Monday, December 17, 2012

IEC 61850 Edition 2 Eases the use of the Standard

Is that really true? Sure it is.

First of all, when I talk about “IEC 61850 Edition 2” in this post I mean the Edition 2 of the core parts like IEC 61850-6, –7-x, and -8-1.

Most of the definitions of these Edition 2 core parts have not been touched! Several “overheads” in the former edition have been removed! There are a few cleaned-up definitions (that had already been solved during the tissue process), and there are several new definitions (mainly in the model documents 7-3 and 7-4). New logical nodes like STMP (Supervision Temperature) have no impact on the other definitions – they are independent new definitions for NEW applications.

Let’s look at examples of the “overhead” of mandatory data objects in each and every logical node in edition 1 of part 7-4:

The common data objects in ALL logical nodes in IEC 61850-7-4 Edition 1 required the following four (4) mandatory objects:

NamPlt   LPL
Mod      ENC
Beh      ENS
Health   ENS

According to IEC 61850-7-4 Edition 2 this has been reduced to one single mandatory (1) data object for all but one LN - LLN0:

Beh      ENS

This could save a lot of memory and processing … we have learned to improve the standard – that is what most people expected! Or?

Most basic definitions in common data classes are still the SAME; a lot of devices (edition 1 or edition 2 based) work smoothly together when we look of basic use cases:

SPS (single point status):
stVal   BOOLEAN
q       Quality
t       TimeStamp

DPS (double point status):
stVal   CODED ENUM
q       Quality
t       TimeStamp

MV (measured values):
mag     AnalogueValue
q       Quality
t       TimeStamp

Now when we compare these basic “signal” types with … we will figure out that there is almost NO real difference! Please check the following mapping from IEC 61850 to DNP3 (according to IEEE P1815.1 Draft Standard for Exchanging Information between networks Implementing IEC 61850 and IEEE Std 1815 (Distributed Network Protocol - DNP3):

Mapping for DPS (double point status):

image 

DBBI = Double-Bit Binary Input
BI    =  Binary Input

Do you think this is a crucial difference?

Some people want to make us belief that IEC 61850 is complex. Check on your own, please. If you need help, let me know.

1 comment:

Rodney Hughes said...

Just a clarification on the first point.
Whilst the Mandatory common parts for all LN have been reduced from “Mod”, “Beh” and “Health” to just ‘Beh”, the Mandatory requirement for the other two has not been discarded but have now been transferred to the Logical Device level