CN111856168B - Transformer fault detection method and box-type transformer - Google Patents
Transformer fault detection method and box-type transformer Download PDFInfo
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- CN111856168B CN111856168B CN201910322700.5A CN201910322700A CN111856168B CN 111856168 B CN111856168 B CN 111856168B CN 201910322700 A CN201910322700 A CN 201910322700A CN 111856168 B CN111856168 B CN 111856168B
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Abstract
The invention provides a transformer fault detection method and a box-type transformer, which comprises the following processes: judging whether the running state of the transformer is abnormal or not according to the first running parameter of the transformer, and controlling and adjusting the running state; judging whether the transformer fault is in the winding or not according to the second operation parameter of the transformer; a winding fault verification program for verifying whether a fault has actually occurred in the winding; detecting the type of winding fault; and through analysis of the internal temperature, the oil temperature and the oil pressure of the transformer and vibration signals, when the type of the winding fault is judged to be the iron core fault through the transformer vibration information, the iron core fault type is detected. The transformer fault detection method provided by the embodiment can accurately detect whether the transformer runs abnormally or fails, and can also judge the fault type and the specific position of the fault of the transformer, and particularly for a box-type transformer with a large size, maintenance personnel can conveniently and pertinently repair and replace the transformer.
Description
Technical Field
The invention relates to the field of transformers, in particular to a transformer fault detection method and a box-type transformer.
Background
The transformer is used as a component of power transmission and distribution of a power system, and the safety and the stability of the transformer have important significance for the development of national economy. Today, the breakdown of the power system caused by transformer accidents is more frequent, which is not only unfavorable for the rapid development of economy, but also seriously affects the normal life of residents. According to statistics, the number of accidents of 110kV and above power transformers in China is 284 from 1995 to 1999, the total accident capacity is 21360MVA, and the failures of the transformers mainly comprise iron core failures and winding failures if the number of accidents is divided according to the positions of the failures of the transformers. The failure of the iron core is mostly caused by the vibration of the transformer body, and the main causes of the vibration of the transformer body are the vibration of the transformer body and the vibration of the cooling device. After the transformer is electrified and operated, current flows in the winding, and an electromagnetic field is generated in the iron core and the winding; the iron core silicon steel sheet material is magnetostriction under the action of a magnetic field, namely the size of atoms is slightly deformed, so that the iron core vibrates, and the fundamental frequency of the iron core vibration frequency is 100Hz. The probability that a transformer winding fault occurs among the fault types of all transformers is highest. And the fault possibility of transformer winding faults is many, and the faults include winding short circuit, winding deformation, insulation aging faults and the like.
At present, a method for detecting a transformer fault in an electric power system is single, particularly for a box-type transformer with a large size, the type and the specific position of the fault cannot be specifically judged, and the severity of the fault cannot be effectively judged, so that field personnel can know the internal deformation condition of the transformer, the negative influence is generated, and the development of the next detection work is not facilitated.
Disclosure of Invention
In view of the above, the present invention is directed to a box type transformer for detecting transformer faults, so as to solve the above problems.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a transformer fault detection method is used for judging whether a tested transformer has a fault or not based on a preset fault numerical value range and a normal numerical value range, and comprises the following steps:
step S1: judging whether the running state of the transformer is abnormal or not according to the first running parameter of the transformer, and controlling and adjusting the running state;
step S2: judging whether the transformer fault is in the winding or not according to the second operation parameter of the transformer;
and step S3: a winding fault verification program for verifying whether a fault has actually occurred in the winding;
and step S4: detecting the type of winding fault; judging the type of winding fault through the analysis of the internal temperature, oil temperature and oil pressure and vibration signals of the transformer
Step S5: and when the transformer vibration information is judged to be the iron core fault, detecting the type of the iron core fault.
Further, the first operation parameter comprises internal temperature of the transformer, output current and/or output voltage, and the second operation parameter comprises internal temperature of the transformer, and vibration signal information of the transformer.
Furthermore, the temperature inside the transformer is detected through a temperature measurement sensing system, and the temperature measurement sensing system comprises a temperature processing module arranged on the outer wall of the transformer body and an infrared temperature measurement sensor extending into the transformer body.
Further, the step S1 includes:
step S11: starting the transformer to start running;
step S12: after the running time of the transformer reaches a first preset time, the detection device starts to detect the internal temperature T of the transformer;
step S13: judging whether the internal temperature T of the transformer detected by the temperature measurement sensing system is within a first preset temperature range delta T1 or not, and if so, continuing normal operation of the transformer; if the judgment result is no, executing the step S14;
step S14: executing a fault early warning detection program, warning workers to closely monitor the running condition of the transformer and detecting the output voltage of the transformer;
step S15: judging whether the output voltage is in a voltage range preset by the transformer, and executing an S2 fault judgment program when the judgment result is yes; if the judgment result is no, the fact that the temperature inside the transformer exceeds the first preset temperature range is caused by overload of the transformer is indicated, and at this time, step S15 is executed to control the load reduction operation of the transformer.
Step S16: regulating the transformer to reduce its capacity and current limit I max . I.e. to limit the operation of the transformer not to exceed the current limit I max 。
Further, the step S2 includes:
step S21: detecting the internal temperature T of the transformer again;
step S22: judging whether the internal temperature T of the transformer is within a second preset temperature range delta T 2 If yes, indicating that the interior of the transformer is moderately overheated, and executing step S23; if the judgment result is no, executing the step S14;
step S23: sampling vibration information of the transformer according to set sampling frequency and sampling time, intercepting a vibration signal of the transformer in a whole period, performing wavelet denoising on the intercepted vibration signal, performing Fourier spectrum analysis, and simultaneously solving component amplitudes of the vibration signal at 50Hz, 150Hz, 100Hz and 200 Hz. Continuously detecting the oil temperature and the oil pressure of the transformer and sending detected signals to a control device;
step S24: judging whether the amplitude of the frequency spectrum component of 100Hz is larger than a first preset threshold value phi or not 1 If the fault is the winding fault, the fault of the transformer is judged to be possible to be the winding fault, a winding fault verification program S3 needs to be further executed, if the fault is not judged to be possible, the fault is the fault of other parts except the winding, such as the fault of the iron core, a step S5 needs to be executed, and whether the fault is the fault of the iron core is further detected.
Further, the step S3 includes:
step S31: acquiring leakage reactance parameters after the short circuit of the transformer;
step S32: judging whether the obtained leakage reactance parameter value after the short circuit of the transformer is in a fault value range or not, if so, judging the fault of the transformer winding, executing the step S4, and judging the fault type of the specific transformer winding; if not, the transformer fault is a fault of other parts except the iron core and the winding, and a shutdown inspection alarm prompt is given, so that shutdown inspection is required.
Further, the step S3 includes:
step S41: acquiring the oil temperature and oil pressure change curve of the transformer, judging whether the oil temperature or the oil pressure change curve of the transformer is in a continuously rising state, if so, judging that the transformer fault is a winding insulation aging fault, and giving an insulation aging alarm prompt. If not, it is determined that the transformer winding fault is not caused by insulation aging, and further determination is required, and step S42 is performed.
Step S42: the transformer internal temperature T is detected again.
Step S43: judging whether the internal temperature is in a third preset temperature range delta T 3 If yes, indicating that the interior of the transformer is severely overheated, and executing step S44; if the judgment result is no, the transformer fault is the fault of other parts except the iron core and the winding, and the machine needs to be stopped for inspection.
Step S44: and detecting the vibration information of the transformer, and calculating the sum of the amplitudes of the frequency spectrum components of 100Hz and 200 Hz.
Step S45: judging whether the ratio of the sum of the amplitudes of the spectral components at 50Hz and 150Hz to the sum of the amplitudes of the spectral components at 100Hz and 200Hz is larger than a second preset threshold phi 2 If the fault is the winding deformation fault, the transformer fault is judged to be the fault of other parts except the iron core and the winding, and the machine needs to be stopped for inspection.
Further, the step S5 of detecting the type of the core fault includes:
s51: and measuring the insulation resistance between the iron core frames.
S52: and judging whether the iron core frames are short-circuited, if so, judging that the iron core is short-circuited, otherwise, executing S53, and further detecting the type of the iron core fault.
Further, the insulation resistance between the iron core frames is measured by a resistance measuring device, and the resistance measuring device is a multimeter or a megohmmeter.
S53: and detecting the vibration information of the transformer, and calculating the sum of the amplitudes of the frequency spectrum components of 50Hz and 150 Hz.
S54: judging whether the sum of the amplitudes of the frequency spectrum components of 50Hz and 150Hz is greater than a third preset threshold phi or not 3 If so, judging that the iron core fault is a loosening fault, otherwise, indicating that the transformer fault is a fault of other parts except the iron core and the winding and needing to be stopped for inspection.
Compared with the prior art, the transformer fault detection method has the following advantages:
the transformer fault detection method provided by the embodiment can not only accurately detect whether the transformer runs abnormally or fails, but also prompt maintenance personnel to adjust the load of the transformer in time, so that the transformer is prevented from being burnt down due to long-time overload. Meanwhile, the fault type and the specific position of the fault of the transformer can be judged, particularly for a box-type transformer with a large size, whether the short-circuit fault of the iron core occurs or not can be accurately detected, maintenance personnel can conveniently and pertinently maintain and replace the transformer, the workload of the maintenance personnel is reduced, and the power operation, maintenance and management efficiency is improved.
The invention also provides a box-type transformer, and the transformer fault detection method is used, the box-type transformer comprises a box body, a transformer body and a detection system, the transformer body comprises a transformer winding, a transformer iron core and a cooling device, cooling oil is stored in the cooling device, the detection system comprises a control device, an analysis module, a timer and a detection device, the timer is used for timing and analyzing the running time of the transformer, the detection device feeds detected data parameters back to the analysis module, the analysis module is used for analyzing and calculating the detected data and then conveying the data to the control device, and the control device is used for controlling the alarm device to give corresponding alarm prompts.
Furthermore, the detection device comprises a temperature measurement sensing system, a vibration information detection device and a leakage reactance parameter measurement system, the temperature measurement sensing system comprises a temperature processing module installed on the outer wall of the transformer body and an infrared temperature measurement sensor extending into the transformer body, the vibration information detection device is a vibration sensor, the vibration sensor is arranged right above the middle position between the high-voltage winding and the low-voltage winding in the transformer, and the leakage reactance parameter measurement system comprises simulation software and a simulation transformer.
Compared with the prior art, the transformer fault detection system and the transformer fault detection method have the same advantages, and are not described again.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a flowchart of a method for detecting a fault of a box-type transformer according to an embodiment of the present invention;
fig. 2 is a partial flowchart of a fault detection method for a box-type transformer according to a second embodiment of the present invention;
fig. 3 is a flowchart of a winding fault verification procedure in the fault detection method of the box-type transformer according to the second embodiment of the present invention;
fig. 4 is a flowchart of a core fault type detection procedure in the fault detection method of the box-type transformer according to the second embodiment of the present invention.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The descriptions of "first", "second", etc. mentioned in the embodiments of the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit ly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
Example 1
As shown in fig. 1, a transformer fault detection method provided in an embodiment of the present invention is a flowchart, where the transformer fault detection method in this embodiment judges whether a tested transformer has a fault based on a predetermined fault value range and a normal value range, and specifically includes the following steps:
step S1: and judging whether the running state of the transformer is abnormal or not through the first running parameter of the transformer, and controlling and adjusting the running state.
Wherein the first operating parameter comprises a transformer internal temperature, an output current and/or an output voltage.
Firstly, each operation parameter of the transformer starts to be detected after the transformer operates for a period of time, and due to the limitation of the internal structure of the transformer, heat can be generated inside the transformer after the transformer starts to operate, so that the temperature is increased, but when the transformer operates normally and the state is stable, the temperature can be maintained within a normal range. Therefore, when the temperature inside the transformer is detected to be beyond the normal range, the transformer is indicated to be possible to have a fault or run in an overload mode.
Specifically, the internal temperature of the transformer is detected through a temperature measurement sensing system, and the temperature measurement sensing system comprises a temperature processing module arranged on the outer wall of the transformer body and an infrared temperature measurement sensor extending into the transformer body. For the traditional contact type temperature measuring sensor, because when the transformer operates abnormally, the winding and the iron core of the transformer are easy to generate sudden serious overheating, the damage to the sensor arranged inside the transformer is large, but if the temperature sensor is far away from the iron core and the winding, the temperature inside the transformer is easy to be detected inaccurately, and the temperature inside the transformer cannot be reflected effectively in time. In this embodiment, the infrared ray emitted by the temperature probe of the infrared temperature sensor continuously scans and measures the temperature of the transformer winding and the transformer core in the transformer body in a non-contact manner, and simultaneously transmits the detected temperature signal to the temperature processing module, the temperature processing module processes and calculates the temperature signal transmitted by the infrared temperature sensor and transmits the result to the control device, and the control device judges whether the operation state of the transformer is normal or not according to the temperature value. If the temperature inside the transformer is detected to be abnormal, the operation is abnormal, and further detection and judgment are required to be executed. In this embodiment, the temperature sensor is set as an infrared temperature sensor, so that non-contact detection with the iron core and the winding inside the transformer is realized, and the service life of the sensor is prolonged.
The method comprises the steps of judging whether the temperature abnormality in the transformer is caused by transformer faults or overload by detecting whether the output voltage value and/or the current value of the transformer are abnormal, and if the temperature abnormality in the transformer is caused by the overload of the transformer, controlling the transformer to give an overload alarm prompt by a control device and enabling a worker to carry out load reduction operation on the transformer. If the abnormal temperature in the transformer is judged to be caused by the transformer fault, a transformer fault detection program is executed, and the specific fault part and fault type of the transformer are detected, so that maintenance personnel can repair and replace the transformer in a targeted manner, the workload of the maintenance personnel is reduced, and the power operation, maintenance and management efficiency is improved.
Step S2: and judging whether the transformer fault is in the winding or not through the second operation parameter of the transformer.
The second operation parameter comprises the internal temperature of the transformer and the vibration signal information of the transformer.
When the temperature abnormality of the transformer is judged not to be caused by overload in the step S1, the temperature inside the transformer needs to be further detected again, and if the transformer is moderately overheated, whether the transformer fault is caused by winding abnormality needs to be further judged according to vibration information of the transformer.
The vibration of the transformer body is mainly caused by the vibration of the transformer body and the vibration of the cooling device. The basic vibration frequency caused by the cooling device is lower and is obviously different from the vibration of the transformer body; the transformer body vibration includes vibration of the core and the winding. After the transformer is electrified and operated, current flows in the winding, and an electromagnetic field is generated in the iron core and the winding; the iron core silicon steel sheet material is subjected to magnetostriction under the action of a magnetic field, namely the size of atoms is subjected to micro deformation, so that the iron core vibrates. The vibration of the windings is caused by the interaction of currents in the windings under the influence of leakage inductance to generate electromotive force, which is proportional to the square of the current. The current of the winding is zero when the transformer is in no load, the winding basically has no influence on the vibration of the iron core, and the vibration of the transformer mainly depends on the iron core.
When it is detected in step S2 that the transformer fault may belong to a winding fault, further determination of the fault location and fault type is required. Specifically, when the transformer enters a winding fault verification program, whether the fault of the transformer is a winding fault is judged by judging whether the leakage reactance parameter after the short circuit of the transformer is within a preset value range.
And step S3: and the winding fault verification program is used for verifying whether the fault really occurs in the winding, if so, the S5 iron core fault type detection is executed, if not, the transformer fault is a fault of other parts except the iron core and the winding, and a shutdown inspection alarm prompt is given to require shutdown inspection.
Under the condition of a certain working frequency, the value of the leakage reactance parameter of the transformer is determined by the structure of a transformer winding, for a transformer, when the winding of the transformer is in a normal state, namely when the winding of the transformer does not have faults such as deformation or displacement, the value of the leakage reactance parameter after short circuit of the transformer is in a fixed value, and when the winding of the transformer is in a fault state, namely when the winding of the transformer has faults such as certain deformation or displacement, the value of the leakage reactance parameter after short circuit of the transformer is in another fixed value range, therefore, when detecting whether the winding of the transformer has faults, whether the winding of the transformer has faults can be judged by measuring the value of the leakage reactance parameter after short circuit of the transformer.
And step S4: detecting the type of winding fault; and judging the type of the winding fault through the analysis of the internal temperature of the transformer, the oil temperature and the oil pressure of the transformer and the vibration signal.
When it is determined in step S3 that the fault determination of the transformer is caused by a winding fault, the type of the winding fault is further determined through analysis of the temperature, oil pressure, and vibration signal of the transformer. Common types of winding faults include winding insulation aging faults, winding deformation faults, and the like.
And when the oil temperature or the oil pressure of the transformer continuously rises, judging that the insulation aging of the winding of the transformer occurs. And meanwhile, when the internal temperature of the transformer is overheated, whether the winding deformation fault occurs or not is analyzed through a transformer vibration signal.
Step S5: and when the transformer vibration information is judged to be the iron core fault, detecting the type of the iron core fault.
When the step S3 determines that the fault of the transformer is caused by the non-winding fault, it may be an iron core fault, and step S5 is executed to further determine the type of the iron core fault according to the working state of the transformer iron core. Common types of core faults include a core short fault and a core loose fault. And when the short circuit between the iron core frames occurs, judging the short circuit fault of the iron core, and when the difference between the vibration information of the iron core and the preset value is larger, judging the loosening fault of the iron core.
The transformer fault detection method provided by the embodiment can not only accurately detect whether the transformer runs abnormally or fails, but also prompt maintenance personnel to adjust the load of the transformer in time, so that the transformer is prevented from being burnt down due to long-time overload. Meanwhile, the fault type and the specific position of the fault of the transformer can be judged, particularly for a box-type transformer with a large size, whether the short-circuit fault of the iron core occurs or not can be accurately detected, maintenance personnel can repair and replace the transformer in a targeted manner, the workload of the maintenance personnel is reduced, and the power operation, maintenance and management efficiency is improved.
Example 2
The present embodiment further defines the transformer fault detection method based on embodiment 1. Specifically, the method comprises the following steps:
step S11: the starting transformer starts to operate.
Step S12: after the running time of the transformer reaches a first preset time, the detection device starts to detect the internal temperature T of the transformer.
Wherein the first predetermined time is determined according to the time from the startup of the transformer to the reaching of the stable operation state. When the running time of the transformer is less than the first preset time, the transformer does not enter a normal running state, and the detected internal temperature of the transformer is low, so that the judgment result is influenced. Therefore, the internal temperature of the transformer needs to be detected by the temperature measurement sensing system after the running time of the transformer reaches the first preset time, so that the internal temperature of the transformer is not too low, the judgment result is influenced, and the transformer is not burnt down due to too high temperature.
The temperature measurement sensing system is arranged on the temperature processing module on the outer wall of the transformer body and extends into the infrared temperature measurement sensor inside the transformer body. The infrared ray that infrared temperature sensor sent carries out non-contact continuous scanning temperature measurement to transformer winding and transformer core in the transformer body, and the temperature processing module is handled the calculation with the temperature signal that infrared temperature sensor transmitted to temperature processing module simultaneously with the temperature signal transmission that will detect to give controlling means with the result.
Step S13: judging whether the internal temperature T of the transformer detected by the temperature measurement sensing system is within a first preset temperature range delta T1 or not, and if so, continuing normal operation of the transformer; if the determination result is negative, step S14 is executed.
The first preset temperature range delta T1 is set according to the temperature values of the winding and the iron core when the transformer does not have faults and operates normally.
Step S14: and executing a fault early warning detection program at the moment, warning workers to closely monitor the running condition of the transformer and detecting the output voltage of the transformer.
Step S15: judging whether the output voltage is in a voltage range preset by the transformer, and executing an S2 fault judgment program when the judgment result is yes; if the judgment result is no, the fact that the temperature inside the transformer exceeds the first preset temperature range is caused by overload of the transformer is indicated, and at this time, step S16 is executed to control the load reduction operation of the transformer.
Step S16: regulating the transformer to reduce its capacity and current limit I max . I.e. to limit the operation of the transformer not to exceed the current limit I max 。
Through the above series of judgments, the possibility of transformer faults is discharged to a certain extent, the transformer load is reduced, the service life of the transformer is prolonged, on the other hand, the follow-up fault detection is also facilitated, and the detection accuracy is improved.
Step S21: detecting the internal temperature T of the transformer again;
step S22: judging whether the internal temperature T of the transformer is within a second preset temperature range delta T or not 2 If yes, indicating that the interior of the transformer is moderately overheated, and executing step S23; if the determination result is negative, step S14 is executed.
Step S23: sampling vibration information of the transformer according to set sampling frequency and sampling time, intercepting a vibration signal of the transformer in a whole period, performing wavelet denoising on the intercepted vibration signal, performing Fourier spectrum analysis, and simultaneously solving component amplitudes of 50Hz, 150Hz, 100Hz and 200Hz of the vibration signal. And simultaneously, the oil temperature and the oil pressure of the transformer are continuously detected, and detected signals are sent to the control device.
Step S24: judging whether the amplitude of the frequency spectrum component of 100Hz is larger than a first preset threshold value phi or not 1 If yes, judging that the fault of the transformer is possibleIf the result of the determination is negative, the other part except the winding has a fault, such as an iron core fault, and step S5 needs to be executed to further detect whether the part is an iron core fault.
Analysis and calculation show that in vibration signal frequency spectrums in various iron core fault states, the sum of the amplitude values of 100Hz components is higher than that of the 100Hz components under normal conditions, and the difference is positively correlated with the fault degree, namely the more serious the iron core fault is, the larger the difference between the two is.
The first preset threshold value phi 1 And setting according to vibration information of the corresponding frequency spectrum of the transformer under a fault-free and normal working state.
In the step, whether the fault of the transformer is a winding fault or not is accurately judged through orderly detection of the temperature and the vibration signals, a basis is provided for a next verification procedure, and the maintenance is convenient for workers.
The winding fault verification procedure S3 includes:
step S31: and acquiring the leakage reactance parameters after the short circuit of the transformer.
Under the condition of a certain working frequency, the value of the leakage reactance parameter of the transformer is determined by the structure of a transformer winding, for a transformer, when the winding of the transformer is in a normal state, namely when the winding of the transformer does not have faults such as deformation or displacement, the value of the leakage reactance parameter after short circuit of the transformer is in a fixed value, and when the winding of the transformer is in a fault state, namely when the winding of the transformer has faults such as deformation or displacement, the value of the leakage reactance parameter after short circuit of the transformer is in another fixed value range.
Further, the transformer leakage reactance parameters are obtained through the leakage reactance parameters of the simulation transformer under the same conditions, and the simulation transformer is set according to the size, the structure and the performance parameters of the simulated actual transformer, so that the leakage reactance parameters obtained through the simulation transformer established by the simulation software can be used as the leakage reactance parameters of the simulated actual transformer.
Step S32: judging whether the leakage reactance parameter value obtained after the short circuit of the transformer is in a fault value range or not, if so, determining the fault of the transformer winding, executing the step S4, and judging the fault type of the specific transformer winding; if not, the transformer fault is a fault of other parts except the iron core and the winding, and a shutdown inspection alarm prompt is given, so that shutdown inspection is required.
Specifically, if the measured value of the leakage reactance parameter after the short circuit of the transformer is within the fault value range, judging that the winding of the transformer has a fault; on the contrary, if the value of the leakage reactance parameter after the short circuit of the transformer is measured is not in the fault value range, the winding of the transformer is not in the fault state, and the fault of the transformer can be judged to be the fault of other parts except the iron core and the winding.
Step S41: acquiring the oil temperature and oil pressure change curve of the transformer, judging whether the oil temperature or the oil pressure change curve of the transformer is in a continuously rising state, if so, judging that the transformer fault is a winding insulation aging fault, and giving an insulation aging alarm prompt. If not, it is determined that the transformer winding fault is not caused by insulation aging, and further determination is required, and step S42 is performed.
Step S42: the transformer internal temperature T is detected again.
Step S43: judging whether the internal temperature T is in a third preset temperature range delta T or not 3 If yes, indicating that the interior of the transformer is severely overheated, and executing step S44; if the judgment result is no, the transformer fault is the fault of other parts except the iron core and the winding, and the machine needs to be stopped for inspection.
Step S44: and detecting the vibration information of the transformer, and calculating the sum of the amplitudes of the spectral components at 100Hz and 200 Hz.
Step S45: judging whether the ratio of the sum of the amplitudes of the spectral components at 50Hz and 150Hz to the sum of the amplitudes of the spectral components at 100Hz and 200Hz is larger than a second preset threshold phi 2 If the fault is the winding deformation fault, the transformer fault is judged to be the fault of other parts except the iron core and the winding, and the machine needs to be stopped for inspection.
In the vibration signal frequency spectrum under the deformation fault state of various windings, the ratio of the sum of the frequency spectrum component amplitudes of 50Hz and 150Hz and the sum of the frequency spectrum component amplitudes of 100Hz and 200Hz is higher than the ratio of the sum of the frequency spectrum component amplitudes of 50Hz and 150Hz and the sum of the frequency spectrum component amplitudes of 100Hz and 200Hz in the normal state, and the difference is positively correlated with the fault degree, namely the more serious the winding deformation is, the larger the difference between the two is.
The iron core fault type detection program comprises the following steps:
s51: and measuring the insulation resistance between the iron core frames.
S52: and judging whether the iron core frames are short-circuited, if so, judging that the iron core is short-circuited, otherwise, executing S53, and further detecting the type of the iron core fault.
Further, the insulation resistance between the iron core frames is measured by a resistance measuring device, and the resistance measuring device is a multimeter or a megohmmeter.
S53: and detecting the vibration information of the transformer, and calculating the sum of the amplitudes of the frequency spectrum components of 50Hz and 150 Hz.
S54: and judging whether the sum of the frequency spectrum component amplitudes of 50Hz and 150Hz is greater than a third preset threshold value phi 3, if so, judging that the fault of the iron core is a loosening fault, otherwise, indicating that the fault of the transformer is a fault of other parts except the iron core and the winding, and needing to be stopped for inspection.
After the iron core becomes flexible, the magnetic leakage grow between silicon steel sheet seam crossing and the lamination leads to electromagnetic attraction grow, and the iron core vibrates the grow. Wherein the sum of the magnitudes of the spectral components at 50Hz and 150Hz is equal to a third predetermined threshold value phi 3 The difference of (a) and (b) is positively correlated with the fault degree, i.e. the more severe the iron core is loosened, the larger the difference between the two is.
According to the fault detection method for the box-type transformer, through one-by-one multi-stage detection of a plurality of parameters, the fault of the transformer is accurately judged, and a corresponding alarm prompt is made in time, so that a good prevention effect is achieved on the transformer without the fault, and the fault probability is reduced; the fault position and type of the transformer which has a fault can be timely and accurately judged, particularly, the fault of iron core short circuit and iron core looseness of a box-type transformer with a large size can be accurately detected, maintenance personnel can repair and replace the transformer in a targeted manner, the workload of the maintenance personnel is reduced, and the power operation, maintenance and management efficiency is improved.
Example 3
As an embodiment of the present invention, this embodiment further provides a fault detection system for a box-type transformer. The transformer comprises a box body, a transformer body and a detection system, wherein the transformer body comprises a transformer winding, a transformer iron core and a cooling device, and cooling oil is stored in the cooling device. For the box-type transformer with larger iron core size, in order to facilitate the heat dissipation inside the iron core and fully reduce the eddy current loss and the like, the cooling device is arranged between the silicon steel sheet laminations forming the iron core, and the iron core is divided into a plurality of iron core frames through the cooling device. In the lamination process of the transformer core, the silicon steel sheets on two sides of the cooling device may be short-circuited, so that the short circuit between the core frames is caused.
The detection system comprises a control device, an analysis module, a timer and a detection device, wherein the timer is used for timing and analyzing the running time of the transformer, on one hand, the timer is used for prompting the fatigue state of the transformer, and on the other hand, the transformer is enabled to execute a detection program according to preset time.
The detection device feeds detected data parameters back to the analysis module, the analysis module analyzes and calculates the detected data and then transmits the data to the control device, and the control device controls the alarm device to give corresponding alarm prompts.
Furthermore, the detection device comprises a temperature measurement sensing system, wherein the temperature measurement sensing system comprises a temperature processing module arranged on the outer wall of the transformer body and an infrared temperature measurement sensor extending into the transformer body. The infrared temperature measuring sensor is connected with the temperature processing module, and the temperature processing module is connected with the control device. The sensor probe of the infrared temperature measurement sensor carries out non-contact continuous scanning temperature measurement on the interior of the transformer and transmits a measured temperature signal to the temperature processing module, and the temperature processing module analyzes and processes the received temperature signal and then transmits the processed temperature signal to the control device.
Furthermore, the detection device further comprises a vibration information detection device, the vibration information detection device is a vibration sensor, the vibration sensor is arranged right above the middle position between the high-voltage winding and the low-voltage winding in the transformer, and preferably, the vibration sensors are arranged in a plurality. The vibration information detection device is connected with the analysis module, and the analysis module analyzes and calculates the received vibration confidence and transmits the result to the control device.
Furthermore, the detection device further comprises a leakage reactance parameter measurement system, and the leakage reactance parameter measurement system comprises simulation software and a simulation transformer.
Further, the detection device further comprises a resistance measuring device, and the resistance measuring device is a universal meter or a megaohm meter.
The fault detection system for the box-type transformer can accurately detect data parameters of the transformer in various states, timely and accurately analyze and synthesize the parameters, provide basis for a detection method of the transformer, guarantee detection flow smoothness, and facilitate maintenance personnel to repair and replace the transformer in a targeted manner.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (5)
1. A transformer fault detection method is characterized in that whether a tested transformer is in fault or not is judged based on a preset fault numerical value range and a normal numerical value range, and the method comprises the following steps:
step S1: judging whether the running state of the transformer is abnormal or not according to the first running parameter of the transformer, and controlling and adjusting the running state;
step S2: judging whether the transformer fault is in the winding or not according to the second operation parameter of the transformer;
and step S3: a winding fault verification program for verifying whether a fault has actually occurred in the winding;
and step S4: detecting the type of winding fault; judging the type of winding faults through the analysis of the internal temperature, the oil temperature and the oil pressure of the transformer and vibration signals;
step S5: when the transformer vibration information is judged to be an iron core fault, detecting the type of the iron core fault;
the step S1 includes:
step S11: starting the transformer to start running;
step S12: after the running time of the transformer reaches a first preset time, the detection device starts to detect the internal temperature T of the transformer;
step S13: judging whether the internal temperature T of the transformer detected by the temperature measurement sensing system is within a first preset temperature range delta T1 or not, and if so, continuing normal operation of the transformer; if the judgment result is no, executing the step S14;
step S14: executing a fault early warning detection program, warning workers to closely monitor the running condition of the transformer and detecting the output voltage of the transformer;
step S15: judging whether the output voltage is in a voltage range preset by the transformer, and executing an S2 fault judgment program when the judgment result is yes; if the judgment result is negative, the fact that the temperature inside the transformer exceeds the first preset temperature range is caused by overload of the transformer is indicated, and step S15 is executed to control the load reduction operation of the transformer;
step S16: regulating transformer to reduce capacity and current limit I max (ii) a I.e. limiting the operation of the transformer to not exceed the current limit I max ；
The step S2 includes:
step S21: detecting the internal temperature T of the transformer again;
step S22: judging whether the internal temperature T of the transformer is within a second preset temperature range delta T 2 If yes, indicating that the interior of the transformer is moderately overheated, and executing step S23; if the judgment result is no, executing the step S14;
step S23: sampling vibration information of the transformer according to set sampling frequency and sampling time, intercepting a vibration signal of the transformer in a whole period, performing wavelet noise reduction on the intercepted vibration signal, performing Fourier spectrum analysis, simultaneously solving component amplitudes of the vibration signal at 50Hz, 150Hz, 100Hz and 200Hz, simultaneously continuously detecting oil temperature and oil pressure of the transformer, and sending the detected signal to a control device;
step S24: judging whether the amplitude of the frequency spectrum component of 100Hz is greater than a first preset threshold value of 9811 1 If yes, a winding fault verification program S3 needs to be further executed, if the judgment result is no, faults of other parts except the winding need to be executed, and a step S5 needs to be executed to further detect whether the faults are iron core faults;
the step S3 includes:
step S31: acquiring leakage reactance parameters after the short circuit of the transformer;
step S32: judging whether the obtained leakage reactance parameter value after the short circuit of the transformer is in a fault value range or not, if so, judging the fault of the transformer winding, executing the step S4, and judging the fault type of the specific transformer winding; if not, the transformer fault is indicated to be a fault of other parts except the iron core and the winding, and a shutdown inspection alarm prompt is given, so that shutdown inspection is required;
the step S4 includes:
step S41: acquiring the oil temperature and oil pressure change curve of the transformer, judging whether the oil temperature or the oil pressure change curve of the transformer is in a continuously rising state, if so, judging that the transformer fault is a winding insulation aging fault, and giving an insulation aging alarm prompt, otherwise, judging that the transformer winding fault is not caused by insulation aging and needs to be further judged, and executing a step S42;
step S42: detecting the internal temperature T of the transformer again;
step S43: judging whether the internal temperature is in a third preset temperature range delta T 3 If yes, indicating that the interior of the transformer is severely overheated, and executing step S44; if the judgment result is negative, the transformer fault is a fault of other parts except the iron core and the winding, and the machine needs to be stopped for inspection;
step S44: detecting vibration information of the transformer, and calculating the sum of the frequency spectrum component amplitudes of 100Hz and 200 Hz;
step S45: judging whether the ratio of the sum of the amplitudes of the spectral components at 50Hz and 150Hz to the sum of the amplitudes of the spectral components at 100Hz and 200Hz is largeAt a second predetermined threshold value of 9811 2 If so, judging that the transformer fault is a winding deformation fault, otherwise, judging that the transformer fault is a fault of other parts except the iron core and the winding, and needing to be stopped for inspection;
in the vibration signal frequency spectrum in the winding deformation fault state, the ratio of the sum of the frequency spectrum component amplitudes of 50Hz and 150Hz and the sum of the frequency spectrum component amplitudes of 100Hz and 200Hz is higher than the ratio of the sum of the frequency spectrum component amplitudes of 50Hz and 150Hz and the sum of the frequency spectrum component amplitudes of 100Hz and 200Hz in the normal state, and the difference is positively correlated with the fault degree, namely the more serious the winding deformation is, the larger the difference is;
the step S5 includes the following steps:
s51: measuring the insulation resistance between the iron core frames;
s52: judging whether the iron core frames are short-circuited, if so, judging that the iron core is short-circuited, otherwise, executing S53, and further detecting the type of the iron core fault;
further, the insulation resistance between the iron core frames is measured by a resistance measuring device, and the resistance measuring device is a universal meter or a megohmmeter;
s53: detecting vibration information of the transformer, and calculating the sum of the frequency spectrum component amplitudes of 50Hz and 150 Hz;
s54: judging whether the sum of the amplitudes of the frequency spectrum components of 50Hz and 150Hz is greater than a third preset threshold value of 9811 3 If so, judging that the iron core fault is a loosening fault, otherwise, indicating that the transformer fault is a fault of other parts except the iron core and the winding and needing to be stopped for inspection;
after the iron core becomes flexible, magnetic leakage between the silicon steel sheet seam and the lamination becomes big, resulting in that electromagnetic attraction becomes big, and iron core vibration becomes big, wherein the difference and the fault degree positive correlation of the frequency spectrum component amplitude sum of 50Hz and 150Hz and third preset threshold phi 3, and the iron core becomes flexible more seriously promptly, and both differences are big more.
2. The transformer fault detection method according to claim 1, wherein the first operation parameter comprises a transformer internal temperature, an output current and/or an output voltage, and the second operation parameter comprises a transformer internal temperature, transformer vibration signal information.
3. The transformer fault detection method according to claim 2, wherein the temperature inside the transformer is detected by a temperature measurement sensing system, and the temperature measurement sensing system comprises a temperature processing module mounted on the outer wall of the transformer body and an infrared temperature measurement sensor extending into the transformer body.
4. A box-type transformer, characterized in that, the transformer fault detection method of any claim 1 to 3 is used, the box-type transformer comprises a box body, a transformer body and a detection system, the transformer body comprises a transformer winding, a transformer core and a cooling device, cooling oil is stored in the cooling device, the detection system comprises a control device, an analysis module, a timer and a detection device, the timer carries out timing analysis on the running time of the transformer, the detection device feeds back the detected data parameters to the analysis module, the analysis module carries out analysis calculation on the detected data and then transmits the data to the control device, and the control device controls the alarm device to give corresponding alarm prompt.
5. The box-type transformer according to claim 4, characterized in that the detection device comprises a temperature measurement sensing system, a vibration information detection device and a leakage reactance parameter measurement system, the temperature measurement sensing system comprises a temperature processing module installed on the outer wall of the transformer body and an infrared temperature measurement sensor extending into the transformer body, the vibration information detection device is arranged as a vibration sensor, the vibration sensor is arranged right above the middle position between the high-voltage winding and the low-voltage winding in the transformer, and the leakage reactance parameter measurement system comprises simulation software and a simulation transformer.
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| CN113176522A (en) * | 2021-04-16 | 2021-07-27 | 国网江苏省电力有限公司南通供电分公司 | Transformer short-circuit fault detection method |
| CN113405446B (en) * | 2021-05-11 | 2023-08-08 | 联合汽车电子有限公司 | Method and device for detecting gap of magnetic core of transformer |
| CN115394546B (en) * | 2022-10-27 | 2023-01-06 | 山东晨宇电气股份有限公司 | Offshore wind power test transformer |
| CN116068322A (en) * | 2023-03-07 | 2023-05-05 | 常州太平洋电力设备(集团)有限公司 | Method, system and server for online monitoring of comprehensive parameters of coiled core transformer |
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