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Grid Code/Finland/SJV2024
FIFingrid

SJV2024 — Finland Grid Code

161 grid connection requirements for BESS plants, organized by functional category. Each requirement is tagged with the equipment scope responsible for delivering it. Focus on Type C (10–30 MW) and Type D (≥30 MW or ≥110 kV).

Type categories (Table 3.1)

Type A
0.8 kW – 1 MW
Type B
1 – 10 MW
Type C
10 – 30 MW
Type D
≥ 30 MW or ≥ 110 kV
PCSPPCProtectionInterfacesPQMSystemType D

Operating ranges

6 requirements
RequirementSpecificationScopeRef
Continuous voltage rangeType D90–105% of nominalPCS§10.5.2
Continuous frequency range49.0–51.0 HzPCS§10.2.1
Extended frequency (30 min)47.5–49.0 Hz and 51.0–51.5 HzPCS§10.5.2
Extended voltage (60 min)105–110%PCS§10.5.2
RoCoF withstand≥ 2.0 Hz/sPCS§10.2.2
Phase jump withstand± 30° permanent vector shiftPCS§10.3.2

Fault ride-through

7 requirements
RequirementSpecificationScopeRef
Undervoltage FRT — Type B/C0.05 pu for 150 ms → 0.85 pu at 0.75s → 0.90 pu at 1.5sPCS§10.3.2
Undervoltage FRT — Type DType D0.00 pu for 200 ms → 0.85 pu at 0.75s → 0.90 pu at 1.5sPCS§10.5.3
Overvoltage withstand1.20 pu (3.5s) → 1.15 pu (5s) → 1.10 pu (10s)PCS§10.3.3
Overvoltage extendedType D1.10 pu for 60 min totalPCS§10.5.4
Applicable fault types3-phase, 2-phase, 2-phase-earth, 1-phase-earthPCS§10.3.2
Consecutive faultsMust ride through — no auto-disconnectPCS§10.3.2
Active power recoveryWithin 3 seconds to pre-fault level (± 5%)PCS§10.3.5

Reactive current supply (fault current)

7 requirements
RequirementSpecificationScopeRef
Default k-factor2.5 (configurable 2–6)PCS§10.3.4
Current priority during faultIq over Ip outside normal voltage rangePCS§10.3.4
Activation — undervoltage< 0.85 pu activate; > 0.90 pu deactivatePCS§10.3.4
Activation — overvoltage> 1.10 pu activate; < 1.05 pu deactivatePCS§10.3.4
Rise time to 90%30–50 msPCS§10.3.4
Target accuracy+20% / −10% within 80 msPCS§10.3.4
Negative sequence (asymmetric faults)Must supply in ratio defined by k-factorPCS§10.3.4

Grid-forming capability

11 requirements
Mandatory for Type C and D. Must operate constantly in grid-forming mode — not switchable. Active at all operating points, all charge states, production and demand modes.
RequirementSpecificationScopeRef
Operating modeConstantly in grid-forming modePCS§10.4.3
Operational scopeAll operating points, all SoC, production + demandPCS§10.4.3.1
Vector shift responseResist phase jump — supply P and Q instantaneouslyPCS§10.4.3.2 (1a)
Voltage amplitude responseSupply Q to reinforce voltage stiffnessPCS§10.4.3.2 (1b)
Response speedCurrent change within a few millisecondsPCS§10.4.3.2 (1c)
Current limiting coordinationMust not cause GFM discontinuityPCS§10.4.3.1 (f)
Island operationSeamless transition to island and backPCS§10.4.3.2 (2)
Oscillation dampingMust dampen: 0.2–1 Hz, 1–15 Hz, 15–45 HzPCS§10.4.3.2 (3)
Negative sequence currentMust supply to maintain voltage symmetryPCS§10.4.3.2 (4)
Coordination with PPCGFM fast response + PPC slower cascade to final valuePPC§13.2.2
No overdimensioning requiredGFM must not require oversizingPCS§10.4.3.1

Active power control and frequency control

23 requirements
RequirementSpecificationScopeRef
Active power setpoint accuracy± 3% of rated capacity (10s avg, ≤ 5 MW)PPC§11.3.5
Setpoint resolution≥ 0.1 MWPPC§11.3.3.1
Active power limitersBelow rated, both modes, 0.1 MW resolutionPPC§11.3.3.1
Rated capacity must not be exceededNot even momentarily — protective device if neededProtection§11.3.2.1
Over-capacity trip5% for 20s or 20% for 1sProtection§11.3.2.1
Ramp rate range0.1 × Pmax/min to 1.0 × Pmax/min (min 1 MW/min)PPC§11.3.3.2
Default ramp rate100% of rated capacity per minutePPC§11.3.3.2
Linear changeNo stepwise changes > 5%PPC§11.3.3.2
Separate up/down ramp setpointsMust be configurable separatelyPPC§11.3.3.2
Start-up voltage impactConnection must not cause > 3% voltage changeSystem§11.3.2.2
LFSM-O activation> 50.5 Hz, droop 2–12% (rec. 4%), delay ≤ 2sPPC§11.1.2
LFSM-O always enabledCannot be turned offPPC§11.1.2
LFSM-O overridesPrevails over all other active power setpointsPPC§11.1.2
LFSM-U activation< 49.5 Hz (demand mode: reduce demand), droop 2–12%PPC§11.3.3.4
LFSM-U always enabledCannot be turned offPPC§11.3.3.4
FSM droop2–12% in 1 pp steps, default 4%PPC§11.3.3.3
FSM deadband0.00–0.50 Hz in 0.01 Hz stepsPPC§11.3.3.3
FSM power range0–100% × Pmax, 0.1 MW steps, asymmetric possiblePPC§11.3.3.3
FSM per-range droopDifferent droop per frequency rangePPC§11.3.3.3
FSM on/off per rangeCan toggle frequency control per rangePPC§11.3.3.3
Frequency sensitivity≥ 10 mHzPPC§11.3.5
Frequency control start delay≤ 2 seconds on step changePPC§11.3.5
Mode transitionsNo sudden P or Q changesPPC§11.3.4

Reactive power capacity

10 requirements
RequirementSpecificationScopeRef
Q/Pmax,p ratio± 0.33 (cos φ = 0.95)System§12.2.1
Measurement pointConnection point (primary) or HV side of main trafoSystem§12.2.1
Voltage range for full Q0.90–1.05 puSystem§12.2.1
Applies across entire P rangeFull rated production and demand capacitiesSystem§12.2.1
Supplementary QMay be required if CP not at HV terminalsSystem§12.2.2
Separate compensation devicesAllowed — not limited to PCS onlySystem§12.2.3
Switchable capacitor banksNOT allowed for meeting Q requirementSystem§12.2.3
Q capacity calculationDeliver at Stage 1 to RNOSystem§12.2.4
Operating points for Q calc5 voltages (0.85–1.10 pu) × 4 power levelsSystem§12.2.4
Q must not be artificially limitedSoftware must not restrict; limiters documentedPPC§12.2.5

Voltage and reactive power control

18 requirements
RequirementSpecificationScopeRef
Three modes requiredConstant voltage, constant Q, constant PFPPC§13.2.1
Primary modeConstant voltage controlPPC§13.2.1
Voltage setpoint resolution≤ 0.1 kV stepsPPC§13.2.2
Voltage setpoint ramp≤ 0.1 kV/s average rate of changePPC§13.2.2
Voltage droop (slope)2–7% in ≤ 0.5 pp stepsPPC§13.2.2
Step response (0→80%)≤ 1 secondPPC§13.2.2
Overshoot limit≤ 15% of total Q changePPC§13.2.2
Settling time≤ 5 secondsPPC§13.2.2
Steady-state accuracy± 5% of target Q valuePPC§13.2.2
Cascade with GFMGFM fast initial → PPC guides to final valuePPC§13.2.2
Constant Q accuracy± 2% of rated Q (tol. ± 0.5%)PPC§13.2.3
Constant Q rise time10s (± 1s) for ± 30% rated Q stepPPC§13.2.3
Constant Q setpoint steps≤ 0.5% of rated Q (max 1 Mvar)PPC§13.2.3
Constant PF accuracy± 0.005 (tol. ± 0.002) at > 50% ratedPPC§13.2.4
Constant PF setpoint steps≤ 0.005 between 0.95ind and 0.95capPPC§13.2.4
No voltage deadbandType DType D: deadband not allowedPPC§13.3
POD (Power Oscillation Damping)Type DMay be required if oscillations affectedPPC§13.3
Fallback: central controller lostRO disconnects (partial or full)PPC§13.2.5

Remote control and SCADA interfaces

11 requirements
RequirementSpecificationScopeRef
Fingrid electronic control connectionOwner implements; SCADA interface to ROInterfaces§10.4.1.1
Response time — mode/setpoint changeImplemented within 1 minuteInterfaces§10.4.1.1
Reach new operating point (P, Q)≤ 15 minutes after Fingrid requestInterfaces§10.4.1.1
Control signals from Fingrid15 signals: P, Q, ramp rates, V/Q mode, droop, FSM, system stateInterfacesTable 10.1
Status signals to Fingrid6 signals: ack, status, SoC, P avail, Q avail, remote statusInterfacesTable 10.2
Direct control bus interfaceInput port for direct Fingrid control (per-project decision)Interfaces§10.4.1.2
RNO control commandsMay specify additional remote control and status signalsInterfaces§10.4.1.3
RO designationOwner must designate a Relevant OperatorInterfaces§10.4.1
RO availability24/7Interfaces§10.4.1.4
Continuous monitoringControllability and telecom connections — without delayInterfaces§10.4.1.4
Periodic testingRemote operation connections tested periodicallyInterfaces§10.4.1.4

Energy and state management

13 requirements
RequirementSpecificationScopeRef
SoC / energy availableReport to Fingrid (% or MWh)PPCTable 10.2
Active power capacity availableMW, separately for production and demandPPCTable 10.2
Reactive power capacity availableMvar, separately for inductive and capacitivePPCTable 10.2
Per-unit reportingIf capacity unevenly distributed across unitsPPC§11.3.2.1
Temperature dependenceReport how ambient temp affects capacityPPC§11.3.2.1
LFSM-U zero-transfer holdHold at P = 0 until f > 49.5 HzPPC§11.3.3.4
No disconnect during LFSM-ODown-regulation must not trip BESS or modulesPPC§11.1.2
Autonomous connection — frequency49.0–51.0 HzPPC§10.4.2
Autonomous connection — voltageWithin normal rangePPC§10.4.2
Autonomous connection — remoteRemote operation connection must be functioningPPC§10.4.2
Loss of control — individual unitContinue at last setpoints unless agreed otherwisePPC§10.4.1.4
Control not restored within 2 hoursMust be manned or disconnectedPPC§10.4.1.4
Recovery from network lossMust not cause factory resets or config lossPPC§10.2.6

Protection

10 requirements
RequirementSpecificationScopeRef
Priority ranking1. Network + equipment → 2. P/f control → 3. Power restriction → 4. GradientProtection§10.3.6
Settings responsibilityOwner specifies; coordinated with RNOProtection§10.2.5
Must not conflict with grid codeSettings shall not prevent FRT or other functionsProtection§10.3.6
RoCoF protection — Type C/DBANNED — must not use RoCoF relaysProtection§10.4.8
RoCoF protection — Type A/BAllowed only if threshold ≥ 4 Hz/s for ≥ 250 msProtection§10.2.5
Vector shift protectionOnly for < 50 kW; trigger ≥ 15°Protection§10.2.5
Recommended anti-islandingFrequency and voltage measurement basedProtection§10.2.5
Overvoltage limitersDirect and delay-free during high voltageProtection§13.2.6
Current limiter coordinationMaximise Q utilisation without trip riskProtection§12.2.5
Main transformer neutral earthingPer RNO specificationsProtection§10.4.6

Telecommunications and cybersecurity

4 requirements
RequirementSpecificationScopeRef
Cybersecurity responsibilityOwner responsible for all telecom and control systemsInterfaces§10.3.7
Unauthorized access preventionControl system + all remote access connectionsInterfaces§10.3.7
Supply chain cybersecurityExternal providers (equipment suppliers, RO) must complyInterfaces§10.3.7
InfoSec report to FingridReport on information security and telecom connectionsInterfaces§10.3.7

Black start and island operation

4 requirements
RequirementSpecificationScopeRef
Black start capabilityNotify RNO if BESS can be used for black startSystem§10.4.7
Island operation arrangementsAgree planned and disturbance island scenarios with RNOSystem§10.4.7
Unplanned island preventionBased on network status signals and protective devicesProtection§10.4.7
GFM intrinsic island capabilityGrid-forming converters inherently capablePCS§10.4.3.2 (2)

Power quality monitoring and instrumentation

6 requirements
RequirementSpecificationScopeRef
PQ assessment before connectionDeliver PQ impact reports to RNOPQM§10.4.5
Harmonic emission limitsPer Fingrid "Power quality in 110 kV grid"PQM§10.4.5
Type C instrumentationPer §9.3PQM§9.3
Type D instrumentationPer §9.4PQM§9.4
Commissioning test sampling≥ 1 kHz sampling, ≥ 50 Hz recordingPQM§15.3.1
Voltage control test sampling≥ 2 kHz at one converter modulePQM§15.3.1

Commissioning tests (Type C/D — 16 tests)

16 requirements
RequirementSpecificationScopeRef
1. LFSM-OFrequency steps/ramps ≥ 10% Pmax change, droop 4%, prod + demandPPC§15.3.4 (1)
2. LFSM-UFrequency steps/ramps ≥ 10% Pmax change, prod + demandPPC§15.3.4 (2)
3. Frequency sensitive mode (FSM)Full frequency range, ± 10% Pmax, droop/deadband per rangePPC§15.3.4 (3)
4. Rate of change of active powerAt 0.1 × Pmax/min and max rate, prod + demandPPC§15.3.4 (4)
5. Constant voltage controlStep response at slope 2% and 4%, internal + external voltage changesPPC§15.3.4 (5)
6. Constant reactive power controlStepwise Q changes, 0.3 × Qn steps, setpoint + ramp rate demoPPC§15.3.4 (6)
7. Constant power factor controlPF steps of 0.02, rise time demo, setpoint + ramp rate demoPPC§15.3.4 (7)
8. Reactive power capacity + P restriction4 operating points × max ind/cap, 15–30 min per pointSystem§15.3.4 (8)
9. Starting and stoppingNo quality deviations in RNO networkSystem§15.3.4 (9)
10. Voltage control disturbanceMode change on measurement loss — all planned modes verifiedPPC§15.3.4 (10)
11. Remote controlAll control locations, signal priority, automated fallback functionsInterfaces§15.3.4 (11)
12. Autonomous connection after network lossReturn to local control, no config reset, reconnect when authorisedPPC§15.3.4 (12)
13. Stable operation with PPMsStable alongside other grid-connected facilitiesPCS§15.3.4 (13)
14. Fault ride-throughPer §10.3.2 (Type C) or §10.5.3 (Type D) profilesPCS§15.3.4 (14)
15. Island modeSeamless transition and resynchronisationPCS§15.3.4 (15)
16. Angle jumpOperate under stepwise network voltage angle changePCS§15.3.4 (16)

Simulation models and dynamic studies

15 requirements
RequirementSpecificationScopeRef
Model formatsPSS®E and PSCAD™ (separately)System§16.1.1
Model scopeConverters, compensation, controllers, limiters, protectionSystem§16.1.1
Model aggregationSingle equivalent generator per sub-system of similar unitsSystem§16.1.2
Power flow simulationP-V dependence, voltage profiles, fault currentsSystem§16.1.3
PSS®E time resolution10 ms – 10 s (rapid change)System§16.1.4
PSCAD time resolution0.4 ms – 10 s (very rapid change)System§16.1.4
Model verificationCompare simulation vs commissioning test resultsSystem§16.1.5
DocumentationBlock diagrams (P/f, V/Q, other controls), parameters, instructionsSystem§16.1.5
Type D — stability impactType DElectromechanical oscillations and converter-based stabilitySystem§16.1.6
Type D — HIL testingType DFingrid may require Hardware-in-the-Loop verificationSystem§16.1.6
Dynamic study: voltage disturbancePSS®E + PSCAD at A4, A5System§14.1.1
Dynamic study: constant voltage controlPSS®E + PSCAD at A1–A5System§14.1.2
Dynamic study: network vector shiftPSCAD at A4, A5System§14.1.3
Dynamic study: island operationPSCAD at A4, A5System§14.1.4
Dynamic study: impedance scanPSCAD at A1–A5 (1–300 Hz)System§14.1.5

Compliance process timeline

StageTimingDeliverables
Stage 1Before connection agreementTechnical data, reactive power calculation, preliminary simulation models
Dynamic studies6 months before first power supplyStudy results + simulation models to RNO and Fingrid
Test plan2 months before commissioningTest plan, preliminary instructions, practical arrangements
Pre-test meeting2 months before commissioningAgree final test plan with RNO and Fingrid
CommissioningBefore commercial operation16 tests (Type C/D), 90% of converters operational
Model verificationAfter commissioningCompare simulation vs test results, deliver verification report
Requirements based on SJV2024 as published by Fingrid (15.1.2025, unofficial English translation).