The analysis of the technical problems of the frame circuit breaker product presents the development history, structure and key technology, installation and accessories, common fault analysis and other contents of the frame circuit breaker for the customer in an all-round way.
It is a mechanical switching device used in low-voltage power grid (AC50Hz / 60Hz), with AC rated voltage of ac1140v (DC1500V) and below, which can connect, carry and disconnect the current under normal circuit, and also can connect, carry and disconnect the current under specified abnormal current (such as short circuit) for a certain time.
It belongs to a type of low-voltage circuit breaker, also known as universal circuit breaker, which is used to distribute electric energy and protect overload, undervoltage and short-circuit protection of lines and power supply equipment. Generally, it has an insulating frame structure (fixed type) or a steel frame structure (drawer type), and all parts are installed in the frame.
It has a large capacity (rated current of 200A ~ 8000A), can be installed with multi-functional release and various accessories, and has high breaking capacity, dynamic and thermal stability. Therefore, it is often used in places requiring high breaking capacity and selective protection.
Application system: the frame circuit breaker is close to the transformer side, and the current of the frame circuit breaker is relatively large (800 ~ 6300A).
Product advantages: it can measure more than 150 parameters, assist in analyzing power quality, harmonic analysis, etc; Chinese and English display, display power supply, support three protocols; Multiple locking devices to improve safety.
The first generation of products: in the 1960s, it was designed and developed by completely imitating the products of the former Soviet Union. It only has short-circuit (instantaneous) protection, large structure size, large material consumption (copper), low performance index and incomplete varieties and specifications.
Second generation products: imported foreign advanced technology in the 1970s and 1980s. With overload long delay, short-circuit delay and instantaneous protection, the technical indicators are significantly improved, the volume is reduced, the structure is suitable for the requirements of the complete set of equipment, and the material consumption is still high.
Third generation products: in the mid-1990s, with the improvement of virtual prototype technology, test equipment and technology, arc theory research, and key materials research of low-voltage electrical appliances, new products and technologies constantly emerged.
Fourth generation products: since this century, the design has been optimized on the basis of the third generation products. It is characterized by miniaturization, increased working voltage to ac1140v, ICU = ICs = ICW, higher mechanical and electrical life, multiple wiring modes, multiple accessory functions, more perfect and humanized intelligent (Communication) level, and increased DC products.
Rated shell frame current: INM; Rated current: in; Rated insulation voltage: UI; Rated working voltage: UE; Rated impulse withstand voltage: Uimp; Rated frequency: F
Setting value of long delay overload protection current: IR (TR); Short circuit short delay protection current setting value: ISD (TSD); Setting value of short-circuit instantaneous protection current: II; Setting value of grounding protection current: Ig (TG)
Rated operating short-circuit breaking capacity ICs; Rated limit short-circuit breaking capacity ICU; Rated short-time withstand current ICW; Rated short circuit making capacity (ICM)
Relevant standards for low voltage switchgear and control equipment: GB / T 14048.1-2012, GB / t14048.2-2008, GB / T 14048.5-2008
Relevant standards for special environmental conditions: GB / T 19608.3-2004, GB / t20645-2006, GB / T 20626.3-2006
Other relevant standards: GB / T 2423.4-2008, GB / t4207-2003, GB / T 14092.3-2009
Working steps: before closing the circuit breaker, the operating mechanism shall be operated by the motor or manually to store energy. Press the closing button to close the dynamic and static contacts. Press the opening button to open the circuit breaker.
Fault handling steps: in case of overload or short-circuit fault, the controller judges the magnitude of overload or short-circuit current through the transformer, and sends a pulse signal to the executive unit. The executive unit acts to disconnect the operating mechanism and the contact system. When a short-circuit fault occurs, the moving and stationary contacts are disconnected, and a large number of arcs are generated between the contacts. The arcs are elongated with the opening of the moving contacts. After the arc is generated, the iron grid in the arc extinguishing chamber is magnetized to generate magnetic attraction, which leads the arc to the arc extinguishing chamber. The arc is divided into short arcs by the grid. The cooling effect of the grid on the arc is used to improve the arc resistance and arc voltage and extinguish the arc.
There are two modes of operation: electric and manual
Principle: external energy is provided to compress the spring, and through the cooperation of various levers of the operating mechanism, the movable contact moves to realize opening and closing
Connection position: both the main circuit and the secondary circuit are connected
Test position: the main circuit is disconnected, the secondary circuit is connected, and the necessary action test can be carried out
Separation position: the main circuit and the secondary circuit are disconnected, and the circuit breaker body can be taken out at this position
More comprehensive parameter measurement and sensing capability: it is required to accurately and efficiently transmit the healthy parameters and operating system parameters of the circuit breaker;
It has strong interconnection capability, real-time system operation status and parameter monitoring, early warning and protection;
High reliability control and protection capability: grid protection, adaptive protection, load rejection, synchronous detection and grid connection
Horizontal wiring, vertical wiring, mixed wiring, horizontal extension wiring, vertical extension wiring, mixed extension wiring
Controller, power module (st-iv), secondary wiring terminal, auxiliary switch, interphase separator, undervoltage release, closing / shunt coil, electric operating mechanism, mechanical interlock, door frame, counter, open position lock, relay module
The circuit breaker cannot store energy: the energy storage has been completed, or the manual energy storage is half, the storage capacity is required to be increased, or the control power supply voltage of the electric energy storage device is less than 85% us;
The rocker cannot be inserted into the circuit breaker: the drawer guide rail or the circuit breaker / disconnector body is not fully pushed in, or the padlock handle of the drawer seat is pulled out and locked;
The circuit breaker cannot be disconnected: due to mechanical operating mechanism failure, or the shunt release is damaged, or the control power supply voltage of the shunt release is less than 70% us;
There is no display on the circuit breaker control screen: the circuit breaker controller is not connected to the power supply;