Feeder_2 logic scheme, Normal operation - control, Normal operation - protection – Basler Electric BE1-851 User Manual

Page 173: Normal operation - reclosing, Feeder_2 logic scheme -17, Normal operation - control -17, Normal operation - protection -17, Normal operation - reclosing -17

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SL-143 = 0

SL-243 = 0

SL-343 = 0

SL-101 = 0

SL-VOA = ALMMAJ

SL-VO1 = VO8*IN4+BFPU+VO11*/IN4

SL-VO2 = VO9*IN4

SL-VO3 = IN4

SL-VO4 = VO12*/IN5*IN4

SL-VO5 = BFT

SL-VO6 = 0

SL-VO7 = 0

SL-VO8 = 51PT+51NT

SL-VO9 = 50TPT+50TNT

SL-VO10 = VO11

SL-VO11 = 50TPT+50TNT+51PT+51NT

SL-VO12 = 50TPPU+50TNPU+51PPU+51NPU

SL-VO13 = 0

SL-VO14 = 0

SL-VO15 = /IN4

Feeder_2 Logic Scheme

Logic scheme Feeder_2 is meant for use on a feeder breaker and provides overcurrent, breaker failure

protection, reclosing, and the control functions required for a typical feeder in a non-directional

overcurrent protection application. This logic scheme is intended for use in conjunction with other

programmable relays using the BUS and BACKUP logic schemes to provide protection when the relay is

out of service.
Automatic reclosing uses a reclose initiate scheme and is initiated by protective trip.
When used with other programmable relays using logic scheme BUS and BACKUP, this scheme can

provide complete high-speed overcurrent protection for the transformers, bus, and feeders in a radial

system substations. The components of Feeder_2 logic are summarized in Tables 8-9 through 8-12.

Figure 8-5 is a one-line diagram of Feeder_2 logic and Figure 8-6 represents the logic settings and

equations of Feeder_2.

Normal Operation - Control

The virtual breaker control switch is programmed to provide manual trip and close control of the breaker.

The control functions of this logic scheme use both traditional contact sensing inputs and virtual switches.

Virtual switches that are not needed may simply go unused. The protection engineer may choose to free

up contact sensing inputs for other uses by using the virtual switches exclusively for the various control

functions.

Normal Operation - Protection

All overcurrent function blocks and the breaker failure function block re-trip output are enabled in

Feeder_2 logic for tripping via OUT1. The 150T function blocks are set up as high set instantaneous

functions which drive the recloser to lockout when they trip. Setting the pickup at 0 in the four setting

groups can individually disable each overcurrent function block. The 50TN, 50TQ, 51N, and 51Q function

blocks are torque controlled by either IN3 or virtual switch 243. All N and Q function blocks or only the

51N and 51Q function blocks may be inhibited. This is done in BESTlogic by modifying the inputs to the

function blocks.

Normal Operation - Reclosing

The reclosing logic in Feeder_2 uses a reclose initiate (RI) scheme where each step in the reclosing

sequence is initiated by a protective trip. Setting the first reclose time at zero in the four setting groups

can disable the recloser function block.
Reclosing can be disabled by either IN2 or Virtual Switch 143 that is connected to the drive to lockout

(DTL) input of the recloser function block. In this scheme, enabling the recloser after a “one shot” trip will
9289900990 Rev R

BE1-851 Application

8-17

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