EN IEC 61869-9:2019/prA1:2026

SLOVENSKI STANDARD
01-maj-2026
Instrumentni transformatorji - 9. del: Digitalni vmesnik za instrumentne
transformatorje - Dopolnilo A1
Amendment 1 - Instrument transformers - Part 9: Digital interface for instrument
transformers
Messwandler - Teil 9: Digitale Schnittstelle für Messwandler
Amendement 1 - Transformateurs de mesure - Partie 9: Interface numérique des
transformateurs de mesure
Ta slovenski standard je istoveten z: EN IEC 61869-9:2019/prA1:2026
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

38/847/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 61869-9/AMD1 ED1
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2026-03-13 2026-06-05
SUPERSEDES DOCUMENTS:
38/715/CD, 38/720A/CC
IEC TC 38 : INSTRUMENT TRANSFORMERS
SECRETARIAT: SECRETARY:
Italy Mr Filippo Frugoni
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
TC 13,SC 17C,TC 57,TC 85,TC 95,TC 115
ASPECTS CONCERNED:
Digital content,Electricity transmission and distribution
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft for
Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of which
they are aware and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some Countries”
clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for
submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
Amendment 1 - Instrument transformers - Part 9: Digital interface for instrument transformers

PROPOSED STABILITY DATE: 2029
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.

IEC CDV 61869-9/AMD1 © IEC 2026
1 CONTENTS
3 INTRODUCTION . 3
4 Normative references . 4
5 Terms and definitions . 5
6 List of terms and definitions is extended with . 5
7 Clipping . 5
8 Index of abbreviations . 5
9 6.904.1 General . 5
10 6.903.2 Variants . 5
11 6.903.4 Logical Devices . 6
12 6.903.7 Logical nodes TCTR . 7
13 6.903.8 Logical nodes TVTR . 9
14 6.903.9 Quality . 11
15 6.904.1 Dataset(s) . 11
16 6.903.11 Multicast sample value control block . 12
17 6.903.13 Rated conformance classes . 13
18 6.904 Synchronization . 14
19 6.904.1 General . 14
20 6.904.2 Precision Time Protocol Synchronization . 14
21 6.904.4 Sample value message SmpSynch attribute . 14
22 6.904.5 Holdover mode . 15
23 6.904.6 Free-running mode . 16
24 6.904.7 Time adjustments . 16
25 7.2.903 Loss of synchronization tests . 19
26 F.1 Grandmaster election test . 84
27 F.2 Loss of synchronization tests . 84
28 F.3 Global synchronization restoration test (SmpSynch 0 to 2 transition) . 84
29 F.4 Local synchronization restoration test (SmpSynch 0 to 1 transition) . 85
30 F.5 Synchronization source switching test (SmpSynch 1 to 1 or 1 to 2) . 85
31 Bibliography . 88
33 Figure 908 – TCTR naming example . 8
34 Figure 910 – Time adjustment example (6 ASDU example) . 17
35 Figure 911 – Slew based time adjustment example (2 ASDU, free running to global) . 18
36 Figure 912 – Slew based time adjustment example (2 ASDU, local to global) . 18
37 Figure 9F1 – Step based time adjustment induced error example . 86
38 Figure 9F2 – Slew based time adjustment angle behaviour example . 87
IEC CDV 61869-9/AMD1 © IEC 2026
42 INTERNATIONAL ELECTROTECHNICAL COMMISSION
43 ____________
45 INSTRUMENT TRANSFORMERS
47 Part 9: Digital interface for instrument transformers
49 This amendment has been prepared by IEC technical committee 38: INSTRUMENT
50 TRANSFORMERS. It is the amendment 1 to International Standard IEC 61869:2016.
51 This edition includes the following significant technical changes with respect to the previous
52 edition:
53 a) Alignment to IEC 61850-9-2:2011+AMD1:2020 introducing the SynchSrcID information in
54 the SV stream indicating the active time synchronisation source of the MU
55 b) Addition of a slew based synchronisation mechanism with associated requirements
56 The text of this amendment is based on the following documents:
Draft Report on voting
XX/XX/FDIS XX/XX/RVD
58 Full information on the voting for its approval can be found in the report on voting indicated in
59 the above table.
60 The language used for the development of this amendment is English.
61 This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
62 accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
63 at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
64 described in greater detail at www.iec.ch/publications.
65 The committee has decided that the contents of this document will remain unchanged until the
66 stability date indicated on the IEC website under webstore.iec.ch in the data related to the
67 specific document. At this date, the document will be
68 • reconfirmed,
69 • withdrawn,
70 • replaced by a revised edition, or
71 • amended.
IEC CDV 61869-9/AMD1 © IEC 2026
73 INTRODUCTION
74 In the enumeration introduced by "The IEC 61869-9 standard:" add a dash
75 – amendment 1 adds the optional SynchSrcID information in the SV stream indicating the
76 active time synchronisation source of the MU in order to align to IEC 61850 series edition
77 2.1 and IEC 61850-9-2:2011+AMD1:2020.
78 – amendment 1 updates and clarifies the step-based synchronization mechanism.
79 – amendment 1 also adds a slew-based synchronisation mechanism with associated
80 requirements.
IEC CDV 61869-9/AMD1 © IEC 2026
102 INSTRUMENT TRANSFORMERS
104 Part 9: Digital interface for instrument transformers
108 2 Normative references
109 Replace the text of the whole clause by the following:
110 The following documents, in whole or in part, are normatively referenced in this document and
111 are indispensable for its application. For dated references, only the edition cited applies. For
112 undated references, the latest edition of the referenced document (including any amendments)
113 applies.
114 Clause 2 of IEC 61869-6:2016 is applicable with the following additions:
115 IEC 61588:2021, Precision clock synchronization protocol for networked measurement and
116 control systems
117 IEC 61850-6:2009+AMD1:2018+AMD2:2024, Communication networks and systems for power
118 utility automation – Part 6: Configuration description language for communication in electrical
119 substation related to IEDs
120 IEC 61850-7-1:2011+AMD1:2020, Communication networks and systems for power utility
121 automation – Part 7-1: Basic communication structure − Principles and models
122 IEC 61850-7-2:2010+AMD1:2020, Communication networks and systems for power utility
123 automation – Part 7-2: Basic information and communication structure – Abstract
124 communication service interface (ACSI)
125 IEC 61850-7-3:2010+AMD1:2020, Communication networks and systems for power utility
126 automation – Part 7-3: Basic communication structure – Common data classes
127 IEC 61850-7-4:2010+AMD1:2020, Communication networks and systems for power utility
128 automation – Part 7-4: Basic communication structure – Compatible logical node classes and
129 data object classes
130 IEC 61850-8-1:2011+AMD1:2020, Communication networks and systems for power utility
131 automation – Part 8-1: Specific communication service mapping (SCSM) – Mappings to MMS
132 (ISO 9506-1 and ISO 9506-2) and to ISO/IEC 8802-3
133 IEC 61850-9-2:2011+AMD1:2020, Communication networks and systems for power utility
134 automation – Part 9-2: Specific communication service mapping (SCSM) – Sampled values over
135 ISO/IEC 8802-3
136 IEC 61850-10:2012, Communication networks and systems for power utility automation – Part
137 10: Conformance testing
138 IEC 61869-6:2016, Instrument transformers – Part 6: additional general requirements for low
139 power instrument transformers
140 IEC 61850-9-3:2016, Communication networks and systems for power utility automation – Part
141 9-3: Precision time protocol profile for power utility automation
IEC CDV 61869-9/AMD1 © IEC 2026
143 3 Terms and definitions
144 List of terms and definitions is extended with
145 3.5.905
146 Clipping
147 a form of limiting in which all the instantaneous values of a signal exceeding a predetermined
148 threshold value are reduced to values close to that of the threshold, all other instantaneous
149 values of the signal being preserved.
150 Source: IEV 702-04-33
151 3.6 Index of abbreviations
152 Index of abbreviations is extended with
153 PTP Precision time protocol specified in IEC 61588
154 5.901 Performance requirements
155 Replace the text of the fifth paragraph with
156 For example, when powering up, an optical current transformer may need to activate
157 thermoelectric coolers, perform carefully controlled laser start-up, and wait until the system has
158 stabilized to allow operation within stated accuracy. During this process, merging unit (digital)
159 output should be disabled. If data output is enabled, quality and validity attributes associated
160 with all affected data values shall be tagged as ‘invalid’ in accordance with 6.903.9. The same
161 requirement applies during power-down (loss of power) and self-diagnostic system activation
162 (i.e. DSP subsystem failure). The merging unit should guarantee no un-flagged bad sampled
163 value data is sent out.
164 6.903 Specification of the communications profile
165 6.903.1 General
166 In the second sentence replace “IEC 61850-9-2:2011” by “IEC 61850-9-2”
167 6.903.2 Variants
168 Replace the text in the whole subclause with
169 To facilitate interoperability, only a limited variability is permitted for naming, message
170 structure, sample rate, analogue signal content and scaling. The permitted variants are
171 described in the device nameplate using the following notation, introduced here as an easy way
172 to describe merging unit capabilities in a human readable text format:
173 F f S s I i U u
174 where
175 f is the digital output sample rate expressed in samples per second
176 s is the number of ASDUs (samples) contained in a sampled value message
177 i is the number of current quantities contained in each ASDU
178 u is the number of voltage quantities contained in each ASDU.
IEC CDV 61869-9/AMD1 © IEC 2026
179 Device nameplate documents device capability (range of supported variants) with active
180 configuration separately specified in the merging unit configuration file (Annex 9C).
181 Variant notation examples:
182 F4000S1I4U4 describes the 9-2LE MSVCB01 sampled values with 50 Hz nominal system
183 frequency.
184 F12800S8I4U4 describes the 9-2LE MSVCB02 sampled values with 50 Hz nominal
185 system frequency.
186 F4800S2I8U0 describes sampled values with 4800 samples per second, two ASDU (samples)
187 per message, 8 currents, and no voltages.
188 Instrument transformers / MU claiming compliance to this standard shall be configurable to
189 implement at least one of the preferred rates defined in Table 902 and at least one of the
190 following backward compatible configurations:
191 F4000S1I4U4
192 F4800S1I4U4
193 F5760S1I4U4
194 The backward compatibility requirement does not apply to merging units for DC applications,
195 UCA 9-2LE Power Quality applications, and merging units intended for special purpose
196 applications.
197 Merging units may also implement variants with other number of currents and voltages. The
198 minimum number of current plus voltage quantities allowed is 1. It is recommended that the
199 maximum number of quantities allowed on a 100 Mbit/s network be limited to:
200 for general measuring and protection: 24 quantities
201 for quality metering: 8 quantities
202 for DC control applications: 24 quantities.
203 The maximum limitations are introduced to ensure fair network access and prevent blocking
204 caused by excessively long Ethernet frames. No specific limits are defined for 1 Gbit/s and
205 faster networks or applications where the MU is directly connected (point-to-point) to a higher
206 speed backbone bridge. DC instrument transformer outputs may require point to point
207 connection and Gigabit Ethernet links.
208 6.903.4 Logical Devices
209 Replace the text in the whole subclause by the following
210 The merging unit shall implement one or more logical devices. Logical devices shall be as
211 specified in IEC 61850-7-2.
212 Each logical device product-related name (LDName), hosting a 9-2LE multicast sampled value
213 control block (MSVCB01 or MSVCB02) and dataset (PhsMeas1) shall be preconfigured as
214 follows:
215 xxxxMUnn
IEC CDV 61869-9/AMD1 © IEC 2026
216 where
217 xxxx is the configurable IED name of the merging unit per IEC 61850-6.
218 MUnn is the logical device instance name, the attribute “inst” of the element LDdevice in the IED section of the
219 ICD file. nn shall be a decimal number that makes the instance identifier of the logical device unique within the
220 physical device.
221 NOTE 902 The combination of the IED name and the LD instance number makes the logical device unique within
222 the system.
223 6.903.7 Logical nodes TCTR
224 Replace the text of the whole subclause by the following:
225 TCTR logical nodes shall be as specified in IEC 61850-7-4, except that the TCTR logical nodes
226 shall be extended by the addition of the nameplate data objects defined in Table 905 and in
227 Table 903. The value of TCTR.NamPlt.InNs shall be “IEC 61869-9:2016”. The values of the
228 data attributes of these extended data objects shall be read-only.
229 Each TCTR name (LNName) shall be formatted during engineering phase according to:
230 I nn p TCTR n
231 where
232 nn is the instance number of the current measurement point (01-99) that makes the current
233 measurement identification (Inn) unique within the bay. This value is part of the
234 substation section of the SCL description and is defined during the engineering process.
235 p is the phase identification of the primary current, either A, B, C, or N for a.c. instrument
236 transformers. For d.c. instrument transformers, pending support for d.c. systems in the
237 IEC 61850 series of standards, use A for the pole 1, B for the pole 2, and N for earth
238 return. This value should correspond to the SubEquipment phase attribute in the
239 substation section of the SCL description if any.
240 n is the attribute “inst” of the element LN in the substation and IED sections of the ICD
241 file. It binds the TCTR described in the substation section to the TCTR described in the
242 IED section. “n” shall be a decimal number (0 through 99).
243 TCTR name shall be unique within the logical device and is in general configurable or fixed by
244 the manufacturer.
245 As an example, a TCTR name might be:
246 I02ATCTR4
247 The above name is for current measurement point number 02, phase A, with current transformer
248 core connected to TCTR instance 4 as illustrated in Figure 908. This is only one example
249 illustrating substation modelling defined in IEC 61850-7-1 and substation configuration
250 language rules defined in IEC 61850-6.
IEC CDV 61869-9/AMD1 © IEC 2026
I02ATCTR4 I02ATCTR1 I01ATCTR7
A
B
C
Measurement Measurement
point 02 point 01
TCTR1 TCTR7
TCTR2
TCTR8
TCTR3 TCTR9
TCTR4
TCTR5
Logical Device
TCTR6
MU01
252 Figure 908 – TCTR naming example
253 It is recommended to map the TCTR logical node in the substation section (Equipment
254 (instrument transformer) / SubEquipment (Phase)) to define and identify the measuring point in
255 accordance with IEC 61850-6.
256 The TCTR data object NamPlt shall conform to the LPL common data class definition in
257 IEC 61850-7-3.
258 When user is allowed to edit the prefix, prefix shall retain the deployed phase information.
259 The TCTR data object AmpSv shall conform to the SAV common data class definition in
260 IEC 61850-7-3. The attributes AmpSv.instMag.i, AmpSv.sVC.scaleFactor, AmpSv.sVC.offset,
261 AmpSv.units.multiplier and AmpSv.units.SIUnit shall be mandatory and read-only with values
262 specified in Table 904:
263 Table 904 – AmpSv object attribute values
Attribute Value
AmpSv.units.SIUnit 5 (code for ampere)
AmpSv.units.multiplier 0
AmpSv.sVC.offset 0
AmpSv.sVC.scaleFactor 0,001
AmpSv.instMag.i count (of milliampere)
265 All current measurements are scaled to reflect primary current values and are transmitted using
266 signed 32 bit integer format.
IEC CDV 61869-9/AMD1 © IEC 2026
267 Neutral current can be measured directly. If a direct measurement of this value is not available,
268 it is acceptable to substitute an estimate computed by creating an algebraic sum of currents
269 flowing through all live conductors in accordance with IEC 61850-7-3. This quantity shall use
270 the same scaling as defined in Table 904. The derived bit defined in 9-2 LE guideline is not
271 used.
272 IN = IA + IB + IC
273 This equation does not necessarily apply for distribution networks with impedance grounded
274 neutral point and distributed neutral. Equation used in that case needs to be user defined. See
275 IEC 61850-7-3:2010+AMD1:2020, Figure 16.
276 Available options for publication of the neutral current and its accuracy shall be described in
277 the product documentation.
278 Table 905 – Extensions to the TCTR class
TCTR class extensions with nameplate information
Data object Common Explanation T M/O/C
name data class
VSD the accuracy class rating in the format described in clause 5.6, M
NamAccRtg
e.g. “0,5S/5P20”
VSD M
NamARtg
a semicolon separated list of the rated primary currents (IPr) in amperes, e.g.
“200;400;800”
VSD the ratio of the clipping limit of the instantaneous current to the rated primary M
NamClipRtg
current multiplied with a square root of two, e.g. “20”
Key
M = Mandatory
O = Optional
C = Conditional
280 6.903.8 Logical nodes TVTR
281 Replace the text of the whole subclause by the following:
282 TVTR logical nodes shall be as specified in IEC 61850-7-4, except that the TVTR logical nodes
283 shall be extended by the addition of the nameplate data objects defined in Table 907. The
284 value of TVTR.NamPlt.lnNs shall be “IEC 61869-9:2016”. The values of the data attributes of
285 these extended data objects shall be read-only.
286 Each TVTR name (LNName) shall be formatted during engineering phase according to:
287 U nn pTVTR n
288 where
289 nn is the instance number of the voltage measurement point (01-99) that makes the voltage
290 measurement identification (Unn) unique within the bay. This value is part of the
291 substation section of the SCL description.
292 p is the phase identification, either A, B, C, AB, BC, CA or N for a.c. instrument
293 transformers. For d.c. instrument transformers, pending support for d.c. systems in the
294 IEC 61850 series, use A for the pole 1, B for the pole 2, and N for earth return. This
295 value should correspond to the SubEquipment phase attribute in the substation section
296 of the SCL description if any.
297 n is the attribute “inst” of the element LN in the substation and IED sections of the ICD
298 file. It binds the TVTR described in the substation section to the TVTR described in the
299 IED section. "n" shall be a decimal number (0 through 99).
IEC CDV 61869-9/AMD1 © IEC 2026
300 TVTR name shall be unique within the logical device and is in general configurable or fixed by
301 the manufacturer.
302 As an example, a TVTR name might be:
303 U01ATVTR1
304 It is recommended to map the TVTR logical node in the substation section (Equipment
305 (instrument transformer) / SubEquipment (Phase)) to define and identify the measuring point in
306 accordance with IEC 61850-6.
307 The TVTR attribute NamPlt shall conform to the LPL common data class definition in
308 IEC 61850-7-3.
309 When user is allowed to edit the prefix, prefix shall retain the deployed phase information.
310 The TVTR data object VolSv shall conform to the SAV common data class definition in
311 IEC 61850-7-3, except that attributes VolSv.instMag.i, VolSv.sVC.scaleFactor,
312 VolSv.sVC.offset, VolSv.units.multiplier and VolSv.units.SIUnit are mandatory and read -only
313 with values specified in Table 906:
314 Table 906 – VolSv object attribute values
Attribute Value
VolSv.units.SIUnit 29 (code for volt)
VolSv.units.multiplier 0
VolSv.sVC.offset 0
VolSv.sVC.scaleFactor 0,01
VolSv.instMag.i count (of centivolt)
316 All voltage measurements are scaled to represent primary voltage values and are transmitted
317 using signed 32 bit integer format.
318 Neutral voltage can be measured directly or derived based on individual phase to ground
319 measurements. When derived, VN shall be equal to a simple arithmetic sum of the phase to
320 ground voltages and shall use the same scaling as defined in Table 906. Derived bit defined in
321 9-2 LE guideline is deprecated.
322 VN = VA + VB +VC
323 Available options for publication of the neutral voltage and its accuracy shall be described in
324 the product documentation.
325 Table 907 – Extensions to the TVTR class
TVTR class extensions with nameplate information
Data object Common Explanation T M/O/C
name data class
NamAccRtg VSD the accuracy class rating in the format described in clause 5.6, e.g. “0.5/3P” M
VSD the rated primary voltage (U ) in volts, e.g. for rating of 300000/sqrt(3) we will M
NamVRtg
Pr
have “173000”
VSD the ratio of the clipping limit of the instantaneous voltage to the rated primary M
NamClipRtg
voltage multiplied with a square root of two, e.g. “2”
Key
M = Mandatory
O = Optional
IEC CDV 61869-9/AMD1 © IEC 2026
TVTR class extensions with nameplate information
Data object Common Explanation T M/O/C
name data class
C = Conditional
327 6.903.9 Quality
328 Replace the text of the third paragraph with
329 The quality of each sampled value (TCTR.AmpSv.q, TVTR.VolSv.q) in each ASDU shall be as
330 represented by its quality value in that ASDU. For example, if a channel having previously been
331 accurate becomes inaccurate, the first inaccurate value shall have in the same ASDU its validity
332 attribute set to questionable and detail quality attribute inaccurate set to true.
333 Replace the text of the fifth paragraph with
334 The validity attribute shall be set to questionable and the outOfRange quality data attribute shall
335 be true (q.validity = questionable and q.detailQual.outofRange = true) for samples affected by
336 clipping. outOfRange attribute shall not be set for situations other than clipping.
337 Replace the text of the eighth paragraph with
338 The inaccurate quality data attribute (q.validity = questionable and q.detailQual.inaccurate =
339 true) shall be true when an instrument transformer supervision function has detected an error
340 condition indicating that the sampled value output does not meet the nameplate measuring
341 accuracy class but may be useable for other applications. Simultaneously setting the inaccurate
342 attribute to true for all analogue data values is used to indicate time synchronization event as
343 specified in section 6.904 while tagged as inaccurate, measurement error should not exceed
344 two times the stated protection accuracy class or 2% at rated input level in case protection
345 accuracy class is not defined.
346 Table 907.1 – Quality attribute summary
State q.validity q.detailQual Remarks
Normal operation good Default Data meets all stated accuracy
(FALSE) specifications
Clipping questionable outOfRange True on the affected channel
Data may be used for protection
Data does not meet the questionable inaccurate True on the affected channel
stated measuring
Data may be used for protection
accuracy specification
Time synchronization in questionable inaccurate Simultaneously set true on all
progress valid channels.
Data may be used for protection
Quantity not present or invalid Default True on the affected channel
logical node is OFF (FALSE)
Mode / behaviour support
Diagnostic failure invalid failure Data is unusable
347 6.903.10  Dataset(s)
348 Replace the text of the whole subclause by the following:
349 The datasets shall be as specified in IEC 61850-7-2, and as further constrained by this
350 subclause 6.903.10.
IEC CDV 61869-9/AMD1 © IEC 2026
351 Dataset members shall consist of AmpSv.instMag.i (current sampled value) or VolSv.instMag.i
352 (voltage sampled value) attributes, each followed immediately by the corresponding AmpSv.q
353 or VolSv.q (quality) data attribute. The number of current sampled values and the number of
354 voltage sampled values shall match the number of each specified by the variant code for the
355 dataset.
356 All AmpSv members (current sampled values) shall precede any VolSv members (voltage
357 sampled values).
358 Each dataset name (DSName) declared to be 9-2LE backward compatible configuration shall
359 be configured according to:
360 PhsMeas1
361 The dataset name PhsMeas1 shall only be used for a 9-2LE datasets whose members in order
362 are:
363 InnATCTR1.AmpSv.instMag.i
364 InnATCTR1.AmpSv.q
365 InnBTCTR2.AmpSv.instMag.i
366 InnBTCTR2.AmpSv.q
367 InnCTCTR3.AmpSv.instMag.i
368 InnCTCTR3.AmpSv.q
369 InnNTCTR4.AmpSv.instMag.i
370 InnNTCTR4.AmpSv.q
371 UnnATVTR1.VolSv.instMag.i
372 UnnATVTR1.VolSv.q
373 UnnBTVTR2.VolSv.instMag.i
374 UnnBTVTR2.VolSv.q
375 UnnCTVTR3.VolSv.instMag.i
376 UnnCTVTR3.VolSv.q
377 UnnNTVTR4.VolSv.instMag.i
378 UnnNTVTR4.VolSv.q
379 6.903.11    Multicast sampled value control block
380 Replace the text of the whole subclause by the following:
381 The multicast sampled value control blocks shall be as specified in IEC 61850-7-2, and as
382 further constrained by this subclause. The value of attribute MsvID shall be unique within the
383 substation. It is recommended that this field be short to preserve communications bandwidth
384 (recommend making it equal to hexadecimal character representation of APPID: 4000 to 7FFF).
385 NOTE 903 Some legacy devices restrict the length of this field to be between 10 and 34 characters.
386 In the context of IEC 61850-9-2 the APPID value of 0x4000 mandated by the UCA 9-2LE
387 Guideline indicates the lack of configuration. IEC 61850-9-2 strongly recommends having a
388 unique, source orientated SV APPID within a system, to enable a filter on the link layer.
389 The SmpMod attribute shall have a value of “1” (samples per second). The SmpRate attribute
390 shall have a value matching the sample rate in the variant code for the control block with the
391 exception of d.c. control block for 96 kHz where the value is 9600. Use of 9600 samples per
392 nominal period (smpMod = 0), implying a nominal frequency of 10 Hz, is a workaround to the
IEC CDV 61869-9/AMD1 © IEC 2026
393 maximum value the SmpRate attribute can encode. The OptFlds.refresh-time attribute shall be
394 as configured. Control block for 96 kHz d.c. applications exposed in SCL based configuration
395 file shall use the full value “96000”.
396 The OptFlds.reserved (OptFlds.samplesynchonised in IEC 61850-9-2) attribute shall be true.
397 The OptFlds.sample-rate attribute shall be false.
398 The OptFlds.data-set-name attribute shall be false.
399 The OptFlds.security attribute as per IEC 61850-9-2 shall be false if IEC 62351-6 is not used,
400 otherwise refer to IEC 62351-6.
401 The smpMod attribute shall not be present in the SV message.
402 The noASDU attribute shall have a value matching the number of ASDUs in the applicable
403 variant code defined in 6.903.2.
404 The OptFlds.synch-source-identity attribute shall be supported and configurable for all MU
405 supporting time synchronization over IEC 61850-9-3.
406 Each multicast sampled value control block name (MsvCBName) declared to match 9-2LE
407 backward compatible configuration shall be preconfigured as follows:
408 MSVCB01
409 MSVCB02
410 where
411 In the control blocks MSVCB01, MSVCB02, the SmpMod attribute shall have a value of ‘0’
412 (samples per nominal period).
413 For control blocks MSVCB01 SmpRate attribute shall be 80, and for MSVCB02 it shall be 256.
414 The OptFlds.refresh-time attribute shall be false.
415 The OptFlds.reserved (OptFlds.samplesynchonised in IEC 61850-9-2) attribute shall be true.
416 The OptFlds.sample-rate attribute shall be false.
417 The OptFlds.data-set-name attribute shall be false.
418 The OptFlds.security attribute as per IEC 61850-9-2 shall be false.
419 The smpMod attribute shall not be present in the SV message.
420 The noASDU attribute shall have a value matching the number of ASDUs in the applicable
421 variant code defined in 6.903.2.
422 The OptFlds.synch-source-identity attribute shall be false.
423 6.903.13 Rated conformance classes
424 Replace the text of the whole clause by the following:
425 The standards of the IEC 61850 series specify a large set of communication models and
426 services. Not all of these are necessary in merging units; but capabilities such as MMS based
427 configuration, test and supervision of a merging unit are strongly recommended. IEC 61850-7-
IEC CDV 61869-9/AMD1 © IEC 2026
428 2:2010+AMD1:2020, Annex A. contains a detailed description showing how to generate the
429 conformance statement describing applicable device capabilities.
431 Clauses 6.903.13.1 through 6.903.13.6 are deleted in favour of IEC 61850-7-
432 2:2010+AMD1:2020, Annex A.
433 6.904 Synchronization
434 6.904.1 General
435 In the fifth paragraph replace “IEC 61850-9-2:2011” by “IEC 61850-9-2”
436 6.904.2 Precision Time Protocol Synchronization
437 Replace the text of the third paragraph with
438 As defined in 6.904.4, the SmpSynch value is set according to the estimated synchronization
439 accuracy of the MU toward the globally traceable grandmaster. To estimate this information,
440 the clockAccuracy field value of the active grandmaster shall be used.
441 NOTE According to IEC 61850-9-3 global traceability is assumed when receiving a specified clockAccuracy <= 0x30
442 (accuracy is within 10s) value from an IEC 61850-9-3 conformant clock. For the merging unit applications accuracy
443 must be much better.
444 Grandmaster clock with clockAccuracy better or equal to 250 ns shall be accepted with
445 SmpSynch value set to 2 identifying it as a global clock. Any other synchronization signal shall
446 be considered as a local clock. Although dedicated clocks are preferred, merging unit with a
447 high-quality oscillator is allowed to implement the PTP grandmaster functionality in accordance
448 with IEC 61850-9-3. Such functionality shall be configurable and disabled by default.
449 NOTE According to IEC 61850-9-3 published clock accuracy of 250 ns means that end devices can be synchronized
450 to within 1µs once network propagation inaccuracy is accounted for.
451 Relation between the PTP clockAccuracy and the MU SmpSynch field is shown in table 909.
452 Table 909 – Relation between clockAccuracy and SmpSynch
Required PTP SmpSynch Synchronized MU
ClockAccuracy
≤ 250 ns (0x20 to 0x22) 2 Global
> 250 ns (≥ 0x23) 1 Local
No PTP clock available 0 Free Running
454 NOTE Table 909 assumes stationary conditions which do not apply while the synchronization is in progress.
456 6.904.4 Sample value message SmpSynch attribute
457 Replace the text of the whole subclause by the following
458 Applications that are sensitive to the phase angle difference between different merging units
459 require that the sampled values from those merging units be synchronized with each other.
460 Such applications include protection, metering, and synchrophasors. Sampled values are
461 synchronized to each other when each is synchronized to the same time source that fulfils the
462 clock accuracy requirements. The SmpSynch attribute defined in IEC 61850-9-
IEC CDV 61869-9/AMD1 © IEC 2026
463 2:2011+AMD1:2020, Table 14, provides information on the time source used to assist sample
464 value subscribers in determining whether sampled values are synchronized to each other.
465 See also IEC 61850-9-2:2011+AMD1:2020 clause 9. While locked to a PTP source
466 SynchSrcID attribute published by the merging unit shall match the gmIdentity field received
467 from that source. The value of gmIdentity shall be the network order of the bytes representing
468 grandmasterIdentity according to 13.5 of IEC 61588:2009.
469 While sampled values are synchronized to a global time reference to the degree required to
470 meet the measuring accuracy class phase error limit, the value of the "SmpSynch" attribute in
471 the SV messages shall be 2. The SmpSynch value of 2 (global) shall be reported by the MU
472 and based on the synchronization information received from the active time synchronization
473 source. A global area clock is a source that provides time that is traceable to the international
474 standards laboratories maintaining clocks that form the basis for the International Atomic Time
475 (TAI) and Universal Coordinated Time (UTC) timescales. Examples of these are Global
476 Navigation Satellite System (GNSS), and national standard institute timeservers. All sampled
477 values synchronized to any global area clock are synchronized to each other.
478 While sampled values are synchronized to a local area clock to the degree required to meet the
479 measuring accuracy class phase error limit, the value of the "SmpSynch" attribute in the SV
480 messages shall be 1. A local clock is a source that provides time that advances at essentially
481 the correct rate but which may have a time offset from global time reference and other local
482 area clocks. A specific local area clock unique identifier is the gmIdentity contained in the active
483 time synchronization signal. The identifier of the active synchronization source shall be
484 published using the attribute SynchSrcID (see in IEC 61850-9-2:2011+AMD1:2020, Table 14),
485 based on the corresponding information contained in the active time synchronization signal .
486 All sampled values synchronized to the same local area clock are synchronized to each other
487 but may not be synchronized to sampled values synchronized to another clock. The meaning of
488 unspecified local area clock code (SmpSynch == 1 with no SynchSourceID) depends on the
489 design of the time distribution network. In cases where the time distribution network design
490 ensures that a set of merging units can only receive synchronization from the same local area
491 clock merging units are synchronized to each other.
492 Network design which allows different merging units to receive the synchronization signal from
493 different local area clocks cannot ensure merging units are synchronized to the same time
494 reference. Output of such merging units should not be time aligned and used by the same
495 function.
496 While sampled values are not synchronized to a global or local area clock to the degree required
497 to meet the measuring accuracy class phase error limit, the value of the "SmpSynch" attribute
498 in the SV messages shall be 0 (“not synchronized”). A merging unit may be in the not
499 synchronized state due to:
500 • the synchronizing signal having never been received;
501 • the synchronizing signal being interrupted and the merging unit operating beyond its
502 holdover duration specification;
503 • lock to the synchronizing signal not acquired;
504 • other conditions that results in the samples not being synchronized with an external clock
505 to the degree required by the measuring accuracy class phase error limit.
507 6.904.5 Holdover mode
508 Replace the text of the whole subclause by the following:
509 When the external synchronization signal is lost, the merging unit shall go into a holdover mode.
510 For the duration of the holdover period the merging unit shall continue to send samples
511 maintaining the sample timing required for the measuring accuracy class. During holdover, the
512 "SmpSynch" and the SynchSrcID attributes in the SV messages shall remain unchanged, and
IEC CDV 61869-9/AMD1 © IEC 2026
513 the "SmpCnt" attribute in the SV messages shall increment and wrap as if a synchronization
514 signal were present.
515 The minimum holdover duration shall be 5 s under stable internal and external temperature
516 conditions. Minimum holdover time shall be defined in the device PICS statement and exposed
517 in the data model under TCTR.HoldTmms, TVTR.HoldTmms. Longer holdover time is
518 encouraged provided that the device can reliably estimate its worst-case drift and transitions to
519 free-running mode once the stated measurement accuracy class limit is exceeded.When the
520 synchronization signal resumes before holdover timeout, the sampled value messages shall
521 continue as if the synchronizing signal were continuous.
522 The clock instance associated with the merging unit is allowed to become a master
523 (grandmaster capable). Such PTP master shall meet all requirements outlined in IEC 61850-9-
524 3.
525 6.904.6 Free-running mode
526 Replace the second paragraph by the following
527 While free-running, the "SmpSynch" attribute in the SV messages shall be zero, and the
528 "SmpCnt" attribute in the SV messages shall increment and wrap as if a synchronization signal
529 were present. Since there is no GmIdentity that the merging unit can report at this time,
530 GmIdentity field defined in IEC 61850-9-2:2011+AMD1:2020 shall be generated internally
531 allowing the merging unit to publish a globally unique SynchSrcID. The SynchSrcID attribute
532 shall be based on the merging unit media access controller (MAC) address as defined in IEC
533 61588:2019 Clause 7.5.2.2.2.1.
534 6.904.7 Time adjustments
535 Replace the text of the whole subclause by the following:
536 When the merging unit external time synchronization signal is restored after an interruption, or
537 when a switch is made between different time sources, or when the external time source
538 executes a time adjustment, there may be an offset between the time tracked before the event
539 and the time tracked after the event. In this case a time adjustment of the merging unit local
540 clock that controls sample times is required.
541 For merging units capable of performing instantaneous sampling instant correction (i.e. using
542 sample time interpolation), the time adjustment shall be accomplished as follows. The sampling
543 instant shall jump from the old time to the new time between consecutive samples. The sample
544 interval over jumps shall be no more than one and a half times the nominal interval and no
545 shorter than one half times the nominal interval. SmpCnt is discontinuous over the jump for
546 time adjustments larger than are accommodated by an off-nominal sample interval but is always
547 continuous for samples immediately prior to the adjustment a
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