. Negative-Sequence Directional Elements The relay measures the apparent impedance

9

22

2

VZ = exp(-j MTA)I

⎛ ⎞⎜ ⎟⎝ ⎠

The MTA is the tap setting Z1ANG. For forward faults, Z2 is usually negative and must be less than the tap setting Z2F. For reverse faults, Z2 is positive and must be greater than Z2R. For the optimum MTA, the line angle Z1ANG is a good approximation. Abs(I2/I1) must exceed the setting “a2”, and abs (3*I2) must exceed the pickup 50QF (forward) or 50RF (reverse). B. Supervision of Distance Zones The phase A ground elements will operate only if abs(Ia) > pickup 50L for the zone and abs(3 * I0 > pickup 50G for the zone Each ground distance element is supervised by the negative-sequence directional element, directly in the program code. The B-C phase (MHO) element will operate only if abs(Ib-Ic) > pickup 50AB for the zone. If fewer than three DIST phase loops operate, the phase element is also supervised by the negative-sequence directional element, directly in the program code. If all three phase loops operate, the phase element operation is restricted by the ZLOAD limit as in [1]. C. MHO and QUAD Elements All three phase-phase or phase-ground loops are evaluated; the element asserts if any one phase asserts. In the phase distance elements, a memory-polarized mho comparator evaluates the three phase-phase loops “A-B,” “B-C” and “C-A.” The zone will operate if any one of the three loops operates according to the following equation (shown for loop “A-B”):

Re V conj V

Re e I conj VZAB AB,MEM

jMTAAB AB,MEM

REACH⋅

⋅ ⋅<

c hc h

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VAB and IAB are the voltage and current in the loop. The “MEM” subscript denotes memory (prefault) voltage in the loop. MTA is the tap setting Z1ANG. ZREACH is the reach of the zone being evaluated (the circle diameter and the magnitude in the MTA direction). The other two loops are evaluated similarly. The Operating CT Quantity and Operating VT Quantity are set internally in the code as “Three Phase” (A or B or C). For the ground distance elements, both the MHO element and the reactance portion of the quadrilateral element compare the reach with its tap setting (e.g. Z1P, Z1MG, X1G) at the line angle Z1ANG, not at 90 degrees. The quadrilateral element sees fault resistance up to the tap setting (e.g. RG1) for a radial line. For a non-radial line, the remote-end infeed reduces the resistive reach. The ground distance comparator equations are quoted below from reference [2] for mho, reactance, and resistance boundaries. The negative-sequence directional element determines the boundary behind the relay.

Excerpt from [2] showing ground mho comparator equations for SEL-321 distance elements. k0 is the zero-sequence compensation setting (Z0L/Z1L –1)/3 for the protected line. Ir = 3 I0 = residual current into the protected line.

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Excerpt from [2] showing ground quad comparator equations for SEL-321 distance elements. The "S-bus" is the local bus at the relay. k0 and T are relay settings.

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The ground quadrilateral element is bounded at the top by the reactance line. The tilt angle T is set nonzero for a nonhomogeneous system (where the zero-sequence source impedance angles at the line ends are different from the line angle). T should be estimated for a single-line-ground fault as: T = arg(fault current from line to ground) - arg (zero-sequence current from relay to fault). T is a function of fault location and the network impedances. It is independent of load. If T is set exactly, the reach is independent of load. If T varies along the line, T should be set at its value for a fault on the line-end bus, negative or zero but not positive. A negative value of T tilts the reactance line down to the right. Then any error in T causes underreach rather than overreach, increasing security. When you apply a fault and plot it in Coordination Graphics, the apparent impedance that is reported and displayed (for the ground distance element) depends on the type of unit that is enabled in the relay. If both the MHO and QUAD units are enabled, then, the apparent impedance is the ground-current compensated value given by

AAPP

A 0

VZI 3I K

=0+ ⋅

The above value is shown and reported irrespective of which of the two units operated. If the QUAD unit is the only one enabled, the apparent impedance is not a single calculation. It is made up of two parts: (a) the calculation of the reactance according to equation 18 above (excerpt from [2]), and (b) the calculation of the fault resistance RF according to equation 20 above (excerpt from [2]). It is important to note that equation 18 is not a true reactance measurement, but measurement along the angle Z1ANG. Also, RF is the estimate of the fault resistance component, and does not include the resistance of the protected line to the point of fault. Therefore, the calculated apparent impedance must be manipulated a little bit before it can be plotted in CG, and reported. D. Fault Identification Selection (FIDS) Logic [3] This identifies the faulted phases in ground faults. If the ground current (3I0) is greater than 0.1 * rated current, the phase and ground distance elements are blocked for selected phases. Otherwise, any phase can cause tripping. Let I0 and Ia2 be the relay zero-sequence and negative-sequence currents (the phase A sequence components).

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Let arg (Ia2/I0) = S, when both 3*Ia2 and 3*I0 magnitudes exceed 0.1 * rated current. If -30 <= S <= 30 degrees, the fault is A-G or B-C-G and is measured by elements A-G and B-C only. The remaining elements are blocked. If -30 <= arg (Ib2/I0) <= 30 degrees, the fault is B-G or C-A-G and is measured by elements B-G and C-A only. Here Ib2 is the phase B component of negative sequence current: b2 a2arg (I ) = arg (I ) + 120degrees, so the phase B condition is equivalently -150 <= S <= -90 degrees. Similarly, a C-G or A-B-G fault is detected when 90 <= S <= 150 degrees. The margin of 30 degrees is arbitrarily suggested in [3] because most faults have an angle S close to one of the center values (0, 120, -120). If S differs by more than 30 degrees from all the center values, there is no phase selection in CAPE and any element can operate. The additional rules for the actual relay are not available. V. Contact Logic To assign contact logic, first enter the element data for the system. In the database editor, select the Elements tab of the Protective Device Data form. You specify a contact logic code for each element that directly trips the breakers in the relay LZOP. All other contact logic codes can be blank. In the simplest schemes, only the TOC element, the ZONE 2-4 TIMERS, and the ZONE 1 DISTANCE elements need contact-logic codes. Next go to the Contact Logic Data form and enter the contact logic codes and expressions. You can enter the tripping code as a single long expression or in several stages. Finally view the LZOP Data form and assign the highest-level LZOP logic code. When this asserts as TRUE, the breakers in the LZOP open. The DIST, IOC and TOC elements can be taken out of service by setting their “Enable” taps appropriately (N, 1, 2, 3, 4), or by setting their CONTACT_STATUS to ‘O’. The contact-logic-code names will help you to interpret the reports from CAPE RC and SS. The names of the SELogic variables are suitable. Since each contact logic code can refer to at most one element in the LZOP, you should add a prefix if there are two similar relays in the LZOP.

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The following are examples. Element Suggested Contact Logic TOC “51N” Neutral 51N (or A_51N, B_51N to keep names

unique in A and B schemes) TOC “51P” Three-phase 51P TOC “51Q” Negative-Sequence (3*INR) 51Q For DIST elements the Contact Logic Code is usually blank except for Zone 1. Suggested values for Zone 1 Contact Logic are: DIST “M1P” M1P DIST “Z1G” Z1G If you want to use the elements 50PP, 50L, or 50G in your trip logic, you can define the following intermediate contact logic codes in the Contact Logic Data. 50PP = 50PP1 or 50PP2 or 50PP3 or 50PP4 50L = 50L1 or 50L2 or 50L3 or 50L4 50G = 50G1 or 50G2 or 50G3 or 50G4 Example of Contact Logic Data: SEL321_TRIP (DIST OR TOC) SEL321_TOC (51P OR 51Q OR 51N) SEL321_DIST (SEL321_Z1 OR SEL321_T2 OR SEL321_T3 OR SEL321_T4) SEL321_Z1 (M1P OR Z1G) SEL321_T2 (Z2PD OR Z2GD) SEL321_T3 (Z3PD OR Z3GD) SEL321_T4 (Z4PD OR Z4GD) VI. Common Taps Only the taps that CAPE uses are shown here. All the taps are shown in the database editor. They may be set for recordkeeping by the user. All taps are set in secondary (relay) units (amps, volts or ohms). All angles are in degrees. All times are in cycles.

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Line Settings Z1MAG Positive_Seq. Line Impedance Magnitude Z1ANG Positive-Seq. Line Impedance Angle Z0MAG Information only (Zero-Seq. Line Impedance Magnitude) Z0ANG Information only (Zero-Seq. Line Impedance Angle) LL Information only (Line Length) CTR Information only (Current Transformer Ratio) PTR Information only (Potential Transformer Ratio) Enable Zones of Distance Settings (N = none, 1 = zone 1 only; 2= zones 1 and 2, etc.) PMHOZ Mho Phase enable(N,1,2,3,4) GMHOZ Mho Ground enable QUADZ Quad Ground enable Distance-Zone and Overcurrent-Level Direction DIR1 Distance Zone 1/Overcurrent Level 1 Direction (F/R) DIR2 Distance Zone 2/Overcurrent Level 2 Direction DIR3 Distance Zone 3/Overcurrent Level 3 Direction DIR4 Distance Zone 4/Overcurrent Level 4 Direction Mho Phase Distance Z1P Zone 1 Phase Reach at angle Z1ANG Z2P Zone 2 Phase Reach at angle Z1ANG Z3P Zone 3 Phase Reach at angle Z1ANG Z4P Zone 4 Phase Reach at angle Z1ANG Mho Phase Distance Overcurrent Supervision 50PP1 Zone 1 Phase supervising IOC pickup (A) 50PP2 Zone 2 Phase supervising IOC pickup (A) 50PP3 Zone 3 Phase supervising IOC pickup (A) 50PP4 Zone 4 Phase supervising IOC pickup (A) Mho Ground Distance Z1MG Zone 1 Ground MHO Reach at angle Z1ANG Z2MG Zone 2 Ground MHO Reach at angle Z1ANG Z3MG Zone 3 Ground MHO Reach at angle Z1ANG Z4MG Zone 4 Ground MHO Reach at angle Z1ANG Quadrilateral Ground Distance XG1 Zone 1 Ground QUAD Reach at Z1ANG XG2 Zone 2 Ground QUAD Reach at Z1ANG

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XG3 Zone 3 Ground QUAD Reach at Z1ANG XG4 Zone 4 Ground QUAD Reach at Z1ANG RG1 Zone 1 Ground QUAD Resistive Reach RG2 Zone 2 Ground QUAD Resistive Reach RG3 Zone 3 Ground QUAD Resistive Reach RG4 Zone 4 Ground QUAD Resistive Reach Ground Distance Overcurrent Supervision 50L1 Zone 1 Ground supervising phase IOC pickup 50L2 Zone 2 Ground supervising phase IOC pickup 50L3 Zone 3 Ground supervising phase IOC pickup 50L4 Zone 4 Ground supervising phase IOC pickup 50G1 Zone 1 Ground supervising residual IOC pickup (3I0) 50G2 Zone 2 Ground supervising residual IOC pickup (3I0) 50G3 Zone 3 Ground supervising residual IOC pickup (3I0) 50G4 Zone 4 Ground supervising residual IOC pickup (3I0) Zero-Sequence Compensation Factor k01M Zone 1 Zero-Sequence Comp. Magnitude (Z0/Z1 - 1)/3 k01A Zone 1 Zero-Sequence Comp. Angle k0M Zone 2, 3, & 4 Zero-Sequence Comp. Magnitude k0A Zone 2, 3, & 4 Zero-Sequence Comp. Angle T Non-Homogeneous Correction Angle (for Ground QUAD) Out-of-Step Blocking and Tripping X1T5 Zone 5 OOS Top Reactive Reach X1B5 Zone 5 OOS Bottom Reactive Reach R1R5 Zone 5 OOS Right Resistive Reach R1L5 Zone 5 OOS Left Resistive Reach X1T6 Zone 6 OOS Top Reactive Reach X1B6 Zone 6 OOS Bottom Reactive Reach R1R6 Zone 6 OOS Right Resistive Reach R1L6 Zone 6 OOS Left Resistive Reach 50ABC Zone 6 Positive-sequence overcurrent supervision Load Encroachment ELE Enable Load-Encroachment (Y/N) ZLF Load-Encroachment Forward Reach ZLR Load-Encroachment Reverse Reach PLAF Load-Encroachment Forward Positive Angle NLAF Load-Encroachment Forward Negative Angle

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PLAR Load-Encroachment Reverse Positive Angle NLAR Load-Encroachment Reverse Negative Angle Negative Sequence Directional Element Z2F Forward Directional Z2 Threshold (ohms) 50QF Forward Directional Current Threshold (A) Z2R Reverse Directional Z2 Threshold (ohms) 50QR Reverse Directional Current Threshold (A) a2 Positive-Sequence Current Restraint Factor (I2/I1) Phase Time-Overcurrent Element E51P Enable Phase TOC (Y/N) 51PP Phase TOC pickup 51PC Phase TOC Curve Family 51PTD Phase TOC Time-Dial 51PRS Information only (Phase TOC Reset Delay) 51PTC Phase TOC Torque Control (ZLIN,ZLOUT,M2P,N) Residual Time-Overcurrent Element E51N Enable Residual TOC (Y/N/S with S treated as Y) 51NP Residual TOC pickup (3I0) 51NC Residual TOC Curve Family 51NTD Residual TOC Time-Dial 51NRS Information only (Residual TOC Reset Delay) 51NTC Residual TOC Torque Control (32QF,32QR,Z2G,N) Residual Overcurrent Element E50N Enable Number of Residual IOC Levels (N,1,2,3,4) 50N1 Level 1 Residual IOC pickup (3I0) 50N2 Level 2 Residual IOC pickup 50N3 Level 3 Residual IOC pickup 50N4 Level 4 Residual IOC pickup Negative-Sequence Time-Overcurrent Element E51Q Enable Negative-Sequence TOC (Y/N/S with S treated as Y) 51QP Negative-Sequence TOC pickup (3I2) 51QC Negative-Sequence TOC Curve Family 51QTD Negative-Sequence TOC Time-Dial 51QRS Information only (Negative-Sequence TOC Reset Delay) Y/N 51QTC Negative-Sequence TOC Torque Control

(32QF,32QR,M2P,Z2G,N)

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Negative-Sequence Overcurrent Element E50N Enable Number of Negative-Sequence IOC Levels (N,1,2,3,4) 50N1 Level 1 Negative-Sequence IOC pickup 50N2 Level 2 Negative-Sequence IOC pickup 50N3 Level 3 Negative-Sequence IOC pickup 50N4 Level 4 Negative-Sequence IOC pickup Voltage Element EVOLT Enable Voltage Elements 59N Zero-Sequence Over-Voltage 27L Bus Phase Under-Voltage 59L Bus Phase Over-Voltage 59PB Positive-Sequence bus over-voltage pickup 59PBD Positive-Sequence bus over-voltage delay 59PR Positive-Sequence remote bus over-voltage 59PRD Current-compensated remote over-voltage time delay a1 Information only: current-compensated remote voltage

adjustment Time Step Backup Time Delay Z2PD Zone 2 phase long time delay (cycles) Z3PD Zone 3 phase time delay Z4PD Zone 4 phase time delay Z2GD Zone 2 ground long time delay Z3GD Zone 3 ground time delay Z4GD Zone 4 ground time delay 67NL1D Level 1 residual delay 67NL2D Level 2 residual delay 67NL3D Level 3 residual delay 67NL4D Level 4 residual delay 67QL1D Level 1 neg-seq delay 67QL2D Level 2 neg-seq delay 67QL3D Level 3 neg-seq delay 67QL4D Level 4 neg-seq delay Permissive Overreach: settings used for information only Directional Comparison Unblocking: for information only Directional Comparison Blocking: for information only Zone 1 Extension: for information only Remote-End-Just-Opened: for information only Switch-Onto-Fault: for information only

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Loss-of-Potential: for information only Miscellaneous Schemes: for information only Miscellaneous Timers TXPU AUX element TX pickup delay TXDO AUX element TX dropout delay TYPU AUX element TY pickup delay TYDO AUX element TY dropout delay TZPU AUX element TZ pickup delay TZDO AUX element TZ dropout delay Logic: for information only Special taps for CAPE model (setting fixed for each STYLE) ADAPTIVE_GROUND_DIR Y for adaptive torque control; in SEL-321-5 only RATED_CURRENT 1A or 5A References 1. “SEL-321, SEL-321-1, and SEL 321-2 Phase and Ground Distance Relay, Directional

Overcurrent Relay, and Fault Locator Instruction Manual,” Schweitzer Engineering Laboratories, Inc., Pullman WA; November 20, 1996.

2. S. E. Zocholl, “Three-Phase Circuit Analysis and the Mysterious k0 Factor,” 22nd

Annual Western Protective Relay Conference, Spokane, Washington; October 1995. 3. E. O. Schweitzer III and Jeff Roberts, “Distance Relay Element Design,” 46th Annual

Conference for Protective Relay Engineers, Texas A & M University, College Station, Texas; April 12-14, 1993.

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