同步发电机励磁绕组匝间短路计算及保护的研究

项目名称： 同步发电机励磁绕组匝间短路计算及保护的研究

项目编号： No.50807027

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 孙宇光

作者单位： 清华大学

项目金额： 22万元

中文摘要： 本项目着力解决以往无法定量计算发电机转子匝间短路故障电气量的研究瓶颈，探索故障监测的原理和方法，以此为发电机的停机检修决策提供准确的量化依据。主要研究内容包括：1）对转子匝间短路故障的电气量进行准确的定量计算，并通过实验进行验证；2）全面地归纳各种发电机的故障特征，并分析其产生原因；3）故障监测的原理、方法和定值。 主要研究成果包括：1）建立了同步发电机转子匝间短路故障的扩充的多回路数学模型，准确计算了与故障的励磁绕组有关的电感参数，利用数值算法实现了凸极和隐极同步发电机故障暂态过程的数字仿真，并通过实验结果验证了暂态仿真方法的准确性。2）通过理论分析并结合实验与仿真，得到了各种发电机励磁绕组匝间短路的稳态故障特征，并论证了其异于其它常见故障的独特性，获得了转子匝间短路故障监测的理论依据。3）建立了各种发电机转子匝间短路故障的通用稳态数学模型，并针对定子绕组的不同形式，通过理论推导与化简，降低了稳态数学模型的阶数，实现了大型水轮发电机励磁绕组匝间短路故障稳态的快速准确求解。4）提出了基于相绕组内部不平衡电流谐波分量总有效值的故障在线监测方法，并探讨了兼顾可靠性与灵敏性的定值整定方法。

中文关键词： 同步发电机；转子匝间短路；扩充的多回路模型；故障特征；在线监测

英文摘要： This project aims to break the bottleneck in quantitative calculation on electrical states for the synchronous generator with inter-turn short circuits in field winding, and searches for fault monitoring principles and methods to provide quantitative criteria for the decision-making of maintenance outage.The research contents of this project are: 1) Quantitative calculation on fault currents of stator and rotor windings, and experiment verification for the calculation accuracy; 2) Fault characteristics and their causes; 3)Principles, methods and setting values for fault monitoring. The main achievements of this projects are as follows: 1) An extended multi-loop mathematical model is established, in which inductances of the field windings with inter-turn faults are accurately calculated, and transient simulation of the whole fault process is realized by means of computer numerical methods for both salient pole and non-salient pole machines, which is verified by detailed experiment data. 2) With theoretical analysis combining experiment and simulation results, steady-state characteristics of the faults are summarized for various synchronous generators, which may serve as the basis for the fault monitoring for inter-turn short circuits of field windings due to their differences from other common faults. 3) An general steady-state mathematical model is established for various synchronous generators, whose order is reduced through theoretical deduction and mathematical simplification according to the pattern of stator winding, with the help of the model steady-state currents of large hydro-generator with inter-turn short circuits in field winding could be worked out quickly. 4) On-line fault monitoring method is proposed in view of the effective value of unbalanced currents of stator branches in the same phase, which contains fractional harmonics instead of fundamental component in theory, and ways for value setting is explored considering both reliability and sensitivity.

英文关键词： synchronous generator; inter-turn short circuits of field windings; expanded multi-loop mathematical model; fault characteristics; on-line monitoring