一种新型的小汽轮机给水泵变速恒频发电系统

为节能减排,火力发电厂采用主汽轮机再热蒸汽驱动小汽轮机带动锅炉给水泵供水,通过调节小汽轮机进汽阀开度的方式来控制转速。但该方案在阀门处产生节流损失,轻载时对系统效率影响更大。为此,提出一种小汽轮机、给水泵和电机三者同轴连接结构,用全功率变流器驱动电机,实现给水泵变频调速,并将剩余能量馈回电网,实现节能。运行时阀门全开,调节电机电磁转矩来吸收轴系功率,平稳快速控制给水泵速度,避免阀门损耗。从汽轮机-给水泵的转速转矩及机械耦合特性出发,建立了该发电系统的数学模型,针对工况切换下的调速要求,研究了运行稳定性和抑制功率波动尖峰的控制策略及控制参数设计。最后通过仿真分析以及小功率系统的物理动模实验,验证了系统运行的可行性和有效性。     

Modeling, simulation and control of wind turbine driven doubly-fed induction generator with matrix converter on the rotor side

In this paper, a wind energy conversion system, which consists of a variable speed wind turbine with doubly-fed induction generator (DFIG) fed by a matrix converter is considered. The stator of the wind turbine driven generator is directly connected to the grid, while the rotor is connected via slip-rings to the output of a matrix converter. The matrix converter is supplied from the grid and replaces the conventional two back-to-back converters used for the control of a DFIG. Modeling of the energy conversion system considers super-synchronous and sub-synchronous operating conditions, which are achieved by means of the matrix converter. In order to decouple the active and reactive power, stator field oriented control is applied. Speed mode control is adopted for maximum wind energy extraction, provided that the wind speed and pitch angle of the turbine are known for each sampling period. Consequently, a 2-D lookup table calculating the reference speed by means of interpolation/extrapolation is introduced. Reactive power control is performed so that the stator reactive power is kept to zero. Promising simulation results demonstrating the control performance of the wind energy conversion system are presented.     

300MW CFB锅炉无电泵的启动实践

红河发电公司300 MW循环流化床锅炉给水泵系统配置有两台汽动给水泵并列运行时,可供给锅炉100%BMCR的给水量;一台50%BMCR容量的电动给水泵作备用。红河发电公司2号锅炉在这次启动过程中,电动给水泵电机烧毁无法投入使用,1号机组也处于停机状态,采用启动锅炉汽源作为除氧器加热和机组轴封汽源、汽动给水泵的备用汽源,锅炉升压后通过汽轮机高旁、低旁配合调节,保证再热蒸汽压力在0.6～0.8 MPa之间,用本机的冷再汽源作为汽动给水泵的汽源冲转,通过汽动给水泵向锅炉汽包上水,顺利完成了机组的启动工作。     

A Self Commutated Power Converter for Stabilizing Torsional Interactions

A recently proposed method of counteracting torsional interactions referred to as transmission current feedback involves the measurement of the transmission system currents from which the subsynchronous components that produce torsional interactions are extracted. Once extracted, these are suitably amplified by a power converter and injected into the generator bus of the affected steam turbine so as to cancel the original subsynchronous components which would otherwise produce torsional interactions. In this paper, a power converter capable of supplying the required subsynchronous currents is described. An analytic model relating the converter output currents to its controlling variables is derived and a suitable control strategy is formulated. A detailed hybrid computer simulation of the converter is used to verify the accuracy of the analytic representation of the converter and the effectiveness of the control strategy.     

百万千瓦级超超临界汽轮发电机试验站拖动系统的方案选择

百万千瓦级超超临界汽轮发电机试验站拖动系统的选择既应满足最大容量等级汽轮发电机的拖动要求,同时也应尽量满足各种不同容量等级的汽轮发电机试验时的能源节约要求。拖动系统不仅要满足汽轮发电机的起动要求,同时也应保证汽轮发电机紧急时刻的安全刹车。拖动系统采用两台异步电动机联合运行方案,6MW异步电机由变频器供电,用于被试汽轮发电机的起动、制动,11MW异步电机挂网运行与6MW异步电机联合拖动,共同承担短路试验的负荷。     

兆瓦级风力机特性模拟器

针对传统的风力机特性模拟器只能对等功率风力机特性进行模拟的缺点,开发了一套新型的兆瓦级风力机模拟器实验平台。首先对实际风力机静态和动态转矩特性进行了分析,搭建了由变流器、异步电机和减速箱构成的风力机模拟实验平台,采用矢量控制方案分别对异步电机和发电机进行转矩和转速控制,使减速机输出的转速符合兆瓦级风力机实际运行的工况特性。在MATLAB/Simulink环境中,分别对风速变化和转速变化2种情况进行了仿真分析,结果表明该方案能准确模拟兆瓦级风力机的运行特性。     

Technical possibility and advisability of involving a T-250 cogeneration power unit into control of frequency and power in a power system

Studies carried out on a model of a T-250 power unit used as part of a computer-based training simulator are presented. The adequacy of the adopted model is estimated, and the power unit operating modes are analyzed in which the requirements of selective primary and automatic secondary control of frequency can be satisfied. Changing the flowrate of steam extractions from the turbine by producing inputs to the control valves in the bypass of the group of high-pressure steam lines and varying the supply of steam to the high-pressure steam lines and to the feedwater pump’s turbine drive are considered as control inputs for changing the power unit load along with commonly adopted variations of boiler load (with producing control input to the boiler power controller) and turbine load (with producing input to the power controller, which works out commands to the turbine control valves). The need of using combined control is also confirmed.     

引风机三种驱动方式分析

引风机多采用电机驱动,为节能减排,一种方案对引风机电机增加变频装置,另一种方案对引风机采用汽轮机驱动方式,对比两种节能驱动方式,介绍每种驱动方式系统构成和运行方式。分析两种节能方案的投资回收年限,电厂可根据综合比较结果选用节能驱动方式。     

350MW机组汽轮机强制冷却分析

介绍了沙角B电厂汽轮机在计划性检修停机过程中,利用蒸汽强制冷却和停机后再用压缩空气冷却的方法和过程。蒸汽强制冷却和压缩空气冷却方法的结合使用,大大减少了停机后汽轮机的冷却时间,为缩短机组检修工期创造了有利条件。     

兆瓦级风力机风轮静态特性模拟器的研究

提出一种新型小功率实验平台模拟兆瓦级风力机风轮特性的控制策略.通过对兆瓦级风机转矩特性等功率缩小和低转速特性的准确跟踪,实现风力机风轮静态特性的模拟.利用原动机侧变换器能够模拟兆瓦级风机缩比转矩特性,发电机侧变换器可准确跟踪风机低转速特性.分别针对风速和转速变化两种情况进行了分析,结果表明该方案能准确模拟兆瓦级风力机风...     

Achieving More Efficient and Reliable Operation of Geothermal Turbines by Using a Secondary Flash Steam Superheating System

Problems encountered in operation of saturated steam geothermal turbine units that stem from the specific features of a geothermal heat carrier are considered. A two-phase state, increased content of salts, and corrosiveness of geothermal working medium have a negative influence on the efficiency and reliability of the turbine’s first and last stages. Owing to high concentrations of impurities in the liquid phase, the first stages suffer from intense generation of deposits. The resulting decrease in the power output is due to both fouling of the flow path and significantly growing roughness of the turbine cascade blades. The flow of wet steam in the geothermal turbine flow path is accompanied by droplet impingement erosion of the last-stage blades and corrosion fatigue of the metal of rotor elements. In addition, the losses due to steam wetness in the flow path cause an essential decrease of the geothermal turbine efficiency. The article gives examples of erosioninduced damage inflicted to the last-stage rotor blades, corrosion fatigue of the metal of integrally-machined shroud elements, and deposits in the nozzle vane cascades of geothermal turbine stages. The article also presents the results from numerical investigations of the effect that the initial steam wetness has on the silicic acid concentration in the wet steam flow liquid phase in a 4.0 MW geothermal turbine’s stages. A method for achieving more efficient and reliable operation of the geothermal turbine low-pressure section by applying a secondary flash steam superheating system with the use of a hydrogen steam generator is proposed. The article presents a process arrangement for preparing secondary flash steam supplied to the geothermal turbine low-pressure section in which the flash steam is evaporated and superheated through the use of a hydrogen steam generator. The technical characteristics of the system for preparing secondary flash steam to be used in the intermediate inlet to the turbine were preliminarily assessed (taking the upgrading of the Mutnovsk geothermal power plant as an example), and it has been shown from this assessment that the wetness degree in the low-pressure section can be decreased down to its final value equal to 2.0%.     

风力机风轮模拟实验平台的设计

对于风力发电技术的研究,一套完整的风轮机输出特性模拟系统的建立是重要的环节,通过建立风速和风轮机转矩数学模型,利用组态王软件进行模拟,将信号传送给变频器来控制异步电机进而模拟风轮机的输出特性。实验结果表明,该模拟系统具有良好的动态性能和可行性,适用于风力发电系统的相关研究工作。     

200MW机组给水泵的改造及经济性分析

介绍了我国首台 2 0 0MW机组给水泵的改造情况 ;对相同条件下的汽动给水泵 (以下简称汽动泵 )和电动给水泵 (以下简称电动泵 )进行了经济性对比分析 ;提出了提高汽动泵经济性的措施 ,对 2 0 0MW机组汽动泵改造进行可行性探讨。     

600MW超临界机组运行优化分析

通过研究改进超临界机组多项运行操作方式,达到节能降耗目的。主要对以下四个方面进行改进:降低给水流量,达到降低锅炉启动汽温的目的;高压加热器逆止门改造及滑压启动,展现多项优点;减少锅炉启动用油,节约启动成本;降低一次风母管压力,减少厂用电。实施后降低锅炉汽温30℃以上,有效解决机、炉汽温匹配问题;高加管壁温升得到科学控制,间接解决汽机冲转时上下缸温差高问题;每次启停机节油45t;一次风机电流降低20 A。为同类型电厂运行操作优化提供参考依据和借鉴。     

Methods for tuning the unit used in a boiler power controller for dynamically converting the live steam pressure signal

Two methods are proposed for tuning the dynamic converter that produces an additional signal in the boiler power controller proportional to the time derivative of live steam pressure upstream of the turbine p′ _t using the power unit’s transient characteristics, and a comparison between these tuning methods is carried out.     

风电变流器中IGBT的可靠性研究

风力发电机组中的变流器,其运行工况特殊,功率、频率、电流、电压等参数随风的变化而变化.由于变流器工况变化频繁,引起功率器件的结温和壳温频繁波动,造成器件的功率循环和热循环损伤较大.另一方面,高海拔地区丰富的风资源,为风电变流器的高海拔运行提供了广阔空间,而高达4 km海拔的应用,让宇宙射线对功率器件的损伤不容忽视.大功...     

25MW汽轮机转子掉叶片的配重处理

针对某热电厂25MW汽轮机组运行中突发掉叶片事故,提出对汽轮机转子进行平衡配重处理,通过计算、称重、加装等步骤使汽轮机在短期内完成了抢修,重新投入了生产运行;并介绍了该汽轮机检修加配重处理的过程及方法。实践表明:采取临时加配重处理不失为一种较好的选择。     

Heat flow diagrams with and without a deaerator for steam turbine plants with T-250/300-23.5 turbines

A T-250/300-240 turbine (currently known as T-250/300-23.5), which is operated at 31 steam turbine plants, is the largest in the world extraction turbine (by the heating extraction load) and one of the largest by the nominal capacity. All steam turbine plants equipped with T-250/300-23.5 turbines of different modifications are operated in large cities of Russia and the neighboring countries covering a significant part of the needs of cities for the electric power and almost fully supplying them with heat power. The design life of a significant part of the operated steam turbine plants of this family is either expired or almost expired. It refers to both the turbine unit (including a turbine and a generator) and the turbine plant equipment. For steam turbine plants equipped with T-250/300-23.5 turbines, which were initially designed and mounted for work with deaerators at electric power stations, the heat flow diagrams with and without a deaerator were compared. The main advantages and disadvantages of each scheme were shown. It was concluded that, for the newly constructed power units with supercritical steam parameters, it is preferable to use the heat flow diagram without a deaerator; for the upgraded blocks, if there are no objective reasons for the removal of a deaerator, it is recommended to keep the existing heat flow diagram of a turbine plant.     

The cogeneration steam turbine of the T-63/76-8.8 type for a series of PGU-300 combined cycle power plants

This paper describes in detail the design of the T-63/76?C8.8 steam turbine manufactured by Ural Turbine Works (refurbished significantly), its electrohydraulic control and protection system made according to the current requirements on control and protection, the heat flow diagram, and arrangement of the turbine. The T-63/76?C8.8 steam turbine is intended to be used in double-shaft double-circuit combined-cycle monoblocks at a number of thermal power plants currently under construction. The turbine has a great future, since it may be employed in various combinations with gas turbine units having the output of 150?C170 MW that are manufactured by virtually all firms.     

高速大功率电机高效率低噪声离心风扇的研究与设计

在YKK560-2/10kV/1000kW三相异步电动机离心式外风扇叶片设计中成功地应用了固定翼飞机机翼结构形状、轴流式风扇叶片和汽轮机叶片形状,从而设计出高效率、低噪声的新型离心式外风扇。