Distribution transformer rated capacity synchronization vector online detection method, device and equipment

Abstract

The embodiment of the invention discloses a distribution transformer rated capacity synchronous vector online detection method, device and equipment, and the method comprises the steps: synchronously collecting the synchronous vector operation data of a high-voltage side and a low-voltage side of a distribution transformer, decomposing to obtain first positive-sequence synchronous vector operation data of a high-voltage side and second positive-sequence synchronous vector operation data of a low-voltage side; performing excitation current calculation according to the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data to obtain positive-sequence excitation current; and calculating the rated capacity of the distribution transformer according to the positive sequence excitation current and the first positive sequence synchronous vector operation data. On-line detection of the rated capacity of the distribution transformer can be realized by carrying out capacity monitoring based on the synchronous vector operation data under the operation state of the distribution transformer, tedious power failure and test processes are omitted, the false capacity marked by a name plate of the distribution transformer can be quickly checked, correct verification of the electricity price is ensured, and the operation state of the distribution transformer can be monitored.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer parameter testing, and particularly to an on-line detection method, device and equipment for the rated capacity of a distribution transformer. Background Art

[0002] The capacity of a transformer is the basis for calculating electricity charges. The non-conformity between the rated capacity and the actual rated capacity of a distribution transformer will not only directly affect the economic benefits of the power supply department, but also may cause light-load and over-load operation of the transformer, thus affecting the safe and reliable operation of the distribution network. At present, the main methods for detecting the capacity of a transformer are the loss comparison method, the impedance voltage method, etc., all of which are off-line measurements. In on-site testing, a short-circuit test is usually used to confirm the capacity of the transformer. From the definition of the short-circuit impedance of the transformer, it can be known that: the short-circuit impedance is equal to the ratio of the primary-side voltage to the rated voltage when the primary side of the transformer is applied with voltage and the short-circuit current on the secondary side reaches the rated current.

[0003] In the technical solution of a transformer capacity testing method in the existing patent CN103063963A, the capacity of the transformer is measured and calculated by performing an open-circuit test and a load test on the transformer. When the transformer is subjected to an open-circuit test, it needs to be shut down, making the transformer itself in a power-off state. Detecting the capacity of the transformer while power-off not only wastes a large amount of manpower and material resources, but also does not meet the requirements of the power grid for economic and uninterrupted power supply. Secondly, if the actual capacity of the transformer is determined by the short-circuit impedance of the transformer, the accurate short-circuit impedance of the transformer to be measured needs to be known in advance. The short-circuit impedance is generally marked on the nameplate of the transformer. For such transformers, since the accurate short-circuit impedance information cannot be obtained, the conventional capacity testing method cannot be used.

[0004] Based on this, the current methods for measuring the rated capacity of a transformer have the following problems: First, when performing on-site testing, the transformer needs to be shut down, which will seriously affect the power supply quality and the economic operation of the distribution network; second, distribution transformers are characterized by a large number and wide distribution. Using the method of manual on-site verification not only requires a large amount of manpower and material resources, but also has extremely low verification efficiency, and it is difficult to conduct a one-by-one investigation of the rated capacity of all transformers. Summary of the Invention

[0005] Based on this, it is necessary to propose an on-line synchronous vector detection method, device and equipment for the rated capacity of a distribution transformer to achieve on-line detection of the rated capacity of the distribution transformer.

[0006] To achieve the above object, in the first aspect of the present application, an on-line synchronous vector detection method for the rated capacity of a distribution transformer is provided. The method includes:

[0007] Synchronously collecting the synchronous vector operation data of the high-voltage side and the low-voltage side of the distribution transformer;

[0008] Based on the symmetrical component method, the synchronous vector operation data on the high-voltage side and the low-voltage side are respectively decomposed to obtain the first positive-sequence synchronous vector operation data on the high-voltage side and the second positive-sequence synchronous vector operation data on the low-voltage side;

[0009] According to the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data, the exciting current is calculated to obtain the positive-sequence exciting current;

[0010] According to the positive-sequence exciting current and the first positive-sequence synchronous vector operation data, the rated capacity of the distribution transformer is calculated.

[0011] Further, the positive-sequence synchronous vector operation data at least includes positive-sequence current;

[0012] Then, the calculating the positive-sequence exciting current according to the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data specifically includes:

[0013] The second positive-sequence current on the low-voltage side of the distribution transformer is reduced to the high-voltage side of the distribution transformer to obtain a third positive-sequence current reduced to the high-voltage side;

[0014] Based on the positive-sequence equivalent circuit of the distribution transformer, a formula for calculating the positive-sequence exciting current is determined;

[0015] The third positive-sequence current and the first positive-sequence current on the high-voltage side of the distribution transformer are substituted into the formula for calculating the positive-sequence exciting current for calculation to obtain the positive-sequence exciting current.

[0016] Further, the reducing the second positive-sequence current on the low-voltage side of the distribution transformer to the high-voltage side of the distribution transformer to obtain a third positive-sequence current reduced to the high-voltage side specifically includes:

[0017] Obtain the rated voltage ratio and connection group of the distribution transformer at the current operating tap;

[0018] Based on the connection group of the distribution transformer, a rotation factor is determined;

[0019] According to the rotation factor, the second positive-sequence current, and the rated voltage ratio, equivalent calculation is performed to obtain the third positive-sequence current obtained by reducing the second positive-sequence current to the high-voltage side.

[0020] Further, the third positive-sequence current is calculated according to the following formula:

[0021]

[0022] Wherein, is the third positive-sequence current, is the second positive sequence current on the low-voltage side of the distribution transformer, is the rotation factor, where j is the imaginary unit, is the angle by which the high-voltage winding in the distribution transformer leads the low-voltage winding, and k is the rated voltage ratio of the distribution transformer at the current operating tap position.

[0023] Further, the positive sequence exciting current is calculated by the following formula:

[0024]

[0025] In the formula, is the positive sequence exciting current, is the first positive sequence current, is the third positive sequence current.

[0026] Further, the positive sequence synchronous vector operation data further includes the positive sequence voltage;

[0027] Then calculating the rated capacity of the distribution transformer based on the positive sequence exciting current and the first positive sequence synchronous vector operation data specifically includes:

[0028] Obtain the no-load current percentage of the distribution transformer and the rated voltage of the high-voltage side;

[0029] Perform capacity calculation according to the no-load current percentage, the rated voltage, the first positive sequence voltage on the high-voltage side of the distribution transformer, and the positive sequence exciting current to obtain the rated capacity of the distribution transformer.

[0030] Further, the rated capacity of the distribution transformer is calculated by the following formula:

[0031]

[0032] In the formula, S N is the rated capacity of the distribution transformer, imag() is the imaginary part extraction function, is the positive sequence exciting current, is the first positive sequence voltage on the high-voltage side of the distribution transformer, U N is the rated voltage of the high-voltage side of the distribution transformer, and I0% is the no-load current percentage of the distribution transformer.

[0033] To achieve the above object, a second aspect of the present application provides an on-line detection device for the rated capacity of a distribution transformer by synchronous vector. The on-line detection device includes a parameter measurement module, a parameter processing module, and a capacity calculation module;

[0034] The parameter measurement module is used to synchronously collect the synchronous vector operation data of the high-voltage side and the low-voltage side of the distribution transformer;

[0035] The parameter processing module is configured to decompose the synchronous vector operation data of the high-voltage side and the low-voltage side respectively based on the symmetrical component method, so as to obtain the first positive-sequence synchronous vector operation data of the high-voltage side and the second positive-sequence synchronous vector operation data of the low-voltage side;

[0036] The capacity calculation module is configured to calculate the excitation current according to the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data, so as to obtain the positive-sequence excitation current;

[0037] The rated capacity of the distribution transformer is calculated according to the positive-sequence excitation current and the first positive-sequence synchronous vector operation data.

[0038] To achieve the above object, a third aspect of the present application provides a computer-readable storage medium storing a computer program, which when executed by a processor causes the processor to execute the steps of the method as described in the first aspect.

[0039] To achieve the above object, a fourth aspect of the present application provides a computer device including a memory and a processor, where the memory stores a computer program, and when the computer program is executed by the processor, it causes the processor to execute the steps of the method as described in the first aspect.

[0040] Adopting the embodiments of the present invention has the following beneficial effects:

[0041] The embodiments of the present invention propose a method for online detection of the rated capacity of a distribution transformer by synchronous vector. The method includes: synchronously collecting the synchronous vector operation data of the high-voltage side and the low-voltage side of the distribution transformer; decomposing the synchronous vector operation data of the high-voltage side and the low-voltage side respectively based on the symmetrical component method to obtain the first positive-sequence synchronous vector operation data of the high-voltage side and the second positive-sequence synchronous vector operation data of the low-voltage side; calculating the excitation current according to the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data to obtain the positive-sequence excitation current; calculating the rated capacity of the distribution transformer according to the positive-sequence excitation current and the first positive-sequence synchronous vector operation data. The present invention calculates the rated capacity through the synchronous vector operation data in the operating state of the distribution transformer. The capacity monitoring based on the synchronous vector operation data can realize the online detection of the rated capacity of the distribution transformer, eliminating the cumbersome power outage and test processes, helping to quickly check the performance changes of the distribution transformer, ensuring the long-term stable operation of the distribution transformer, and improving the power supply reliability of the substation area. Description of the Drawings

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0043] Among them:

[0044] Figure 1 It is a schematic flowchart of the on-line detection method for the rated capacity synchronous vector of the distribution transformer in the embodiment of the present invention;

[0045] Figure 2 It is a schematic structural diagram of the on-line detection device for the rated capacity synchronous vector of the distribution transformer in the embodiment of the present invention;

[0046] Figure 3 It is the positive sequence equivalent circuit of the distribution transformer in the embodiment of the present invention;

[0047] Figure 4 It is a structural block diagram of the on-line detection device for the rated capacity synchronous vector of the distribution transformer in the embodiment of the present invention;

[0048] Figure 5 It is the internal structure diagram of the computer device in the embodiment of the present invention. Detailed implementation manners

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0050] To achieve the rapid verification of the rated capacity of the distribution transformer, the present invention proposes an on-line detection method, device and equipment for the rated capacity synchronous vector of the distribution transformer, which can realize the detection of the rated capacity, excitation complex impedance and short-circuit complex impedance of the distribution transformer at the operation site of the distribution transformer, help to quickly check the false capacity marked on the nameplate of the distribution transformer, ensure the correct verification of the electricity price, and can also monitor the operation status of the distribution transformer.

[0051] It can be referred to Figure 1 , Figure 1 It is a schematic flowchart of the on-line detection method for the rated capacity synchronous vector of the distribution transformer in the embodiment of the present invention. The method includes:

[0052] Step 120, synchronously collect the synchronous vector operation data of the high-voltage side and the low-voltage side of the distribution transformer.

[0053] The synchronous vector operation data of the high-voltage side and the low-voltage side of a distribution transformer are important bases for evaluating the performance and state of the distribution transformer. The synchronous vector operation data can include data such as synchronous voltage, current, power, frequency, temperature, load rate, etc. when the distribution transformer is operating.

[0054] In an embodiment of the present invention, data such as the three-phase voltage vectors and three-phase current vectors of the high-voltage side during the operation of the distribution transformer, and the three-phase current vectors of the low-voltage side can be synchronously collected as synchronous vector operation data.

[0055] In an embodiment of the present invention, the synchronous vector operation data of the high-voltage side and the low-voltage side of the distribution transformer can be collected based on an on-line detection device for synchronous vectors of the rated capacity of the distribution transformer. Reference can be made to Figure 2 , Figure 2 is a schematic structural diagram of an on-line detection device for synchronous vectors of the rated capacity of the distribution transformer in an embodiment of the present invention. The on-line detection device for synchronous vectors of the rated capacity of the distribution transformer includes a voltage sensing module 201, a high-voltage current sensor 202, a low-voltage current sensor 203, a synchronous vector measurement module 204, and a calculation module 205. The voltage sensing module 201 is used to convert the high voltage of the high-voltage side of the distribution transformer into a low voltage for easy voltage acquisition; the high-voltage current sensor 202 is used to convert the current of the high-voltage side of the distribution transformer into a low-voltage small current for easy current acquisition; the low-voltage current sensor 203 is used to convert the current of the low-voltage side of the distribution transformer into a small current for easy current acquisition; the synchronous vector measurement module 204 is used to synchronously measure data such as the three-phase voltage vectors and three-phase current vectors of the high-voltage side of the distribution transformer, and the three-phase current vectors of the low-voltage side of the distribution transformer; the calculation module 205 is used to calculate the rated capacity of the distribution transformer according to the synchronous vector operation data of the high-voltage side and the low-voltage side of the distribution transformer.

[0056] Step 140: Based on the symmetrical component method, decompose the synchronous vector operation data of the high-voltage side and the low-voltage side respectively to obtain the first positive-sequence synchronous vector operation data of the high-voltage side and the second positive-sequence synchronous vector operation data of the low-voltage side.

[0057] In an embodiment of the present invention, the synchronous vector operation data such as three-phase current and three-phase voltage are decomposed by the symmetrical component method into positive-sequence, negative-sequence, and zero-sequence components. For example, decomposing the three-phase voltage vectors and three-phase current vectors of the high-voltage side of the distribution transformer obtained in step 120 to obtain the first positive-sequence current and the first positive-sequence voltage of the high-voltage side, and decomposing the three-phase current vectors of the low-voltage side of the distribution transformer to obtain the second positive-sequence current of the low-voltage side.

[0058] Step 160: Calculate the exciting current according to the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data to obtain the positive-sequence exciting current.

[0059] The positive-sequence exciting current is the current generated by a distribution transformer during load operation and can be calculated based on the first positive-sequence synchronous vector operation data on the high-voltage side and the second positive-sequence synchronous vector operation data on the low-voltage side of the distribution transformer.

[0060] Step 180: Calculate the rated capacity of the distribution transformer based on the positive-sequence exciting current and the first positive-sequence synchronous vector operation data.

[0061] In an embodiment of the present invention, a rated capacity calculation formula of the distribution transformer is preset, and the obtained positive-sequence exciting current and the synchronous vector operation data of the distribution transformer are substituted into the rated capacity calculation formula for capacity calculation to obtain the rated capacity of the distribution transformer.

[0062] In an embodiment of the present invention, the synchronous vector operation data in the operating state of the distribution transformer is used to calculate the rated capacity. On the one hand, the real-time parameter changes of the distribution transformer can be analyzed through the synchronous vector operation data, preventing the long-term accumulation of minor faults of the distribution transformer from not being solved, helping to quickly check the performance changes of the distribution transformer, monitor the operating state of the distribution transformer, ensure the long-term stable operation of the distribution transformer, and improve the power supply reliability of the substation area; on the other hand, calculating the rated capacity through the synchronous vector operation data can realize the on-line detection of the rated capacity of the distribution transformer, eliminating the cumbersome power outage and test processes, helping to quickly check the false capacity marked on the nameplate of the distribution transformer, and ensuring the correct verification of the electricity price.

[0063] In an embodiment of the present invention, the synchronous vector operation data at least includes three-phase current vectors, then the positive-sequence synchronous vector operation data at least includes positive-sequence current, that is, the first synchronous vector operation data may include the first positive-sequence current, and the second synchronous vector operation data includes the second positive-sequence current. Based on this, Step 160: Calculate the exciting current according to the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data to obtain the positive-sequence exciting current, which specifically includes:

[0064] Step 610: Reckon the second positive-sequence current on the low-voltage side of the distribution transformer to the high-voltage side of the distribution transformer to obtain the third positive-sequence current reckoned to the high-voltage side.

[0065] In the equivalent circuit of the distribution transformer, the resistance and reactance include the total impedance of the high-voltage winding and the low-voltage winding, and they must be unified to the same side for calculation in the calculation. If calculating the exciting current based on the equivalent circuit of the distribution transformer, it is necessary to make the high-voltage current and the low-voltage current in the same dimension. Therefore, in the present invention, the second positive-sequence current on the low-voltage side can be unified and reckoned to the high-voltage side to calculate the reckoned third positive-sequence current. In another embodiment of the present invention, the first positive-sequence current on the high-voltage side can also be reckoned to the low-voltage side to obtain the third positive-sequence current reckoned to the low-voltage side.

[0066] In an embodiment of the present invention, Step610: Reducing the second positive-sequence current on the low-voltage side of the distribution transformer to the high-voltage side of the distribution transformer to obtain a third positive-sequence current reduced to the high-voltage side, which specifically includes:

[0067] Step611: Obtain the rated voltage ratio and connection group of the distribution transformer at the current operating tap.

[0068] The distribution transformer includes multiple operating taps, and the rated voltages at each operating tap are different, and thus the rated voltage ratios are also different. Therefore, when determining the positive-sequence exciting current of the distribution transformer, it is necessary to obtain the current operating tap of the distribution transformer in advance, and then determine the rated voltage ratio of the distribution transformer at the current operating tap.

[0069] In the embodiment of the present invention, the rated voltage ratio is determined by the ratio of the rated voltages of the high-voltage side and the low-voltage side. The ratio of the rated voltages of the high-voltage side and the low-voltage side can be directly obtained based on the nameplate of the distribution transformer, or can be obtained through measurement and calculation.

[0070] The connection group of the distribution transformer identifies the phase relationship and connection method between the high-voltage side voltage and the low-voltage side voltage of the distribution transformer. The connection group is usually represented by letters and numbers. Common connection groups include Yyn0, Dyn11, Yd11, Yy0, etc. For the letter part, the first letter represents the connection method of the high-voltage side winding, Y represents star connection, and D represents delta connection; the second letter represents the connection method of the low-voltage side winding, y represents star connection, and d represents delta connection, and the third letter represents whether the neutral point is led out, n represents the neutral point is led out, and the number part represents the phase difference of the low-voltage side voltage relative to the high-voltage side voltage. For example, Dyn11 means that the phase voltages of the high-voltage side (D side) and the low-voltage side (y side) are in an 11 o'clock relationship, and the voltage of the y side leads the D side by 30°.

[0071] In the embodiment of the present invention, the connection group of the distribution transformer can be determined by methods such as the winding connection method of the distribution transformer.

[0072] Step612: Determine the rotation factor based on the connection group of the distribution transformer.

[0073] In the embodiment of the present invention, the rotation factor is determined by the connection group of the distribution transformer. Specifically, based on the connection group of the distribution transformer, the angle by which the high-voltage winding leads the low-voltage winding is determined, and based on the angle by which the high-voltage winding leads the low-voltage winding, the rotation factor is determined. The rotation factor can be expressed as where j is the imaginary unit, is the angle by which the high-voltage winding leads the low-voltage winding in the distribution transformer.

[0074] Step613. Perform equivalent calculations based on the rotation factor, the second positive-sequence current, and the rated voltage ratio to obtain the third positive-sequence current obtained by reducing the second positive-sequence current to the high-voltage side.

[0075] In the embodiment of the present invention, the third positive-sequence current is calculated according to the following formula:

[0076]

[0077] In the formula, is the third positive-sequence current, is the second positive-sequence current on the low-voltage side of the distribution transformer, is the rotation factor, where j is the imaginary unit, is the angle by which the high-voltage winding in the distribution transformer leads the low-voltage winding, and k is the rated voltage ratio of the distribution transformer at the current operating tap.

[0078] Step620. Determine the positive-sequence exciting current calculation formula based on the positive-sequence equivalent circuit of the distribution transformer.

[0079] Please refer to Figure 3 , Figure 3 which is the positive-sequence equivalent circuit of the distribution transformer in the embodiment of the present invention. Figure 3 In T R is the total resistance of the high- and low-voltage windings of the distribution transformer, and X T is the total reactance of the high- and low-voltage windings of the distribution transformer. The short-circuit impedance of the distribution transformer is Z T =R T +jX T ; G T is the conductance of the exciting branch of the distribution transformer, and B T is the susceptance of the exciting branch of the distribution transformer. The admittance Y of the exciting branch of the distribution transformer T =G T +jB T ; is the voltage and current on the high-voltage side; is the reduced value of the voltage and current on the low-voltage side to the high-voltage side; is the positive-sequence exciting current.

[0080] Based on Figure 3 the positive-sequence equivalent circuit in

[0081]

[0082] In the formula, is the positive-sequence exciting current, is the first positive-sequence current, is the third positive-sequence current.

[0083] Step630. Substitute the third positive-sequence current and the first positive-sequence current on the high-voltage side of the distribution transformer into the positive-sequence exciting current calculation formula for calculation to obtain the positive-sequence exciting current.

[0084] After obtaining the positive-sequence exciting current calculation formula, substitute the first positive-sequence current and the third positive-sequence current calculated based on Step613 into the positive-sequence exciting current calculation formula for calculation to obtain the positive-sequence exciting current, that is, calculate the difference between the first positive-sequence current and the third positive-sequence current.

[0085] In an embodiment of the present invention, the synchronous vector operation data further includes three-phase voltage vectors, then the positive-sequence synchronous vector operation data further includes positive-sequence voltages, that is, the first positive-sequence synchronous vector operation data includes the first positive-sequence voltage in addition to the first positive-sequence current. Based on this, Step180. Calculate the rated capacity of the distribution transformer according to the positive-sequence exciting current and the first positive-sequence synchronous vector operation data, specifically including:

[0086] Step810. Obtain the no-load current percentage of the distribution transformer and the rated voltage on the high-voltage side.

[0087] In the implementation of the present invention, the no-load current percentage of the distribution transformer and the rated voltage on the high-voltage side can be directly obtained based on the nameplate of the distribution transformer.

[0088] Step820. Perform capacity calculation according to the no-load current percentage, rated voltage, the first positive-sequence voltage on the high-voltage side of the distribution transformer, and the positive-sequence exciting current to obtain the rated capacity of the distribution transformer.

[0089] In an embodiment of the present invention, the rated capacity of the distribution transformer is calculated according to the following formula:

[0090]

[0091] In the formula, S N is the rated capacity of the distribution transformer, imag() is the imaginary part extraction function, is the positive-sequence exciting current, is the first positive-sequence voltage on the high-voltage side of the distribution transformer, U N is the rated voltage on the high-voltage side of the distribution transformer, and I0% is the no-load current percentage of the distribution transformer.

[0092] The present invention realizes the on-line detection of the rated capacity of a distribution transformer based on the synchronous vector operation data of the distribution transformer, eliminating the cumbersome power outage and testing processes, which helps to quickly check the performance changes of the distribution transformer, ensure the long-term stable operation of the distribution transformer, improve the power supply reliability of the substation area. In addition, through the synchronous vector operation data, the real-time parameter changes of the distribution transformer can be analyzed. For example, the impedance parameters of the distribution transformer can be detected at the operation site of the distribution transformer, the internal minor damages of the distribution transformer can be found, and the long-term accumulation of minor faults of the distribution transformer can be prevented from not being solved, providing a fast and simple method for the maintenance test of the distribution transformer, improving the test efficiency of the on-site test of the distribution transformer, and helping the safe and stable operation of the distribution transformer.

[0093] In an embodiment of the present invention, an on-line detection device for the rated capacity of a distribution transformer is also proposed, which can be referred to Figure 4 , Figure 4 is the structural block diagram of the on-line detection device for the rated capacity of the distribution transformer in the embodiment of the present invention. The on-line detection device includes a parameter measurement module 401, a parameter processing module 402, and a capacity calculation module 403.

[0094] The parameter measurement module 401 is used to synchronously collect the synchronous vector operation data of the high-voltage side and the low-voltage side of the distribution transformer.

[0095] The parameter processing module 402 is used to decompose the synchronous vector operation data of the high-voltage side and the low-voltage side respectively based on the symmetrical component method to obtain the first positive-sequence synchronous vector operation data of the high-voltage side and the second positive-sequence synchronous vector operation data of the low-voltage side.

[0096] The capacity calculation module 403 is used to calculate the exciting current according to the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data to obtain the positive-sequence exciting current; and calculate the rated capacity of the distribution transformer according to the positive-sequence exciting current and the first positive-sequence synchronous vector operation data.

[0097] In the embodiment of the present invention, the parameter measurement module 401 includes a voltage sensing module 201, a high-voltage current sensor 202, a low-voltage current sensor 203, and a synchronous vector measurement module 204. The voltage sensing module 201 is used to convert the high voltage of the high-voltage side of the distribution transformer into a low voltage for easy voltage acquisition; the high-voltage current sensor 202 is used to convert the current of the high-voltage side of the distribution transformer into a low-voltage small current for easy current acquisition; the low-voltage current sensor 203 is used to convert the current of the low-voltage side of the distribution transformer into a small current for easy current acquisition; the synchronous vector measurement module 204 is used to synchronously measure data such as the three-phase voltage vectors and three-phase current vectors of the high-voltage side of the distribution transformer and the three-phase current vectors of the low-voltage side of the distribution transformer.

[0098] The capacity calculation module 403 is configured to convert the second positive-sequence current on the low-voltage side of the distribution transformer to the high-voltage side of the distribution transformer to obtain a third positive-sequence current converted to the high-voltage side; determine a positive-sequence exciting current calculation formula based on the positive-sequence equivalent circuit of the distribution transformer; substitute the third positive-sequence current and the first positive-sequence current on the high-voltage side of the distribution transformer into the positive-sequence exciting current calculation formula for calculation to obtain the positive-sequence exciting current.

[0099] The capacity calculation module 403 is further configured to obtain the rated voltage ratio and connection group of the distribution transformer at the current operating tap; determine a rotation factor based on the connection group of the distribution transformer; perform equivalent calculation according to the rotation factor, the second positive-sequence current, and the rated voltage ratio to obtain a third positive-sequence current obtained by converting the second positive-sequence current to the high-voltage side.

[0100] The capacity calculation module 403 is further configured to obtain the no-load current percentage of the distribution transformer and the rated voltage on the high-voltage side; perform capacity calculation according to the no-load current percentage, the rated voltage, the first positive-sequence voltage on the high-voltage side of the distribution transformer, and the positive-sequence exciting current to obtain the rated capacity of the distribution transformer.

[0101] In an embodiment of the present invention, the rated capacity is calculated through the synchronous vector operation data of the distribution transformer during operation. On the one hand, the real-time parameter changes of the distribution transformer can be analyzed through the synchronous vector operation data, preventing the long-term accumulation of minor faults of the distribution transformer from not being solved, helping to quickly check the performance changes of the distribution transformer, monitor the operation state of the distribution transformer, ensure the long-term stable operation of the distribution transformer, and improve the power supply reliability of the substation area. On the other hand, by calculating the rated capacity through the synchronous vector operation data, the on-line detection of the rated capacity of the distribution transformer can be realized, eliminating the cumbersome power outage and test processes, helping to quickly check the false capacity marked on the nameplate of the distribution transformer, and ensuring the correct verification of the electricity price.

[0102] Figure 5 The internal structure diagram of a computer device in an embodiment of the present invention is shown. The computer device may specifically be a terminal or a system. As Figure 5 shown, the computer device includes a processor, a memory, and a network interface connected through a system bus. Among them, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement each step in the above method embodiment. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can execute each step in the above method embodiment. Those skilled in the art can understand that Figure 5The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. Specifically, the computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0103] In one embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor is caused to execute each step in the above method embodiment.

[0104] In one embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by the processor, the processor is caused to execute each step in the above method embodiment.

[0105] Those of ordinary skill in the art can understand that all or part of the processes of implementing the above method embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it may include the processes of the above method embodiments. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0106] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0107] The above embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. An on-line detection method for synchronous vectors of the rated capacity of a distribution transformer, characterized in that, The method includes: Synchronously collecting the synchronous vector operation data of the high-voltage side and the low-voltage side of the distribution transformer; Based on the symmetrical component method, decomposing the synchronous vector operation data of the high-voltage side and the low-voltage side respectively to obtain the first positive-sequence synchronous vector operation data of the high-voltage side and the second positive-sequence synchronous vector operation data of the low-voltage side; Calculating the exciting current according to the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data to obtain the positive-sequence exciting current; Calculating the rated capacity of the distribution transformer according to the positive-sequence exciting current and the first positive-sequence synchronous vector operation data.

2. The method according to claim 1, characterized in that, The positive-sequence synchronous vector operation data at least includes positive-sequence current; Then, the calculating the exciting current according to the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data to obtain the positive-sequence exciting current specifically includes: Reducing the second positive-sequence current of the low-voltage side of the distribution transformer to the high-voltage side of the distribution transformer to obtain the third positive-sequence current reduced to the high-voltage side; Determining the positive-sequence exciting current calculation formula based on the positive-sequence equivalent circuit of the distribution transformer; Substituting the third positive-sequence current and the first positive-sequence current of the high-voltage side of the distribution transformer into the positive-sequence exciting current calculation formula for calculation to obtain the positive-sequence exciting current.

3. The method according to claim 2, wherein The reducing the second positive-sequence current of the low-voltage side of the distribution transformer to the high-voltage side of the distribution transformer to obtain the third positive-sequence current reduced to the high-voltage side specifically includes: Obtaining the rated voltage ratio and the connection group of the distribution transformer at the current operating tap; Determining the rotation factor based on the connection group of the distribution transformer; Performing equivalent calculation according to the rotation factor, the second positive-sequence current and the rated voltage ratio to obtain the third positive-sequence current of the second positive-sequence current reduced to the high-voltage side.

4. The method according to claim 3, wherein The third positive-sequence current is calculated according to the following formula: In the formula, is the third positive sequence current mentioned above, is the second positive sequence current on the low voltage side of the distribution transformer mentioned above, is the rotation factor, where j is the imaginary unit, is the angle by which the high voltage winding of the distribution transformer leads the low voltage winding, and k is the rated voltage ratio of the distribution transformer at the current operating tap position.

5. The method according to claim 2, wherein The positive-sequence exciting current is calculated through the following formula: In the formula, is the positive-sequence exciting current mentioned above, is the first positive-sequence current, is the third positive-sequence current.

6. The method according to claim 2, wherein The positive-sequence synchronous vector operation data further includes positive-sequence voltage; Then, the calculating the rated capacity of the distribution transformer according to the positive-sequence exciting current and the first positive-sequence synchronous vector operation data specifically includes: Obtaining the no-load current percentage of the distribution transformer and the rated voltage of the high-voltage side; Performing capacity calculation according to the no-load current percentage, the rated voltage, the first positive-sequence voltage of the high-voltage side of the distribution transformer, and the positive-sequence exciting current to obtain the rated capacity of the distribution transformer.

7. The method according to claim 6, characterized in that, The rated capacity of the distribution transformer is calculated according to the following formula: Wherein, S N is the rated capacity of the distribution transformer, imag() is the function of taking the imaginary part, is the positive-sequence exciting current, is the first positive-sequence voltage on the high-voltage side of the distribution transformer, U N is the rated voltage on the high-voltage side of the distribution transformer, and I0% is the no-load current percentage of the distribution transformer.

8. An on-line detection device for synchronous vectors of the rated capacity of a distribution transformer, characterized in that, The on-line detection device includes a parameter measurement module, a parameter processing module, and a capacity calculation module; The parameter measurement module is used to synchronously collect the synchronous vector operation data of the high-voltage side and the low-voltage side of the distribution transformer; The parameter processing module is used to decompose the synchronous vector operation data of the high-voltage side and the low-voltage side respectively based on the symmetrical component method to obtain the first positive-sequence synchronous vector operation data of the high-voltage side and the second positive-sequence synchronous vector operation data of the low-voltage side; The capacity calculation module is configured to calculate the excitation current based on the first positive-sequence synchronous vector operation data and the second positive-sequence synchronous vector operation data to obtain the positive-sequence excitation current; The rated capacity of the distribution transformer is calculated based on the positive-sequence excitation current and the first positive-sequence synchronous vector operation data.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, the processor is caused to execute the steps of the method according to any one of claims 1 to 7.

10. A computer device, comprising a memory and a processor, characterized in that, The memory stores a computer program, and when the computer program is executed by the processor, the processor is caused to execute the steps of the method according to any one of claims 1 to 7.

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