SWEDE
Southwest Electric Distribution Exchange
“The Evolution of Distribution
Switchgear”
April 27, 2012
Presented by: Andy Justice
Reliability Basics
Switching & Manual Sectionalizing
• WHY USE SWITCHES ?
B1
S2
NC
Breaker
NC
Switchgear 1
NC
3-way
Unit
Loop system with sectionalizing
switches
B2
S4
NO
S3
Reliability Basics
Switching & Manual Sectionalizing
• WHY USE SWITCHES ?
B1
S2
NC
Breaker
Locks Out
NC
Switchgear 1
NC
3-way
Unit
NO
B2
S4
S3
Reliability Basics
Switching & Manual Sectionalizing
• WHY USE IT?
B1
S2
OPEN
Breaker
Locks Out
NC
Switchgear 1
NC
Manual Sectionalizing Allows Faster
Restoration of Power to Unfaulted
Portions of the Underground Loop
B2
S4
3-way
Unit
CLOSE
S3
Switchgear Design Overview
Switchgear Design Overview
• Common Interrupting Mediums:
– Oil
– Air
– SF6
– Vacuum
• Insulation Mediums:
– Air Insulated (AIS)
– Oil
– Combination Air and Gas
– Gas (SF6)
– Solid Dielectric
Solid Dielectric Design Principles
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
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•
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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
Solid Dielectric Insulation Background
• 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 Design Principles
Solid Dielectric Desirable Properties
•
•
•
•
•
•
•
•
•
•
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 Design Principles
HIGH DIELECTRIC STRENGTH
Air
11
Oil
3
SF6 Gas
3
0.5
EPDM Rubber
Vacuum
Example:
38kV
150 kV BIL
0.5
Vacuum
= ~1/2”
0
2
4
6
8
10
Dielectric in Inches
12
Solid Dielectric Design Principles
Overall Design Principles
1. SAFETY
2. RELIABILITY
3. OPERATIONAL FLEXIBILITY
4. ENVIRONMENTAL FRIENDLY
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
Switchgear
Applications & Configurations
Switchgear Applications & Configurations
Typical Configurations
Padmount
Subsurface
Riser Pole
Vault
New Modular Design Switchgear
New Modular 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
Interrupters
Load Switches
Standard
Buses Bar
Connection
New Modular Switchgear
Unlimited number of
ways and configurations
New Modular Switchgear
Modular Design Retrofits
New Modular Switchgear
Motor Operator Control
Motor Operator Control
Motor Control System – Motor Installation
Motor Operator Control
Motor Control System Overview
Control and Automation
Advances
Control and Automation Advances
Protection & Automation Controls
Automation
Controls
Stand Alone
Controls
Auto-Transfer
Controls
Switchgear Accessories
Automation Controls
Voltage Sensors Components
Voltage Sensor
Note:
No angle correction (offset) with
Elastimold resistive style Voltage
Sensors making them compatible
with SEL Control Voltage Inputs.
Bushing Extenders for
other phases w/o PT
Cable Connection
200A Source
Input Elbows
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.
Cables From
Control
Note:
Cables From Motor Box
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.
Cables From Control
Voltage Sensor
Cables
Voltage Sensors
Automation Controls
Voltage Sensors View
Automation Controls
Solid Dielectric
Deadfront
Control Power
Transformer
Transformer
7000 -7620/116 127V
(60:1 Ratio)
Summary of Switchgear Selection Considerations
• 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.
Advances in Underground System Automation
SWEDE
Southwest Electric Distribution Exchange
Questions?