Transformer outgoing line sleeve device, transformer and use method

Abstract

The invention discloses a transformer outgoing line sleeve device, a transformer and a using method. The transformer outgoing line sleeve device comprises a mounting seat, an oil-oil sleeve, a cable terminal and a test terminal. One end of the oil-oil sleeve is provided with a wiring terminal, the other end of the oil-oil sleeve is electrically connected with the transformer winding, and the wiring terminal is located between the cable terminal and the test terminal. The test terminal is electrically connected with the wiring terminal through the first current-carrying lead, the test terminal has a first state or a second state, when the test terminal is in the first state, the test terminal is used for applying a test voltage to the transformer so as to carry out a high-voltage test on the transformer, and when the test terminal is in the second state, the test terminal stops applying the voltage to the transformer. And the cable terminal is electrically connected with the wiring terminal through a second current-carrying lead and is used for performing power input / output on the transformer when the test terminal is in a second state. The transformer wire outlet device can conveniently perform high-voltage test on the transformer, and can be quickly put into operation after the test is finished.

Description

Technical Field

[0001] The invention relates to a transformer outlet bushing device, a transformer comprising the device and a method for using the device. Background Art

[0002] With the development of electric power, oil-oil bushing cable terminal outlet application scenarios are increasing, such as: indoor substation, offshore wind power and other projects; its advantage is that the substation occupies a small area, and its disadvantage is that there are many disadvantages when testing the transformer. Specifically, oil-oil bushing is a type of cable outlet bushing in the transformer. Usually, the bushing is completely immersed in the oil tank, so it is called oil-oil bushing.

[0003] When conducting conventional and high-voltage tests on transformers, it is necessary to install a test riser and a test bushing at the outlet of the oil-oil bushing. Installing the test riser and the test bushing requires hoisting the test riser and bushing, wiring, vacuuming, oil filling, and net discharge. After the test, the test equipment needs to be dismantled, which involves draining the oil, removing the bushing and the riser, and then vacuuming, oil filling, net discharge, and other processes are required before it can be put into operation. This seriously affects the progress of product commissioning. If the transformer needs to be tested next time, the above steps need to be repeated, which causes a lot of work and difficulties for later maintenance and testing, and also consumes a lot of manpower and material resources, which is not conducive to product commissioning and operation and maintenance. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a transformer outlet bushing device, a transformer and a use method in view of the above-mentioned deficiencies in the prior art. The transformer outlet device can conveniently perform high-voltage tests on the transformer and can be quickly put into operation after the test.

[0005] According to an embodiment of a first aspect of the present invention, there is provided a transformer outlet bushing device, comprising: a mounting seat, an oil-oil bushing, a cable terminal and a test terminal; a housing cavity is provided inside the mounting seat, the housing cavity comprises a first housing section and a second housing section, the first housing section extends along a first direction, the second housing section extends along a second direction, the first direction and the second direction are perpendicular to each other, one end of the first housing section is communicated with the middle part of the second housing section, and the other end is communicated with the inner cavity of the transformer box; the cable terminal and the test terminal are arranged opposite to each other, and are respectively installed on the side walls of the two end portions of the second housing section; the oil-oil bushing is installed in the first housing section of the housing cavity In the section, one end of the oil-oil casing is provided with a terminal, and the other end is electrically connected to the transformer winding, the terminal is located between the cable terminal and the test terminal; the test terminal is electrically connected to the terminal through a first current-carrying lead, the test terminal has a first state or a second state, when the test terminal is in the first state, it is used to apply a test voltage to the transformer to perform a high-voltage test on the transformer, when the test terminal is in the second state, the test terminal stops applying voltage to the transformer; the cable terminal is electrically connected to the terminal through a second current-carrying lead, and is used to input / output power to the transformer when the test terminal is in the second state.

[0006] Preferably, the test terminal includes a base, a plug and a plug-in sleeve; the base passes through and is installed on the side wall of one end of the second accommodating section, the base is connected to the terminal block via a first current-carrying lead, the plug-in sleeve is pluggable to the base, and when the plug-in sleeve is inserted into the base, the test terminal is in a first state, the plug-in sleeve is electrically connected to the terminal block via the first current-carrying lead, the plug-in sleeve is electrically connected to the transformer winding lead via the first current-carrying lead and the oil-oil sleeve, and the plug-in sleeve is used to apply a specified test voltage to the transformer to perform a high-voltage test on the transformer; the plug is pluggable to the base, and when the plug is inserted into the base, the test terminal is in a second state.

[0007] Preferably, the base is provided with a plug-in slot, and an electrical contact is provided at the bottom of the plug-in slot, and the electrical contact is connected to the wiring terminal through a first current-carrying lead. The shape of the plug is adapted to the plug-in slot, and the plug-in sleeve includes a plug and a sleeve body, and the plug is connected to the sleeve body. The shape of the plug is adapted to the plug-in slot, and when the plug is inserted into the plug-in slot, the plug is electrically connected to the electrical contact.

[0008] Preferably, the two end portions of the second accommodating section are respectively a first end and a second end, the cable terminal is connected to the side wall of the first end, the test terminal is connected to the side wall of the second end, and the first end is located above the second end.

[0009] According to an embodiment of the second aspect of the present invention, there is provided a transformer, comprising: a box, a coil and the above-mentioned transformer outlet bushing device; the coil is accommodated in the box, the mounting seat of the transformer outlet bushing device is connected to the box, and the first accommodating section of the transformer is communicated with the inner cavity of the box, the oil-oil bushing in the transformer outlet bushing device is electrically connected to the coil, and the test terminal of the transformer outlet bushing device is used to apply a test voltage to the transformer to perform a high-voltage test on the transformer; the cable terminal is used to input / output power to the transformer when the test terminal stops applying voltage to the coil.

[0010] According to an embodiment of the third aspect of the present invention, there is provided a method for using the above-mentioned transformer outlet bushing device, comprising the following steps:

[0011] Adjusting the test terminal of the transformer outlet bushing device to a first state to obtain a high-voltage test structure;

[0012] Through the high-voltage test structure, the transformer is subjected to a high-voltage test to determine whether the transformer meets the high-voltage performance requirements;

[0013] According to the judgment result, the transformer is repaired, or the test terminal of the transformer outlet bushing device is adjusted to the second state, so that the transformer can be put into operation.

[0014] Preferably, before the step of adjusting the test terminal of the transformer outlet bushing device to the first state to obtain the high-voltage test structure, the step further includes:

[0015] Performing a vacuum operation on the accommodating chamber of the transformer outlet bushing device;

[0016] Filling the accommodating cavity of the transformer outlet bushing device after evacuation with oil;

[0017] After the oil is filled, the containing cavity is completely vented.

[0018] Preferably, the test terminal of the transformer outlet bushing device used in the method comprises a base, a plug and a plug-in bushing. The base passes through and is installed on the side wall of one end of the second accommodating section, and the base is connected to the terminal through a first current-carrying lead. The plug-in bushing is pluggable and connected to the base. When the plug-in bushing is inserted into the base, the test terminal is in a first state, the plug-in bushing is electrically connected to the terminal through the first current-carrying lead, the plug-in bushing is electrically connected to the transformer winding lead through the first current-carrying lead and the oil-oil bushing, and the plug-in bushing is used to apply a test specified voltage to the transformer to perform a high voltage test on the transformer. The plug-in bushing is pluggable and connected to the base. When the plug is inserted into the base, the test terminal is in a second state.

[0019] The step of adjusting the test terminal of the transformer outlet bushing device to the first state to obtain a high-voltage test structure is specifically:

[0020] Inserting the plug-in sleeve of the test terminal of the transformer outlet bushing device into the base, so that the test terminal is in a first state;

[0021] The step of repairing the transformer according to the judgment result, or adjusting the test terminal of the transformer outlet bushing device to the second state so that the transformer can be put into operation, is specifically:

[0022] If it is determined that the transformer can meet the high voltage performance requirements, the plug of the test terminal of the transformer outlet bushing device is inserted into the base, so that the test terminal is in the second state, so that the transformer can be put into operation

[0023] If it is determined that the transformer cannot meet the high voltage performance requirements, the transformer needs to be repaired.

[0024] Preferably, the step of performing a high voltage test on the transformer according to the high voltage test structure to determine whether the transformer meets the high voltage performance requirements specifically includes:

[0025] gradually applying a test voltage to the transformer through a test terminal in the transformer outlet bushing device;

[0026] According to the preset voltage threshold, determine whether the test voltage value reaches the voltage threshold:

[0027] If not, continue to increase the test voltage;

[0028] If yes, stop increasing the test voltage, and maintain the test voltage of the transformer according to the preset voltage holding time, and monitor the state of the transformer to obtain the transformer state parameters after pressurization;

[0029] According to the transformer state parameters, it is determined whether the transformer meets the high voltage performance requirements.

[0030] Preferably, the transformer state parameter includes a transformer winding voltage value;

[0031] The step of judging whether the transformer meets the high voltage performance requirement according to the transformer state parameter specifically includes:

[0032] According to the transformer winding voltage value, determine whether the transformer winding fails:

[0033] If the transformer winding voltage value is less than or equal to a preset winding voltage threshold, it is determined that the transformer winding fails, that is, the transformer does not meet the high voltage performance requirements;

[0034] If the transformer voltage value is greater than a preset winding voltage threshold, it is determined that the transformer winding has not failed, that is, the transformer meets the high voltage performance requirements.

[0035] The two ends of the second accommodating chamber of the transformer outlet bushing device in the present invention are respectively installed with a test terminal and a cable terminal, and the transformer can be conveniently and quickly tested for high voltage through the test terminal. After the high voltage test is completed, the transformer can be put into operation directly through the cable terminal without the need to perform oil discharge, bushing removal, and seat elevation, and then multiple processes such as vacuuming, oil filling, and net discharge are required before it can be put into operation. Specifically, the test terminal in the device includes a base, a plug, and a plug-in bushing. When the plug-in bushing is inserted into the base, the test terminal is in a first state. In the first state, the external voltage device can apply a test voltage to the transformer winding through the plug-in bushing and the electrical contact of the base to perform a high voltage test on the transformer. When the high voltage test is completed, the plug is inserted into the base, and the test terminal is in a second state, that is, the test voltage is no longer applied to the winding. At this time, the power input / output of the transformer can be performed directly through the cable terminal. Therefore, the transformer outlet bushing device can conveniently perform a high voltage test on the transformer and can be quickly put into operation after the test is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a structural schematic diagram of a transformer outlet bushing device when a test terminal in some embodiments of the present invention is in a first state;

[0037] Figure 2 is a structural schematic diagram of a transformer outlet bushing device when the test terminal in some embodiments of the present invention is in a second state;

[0038] Figure 3 It is an existing high-voltage test structure for oil-oil bushing outlet transformer.

[0039] In the figure: 1-plug-in sleeve, 2-base, 3-mounting hand hole, 41-first current-carrying lead, 42-second current-carrying lead, 5-oil-oil sleeve, 6-cable terminal, 7-plug, 8-mounting flange. DETAILED DESCRIPTION

[0040] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0041] In the description of the present invention, it should be noted that the terms "upper", "lower" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience and simplification of the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0042] In the description of the present invention, the terms “first” and “second” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connect", "set", "install", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0044] Example 1

[0045] See also Figure 1 and Figure 2 The present invention discloses a transformer outlet bushing device, comprising: a mounting seat, an oil-oil bushing 5, a cable terminal 6 and a test terminal.

[0046] Among them, a accommodating cavity is provided inside the mounting seat, and the accommodating cavity includes a first accommodating section and a second accommodating section. The first accommodating section extends along a first direction, and the second accommodating section extends along a second direction. The first direction and the second direction are perpendicular to each other. One end of the first accommodating section is connected to the middle of the second accommodating section, and the other end is connected to the inner cavity of the transformer box. The cable terminal 6 and the test terminal are arranged opposite to each other, and are respectively installed on the side walls of the two end portions of the second accommodating section. The oil-oil casing 5 is installed in the first accommodating section of the accommodating cavity. One end of the oil-oil casing 5 is provided with a wiring terminal, and the other end is electrically connected to the transformer winding. The wiring terminal is located between the cable terminal 6 and the test terminal. The test terminal is electrically connected to the wiring terminal through the first current-carrying lead 41, and the test terminal has a first state or a second state. As Figure 1 As shown, when the test terminal is in the first state, it is used to apply a test voltage to the transformer to perform a high voltage test on the transformer; Figure 2 As shown, when the test terminal is in the second state, the test terminal stops applying voltage to the transformer. The cable terminal 6 is electrically connected to the connection terminal through the second current-carrying lead 42, and is used to input / output power to the transformer when the test terminal is in the second state.

[0047] It should be noted that a transformer is a device that uses the principle of electromagnetic induction to change AC voltage. It is mainly composed of the following parts: iron core, winding, oil tank and outlet bushing. Among them, the iron core is the magnetic circuit part of the transformer, which is made of hot-rolled or cold-rolled silicon steel sheets with a high silicon content to reduce eddy current and hysteresis losses. The iron core is divided into two parts: the core column and the cross piece, and the core column is covered with a winding. The winding is wound with double-wire insulated flat wire or enameled round wire. According to the connection relationship with the power supply and the load, the winding is divided into primary winding (primary winding) and secondary winding (secondary winding or secondary winding). The oil tank is used to hold transformer oil (i.e. insulating oil) and plays a role in insulation and heat dissipation. Outlet bushing: used to output the voltage of the transformer to the external circuit, so the outlet bushing is usually electrically connected to the winding lead in the transformer.

[0048] There are many forms of transformer outlet bushings, among which the oil-oil bushing 5 is a common outlet bushing form. The bushing is arranged horizontally in the elevated seat (i.e., the mounting seat in this embodiment), the elevated seat is connected to the oil tank, and the bushing is completely immersed in the oil, so the bushing is called the oil-oil bushing 5. The outlet of the transformer winding is realized by the oil-oil bushing 5, which has the following advantages: first, the oil-oil bushing 5 is immersed in the insulating oil, which utilizes the high insulation strength characteristics of the transformer oil. The transformer oil has a much higher insulation strength than air, which can effectively isolate electrical components, prevent current leakage and short circuit, thereby improving the overall insulation performance of the transformer. Secondly, the specific heat capacity of the transformer oil is relatively large, and it is a good coolant. The oil-oil bushing 5 is immersed in the oil, which can more effectively transfer the heat generated during the operation of the transformer to the radiator through the flow and convection of the oil, ensuring that the transformer maintains an appropriate temperature during operation and prevents overheating damage. Moreover, the oil-oil bushing 5 has a compact structure and occupies a small area. Therefore, the oil-oil casing 5 is widely used in indoor substations, offshore wind power and other projects.

[0049] It should also be noted that since the transformer is a vital device in the power system, its safe operation is directly related to the stability and reliability of the entire power system. Therefore, it is necessary to conduct high-voltage tests on the transformer regularly to detect the insulation and electrical properties of the transformer under high voltage to ensure that it can withstand the voltage and current shocks during normal operation and sudden failures.

[0050] However, if Figure 3 As shown, Figure 3 It is an existing high-voltage test structure for transformers with oil-oil bushing 5 outlets. As for the oil-oil bushing 5, since it is immersed in insulating oil, it is impossible to directly carry out high-voltage tests. When the transformer is subjected to conventional and high-voltage tests, it is necessary to install a test riser and a test bushing at the outlet of the oil-oil bushing 5. Moreover, if a cable terminal test is adopted, the cables connected to the transformer need to be removed for the test, and special test taps and test cables need to be installed; failure to remove them will interfere with the test. If a cable terminal is used to implement a high-voltage test, special cable terminal test plugs and test cables need to be installed. The cable terminal has high requirements for disassembly and installation. If the installation is not well controlled, it may cause damage to the equipment, and special personnel are required to guide the installation. The rental cost of special cable terminal test plugs and test cables is high.

[0051] The installation of a test riser and a test bushing requires multiple steps such as hoisting the test riser and bushing, wiring, vacuuming, oiling, and clearing. After the test, the test equipment needs to be dismantled, which involves draining the oil, removing the bushing and the riser, and then vacuuming, oiling, and clearing again before it can be put into operation. This seriously affects the progress of the product's commissioning. If the transformer needs to be tested next time, the above steps need to be repeated, which causes a lot of work and difficulties for subsequent maintenance and testing, and also consumes a lot of manpower and material resources, which is not conducive to product commissioning and operation and maintenance.

[0052] In this regard, a transformer outlet bushing device is proposed in this embodiment. The device aims at the above-mentioned problem that the oil-oil bushing 5 outlet transformer structure needs to be installed and disassembled many times before and after the high-voltage test, which is labor-intensive and time-consuming; and when the test is repeated later, the test equipment needs to be repeatedly installed and disassembled, which is tedious work. The device can conveniently perform high-voltage tests on transformers and can be quickly put into operation after the test is completed.

[0053] Specifically, the two ends of the second accommodating chamber of the transformer outlet bushing device are respectively installed with a test terminal and a cable terminal 6, and the transformer can be conveniently and quickly tested for high voltage through the test terminal. After the high voltage test is completed, the transformer can be put into operation directly through the cable terminal 6, without the need to perform oil discharge, bushing removal, and seat elevation, and then multiple processes such as vacuuming, oil filling, and net discharge are required before it can be put into operation. Specifically, the test terminal in the device includes a base 2, a plug 7, and a plug-in bushing 1. When the plug-in bushing 1 is inserted into the base 2, the test terminal is in a first state. In the first state, the external voltage device can apply a test voltage to the transformer winding through the electrical contacts of the plug-in bushing 1 and the base 2 to perform a high voltage test on the transformer. When the high voltage test is completed, the plug 7 is inserted into the base 2, and the test terminal is in a second state, that is, the test voltage is no longer applied to the winding. At this time, the power input / output of the transformer can be performed directly through the cable terminal 6. Therefore, the transformer outlet bushing device can conveniently perform a high voltage test on the transformer and can be quickly put into operation after the test is completed.

[0054] See also Figure 1 and Figure 2In this embodiment, the test terminal includes a base 2, a plug 7 and a plug sleeve 1. The base 2 penetrates and is installed on the side wall of one end of the second accommodating section. The base 2 is connected to the wiring terminal through the first current-carrying lead 41. The plug sleeve 1 is pluggable with the base 2. When the plug sleeve 1 is inserted into the base 2, the test terminal is in the first state. The plug sleeve 1 is electrically connected to the wiring terminal through the first current-carrying lead 41. The plug sleeve 1 is electrically connected to the transformer winding lead through the first current-carrying lead 41 and the oil-oil bushing 5. The plug sleeve 1 is used to apply the test specified voltage to the transformer to perform a high-voltage test on the transformer. The plug 7 is pluggable with the base 2. When the plug 7 is inserted into the base 2, the test terminal is in the second state.

[0055] like Figure 1 As shown, when a high-voltage test is required, first, the plug-in sleeve 1 of the test terminal of the transformer outlet bushing device is inserted into the base 2, so that the test terminal is in the first state. Then, the external voltage device can apply the test voltage to the transformer winding through the plug-in sleeve 1 and the power contact of the base 2 to perform a high-voltage test on the transformer. Specifically, the test voltage is gradually applied to the transformer through the test terminal in the transformer outlet bushing device. According to the preset voltage threshold, it is judged whether the test voltage value reaches the voltage threshold: if not, the test voltage continues to be increased; if so, the test voltage is stopped, and the test voltage of the transformer is maintained according to the preset voltage holding time, and the state of the transformer is monitored to obtain the transformer state parameters after pressurization. According to the transformer state parameters, it is judged whether the transformer meets the high-voltage performance requirements.

[0056] The above-mentioned preset voltage threshold (i.e., the specified test voltage) can refer to the provisions of the national standard "Power Transformer Inspection Regulations" (GB / T 6451-2015): For transformers with a rated voltage of 3kV and below, the withstand voltage test voltage is 2.5kV; for transformers with a rated voltage of more than 3kV, the withstand voltage test voltage is 3kV. During the test, the voltage display should be closely monitored to ensure that the voltage is stable within the specified range, and pay attention to whether the voltage drops suddenly. The preset voltage holding time is 1-5 minutes. In this embodiment, the voltage holding time is 1 minute.

[0057] Furthermore, the transformer state parameters mainly include the transformer winding voltage value. Of course, they may also include temperature, transformer noise, etc. Specifically, according to the transformer state parameters, it is judged whether the transformer meets the high-voltage performance requirements. The judgment criteria are: if the transformer winding voltage value is less than or equal to the preset winding voltage threshold, it is judged that the transformer winding fails, that is, the transformer does not meet the high-voltage performance requirements; if the transformer voltage value is greater than the preset winding voltage threshold, it is judged that the transformer winding does not fail, that is, the transformer meets the high-voltage performance requirements.

[0058] The above-mentioned winding voltage threshold is determined according to the actual situation, and the winding voltage threshold can be (0.2-0.5) times the test specified voltage. For example: when the withstand voltage test voltage (i.e., the test specified voltage) is 3kV, when the winding voltage threshold is selected as 0.2, 0.4 or 0.5 times the test specified voltage, the winding voltage thresholds are 0.6kV, 1.2kV, and 1.5kV, respectively. Exemplarily, taking 0.2 times the test specified voltage as an example, the voltage of the transformer winding is detected in real time by a voltage monitoring device. When the real-time voltage of the transformer winding (i.e., the above-mentioned transformer winding voltage value) is lower than 0.6kV, it is considered that the transformer winding is broken down, that is, the transformer winding fails, and the transformer cannot meet the high-voltage performance requirements. At this time, the transformer needs to be inspected and repaired. Specifically, it is mainly to replace new winding coils to meet the high-voltage performance requirements.

[0059] like Figure 2 As shown, after the transformer completes the high-voltage test (meets the high-voltage performance requirements, or completes the inspection and maintenance), the plug 7 of the test terminal of the transformer outlet bushing device is inserted into the base 2, and the test terminal is in the second state, so that the transformer can be put into operation.

[0060] like Figure 1 As shown, the plug-in bushing 1 is connected to the base 2 to form a transformer test lead bushing. The base 2 of the plug-in bushing 1 is connected to the oil-oil bushing 5 through a current-carrying lead (a first current-carrying lead 41). A mounting hand hole 3 is also provided on the mounting seat (i.e., the elevated seat). The mounting hand hole 3 allows the operator to connect the base 2 of the plug-in bushing 1 with the first current-carrying lead 41, and connect the oil-oil bushing 5 (connection terminal) with the current-carrying lead, and then connect the plug-in cable terminal 6 with the second current-carrying lead 42. The oil-oil bushing 5 is installed in the first accommodating section of the accommodating cavity through the mounting flange 8.

[0061] In other words, one end of the first current-carrying lead 41 is connected to the base 2 of the plug-in bushing 1, and the other end is connected to the oil-oil bushing 5 (wiring terminal). One end of the second current-carrying lead 42 is connected to the oil-oil bushing 5 (wiring terminal), and the other end is connected to the plug-in cable terminal 6 to achieve current connection. The second current-carrying lead 42 connects the transformer body with the external system through the oil-oil bushing 5 to achieve power input. The plug-in cable terminal 6 is connected to the external electrical equipment through a cable to achieve external power input busbar system.

[0062] like Figure 2 As shown, after the test is completed, it is only necessary to pull out the plug sleeve 1 and put the plug 7 into the base 2, and the transformer can be put into operation.

[0063] In some other embodiments, the switching between the first state and the second state of the test terminal can also be achieved by other means, for example: after the test is completed, after the oil is drained, the two ends of the first current-carrying lead are removed through the hand hole reserved in the test riser, the entire test sleeve and the test riser are removed, and the oil is cleaned and filled, etc., and then the test terminal can be switched to the second state.

[0064] Please continue reading Figure 1 and Figure 2 In this embodiment, the base 2 is provided with a plug slot, and an electrical contact is provided at the bottom of the plug slot. The electrical contact is connected to the terminal through the first current-carrying lead 41, and the shape of the plug 7 is adapted to the plug slot. The plug sleeve 1 includes a plug and a sleeve body, the plug is connected to the sleeve body, the shape of the plug is adapted to the plug slot, and when the plug is inserted into the plug slot, the plug is electrically connected to the electrical contact.

[0065] Specifically, the shape of the plug slot is an inverted cone, and the shapes of the plug and plug 7 of the plug sleeve 1 are also inverted cones. Such a shape design can facilitate the staff to replace the plug sleeve 1 and the plug 7.

[0066] It should also be noted that the accommodating chamber is filled with insulating oil. In order to facilitate the replacement of the plug 7 or the plug-in sleeve 1 and avoid leakage of the insulating oil, the test terminal is arranged above the cable terminal 6. Specifically, the two end portions of the second accommodating section are respectively the first end and the second end, the cable terminal 6 is connected to the side wall of the first end, the test terminal is connected to the side wall of the second end, and the first end is located above the second end. The first end is located above the second end, which can avoid leakage of insulating oil when replacing the plug 7 or plugging the sleeve 1.

[0067] In this embodiment, the oil-oil casing, the first current-carrying lead, the second current-carrying lead, the plug-in casing of the test terminal, and the cable terminal (including the cable and the cable connector) can all be commercially available equipment.

[0068] In summary, the technical solution adopted by the transformer outlet bushing device in this embodiment is: the test bushing is a pluggable bushing, which is first connected to the bushing plug-in base 2 through the oil-oil bushing 5 before the test, and then vacuumed, oiled, and completely discharged. When the test is required, the plug-in bushing 1 is inserted into the base 2, and the test can be directly performed (by pressurizing to the specified test voltage). The purpose of the high-voltage test is to verify the main performance of the transformer and test the transformer's withstand voltage. After the test is completed, only the plug-in bushing 1 needs to be pulled out, the plug 7 is placed in the base 2, and the transformer can be put into operation; when the second test is performed, the plug 7 is removed, and the plug-in bushing 1 is inserted into the test base 2 for another test.

[0069] The transformer outlet bushing device has a simple structure and is easy to install. It solves the problem of difficult testing of oil-oil bushing 5 outlet transformers, that is, each high-voltage test requires a large workload, and each test requires installation and removal of test equipment, oil filling, oil draining, and clean draining, etc., especially when the test is needed again in the later period, there is no need to install and remove the test equipment as before. The new structure only needs to pull out the plug bushing 1 after the test is completed, and put the plug 7 into the base 2, and the transformer can be put into operation; when the second test is performed, the plug 7 is removed, and the plug bushing 1 is inserted into the test base 2 for another test, which greatly shortens the test cycle and reduces the workload of the test.

[0070] Example 2

[0071] See also Figure 1 The present invention also discloses a transformer, comprising: a box, a coil and the transformer outlet bushing device in embodiment 1.

[0072] The coil is accommodated in the box, the mounting seat of the transformer outlet bushing device is connected to the box, and the first accommodating section of the transformer is connected to the inner cavity of the box, the oil-oil bushing 5 in the transformer outlet bushing device is electrically connected to the coil, and the test terminal of the transformer outlet bushing device is used to apply a test voltage to the transformer to perform a high-voltage test on the transformer. The cable terminal 6 is used to input / output power to the transformer when the test terminal stops applying voltage to the coil.

[0073] It should be noted that the transformer box is filled with insulating oil to achieve insulation and heat dissipation functions. The transformer in this embodiment can conveniently perform high voltage tests on the transformer by adopting the transformer outlet bushing device in Example 1, and can be quickly put into operation after the test.

[0074] Specifically, when conducting high-voltage tests, there is no need to install and dismantle the test equipment before each test, nor is there any need to repeat the tedious work of filling, draining, and draining before each test. The new structure only needs to pull out the plug sleeve 1 after the test is completed, and put the plug 7 into the base 2, and the transformer can be put into operation; when the second test is conducted, the plug 7 is taken out, and the plug sleeve 1 is inserted into the test base 2 for another test, which greatly shortens the test cycle and reduces the workload of the test.

[0075] Therefore, the transformer can quickly realize high voltage testing and be put into operation quickly.

[0076] Example 3

[0077] The present invention also discloses a method for using the transformer outlet bushing device in embodiment 1, the method comprising the following steps:

[0078] The test terminal of the transformer outlet bushing device is adjusted to the first state to obtain a high-voltage test structure (the high-voltage test structure is the transformer outlet bushing device with the test terminal in the first state, at which time the transformer outlet bushing is connected to the transformer).

[0079] The transformer is subjected to a high voltage test through the high voltage test structure to determine whether the transformer meets the high voltage performance requirements.

[0080] According to the judgment result, the transformer is repaired, or the test terminal of the transformer outlet bushing device is adjusted to the second state, so that the transformer can be put into operation.

[0081] It should be noted that if Figure 1 As shown, the plug-in bushing 1 is connected to the base 2 to form a transformer test outlet bushing. The base 2 of the plug-in bushing 1 is connected to the oil-oil bushing 5 through a current-carrying lead (first current-carrying lead 41). A mounting hand hole 3 is also provided on the mounting seat (i.e., the elevated seat). The mounting hand hole 3 allows the operator to connect the base 2 of the plug-in bushing 1 with the first current-carrying lead 41, and connect the oil-oil bushing 5 (wiring terminal) with the current-carrying lead, and then connect the plug-in cable terminal 6 with the second current-carrying lead 42. In other words, one end of the first current-carrying lead 41 is connected to the base 2 of the plug-in bushing 1, and the other end is connected to the oil-oil bushing 5 (wiring terminal). One end of the second current-carrying lead 42 is connected to the oil-oil bushing 5 (wiring terminal), and the other end is connected to the plug-in cable terminal 6 to realize the connection of current. The transformer body is connected to the external system through the oil-oil bushing 5 to realize the input of electric energy. The plug-in cable terminal 6 is connected to the external electrical equipment through a cable to realize the external power input bus system.

[0082] like Figure 2 As shown, after the test is completed, it is only necessary to pull out the plug sleeve 1 and put the plug 7 into the base 2, and the transformer can be put into operation.

[0083] Specifically, before the step of adjusting the test terminal of the transformer outlet bushing device to the first state to obtain the high-voltage test structure, the step further includes:

[0084] Performing a vacuum operation on the accommodating chamber of the transformer outlet bushing device;

[0085] Performing oil filling operation on the accommodating cavity of the transformer outlet bushing device after vacuuming;

[0086] After the oil is filled, the containing cavity is completely vented.

[0087] In this embodiment, vacuuming can be achieved by a vacuuming device, such as a vacuum pump. The vacuum pump is connected to the containing chamber through a pipeline to form a complete vacuum system. Start the vacuum pump and start the vacuuming process. Exemplarily, the vacuum degree is evenly increased to 1.3Kpa within one hour, and this vacuum degree is maintained for 30 minutes. Continue to vacuum to ≤50Pa (read by the vacuum gauge installed on the top of the transformer), and maintain this vacuum degree for a period of time (usually more than 6 hours) to ensure that the gas inside the transformer is fully extracted.

[0088] The existing oil filling system can be used to fill the accommodating chamber with oil. The oil filling system is connected to the accommodating chamber. The oil filling system includes a vacuum oil filter and an oil storage tank. First, the staff connects the vacuum oil filter, the oil storage tank and the transformer to prepare for oil filling. Then, the staff opens the oil drain valve of the oil storage tank and the oil filling valve of the transformer, starts oil filling, turns on the vacuum oil filter, and properly controls the valve to slowly inject the qualified oil in the oil storage tank into the transformer from the bottom of the transformer at a rate of 4-6 tons per hour. During this process, the oil level is closely monitored, and the oil filling is stopped when the oil level is 100-150mm away from the top of the box. Close the oil filling valve on the transformer, remove the oil pipe and seal its pipe mouth with a blanking plate.

[0089] When performing the net exhaust operation, first let the transformer stand for a period of time (the specific time depends on the transformer model and test requirements) so that the internal oil can flow fully and reach a balanced state. During the standing process, the residual gas inside the transformer will gradually dissolve in the oil or be discharged through the oil pillow and other components. During or after the standing process, check whether there is gas accumulation in the gas relay. If there is, it means that there is still gas inside the transformer that has not been completely discharged, and the exhaust operation needs to be continued. If gas is found to be accumulated in the gas relay or there is still gas inside the transformer that has not been discharged, the exhaust operation can be performed through the exhaust valve. When exhausting, the exhaust valve should be opened slowly to avoid oil spraying. After the exhaust operation is completed, check the oil level of the transformer, the gas relay and the sealing parts again for leakage. Only after ensuring that everything is normal can subsequent tests or commissioning operations be carried out.

[0090] In this embodiment, the test terminal of the transformer outlet bushing device used in this method includes a base 2, a plug 7 and a plug-in bushing 1. The base 2 penetrates and is installed on the side wall of one end of the second accommodating section, and the base 2 is connected to the terminal through a first current-carrying lead 41. The plug-in bushing 1 is pluggable and connected to the base 2. When the plug-in bushing 1 is inserted into the base 2, the test terminal is in a first state, the plug-in bushing 1 is electrically connected to the terminal through the first current-carrying lead 41, and the plug-in bushing 1 is electrically connected to the transformer winding lead through the first current-carrying lead 41 and the oil-oil bushing 5. The plug-in bushing 1 is used to apply the test specified voltage to the transformer to perform a high-voltage test on the transformer. The plug 7 is pluggable and connected to the base 2. When the plug 7 is inserted into the base 2, the test terminal is in a second state.

[0091] The above-mentioned step of adjusting the test terminal of the transformer outlet bushing device to the first state to obtain the high-voltage test structure is specifically as follows:

[0092] The plug-in sleeve 1 of the test terminal of the transformer outlet bushing device is inserted into the base 2, so that the test terminal is in the first state. By using the base 2, the plug 7 and the plug-in sleeve 1, the state of the test terminal can be quickly switched.

[0093] According to the judgment result, the transformer is repaired, or the test terminal of the transformer outlet bushing device is adjusted to the second state so that the transformer can be put into operation, specifically, the steps are:

[0094] If it is determined that the transformer can meet the high voltage performance requirements, the plug 7 of the test terminal of the transformer outlet bushing device is inserted into the base 2, so that the test terminal is in the second state, so that the transformer can be put into operation;

[0095] If it is determined that the transformer cannot meet the high voltage performance requirements, the transformer needs to be repaired. Specifically, it mainly replaces new winding coils to meet the high voltage performance requirements.

[0096] In this embodiment, the above-mentioned step of performing a high voltage test on the transformer according to the high voltage test structure to determine whether the transformer meets the high voltage performance requirements specifically includes:

[0097] Gradually apply the test voltage to the transformer through the test terminal in the transformer outlet bushing device;

[0098] According to the preset voltage threshold, determine whether the test voltage value reaches the voltage threshold:

[0099] If not, continue to increase the test voltage;

[0100] If yes, stop increasing the test voltage, and maintain the test voltage of the transformer according to the preset voltage holding time, and monitor the state of the transformer to obtain the transformer state parameters after pressurization;

[0101] Based on the transformer status parameters, determine whether the transformer meets the high voltage performance requirements.

[0102] The above-mentioned preset voltage threshold (i.e., the specified test voltage) can refer to the provisions of the national standard "Power Transformer Inspection Regulations" (GB / T 6451-2015): For transformers with a rated voltage of 3kV and below, the withstand voltage test voltage is 2.5kV; for transformers with a rated voltage of more than 3kV, the withstand voltage test voltage is 3kV. During the test, the voltage display should be closely monitored to ensure that the voltage is stable within the specified range, and pay attention to whether the voltage drops suddenly. The preset voltage holding time is 1-5 minutes. In this embodiment, the voltage holding time is 1 minute.

[0103] Furthermore, the transformer state parameters mainly include transformer winding voltage values, and of course, may also include temperature, transformer noise, and the like.

[0104] The above-mentioned method of judging whether the transformer meets the high voltage performance requirements based on the transformer status parameters specifically includes:

[0105] According to the transformer winding voltage value, determine whether the transformer winding fails:

[0106] If the transformer winding voltage value is less than or equal to the preset winding voltage threshold, the transformer winding is determined to be failed, that is, the transformer does not meet the high voltage performance requirements;

[0107] If the transformer voltage value is greater than the preset winding voltage threshold, it is determined that the transformer winding has not failed, that is, the transformer meets the high voltage performance requirements.

[0108] The above-mentioned winding voltage threshold is determined according to the actual situation, and the winding voltage threshold can be (0.2-0.5) times the test specified voltage. For example: when the withstand voltage test voltage (i.e., the test specified voltage) is 3kV, when the winding voltage threshold is selected as 0.2, 0.4 or 0.5 times the test specified voltage, the winding voltage thresholds are 0.6kV, 1.2kV, and 1.5kV, respectively. Exemplarily, taking 0.2 times the test specified voltage as an example, the voltage of the transformer winding is detected in real time by a voltage monitoring device. When the real-time voltage of the transformer winding (i.e., the above-mentioned transformer winding voltage value) is lower than 0.6kV, it is considered that the transformer winding is broken down, that is, the transformer winding fails, and the transformer cannot meet the high-voltage performance requirements. At this time, the transformer needs to be inspected and repaired.

[0109] In other words, the high voltage test of the transformer usually includes the AC withstand voltage test, also known as the electrical strength test or dielectric strength test, which is an important test item to check whether the insulation structure of the transformer can work for a long time in actual operation without insulation breakdown accidents. The following are the basic steps of the transformer withstand voltage performance test:

[0110] Pre-boost: Before formally boosting (applying voltage), a pre-boost operation should be performed to check whether the test circuit is intact and observe whether the tested transformer has any abnormal sound or discharge.

[0111] Formal voltage boost: Start boosting from zero, and the boost speed should be uniform to avoid impact closing. When the voltage reaches the specified test voltage, start timing and keep the test voltage stable. During the test, the high-voltage circuit and instrument indication should be closely monitored to monitor whether the transformer under test has any abnormal sound.

[0112] Withstand voltage time: Maintain the specified test voltage for a certain period of time (usually 1 minute), during which no continuous arcing or breakdown is allowed to occur.

[0113] Voltage reduction and power off: After the withstand voltage time is over, quickly and evenly reduce the voltage to zero, and then cut off the power supply. Note that sudden power off should not be used to avoid the transformer breakdown caused by the oscillation overvoltage caused by the instantaneous voltage loss.

[0114] After the test, the device needs to be fully discharged to ensure that there is no residual charge.

[0115] Qualification judgment: If the voltmeter indication is stable during the test and there is no discharge sound or other abnormal phenomenon in the tested transformer, the test is considered to have passed.

[0116] Failure judgment: If the voltage meter indication drops sharply during the test, the transformer under test makes a discharge sound or other abnormal phenomena, the test is considered unqualified. At this time, the insulation structure of the transformer under test should be further checked to find out the cause of the fault and deal with it.

[0117] It should be noted that due to the differences between different types of transformers and test equipment, the specific test procedures and equipment manuals should be referred to in actual operation. At the same time, the withstand voltage test is a destructive test with high test voltage, and the operating procedures and safety regulations must be strictly followed to ensure the safety of test personnel and equipment.

[0118] The method for using the transformer outlet bushing device in this embodiment can quickly implement the high-voltage test of the transformer by adopting the transformer outlet bushing device in Example 1, and can quickly switch to the operating state of the transformer after the high-voltage test is completed to put the transformer into operation.

[0119] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A transformer outlet bushing device, characterized in that: include: Mounting seat, oil-oil casing (5), cable terminal (6) and test terminal; The mounting seat is provided with a containing cavity inside, and the containing cavity includes a first containing section and a second containing section, the first containing section extends along a first direction, the second containing section extends along a second direction, the first direction and the second direction are perpendicular to each other, one end of the first containing section is connected to the middle part of the second containing section, and the other end is connected to the inner cavity of the transformer box; The cable terminal (6) and the test terminal are arranged opposite to each other and are respectively installed on the side walls at both ends of the second accommodating section; The oil-oil casing (5) is installed in the first accommodating section of the accommodating cavity, one end of the oil-oil casing (5) is provided with a wiring terminal, and the other end is electrically connected to the transformer winding, and the wiring terminal is located between the cable terminal (6) and the test terminal; The test terminal is electrically connected to the connection terminal via a first current-carrying lead (41), and the test terminal has a first state or a second state. When the test terminal is in the first state, it is used to apply a test voltage to the transformer to perform a high-voltage test on the transformer. When the test terminal is in the second state, the test terminal stops applying voltage to the transformer. The cable terminal (6) is electrically connected to the connection terminal via a second current-carrying lead (42) and is used to input / output power to / from the transformer when the test terminal is in a second state.

2. The transformer outlet bushing device according to claim 1, characterized in that: The test terminal comprises a base (2), a plug (8) and a plug-in sleeve (1); The base (2) penetrates through and is installed on a side wall of one end of the second accommodating section, and the base (2) is connected to the connection terminal via a first current-carrying lead (41). The pluggable sleeve (1) is pluggably connected to the base (2); when the pluggable sleeve (1) is inserted into the base (2), the test terminal is in a first state; the pluggable sleeve (1) is electrically connected to the wiring terminal via a first current-carrying lead (41); the pluggable sleeve (1) is electrically connected to a transformer winding lead via the first current-carrying lead (41) and an oil-oil sleeve (5); the pluggable sleeve (1) is used to apply a test voltage to the transformer so as to perform a high-voltage test on the transformer; The plug (8) is pluggably connected to the base (2); when the plug (8) is inserted into the base (2), the test terminal is in a second state.

3. The transformer outlet bushing device according to claim 2, characterized in that: The base (2) is provided with a plug slot, the bottom of the plug slot is provided with an electrical contact, the electrical contact is connected to the connection terminal via a first current-carrying lead (41), the shape of the plug (8) is adapted to the plug slot, The plug-in sleeve (1) comprises a plug and a sleeve body, wherein the plug is connected to the sleeve body, the shape of the plug is adapted to the plug slot, and when the plug is inserted into the plug slot, the plug is electrically connected to the electrical contact.

4. The transformer outlet bushing device according to any one of claims 1 to 3, characterized in that: The two end portions of the second accommodating section are respectively a first end and a second end, the cable terminal (6) is connected to the side wall of the first end, the test terminal is connected to the side wall of the second end, and the first end is located above the second end.

5. A transformer, characterized in that: include: A box, a coil and a transformer outlet bushing device as claimed in any one of claims 1 to 4; The coil is contained in the box. The mounting seat of the transformer outlet bushing device is connected to the box, and the first accommodating section of the transformer is connected to the inner cavity of the box. The oil-oil bushing (5) in the transformer outlet bushing device is electrically connected to the coil. The test terminal of the transformer outlet bushing device is used to apply a test voltage to the transformer to perform a high voltage test on the transformer; the cable terminal (6) is used to input / output power to the transformer when the test terminal stops applying voltage to the coil.

6. A method for using the transformer outlet bushing device according to any one of claims 1 to 4, characterized in that: The steps include: Adjusting the test terminal of the transformer outlet bushing device to a first state to obtain a high-voltage test structure; Through the high-voltage test structure, the transformer is subjected to a high-voltage test to determine whether the transformer meets the high-voltage performance requirements; According to the judgment result, the transformer is repaired, or the test terminal of the transformer outlet bushing device is adjusted to the second state, so that the transformer can be put into operation.

7. The method according to claim 6, characterized in that Before the step of adjusting the test terminal of the transformer outlet bushing device to the first state to obtain the high voltage test structure, the step further includes: Performing a vacuum operation on the accommodating chamber of the transformer outlet bushing device; Filling the accommodating cavity of the transformer outlet bushing device after evacuation with oil; After the oil is filled, the containing cavity is completely vented.

8. The method according to claim 6 or 7, characterized in that: The method uses the transformer outlet bushing device according to claim 2 or 3, The step of adjusting the test terminal of the transformer outlet bushing device to the first state to obtain a high-voltage test structure is specifically: Inserting the plug-in bushing (1) of the test terminal of the transformer outlet bushing device into the base (2), so that the test terminal is in a first state; The step of repairing the transformer according to the judgment result, or adjusting the test terminal of the transformer outlet bushing device to the second state so that the transformer can be put into operation, is specifically: If it is determined that the transformer can meet the high voltage performance requirements, a plug (8) of the test terminal of the transformer outlet bushing device is inserted into the base (2) so that the test terminal is in a second state and the transformer can be put into operation; If it is determined that the transformer cannot meet the high voltage performance requirements, the transformer needs to be repaired.

9. The method according to claim 6, characterized in that The step of performing a high voltage test on the transformer according to the high voltage test structure to determine whether the transformer meets the high voltage performance requirements specifically includes: gradually applying a test voltage to the transformer through a test terminal in the transformer outlet bushing device; According to the preset voltage threshold, determine whether the test voltage value reaches the voltage threshold: If not, continue to increase the test voltage; If yes, stop increasing the test voltage, and maintain the test voltage of the transformer according to the preset voltage holding time, and monitor the state of the transformer to obtain the transformer state parameters after pressurization; According to the transformer state parameters, it is determined whether the transformer meets the high voltage performance requirements.

10. The method according to claim 9, characterized in that The transformer state parameter includes the transformer winding voltage value; The determining, based on the transformer state parameter, whether the transformer meets the high voltage performance requirement specifically includes: According to the transformer winding voltage value, determine whether the transformer winding fails: If the transformer winding voltage value is less than or equal to a preset winding voltage threshold, it is determined that the transformer winding fails, that is, the transformer does not meet the high voltage performance requirements; If the transformer voltage value is greater than a preset winding voltage threshold, it is determined that the transformer winding has not failed, that is, the transformer meets the high voltage performance requirements.

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