【作者】 徐家贺；

【导师】 苑舜； 蔡志远；

【作者基本信息】 沈阳工业大学 ， 电机与电器， 2009， 硕士

【摘要】 发电机断路器是安装在发电机与升压变压器之间的保护电器,它不仅对发电机和主变压器起保护作用,而且对发电机组启停、维护以及增大运行灵活性和可靠性等起到积极的作用。由于发电机保护断路器工作场合的特殊性,对其可靠性有极高的要求,永磁操动机构结构简单、零部件少、可靠性高、操作寿命长、动作分散性小,已经广泛应用于中等电压等级的真空断路器上。本文重点研究了能与17.5kV/10000A/80kA型大容量真空发电机出口断路器良好配合的永磁操动机构。本文首先介绍了永磁操动机构的工作原理,对比了现有两种结构的永磁操动机构的优缺点,设计了一种非对称式双稳态永磁操动机构,并应用有限元软件Ansoft Maxwell,对永磁操动机构的静态保持力和静态磁场进行了分析和计算,分析和计算的结果表明非对称式结构所需的合闸启动电流远小于对称式双稳态永磁操动机构的启动电流,证明了非对称式双稳态永磁操动机构结构的合理性。本文还对所设计的非对称式双稳态永磁操动机构的动态特性进行了数学建模与分析,给出了动态微分方程组。通过Ansoft软件的瞬态求解器,获得了一系列动态特性曲线,为样机的设计提供了理论指导。研究了分闸线圈的线径变化对永磁操动机构动特性的影响,为线圈参数的优化设计提供了理论指导。为了减小分闸电流和触动时间,提高永磁操动机构的刚分速度,提出了双线圈并励磁的方法。对所设计的样机进行了机械特性试验,试验结果表明,各项指标均符合设计要求。大电流下的触头熔焊问题是17.5kV/10000A/80kA型大容量真空发电机出口断路器需要解决的一个难点,动熔焊是由触头弹跳所产生电弧热而引起的,解决触头弹跳问题是本文的一个重点。通过对减小触头弹跳措施的分析,采用双线圈串励磁合闸的方式,来降低触头的刚合速度,以达到减小触头弹跳的目的。试验结果证明了这种励磁方式的有效性。更多还原

【Abstract】 The generator breaker is the protecting equipment installed between the generator and the transformer booster. It not only protects the generator and the main transformer but also exerts postive influence on the starting and stopping of the generator, the maintainence of equipments and improving the flexibility and reliability of the generator. Due to the special working conditions, the generator is required of high reliability. Permanent magnetic actuator, possessing advantages of simple structure, fewer components, high reliability, long working life and operational centrality, has already been applied widely in the medium voltage vaccum circuit breaker. This paper mainly makes research on the construction of the permanent magnetic actuator, which works well with the 17.5kV/10000A/80kA high capacity vacuum generator circuit.This paper,first of all, has introduced the working mechanism of the permanent magnetic actuator and makes comparision of the advantages and disadvantages between two kinds of permanent magnetic actuator, and then it proposed the asymmetric bistable permanent magnetic actuator and the use of finite element software Ansoft Maxwell, which analysed and calculated the close circuit starting current and the static retentivity of permanent magnetic actuator. The result shows that the close circuit starting current of construction is far less than the starting current required by symmetrical bistable permanent magnetic actuator, proving the rationality of this construction.This paper also analysed the dynamic characteristics of the proposed asymmetric bistable permanent magnetic actuator and builded a mathematical model of dynamic differential equation. A set of dynamic curve can be abtained to provide the theoretical guide by the transient solver of Ansoft Software. The research, after studying the open coil and closing coils’influence on the external characteristics of permanent magnetic actuator, also provided theoretical guide for the optimization design of setting the coil parameter. In order to reduce the open coil current and the touching time, and improve the just open speed of the permenant magnetic actuator, this experiment proposed the use for twin coil in the shunt field which had shown that the use of twin coil.After conducting experiments on the designed model, the test results showed that all the indexes complied with the requirements.The contact terminal will melt down under heavy current, which is a problem of the breaker of 17.5kV/10000A/80kA high capacity vacuum generator circuit. The puddle welding is caused by the voltaic arc heat produced by the bounce of the contacting terminals. This is also the key problem of this paper to solve. In the end, after analysing the measures of reducing the bounce of the contact terminals and taking the way of series excitation twin coil with closed circuit,which aims at reducing the speed of just close, the experiment has proven the effectiveness of the excitation .更多还原