Smart Grids – do they fit into a real network? Laurie Curro, NPER, IEEE, B.Eng, MEng.Sc, Practice Leader Smart Grids
Agenda• Is our level of thinking on smart grids embedding crisis management?• Are we planning smart grids that can improve services to customers even at crisis times – or do we assume they won’t occur?• Are control rooms ready for this?• Case study – Self Healing networks• Are customers ready for smart grids?
Smart Grid - high level characteristics• Self-Healing and Adaptive• Interactive with consumers and markets• Optimized to make best use of resources and equipment• Predictive rather than reactive, to prevent emergencies• Distributed across geographical and organisational boundaries• Integrated, merging monitoring, control, protection, maintenance, EMS, DMS, marketing, and IT• More secure from attack
Typical smart grid components• Smart meters• Renewable energy sources• Home area networks• Communication infrastructure• Electric vehicles• Intelligent appliances• Grid side intelligent components In addition to an operating grid
Storm impact scenario• Vegetation clashing either through strong winds or water logging• Conductor clashing• Flying debris• Water ingress• Pole movement or fall Resulting• Other plant failure e.g. cross arms, cables, in switches, etc• Third parties e.g. car versus pole• In extreme conditions hail, ice • No power • Part power • Dim power • Intermittent power
Voltage Excursion scenario Severe Real voltage response at EP vs simulation using existing load model with load rejection transmission 1.1 1 fault 0.9 0.8 0.7voltage (pu) Simulated V 0.6 Real V 0.5 0.4 0.3 Resulting 0.2 0.1 0 in -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 time (s) Fault clearance in approx 100 to 250 m Considerable load rejection Temporary over voltage Tap chargers requiring up to one minute to re- adjust to a balance set point Unbalanced voltages
Frequency Excursion Scenario Sudden shutdown of Frequency one machine or50.2 more 5049.849.6 Resulting49.4 Fr…49.2 in 4948.848.6 0 50 100 150 200 250 Low frequency (47.5<f<50 Hz, for a 50 Hz system) for a period of a few cycles to many seconds Under frequency load shedding operated with up to 70% load lost depending on how low the frequency reached.
Impact on smart grid components Distributed energy May disconnect due to voltage instability storage May discharge unnecessarily Maybe damaged Electric Vehicles May disconnect due to voltage instability Fault locating equipment Should be operational Sectionalising switches Should be operational Condition monitoring Should be operational Self healing intelligence Maybe operational both centralised and Maybe inundated with data and not be capable of operating localised Distribution Maybe inundated with data and not be capable of operating management systems (local and centralised Backbone and last mile Maybe be swamped with data and essential communications communications Maybe inundated with un necessary data and not be capable of infrastructure operating or bottlenecked Firewalls, High levels/Excess traffic Home area networks Unknown level of reliability Energy management Unknown level of reliability services e.g. portals Load following May be lost Load monitoring Should be available but the data may not be reliable due to load rejection possibilities Intelligent appliances Unknown level of reliability
Data issues• Avalanche management• Priority of data• Latency of data• Separation of data• Back office systems• Customer data
A view from the control room• Distribution system control room• Designed and adapts to deal with large numbers of random events• How to manage the escalated level of information?• Data avalanches• Filter out critical parts• Priorities• Security of supply• Critical customers• SafetyUNLIKELY MUCH WILL CHANGE IN THE WAY THESE EVENTSWILL BE MANAGED IN NEAR FUTURE
A view from the customerPresent day important issues• Price of the service• Value for money• Reliability of service• Supply security
A view from the customerIs this a likely outcome?• Loss of Supply or grid connection (total or partial)• Some appliances may not be operating or struggling to do so• Information is lost or arriving with latency (IHD)• Internet portals may not be available• Utility not reachable (call avalanche)• Limited onsite energy storage• Unknown status of electric vehicle (is it charged or have the grid requirements discharged it)• Premise takes on a survival position
SELF HEALING - Defined Referring to a network or sub network that has the ability to sense, diagnose, isolate, and at least temporarily correct a fault or performance condition without human intervention.Feeder 1 OPEN OPEN CLOSE Feeder 2 OCB OCB RECLOSE fault Autopilot!Feeder 4 Feeder 3 OCB OCB
SELF HEALING – 3 critical elements Communications Power networks world world •Status information•Built In diagnostics e.g. TDR•Diagnostics are on line Discovery •Line fault indication •Additional comms/SCADA•Diversity in layers •Alternative feeders•Already feeding data•Independent of physical layer Alternative routing •Capacity is available•Smart routing •Switching capability•Drivers could be different•Capacity may not be an issue Switching Capability •Break before make •Some loss of supply•No loss of service
Why do you need to be careful? This is business as usual
SELF HEALING – risks involved •Incomplete status information •Reliability if overhead line fault Discovery indicators •Unknown unknowns •Load growth – load peaks Alternative routing •Alternative feeders •Capacity is available •Switching capability •Cold load pick upSwitching Capability •Switching transients •Secondary faults?
Benefits• Reliability • Restoration (or CAIDI) benefit of customers • Doesnt avoid the faultOther benefits• Move load to avoid unexpected peaks• Manage voltage issues• Increase security in some areas for short periods of time• Can you use self healing to ignore maintenance?
Costs / Issues• Planning criteria• Cost of redundancy• Cost of alternative paths• Business process issues & changes• Expectation management• Risk benefit – trade off• Operational Safety implications • LV & HV open points • System can become alive!!
SP-AusNet Experience• Configuration management is paramount• Automate the associated work processes wherever possible• Need to be able to rely on your network data• Implementing these schemes requires a collaborative organisational effort (typically involves multiple Divisions/Departments etc.)• Need to win the hearts and minds of the network controllers in order to be successful (and this takes time and effort)• If you have built the applications outside of an integrated technology platform arena you need to have a long-term plan in place to ultimately transition it into a formal DMS/OMS environment.
Western Power Experience• Concentrated on Hazard & risk Identification• Software trial- listening mode approach on DMS• Flow Chart of Automated Feeder restoration• Established Principles of operation • Maximum number of customers restored • Minimum switching required • Critical customer restoration• Established Rules• Operational Requirements • Time delay issues - communications specific • Minimise the dead time <2minutes • Work practice issues
Western Power ExperienceOther Issues for Consideration• Protection reach• Voltage constraints• Conflicting schemes• Under Frequency load shedding (UFLS)• Under-voltage load shedding (UVLS)• Sensitive earth fault protection• Other solutions maybe better eg edge of grid locations
Conclusions• It is likely that the performance and impact of severe events has not been covered in most smart grid strategy or implementations planning• It is important that a glide path for smart grid technology recognises the practicalities of existing networks• Issues such as security of supply to customers need to be considered - In the case of the phone revolution this was not seen as critical as in that case extra services were provided.• Most of the efforts to date seem to concentrate on benefits realisation or technology development• The deployment of smart grid should adopt an initial mantra of “keeping it simple” in order to realise benefits• It is unlikely that customers are ready – customer behaviour changes are needed• Gradual, considered and phased and considered approach is recommended - It may take a generation to turn customers around.
Thank you for listening. Questions Please(SKM acknowledges the contributions of SPAusNet and Western Power to this presentation)
ContactFor more informationLaurie Currolcurro@globalskm.com+61 8 9469 4397Visit www.globalskm.com