斯坦福发电机_斯坦福发电机维修_斯坦福发电机维修保养.doc

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1、斯坦福发电机维修保养康明斯发电机技术系统有50多年成功地满足顾客需要的经验，是世界交流发电机技术的先导，康明斯发电机技术系统拥有全球销售和服务网络，并在英国、美国、中国、印度有生产工厂。无锡工厂完全按照康明斯发电机技术系统的设计及工艺标准来制造斯坦福交流发电机。产品设计、材料、生产、试验均由英方人员直接管理控制。体积小，重量轻，技术先进，性能可靠是斯坦福发电机的重要特性。 康明斯发电机技术系统制造的斯坦福发电机可与世界上所有柴油机配套，如康明斯、帕金斯、VOLVO、MTU、道依茨、卡特彼勒和国产95、130、135、150、190系列等柴油机。各系列产品成功供应发电机组成套厂家，广泛应用于铁路

2、、船舶、邮电通信、军工、油田、交通、高层建筑及冷藏集装箱等领域。 康明斯发电机技术系统所生产的发电机系列为:BC16、BC18、UC224、UC274、HC4、HC5、LV6、HC7。功率范围为:6.5KW2000KW。HC系列的发电机为无刷旋转磁场结构，电压最高达660V/50HZ或60HZ，满足BS5000标准第三部分和其他国际标准。在HC4,HC5,HC6/LV6,HC7四个机座号中，200KW-2000 KW范围内，可选1500rpm(50HZ)或1800rpm（60HZ）、4极的发电机。在HC6/LV6和HC7两个机座号中，224KW-1300KW范围内，可选1000rpm（50HZ

3、）或1200rpm(60HZ)、6极的发电机。机座号位HC4和HC5的发电机，其励磁系统可为使用AS440或SX421AVR的定子供电或为使用MX341或MX321AVR的永磁发电机（PMG）励磁，机座号位HC6/LV6和HC7的发电机使用MX341或MX321AVR的永磁发电机（PMG）励磁系统。自励AVR控制的发电机，主机定子通过AS440（或SX421）AVR为励磁机磁场提供励磁源，AVR是调节励磁机磁场励磁电流的控制装置。AVR根据来自主机定子绕组的电压感应信号作出反馈，通过控制低功率的励磁机磁场调节励磁机电枢的整流输出功率，从而达到控制主机磁场电流的要求。AS440AVR通过感应两相

4、平均电压，确保较高的电压调整率，除此之外，它还监测发动机的转速，如低于预选转速（HZ）设定，则相应降低输出电压，以防止发动机低速时的国力，缓减加载时的冲击，以减轻发动机的负担。SX421除了AS440的特点外，还具有三相均方根感应的特点，在与外部断路器（装在开关板上）一起使用时，它还提供过电压保护。永磁发电机（PMG）励磁发电机通过MX341(或321)AVR为励磁机提供励磁源，AVR是调节励磁机励磁电流的控制装置。如果是MX321AVR，则通过一个隔离变压器向来自主机定子绕组的电压感应信号作出反馈，通过控制低功率的励磁机磁场，调节励磁机电枢的整流输出功率，从而达到控制主机磁场电流的要求。PM

5、G系统提供一个与定子负载无关的恒定的励磁电源，提供较高的电动机启动承受能力，并不受非线性负载（例如可控硅直流电动机）产生的主机定子输出电压的波形畸变的干扰。MX341AVR通过检测二相平均电压来确保较高电压的调整率，另外它还检测发动机转速，如低于预选的转速设定，则相应降低输出电压，以防止发动机低速时的过励，缓减加载时的冲击，以减轻发动机的负担。它还提供延时的过励保护，在励磁机磁场电压过高的情况下对发电机灭磁。MX321除提供MX341巨友的保护发动机的减荷特性外，还具有三相均方根检测和过电压保护的特点。STAMFORD 发电机是按照国际最高质量标准,配备精心选择的零部件,采用先进的世界级工艺制

6、造而成。其能适应恶劣环境的全H级绝缘和最佳效率设计的绕组尤其适合于特殊场合的应用,标准的12个可重接出线头确保满足各种电压要求。国际品牌、人性化设计和一流服务使STAMFORD拥有众多的终身客户和广阔的应用领域。发电机励磁系统典型事故分析1. 保护装置误报“转子回路一点接地”故障处理（1）故障现象：励磁调节器起励，发电机机端电压逐步建立，经过一个过渡过程后趋于稳定值，然而此时保护装置报“转子回路一点接地”故障，发电机运行正常。利用转子电压表通过测量发电机转子正、负极对地电压，两极对地电压均不为零，说明发电机转子没有发生一点接地故障。按保护装置的复归按钮，“转子回路一点接地”故障信号消失。 （2

7、）故障分析： 分析保护装置中“转子回路一点接地”动作原理知道，保护装置根据转子电压判断转子接地故障。当励磁调节装置刚起励时，发出初励电源投入命令，转子电压升高，发电机电压上升，经过一段时间延迟后，励磁调节装置自动退出初励电源，由于励磁调节器机端电压初始参考值低于初励电源产生的机端电压，所以当初励电源退出后，转子电压会突然下降很多，进而转子电压反馈给保护，则保护装置认为是转子回路发生了短路致使转子电压突然下降了，所以保护报信号。将励磁调节器逆变灭磁后重新做试验，在励磁调节器起励前，手工增加励磁调节器电压参考值，保证大于初励电源产生的发电机端电压，重新起励升压后，发电机运行正常，保护装置没有发“转

8、子回路一点接地”故障报警。 （3）故障处理： 本次事故说明保护装置的“转子回路一点接地”功能不够完善，其动作机理不够科学，容易误动，建议完善“转子回路一点接地”功能，或者更换为更为可靠的“转子回路一点接地”保护装置。 在“转子回路一点接地”保护功能未完善前，调整励磁调节装置起励初始参考值，要求电压初始参考值大于初励电源产生的发电机端电压。2. 正常调节有功功率引起机组解列的事故处理（1） 事故现象：某电厂发电机组正常运行中，根据中调要求进行升负荷操作，在增加有功功率过程中，发电机输出无功功率由50MVar突然降低至-80Mvar，励磁调节装置发出低励限制信号，发变组保护装置报失磁保护动作，发电

9、机解列，灭磁开关跳闸。 （2）事故分析： 事故发生后，检查所有的保护及异常信号，发变组保护装置除了失磁保护动作外没有其它任何事故报警，故障录波显示事故障发生时，发电机机端电压下降，无功功率进相至80Mvar，失磁保护正确动作； 励磁调节装置除了发出低励限制信号没有其它事故报警信号，从励磁调节装置录波分析显示，励磁调节装置中电力系统稳定器输出突降至下限幅值（5%额定机端电压），发电机无功急剧下降，进相运行后，励磁调节装置低励限制启动，但未来得及调节，发电机进相深度已满足失磁保护动作条件。 根据当时只有有功功率增加操作，发电机励磁调节器采用PSS-1A型电力系统稳定器，因此分析认为事故的发生是因为

10、PSS反调引起的。对于PSS-1A型电力系统稳定器来说，PSS本身无法判断发电机有功功率的增加是系统低频振荡引起的还是由原动机调节引起的，当原动机增大有功功率输出，PSS输出会降低发电机励磁电流，进而降低发电机无功功率，这就是PSS-1A型的“反调”现象。PSS-1A根据有功功率的变化调节发电机励磁电流，当发电机有功功率向上变化时，其“反调”幅度与有功功率变化幅度成正比，由于本次增加发电机有功功率幅度较大，速度较快，PSS的“反调”直接导致励磁电流的突然降低造成深度进相，导致发电机失磁保护动作解列。 （3）事故处理： PSS-1A的“反调”现象对电厂和系统都是不利的，对于PSS-1A型电力系统

11、稳定器可以在调节有功功率时增加闭锁PSS输出的功能，但目前电力系统不推荐这种方法；要消除这种“反调”现象最有效的方法就是采用PSS-2A或PSS-2B模型，目前国内外多家励磁调节器已具有该类模型电力系统稳定器，并在工程中得到大量使用。对励磁调节器的低励限制功能进行完善，事故过程励磁调节器最先发出低励磁限制信号，但由于低励限制功能作用太慢，没有限制发电机无功功率降低才导致发电机失磁保护动作，目前业界中低励限制调节方法有两种：一种采用在低励限制时增加电压参考值的方法限制无功功率下降，这种方法调节过程较平稳，但调节速度较慢；另一种在低励限制动作时直接切换为无功功率闭环调节，根据无功功率下降的幅度及速

12、度进行调节，这种方法调节速度快，有助于发电机无功功率快速恢复至正常运行范围。3. 无功调差参数设置不一致切换导致发电机误强励事故分析（1） 事故现象：某电厂200MW机组处于发电状态，有功200MW，无功+100Mvar。励磁调节器正常工作中，A通道为主通道，B通道为从通道，处于备用状态，励磁调试人员观察励磁电流，进行通道切换试验，通道切换命令（A通道至B通道）发出后，励磁电流突然增大，励磁变压器保护动作，作用于发电机解列跳闸。 （2） 事故分析： 事故发生后，检查B通道和励磁变压器保护装置，结果表明B通道和励磁变压器保护装置均工作正常，重新开机，B通道也能正常带负荷运行。但发现当发电机空载时

13、，进行A通道和B通道切换，发电机定子电压无扰动；当发电机负载时，进行A通道和B通道切换，发电机定子电压有明显的偏移，遂将事故原因分析重点放在A通道和B通道参数差异上，比较发现：A通道无功调差系数为0，B通道无功调差系数误设置为-15%。 无功调差系数的定义为发电机无功功率为额定容量时，叠加在电压测量值的发电机定子电压的百分数。无功功率调差系数为-15%的含义为当发电机无功功率为额定容量时，发电机定子电压测量等效降低-15%，即相当于增加励磁电流直至发电机定子电压增加15%，事故发生时，无功功率（100MVar）近似为额定容量（235MVA）的42.5%，由于A通道无功功率调差系数为0，B通道无

14、功功率调差系数为-15%，当励磁从A通道运行切换至B通道运行时，相当于发电机电压要增加6.37%，励磁电流急剧增加，超过励磁变压器保护启动值，延时后动作跳闸，发电机解列灭磁。 （3） 事故处理： 重新设置无功功率调差系数，A通道和B通道定值相同，发电机并网后重新做A通道和B通道切换试验，试验顺利完成，发电机定子电压、无功功率和励磁电流无明显变化。 检查励磁调节器励磁电流过励限制定值和励磁变压器保护装置定值配合情况，保证出现误强励时，励磁调节器励磁电流过励限制先动作降低励磁电流，不能出现励磁变压器保护先动作于发电机解列。4. 近端负荷设置负调差引起发电机无功波动故障分析（1）故障现象：某大型国企

15、自备电厂60MW机组，原励磁系统为老式模拟式励磁调节器，利用检修期间更换为微机型励磁调节器，励磁调节器调试完成后，发电机进行并网试验，试验期间发电机无功功率运行稳定，数天后，发电机重新开机后，发电机机端电压和无功功率出现长期不平息的波动现象。 （2）故障分析： 故障发生后，电厂和厂家技术人员对故障进行技术分析，对试验期间的录波数据和故障时的录波数据进行对比分析，结果显示前后的不同：试验期间发电机的负荷主要输出至高压母线（35KV），再经由高压母线（35KV）供给企业使用；而故障时发电机的负荷主要供给低压母线（6.3KV）使用。重新对定值进行核算，无功调差系数设置为-4%，由于发电机主接线采用单

16、元接线，因此调试人员根据励磁标准中无功功率调差设定的建议，选择无功调差系数为-4%，但是忽略低压母线负荷的作用，对于母线负荷而言，发电机定子与负荷之间阻抗为零，根据无功功率调差系数的物理意义，对于机端负荷较重的发电机组，其无功功率调差系数必须为正。 （3）故障处理：将无功功率调差系数更改为4%后，发电机无功功率波动很快平息后，运行稳定。Stanford generator repair and maintenanceStanford generators Profile,Cummins Generator Technologies (China) Co., Ltd. (Wuxi new era

17、 alternator Co., Ltd.) Cummins Generator Technologies in China, the only wholly-owned enterprises, the initial investment of $ 17.6 million. Was established in February 1996, was officially opened in November 1997. The current annual production capacity of 65,000 generators.Cummins Generator Technol

18、ogies has more than 50 years to meet the customer experience, the pilot of the AC generators technology, Cummins Generator Technologies has a global sales and service network, and production in the United Kingdom, the United States, China, India factory. The Wuxi plant is in full accordance with the

19、 design and technology of the Cummins Generator Technologies produces STAMFORD AC generators. Direct control of product design, materials, production, testing by the British officers. Small size, light weight, advanced technology, reliable performance, the important features of STAMFORD generators.C

20、ummins Generator Technologies STAMFORD generators with all the world diesel engine facilities, such as Cummins, Perkins, Volvo, MTU, and Deutz, Caterpillar and domestic 95,130,135,150,190 series such as diesel. Successful range of products supply generator sets manufacturers, widely used in the fiel

21、d of railways, shipping, postal and telecommunications, military, oil, transportation, high-rise buildings and cold storage containers, etc.Generator series produced by Cummins Generator Technologies: BC16, BC18, UC224, UC274, HC4, HC5, LV6, HC7. Power range: 6.5KW-2000KW. HC series generator Brushl

22、ess rotating magnetic field structure, the voltage is up to 660V/50HZ or 60HZ, meet the third part of the BS5000 standard and other international standards. HC4, HC5, HC6/LV6, HC7 four frame sizes, 200KW-2000 KW range, optional 1500rpm (50Hz) or 1800rpm (60HZ), 4-pole generator. 224KW-1300KW within

23、HC6/LV6 and HC7 two, frame size, optional 1000rpm (50Hz) or 1200rpm (60HZ), 6-pole generator. Frame sizes HC4 and HC5 generators, excitation system to use AS440 or SX421AVR of the stator supply or MX341 or MX321AVR permanent magnet generator (PMG) excitation, machine seat number HC6/LV6 and HC7 gene

24、rator MX341 or MX321AVR of permanent magnet generator (PMG) excitation system.Self-stimulation generator AVR control, host stator magnetic field of the exciter by AS440 (or SX421) AVR excitation source, the AVR is adjust the exciter field excitation current control device. AVR voltage sensing signal

25、 from the host of the stator windings to provide feedback, to achieve the control requirements of the host field current by controlling the low power exciter magnetic field to adjust the rectifier output power of the exciter armature. AS440AVR by induction two-phase average voltage, to ensure that h

26、igh voltage regulation, In addition, it is to monitor the engine speed is lower than the pre-selected speed (Hz) setting, the corresponding lower output voltage to prevent low engine speeds national strength, and mitigation of the impact load, in order to reduce the burden on the engine. In addition

27、 to the characteristics of the AS440, the SX421 also has a three-phase rms sensing characteristics (installed in the switch board) when used in conjunction with an external circuit breaker, it also provides over-voltage protection.Permanent magnet generator (PMG) excitation generator MX341 (or 321)

28、the AVR-exciter provides excitation source, the AVR is to adjust the exciter excitation current control device. If MX321AVR through an isolation transformer to the voltage sense signal from the host of the stator windings feedback control low power exciter magnetic field, adjusting the rectifier out

29、put power of the exciter armature, so as to achieve the control requirements of the host field current. PMG system provides a constant excitation power has nothing to do with the stator load, higher motor starting affordability is not subject to the nonlinear load (such as SCR DC motor) host stator

30、output voltage waveform distortion interference. MX341AVR to ensure that the adjustment rate of the higher voltage by detecting the two-phase average voltage, the other also detects the engine speed is lower than the pre-selected speed setting, the output voltage is reduced accordingly, to prevent o

31、verexcitation low engine speeds, and mitigation plus set out the time of impact, in order to reduce the burden on the engine. It also provides a delay overexcitation protection, de-excitation of the generator exciter field voltage is too high. In addition to providing the outside of the the MX341 gi

32、ant protection of the Friends of the engine minus Haute, the MX321, but also has the characteristics of three-phase rms detection and overvoltage protection.STAMFORD generator is equipped with carefully selected components, the use of the advanced world-class manufacturing process made in accordance

33、 with the highest international quality standards. Can adapt to the harsh environment of the whole class H insulation winding design and the best efficiency, especially for special occasions, standard 12 reconnection outlet header to ensure that meet various voltage requirements. International brand

34、s, user-friendly design and world-class services STAMFORD many lifelong customers, and broad areas of application.Typical accident analysis of the generator excitation systemA protection device false positives rotor circuit point grounding Troubleshooting(1) Fault phenomenon:Excitation excitation re

35、gulator, the generator terminal voltage gradually establish a stabilized value after a transition process, the rotor circuit of the protection device one point grounding fault, the generator is operating normally.Rotor voltmeter by measuring the generator rotor positive and negative ground voltage,

36、the bipolar-to-ground voltage is not zero, indicating that the generator rotor is not a little ground fault occurs. Press the reset button of the protection device, the rotor circuit point grounding fault signal disappears.(2) failure analysis:Analysis of protection device rotor circuit point ground

37、ing the action principle to know to determine the rotor ground fault protection device according to the rotor voltage. Issued early Reed Excitation Equipment excitation power input command rotor voltage increases, the generator voltage rises, after a time delay, the excitation regulator device autom

38、atically exit early shunt power due to the excitation regulator machine terminal voltage initial machine terminal voltage reference value is lower than the early shunt power generated, so the original after the exit of the shunt power, the rotor voltage suddenly dropped a lot, and then the rotor vol

39、tage feedback protection, the protection device that is the rotor circuit short-circuit resulting in a sudden drop in the rotor voltage , so to protect the reported signal. Excitation regulator inverter again after the de-excitation experiments, the excitation of the excitation regulator, manually i

40、ncrease the excitation regulator voltage reference value, to ensure that the generator terminal voltage is greater than the early shunt power generated, and re-excitation boost generator is operating normally, the protection device is not made to the rotor circuit point grounding fault alarm.(3) fai

41、lure treatment:The accident show that the protective devices, point grounding of the rotor circuit function is not perfect the mechanism of its action is not scientific enough, easy to malfunction, it is recommended to improve the function of the rotor circuit point grounding, or replacement for the

42、 more reliable the rotor circuit point grounding protection devices.In the rotor circuit point grounding protection feature is not perfect, the initial reference value adjustment Excitation Equipment excitation voltage initial reference value is greater than the early shunt power generated by the ge

43、nerator terminal voltage.2 adjust the active power caused the unit running out of the deal with the accident(1) accident phenomenon:The normal operation of a power plant generating units, the requirements l load operation, according to the tone, increase the active power, reactive power of the gener

44、ator output by 50MVar suddenly reduced to-80Mvar Excitation Equipment issued to the low excitation limit signal transformer group protection devices reported missing magnetic protection action, generator column solution, the excitation switch tripping.(2) Accident analysis:After the accident, checki

45、ng all the protection and abnormal signal transformer unit protection devices in addition to loss of excitation protection action any other accident alarm, fault recorder revealed that the failure occurs, the generator terminal voltage drops, reactive power into In to 80Mvar loss of field protection

46、 of the right action;Excitation Equipment In addition to the issue of the low excitation limit signal no other incident alarm signal Excitation Equipment recorded wave analysis shows that the excitation regulator device of power system stabilizer output sags to the lower limit of the amplitude (5% o

47、f the rated terminal voltage) generator The sharp decline in reactive phase advance is running low excitation limit the start of the excitation regulator device, but not enough time to adjust the generator into the depth to meet the operating conditions of loss of excitation protection.Was the only

48、active power to increase the operation, the generator excitation regulator PSS-1A power system stabilizer, so analysts believe that the accident is caused because the PSS anti tune. PSS-1A power system stabilizer, PSS itself unable to determine the generator active power increase is caused by the lo

49、w frequency oscillation caused by or motivated by the original regulation, when the prime mover to increase the active power output, the PSS output will reduce the power generation excitation current, thereby reducing the generator reactive power, which is the PSS-1A-type anti-tune phenomenon. PSS-1A generator excitation current is adjusted