CN109932594B - Method and apparatus for fault detection of electrical equipment - Google Patents
Method and apparatus for fault detection of electrical equipment Download PDFInfo
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- CN109932594B CN109932594B CN201910199961.2A CN201910199961A CN109932594B CN 109932594 B CN109932594 B CN 109932594B CN 201910199961 A CN201910199961 A CN 201910199961A CN 109932594 B CN109932594 B CN 109932594B
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Abstract
The invention relates to a method and a device for fault detection of power equipment, wherein the method comprises the following steps: acquiring respective first temperature rises of a group of same-attribute contact points on three phases of power equipment, wherein each group of same-attribute contact points are three contact points corresponding to the same position in the power equipment; determining a target temperature rise from each of the first temperature rises; correcting the target temperature rise to obtain a second corrected temperature rise; and determining whether the contact point with the same attribute has a fault according to the second temperature rise. According to the invention, the temperature rise of each phase of a group of contact points with the same attribute is transversely compared to determine which phase of the contact point has a fault, and the temperature rise to be compared is corrected before comparison so as to enable the judgment result to be more accurate, so that the comparison is quicker, more convenient and better in accuracy.
Description
Technical Field
The utility model discloses the electric power system field, especially be used for the method and the device of the fault detection of power equipment.
Background
The switch cabinet is an important power transmission and distribution device in an electric power system, so that the operation condition of the switch cabinet needs to be monitored in real time. The switch cabinet generally has various contact points, such as the position where the tulip contact is contacted with the fixed contact, the position where the copper bar is connected with the external device, and the like, and when current flows through the contact points, the contact points generate heat, so that the maximum allowable heat-generating temperature and the maximum allowable temperature rise of the contact points are specified in the national standard. Due to factors such as manufacturing, installation, transportation or long-term operation, the contact points may be oxidized, deformed and loosened, and when the problems occur, the temperature rise of the contact points exceeds a specified range, so that the switch cabinet is damaged. To avoid these problems, it is often necessary to monitor the temperature rise of the contacts on-line. Specifically, when the actual temperature rise is found to exceed the maximum allowable temperature rise, it is determined that the contact point is malfunctioning. The temperature rise here refers to the difference between the temperature of the contact point and the ambient temperature, which is generally obtained by means of a temperature probe placed in the environment.
Because the temperature or the temperature rise generated by the switch cabinet under different loads is not fixed, whether the contact point has a fault or not is judged by adopting the uniform maximum allowable heating temperature and the allowable temperature rise, and the situation of false alarm is possible.
Disclosure of Invention
In view of the above, the present invention provides a method for fault detection of an electrical device, comprising:
acquiring respective first temperature rises of a group of same-attribute contact points on three phases of power equipment, wherein each group of same-attribute contact points are three contact points corresponding to the same position in the power equipment;
determining a target temperature rise from each of said first temperature rises;
correcting the target temperature rise to obtain a corrected second temperature rise;
and determining whether the same-attribute contact point fails or not according to the second temperature rise.
The temperature rise of each phase of a group of contact points with the same attribute is transversely compared to determine which phase of the contact point fails, and the temperature rise to be compared is corrected before comparison so that the judgment result is more accurate.
According to the method as described above, optionally, determining a target temperature rise from each of the first temperature rises comprises determining the largest one of the first temperature rises as the target temperature rise. The largest one is selected as the target temperature rise, so that the calculation amount can be simplified.
According to the method, optionally, the correcting the target temperature rise, and obtaining a corrected second temperature rise includes:
selecting a larger one of the two remaining first temperature rises as a reference temperature rise;
obtaining the corrected second temperature rise delta K according to the following formulaCm：
Wherein, Δ KCTo represent the target temperature rise, ICPrimary current, I, of a contact point of the same attribute corresponding to the target temperature riseBAnd representing the primary current of the contact point with the same attribute corresponding to the reference temperature rise.
Although the phase currents at the same location do not differ much, there is in fact some imbalance. In order to eliminate the effect of such an imbalance on each homographic contact point, the target temperature rise needs to be corrected.
According to the method as described above, optionally, the primary current is an average value of the primary current in the current sampling period. Because the primary current may change in real time, the average value of the primary current in a sampling period is used as the primary current of the power equipment in the period, and the accurate value of the primary current can be obtained as much as possible.
According to the method described above, optionally, determining whether the homonymous contact point fails according to the second temperature rise includes:
comparing the second temperature rise with the reference temperature rise, and determining that the smaller one of the second temperature rise and the reference temperature rise is a third temperature rise and the larger one is a fourth temperature rise;
and if the fourth temperature rise is greater than the sum of the third temperature rise and a first preset factor and the fourth temperature rise is greater than the product of the third temperature rise and a second preset factor, determining that the contact point with the same attribute corresponding to the fourth temperature rise has a fault.
The result thus determined is relatively accurate.
According to the method, optionally, acquiring the respective first temperature rises of the three phases of the power equipment corresponding to the attribute contact point comprises:
acquiring a fifth temperature rise of a contact point of an electric device at the beginning of an initial sampling period and a sixth temperature rise at the end of the initial sampling period, wherein the contact point is a contact position of at least two components of the electric device;
acquiring a time constant of a first-order inertia system of the power equipment;
predicting a first temperature rise of the contact point at the end of an Xth sampling period according to the fifth temperature rise, the sixth temperature rise and the time constant, wherein L is a positive integer and is more than or equal to 3, s is one sampling period, and N is the time constant.
By acquiring the temperature rises at the beginning and the end of a sampling period and predicting the temperature after the preset time period, the temperature rise after the preset time period can be quickly determined, for example, the value after the temperature rise is stable is used as the first temperature rise, and then subsequent operations, for example, whether the contact point with the same attribute has a fault in the foregoing embodiment, are executed through the predicted temperature rise.
According to the method as described above, optionally, predicting the first temperature rise of the contact point at the end of the xth sampling period according to the fifth temperature rise, the sixth temperature rise and the time constant comprises:
determining a first temperature rise T of the contact point according to the following formula:
T＝(ΔKn-ΔKn-1*e-1/N)/(1-e-1/N)
wherein, Δ Kn-1For the fifth temperature rise, Δ KnThe sixth temperature rise.
The present invention also provides an apparatus for fault detection of electrical equipment, comprising:
the system comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for acquiring respective first temperature rises of a group of same-attribute contact points on three phases of power equipment, and each group of same-attribute contact points are three contact points corresponding to the same position in the power equipment;
a first determining unit for determining a target temperature rise from among the first temperature rises;
the correcting unit is used for correcting the target temperature rise to obtain a corrected second temperature rise;
and a second determining unit for determining whether the homonymous contact point has a failure or not according to the second temperature rise.
The temperature rise of each phase of a group of contact points with the same attribute is transversely compared to determine which phase of the contact point fails, and the temperature rise to be compared is corrected before comparison so that the judgment result is more accurate.
According to the apparatus as described above, optionally, the first determining unit is specifically configured to: the largest one of the first temperature rises is determined as the target temperature rise. The largest one is selected as the target temperature rise, so that the calculation amount can be simplified.
According to the apparatus as described above, optionally, the correction unit is specifically configured to:
selecting a larger one of the two remaining first temperature rises as a reference temperature rise;
obtaining the corrected second temperature rise delta K according to the following formulaCm：
Wherein, Δ KCTo represent the target temperature rise, ICPrimary current, I, of a contact point of the same attribute corresponding to the target temperature riseBAnd representing the primary current of the contact point with the same attribute corresponding to the reference temperature rise.
Although the phase currents at the same location do not differ much, there is in fact some imbalance. In order to eliminate the effect of such an imbalance on each homographic contact point, the target temperature rise needs to be corrected.
According to the apparatus as described above, optionally, the primary current is an average value of the primary current in the current sampling period. Because the primary current may change in real time, the average value of the primary current in a sampling period is used as the primary current of the power equipment in the period, and the accurate value of the primary current can be obtained as much as possible.
According to the apparatus as described above, optionally, the second determining unit is specifically configured to:
comparing the second temperature rise with the reference temperature rise, and determining that the smaller one of the second temperature rise and the reference temperature rise is a third temperature rise and the larger one is a fourth temperature rise;
and if the fourth temperature rise is greater than the sum of the third temperature rise and a first preset factor and the fourth temperature rise is greater than the product of the third temperature rise and a second preset factor, determining that the contact point with the same attribute corresponding to the fourth temperature rise has a fault.
The result thus determined is relatively accurate.
According to the apparatus as described above, optionally, the obtaining unit specifically includes:
a first obtaining subunit, configured to obtain a fifth temperature rise at a start time and a sixth temperature rise at an end time of a contact point of an electrical device at the start of an initial sampling period, where the contact point is a contact position of at least two components of the electrical device;
a second acquisition subunit, configured to acquire a time constant of a first-order inertial system of the electrical device;
and a prediction subunit, configured to predict, according to the fifth temperature rise, the sixth temperature rise, and the time constant, a first temperature rise of the contact point at the end of an xth sampling period, where L is a positive integer and L is greater than or equal to 3, s is one sampling period, and N is the time constant.
By acquiring the temperature rises at the beginning and the end of a sampling period and predicting the temperature after the preset time period, the temperature rise after the preset time period can be quickly determined, for example, the value after the temperature rise is stable is used as the first temperature rise, and then subsequent operations, for example, whether the contact point with the same attribute has a fault in the foregoing embodiment, are executed through the predicted temperature rise.
According to the apparatus as described above, optionally, the predictor unit is specifically configured to:
determining a first temperature rise T of the contact point according to the following formula:
T＝(ΔKn-ΔKn-1*e-1/N)/(1-e-1/N)
wherein, Δ Kn-1For the fifth temperature rise, Δ KnThe sixth temperature rise.
The present invention further provides an apparatus for fault detection of electrical equipment, comprising:
at least one memory for storing instructions;
at least one processor configured to perform any of the aforementioned methods for fault detection of a power device according to instructions stored by the memory.
The invention further provides a readable storage medium having stored therein machine readable instructions which, when executed by a machine, perform a method for fault detection of an electrical power device according to any preceding claim.
Drawings
The foregoing and other features and advantages of the invention will become more apparent to those skilled in the art to which the invention relates upon consideration of the following detailed description of a preferred embodiment of the invention with reference to the accompanying drawings, in which:
fig. 1 is a flow chart illustrating a method for fault detection of an electrical device according to an embodiment of the present invention.
Fig. 2 is a flow chart illustrating a method for fault detection of an electrical device according to another embodiment of the present invention.
Fig. 3 is a schematic structural diagram of an apparatus for fault detection of power equipment according to an embodiment of the present invention.
Fig. 4 is a schematic structural diagram of an apparatus for fault detection of power equipment according to another embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail by referring to the following examples.
The power equipment of the invention can be a switch cabinet or a transformer, and of course, can also be other equipment which can adopt the method of the invention. The contact point of the power device may be a contact position of two locations. The following description will specifically describe a switchgear as an example.
Switch cabinets are generally three-phase. There are three same-attribute contact points corresponding to the same position, and each contact point corresponds to a phase. The same position refers to the contact position of the same component with another component in the switchgear cabinet, which has three contact points, corresponding to three phases. If the three phases corresponding to the attribute contact points are in good contact and have no fault, the resistance and the thermal resistance of the three phases should be similar, and therefore, the temperature rise should also be similar. Therefore, it is possible to quickly determine which phase has a problem by comparing the temperature rise of the contact points with the property in the lateral direction.
Example one
The present embodiment provides a method for detecting a fault of a switch cabinet, where the main execution body is a device for detecting a fault of a switch cabinet, and the device may be integrated in a relay or may be disposed in a computer, and may also be disposed separately, which is not described herein again.
As shown in fig. 1, a method for fault detection of a switchgear according to the present embodiment includes:
The switch cabinets generally have three phases, each of which has at least one identical position. The same position is, for example, a contact position between a moving contact and a fixed contact of the circuit breaker, a contact position between a copper bar and a bushing, and the like, and is not described herein again. The contact position of the moving contact and the static contact corresponds to three phases, and the contact position of the copper bar and the sleeve corresponds to three phases. The same position in this embodiment represents the contact position of the same component with another component in the switchgear cabinet, which has three contact points, corresponding to three phases. Three contact points at the same location are collectively referred to as a set of same attribute contact points.
Since the same-property contact points are located at the same position in the switchgear cabinet, the corresponding temperature rises should generally be the same. Therefore, the invention judges which contact point with the same attribute has a fault by comparing the respective first temperature rises of the contact points with the same attribute.
The temperature rise of the present embodiment refers to a difference between the temperature value of the contact point and the ambient temperature.
A target temperature rise is determined from the first temperature rises, step 102.
The target temperature rise may be determined according to actual needs, for example, one of the target temperature rises may be randomly selected, or one of the target temperature rises having the largest median value may be selected as the target temperature rise, which is not described herein again. The target temperature rise is a first temperature rise corresponding to one of a set of like-attribute contact points, i.e., one of three first temperature rises.
It is of course also possible to normalize each first temperature rise according to the primary current, for example, on the basis of one of the first temperature rises, perform a normalization operation on the remaining two first temperature rises, and then determine a target temperature rise from the normalized first temperature rises, for example, the one with the largest value as the target temperature rise.
And 103, correcting the target temperature rise to obtain a corrected second temperature rise.
Although the phase currents at the same location do not differ much, there is in fact some imbalance. In order to eliminate the effect of such an imbalance on each homographic contact point, the target temperature rise needs to be corrected. The correction modes are many, for example, the average value of the currents of the three contact points with the same attribute is taken, and the target temperature rise can be corrected in a fitting mode, which is not described herein again.
And step 104, determining whether the contact point with the same attribute has a fault according to the second temperature rise.
For example, if the second temperature rise exceeds a preset threshold, it may be determined that the contact corresponding to the target is faulty.
Because the loads applied to a switch cabinet may be different, the loads correspond to different working currents, and if a uniform preset threshold value is adopted, the situation that a contact point has a fault but is not judged is likely to occur. Therefore, whether the contact point is failed or not can be judged in the following way:
comparing the second temperature rise with the reference temperature rise, and determining that the smaller one of the second temperature rise and the reference temperature rise is the third temperature rise and the larger one is the fourth temperature rise;
and if the fourth temperature rise is greater than the sum of the third temperature rise and a first preset factor and the fourth temperature rise is greater than the product of the third temperature rise and a second preset factor, determining that the same-attribute contact point corresponding to the fourth temperature rise has a fault.
For example, if the second temperature rise is compared with the reference temperature rise, the second temperature rise is found to be a smaller one as the third temperature rise, and the reference temperature rise is found to be a larger one as the fourth temperature rise.
The fourth temperature rise is larger than the sum of the third temperature rise and a first preset factor, and the difference value between the fourth temperature rise and the third temperature rise is larger than the first preset factor, so that the same-attribute contact point corresponding to the fourth temperature rise is likely to fail. Since the temperature rise between the phases is large even in a normal contact state when the primary current is large, further verification is required. The fourth temperature rise is greater than the third temperature rise multiplied by a first second predetermined factor, which means that the fourth temperature rise is proportionally greater than the third temperature rise. Therefore, when the two conditions are met, the fact that the contact point with the same attribute corresponding to the fourth temperature rise is in fault can be determined, and the determined result is accurate.
According to the embodiment, the temperature rise of each phase of a group of contact points with the same attribute is transversely compared to determine which phase of the contact point fails, and the temperature rise to be compared is corrected before comparison so that the judgment result is more accurate, and the comparison is quicker, more convenient and better in accuracy.
Example two
The present embodiment further provides a supplementary description of the method for detecting a fault of a switchgear according to the first embodiment.
Fig. 2 is a schematic flow chart of a method for fault detection of a switchgear according to the present embodiment. The method comprises the following steps:
This step is identical to step 101 and will not be described herein.
In step 202, the largest one of the first temperature rises is determined as the target temperature rise.
In this embodiment, the one having the largest of the three first temperature rises is taken as the target temperature rise. If one of the three contacts in a set of contacts with the same attribute fails, then the most likely contact is the one with the largest temperature rise. The largest one is selected as the target temperature rise, so that the calculation amount can be simplified.
In step 203, a larger one of the two remaining first temperature rises is selected as a reference temperature rise.
In step 202, the smallest of the first median temperature rises may be excluded first. This is because the temperature rise is high due to poor contact, and the smallest one of the first temperature rises, that is, the one with less possibility of failure is excluded first, so as to simplify the algorithm.
Of course, step 202 may be performed first, and then step 203 may be performed. For example, the maximum two of the three first temperature rises may be selected first, and then the larger one of the maximum two temperature rises may be selected as the target temperature rise, and the smaller one may be selected as the reference temperature rise. Specifically, how to select the target temperature rise and the reference temperature rise does not have a sequence, and only the target temperature rise is the largest one of the three first temperature rises, and the reference temperature rise is the middle one of the three first temperature rises.
Wherein, Δ KCTo represent the target temperature rise, ICPrimary current, I, of a contact point of the same attribute corresponding to a target temperature riseBAnd representing the primary current of the contact point with the same attribute corresponding to the reference temperature rise.
The primary current here may be an average value of the primary current in the present sampling period. For example, step 201 and step 205 may be performed every other sampling period to continuously monitor whether any contact point with the attribute has failed. The primary current can be the average value of the primary current in the current period, and as the primary current is likely to change in real time, the average value of the primary current in a sampling period is used as the primary current of the switch cabinet in the period, so that the accurate value of the primary current can be obtained as much as possible.
And step 205, determining whether the contact point with the same attribute has a fault according to the second temperature rise.
Step 205 is identical to step 104 and will not be described herein.
According to the embodiment, the whole algorithm can be simplified by eliminating the first temperature rise with the minimum value, the first temperature rise with the maximum value is corrected through the first temperature rise with the middle value, the temperature rise difference between three phases caused by current imbalance can be eliminated as much as possible, and the judgment result is more accurate. By transversely comparing the three temperature rises corresponding to a group of contact points with the same attribute, the defect caused by judging by adopting a uniform threshold value can be avoided.
EXAMPLE III
This embodiment further supplements the method of the previous embodiment. The present embodiment mainly provides a supplementary description on how to obtain the first temperature rises in the above embodiments, that is, the first temperature rises are based on the predicted temperature rise of the contact point.
In this embodiment, the obtaining of the respective first temperature rise of the three phases corresponding to the same attribute contact point of one switch cabinet in the foregoing embodiment includes:
a: acquiring a fifth temperature rise of a contact point of a switch cabinet at the beginning of an initial sampling period and a sixth temperature rise at the end of the initial sampling period, wherein the contact point is the contact position of at least two components of the switch cabinet;
b: acquiring a time constant of a first-order inertia system of a switch cabinet;
c: and predicting the first temperature rise of the contact point at the end of the Xth sampling period according to the fifth temperature rise, the sixth temperature rise and a time constant, wherein L is a positive integer and is more than or equal to 3, s is a sampling period, and N is a time constant.
The initial sampling period is a sampling period corresponding to the first temperature rise and the second temperature rise, and the initial sampling period is not necessarily the 1 st sampling period for actually sampling. The duration of the sampling period can be set according to actual needs, and is 20-30 minutes, for example. The first temperature rise can be regarded as a stable temperature rise corresponding to the contact point.
The first-order inertia system refers to the response relation between the primary current and the temperature rise. In general, if the primary current is constant and the sampling period reaches a time constant of 3-5 times, the temperature rise should reach almost a steady value. Of course, the primary current of all sampling periods within 8-9 hours can be sampled, and the sampling period can be determined according to actual needs. The time constant of this first order inertial system is known in advance from the parameters of the system, for example 100 minutes.
The step a and the step b have no execution sequence, and can be executed successively or simultaneously.
Since a temperature rise of 3-5 times of the time constant can reach a certain stable value in general, the value range of L is further 3-5 optionally. [] The rounding is expressed, and can be rounded up or rounded down according to actual needs. A sampling period represents the length of time corresponding to a sampling period, i.e. the time constant of the initial sampling period. Since the sampling period corresponding to the current time point is taken as the initial sampling period, the primary current corresponds to the primary current in the initial sampling period, for example, the average value of the primary currents in the initial sampling period. In practice, N can be determined to be a positive integer by setting s, for example, the time constant is 100 minutes, s can be 25 minutes, and thus N is 4. Assuming that L is 5, X is 20, which corresponds to 500 minutes, i.e. 8 hours or more.
In this embodiment, a first predicted temperature rise at the end of the next sampling period may be determined according to the fifth temperature rise and the sixth temperature rise, a second predicted temperature rise at the end of the next sampling period may be determined according to the sixth temperature rise and the first predicted temperature rise, a third predicted temperature rise at the end of the next sampling period may be determined again according to the first predicted temperature rise and the second predicted temperature rise, and the above steps are repeated until the first temperature rise of the contact point at the end of the xth sampling period is determined. Specifically, the temperature rising trend of the next sampling period can be determined according to the temperature rising trends of the fifth temperature rise and the sixth temperature rise. This first temperature rise can be regarded as the predicted stable temperature rise corresponding to the contact point.
Specifically, for example, the first temperature rise T of the contact point may be determined according to the following formula:
T＝(ΔKn-ΔKn-1*e-1/N)/(1-e-1/N)
wherein, Δ Kn-1For a fifth temperature rise, Δ KnIs the sixth temperature rise.
The present invention can repeatedly perform steps a to c. For example, the steps a to c are repeatedly executed every 1 minute, so that the temperature rise after the corresponding preset time period can be always predicted, and the real-time monitoring of the temperature rise of the contact point of the switch cabinet is realized. More specifically, in the sampling process, steps 101 to 103 are repeatedly performed from one sampling period, where n represents the nth sampling period, Δ KnFor the temperature rise, Δ K, corresponding to the nth sampling periodn-1For the temperature rise corresponding to the (n-1) th sampling period, any one (n-1) th sampling period can be regarded as the initial sampling period of the invention, and then the subsequent steps are executed to continuously preset the temperature rise of the contact point of the switch cabinet, and further monitor the temperature rise.
For each same-attribute contact point, the method of the embodiment can be adopted to obtain the predicted first temperature rise, and the predicted first temperature rise is determined as the stable temperature rise corresponding to the same-attribute contact point.
The invention has many other ways to determine the predicted temperature rise at the end of each sampling period, which are not described herein again.
According to the invention, the temperature after the preset time period is predicted by acquiring the temperature rises at the beginning and the end of a sampling period, so that the temperature rise after the preset time period can be quickly determined, for example, the value after the temperature rise is stable is taken as the first temperature rise, and further, subsequent operations are executed through the predicted temperature rise, for example, whether the operation that the contact point with the same attribute has a fault occurs in the previous embodiment or not.
Example four
The present embodiment provides an apparatus for fault detection of a switchgear for performing the apparatus for fault detection of a switchgear of the first embodiment.
Fig. 3 is a schematic structural diagram of the fault detection device for a switch cabinet according to the present embodiment. The apparatus comprises an acquisition unit 301, a first determination unit 302, a modification unit 303 and a second determination unit 304.
The acquiring unit 301 is configured to acquire respective first temperature rises of a group of same-attribute contact points on three phases of a switch cabinet, where each group of same-attribute contact points is three contact points corresponding to the same position in the switch cabinet; the first determining unit 302 is configured to determine a target temperature rise from the first temperature rises; the correcting unit 303 is configured to correct the target temperature rise to obtain a corrected second temperature rise; the second determining unit 304 is configured to determine whether there is a failure of the same-attribute contact point according to the second temperature rise.
Optionally, the first determining unit 302 is specifically configured to: the largest one of the first temperature rises is determined as the target temperature rise.
Optionally, the correcting unit 303 is specifically configured to:
selecting one larger first temperature rise from the rest two first temperature rises as a reference temperature rise;
obtaining the corrected second temperature rise delta K according to the following formulaCm：
Wherein, Δ KCTo represent the target temperature rise, ICPrimary current, I, of a contact point of the same attribute corresponding to a target temperature riseBRepresenting primary current of a contact point with the same attribute corresponding to the reference temperature rise;
optionally, the primary current is an average value of the primary current in the current sampling period.
Optionally, the second determining unit 304 is specifically configured to:
comparing the second temperature rise with the reference temperature rise, and determining that the smaller one of the second temperature rise and the reference temperature rise is the third temperature rise and the larger one is the fourth temperature rise;
and if the fourth temperature rise is greater than the sum of the third temperature rise and a first preset factor and the fourth temperature rise is greater than the product of the third temperature rise and a second preset factor, determining that the same-attribute contact point corresponding to the fourth temperature rise has a fault.
The working method of each unit of this embodiment is the same as that of the previous embodiment, and is not described herein again.
According to the embodiment, the temperature rise of each phase of a group of contact points with the same attribute is transversely compared to determine which phase of the contact point fails, and the temperature rise to be compared is corrected before comparison so that the judgment result is more accurate, and the comparison is quicker, more convenient and better in accuracy.
EXAMPLE five
The present embodiment provides supplementary explanation on the apparatus for fault detection of a switchgear according to the foregoing embodiment.
In the apparatus for detecting a fault of a switch cabinet of this embodiment, the obtaining unit 301 specifically includes a first obtaining subunit 3011, a second obtaining subunit 3012, and a predicting subunit 3013.
The first obtaining subunit 3011 is configured to obtain a fifth temperature rise at the beginning and a sixth temperature rise at the end of an initial sampling period of a contact point of a switch cabinet, where the contact point is a contact position of at least two components of the switch cabinet; the second obtaining subunit 3012 is configured to obtain a time constant of a first-order inertial system of a switch cabinet; a predicting subunit 3013 is configured to predict a first temperature rise of the contact point at the end of the xth sampling period according to the fifth temperature rise, the sixth temperature rise, and a time constant, where L is a positive integer and L ≧ 3, s is a sampling period, and N ═ s ═ time constant.
Optionally, the predictor sub-unit 3013 is specifically configured to:
determining a first temperature rise T of the contact point according to the following formula:
T＝(ΔKn-ΔKn-1*e-1/N)/(1-e-1/N)
wherein, Δ Kn-1For a fifth temperature rise, Δ KnIs the sixth temperature rise.
The working method of each unit of this embodiment is the same as that of the previous embodiment, and is not described herein again.
According to the invention, the temperature after the preset time period is predicted by acquiring the temperature rises at the beginning and the end of a sampling period, so that the temperature rise after the preset time period can be quickly determined, for example, the value after the temperature rise is stable is taken as the first temperature rise, and further, subsequent operations are executed through the predicted temperature rise, for example, whether the operation that the contact point with the same attribute has a fault occurs in the previous embodiment or not.
The invention also provides another device for fault detection of a switch cabinet. The apparatus includes at least one memory and at least one processor. Wherein the memory is to store instructions. The processor is configured to perform the method for fault detection of a switchgear as described in any of the preceding embodiments, according to instructions stored by the memory.
Embodiments of the present invention also provide a readable storage medium. The readable storage medium has stored therein machine readable instructions which, when executed by a machine, perform the method for fault detection of a switchgear as described in any of the preceding embodiments.
The readable medium has stored thereon machine readable instructions which, when executed by a processor, cause the processor to perform any of the methods previously described. In particular, a system or apparatus may be provided which is provided with a readable storage medium on which software program code implementing the functionality of any of the embodiments described above is stored and which causes a computer or processor of the system or apparatus to read and execute machine-readable instructions stored in the readable storage medium.
In this case, the program code itself read from the readable medium can realize the functions of any of the above-described embodiments, and thus the machine-readable code and the readable storage medium storing the machine-readable code form part of the present invention.
Examples of the readable storage medium include floppy disks, hard disks, magneto-optical disks, optical disks (e.g., CD-ROMs, CD-R, CD-RWs, DVD-ROMs, DVD-RAMs, DVD-RWs, DVD + RWs), magnetic tapes, nonvolatile memory cards, and ROMs. Alternatively, the program code may be downloaded from a server computer or from the cloud via a communications network.
It will be understood by those skilled in the art that various changes and modifications may be made in the above-disclosed embodiments without departing from the spirit of the invention. Accordingly, the scope of the invention should be determined from the following claims.
It should be noted that not all steps and units in the above flows and system structure diagrams are necessary, and some steps or units may be omitted according to actual needs. The execution order of the steps is not fixed and can be adjusted as required. The apparatus structures described in the above embodiments may be physical structures or logical structures, that is, some units may be implemented by the same physical entity, or some units may be implemented by a plurality of physical entities, or some units may be implemented by some components in a plurality of independent devices.
In the above embodiments, the hardware unit may be implemented mechanically or electrically. For example, a hardware unit or processor may comprise permanently dedicated circuitry or logic (such as a dedicated processor, FPGA or ASIC) to perform the corresponding operations. The hardware units or processors may also include programmable logic or circuitry (e.g., a general purpose processor or other programmable processor) that may be temporarily configured by software to perform the corresponding operations. The specific implementation (mechanical, or dedicated permanent, or temporarily set) may be determined based on cost and time considerations.
While the invention has been shown and described in detail in the drawings and in the preferred embodiments, it is not intended to limit the invention to the embodiments disclosed, and it will be apparent to those skilled in the art that various combinations of the code auditing means in the various embodiments described above may be used to obtain further embodiments of the invention, which are also within the scope of the invention.
Claims (12)
1. A method for fault detection of electrical equipment, comprising:
acquiring respective first temperature rises of a group of same-attribute contact points on three phases of power equipment, wherein each group of same-attribute contact points are three contact points corresponding to the same position in the power equipment;
determining a target temperature rise from each of said first temperature rises;
correcting the target temperature rise to obtain a corrected second temperature rise;
determining whether the contact point with the same attribute has a fault according to the second temperature rise;
determining a target temperature rise from each of the first temperature rises includes determining a largest one of the first temperature rises as the target temperature rise;
correcting the target temperature rise, and acquiring a corrected second temperature rise comprises:
selecting a larger one of the two remaining first temperature rises as a reference temperature rise;
obtaining the corrected second temperature rise delta K according to the following formulaCm：
Wherein, Δ KCTo represent the target temperature rise, ICPrimary current, I, of a contact point of the same attribute corresponding to the target temperature riseBAnd representing the primary current of the contact point with the same attribute corresponding to the reference temperature rise.
2. The method of claim 1, wherein the primary current is an average of primary currents in a current sampling period.
3. The method of claim 1, wherein determining whether the homonymous contact point is malfunctioning based on the second temperature rise comprises:
comparing the second temperature rise with the reference temperature rise, and determining that the smaller one of the second temperature rise and the reference temperature rise is a third temperature rise and the larger one is a fourth temperature rise;
and if the fourth temperature rise is greater than the sum of the third temperature rise and a first preset factor and the fourth temperature rise is greater than the product of the third temperature rise and a second preset factor, determining that the contact point with the same attribute corresponding to the fourth temperature rise has a fault.
4. The method of any one of claims 1-3, wherein obtaining respective first temperature increases for three phases of an electrical device corresponding to the attributed contact point comprises:
acquiring a fifth temperature rise of a contact point of an electric device at the beginning of an initial sampling period and a sixth temperature rise at the end of the initial sampling period, wherein the contact point is a contact position of at least two components of the electric device;
acquiring a time constant of a first-order inertia system of the power equipment;
predicting a first temperature rise of the contact point at the end of an Xth sampling period according to the fifth temperature rise, the sixth temperature rise and the time constant, wherein L is a positive integer and is more than or equal to 3, s is one sampling period, and N is the time constant.
5. The method of claim 4, wherein predicting the first temperature rise of the contact point at the end of the Xth sampling period based on the fifth temperature rise, the sixth temperature rise, and the time constant comprises:
determining a first temperature rise T of the contact point according to the following formula:
T＝(ΔKn-ΔKn-1*e-1/N)/(1-e-1/N)
wherein, Δ Kn-1Is the firstFive temperature rise, Δ KnThe sixth temperature rise.
6. An apparatus for fault detection of electrical equipment, comprising:
the system comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for acquiring respective first temperature rises of a group of same-attribute contact points on three phases of power equipment, and each group of same-attribute contact points are three contact points corresponding to the same position in the power equipment;
a first determining unit for determining a target temperature rise from among the first temperature rises;
the correcting unit is used for correcting the target temperature rise to obtain a corrected second temperature rise;
a second determining unit for determining whether there is a failure in the same-attribute contact point according to the second temperature rise;
wherein the first determining unit is specifically configured to: determining one of the first temperature rises with the largest value as a target temperature rise;
the correction unit is specifically configured to:
selecting a larger one of the two remaining first temperature rises as a reference temperature rise;
obtaining the corrected second temperature rise delta K according to the following formulaCm：
Wherein, Δ KCTo represent the target temperature rise, ICPrimary current, I, of a contact point of the same attribute corresponding to the target temperature riseBAnd representing the primary current of the contact point with the same attribute corresponding to the reference temperature rise.
7. The apparatus of claim 6,
the primary current is an average value of the primary current in the current sampling period.
8. The apparatus according to claim 6, wherein the second determining unit is specifically configured to:
comparing the second temperature rise with the reference temperature rise, and determining that the smaller one of the second temperature rise and the reference temperature rise is a third temperature rise and the larger one is a fourth temperature rise;
and if the fourth temperature rise is greater than the sum of the third temperature rise and a first preset factor and the fourth temperature rise is greater than the product of the third temperature rise and a second preset factor, determining that the contact point with the same attribute corresponding to the fourth temperature rise has a fault.
9. The apparatus according to any one of claims 6-8, wherein the obtaining unit specifically comprises:
a first obtaining subunit, configured to obtain a fifth temperature rise at a start time and a sixth temperature rise at an end time of a contact point of an electrical device at the start of an initial sampling period, where the contact point is a contact position of at least two components of the electrical device;
a second acquisition subunit, configured to acquire a time constant of a first-order inertial system of the electrical device;
and a prediction subunit, configured to predict, according to the fifth temperature rise, the sixth temperature rise, and the time constant, a first temperature rise of the contact point at the end of an xth sampling period, where L is a positive integer and L is greater than or equal to 3, s is one sampling period, and N is the time constant.
10. The apparatus of claim 9, wherein the predictor unit is specifically configured to:
determining a first temperature rise T of the contact point according to the following formula:
T＝(ΔKn-ΔKn-1*e-1/N)/(1-e-1/N)
wherein, Δ Kn-1For the fifth temperature rise, Δ KnThe sixth temperature rise.
11. An apparatus for fault detection of electrical equipment, comprising:
at least one memory for storing instructions;
at least one processor for performing the method for fault detection of a power device according to any one of claims 1-5 according to instructions stored by the memory.
12. Readable storage medium, in which machine readable instructions are stored, which when executed by a machine, the machine performs a method for fault detection of an electrical device according to any one of claims 1-5.
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