We will have up to 25 power meter (PM8243) in the same loop communicating by RSTP and IEC 61850 protocol. This is the architecture:
The RSTP root is the Hirschmann switch.
When there is a change in the topology devices have to adjust their settings according to root instructions enabling/disabling their ports. I can see the number of changes in the Hirschmann switch (root) and I can check when the topology is stable (time since topology change) and consulting the MAC addresses connected to each switch port I know where is open the ring.
I observed in PM8243 it takes some minutes for the PM8243 device ring to reach the stable RSTP topology after a change, especially when closing the ring. During the process I have ping with all devices but with delays sometimes around hundreds milliseconds and it seems not to lose communications with 61850 master. The recovery times of ping after topology change seem normal : 1s to 10s
For example I have measured these times with different PM8243 number in the ring:
- 6 PM8243 = about 2 minutes to reach RSTP stable
- 10 PM8243 = about 2 minutes to reach RSTP stable (topology change count=10)
- 15 PM8243 = about 2 minutes to reach RSTP stable (topology change count=12)
- 16 PM8243 = about 4 minutes (topology change count=27)
- 17 PM8243 = about 3 minutes (topology change count=22)
- 23 PM8343= about 46 minutes
I see that from 15 devices it takes longer to reach RSTP stability and it does not always behave the same, even sometimes some PM8243 stays blocked without responding to ping.
If we compare the behavior of P3 against PM8243:
- P3 Relays reach immediately the RSTP stable on the switch, only need 1 count (topology change count=1)
- PM8243 takes many seconds to reach the stable RSTP topology but never stops responding to ping and takes a few seconds to recover ping after a change.
I have some questions:
- Do you know if it is normal for the RSTP ring to take so long to reach stability at startup or after closing the ring?
- Do you know if there is a limit of PM8243 in the same loop to work properly RSTP communication?
This message is posted on the behalf of:
José Miguel Villegas Altea
Customer Project Engineer
Power Systems Iberia Cluster
