Relay and Breaker Control

[SAM800]

Hi,

I have been reading posts here for a while and found it useful. I am a recent graduate and working as an EIT for the few months. I have been asked to read an old 4.16 kV switchgear specs and create a new specs for 13.8 kV switchgear with an F35 relay. Only one feeder breaker on the secondary of a 15 MVA transformer.

Question: Medium voltage circuit breaker can be opened and closed by both from the circuit Breaker ?

Is it possible to close the breaker frome the F35 relay face plate as well.

I came across some shop drawings from ABB and it has on Trip contatcs 52CS and Close COntacts 52 CS.
What does this mean.
Thanks

 

[dpc]

CS = control switch

The breaker is closed by energizing the closing coil and tripped by energizing the trip coil (some new breakers with magnetic actuators are a little more complicated).

So contacts that are to trip the breaker are placed in parallel, such that closing any one contact will energize the trip coil which causes the breaker to trip. You can have as many devices as you want that can trip the breaker. And there can be a lot of them in some cases.

 

[SAM800]

Thanks dpc

So I assume CS is a control switch: It is a manual switch located either on the protection control panel or circuit breaker.

I noticed on one of the shop drawings for F35 relay.Please see attachment. in file 52CS.jpeg,

http://files.engineering.com/getfile.aspx?folder=4845c683-c725-4e3c-85d6-b82d1ee9db38&file=52CS.JPG

In the second file:

http://files.engineering.com/getfil...3-4290-90a1-c2018b0f6c38&file=CBSchematic.JPG

These two contacts are shown wired to the circuit breaker closing and trip circuit.
Does that mean, Contacts H2 and H3 have to be programmed to have logic 1 to close and trip the breaker.

If I want a remote operation of the breaker with a switch, how can I do that.
I know it is to much information to ask. Any comment would help.

Thanks

 

[dpc]

For remote operation, you just run wiring from the switch contact to the breaker.

You need to download the instruction manual for the F35 and take a look at it. I assume you will need to configure the output contacts for the desired functions, if that is your responsibility.

 

[NCTHAI]

Tripping from protection relay is fine. However, closing from protection relay (even from modern feeder management numerical relay) needs considerable logics in place.

I would not recommend auto closure unless CB is used in some sort of power supply change over schemes.

Feeder management relays also needs good engineering and logic building to close the feeders on auto.

It is well understood that feeder management relays just replace hard wire schemes but anything new or change to be implemented cautiosly.

NC

 

[rbulsara]

sam800:

I am not reviewing your drawings or particular F35 relay, but to answer your question, yes the modern multifuntion relays do have the ability and provisions to close and open the breakers. It needs to be programmaed and wired accordingly. However as NCTHAI indicated it is not advisable.

In fact if it is a utility main breaker, most utiltiy company will require the closing ability to be disabled or not wired.

In my opinion the protective relay application should be limited to its tripping functions in case of a fault or abnormal conditions.

 

[oldfieldguy]

Sam800:

What you're talking about doing is well within the capabilities of the F35 if you have the correct I/O modules installed AND you write the correct logic into the setpoint file.

Properly set up, the F-35 will allow you to control your breaker from the front panel or via remote terminal, but the end user has to program these functions.

We are presently using remote open and close control via F35, F60, T60 and G60 relays from GE. It is working well for us, but there was considerable effort going into upgrading our system protection from 1970's discrete electromechanical protection to the GE UR platforms. It is well to sit down and decide how you want all this to work.

Yes, some people do simply change out the old electromechanicals to new multifunction relays without using some of the features available. They're missing opportunities to make a more safe and convenient power system, in my opinion.

old field guy

 

[sobeys81]

Oldfieldguy,

A quick question here and sorry for meddling in to SAM800's post.

Operating a F35 and T60 remotely for closing or opening a breaker is normally done through PLC?

 

[oldfieldguy]

sobeys81-

It can be done through the PLC. The relay is given a ModBus slave address and can be commanded through it.

We chose to have a separate HMI as a control station. It gives us a graphic representation of breaker status and loads and allows us to open and close breakers.

We chose the separate HMI because we do not want our operators to have switching capability. That is a province of our maintenance department. Our electricians do not touch the operator's consoles, and the operators don't operate our power system equipment.

old field guy