a balanced scorecard approach for the enhancement … · a balanced scorecard approach for the...

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Frankfurt (Germany), 6-9 June 2011

Presented by: Dr. Worawit Tayati

W.Tayati and G.Pack – Australia – Session 4 – Paper ID 0928

A BALANCED SCORECARD APPROACHFOR THE ENHANCEMENT OF

DISTRIBUTED RENEWABLE PENETRATION LIMIT IN ISOLATED NETWORKS

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IntroductionProblem definitionMethodologyStudy resultsConclusionsDiscussion


Outlines

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Horizon Power – Who are we?

Vertically integrated State ownedService regional towns and remote communities2.3 Million sq.km43,000 customersExcluding the South West Excluding the South West Interconnected System Interconnected System (SWIS) ~700,000 (SWIS) ~700,000 custcust..

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Our service area

30 isolated systems(~0.2 – 30MW)

The North West Interconnected System NWISNWIS(~500MW)

Fuel mix – Gas, dieselHydro - North East Wind - coastalSolar PV – inland

Controlled and centralised RE systems

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PV/Diesel/Flywheel hybrid systemMarble Bar – 300kWp PV with Tracking

87% instant. penetration

30% energy penetration

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Integration of Wind - Esperance

300kWp with Tracking system

80% penetration

Two wind farms – Total ~ 5.6MW

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GS416

D505CS1

M43D38

x

NF73Daylup Fdr Myrup Fdr

Gibson Fdr

144KM

154KM

156KM

133KM

- 33kV Network

- ~ 22MW peak demand

- 7x 5MW Gas turbine

- ~ 2500 HV cct.kms

LARGE TOWN

(ESPERANCE)

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Our Strategy Wheel

Cost of energy0.23 - 1.68 $/kWh

GHG Emission 0.68 kgCO2e/kWh

Reliability (/yr/cust.)SAIFI -2.43 (6.6*)SAIDI-162 (290*min)

*Target

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IntroductionProblem definitionMethodologyCase study resultsConclusionsDiscussion


Outlines

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Drastic increase in PV installationsexceeding current limitsAbundant solar resourcesDecreasing PV panel costGenerous Government Incentives

RECs - capital cost subsidy FiTs (40c/kWh) - net feed-in


Problem & Drivers

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System reliability concernSmall, isolated systemsLow fault level, low inertiaNo other sources of supplyExtensive HV overhead networks

LV / MV voltage rise issueEvidence of customer PV inverters trip offLV network operating voltage sets too high


Technical Issues

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IntroductionProblem definitionMethodologyCase study resultsConclusionsDiscussion


Outlines

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Reviewing existing penetration limitStability and network design

Identifing enhancement strategiesPower station and network

Assessing - balanced scorecardStrategy wheel, technical, commercial aspects

Validating – a case study


Methodology

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Supply Quality = PQ + Reliability

Power station (P/S) limit : reliabilityStep load < unit rating (N+1 spinning reserve)Stand alone = no other sources of supply

Network limit : power quality (PQ)LV PV <20% of Tx rating – islandingLV/MV voltage rise


Existing limits

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PV limit is the minimum of the followings:50% smallest generating unit15% of peak demand – diesel generation10% of peak demand – gas generation

And :De-rating of PV output due to temperature and inverter efficiency by ~70%


Rule of Thumb

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Power quality (PQ)Network reinforcement (NR)PV inverter sophistication - output curtialment

ReliabilityUnder Frequency Roll Off (UFRO)Extra spinning reserve (Ex SR) + PV forecastPV Fault Ride Through (FRT)Distributed UFLS - demand responseEnergy Storage (ES) & AMI


Enhancement strategies

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Economics Environmental Social - Customer equityTechnical

EffectivenessUptake

Commercial IPP contracts <10% RE


A Balanced Scorecard (BSC)

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Selection Criterion:PV penetration exceeding current limitsHorizon Power owned P/SNew P/S under construction

Opportunity to implement innovative enhancement strategies

Centralised wind energy integration envisaged


CASE STUDY - Carnarvon

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IntroductionProblem definitionMethodologyAnalysis of resultsConclusionsDiscussion


Outlines

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Network Fault Studies

FDR 6 50 kmsEOL

FDR 5

5 kms 20 kms 5 kms 20 kms

22kV SWBDF2 F3 F4

FDR4

FDR 3

FDR 2EXISTING P/S NEW P/S

FDR 1EXP Feeder 1

EXP Feeder 26.6kV 11kV

22kV SWBD

F1

G G

Impact of network faults on distributed PV

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Network Fault Studies

Faults near to P/S, voltage depressionFaults away from P/S, system frequency dips (due to high R/X ratio)PV inverters may trip on UV or UF

““Adverse impacts on power station stabilityAdverse impacts on power station stability””

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PV Fault Ride Through

Investigate effects on PV of network faults followed by feeders trip and recloseDetermine effectiveness of PV FRT functionality

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““PV FRT enhances system reliabilityPV FRT enhances system reliability””

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BSC for Carnarvon

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Network Reinforcement (NR) recommendedUFRO recommended for new P/SPV FRT considered, improve reliability

Proven technology, uptake?UFLS – uptake?, effectiveness? Energy storage – cost barrierAMI – uptake?, costExtra SR – commercial contract, more emission, cost


Summary – Case Study

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Spinning reserve(Based on N+1 operating philosophy)

PV limit based on 1.6MW Spinning Reserve

0.000

1

2

3

4

5 6 7 8 9 10 11 12 13 14 15 16 17Network Load (MW)

SR

(MW

)

Loss of PV PV GenerationLoss of Gen

Loss of Total PV

Loss of Single Unit

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PV limit based on 1.6MW Spinning Reserve

2.00

-1

0

1

2

3

5 6 7 8 9 10 11 12 13 14 15 16 17

Network Load (MW)

SR

(MW

)Loss of PV PV GenerationLoss of Gen

Possibility of Higher PV Penetration

Loss of Total PV

Loss of Single Unit

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Outlines

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Small power system supply quality is susceptible to level of distributed PV penetration Expectation to accommodate distributed PVOur deterministic limits based on spinning reserve may be too conservative There are opportunities to increase decentralised PV penetration limits using a risk based probabilistic approach e.g.

Probability of not all PV disconnecting following faultsProbability of fault frequency (fault rate)Probability of PV output not at installed capacity (temperature, cloud cover, incident angle, etc.)


Conclusions

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Outlines

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QUESTIONS?

THANK YOU FOR YOUR ATTENTION

a balanced scorecard approach for the enhancement … · a balanced scorecard approach for the...

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