Post on 13-Feb-2018
transcript
Agenda
1) Introducing Network Planning and Constraints
• Limitations influencing Generation
• Security of Supply
2) Alternative Connections
• Timed
• Soft-Intertrip
• Active Network Management
3) Storage
Innovation in Grid Connection and Storage
Western Power Distribution DG Levels
• 7.8 Million Customers
• 55,000 sq km area
• 216,000 kms of linear assets
• 184,000 substations
• DG Capacity Connected up to Q3 2014 – MVA
• DG Connected March to September 2014 – MVA
• DG Capacity Offered and Accepted – MVA
Innovation in Grid Connection and Storage
4,100
640
8,800
What Influences Generation Connections?
Main technical barriers:
I. Power flow, thermal rating and losses
II. Voltage management (static and dynamic)
III. Fault level
IV. Power quality
V. Protection
VI. System issues for National Grid
Transient stability
exporting Grid Supply Points
balancing, etc.
VII. Security of Supply – ENA Engineering Recommendation P2/6
Innovation in Grid Connection and Storage
Curtailment for Standard Connections?
Generation connected under firm arrangements will have a resilient
supply, however the majority of DG is connected under non-firm
arrangements, so when the network is running abnormally, the
generation may need to be switched off.
Typically this occurs due to:
• Unplanned faults (transient, short-term and long term)
• Planned maintenance
• Planned new construction works
• Planned asset replacement
The duration of the abnormal running depends on the criticality of
the event and will range from milliseconds to months
Innovation in Grid Connection and Storage
TIMED
• Generation curtailed
within specific times
• Sub 1MVA
• Modelled seasonal capacity variations
• Localised control only
• No comms
• May have for voltage constraint
• Non-optimised
SOFT-INTERTRIP
• Releases pre-fault
capacity with trip
facility
• 11kV and 33kV
• Real-time monitored values
• Small clusters of generation or simple pinch points
• Existing monitoring with localised control
ACTIVE NETWORK MANAGEMENT
• Fully optimises capacity
based on all constraints
• Management of generation using LIFO principles
• Real-time granular control of output
• Requires new Active Network Management control and monitoring systems
Costs, Complexity & Network Optimisation
1010
1011
0100
Innovation in Grid Connection and Storage
Alternative Connections
Standard Connection Conventional connection (with CAF, where
applicable)
Traditionally all connection agreements have been in a single
format.
Alternative Connections can also be connected under three
additional commercial arrangements.
Enduring Alternative Connection Alternative connection (no CAF)
Interim Alternative Connection Alternative until reinforcement complete (CAF)
Part Standard, Part Alternative Increase capacity of existing standard
connection with additional Alternative capacity
top up
Innovation in Grid Connection and Storage
Alternative Connections
Trade-offs between Alternative Connections and
Conventional Reinforcement
Up Front Cost Ongoing Cost
Timed connections Low Curtailment (fixed by timed
restrictions, i.e. 11.3%)
Soft intertrip Medium Curtailment (depending on
et ork o ditio s, a d su -
opti al )
ANM Medium Curtailment (depending on
et ork o ditio s, opti al curtailment)
Capacity-based subscription fee
Conventional Reinforcement High / Medium / Low None
All o e tio s desig ed as o -fir ill e s it hed off for a or al ru i g
Innovation in Grid Connection and Storage
Estimating Curtailment
WPD uses historical
load data on its
network models and
superimposes
idealised generation
profiles to estimate
the level of
curtailment
experienced by the
connections
Innovation in Grid Connection and Storage
Solar Storage Description
• Techno-economic trial of a real battery energy storage system on
a large solar ge erator s side of the eter, i “o erset. • Quantify benefits for both the DNO and Customer with real data.
• WPD South West & 2 other project partners:
• What will be the benefits of generator connected storage?
• Generator earnings and project viability.
• Network management services.
• Explore routes to market – challenges and rewards.
• Making the case for energy storage in new connection offers.
Innovation in Grid Connection and Storage
Tech
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Inn
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De
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tpu
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25.Nov.13
09.Dez.13
23.Dez.13
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MVA
Business Challenges
• High demand for renewables connections in the South West.
• Renewable generation does not match peak local demand.
• ‘e e a le ge eratio has high ra p rates a d is ery `spikey . • Network capacity built for worst case scenarios and operated
within conservative limits.
• Power quality management is not currently provided by
renewables operators (other than specifying a power factor).
• No way of preventing race conditions without extra equipment.
Storage has been calculated to offer £60k/MVA/year of benefits to
distribution networks alone - how can these benefits be made
commercially realisable by DNOs?
Innovation in Grid Connection and Storage
Benefits split into 9 Usage cases
Innovation in Grid Connection and Storage
Usage Case. Beneficiary
1) Sell electricity for a higher price per kWh Owner
2) Shape generation profile to demand. DNO
3) Peak lop network demand (by exporting). DNO
4) Raise minimum demand to limit voltage rise. DNO
5) Voltage control. DNO
6) Peak lop generation to build bigger solar parks. Owner
7) Smoothing / Power Quality. DNO
8) Change peak lopping level (glass ceiling). DNO
9) Constructive system interactions DNO
DNO Limitations
• DNOs are required to maintain the network
• They are not allow to trade energy
• Battery vs conventional reinforcement
• When done for a connection we are obliged to offer the least
cost scheme
• Current governance limits the situations when we would be
able to use storage
Innovation in Grid Connection and Storage
Commercial Arrangements - economic upsides.
• On the customer side there are few limitations
• There is more access to other markets and revenue streams
• STOR
• Balancing (SSP spikes and demand customer SBP spikes)
• Triad payments (TNUoS)
• Significant reduction in connection costs if reinforcement
avoided.
• There is potential for commercial arrangements directly with the
DNO too (e.g. GDUoS)
• Real power network support (both import and export).
• Reactive power network support
Innovation in Grid Connection and Storage