What Does One Understand by Reclosers and Their Functionality?

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Do you know that 60 to 95% of the faults on the utility power supply are temporary faults due to lighting and animal contact? So, the utility uses automatic circuit breakers – Reclosers to clear these temporary faults to ensure you don’t have to call a technician in case of a big fault. Generally, when a fault occurs on electric systems, protective devices like fuse and circuit breaker are used to filter or remove the excessive fault current to safeguard your devices from getting damaged. Recloser is also circuit breakers that use their capabilities to reset themselves and safeguard the appliances in case the fault is temporary. 

The electric recloser is automatic switchgear integrated with sensors to protect power lines, electric appliances, and grid systems. These are used throughout the electric distribution system, ranging from single-phase reclosers to three-phase reclosers per the voltage requirements. In this article, we will understand reclosers and their functionality. 

Read on!

Reclosers and their Functionality: Temporary Faults

Most of the troubles and faults on high-voltage lines are temporary due to excessive lighting, falling of tree branches in heavy rain or bird accidents. Based on statistics and observations, the trip-and-reclose function is necessary to safeguard devices. A future reclosure would most likely be successful if the line could be temporarily tripped open because the fault would no longer be present by that time. As a result, the automatic circuit recloser effectively minimises extended distribution system outages caused by transient faults or overcurrent circumstances by offering this trip-and-reclose capability. The following are temporary faults: 

1. Conductors clash with one another due to heavy wind. 
2. Birds and other animals bridge the gap between the high-power line and the ground surface. 
3. Long tree branches make contact between lines. 
4. Flashing over an insulator after lighting surges and conductor slapping.
   

Structure of Reclosers

There are three types of recloser according to the phase – 

1. Single-phase reclosers: These are used to protect single-phase lines or taps of a three-phase feeder. Due to its lightweight, it is directly mounted upon the pole, eliminating the need for an additional mounting frame. 
2. Three-phase reclosers: This type of recloser is used on three-phase circuits to improve system reliability and prevent the phasing of three-phase loads.

3. Triple-single reclosers: Three-single reclosers are controlled electronically with the three modes of operations:
   1. Three-phase trip & three-phase lockout
   2. Single-phase trip & three-phase lockout
   3. Single-phase trip & single-phase lockout

The recloser structure consists of the following parts:

1. Silicone rubber bushing boot
2. Bushing connector
3. Polymer bushing 
4. Current transformers
5. 304 stainless steel tank
6. Magnetic actuator
7. Capacitively coupled voltage sensor
8. Opening spring
9. Auxiliary switches
10. Polycarbonate housing
11. Vacuum interrupter
12. Ceramic breather
13. Mechanical trip ring
14. Insulated drive rod

In the next section, we will understand the main function of a recloser.

Main Functions of Recloser

Reclosers perform simple protective functions and complex algorithms in automation and distribution networks. Following is the function of reclosers:

1. Perform auto-reclosing of the circuit
2. Self-diagnostic in nature
3. Automatic filtering and disconnection from damaged lines
4. Auto reconfiguration of local and remote network
5. It Keeps logs of emergency and operational events in the line.

The functions of reclosers are not limited to the above-given points. All the additional functions are set per the customer’s need and can be determined while ordering reclosers. 

Reclosers trip and close the circuit to ensure reliable and efficient distribution networks. It is a maintenance-free smart device with essential functionality for safeguarding the network from any long-term hazard. We hope this article on reclosers and their functionality helped you. If you need assistance finding the right reclosers, pushbuttons, UPS, speed drivers or more, check out Schneider.

Source:

• www.researchgate.net/publication/337520228_Impact_of_Recloser_on_Protecting_Blind_Areas_of_Distribution_Network_in_the_Presence_of_Distributed_Generation
• www.researchgate.net/figure/Slap-processes-both-dissipate-energy-and-transfer-energy-from-low-to-high-frequency_fig2_241978669