Installation Manual for Chengdu Outdoor High Voltage 35KV Vacuum Circuit Breaker ZW7

1 OverviewInstallation Manual for Chengdu Outdoor High Voltage 35KV Vacuum Circuit Breaker ZW7

The ZW7-40.5 outdoor high-voltage vacuum circuit breaker adopts a uniquely designed split pole and a highly reliable operating mechanism. This device is mainly used in medium voltage overhead power grids for the purpose of dividing and combining load currents, overload currents, and short-circuit currents.

U has extremely high reliability

U is completely maintenance free throughout its entire lifespan

U has high mechanical and electrical lifespan

The whole machine has a small volume, light weight, and is easy to install

1.1 Usage conditions

Environmental temperature: not higher than+40 ℃, not lower than -15 ℃

Altitude: not exceeding 2000 meters;

Wind speed not exceeding 34m/s;

External vibrations or ground movements from switchgear and control equipment can be ignored;

Pollution level: Level IV;

Storage temperature: -40 ℃ to+85 ℃.

2 Circuit Breaker Structure

The ZW7-40.5 outdoor high-voltage vacuum circuit breaker is mainly composed of integrated pole, current transformer, operating mechanism, and box body. This model of circuit breaker is designed for miniaturization, with a high-quality steel casing. Current transformers can be selected according to user needs.

ZW7-40.5 outdoor high-voltage vacuum circuit breaker and its matching intelligent control combination. The switch can be opened and closed locally, or remotely controlled through a communication interface. Other information of the circuit breaker can also be transmitted to the control center, and communication channels can be selected from cables, optical fibers, GPRS/CDMA, GSM, etc.

Working principle of 3 circuit breakersInstallation Manual for Chengdu Outdoor High Voltage 35KV Vacuum Circuit Breaker ZW7

3.1 Arc extinguishing principle:The ZW7-40.5 outdoor high-voltage vacuum circuit breaker adopts a vacuum arc extinguishing chamber, which uses vacuum as the arc extinguishing and insulation medium, and has a very high vacuum degree. When the moving and stationary contacts are charged and disconnected under the action of the operating mechanism, a vacuum arc will be generated between the contacts. At the same time, due to the special structure of the contacts, an appropriate longitudinal magnetic field will also be generated in the gap between the contacts, which promotes the vacuum arc to maintain a diffusion type and evenly distributes the arc on the surface of the contacts to burn, maintaining a low arc voltage. At the natural zero crossing of the current, residual ions, electrons, and metal vapor can recombine or condense on the surface of the contacts and the shielding cover in microseconds. The dielectric insulation strength of the arc extinguishing chamber fracture is quickly restored, and the arc is extinguished to achieve the purpose of disconnection. Due to the use of longitudinal magnetic field control for vacuum arc, vacuum circuit breakers have strong and stable breaking current capability.

3.2 Electric energy storage:The electric motor applies the output torque to the small gear of the mechanism, which is transmitted to the large sprocket on the main shaft, thereby driving the crank arm to rotate and storing energy in the closing spring. When the screw on the crank arm presses down the travel switch, the power supply to the motor is cut off and the spring energy storage is completed.

3.3 Manual energy storage:The output shaft of the rotating mechanism transmits rotational torque to the fully meshed large gear through the small gear on the output shaft, thereby driving the crank arm to rotate and storing energy in the closing spring.

3.4 Operation of closing electromagnet:After receiving the closing signal, the moving iron core of the closing electromagnet moves upward, pushing the closing release rod to move upward, causing the closing half shaft to rotate counterclockwise. Release the constraint on the closing stopper, and at the same time, the closing stopper rotates counterclockwise under the pressure of the roller, releasing the energy storage maintenance. The cam located on the main shaft generates an impact force due to the contraction force of the closing spring, which collides with the rocker arm on the manual energy storage shaft (i.e. output shaft), and is transmitted to the switch through the connecting rod to complete the closing operation.

3.5 Manual operation:When the fork installed on the closing half shaft rotates counterclockwise, it drives the closing half shaft to rotate counterclockwise. Thus producing the same effect as the operation of the closing electromagnet.

3.6 Reclosing operation:After releasing the energy of the energy storage spring, the mechanism completes the closing operation. In the closed state, the mechanism performs energy storage operation again. After completing the energy storage operation, the mechanism is in the closed and stored state. Once the correct signal is received in this state, the mechanism can achieve an automatic reclosing operation.

3.7 Operation of opening electromagnet:After receiving the opening signal, the moving iron core of the opening electromagnet moves upward, pushing the opening release rod to move upward, causing the opening half shaft to rotate counterclockwise. Release the constraint on the switch breaker. At the same time, the opening stopper rotates counterclockwise under the pressure of the roller, and the rocker arm rotates counterclockwise due to the pushing force of the opening spring inside the switch, thus completing the opening operation.

3.8 Manual operation:When the fork installed on the opening half shaft rotates counterclockwise, it drives the opening half shaft to rotate counterclockwise, thereby producing the same effect as the operation of the opening electromagnet.

3.9 Overcurrent trip operation:When the overcurrent coil in the overcurrent release passes through the specified tripping current, the electromagnet acts and the push rod pushes the tripping rod. Rotate the half shaft of the circuit breaker counterclockwise to release the constraint on the circuit breaker and produce the same effect as the operation of the opening electromagnet, completing the overcurrent tripping operation of the circuit breaker.