Version 1.0

Application Guide www.Entec-USA.com

Date: June 2018

Load Break Switch

Three Phase Sectionalizer

With SEL-751 Patent Pending Control Technology

Application Guide Three Phase Sectionalizer

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Subject: Load Break Switch in Sectionalizing Applications

ENTEC Product: Solid Dielectric Load Break Switch with Vacuum Interrupter (LBS)

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 LBS 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.

• LBS 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 LBS 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.

Application Guide Three Phase Sectionalizer

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Solution 1 HIGH FAULT ISOLATION

Branch-1 Fault: 52 Breaker cycles and LBS locks out … Utility Feeder remains energized

Solution 2 PME PROTECTION IN HIGH FAULT ZONE

PME Fault: 52 Breaker cycles, LBS locks out … Utility Feeder remains energized

Application Guide 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 LBS count … PME and Utility Feeder remain energized

Solution 4 INDUSTRIAL VOLTAGE RESTRAINT WITH DOWNSTREAM RECLOSER

Zone A Fault: RX1 cycles to clear fault and LBS locks out … critical SWD continues. Zone B Fault: RX2 cycles to clear fault, Voltage restraint blocks LBS count … RX2 locks out and critical SWD continues.

Application Guide Three Phase Sectionalizer

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Solution 5 PME PROTECTION WITH CUSTOMER RECLOSER

PME Fault: 52 Breaker cycles, LBS locks out … Utility Feeder remains energized

Solution 6 NO COORDINATION REQUIRED

Weak Fault: Fuse won’t coordinate, RX2 cycles, LBS2 locks out … RX2 and Utility Feeder remain energized

Application Guide Three Phase Sectionalizer

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Solution 7 SERIES ZONE ISOLATION

Deep Fault: RX1 cycles, LBS2 locks before LBS1, Zone-2 isolated … Zone-1 and Main Line remain energized

Solution 8 INRUSH RESTRAINT

Fault Cleared Upstream: RX cycles and LBS1 locks out. Inrush Restraint blocks LBS2 … Utility Feeder and LBS2 remain energized

SEL ® is a registered trademark of Schweitzer Engineering Laboratories, Inc. (SEL)