CN107797001B - Detection method, device and the wind power generating set of capacitive faults - Google Patents

Abstract

The invention provides a capacitor fault detection method, device and wind power generator set. The detection method includes: obtaining the initial equivalent series resistance of the support capacitor in the generator set and the working equivalent series resistance of the support capacitor after a preset time period. ; According to the initial equivalent series resistance and the working equivalent series resistance, determine whether the support capacitor fails. The capacitor fault detection method, device and wind power generator set provided by the present invention obtain the initial equivalent series resistance and working equivalent series resistance of the supporting capacitor in the generator set, and obtain the initial equivalent series resistance and the working equivalent series resistance according to the obtained initial equivalent series resistance and working equivalent series resistance. Connecting capacitors in series can accurately and effectively determine whether the support capacitors fail, effectively reducing labor costs and labor costs, and also improving the accuracy and reliability of support capacitor detection and judgment, ensuring the stable and reliable operation of the generator set. Therefore, the practicability of the detection method is improved, which is beneficial to the promotion and application of the market.

Description

Capacitor fault detection method, device and wind turbine

technical field

Embodiments of the present invention relate to the technical field of power electronics, and in particular, to a method and device for detecting a capacitor fault, and a wind turbine.

Background technique

In generator sets, converters are often used to change the voltage, frequency, number of phases and other electrical quantities or characteristics in the generator set; in order to ensure the normal use of the converter, a filter for filtering is set in the generator set. Support capacitors; however, with the increase in the use time of the generator set, the support capacitors in the generator set may fail such as leakage, bulging, shrinkage or damage of the insulation. In severe cases, the failure of the support capacitors may lead to the failure of the IGBT circuit module. , The converter cabinet catches fire, which will bring great economic losses to users.

Therefore, in order to avoid the above situation, it is necessary to regularly detect the support capacitors in the generator set. In the prior art, the way to detect the support capacitors is usually to regularly arrange maintenance personnel to observe the use status of the support capacitors, which not only increases the Labor costs and labor costs, and due to the distribution of the support capacitors in the generator set, the inspectors cannot effectively observe each support capacitor, thereby reducing the accuracy and reliability of the inspection.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a capacitor fault detection method, device, and wind turbine, which can effectively overcome the problems in the prior art that increase labor costs and labor costs, and reduce detection accuracy and reliability.

An aspect of the embodiments of the present invention provides a method for detecting a capacitor fault, including:

Obtain the initial equivalent series resistance of the support capacitor in the generator set and the working equivalent series resistance of the support capacitor after a preset time period;

According to the initial equivalent series resistance and the working equivalent series resistance, it is determined whether the support capacitor fails.

The method for detecting a capacitor fault as described above, wherein determining whether the support capacitor fails according to the initial equivalent series resistance and the working equivalent series resistance, specifically includes:

If the working equivalent series resistance is greater than or equal to three times the initial equivalent series resistance, it is confirmed that the support capacitor fails; or,

If the working equivalent series resistance is less than three times the initial equivalent series resistance, it is confirmed that the support capacitor is in a normal working state.

The method for detecting a capacitor fault as described above, obtaining the working equivalent series resistance of the support capacitor after a preset period of time, specifically includes:

Acquiring rotational speed information of the generator in the generator set and ripple voltage information of the DC bus in the generator set;

The working equivalent series resistance is determined according to the rotational speed information and the ripple voltage information.

In the method for detecting a capacitor fault as described above, the determining of the working equivalent series resistance according to the rotational speed information and the ripple voltage information specifically includes:

acquiring the voltage average value information of the DC bus;

determining the ratio information σ of the voltage average information and the ripple voltage information according to the voltage average information and the ripple voltage information;

The ratio information σ, the rotational speed information n and the working equivalent series resistance R are fitted and calculated by the least square method, and the formula R=β ₀ +β ₁ n+β ₂ σ is obtained, wherein β ₀ , β ₁ and β ₂ are constants;

The working equivalent series resistance is determined according to the formula R=β ₀ +β ₁ n+β ₂ σ.

In the above-mentioned method for detecting a capacitor fault, the working equivalent series resistance is determined according to the formula R=β ₀ +β ₁ n+β ₂ σ, which specifically includes:

According to the R=β ₀ +β ₁ n+β ₂ σ, the formula Y=XB+U is obtained, where, U is a constant;

According to the formula β ₀ , β ₁ and β ₂ are obtained by calculation, and according to the β ₀ , β ₁ and β ₂ , the relationship between the working equivalent series resistance and the rotational speed information and the ratio information is determined as R=g( n,σ);

The working equivalent series resistance is determined according to the formula R=g(n,σ).

In the above-mentioned method for detecting a capacitor failure, after confirming that the support capacitor fails, the method further includes:

Send an alarm signal to a preset alarm device.

Another aspect of the embodiments of the present invention provides a device for detecting a capacitor fault, including:

an acquisition module, configured to acquire the initial equivalent series resistance of the support capacitor in the generator set and the working equivalent series resistance of the support capacitor after a preset time period;

A processing module, configured to judge whether the support capacitor fails according to the initial equivalent series resistance and the working equivalent series resistance.

The above-mentioned detection device for capacitor fault, and the processing module is specifically used for:

If the working equivalent series resistance is greater than or equal to three times the initial equivalent series resistance, it is confirmed that the support capacitor fails; or,

If the working equivalent series resistance is less than three times the initial equivalent series resistance, it is confirmed that the support capacitor is in a normal working state.

The above-mentioned detection device for capacitance faults, the acquisition module is specifically used for:

Acquiring rotational speed information of the generator in the generator set and ripple voltage information of the DC bus in the generator set;

The working equivalent series resistance is determined according to the rotational speed information and the ripple voltage information.

The above-mentioned detection device for capacitance faults, the acquisition module is also specifically used for:

acquiring the voltage average value information of the DC bus;

determining the ratio information σ of the voltage average information and the ripple voltage information according to the voltage average information and the ripple voltage information;

The ratio information σ, the rotational speed information n and the working equivalent series resistance R are fitted and calculated by the least square method, and the formula R=β ₀ +β ₁ n+β ₂ σ is obtained, wherein β ₀ , β ₁ and β ₂ are constants;

The working equivalent series resistance is determined according to the formula R=β ₀ +β ₁ n+β ₂ σ.

The above-mentioned detection device for capacitance faults, the acquisition module, is also used for:

After it is determined that the functional relationship between the working equivalent series resistance R, the rotational speed n of the generator, and the ratio information σ is R=β ₀ +β ₁ n+β ₂ σ, according to the R=β ₀ +β ₁ n+β ₂ σ, the formula Y=XB+U is obtained, where, U is a constant;

According to the formula β ₀ , β ₁ and β ₂ are obtained by calculation, and according to the β ₀ , β ₁ and β ₂ , the relationship between the working equivalent series resistance and the rotational speed information and the ratio information is determined as R=g( n,σ);

The working equivalent series resistance is determined according to the formula R=g(n,σ).

In the above-mentioned capacitor failure detection device, the processing module is further configured to send an alarm signal to a preset alarm device after confirming that the support capacitor fails.

Yet another aspect of the embodiments of the present invention provides a wind power generating set, including the above-mentioned device for detecting a capacitor fault.

The capacitor fault detection method, device and wind power generator set provided by the present invention obtain the initial equivalent series resistance and the working equivalent series resistance of the supporting capacitor in the generator set, and obtain the initial equivalent series resistance and the working equivalent series resistance according to the obtained initial equivalent series resistance and working equivalent series resistance. By connecting capacitors in series, it is possible to accurately and effectively determine whether the support capacitors are invalid, which effectively reduces labor costs and labor costs, and also improves the accuracy and reliability of the detection and judgment of support capacitors, ensuring the stable and reliable operation of the generator set. Therefore, the practicability of the detection method is improved, which is beneficial to the promotion and application of the market.

Description of drawings

1 is a schematic flowchart of a method for detecting a capacitor fault according to an embodiment of the present invention;

2 is a schematic flowchart of a method for detecting a capacitor fault according to another embodiment of the present invention;

3 is a schematic flowchart of a method for detecting a capacitor fault according to another embodiment of the present invention;

FIG. 4 is a schematic structural diagram of an apparatus for detecting a capacitor fault according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a support capacitor fault detection device according to an embodiment of the present invention.

Detailed ways

The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

FIG. 1 is a schematic flowchart of a method for detecting a capacitor fault according to an embodiment of the present invention; with reference to FIG. 1 , it can be seen that this embodiment provides a method for detecting a capacitor fault, and the detection method is used to detect the working state of the capacitor. To make an effective judgment, specifically, the detection method includes:

S11: Obtain the initial equivalent series resistance of the support capacitor in the generator set and the working equivalent series resistance of the support capacitor after a preset time period;

Under normal circumstances, the Boost booster circuit is used in the generator set, and the support capacitor is the filter capacitor of the Boost circuit. The support capacitor will degrade with the increase of use time. The most obvious degradation of the support capacitor is due to the loss of the capacitor electrolyte. At the same time, the existence of the equivalent series resistance will lead to the power loss of the support capacitor, which will increase the core temperature of the support capacitor and accelerate the degradation of the support capacitor; therefore, the equivalent The series resistance is an important parameter for judging the working state of the support capacitor.

In addition, the support capacitors in the generator set in this embodiment may include various types due to the structure of the generator set. For example, the support capacitors may include: the first support capacitor between the DC positive busbar and the O-row in the generator set, the power generation The second supporting capacitor between the DC negative busbar and the O row in the generator set, at this time, correspondingly, the initial equivalent series resistance includes: the first supporting capacitor between the DC positive busbar and the O row in the generator set The first initial equivalent resistance of the generator set, the second initial equivalent resistance of the second support capacitor between the rectifier negative busbar and the O row in the generator set; corresponding to the support capacitor, the working equivalent series resistance may include: power generation The first current equivalent resistance of the first supporting capacitor between the DC positive busbar and the O row in the generator set, the second current equivalent resistance of the second supporting capacitor between the rectified negative busbar and the O row in the generator set , it should be noted that no matter what type of support capacitor it is, the equivalent series resistance and the working equivalent series resistance can be obtained in the same way, and for the specific acquisition of the initial equivalent series resistance and the working equivalent series resistance The specific method is not limited, and those skilled in the art can directly detect and obtain the initial equivalent series resistance or working equivalent series resistance of the supporting capacitor through a detection device (such as an LCR tester, etc.); of course, those skilled in the art can also The initial equivalent series resistance and the working equivalent series resistance can be obtained in other ways.

In addition, it is worth noting that the initial equivalent series resistance mentioned in this embodiment is the initial equivalent series resistance when the generator set enters the normal working state after starting. At this time, in order to avoid the accuracy and reliability of the support capacitor detection, the equivalent series resistance after the generator set starts and enters a stable state is defined as the initial equivalent series resistance, which effectively ensures the detection of capacitor faults. accurate reliability.

S12: According to the initial equivalent series resistance and the working equivalent series resistance, determine whether the support capacitor fails.

It should be noted that when judging the working state of a single support capacitor, the initial equivalent series resistance and working equivalent series resistance are the initial equivalent series resistance and working equivalent series resistance corresponding to the above single support capacitor. Equivalent series resistance; in addition, this embodiment does not limit the specific analysis process for determining whether the support capacitor fails according to the initial equivalent series resistance and the working equivalent series capacitance, and those skilled in the art can set it according to specific design requirements, such as : The analysis and processing process is set to input the initial equivalent series resistance and the working equivalent series resistance into the corresponding comparison formula model, if a certain condition of the formula model is satisfied, then it can be judged whether the support capacitor fails; Technicians can also use other methods to determine the working state of the support capacitor through the initial equivalent series resistance and the working equivalent series resistance, as long as it can accurately and reliably determine whether the support capacitor fails, which will not be repeated here.

In the method for detecting a capacitor fault provided in this embodiment, the initial equivalent series resistance and the working equivalent series resistance of the supporting capacitor in the generator set are obtained, and according to the obtained initial equivalent series resistance and the working equivalent series capacitance, the Accurately and effectively judge whether the support capacitor fails, effectively reducing labor costs and labor costs, and also improving the accuracy and reliability of support capacitor detection and judgment, ensuring the stability and reliability of the generator set. The practicability of the detection method is beneficial to the promotion and application of the market.

FIG. 2 is a schematic flowchart of a method for detecting a capacitor fault according to another embodiment of the present invention; on the basis of the above-mentioned embodiment, it can be seen with continued reference to FIGS. 1-2 that in this embodiment, according to the initial equivalent series resistance and Working equivalent series resistance, the specific judgment strategy for judging whether the support capacitor fails is not limited, and those skilled in the art can set it according to specific design requirements. It increases with the use of time, and when the working equivalent series resistance increases to about three times the initial equivalent series resistance, the support capacitor is basically in a failed state at this time. Therefore, according to the initial equivalent series resistance and The working equivalent series resistance, to determine whether the support capacitor fails, is set to include:

S121: If the working equivalent series resistance is greater than or equal to three times the initial equivalent series resistance, confirm the failure of the support capacitor; or,

As the use time of the support capacitor increases, the working equivalent series resistance will continue to increase. When the working equivalent series resistance increases to greater than or equal to three times the initial equivalent series resistance, it can be confirmed that the support capacitor at this time fails; among them , the user can set the judgment time period according to specific design requirements. For example, the judgment time period can be set to 1h, 2h or 30min, etc. Then, according to the preset judgment time period, the collected work will be equivalently connected in series The resistance is compared with the initial equivalent series resistance, which effectively realizes the effective automatic monitoring of the working state of the support capacitor, and improves the practicability of the detection method.

S122: If the working equivalent series resistance is less than three times the initial equivalent series resistance, confirm that the support capacitor is in a normal working state.

As the service time of the support capacitor increases, the working equivalent series resistance will continue to increase. When the working equivalent series resistance is less than three times the initial equivalent series resistance, it can be confirmed that the support capacitor at this time is in a normal working state.

By comparing the working equivalent series resistance with three times the initial equivalent series resistance, the working state of the support capacitor can be effectively judged according to the comparison result, which improves the accuracy and reliability of judging the working state of the support capacitor, and further improves the detection The precision used by the method.

3 is a schematic flowchart of a method for detecting a capacitor fault provided by another embodiment of the present invention; on the basis of the above-mentioned embodiment, it can be seen that with reference to FIGS. The specific method of the initial equivalent series resistance and the initial equivalent series resistance is not limited, wherein, those skilled in the art can use the same acquisition method to obtain the working equivalent series resistance and the initial equivalent series resistance according to specific design requirements. The accuracy of the series resistance and the initial equivalent series resistance can be set to specifically include:

S111: Obtain the rotational speed information of the generator in the generator set and the ripple voltage information of the DC bus in the generator set;

For the speed information of the generator, a speed sensor can be set on the generator, and the speed information can be obtained through the speed sensor. For the ripple voltage information, the ripple voltage is the AC component of the DC voltage, and the peak-to-peak value is used to represent the ripple. The magnitude of the wave voltage, for example: based on the 7s data of the generator set, the ripple voltage of the DC voltage when the generator set speed is n is calculated as: U=U _max -U _min , where U _max is the obtained waveform data. The maximum value, U _min is the minimum value of the obtained waveform data, that is, the ripple voltage information can be obtained by obtaining the maximum value and the minimum value of the waveform data;

In addition, the ripple voltage information may include multiple types according to the architecture of the generator set. For example, the ripple voltage information may include: positive ripple voltage information of the positive DC bus voltage and negative ripple voltage information of the negative DC bus voltage; of course , whether it is positive ripple voltage information or negative ripple voltage information, can be obtained and calculated in the same way.

S112: Determine the working equivalent series resistance according to the rotational speed information and the ripple voltage information.

Wherein, in this embodiment, the specific determination method for determining the working equivalent series resistance according to the rotational speed information and the ripple voltage information is not limited, and those skilled in the art can set it according to the specific design requirements. Determine the working equivalent series resistance according to the speed information and the ripple voltage information, and the settings include:

S1121: Obtain the average voltage information of the DC bus;

Among them, for the generator set, the speed of the generator in the generator set is different, and the operating power of the generator set is different. Under different power, the average value and ripple voltage of the DC bus voltage are different. Therefore, the voltage can be obtained according to the mean value theorem. Average value information, for example: also based on the 7s data of the generator set, the average voltage information when the generator speed is n is calculated as: Among them, N is the number of sampling points, and u(i) is the ith sampling point of the DC bus voltage; wherein, the average voltage information of the DC bus can include various types according to the structure of the DC bus: for example, including the average of the positive voltage of the DC bus The value information and the average value information of the negative voltage of the DC bus, etc., and regardless of the type of voltage average information, the above method can be used to obtain.

S1122: Determine the ratio information σ of the voltage average information and the ripple voltage information according to the voltage average information and the ripple voltage information;

When the voltage average value information may include positive voltage average value information and negative voltage average value information, the ratio information may include the ratio information of the DC bus positive voltage average value to the ripple voltage information and the difference between the DC bus negative voltage average value and the ripple voltage. ratio information.

S1123: Use the least squares method to compare the value information σ, the rotational speed information n and the working equivalent series resistance R to perform fitting calculation, and obtain the formula R=β ₀ +β ₁ n+β ₂ σ, where β ₀ , β ₁ and β ₂ is a constant;

Among them, the least squares method is to find the best function that matches the data by minimizing the average sum of the errors. The least squares method can simply obtain the data of the position, and make the difference between the obtained data and the actual data. The sum of squares is the smallest. Therefore, by fitting and calculating the extracted characteristic parameters by the least squares method, the relationship between the working equivalent series resistance and the speed information and ratio information can be obtained, and the parameter value at a certain time in the future can be effectively predicted.

S1124: Determine the working equivalent series resistance according to the formula R=β ₀ +β ₁ n+β ₂ σ.

Among them, for the generator set, it can include multiple equivalent series resistance information, for example, it can include the working equivalent series resistance between the DC positive busbar and the O row, and the working equivalent between the DC negative busbar and the O row. The series capacitance and the working equivalent series resistance between the DC positive busbar and the DC negative busbar, wherein, the above three types of working equivalent series resistance information can be calculated and obtained by the above method; _{β 0} , β ₁ and _{β 2} are constants _of include:

S11241: According to R=β ₀ +β ₁ n+β ₂ σ, the formula Y=XB+U is obtained, wherein, U is a constant;

S11242: According to formula β ₀ , β ₁ and β ₂ are obtained by calculation, and according to β ₀ , β ₁ and β ₂ , the relationship between the working equivalent series resistance and the speed information and ratio information is determined as R=g(n,σ);

S11243: Determine the working equivalent series resistance according to the formula R=g(n,σ).

Through the above matrix deduction process, the functional relationship between the working equivalent series resistance and the speed information and ratio information can be effectively obtained. Through the above functional relationship, the working equivalent series resistance can be obtained accurately and effectively, and the working equivalent series resistance can be effectively improved. The accuracy and reliability of the series resistance acquisition ensures the accuracy and reliability of the judgment of the detection method.

On the basis of the above-mentioned embodiment, and referring to the accompanying drawings 1-3, it can be seen that after judging that the capacitor is faulty, in order to avoid accidents such as fire in the generator set, after confirming the failure of the supporting capacitor, the method is set to further include:

S123: Send an alarm signal to a preset alarm device.

Wherein, the alarm device includes: LED lights and/or a buzzer, and there may be multiple LED lights, and the alarm device may include LED lights alone, that is, after it is determined that the support capacitor fails, the LED lights flash to remind the user of the support capacitor In the state of failure, in addition, when it is necessary to perform fault detection on multiple support capacitors in the generator set, in order to remind the user of the location of the specific fault support capacitors, each support capacitor can be pre-connected with the LED lights of different colors in the alarm device. After connecting, the user can judge the specific faulty support capacitor through the flashing color of the LED light; the alarm device can include a buzzer alone, that is, after confirming the failure of the support capacitor, the buzzer sounds to remind the user that the capacitor is in a failed state; Alternatively, the alarm device may also include an LED light and a buzzer, that is, after it is determined that the support capacitor fails, the buzzer sounds and the LED light flashes to remind the user that the capacitor is in a failed state. The specific structure of the alarm device can be based on user needs. Make settings, as long as it can play the role of alarm and prompt.

Through the set alarm device, after the failure of the support capacitor is found, the user will be given an alarm reminder, so that the user can replace the support capacitor in time and repair the support capacitor, which can effectively avoid the occurrence of accidents such as failure of the IGBT circuit module and fire of the converter cabinet, and then The waste and loss of manpower, material resources and financial resources are reduced, the practicability of the capacitor fault detection method is effectively improved, and the market promotion and application are facilitated.

In the specific application, it is assumed that the time period for judging the fault of the support capacitor is 30 minutes, and, for the generator set, the generator set includes the first initial stage of the first support capacitor between the DC positive busbar and the O row in the generator set, etc. The effective resistance R ₁ , and the second initial equivalent resistance R ₂ of the second support capacitor between the rectifier negative busbar and the O row in the generator set, then, every 30min, R ₁ and R ₂ will be The initial equivalent series resistance R ₁ (0) is compared with the second initial equivalent series resistance R ₂ (0); when R ₁ ≥ 3R ₁ (0), it represents the first There is a failure of the support capacitor; when R ₂ ≥ 3R ₂ (0), it means that the first support capacitor between the DC negative busbar and the O row has a failure.

Figure 5 provides a schematic structural diagram of a support capacitor fault detection device. Referring to Figure 5, it can be seen that the support capacitor fault detection device mainly includes a sampling circuit, an auxiliary power supply circuit, a processor and a communication interface, wherein the processor is TMS320F2812, The SCI interface of the processor TMS320F2812 is converted through the MAX232 chip to realize asynchronous serial communication; the power supply voltage of the processor TMS320F2812 is 3.3V, and the power supply voltage of the operational amplifier is ±15V; the switching voltage regulator LM3596 is used to convert 24V to 3.3V For processor use, DC/DC power module MDA5-24D15 is used to convert 24V to ±15V for Hall voltage sensor and operational amplifier.

As for the connection mode of the generator set, the connection mode between port J1 and the generator set can be set as: port J1-1 is connected with the generator set X24V1.5; port J1-2 is connected with the generator set X0V1.5; port J1-3 is connected with Pin 1 of the high-voltage IO board of the unit is connected; ports J1-4 are connected to the pin 2 of the high-voltage IO board of the unit; ports J1-5 are connected to the pin 3 of the high-voltage IO board of the unit; 7 is connected to pin 4 of the Overspeed module of the unit sensor, thereby completing the hardware architecture of the detection device.

For the above detection device, the detection device includes a collection circuit for collecting data. Specifically, the sampling circuit includes a positive voltage sampling circuit for collecting the positive voltage of the DC bus (including: resistor R ₁ , voltage sensor, operational amplifier, Resistor _R3 and resistor _C1 , etc.), a negative voltage sampling circuit for collecting the negative voltage of the DC bus ₍ including: resistor R4, voltage sensor, operational amplifier, resistor _R6 and resistor _C2 , etc.) and for collecting generators A rotational speed sampling circuit for rotational speed information (including: resistor R ₈ , resistor R ₁₀ , operational amplifier, resistor R ₉ , etc.).

Specifically, when collecting data information, when the unit is running, the real-time values of each state quantity are collected and stored; it includes generator speed, DC bus positive voltage and DC bus negative voltage; the generator speed can be collected by the sensor Overspeed module. After that, it is sent to the processor through the differential proportional operation circuit. The positive voltage of the DC bus and the negative voltage of the DC bus are collected by the Hall voltage sensor, and then sent to the processor through the voltage follower. Specifically, the positive voltage of the DC bus can be collected every 10s. The negative voltage of the DC bus and the speed of the generator are extracted every 30mins, and the first initial equivalent resistance R ₁ and the second initial equivalent resistance R ₂ of the current unit are calculated by the established formula, which is the same as the first initial equivalent resistance R 2 . The equivalent series resistance R ₁ (0) is compared with the second initial equivalent series resistance R ₂ (0). If R ₁ ≥ 3R ₁ (0), it means that the first When the support capacitor is in failure, the red alarm light is on (that is, L ₁ is flashing); when R ₂ ≥ 3R ₂ (0), it means that the first support capacitor between the DC negative busbar and the O-bar is in failure, and the alarm is given. The yellow light is on (that is, L ₂ is flashing), and the generated list of collected data and analysis results 30 mins before the moment can also be uploaded. For the specific format, please refer to Table 1 and Table 2:

Time(s) U_dc+ U_dc- n -1800 -1790 -1780 … 0

Table 1: Data Collection Form

Result U_ave+ U_ave- U_pp+ U_pp- δ₁ δ₂ R₁ R₂ R₁(0) R₂(0) Value

Table 2: Results comparison analysis table

Through the above data collection table and result comparison analysis table, the data information collected by this detection method can be clearly and intuitively understood, which is convenient for users to check the working status of each component in the generator set, and can quickly and accurately judge the supporting capacitance Whether there is a fault or not, the accuracy and reliability of the detection method of the capacitor fault detection method is effectively improved, which is beneficial to the promotion and application of the market.

FIG. 4 is a schematic structural diagram of a capacitor fault detection device provided by an embodiment of the present invention; with reference to FIG. 4 , it can be seen that the present embodiment provides a capacitor fault detection device, and the detection device is used to determine whether the capacitor is faulty , specifically, including:

The acquisition module 1 is used to acquire the initial equivalent series resistance of the support capacitor in the generator set and the working equivalent series resistance of the support capacitor after a preset time period;

This embodiment does not limit the specific shape and structure of the acquisition module 1, and those skilled in the art can arbitrarily set it according to the functions it realizes. For example, the acquisition module 1 can be set as a sensor or an LCR tester, etc. It is enough to realize the above functions and effects, which will not be repeated here; in addition, the realization process and realization effect of the operation steps realized by the acquisition module 1 are the same as the realization process and realization effect in step S11 in the above-mentioned embodiment. For details, please refer to the above-mentioned The content of the statement will not be repeated here.

The processing module 2 is used for judging whether the support capacitor fails according to the initial equivalent series resistance and the working equivalent series resistance.

The specific shape and structure of the processing module 2 is not limited in this embodiment, and those skilled in the art can arbitrarily set it according to the functions it realizes. For example, the processing module 2 can be set as a central processing unit CPU, etc. The functional effect is sufficient, and will not be repeated here; in addition, the implementation process and implementation effect of the operation steps implemented by the processing module 2 are the same as the implementation process and implementation effect in step S12 in the above-mentioned embodiment, and the specific content can be referred to the above statement. , and will not be repeated here.

In the capacitor fault detection device provided in this embodiment, the initial equivalent series resistance and the working equivalent series resistance of the supporting capacitor in the generator set are acquired through the acquisition module 1, and the processing module 2 is used to obtain the initial equivalent series resistance and the working equivalent series resistance according to the obtained initial equivalent series resistance and the working equivalent series resistance. Equivalent series capacitor can accurately and effectively judge whether the support capacitor fails, effectively reducing labor costs and labor costs, and also improving the accuracy and reliability of the detection and judgment of the support capacitor, ensuring the working efficiency of the generator set. It is stable and reliable, thereby improving the practicability of the detection device, which is beneficial to the promotion and application of the market.

On the basis of the above-mentioned embodiment, referring to FIG. 4, it can be seen that in this embodiment, the specific judging strategy for judging whether the support capacitor is invalid according to the initial equivalent series resistance and the working equivalent series resistance of the processing module 2 is not limited. Those skilled in the art can set it according to specific design requirements. After long-term exploration and research by the inventor, it is found that the working equivalent series resistance will continue to increase with the increase of use time, and when the working equivalent series resistance increases to the initial value When the equivalent series resistance is about three times, the support capacitor is basically in a failed state at this time. Therefore, the processing module 2 is set to be specifically used for:

If the working equivalent series resistance is greater than or equal to three times the initial equivalent series resistance, confirm the failure of the support capacitor; or,

If the working equivalent series resistance is less than three times the initial equivalent series resistance, confirm that the support capacitor is in normal working condition.

The implementation process and implementation effect of the operation steps implemented by the processing module 2 in this embodiment are the same as the implementation process and implementation effect in steps S121 and S122 in the above-mentioned embodiment.

By comparing the working equivalent series resistance with three times the initial equivalent series resistance, the working state of the support capacitor can be effectively judged according to the comparison result, which improves the accuracy and reliability of judging the working state of the support capacitor, and further improves the detection The precision with which the device is used.

On the basis of the above-mentioned embodiment, referring to FIG. 4, it can be seen that this embodiment does not limit the specific manner in which the acquisition module 1 obtains the working equivalent series resistance and the initial equivalent series resistance. For specific design requirements, the same acquisition method is used to obtain the working equivalent series resistance and the initial equivalent series resistance. In order to improve the accuracy of obtaining the working equivalent series resistance and the initial equivalent series resistance, the acquisition module 1 can be set to the specific Used for:

Obtain the speed information of the generator in the generator set and the ripple voltage information of the DC bus in the generator set;

The implementation process and implementation effect of the operation steps implemented by the acquisition module 1 in this embodiment are the same as the implementation process and implementation effect in step S111 in the above-mentioned embodiment.

The working equivalent series resistance is determined according to the speed information and the ripple voltage information.

Wherein, in this embodiment, the specific determination method for determining the working equivalent series resistance according to the rotational speed information and the ripple voltage information is not limited, and those skilled in the art can set it according to the specific design requirements. Acquisition module 1, set to be specifically also used for:

Obtain the voltage average information of the DC bus;

According to the voltage average information and the ripple voltage information, determine the ratio information σ of the voltage average information and the ripple voltage information;

The least square method is used to compare the value information σ, the rotational speed information n and the working equivalent series resistance R for fitting calculation, and the formula R=β ₀ +β ₁ n+β ₂ σ is obtained, where β ₀ , β ₁ and β ₂ are constant;

The implementation process and implementation effect of the operation steps implemented by the acquisition module 1 in this embodiment are the same as the implementation process and implementation effect in steps S1121-S1123 in the above-mentioned embodiment.

The working equivalent series resistance is determined according to the formula R=β ₀ +β ₁ n+β ₂ σ.

Among them, for the generator set, it can include multiple equivalent series resistance information, for example, it can include the working equivalent series resistance between the DC positive busbar and the O row, and the working equivalent between the DC negative busbar and the O row. The series capacitance and the working equivalent series resistance between the DC positive busbar and the DC negative busbar, wherein, the above three types of working equivalent series resistance information can be calculated and obtained by the above method; β ₀ , β ₁ and β ₂ are constants, therefore, in order to obtain the working equivalent series resistance more accurately, the acquisition module is set to also be used for:

After determining the functional relationship between the working equivalent series resistance R, the generator speed n, and the ratio information σ as R=β ₀ +β ₁ n+β ₂ σ, according to R=β ₀ +β ₁ n+β ₂ σ , the formula Y=XB+U is obtained, where, U is a constant;

According to the formula β ₀ , β ₁ and β ₂ are obtained by calculation, and according to β ₀ , β ₁ and β ₂ , the relationship between the working equivalent series resistance and the speed information and ratio information is determined as R=g(n,σ);

Determine the working equivalent series resistance according to the formula R=g(n,σ).

The implementation process and implementation effect of the operation steps implemented by the acquisition module 1 in this embodiment are the same as the implementation process and implementation effect in steps S11241-S11243 in the above-mentioned embodiment.

Through the above matrix deduction process, the functional relationship between the working equivalent series resistance and the speed information and ratio information can be effectively obtained. Through the above functional relationship, the working equivalent series resistance can be obtained accurately and effectively, and the working equivalent series resistance can be effectively improved. The accurate and reliable acquisition of the series resistance ensures the accurate and reliable judgment of the detection device.

On the basis of the above-mentioned embodiment, continue to refer to accompanying drawing 4, after judging that the capacitor is faulty, in order to avoid accidents such as fire in the generator set, the processing module 2 is set to also be used for:

After confirming that the support capacitor fails, an alarm signal is sent to a preset alarm device.

The implementation process and implementation effect of the operation steps implemented by the processing module 2 in this embodiment are the same as the implementation process and implementation effect in step S123 in the above-mentioned embodiment.

Through the set alarm device, after the failure of the support capacitor is found, the user will be given an alarm reminder, so that the user can replace the support capacitor in time and repair the support capacitor, which can effectively avoid the occurrence of accidents such as failure of the IGBT circuit module and fire of the converter cabinet, and then The waste and loss of manpower, material resources and financial resources are reduced, the practicability of the capacitor fault detection device is effectively improved, and the market promotion and application are facilitated.

Another aspect of this embodiment provides a wind power generator set, which includes the above-mentioned capacitor fault detection device.

By setting the detection device for capacitor failure in the wind turbine, the working state of the support capacitor in the wind turbine can be obtained in a timely and effective manner, and when the support capacitor fails, an alarm prompt can be issued in time to avoid fire and other accidents. The occurrence of wind turbines ensures the safety and reliability of the use of wind turbines, and is beneficial to the promotion and application of the market.

In the several embodiments provided by the present invention, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware, or may be implemented in the form of hardware plus software functional units.

The above-mentioned integrated units implemented in the form of software functional units can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor (processor) to execute the methods described in the various embodiments of the present invention. some steps. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program codes .

Those skilled in the art can clearly understand that, for the convenience and brevity of the description, only the division of the above functional modules is used for illustration. The internal structure is divided into different functional modules to complete all or part of the functions described above. For the specific working process of the apparatus described above, reference may be made to the corresponding process in the foregoing method embodiments, and details are not described herein again.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. scope.

Claims (9)

1. A method of detecting a capacitive fault, comprising:

acquiring an initial equivalent series resistance of a support capacitor in a generator set and a working equivalent series resistance of the support capacitor after a preset time period;

judging whether the supporting capacitor fails or not according to the initial equivalent series resistance and the working equivalent series resistance;

the method includes the steps of obtaining a working equivalent series resistance of the support capacitor after a preset time period, and specifically includes:

acquiring rotating speed information of a generator in the generator set and ripple voltage information of a direct current bus in the generator set;

and determining the working equivalent series resistance according to the rotating speed information and the ripple voltage information.

2. The method according to claim 1, wherein the determining whether the support capacitor fails according to the initial equivalent series resistance and the working equivalent series resistance specifically includes:

if the working equivalent series resistance is greater than or equal to three times of the initial equivalent series resistance, confirming that the support capacitor fails; or,

and if the working equivalent series resistance is less than three times of the initial equivalent series resistance, confirming that the support capacitor is in a normal working state.

3. The method according to claim 1, wherein the determining the working equivalent series resistance according to the rotation speed information and the ripple voltage information specifically comprises:

acquiring voltage average value information of the direct current bus;

determining ratio information sigma of the voltage average value information and the ripple voltage information according to the voltage average value information and the ripple voltage information;

fitting and calculating the ratio information sigma, the rotating speed information n and the working equivalent series resistance R by adopting a least square method to obtain a formula R- β₀+β₁n+β₂σ, wherein, β₀、β₁And β₂Is a constant;

according to the formula R- β₀+β₁n+β₂σ determines the working equivalent series resistance.

4. The method of claim 2, wherein after confirming the support capacitance is failed, the method further comprises:

and sending an alarm signal to a preset alarm device.

5. A capacitive fault detection device, comprising:

the acquisition module is used for acquiring the initial equivalent series resistance of a support capacitor in the generator set and the working equivalent series resistance of the support capacitor after a preset time period;

the processing module is used for judging whether the supporting capacitor fails or not according to the initial equivalent series resistance and the working equivalent series resistance;

wherein, the collection module is specifically configured to:

acquiring rotating speed information of a generator in the generator set and ripple voltage information of a direct current bus in the generator set;

and determining the working equivalent series resistance according to the rotating speed information and the ripple voltage information.

6. The apparatus according to claim 5, wherein the processing module is specifically configured to:

if the working equivalent series resistance is greater than or equal to three times of the initial equivalent series resistance, confirming that the support capacitor fails; or,

and if the working equivalent series resistance is less than three times of the initial equivalent series resistance, confirming that the support capacitor is in a normal working state.

7. The capacitive fault detection device of claim 5, wherein the acquisition module is further configured to:

acquiring voltage average value information of the direct current bus;

determining ratio information sigma of the voltage average value information and the ripple voltage information according to the voltage average value information and the ripple voltage information;

fitting and calculating the ratio information sigma, the rotating speed information n and the working equivalent series resistance R by adopting a least square method to obtain a formula R- β₀+β₁n+β₂σ, wherein, β₀、β₁And β₂Is a constant;

according to the formula R- β₀+β₁n+β₂σ determines the working equivalent series resistance.

8. The apparatus according to claim 6, wherein the processing module is further configured to send an alarm signal to a preset alarm device after confirming the failure of the supporting capacitor.

9. Wind park comprising a capacitive fault detection device according to any of claims 5 to 8.