REQUIREMENT

VALUE

REFERENCE STANDARD OR GUIDE

(including link)

PROTECTION REQUIREMENTS

Is an external accessible disconnecting switch mandatory?

YES

For operational and safety reasons all generators have to be equipped with a disconnection switch accessible to the grid operator.

The switch must at least be capable of disconnecting load current. If isolated operation of the installation is not predicted the switch dedicated to the de-coupling protection can be used as well. In any case the switch must guarantee the galvanic separation of the three phases and it must provide short circuit protection inside the installation

If isolated operation is predicted, the switch is placed at the limit of the islanded installations and it must be equipped with synchronization system for their parallel operation with the grid.

NA

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

+-10%

EN 50160

Is monitoring of voltage of each phase required?

YES (via GSM modem)

NA

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

5 secs

What is the acceptable range of frequency for operation of DER

+- 1%

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

10 secs

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

3 mins

Other protection requirements

NA

IMPACT ON GRID-POWER QUALITY

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

+- 3%

What is the limit of harmonic current emissions of DER

Individual Harmonic order. h- max distortion (%)

2: 2%

3: 5%

4: 1%

5: 6%

6: 0.5%

7: 5%

8: 0.5%

9: 1.5%

10: 0.5%

11: 3.5%

12: 0.2%

13: 3%

15: 0.3%

17: 2%

19: 1.5%

21: 0.2%

23: 1.5%

25: 1.5%

Even>12: 0.2%

Odd multiple of 3>21: 0.2%

Odd other than multiple of >25: 0.2+1.3* (25/h) %

THD: 8% at LV

IEC 61000-2-2, and IEC 61000-3-6

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

Frequency of switching operations, r

(h -1 : per hour, d -1 : per day)

For r > 1 h -1 :

Steady-state change, dc <=3 %

Maximum change, dmax <= 4 %

For 2 d -1 < r < 1 h -1 :

Steady-state change, dc <=3 %

Maximum change, dmax <= 5.5 %

For r < 2 d -1 :

Steady-state change, dc <=3 %

Maximum change, dmax <= 7 %

IEC 61000-4-15, IEC 61000-3-3, IEC 61000-3-5, IEC 61000-3-11, IEC 61000-3-7

Requirements regarding power factor

0.95 leading<Power Factor<0.95 lagging

Other requirements for impact on grid-power quality

PV SPECIFIC REQUIREMENTS

Is an AC disconnecting switch mandatory for a PV plant

NO

“Interconnection guide for photovoltaic stations to the LV network”, Public Power Corporation

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

-20% +15%

“Interconnection guide for photovoltaic stations to the LV network”, Public Power Corporation

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

<=0.5 secs

“Interconnection guide for photovoltaic stations to the LV network”, Public Power Corporation

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

+- 1%

“Interconnection guide for photovoltaic stations to the LV network”, Public Power Corporation

Is an isolation transformer required for a PV inverter

NO

“Interconnection guide for photovoltaic stations to the LV network”, Public Power Corporation

What is the maximum allowable DC current injected to the grid

In case of transformerless inverters incorporation, the DC component should not exceed 0.5% of the nominal value of the output current per phase of the inverter

“Interconnection guide for photovoltaic stations to the LV network”, Public Power Corporation

Is any special protection required for transformerless inverters

A RCMU (residual current monitoring unit) which has to be sensitive for DC currents). These DC fault current MUST NOT be mixed up with DC current injection! This unit is required only if VDE 0126 is not applied.

“Interconnection guide for photovoltaic stations to the LV network”, Public Power Corporation

Is an anti-islanding protection for the PV inverter mandatory

YES

“Interconnection guide for photovoltaic stations to the LV network”, Public Power Corporation

What method of anti-islanding protection is acceptable

Anti-islanding should be according to VDE 0126 or to an equivalent method which should be described.

“Interconnection guide for photovoltaic stations to the LV network”, Public Power Corporation