Breaker Trip Circuit Supersvision

[WiringBoy]

HI,
I AM ASKING THIS QUESTIONS, WHEN I HAVE EXHUASTED ALL AVENUES FOR AN EXPERT AND SATISFACTORY OPINION IN MY NEIGHBOURHOOD.
I WOULD SINCERELY APPRECIATE YOUR OPINION.

Background:
Project involves replacing an old outdoor GE Oil type 13.8 kV breaker. Field wiring would remain intact and breaker will be removed. There is an attachment with this question which has two Parts 1 and II. My question is regarding a trip supervision circuit which used to be a trend of the past and I have to implement same functionality in new design.

PART 1(AS SHOWN IN ATTACHMENT):
PART 1 IS DIVIDED IN TWO SECTIONS:

RIGHT HAND OF THE DIAGRAM:

SHOWS A 125 V DC TRIP CIRCUIT OF THE EXISTING CIRCUIT BREAKER. IT USES A 52-SUP RELAY WITH A 2000 OHM RESISTOR IN SERIES WITH CIRCUIT BREAKER TRIP COIL TO KEEP THE RELAY 52-sup ENERGIZED TO MONITOR THE TRIP COIL CONTINUITY. 43/R IS THE REMOTE POSITION OF SELECTOR SWITCH WHICH IS ALWAYS CLOSED. THERE IS A SMALL TRICKLE CURRENT FLOWING THROUGH THE TRIP COIL NOT ENOUGH TO TRIP IT BUT enough to PICK THE RELAY COIL TO CLOSE A CONTACT (1-2).
52 SUP REALY IS ABB ASEA RXMA1 RK211 073 AN. I HAVE ALSO ATTACHED THE RELAY CATALOUGE.

LEFT HAND OF THE DIAGRAM

SHOWS A 48 V DC PANEL TURNING A GREEN LIGHT ON TILL RELAY 52-sup IS ENERGIZED BY CLOSING CONTACT 1-2.

PART 2 OF THE ATTACHMENT:

MY NEW BREAKER HAS IS ABB R-MAG BREAKER. IF I TRY TO INSTALL THE RELAY AT THE SAME LOCATION USING A TRICKLE CURRENT, IT MIGHT TRIP THE BREAKER. SO HERE IS MY PLAN AND I WANT TO HEAR YOUR OPINION ON MY TAKE On THE SITUATION. BREAKER OFFERS A UNIT READY CONTACT THAT OPENS WHEN THERE IS PROBLEM WITH BREAKER TRIP CIRCUIT.

SOLUTION: I AM WIRING THIS RELAY IN PARALLEL WITH TRIP CIRCUIT WITH SAME 52-SUP RELAY IN SERIES WITH ALL THE CONTACTS TO ACHIEVE TRIP CIRCUIT SUPERVISION FUNCTIONALITY. I AM SATISIFIED WITH THE LOGIC BUT NOT HOW IT IS IMPLEMENTED.

QUESTION# 1

IS THERE ANY ISSUE IN THIS CIRCUIT BEING IN PARALLEL WITH THE TRIP CIRCUIT OF THE CIRCUIT BREAKER(SEE PART/SECTION 2 OF THE ATTACHMENT)

QUESTION# 2

RELAY MANUAL OF BREAKER ATTACHED ON PAGE 4/20, TABLE 1 ROW 5, SHOWS THE BREAKER COIL RATED AT 12 V AND TABLE 2, ROW 4 SHOWS FOR MODEL RXMA1 COIL RESISTANCE 9680 OHMS.

IN THE PART 1 DESIGN, THERE WAS A TRIP COIL RESISTANCE IN SERIES WITH THE SUPERVISION CIRCUIT AND VOLTAGE DROP ACROSS RELAY COULD BE LESS THAN 12 V. BUT IN NEW DESIGN, THERE IS NO TRIP COIL, THE VOLTAGES RELAY COIL WILL BE DIVIDED BETWEEN 125 V DC BASED ON SERIES RESISTANCE 2000 OHM AND COIL RESISTANCE 9680 OHMS, WHICH IS MORE THAN 12 V.

IN QUESTION#2 , AM I GETTING ANY HERE WITH THIS VOLTAGE DROP LINE OF THOUGHT?

WHAT IS YOUR SUGGESTION GUYS. TRUST ME... I KNOW I AM MISSING SOMETHING HERE BIG TIME.

 

[WiringBoy]

Please see the relay catalouge

 

[jghrist]

Part I monitors the condition of the trip coil. If the trip coil fails open, then there will be no voltage across 52SUP and the contacts will open.

Part II does not monitor the trip coil, it only monitors the position of the breaker auxiliary switch. Unless the "BRK UNIT RDY CONTACT" monitors the trip coil. I'm not familiar with this term.

Does the 52SUP do anything other than turn on the green light when the breaker is closed and the trip coil is healthy?

 

[rasevskii]

Wiringboy:

Where do you get the 12V (Twelve volt)from? You are using a 125V Dc system. If the trip supervision is connected the same way as it was on the old breaker, it should work, providing that the trip coil resistance of the new breaker is around the same ohms as the old.
If the new trip coil is high resistance or some electronic type of circuit, then it may not work, you may get a standing trip due the supervision current. In this case you should contact ABB for a recommended supervision method for the new. I am assuming here that the new breaker has a 125V trip circuit and not some other voltage.

A disadvantage of this system of supervision always was that a shorted or earth faulted trip coil would not be necessarily detected and that the alarm will always momentarily operate when a trip actually occurs.

rasevskii

 

[switchgearman]

Look at the diagram in the ABB R-Mag Instruction Book. You can't use a trip coil monitor on this breaker, it's enough to trip the breaker. Use the "Not Ready" contact, this monitors the control board microprocessor, trip and close functions. Some customers use the "Ready" contact as a similar function.
A 50 ohm/100 watt resistor is used in parallel with the virtual trip coil to draw enough current for e/m relay targets.

 

[WiringBoy]

Thanks a lot Gentleman for your comments.

Switchgearman,

Yes, I am using Unit Ready contact to acheive the similar functionality and the breaker manual also considers this a trip coil continuity contact. For now, my problem is solved.

Thankyou all.....