核电机组励磁控制系统异常及仿真分析

针对某核电机组近期多次发生励磁控制系统异常的情况,收集了该核电厂DCS及PMU系统监控信息及故障实时曲线,发现励磁系统辅助强励回路设计存在缺陷。通过建立有和无辅助强励系统的核电机组励磁模型,分别以单机无穷大系统及实际电网运行方式开展仿真计算比对分析,计算结果表明无辅助强励功能的励磁系统能满足核电机组满功率送出及电网安全稳定运行要求,且各项性能均满足相关技术标准,由此提出了退出辅助强励的措施。实际运行情况表明,退出辅助强励后的核电励磁系统运行稳定,说明提出的措施可推广应用于其他同类型核电机组的异常问题处理。     

浅析发电机转子绕组接地原因及危害

上海某电厂配有四台联合循环机组,每台机组装机容量为400 MW,发电机为上海发电机厂制造,采用德国西门子同步交流发电机技术,冷却方式为水氢氢。发电机出口设有开关和闸刀,正常并、解列操作通过出口开关进行。励磁系统为自并励静止可控硅整流励磁系统,主要由励磁电源变压器、三相全控桥式整流器、灭磁开关等组成。以该电厂2020年7月至9月间#1、#2机组启动时多次出现发电机转子绕组接地报警为例,分析了接地原因、危害及最终的解决方案。     

330 MW发电机无刷励磁系统运行分析

从运行人员的角度出发,紧密结合现场实际,论述了蒲电二期汽轮发电机组无刷励磁系统及其附属系统的工作原理。分析比较了发电机无刷励磁系统与传统励磁系统,结果表明,发电机无刷励磁系统运行可靠性高,技术和经济性能优越。提出了蒲电二期发电机自并励励磁系统在设计方面存在的问题：监测旋转二极管运行情况的霍尔效应传感器易发生故障;发电机的励磁电流、励磁电压难以监视等。     

大唐石泉水力发电厂励磁系统技术改造

简述了大唐石泉水力发电厂1-3号水轮发电机组由原直流励磁机它励励磁方式改造为自并励静止励磁方式的思路和目的,介绍了技术改造后该系统的结构、性能、功能;并对该系统改造后的成效进行了简单总结。     

基于UN5000励磁起机过电压研究与优化

基于国内某电厂7号1 000 MW机组UN5000起励时出现的过电压造成过激磁保护报警和励磁机短路事件进行分析,通过逻辑优化解决机组起励时出现的过电压问题。该优化逻辑适用于同型号励磁系统的电厂,为使用UN5000励磁系统机组起励时出现过电压现象提供解决思路。     

核电厂应急柴油发电机1E级励磁系统设计探讨

介绍了核电厂应急柴油发电机组1E级励磁系统的总体性能要求和鉴定要求;开展了励磁系统安全功能的分析;阐述了新型可控相复励无刷励磁系统的基本架构和主要功能特性。重点介绍了相复励设计要点,实现安全功能的自动电压调节器和提高系统性能的不执行安全功能的辅助调节器的特点,以及1E级与N1E级电气隔离原则。为1E级应急柴油发电机数字式励磁系统设计和研发提供参考。     

自并励静止励磁系统在燃气轮发电机的应用

介绍了沙口发电厂燃气轮发电机自交励静止励磁系统的组成，性能及其特点，总结了运行和维护经验，指出了该系统存在的薄弱环节以及改进意见。     

发电机自并励静态励磁系统谐波特性分析

自并励静态励磁系统具有响应速度快、轴系短、振动小、成本低等特点,目前已成为国内外大型新机组优先选择的主要励磁方式,但自并励静态励磁系统在实际应用中存在谐波污染问题.文中主要分析了自并励静态励磁系统谐波产生机理,从理论和仿真的角度对该系统中产生的谐波特性进行研究,并通过现场测试结果验证理论分析与仿真结果的正确性,最后提出...     

针对UN5000励磁系统起励问题的研究与优化

针对电厂大型机组使用UN5000励磁机在起励时常出现的过电压造成过激磁保护报警,励磁系统逆变灭磁或跳闸后,没有完全灭磁情况下再次起励问题进行了研究,提出了一种新型励磁起机逻辑,通过进行内部逻辑优化可解决机组起励时出现的问题.该优化逻辑适用于当前所有使用相同型号励磁系统电厂,可为起励时出现过电压以及在没有灭磁情况下强行起...     

阻容保护在水电厂励磁系统的应用

介绍和分析了在丰满发电厂自并励励磁系统上应用的阻容保护的原理、设计选型和试验。通过阻容保护在丰满发电厂自并励励磁系统上的应用,保证了励磁系统和机组及电网的安全运行,提高了电厂运行的安全可靠性,取得了较好的经济和社会效益。     

Rotor design of a 1000 MW superconducting generator

A conceptual rotor design was developed for a 1000 MW superconducting generator having a high-initial-response excitation system. Field winding design, magnetic field analysis of the field winding, and loss calculations and force and stress analyses for the rotor body were carried out. The results are as follows: (1) the operating point of the field winding at the transient state is 72% of the short sample characteristics; (3) the stress in the rotor teeth at the steady state is 405 Pa; and (4) high initial response excitation can cause quenching of the field winding, so the shaft should have a higher resistivity. The maximum flux density at the field winding end region can be small due to optimum magnetometer force distribution     

1100MW核电发电机转子长、短护环结构计算及比较分析

1 100 MW核电发电机是未来几年发展的主力机型,转子作为发电机中最关键的零部件,其运行时承受巨大的离心应力(本身旋转)和短路力矩(来自于电网)的作用,直接影响到发电机的安全运行;护环是汽轮发电机转子中承受应力最大的一个部件,为确保护环在运行中安全可靠,有必要对其在各种状态下的应力进行分析。主要通过ANSYS对1 100 MW级核电汽轮发电机的护环装配进行机械计算,对长搭接护环、短搭接护环进行计算和比较分析,并选取合适的过盈量以使得护环装配体中的各部件能满足设计要求,根据分析结果优化选择护环设计结构。     

采用再热温度630 ℃的1 000 MW新一代超超临界二次再热机组可行性研究

[目的] 为了推动采用再热温度630 ℃的1 000 MW新一代超超临界二次再热机组发展,需对某沿海电厂2× 1 000 MW新一代超超临界二次再热机组的可行性进行研究。 [方法] 文章分析了主机参数、主机技术条件、主机设备可行性、辅机设备可行性、主要系统配置、机组经济性和热经济性指标。 [结果] 研究表明：1 000 MW新一代超超临界二次再热机组是可行的,已具备示范应用条件。与1 000 MW常规超超临界二次再热机组相比,1 000 MW新一代超超临界二次再热机组热效率更高,污染物排放更少,经济效益较高。该1 000 MW新一代超超临界二次再热机组热效率达到48.72%,发电标煤耗达到252.48 g/kWh,供电标煤耗达到260.16 g/kWh,为国内最优水平。 [结论] 我国具有自主知识产权的先进马氏体耐热钢G115和带小发电机的抽背式给水泵汽轮机可以应用于新一代超超临界二次再热机组。     

大型发电机转子轴系横振评判标准分析

为了保证大容量汽轮发电机组转子轴系在电厂的长期安全运行,其横振特性在设计及运行阶段均须满足相应的评判标准.总结了国内外标准及行业标准中对于发电机组转子轴系横振特性的评判要求,运用Riccati轴系传递矩阵法分别计算了600 MW、1 000 MW等级大型发电机组轴系临界转速,并结合权威测试机构对机组的现场升降速试验数据进行了调研,将多组计算和试验得到的转子轴系临界转速与相关标准进行了对比.分析结果表明,现行横振评判标准具有较好的适用性,并建议可将频率、响应、敏感度等指标结合,以评判发电机组横振特性的优劣,进一步提高标准的适用性,从而提高大型汽轮发电机组轴系设计的可实现性.     

300MW机组在机电耦合冲击作用下的扭振控制特性考核

建立了汽轮发电机组转子轴系的阶梯轴弹性连续体扭振模型。利用求解复杂阶梯轴系扭振响应波动方程的方法对 1台 3 0 0 MW汽轮发电机轴系在外部载荷作用下的扭振响应进行了计算机模拟考核 ,并采用最小能量法对机组转子轴系进行了主动控制模拟研究。图 1 2表 3参 3     

Modeling of emergency diesel generators in an 800 megawatt nuclearpower plant

Computer models have been developed of emergency diesel generators and their associated emergency core cooling system induction motors during sequencing and results compared with field tests. Models required to perform studies of emergency diesel generators in a nuclear plant are presented. Field measurements indicating different response of two seemingly identical generator excitation systems are discussed. Results of 480 volt AC contactor dropout testing are provided for determining voltage limits in the 480 volt system during motor starting transients     

百万级核电汽轮机高压外缸汽封接管焊接工艺的研究

介绍了百万级核电汽轮机高压外缸汽封接管焊接工艺的试验研究过程,从焊前装配、焊接工艺方法和焊接操作等方面阐述了实际的生产过程,为核电汽轮机汽缸的生产总结了宝贵的经验.     

Stressing of turbine-generator-exciter shafts by variable-frequencycurrents superimposed on DC currents in asynchronous HVDC links andfollowing disturbances at converter stations

Ripple currents on the DC side of both HVDC synchronous and asynchronous links together with cleared HVDC and AC system disturbances can excite in some circumstances onerous torsional vibrations in large steam generator shafts. The problem has assumed importance in recent months on account of the HVDC link between Scotland and Northern Ireland going ahead, on account of the proposed Eire/Wales link, and because AC/DC/AC couplers are to be installed extensively to interconnect the East and West European grid systems. This paper discusses and analyses excitation of shaft torsional vibrations in steam turbine-generator-exciter shafts in close proximity to HVDC power converter substations by: (i) variable-frequency ripple currents superimposed on the DC currents in asynchronous links; and (ii) disturbances at bi-polar converter stations. Detailed simulation of the HVDC converter and generator is necessary for precise assessments of shaft torsional response following HVDC converter station faults. 500 MW, 660 MW, 1000 MW and 1300 MW machines are considered in the analyses that are made     

Turbine, generator, system modeling and impact ofvariable-frequency ripple currents on torsional stressing of generatorsin Poland and Sweden: Lithuania/Poland and Sweden/Poland HVDC links

This paper analyzes rectifier ripple current superimposed on the direct current of a 600 MW asynchronous bipolar link between Lithuania and Poland and a 600 MW asynchronous monopolar link between Poland and Sweden in evaluating possible torsional vibrations in steam turbine-generator-exciter shafts. The studies are performed for machines in Northeastern Poland and in Southern Sweden close to the inverter station which are most at risk. Analyses are performed for the generators in Poland for the Lithuania/Poland link and for the generators in Sweden for the Poland/Sweden link. The paper examines system scaling factors for the Lithuania/Poland Link. It then examines AC system scaling factors and generator scaling factors for modulation product harmonic currents impressed on generators connected to the Swedish Grid Network by the inverter. Amplitude of shaft torsional torque due to resonant excitation imposed by the link on the generators in Sweden is evaluated for different scenarios of system and generator load. First, theory which relates magnitude of harmonic AC current injected into the AC system by the inverter is summarized. Dispersion of the injected harmonic AC current to proportion the current to individual generators is then reviewed, considering impedance of the generators, loads, and other system elements. Significance of simple and detailed shaft train models of machine shafts as well as approximate (Id, Iq) and detailed (2d, 3q) generator damper models on resonant torques is reviewed. Then, effects of both power factor and generator load on generator scaling factors is illustrated