104 lines
19 KiB
Markdown
104 lines
19 KiB
Markdown
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# Power production (DLC 1.1 to 1.5)
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In this design situation, a wind turbine is running and connected to the electric load. The assumed wind turbine configuration shall take into account rotor imbalance. The maximum mass and aerodynamic imbalances (e.g. blade pitch and twist deviations) specified for rotor
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manufacture shall be used in the design calculations. In addition, deviations from theoretical optimum operating situations such as yaw misalignment and control system tracking errors shall be taken into account in the analyses of operational loads.
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Design load cases (DLCs) 1.1 and 1.2 embody the requirements for loads resulting from atmospheric turbulence that occurs during normal operation of a wind turbine throughout its lifetime (NTM). DLC 1.3 embodies the requirements for ultimate loading resulting from extreme turbulence conditions. DLC 1.4 and 1.5 specify transient cases that have been selected as potentially critical events in the life of a wind turbine.
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The statistical analysis of DLC 1.1 simulation data, see 7.6.2.2 and Annex G, shall include at least the calculation of extreme values of the blade root in-plane moment and out-of-plane moment and tip deflection. If the extreme design values of the blade root moments derived from DLC 1.1 are exceeded by the extreme design values derived for DLC 1.3, the further analysis of DLC 1.1 may be omitted.
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If the extreme design values of the blade root moments derived from DLC 1.1 are not exceeded by the extreme design values derived for DLC 1.3, the factor c in Equation (20) for the extreme turbulence model used in DLC 1.3 may be increased until the extreme design values of the blade root moments computed in DLC 1.3 are equal to or exceed the relevant extremes. The characteristic values of the loads relevant for other turbine components may be determined from this analysis based on DLC 1.3 with the increased c value. As an alternative to this analysis, the appropriate characteristic values of all load components relevant for each specific turbine component may be directly determined or extrapolated from the simulation.
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在此设计工况下，一台风电机组正在运行并连接到电网负载。所假定的风电机组配置应考虑风轮不平衡。设计计算中应使用风轮制造中规定的最大质量和气动不平衡（例如叶片变桨角度和扭角偏差）。此外，在运行载荷分析中，应考虑偏离理论最佳运行工况的情况，例如偏航失准和控制系统跟踪误差。
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设计载荷工况 (DLC) 1.1 和 1.2 包含了风电机组在其整个寿命期内正常运行 (NTM) 期间发生的大气湍流引起的载荷要求。DLC 1.3 包含了极端湍流条件下引起的极限载荷要求。DLC 1.4 和 1.5 规定了被选为风电机组寿命期内潜在临界事件的瞬态工况。
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DLC 1.1 仿真数据的统计分析（参见 7.6.2.2 和附录 G）应至少包括叶根摆振力矩、挥舞力矩和叶尖变形的极值计算。如果 DLC 1.1 得出的叶根力矩极限设计值被 DLC 1.3 得出的极限设计值超过，则可以省略 DLC 1.1 的进一步分析。
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如果 DLC 1.1 得出的叶根力矩极限设计值未被 DLC 1.3 得出的极限设计值超过，则可以增加 DLC 1.3 中使用的极端湍流模型在公式 (20) 中的系数 c，直到 DLC 1.3 中计算的叶根力矩极限设计值等于或超过相关极值。与机组其他部件相关的载荷特征值可以根据增加 c 值的 DLC 1.3 的分析来确定。作为该分析的替代方案，与每个特定机组部件相关的所有载荷分量的适当特征值可以直接从仿真中确定或外推。
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# Start-up (DLC 3.1 to 3.3)
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This design situation includes all the events resulting in loads on a wind turbine during the transients from any standstill or idling situation to power production. The number of occurrences shall be estimated based on the control system behaviour.9
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For DLC 3.2, at least four different timing events between the EOG and the start-up event shall be considered for each wind speed. The first timing shall be chosen so that the beginning of the EOG occurs when the power production reaches 50 % of maximum power.
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The last timing shall be chosen so that the beginning of the EOG occurs when the power production reaches 95 % of maximum power. At least two additional timings shall be chosen, evenly distributed within the interval from 50 % to 95 % of maximum power.
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For each wind speed, the characteristic value of the load may be computed as the average value of the extreme computed transient value for the four defined distinct points of time.
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As an alternative to the EOG gust, the DLC 3.2 may instead be analysed using at least 12 stochastic wind simulations for each mean wind speed with the ETM. For each mean wind speed, a nominal extreme response is evaluated as the mean of the simulated extremes.
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这种设计情况包括在风电机组从任何停机或空转情况过渡到发电过程中，导致其承受载荷的所有事件。发生次数应根据控制系统行为进行估算。
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对于DLC 3.2，应针对每种风速考虑EOG和启动事件之间至少四种不同的时序事件。第一个时序应选择为EOG开始时，发电量达到最大功率的50%。
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最后一个时序应选择为EOG开始时，发电量达到最大功率的95%。应选择至少两个额外的时序，均匀分布在最大功率的50%到95%的区间内。
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对于每种风速，载荷的特征值可以计算为四个定义的独立时间点的极端计算瞬态值的平均值。
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作为EOG阵风的替代方案，DLC 3.2可以改为使用ETM对每种平均风速进行至少12次随机风模拟来分析。对于每种平均风速，标称极端响应被评估为模拟极值的平均值。
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# Normal shutdown (DLC 4.1 to 4.2)
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This design situation includes all the events resulting in loads on a wind turbine during normal transient situations from a power production situation to a standstill or idling condition. The number of occurrences shall be estimated based on the control system behaviour.10
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For DLC 4.2, the timing of the gust and the shutdown event shall be chosen such that the EOG gust starts at different times relative to the shutdown, with minimum six events evenly distributed from 10 s before the beginning of the shutdown, till the power reaches 50 % of the
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initial power production level.
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At least four evenly distributed rotor azimuth positions shall be applied for each distinct point of time. For each wind speed, the characteristic value of the load may be computed as the mean value of the extreme computed loads among all timings and azimuth positions considered.
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If, due to the safety and control system, a shutdown event is automatically triggered during the EOG gust, that event shall also be considered in the analysis.
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As an alternative to the EOG gust, the DLC 4.2 may instead be analysed using at least 12 stochastic wind simulations for each mean wind speed with the ETM. For each mean wind speed, a nominal extreme response is evaluated as the mean of simulated extremes.
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此设计工况包括风电机组在从发电工况到停机或怠速工况的正常瞬态过程中产生的所有载荷事件。事件发生次数应根据控制系统行为进行估算。10
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对于DLC 4.2，阵风和停机事件的发生时间应选择使得EOG阵风相对于停机在不同时间开始，至少有六个事件均匀分布在停机开始前10秒到功率达到初始发电水平的50%之间。
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对于每个不同的时间点，应至少应用四个均匀分布的风轮方位角位置。对于每个风速，载荷的特征值可以计算为所有考虑的时间点和方位角位置中计算的极端载荷的平均值。
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如果由于安全和控制系统，在EOG阵风期间自动触发了停机事件，则该事件也应在分析中予以考虑。
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作为EOG阵风的替代方案，DLC 4.2也可以使用ETM对每个平均风速进行至少12次随机风模拟进行分析。对于每个平均风速，名义极端响应被评估为模拟极端值的平均值。
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# Emergency stop (DLC 5.1)
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Loads arising from activation of the emergency stop button shall be considered.
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The azimuth position for the rotor at the time of a fault may have significant influence on the load level. The azimuth position at time of occurrence for the fault should be random.
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应考虑紧急停止按钮激活产生的载荷。
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故障发生时风轮的方位角位置可能对载荷水平有显著影响。故障发生时的方位角位置应是随机的。
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# Parked (standstill or idling) (DLC 6.1 to 6.4)
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In this design situation, the rotor of a parked wind turbine is either in a standstill or idling condition. In DLC 6.1, 6.2 and 6.3, this situation shall be considered with the extreme wind speed model (EWM). For DLC 6.4, the normal turbulence model (NTM) shall be considered.
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For design load cases, where the wind conditions are defined by EWM, either the steady extreme wind model or the turbulent extreme wind model may be used. If the turbulent extreme wind model is used, the response shall be estimated using either a full dynamic simulation or a quasi-steady analysis with appropriate corrections for gusts and dynamic response using the formulation in ISO 4354. If the steady extreme wind model is used, the effects of resonant response shall be estimated from the quasi-steady analysis above. If the ratio of resonant to background response (R/B) is less than 5 %, a static analysis using the steady extreme wind model may be used. If slippage in the wind turbine yaw system can occur at the characteristic load, the largest possible unfavourable slippage shall be added to the mean yaw misalignment. If the wind turbine has a yaw system where yaw movement is expected in the extreme wind situations (e.g. free yaw, passive yaw or semi-free yaw), the turbulent wind model shall be used and the yaw misalignment will be governed by the turbulent wind direction changes and the turbine yaw dynamic response. Also, if the wind turbine is subject to large yaw movements or change of equilibrium during a wind speed increase from normal operation to the extreme situation, this behaviour shall be included in the analysis.
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In DLC 6.1, for a wind turbine with an active yaw system, a yaw misalignment of up to ±15° using the steady extreme wind model or a mean yaw misalignment of ±8° using the turbulent extreme wind model shall be imposed, provided restraint against slippage in the yaw system
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can be assured.
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In DLC 6.2, a loss of the electrical power network at an early stage in a storm containing the extreme wind situation shall be assumed. Unless power back-up is provided for the control and yaw system with a capacity for yaw alignment for a period of at least 6 h, the effect of a
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wind direction change of up to ±180° shall be analysed.
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The partial safety factors for loads for DLC 6.1 and DLC 6.2 in Table 3 are derived by assuming that the coefficient of variation of the annual maximum wind speed is smaller than 15 %; for other COV, see footnote 31 in 11.3.2.
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In DLC 6.3, the extreme wind with a 1-year return period shall be combined with an extreme yaw misalignment. An extreme yaw misalignment of up to ±30° using the steady extreme wind model or a mean yaw misalignment of ±20° using the turbulent wind model shall be assumed.
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If for the cases DLC 6.1 with steady extreme wind model, DLC 6.2 and DLC 6.3, yaw misalignment is evaluated using discrete values, the increment in yaw misalignment shall be not more than 10° in the sector of the maximum lift force on the blades.
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In DLC 6.4, the expected number of hours of non-power production time at a fluctuating load appropriate for each wind speed where significant fatigue damage can occur to any components (e.g. from the weight of idling blades) shall be considered.
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在这种设计情况下，停泊的风电机组的风轮处于静止或空转状态。在DLC 6.1、6.2和6.3中，应采用极端风速模型（EWM）考虑这种情况。对于DLC 6.4，应考虑正常湍流模型（NTM）。
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对于设计载荷工况，当风况由EWM定义时，可以使用稳态极端风模型或湍流极端风模型。如果使用湍流极端风模型，则应使用完全动态仿真或准稳态分析来估算响应，并根据ISO 4354中的公式对阵风和动态响应进行适当修正。如果使用稳态极端风模型，则应根据上述准稳态分析估算共振响应的影响。如果共振响应与背景响应之比（R/B）小于5%，则可以使用稳态极端风模型进行静态分析。如果在特征载荷下风电机组偏航系统可能发生滑移，则应将最大可能的不利滑移添加到平均偏航失准中。如果风电机组的偏航系统在极端风况下预期会发生偏航运动（例如自由偏航、被动偏航或半自由偏航），则应使用湍流风模型，并且偏航失准将由湍流风向变化和机组偏航动态响应决定。此外，如果风电机组在风速从正常运行增加到极端情况期间发生大的偏航运动或平衡变化，则应将此行为纳入分析中。
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在DLC 6.1中，对于具有主动偏航系统的风电机组，如果能确保偏航系统防滑，则应施加使用稳态极端风模型的±15°偏航失准或使用湍流极端风模型的±8°平均偏航失准。
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在DLC 6.2中，应假定在包含极端风况的暴风雨早期阶段发生电网断电。除非为控制和偏航系统提供至少6小时偏航对准能力的备用电源，否则应分析高达±180°的风向变化的影响。
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表3中DLC 6.1和DLC 6.2的载荷分项安全系数是假设年最大风速变异系数小于15%而得出的；对于其他变异系数，请参见11.3.2中的脚注31。
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在DLC 6.3中，应将1年重现期的极端风与极端偏航失准相结合。应假定使用稳态极端风模型的±30°极端偏航失准或使用湍流风模型的±20°平均偏航失准。
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如果对于DLC 6.1（稳态极端风模型）、DLC 6.2和DLC 6.3工况，偏航失准是使用离散值评估的，则在叶片最大升力区域内，偏航失准的增量不应超过10°。
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在DLC 6.4中，应考虑在每个风速下，可能对任何部件造成显著疲劳损伤（例如，来自空转叶片的重量）的非发电时间的预期小时数。
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# Parked plus fault conditions (DLC 7.1)
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Deviations from the normal behaviour of a parked wind turbine, resulting from faults on the electrical network or in the wind turbine, shall require analysis. As a minimum, failures in the following systems shall be evaluated: brake system, pitch system, and yaw system. The fault
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condition shall be combined with EWM for a return period of one year. Those conditions shall be either turbulent or quasi-steady with correction for gusts and dynamic response.
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In case of a fault in the yaw system, yaw misalignment of ±180° shall be considered. If for the cases DLC 7.1 with fault in the yaw system, yaw misalignment is evaluated using discrete values, the increment in yaw misalignment shall be not more than 10° in the sector of the maximum lift force on the blades. For any other fault, yaw misalignment shall be consistent with DLC 6.1.
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If slippage in the yaw system can occur at the characteristic load found in DLC 7.1, the largest unfavourable slippage possible shall be considered.
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风电机组电气网络或风电机组故障导致停机风电机组偏离正常行为时，应进行分析。至少应评估以下系统的故障：制动系统、变桨系统和偏航系统。故障情况应与一年重现期的EWM相结合。这些情况应为湍流或准稳态，并对阵风和动态响应进行修正。
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如果偏航系统发生故障，应考虑±180°的偏航错位。如果对于偏航系统故障的DLC 7.1工况，使用离散值评估偏航错位，则在叶片最大升力区域，偏航错位的增量不应超过10°。对于任何其他故障，偏航错位应与DLC 6.1一致。
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如果在DLC 7.1中发现的特征载荷下偏航系统可能发生滑移，则应考虑最大的不利滑移。
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# Transport, assembly, maintenance and repair (DLC 8.1 and 8.2)
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For DLC 8.1, the manufacturer shall state all the wind conditions and design situations assumed for transport, assembly on site, maintenance and repair of a wind turbine. The maximum stated wind conditions shall be considered in the design if they can produce significant loading on the turbine. The manufacturer shall allow sufficient margin between the stated conditions and the wind conditions considered in design to give an acceptable safety level. Sufficient margin may be obtained by adding 5 m/s to the stated wind condition.
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In addition, DLC 8.2 shall include all transport, assembly, maintenance and repair turbine states which may persist for longer than one week. This shall, when relevant, include a partially completed tower, the tower standing without the nacelle and the turbine without one or more blades. In the case of a tower standing without a nacelle, appropriate means shall be taken to avoid critical wind speeds for vortex generated transverse vibrations, or the appropriate fatigue design load case shall be added11. It shall be assumed that the electrical network is not connected in any of these states. Measures may be taken to reduce the loads during any of these states as long as these measures do not require the electrical network connection.
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Blocking devices shall be able to sustain the loads arising from relevant situations in DLC 8.1. Non-redundant blocking devices shall be designed in component class 3. In particular, application of maximum design actuator forces shall be taken into account. It is recommended
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that standards for lifting appliances including safety factors/influence factors are additionally applied when relevant. Unless permanently installed, the lifting appliance itself is not covered by this document and should be designed and tested according to relevant standards for lifting appliances.
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对于DLC 8.1，制造商应说明风电机组运输、现场安装、维护和修理所假定的所有风况和设计工况。如果所说明的最大风况能对机组产生显著载荷，则应在设计中考虑。制造商应在所说明的工况与设计中考虑的风况之间留有足够的裕度，以提供可接受的安全水平。可以通过在所说明的风况上增加5米/秒来获得足够的裕度。
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此外，DLC 8.2应包括所有可能持续超过一周的运输、安装、维护和修理的机组状态。在相关时，这应包括部分完工的塔架、没有机舱的塔架以及缺少一个或多个叶片的机组。在塔架没有机舱的情况下，应采取适当措施以避免涡流引起的横向振动的临界风速，或应增加相应的疲劳设计载荷工况11。应假定在任何这些状态下，电网均未连接。只要这些措施不需要电网连接，就可以在任何这些状态下采取措施来降低载荷。
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锁定装置应能承受DLC 8.1中相关工况引起的载荷。非冗余锁定装置应按部件等级3进行设计。特别是，应考虑最大设计执行器力的施加。建议在相关时，额外应用包括安全系数/影响系数在内的起重设备标准。除非永久安装，起重设备本身不属于本文件范围，并应根据起重设备的相关标准进行设计和测试。
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