DKEnerginet

TR 3.3.1 — Technical Regulation for Energy Storage

127 grid connection requirements for non-synchronous BESS plants (Type C and D), organized by functional category. Each requirement is tagged with the equipment scope responsible for delivering it. Denmark operates in two synchronous areas — DK1 (Continental Europe) and DK2 (Nordic) — with different frequency control parameters in each.

Type categories (TR 3.3.1 §2)

Type A

Up to 125 kW

Type B

125 kW – 3 MW

Type C

3 – 25 MW

Type D

≥ 25 MW or ≥ 110 kV

PCSPPCProtectionInterfacesPQMSystemType D

Operating ranges

7 requirements

Requirement	Specification	Scope	Ref
Continuous frequency range	49.0–51.0 Hz	PCS
Extended frequency (30 min)	47.5–49.0 Hz and 51.0–51.5 Hz	PCS	§6
Continuous voltage range (≤ 1 kV)	0.85–1.10 × Un	PCS	§6
Continuous voltage range (> 1 kV)	0.90–1.10 × Uc	PCS	§31
RoCoF withstand	± 2 Hz/s	PCS
Phase jump withstand	Up to 20° transitory	PCS
Permissible P reduction at underfrequency	Up to 6% of Pn per Hz below 49 Hz	PCS	§12

Fault ride-through

6 requirements

UV-FRT profiles differ between distribution-connected (Type B/C) and transmission-connected (Type D/transmission) facilities, and between DK1 and DK2 synchronous areas for transmission connections.

Requirement	Specification	Scope	Ref
OV-FRT	1.20 × Uc for 5s, 1.15 × Uc for 60s	PCS
UV-FRT — distribution (Type B/C)	0.15 pu for 250 ms → 0.90 pu at 1.5s	PCS
UV-FRT — transmission DK1Type D	0.00 pu for 150 ms → 0.85 pu at 1.5s	PCS
UV-FRT — transmission DK2Type D	0.00 pu for 150 ms → 0.90 pu at 1.5s	PCS
Consecutive faults	New dip after recovery = new fault situation	PCS	§114
Successive faults beyond profile	Disconnection permitted if faults push beyond time limit	PCS	§114

Fast fault current (FFC)

5 requirements

Non-synchronous facilities must supply reactive fault current during voltage dips. Distribution-connected Type B/C use a single FFC profile; transmission-connected facilities have separate DK1 and DK2 profiles.

Requirement	Specification	Scope	Ref
FFC activation — distribution	Commence within 100 ms after voltage dip	PCS
FFC characteristic — distribution	Linear 0.9 → 0.5 Uc, tolerance ±20% of In	PCS	§115
FFC activation — transmission DK1Type D	Commence within 100 ms, linear 0.9 → 0.5 pu	PCS	§133
FFC activation — transmission DK2Type D	Commence within 100 ms, linear 0.9 → 0.5 pu	PCS	§134
Delayed exit from FRT state	100–500 ms configurable, default 250 ms for distribution	PCS

Post fault active power recovery

5 requirements

Requirement	Specification	Scope	Ref
PFAPR — Type B/C	Resume pre-fault P within 5s, ± 5% Pn tolerance	PCS
PFAPR gradient	Approximately constant gradient, within bounds	PCS	§117
PFAPR precision	± 5% of Pn	PCS	§117
Extended PFAPR — Type DType D	Resume pre-fault P within 5–20s (configurable, 1s steps)	PCS
Extended PFAPR max rampType D	≤ 25% Pn per second	PCS	§124

Active power control and frequency control

20 requirements

Requirement	Specification	Scope	Ref
Absolute power constraint function	Implemented within 10s of receipt, ≤ 2% Pn precision (1 min avg)	PPC
Power constraint resolution	≥ 1% of Pnl and Pno	PPC	§9
Ramp rate range	1–20% Pn/min, max 1 MW/s	PPC
Default ramp rate	Maximum gradient	PPC	§32
Connection gradient	20% Pn/min, max 1 MW/s	PPC
LFSM-O — DK1	Breakpoint 50.20 Hz, droop 5%, range 2–12%	PPC
LFSM-O — DK2	Breakpoint 50.50 Hz, droop 4%, range 2–12%	PPC	§23
LFSM-O timing	Commence ≤ 2s, fully supplied within 30s	PPC	§23
LFSM-O precision	≤ 5% Pn (1 min avg), sensitivity ≤ 10 mHz	PPC	§23
LFSM-O island detection delay	500 ms before downward adjustment (distribution)	PPC	§23
LFSM-U — DK1	Breakpoint 49.80 Hz, droop 5%, range 2–12%	PPC
LFSM-U — DK2	Breakpoint 49.50 Hz, droop 4%, range 2–12%	PPC	§52
LFSM-U timing	Commence ≤ 2s, fully supplied within 30s	PPC	§52
LFSM-U disconnect (cannot reverse)	DK1: 49.00 Hz, DK2: 48.80 Hz	PPC	§52
FSM band — DK1	49.80–50.20 Hz	PPC	§53
FSM band — DK2	49.50–50.50 Hz	PPC	§53
FSM droop	2–12% in 1 pp steps	PPC	§53
FSM active power range	1.5–10% of Pn as minimum	PPC	§53
FSM sensitivity	≤ 10 mHz	PPC	§53
Auto connection within FSM band	≥ 3 min after voltage returns to normal range	PPC	§7

Reactive power and voltage control

11 requirements

Type C requires Q control, PF control, and voltage control. The relevant system operator specifies which control function is activated and the specific settings.

Requirement	Specification	Scope	Ref
Q control — setpoint response	Applied within 2s, complete within 30s	PPC
Q control — precision (Type C)	± 3% of Qn (1 min avg), 100 kvar resolution	PPC	§55
Q control — precision (transmission)Type D	5 MVAr or 5% Qn (lesser), same for resolution	PPC	§130
PF control — setpoint response	Applied within 2s, complete within 30s	PPC	§56
PF control — precision (Type C)	± 3% of Qn, resolution 0.01	PPC	§56
Voltage control — step response	90% within 1s, 100% within 5s	PPC
Voltage control — droop	2–7%, resolution 0.5%	PPC	§57
Voltage control — deadband	± 5% of Uref, step ≤ 0.5% Uref, symmetrical	PPC	§57
Voltage control — precision	± 3% of Qn (1 min avg)	PPC	§57
Infrastructure Q compensation	Compensate facility reactive power when disconnected/idle	System	§54
Units out for service	Q may be reduced pro rata with units out of operation	System	§38

System protection

4 requirements

Requirement	Specification	Scope	Ref
System protection levels	5 levels: 70%, 50%, 40%, 10%, 0% of rated power	Protection
Activation time	Begin within 1s, fully effected within 10s	Protection	§58
0% level	Without disconnection from electricity supply system	Protection	§58
Precision	≤ 1% of setpoint (1 min avg)	Protection	§58

Protection settings

11 requirements

Requirement	Specification	Scope	Ref
OV step 3 (Type C/D)	1.20 × Uc → 100 ms trip	Protection	§59
OV step 2	1.15 × Uc → 200 ms trip	Protection	§59
OV step 1	1.10 × Uc → 60s trip	Protection	§59
UV step 1	0.90 × Uc → 60s trip	Protection	§59
Overfrequency	51.5 Hz → 200 ms trip	Protection	§59
Underfrequency	47.5 Hz → 200 ms trip	Protection	§59
Rate of change of frequency	± 2.5 Hz/s → 80 ms trip	Protection	§59
Internal fault protection	Selective with grid protection, ≤ 100 ms trip for short circuits	Protection
Priority order	1. Grid/equipment → 2. Synthetic inertia → 3. Frequency control → 4. Power constraint → 5. Gradient	Protection	§26
Vector jump relays	NOT allowed as island protection	Protection	§25
Post-commissioning changes	DSO/Energinet may require protection setting changes	Protection	§24

Power quality

9 requirements

Requirement	Specification	Scope	Ref
DC current injection	< 0.5% of rated current	PQM	§14
Rapid voltage changes (≤ 33 kV)	d ≤ 4% of Un	PQM	§16
Rapid voltage changes (> 33 kV)	d ≤ 3% of Un	PQM	§16
Flicker — Type C/D	Per limits set by relevant system operator	PQM	§47
Harmonics — Type C/D	Per voltage limits set by relevant system operator	PQM	§48
Interharmonics — Type C/D	Per voltage limits set by relevant system operator	PQM	§49
2–9 kHz distortions — Type C/D	Per limits set by relevant system operator	PQM	§50
Three-phase balance (> 1 kV)	Must be balanced — no voltage unbalances	PQM	§40
PQ measurement standard	DS/EN 61000-4-30 (class A)	PQM	§22

Power oscillation damping (POD)

4 requirements

Type C non-synchronous facilities must be capable of power oscillation damping. This ensures converter-based BESS does not introduce or amplify oscillations in the grid.

Requirement	Specification	Scope	Ref
Oscillation limit	≤ ±0.5% of current power or ±0.25% of Pn (least restrictive)	PCS
Damping time	Within 180 seconds of exceeding limit	PCS	§121
Applicability	All voltages within normal and time-limited ranges	PCS	§121
After repeated incidents	Damped within 180s after last incident	PCS	§121

Information exchange and SCADA

12 requirements

Requirement	Specification	Scope	Ref
Basic signals (≥ 0.8 kW)	Stop signal, Hold signal in PCOM	Interfaces	§27
Logic interface	Input port for commands — can be controlled remotely	Interfaces	§27
Extended signals (≥ 1 MW)	CB status, P, Q, PF, control modes, setpoints — Table 20	Interfaces
Online communication (≥ 1 MW)	Real-time or periodic, UTC timestamps ±1 ms	Interfaces	§43
Type C additional signals	Planned P, voltage, V-control droop/status, system protection	Interfaces	§60
Type D additional signalsType D	Available P up/down, available Q up/down	Interfaces	§65
Measurement precision — MW	1.0% (Type C), 0.5% (Type D)	Interfaces	§43
Measurement precision — MVAr	2.0% (Type C), 1.0% (Type D)	Interfaces	§65
Measurement precision — kV	1.0% (Type C), 0.5% (Type D)	Interfaces	§65
IEC 61850 communication	Required for new exchanges; deadline may be extended	Interfaces
Setpoint logging (≥ 1 MW)	Record all changes + issuer, ≥ 100 changes, ≥ 3 months	Interfaces	§41
Timestamp precision	10 ms or less, referenced to UTC	Interfaces	§42

Fault incident recording

8 requirements

Requirement	Specification	Scope	Ref
Required measurements	Voltage, current, P, Q, frequency per phase + protection activations	PQM
Slow scan (3–25 MW)	50 Hz RMS, −10s to +60s	PQM	§62
Slow scan (≥ 25 MW)	50 Hz RMS, −10s to +60s	PQM	§62
Fast scan (10–25 MW)	≥ 1 kHz, −0.25s to +2.75s	PQM	§62
Fast scan (≥ 25 MW)	≥ 1 kHz, −3s to +60s	PQM	§62
Storage	≥ 3 months, up to 100 incidents	PQM	§62
Timestamp	UTC, ≤ 10 ms precision	PQM	§62
Format	COMTRADE, accessible to system operator on request	PQM	§41

Type D additional requirements

6 requirements

Type D adds island mode, quick re-synchronisation, simulation models, and authorised automatic connection on top of all Type C requirements.

Requirement	Specification	Scope	Ref
Automatic connection authorisationType D	Not permitted without system operator authorisation	PPC
Island mode capabilityType D	Operate within normal f/V ranges and FSM bands	PCS
Quick re-synchronisationType D	As instructed by system operator	PCS
Household operation (> 15 min re-sync)Type D	Self-sustained from any operating point, no external supply needed	PCS	§64b
Simulation modelsType D	Equivalent to NC RfG / NC DC requirements	System
Extended PFAPR optionType D	System operator chooses standard or extended PFAPR	PCS	§124

Compliance testing (non-synchronous Type C/D)

10 requirements

Product certificates from an approved certification body may substitute for any individual test. The relevant system operator may require additional tests beyond those listed here.

Requirement	Specification	Scope	Ref
1. LFSM-O	Frequency steps/ramps ≥ 10% Pmax change, droop verification	PPC	§142
2. Active power controllability	Demonstrate operation below reference point per absolute constraint	PPC	§143
3. LFSM-U	Frequency steps/ramps ≥ 10% Pmax, starting at ≤ 80% of max	PPC	§143
4. FSM	Full frequency range, droop/deadband/sensitivity verification	PPC	§143
5. Frequency restoration control	Demonstrate cooperation between FSM and frequency restoration	PPC	§143
6. Reactive power supply	Max Q at ind/cap, at >60%, 30–50%, and 10–20% power levels	System	§143
7. Voltage control	Droop, deadband, precision, rise time verification	PPC	§143
8. Q control	Range, rise, precision, response time	PPC	§143
9. Power factor control	Range, precision, reactive response to P step change	PPC	§143
Type D: same as Type C testsType D	All Type B + C compliance tests required	PPC	§144

Compliance simulation (non-synchronous Type C/D)

9 requirements

Requirement	Specification	Scope	Ref
LFSM-O simulation	Validate model against test, demonstrate compliance	System	§148
FFC simulation	Demonstrate fast fault current per FFC requirements	System	§148
UV-FRT / OV-FRT simulation	Demonstrate voltage fault tolerance	System	§148
PFAPR simulation	Demonstrate active power recovery after fault	System	§148
LFSM-U simulation	Validate model, demonstrate low-frequency response	System	§149
FSM simulation	Full frequency range, validate against tests	System	§149
Reactive power simulation	Validate model against reactive power tests	System	§149
POD simulation	Demonstrate power oscillation damping capability	System	§149
Type D: voltage fault toleranceType D	Model must demonstrate UV-FRT + OV-FRT compliance	System	§150

Grid connection permit process

Stage	Applies to	Details
Installation document	Type A	Location, date, max power, energy source, product certificates — submit to DSO
Facility document + declaration of conformity	Type B/C	Protection agreements, technical data, product certificates, simulation models, compliance test reports — DSO issues FON
EON (Energisation Operational Notification)	Type D	Permission to energise internal grid and auxiliary supplies via POC
ION (Interim Operational Notification)	Type D	Permission to operate and test for up to 24 months. Requires declaration of conformity, technical data, simulation models, test plans
FON (Final Operational Notification)	Type D	Full operational permit after all ION incompatibilities resolved. Updated models and test results with actual measured values
LON (Limited Operational Notification)	All (post-FON)	If significant modification or capacity loss lasts > 3 months. Max 12 months, suspends FON for affected requirements

Requirements based on Technical Regulation 3.3.1 Revision 6, published by Energinet (14 February 2025, English translation). Effective from 1 May 2025.