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Overhead Distribution Systems

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Improving Distribution Reliability with Reclosers

The Example Distribution Circuit Typical of suburban/rural circuits 10 miles of 3-Phase 13.8 kV Main Feeder 8 single-phase laterals, evenly distributed on the main feeder.

Each lateral 3 miles long, and connected to the main feeder through a fuse

A total of 1800 customers (8 x 225 customers/lateral)

DistributionSubstation 10 miles

115 kV 13.8 kV3 miles

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Basic Radial System

Substation 10 miles

Case 1

SAIFI: 1.6 int/cust/yrSAIDI: 3.3 hrs/yrMAIFI: 8.7 mom/yr

Recloser

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Case 2Substation 5 miles

Recloser

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5 miles

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SAIFI: 1.2 int/cust/yrSAIDI: 2.6 hrs/yrMAIFI: 6.5 mom/yr

Case 2 - with Single-Pole Reclosing

Substation 5 miles

Recloser

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5 miles

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SAIFI: 1.1 int/cust/yrSAIDI: 2.3 hrs/yrMAIFI: 5.4 mom/yr

Single phase

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Loop Configuration with Manual Switch

Substation 1

SAIFI: 1.2 int/cust/yrSAIDI: 2.3 hrs/yrMAIFI: 6.5 mom/yr

5 miles

Case 3

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5 miles

Substation 2

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ManualTie

Switch

Assumptions•Circuit breakers have reclosing capability•Manual Tie Switch requires 1 hour to switch•Reclosers require 1 minute to switch

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Loop Configuration with Manual Switch

Substation 1

SAIFI: 1.1 int/cust/yrSAIDI: 2.0 hrs/yrMAIFI: 5.4 mom/yr

5 miles

Case 3 - With Single-Pole Reclosing

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5 miles

Substation 2

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ManualTie

Switch

Assumptions•Circuit breakers have reclosing capability•Manual Tie Switch requires 1 hour to switch•Reclosers require 1 minute to switch and have single-pole capability

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Automatic Loop Restoration - 3 Reclosers

Substation 1

SAIFI: 1.0 int/cust/yrSAIDI: 2.1 hrs/yrMAIFI: 6.8 mom/yr

5 miles

Case 4

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5 miles

Substation 2

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N.O.Recloser

Assumptions•Circuit breakers have reclosing capability•Reclosers require 1 minute to switch

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N.C.Recloser

N.C.Recloser

N.C. - Normally-ClosedN.O. - Normally-Open

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Automatic Loop Restoration - 3 Reclosers

Substation 1

SAIFI: 0.8 int/cust/yrSAIDI: 1.8 hrs/yrMAIFI: 3.1 mom/yr

5 miles

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5 miles

Substation 2

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N.O.Recloser

Assumptions•Circuit breakers have reclosing capability•Reclosers require 1 minute to switch

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N.C.Recloser

N.C.Recloser

N.C. - Normally-ClosedN.O. - Normally-Open

Case 4 - With Single-Pole Reclosing

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Automatic Loop Restoration - 5 Reclosers

Substation 1

SAIFI: 0.8 int/cust/yrSAIDI: 1.7 hrs/yrMAIFI: 6.5 mom/yr

3.3 miles

Case 5

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3.3 miles

Substation 2

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N.O.Recloser

Assumptions•Circuit breakers have reclosing capability•Reclosers require 1 minute to switch

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N.C.Recloser

N.C.Recloser

N.C. - Normally-ClosedN.O. - Normally-Open

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N.C.Recloser

N.C.Recloser

3.3 miles

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Automatic Loop Restoration - 5 Reclosers

Substation 1

SAIFI: 0.6 int/cust/yrSAIDI: 1.4 hrs/yrMAIFI: 2.7 mom/yr

3.3 miles

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3.3 miles

Substation 2

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N.O.Recloser

Assumptions•Circuit breakers have reclosing capability•Reclosers require 1 minute to switch

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N.C.Recloser

N.C.Recloser

N.C. - Normally-ClosedN.O. - Normally-Open

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N.C.Recloser

N.C.Recloser

3.3 miles

Case 5 - With Single-Pole Reclosing

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Benefits of Single-Pole Reclosing

SAIFI SAIDI MAIFI3-Recloser Automatic Loop Restoration

3-PoleReclosing

1.0 2.1 6.8

Single-PoleReclosing

0.8 1.8 3.1

5-Recloser Automatic Loop Restoration

3-PoleReclosing

0.8 1.7 6.5

Single-PoleReclosing

0.6 1.4 2.7

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Summary of Reclosing Benefits with Single Phase

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Case 1 - Substation reclosing 3 phase only

Case 3 - Loop with Manual Switch

Case 2 - Line Recloser

Case 5 - 5-Recloser Automatic Loop Restoration

Case 4 - 3-Recloser Automatic Loop Restoration

3.3 --- 3.3 ---

2.6 21% 2.3 30%

2.3 30% 2.0 39%

2.1 36% 1.8 45%

1.7 48% 1.4 58%

Hrs/Yr %* Hrs/Yr %*

*% Improvement as compared to Case 1

Single phase

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Predictive Reliability Analysis

Useful for: Looking at system

configuration and design

Placement of protective devices

Impacts of changes in failure rates and restoration times

Analyzing system reliability from a graphical perspective and determining the most cost-effective solutions

ABB Consulting’s Performance AdvantageTM Software