IEC 61850 protocol

Protocol description
Communication line configuration
Communication line protocol parameters
Communication station configuration
Station protocol parameters
I/O tag configuration
I/O tag address
Comments on ABB Substation management unit COM600
Tell commands
Literature
Changes and modifications
Document revisions

Protocol description


The IEC 61850 protocol is an IEC standard designed for communication with Intelligent Electronic Devices (IED) at electrical substations (breakers, protections, transformers, switches, etc).

The IEC 61850 protocol is - like IEC 60870-6 ICCP/TASE.2 - based on the Manufacturing Message Specification (MMS) and therefore the implementation in the D2000 KOM process uses a common MMS framework.

Implementation of the IEC 61850 protocol in the D2000 system supports this functionality:

  1. Periodic reading of values (polling)
  2. Reading of values from predefined Datasets made available in predefined Information Reports - both buffered and unbuffered
  3. Reading of array elements of which are simple values
  4. Writing to simple types of values (writing to structures is not implemented yet)
  5. Writing to array elements of which are simple values
  6. Browsing - when communication is established, the following items can be browsed:

There is no support for the processing of GOOSE and GSSE reports.

The ISO over TCP/IP transmission layer is implemented according to the RFC 1006 specification.

The protocol was tested with software simulators and with ABB Substation management unit COM600.

Communication line configuration


A valid hostname or IP address of the device must be entered according to the rules above.

The port number where the device is listening must also be entered. The ISO over TCP/IP standard uses port 102.

In the case of redundant systems, it is also possible to enter multiple comma-separated names/addresses. When the connection is broken, the communication process will again attempt to establish a connection to the device at the specified address. If the attempt is unsuccessful, then the process tries to establish a connection to the next address. This is repeated cyclically until the connection with one server is established.

Communication line protocol parameters


Communication lines - configuration dialog box - tab Protocol parameters.
These parameters influence some optional parameters of the protocol. You can define the following parameters:

Table 1

ParameterMeaningUnit / TypeDefault value
Address parameters of local side (D2000 KOM process)

Local TSEL (hex)

Octet string that represents the local Transport Selector. It identifies Transport SAP. The maximum size is 32 octets (64 ASCII encoded hexadecimal digits).octet string00 01

Local SSEL (hex)

Octet string that represents the local Session Selector. It identifies Session SAP. The maximum size is 16 octets (32 ASCII encoded hexadecimal digits).octet string00 01

Local PSEL (hex)

Octet string that represents the local Presentation Selector. It identifies Presentation SAP. The maximum size is 16 octets (32 ASCII encoded hexadecimal digits).octet string00 00 00 01

Local AP Title

Local Application Process Title is an identifier that is assigned by an address manager. It represents a specific application process.

string1.3.9999.1

Local AE Qualifier

Integer value used to identify the local Application Entity.string1

Address parameters of remote side (the IED device)

Remote TSEL (hex)

Octet string that represents the remote Transport Selector. It identifies Transport SAP. The maximum size is 32 octets (64 ASCII encoded hexadecimal digits).octet string00 01

Remote SSEL (hex)

Octet string that represents the remote Session Selector. It identifies Session SAP. The maximum size is 16 octets (32 ASCII encoded hexadecimal digits).octet string00 01

Remote PSEL (hex)

Octet string that represents the remote Presentation Selector. It identifies Presentation SAP. The maximum size is 16 octets (32 ASCII encoded hexadecimal digits).octet string00 00 00 01

Remote AP Title

Remote Application Process Title is an identifier that is assigned by an address manager. It represents a specific application process.string1.3.9999.1

Remote AE Qualifier

Integer value used to identify the remote Application Entity.string1
Common address parameters

Bilateral Table ID

Name of the bilateral table. In the case of IEC 61850, this can be an empty string.-
Max MMS Message Size
Maximum size of MMS messages.bytes32000
Max Requests Pending

Maximum proposed transactions that could be sent and unacknowledged. The value can be reduced if the other party suggests a lower value at negotiation.

1 .. 325
Max Indications Pending

Maximum proposed transactions that could be received without sending an acknowledgment. The value is sent to the other party.

1 .. 325
Max Nesting Level
The maximum level of nesting for MMS data structures.1 .. 105

ISO TPDU Size

The maximum packet size for "ISO over TCP" protocol level (according to RFC 1006)8192/4096/2048/1024/512/256/128 bytes1024  bytes
Heartbeat

Timer, which permits the sending ICCP message Identify request to the communicating party to find out the validity of TCP/IP connection. To enable the timer a nonzero value must be specified. If the connection was aborted on the TCP/IP level, fast detection ensures its faster restoring.
This parameter is recommended in situations when transmitting data via large networks or when a small amount of data is transmitted via the active connection. The value 0 (implicit) turns off the HeartBeat timer. A positive value means the seconds to send a Heartbeat message. If any message is sent, the Heartbeat timer is reset and the Heartbeat message is sent only after a timeout elapses without any communication between partners.

sec0
Retry Delay

Delay inserted before repeated attempt to establish the connection after it has been broken. If the connection should be restored as fast as possible, set a small value or 0 seconds.

sec10 sec

Inter Read Timeout

Maximum waiting time to receive TCP data. After this timeout elapses, the possible requirements (data) for sending to a communicating party are checked.
As communication is executed via one thread, the high value can reduce the speed of interaction with the party. The recommended value is 50 to 150 milliseconds.

msec100 msec

Parallel Stations

The parameter activates creating TCP connections for each station. If the device supports multiple clients, communication can be parallelized.
If the parameter is set to NO, a single TCP connection will be created for all communication stations.

YES/NONO

Map IEC 61850 flags

The way IEC 61850 flags are mapped into D2000 flags A .. M.

IEC 61850 protocol has quality flags mapped into 13 bits of the Quality attribute, details are given in the description of the parameter Quality Index:

Mapping can be:

  • None - flags A .. M are not set
  • Simple - Quality attribute directly maps to flags A .. M

Note: after the change of this parameter we recommend a restart of the KOM process or communication partner so that all values come into the system with properly set flags.

None
/
Simple
None

Report Trigger Options

The setting of Trigger parameters used to trigger reports (TrgOps). The following bits are used according to the standard (the numbering is from the highest bit, which is bit 0):

  • bit 0 - reserved
  • bit 1 - data-change
  • bit 2 - quality-change
  • bit 3 - data-update
  • bit 4 - integrity
  • bit 5 - general-interrogation
The default value is 0x74 (all bits are active except integrity - this is activated if the parameter Integrity Period is specified in the report configuration.
Note: ABB Substation Management Unit COM600 required 0x64, it did not support bit 3 - data-update.
1-byte octet string74

Additional Browse Items

The parameter enables specifying additional names of objects to query during browsing for I/O tags. Names must be separated by a space, e.g. "Obj1 Obj2". This makes it possible to handle the situation when IED deliberately does not list some objects in the GetNameList-Response message (response to a requested list of objects within a logical device).
Note: The ABB Substation Management Unit COM600 required parameter setting to LLN0 - this object was not propagated but it was important (it contained e.g. buffered and unbuffered reports).



Authentication Type

Type of authentication. These types of authentication are supported:

  • None - no authentication
  • Password - password-based authentication. The password is transmitted unencrypted within ISO 8650-1 OSI Association Control Service layer.
None
Password
None

Password

Password used if Authentication Type = Password

string
Debug settings

Debug I/O binary packets info

Enables debug information on the level of binary packets. See Note 1.YES/NONO
Debug ISO packet level info
Enables debug information on the ISO OSI layer. See Note 1.YES/NONO
Debug MMS level info
Enables debug information on the MMS data level. See Note 1.YES/NONO

Full IEC61850 level info

Enables debug information on the top level of IEC 61850 data. See Note 1.


YES/NONO
Incoming values info
Enables detailed debug information about incoming values (data values). See Note 1.YES/NONO
Outgoing values info
Enables detailed debug information about outgoing values (data values). See Note 1.YES/NONO

Note 1

If all debug info is enabled, it could cause an overload of communication workstation and decrease of data transfer rate from IED to D2000. After the communication is tuned and debugged, we recommend minimizing the amount of debugging information.

Communication station configuration


Station address

Img. No. 1, Station address

The station corresponds to one logical device. In one physical device, one or more logical devices can be defined. The domain is the name of the logical device values of which we want to read. Multiple stations can be on one line. For each station, a dedicated TCP connection to a defined physical device will be created.

The Browse button enables getting a list of logical devices (if the KOM process is running and communication is established). For Browsing functionality, the device must implement support for getNameList request with parameter ObjectClass = DOMAIN.

Station protocol parameters


Communication station - configuration dialog box - tab Protocol parameters.
These parameters influence some optional parameters of the protocol. You can set the following station parameters:

Table 2

Object groupParameterMeaningUnit / size
Interpretation of quaternary values
QERR Value

Interpretation of Quaternary value Error from the received integer value or from 2-bit State value.

0, 1, 2, 33 (11 binary)
QOFF Value
Interpretation of Quaternary value Off from the received integer value or from 2-bit State value.0, 1, 2, 32 (10 binary)
QON Value
Interpretation of Quaternary value On from the received integer value or from 2-bit State value.0, 1, 2, 31 (01 binary)
QTRANS Value
Interpretation of Quaternary value Transient/Moving from the received integer value or from 2-bit State value. 0, 1, 2, 30 (00 binary)


I/O tag configuration


Permitted I/O tag types: Ai, AoCi, CoDi, Dout, TiA, ToA, TiR, ToR, Qi, TxtI, TxtO

I/O tag address


Img. No. 2, I/O tag address (Data Value)

The configuration of the I/O tag address requires the following data:

I/O Tag Type 

Type of I/O tag:

If the I/O tag representing the report has a text value, the value will be set to the name of the Dataset (the $DatSet attribute) that the report publishes.
If the I/O tag representing the report has an integer or a real value, the value will be

This mechanism can be used to define "watchdogs" guarding, for example, a communication failure, connection failure, or non-working sending of Information Reports.


Name

A unique text string that identifies the IEC 61850 object or its attribute (a reference). The maximum size is 64 characters.
Note: if the I/O tag's address is specified as %IGNORE, such an I/O tag will be ignored.

According to the standard ISO/IEC IEC 61850-8-1 the reference is in form
<LNVariableName>$<FC>$<LNDataName>$<AttributeName> (napr. XCBR1$ST$Pos$stVal)
respectively - if subattributes are used - in form
<LNVariableName>$<FC>$<LNDataName>$<AttributeName>$<subDataAttributeName> (napr. XBCR1$ST$Pos$origin$orCat)
where:

The standard defines the following naming conventions for individual components of a reference:

Defined Functional Constraints according to ISO/IEC IEC 61850-8-1:


FC Name

Description

MX

Measurands (analog values)

STStatus information
COControl service parameters
CFConfiguration
DCDescription
SP

Setting (outside setting group)

SGSetting group
RPUnbuffered report control blocks
LGLog control blocks
BRBuffered report control blocks
GOGOOSE control blocks
GSGSSE control blocks
SVSubstituted values
SE

Setting group editing

MSMulticast Sampled Values control block
USUnicast Sampled Values control block
EX

Name space for model extension

SRService tracking
OROperate received
BLBlocking


Names of DataObject Attributes and SubDataObject Attributes are defined in ISO/IEC IEC 61850-7-3 and the following table contains only the most common ones:

Attribute Name

Description

ctlModelSpecifies the control model of IEC 61850-7-2 that corresponds to the behavior of the data.
dTextual description of the data.
evalTmTime window applied to interharmonic calculations. The value shall be represented in ms.
frequencyNominal frequency of the power system or some other fundamental frequency in Hz.
instMagMagnitude of the instantaneous value of a measured value.
magDeadbanded value. Shall be based on a dead band calculation from instMag.
numCyc

The number of cycles of power frequency, which are used for harmonic, subharmonic and interharmonic calculations.

numHar

The number of harmonic and subharmonics or interharmonic values that are to be returned as the value attribute.

phsAHar, phsBHar, phsCHarThis array shall contain the harmonic and subharmonics or interharmonic values related to phase A (resp. B, C).
phsABHar, phsBCHar, phsCAHar

This array shall contain the harmonic and subharmonics or interharmonic values related to phase A to phase B (resp. B to C, resp. C to A).

qQuality of the attribute(s) representing the value of the data
setCharactThis attribute shall describe the curve characteristic.
setMagThe value of an analog setting or set point.
stValThe status value of the data
swRevSW-revision
t

The timestamp of the last change in one of the attribute(s) representing the value of the data or in the q attribute.

unitsUnits of the attribute(s) representing the value of the data (ISO/IEC IEC 61850-7-3  Annex A)
vendorName of the vendor.


Data Type

The list of permitted data types:

Data TypePopis

--- Autodetect ---

The Data Type will be queried by a GetVariableAccessAttributes-Request message after the connection establishment.

Note 1: information is currently stored only in KOM process memory, therefore after its restart and the first connection establishment the data type detection is performed for all Autodetect I/O tags.
Note 2: data types State and StateQ are undistinguishable by this mechanism, therefore objects of these types are detected as StateQ.
Note 3: the same mechanism for data type detection is used in browsing.

Discrete *ICCP: Integer 32-bit value signed
DiscreteQ *
ICCP: Integer 32-bit signed value + ICCP Validity
DiscreteQTimeTag *
ICCP: Integer 32-bit signed value + ICCP Validity + Time stamp
DiscreteExtended *
ICCP: Integer 32-bit signed value + ICCP Validity + Current Source + Extended time stamp
Real *
ICCP: Float 32
RealQ *
ICCP: Float 32 + ICCP Validity
RealQTimeTag *
ICCP: Float 32 + ICCP Validity + Time stamp
RealExtended *
ICCP: Float 32 + ICCP Validity + Current Source + Extended time stamp
State *ICCP: Discrete 2-bit value
StateQ *ICCP: Discrete 2-bit value + ICCP Validity
StateQTimeTag *
ICCP: Discrete 2-bit value + ICCP Validity + Time stamp
StateExtended *
ICCP: Discrete 2-bit value + ICCP Validity + Current Source + Extended time stamp
BooleanBoolean value
Float3232-bit real value
Float6464-bit real value
Integer88-bit signed integer value
Integer1616-bit signed integer value
Integer3232-bit signed integer value
Integer6464-bit signed integer value
Unsigned88-bit unsigned integer value
Unsigned1616-bit unsigned integer value
Unsigned2424-bit unsigned integer value
Unsigned3232-bit unsigned integer value
OctetStringVariable-length binarny string
VisibleStringVariable-length text string
UnicodeStringVariable-length text string in UTF8 encoding
BitStringVariable-length bit string
UtcTimeAbsolute time (format seconds since 1.1.1970 + milliseconds)
TimeOfDayAbsolute/relative time (format seconds and milliseconds of a day + optionally number of days since 1.1.1984)
Array of BooleanAn array of Boolean values
Array of Float32An array of 32-bit real values
Array of Float64An array of 64-bit real values
Array of Integer8An array of 8-bit signed integer values
Array of Integer16An array of 16-bit signed integer values
Array of Integer32An array of 32-bit signed integer values
Array of Integer64An array of 64-bit signed integer values
Array of Unsigned8An array of 8-bit unsigned integer values
Array of Unsigned16An array of 16-bit unsigned integer values
Array of Unsigned24An array of 24-bit unsigned integer values
Array of Unsigned32An array of 32-bit unsigned integer values
Array of OctetStringAn array of variable-length binary strings
Array of VisibleStringAn array of variable-length text strings
Array of UnicodeStringAn array of a variable-length text string in UTF8 encoding
Array of BitStringAn array of variable-length bit strings
Array of UtcTimeAn array of absolute times (format seconds since 1.1.1970 + milliseconds)
Array of TimeOfDayAn array of absolute/relative times (format seconds and milliseconds of a day + optionally number of days since 1.1.1984)

Structure

Structure or Array. The structure can contain simple types, arrays, and nested structures. Arrays consist of elements that can be simple types (here, however, it is more efficient to use some of the Array of types), structures, and arrays. If a data type of an I/O tag is configured as a Structure, the Array Index parameter specifies the complex address of the structure element to be read in the I/O tag.
Note: multiple I/O tags can have the same Name parameter, the Structure data type, and differ only by the Array Index parameter to access the various elements of the structure. If these I/O tags are configured with the I / O Tag Type = Periodically polled value, a single reading request will be sent for all such points.

Note * - types marked with asterisk (*) are used in IEC 60870-6 ICCP/TASE.2 protocol (which uses a common MMS framework). For IEC 61850, we recommend not using these types.



Array Index

Note:  For arrays of elementary types (Array of), the IEC61850 supports writing the received values to a target column of a structured variable. 
If the Destination tab in the configuration of the I/O tag has a Destination column set to a column of a structured variable, the corresponding array items will be written into it. This only works if the Array Index is not entered or is equal to 0.


Quality Index

For the Structure object type: it is possible to specify the index where IEC 61850 Quality is located. The format of the Quality Index is the same as a complex address.
IEC 61850 Quality is of Bitstring type with a length of 2 bytes. 13 quality bits are defined as follows (the standard numbers the bits so that the highest bit is 0 and the lowest is 15):

Bit(s)Note

0-1

Validity:

ValueDescriptionD2000 attribute
0 0GoodValid
0 1InvalidInvalid
1 0Reserved-
1 1QuestionableWeak


2

Overflow

3

OutofRange

4

BadReference
5Oscillatory
6Failure
7OldData
8Inconsistent
9Inaccurate
10Source ( 0-Process, 1-Substituted)
11Test
12OperatorBlocked
13-15unused bits

If at least one of bits number 2-12 is set, the value in D2000 has a Weak attribute.
See the example in Time Index



Time Index

For the Structure object type: it is possible to specify the index where the timestamp is located. The format of the Time Index is the same as a complex address.

If the Time Index is not specified, the timestamp of the information report (for I/O Tag Type=Buffered/unbuffered report value) or the current time (for  I/O Tag Type=Periodically polled value) will be used.

Example: information report contains a structure that contains a Bitstring value followed by quality and timestamp. Therefore the object's address has Array Index = 0, Quality Index = 1 and Time Index = 2.

Log lineNote

14:35:36.198 09-07-2018|D|MMS>  [1]     STRUCTURE{

Object of Structure type

14:35:36.200 09-07-2018|D|MMS>  [1]       Bitstring=<80>

Value (Array Index = 0)

14:35:36.202 09-07-2018|D|MMS>  [1]       Bitstring=<00><00>

Quality (Quality Index = 1)

14:35:36.204 09-07-2018|D|MMS>  [1]       seconds= 1531115260 fraction= 3223372800 (09-07-2018 07:47:40.751)

Timestamp (Time Index = 2)
14:35:36.206 09-07-2018|D|MMS>  [1]     }End of Structure object



Integrity Period

This parameter is enabled for the I/O tags of the "Buffered/unbuffered Report" type and it specifies a period (in ms) after which a report containing the values of all objects in the given datasheet is generated. Therefore, if a loss of value has occurred in some way, this Integrity Report will periodically restore the integrity of the data. Value 0 turns off the generation of the Integrity Report. The non-zero value causes a write to the $IntgPd report attribute during the report activation. 
Note: Not all IEC 61850 servers support this parameter.


Browse

For the I/O tags, it is possible to find a list of objects and their data types, as long as the KOM process is running and communication is established. 
When a Browse button is clicked, the IEC61850 Browser window opens, and the KOM process begins to query the list of objects with the GetNameList-Request message and then their data types with the GetVariableAccessAttributes-Request message.

Img. no. 3, the IEC 61850 Item Browser window

Meaning of individual choices and buttons:

Auto

If this choice is active, the Data Type will be set to Autodetect, otherwise to value discovered during browsing, e.g. Boolean or Integer32.

Copy all to clipboard

Copies the displayed objects and their respective data types into the Windows Clipboard.

Refresh

By pressing the Refresh button it is possible to enforce re-querying of the list of objects from the device. By default, the KOM process reads the list of objects and their respective data types only during the first browse request and stores them in memory. This reading can take a longer time, depending on the number of objects and speed of the device. These cached lists are sent to the CNF process(es), so that consecutive filling of the Browse window is fast.

Filtering in the list of objects

The browse window enables filtering by the object name and data type. It is not necessary to enter the full text in the filter field. The notation "*FILTERED EXPRESSION*" is supported. The symbol * represents any text before and after the expression (e.g. *momen*).

Note 1

In addition to objects with supported data types (Boolean, Integer32 ...), the object list can contain objects with Structure type. These are structured objects that can not be directly read. The implementation only supports work with simple types and fields whose elements are simple types, therefore individual items of structured objects need to be communicated.

Note 2

In D2000 versions from 20th December 2018 and newer, the recycling of browser dialog has been implemented. If the dialog is closed by the Cancel button or after selecting an object, it is actually only hidden and it is available for browsing by another I/O tag within the same station so that the tree structure of the browsed objects is preserved. Clicking on the close icon at the top right corner will cause the dialog to be really closed.

Note 3

Writing to I/O tag with the Array data type (Array of *) is supported for text I/O tags (TxtO).  When writing, individual values must be separated by commas, e.g. "1, 2, 3, 7".

Comments on ABB Substation management unit COM600


During the testing of the ABB Substation Management Unit COM600 the following facts were found:

Tell commands


CommandSyntaxDescription
STWATCHSTWATCH StationNameTell command sends requests for reading values of all I/O tags.

Literature


Changes and modifications


-

Document revisions



Communication protocols