Selection of pneumatic circuit breaker and self energy circuit breaker
it is certain that the pneumatic SF6 circuit breaker, which is still in mass production and use at present, can meet the needs of China's high-voltage and ultra-high voltage power systems in terms of various breaking performance and electrical life, breaking capacity and single break voltage level. The biggest disadvantage of the compressed SF6 circuit breaker is the leakage of the high-power hydraulic mechanism or pneumatic mechanism
the hydraulic mechanism has decades of production history and use experience. It is precisely because it has been used for too long, the number of uses is too large, and the leakage phenomenon seems to be too many. The user department hopes to have a pure mechanical operating mechanism with relatively simple and intuitive structure, no liquid and gas, no pressure and seal, and no pressure monitoring and locking to replace the hydraulic mechanism, To reduce a lot of maintenance work caused by leakage. The restart of spring operating mechanism and the emergence of self energy SF6 circuit breaker meet the needs of the majority of operating departments
customers often think that the price of domestic experimental machines should be low.
the biggest feature of self powered SF6 circuit breaker is that it greatly reduces the operating power. The biggest advantage is that it adopts a pure mechanical spring operating mechanism, which does not have the problem of oil or gas leakage and sealing. However, we should also note that the self energy SF6 circuit breaker will also affect some of its breaking performance and technical indicators due to the reduced operating power, thus limiting its use. At present, the self energy SF6 circuit breaker produced mainly depends on the energy of the short-circuit arc itself to increase the pressure of SF6 gas in the arc extinguishing chamber to achieve the arc extinguishing pressure. Therefore, it is bound to increase the arc burning time, increase the burning loss of nozzles and contacts, and reduce the initial recovery rate of dielectric strength, so as to make the short-circuit breaking capacity, electrical life times, near-field fault breaking capacity The withstand voltage level of the fracture is not up to the level of the currently produced pneumatic SF6 circuit breaker. The single fracture voltage can only reach 220kV level, and the short-circuit breaking capacity is only 40ka. Moreover, since the structure of the arc extinguishing chamber of the self energy SF6 circuit breaker is more complex, the number of components is increased, and the reliable cooperation is required when breaking different currents, which not only increases the manufacturing difficulty, but also may have an adverse impact on the electrical reliability. The structure is simple and intuitive, but its operation reliability is still difficult to say that it is higher than the hydraulic mechanism. Otherwise, friendship tips are widely used in the era of low oil circuit breaker: if there is something unclear, it is not the hydraulic mechanism. The spring mechanism overcomes the leakage problem of the hydraulic mechanism, but more mechanical faults may occur, such as mechanical deformation, damage, stagnation and failure of the opening and closing latch, and the manufacturing quality of the spring itself is also difficult to control, especially the coil spring and torsion spring, so spiral springs are mostly used at present. The self energy SF6 circuit breaker equipped with spring mechanism is still in the process of development, and its electrical performance still needs to be continuously improved, so it is difficult to replace the compressed air SF6 circuit breaker in the short term. Source: power transmission and distribution equipment
the guidance on energy efficiency design of affordable housing buildings in Shanghai (hereinafter referred to as the "guidance") of the self energy SF6 circuit breaker equipped with spring operating mechanism appeared, which solved the problems of the operation Department caused by the leakage of hydraulic mechanism for a long time. Therefore, it is understandable that many operation departments have or are considering the selection of self energy SF6 circuit breakers. However, the current self energy SF6 circuit breaker is still in the process of development. While it shows its advantages, many new problems still need to be solved, and it is also an indisputable fact that it lacks operating experience. Therefore, the operation department should pay full attention to the advantages and disadvantages of the compressed air type and the self energy type when selecting the type. According to the operating conditions and development prospects of the system, the selection object should be determined through technical and economic comparison. The selection of the self energy SF6 circuit breaker cannot be coaxed up under the huge amount
while researching, developing and producing self energy SF6 circuit breakers, China's switch manufacturers cannot ignore and even avoid the improvement and perfection of the hydraulic mechanism. For the operation Department, it is a more practical work to solve the leakage problem of the hydraulic mechanism still in mass production and use as soon as possible