VTZ-12 Series Indoor Phase-selective Switching Intelligent Vacuum Circuit Breaker

 VTZ-12 indoor phase-selective switching intelligent vacuum circuit breaker (Tongzhong Electric's exclusive model) is designed for indoor switchgear with a rated voltage of 12kV and AC 50/60Hz. It utilizes a permanent magnet operating mechanism and is suitable for specialized applications in various industrial and mining enterprises and power grids. The trolley unit can be used directly with the KYN28A-12 switchgear, directly replacing conventional three-phase integrated vacuum circuit breakers in existing switchgear.

This intelligent vacuum circuit breaker features a permanent magnet mechanism, a permanent magnet mechanism controller, and an intelligent processor. Three controllers, working with three independent permanent magnet mechanisms, enable phase-selective switching of three-phase systems. Furthermore, the intelligent processor features adaptive functionality, using feedback from voltage and current signals for synchronous calculations and issuing commands to enable the circuit breaker to switch on and off at any phase, meeting diverse application requirements.

VTZ-12 indoor phase-selective switching intelligent vacuum circuit breaker has many applications :

In power systems, phase-selective switching (also known as synchronous switching or phase-controlled switching) of mechanical switches involves precisely controlling the switching moment to close or open the switch at a specific phase angle (such as the voltage or current zero crossing) of the voltage or current waveform. This technology is primarily used to reduce transient shock during switching operations, thereby improving system stability and equipment life. The following are its typical application scenarios and advantages:

(1) Capacitor bank switching: Capacitor banks need to be frequently switched in reactive power compensation devices. Closing at the voltage zero point avoids inrush current (up to 10-20 times the rated current); disconnecting at the current zero point prevents arc reignition and overvoltage.

(2) Transformer excitation inrush current suppression: When the transformer is switched on at no-load, excitation inrush current is easily generated. Closing at the voltage peak moment (the initial value of the magnetic flux is the maximum) can significantly reduce the inrush current and reduce the impact on the power grid.

(3) Motor control: Starting and stopping large-capacity motors. Starting at the voltage zero point reduces the starting current impact; disconnecting at the current zero point reduces the arc energy and protects the mechanical switch contacts.

The voltage difference between each phase of the three-phase system is 120°. The phase selection closing target is that each phase switch is closed at a specific phase angle of the voltage at both ends of its own break, and the phase selection opening target is that each phase switch is disconnected at the zero point of its own phase current. The following takes the switching capacitor as an example. The capacitor adopts a star connection method and the neutral point is not grounded. When switching on capacitors, the switches should be closed at the voltage zero crossing point. The three-phase closing order is B->A->C, and the opening order is A->C->B. When closing, phase B is closed first. At this point, the system does not form a loop and there is no current flowing, so no phase selection is required when switching on phase B. Next, phase A is switched on. The switch on phase A should be closed at the zero crossing point of the voltage on line AB. After both phases A and B are switched on, the voltage across phase C will shift in phase. At this point, the voltage across phase C will be 90° out of phase with the previous voltage on line AB. Therefore, phase C should be switched on 10*n+5ms after phase A is switched on, where n is a positive integer.

Application place 

VTZ-12 series phase-selective switching intelligent circuit breaker is a customized product. The secondary wiring method needs to be determined based on the user's operating environment.

Shaanxi West Power Tongzhong Electrical Co., Ltd. is a leading manufacturer with over 20 years of experience, specializing in high quality 7 to 40.5kV vacuum circuit breakers, switchgears, and a wide range of electrical products. Our advanced manufacturing process ensures reliable, durable solutions, especially our VTZ series vacuum circuit breakers, which are maintenance-free for up to 20 years. With a team of expert technicians, we excel in R&D, manufacturing, and after-sales service for both high and low voltage equipment, delivering excellence at every stage.

Introduction and Location
Founded in 2014, Shaanxi West Power Tongzhong Electrical Co., Ltd. is a leading innovator in the electrical industry with over 20 years of industry experience. Strategically located at No. 1 East Gaoxin Avenue in the High-Tech Development Zone of Baoji City, Shaanxi Province, our prime location offers excellent connectivity through expressways and high-speed railways. This advantageous location allows us to efficiently serve both domestic and international markets, ensuring fast response times and seamless logistics.

Our Mission and Vision
Since our founding, we have been driven by a mission to revolutionize power transmission and distribution systems. Our vision is to expand our international market share and establish our VTZ brand as a symbol of quality and innovation in the electrical industry. We are committed to becoming a global leader, known for our dedication to advancing technology, ensuring quality, and prioritizing customer satisfaction.

 

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