发电机低频注入式转子一点接地保护异常运行分析

针对石塘电站#1发电机转子一点接地保护运行时频发信号的问题,采用现场试验、录制电压波形等方法对保护装置和转子回路进行分析,寻找异常原因并进行了相应处理,彻底解决了转子一点接地保护频繁的误动.     

发电机转子动态接地的检查处理

介绍了新丰江发电有限责任公司3~#发电机发生转子动态接地故障的经过,转子动态接地故障的查找。本文重点介绍了新丰江发电有限责任公司3~#发电机转子发生接地后怎样动态查找接地点的方法,分析发电机转子发生动态接地的原因,研究排除接地故障的措施。     

发电机转子绕组一点接地故障的快速检查及处理

以实例介绍了应用电位分布法对小峡水电站发电机转子绕组一点接地故障快速检查及处理,对故障原因进行了分析,指出发电机转子绕组一点接地故障的危害。强调了在机组安装及检修过程中应严格执行相关工序工艺标准以及发电机风洞管理规定,对新安装及检修机组在投运前对发电机风洞认真检查验收,防止转子一点接地故障的发生。     

发电机中性点接地方式及运行分析

本文阐述了发电机中性点各种接地方式,并对其运行作了分析比较.在由大容量发电机构成的现代电网中,经副边带高电阻的配电变压器接地优于其它接地方式,这种接地方式亦将在我国广为采用     

三峡电源电站机组发电机转子绝缘降低故障及其处理

针对三峡电源电站水轮发电机组在初期运行中频频出现发电机转子绝缘降低的故障,分析了电源电站机组发电机转子绝缘降低的原因,介绍了技术改进的措施,总结了处理机组发电机转子绝缘降低故障的经验.     

发电机转子滑环烧毁的若干原因及预防

近期有若干发电厂相继发生了发电机转子滑环烧毁的事件,严重影响了机组的安全运行。根据发电机转子滑环的结构及工作特性,分析了发电机转子滑环烧毁的常见原因,对碳刷的检查项目和维护频率提出了一些建议,有效的避免了发电机转子滑环烧毁现象的发生,保证了发电机运行的安全可靠。     

水电站微机发电机转子接地保护装置的原理与设计

叙述了水电站综合自动化系统中微机发电机转子接地保护装置的基本原理、软硬件设计。本装置以高速高性能微处理机及实时多任务操作系统为基本开发手段，利用切换采样原理构成机组励磁回路一点和两点接地保护，测定转子接地故障点位置和过渡电阻的大小。     

一起水轮发电机转子动态接地故障及其处理

石龙水电站2号水轮发电机试运行时发生转子动态接地故障,由于动态接地点较难查找,若采用传统方法查找,工作量大,时间较长。文中介绍了一种简便有效、快速查找接地点的方法,并分析了产生动态接地故障的原因。     

9FA燃机发电机转子故障处理及分析

对发电机转子异响和接地故障实例进行分析,认为异响是由于一块绝缘塞块的固定片撕裂,造成绝缘塞块随转子低速旋转时在重力和向心力的共同作用下敲击护环所致;接地故障原因是由于内环极引线螺钉出现松动磨损,并产生大量含金属粉末覆盖在压帽以下的导电杆表面及转子本体绝缘层上。总结处理过程,供同类9FA电厂技术人员参考借鉴,便于对发电机转子故障情况的分析预判,制定最佳处理方案。     

兆瓦级风力发电机轴电压现场测量与分析

阐述了风力发电机轴电压产生的原因以及危害。结合兆瓦级风力发电机的现场实际安装,设计了相应的试验测量方案,并实测了轴电压和轴电流波形。采用专业软件对实测波形进行分析,通过比较其有效值、峰峰值以及FFT波形,结果显示出在不同接地方式下轴电压和轴电流存在差异;发电机转轴2侧接地电刷均接地时轴电压最小,电刷均不接地时轴电压最大;且轴电流在1 000 Hz和2 000 Hz处有明显的电流分量。在风力发电机运行期间,保证发电机的总体绝缘状况良好和转轴2侧的接地电刷可靠接地,以确保发电机正常可靠运行     

Analysis of operating conditions of ground-fault protection schemes for generator stator winding

This paper presents results of simulation studies of the influence of methods of grounding the stator winding of the unit-connected generator neutral on the operating conditions of a 100-percent ground-fault protection excited by the third-harmonic voltage ratio in the generator neutral and at its terminals. The analysis was performed for a generator with the neutral grounded through a ground-fault neutralizer, a third-harmonic stop filter, a resistor, and a capacitive voltage divider. The influence of the parameters of the particular elements of the grounding circuits on the voltage-feeding measuring element of the protection was determined. The capacitance to ground of the generator breakers was taken into account. The simulations were run for 1110-MVA unit-connected generator at ground faults along the whole length of the generator stator winding. It has been found that the method of grounding the generator neutral and the parameter of the grounding elements significantly influences the operating conditions of this protection. It is shown that through the proper selection of these parameters, the ground-fault protection of whole stator winding, counting from the generator neutral to the terminals is ensured.     

A novel technique for measuring grounding capacitance and groundingfault resistance in ineffectively grounded systems

A principle for resonance measurement based on injecting a resonant frequency signal is presented in this letter. Using this principle, the grounding capacitance of lines and equipment and the grounding fault resistance can be measured on-line in ineffectively grounded systems. Based on this, Petersen-coil automatic tuning is implemented and 100% stator grounding fault protection for generator stator windings is also proposed. The prototype for Petersen coil tuning has been tested on networks for many years. The new method for generator stator grounding fault protection is verified by simulation     

A brushless self-exciting three-phase synchronous generatorutilizing the 5th-space harmonic component of magneto motive forcethrough armature currents

A novel brushless self-exciting three-phase synchronous generator is proposed. It consists of three-phase armature windings on the stator, one field winding and one exciting winding with five times as many poles as that of the armature winding on the rotor, and a three-phase reactor connected to the terminal of the armature windings. By utilizing the 5th-space harmonic component of armature electromotive force, small voltage regulation for various loads and no oscillatory tension occurring at the rotor shaft were realized. The basic constitution, principle of operations, and exciting characteristics are described. The experimental results obtained from using a trial generator demonstrated its practical usefulness     

A Brushless, Self-Excited Single-Phase Synchronous Generator Operating with Load and Exciting Currents Flowing in Armature

This paper describes principles, analyses and experimental studies of a brushless and self-excited single-phase synchronous generator which was devised by one of the authors. The analyses and test results of performances of the generator system of which the armature winding is supplied with an exciting power from a transformer which is connected with the generator armature winding through a reactor or a condenser are presented. It can be found from the test results that the necessary exciting power is less in case of the armature winding supplied with DC exciting current from the transformer through the condenser.     

Ground-fault currents in unit-connected generators with differentelements grounding neutral

The results of the analysis of zero-sequence currents flowing in generator neutral and at ground-fault location during the generator normal operation and during ground-faults in the stator windings are presented. The influence of different methods of grounding the generator neutral on these currents in the primary circuits for different parameters of generators, transformers and additional capacitance to ground of the generator breakers was determined. This influence was analyzed for generators with ungrounded neutral, for generators with the resistance in neutral and for generators with ground-fault neutralizer (GFN) grounding the generator neutral. The analysis has been done for real resistance of the breakdown channel during ground-faults along the whole length of generator stator winding. It has been found that the applied method of grounding the generator neutral, the parameters of generator and transformer, the additional capacitance to ground of the generator breakers, level of fault resistance and ground-fault location have a substantial influence on currents flowing in the generator neutral and at ground-fault location in the breakdown channel in the main insulation of a generator stator winding     

A novel technique for measuring grounding capacitance and groundingfault resistance in ineffectively grounded systems

A principle for resonance measurement based on injecting resonant frequency signal is presented in this paper. The grounding capacitance of lines and equipment and the grounding fault resistance can be measured online in ineffectively grounded systems. Petersen-coil automatic tuning is implemented, and 100% stator grounding fault protection for generator stator windings is also proposed. The prototype for Petersen-coil tuning has been tested on networks for many years. In addition, the new method for generator stator grounding fault protection is verified by simulation     

基于光学电流互感器的发电厂保护优化研究

本文总结了采用柔性光学电流互感器的发电厂继电保护针对不同场景的优化研究和探索,介绍了发电机主保护方案优化、转子绕组匝间保护、选择性定子接地保护、核电辅助变断相监测保护、抽水蓄能等变频启动机组保护优化等保护优化方案和效果,利用柔性光学TA良好的传变特性和灵活的安装方式,较好地解决了现有发电厂保护存在的问题,可为现场类似场景的问题解决提供参考思路。     

双层叠绕组发电机单元件横差保护特性分析

通过1号机横差保护动作的现象,对故障进行分析,得出测量双星形中性点电流作为双层叠绕组发电机单元件横差保护的,横差动作的原因可能是定子绕组匝间发生短路,也可能是转子匝间短路或者转子偏心引起磁场不均匀也会引起的结论,该结论对现场维护人员有一定得指导意义。     

A brushless, exciterless, single-phase, sinusoidal wave synchronousmachine having an auxiliary stator winding

Analytical and experimental studies of a brushless, exciterless, single-phase, sinusoidal-wave synchronous machine operating as a generator or a motor, derived from a three-phase machine, are reported. One phase armature winding of the three-phase machine is used as an auxiliary stator winding of the single-phase machine and is used to supply the exciting power for the other two-phase armature windings acting as the load winding of the single-phase machine. A 1.5 kW, 200 V, 60 Hz, four-pole synchronous machine was used the experiments. It is shown that the waveforms of the armature terminal voltage and the load current are nearly sinusoidal. The advantages of the single-phase machine as a portable generator or small-load motor are discussed