REQUIREMENT

VALUE

REFERENCE STANDARD OR GUIDE

(including link)

PROTECTION REQUIREMENTS

Is an external accessible disconnecting switch mandatory?

•  For plants with a performance less or equal 30 kVA is a facility for the monitoring of the grid with a particularly assigned switch in sequence necessary (ENS)

•  > 30 kVA: external accessible disconnecting switch mandatory

•  DIN VDE 0100-551 (VDE 0100-551)

•  DIN VDE 0100-537 (VDE 0100-537)

•  DIN VDE 0126 (VDE 0126 )

•  Directives of the Association of the Energy and Water Industry

What is the acceptable range of AC voltage for operation of DER?

+/-10 % for Un = 230 V or 400 V

Undervoltage: 0,7 - 1,0 of rated voltage

Overvoltage: 1,0 - 1,15 of rated voltage

•  DIN EN 50160 (April 2008)

•  DIN IEC 60038 (Standard Voltages)

•  DIN VDE 0100-551

•  IEC 60364-5-51

Is monitoring of voltage of each phase required?

No

What is the maximum allowed time for disconnection of DER in case of a voltage out of range event

•  Voltage dip: 10 to 100 per year (10 ms up to 1 s, 1% up to 90% U n )

•  Short disconnection: 10 to 100 per year, 70% < 1 s (Duration: < 3 min)

•  Long disconnection: 10 to 50 per year (duration: > 3 min)

What is the acceptable range of frequency for operation of DER

Underfrequency: 47 - 50 Hz

Overfrequency: 50 - 52 Hz

•  DIN EN 50160 (April 2008)

•  DIN VDE 0100-551

•  IEC 60364-5-51

What is the maximum allowed time for disconnection of DER in a case of a frequency out of range event

What is the minimum time for reconnection after a disconnection of DER

Other protection requirements

IMPACT ON GRID-POWER QUALITY

What is the allowable variation of voltage at LV side of LV/MV transformer, due to DER connection

+- 10%

DIN EN 50160 (April 2008)

What is the limit of harmonic current emissions of DER

According to regulations

•  EN 61000-3-2

•  EN 61000-3-12

What is the limit of the voltage fluctuations and flicker for DER

•  LV : According to regulations

•  MV: A lt : 0,1

P lt : 0,46

•  EN 61000-3-2

•  EN 61000-3-12

Requirements regarding power factor

•  No compensation for DER up to 4.6 kVA in LV grids: 0.9 leading to 0.8 lagging is tolerated

Other requirements for impact on grid-power quality

PV SPECIFIC REQUIREMENTS

Is an AC disconnecting switch mandatory for a PV plant

YES

DIN VDE 0126 (VDE 0126 )

What is the acceptable range for the settings of under-voltage disconnection

What is the maximum allowed time for disconnection of a PV inverter in case of a voltage out of range event

What is the acceptable range of settings for under- over frequency disconnection

What is the maximum allowed time for disconnection of a PV inverter in case of a frequency out of range event

200 ms

DIN VDE 0126 (VDE 0126 )

What is the minimum time for reconnection after a disconnection of a PV inverter

What is the limit of the total harmonic distortion of current of a PV inverter

Is an isolation transformer required for a PV inverter

What is the maximum allowable DC current injected to the grid

Is any special protection required for transformerless inverters

Is an anti-islanding protection for the PV inverter mandatory

What method of anti-islanding protection is acceptable