Friends,

Here i am posting a question regarding Micro processor based relay in MV Switch gear which is Provided for measurement/Monitoring parameters of HT motors.

One of our specifications say that, "For interfacing 33 KV PANEL, 6.6KV SWITCHBOARD, PMCC and DG BREAKER PANEL to control room regarding microprocessor relays, monitoring/measuring parameters (or from load manager) for each feeder with MODBUS PROTOCOL only one DATA CONCENTRETOR shall be provided by LSTK bidder to receive inputs from above panels and output shall be connected to control room PLC "

However, i am not much clear about the functionality of micro processor based relay. As per my understanding micro processor based relay shall control, monitor and provide the protection for motor through the communication link provided for the relay with the DCS.

So i understand that no separate IRP or I/O Count or any Hard wired signals need not be considered for the following control and status indications for a typical HT motor as everything can be controlled and monitored through communication port.

i) Pump Start command-DO.
ii) Stop command-DO
iii) ESD Trip Command-DO
iv) Permissive Start Command-DO
v) Run Indication-DI
vi) Stop Indication-DI
vii) Fault Indication-DI
viii) Ready to start-DI

To add, my specification clearly clarified that for LT motors there is Smart MCC and for HT motors there is conventional MCC with microprocessor based relay for motor control

So i am clear about LT motors as it says Smart MCC so i am not considering anything( IRP or I/O Count or any hard wire signals)

But for HT motor as it says conventional MCC with microprocessor relay really confuses me whether to consider IRP or I/O Count or Hard wired signals! To add more to my confusion the document says about "data concentrator" which i really don't know.

The I/O Schedule provided by client takes control signals to PLC and status signal to MCC which are not serial linked.

Please clarify me regarding Microprocessor based relay, data concentrator and I/O Count or hard wire signals that need to be considered.

Please clarify me as soon as possible.

Thanks in advance.

With Regards,
Gopi

 

Typically a "data concentrator" is utilized to reduce communication load on the DCS and to consolidate all all of the data from the various field devices into a single communication table, that can easily be read by the DCS. In order to answer your questions you will need to know exactly which devices the data concentrator is communicating to and the specific data is being retrieved. For the standard MCC that does not utilize any "smart devices" you will need to determine exactly which signals are required for your control strategy.