smart grid - do they fit into real networks ver 1
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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 overview
Diagram
Courtesy
EPRI
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
• Other plant failure e.g. cross arms, cables,
switches, etc
• Third parties e.g. car versus pole
• In extreme conditions hail, ice
• No power
• Part power
• Dim power
• Intermittent power
Resulting
in
Voltage Excursion scenario
Real voltage response at EP vs simulation using existing load model
with load rejection
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
-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)
vo
lta
ge
(p
u)
Simulated V
Real V
Severe
transmission
fault
Resulting
in
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
48.6
48.8
49
49.2
49.4
49.6
49.8
50
50.2
0 50 100 150 200 250
Frequency
Fr…
Sudden shutdown of
one machine or more
Resulting
in
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
storage
May disconnect due to voltage instability
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
both centralised and
localised
Maybe operational
Maybe inundated with data and not be capable of operating
Distribution
management systems
(local and centralised
Maybe inundated with data and not be capable of operating
Backbone and last mile
communications
infrastructure
Maybe be swamped with data and essential communications
Maybe inundated with un necessary data and not be capable of
operating or bottlenecked
Firewalls, High levels/Excess traffic
Home area networks Unknown level of reliability
Energy management
services e.g. portals
Unknown level of reliability
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
• 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
• Safety
UNLIKELY MUCH WILL CHANGE IN THE WAY THESE EVENTS
WILL BE MANAGED IN NEAR FUTURE
A view from the control room
A view from the customer
Present day important issues • Price of the service
• Value for money
• Reliability of service
• Supply security
A view from the customer
Is 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
Case study
Self healing networks
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
OCB
Feeder 2
OCB
Feeder 3
OCB
Feeder 4
OCB
fault
OPEN OPEN CLOSE
RECLOSE
Autopilot!
Switching Capability
•Built In diagnostics e.g. TDR
•Diagnostics are on line
•Diversity in layers
•Already feeding data
•Independent of physical layer
•Smart routing
•Drivers could be different
•Capacity may not be an issue
•No loss of service
•Status information
•Line fault indication
•Additional comms/SCADA
•Alternative feeders
•Capacity is available
•Switching capability
•Break before make
•Some loss of supply
Discovery
Alternative routing
Communications
world
Power networks
world
SELF HEALING – 3 critical elements
Why do you need to be careful?
This is business as usual
Text only slide
Switching Capability
•Load growth – load peaks
•Alternative feeders
•Capacity is available
•Switching capability
•Cold load pick up
•Switching transients
•Secondary faults?
Discovery
Alternative routing
SELF HEALING – risks involved
•Incomplete status information
•Reliability if overhead line fault
indicators
•Unknown unknowns
Benefits
• Reliability
• Restoration (or CAIDI) benefit of customers
• Doesn't avoid the fault
Other 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 Experience
Other 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)
