High voltage circuit breaker refers to the circuit can be connected, disconnected and converted to electrical devices. According to whether there is current in the circuit, the HV circuit breaker is divided into on-load switch and no-load switch. It has high arc extinction performance and can turn off or off the over-voltage and over-current protection in the power system within the prescribed time. For grids with a capacity of 500 kV or more, frequent operation is also required to ensure sufficient flexibility and stability of the system.
Performance characteristics
1、 The circuit breaker has the functions of over-voltage protection and short-circuit protection, and can be used for the protection and control of lines, distribution devices and loads.
2、 The circuit breaker has the function of extinguishing arc, and can quickly and reliably cut off arc within 10 ms.
3、 The circuit breaker has the characteristics of short opening and closing time, and is suitable for places of frequent operation.
4、 The circuit breaker can realize no-load splitting function, which facilitates frequent operation and shortens the time of power cut.
5、 It is basically maintenance-free in the whole life cycle; during the course of switching off, the time of no welding of moving and static contacts and no electromagnetic force on the closing coil of circuit breaker is short, which ensures that the circuit breaker will not burn out.
6、 It has the characteristics of small volume and light weight.
7、 Vacuum arc extinguishing chamber shall be adopted and arc extinguishing control device shall be used instead of manual operation mechanism; arc extinguishing chamber shall be reliable, compact in design and small in installation size.
Principle of operation
When the circuit breaker is energized, the moving contact in the mechanism drives the closing spring through the transmission mechanism to close the circuit breaker. The spring spring makes the breaker close in place.
When the circuit breaker is broken, the moving and static contacts are separated, and the moving contacts in the mechanism are reset first, and then the circuit is cut off by driving the splitting and closing connecting rods under the action of spring force. The position of the moving contact and the static contact is controlled by the spring energy storage mechanism to keep the contact in a certain position.
In addition, there are some accessories such as latching switch, etc., which make the circuit breaker keep a certain position in the course of breaking and closing, so as to prevent misdivision and miscombination.
Structural characteristic
1. The circuit breaker is composed of a shell, a contact group, an arc extinguishing chamber, an arc extinguishing contact, an auxiliary contact and an operating mechanism. Because the contact and interrupter chamber of circuit breaker are separated and combined by electromagnetic force, the contact structure has a great influence on the performance of circuit breaker.
2. Circuit breakers shall be divided into air insulated circuit breakers and vacuum arc interrupters according to different arc interrupting media, and be divided into load switch type and vacuum arc interrupter type according to different use conditions.
3. In order to enable reliable separation and combination between the contact group and the contact group, a position limiting mechanism is arranged in the contact group. The switch position is controlled by a limit handle. Different breakers have different limit mechanisms, but all have corresponding functions.
Classification
1、 According to the mode of operation of circuit breakers, there are two types of breakers: on-load breaker and no-load breaker.
2、 The circuit breakers can be classified into oil circuit breaker, vacuum circuit breaker and sulfur hexafluoride circuit breaker according to the medium of arc extinguishing.
3、 According to the principle of arc extinguishing, there are two kinds of arc extinguishing, one is arc extinguishing without arc, the other is arc extinguishing without arc. Because no arc circuit breaker in the closing process, due to electrical force, it is impossible to achieve complete extinction.
The former uses air as insulating medium and the latter uses sulfur hexafluoride as insulating medium.
5、 According to the classification of protection functions, it can be divided into short circuit fault protection and non-short circuit fault protection.
Post time: Feb-20-2023