Impacts of Quality Improvement Incentives on Automation

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C I RC I RC I RC I R E DE DE DE D 20th International Conference on Electricity Distribution Prague, 8-11 June 2009Paper 0141

CIRED2009 Session 5 Paper No 0141

IMPACTS OF QUALITY IMPROVEMENT INCENTIVES ON AUTOMATION

INVESTMENTS IN THE FINNISH NEW REGULATION MODEL

Henry LGLAND Kimmo KAUHANIEMI Tapio HAKOLA Juha RINTAMKIUniversity of Vaasa Finland University of Vaasa Finland ABB - Finland Vaasan Shkverkko - [email protected] [email protected] [email protected]@vaasansahko

verkko.fi

ABSTRACT

During the second regulatory period of 2008-2011

incentives are included into the Finnish regulation model

which allows higher profits for the network owners for

properly allocated network investments leading to lower

operation and interruption costs. In this paper the

economical benefit and payback time of different

automation schemes in two typical Finnish rural medium

voltage (MV) distribution feeders are studied. The

electricity distribution reliability indices, total outage cost,

outage cost saving and payback time for different

automation schemes with different numbers and locations

of automated distribution substations were calculated.

INTRODUCTION

Finnish rural MV distribution feeders are usually protectedby the reclosers of the primary distribution substation only.Centrally located branching points of the feeders may beequipped with remote controlled switches to reduce faultlocating, isolation and restoration times. Using remotecontrolled circuit-breakers instead of switches also allowsfeeders to be sectionalised. Sectionalisation means dividinga feeder into sections in order to isolate faults and minimizethe section of the feeder circuit that is put out of service.Thus the cost of non-delivered energy (NDE) and auto-reclosing (AR) are reduced.

This integration of remote control and protection isachieved by using ABB's compact three-phase vacuum

recloser OVR-3, which is remotely controlled over aGeneral Packet Radio Service (GPRS) connection. Theearth-fault current is derived from the residual current of thethree phase-currents. A remote monitoring and control unittype REC 52_ is used for remote and local control of theline recloser and for protection, fault indication, conditionmonitoring and supervision of the downstream feedersection. According to the performed laboratory tests, anearth-fault protection sensitivity of 1.2 A primary value isachieved, which is of the same order as the sensitivity of thesubstation recloser earth-fault protection.

The new Finnish regulation model

According to the guidelines for the Finnish secondregulatory period of 2008-2011 the quality of the electricitydistribution influences the economy of distribution

companies in two ways. First, the regulation authority sets acompany-specific efficiency improvement obligation, whichconsists of a company-specific and a general improvementtarget. Second, the regulation authority calculates areasonable profit level for each distribution company, thusregulating the price setting of the companies. Thus

incentives are included into the Finnish regulation model,which allow higher profits for the network owners whoallocated network investments properly, leading to loweroperation and interruption costs.

The zone concept

Apart from sectionalisation the zone concept includesseveral other means of increasing the number of protectionzones within the distribution areas of a primary distributionsubstation. By increasing the primary distribution substationdensity with light 110 kV substations the effects ofinterruptions and voltage dips are restricted and themagnitude of the earth-fault currents is reduced. By

increasing the number of protection zones with switchingsubstations and line reclosers auto-reclosings are carried outdeeper in the network and the protection zones diminish.Creating new protection zones by using the 1000 Vdistribution system limits the influence of faults located onthe feeder laterals to the laterals. Enhancing feederautomation with fault location capability reduces faultduration. Increasing remote control of switches indistribution substation results in enhanced fault restoration.In this paper the economic benefit of integrated protectionand remote control is investigated in a case study

CASE STUDY

Two feeders in the distribution area of VaasanShkverkko, a distribution company on the Finnish westcoast, were chosen for the case study. Details of the studiedfeeders and the main calculation parameters are presented inTables 1-4. Electricity distribution reliability indices, totaloutage cost, outage cost saving and payback time fordifferent automation schemes with different number andlocation of automated distribution substations werecalculated. The results were calculated for feeders with noautomation, with current remote control facilities and withcurrent remote control facilities and possible future cost-effective sectionalisation schemes. The benefits of possiblefuture automation schemes were evaluated with regard tothe improvements of the distribution substation reliability


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indices T-SAIFI and T-SAIDI and the payback time of theautomation investments, of which the most cost-effectivesolution was chosen for the pilot installation.

Table 1. Characteristics of the two feeders studiedcompared to average values for Finnish rural areadistribution feeders. Abbreviations: UGL= undergroundinglevel, DSS= distribution substation, NOP= normally openpoint.

Fee-der

WGWh

PMW

Lkm

UGL%

DSS/km

No.NOPs

F1F2Finland

12.59.4

1.41.1

54.568.631.6

7.86.64.0

0.840.931.0

35

Table 2. Forestry level and outage-related data compared toaverage Finnish rural area feeder values.Frequency 1/100 km, yearFee-

derForestry

HSAR DAR Sust. Interrupt.F1F2Finland

15 %20 %28 %

48.437.537.2

3.02.58.7

8.66.25.4

Table 3. Unit costs of NDE and AR [1].NDE

/ kW / kWhHSAR

/ kWDAR

/ kW1.19 11.9 0.59 1.19

Table 4. Used calculation parameters. Abbreviations:OHL= overhead line, UGC= underground cable, COC=coated overhead cable.

Property Component ValueFault frequency,1/100 km, year

OHLOHL, open fieldOHL, forestUGCCOCDSS

5.372.9410.01.762.00.88

Switching time, h manualremote

1.00.1

Repair time, h OHL, COCUGCDSS

3244

Zone design

Natural locations for line reclosers are downstream of loadcentres, at the interface between underground cables andoverhead lines, in the beginning of branches or laterals andat current remote control sites. According to the principle oflocation the studied feeders were divided in 4-5 zones(Figure 1), and then the characteristics of the zones were

calculated (Table 5). The automation schemes studied arepresented in Table 6.

Feeder F1

R3

R1R2R1C

RC1

RC2

A1429 kW

13 km19 DSS

A2

472 kW8 km16 DSS

B156 kW12 km10 DSS

110/ 20 kV

C377 kW19 km20 DSS

C2

145 kW9 km10 DSS

Feeder F2

B184 kW12 km11 DSS

A2133 kW14 km14 DSS

A1421 kW20 km23 DSS

C1

222 kW14 km16 DSS

RC1

RC3

R1

R3

R2RC4

RC2

110/ 20 kV

Figure 1. Circuit configuration, zone design andcharacteristics of feeders F1 and F2.

Table 5. Characteristics of the zones of the feeders.Length, kmFee-

derZo-ne

Fo-restry%

PkW OHL UGC COC

No.ofDSS

A1 10 428 9.9 3.8 19A2 30 472 8.2 0.3 16B 10 156 12.5 10

F1

C 10 377 19.6 0.2 20Sum 4 1434 50.2 4.3 65

A1 20 421 19.8 0.1 23A2 20 133 9.5 4.4 14B 25 184 12.4 11C1 20 222 11.8 2.1 16

F2

C2 20 145 6.6 1.9 10Sum 5 1104 60.1 4.5 4.0 74

Table 6. Applied automation schemes and symbols.Auto-

mation

Sym-

bol

Description

Remotecontrolledswitches

RC1

RC2

RC12

Remote controlled distributionsubstation RC1Remote controlled distributionsubstation RC2Remote controlled distributionsubstations RC1 and RC2

Remotecontrol-led linerecloser

R1R2R3R12

R1-3

Remote controlled line recloser R1Remote controlled line recloser R2Remote controlled line recloser R3Remote controlled line reclosersR1 and R2Remote controlled line reclosersR1, R2 and R3

Results

The chosen feeders for the study were among the worstperforming feeders of the distribution company partly


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REFERENCES

[1] The Finnish Energy Market Authority (EMA), 2008,

Liite 1 Menetelmt shkn jakeluverkkotoiminnan tuotonmrittmiseksi 1.1.2008 alkavalla ja 31.12.2011pttyvll valvontajaksolla. (Methods for determining theprofit of electricity distribution for the second regulatoryperiod), 29-31, 63-64, available at:http://www.energiamarkkinavirasto.fi/files/liite1_770-873-425-2004.pdf, only in Finnish.

[2] Lakervi E, E.J. Holmes, 1996, Electricity distributionnetwork design, Second edition. Peter Peregrinius Ltd.,London, UK, 70-79.

APPENDIX: Equations used in calculations

Reliability indices

mpmpkSAIFIT i /= , where

impk = number of distribution substation

areas that are influenced by outage imp = total number of distribution substation

areas in the distribution area

= = =

n

i

x

jijij mphmpkSAIDIT 1 1 / , where

n = number of outagesx = number of different outage durationsrelated to a certain outage

ijmpk = number of distribution substation areas

in the areas where the outage duration was ijh

mp = total number of distribution substation


mpmpkMAIFIT i/= , where

ijmpk = number of distribution substation areas

that are influenced by the momentaryinterruption imp = total number of distribution substation


Cost, savings and payback time

The cost of NDE is calculated by means of the cost of thepower and energy not supplied NDEC [2]:

( ) ( )[ ] += jijijijjiNDE PttbtaC , where

i

= average outage rate( )ijj ta and ( )ijj tb are the per-unit cost values for

the power and energy not supplied to the loadpoint j when the outage time is

ijt (e.g./kW and

/kWh)

jP = average power not supplied

The cost of AR CAR is:

+= DiiDHiiHAR cPLcPLC , where

Hc = HSAR unit price

Dc = DAR unit priceH = HSAR frequency per unit length of line

D = DAR frequency per unit length of lineLi = line length of zone iPi = average power of zone i

The total outage cost INTC is:

ARNDEINT CCC +=

The economic benefit of an automation scheme i is:

( ) ( )[ ]iARARijji

CCCCB += 00, where

0jC is the cost of NDE for the basic feeder 0

without automation

ijC is the cost of NDE for the feeder with

automation scheme i

0ARC is the cost of AR for the basic feeder 0

without automation

iARC is the cost of AR for the feeder with

automation scheme i

The payback time iT with the remote controlled linerecloser scheme i is:

( )INTiINTii CCKT = 1/ , where

iK is the investment cost of recloser scheme i

1INTC is the total outage cost in year 2008

INTiC is the total outage cost with recloser

scheme i

Impacts of Quality Improvement Incentives on Automation

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