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Implementation Trip Circuit Supervision /

Trip Coil Supervision in SEL Relays

Using SELogic Equations

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ANSI ( 74 :Trip Circuit Supervision/Trip Coil Supervision) :

Scheme description :

TCS Scheme is designed to provide supervision of the trip coil with the breaker open or closed. Since

two opto inputs are used, this scheme is compatible with latched trip contacts. When the breaker is closed and there is no

trip signal, supervision current passes through the opto input no.1 and the trip coil. When breaker is open the current flows

through opto no.2 and trip coil .So, the supervision current is maintained through the trip path with the breaker in either

state, thus giving full supervision.

Power Supply

+

-

IN101

IN102

A10

A11

A12

A01

A02

Trip Circuit Supervision / Trip Coil Supervision

SEL-710LI+

LI-

DC Elementary

Supply.

O C

BUS SIDE

Motor

P1

P2

R

Y

B

N

Test Block

IR

IY

IB

CT

Inputs

Z01

Z02

Z03

Z04

Z05

Z06

LI+

LI-

OUT103

A05

A06

OUT104

A07

A08

OUT 302

C03

C04

52a

52b

Circuit Breaker

DC Supply.

Binary Inputs & Outputs

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Trip Circuit Supervision/Trip Coil Supervision configuration logic using SELogic equations and Graphical logic:

Using SELogic equations, The Trip circuit supervision/Trip Coil Supervision configuration will be as the following:

SV01 := NOT (IN101 OR IN102 )……SELogic variable number 01 will assert if both IN101 and IN102 not available .

SV01PU:=0.5 ( Seconds) … The SELogic variable number 01 timer ( SV01 will pick up after 500ms ).

SV01DO:= 0.5 (Seconds )…. The SELogic variable number 01 timer ( SV01 will Drop off after 500ms ).

T06_LED := SV01T … LED number 6 assigned to the output of the SELogic variable 01 .

Using SEL Graphical logic , We can represent the above SELogic equations which representing the TCS as the following :