April 27, 2012Presented by: Andy Justice

SWEDE Southwest Electric Distribution Exchange

“The Evolution of Distribution Switchgear”

B1

Switchgear 1

NC NCS2

NC

NO

S3S4B2

Breaker

• WHY USE SWITCHES ?

Loop system with sectionalizing switches

3-wayUnit

Switching & Manual Sectionalizing

Reliability Basics

3-wayUnit

B1

Switchgear 1

NC NCS2

NC

NO

S3S4B2

BreakerLocks Out

Switching & Manual Sectionalizing• WHY USE SWITCHES ?

Reliability Basics

• WHY USE IT?

3-wayUnit

B1

Switchgear 1

OPEN NCS2

NC

CLOSE

S3S4B2

Manual Sectionalizing Allows Faster Restoration of Power to Unfaulted Portions of the Underground Loop

Switching & Manual Sectionalizing

BreakerLocks Out

Reliability Basics

• Common Interrupting Mediums:– Oil– Air– SF6– Vacuum

• Insulation Mediums:– Air Insulated (AIS)– Oil– Combination Air and Gas– Gas (SF6)– Solid Dielectric

Switchgear Design Overview

Switchgear Design Overview

Air Switchgear Concerns

• Outages due to Corrosion, Animals, Dirt, Flashovers, Lack of Maintenance and Moisture

• Longer outage times to replace and upgrade

• Larger Equipment Footprint

Solid Dielectric Design Principles

Oil Switchgear Concerns

• Oil is vaporized and gas extinguishes arc

• Old technology – Outages due to lack of maintenance and loss of insulation

• Environmental issue of Oil Spill

• Safety Concern/Risk associated with Fires

Solid Dielectric Design Principles

SF6 Switchgear Concerns

• Outages due to loss of insulation, low gas pressure levels, low temperature and lack of maintenance.

• Environmental concerns – green house gases

• Difficult to fit into confined spaces

• Gas Disposal Issues

Solid Dielectric Design Principles

Air, SF6 and Oil Switchgear Summary

• Larger Footprints• Sensitive to Environment and Contaminates• Frequent maintenance/monitoring Required• Higher Risk of Failure• Higher Risk of Fire• Higher Costs for Maintenance Staff & Switching• Longer Outages to Repair/Replace

Solid Dielectric Design Principles

• Desire for alternate mediums after WWII due to unavailability of Porcelain and Glass Insulators

• Epoxy Resin Current & Voltage Transformers were introduced in Europe in the 1947

• In 1952 Polymer insulation casting was introduced in USA• GE began a material study in 1954 & from there insulator trials began• Ethylene-Propylene introduced in 1962• In 1965, Cycloaliphatic Epoxy was applied in outdoor applications • In 1966, first few air-blast breaker insulators were made out of

fiberglass reinforced Epoxy• Since the 1960’s, EPDM rubber experienced rapid growth• In 1996 Elastimold introduced the first Solid Dielectric Switchgear

Design

Solid Dielectric Insulation Background

Solid Dielectric Design Principles

• Dielectric strength• Mechanical strength• Impact strength• Light weight• Thermal shock resistance• Tracking resistance• Inertness to contamination & weathering• Consistent and easy manufacturing processing• Economic• Reliability

Solid Dielectric Desirable Properties

Solid Dielectric Design Principles

0.5

3

3

11

0 2 4 6 8 10 12

Vacuum

EPDM Rubber

SF6 Gas

Oil

Air

Vacuum = ~1/2”Dielectric in Inches

HIGH DIELECTRIC STRENGTH

Example:38kV

150 kV BIL

0.5

0.5

3

3

11

0 2 4 6 8 10 12

Vacuum

EPDM Rubber

SF6 Gas

Oil

Air

Solid Dielectric Design Principles

1. SAFETY

2. RELIABILITY

3. OPERATIONAL FLEXIBILITY

4. ENVIRONMENTAL FRIENDLY

Overall Design Principles

Solid Dielectric Design Principles

1. Increased Safety– Dead-Front Construction – Insulated and shielded product with not

high-voltage exposed components– Not dependent on oil, gases or air for proper isolation from high

voltage

2. Reliability– Utilizes Maintenance-Free Vacuum and EPDM Molded Insulation

Technology which has over 50 years of field proven performance– Fewer Outages and significantly Lower Outage Durations– All Switchgear Components are Sealed and Fully Submersible

Solid Dielectric Design Principles

3. Operational Flexibility – Compact and Lightweight Design allows installation in tight spaces– Modular Design allows combining with other devices

• Interchangeable, Upgradeable, Customer Configurable• Less Inventory (Stock Common Components)

– Non-Position Sensitive so it can be installed anywhere & in any orientation

– Overall Lower Cost of Ownership

4. Environmentally Friendly– No oils or gases to monitor, maintain or dispose of – EPDM Rubber is a GREEN solution; Contains no greenhouse

gases, such as SF6

Solid Dielectric Design Principles

Switchgear Applications & Configurations

Typical Configurations

Padmount Subsurface

Riser Pole Vault

Switchgear Applications & Configurations

New Modular Design Switchgear

• New Modular Design Switchgear will provide solutions to:– Installations with confined vault spaces– Modular Design Retrofits– Ease of installation– Unlimited number of ways– Configuration flexibility– Upgradable– Provide Overall installation cost savings

New Modular Switchgear

• Up to 35 kV rating for both Load-Break Switches and Fault Interrupting Devices

New Modular Switchgear

Interrupters Load Switches

Standard Buses Bar Connection

New Modular Switchgear

Unlimited number of ways and configurations

Modular Design Retrofits

New Modular Switchgear

New Modular Switchgear

Motor Operator Control

Motor Control System – Motor Installation

Motor Operator Control

Motor Control System Overview

Motor Operator Control

Control and Automation Advances

Stand Alone Controls

Automation Controls

Auto-Transfer Controls

Control and Automation Advances

Protection & Automation Controls

Switchgear Accessories

Voltage Sensors Components

200A Source Input ElbowsBushing Extenders for

other phases w/o PT Cable Connection

Voltage Sensor

Note:No angle correction (offset) with Elastimold resistive style Voltage Sensors making them compatible with SEL Control Voltage Inputs.

Automation Controls

Start Up Connections:1. Insert the Voltage Sensors into

the 600A Elbow and tighten using a 600ATM Assembly Tool (See IS-1127).

2. Connect all the Voltage Sensors to the corresponding marked cables from the Switch Motor Box.

Note: Connections are based on Motor

Operator being supplied as a system. If Motor Operators are not packaged as a system, the Voltage Sensors will plug directly into the Control.

Voltage Sensors

Voltage Sensor Cables

Cables From Control

Cables From Control

Cables From Motor Box

Automation Controls

Voltage Sensors View

Automation Controls

Solid Dielectric Deadfront

Control Power Transformer

Transformer 7000 -7620/116 127V

(60:1 Ratio)

Automation Controls

• Select State-of-the-art technology and suppliers with strong commitment to customer support.

• Utilize Solid Dielectric insulation and vacuum switching/ interruption which translate into small footprint and maintenance free Equipment.

• Specify that the Switchgear be fully submersible and feature deadfront construction for increased safety of operation.

• Supplier needs to provide a wide range of configurations that fits multiple application needs and contributes to improve the reliability and operating performance of underground distribution systems.

• Look for Modular Platforms and Designs in order to Maximum Flexibility and allow Future Expansion.

Summary of Switchgear Selection Considerations

Questions?

Advances in Underground System Automation

SWEDE Southwest Electric Distribution Exchange