Entec Load Break Switch Benutzerhandbuch
Version 1.0
Application Guide
www.Entec-USA.com
Date: June 2018
Load Break Switch
Three Phase S
ectionalizer
With SEL-751 Patent Pending Control Technology
Application Guide
Three Phase Sectionalizer
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Sub ect: Load Break Switch in Sectionalizing Applications
ENTEC Product: Solid Dielectric Load reak Switch with Vacuum Interrupter (L S)
Sectionalizer Description Sectionalizers are used in tandem with upstream protective
devices such as reclosing breakers or reclosers to automatically isolate faulted sections of
distribution lines. The sectionalizer senses current above a pickup value and counts when the
upstream device de-energizes the circuit. After meeting a predetermined count, and while the
circuit is de-energized, the sectionalizer opens. This allows for a section to be isolated without
locking out the entire circuit by the upstream device. Sectionalizers do not interrupt fault
current, hence they are coordinated with an upstream recloser or breaker.
Three Phase Sectionalizer Advantages:
• A sectionalizer easily coordinates with any protective device; they do not require time-
current curves. This is an advantage in high fault zones or deeper within a feeder
behind multiple curves having tight coordination.
• Single phase damage is avoided with a three phase sectionalizer making it superior
versus fuses. When operated, all three phases simultaneously open.
• Without a time-current curve, sectionalizers placed between reclosers and fuses provide
additional points of separation for strategic isolation.
• Using state-of-the-art voltage restraint, the L S sectionalizer will function between
reclosers. Utilities can now protect PME’s without introducing another time-current curve
even with a recloser on the customer side.
• L S is equipped with a Schweitzer relay (SEL-751) and patent pending technology for
dependable, smart sectionalizing control. SEL-751 includes metering and superb
analysis tools familiar to SEL customers.
• Sectionalizers cost significantly less than reclosers.
• The L S can be switched manually or automatically and supports Scada.
Solution to Issue:
Reclosers cycle repeatedly for permanent faults eventually locking-out an entire distribution
system to isolate faults. These events often impact a significant number of customers and
result in extensive outages. Interruptions and downtime negatively impact reliability metrics
such as SAIFI, SAIDI, CAIFI and CAIDI.
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Three Phase Sectionalizer
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Solution 1
HIGH FAULT ISOLATION
ranch-1 Fault: 52 reaker cycles and L S locks out … Utility Feeder remains energized
Solution 2
PME PROTECTION IN HIGH FAULT ZONE
PME Fault: 52 reaker cycles, L S locks out … Utility Feeder remains energized
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Three Phase Sectionalizer
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Solution 3
UTILITY VOLTAGE RESTRAINT WITH DOWNSTREAM RECLOSER
Customer Fault: Customer recloser cycles to clear fault and locks out, Voltage Restraint blocks
L S count … PME and Utility Feeder remain energized
Solution 4 INDUSTRIAL VOLTAGE RESTRAINT WITH DOWNSTREAM RECLOSER
Zone A Fault: RX1 cycles to clear fault and L S locks out … critical SWD continues.
Zone Fault: RX2 cycles to clear fault, Voltage restraint blocks L S count … RX2 locks out
and critical SWD continues.
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Three Phase Sectionalizer
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Solution 5 PME PROTECTION WITH CUSTOMER RECLOSER
PME Fault: 52 reaker cycles, L S locks out … Utility Feeder remains energized
Solution 6
NO COORDINATION REQUIRED
Weak Fault: Fuse won’t coordinate, RX2 cycles, L S2 locks out … RX2 and Utility Feeder
remain energized
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Three Phase Sectionalizer
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Solution 7
SERIES ZONE ISOLATION
Deep Fault: RX1 cycles, L S2 locks before L S1, Zone-2 isolated … Zone-1 and Main Line
remain energized
Solution 8
INRUSH RESTRAINT
Fault Cleared Upstream: RX cycles and L S1 locks out. Inrush Restraint blocks L S2 … Utility
Feeder and L S2 remain energized
SEL
®
is a registered trademark of Schweitzer Engineering Laboratories, Inc. (SEL)
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