Schweitzer Engineering Laboratories SEL-787-3 User manual

Schweitzer Engineering Laboratories, Inc. SEL-787-3, -4 Data Sheet

Major Features and Benefits

The SEL-787 Transformer Protection Relay provides unsurpassed protection, integration, and control features in a

flexible, compact, and cost-effective package. The SEL-787 offers an extensive variety of protection features, depending

on the model and options selected. In this document, SEL-787 refers to all the models in Table 1. For protection func-

tions specific to a given MOT, the relay is referred to as SEL-787-4X, SEL-787-3E, or SEL-787-3S explicitly, where

needed. Model options SEL-787-4X, SEL-787-3E, and SEL-787-3S are all considered base models. Table 2 shows the

protection features available across different models.

SEL-787-3E Model SEL-787-3S Model SEL-787-4X Model

Table 1 Current (ACI) and Voltage (AVI) Card Selection for SEL-787 Models

Model Description/Application Slot Z Card

(MOT Digits) Slot Z Inputs Slot E Card

(MOT Digits) Slot E Inputs

787-4X 4 Winding/Terminal Current Differential 6 ACI

(81, 82, 85)

IAW1, IBW1, ICW1,

IAW2, IBW2, ICW2

6ACI

(A1, A2, A5)

IAW3, IBW3, ICW3,

IAW4, IBW4, ICW4

787-3E 3 Winding/Terminal Current Differential

1 Neutral Current Input

3 Voltage Inputs (Phase)

6ACI

(81, 82, 85)

IAW1, IBW1, ICW1,

IAW2, IBW2, ICW2

4ACI/3AVI

(72, 73, 76, 77)

IAW3, IBW3, ICW3,

IN, VA, VB, VC

787-3S 3 Winding/Terminal Current Differential

3 Voltage Inputs (Phase)

1 Voltage Input (Vsync or Vbat)

6ACI

(81, 82, 85)

IAW1, IBW1, ICW1,

IAW2, IBW2, ICW2

3ACI/4AVI

(71, 75)

IAW3, IBW3, ICW3,

VS/VBAT, VA, VB,

SEL-787-3, -4 Transformer Protection

Relay

SEL-787-3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.

Table 2 Protection Element Table

Protection Elements

4 Windings

3 Windings With IN

Channel and 3-Phase

Voltages

3 Windings With

VS/VBAT Channel and

3-Phase Voltages

SEL-787-4X SEL-787-3E SEL-787-3S

87 Phase Differential X X X

REF Restricted Earth Fault XaXaXa

50P Phase Overcurrent X X X

50Q Neg.-Seq. Overcurrent XXX

50G Ground Overcurrent X X X

50N Neutral Overcurrent X

51P Phase Time-Overcurrent X X X

51Q Neg.-Seq. Time-Overcurrent XXX

51G Ground Time-Overcurrent X X X

51PC Combined Winding Phase Time-

Overcurrent XXX

51GC Combined Winding Ground Time-

Overcurrent XXX

51N Neutral Time-Overcurrent X

27P Phase Undervoltage X X

27PP Phase-to-Phase Undervoltage X X

27S VS Channel Undervoltage X

59P Phase Overvoltage X X

59PP Phase-to-Phase Overvoltage X X

59Q Neg.-Seq. Overvoltage X X

59G Ground Overvoltage X X

59S VS Channel Overvoltage X

24 Volts/Hz X X

25 Synchronism Check X

32 Directional Power X X

49RTD RTDs XXX

60LOP Loss of Potential X X

81 Over- and Underfrequency X X

BF Breaker Failure X X X

aRefer to Table 3 for the available REF elements based on the configuration of Winding 3.

Table 3 Available Differential and REF Elements Based on the Configuration of Winding 3

Elements SEL-787-3E SEL-787-3S SEL-787-4X

Differential Protection Windings (Standard) 3 3 4

REF Elements (Standard) 1 0 0

Differential Protection Windings

(Winding 3 Configured for REF)

223

REF Elements

(Winding 3 Configured for REF)

322

Schweitzer Engineering Laboratories, Inc. SEL-787-3, -4 Data Sheet

➤Standard Protection Features. Make use of standard dual-slope differential protection with harmonic blocking and

restraint for as many as four windings and as many as three independent restricted earth fault (REF) elements for

sensitive ground-fault detection in grounded wye-transformers. The SEL-787 Transformer Protection Relay allows

configuration of Winding 3 for either differential or REF protection. Refer to Table 3 for the available REF elements

based on the configuration of Winding 3. The relay also includes phase, negative-sequence, residual ground, and

neutral-ground overcurrent elements for backup protection. Breaker failure protection for as many as four three-pole

breakers also comes standard.

➤Additional Protection Features. Take advantage of SEL-787-3E/S volts/hertz protection with frequency tracking

from 15 to 70 Hz for generator step-up and variable frequency applications. Use over- and underfrequency and over-

and undervoltage elements to implement load shedding and other control schemes on the relay.

➤Synchronism Check/Station DC Battery Monitor. Program the VS/VBAT voltage channel in the SEL-787-3S

model to perform a synchronism check across a circuit breaker or to monitor dc voltage levels of the substation

battery.

➤Transformer Monitoring. Measure accumulated through-fault levels with the transformer through-fault monitor.

Additionally, use the optional 4–20 mA or RTD thermal inputs to monitor ambient, load tap-changer (LTC) tank,

and transformer oil temperature.

➤Operator Controls. Take advantage of eight programmable front-panel pushbuttons, each with two programmable

tricolor LEDs, for various uses, such as easy trip and close control and status indication for all the breakers. Use the

operator control interface pushbuttons to easily implement local and remote operator control schemes using 32 local

and 32 remote control bits. Use SELOGIC®control equations and slide-in, configurable front-panel labels to change

the function and identification of target LEDs and operator control pushbuttons and LEDs.

➤Relay and Logic Settings Software. Use ACSELERATOR QuickSet®SEL-5030 Software to reduce engineering costs

related to relay settings and logic programming and to simplify development of SELOGIC control equations. Verify

proper CT polarity and phasing through use of the built-in phasor display.

➤Metering and Reporting. Use built-in metering functions that eliminate separately mounted metering devices.

Analyze Sequential Events Recorder (SER) reports and oscillographic event reports for rapid commissioning,

testing, and post-fault diagnostics. Unsolicited SER protocol allows station-wide collection of binary SER messages.

➤Additional Standard Features. Further enhance your power system protection by taking advantage of several other

SEL-787 standard features in communication, monitoring, and support. Modbus®RTU, Event Messenger support,

MIRRORED BITS®communications, as well as load profile and breaker wear monitoring all come standard with the

SEL-787. The relay also supports 12 additional external RTDs (SEL-2600 series module), IRIG-B input, advanced

SELOGIC control equations, IEEE®C.37.118-compliant synchrophasor protocol, and an SEL-2812 compatible ST®

fiber-optic serial port.

➤Optional Features. Communicate with a number of additional optional communications protocols and ports,

digital/analog I/O, and RTDs. Optional communications protocols include IEC 61850, Modbus®TCP/IP, Simple

Network Time Protocol (SNTP), DNP3 LAN/WAN, DNP3 serial, and IEC 60870-5-103. Elective communications

ports include EIA-232 or EIA-485, and single or dual, copper or fiber-optic Ethernet ports. Several digital/analog

I/O options are available. These include 4 AI/4 AO, 4 DI/4 DO, 8 DI, 8 DO, 3 DI/4 DO/1 AO, and 4 DI/3 DO. An

optional 10 internal RTD card is also available for the SEL-787 relay.

➤Language Support. Choose English or Spanish for your serial ports, including the front-panel serial port. The

standard relay front-panel overlay is in English; a Spanish overlay is available as an ordering option.

SEL-787-3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.

Functional Overview

Figure 1 SEL-787-3E Functional Diagram

Temperature Alarm

and Trip

SEL-787-3E Transformer Protection Relay

Overcurrent Time-Overcurrent

Combined

Time-

Overcurrent

Overcurrent Time-Overcurrent

• Sequential Events Recorder

• Event Reports

• SEL ASCII, Ethernet*, Modbus TCP*, IEC 61850*, DNP3

LAN/WAN*, DNP3 Serial*, 60870-5-103*, Modbus RTU,

Telnet, FTP, SNTP*, and DeviceNet

Communications*

• Synchrophasor Data and IEEE C37.118 Compliant Protocol

• Front-Panel Programmable Tricolor LED Targets

• Two Inputs and Three Outputs Standard

• I/O Expansion*--Additional Contact Inputs, Contact

Outputs, Analog Inputs, Analog Outputs, and RTD Inputs

• Single or Dual Ethernet Copper or Fiber-Optic

Communications Port*

Σ5151 P

8787

Overcurrent Time-Overcurrent

3232

2424 8181 O

Volts/Hertz Frequency

LOPLOP

27P27P 5959

Restricted Earth

Fault (REF)

Directional

Power

Loss of Potential

Undervoltage Overvoltage

Current

Differential

• Battery-Backed Clock, IRIG-B Time Synchronization

• Instantaneous, Differential, Harmonic, and RMS

Metering

• Programmable Pushbuttons and LED Indicators

• Through-Fault Monitoring

• Transformer Thermal Monitoring

• Circuit Breaker Contact Wear Monitor

• Advanced SELOGIC Control Equations

• 32 Programmable Display Messages

• MIRRORED BITS Communications

*Optional Functions

Internal or External

RTD Input

Schweitzer Engineering Laboratories, Inc. SEL-787-3, -4 Data Sheet

Figure 2 SEL-787-3S Functional Diagram

Temperature Alarm

and Trip

SEL-787-3S Transformer Protection Relay

Overcurrent Time-Overcurrent

Combined

Time-

Overcurrent

Overcurrent Time-Overcurrent

• Sequential Events Recorder

• Event Reports

• SEL ASCII, Ethernet*, Modbus TCP*, IEC 61850*, DNP3

LAN/WAN*, DNP3 Serial*, 60870-5-103*, Modbus RTU,

Telnet, FTP, SNTP*, and DeviceNet

Communications*

• Synchrophasor Data and IEEE C37.118 Compliant Protocol

• Front-Panel Programmable Tricolor LED Targets

• Two Inputs and Three Outputs Standard

• I/O Expansion*--Additional Contact Inputs, Contact

Outputs, Analog Inputs, Analog Outputs, and RTD Inputs

• Single or Dual Ethernet Copper or Fiber-Optic

Communications Port*

Σ5151 P

8787

Overcurrent Time-Overcurrent

Undervoltage Overvoltage

3232

2424 8181 O

Volts/Hertz Frequency

LOPLOP

27P27P 5959

Synch Check

Directional

Power

Loss of Potential

Undervoltage Overvoltage

Current

Differential

• Battery-Backed Clock, IRIG-B Time Synchronization

• Instantaneous, Differential, Harmonic, and RMS

Metering

• Programmable Pushbuttons and LED Indicators

• Through-Fault Monitoring

• Transformer Thermal Monitoring

• Circuit Breaker Contact Wear Monitor

• Advanced SELOGIC Control Equations

• 32 Programmable Display Messages

• MIRRORED BITS Communications

*Optional Functions

Internal or External

RTD Input

2525

27S27S 59S59S

SEL-787-3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.

Figure 3 SEL-787-4X Functional Diagram

Temperature Alarm

and Trip

SEL-787-4X Transformer Protection Relay

Overcurrent Time-Overcurrent

Combined

Time-

Overcurrent

Overcurrent Time-Overcurrent

• Sequential Events Recorder

• Event Reports

• SEL ASCII, Ethernet*, Modbus TCP*, IEC 61850*, DNP3

LAN/WAN*, DNP3 Serial*, 60870-5-103*, Modbus RTU,

Telnet, FTP, SNTP*, and DeviceNet

Communications*

• Synchrophasor Data and IEEE C37.118 Compliant Protocol

• Front-Panel Programmable Tricolor LED Targets

• Two Inputs and Three Outputs Standard

• I/O Expansion*--Additional Contact Inputs, Contact

Outputs, Analog Inputs, Analog Outputs, and RTD Inputs

• Single or Dual Ethernet Copper or Fiber-Optic

Communications Port*

Σ51

Current

Differential

• Battery-Backed Clock, IRIG-B Time Synchronization

• Instantaneous, Differential, Harmonic, and RMS

Metering

• Programmable Pushbuttons and LED Indicators

• Through-Fault Monitoring

• Transformer Thermal Monitoring

• Circuit Breaker Contact Wear Monitor

• Advanced SELOGIC Control Equations

• 32 Programmable Display Messages

• MIRRORED BITS Communications

*Optional Functions

Internal or External

RTD Input

Overcurrent Time-Overcurrent

Combined

Time-

Overcurrent

Overcurrent Time-Overcurrent

Σ51

Schweitzer Engineering Laboratories, Inc. SEL-787-3, -4 Data Sheet

Protection Features

The SEL-787 Relay offers dual-slope differential charac-

teristic for transformer differential protection. The

SEL-787 includes a complete set of phase, negative-

sequence, and residual overcurrent elements for each ter-

minal (winding), as well as REF and neutral-overcurrent

elements for grounded wye transformers.

Use as many as 12 independent RTD-driven thermal

elements with trip and alarm levels to monitor ambient

and equipment temperatures throughout the substation.

For the optional volts/hertz element, you can add three-

phase voltage inputs that give the SEL-787 volts/hertz

protection with definite-time and time-delay

characteristics, along with directional power, over- and

underfrequency, and over- and undervoltage elements with

two independent pickup levels and time delay.

Transformer Differential

The SEL-787 has three restrained differential elements

(87R). These elements use operate and restraint quanti-

ties calculated from as many as four winding input cur-

rents. Set the differential elements with either single- or

dual-slope percentage differential characteristics.

Figure 4 illustrates a dual-slope setting. The percent-

slope characteristic helps prevent undesired relay opera-

tion because of a possible unbalance between CTs during

external faults. CT unbalance can result from TAP

changing in the power transformer and error difference

between the CTs on either side of a power transformer.

Figure 4 Dual-Slope Restrained Differential

Characteristic

With the SEL-787, you can choose harmonic blocking,

harmonic restraint, or both, to provide reliable

differential protection during transformer inrush

conditions. Even-numbered harmonics (second and

fourth) provide security during energization, while fifth-

harmonic blocking provides security for overexcitation

conditions. Set second-, fourth-, and fifth-harmonic

thresholds independently.

An additional alarm function for the fifth-harmonic

current employs a separate threshold and an adjustable

timer to warn of overexcitation. This may be useful for

transformer applications in or near generating stations. A

set of unrestrained differential current elements simply

compares the differential operating current quantity to a

setting value, typically about 10 times the TAP setting.

This pickup setting is only exceeded for internal faults.

The three independent unrestrained differential elements

(87U) provide rapid assertion without delay when

differential operate current levels exceed the 87U pickup

threshold that is set. Typical 87U pickup level settings

are between 8 and 10 per unit of operate current.

Restricted Earth Fault (REF)

Protection

Apply the REF protection feature to provide sensitive

detection of internal ground faults on grounded

wye-connected transformer windings and auto-

transformers. Order the SEL-787-3E with the Slot Ecard

containing the 1 A or 5 A neutral current input for REF

protection. The single-phase 1 A or 5 A CT, provided as

a Slot Eordering option, is used for introduction of neu-

tral operating current. Also, across all available models,

you can program Winding 3 for inclusion in differential

protection or program Phase A and/or Phase B of

Winding 3 for REF protection.

When Winding 3 is set for REF protection, you can

apply the operate quantity (neutral current) to Phase A or

Phase B of Winding 3 for REF protection. Polarizing

current is derived from the residual current calculated for

the protected winding(s). A sensitive directional element

determines whether the fault is internal or external. Zero-

sequence current thresholds supervise tripping.

Overcurrent Protection

The SEL-787 offers instantaneous overcurrent and time-

overcurrent elements. All the elements can be controlled

individually by means of SELOGIC torque control equa-

tions associated with the element.

Instantaneous Overcurrent Elements

The following instantaneous overcurrent elements are

available in the SEL-787.

➤Four instantaneous phase overcurrent (50P) elements

per winding that operate on the maximum of the

phase currents. A peak detection algorithm is used to

enhance element sensitivity during high-fault current

conditions where severe CT saturation may occur.

➤Per-phase instantaneous overcurrent (50P) elements,

one element per phase, that operate on the corre-

sponding phase current of Winding 3 (only available

Operating Region

Restraining Region

IRT

70%

25%

IOP

087P = 0.3

Slope 2

(SLP2)

IRS1 = 6

Slope 1

(SLP1)

SEL-787-3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.

on Winding 3). A peak detection algorithm is used to

enhance element sensitivity during high-fault current

conditions where severe CT saturation may occur.

➤Two instantaneous negative-sequence overcurrent

(50Q) elements per winding that operate on the calcu-

lated negative-sequence current.

➤Two residual instantaneous overcurrent (50G) ele-

ments per winding that operate on the calculated

residual (3I0) current.

➤Two neutral instantaneous overcurrent (50N) ele-

ments that operate on the neutral current associated

with the neutral channel (MOT dependent).

Time-Overcurrent Elements

The time-overcurrent elements support the IEC and U.S.

(IEEE) time-overcurrent characteristics shown in

Table 4. Electromechanical disk reset capabilities are

provided for all time-overcurrent elements. The follow-

ing time-overcurrent elements are available in the

SEL-787.

➤One maximum phase time-overcurrent (51P) element

per winding that operates on the maximum of the cor-

responding winding phase currents.

➤Three per-phase (A-, B-, and C-phase) time-overcur-

rent (51P) elements, one element per phase, that oper-

ate on the corresponding phase current of Winding 3

(only available on Winding 3).

➤One negative-sequence time-overcurrent (51Q) ele-

ment per winding that operates on the calculated neg-

ative-sequence current.

➤One residual time-overcurrent (51G) element per

winding that operates on the calculated residual (3I0)

current.

➤One neutral time-overcurrent (51N) element that

operates on the neutral current associated with the

neutral channel (MOT dependent).

Combined Time-Overcurrent Elements

The combined time-overcurrent elements can be used for

transformers connected to ring-bus or breaker and one-

half systems. The relay only allows you to combine

Winding 1 and Winding 2 and/or Winding 3 and

Winding 4 currents. The combined time-overcurrent ele-

ments support the IEC and U.S. (IEEE) time-overcurrent

characteristics shown in Table 4. Electromechanical disk

reset capabilities are provided for all combined time-

overcurrent elements. The following combined time-

overcurrent elements are available in SEL-787.

➤Two phase time-overcurrent (51P) elements, one each

for combined Windings 1 and 2 and Windings 3

and 4, that operate on the maximum of the corre-

sponding combined phase currents.

➤Two zero-sequence time-overcurrent (51G) elements,

one each for combined Windings 1 and 2 and

Windings 3 and 4, that operate on the calculated zero-

sequence current of the corresponding combined cur-

rents.

Breaker Failure Protection

The SEL-787 offers breaker failure protection for as

many as four three-pole breakers. Use breaker failure

detection to issue re-trip commands to the failed breaker

or to trip adjacent breakers using the relays contact out-

put logic or communications-based tripping schemes.

Breaker failure is initiated by the breaker failure initiate

(BFI) SELOGIC input. The BFI input is typically driven

by local and remote open/trip commands to the breaker.

Once the BFI input is received, the breaker failure

element monitors positive- and negative-sequence

current magnitudes and the breaker auxiliary contacts to

determine when to initiate the breaker failure delay timer.

If current or breaker auxiliary contact status does not

indicate an open breaker condition within the time set by

the breaker failure delay timer, the element issues a

breaker failure trip output.

Figure 5 Breaker Failure Protection

Volts/Hertz Protection

Overexcitation occurs when the magnetic core of a

power apparatus becomes saturated. When saturation

occurs, stray flux is induced in nonlaminated compo-

nents, which can result in overheating. By ordering the

voltage option for the SEL-787, you can add a volts/hertz

element to detect overexcitation. An SEL-787 with

optional voltage inputs provides a sensitive definite-time

delayed element, plus a tripping element with a compos-

ite operating time.

For example, the relay calculates the present transformer

volts/hertz as a percentage of nominal, based on present

measured values and the nominal voltage and frequency

settings. The relay starts a timer when the system voltage

causes an excursion that exceeds the volts/hertz

overexcitation setting. If the condition remains for the set

time delay, the relay asserts and typically provides an

Table 4 Time-Overcurrent Curves

U.S. (IEEE) IEC

Moderately Inverse Standard Inverse

Inverse Very Inverse

Very Inverse Extremely Inverse

Extremely Inverse Long-Time Inverse

Short-Time Inverse Short-Time Inverse

BFD

BFT

BFI

|I1| + |I2|

0.02 • INOM

52A

52ABF

Schweitzer Engineering Laboratories, Inc. SEL-787-3, -4 Data Sheet

alarm function. The element is supervised by the

SELOGIC torque control equation, which enables or

disables the element as required by the application.

Use the SEL-5806 Volts/Hertz User Curve Design

Software to set the user-defined curve (see Figure 6). For

tripping, the relay provides a time-integrating element

with a settable operating characteristic. You can set the

relay element to operate as an inverse-time element; a

user-defined curve element; a composite element with an

inverse-time characteristic and a definite-time

characteristic; or a dual-level, definite-time element.

For any of these operating characteristics, the element

provides a linear reset characteristic with a settable reset

time. The torque control setting also supervises this

element. The tripping element has a percent-travel

operating characteristic similar to that used by an

induction-disk, time-overcurrent element. This

characteristic emulates the heating effect of

overexcitation on transformer components.

Figure 6 SEL-5806 Volts/Hertz User Curve Design

Example

Over- and Undervoltage Protection

The SEL-787 with voltage inputs contains phase over-

and undervoltage, and sequence overvoltage elements

that help create protection and control schemes, such as

undervoltage load shedding or standby generation

start/stop commands. All voltage elements provide two

pickup levels with definite-time delay settings. The fol-

lowing over- and undervoltage elements are available:

➤Phase undervoltage (27P) and overvoltage (59P) ele-

ments that operate on the measured phase-to-neutral

voltages.

➤Phase-to-phase undervoltage (27PP) and overvoltage

(59PP) elements that operate on the measured

phase-to-phase voltages.

➤Negative-sequence overvoltage (59Q) and residual-

ground overvoltage (59G) elements that operate on

the calculated negative-sequence and residual-ground

voltage, respectively.

➤Phase undervoltage (27S) and phase overvoltage

(59S) elements that operate on VS channel voltage.

Loss-of-Potential Detection

The SEL-787 with optional voltage inputs contains loss-

of-potential (LOP) detection logic on the three-phase

voltage input to the relay. The LOP logic detects open

voltage transformer fuses or other conditions that cause a

loss of relay secondary voltage input. The SEL-787 with

optional voltage inputs includes LOP logic that detects

one, two, or three potentially open fuses. This patented

LOP logic is unique, because it does not require settings

and is universally applicable. The LOP feature allows for

the blocking of protection elements to add security

during voltage transformer fuse failure.

Synchronism Check/Station DC

Battery Monitor

The SEL-787 with the voltage option allows you to pro-

gram the VS/Vbat voltage channel for use as either syn-

chronism check or station dc battery monitor. When

programmed as a synchronism-check channel, single-

phase voltage (phase-to-neutral or phase-to-phase) can

be connected to the voltage input for synchronism check

or hot/dead line check across the circuit breaker to which

the three-phase voltages are assigned. When the channel

is programmed for battery monitor, the station dc battery

voltage can be monitored. The relay also allows you to

program over- and undervoltage elements on the voltage

channel.

Over- and Underfrequency Protection

The SEL-787 with optional voltage inputs contains four

frequency elements. Each element operates as either an

over- or underfrequency element with or without time

delay, depending on the element pickup setting.

If the element pickup setting is less than the nominal

system frequency setting, the element operates as an

underfrequency element, picking up if the measured

frequency is less than the set point. If the pickup setting

exceeds the nominal system frequency, the element

operates as an overfrequency element, picking up if the

measured frequency exceeds the set point.

The SEL-787 with optional voltage inputs uses the

positive-sequence voltage to determine system

frequency. All frequency elements are disabled if the

positive-sequence voltage is less than the minimum

voltage threshold.

SEL-787-3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.

Directional Power Element

Protection

The SEL-787 with optional voltage inputs provides two

directional power elements for detecting real (WATTS)

or reactive (VARS) directional power flow levels for the

transformer winding(s) associated with the three-phase

voltage input. Each directional power element has a

definite-time delay setting.

RTD Thermal Protection

When the SEL-787 is equipped with either the optional

10 RTD input expansion card or an external SEL-2600

RTD module with as many as 12 RTD inputs, as many as

12 thermal elements in the relay can be programmed for

two levels of thermal protection per element. Each RTD

input provides an alarm and trip thermal pickup setting in

degrees C, provides open and shorted RTD detection,

and is compatible with the following three-wire RTD

types:

➤PT100 (100 platinum)

➤NI100 (100 nickel)

➤NI120 (120 nickel)

➤CU10 (10 copper)

Operator Controls

Operator controls eliminate traditional panel control

switches. Eight conveniently sized operator controls are

located on the relay front panel (see Figure 7 and

Figure 8). The SER can be set to track operator controls.

Use SELOGIC control equations to change operator

control functions. It is possible to use configurable labels

to change all text in Figure 7 and Figure 8.

Figure 7 Operator Controls (787-4X Model)

Figure 8 Operator Controls (787-3S/3E Models)

The following operator control descriptions are for

factory-set logic.

LOCK: The LOCK operator control blocks selected

functions. Press it for at least three seconds to enable or

disable the lock function. When the LOCK pushbutton is

enabled, the CLOSE operator control is blocked.

BRKRn (n = 1, 2, 3, or 4): Each of these

pushbuttons allows you to select the breaker on which a

CLOSE or TRIP control operation is to be performed.

Only one breaker can be selected at any given time.

Breaker select status for a given breaker is indicated by

the upper pushbutton LED. The lower pushbutton LED

indicates CLOSED/OPEN (RED/GREEN, respectively)

status of the corresponding breaker.

CLOSE and TRIP: Use the CLOSE and TRIP operator

controls to close and open the circuit breaker. You can

program these controls with intentional time delays to

support operational requirements for breaker-mounted

relays. This allows you to press the CLOSE or TRIP

pushbutton, then move to an alternate location before the

breaker command executes.

AUXn (n = 1, 2): The AUXn pushbutton is available

for you to program additional control for your specific

application.

BRKR4

SELECTED

CLOSED/OPEN

BRKR1

BREAKER OPEN

TRIP

AUX1

SELECTED

BRKR2

SELECTED

CLOSED/OPEN

BRKR3

SELECTED

CLOSED/OPEN

ENABLED

LOCK

DISABLED

ENABLED

LOCK

DISABLED

SELECTED

CLOSED/OPEN

BRKR1

BRKR2

SELECTED

CLOSED/OPEN

BRKR3

SELECTED

CLOSED/OPEN

BREAKER OPEN

TRIP

AUX1

AUX2

This manual suits for next models

Other Schweitzer Engineering Laboratories Relay manuals