WIND INTEGRATION USE CASE

How to increase connection capacity, infeed, and reduce curtailment

2019

Problem statement

Hosting capacity of wind power may be limited by:

• Thermal capacity limit of power line:

• Connecting the wind farm to the grid

• Transporting wind energy through the grid

• Voltage limits

• Stability limits

• Protection settings

This causes:

• Limit to size of installation

• Limit to amount of infeed

• Delay in getting connected and operating in full

How does DLR benefit wind integration?

Hosting capacity of wind power may be limited by:

• Thermal capacity limit of power line:

• Connecting the wind farm to the grid

• Transporting wind energy through the grid

• Voltage limits

• Stability limits

• Protection settings

DLR is well-suited to ease integration of wind power when thermal capacity is the limit

Safe increase of power line capacity to transfer higher amounts of current

• Increase connection capacity without increasing line capacity

• Reduce curtailment

• Faster connection as in between measure until reconductoring in place

Typical wind power connection to grid

A. Connection to grid is limited by N-1 limit of grid, calculated based on capacity limits of power lines and substationse.g. in N-1, the outage of the red line is considered.

the amount of wind power that could be delivered is limited to the carrying capacity of the remaining line

B. Connected wind farm capacity is limited by the capacity limit of the connection to grid

Wind farm

Traditional to progressive approach to wind connection

Traditional approach

• Hosting capacity based on static limits

• No permission to connect any installation capacity exceeding the static limit

• Permission is granted after grid capacity is increased by reinforcement

Connected wind capacity exceeds

hosting capacity but infeed is based on

static limits

• Permission is granted on basis that infeed will be curtailed when it results in an N-1 security violation

• Analogous to German “Spitzungkappung”, Belgian “GenFlex”, Japanese “Connect&Manage” concepts

Connected wind capacity exceeds

hosting capacity but infeed is based on

dynamic limits

• Wind infeed correlates with increased line capacity

• N-1 security limit increases when dynamic line rating provides gain

• Reduces curtailment compared to previous case

AMPACIMON CASE STUDY

based on 5 years of sensor data

Offshore wind developments in Belgium

• In the North Sea, large-scale offshore wind farm projects have been developed.

• Connections to Belgium have grown since 2009 from 200MW to 1200MW in 2018.

• Future growth expected to be over 2GW.

Data sources:https://www.reboostende.be/offshore-wind-farmshttps://rentel.be/en/about-rentelhttp://www.nobelwind.eu/#description

Data available on Offshore wind in Belgium

Elia publishes installed capacity and infeed on 15-minutely basis from 2014

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[MW

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Offshore wind infeed to Elia Grid 2014-2018

Data source: Elia http://www.elia.be/en/grid-data/power-generation/wind-power

15-minutely wind infeed

Installed capacity

Onshore connection points

➢ Belgian offshore wind installations concentrated in one location.

➢ Onshore connections to Slijkens/Oostende and Zeebrugge/Stevin substations.

➢ “Stevin” 380 kV link project began in November 2017 to alleviate the sub-transmission network

➢ Until then, only 150kV network existed

https://www.elia.be/en/about-elia/publications/maps

Red line: 380kV, Black line: 150kV

Monitoring of 150kV sub-transmission lines carrying wind power infeed

• Offshore wind feed in to Slijkensand Zeebrugge substations

• High loading on 150KV lines Slijkens – Brugge - Langerbruggeconnecting the offshore wind

• DLR sensors installed to monitor high loads since:

• Slijkens-Brugge 2010

• Brugge-Langerbrugge 2014

Line ratings based on actual historical data

150kV double circuit line in coastal area connecting wind infeed

Sample shown: Static and dynamic rating from 2014-2018

Dynamic Line RatingStatic Line Rating

Line rating for single circuit

Ampacity gain from 5 years of observation

• Maximum gain over 200%• DLR gain was available 98% of the time

127-130% on average90% of the time 110-116%95% of the time 105-115%2% of the time nominal rating is risky

Nominal rating

Our sensor rating

Results from case study are in agreementwith other studies• With increasing installation capacity considered on same line,

curtailment begins when the installation capacity exceeds the thermal limit of the line.

• For this 150KV line, if SLR is considered curtailment begins at 150MW, while if DLR is considered it begins at 230MW

• In general, curtailment increases but so does infeed. (Also supported by external Italian case study)

• DLR can reduce curtailment by up to 15% compared to SLR. (Also supported by external Swedish case study and Italian case study)

• No curtailment results even if installation capacity exceeds SLR of the connection. Up to 50% increase in installation capacity does not result in any curtailment! (Also supported by external UK case study)

THIRD-PARTY REFERENCESAre the results in line with other studies?

Case for UK Central Networks: DLR can increase 20-50% wind connectionDLR evaluated on two double-circuit lines:

• 132kV between Skegness - Boston (North East of England)

• 110kV between Omagh – Dungannon (Northern Ireland Electricity)

Comparison of seasonal ratings (P27) with DLR using various methods

2008

4-papers describing the same project were published in 2009-2010 by UK Central Networks with ArevaT&D/Alstom/GE).

• T. Yip, C. AN, G. Lloyd, M. Aten, B. Ferris, Dynamic line rating protection for wind farm connections, Integration of Wide-Scale Renewable Resources Into the Power Delivery System, 2009 CIGRE/IEEE PES Joint Symposium. p.p. 1-5. 29-31 July. Calgary – Canadian. 2009.

• T Yip, C An, G Lloyd, M Aten, B Ferris, G. Hagan, Field Experiences With Dynamic Line Rating Protection, Developments in Power System Protection 2010.

• T. Yip, M. Aten,. B. Ferris, GJ. Lloyd, AN. Chang , Dynamic line rating protection for wind farm connections, 20th International Conference and Exhibition on Electricity Distribution - Part 1, CIRED 2009.

• M. Aten, R. Ferris, Dynamic line rating protection for wind farms overview of project, IET Conference on Substation Technology 2009: Analysing the Strategic and Practical Issues of Modern Substation, 2009.

Case for Italy TERNA: DLR can increase wind infeed

DLR was evaluated on line:

• 150 kV Line Benevento2 –Foiano for increasing wind infeed

Wind installation increased from 535MW to 666MW between 2010 to 2013 (figure top right)

No grid reinforcement, only DLR!

Wind infeed (figure top right) and grid capacity (figure bottom right) could be increased from 2010 to 2013

2012/3

Reference: E. M. Carlini, F. Massaro, C. Quaciari, Methodologies to uprate an overhead line. Italian TSO case study, J. Electrical Systems 9-4 (2013): 422-439 https://journal.esrgroups.org/jes/papers/9_4_4.pdf

Case for Italy TERNA: DLR can reduce wind energy curtailment

DLR was evaluated on line in 2012:

• 220 kV Line Misterbianco - Melilli in Sicilian electrical grid in order to increase N-1 security

Wind energy is usually curtailed due to various reasons (figure top right) with DLR, significant reduction in curtailment was observed.

Wind infeed increased from 2011 to 2012, and correspondingly the curtailment also reduced from 6 to 1% between 2010 and 2012 (figures bottom right)

2012/3

Reference: E. M. Carlini, F. Massaro, C. Quaciari, Methodologies to uprate an overhead line. Italian TSO case study, J. Electrical Systems 9-4 (2013): 422-439 https://journal.esrgroups.org/jes/papers/9_4_4.pdf

Case for Swedish DSO: DLR can reduce 15% of wind energy curtailment

Swedish DSO study evaluated how many 3-MW wind turbines could be connected to its grid.

5 alternatives were compared:

1. Existing connection using Static Line Rating (SLR1)

2. Reinforcing the connection but still applying Static Line Rating (SLR2)

3. Existing connection using Dynamic Line Rating considering only ambient temperature impacts (DLR1)

4. Existing connection using Dynamic Line Rating considering only wind impacts (DLR2)

5. Existing connection using Dynamic Line Rating considering both wind and ambient temperature impacts (DLR3)

Results

• Curtailed wind energy due to these limitations increases with the number of connected turbines.

• SLR1 leads to the highest curtailment.

• SLR2 (classical reinforcement) leads to least curtailment

• DLR3 has lowest curtailment amongst all DLR methods.

Reference: Carl Johan Wallnerström, Yalin Huang, Lennart Söder, Impact From Dynamic Line Rating on Wind Power Integration, IEEE TRANSACTIONS ON SMART GRID, VOL. 6, NO. 1, 343-350, JANUARY 2015

https://www.diva-portal.org/smash/get/diva2:739564/FULLTEXT01.pdf

Number of 3-MW wind turbinesCu

rtai

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win

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gy [

%]

2014