IEC TS 62786:2017

IEC TS 62786 ®
Edition 1.0 2017-04
TECHNICAL
SPECIFICATION
Distributed energy resources connection with the grid

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IEC TS 62786 ®
Edition 1.0 2017-04
TECHNICAL
SPECIFICATION
Distributed energy resources connection with the grid

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.01 ISBN 978-2-8322-4218-6

– 2 – IEC TS 62786:2017 © IEC 2017
CONTENTS
FOREWORD . 4
1 Scope and object . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Requirements on generating plants . 11
4.1 General . 11
4.2 Connection scheme . 12
4.3 Choice of switchgear . 12
4.3.1 General . 12
4.3.2 Interface switch . 12
4.4 Normal operating range . 12
4.4.1 General . 12
4.4.2 Operating frequency range . 12
4.4.3 Operating voltage range . 13
4.5 Immunity to disturbances . 13
4.5.1 General . 13
4.5.2 Rate of change of frequency (ROCOF) immunity . 13
4.5.3 Under voltage ride through (UVRT) requirements . 13
4.5.4 Over voltage ride through (OVRT) requirements . 14
4.6 Active power response to frequency deviation . 14
4.7 Reactive power response to voltage variations and voltage changes . 15
4.7.1 General . 15
4.7.2 Reactive power control . 15
4.7.3 Dynamic reactive power support capabilities . 15
4.8 EMC and power quality . 15
4.8.1 General . 15
4.8.2 Direct current (DC) injection . 16
4.9 Interface protection . 16
4.10 Connection and start to generate electrical power . 17
4.10.1 General . 17
4.10.2 Connection of synchronous generators . 17
4.10.3 Auto reclose of distribution lines . 17
4.11 Active power management . 18
4.12 Monitoring, control and communication . 18
4.12.1 Monitoring and control . 18
4.12.2 Communication . 18
5 Conformance tests . 18
Annex A (normative)  Operating frequency range . 19
Annex B (normative)  Operating voltage range . 20
Annex C (normative)  Under voltage ride through capability of DERs . 21
Annex D (normative)  Over voltage ride through parameters . 22
Bibliography . 23

Figure 1 – Electricity generating plant connected to a distribution network (schematic
view of switches) . 10
Figure 2 – Under voltage ride through capability requirements of DER . 14

Table 1 – Operating frequency requirements of DERs . 13
Table 2 – Operating voltage requirements of DERs . 13
Table 3 – Interface protection functions . 17
Table A.1 – Continuous operating frequency range . 19
Table A.2 – Limited operating frequency range . 19
Table B.1 – Continuous operating voltage range . 20
Table B.2 – Limited operating voltage range . 20
Table C.1 – UVRT capability of DERs with an interface to the grid based on a
synchronous generator . 21
Table C.2 – UVRT capability of DERs with an interface to the grid based on non-
synchronous generators (eg. converters, DFIG, etc.) . 21
Table D.1 – Medium voltage OVRT requirements . 22

– 4 – IEC TS 62786:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DISTRIBUTED ENERGY RESOURCES
CONNECTION WITH THE GRID
FOREWORD
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Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 62786 has been prepared by IEC Technical Committee 8: System aspects for
electrical energy supply.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
8/1439/DTS 8/1457/RVDTS
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directive
...