Low-voltage current balance mechanism for box-type transformer substation temperature rise test and prefabricated transformer substation

Abstract

The invention discloses a low-voltage current balance mechanism for a temperature rise test of a box transformer substation and a prefabricated substation, the balance mechanism comprises a connecting piece, one end of the connecting piece is connected with a low-voltage side of the box transformer substation, and the other end is connected with a low-voltage large-current test system; wherein one side, connected with the connecting piece, of the low-voltage side of the box transformer substation is provided with a plurality of fixed ends, each fixed end is a three-phase fixed end, and one end, far away from the low-voltage large-current test system, of the connecting piece is divided into a plurality of branches and is connected with the plurality of fixed ends; the current balancing devices and the first current measuring pieces are arranged on the multiple branches, and each branch is provided with one current balancing device and one first current measuring piece. The current balancing device is arranged on each branch, so that the current flowing through each branch can be accurately adjusted, the current of each branch on the low-voltage side of the box transformer substation is ensured to meet an expected required value in a temperature rise test, and the problems of equipment overheating, damage and the like caused by current imbalance can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of substation current balancing, and in particular relates to a low-voltage current balancing mechanism for a box-type transformer temperature rise test and a prefabricated substation. Background Art

[0002] The temperature rise test of prefabricated substation is a very important test in its type test. In fact, the purpose of the test is to assess whether the heat dissipation performance of the prefabricated substation will not shorten the expected life of its internal components during normal operation. The temperature rise test to verify the main components in the prefabricated substation is one of the mandatory type test items of the prefabricated substation.

[0003] The test method is specified in the standard GB / T17467-2020. The preferred test method requires the use of two independent current sources to supply power to the high-voltage side and the low-voltage side of the substation. The low-voltage side requires that the low-voltage connection line be disconnected and short-circuited from the transformer as close to the transformer terminal as possible, and the test current is applied to the low-voltage switchgear through the low-voltage outlet terminal.

[0004] According to the provisions of standard GB / T17467-2020, the low-voltage rated current of the test sample needs to be applied to the low-voltage side. This current is directly applied to the low-voltage outgoing terminal through a low-voltage high-current generating device. Since there are multiple branches on the low-voltage side of the substation, the loop resistance of each branch is different due to its design, resulting in large differences in the current of each branch, and the current of each branch cannot be effectively controlled.

[0005] At present, according to the standard, the low-voltage side of the box transformer temperature rise test requires that the low-voltage connecting line be disconnected and short-circuited from the transformer as close to the transformer terminal as possible, and a low-voltage rated current be applied. The current is directly applied to the low-voltage terminal through a low-voltage high-current generator. The existing technical solution usually connects a load resistor box in series in the loop to achieve the purpose of increasing the loop impedance and reducing the loop current. However, the existing test device can usually only control the size of the total current through the power supply, but cannot control the size of each branch current, and the branch switch tripping phenomenon often occurs. The current of the branch loop is generally controlled by connecting a load resistor box in series to increase the loop impedance and reduce the current. However, since the low-voltage side loop of the box transformer temperature rise test is usually not long, the load resistor box is generally located close to the box transformer test product. During the test, the heating of the load box will affect the measurement of the ambient temperature around the box transformer, and then affect the measurement of the box transformer temperature rise, affecting the test efficiency and accuracy. Summary of the invention

[0006] The purpose of the present invention is to provide a low-voltage current balancing mechanism and a prefabricated substation for a box-type transformer temperature rise test, so as to solve the technical defects in the prior art that the total current can only be controlled by a power supply, and the current of each branch cannot be controlled, resulting in the tripping of each branch switch, or when a load resistor box is used to adjust the branch current, the heat generated by the load resistor box will affect the measurement of the ambient temperature around the box-type transformer, thereby affecting the measurement of the temperature rise of the box-type transformer and affecting the test efficiency and accuracy.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, a low-voltage current balancing mechanism for a box-type transformer temperature rise test is provided, comprising: A connector, one end of which is connected to the low-voltage side of the box-type transformer, and the other end of which is connected to a low-voltage and high-current test system; wherein the side of the box-type transformer low-voltage side connected to the connector has a plurality of fixed ends, each of which is a three-phase fixed end, and the end of the connector away from the low-voltage and high-current test system is divided into a plurality of branches and connected to the plurality of fixed ends; A current balancing device and a first current measuring component are arranged on a plurality of branches of the connecting component, and one current balancing device and one first current measuring component are arranged on each branch, and the current balancing device is used to adjust the current on the branch; The first current measuring component is used to measure the current on the branch line and transmit the measurement signal to the low-voltage and high-current test system.

[0008] Furthermore, the current balancing device comprises a box and a magnetic member, wherein the box is a hollow structure and is provided with a mounting hole; The connecting member is arranged in the mounting hole, and the magnetic member is wound around the outside of the connecting member to change the loop impedance of the connecting member.

[0009] Furthermore, a knob is provided on the top of the box, and the end of the knob extends into the box; One end of the magnetic piece is wound around the outside of the connecting piece, and the other end is connected to the end of the knob, and the knob is used to adjust the number of layers of the magnetic piece.

[0010] Furthermore, a binding piece is provided on the magnetic piece.

[0011] Furthermore, the magnetic member is a silicon steel sheet.

[0012] Furthermore, the current balancing device comprises a box body and a suspension member, wherein the box body is a hollow structure and is provided with a mounting hole; The connecting member is arranged in the mounting hole, the hanging member is arranged outside the connecting member, and a coil is arranged on the hanging member.

[0013] Furthermore, the hanging member is a through-core iron core or an iron ring.

[0014] Furthermore, the connecting piece is a three-phase cable, one end of which is divided into three branches and connected to the low-voltage side of the box-type transformer, and the other end is connected to the low-voltage and high-current test system.

[0015] Furthermore, the low-voltage and high-current test system includes a voltage regulator, a current booster, a second current measuring device and a control device, wherein the voltage regulator, the current booster, the second current measuring device and the control device are connected in sequence, and the voltage regulator is connected to the connecting device.

[0016] In a second aspect, a prefabricated substation is provided, including a substation body, on which a low-voltage side is provided, and on which the low-voltage current balancing mechanism for the temperature rise test of the box-type transformer as described above is installed.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. By setting a current balancing device on each connector, the mechanism can accurately adjust the current flowing through each connector to ensure that the current distribution in the three-phase connection on the low-voltage side of the box-type transformer is more in line with the expected requirements, which helps to reduce problems such as equipment overheating and damage caused by current imbalance, and will not affect the ambient temperature of the box-type transformer temperature rise test, thereby improving the accuracy and safety of the test. On the one hand, it solves the heating problem caused by the load resistance box used in the prior art for testing. On the other hand, the current balancing device can accurately monitor the current of each branch circuit, avoiding the tripping problem caused by branch current imbalance during the test, thereby improving the test efficiency.

[0018] 2. By wrapping the magnetic parts around the outside of the connector, the current balancing device can change the loop impedance of the connector and flexibly adjust the current flowing through the connector, thereby achieving precise control of the current in the three-phase connection on the low-voltage side of the box-type transformer, which is crucial to ensuring the uniformity of current distribution and the accuracy of the test.

[0019] 3. The knob setting can adjust the number of layers of the magnetic part wrapped around the connector by simply rotating it. This adjustment method is intuitive and easy to operate, which greatly simplifies the current adjustment process and improves the efficiency and convenience of the test. Secondly, by adjusting the number of winding layers of the magnetic part, the loop impedance of the connector can be accurately changed, thereby achieving precise control of the current.

[0020] 4. The main function of the binding is to fix the magnetic parts to prevent them from loosening or falling off due to vibration or external force during operation. It helps to maintain the stability and reliability of the current balancing device and ensure that the magnetic parts can continuously and effectively change the loop impedance of the connector.

[0021] 5. Silicon steel sheets have high magnetic permeability and can efficiently conduct magnetic fields. In current balancing devices, silicon steel sheets, as magnetic parts, can effectively change the loop impedance of the connector, thereby achieving precise regulation of the current.

[0022] 6. The coil provided on the suspension part can be used as an adjustable inductor element. By changing the current passing through the coil, the loop impedance on the connecting part can be flexibly adjusted to achieve precise regulation of the current.

[0023] 7. The through-core is used as a suspension part, and a closed magnetic circuit can be formed inside it, making the magnetic field more concentrated and efficient, which helps to reduce the leakage and dispersion of the magnetic field and improve the performance of the loop regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic diagram of the operation of a low-voltage current balancing mechanism for a box-type transformer temperature rise test provided by the present invention; Figure 2 A schematic diagram of a passive current balancing device in a low-voltage current balancing mechanism for a box-type transformer temperature rise test provided by the present invention; Figure 3 A schematic diagram of an active current balancing device in a low-voltage current balancing mechanism for a box-type transformer temperature rise test provided by the present invention; Wherein: 1. Current balancing device; 101. Box body; 102. Mounting hole; 103. Magnetic part; 104. Binding part; 105. Knob; 106. Suspension part; 107. Coil; 2. First current measuring part; 3. Low-voltage and high-current test system; 4. Low-voltage side of box-type transformer. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0029] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0030] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0031] The temperature rise test of prefabricated substation is a very important test in its type test. In fact, the purpose of the test is to assess whether the heat dissipation performance of the prefabricated substation will not shorten the expected life of its internal components during normal operation. The temperature rise test to verify the main components in the prefabricated substation is one of the mandatory type test items of the prefabricated substation.

[0032] The test method is specified in the standard GB / T17467-2020. The preferred test method requires the use of two independent current sources to supply power to the high-voltage side and the low-voltage side of the substation. The low-voltage side requires that the low-voltage connection line be disconnected and short-circuited from the transformer as close to the transformer terminal as possible, and the test current is applied to the low-voltage switchgear through the low-voltage outlet terminal.

[0033] According to the provisions of standard GB / T17467-2020, the low-voltage rated current of the test sample needs to be applied to the low-voltage side. This current is directly applied to the low-voltage outgoing terminal through a low-voltage high-current generating device. Since there are multiple branches on the low-voltage side of the substation, the loop resistance of each branch is different due to its design, resulting in large differences in the current of each branch, and the current of each branch cannot be effectively controlled.

[0034] At present, according to the standard, the low-voltage side of the box transformer temperature rise test requires that the low-voltage connecting line be disconnected and short-circuited from the transformer as close to the transformer terminal as possible, and a low-voltage rated current be applied. The current is directly applied to the low-voltage terminal through a low-voltage high-current generator. The existing technical solution usually connects a load resistor box in series in the loop to achieve the purpose of increasing the loop impedance and reducing the loop current. However, the existing test device can usually only control the size of the total current through the power supply, but cannot control the size of each branch current, and the branch switch tripping phenomenon often occurs. The current of the branch loop is generally controlled by connecting a load resistor box in series to increase the loop impedance and reduce the current. However, since the low-voltage side loop of the box transformer temperature rise test is usually not long, the load resistor box is generally located close to the box transformer test product. During the test, the heating of the load box will affect the measurement of the ambient temperature around the box transformer, and then affect the measurement of the box transformer temperature rise, affecting the test efficiency and accuracy.

[0035] In order to solve the above technical defects, the inventor provides a low-voltage current balancing mechanism for temperature rise test of box-type transformer and a prefabricated substation.

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings: First, as Figure 1-Figure 3 As shown, an embodiment of the present invention provides a low-voltage current balancing mechanism for a box-type transformer temperature rise test, comprising: a connector, one end of which is connected to the box-type transformer low-voltage side 4, and the other end is connected to a low-voltage and high-current test system 3; wherein, the box-type transformer low-voltage side 4 has a plurality of fixed ends on one side connected to the connector, each of which is a three-phase fixed end, and the end of the connector away from the low-voltage and high-current test system 3 is divided into a plurality of branches and connected to the plurality of fixed ends; a current balancing device 1 and a first current measuring device 2 are arranged on a plurality of branches of the connector, and a current balancing device 1 and a first current measuring device 2 are arranged on each branch, and the current balancing device 1 is used to adjust the current on the branch; the first current measuring device 2 is used to measure the current on the branch and transmit the measurement signal to the low-voltage and high-current test system 3. Since the connector is a three-phase cable, one end of the three-phase cable is divided into three branches, connected to the box-type transformer low-voltage side 4, and the other end is connected to the low-voltage and high-current test system 3.

[0037] When the prefabricated substation is subjected to a temperature rise test using the low-voltage current balancing mechanism, a current balancing device 1 is provided on each branch of the connector. The mechanism can accurately adjust the current flowing through each branch to ensure that the current distribution in the three-phase connection on the low-voltage side 4 of the box transformer is more in line with the expected requirements, which helps to reduce problems such as equipment overheating and damage caused by current imbalance, and will not affect the ambient temperature of the box transformer temperature rise test, thereby improving the accuracy and safety of the test. On the one hand, it solves the heating problem caused by the load resistance box used in the prior art for testing. On the other hand, the current balancing device 1 can accurately monitor the current of each branch circuit, thereby avoiding the tripping problem caused by branch current imbalance during the test and improving the test efficiency.

[0038] like Figure 2 As shown, the current balancing device 1 includes a box 101 and a magnetic member 103. The box 101 is a hollow structure, and a mounting hole 102 is provided on it. The connector is arranged in the mounting hole 102, and the magnetic member 103 is wound around the outside of the connector to change the loop impedance of the connector. In this process, by winding the magnetic member 103 around the outside of the connector, the current balancing device 1 can change the loop impedance of the connector, and can flexibly adjust the current flowing through the connector, thereby realizing accurate control of the current in the three-phase connection of the low-voltage side 4 of the box transformer, which is crucial to ensure the uniformity of current distribution and the accuracy of the test. Secondly, since the box 101 adopts a hollow structure design and a mounting hole 102 is provided, it is convenient to pass the connector through and fix it. This design not only makes the structure of the current balancing device 1 more compact, but also simplifies the installation process and reduces the installation cost. At the same time, since the box 101 has a certain protective effect, the service life of the connector and the magnetic member 103 can also be improved. Moreover, by precisely adjusting the current distribution, the current balancing device 1 helps to reduce problems such as equipment overheating and damage caused by current imbalance, which not only improves the safety of the test, but also ensures the stability of the test process. In addition, since the magnetic part 103 can change the loop impedance, it can also suppress current fluctuations to a certain extent, further improving the accuracy of the test results. Finally, it is worth noting that the design of the current balancing device 1 in this scheme allows it to adapt to different types of connectors and test requirements. It is only necessary to select the appropriate magnetic part 103 and adjust its winding method according to the specific test requirements. This flexibility improves the overall versatility and practicality of the low-voltage current balancing mechanism. Moreover, since the structure of the box 101 is relatively simple and easy to disassemble and clean, it is also convenient for subsequent maintenance and maintenance work.

[0039] Furthermore, if Figure 2As shown, a knob 105 is provided on the top of the box 101, and the end of the knob 105 extends into the box 101. One end of the magnetic member 103 is wound around the outside of the connector, and the other end is connected to the end of the knob 105. The knob 105 is used to adjust the number of layers of the magnetic member 103. In this solution, a spring assembly is provided inside the box 101. The spring assembly is a prior art product and can be purchased directly on the market. The installation of the spring assembly allows the magnetic member 103 to be wound around the outside of the connector like a spring. Through cooperation with the knob 105, during the test operation, the number of layers of the magnetic member 103 wound around the connector can be adjusted by simply rotating. This adjustment method is intuitive and easy to operate, which greatly simplifies the process of current adjustment and improves the efficiency and convenience of the test. Secondly, by adjusting the number of winding layers of the magnetic member 103, the loop impedance of the connector can be accurately changed, thereby achieving accurate control of the current. In addition, the knob 105 is located at the top of the box 101, which is easy to observe and operate, and can conveniently check and adjust the state of the current balancing device 1 to ensure the smooth progress of the test. At the same time, since the knob 105 provides a convenient current adjustment method, the test can be completed without purchasing additional current adjustment equipment or tools, which reduces the overall cost of the test equipment and improves the economy of the test.

[0040] like Figure 2 As shown, further, a binding member 104 is provided on the magnetic member 103. The magnetic member 103 is preferably a silicon steel sheet. The silicon steel sheet has a high magnetic permeability and can efficiently conduct the magnetic field. In the current balancing device 1, the silicon steel sheet is used as the magnetic member 103, which can effectively change the loop impedance of the connecting member, thereby achieving accurate regulation of the current. The binding member 104 is preferably an iron wire. The main function of the binding member 104 is to fix the magnetic member 103 to prevent it from loosening or falling off due to vibration or external force during operation, which helps to maintain the stability and reliability of the current balancing device 1 and ensure that the magnetic member 103 can continuously and effectively change the loop impedance of the connecting member. At the same time, by tightly fixing the magnetic member 103 to the connecting member through the binding member 104, good contact between the magnetic member 103 and the connecting member can be ensured, which helps to reduce the current regulation error caused by poor contact and improve the accuracy and precision of the current regulation. Furthermore, the addition of the binding member 104 can enhance the overall structural strength of the current balancing device 1. When working for a long time or bearing a large current, the binding member 104 can prevent the magnetic member 103 from being deformed or damaged due to excessive force, thereby extending the service life of the current balancing device 1. In terms of installation and removal, the magnetic member 103 and the binding member 104 can be easily installed or removed by using appropriate tools and methods for maintenance, replacement or adjustment, thereby improving the flexibility and maintainability of the current balancing device 1.

[0041] like Figure 3As shown, in this scheme, in another embodiment, the current balancing device 1 includes a box 101 and a suspension member 106. The box 101 is a hollow structure, and a mounting hole 102 is opened on it. The connecting member is arranged in the mounting hole 102, and the suspension member 106 is arranged outside the connecting member. A coil 107 is arranged on the suspension member 106; the coil 107 arranged on the suspension member 106 can be used as an adjustable inductance element. By changing the current passing through the coil 107, the current distribution on the connecting member can be flexibly adjusted to achieve accurate current balance, so that the current balancing device 1 can adapt to different test requirements and current changes, and improve the accuracy and reliability of the test. The suspension member 106 is a through-core iron core or an iron ring, and the material is a silicon steel sheet, a magnetic material. The coil 107 installed on the suspension member 106 can apply current. By changing the current passing through the coil 107, the current distribution on the connecting member can be accurately adjusted to achieve accurate control of the branch current, and improve the accuracy and reliability of the test. The suspension member 106 and the coil 107 can be tightly assembled together and can be disassembled and replaced as a whole, which simplifies the installation process and reduces the installation cost.

[0042] In addition, the coil 107 can control the loop impedance of the connector through the coil current size, and realize the automation of test current control through automatic control. This function can be achieved through system automation and intelligence, which can reduce labor costs and improve test efficiency.

[0043] Finally, the cooperation between the suspension 106 and the coil 107 enables the current balancing device 1 to better adapt to the change of current and reduce the problems of equipment overheating and damage caused by current imbalance; and the number of turns or access mode of the coil 107 can be adjusted through simple operations, so that the current balancing device 1 can quickly adapt to different test requirements and current changes. Due to the design of the suspension 106 and the coil 107, the current balancing device 1 has flexible current adjustment capabilities and is easy to install, so it is suitable for various types and specifications of power equipment tests.

[0044] like Figure 3As shown, in this solution, the suspension member 106 is a through-core or iron ring. When the through-core is used as the suspension member 106, a closed magnetic circuit can be formed inside it, making the magnetic field more concentrated and efficient, reducing the leakage and dispersion of the magnetic field, and improving the performance of the current balancing device 1; at the same time, the through-core makes the structure of the current balancing device 1 more compact and stable, and can be directly suspended on the connector without the need for an additional supporting structure, thereby saving space and cost. When the iron ring is used as the suspension member 106, a ring-shaped magnetic field can also be formed inside it, which helps to enhance the magnetic field effect of the current balancing device 1, and can make the current more evenly distributed on the connector, improving the performance of the current balancing device 1; moreover, the iron ring has good electrical conductivity and thermal conductivity, and can quickly transfer current and heat, so that the current balancing device 1 can maintain stable performance when working for a long time or under high load.

[0045] like Figure 1 As shown, the low-voltage and high-current test system 3 includes a voltage regulator, a current booster, a second current measuring device and a control device. The voltage regulator, the current booster, the second current measuring device and the control device are connected in sequence, and the voltage regulator is connected to the connecting device. In this solution, the first current measuring device 2 and the second current measuring device are preferably current transformers. During the test, the main function of the system is, on the one hand, to provide the low-voltage rated current required for the low-voltage side of the box transformer temperature rise test, and on the other hand, to provide the current control function of the active current balancing device 1; in the low-voltage and high-current test system 3, the voltage regulator can accurately adjust the output voltage and provide a stable input voltage for the current booster, thereby ensuring the stability and accuracy of the output current. The second current measuring device can monitor the current value in real time and provide accurate current data for the control device to analyze and adjust; and during the test, the current booster can quickly and smoothly increase the current to meet the needs of the low-voltage and high-current test.

[0046] On the second aspect, an embodiment of the present invention provides a prefabricated substation, including a substation body, on which a low-voltage side is provided, and on which a low-voltage current balancing mechanism for the temperature rise test of a box-type transformer as described above is installed. The prefabricated substation adopts the low-voltage current balancing mechanism provided by this solution, which can not only avoid problems such as overheating and damage of equipment caused by current imbalance during the temperature rise test, but also accurately monitor the current of each branch circuit through the current balancing device 1, thereby avoiding tripping problems caused by branch current imbalance during the test, thereby improving the test efficiency.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the pending claims of the invention.

Claims

1. A low voltage current balancing mechanism for box transformer temperature rise test, characterized in that: include: A connector, one end of which is connected to the low-voltage side (4) of the box-type transformer, and the other end of which is connected to the low-voltage and high-current test system (3); wherein the side of the box-type transformer low-voltage side (4) connected to the connector has a plurality of fixed ends, each of which is a three-phase fixed end, and the end of the connector away from the low-voltage and high-current test system (3) is divided into a plurality of branches and connected to the plurality of fixed ends; A current balancing device (1) and a first current measuring element (2) are arranged on a plurality of branches of the connecting element, and each branch is provided with one current balancing device (1) and one first current measuring element (2), the current balancing device (1) being used to adjust the current on the branch; The first current measuring component (2) is used to measure the current on the branch line and transmit the measurement signal to the low-voltage and high-current test system (3).

2. The low-voltage current balancing mechanism for box-type transformer temperature rise test according to claim 1 is characterized in that: The current balancing device (1) comprises a box (101) and a magnetic member (103); the box (101) is a hollow structure and is provided with a mounting hole (102); The connecting piece is arranged in the mounting hole (102), and the magnetic piece (103) is wound around the outside of the connecting piece to change the loop impedance of the connecting piece.

3. The low-voltage current balancing mechanism for box-type transformer temperature rise test according to claim 2, characterized in that: A knob (105) is provided on the top of the box body (101), and an end of the knob (105) extends into the box body (101); One end of the magnetic member (103) is wound around the outside of the connecting member, and the other end is connected to the end of a knob (105), and the knob (105) is used to adjust the number of layers of winding of the magnetic member (103).

4. The low-voltage current balancing mechanism for box-type transformer temperature rise test according to claim 2 or 3, characterized in that: A binding piece (104) is provided on the magnetic piece (103).

5. The low-voltage current balancing mechanism for box-type transformer temperature rise test according to any one of claims 2 to 4, characterized in that: The magnetic component (103) is a silicon steel sheet.

6. The low-voltage current balancing mechanism for box-type transformer temperature rise test according to claim 2, characterized in that: The current balancing device (1) comprises a box (101) and a suspension member (106); the box (101) is a hollow structure and is provided with a mounting hole (102); The connecting member is arranged in the mounting hole (102), the hanging member (106) is arranged outside the connecting member, and a coil (107) is provided on the hanging member (106).

7. The low-voltage current balancing mechanism for box-type transformer temperature rise test according to claim 6, characterized in that: The hanging member (106) is a through-core iron core or an iron ring.

8. The low-voltage current balancing mechanism for box-type transformer temperature rise test according to claim 1, characterized in that: The connecting piece is a three-phase cable, one end of which is divided into three branches and connected to the low-voltage side (4) of the box-type transformer, and the other end of which is connected to the low-voltage and high-current test system (3).

9. The low-voltage current balancing mechanism for box-type transformer temperature rise test according to claim 1 or 8, characterized in that: The low-voltage and high-current test system (3) comprises a voltage regulator, a current booster, a second current measuring device and a control device, wherein the voltage regulator, the current booster, the second current measuring device and the control device are connected in sequence, and the voltage regulator is connected to the connecting device.

10. A prefabricated substation, comprising a substation body, on which a low voltage side is arranged, characterized in that: The low-voltage side is installed with a low-voltage current balancing mechanism for the box-type transformer temperature rise test as described in any one of claims 1 to 9.

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