1. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Louise Jakobsen, Danish Energy Association Automation in Distribution Networks (10 kV)

2. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Agenda Background Definition of automation Metodes of automation Prices for automation Conclusions

3. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Background Underground cables have replaced the 10 kV overhead lines in Denmark. Remote short circuits indicators and remote controlled switchgears are established in some secondary substations. In a report we have studied the feasibility to establish automation in secondary substations.

4. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Definition of automation The automation is for fault situations. The automation locates and isolates short circuit faults, before the primary station disconnects the faulty feeder. This means use of circuit breakers instead of switchgears!

5. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Local or central automation Automation can be established with local or central automation. Local automation:  The automation is isolated to selected secondary substations.  When a fault occurs the automated substations switches.  When an automatic switching has taken place, the control centre will be notified.  There is no communication between the automated secondary substations - they operate autonomously Control centre

6. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Local or central automation Central automation:  The automation has overview of all the secondary substations with communication.  The secondary substations report all observations to a control unit in the control centre (short circuits, earth faults, measurements, etc.).  The control unit decides how the operational situation has to be handled based on reports from the automated secondary substations. Central automation is far more advanced than local automation. Control Centre

7. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Short circuit indicator sees the fault Circuit breaker open No voltage, no short circuit indicators Circuit breakers open Voltage OK, switchgear close

8. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Prices Additional prices (2 functional units) Local automation contra remote switchgear: 900-3000 EUR Circuit breaker contra Switchgear: 2000 EUR (both motor operated from factory)

9. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Reconfiguration based on load or grid losses Electric cars and heat pumps may introduce new challenges to the network in terms of overload. This gives ideas to automated switching based on load or grid losses. But the investigation shows that: it is difficult to find two related feeders with max. load at different time there are no tests in the standards showing the electrical durability at switchgears or circuit breakers when many switching are carried out

10. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Grid losses Calculation of grid losses at ideal meshed 10 kV grid and grid with feeders shows that the biggest losses are in the transformers. The annual saving at daily switching after losses is 1,7 MWh. The conclusion is that the cost for automation to control the load and losses will be much higher than the benefits.

11. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Conclusion Automation in secondary substations is suited for: Feeders with branches Grids with many consumers Long feeders which in the case of a fault can be split up, so that half of the feeder can be reconnected quickly or get back-up supply. The quality of supply is high in Denmark (SAIFI 0,46) so the conclusion is:  that the cost for automation is too high! (but for network operators who are near or over the threshold value in benchmarking automation might pay off).

12. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Conclusion Automation is a new technical possibility. Society often embraces technology and expects that businesses and government use the technology. In time automation might be demanded by society:  in many secondary substations to improve quality of supply  at consumers with important functions like hospitals, police stations  at consumers with a great number of people gathering like stadiums, shopping centres and similar places  as a service to companies where long-term outages are expensive.

13. Frankfurt (Germany), 6-9 June 2011 Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811 Thank you for your attention