How to control MV motor starter by DCS PLC

[Parkpower]

Hi everyone,

We use motor starter c/w fused contactor to control 6kV motors. The 6kV motors and low voltageg 380V motors are all controlled by DCS system.

For the LV motors, smart or intelligent MCC are used,such as Siemens Smart Tiastar MCC.Each MCC cubicles are serial linked to an interface master which is linked to DCS PLC by one serial data cable.

As for MV motors controllers, MV motor relaying like GE 469 or Schneider Sepam relaying are installed. Each relaying has communication port like RS485 or IEC 61850. Can we use the same method as LV MCC to connect these relayings to one interface master then link the master to DCS PLC or shall we hardwire each relaying to DCS PLC?

Thanks,

Parkpower

 

[dpc]

You can do it either way. If you want to go through the protective relay, you'll have to sort out the necessary communications interfaces, protocols, addressing, etc.

I think your operators might be more comfortable with hard-wired I/O from the PLC when it comes to stopping the motors, rather than relying on a serial interface.




"An 'expert' is someone who has made every possible mistake in a very narrow field of study." -- Edward Teller

 

[jraef]

If you go with the hard wire route, you will not have the serial communications with your DCS, for instance the fault cause, running data, statistics etc. If you have a sophisticated protection relay, I would opt to use as much of its capability as possible. There are many gateway products that can convert the RS485 Modbus RTU protocol of the relays into something that your DCS can work with. What DCS do you have?


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[dpc]

Well, you can still use the serial port for other functions and monitoring even if you elect to hardwire the start/stop function. That is quite common.

"An 'expert' is someone who has made every possible mistake in a very narrow field of study." -- Edward Teller

 

[ScottyUK]

Agree with DPC - hardwire the breaker command functions and the breaker status signals, then suck the rest of the data out over a link. For a specific comms technology I'd opt for fibre ethernet for speed, reliability and ease of obtaining parts if that were an available choice. Fibre is a great choice in a switchroom environment because it is immune to the electrical interference.


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If we learn from our mistakes I'm getting a great education!

 

[oldfieldguy]

And install an "emergency stop" button on the door of the starter that will over-ride all the other controls, just in case.



old field guy