louise jakobsen, danish energy association
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Automation in Distribution Networks (10 kV). Louise Jakobsen, Danish Energy Association. Agenda. Background Definition of automation Metodes of automation Prices for automation Conclusions. Background. Underground cables have replaced the 10 kV overhead lines in Denmark. - PowerPoint PPT PresentationTRANSCRIPT
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
Louise Jakobsen, Danish Energy Association
Automation in Distribution Networks (10 kV)
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
Agenda
Background
Definition of automation
Metodes of automation
Prices for automation
Conclusions
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
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.
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
Definition of automationThe 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!
2 3
1
2 3
1
2 3
Normal operation
Fault situation
Fault
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
Local or central automationAutomation 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
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
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
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
Short circuit indicator sees the fault
Circuit breaker open
No voltage,
no short circuit indicators
Circuit breakers open Voltage OK, switchgear close
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
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)
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
Reconfiguration based on load or grid lossesElectric cars and heat pumps may introduce new challenges to thenetwork 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 standardsshowing the electrical durabilityat switchgears or circuit breakerswhen many switching are carried out
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
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.
Losses in MWh Switching
Cables Transformers Total
Normal (feeder) 39,3 203 242
Meshed 35,3 203 238
Daily 37,6 203 240h
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
ConclusionAutomation 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 arenear or over the threshold valuein benchmarking automationmight pay off).
Benchmarking
(SAIFI
SA
IDI
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
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.
Louise Jakobsen, Danish Energy Association – Denmark – Session 3 – Paper 0811
Frankfurt (Germany), 6-9 June 2011
Thank you for your attention