Difference between IEC 60870-5-104 and IEC 61850

There seems to be a growing interest to understand what the difference is between IEC 60870-5-104 and IEC 61850. There have been many discussions, complaints, and frustrations ... no wonder.Here is what I have answered to somebody this week:

Dear xxx,

I guess I got it ... you are analyzing the communication inside a station ... to the IEDs (protection, control, ...).

The IEC 60870-5-104 plus a lot of utility or project specific (signal) engineering will do the job – has done it for decades.

The engineering is the key issue when comparing the two standards … if you can compare them at all!!

IEC 61850 offers a lot more than 104 or DNP3 …

From a message overhead point of view, you can say, that both are more or less the same ... because they use both Ethernet and TCP/IP. There is no benefit to use one or the other.

It is likely that IED vendors will mainly focus on IEC 61850 ... and may get rid of 104 in the long run.

I have always said that utilities using 104 in all substations should continue to use it – until they build new substations or do major refurbishments. There is no need to replace a running 104 solution with IEC 61850 ...

Another issue is: To use GOOSE for interlocking … to get rid of copper … or use it for tripping … and use sampled values some time down the road.

Finally there is an issue with manpower: If the utility has senior experts in 104 close to retirement … they should wait until they have retired. Yes! I have seen many old engineers not willing to learn something completely new!!
Click HERE for a detailed comparison written by domain experts.
Hope that helps a bit more.
Best Regards,

Karlheinz