IEC TS 62786-3:2023

IEC TS 62786-3 ®
Edition 1.0 2023-11
TECHNICAL
SPECIFICATION
colour
inside
Distributed energy resources connection with the grid –
Part 3: Additional requirements for stationary battery energy storage
system
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IEC TS 62786-3 ®
Edition 1.0 2023-11
TECHNICAL
SPECIFICATION
colour
inside
Distributed energy resources connection with the grid –
Part 3: Additional requirements for stationary battery energy storage
system
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.01 ISBN 978-2-8322-7667-9
– 2 – IEC TS 62786-3:2023 © IEC 2023
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions, abbreviated terms and symbols . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms and symbols . 9
3.2.1 Abbreviated terms . 9
3.2.2 Symbols . 9
4 Requirements for distributed BESS . 11
4.1 General . 11
4.2 Connection scheme . 11
4.3 Choice of switchgear . 11
4.3.1 General . 11
4.3.2 Interface switch . 11
4.4 Normal operating range . 11
4.4.1 General . 11
4.4.2 Operating frequency range . 11
4.4.3 Operating voltage range . 12
4.5 Immunity to disturbances . 12
4.5.1 General . 12
4.5.2 Rate of change of frequency (ROCOF) immunity . 12
4.5.3 Under voltage ride through (UVRT) requirements . 12
4.5.4 Over voltage ride through (OVRT) requirements . 12
4.5.5 Rapid phase angle change immunity . 12
4.6 Active power response to frequency deviation . 13
4.6.1 General . 13
4.6.2 Active power response to over frequency . 14
4.6.3 Active power response to underfrequency . 14
4.7 Power response to voltage changes . 15
4.7.1 General . 15
4.7.2 Voltage support by reactive power . 15
4.7.3 Reactive power control modes . 15
4.7.4 Voltage related active power control . 15
4.7.5 Voltage related reactive power response . 16
4.7.6 Additional reactive current requirements on BESS . 16
4.8 EMC and power quality . 16
4.8.1 General . 16
4.8.2 Direct current (DC) injection . 16
4.9 Interface protection . 17
4.9.1 General . 17
4.9.2 Requirements on voltage and frequency protection . 17
4.9.3 Means to detect islanding situation . 17
4.9.4 Digital input to the interface protection . 17
4.10 Connection and starting to generate electrical power . 17
4.10.1 General . 17
4.10.2 Connection of BESS . 17
4.10.3 Auto reclose of distribution lines . 17

4.10.4 Black start capability and intentional islanding control . 17
4.11 Ceasing and reduction of active power on set point. 17
4.12 Remote information exchange . 17
4.12.1 General . 17
4.12.2 Monitoring and control . 18
4.12.3 Communication . 18
5 Conformance tests . 18
Annex A (normative) Operating frequency range . 19
Annex B (normative) Operating voltage range . 20
Annex C (normative) Summary of power thresholds to be defined by individual
countries . 21
Bibliography . 22

Figure 1 – Example of the interconnection interface concept . 8
Figure 2 – Typical power-frequency response curve for BESS charging and discharging

modes under operating frequency range . 13
Figure 3 – Example of reactive power capability range of BESS in per unit at nominal
voltage . 15
Figure 4 – Typical voltage related active power regulation of BESS . 16

Table 1 – Operating frequency requirements of BESS. 11
Table 2 – Operating voltage requirements of BESS with LV distribution network . 12
Table A.1 – Continuous operating frequency range . 19
Table A.2 – Limited operating frequency range . 19
Table A.3 – Limited charging/discharging time . 19
Table B.1 – Continuous operating POC voltage range . 20
Table B.2 – Limited operating voltage range . 20

– 4 – IEC TS 62786-3:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DISTRIBUTED ENERGY RESOURCES CONNECTION WITH THE GRID –

Part 3: Additional requirements for stationary
battery energy storage system
FOREWORD
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