1. Frankfurt (Germany), 6-9 June 2011 Minimum short circuit power in the LV distribution network to meet EN 50160 standard requirements David MEZERA david.mezera@eon.cz Martin KAŠPÍREK martin.kaspirek@eon.cz E.ON Czech Republic – Czech Republic

2. Frankfurt (Germany), 6-9 June 2011 This investigation was done on the basis of:  8 years experience of PQ measurement  Evaluated over 3000 measurements PQ in the LV network  The LV network contains of 18.005 MV/LV distribution substation [piece] 21.660 LV cable underground line [km] 17.151 LV overhead line [km]  Real LV network was monitored for a long time on 3.000 different PCC The sources of this survey

3. Frankfurt (Germany), 6-9 June 2011 The final result of 3.000 measurements PQ

4. Frankfurt (Germany), 6-9 June 2011 Who is responsible?  DNO Pure network=low short circuit power (Sk)? Badly connected customers?  Customers Using of nonstandard apparatus? Electric apparatus?

5. Frankfurt (Germany), 6-9 June 2011 Minimum short circuit power LV  Thanks to IEC 725 we can set the reference impedance value, or more precisely, a relative short circuit power value for the LV distribution network and electric equipment of nominal current less than 16/75 A Electric equipment with nominal current Reference short circuit impedance [Ω] Reference short circuit power [kVA] up to 16A0,28570 up to 75A0,21760

6. Frankfurt (Germany), 6-9 June 2011 Relation: short circuit power X PQ

7. Frankfurt (Germany), 6-9 June 2011 Relation: short circuit power X PQ

8. Frankfurt (Germany), 6-9 June 2011 Relation: short circuit power X PQ

9. Frankfurt (Germany), 6-9 June 2011 Relation: short circuit power X PQ

10. Frankfurt (Germany), 6-9 June 2011 Conclusions for DNO  To connect the new appliances according to Sk in the LV network  To increase Sk above minimum Sk 760 kVA, (900 kVA is recommended for today real used electric appliances) To increase the cross-section of existing LV overhead lines To build new MV/LV substations

11. Frankfurt (Germany), 6-9 June 2011 To increase the cross-section of the existing LV overhead lines  To increase the cross-section of the existing LV overhead lines not realizable

12. Frankfurt (Germany), 6-9 June 2011 To build new MV/LV substations The final calculation is:  54% new substations. This accounts for a construction of 9723 new substations, including transformers and MV connection with approximate total investment cost of: EUR 280 million.

13. Frankfurt (Germany), 6-9 June 2011 Conclusion  The pure PQ in LV network is caused by poor conditions on both sides, DNO and customer. Solution on the side of DNO is calculated on 280 million EUR. Solution on the side of customers ??