Product Introduction

The truck-type vacuum circuit breaker is a "movable vacuum switch device" specially designed for indoor high-voltage distribution scenarios. Its core feature is integrating the vacuum circuit breaker body onto a retractable "truck," which, combined with a fixed cabinet, achieves three-position switching: "working - testing - maintenance." It combines the environmental benefits of vacuum arc extinguishing with the maintenance convenience of the truck structure. It is mainly used in indoor distribution compartments of 10kV, 20kV, and 35kV medium and high voltage networks (such as KYN series high-voltage switchgear), responsible for line control, short circuit protection, and load switching functions. It is a core device in substations and industrial plant high-voltage distribution rooms.

Core Definition and Key Features

The essence of the truck-type vacuum circuit breaker is the combination of "vacuum arc extinguishing technology + truck-type modular structure." Its core value lies in solving the problems of "safe maintenance" and "flexible operation and maintenance" for indoor high-voltage equipment:

Vacuum arc extinguishing: uses vacuum as the arc extinguishing medium (vacuum degree ≥10⁻⁴Pa), with fast arc extinguishing speed (0.01~0.02 seconds), no oil or SF₆ gas, environmentally friendly and maintenance-free for arc extinguishing medium;

Truck structure: the circuit breaker body is fixed on a truck with rollers, which can be pushed or pulled along the cabinet track to achieve switching among "working position (connecting the high-voltage circuit)," "testing position (disconnecting the main circuit and connecting the control circuit)," and "maintenance position (fully pulled out of the cabinet)." Maintenance can be performed without power shutdown or cabinet removal, with clear disconnection points to ensure personnel safety.

Working Principle

1. Truck Position Switching and Circuit Control

Working position: push the truck along the cabinet track to the innermost side, where the conductive arm closely contacts the cabinet's static contact (main circuit connected), and the control circuit interface is connected; at this time, the operating mechanism can normally open and close the breaker, connecting the circuit breaker to the high-voltage circuit to achieve power transmission.

Testing position: pull the truck out to the middle position, separating the conductive arm from the static contact (main circuit disconnected), but the control circuit remains connected; the operating mechanism can simulate opening and closing actions to test protection devices (such as relay protection) without connecting to the high-voltage power supply.

Maintenance position: the truck is fully pulled out of the cabinet, disconnecting both the main and control circuits; maintenance can be performed on the circuit breaker body (such as the vacuum arc extinguishing chamber and contacts), or the spare truck can be directly replaced for quick power restoration.

2. Vacuum Arc Extinguishing and Fault Protection

Normal opening and closing: when closing, the spring operating mechanism releases the stored spring energy to drive the moving contact in the vacuum arc extinguishing chamber to close with the static contact, connecting the main circuit; when opening, the spring drives the moving contact to quickly separate, instantly extinguishing the arc in the vacuum environment and disconnecting the main circuit.

Fault breaking: when a short circuit or overload occurs on the line (detected by the current transformer), the protection device triggers the operating mechanism to open the breaker, and the vacuum arc extinguishing chamber quickly cuts off the fault current; if the truck is not in the "working position," the position locking device prohibits closing to avoid misoperation.

Application Scenarios

Indoor substations: outgoing line compartments and bus section compartments of 10kV/35kV substations, compatible with armored high-voltage switchgear (KYN series), facilitating daily maintenance and fault handling;

Industrial plants: high-voltage motor feeder circuits in chemical plants and steel mills, requiring frequent commissioning or maintenance; the truck type can reduce downtime;

Commercial / residential buildings: high-voltage distribution rooms in large shopping malls and office buildings, with relatively ample space and high power supply reliability requirements; truck interchangeability allows quick power restoration;

Intelligent distribution systems: electrically driven trucks can cooperate with remote control systems to achieve "remote measurement, remote signaling, and remote control," suitable for unattended intelligent substations.