1. Frankfurt (Germany), 6-9 June 2011 Irina Melnik – the Netherlands – Session S2 – 0665 Intelligent Distribution Substation improves power quality

2. Frankfurt (Germany), 6-9 June 2011 Need for new technologies  Monitoring and control  New technologies  Changes in power flows  Larger voltage variations  Uncertainty for planning  Complex grid operation  Fluctuating loads  Distributed generation MV LV Load Power MV LV Load Power

3. Frankfurt (Germany), 6-9 June 2011 Intelligent distribution substation (IntDS) Additional functions of the IntDS:  Monitoring  Control  Improving Power Quality  Developed by a consortium of Dutch industries  Installed and tested in the grid of DSO Alliander

4. Frankfurt (Germany), 6-9 June 2011 “Intelligent” components of IntDS Electricity storage system with bidirectional inverter Measurement system Smart Transformer

5. Frankfurt (Germany), 6-9 June 2011 IntDS implementation District with large amount of micro Combined Heat Power at customers

6. Frankfurt (Germany), 6-9 June 2011 Test program  Voltage control  Reduction of harmonic distortion  Reduction of flicker  Mitigation of voltage dips Power Quality improvement by the IntDS:

7. Frankfurt (Germany), 6-9 June 2011 Voltage control Performed by Smart Transformer:  Electronic tap changer ensures a constant voltage level on the LV rail of the IntDS.  The voltage control set-point has to be determined to achieve the optimal voltage level on PCC’s of all LV customers. Smart Transformer

8. Frankfurt (Germany), 6-9 June 2011 Voltage control – test results U avg U max U min LV bus-bar 1 2 3 control no control LV customer 1 2 3 control no control

9. Frankfurt (Germany), 6-9 June 2011 Harmonic distortion reduction Performed by ESI (Electricity storage inverter) :  Resistive harmonic damping  Passive harmonic damping The filter capacitors of the ESI take part in the filtering of harmonics. Electricity storage system with bidirectional inverter

10. Frankfurt (Germany), 6-9 June 2011 Harmonic distortion reduction – test results H03 max H05 max H07 max THD max LV bus-bar control no no control LV customer controlno control no

11. Frankfurt (Germany), 6-9 June 2011 Voltage dips mitigation  Can be performed by: the Smart Transformer the ESI (Electricity storage inverter)  Voltage dips occur only a few times per year on an LV bus-bar of Dutch distribution substations. That’s why this functionality is not actively tested.

12. Frankfurt (Germany), 6-9 June 2011 Flicker reduction (LV side) Performed by:  The electronic tap changer of the Smart Transformer  The flicker reduction control of the bidirectional inverter (ESI) of the storage system.

13. Frankfurt (Germany), 6-9 June 2011 Flicker reduction – test results Plt avg Pst avg Plt max Pst max LV bus-bar no control LV customer no control

14. Frankfurt (Germany), 6-9 June 2011 Conclusions  The Intelligent substation has proved to be safe in operation.  The first field test results demonstrate a significant reduction of voltage variations, harmonic and THD levels both at the LV bus-bar of the IntDS and at the LV customers.  Further metering and test programs will be performed to set optimal set-points for control equipments.  The proved principles can be used for area’s with high levels of PQ distortions. Irina Melnik – the Netherlands – Session S2 – 0665