MiCOM P740 - PU and CU communication Capability

[Sabhanayagan_Matheswaran]

Hi Team,

We are working in a tendering opportunity, were the client requirement is to have redundant Central Unit system for Busbar protection. As a standard practice, will use PU - CU communication via single fiber optic cable from Channel-1 of P742/P743 to P741 communication slot. If I follow the standard procedure, to achieve the redundancy I need to duplicate the system, which add more cost to project and there is spare constraint as well to mount the 2 x Peripheral units in switchgears.

Instead of proposing the duplicated system, each P742 / P743 has 2 communication channels at the relay slots, can we use 1 channel for 1 CU (Main-1) and 2nd Channel for 2 CU (Main-2). Theoretically since the PU address is same both the CU can able to read the same data and work as a Main-1 & Main-2. Is this functionally correct, does P742 / P743 is functionally can communicate to 2 CUs simultaneously both Read & Write.

Thanks,
Sabhanayagan

[Araceli_Monje]

@HenriGRASSET , hi, could you please support with this question about P740?, thx.

[HenriGRASSET · Accepted solution]

Hello,

Even if on the communication boards there are two communication channels, it is not possible to use both at the same time and thus not possible to have redundancy.

“N-1” redundancy is to be immune to one component being faulty. Having only one Central Unit to redundant Peripheral units or Peripheral units connected to redundant Central units does not provide it.

This redundancy is often done using a P740 and a P746 (one box or three box mode) that requires much less IEDs and space and provides different types of algorithms.

Regards