Power Capacitor Switching Device

General Description
The JKCN series power capacitor switching device is mainly used for switching on/off low voltage power capacitor in the reactive power compensation system with rated voltage of AC 220V or 380V and frequency of 50Hz-60Hz. It is characterized by low loss, high stability, high reliability, no noise, and no switching surge current.

Function Features
The JKCN power capacitor switching device consists of three independent combination switches. It is suitable for switching on/off low voltage reactive power compensating capacitor bank. The basic working theory of combination switch is as follows. The thyristor switch is connected in parallel with the magnetic latching relay. This enables the switching device to have the advantage of thyristor zero switching at the moment of switching on/off and consume no power during conduction period.

1. Zero Switching
By connecting the thyristor switch and magnetic latching relay in parallel, the combination switch is able to realize capacitor switching on at the moment of zero voltage and capacitor switching off at the moment of zero current. In the instant of switching on and off, the combination switch produces no surge current, just like the thyristor switch. During the period of normal conduction, our product consumes no energy, like the physical switch. Operating methods are as follows.
During switching on, firstly close the thyristor switch at the moment of zero voltage. After stabilization, close the magnetic latching relay; during switching off, break the magnetic positioned relay at first and open the thyristor switch at the moment of zero current .

2. Perfect Protection
A microcontroller is adopted for controlling switching on and off. The running state of the thyristor switch, latching relay, power supply, and loads are monitored, ensuring perfect protection functions.
a. Voltage fault phase loss protection
When the system voltage supplied with phase loss, the switching device can not be closed.
b. Power supply phase loss protection
When the working power source supply voltage with phase loss, the switching device can not be closed.
c. Self-diagnostic fault protection
The working status of the thyristor switch and magnetic latching relay are monitored automatically. Once fault occurs, the switch can not be closed or it automatically switch off the capacitor.
d. Power failure protection
When closed but power cut suddenly, the switch will automatically trip.

3. No Harmonic
During switching on, the thyristor switch is firstly closed. After a delay, the magnetic latching relay is closed. No harmonics will be produced when the relay works.

4. Low Power Consumption
Due to the adoption of the magnetic latching relay, this switching device consumes energy only at the instant of switching on/off. Furthermore, since the contact resistance of the latching relay is small, little heat will be produced. So no heat sink or fan is needed, thus reducing cost. In addition, burning of the thyristor switch is completely avoided and no damage will be caused to surrounding electric equipment.

5. High Reliability
The input signal is isolated from the switch photoelectrically, ensuring strong anti-interference and high safety and reliability.

Related Names
Power Factor Improvement Device | Power System Controller | High Power Switch