低电压穿越版PPT学习教案

1、会计学1低电压穿越版低电压穿越版2004-12-1422009.01.06中国电力科学研究院新能源研究所第1页/共68页4.风电机组低电压穿越的实现方案Realization of wind turbine LVRT第2页/共68页第3页/共68页l什么是低电压穿越？LVRT：Low Voltage Ride Through当电网故障或扰动引起风电场并网点的电压跌落时，在一定电压跌落的范围内，风电机组能够不间断并网运行。 Wind turbines should stay connected to the network and keep operation following voltage

2、 dips caused by short-circuit on any or all phases, where the voltage measured at the HV terminals of the grid connected transformer remains above the predefined voltage profile.也有故障穿越的提法。FRT：Fault Ride Through第4页/共68页l由于风电机组一般采用异步发电机技术（丹麦概念），电网发生故障时机端电压难以建立，若风电机组继续挂网运行，将会影响到电网电压无法恢复，因此，电网发生故障出现电压跌落

3、时，一般都是采取切除风电机组的方法来处理。 Induction machine is usally used in Denmark Concept Wind Turbines, the active exciting can not be provided by. The voltage can not be recovered if the wind turbine still keep operating so the wind turbine must be tripped in case of voltage dips during the grid fault. 第5页/共68页 0

4、123456780 .9 81 .0 01 .0 21 .0 41 .0 61 .0 8t/sPM-1 .0-0 .50 .00 .51 .00 .20 .40 .60 .81 .0U-1 5 0-7 507 51 5 0Q/MVar1 .01 .11 .21 .3-1 0 001 0 02 0 0rPE/MWv150MW风电场，基于普通异步发电机的恒速风电机组。v三 相短路故障持续 0.1svWi n d f a r m c a p a c i t y 150MW. IG based wind turbines.v3 phase short-circuit duration 100ms动态电

5、压崩溃Dynamic Voltage Callapse 第6页/共68页l风电装机比例较低时：可以允许风电场在电网发生故障及扰动时切除，不会引起严重后果。lThe wind penetration is lowThe trip of wind farm (wind trubine) during power grid disturbances can be acceptable. Its not a big problem to the power system.第7页/共68页l风电装机比例较高时：高风速期间，由于输电网故障引起的大量风电切除会导致系统潮流的大幅变化甚至可能引起大面积的停电，

6、而带来频率的稳定问题。低电压穿越能力是必需的lThe wind penetration is highLarge scale wind farm ( wind turbine ) tripping will cause load flow changing violently even power system blackout. The frequecy stability issue is the most concern because the power losses could lead to instability. LVRT is necessary.第8页/共68页l高风电穿透

7、功率情况下，故障导致的电压跌落更为严重。Voltage dips will be more severe during high wind penetration风电机组额定运行时High Wind风电机组达到切入风速时Low Wind 第9页/共68页2008 BaiCheng Power Grid Single Line Diagram第10页/共68页2004-12-14121.00.80.60.40.20.0s1.150.920.690.460.230.00长岭220: 电压(pu)洮南220: 电压(pu)前郭220: 电压(pu)松原220: 电压(pu)长山厂220: 电压(pu

8、)DIgSILENT电网故障电压跌落曲线Voltage dips under power system disturbances第11页/共68页l系统中某节点电压跌落的严重程度与此节点距离故障点的电气距离远近此节点固有的无功电压支撑能力风电功率的高低 密切相关lThe voltage dip extent of specific busbar have closely related withElectrical distance to the fault locationVoltage support capability of the specific busbarWind Power

9、output 第12页/共68页l电网发生电压跌落对风电机组的影响机械、电气功率的不平衡影响机组稳定运行暂态过程导致发电机中出现过流，可能损坏器件附加的转矩、应力可能损坏机械部分lThe impact on wind turbine of voltage dipsUnbanlance torque may influnce the stable operation of wind turbineOvercurrent of generator in transient may damage the Electronics components.Additional torque or forc

10、es may damage the mechanical components.第13页/共68页l不同电网中对风电机组低电压穿越能力要求的高低也不太一样。lThe Low Voltage Ride Through Requirements to the wind turbines may different in different power grid.第14页/共68页2. 风电机组低电压穿越的必要性 The necessity of wind turbines LVRT第15页/共68页2.风电机组低电压穿越的必要性The necessity of wind turbines LVRT

11、l目前我国两大类风电机组的特性对比：Characteristics comparison of the normal two types of wind turbines第16页/共68页2.风电机组低电压穿越的必要性The necessity of wind turbines LVRTl目前我国两大类风电机组的特性对比： Current status of characteristics comparison of the normal two types of wind turbines稳态特性：变速风电机组好于恒速风电机组Steady State Characteristics: Var

12、iable speed better than Fixed speed 暂态特性：恒速风电机组好于变速风电机组由于变速风电机组转子变频器过流能力差，又无法实现低电压穿越能力。Transient State Characteristics: Fixed speed better than Variable speedReason: over-current capability of converter is limited, LVRT cant be realized at present. 第17页/共68页l基于普通异步发电机的恒速风电机组，由于电压问题无法完成低电压穿越（电网大扰动时）。

13、lFix speed wind turbine equipped with normal induction generator cant realize the Low Voltage Ride Through Capability because the generator terminal voltage can not be recovered after the large disturbances of the power grid (Short-circuit).2.风电机组低电压穿越的必要性The necessity of wind turbines LVRT第18页/共68页

14、l基于双馈电机的变速风电机组，是否能够实现LVRT？变速风电机组的LVRT功能，受制于电力电子器件自身的过流能力。一般而言，IGBT的过流能力只是额定电流的两倍。现有国产风电机组配备有被动Crow-bar，无法实现LVRT。lIf the LVRT can be realized by the variable speed wind turbine based on DFIG?The LVRT capability of variable speed wind turbine is limited by the over-current capability of the Converter

15、(23 times of rated current) Localized product wind turbines only equipped with passive crow-bar, LVRT cant be realized at present.2.风电机组低电压穿越的必要性The necessity of wind turbines LVRT第19页/共68页第20页/共68页第21页/共68页Pro-Fault 故障前223MW232kV234kV38Mvar 电容器组55MW时间: 05:07230kV第22页/共68页Post-Fault故障后0MW244kV251kV3

16、8Mvar 电容器组0MW时间: 05:07236kV定速机组第23页/共68页系统调整后After regulation0MW235kV237kV38Mvar 电容器组0MW控制电压时间: 05:13第24页/共68页第25页/共68页第26页/共68页第27页/共68页-低电压穿越必不可少！其提出主要是基于有功平衡的考虑。Based on power balancing consideration, the LVRT requirement is put forward.2.风电机组低电压穿越的必要性The necessity of wind turbines LVRT第28页/共68页第

17、29页/共68页 美国风电场低电压穿越标准（也是AWEA的LVRT要求）LVRT requirement in United State grid code第30页/共68页1.风电场必须具有在电压跌至15%额定电压时能够维持并网运行625ms的低电压穿越能力；2.风电场电压在发生跌落后3s内能够恢复到额定电压的90时，风电场必须保持并网运行（任何时间，只要电压值不低于图中的电压曲线）。1.A wind generating plant must have low voltage ride-through capability down to 15 percent of the rated l

18、ine voltage for 0.625 seconds;2.A wind generating plant must be able to operate continuously at 90 percent of the rated line voltage, measured at the high voltage side of the wind plant substation transformer.第31页/共68页加拿大LVRT能力规定（Quebec）LVRT requirement in Canada grid code第32页/共68页第33页/共68页第34页/共68页

19、l2001年之前：德国电网上的风电机组在电网故障时都会切除。l2001年：简单的Fault ride through的要求，实现故障后有功支持。AGO 1 （Advanced Grid Option 1）Vestas解决方案：在定子回路接入电阻，150200ms，无功功率不控制lBefore 2001, wind turbine may trip during grid disturbances.lAt 2001:Simple Fault ride through for post-fault active power output.AGO 1 （Advanced Grid Option 1）

20、第35页/共68页l2003年之后：E.on提出更高要求，Voltage tolerance curve 要求无功电流贡献以控制电压。AGO 2 （Advanced Grid Option 2）风电场本身有无功支撑能力，利于恢复，能够支撑电压。lAfter 2003More requirements were asked by E.on. Reactive current is required to contribute for voltage controlAGO 2Wind farm reactive power capability is required to suppurt the

21、 voltage restore.第36页/共68页德国LVRT能力规定（高短路电流）LVRT requirement for High short-circuit current第37页/共68页德国LVRT能力规定（低短路电流）LVRT requirement for low short-circuit current第38页/共68页第39页/共68页nThe support of the network voltage must be provided within 20 ms after fault identification by providing reactive power

22、 at the generator terminals with a factor of 2% of the rated current per percent of the voltage drop. Switching back from voltage control to normal operation is possible after 3 seconds.第40页/共68页第41页/共68页3.4 丹麦低电压穿越要求 Eltra requirement in Denmark Grid Code 第42页/共68页丹麦LVRT能力规定 LVRT requirement in Den

23、mark Grid Code第43页/共68页rated power no later than 10 s. after the voltage is above 0.9 p.u again. 3.4 丹麦低电压穿越要求 Eltra requirement in Denmark Grid Code 第44页/共68页3.4 丹麦低电压穿越要求 Eltra requirement in Denmark Grid Code 第45页/共68页4、风电机组低电压穿越的实现方案 Realization of wind turbine LVRT第46页/共68页 l保 护 转子过流，保护变频器。（Cro

24、w-bar）降低机械转矩，保证机组稳定运行，不发生功率振荡。（桨距角控制）lProtectionConverter protection to avoid the damage caused by over-current. (Crow-bar)Decreasing the mechanical torque to stabilize the wind turbine operation. (Pitch Control)第47页/共68页 l支 撑动态发出无功功率，支撑电网电压。（动态无功）尽快恢复电气有功出力。（有功控制）lSupportReactive power control to s

25、upport the grid voltage (Dynamic reactive power contribution)Active power control to restore the power output (Active power control) 第48页/共68页 1. 双馈变速机组的Crow-bar resistance 解决方案只是旁路转子变流器，定子侧变流器仍挂网运行。Crow-bar 动作期间，成为普通的异步机。lCrow-bar resistance solution of DFIG based wind turbinesBypass the rotor side

26、 converter, grid side converter still in operation.Behaving as the normal induction machine during the activation of Crow-bar.第49页/共68页 1. 双馈变速机组的Crow-bar resistance 解决方案Crow-bar短接时间很短，6080ms；Crow-bar的电阻可以阻尼转子磁链，当转子磁链衰减后就可以退出，此时稳态短路电流已不是很大。Crow-bar退出后，变频器重新同步，控制能力恢复。lCrow-bar resistance solution of

27、DFIG based wind turbinesDuration of Crow-bar activation lasting 60-80ms. The resistance of crow-bar damping the rotor flux and crow-bar out of service when the rotor flux declines. After the crow-bar out of service, the converter will be re-synchronous and restoring the controllability. 第50页/共68页 双馈

28、机转子短路器(Crow-bar)转子侧变频器典型Crow-bar控制电路 Typical Crow-bar control circuitDFIGRotor SideConverter第51页/共68页 2. 双馈变速机组的Fast Reconnection 解决方案Nordex 的双馈变速风电机组采用此种方案也采用 Crow-bar保护，但是Crow-bar可以做得较小。lFast Reconnection solution of DFIG based wind turbinesNordex solution for LVRTCrow-bar protection also used but

29、 with smaller capacity.第52页/共68页 2. 双馈变速机组的Fast Reconnection 解决方案100ms内切除风电机组，Crow-bar也动作。 100ms后，风电机组再次并网，同时Crow-bar退出，风电机组重新运行。lFast Reconnection solution of DFIG based wind turbinesCut off the wind turbine in 100ms with crow-bar activation.Reconnected the wind turbine 100ms later, deactivate the

30、crow-bar and re-operate the wind turbine.第53页/共68页 3. 双馈变速机组的Chopper Resistance 解决方案VESTAS机组采用此种方案采用大容量二极管与标准IGBT并联。lChopper Resistance solution of DFIG based wind turbinesBe adopted by Vestas wind turbinesLarge capacity diode paralleling with the standard IGBT第54页/共68页 3. 双馈变速机组的Chopper Resistance

31、解决方案 Chopper Resistance solution of DFIG based wind turbinesVa cUACVd c第55页/共68页 3. 双馈变速机组的Chopper Resistance 解决方案故障过程中，IGBT闭锁，二极管导通，短路引起的冲击电流经二极管流过，用二极管导通大的暂态过电流以保护IGBT。导致DC-Link的电容电压升高，采用chopper resistance，消耗电容的充电功率。lChopper Resistance solution of DFIG based wind turbinesThe impulsion current circ

32、ulating through the diode to protect the IGBT from damage during the fault. The voltage of DC-Link will be charged to a high level, the chopper resistance burning all the energy.第56页/共68页 此三种解决方案都会导致风电场在短时间内失去控制能力 Controllability will be lost during the LVRT function activated第57页/共68页l无电力电子设备，定、转子有

33、一定过流能力。l机端电压重建（Voltage Restore）与机组特性、电网坚强程度有关。lA certain over-current capability of the stator and rotor of normal induction generatorlTerminal voltage restore depends on the generator behavior as well as the strength of the power grid. 第58页/共68页 0123456780 .9 81 .0 01 .0 21 .0 41 .0 61 .0 8t/sPM-1

34、.0-0 .50 .00 .51 .00 .20 .40 .60 .81 .0U-1 5 0-7 507 51 5 0Q/MVar1 .01 .11 .21 .3-1 0 001 0 02 0 0rPE/MWv150MW风电场，基于普通异步发电机的恒速风电机组v三相短路故障 持续 0.1sv150MW wind farm based on fixed speed wind turbinev0.1s duration of 3 phased short circuit.动态电压崩溃Dynamic Voltage Collapse 第59页/共68页l对策：机械功率控制附加设备动态支撑电压（动态无

35、功补偿）Countermeasures Mechanical power control (By pitch control)Dynamic voltage support (By SVC or STATcom)第60页/共68页 01234567802 04 0t/sSVC Q/Mvar024681 0Ncap0 .40 .60 .81 .0U-1 5 0-7 507 51 5 0Q/MVar0 .9 51 .0 01 .0 51 .1 05 01 0 01 5 02 0 0rPE/MWvSVC能够提供动态无功支持v电磁功率快速增加，风电机组不超速，实现LVRT功能。vDynamic reactive power supported by SVC to recover the voltage and stabilize the wind turbine电压恢复较快Vo