impact of cross-border-trade on the ucte system

CESI

Presentation to the Presentation to the 7th International Workshop on EPCC7th International Workshop on EPCCOrtisei, May 2003Ortisei, May 2003

Impact of Cross-Border-Trade onImpact of Cross-Border-Trade onthe UCTE system: development ofthe UCTE system: development ofa sensitivity model and test casea sensitivity model and test caseon the Italian Interconnectionon the Italian InterconnectionPaola BresestiPaola BresestiBU T&D NetworksBU T&D NetworksCESI SpACESI SpA

This research was supported by the Italian Ministry of Industry, Commerce and Handicraft within the activity This research was supported by the Italian Ministry of Industry, Commerce and Handicraft within the activity Ricerca di Sistema DM 17/04/2001and 28/02/2003. The author thanks Prof. P.Marannino and F.Zanellini from Ricerca di Sistema DM 17/04/2001and 28/02/2003. The author thanks Prof. P.Marannino and F.Zanellini from UniversitUniversitàà degli Studi di Pavia for their role in the research. degli Studi di Pavia for their role in the research.

CESI 1

ForewordForeword

The Cross Border Exchanges in the UCTE system affect theThe Cross Border Exchanges in the UCTE system affect thetransmission systems of countries not directly involved in thetransmission systems of countries not directly involved in thetransactiontransactionss..

These effects, normally grouped under the heading of "Transit Flows",These effects, normally grouped under the heading of "Transit Flows",can be explained either by the geographic position of the indirectlycan be explained either by the geographic position of the indirectlyinvolved systems or by the physical laws governing the flow ofinvolved systems or by the physical laws governing the flow ofelectricity in meshed systemselectricity in meshed systems. . In this last case the termIn this last case the termss ““parallel flowparallel flow””and and ““loop flowloop flow”” are often are often used.used.

The great concern in the analysis of the "transit flows" is related to theThe great concern in the analysis of the "transit flows" is related to thecalculation of the additional costs sustained by the TSOs for hostingcalculation of the additional costs sustained by the TSOs for hostingtransits as well as to the assessment of their effects on the systemtransits as well as to the assessment of their effects on the systemsecurity.security.

As consequence of the rapid increase in bulk energy transactions,As consequence of the rapid increase in bulk energy transactions,which which comescomes from the gradual opening of a common electricity market from the gradual opening of a common electricity marketin Europe, the development of suitable tools for the assessing thein Europe, the development of suitable tools for the assessing theimpact of CBT in the UCTE system is therefore of topical interest.impact of CBT in the UCTE system is therefore of topical interest.

CESI 2

Definitions of Definitions of parallelparallel flows flowsThe exchange programs between two neighbouring areas equal the powerThe exchange programs between two neighbouring areas equal the powerflow on the corresponding interconnection corridor only for the ideal case of aflow on the corresponding interconnection corridor only for the ideal case of aradial interconnection.radial interconnection.

For well meshed network, the flow between two neighbouring areas A and BFor well meshed network, the flow between two neighbouring areas A and Bconsists of the superimposition of two components:consists of the superimposition of two components:–– a a Direct FlowDirect Flow (DF) from A to B; (DF) from A to B; –– a a Parallel FlowParallel Flow (PF) crossing the neighbouring system C not involved in the (PF) crossing the neighbouring system C not involved in the

transaction. The entity of the term PF depends on the topology andtransaction. The entity of the term PF depends on the topology and on on the theoperational conditions of the network.operational conditions of the network.

AA CC

BB

DFDFPFPF

PFPF

CESI 3

Remarkable Transit Flows in Remarkable Transit Flows in 20022002BelgiumBelgium

–– the Belgian network the Belgian network waswas heavily loaded by unidentified flows in direction South to heavily loaded by unidentified flows in direction South toNorth. These flows are mainly caused by French export in addition to exchanges fromNorth. These flows are mainly caused by French export in addition to exchanges fromSwitzerland to Germany, which are partly passing trough both Belgian borders.Switzerland to Germany, which are partly passing trough both Belgian borders.

SwitzerlandSwitzerland–– tthe opening of the electricity markets around Switzerland has strongly influenced thehe opening of the electricity markets around Switzerland has strongly influenced the

production pattern in and around Switzerland. This has led to an important increase ofproduction pattern in and around Switzerland. This has led to an important increase ofthe transit flows crossing Switzerland during the night and in the week-end.the transit flows crossing Switzerland during the night and in the week-end.

AustriaAustria–– the liberalisation process in Austria lead to increased load flows on the 220 the liberalisation process in Austria lead to increased load flows on the 220 kkV gridV grid

between the north and the south of Austria. In some cases the (n-1) criteria could notbetween the north and the south of Austria. In some cases the (n-1) criteria could notbe fulfilled.be fulfilled. In addition on some days during the winter period remarkable simultaneousIn addition on some days during the winter period remarkable simultaneousload variations of power plants in France and Germany resulted in a significantload variations of power plants in France and Germany resulted in a significantincrease of the load flow on these lines and aggravated the tight load flow situation.increase of the load flow on these lines and aggravated the tight load flow situation.

ItalyItaly–– The operation of the Italian Eastern border recorded high power flows, mainly on theThe operation of the Italian Eastern border recorded high power flows, mainly on the

second half of the year, sometimes with impact on the respect of the security criteria.second half of the year, sometimes with impact on the respect of the security criteria.Exchange values were much larger than the scheduled ones. These operatingExchange values were much larger than the scheduled ones. These operatingconditions were originated by remarkable conditions were originated by remarkable parallelparallel flows flows on the northern interconnectionon the northern interconnection..

Data provided by UCTE

CESI 4

The The Italian CaseItalian Case

TThe he permanent permanent congestion on the congestion on the northern northern Italian border isItalian border isthe most severe and the most discussedthe most severe and the most discussed in Europe in Europe

This congestion has two main reasons :This congestion has two main reasons :–– the the structural asymmetry of the Italian generation structural asymmetry of the Italian generation setset in comparison in comparison

to the other European countriesto the other European countries - - consequence of different nationalconsequence of different nationalenergy policies in the pastenergy policies in the past;;

–– the the crucial role of the imported energy for the crucial role of the imported energy for the wholesale energywholesale energymarket.market.

Under these conditionsUnder these conditions,, the deviations of the power flows the deviations of the power flowsdue to unforeseen parallel flow phenomena are particularlydue to unforeseen parallel flow phenomena are particularlycritical and critical and can can dangerously affect system securitydangerously affect system security

CESI 5

The Italian The Italian Northern Northern interconnectionsinterconnections

220 kV circuitThe ItalianInterconnectedSystem

400 kV circuit

400 kV double circuit

France

Italia

Slovenija

AustriaSwitzerland

CESI 6

Winter NTC ValuesWinter NTC Values

Winter NTC of the Italian interconnection

[MW] Year 2003

FRANCE 2650 (42%)

SWITZERLAND 3050 (48%)

AUSTRIA 220 (3%)

SLOVENIJA 380 (6%)

TOTAL 6300

CESI 7

The Parallel-Flow across the The Parallel-Flow across the Italian-Italian-Slovenian borderSlovenian border

Since 1999 the power flows across the Italian-Slovenian border haveSince 1999 the power flows across the Italian-Slovenian border havebeen significantly higher than the corresponding NTC value (380 MWbeen significantly higher than the corresponding NTC value (380 MWduring winter)during winter)

Even though it is quite difficult to establish the real reasons behindEven though it is quite difficult to establish the real reasons behindthese high flows, these high flows, somesome main influencing factors can be detected: main influencing factors can be detected:–– the parallel-flow of the increasing exported energy from the Ex-Centrelthe parallel-flow of the increasing exported energy from the Ex-Centrel

countries;countries;–– the progressive increase of the NTC across the Italian border;the progressive increase of the NTC across the Italian border;–– more generally, the rapid increase in bulk energy transactions in Europemore generally, the rapid increase in bulk energy transactions in Europe..

The phenomenon is particularly stressed The phenomenon is particularly stressed during the night and the week-during the night and the week-endend, when there is large availability of energy supply., when there is large availability of energy supply.

On the contrary it is emphasised that during full load hours the powerOn the contrary it is emphasised that during full load hours the powerflows are very close to the programmed onesflows are very close to the programmed ones..

CESI 8


Source GRTN

CESI 9


Source GRTN

CESI 10

Annual Exported Energy from EX-CENTREL Countries

0

5000

10000

15000

20000

25000

30000

1999 2000 2001 2002Year

[GW

h]

Annual Exported Energy from Ex-Centrel CountriesAnnual Exported Energy from Ex-Centrel Countries

Data provided by UCTE and processed by Cesi

CESI 11


Data provided by GRTN and processed by Cesi

The yearly peak of the power flowing across theThe yearly peak of the power flowing across theItalian-Italian-Slovenian border exceeded 1600 MW in 2002Slovenian border exceeded 1600 MW in 2002

Power flow across the Italian-Slovenian border Yearly peak

0200400600800

10001200140016001800

1999 2000 2001 2002

[MW

]

CESI 12


Power flows across the Italian-Slovenian borderHours of the year in which the power flow exceeds 1000 MW

0100200300400500600700800900

1000

1999 2000 2001 2002

[Hou

rs]


CESI 13

SSensitivity indicatorsensitivity indicatorsInjection Shift Distribution Factor (ISDF – ISF)Injection Shift Distribution Factor (ISDF – ISF): sensitivity of the power: sensitivity of the powerinjection in the node injection in the node nn on the power flow on the line on the power flow on the line ll (depends on the (depends on theslack bus selection):slack bus selection):

Power Transfer Distribution Factor (PTDF)Power Transfer Distribution Factor (PTDF): sensitivity on the power: sensitivity on the powerflow on the line flow on the line ll of a power exchanges between nodes of a power exchanges between nodes mm (sending) (sending)and and nn (receiving): (receiving):

Line or Generator Outage Distribution Factor (L or G ODF)Line or Generator Outage Distribution Factor (L or G ODF): sensitivity: sensitivityon the power flow on the line on the power flow on the line hkhk of the trip of the line of the trip of the line rsrs or for the trip of or for the trip ofgenerator in the bus generator in the bus nn::

n

lnl P

T∆∆

=,ψ

nlmlnmlPTDF ,,),(, ψψ −=

0,rs

hkrshk

TT∆

=α 0,n

hknhk

PTs ∆

=

CESI 14

The developed The developed procedureprocedureThe aim of the developed The aim of the developed procedureprocedure is to asses the parallel-flow is to asses the parallel-floweffects on different interconnected areas due to a single bilateraleffects on different interconnected areas due to a single bilateralexchange between a "source" and a "sink" located in twoexchange between a "source" and a "sink" located in twodistinct areasdistinct areas

an AC based PTDF sensitivity modelan AC based PTDF sensitivity model, above defined, is, above defined, isimplemented;implemented;

the total sensitivity of each border results from the sum of thethe total sensitivity of each border results from the sum of thesensitivities of the corresponding interconnecting lines;sensitivities of the corresponding interconnecting lines;

The procedure The procedure performs the automatic comparison between theperforms the automatic comparison between thecomputed computed sensitivities sensitivities and and numerical numerical load flow resultsload flow results;;

tthe model was tested on the UCTE he model was tested on the UCTE network in a network in a forecastedforecastedwinter winter scenario 2002scenario 2002

CESI 15

UCTE Forecasted Winter Scenario 2002UCTE Forecasted Winter Scenario 2002

Belgium

(-1676 MW)

Netherlands (-2500 MW)

Germany (-1173 MW)

Poland (+1608 MW)

Czech Rep. (+1344 MW)

France (+7203 MW)

Switzerland (+2534 MW)

Austria (-340 MW)

Slovenia (+103 MW)

Slovak Rep. (+351 MW)

Hungary (-176 MW)

Croatia (-194 MW)

Italy (-5989 MW)

+1787 MW

+1654 MW

+495 MW

+2343 MW

+111 MW

+2389 MW +58 MW

+200 MW +182 MW

+1584 MW

+1330 MW

+286 MW

+973 MW

+336 MW

+804 MW

+71 MW +293 MW

+341 MW +504 MW

+139 MW

+2758 MW +305 MW

+ 583 MW Spain (-846 MW)

Portugal (+197 MW)

+924 MW+197 MW

Marocco (-275 MW)

+275 MW


CESI 16

Transaction Transaction from from France France (S-E) to(S-E) to ItalyItaly (N-W) (N-W)

RONDISSONE (-100 MW)

Exchange 92%

Italy (-5989 MW)

Belgium (-1676 MW)


Germany (-1173 MW)

Poland (+1608 MW)

Czech Rep.

(+1344MW)

France (+7203 MW) TRICASTIN

(+100 MW)


Austria (-340 MW)

Slovenia (+103 MW)

21 (21.1)2 (1.4)


Hungary (-176 MW)

Croatia (-194 MW)

2 (1.8)

2 (1.9)

54 (54.4)

32 (30.1)

2 (1.4)

4 (3.4)

1 (0.9)

7 (7.6)

2 (2.8)

4 (3.8)

1 (0.5)

7 (8)

7 (7.2)

7 (7.8)

7 (6.7) 1 (0.9)

2 (2.)

1 (0.4)

1 (0.3)2 (1.4)

2 (1.6)

CESI 17

TTransaction ransaction from from Czech Rep.Czech Rep. (S-E) (S-E) toto ItalyItaly (N) (N)

BAGGIO (-100 MW) Exchange = 94%

Italy (-5989 MW)

Belgium (-1676 MW)


Germany (-1173 MW)

Poland (+1608 MW)

Czech Rep.(+1344 MW) SLAVETICE

(+100 MW) Exchange = 100%

France (+7203 MW)


Austria (-340 MW)

Slovenia (+103 MW)

3 (3.0)5 (5.5)

12 (10.4)

12 (11.8)

11 (11.2)

9 (2.2)

11 (9.2)


2 (1.4)

15 (16.5)

Hungary (-176 MW)

12 (16.3)

Croatia (-194 MW)

15 (14.3)

15 (16.4)

22 (21.3)

47 (45.1)

6 (6.1)19 (19.2)

33 (36.6)

3 (1.8)

12 (14.8)

43 (46.3)

29 (29.4)

10 (10.8)

6 (7.0)

CESI 18

Transaction Transaction from from HungaryHungary (N-E) (N-E) toto ItalyItaly (N) (N)

BAGGIO (-100 MW)

Exchange = 90%

Italy (-5989 MW)

Belgium (-1676 MW)


Germany (-1173 MW)

Poland (+1608 MW)


France (+7203 MW)


Austria (-340 MW)

Slovenia (+103 MW)

2 (2.5)

0 (0)

12 (10.1)

11 (10.8)

13 (14.0)

10 (8.9)


7 (6.5)39 (37.9)

Hungary (-176 MW TISZA (+100 MW) Exchange = 96%

47 (42.0)

Croatia (-194 MW)

25 (24.3)

25 (27.3)

19 (19.3)

43 (41.1)

5 (5.7)23 (24.0)

0 (3.0)

24 (26.1)

11 (12.8)

33 (35.6)

26 (26.9)

10 (10.2)

7 (8.2)

6 (0.)

CESI 19

Transaction Transaction from middle from middle Poland Poland toto ItalyItaly (N) (N)

Belgium

(-1676 MW)


Germany (-1173 MW)

Poland (+1608 MW)

ROGOWIEC(+100 MW)

EXCHANGE 95%


France (+7203 MW)


Austria (-340 MW)

Slovenia (+103 MW)

3 (3.4)4 (3.7)

35 (36)

46 (54)

11 (10)


14 (15.2)6 (7.2)

Hungary (-176 MW)

19 (21.6)

Croatia (-194 MW)

13 (12.7)

13 (14.2)

BAGGIO (-100 MW) EXCHANGE 88%

Italy (-5989 MW)

21 (20.5)

46 (42.8)

5 (5)

16 (16.1)

14 (15.7)5 (5.7)

13 (14)

26 (28)28 (28.7)

10 (10)

13 (1

2.5)

13 (12.7)

1 (0.68)

CESI 20

Transaction Transaction from from Switzerland Switzerland (N-W) to (N-W) to GermanyGermany (N-E) (N-E)

Italy (-5989 MW)

Belgium (-1676 MW)


Germany (-1622 MW) WOLMIRSTEDT (-100 MW) Exchange 98 %

Poland (+1608 MW)


France (+7408 MW)

Switzerland (+2501 MW) MUEHLEBERG (+100 MW) Exchange 100%

Austria (-63 MW)

Slovenia (+103 MW)

1 (1

.6)

8 (8.5)

6 (9.3)


2 (2.9)

Hungary (+75 MW)

Croatia (-194 MW)

4 (4.6)

5 (5.3)

3 (4.6)

6 (7.2)

5 (6

.6)

3 (1)

3 (0.6)

5 (4.5)

8 (7.3)

2 (5

.5)

20 (1

8.7)

19 (1

9.5)

16 (15.7)

46 (4

6.3)

20 (22.7)

3 (4)

6 (7

)

41 (42)

6 (6)

CESI 21

Conclusions and futureConclusions and future works works

TThe results of the test showed a close correspondence betweenhe results of the test showed a close correspondence betweenthe analytical and the numerical values.the analytical and the numerical values.

For transactions between EuropeFor transactions between Europe and and Italy, according to theItaly, according to theexamined UCTE scenario, it is emphasised that:examined UCTE scenario, it is emphasised that:–– The Swiss border seems to do most of the work for a wide range ofThe Swiss border seems to do most of the work for a wide range of

transactions;transactions;–– There are There are remarkableremarkable effects on the Italian-Slovenian border when effects on the Italian-Slovenian border when

the sources of the transaction are inside the ex-Centrel block.the sources of the transaction are inside the ex-Centrel block.

The next steps of the work are:The next steps of the work are:–– To To autoautomatemate the procedure; the procedure;–– To To assess the extent to which assess the extent to which thethe operating conditions canoperating conditions can

remarkably remarkably affect the sensitivity values;affect the sensitivity values;–– To To define source and sink sub-areas grouping together busses withdefine source and sink sub-areas grouping together busses with

similar parallel flow effects on specific borders.similar parallel flow effects on specific borders.

impact of cross-border-trade on the ucte system

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