Method and system for identifying heavy load and overload of transformer

Abstract

The invention provides a transformer heavy overload identification method and system, and the method comprises the steps: obtaining a transformer in an operation state and related information of the transformer, including all meters corresponding to the transformer, the type and multiplying power of each meter, and the three-phase current, three-phase voltage and active power of a primary side and a secondary side; according to the obtained type, multiplying power, primary side and secondary side three-phase current, three-phase voltage and active power of each meter in each transformer, selecting a transformer meeting a preset condition combination; and determining primary side three-phase current of all meters corresponding to each selected transformer, calculating the maximum load rate of three phases in each selected transformer according to the preset rated capacity corresponding to each selected transformer, and further identifying the heavy overload condition of each selected transformer according to the maximum load rate of three phases in each selected transformer. By implementing the method, the problems of high cost investment and low identification accuracy in the existing identification method can be solved, and the identification accuracy of the heavy overload of the transformer is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a method and system for identifying severe overload of a transformer. Background Art

[0002] Transformers are important equipment in power systems, and their stability is directly related to the reliability and safety of the power grid. Due to the fact that future additional loads (such as a surge in new energy electric vehicles, new construction sites, etc.) were not fully considered in the early stage or the load was not reasonably distributed during the design and construction process, transformer failure or temporary load transfer during line maintenance caused the transformer to be overloaded in a short period of time. Once the transformer overload is not handled in time, not only will the power loss increase, efficiency decrease, and output voltage fluctuation increase, affecting the power quality, but it will also cause a series of problems such as equipment heating and accelerated aging of insulation materials, and even cause serious consequences such as power outages, explosions, and fires in surrounding facilities. Therefore, it is particularly important to design an effective and timely method to identify heavy overloads of transformers.

[0003] At present, the identification methods of transformer heavy overload include: (a) installing a set of online monitoring equipment on the transformer side to monitor the transformer's operating status, load current, oil temperature and other parameters, and regularly going to the site to analyze the dissolved gas in the oil. Although this method can promptly discover and deal with internal fault hazards, the cost investment is very large, it is difficult to cover all transformers, and it is difficult to connect with the existing system of the power supply department, and it is impossible to analyze and judge from multiple dimensions. (b) Using the metering device corresponding to the transformer to collect active power to analyze whether the maximum instantaneous active power of the transformer in a period of time exceeds the alarm threshold. Although this method is simple and can accurately identify heavily overloaded transformers to a certain extent, for heavy overloads with unbalanced three-phase loads, its active power may not exceed the set threshold and will not be judged as heavy overload, which may cause the transformer to fail or catch fire and burn. It has certain limitations.

[0004] Therefore, in order to solve the above problems, a new identification method for transformer heavy overload is urgently needed to improve the identification accuracy of transformer heavy overload. Summary of the invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide a method and system for identifying severe overload of a transformer, which can solve the problems of high cost investment and low recognition accuracy in existing recognition methods, and improve the recognition accuracy of severe overload of the transformer.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a method for identifying a transformer heavy overload, the method comprising the following steps:

[0007] Obtain a transformer whose operating status is running and related information thereof; wherein the related information includes all meters corresponding to the transformer, and the type, multiplier, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter;

[0008] According to the type, magnification, primary three-phase current, secondary three-phase current, primary three-phase voltage and primary active power of each meter in each transformer obtained, a transformer that meets a predetermined condition combination is selected from the obtained transformers; wherein the predetermined condition combination includes a first predetermined condition and a second predetermined condition; the first predetermined condition is determined by the primary three-phase current, primary three-phase voltage and primary active power of each meter in each transformer obtained; the second predetermined condition is determined by the type, magnification, primary three-phase current and secondary three-phase current of each meter in each transformer obtained;

[0009] The primary-side three-phase currents of all meters corresponding to each selected transformer are determined, and the maximum load rate of the three phases in each selected transformer is calculated in combination with the preset rated capacity corresponding to each selected transformer, and further the heavy overload condition of each selected transformer is identified based on the maximum load rate of the three phases in each selected transformer.

[0010] The steps of determining the primary three-phase currents of all meters corresponding to each selected transformer, and calculating the maximum load rate of the three phases in each selected transformer in combination with the preset rated capacity corresponding to each selected transformer, and further identifying the heavy overload condition of each selected transformer according to the maximum load rate of the three phases in each selected transformer specifically include:

[0011] Determine the primary three-phase currents of all meters corresponding to each selected transformer, and count the top three values ​​of the maximum primary A-phase current, the top three values ​​of the maximum primary B-phase current, and the top three values ​​of the maximum primary C-phase current of all meters in each selected transformer, and further calculate the maximum load current of the A-phase, the B-phase, and the C-phase corresponding to each selected transformer in combination with the preset A-phase weight value, the B-phase weight value, and the C-phase weight value;

[0012] The maximum load current of phase A, the maximum load current of phase B and the maximum load current of phase C of each selected transformer are calculated respectively with their corresponding rated capacities to obtain the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C of each selected transformer;

[0013] If it is determined that at least one of the maximum load rate of phase A, the maximum load rate of phase B, and the maximum load rate of phase C in the currently selected transformer is greater than or equal to a first preset value, then it is determined that the currently selected transformer is overloaded;

[0014] If it is determined that at least one of the maximum load rates of phase A, phase B and phase C in the currently selected transformer is less than the first preset value and greater than or equal to the second preset value, the currently selected transformer is determined to be overloaded.

[0015] Wherein, the method further comprises:

[0016] If it is determined that the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C in the currently selected transformer are all less than the second preset value, it is determined that the currently selected transformer is normal.

[0017] Among them, through the formula R i =(α i *I i1 +β i *I i2 +λ i *I i3 ) / (W*T), calculate the maximum load rate R of phase A, phase B and phase C in any selected transformer i ;in,

[0018] i=1, 2, 3 correspond to phase A, phase B and phase C respectively; α i , β i , i The three weight values ​​are assigned to the first three largest values ​​of the single-phase current in sequence, and they are all fixed values; I i1 ,I i2 ,I i3 The first three digits of the largest single-phase current on the primary side of all meters in the currently selected transformer, I i1 is the maximum, I i3 is the minimum; α i *I i1 +β i *I i2 +λ i *I i3 is the maximum load current of the single phase corresponding to the currently selected transformer; W is the rated capacity of the currently selected transformer; T is a constant.

[0019] The first predetermined condition is that the difference between the primary-side three-phase current of each meter in the same transformer and the three-phase current value calculated based on the primary-side three-phase voltage and the primary-side active power is within a predetermined error range; or

[0020] The number of times the instantaneous values ​​of the primary side three-phase current, the primary side three-phase voltage and the primary side active power of all meters in the same transformer appear is greater than or equal to the preset upper limit.

[0021] Among them, the second predetermined condition is that the primary side three-phase currents of all types and multipliers of meters in the transformer are greater than the first current threshold, the secondary side three-phase currents of meters of type three-phase three-wire and with a multiplier of 1 are less than the second current threshold, and the primary side three-phase currents of meters of type three-phase four-wire and with a multiplier of 1 are less than the third current threshold and the secondary side three-phase currents are less than the fourth current threshold.

[0022] The embodiment of the present invention further provides a transformer heavy overload identification system, comprising:

[0023] A transformer acquisition unit, used to acquire a transformer whose operating state is running and related information thereof; wherein the related information includes all meters corresponding to the transformer, and the type, multiplier, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter;

[0024] A transformer screening unit, for selecting a transformer that meets a predetermined condition combination from the obtained transformers according to the type, magnification, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter in each transformer obtained; wherein the predetermined condition combination includes a first predetermined condition and a second predetermined condition; the first predetermined condition is determined by the primary side three-phase current, primary side three-phase voltage and primary side active power of each meter in each transformer obtained; the second predetermined condition is determined by the type, magnification, primary side three-phase current and secondary side three-phase current of each meter in each transformer obtained;

[0025] The transformer heavy overload identification unit is used to determine the primary side three-phase currents of all meters corresponding to each selected transformer, and calculate the maximum load rate of the three phases in each selected transformer in combination with the preset rated capacity corresponding to each selected transformer, and further identify the heavy overload situation of each selected transformer based on the maximum load rate of the three phases in each selected transformer.

[0026] Wherein, the transformer heavy overload identification unit comprises:

[0027] The three-phase maximum load current calculation module is used to determine the primary three-phase currents of all meters corresponding to each selected transformer, and to count the top three values ​​of the maximum primary A-phase current, the top three values ​​of the maximum primary B-phase current, and the top three values ​​of the maximum primary C-phase current of all meters in each selected transformer, and further calculate the maximum load current of the A-phase, the B-phase, and the C-phase corresponding to each selected transformer in combination with the preset A-phase weight value, the B-phase weight value, and the C-phase weight value;

[0028] The three-phase maximum load rate calculation module is used to calculate the maximum load current of phase A, phase B and phase C of each selected transformer respectively with their corresponding rated capacity to obtain the maximum load rate of phase A, phase B and phase C of each selected transformer;

[0029] A transformer overload identification module, configured to determine that the currently selected transformer is overloaded if it is determined that at least one of the maximum load rate of phase A, the maximum load rate of phase B, and the maximum load rate of phase C in the currently selected transformer is greater than or equal to a first preset value;

[0030] The transformer overload identification module is used to determine that the currently selected transformer is overloaded if at least one of the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C in the currently selected transformer is less than the first preset value and greater than or equal to the second preset value.

[0031] Wherein, the transformer heavy overload identification unit also includes:

[0032] The transformer normal identification module is used to determine that the currently selected transformer is normal if it is determined that the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C in the currently selected transformer are all less than the second preset value.

[0033] Among them, through the formula R i =(α i *I i1 +β i *I i2 +λ i *I i3 ) / (W*T), calculate the maximum load rate R of phase A, phase B and phase C in any selected transformer i ;in,

[0034] i=1, 2, 3 correspond to phase A, phase B and phase C respectively; α i , β i , i The three weight values ​​are assigned to the first three largest values ​​of the single-phase current in sequence, and they are all fixed values; I i1 ,I i2 ,I i3 The first three digits of the largest single-phase current on the primary side of all meters in the currently selected transformer, I i1 is the maximum, I i3 is the minimum; α i *I i1 +β i *I i2 +λ i *I i3is the maximum load current of the single phase corresponding to the currently selected transformer; W is the rated capacity of the currently selected transformer; T is a constant.

[0035] Implementing the embodiments of the present invention has the following beneficial effects:

[0036] The present invention performs a combination screening of predetermined conditions on the running transformer based on the type, multiple, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of the transformer corresponding meter, and calculates the maximum load rate of the three phases in the transformer in combination with the rated capacity of the transformer, so as to quickly identify the heavy overload condition of the transformer, thereby solving the problems of high cost investment and low recognition accuracy in the existing recognition method and improving the recognition accuracy of the heavy overload of the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0038] Figure 1 A flowchart of a method for identifying a severe overload of a transformer provided by an embodiment of the present invention;

[0039] Figure 2 A schematic diagram of the structure of a transformer severe overload identification system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0041] like Figure 1 As shown in the figure, a method for identifying a transformer heavy overload is proposed in an embodiment of the present invention, and the method comprises the following steps:

[0042] Step S1, obtaining a transformer whose operating state is running and related information thereof; wherein the related information includes all meters corresponding to the transformer, and the type, multiplier, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter;

[0043] Step S2, according to the type, magnification, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter in each transformer obtained, select a transformer that meets the predetermined condition combination from the obtained transformers; wherein the predetermined condition combination includes a first predetermined condition and a second predetermined condition; the first predetermined condition is determined by the primary side three-phase current, primary side three-phase voltage and primary side active power of each meter in each transformer obtained; the second predetermined condition is determined by the type, magnification, primary side three-phase current and secondary side three-phase current of each meter in each transformer obtained;

[0044] Step S3, determine the primary three-phase currents of all meters corresponding to each selected transformer, and calculate the maximum load rate of the three phases in each selected transformer in combination with the preset rated capacity corresponding to each selected transformer, and further identify the heavy overload condition of each selected transformer based on the maximum load rate of the three phases in each selected transformer.

[0045] The specific process is as follows: in step S1, a transformer whose operating status is running and related information are obtained, and the related information includes but is not limited to all meters corresponding to the transformer, and the type, multiple, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter.

[0046] It can be understood that a meter with a multiplier of 1 is called a through meter, and a meter with a multiplier greater than 1 is called a multiplier meter.

[0047] It should be noted that the transformer and its related information are all from the marketing system. Therefore, from the marketing system, extract the "operating status" of the transformer, the "bureau code, user number, type, ratio, primary current, secondary current, primary voltage, secondary voltage, primary active power and secondary active power" of the corresponding meter of the transformer; among them, the bureau code and user number are used to determine the meter corresponding to the user. At this time, the operating status of the transformer is "operating". If it is in other operating states, it will not be included in the subsequent transformer overload identification. In addition, the single-phase meter is not included in the transformer overload identification because it cannot accurately reflect the three-phase imbalance phenomenon.

[0048] In step S2, considering that using the load current at a certain point in time as an identification condition for determining whether the transformer is severely overloaded is rather one-sided and often results in false alarms or misreporting, the present invention sets a condition combination to screen out transformers with current uncertainty, thereby improving detection accuracy.

[0049] At this time, first, a condition combination is set to include a first predetermined condition and a second predetermined condition; wherein the first predetermined condition is that the difference between the primary-side three-phase current of each meter in the same transformer and the three-phase current value calculated based on the primary-side three-phase voltage and the primary-side active power is within a predetermined error range; or the number of occurrences of the instantaneous value of the primary-side three-phase current, the instantaneous value of the primary-side three-phase voltage and the instantaneous value of the primary-side active power of all meters in the same transformer is greater than or equal to a preset upper limit (such as 10 times).

[0050] In one example, the corresponding three-phase current can be reversely calculated through the commonly used active power formula in this field, and an error range can be set. If the difference between the primary three-phase current displayed by the meter and the calculated three-phase current value falls within the error range, it is determined that the first predetermined condition is met; otherwise, it is determined that the first predetermined condition is not met.

[0051] The second predetermined condition is that the three-phase currents on the primary side of all types and ratios of meters in the transformer are greater than the first current threshold (such as 0A, that is, the meter measurement value is not empty), the three-phase currents on the secondary side of meters of type three-phase three-wire and with a ratio of 1 are less than the second current threshold (such as 11A), and the three-phase currents on the primary side of meters of type three-phase four-wire and with a ratio of 1 are less than the third current threshold (such as 200A) and the three-phase currents on the secondary side are less than the fourth current threshold (such as 8A).

[0052] In one example, for a three-phase four-wire meter with a magnification of 1, if the primary current of any phase of the three-phase currents ABC is greater than the third current threshold of 200A, it is determined that the second predetermined condition is not met; for another example, if the maximum primary or secondary three-phase current of a three-phase four-wire or three-phase three-wire meter with a magnification of 1 is 0, that is, less than or equal to the first current threshold of 0A, it is determined that the second predetermined condition is not met; for another example, for a three-phase four-wire meter with a magnification greater than 1, if the secondary current of any phase of the three-phase currents ABC is greater than the fourth current threshold of 8A, it is determined that the second predetermined condition is not met; for another example, for a three-phase three-wire meter with a magnification greater than 1, if the secondary current of any phase of the three-phase currents ABC is greater than the second current threshold of 11A, it is determined that the second predetermined condition is not met. It should be noted that the first to fourth current thresholds can be flexibly adjusted according to actual conditions.

[0053] In step S3, first, the primary three-phase currents of all meters corresponding to each selected transformer are determined, and the top three values ​​of the maximum primary A-phase current, the top three values ​​of the maximum primary B-phase current, and the top three values ​​of the maximum primary C-phase current of all meters in each selected transformer are counted, and further combined with the preset A-phase weight value, B-phase weight value, and C-phase weight value, the maximum load current of A-phase, the maximum load current of B-phase, and the maximum load current of C-phase corresponding to each selected transformer are calculated.

[0054] In one example, by formula I maxi =α i *I i1 +β i *I i2 +λ i *I i3 , calculate the maximum load current I corresponding to the single phase of the currently selected transformer maxi Among them, i = 1, 2, 3 correspond to phase A, phase B and phase C respectively, that is, I max1 is the maximum load current of phase A on the primary side, I max2 is the maximum load current of phase B on the primary side, I max3 is the maximum load current of phase C on the primary side; I i1 ,I i2 ,I i3 The first three digits of the largest single-phase current on the primary side of all meters in the currently selected transformer, I i1 is the maximum, I i2 Next, I i3 is the minimum; α i , β i , i The three weight values ​​​​given to the first three largest values ​​of the primary side single-phase current are fixed values, that is, α 1 , β 1 , 1 are the three weight values ​​of phase A, α 2 , β 2 , 2 are the three weight values ​​of phase B, α 3 , β 3 , 3 are the three weight values ​​of phase C.

[0055] Secondly, the maximum load current of phase A, the maximum load current of phase B and the maximum load current of phase C of each selected transformer are calculated respectively with their corresponding rated capacities to obtain the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C of each selected transformer.

[0056] In one example, by formula R i =I maxi / (W*T)=(α i *I i1 +β i *I i2 +λ i *I i3 ) / (W*T), calculate the maximum load rate R of phase A, phase B and phase C in any selected transformer i , that is, R 1 is the maximum load factor of phase A, R 2is the maximum load rate of phase B, R 3 is the maximum load rate of phase C; W is the rated capacity of the currently selected transformer; T is a constant = 1.5.

[0057] Finally, if it is determined that at least one of the maximum load rates of phase A, phase B, and phase C in the currently selected transformer is greater than or equal to the first preset value (such as 1), it is determined that the currently selected transformer is overloaded; or

[0058] if it is determined that at least one of the maximum load rates of phase A, phase B, and phase C in the currently selected transformer is less than the first preset value and greater than or equal to the second preset value (such as 0.8), it is determined that the currently selected transformer is heavily loaded.

[0059] It can be understood that the normality of the currently selected transformer can also be determined based on other comparison results of the maximum load rates of phase A, phase B, and phase C. Therefore, if it is determined that the maximum load rates of phase A, phase B, and phase C in the currently selected transformer are all less than the second preset value, it is determined that the currently selected transformer is normal.

[0060] In one example, if the maximum load rate R of phase A 1 >= the first preset value 1, or the maximum load rate R of phase B 2 >= the first preset value 1, or the maximum load rate R of phase C 3 >= the first preset value 1, then it is determined that the currently selected transformer is heavily loaded;

[0061] if the second preset value 0.8 = < the maximum load rate R of phase A 1 < the first preset value 1, or the second preset value 0.8 = < the maximum load rate R of phase B 2 < the first preset value 1, or the second preset value 0.8 = < the maximum load rate R of phase C 3 < the first preset value 1, then it is determined that the currently selected transformer is overloaded;

[0062] if the maximum load rate R of phase A 1 < the second preset value 0.8, the maximum load rate R of phase B 2 < the second preset value 0.8 and the maximum load rate R of phase C 3 < the second preset value 0.8, then it is determined that the currently selected transformer is normal.

[0063] The application scenario of a method for identifying heavy overload of a transformer provided in an embodiment of the present invention is further described as follows:

[0064] 1. In the marketing system, extract the "operating status" of the transformer, the "bureau code, user number, type, ratio, and current, voltage and active power on the primary and secondary sides" of the transformer's corresponding meter and other information; among them, the bureau code and user number are used to determine the meter corresponding to the user.

[0065] 2. Determine whether the operating status of the transformer is "operating". If it is in other operating status, it will not be included in the subsequent transformer heavy overload identification.

[0066] 3. Determine whether the number of times the transformer corresponding meter obtains the instantaneous value of the primary side three-phase current, the primary side three-phase voltage and the primary side active power on the verification day is greater than or equal to 10; if not, it will not be included in the subsequent transformer heavy overload identification.

[0067] It should be noted that the primary side three-phase voltage and primary side active power can be used to determine whether the primary side current is normal. For example, the corresponding three-phase current is calculated based on the primary side three-phase voltage and primary side active power, and the calculated three-phase current is compared with the measured primary side current to determine whether the current is true. If it is not true, it will not be included in the subsequent transformer heavy overload identification.

[0068] 4. Determine whether the three-phase current of the transformer corresponding meter has one of the following conditions:

[0069] 1. For a three-phase four-wire meter with a magnification of 1, the primary current of any phase among the three-phase currents ABC is greater than the third current threshold of 200A;

[0070] 2. For a three-phase four-wire or three-phase three-wire meter with a multiplier greater than 1, the secondary current of any phase among the three-phase currents ABC is greater than the set value (such as greater than the second current threshold 11A, greater than the fourth current threshold 8A).

[0071] 3. The maximum value of the primary or secondary current on this verification day is the first current threshold value 0.

[0072] 5. Determine the maximum load rate of the transformer, including: (1) Maximum load rate of each phase = maximum load current / (rated capacity of transformer*1.5) (2) Maximum load rate of the transformer: take the maximum load rate of each of the three phases ABC.

[0073] 4. Determine whether the maximum load rates of the three phases ABC of the transformer are all less than 0.8. If so, determine that the transformer load is normal; if not, determine whether the maximum load rate of one of the three phases ABC is greater than or equal to 1. If so, determine that the transformer is overloaded; if not, that is, the maximum load rate of one of the three phases ABC is greater than or equal to 0.8 and less than 1, then determine that the transformer is overloaded.

[0074] like Figure 2As shown in the figure, a transformer heavy overload identification system is provided in an embodiment of the present invention, comprising:

[0075] The transformer acquisition unit 110 is used to acquire a transformer whose operating state is running and related information thereof; wherein the related information includes all meters corresponding to the transformer, and the type, multiplier, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter;

[0076] The transformer screening unit 120 is used to select a transformer that meets a predetermined condition combination from the obtained transformers according to the type, magnification, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter in each transformer obtained; wherein the predetermined condition combination includes a first predetermined condition and a second predetermined condition; the first predetermined condition is determined by the primary side three-phase current, primary side three-phase voltage and primary side active power of each meter in each transformer obtained; the second predetermined condition is determined by the type, magnification, primary side three-phase current and secondary side three-phase current of each meter in each transformer obtained;

[0077] The transformer heavy overload identification unit 130 is used to determine the primary side three-phase currents of all meters corresponding to each selected transformer, and calculate the maximum load rate of the three phases in each selected transformer in combination with the preset rated capacity corresponding to each selected transformer, and further identify the heavy overload situation of each selected transformer based on the maximum load rate of the three phases in each selected transformer.

[0078] Wherein, the transformer heavy overload identification unit 130 includes:

[0079] The three-phase maximum load current calculation module is used to determine the primary three-phase currents of all meters corresponding to each selected transformer, and to count the top three values ​​of the maximum primary A-phase current, the top three values ​​of the maximum primary B-phase current, and the top three values ​​of the maximum primary C-phase current of all meters in each selected transformer, and further calculate the maximum load current of the A-phase, the B-phase, and the C-phase corresponding to each selected transformer in combination with the preset A-phase weight value, the B-phase weight value, and the C-phase weight value;

[0080] The three-phase maximum load rate calculation module is used to calculate the maximum load current of phase A, phase B and phase C of each selected transformer respectively with their corresponding rated capacity to obtain the maximum load rate of phase A, phase B and phase C of each selected transformer;

[0081] A transformer overload identification module, configured to determine that the currently selected transformer is overloaded if it is determined that at least one of the maximum load rate of phase A, the maximum load rate of phase B, and the maximum load rate of phase C in the currently selected transformer is greater than or equal to a first preset value;

[0082] The transformer overload identification module is used to determine that the currently selected transformer is overloaded if at least one of the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C in the currently selected transformer is less than the first preset value and greater than or equal to the second preset value.

[0083] The transformer heavy overload identification unit 130 further includes:

[0084] The transformer normal identification module is used to determine that the currently selected transformer is normal if it is determined that the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C in the currently selected transformer are all less than the second preset value.

[0085] Among them, through the formula R i =(α i *I i1 +β i *I i2 +λ i *I i3 ) / (W*T), calculate the maximum load rate R of phase A, phase B and phase C in any selected transformer i ;in,

[0086] i=1, 2, 3 correspond to phase A, phase B and phase C respectively; α i , β i , i The three weight values ​​are assigned to the first three largest values ​​of the single-phase current in sequence, and they are all fixed values; I i1 ,I i2 ,I i3 The first three digits of the largest single-phase current on the primary side of all meters in the currently selected transformer, I i1 is the maximum, I i3 is the minimum; α i *I i1 +β i *I i2 +λ i *I i3 is the maximum load current of the single phase corresponding to the currently selected transformer; W is the rated capacity of the currently selected transformer; T is a constant.

[0087] Implementing the embodiments of the present invention has the following beneficial effects:

[0088] The present invention performs a combination screening of predetermined conditions on the running transformer based on the type, multiple, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of the transformer corresponding meter, and calculates the maximum load rate of the three phases in the transformer in combination with the rated capacity of the transformer, so as to quickly identify the heavy overload condition of the transformer, thereby solving the problems of high cost investment and low recognition accuracy in the existing recognition method and improving the recognition accuracy of the heavy overload of the transformer.

[0089] It is worth noting that in the above system embodiment, the various system modules included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of the various functional modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention.

[0090] A person skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM / RAM, disk, CD-ROM, etc.

[0091] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for identifying severe overload of a transformer, characterized in that: The method comprises the following steps: Obtain a transformer whose operating status is running and related information thereof; wherein the related information includes all meters corresponding to the transformer, and the type, multiplier, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter; According to the type, magnification, primary three-phase current, secondary three-phase current, primary three-phase voltage and primary active power of each meter in each transformer obtained, a transformer that meets a predetermined condition combination is selected from the obtained transformers; wherein the predetermined condition combination includes a first predetermined condition and a second predetermined condition; the first predetermined condition is determined by the primary three-phase current, primary three-phase voltage and primary active power of each meter in each transformer obtained; the second predetermined condition is determined by the type, magnification, primary three-phase current and secondary three-phase current of each meter in each transformer obtained; The primary-side three-phase currents of all meters corresponding to each selected transformer are determined, and the maximum load rate of the three phases in each selected transformer is calculated in combination with the preset rated capacity corresponding to each selected transformer, and further the heavy overload condition of each selected transformer is identified based on the maximum load rate of the three phases in each selected transformer.

2. The method for identifying a transformer heavy overload according to claim 1, characterized in that: The steps of determining the primary-side three-phase currents of all meters corresponding to each selected transformer, and calculating the maximum load rate of the three phases in each selected transformer in combination with the preset rated capacity corresponding to each selected transformer, and further identifying the heavy overload condition of each selected transformer according to the maximum load rate of the three phases in each selected transformer specifically include: Determine the primary three-phase currents of all meters corresponding to each selected transformer, and count the top three values ​​of the maximum primary A-phase current, the top three values ​​of the maximum primary B-phase current, and the top three values ​​of the maximum primary C-phase current of all meters in each selected transformer, and further calculate the maximum load current of the A-phase, the B-phase, and the C-phase corresponding to each selected transformer in combination with the preset A-phase weight value, the B-phase weight value, and the C-phase weight value; The maximum load current of phase A, the maximum load current of phase B and the maximum load current of phase C of each selected transformer are calculated respectively with their corresponding rated capacities to obtain the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C of each selected transformer; If it is determined that at least one of the maximum load rate of phase A, the maximum load rate of phase B, and the maximum load rate of phase C in the currently selected transformer is greater than or equal to a first preset value, then it is determined that the currently selected transformer is overloaded; If it is determined that at least one of the maximum load rates of phase A, phase B and phase C in the currently selected transformer is less than the first preset value and greater than or equal to the second preset value, the currently selected transformer is determined to be overloaded.

3. The method for identifying a transformer heavy overload as claimed in claim 2, characterized in that: The method further comprises: If it is determined that the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C in the currently selected transformer are all less than the second preset value, it is determined that the currently selected transformer is normal.

4. The method for identifying a transformer heavy overload as claimed in claim 3, characterized in that: By formula R i =(α i *I i1 +β i *I i2 +λ i *I i3 ) / (W*T), calculate the maximum load rate R of phase A, phase B and phase C in any selected transformer i ;in, i=1, 2, 3 correspond to phase A, phase B and phase C respectively; α i , β i , i The three weight values ​​are assigned to the first three largest values ​​of the single-phase current in sequence, and they are all fixed values; I i1 ,I i2 ,I i3 The first three digits of the largest single-phase current on the primary side of all meters in the currently selected transformer, I i1 is the maximum, I i3 is the minimum; α i *I i1 +β i *I i2 +λ i *I i3 is the maximum load current of the single phase corresponding to the currently selected transformer; W is the rated capacity of the currently selected transformer; T is a constant.

5. The method for identifying a transformer heavy overload as claimed in claim 4, characterized in that: The first predetermined condition is that the difference between the primary side three-phase current of each meter in the same transformer and the three-phase current value calculated based on the primary side three-phase voltage and the primary side active power is within a predetermined error range; or The number of times the instantaneous values ​​of the primary side three-phase current, the primary side three-phase voltage and the primary side active power of all meters in the same transformer appear is greater than or equal to the preset upper limit.

6. The method for identifying a transformer severe overload as claimed in claim 4, characterized in that: The second predetermined condition is that the three-phase currents on the primary side of all types and ratios of meters in the transformer are greater than the first current threshold, the three-phase currents on the secondary side of meters of the type three-phase three-wire and the ratio of 1 are less than the second current threshold, and the three-phase currents on the primary side of meters of the type three-phase four-wire and the ratio of 1 are less than the third current threshold and the three-phase currents on the secondary side are less than the fourth current threshold.

7. A transformer overload identification system, characterized in that: include: A transformer acquisition unit, used to acquire a transformer whose operating state is running and related information thereof; wherein the related information includes all meters corresponding to the transformer, and the type, multiplier, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter; A transformer screening unit, for selecting a transformer that meets a predetermined condition combination from the obtained transformers according to the type, magnification, primary side three-phase current, secondary side three-phase current, primary side three-phase voltage and primary side active power of each meter in each transformer obtained; wherein the predetermined condition combination includes a first predetermined condition and a second predetermined condition; the first predetermined condition is determined by the primary side three-phase current, primary side three-phase voltage and primary side active power of each meter in each transformer obtained; the second predetermined condition is determined by the type, magnification, primary side three-phase current and secondary side three-phase current of each meter in each transformer obtained; The transformer heavy overload identification unit is used to determine the primary side three-phase currents of all meters corresponding to each selected transformer, and calculate the maximum load rate of the three phases in each selected transformer in combination with the preset rated capacity corresponding to each selected transformer, and further identify the heavy overload situation of each selected transformer based on the maximum load rate of the three phases in each selected transformer.

8. The transformer heavy overload identification system according to claim 7, characterized in that: The transformer heavy overload identification unit comprises: The three-phase maximum load current calculation module is used to determine the primary three-phase currents of all meters corresponding to each selected transformer, and to count the top three values ​​of the maximum primary A-phase current, the top three values ​​of the maximum primary B-phase current, and the top three values ​​of the maximum primary C-phase current of all meters in each selected transformer, and further calculate the maximum load current of the A-phase, the B-phase, and the C-phase corresponding to each selected transformer in combination with the preset A-phase weight value, the B-phase weight value, and the C-phase weight value; The three-phase maximum load rate calculation module is used to calculate the maximum load current of phase A, phase B and phase C of each selected transformer respectively with their corresponding rated capacity to obtain the maximum load rate of phase A, phase B and phase C of each selected transformer; A transformer overload identification module, configured to determine that the currently selected transformer is overloaded if it is determined that at least one of the maximum load rate of phase A, the maximum load rate of phase B, and the maximum load rate of phase C in the currently selected transformer is greater than or equal to a first preset value; The transformer overload identification module is used to determine that the currently selected transformer is overloaded if at least one of the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C in the currently selected transformer is less than the first preset value and greater than or equal to the second preset value.

9. The transformer heavy overload identification system according to claim 8, characterized in that: The transformer heavy overload identification unit also includes: The transformer normal identification module is used to determine that the currently selected transformer is normal if it is determined that the maximum load rate of phase A, the maximum load rate of phase B and the maximum load rate of phase C in the currently selected transformer are all less than the second preset value.

10. The transformer heavy overload identification system according to claim 9, characterized in that: By formula R i =(α i *I i1 +β i *I i2 +λ i *I i3 ) / (W*T), calculate the maximum load rate R of phase A, phase B and phase C in any selected transformer i ;in, i=1, 2, 3 correspond to phase A, phase B and phase C respectively; α i , β i , i The three weight values ​​are assigned to the first three largest values ​​of the single-phase current in sequence, and they are all fixed values; I i1 ,I i2 ,I i3 The first three digits of the largest single-phase current on the primary side of all meters in the currently selected transformer, I i1 is the maximum, I i3 is the minimum; α i *I i1 +β i *I i2 +λ i *I i3 is the maximum load current of the single phase corresponding to the currently selected transformer; W is the rated capacity of the currently selected transformer; T is a constant.

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