阅读说明：本技术 一种水电机组振动的反时限保护方法 (Inverse time limit protection method for vibration of hydroelectric generating set ) 是由 张飞 潘伟峰 江献玉 孙尔军 秦俊 邓磊 于 2020-02-14 设计创作，主要内容包括：本发明提供一种水电机组振动的反时限保护方法,包括：确定各个监测点启动振动保护的动作整定值,动作整定值同时适用于不同运行工况；获取运行状态下各个监测点的实时振动特征值；判断实时振动特征值是否连续在预设次数内大于振动启动量,当判断为是时,启动振动反时限保护,并计算实时振动特征值的累积值；比较累积值与预设数值,当累积值大于预设数值时,比较累积值与动作整定值,得到比较结果；根据比较结果对水电机组进行保护。通过将振动特征值与振动启动量比较,以及将大于振动启动量的情况下的累积值进行比较,两步比较相结合的方案,能够在工况频繁切换时提供有效保护,实现了对任意工况和任意工况切换过程中的振动保护。(The invention provides an inverse time limit protection method for vibration of a hydroelectric generating set, which comprises the following steps: determining an action setting value for starting vibration protection at each monitoring point, wherein the action setting value is simultaneously suitable for different operating conditions; acquiring real-time vibration characteristic values of each monitoring point in an operating state; judging whether the real-time vibration characteristic value is continuously greater than the vibration starting amount within preset times, starting vibration inverse time limit protection when the real-time vibration characteristic value is judged to be greater than the vibration starting amount, and calculating an accumulated value of the real-time vibration characteristic value; comparing the accumulated value with a preset value, and when the accumulated value is greater than the preset value, comparing the accumulated value with an action setting value to obtain a comparison result; and protecting the hydroelectric generating set according to the comparison result. Through comparing the vibration characteristic value with the vibration starting amount and comparing the accumulated value under the condition of being larger than the vibration starting amount, the scheme combining the two steps of comparison can provide effective protection when the working conditions are frequently switched, and the vibration protection in the switching process of any working condition and any working condition is realized.)

1. An inverse time limit protection method for vibration of a hydroelectric generating set is characterized by comprising the following steps:

determining an action setting value for starting vibration protection of each monitoring point, wherein the action setting value is simultaneously suitable for different operating conditions;

acquiring real-time vibration characteristic values of each monitoring point in an operating state;

judging whether the real-time vibration characteristic value is continuously greater than the vibration starting amount within preset times, starting vibration inverse time limit protection when the real-time vibration characteristic value is judged to be greater than the vibration starting amount, and calculating an accumulated value of the real-time vibration characteristic value;

comparing the accumulated value with a preset value, and when the accumulated value is larger than the preset value, comparing the accumulated value with an action setting value to obtain a comparison result;

and protecting the hydroelectric generating set according to the comparison result.

2. The inverse time-lag protection method for the vibration of the hydroelectric generating set according to claim 1, wherein the determining the action setting value for starting the vibration protection at each monitoring point comprises:

acquiring historical vibration characteristic values of the unit under different operating conditions, wherein the operating conditions comprise a stable operating process and a working condition conversion process;

respectively calculating integral constants of historical vibration characteristic values of all monitoring points according to the vibration starting amounts of different monitoring points to obtain integral constant arrays of all monitoring points;

respectively selecting an integral constant with the maximum value of each monitoring point;

and considering the reliability coefficient, and respectively calculating the action setting value of the vibration protection of each monitoring point.

3. The inverse time-lag protection method for vibration of a hydroelectric generating set according to claim 2, wherein the action setting value passes through S_i＝k·S_maxiCalculation of where S_iK is a reliability coefficient, S is an action setting value of each monitoring point_maxiThe maximum integral constant of the corresponding monitoring point is obtained, and the value of the reliability coefficient is 1.1-1.5.

4. Method for inverse time-lag protection of the vibrations of a hydroelectric generating set according to claim 2, characterized in that the integral constant of the vibration characteristic value is determined byCalculation of where S_a′_ctIs an integral constant of the vibration characteristic value, pu ═ V/V_actV is a historical vibration characteristic value, V_actAnd r is a constant for the vibration starting amount, and delta t is a time interval for calculating the real-time vibration characteristic value.

5. Method for inverse time-lag protection of the vibrations of a hydroelectric generating set according to claim 1, wherein said accumulated value is determined byWherein S is_actFor cumulative values of real-time vibration characteristics, pu₁Is the ratio of the real-time vibration characteristic value to the vibration starting amount, r is a constant, and delta t₁And the time interval of the real-time vibration characteristic value within the preset times is determined.

6. The method for inverse time-lag protection of vibration of a hydroelectric generating set according to claim 5, wherein the predetermined value is 0.

7. The method of claim 1, wherein protecting the hydro-power unit based on the comparison comprises:

when the accumulated value is greater than or equal to the action setting value, tripping the hydroelectric generating set vibration protection system;

and when the accumulated value is smaller than the action setting value, returning to obtain the real-time vibration characteristic value of each monitoring point in the running state.

8. The method for inverse time-lag protection of vibration of a hydroelectric generating set according to claim 1, wherein the predetermined number of times is two or more.

9. The method for inverse time-lag protection of vibration of a hydroelectric generating set according to claim 8, wherein the predetermined number of times is two.

10. The method for inverse time-lag protection of vibration of a hydroelectric generating set according to claim 1, wherein the vibration characteristic value comprises a peak-to-peak value of a vibration characteristic or a valid value of the vibration characteristic, and the calculation of the peak-to-peak value of the vibration characteristic comprises:

determining data to be calculated;

sorting the data to be calculated according to the numerical value;

determining a first numerical value corresponding to the upper quantile point and a second numerical value corresponding to the lower quantile point;

and calculating the difference value of the first value and the second value to obtain the peak-to-peak value.

Technical Field

The invention relates to the technical field of protection of hydroelectric generating sets, in particular to an inverse time limit protection method for vibration of a hydroelectric generating set.

Background

At present, China is the most abundant world hydropower resource country, and as late as 2018, the national hydroelectric machine capacity reaches 35226 ten thousand kilowatts, and the annual energy production is 12329 hundred million kilowatts, which respectively account for 18.5% and 17.6% of the national electric installed capacity and annual energy production. Along with the operation of large hydropower stations such as the three gorges, the Wudongde, the white crane beach and the like, the manufacturing technology of hydroelectric generating sets in China is gradually developed from technology following to technology leading. However, in the aspect of operation and maintenance technology of hydroelectric generating sets, China still has a large promotion space. Therefore, the research on the operation and maintenance technology of the reinforced hydroelectric generating set is the basis for ensuring the safe and stable operation of the generating set and a power grid, and is also an important strategic support for promoting new energy consumption and the like.

At present, in order to ensure the safe and stable operation of the hydroelectric generating set, a state maintenance technology enters a new development stage, the hydroelectric generating set is generally provided with a state monitoring system to monitor the parameters of the operation stability (vibration, swing, pressure pulsation and the like) of the hydroelectric generating set in real time, and whether the hydroelectric generating set is abnormal or not is judged by comparing the relation between a characteristic monitoring value and an alarm threshold value, so that measures are taken in time to avoid the 'faulty' operation of the hydroelectric generating set. However, the change of working conditions of the pumped storage unit is more frequent due to the fact that the hydro-power unit has different functions in the power system and different operation modes. Therefore, the existing vibration protection system generally depends on the actual operation working condition of the hydroelectric generating set, and can only provide abnormal protection for the vibration of the generating set under the stable operation working condition, so that the protection can not be realized on the working condition of the transition process, and great hidden danger is caused to the operation and maintenance of the generating set.

Disclosure of Invention

In view of this, the invention aims to provide an inverse time limit protection method for vibration of a hydroelectric generating set, so as to solve the problem that the existing protection method cannot accurately protect all working conditions.

Based on the purpose, the invention provides an inverse time limit protection method for the vibration of a hydroelectric generating set, which comprises the following steps:

determining an action setting value for starting vibration protection at each monitoring point, wherein the action setting value is simultaneously suitable for different operating conditions;

acquiring real-time vibration characteristic values of each monitoring point in an operating state;

judging whether the real-time vibration characteristic value is continuously greater than the vibration starting amount within preset times, starting vibration inverse time limit protection when the real-time vibration characteristic value is judged to be greater than the vibration starting amount, and calculating an accumulated value of the real-time vibration characteristic value;

comparing the accumulated value with a preset value, and when the accumulated value is larger than the preset value, comparing the accumulated value with an action setting value to obtain a comparison result;

and protecting the hydroelectric generating set according to the comparison result.

In one embodiment, the determining the action setting value for starting the vibration protection at each monitoring point includes:

acquiring historical vibration characteristic values of the unit under different operating conditions, wherein the operating conditions comprise a stable operating process and a working condition conversion process;

respectively calculating integral constants of historical vibration characteristic values of all monitoring points according to the vibration starting amounts of different monitoring points to obtain integral constant arrays of all monitoring points;

respectively selecting an integral constant with the maximum value of each monitoring point;

and considering the reliability coefficient, and respectively calculating the action setting value of the vibration protection of each monitoring point.

In one embodiment, the action setting value passes through S_i＝k·S_maxiCalculation of where S_iK is a reliability coefficient, S is an action setting value of each monitoring point_maxiThe maximum integral constant of the corresponding monitoring point is obtained, and the value of the reliability coefficient is 1.1-1.5.

In one embodiment, the integral constant of the vibration characteristic value is obtained byCalculating, wherein, S'_actIs an integral constant of the vibration characteristic value, pu ═ V/V_actV is a historical vibration characteristic value, V_actAnd r is a constant for the vibration starting amount, and delta t is a time interval for calculating the real-time vibration characteristic value.

In one embodiment, the accumulated value is calculated byWherein S is_actIs an accumulated value of the real-time vibration characteristic value, pu₁Is the ratio of the real-time vibration characteristic value to the vibration starting amount, r is a constant number, delta t₁And the time interval of the real-time vibration characteristic value within the preset times is determined.

In one embodiment, the preset value is 0.

In one embodiment, the protecting the hydroelectric generating set according to the comparison result includes:

when the accumulated value is greater than or equal to the action setting value, tripping the hydroelectric generating set vibration protection system;

and when the accumulated value is smaller than the action setting value, returning to obtain the real-time vibration characteristic value of each monitoring point in the running state.

In one embodiment, the preset number of times is two or more.

In one embodiment, the predetermined number of times is two.

In one embodiment, the vibration feature value includes a peak-to-peak value of the vibration feature or a valid value of the vibration feature, and the calculation of the peak-to-peak value of the vibration feature includes:

determining data to be calculated;

sorting the data to be calculated according to the numerical value;

determining a first numerical value corresponding to the upper quantile point and a second numerical value corresponding to the lower quantile point;

and calculating the difference value of the first value and the second value to obtain the peak-to-peak value.

From the above, the inverse time limit protection method provided by the invention determines the action setting values which can be suitable under different working conditions, obtains the vibration characteristic value in real time, starts the vibration inverse time limit protection after the vibration characteristic value is continuously greater than the vibration starting quantity for the preset times, and further carries out different protections on the hydroelectric generating set according to the relation between the accumulated value of the vibration characteristic value and the preset value and the action setting value. Therefore, the protection method of the invention can provide effective protection when the working conditions are frequently switched by comparing the vibration characteristic value with the vibration starting amount and comparing the accumulated value under the condition of being larger than the vibration starting amount, thereby realizing the vibration protection in any working conditions and any working condition switching process and improving the universality and the safety of the vibration protection method. The method has the advantages of simplicity, convenience, high reliability, good sensitivity and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without any creative effort.

FIG. 1 is a flow chart of an inverse time-lag protection method for vibration of a hydroelectric generating set according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of an inverse time-lag protection curve according to an embodiment of the present invention;

FIG. 3 is a flowchart illustrating the determination of the motion setting value for the vibration protection at each monitoring point according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating conventional calculation of peak-to-peak values for an embodiment of the present invention;

FIG. 5 is a schematic diagram of a bilateral quantile method for peak-to-peak value calculation according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a water diversion swing peak-to-peak characteristic of a unit under an example working condition according to an embodiment of the invention;

fig. 7 is a specific flowchart of an inverse time-lag protection method for vibration of a hydroelectric generating set according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.

It is to be noted that technical terms or scientific terms used in the embodiments of the present invention should have the ordinary meanings as understood by those having ordinary skill in the art to which the present disclosure belongs, unless otherwise defined. The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item preceding the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

The operation of the hydroelectric generating set has a typical intermittent working system characteristic, and the dispatching has an obvious periodic characteristic for controlling the operation of the hydroelectric generating set according to the operation condition of a power grid. This feature is mainly manifested in: the power generation is carried out in the peak load period (morning, afternoon and evening) of the power grid, the power generation is stopped in the valley load period (morning), and the water pumping and energy storage power station pumps water in the valley load period. The water pumping operation time is usually 6-8 hours, and the time of each power generation is 2-3 hours. Therefore, many hydroelectric generating sets have the characteristic of frequent start-stop, and after each start-up to the completion of load adjustment, the stabilization time of the peak value of the vibration peak is usually from half an hour to one hour. Taking a stable power generation working condition as an example, the stable working condition is defined as a state that the load of the unit is adjusted stably and the opening of the blade is basically constant. The stable working condition mainly refers to stable load, and parameters representing the states of the lubricating and cooling systems, such as the tile temperature, the oil temperature, the wind temperature, the water temperature and the like, are not necessarily stable. With a long-term operation of the unit, generally over an hour, the temperature parameters can reach a stability (one hour temperature difference change less than 2K). After the temperature parameter is stable, the vibration characteristic value also reaches a stable state, the vibration peak value and the time are approximately in an inverse time limit relation in the process, namely the vibration peak value is larger when the load adjustment is finished, and the vibration peak value is smaller and tends to be stable after the temperature of the lubricating and cooling medium is constant, the vibration peak value is in a convergence characteristic, which cannot be reflected by a threshold alarm strategy.

The inventor of the application finds that in the long-term vibration protection work, although the current vibration protection system realizes setting different alarm values aiming at different operation working conditions in the actual operation of the unit, the current vibration protection system is limited by the complexity of the operation working conditions, and the alarm threshold value is usually set into a plurality of numerical values according to the operation working conditions, so that the parameter setting of the vibration protection system is complex and unreliable. The alarm with the higher limit threshold value can only be effective under the stable operation working condition, and the actual operation of the unit is considered to be operated at different working condition points (different water heads and different loads), so that a plurality of power stations provide a vibration alarm strategy depending on the operation working condition points. This leads to complications in the alarm strategy. Simultaneously, the operating mode of unit switches comparatively frequently usually, if: for the peak-shaving frequency modulation unit, the load adjustment range is large, the frequency is started frequently, the unit working condition conversion process is frequent (from shutdown to power generation with load, from load to shutdown and the like), and the conversion frequency is more obvious in the pumped storage unit, so that the alarm is complex and the reliability is low under the working condition of the transition process.

The inventor of the application provides a method capable of effectively protecting both a stable operation working condition and a working condition in a transition process. The method protects the unit according to the accumulative quantity parameter of vibration, and the parameter is set according to the maximum accumulative quantity of unit vibration which possibly occurs under the condition of avoiding the normal operation of the unit. The method is simple, convenient and quick, can solve the problems of multi-parameter protection of the conventional hydroelectric generating set under different working conditions and protection loss under a transition working condition, has high reliability and good sensitivity, and can realize effective protection of the vibration of the hydroelectric generating set.

Referring to fig. 1, a method for inverse time-lag protection of vibration of a hydroelectric generating set according to an embodiment of the present invention includes:

s100, determining an action setting value for starting vibration protection of each monitoring point, wherein the action setting value is simultaneously suitable for different operation conditions;

s200, acquiring real-time vibration characteristic values of each monitoring point in an operating state;

s300, judging whether the real-time vibration characteristic value continuously exceeds the limit within the preset times, starting vibration inverse time limit protection when the real-time vibration characteristic value continuously exceeds the limit within the preset times, and calculating the accumulated value of the real-time vibration characteristic value;

s400, comparing the accumulated value with a preset value, and comparing the accumulated value with an action setting value to obtain a comparison result when the accumulated value is greater than the preset value;

and S500, protecting the hydroelectric generating set according to the comparison result.

The method comprises the steps of determining action setting values which can be suitable under different working conditions, obtaining a vibration characteristic value in real time, starting vibration inverse time limit protection after the vibration characteristic value is continuously greater than a vibration starting quantity for preset times, and further performing different protections on the hydroelectric generating set according to the relation between an accumulated value of the vibration characteristic value and a preset value and the action setting values. Therefore, the protection method of the invention can provide effective protection when the working conditions are frequently switched by comparing the vibration characteristic value with the vibration starting amount and comparing the accumulated value under the condition of being larger than the vibration starting amount, thereby realizing the vibration protection in the switching process of any working conditions and improving the universality and the safety of the vibration protection method. The method has the advantages of simplicity, convenience, high reliability, good sensitivity and the like.

In step S100, the action setting value is determined by inverse time limit protection. The concept of inverse time-lag protection is: when the protected equipment breaks down, the larger the fault current is, the smaller the delay of the relay protection equipment is. Namely: the action current is inversely proportional to the action time. A typical inverse time-lag protection curve is shown in fig. 2. Using current as an example, I in the figure_ophAnd I_oplRespectively representing a limited upper limit operating current and a limited lower limit starting current, t_upAnd t_sRespectively representing an upper limit action delay and a lower limit action delay.

Referring to fig. 3, the determining the action setting value for starting the vibration protection at each monitoring point includes:

s110, acquiring historical vibration characteristic values of the unit under different operation conditions, wherein the operation conditions comprise a stable operation process and a working condition conversion process;

s120, respectively calculating integral constants of vibration characteristic values of the monitoring points according to the vibration starting amounts of the different monitoring points to obtain integral constant arrays of the monitoring points;

s130, respectively selecting the maximum integral constant of each monitoring point;

and S140, considering the reliability coefficient, and calculating the action setting value of the vibration protection of each monitoring point.

In step S110, the different operation conditions include a static condition of the hydroelectric generating set, a no-load no-excitation variable-speed condition, a no-load rated speed variable-excitation condition, a generator grid-connected load condition or a generator grid-connected phase modulation operation condition, and the like. The vibration characteristic value is a normal value under different working conditions, and includes a peak value, a peak-peak value, an effective value, an average value, a fundamental wave amplitude, a 2-order harmonic amplitude or an 1/2-order harmonic amplitude of the vibration characteristic, and may be, for example, a speed effective value, a speed peak-peak value, a displacement peak-peak value, an acceleration peak-peak value, and the like.

Specifically, the peak-to-peak value is calculated as the difference between the maximum value and the minimum value in a group of statistical data, reflects the variation range of the data, and is calculated by a bilateral quantile method. The method comprises the following steps: determining data to be calculated; sorting the data to be calculated according to the numerical value; determining a first numerical value corresponding to the upper quantile point and a second numerical value corresponding to the lower quantile point; and calculating the difference value of the first value and the second value to obtain the peak-to-peak value.

By acquiring the stable operation working condition and the historical vibration characteristic value of the unit in the working condition conversion process, the normal data range of the vibration characteristic values of different monitoring points can be comprehensively and accurately acquired, and the reliability of the subsequent action setting value is improved.

In step S120, the vibration starting amount may be understood as a threshold value for starting vibration protection, and when the real-time vibration characteristic value is greater than the threshold value, the protection device is started, and the inverse time limit starts to time. The threshold value of the vibration protection starting can adopt a value recommended in national standards of a specific vibration characteristic value or a value recommended by a host design manufacturer. For example, reference may be made to the B/C boundary in appendix B of GB/T32584-2016, the C/D boundary in FIG. A1 of GB/T11348.5-2002, or a value recommended by the manufacturer of the host computer design for the vibration characteristic, i.e., the peak-to-peak value of vibration.

Integral constant passing formula of vibration characteristic valueAnd (4) calculating. In the formula, S'_actIs an integral constant of the vibration characteristic value. pu ═ V/V_actV is a historical vibration characteristic value, V_actIs the vibration start amount. r is a constant, and may be 0 to 2, and is used to characterize the inverse time-lag characteristics, such as conventional inverse time-lag characteristics (r ═ 0.02), very inverse time-lag characteristics (r ═ 1), and highly inverse time-lag characteristics (r ═ 2). Different characteristics are respectively suitable for different scenes, and a specific value of r is selected according to specific requirements in practical application. Δ t is a real-time vibration characteristic value calculation time interval.

In this step, the vibration characteristic value includes a plurality of stable operation conditions and a plurality of switching process values between the stable operation conditions, that is, the number of the operation conditions is the sum of the number of the stable operation conditions and the number of the operation condition switching processes. Therefore, the integral constant of the vibration characteristic value of each monitoring point is an integral constant array, and the integral constant number in the array is the sum of the stable working condition number and the working condition switching process number.

In step S130, the maximum integral constant of each monitoring point refers to selecting the integral constant with the largest value from the integral constant array as the maximum integral constant of the corresponding measuring point after all the working conditions are considered. Each monitoring point corresponds to a maximum integral constant.

In step S140, the operation setting value of vibration protection of each monitoring point is respectively represented by the formula S_i＝k·S_maxiCalculation of where S_iK is a reliability coefficient, S is an action setting value of each monitoring point_maxiIs the maximum integration constant for the corresponding monitoring point. The action setting value can avoid the maximum vibration accumulation amount which can occur under the normal operation working condition of the hydroelectric generating set, and can provide comprehensive protection for the switching process of the normal working condition and the working condition.

The value of the reliability coefficient is set empirically, and is preferably set to 1.1 to 1.5. The value of the reliability coefficient is set to be more than 1, so that the action setting value can be reliable to avoid the accumulation of vibration characteristic values calculated during the monitoring of normal working conditions (stable operation working conditions and normal working conditions conversion processes), the vibration protection misoperation and the vibration protection operation rejection can be balanced as much as possible, the relay which does not perform the action can be timely returned, and part of the system which normally operates is not cut off.

In step S200, the real-time vibration characteristic value may be detected by a device, such as a sensor, built in various state monitoring systems, monitoring and data acquisition systems, and the like. The specific method and apparatus for data acquisition are known and will not be described herein.

In step S300, the preset number of times may be two or more. The preset times is set to be two times or more than two times, so that the interference caused by the randomness of the out-of-limit vibration starting amount of the vibration characteristic value in the actual vibration characteristic value monitoring process can be reduced as much as possible, the misoperation of the protection device is avoided, the protection device can be accurately started, and the protection reliability is improved.

Preferably, the preset times are set to be two times, so that the sensitivity and the accuracy of the protection device are good.

The definition of inverse time-limit protection is the same as that in step S100, and is not described herein again.

The accumulated value of the real-time vibration characteristic value is represented by a formulaWherein S is_actFor cumulative values of real-time vibration characteristics, pu₁Is the ratio of the real-time vibration characteristic value to the vibration starting amount, r is a constant, and delta t₁And the time interval of the real-time vibration characteristic value within the preset times is determined.

It should be noted that, if it is determined that the real-time vibration characteristic value does not continuously exceed the preset number of times, the process returns to step S200 to continuously obtain the real-time vibration characteristic values of the monitoring points in the operating state.

In step S400, the preset value may be set to 0.

It should be noted that, when the accumulated value is smaller than the preset value, the protection is reset and the process returns to step S200. The specific meaning of the resetting protection is that the real-time vibration characteristic value is rapidly reduced and is restored to a normal level after the accumulated value is smaller than a preset numerical value.

And when the accumulated value is larger than the preset value, further comparing the accumulated value with the action setting value, and then performing the next protection operation according to the comparison result.

Through two comparisons, namely the comparison of the accumulated value with the preset value and the action setting value, the accumulated value is judged to be larger than the preset value, and then the next comparison is carried out, so that the interference caused by the vibration randomness can be better reduced, and the reliability and the accuracy of protection are improved.

In step S500, protecting the hydroelectric generating set according to the comparison result includes:

when the accumulated value is greater than or equal to the action setting value, tripping the hydroelectric generating set vibration protection system;

and when the accumulated value is smaller than the action setting value, returning to obtain the real-time vibration characteristic value of each monitoring point in the running state.

And if and only if the accumulated value is greater than or equal to the action setting value, the vibration protection system is tripped, so that the reliability and effectiveness of protection can be further improved, and the probability of misjudgment when the running state is unstable is reduced.

It should be noted that when the unit is in the operating state, there are cases where the cumulative value is greater than zero but the motion limit value cannot be reached for a long time. At this time, the vibration protection system is in a start-up state and can still stably operate, and this state can be called a critical state.

The method is characterized in that a swing signal (water guide swing) at the position of a water guide bearing is vibrated by a rotating component of a pumped storage power station, a vibration characteristic value, namely the water guide swing characteristic value, is taken as a peak value, M vibration measuring points of a unit are set, and one measuring point is the mth measuring point.

As shown in FIGS. 4 and 5, for the specific calculation of the peak-to-peak value, when the quantile is 2.5%, the specific calculation is as follows, ⑴ determining the data { x ] in the calculation period₁,x₂,…,x_n⑵ sequencing the data in time interval in turn (from big to small or from small to big) { y₁,y₂,…,y_n⑶ determining the corresponding values y of the upper quantile point and the lower quantile point_α/2、y_1-α/2⑷ calculating y_α/2-y_1-α/2The value of | is taken as the peak-to-peak value. The method adopts double-side quantile method to calculate, and can overcome the defect of inclusion in signalsEspecially impact noise, has excellent accuracy.

As shown in fig. 7, the action setting value determination includes: (1) and obtaining the vibration characteristics of the unit under different working conditions, wherein the vibration characteristics are water guide swing degree peak-to-peak values. The peak value of the water guide swing degree of a certain unit under the example working condition is shown in figure 6.

⑵ obtaining integral constant according to vibration threshold of different measuring points in the step, according to formulaDetermining integral value by first determining reference value V of pu value_actNamely the reference value of the peak value of the water deflection. V_actThis reference value may be defined by the boundary between B/C in appendix B of GB/T32584-.

According to FIG. 6, the peak value of the water swing conductivity at the initial stage of the power generation load process is more than 200 μm according to the formulaThe calculated integral constant value is positive, the integral constant value is gradually increased from the initial moment, and when the load is stable, the vibration value is far less than 200 μm, the integral constant value is reduced and rapidly becomes negative. According to the definition of the deadline in fig. 2, the protection means are activated only if the protection amount is greater than the activation amount, which means: the integration is performed when the peak to peak value of the water swing conductivity is greater than 200 μm. Logic to: when the power exponent in the formula is 0.5, namely r is 0.5, the integral value of the water guide swing degree peak value under the two working conditions of power generation load carrying working condition and water pumping phase modulation and water pumping is as follows: s_act1＝7.49、S_act29.58. According to a similar calculation mode, the integral value sequence of the peak value of the water-guide swing degree peak of a plurality of processes can be obtained and is S_m＝{S_act1，S_act1，...，S_actNWhere N is the number of transitions. In a similar manner to that described above,for M stations, M one-dimensional arrays can be obtained.

⑶, obtaining the maximum integral constant of the corresponding measuring point, obtaining a series of integral constant value arrays of each measuring point under different working conditions according to step ⑵ for different measuring points, wherein each measuring point corresponds to one integral constant value array, taking the maximum value in the array corresponding to each corresponding measuring point, the value being the maximum integral constant of the corresponding measuring point after all working conditions are considered, and taking max { S } for the water guiding swing degree example_mI.e. max S_act1，S_act1，...， S_actN}＝S_actxThe value S_actxNamely the maximum integral constant of the water guide swing degree. For M measuring points, the corresponding maximum integral constant { S }_max1，S_max2，...，S_maxM}。

⑷ obtaining different measuring point setting values by considering the reliability coefficient, considering certain reliability coefficient k (k)>1) S corresponding to each measuring point_maxiMultiplying by a reliability coefficient k to obtain a setting value S of a corresponding measuring point_i＝k·S_maxiThe value is the action setting value of the peak value of the corresponding measuring point water guide throw degree, and the value can avoid the maximum vibration accumulation amount which can occur under the normal operation condition of the hydroelectric generating set.

The monitoring and action flow is as follows:

(5) and the vibration monitoring system collects the water diversion swing peak-to-peak data in real time in the running state.

(6) And judging whether the vibration value exceeds the limit for two times continuously.

(7) Starting the vibration inverse time limit protection and calculating an accumulated value. In the step, when the peak value of the water guide swing degree peak of a certain measuring point continuously exceeds the limit twice, and once the protection device or the program is started, the protection device or the program is started according to a formulaThe accumulated value is calculated.

(8) Once the protection device or program is started, for exceeding the limit value V_actAfter the cumulative value is calculated, there will be a certain cumulative value calculation result when: resetting protection when the accumulated value is less than zero; the step means that the vibration is reduced quickly after exceeding the limitLow, return to normal level. And when the accumulated value is larger than zero and reaches an inverse time limit value, monitoring and vibrating the outlet trip of the protection system to complete the vibration protection function.

The inverse time limit protection method for the vibration of the hydroelectric generating set provided by the embodiment of the invention can be used for counting the historical vibration characteristic values of the vibration monitoring points of the hydroelectric generating set under different working conditions; obtaining the maximum integral constant and the action setting value of the corresponding monitoring point according to the historical vibration characteristic value; the method comprises the steps of starting a vibration protection device by monitoring whether a real-time vibration characteristic value exceeds a limit, calculating an accumulated value of the real-time vibration characteristic value, determining the flow direction of protection by comparing whether the accumulated value is greater than zero and whether the accumulated value is greater than a protection fixed value in real time, resetting a protection system when the accumulated value is less than zero, and protecting an outlet to act when the accumulated value is greater than zero and greater than an action set value so as to enable the outlet of the protection system to jump. When the running state that can effectively improve the frequent switching unit of operating mode is comparatively worsened, reliability and the validity of protection also can improve the reliability and the validity of protection when the operating mode is stabilized simultaneously.

The foregoing description has been directed to specific embodiments of this disclosure. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may also be possible or may be advantageous.

Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, is limited to these examples; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

While the present invention has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

The embodiments of the invention are intended to embrace all such alterations, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, substitutions, improvements and the like that may be made without departing from the spirit and principles of the invention are intended to be included within the scope of the invention.