General The electric sectionalizer has been developed for use on overhead distribution lines to
improve reliability and service continuity. It enhances the protection of the distribution system
in a simple, economical way which is free from maintenance and spares. Statistics indicated
that 70% - 90% of fuse cutout operations are in response to transient faults. The electronic
sectionalizer enables customers to better manage these types of transient faults. It is
designed to substitute a fuse cutout, ensuring effective isolation only in the event of a
sustained fault. It remains unresponsive to transient faults. The sectionalizer is a selfcontained device, designed to be used in a coordinated overcurrent protection scheme with
This sectionalizer uses micro-computer and operating trip mechanism and does not
require external auxiliary supply.And it is designed to withstand the mechanical forces
generated by high fault currents. Its design also caters for the durability needed with repetitive
hook stick closing in harsh outdoor environments.
The electronic sectionalizer incorporates electronic logic and trip circuits which are
controlled and powered by a dual core current transformer mounted on the copper conductive
tube.The current transformer is mounted externally to the conductive tube and encapsulated
in a durable weatherproof epoxy.
The electronic circuit provides the necessary intelligence for counting recloser tripping
operations and provokes the opening of the sectionalizer at the appropriate time. The
electronic circuit is encapsulated with epoxy, within the environmentally sealed conductive
tube. The tube acts as a faraday cage, protecting the electronic circuit from the influence of
Tripping is achieved when a solenoid located in the lower half of the conductive tube is
energized and the trip arm is released enabling the hinged trunnion to collapse.
Working principle The current transformer built in the cutout sectionalizer can detect the current of the main circuit and send the output to the electronic control for digital handling. When a fault occurs, the upstream recloser (or circuit breaker) opens, the circuit loses voltage and the current is lower than 300mA, the electronic controller can remember this opening time as a "count". As it accumulate the presetting number (1 to 4), the sectionalizer will automatic trips within 180ms of fault interruption to isolate fault. Then the upstream recloser (or circuit breaker) closes to restore power supply to the healthy section of the system to limit outage scope and protect the main feeder in service. If the fault is temporary and is cleared before the sectionalizer counter reaches the presetting number, the sectionalizer remains closed and resets to its original state after its reset time expires.
Service conditions a)The ambient air temperature is not above 55ºC or below -40ºC.
b)The average value of the ambient temperature, measured over a period of 24h,does not exceed 25
c)The altitude does not exceed 1000 m (3300ft).
d)The wind speed does not exceed 34 m/s (corresponding to 700 Pa on cylindrical surfaces).
e)The ice coating does not exceed 1mm.
f)The sectionalizer should not apply to those flammable, explosive, corrosive and severe
vibration conditions. As to other service conditions not covered in the manual, please
contact and consult with the manufacturer for detail information.