1 Results of the GTZ/DEA&DP Grid Study for the Western - - PDF document

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1 Results of the GTZ/DEA&DP Grid Study for the Western - - PDF document

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International Studies about the Grid Integration of Wind Generation Dr.-Ing. Markus Pller/DIgSILENT GmbH PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011 Internation Studies About

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PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

International Studies about the Grid Integration of Wind Generation

Dr.-Ing. Markus Pöller/DIgSILENT GmbH

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Internation Studies About Grid Integration of Wind Generation

  • Grid Integration of Wind Generationin South Africa:

– The GIZ/DEA&DP Grid Study for the Western Cape/South Africa – GIZ/DOE/ESkOM: Capacity Credit of Wind Generation in South Africa

  • “DENA-II-Study”

Integration of Renewable Energies into the German electricity transmission system during the time frame 2015-2020 with an outlook until 2025

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Results of the GTZ/DEA&DP Grid Study for the Western Cape/South Africa

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011 PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Situation in South Africa

  • Since 2009: Feed-in tariff scheme is in place (1,25ZAR/kWh around

0,14USD/kWh)

  • Only a few test turbines in operation (end of 2009)
  • Wind farm developments in the Cape (Western and Eastern Cape) started.
  • High uncertainty about the overall amount of wind generation that will get a

permission to connect to the grid.

  • The grid study (2009) represents an initial feasibility study looking at the high

voltage transmission system.

  • The capacity credit study (2010) looks at the contribution of wind generation to

the equivalent firm capacity and system operational aspects.

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PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

The South African Transmission System Western Cape

Stage 3 Stage 2 Stage 1

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

The GTZ/DEA&DP Grid Study - Approaches

  • Consideration of all wind farms in the Western Cape, for which

application existed by end of March 2009 (2798MW)

  • High level feasibility studies considering the existing ESKOM

transmission grid (excluding subtransmission, <=132kV)

  • Constraints:

– No major network upgrades (such as new lines) – Minor network upgrades, such as additional var-compensation is possible.

  • System 2009 (not considering network extensions that are planned for

the next 10 years.)

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PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

The GTZ/DEA&DP Grid Study - Approaches

  • Required grid reinforcement at subtransmission levels (132kV) out of

the scope of this study

  • Lumping all wind farms in a specific region together and modelling

them as an equivalent infeed into the nearest 400kV substation

  • Aurora

Ankerlig Power Station Muldersvlei Koeberg Power Station Juno L1-WFD L1-WFA L1-WFJ

Muldersvlei 132 CX3

G ~

Koeberg Gen1

G ~

Koeberg Gen2 Juno 400 RX2 Juno 400 RX1 Aurora 400 RX1 Aggeneis 220 RX1 Aggeneis 220 RX2 Aurora 132 CX2 Aurora 132 CX1

G ~

Ankerlig Gen 43

G ~

Ankerlig Gen 42

G ~

Ankerlig Gen 41

G ~

Ankerlig Gen 32

G ~

Ankerlig Gen 31

G ~

Ankerlig Gen 11 Muldersvlei SVC SCX Muldersvlei SVC F

SVS

Muldersvlei SVC Gromis 66 Load TX Aurora 132 Load TX Aggeneis 66 Load TX

  • eberg-Stikland 400_1 S1

Koeberg-Muldersvlei 400_2 S3(1) Koeberg-Muldersvlei 400_2 S3 Koeberg-Muldersvlei 400_2 S2( Koeberg-Muldersvlei 400_2 S1 Helios-Juno 400_1 S2 Helios-Ju vlei 400_1 S1 Aurora-Juno 400_1

G ~

Ankerlig Gen 12

G ~

Ankerlig Gen 21

G ~

Ankerlig Gen 22

Ankerlig-Koeberg 400_2 Ankerlig-Koeberg 400_1 Ankerlig-Aurora 400_2 Ankerlig-Aurora 400_1 Acacia-Muldersvlei 400_1 S2 acia-Koeberg 400_1 S1

Muldersvlei 132 CX1 Muldersvlei 132 CX2 Nama 66 Load TX Muldesrvlei 132 Load TX Muldersvlei 66 Load TX

.. ..

Koeberg 132 Load TX Juno 66 Load TX

Aurora Juno Darling

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

The GTZ/DEA&DP Grid Study - Approaches

  • Definition of credible worst-case scenarios:
  • Analysed cases:

– High load, 1 Koeberg (nuclear power plant) units in – High load, 2 Koeberg units in – Low load, 1 Koeberg unit in – Low load, 2 Koeberg units in

  • Generation Balancing – High Wind Scenarios:

– Reduction of Gas Turbine Generators (running in SCO mode where possible) – Reduction of pump storage generation at Palmiet – Reduction of coal power plants outside the Cape

  • Load flow and contingency analysis studies looking at thermal and voltage

aspects only.

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PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

2800MW in the Western Cape – Summary of Results

  • Up to 1000MW of export from the Cape to the North under Low load – High

Wind conditions (without wind, the Cape system has rather an import problem).

  • No violation of thermal limits under n-1 conditions in all scenarios.
  • Voltages can be maintained within appropriate limits, without any additional

reactive power compensation in the Western Cape.

  • The general feasibility of the integration of up to 2800MW of wind generation

in the Western Cape, with regard to the impact on the transmission grid, could be demonstrated.

  • However:

– Operation of the system with considerable export from the Cape to the North must be studied in further detail. – More detailed studies are required for confirming these results.

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Integration of Wind Energy into the Western Cape System - Summary

Western Cape transmission system – excellent for wind integration:

  • Cape system currently has an import problem (no export problem).

Power import will be reduced during times of high wind generation.

  • Large number of fast acting peak load units available that can be used

for balancing wind variations.

  • Pump storage can be used for supporting the balancing of wind

variations.

  • Some GTGs allow for SCO-operation – no need for additional dynamic

reactive power compensation (SVC). At subtransmission levels (<=132kV), transmission capacity will be limited in some cases.

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PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

What else needs to be done

  • Additional, more detailed studies at transmission levels, including

additional generation-load scenarios and alternative wind generation scenarios.

  • Stability studies under various operating scenarios.
  • Wind farm connection studies for every wind farm application.
  • Studies related to transmission system operation under situations, in

which the Cape exports power to the rest of the system

  • Studies related to the expected total power variations of wind

generation (variations, ramp-up and ramp-down speeds) for identifying additional reserve requirements have to be carried out.

Capacity Credit of Wind Generation in South Africa

Markus Pöller/DIgSILENT GmbH

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

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Capacity Credit Studies for South Africa

  • Studies commissioned by:

Studies commissioned by:

  • Studies executed by:
  • With contributions from:

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

  • South African system

– 2015: installed capacity: 52537MW, peak demand: 40582 MW – 2020: installed capacity: 59753MW, peak demand: 48315MW

  • Part1: Assessment of capacity credit of wind generation in South

Africa for the following scenarios

– Sc1: 2015: 2000MW of wind generation – Sc2: 2020- low wind: 4800 MW of wind generation – Sc3: 2020- high wind: 10000MW of wind generation

  • Part2: Impact on residual load variations

Scope of Work

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

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Methodology - Summary

  • Capacity Credit calculated based on LOLP at daily peak loads.
  • Evaluation of Capacity Credit is based on the increase of available

reserve at given confidence level.

  • Dispatchable units modelled by 2-state Marcov models and

deterministic maintenance plan

  • Load modelled by daily peak loads
  • Wind generators modelled by wind speed time series and generic

power curve.

  • Approach considers:

– Correlation of wind speeds with seasonal load variations. – Correlation of wind speeds with daily load variations. – Correlation between wind speeds at different sites. – Correlation of planned outages with load (maintenance schedule).

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

  • Installed Conventional Capacity:

52 537MW

  • Yearly Peak Demand:

40 582MW

  • Equivalent Firm Capacity:

535 MW

  • Capacity Credit:

26,8%

  • Corrected CC:

30,0 %

  • Average capacity factor of wind generation:

27,2%

  • Average capacity factor during full load hours:

30,0%

  • Capacity reduction factor CR:

0,89 Study Results – SC1 - 2015

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

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  • Installed Conventional Capacity:

59 743MW

  • Yearly Peak Demand:

48 315MW

  • Equivalent Firm Capacity:

1218 MW

  • Capacity Credit:

25,4%

  • Corrected CC:

28,2 %

  • Average capacity factor of wind generation:

30,6%

  • Average capacity factor during full load hours:

34,4%

  • Capacity reduction factor CR:

0,74 Study Results – SC2 – 2020-Low

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

  • Installed Conventional Capacity:

59 743MW

  • Yearly Peak Demand:

48 315MW

  • Equivalent Firm Capacity:

2256 MW

  • Capacity Credit:

22,6%

  • Corrected CC:

25,1 %

  • Average capacity factor of wind generation:

32,0%

  • Average capacity factor during full load hours:

35,8%

  • Capacity reduction factor CR:

0,63 Study Results – SC2 – 2020-High

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

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Sensitivity Studies – Up to 25 000MW of Wind Generation

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Capacity Credit Studies - Summary

  • Capacity credit of wind generation in South Africa will be between 23%

and 27% for installed wind capacities up to 10 000MW until 2020.

  • With increasing penetration levels, capacity credit of wind generation

is generally reducing.

  • In the presented studies, the 2020 wind farm sites have better wind

conditions, therefore capacity credit remains high, also in 2020 scenarios.

  • Considering the limited availability of coal fired power plants (90%),

the effect on generation adequacy is equivalent to coal fired power stations with an installed capacity between 25% and 30% of the installed wind capacity.

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

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Part 2: Impact of Wind Generation on Operational Aspects

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Purpose and Scope of Studies

  • Visualisation of typical variations of wind generation
  • Identification of worst-case situations with regard to

– Ramp-up and ramp-down situations – Peak load situations – Situations with minimum load

  • Input data:

– Time series of wind speeds (hourly resolution, same as capacity credit) – Generic power curve – Forecast of time series of the load for 2015 and 2020 (hourly resolution)

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

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Typical Situation in Winter 2015

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

5000,0 4700,0 4400,0 4100,0 3800,0 3500,0 2000,0 1600,0 1200,0 800,00 400,00 0,0000 x-Axis: TimeSeries: Hour of year in h TimeSeries: Total Wind Generation in MW 5000,0 4700,0 4400,0 4100,0 3800,0 3500,0 5.00E+4 3.75E+4 2.50E+4 1.25E+4 0.00E+0

  • 1.25E+4

x-Axis: TimeSeries: Hour of year in h TimeSeries: Total Load in MW TimeSeries: Total Residual Load in MW TimeSeries: Total Wind Generation in MW

DIgSILENT

Typical Situation in Winter 2020-High (10000MW int. Wind)

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

5000,0 4700,0 4400,0 4100,0 3800,0 3500,0 1.00E+4 7.50E+3 5.00E+3 2.50E+3 0.00E+0

  • 2.50E+3

x-Axis: TimeSeries: Hour of year in h TimeSeries: Total Wind Generation in MW Y = 0,000 MW Y =10000,000 MW 5000,0 4700,0 4400,0 4100,0 3800,0 3500,0 8.00E+4 6.00E+4 4.00E+4 2.00E+4 0.00E+0

  • 2.00E+4

x-Axis: TimeSeries: Hour of year in h TimeSeries: Total Load in MW TimeSeries: Total Residual Load in MW TimeSeries: Total Wind Generation in MW

DIgSILENT

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Typical Situation in Summer 2015

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

8700,0 8360,0 8020,0 7680,0 7340,0 7000,0 2000,0 1600,0 1200,0 800,00 400,00 0,0000 x-Axis: TimeSeries: Hour of year in h TimeSeries: Total Wind Generation in MW 8700,0 8360,0 8020,0 7680,0 7340,0 7000,0 5.00E+4 3.75E+4 2.50E+4 1.25E+4 0.00E+0

  • 1.25E+4

x-Axis: TimeSeries: Hour of year in h TimeSeries: Total Load in MW TimeSeries: Total Residual Load in MW TimeSeries: Total Wind Generation in MW

DIgSILENT

Typical Situation in Summer 2020-High (10000MW int. Wind)

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

8700,0 8360,0 8020,0 7680,0 7340,0 7000,0 10000, 8000,0 6000,0 4000,0 2000,0 0,0000 x-Axis: TimeSeries: Hour of year in h TimeSeries: Total Wind Generation in MW 8700,0 8360,0 8020,0 7680,0 7340,0 7000,0 8.00E+4 6.00E+4 4.00E+4 2.00E+4 0.00E+0

  • 2.00E+4

x-Axis: TimeSeries: Hour of year in h TimeSeries: Total Load in MW TimeSeries: Total Residual Load in MW TimeSeries: Total Wind Generation in MW

DIgSILENT

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Individual vs. Global Wind Generation (2020-High)

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

2900,00 2800,00 2700,00 2600,00 2500,00 2400,00 [-] 1,20 0,90 0,60 0,30 0,00

  • 0,30

TimeSeries: Total Wind Generation in p.u. (base: 10000,00 MW) TimeSeries_Wind: Total Wind Generation in p.u. (base: 250,00 MW) TimeSeries_Wind_South: Total Wind Generation in p.u. (base: 200,00 MW)

DIgSILENT

Scenario 3 – 2020/High Wind – Ramp Rates

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

25,00 20,00 15,00 10,00 5,00 0,00 9000,00 6000,00 3000,00 0,00

  • 3000,00
  • 6000,00

x-Axis: TimeSeries: Proability (Duration Curves) in % TimeSeries: Hourly Load Variation (up) in MW/h TimeSeries: Hourly Load Variation (down) in MW/h TimeSeries: Hourly Wind Variation (up) in MW/h TimeSeries: Hourly Wind Variation (down) in MW/h TimeSeries: Hourly Residual Load Variation (up) in MW/h TimeSeries: Hourly Residual Load Variation (down) in MW/h

DIgSILENT

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Studies – Summary and Conclusions

  • Capacity credit of wind generation in South Africa can be expected to

be in a range of around 25% or higher depending on results of studies that are currently under way.

  • Hourly ramp-up and ramp-down rates of the residual load are

comparable to the corresponding ramp-rates of the system load (without wind generation).

  • There are no considerably increased dynamic performance

requirements for the existing thermal power plants in South Africa resulting from wind generation with up to 10000MW of installed capacity.

  • Main impact on system operation will result from limited predictability

not from actual load or wind variations. Corresponding studies are recommended.

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

“DENA-Grid-Study” (Dena 1 – Study) Integration of Onshore and Offshore Wind Energy into the German Power System – Planning Study 2003 - 2020

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

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PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

German Power Transmission System

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Dena II-Study (Released 11/2010)

  • Studied time frame: 2015-2020
  • Study execution time: 2007-2011
  • Assumptions mainly based on 2007/2008, some of them not valid any

more (e.g. solar power, time frame for nuclear power face-out)

  • Main assumptions:

– Load decreases by 8% until 2020 – Installed onshore wind capacity 2020: 37 000MW – Installed offshore wind capacity 2020: 14 000MW – Installed PV capacity 2020: 17 900MW – Total contribution of renewable energies to electricity demand 2020: 39%

  • All references: Final report Dena II study.
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PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Dena 2 - Scope of Work

  • Assessment of required grid expansion
  • Use of high temperature conductors
  • Use of temperature monitoring
  • Demand-side management
  • Benefits of the use of storage

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Methodology

  • Definition of three base scenarios with regard to storage
  • Definition of three scenarios considering different conductor

technologies.

  • Time series of wind generation with regional resolution and 15min

time resolution.

  • Market model for calculating unit commitment and economic dispatch.
  • Simplified load flow analysis based on regional model and PTDFs
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PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Methodology – regional model for network analysis

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Required Grid Expansion (and cost)

  • Grey: Required length of new overhead lines
  • Blue: Required length of new underground cables
  • Yellow: Annualized costs
  • FLM: With temperature monitoring
  • TAL: High temperature conductors
  • Hybrid: Overhead lines/underground cables
  • HGÜ-VSC: HVDC-VSC
  • GIL: Gas insulated lines

Billion Euro/year Length in km

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PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Other Results and Observations

  • Storage for reducing required grid expansions:

– No significant benefit if storage is operated according to existing market rules.

  • Use of DSM:

– Significant reduction of required load following reserve (by up to 60% max. reserve power) – Reduction of required peak capacity (e.g. gas turbines): around 800MW

  • Increase of load following reserve:

– Because of improved wind prediction, the required load following reserve will not considerably increase until 2020.

Outlook: Determination of the Maximum Possible Installed Wind Generation Capacity in the System of Panama (Start: 2011)

DIgSILENT GmbH

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

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PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Studies for Panama – Scope of Work

  • DIgSILENT is contracted by the ministry of energy of Panama and

ETESA (TSO).

  • Studied time frame: until 2021
  • Phase 1: Grid integration studies

– Steady state (load flow/short circuit) – Dynamic studies (Transient, oscillatory and frequency stability studies)

  • Phase 2: System performance:

– Capacity credit – Impact on required spinning reserve

  • Status: studies have just started

PowerFactory User's Group Meeting 2011 and DIgSILENT Pacific 10th Anniversery, Melbourne February 24-26, 2011

Thank You Markus Pöller mpoeller@digsilent.de DIgSILENT GmbH Heinrich-Hertz-Str. 9 72810 Gomaringen www.digsilent.de