• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    METHOD AND MODULE FOR MEASURING THE FREQUENCY CHANGE INDEX OF WAVE SHAPES RELATED TO THE AIR CONVERTER UNITS. Method and module for measuring the frequency change index of a waveform related to a wind turbine converter unit, which consists of; measure an instantaneous value of that frequency change index of the waveform, calculate a first filtering value of that frequency change index, having that first filtering value a good precision but a low temporal response, and calculate a second filtering value of that waveform index frequency change, having this second filtering value a good temporal response but little precision, compare this first and second filtering value and select that an output value of this measured change index is based on that first or second filtering value depending on this comparison.
    公开号:BR102013010981B1
    申请号:R102013010981-9
    申请日:2013-05-03
    公开日:2020-11-24
    发明作者:Francisco JIMENEZ BUENDIA
    申请人:Gamesa Innovation & Technology, S.L；
    IPC主号:
    专利说明:

    FIELD OF THE INVENTION
    [0001] The present invention refers to a method and a module for measuring the rate of change of frequency of waveforms related to the converter units, preferably the wind turbines. BACKGROUND OF THE INVENTION
    [0002] The controller modules and systems of the wind turbine converter units require precise operation that maintains a good temporal response.
    [0003] To measure the rate of change of frequency the previous documents on the subject describe the analog and digital measurement. US003032715 describes an analog frequency measurement by CCU with structural code. GB2159963 describes a measurement system based on the period counting of the voltage waveform used in the most advanced relays to measure the rate of frequency change.
    [0004] The use of relays to measure parameters related to frequencies is well known. In electrical systems, a rate of change relay detects zero crossings of a generator voltage. The following relay measures the time between crosses at zero and calculates a new frequency after each crossing at zero. If the frequency changes too much, the relay will trip. This method is, however, very sensitive to voltage waveform noise and usually requires several voltage waveforms in order to determine a measurement. In addition, the relays are Conceptually designed to detect vector changes instead of the rate of change of waveforms.
    [0005] Other known methods are based on frequency measurements. For example, US2007136Q13 describes several frequency measurements that allow the calculation of the finite derivative of these frequencies. This document describes a finite method with measurement points arranged in periods of half a cycle. With these measurements as inputs, the method subsequently determines the time derivative with two consecutive measurements remaining and dividing the result between half the period, or finally the inverse of the measured frequency value.
    [0006] Another method known in the art is to use the frequency measured by the converter unit using advanced phase capture loops (PLL). These phase capture loops calculate the angle and frequency of the voltage waveform with correct accuracy. Subsequently, the method of calculating the rate of change of frequency (ROCOF) will be based on the derivative of the frequency measurement from the PLL of the converter control unit. The mathematical considerations to extract these results are based mainly on two methods, either to calculate the derivative of the frequency values of the grid voltage through finite differences, or else to calculate the second derivative of the angle values of the network voltage using derivative functions.
    [0007] When measuring the rate of change (ROCOF) noise is a critical problem. This noise comes from the mains voltage and also from the mains voltage harmonics. In addition, the nature derived from ROCOF causes noise to amplify and even to make this critical problem worse.
    [0008] Thus, an objective of the present invention is to provide a method and measurement system that is stable and is not affected by noise. Within the scope of noise elimination strategies, another series of problems may arise, such as the discontinuity of the measured output waveforms. The wind turbine control units must measure the frequency and frequency rate of the variables, preferably the voltage waveforms of the wind turbine converter units. The operation of these controller units requires a quick time response, usually an interval of between 400 and 200 ms or even less. This is difficult to achieve if correct accuracy is required at the same time.
    [0009] In wind turbine systems there is an element of compensation between the precision and the temporal response of the ROCOF. These two requirements are generally contradictory because the increase in precision requires filtration, which also increases the temporal response.
    [00010] Thus, it is also another objective of the present invention to provide a method and measurement module that can be precise and that in turn has a rapid time response to control the converter unit of an wind turbine. SUMMARY OF THE INVENTION
    [00011] Some of the objectives and problems mentioned above are solved by a method and module according to the present invention. Concretely, the present invention describes a method to measure the rate of change of frequency of a waveform related to a converter unit of a wind turbine, that method comprises the consistent steps in the measurement of an instantaneous value of a frequency value in that way waveform related to that converter unit, the calculation of a first filtered value (ROCOF-F1) of that rate of change of frequency (ROCOF) based on this instantaneous frequency value, having that first filtered value (ROCOF-F1) an error of measurement less than a first predetermined measurement error (DB-ROCOF-F1), with that first filtered value (ROCOF-F1) having a slower time response than a predetermined time response requirement (t1), and the calculation of a second value filtered (ROCOF-F2) of this rate of change of frequency (ROCOF) based on this instantaneous frequency value, with this second filtered value (ROCOF-F1) a second measurement error (DB-ROCOF-F2) greater than this and first predetermined measurement error (DB-R0C0F-F1), with this second filtered value (ROCOF-F2) having a faster response time than this predetermined time response requirement (t1), and the calculation of a comparison value (Comp ) between this first filtered value (ROCOF-F1) and this second filtered value (ROCOF-F2), and the determination that an output value (ROCOF-CNT) of that measured rate of change is based on that first filtered value (ROCOF- F1) when that comparison value (Comp) remains below or becomes below a predetermined threshold level, and the determination that this output value (ROCOF-CNT) of this measured rate of change is based on that second filtered value ( R0C0F-F2) when this comparison value (Comp) becomes higher than this predetermined threshold level, where this predetermined threshold is determined according to this second predetermined measurement error (DB-ROCOF-F2).
    [00012] Preferably the step of calculating a comparison value (Comp) includes the calculation of the absolute value (Abs-Comp) of the difference between the first (ROCOF-F1) and second (ROCOF-F2) filtered value.
    [00013] Advantageously, the method determines that this output value (ROCOF-CNT) is zero when an absolute value of that first filtered value (ROCOF-F1) is less than that first predetermined measurement error (DB-ROCOF-F1), and determines that this output value (ROCOF-CNT) becomes the first filtered value (ROCOF-F1) when the absolute value of that first filtered value (ROCOF-F1) becomes greater than this first predetermined measurement error (DB-ROCOF- F1) while the absolute value (Abs-Comp) of this comparison is less than this predetermined threshold, and the method thus determines that this output value (ROCOF-CNT) becomes the second filtered value (ROCOF-F2) when this value absolute value (Abs-Comp) of this difference is higher than this predetermined threshold, and once the output value (ROCOF-CNT) has been converted into the second filtered value (ROCOF-F2), it is determined that this output value (ROCOF- CNT) is the first filtered value (ROCOF-F1) when that absolute value (Abs-Comp) of this difference becomes below this second predetermined threshold.
    [00014] The preferred values for the predetermined threshold are the second predetermined measurement error (DB-R0C0F-F2) of the second filter (F2), and could be specifically between 0.125 and 0.5 milliertz per second.
    [00015] On the other hand, this predetermined threshold could correspond to a hysteresis value (DB-ROCOF-D2-HYS) that is preferably twice the second predetermined measurement error (DB-ROCOF-D2).
    [00016] In addition, other desirable steps could include smoothing the measured output values (ROCOF-CNT) with a filtering function, it being preferable that the filtering function is a first order filtering function. Other measures include limitation measured output values (ROCOF-CNT) using a rate limiting block.
    [00017] Likewise, the calculation of the first (ROCOF-F1) and second (ROCOF-F2) filtered value is preferably carried out using an average calculation method or a transfer function. In particular, the averaging method is preferable for calculating the first (ROCOF-F1) filtered value.
    [00018] This method is preferably integrated into a controller unit of a wind turbine. Thus, the method also includes sending that output value (ROCOF-CNT) of that rate of change of frequency to a controller (CNT) of a wind turbine. , and the control of a converter unit (Converter) of a wind turbine.
    [00019] The present invention also describes a module for carrying out the measurement method. In general terms, this module consists of a circuit to measure an instantaneous value of the frequency of at least one waveform related to that converter unit, a first filter (F1) to calculate a first filtered value (ROCOF-F1) of that rate of change of frequency (ROCOF) based on this measured instantaneous frequency value, with that first filtered value (ROCOF-F1) having a measurement error lower than the first predetermined measurement error (DB-ROCOF-F1), having that first filtered value ( ROCOF-F1) a slower temporal response than a predetermined temporal response requirement (t1), and a second filter (F2) to calculate a second filtered value (ROCOF-F2) of that rate of change of frequency (ROCOF) based on that value of instantaneous frequency, having this second filtered value (ROCOF-F2) a second measurement error (DB-ROCOF-F2) higher than this first predetermined measurement error (DB-ROCOF-F1), having this second filtered value (ROCOF- F2) one time response faster than this predetermined time response requirement (t1), and a comparator to calculate a comparison value (Comp) between this first filtered value (ROCOF-F1) and this second filtered value (ROCOF-F2), and a value output of that rate of change (ROCOF-CNT) based on that first filtered value (ROCOF-F1) when that comparison value (Comp) remains below or becomes below a predetermined threshold level, and that output value of that rate of change (ROCOF-CNT) is based on this second filtered value (ROCOF-F2) when that comparison value (Comp) becomes higher than this predetermined threshold level, and this predetermined threshold is based on the second predetermined measurement error (DB -ROCOF-F2).
    [00020] Preferably this module includes means of calculation to determine the absolute value (Abs-Comp) of the difference between the first (ROCOF-F1) and the second (ROCOF-F2) filtered value. In addition, this module may include means for limit or smooth this output value (ROCOF-CNT), preferably a rigid limiter, a rate limiter and / or a first order filter. FIGURES
    [00021] Fig.1 presents a modality of a system in which the rate of change of frequency is integrated into a converter controller inside a wind turbine.
    [00022] Fig.2 presents a modality with a time diagram of waveforms corresponding to the first and second filtered values, the output values of the rate of change measurements, as well as the absolute value of their difference.
    [00023] Fig.3 presents a modality of the present invention with the preferred electronic circuit to measure the rate of change of frequency (ROCOF) of waveforms. DESCRIPTION OF PREFERENT MODES
    [00024] Figure 1 shows a converter controller for a converter unit of a wind turbine. The present invention relates to variable speed wind turbines that are connected to the grid and the effects of a grid frequency change. It is important to have a precise and quick measurement of the frequency and the rate of change of frequency of the grid voltage in order to adapt the operation of the wind turbine to the new condition of the grid.
    [00025] Normally wind turbine controllers need frequency and frequency rate measurements that show a quick time response, which is usually 200 ms or less. This quick response requirement is a demanding requirement for the unit of measurement included in the converter controller.
    [00026] A voltage waveform in the converter unit is the preferred variable to be measured. However, other variables based on intensity and / or other voltage and power parameters can be used.
    [00027] A preferable method for measuring the frequency of the mains voltage waveform is to use advanced phase capture loops, PLL, in the converter unit. These PLLs are used to calculate the angle and frequency of the voltage wave. A wind turbine controller will need a frequency measurement provided by the PLL. Before sending it, a first order filter is applied to minimize the peaks and other noise present in the network and / or the measuring equipment.
    [00028] Subsequently, it is possible to measure an instantaneous rate of change (ROCOF) depending on the derivative of the frequency measurement or any other suitable method. This derivative can be calculated preferably by means of finite differences in the frequency of mains voltage or by calculating second derivatives. However, as already explained, this instantaneous measure will not comply with the temporal response required by the controller.
    [00029] The present invention proposes the calculation of two filtered values of the required rate of change of frequency (ROCOF). A first filtered value (ROCOF-F1) uses a filtering function that has a measurement error less than the first measurement error predetermined (DB-ROCOF-F1), but at the same time it has a slower time response than a predetermined time response requirement (t1), which is usually in the range between 200 and 400 milliseconds. Therefore, this first filtered value has an improved accuracy but cannot be used if variations in the mains voltage frequency suddenly appear.
    [00030] To resolve this limitation, a second filtered value (ROCOF-F2) is used. Specifically, the second value is less accurate but can meet the time restriction requirement. The output variable of the ROCOF measurement is therefore selected between the first and second filtered values, usually according to precision requirements when the mains voltage variations are smaller. However, for larger variations the output value will change to the second filtered value (ROCOF-F1). In this way, the continuous operation of the wind turbine controller is guaranteed at all times.
    [00031] Both the first filtered value (ROCOF-F1) and the second filtered value (ROCOF-F2) can be calculated using averaging methods or transfer functions. The averaging method is preferable for the first filtered value due to its inherent high precision and low temporal response. This method is based on averaging the frequency over a period of time and calculating a rate of change (ROCOF) value as finite differences of two frequency values obtained in averaging.
    [00032] As an example, the method preferably calculates the frequency averages of the last ΔT1 milliseconds (for example the last 200 ms) and stores those averages, then, after ΔT2 (for example 1000 ms), the average of 200 ms calculated between t-ΔT2 and t-ΔT2- ΔT1 Average tea calculated between t and -T1 are used in the finite difference formula:
    where Δt2 must be Δt2> Δt1 since the derivative period must always be longer than the average to avoid erroneous calculations.
    [00033] This formula can be simplified and better understood when Δ'2 Δt1, the formula adopts the following form:

    [00034] As already mentioned, a transfer function can be used to model either of the two filters since the adjustment of the parameters can achieve good precision and a low rise time or, vice versa, a rise time low or poor accuracy and a shorter rise time.
    [00035] A preferred derivative transfer function has a second-order denominator so that its gain for the infinite signal frequency components is zero. This means that it inherently functions as a low-pass filter or attenuator, and therefore noise is not amplified. In turn, the system is stable. The transfer function can be expressed using the following equations:

    [00036] These forms are used as derivative low-pass filters, where G is the gain, Ç (geta) is a damping factor and ωn is the natural oscillation frequency.
    [00037] If the k values (the Ç and ωn for the corresponding equation) are adjusted, a different time response and noise errors can be obtained. The lower the temporal response, the greater the noise cancellation. It is preferable to adjust the k values to avoid system instability: the extra power is calculated according to the ROCOF measurements and this extra power also changes the frequency and ROCOF. This coupling can cause frequency instability if the k factors are not adjusted properly.
    [00038] Therefore, the transfer functions, compared with the use of averaging methods, are considered more stable in nature due to their low-noise filtering, in addition, this method is computationally effective because of storing a fewer variables in memory.
    [00039] To achieve a first filter transfer function (F1) for this first filtered value (ROCOF-F1), the preferred parameters include a low value of ωn and a high value of Ç.
    [00040] On the contrary, a second filtered value (ROCOF-F2) has a high value of ωn and a low value of Ç.
    [00041] Figure 2 shows the time evolution of several important variables to understand the invention. It is possible to observe that the first filtered value (ROCOF-F1) does not show ripples and has a smooth overall shape. Sudden changes in mains voltage will not be followed by intensity, regardless of the precise state of your final state.
    [00042] Rapid variations in this line voltage can be followed by the second filter (ROCOF-F2). The general shape of this curve shows the ripples of sudden variations. Its main drawback is its limited measurement accuracy.
    [00043] The upper curve in figure 2, marked Abs (ROCOF-F1 minus ROCOF-F2) shows the absolute value of these differences. The curve has three regions. A first section (21) of this curve occurs when the absolute value of the first filtered value is less than a measurement error (DB) of that first filter. DB is also called dead measurement band and should be greater than the precision (noise) of the first filter (F1). The output value of the rate of change of frequency (ROCOF) is then identified as zero. If | ROCOFFI | - DBROCOF_FI, then ROCOFCNT = 0
    [00044] A second section (22) is reached when a comparison value between the first and the second filtered value, preferably the absolute value of its difference, reaches a predetermined value or threshold level.
    [00045] This threshold is defined by the precision of the second filter (DB-R0C0F-F2) or a hysteresis value. The hysteresis value is usually twice the measurement error value of the second filter.
    [00046] Once the threshold is reached, the second filtered value (ROCOF-F2) is selected as the output value (ROCOF-CNT). If | ROCOFFI-ROCOFF2 | > DBRocoF_F2_hys, so ROCOFCNT = ROCOFF2
    [00047] This allows for a temporal response (t1) according to the requirements of the wind turbine controller, although to a certain extent waiving accuracy.
    [00048] The second section comes to an end once the calculated comparison value, that is, the preferable absolute value of the difference, gets to be less than the dead band of the second filter included in hysteresis. If ROCOFCNT = ROCOFF2 and | ROCOFFI - ROCOFF2 | <DBROCOF_F2, then ROCOFCNT = ROCOFFI
    [00049] Finally, the third section (23) of the curve generates the first filtered value (ROCOF-F1) again.
    [00050] Figure 3 shows a preferable electronic circuit for carrying out the method according to the present invention.
    [00051] A first step unit (31) carries out the measurement of the rate of change of frequency (ROCOF) of two steps, preferably by hysteresis, the inputs of that first unit (31) are the values of that first and second filtered value Its difference is calculated using analog or digital means, the output being an absolute value (Abs-Comp) of this comparison. This signal subsequently constitutes an entry to a next stage of comparators. These comparators have predetermined threshold values, these being the predetermined measurement error of the second filter (ROCOF-F2-DB), normally 0.125 mHz, and a related hysteresis value, normally 0.25 mHz. This hysteresis value is preferably set at twice the measurement error of the second filter. The output of these two comparators is processed logically, preferably through the logical operators AND and / or OR. These operators can, in turn, be implemented by means of sequential and / or feedback electrical or electronic architectures. In this way, a conditional selector is controlled. This selector preferably selects the first or second filtered value. This selection mainly consists of the direct values of the selected filter, but it can also have a multiplication factor, for example a constant, or any other suitable manipulation. This output can be the total output value, that is, the output value (ROCOF-CNT) that is sent to the wind turbine controller. However, other steps can be added to obtain a signal with less noise.
    [00052] Therefore, the output signal corresponding to the first stage unit (31) can be the input of an optional second stage unit (32). This unit (32) will consider the application of the first dead band (DB) of the first filter (F1). Again, its preferable implementation takes the form of an absolute value operator in combination with a comparator. The reference value of this comparator is the predetermined measurement error of that first filter. Its value is preferably 0.125 mHz or less. The output signal of the values below this measurement error will be considered zero.
    [00053] A third step (33) can be added as an option to consider the dead bank of the frequency change rate according to the frequency value. In Europe a nominal frequency of 50 Hz is used, while the values in the United States and other countries reach 60 Hz. Other values are possible depending on the nominal frequency of the system.
    [00054] A fourth optional step unit (34) is added as a rigid limiter and can be implemented under favorable conditions as a saturation filter. In addition, an optional fifth step (35) can also be added as a rate limiter to limit the rate of change of measures in the event of a sudden change between the first and second filtered values. Sudden changes to zero due to dead frequency bands and ROCOF will also be kept to a minimum.
    [00055] Finally, it is possible to add an optional sixth step (36) to smooth any transition, as with the rate limiter. This step can be implemented as a first order transfer function.
    [00056] Figures and embodiments are considered preferable examples for illustrative purposes. The invention is defined by the scope of the embodiments.
    权利要求:
    Claims (14)
    [0001]
    1. Method for measuring the rate of change of frequency (ROCOF-CNT) of a waveform related to a converter unit of a wind turbine, said method comprising the steps of -measuring an instantaneous frequency value of said waveform related to said converter unit, calculating a first filtered value (ROCOF-F1) of a rate of change of frequency (ROCOF) based on said instantaneous frequency value, said first filtered value (ROCOF-F1) having an error measurement less than a first predetermined measurement error (DB-ROCOF-F1), said first filtered value (ROCOF-F1) having a slower time response than a predetermined time response requirement (t1), characterized by the fact that the method further comprises the steps of calculating a second filtered value (ROCOF-F2) of said frequency change rate (ROCOF) based on said instantaneous frequency value, said second filtered value (ROCOF-F2) having a second error measurement (DB -ROCOF-F2) greater than said first predetermined measurement error (DB-ROCOF-F1), said second filtered value (ROCOF-F2) having a faster response time than said predetermined time response requirement (t1), and -calculate a comparison value (Comp) between said first filtered value (ROCOF-F1) and said second filtered value (ROCOF-F2), and -determine that an output value (ROCOF-CNT) of said measured rate of change is zero when said comparison value (Comp) is equal to a predetermined threshold level, and -determine that an output value (ROCOF-CNT) of the dictated rate of change is based on said first filtered value (ROCOF-F1 ) when said comparison value (Comp) remains below or becomes below a predetermined threshold level, and -determine that said output value (ROCOF-CNT) of said measured rate of change is based on said second value filtered (ROCOF-F2) when said comparison value (Comp) becomes higher than said li level predetermined miar, being that - the predetermined threshold is determined based on the said second predetermined measurement error (DB-ROCOF-F2).
    [0002]
    2. Method for measuring the rate of change of frequency (ROCOF-CNT) according to claim 1, characterized by the fact that the step of calculating a comparison value (Comp) includes calculating the absolute value (Abs-Comp) of the difference between the first (ROCOF-F1) and second (ROCOF-F2) filtered value.
    [0003]
    3. Method for measuring the rate of change of frequency (ROCOF-CNT) according to claim 2, characterized by the fact that the method comprises -determining that said output value (ROCOF-CNT) is zero when an absolute value of said first filtered value (ROCOF-F1) is less than said first predetermined measurement error (DB-ROCOF-F1), -determine that said output value (ROCOF-CNT) becomes the first filtered value (ROCOF-F1 ) when the absolute value of said first filtered value (ROCOF-FI) becomes greater than said first predetermined measurement error (DB-ROCOF-F1) while the absolute value (Abs-Comp) of said comparison is lower than said predetermined threshold , and -determine that said output value (ROCOF-CNT) becomes the second filtered value (ROCOF-F2) when said absolute value (Abs-Comp) of said difference is higher than said predetermined threshold, -after the output value (ROCOF-CNT) has become the second filtered value (ROCOF-F2), determine that said value Output value (ROCOF-CNT) is the first filtered value (ROCOF-F1) when said absolute value (Abs-Comp) of said difference becomes lower than said second predetermined threshold.
    [0004]
    4. Method for measuring the rate of change of frequency (ROCOF-CNT) according to any one of claims 1 to 3, characterized in that said predetermined threshold is the second predetermined measurement error (DB-ROCOF-F2) second filter (F2), preferably between 0.125 and 0.5 millihertz / s.
    [0005]
    5. Method for measuring the rate of change of frequency (ROCOF-CNT) according to any one of claims 1 to 4, characterized in that said predetermined threshold corresponds to a hysteresis value (DB-ROCOF-D2-HYS ), preferably being twice the second predetermined measurement error (DB-ROCOF-D2).
    [0006]
    6. Method for measuring the rate of change of frequency (ROCOF-CNT) according to claim 2, characterized by the fact that the method comprises smoothing measured output values (ROCOF-CNT) with a filtering function, preferably said filtering function being a first order filtering function.
    [0007]
    7. Method for measuring the rate of change of frequency (ROCOF-CNT) according to claim 2, characterized by the fact that the method comprises limiting measured output values (ROCOF-CNT) with a rate limiting block.
    [0008]
    8. Method for measuring the rate of change of frequency (ROCOF-CNT) according to claim 2, characterized by the fact that the method comprises calculating said first (ROCOF-F1) and second (ROCOF-F2) filtered value using at least one averaging method or a transfer function.
    [0009]
    9. Method for measuring the rate of change of frequency (ROCOF-CNT) according to claim 8, characterized by the fact that the method comprises calculating said first filtered value (ROCOF-F1) using an averaging method.
    [0010]
    10. Control method of a wind turbine converter unit, characterized by the fact that the method comprises the steps of -measuring the rate of change of frequency (ROCOF-CNT), as defined in claim 1, and -sending the said output value (ROCOF-CNT) of said rate of change of frequency to a controller (CNT) of a wind turbine, and -controlling a converter unit (Converter) of a wind turbine.
    [0011]
    11. Module for measuring the rate of change of frequency (ROCOF-CNT) of a waveform related to a converter unit of a wind turbine, the module comprising a circuit for measuring an instantaneous value of a frequency value of said form waveform related to said converter unit, -a first filter (F1) to calculate a first filtered value (ROCOF-F1) of said frequency change rate (ROCOF) based on said measured frequency value, said first value filtered (ROCOF-F1) having a measurement error less than a first predetermined measurement error (DB-ROCOF-F1), said first filtered value (ROCOF-F1) having a slower time response than a predetermined time response requirement (t1), characterized by the fact that the module also comprises -a second filter (F2) to calculate a second filtered value (ROCOF-F2) of said rate of change of frequency (ROCOF) based on said measured instantaneous frequency value, the said second val or filtered (ROCOF-F2) having a second measurement error (DB-ROCOF-F2) greater than said first predetermined measurement error (DB-ROCOF-F1), said second filtered value (ROCOF-F2) having a temporal response faster than said predetermined time response requirement (t1), and -a comparator to calculate a comparison value (Comp) between said first filtered value (ROCOF-F1) and said second filtered value (ROCOF-F2), whereby -an output value of said rate of change (ROCOF-CNT) is zero when said comparison value (Comp) is equal to a predetermined threshold level, and -an output value of said rate of change (ROCOF -CNT) is based on said first filtered value (ROCOF-F1) when said comparison value (Comp) remains lower or becomes below a predetermined threshold level, and -an output value of said rate of change ( ROCOF-CNT) is based on said second filtered value (ROCOF-F2) when said comparison value (Comp) becomes higher than the dit the predetermined threshold level, said predetermined threshold being based on the second predetermined measurement error (DB-ROCOF-F2).
    [0012]
    12. Module for measuring the rate of change of frequency (ROCOF-CNT) according to claim 11, characterized by the fact that said comparator includes means of calculation to determine the absolute value (Abs-Comp) of the difference between the first (ROCOF-F1) and second (ROCOF-F2) filtered value.
    [0013]
    13. Module for measuring the rate of change of frequency (ROCOF-CNT) according to claim 11, characterized by the fact that said module includes means to limit or smooth said output value (ROCOF-CNT).
    [0014]
    14. Module for measuring the rate of change of frequency (ROCOF-CNT) according to claim 13, characterized in that said means for limiting or smoothing are a rigid limiter, a rate limiter and / or a filter of first order
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    同族专利:
    公开号 | 公开日
    CN103383411A|2013-11-06|
    BR102013010981A2|2015-07-07|
    ES2428240B1|2015-03-10|
    EP2660613A1|2013-11-06|
    US20130341922A1|2013-12-26|
    CN103383411B|2018-08-03|
    ES2428240R1|2014-03-05|
    ES2705298T3|2019-03-22|
    ES2428240A2|2013-11-06|
    EP2660613B1|2018-07-04|
    DK2660613T3|2018-10-22|
    US9128133B2|2015-09-08|
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    法律状态:
    2015-07-07| B03A| Publication of a patent application or of a certificate of addition of invention [chapter 3.1 patent gazette]|
    2018-12-04| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-11-26| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2020-07-07| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2020-11-24| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 03/05/2013, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    ES201200454A|ES2428240B1|2012-05-03|2012-05-03|Method and Module to measure the frequency change rate of the waveforms related to the wind turbine converter units|
    ESP201200454|2012-05-03|
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