Definition: Auto Recloser is a dielectric automatic circuit recloser (as you also known about a circuit breaker) but it also can make to remote for cutting off power, it is easy to monitor and control. it is fixed each station along the network to protect the power network by circuit breakers or fused which will turn off power in the event of a short circuit, a tree branch blow off during a windstorm and lands on the line may cause a short circuit, it use over load of power might cause to trip or earth fault that cause to power off. it can fix the adjustable time delays if the fault is appear.

 DSA/SCADA Compatibility: When auto recloser used with a compatible Distribution System Automation (DSA) or SCADA system, some kinds of automatic circuit reclosers support remote control and monitoring to provide the following advantages:

• Information on recloser status and fault current values transmitted to system control allows fast location of the faulted line section, reducing the traveling time of line crews.

• This same information allows informed remote or automatic switching of lines, which reduces the area affected and quickly restores supply. Quality of supply is improved as a result.

• Reclosers can be configured and managed from system control, without technicians having to visit each individual recloser in the field to change configuration settings. This allows a reduction in staffing and improved system integrity.

Pole Mounting Detail

The installation should be connected from the power line to X-side terminal on the top for incoming power line and power line will connect to I-side terminal for outgoing power line to protect the power network. the surge arrester should be fixed including on the power line, earth must connect to ground, the control system need the power 220V or 110V to supply, so that we need to install one more transformer and connect the power from that transformer.

I would like to make an example on the Automatic Circuit Recloser of the U-Series of the NU-LEC Industries and the others are like similar which including more detail.

1-     Recloser Overview and Operation

The U-Series automatic circuit recloser uses vacuum interrupters, contained in epoxy bushings, eliminating the need for insulants like oil and gas. The mechanism is enclosed in a 316 grade stainless steel tank with a stainless steel lid. The cyclo-aliphatic epoxy resin casting is bolted onto the lid.

Monitoring and control of the recloser is performed by the field proven Pole Top Control and Communications cubicle (PTCC), of which many thousand are in service worldwide. The PTCC houses the Operator Control Panel and microelectronics that provide the protection functions. It is normally located lower down the pole for ease of access and is connected to the circuit breaker by a detachable control cable. The circuit breaker and PTCC together form a remotely controlled and monitored automatic circuit recloser.

The recloser is operated by a magnetic actuator which produces a positive opening and closing action. Switching occurs when a controlled pulse is sent through the open/close actuator from a storage capacitor in the PTCC. When closed, the switch is latched magnetically. Spring loaded pushrods provide contact loading on the interrupters.

A Current Transformer (CT) and a Capacitive Voltage Transformer (CVT) are moulded in the CT-housing. These are monitored by the PTCC for remote monitoring and display. The PTCC requires an auxiliary AC supply. A control cable connects the PTCC to the bottom of the circuit breaker through a covered plug/socket sealing arrangement on both the PTCC and the tank.

The recloser is supplied with copper stems or optional cable clamp connectors. Mounting brackets for lightning arresters are optionally available. The recloser contact position is shown by a large, clearly visible external pointer.

A hookstick can be used to engage the manual trip ring to trip and lockout the recloser from the ground. The mechanical trip ring has two positions. In the “up” position normal operation takes place. In the “down” position the recloser is tripped and both mechanically and electronically locked open.

The Pole Top Control Cubicle (PTCC) interfaces to the recloser via the control cable and connects to the Switch Control Entry Module (SCEM) in the base of the tank. The SCEM uses EEPROM memory to store all relevant calibration data, ratings and number of operations conducted. The SCEM also provides the first stage of electrical isolation and shorting electronics to short the CTs and CVTs in the event the control cable is disconnected while current is flowing through the recloser.

2- Communications Cubicle Overview

The advanced protection, data logging and communications abilities of the U-Series automatic circuit recloser are made possible by the technology housed in the control and communications cubicle. It has been designed especially for outdoor, pole mounted operation and is normally mounted low on the pole for ease of access by maintenance personnel.

The cubicle is insulated and designed to minimize any temperature rise resulting from solar heating. An internal equipment panel is used to mount all the equipment, including the batteries, storage capacitors, mains transformer, low voltage circuit breakers, Control And Protection Module (CAPM), Operator Control Panel and radio or modem. These components are carefully located so that the heat generating parts are at the top, while the battery is at the bottom to keep it cool. In this way battery life in excess of 5 years can be achieved. All weather access is provided to the Operator Control Panel through a lockable door on the front of the control cubicle. Vents are screened against vermin entry

and the door is sealed against the outer with a rubber extrusion. All electronic parts are well protected from entry of moisture and condensation ensuring a long lifetime. Three models of control and communications cubicle are available, Tropical, Moderate and Temperate. The Tropical version is well ventilated and is suitable for climates where the ambient temperature can reach 50°C and only occasionally goes below 0°C, with a lower limit of -10°C. The Moderate version has reduced ventilation and is used where temperatures rarely go above 40°C and occasionally go below -5°C, with a lower limit of -15°C. The Temperate model has a heater installed, making it suitable for climates where the temperature rarely goes above 40°C but can fall as low as -30°C. All three cubicles are fitted with the same electronics and incorporate the functions of an over current protection relay, a sensitive earth fault relay, a reclose relay, and a remote terminal unit. Additionally, the electronics measure line current, voltage, real and reactive power, fault currents, and stores these for transmission or off-line analysis. A unique feature of the Nu-Lec Industries automatic circuit recloser is the built-in microprocessor controlled power supply. This provides uninterrupted operation of not only the circuit breaker and protection relay, but also the communications radio or modem. No other power supplies are required for connection into your SCADA or Distribution Automation System. Due to careful design the efficiency of all parts is extremely high, allowing a battery hold up time of five days after auxiliary supply failure (from fully charged battery, excluding telemetry radio or modem usage). The architecture used has the

advantage that the circuit breaker operation is independent of the high voltage supply, relying on a set of batteries charged by the auxiliary supply.

Due to sophisticated power supply management techniques, a circuit breaker operation is always guaranteed when attempted and alarms are raised over the telemetry when auxiliary power is lost. A communications radio or special modem can be mounted within the control and communications cubicle. A V23 FSK modem is included as standard equipment.

Specifications

15.5 kV

27 kV

Description / Ratings

 

 

Rated Maximum Voltage . . . . . ……………………..

15.5kV

27kV

Rated Continuous Current . . . . . . . . ……………..

630A

630A

Fault Make Capacity (RMS) . . . . ……………………

12.5kA

12.5kA

Fault Make Capacity (Peak) . . . . . …………………

32.5kA

32.5kA

Fault Break Capacity . . . . . ………………………….

12.5kA

12.5kA

Power Operating Time (Close/Open) . ……………..

0.1 / 0.05s

0.1 / 0.05s

Mechanical Operations . . . . . . ………………………

10000

10000

Rated Full Load Operations . . . . . …………………..

10000

10000

Short Time Current (3 seconds) . . . . . …………….

12.5kA

12.5kA

Breaking Capacity

 

 

Mainly Active (0.7pf) . . . . . . . ……………………….

630A

630A

Cable Charging . . . . . . . ……………………………..

25A

25A

Line Charging . . . . ……………………………………..

5A

5A

Transformer Magnetizing Current . . ………………..

22A

22A

Environmental

 

 

Ambient Temperature (1) . . . . . ………………………

-30 to 50°C

-30 to 50°C

Radiation (Max) . . …………………………………….

1.1kW/m²

1.1kW/m²

Humidity . . . . . . ……………………………………….

0 to 100%

0 to 100%

Altitude (Max). . . . . …………………………………..

3000mm

3000mm

Standard . . . . . . . . …………………………………..

W=1160mm D=960mm H=1020mm