Loss Reduction Reliability Improvement Hoshi

Feedback Seminar on Energy-efficiency potential in South Africa

Loss Reduction & Reliability yImprovement in Distribution

S tSystemJanuary 2008January 2008

Tokyo Electric Power Company y p y(JICA Study Team)

Koichi HOSHI

Copyright© 2009, Tokyo Electric Power Co, Inc. All rights reserved 1

Image of Distribution LossEnergy Sent-out from HV/MV Substations

Metered End-user Consumption(energy sold)System Loss

Collected BillsUncollected Bills

Bill d E

Technical Loss

Non-technical

LossFinancial

Loss

Billed Energy

(Billed Energy– Collected Bills)

{(Energy Sent from S/S – Billed Energy)– Technical Losses}

Loss


Commercial Loss

Transmission & Distribution Loss

International Comparison of Line Loss(％)(％)

9.1

8

9

10

8.0

5.2

3.8

6.7

4.6

4

5

6

7

8

3.8

1

2

3

4

FY(2002) (2000) (1999) (1998) (2000)

0

TEPCO U.K. U.S.A. FRANCE GERMANY SOUTH AFRICA

(2008)


FY

Transmission & Distribution Loss

(%)TEPCO’s historical trend of Loss

25

30

( )

Newly Installation and Capacity Upgrading of Substations

15

20

T&D Lines Upgrading (3.3kV 6.6kV, 66kV 154kV)

10

15

4.6%

0

5

950

955

960

965

970

975

980

985

990

995

000

005

FY


19

19

19

19

19

19

19

19

19

19

20

20 FY

Types of Distribution System Loss

ConductorResistance Loss

Technical Loss

Transformer Core Loss

Corona Loss or Leakage (very few)

Core Loss

Copper Loss

Mostly losses come from conductor Countermeasures advisable

Non Technical LossI M i

Non-

Mostly losses come from conductor. Countermeasures advisable.

Inaccurate MeteringDefective MeterTampering/Pilferage

technical Loss

C i l L

Financial Financial Loss

Commercial Loss


Financial Loss

Financial LossUncollected Revenue

Countermeasures for Distribution Loss(Focusing on the Technical Loss)

Leveling distribution system loads byLeveling distribution system loads by

network re-configuration(for MV, LV system)

Power factor correction by capacitor placement

Install new feeders

Install new transformers

Build a substationBuild a substation

Re-conductoring

(Replace with larger cross section conductor)


(Replace with larger cross section conductor)

Overview of Countermeasures1. Leveling of distribution system loads

by network re-configuration

•Some loads in the heavy loaded feeder shifted to

Basic Idea

yanother lightly loaded feeder•Sectionalizing switchgear allocation for load shift (new interconnection between feeders may be required)•Optimal switching allocation may be done by distribution

t l i ftsystem analysis software

Comments


•First step for loss reduction with less investment

Image of Load LevelingSubstation B

Substation A

Load 1Load 2 Load 3

Substation B

Feeder B

Load 4

Load 5

MV System Re-configurationFeeder A

Feeder C

Substation C

Load 1 Load 2 Load 3

Substation B

Load 1 Load 2 Load 3

Load 4Substation A

Feeder AFeeder B

Note: Load 4

Load 5Feeder C

After re-configuration, loss reductionin feeder A may have much more impact on the total system loss than the loss increase in feeder B & C.


Substation C

Overview of Countermeasures2. Power factor correction by capacitor placement

•Improvement of power factor reduces power flow in a feederBasic Idea

•Improvement of power factor reduces power flow in a feeder. Thus, system loss reduction achieved

• Power factor improved by compensating the reactive power p y p g p

Ic(Reactive Current)

Image of Reactive Current Compensation

Load

( )

Load Load Load LoadLoadCapacitor

I’c

Reactive Current

IcWithout CapacitorWith Capacitor

I’c Compensation

Copyright© 2009, Tokyo Electric Power Co, Inc. All rights reserved 9Sending

EndReceiving

End

I c

Overview of Countermeasures3 I ll f d / f / b i3. Install new feeders/transformers/substations

Basic IdeaH l d d t b li d b f d th t•Heavy loaded area to be supplied by new feeder so that

existing feeder supplies less loads (for new feeder install,

sometimes ne HV/MV t ansfo me needed)sometimes new HV/MV transformer needed)

•New substation to be built in the center of high load density

area so that existing feeder supplies less loadsarea so that existing feeder supplies less loads

CommentsB ildi f iliti (f d t f b t ti )•Building new facilities(feeders, transformers, substations) requires a certain level of investment. Impact of loss reduction and investment must be carefully considered.


reduction and investment must be carefully considered.

Evaluation of Loss Reduction Measures

Total Cost = Cost of Loss Reduction + (Lost) Economic Value of Energy Loss

High

Cost Cost of Loss Reduction

Optimal point

Cost

(Lost) Economic Value of Energy Loss *

Cost of Loss Reduction(Investment)

0Input of loss reduction measures

of Energy Loss Low

Input of loss reduction measures

When “Cost of Loss Reduction” > “Economic Value of Reduced Energy Loss”, the loss reduction measure is considered feasible


the loss reduction measure is considered feasibleDetermine the most effective measures and their respective input

TEPCO Loss Reduction Experiences

Loss Reduction & Reliability Improvement in Jamaica

Cli M b i J i P bli S i (JPS)Client: Marubeni, Jamaica Public Service (JPS)

Period: Aug 2007 – July 2008

Power Distribution System Loss Reduction(Phase II)Power Distribution System Loss Reduction(Phase II)

Client: Electricite du Laos/World Bank

Period: Mar 2007 – Dec 2008 (Phase II)( )

Period: Mar 2004 – Mar 2005 (Phase I)

Feasibility Study on Loss Reduction of Distribution Network

Client: National Electric Power Co. Jordan/JICA

Period: Sep 1999 – Oct 2000


Reliability IndicesSAIDI : System Average Interruption Duration Index

(Annual Average Interruption Duration per Customer)

Σ（Interruption Duration × Number of Interrupted Customers）

Total Number of CustomersSAIDI=

TEPCO = 3 minutes

SAIFI : System Average Interruption Frequency Index (Annual Average Interruption Frequency per Customer)

ΣΣ（Total Number of Interrupted Customers）

Total Number of CustomersSAIFI=


TEPCO = 0. 04 times

Distribution Network in TEPCOT i l M lti Di id d d M lti C t d S t (St d d C fi ti )Typical Multi-Divided and Multi-Connected System(Standard Configuration)

1st. section2nd. section

3rd. section 3rd. section

Feeding Point 1st. section 2nd. section

F di P i t

Feeding Point Distribution Line

OpenOpen

Close

1st section2nd. section

3rd. section

3rd section

Feeding PointClose

Close

3rd. section

: Feeding Cable from Substation: Section Switch (Closed):Section Switch (Open) = Interconnection Switch

Image of Control Center with DAS

: Distribution Line

Flexible network to demand growthRestored automatically (Distribution


Automation System(DAS))Section switch remote operation capability

Distribution Network in Urban Area

Service Substation

22kV Main/Stand-by Switching System for Urban Area

22kV

22kV Distribution Line

Customer

Customer

Customer

Customer Customer

Customer

Customer

Customer

Step 1O

Step 2O

Steps to Restore

CustomerCustomer Customer

Customer

Line fault !

Main

Standby Load

OutageMain

Standby Load

CB on main line is opened

Outage

Customer Customer CustomerCustomer

Applied in urban area with large customers2 li i d

Step 3Main

Standby Load


2 line service dropsAutomatic switching when one line contingency

After 4 sec, CB on standby line is closed

Equipment for Reliability Improvement

Line Arrester

Overhead Grounding Wire

Line Arrester


Items of Lightning Protection on Overhead Network


LBS with Built-in Arrester


LBS with Built-in Arrester

6.6kV

Inside ofPole mounted Transformer

Discharge Clamp InsulatorDischarge Clamp Insulator

Pole mounted Transformer

Pole Transformer with Built-in ArresterPole Transformer with Built-in Arrester

Copyright© 2009, Tokyo Electric Power Co, Inc. All rights reserved 16Built in Arrester

Non-interruption Work Method

• MV Non-interruption MethodsTemporary switch method- Temporary switch method

- MV by-pass method- Temporary interconnection methodTemporary interconnection method

• LV Non-interruption MethodsTemporary switch method- Temporary switch method

- Temporary transformer method

• Generating Vehicle (Generator) Method


Various Methods for reduction of outage timeI t d ti f Li Li Di t ib ti W kIntroduction of Live Line Distribution Work・ By using “By-Pass Cables” & “By-Pass Switches”, “Planned Outage” is avoided. (Work Area is by-

passed.)• Low voltage (LV) supply is continued by connecting to a neighboring LV system or temporary transformers.

Work Area

Power SourceBy-pass Switch (MV)

Work Area

Line Switch B C bl (MV)Line Switch By-pass Cable (MV)

Copyright© 2009, Tokyo Electric Power Co, Inc. All rights reserved 18By-Pass Cable Temporary Transformer By-Pass Switch

Effect of Non-interruption Work Method

Reduction of “Planned Outage” Duration

80

6669

60

68

5660

70

s

The planned outage time hasBeen decreased drastically byintroducing Non interruption

4843

39

4844

3440

50

Min

utes introducing Non-interruption

work method since 1985.

20

30

M

9

36 6

4 2 2 2 2 2 2 2 2 2 2

0

10

75

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Year

TEPCO’s Power Supply Reliability

140

Forced O utage

SAIDIMinutes/customer/year

91

100

122

100

120

gPlanned O utageTotalIntroduction of Live-Line Work Method

76

9187

60

80

Transformer with built-in Lightning Arrester

20

40

Heavy Snow

122 8 330

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Documents

Loss Reduction Reliability Improvement Hoshi