Series-parallel tapping method and device for reducing idle rate of tap turns of distribution transformer

Abstract

The present invention discloses a series-parallel tapping method and device for reducing the idle rate of the tap turns of a distribution transformer, belonging to the field of transformers. The series-parallel tapping method of the present invention connects the first tap winding and the second tap winding through a series-parallel tapping switch or a shorting piece that can change the number of running turns of the high-voltage winding, and in at least one intermediate tapping gear state, the idle tap turns are connected in parallel to participate in the operation, thereby reducing the operating loss of the distribution transformer in the intermediate gear (especially the rated gear), and can reduce the copper usage of the coil winding while ensuring the rated gear loss index, reduce the material cost of the distribution transformer, improve the filling rate of the transformer winding and the economy of the transformer, so that the operating loss and economy of the distribution transformer can be well taken into account; and the series-parallel tapping switch can be used on an oil-immersed transformer, and the shorting piece can be used on a dry transformer, and the application range is wide.

Description

Technical Field

[0001] The present invention relates to a distribution transformer tapping method and device, and more particularly to a series-parallel tapping method and device for reducing the idle rate of tap turns of a distribution transformer. Background Art

[0002] The high-voltage winding tapping of the distribution transformer is used to adjust the output voltage to meet the difference in grid line voltage. It changes the primary-secondary turns ratio by changing the number of running turns on one side, and ultimately changes the output voltage on the secondary side.

[0003] The current distribution transformers generally have three-speed and five-speed tapping positions. The tapping positions of the three-speed voltage regulating distribution transformer are as follows: Figure 1 As shown in the figure (only one phase winding is shown in the figure), the tapping position of the five-speed voltage regulating distribution transformer is as follows Figure 2 As shown (only one phase winding is shown in the figure). Figure 2 Taking the tapping position of the five-speed voltage-regulating distribution transformer shown as an example, its high-voltage winding is divided into a first tapping winding and a second tapping winding. The first tapping winding and the second tapping winding respectively have two sections of tapping turns connected in series, and each section of tapping turns has a tapping tap. The three tapping taps of the first tapping winding are represented by "2", "4", and "6", respectively, and the three tapping taps of the second tapping winding are represented by "3", "5", and "7", respectively. In the 1st gear position, the 2# tapping tap is connected to the 3# tapping tap. At this time, all the tapping turns are involved in the operation, and the number of running turns of the high-voltage winding is the largest; in the 2nd gear position, the 4# tapping tap is connected to the 3# tapping tap. At this time, the wire turns between the 2# tapping tap and the 4# tapping tap are idle; in the 3rd gear position, the 4# tapping tap is connected to the 5# tapping tap. At this time, the wire turns between the 2# tapping tap and the 4# tapping tap, and the wire turns between the 3# tapping tap and the 5# tapping tap are idle. The turns between the 2# and 6# taps are idle; in the 4th position, the 6# tap tap is connected to the 5# tap tap, at which time the turns between the 2# tap tap and the 6# tap tap, and the turns between the 3# tap tap and the 5# tap tap are idle; in the 5th position, the 6# tap tap is connected to the 7# tap tap, at which time the turns between the 2# tap tap and the 6# tap tap, and the turns between the 3# tap tap and the 7# tap tap are idle, and the number of running turns of the high-voltage winding is the least. It can be seen from the above tap position diagram that no matter it is a three-speed or five-speed voltage regulating distribution transformer, except that all tap turns are involved in operation in the 1st gear, there are some idle tap turns in the other gears, so that these idle tap turns cannot be fully utilized; and the rated gear of the three-speed transformer is generally the 2nd gear, and the rated gear of the five-speed transformer is generally the 3rd gear. The transformer is in the rated gear operation most of the time, and some tap turns will be idle for a long time.

[0004] The scheme of improving the utilization rate of transformer windings by series-parallel connection has been disclosed in the prior art, such as "a single-body transformer" disclosed in Chinese Patent No. 201210051532.9, "a new type of multi-voltage combination transformer" disclosed in Chinese Patent No. 201220091545.4, "a dry-type dual-voltage transformer" disclosed in Chinese Patent No. 201720399921.9, and "a dual-high-voltage conversion transformer" disclosed in Chinese Patent No. 202120143568.4, etc. These transformers all solve the problem of transformer dual voltage regulation, and all adopt two-speed voltage regulation, and realize the series or parallel connection of two sets of coils through series-parallel switches. The two-speed voltage regulation range is large, such as regulation between 6kV and 10kV. In fact, the above patent application is not the tap-shift adjustment of the multi-speed voltage-regulating distribution transformer mentioned above. Its tap-shift adjustment is controlled by a tap switch, that is, it has two parts: series-parallel adjustment and tap-shift adjustment, and requires two operating mechanisms, which increases the complexity of the transformer's adjustment. For multi-speed voltage-regulating distribution transformers, the purpose of tap voltage regulation is to adjust the output voltage above and below the rated voltage. The voltage regulation range of each gear is 2.5% to 5%, and there are a large number of voltage regulation gears. The most common ones are three and five gears, which are voltage fine-tuning to adapt to the difference in power grid line voltage. Although the proportion of tap turns in each gear of the distribution transformer is small, the problem of high idle rate of tap turns is also worthy of attention. In addition, due to the large number of tap voltage regulation gears, it is more difficult to improve the utilization rate of tap turns by series and parallel connection. The above patent applications all ignore or do not involve the problem of idle tap turns of multi-speed voltage-regulating distribution transformers. Therefore, how to make full use of idle tap turns is also of great significance to reducing the operating loss and manufacturing cost of multi-speed distribution transformers.

[0005] In addition, for oil-immersed transformers, the transformer coil windings are inside the oil tank, and the tapping turn adjustment is achieved through the tap changer. Figure 3 Taking the strip tap changer of the five-speed voltage-regulating distribution transformer shown as an example, it is composed of an operating mechanism 1 and a strip switch assembly 2. The strip switch assembly 2 includes a static contact bracket 2-1, a static contact 2-2, a moving contact bracket 2-3, a moving contact 2-4, a rack 2-5 and a gear 2-6. The static contact 2-2 is installed on the static contact bracket 2-1, and the moving contact 2-4 is installed on the moving contact bracket 2-3. The moving contact 2-4 slides and switches with the corresponding static contact 2-2. The rack 2-5 is fixed on the moving contact bracket 2-3. The operating mechanism 1 is provided with a gear 2-6, which meshes with the rack 2-5. The moving and static contact parts are located inside the oil tank 3. Each tap tap is connected to the corresponding static contact 2-2. During operation, the gear 2-6 is driven to rotate by the operating mechanism 1, and the moving contact bracket 2-3 is driven to slide relative to the static contact bracket 2-1 by the rack 2-5, thereby realizing the gear switching between the moving and static contacts. Figure 4The relationship between the gear position and voltage corresponding to the tap changer of the five-gear transformer is shown. As for the oil-immersed transformer, how to use the tap changer to fully utilize the idle tap turns of the transformer is also a difficulty faced by this field. Summary of the invention

[0006] 1. Technical problem to be solved by the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the existing distribution transformer, such as low utilization rate of tap turns and great difficulty in realizing series-parallel connection of multi-speed tap turns, and to provide a series-parallel tapping method and device for reducing the idle rate of tap turns of distribution transformers. The technical scheme of the present invention is adopted, for the high-voltage winding tapping of multi-speed voltage-regulating distribution transformers, a series-parallel tapping switch or a shorting piece is used to realize the parallel operation of idle tap turns of the distribution transformer, thereby reducing the operating loss of the distribution transformer in the middle gear (especially the rated gear), and reducing the copper usage of the winding while ensuring the rated gear loss index, thereby reducing the material cost of the distribution transformer, improving the filling rate of the transformer winding and the economy of the transformer, so that the operating loss and economy of the distribution transformer can be well taken into account, and the distribution transformer can be applied to oil-immersed distribution transformers and dry-type distribution transformers. In addition, for oil-immersed distribution transformers, the parallel operation of idle tap turns of the distribution transformer is realized through a series-parallel tap changer with two sets of moving and static contact switching mechanisms, making the multi-speed voltage regulation operation of the oil-immersed distribution transformer simple and convenient; for dry-type distribution transformers, the parallel operation of idle tap turns of the distribution transformer is realized through two short-circuit pieces, and by changing the connection position of the tap terminal of the tap panel with each tap tap and / or adding a transition terminal connected to the corresponding tap tap, the series or parallel connection of the tap turns is completed through short-circuit pieces of the same specification, making the tap operation of the dry-type distribution transformer simpler and more convenient.

[0008] 2. Technical solution

[0009] In order to achieve the above object, the technical solution provided by the present invention is:

[0010] The present invention discloses a series-parallel tapping method for reducing the idle rate of tap turns of a distribution transformer. The high-voltage winding of the distribution transformer comprises a first tap winding and a second tap winding. The first tap winding is formed by M tap turns connected in series, and the second tap winding is formed by N tap turns connected in series. M and N are both positive integers ≥ 1, and |MN|=0 or 1. Each tap turn of the first tap winding and the second tap winding has a tap tap. The first tap winding and / or the second tap winding also include a common turn connected in series with the corresponding tap turns. The first tap winding and the second tap winding are connected by a series-parallel tap switch or a shorting piece capable of changing the number of running turns of the high-voltage winding. When the distribution transformer is in at least one intermediate gear state, the first tap winding and the second tap winding have tap turns connected in parallel by the series-parallel tap switch or two shorting pieces, and the total number of turns of the tap turns connected in parallel in the first tap winding and the second tap winding is equal.

[0011] Furthermore, for the oil-immersed distribution transformer, the tap turns of the first tap winding and the second tap winding are connected through a series-parallel tap changer, and the series-parallel tap changer is designed with two sets of moving and static contact switching mechanisms connected to the tap taps of the corresponding tap turns. When the series-parallel tap changer is in an intermediate position, there is at least one intermediate position state, and the tap turns in the first tap winding and the second tap winding are connected in parallel through the mutual connection of the static contacts in the two sets of moving and static contact switching mechanisms.

[0012] Furthermore, in the series-parallel tap changer, the two sets of moving and static contact switching mechanisms are controlled by synchronous linkage.

[0013] Furthermore, the oil-immersed distribution transformer is a three-speed voltage regulating transformer, the first tap winding and the second tap winding both have a section of tap turns, and the series-parallel tap switch has three voltage regulating gears; when the series-parallel tap switch is in the first gear position, all common turns and tap turns in the first tap winding and the second tap winding operate in series; when the series-parallel tap switch is in the second gear position, the tap turns in the first tap winding and the second tap winding are connected in parallel and operate in series with the common turns; when the series-parallel tap switch is in the third gear position, only the common turns in the first tap winding and the second tap winding operate in series.

[0014] Furthermore, the two tap taps of the tap turns in the first tap winding are represented by 2# and 4# respectively according to the number of series turns from most to least, and the two tap taps of the tap turns in the second tap winding are represented by 3# and 5# respectively according to the number of series turns from most to least; the first group of moving and static contact switching mechanisms of the series-parallel tap changer has 4 effective static contacts, and these 4 effective static contacts are connected to the 2#, 3#, 4#, and 5# tap taps in sequence, and the second group of moving and static contact switching mechanisms has 2 effective static contacts, and these 2 effective static contacts are connected to the 2# and 5# tap taps in sequence; the moving contact of the series-parallel tap changer is sequentially switched between the corresponding static contacts to form three switch positions, and when the moving contact of the first group of moving and static contact switching mechanisms connects the effective static contacts of the 3# and 4# tap taps, the moving contact of the second group of moving and static contact switching mechanisms connects the effective static contacts of the 2# and 5# tap taps.

[0015] Furthermore, for a voltage-regulating transformer with more than three gears, the parallel connection of the tap turns is achieved by adding a transition static contact in the two sets of moving and static contact switching mechanisms of the series-parallel tap changer, so that the number of switch gears of the series-parallel tap changer is greater than the voltage regulating gear, and the switch gear switching sequence of the series-parallel tap changer is consistent with the voltage regulating sequence of the transformer.

[0016] Furthermore, the oil-immersed distribution transformer is a five-speed voltage regulating transformer, the first tap winding and the second tap winding each have two sections of tap turns, and the series-parallel tap switch has 5 voltage regulating gears; when the series-parallel tap switch is in the first gear position, all common turns and tap turns in the first tap winding and the second tap winding are operated in series; when the series-parallel tap switch is in the fifth gear position, only common turns in the first tap winding and the second tap winding are operated in series; when the series-parallel tap switch is in the third gear position, two sections of tap turns in the first tap winding and two sections of tap turns in the second tap winding are connected in parallel and then operated in series with the common turns; when the series-parallel tap switch is in the second gear or the fourth gear position, a section of tap turns in the first tap winding and the second tap winding can be selectively connected in parallel to participate in the operation.

[0017] Furthermore, the three tapping taps of the two sections of tapped turns in the first tapped winding are represented by 2#, 4#, and 6# respectively according to the number of series turns from most to least, and the three tapping taps of the two sections of tapped turns in the second tapped winding are represented by 3#, 5#, and 7# respectively according to the number of series turns from most to least; the first group of dynamic and static contact switching mechanisms of the series-parallel tap changer has 8 effective static contacts, and these 8 effective static contacts are connected to 2#, 3#, 4#, 3#, 6#, 5#, 6#, 7# in sequence. 7# tap tap, the second group of moving-static contact switching mechanisms has at least two effective static contacts, and these two effective static contacts are connected to the 2# and 7# tap taps in sequence; the moving contacts of the series-parallel tap changer are sequentially switched between the corresponding static contacts to form seven switch positions, when the moving contacts of the first group of moving-static contact switching mechanisms connect the effective static contacts of the 3# and 6# tap taps, the moving contacts of the second group of moving-static contact switching mechanisms connect the effective static contacts of the 2# and 7# tap taps.

[0018] Furthermore, when the moving contacts of the first group of moving-static contact switching mechanisms connect the effective static contacts of the 3# and 4# tap taps, the moving contacts of the second group of moving-static contact switching mechanisms connect the effective static contacts of the 2# and 5# tap taps; or, when the moving contacts of the first group of moving-static contact switching mechanisms connect the effective static contacts of the 5# and 6# tap taps, the moving contacts of the second group of moving-static contact switching mechanisms connect the effective static contacts of the 4# and 7# tap taps.

[0019] Furthermore, for the dry-type distribution transformer, the tap turns of the first tap winding and the second tap winding are connected by a shorting piece, and the tap taps of the tap turns of the first tap winding and the second tap winding are respectively connected to the tap terminals on the tap panel, and when the distribution transformer is in at least one intermediate gear state, the tap turns in the first tap winding and the second tap winding are connected in parallel by two shorting pieces in parallel with the corresponding tap terminals.

[0020] Furthermore, on the tap panel, by changing the connection position between the tap terminal of the tap panel and each tap tap and / or adding a transition terminal connected to the corresponding tap tap, the series or parallel connection of the shorting piece to the tap turns is facilitated.

[0021] Furthermore, for a three-speed dry-type distribution transformer, the tap panel has four tap terminals, which are respectively connected to the corresponding four tap taps, and by changing the wiring position of each tap terminal, the series or parallel connection of the tap turns can be achieved through short-circuit pieces of the same specification; for a five-speed dry-type distribution transformer, the tap panel has six tap terminals, which are respectively connected to the corresponding six tap taps, and transition terminals can be selectively added according to the number of gears of the tap turns in parallel, and the transition terminals are connected to the corresponding tap taps, and by changing the wiring position of each tap terminal and the transition terminal, the series or parallel connection of the tap turns can be achieved through short-circuit pieces of the same specification.

[0022] The present invention discloses a series-parallel tapping device for reducing the idle rate of distribution transformer tap turns, comprising a series-parallel tapping switch installed in an oil tank of the distribution transformer, wherein the series-parallel tapping switch comprises an operating mechanism, a first moving-static contact switching mechanism and a second moving-static contact switching mechanism, wherein the first moving-static contact switching mechanism and the second moving-static contact switching mechanism both comprise a static contact assembly and a dynamic contact assembly matched with the static contact assembly, wherein the static contact assembly of the first moving-static contact switching mechanism and the static contact assembly of the second moving-static contact switching mechanism are relatively fixed. The operating mechanism is transmission-connected with the moving contact assembly of the first moving-static contact switching mechanism and the moving contact assembly of the second moving-static contact switching mechanism, and is used to drive the moving contact assembly to slide and switch synchronously and sequentially on the corresponding static contact assembly. The static contact assembly of the first moving-static contact switching mechanism and the static contact assembly of the second moving-static contact switching mechanism are respectively connected to the tap taps in the first tap winding and the second tap winding of the high-voltage winding of the distribution transformer according to the above-mentioned series-parallel tapping method for reducing the idle rate of the distribution transformer tap turns.

[0023] Furthermore, the static contacts connected to the same tap in the first moving-static contact switching mechanism and the second moving-static contact switching mechanism are connected via wires.

[0024] Furthermore, the first moving-static contact switching mechanism and the second moving-static contact switching mechanism both adopt a three-phase synchronous strip tap switch structure, and the static contact assembly of the first moving-static contact switching mechanism and the static contact assembly of the second moving-static contact switching mechanism are arranged horizontally or vertically; the operating mechanism is transmission-connected to the first moving-static contact switching mechanism and / or the second moving-static contact switching mechanism through a gear rack mechanism or a flexible sleeve line mechanism, and is used to drive the moving contact assembly to sequentially move and switch the tap position on the corresponding static contact assembly.

[0025] Furthermore, the first moving-static contact switching mechanism and the second moving-static contact switching mechanism both include three-phase synchronous strip-shaped tap changer units with the same structure, and the three-phase synchronous strip-shaped tap changer units adopt a straight-line or triangular layout.

[0026] 3. Beneficial effects

[0027] Compared with the existing known technologies, the technical solution provided by the present invention has the following significant effects:

[0028] (1) A series-parallel tapping method for reducing the idle rate of distribution transformer tap turns of the present invention utilizes a series-parallel tapping switch or a shorting piece to realize the parallel operation of the idle tap turns of the distribution transformer, and has the following effects: ① When the original wire diameter of the tap turns is maintained, the idle tap turns can be operated in parallel because the intermediate gear can reduce the operating loss of the distribution transformer in the intermediate gear (especially the rated gear); ② When the rated gear operation assessment index of the transformer is met, the copper usage of the winding can be reduced, the material cost of the distribution transformer is reduced, and the filling rate of the transformer winding and the economy of the transformer are improved; ③ By reasonably setting the cross-sectional area of ​​the winding conductor, a balance can be achieved between the operating loss and the economy of the distribution transformer;

[0029] (2) A series-parallel tapping method for reducing the idle rate of tap turns of a distribution transformer of the present invention, for an oil-immersed distribution transformer, the tap turns of a first tap winding and a second tap winding are connected by a series-parallel tap switch, and the series-parallel tap switch is designed with two sets of moving and static contact switching mechanisms connected to the tap taps of the corresponding tap turns, and the parallel operation of the idle tap turns of the distribution transformer is realized by the two sets of moving and static contact switching mechanisms, so that the multi-speed voltage regulation operation of the oil-immersed distribution transformer is simple and convenient;

[0030] (3) A series-parallel tapping method for reducing the idle rate of the tap turns of a distribution transformer of the present invention, in which two sets of moving and static contact switching mechanisms are controlled synchronously in a series-parallel tap changer, and a set of operating mechanisms can be used to simultaneously control the movement of the two sets of moving and static contact switching mechanisms, making the operation faster and more convenient;

[0031] (4) A series-parallel tapping method for reducing the idle rate of the tap turns of a distribution transformer of the present invention, wherein the series-parallel tapping switch adopts 3 or 5 voltage regulating gears, which can be applied to the most commonly used three-gear and five-gear distribution transformers, and is more practical;

[0032] (5) The present invention provides a series-parallel tapping method for reducing the idle rate of the tap turns of a distribution transformer. Through the ingenious connection design between the static contact of the tap changer and the tap tap of the winding, the idle tap turns of the distribution transformer can be operated in parallel at the intermediate gear (rated gear), and the voltage regulation gear sequence of the tap changer is consistent with the gear sequence of the existing tap changer. The design is ingenious and reasonable, easy to operate, and easy to implement on an oil-immersed transformer;

[0033] (6) The present invention provides a series-parallel tapping method for reducing the idle rate of the tap turns of the distribution transformer. For a dry-type distribution transformer, the tap turns in the first tap winding and the second tap winding are connected in parallel by connecting two shorting pieces in parallel with the corresponding tapping terminals. The structure is simple, and it is easy to connect the idle tapping turns in parallel. The implementation process is simple and convenient. In addition, by changing the connection position of the tapping terminals of the tapping panel with each tap tap and / or adding transition terminals connected to the corresponding tap tap, the tap turns can be connected in series or in parallel by shorting pieces of the same specification, making the tapping operation of the dry-type distribution transformer simpler and more convenient, without the trouble of making a variety of shorting pieces, and having better operability and economy.

[0034] (7) A series-parallel tapping device for reducing the idle rate of tap turns of a distribution transformer of the present invention, wherein the series-parallel tapping switch comprises an operating mechanism, a first movable-static contact switching mechanism and a second movable-static contact switching mechanism, wherein the first movable-static contact switching mechanism and the second movable-static contact switching mechanism both comprise a static contact assembly and a movable contact assembly matched with the static contact assembly, wherein the static contact assembly of the first movable-static contact switching mechanism and the static contact assembly of the second movable-static contact switching mechanism are fixedly connected via a connecting plate, and the operating mechanism is transmission-connected to the movable contact assembly of the first movable-static contact switching mechanism and the movable contact assembly of the second movable-static contact switching mechanism, and is used to drive the movable contact assembly to synchronously slide and switch on the corresponding static contact assembly, thereby ensuring the linkage control of the two sets of movable-static contact switching mechanisms, and having a simple structure and flexible operation;

[0035] (8) A series-parallel tapping device for reducing the idle rate of tap turns of a distribution transformer of the present invention, wherein the static contacts connected to the same tapping tap in the first moving-static contact switching mechanism and the second moving-static contact switching mechanism are connected by a wire, and the static contacts in the two sets of moving-static contact switching mechanisms can be connected before leaving the factory, without the need for secondary connection by the user, and the installation in the transformer is more convenient;

[0036] (9) A series-parallel tapping device for reducing the idle rate of tap turns of a distribution transformer of the present invention, wherein the static contact assembly of the first moving-static contact switching mechanism and the static contact assembly of the second moving-static contact switching mechanism are arranged horizontally or vertically, and the layout form can be reasonably selected according to the space of the transformer oil tank, which is convenient for the installation of the tap switch in the transformer oil tank and ensures the compactness of the structure of the tap switch;

[0037] (10) A series-parallel tapping device for reducing the idle rate of tap turns of a distribution transformer of the present invention, wherein the operating mechanism is transmission-connected to the first movable-static contact switching mechanism and / or the second movable-static contact switching mechanism through a gear rack mechanism or a flexible sleeve wire mechanism, and is used to drive the movable contact assembly to sequentially move and switch the tapping position on the corresponding static contact assembly. The transmission control is direct and reliable, so that the operation of the tap switch is flexible and stable, and the series-parallel tapping device is easy to be flexibly arranged in the transformer;

[0038] (11) The present invention is a series-parallel tapping device for reducing the idle rate of distribution transformer tap turns, wherein the first moving and static contact switching mechanism and the second moving and static contact switching mechanism both adopt a three-phase synchronous strip tapping switch structure, and the three-phase synchronous strip tapping switch unit adopts a straight line or triangular layout, which can be applicable to rectangular transformers and triangular three-dimensional transformers. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the connection structure of three tapping positions of an existing three-speed distribution transformer;

[0040] Figure 2 It is a schematic diagram of the connection structure of five tapping positions of an existing five-speed distribution transformer;

[0041] Figure 3 It is a structural schematic diagram of a five-speed strip tap changer of an existing oil-immersed transformer;

[0042] Figure 4 It is a relationship diagram between the gear position and voltage corresponding to the tap switch of the five-speed transformer of the existing oil-immersed transformer;

[0043] Figure 5 A schematic diagram of the connection structure of three tapping gears in a series-parallel tapping method for reducing the idle rate of tap turns of a distribution transformer according to the present invention;

[0044] Figure 6 A schematic diagram of the voltage regulating gear tapping states corresponding to the three switch positions of the series-parallel tap changer in the present invention;

[0045] Figure 7 A relationship diagram between the gear position and the voltage corresponding to the three switch positions of the three-gear series-parallel tap changer in the present invention;

[0046] Figure 8 It is a front structural schematic diagram of a vertically arranged three-speed series-parallel tap changer in the present invention;

[0047] Fig. 9 It is a schematic diagram of a top view of a vertically arranged three-speed series-parallel tap changer in the present invention;

[0048] Fig.10It is a front structural schematic diagram of a horizontal arrangement of a three-speed series-parallel tap changer in the present invention;

[0049] Fig.11 It is a schematic diagram of a top view of a horizontally arranged three-speed series-parallel tap changer in the present invention;

[0050] Fig.12 It is a schematic diagram of the connection structure of five tapping gears in a series-parallel tapping method for reducing the idle rate of tap turns of a distribution transformer according to the present invention;

[0051] Fig.13 It is a connection diagram of the static contacts and the tapping taps in two sets of moving and static contact switching mechanisms in a series-parallel tapping method for reducing the idle rate of the tapping turns of a distribution transformer of the present invention (three-speed parallel connection);

[0052] Fig.14 It is a schematic diagram of the voltage regulating gear tapping state corresponding to the seven switch positions of the five-gear series-parallel tap changer in the present invention (three gears in parallel);

[0053] Fig.15 The figure is a relationship diagram between the gear position and the voltage corresponding to the seven switch positions of the five-gear series-parallel tap changer in the present invention (three-gear parallel connection);

[0054] Fig.16 A schematic diagram of the connection structure of five tapping gears (three gears and four gears in parallel) in a series-parallel tapping method for reducing the idle rate of tap turns of a distribution transformer according to the present invention;

[0055] Fig.17 It is a connection diagram of the static contacts and the tapping taps in two sets of moving and static contact switching mechanisms in a series-parallel tapping method for reducing the idle rate of the tapping turns of a distribution transformer of the present invention (three-gear and four-gear parallel connection);

[0056] Fig.18 It is a schematic diagram of the voltage regulating gear tapping state corresponding to the seven switch positions of the five-gear series-parallel tap changer in the present invention (three gears and four gears in parallel);

[0057] Fig.19 The figure is a relationship diagram between the gear position and the voltage corresponding to the seven switch positions of the five-gear series-parallel tap changer in the present invention (three-gear and four-gear parallel connection);

[0058] Fig. 20 A schematic diagram of the connection structure of five tapping gears (two gears, three gears, and four gears in parallel) in a series-parallel tapping method for reducing the idle rate of tap turns of a distribution transformer according to the present invention;

[0059] Fig.21It is a connection diagram of the static contacts and the tapping taps in two groups of moving and static contact switching mechanisms in a series-parallel tapping method for reducing the idle rate of the tapping turns of the distribution transformer of the present invention (two-gear, three-gear, four-gear parallel connection);

[0060] Fig. 22 It is a schematic diagram of the voltage regulating gear tapping state corresponding to the seven switch positions of the five-gear series-parallel tap changer in the present invention (second gear, third gear, and fourth gear in parallel);

[0061] Fig.23 The figure is a relationship diagram between the gear position and the voltage corresponding to the seven switch positions of the five-gear series-parallel tap changer in the present invention (two-gear, three-gear, and four-gear parallel connection);

[0062] Fig.24 It is a front structural schematic diagram of a five-speed series-parallel tap changer in the present invention arranged vertically;

[0063] Fig.25 It is a schematic diagram of a top view of a vertically arranged five-speed series-parallel tap changer in the present invention;

[0064] Fig.26 It is a front structural schematic diagram of a horizontal arrangement of a five-speed series-parallel tap changer in the present invention;

[0065] Fig. 27 It is a schematic diagram of a top view of a horizontally arranged five-speed series-parallel tap changer in the present invention;

[0066] Fig.28 It is a structural schematic diagram of a series-parallel tap changer using a flexible sleeve line mechanism transmission in the present invention;

[0067] Fig.29 It is a structural schematic diagram of another series-parallel tap changer using a flexible sleeve line mechanism transmission in the present invention;

[0068] Fig.30 It is a wiring diagram of the tap panel of the three-speed dry-type distribution transformer in the present invention;

[0069] Fig.31 It is a wiring diagram of the tap panel of the five-speed dry-type distribution transformer in the present invention (three speeds in parallel);

[0070] Fig.32 It is a wiring diagram of the tapping panel of the five-speed dry-type distribution transformer in the present invention (three-speed and four-speed in parallel);

[0071] Fig.33 The figure is a wiring diagram of the tapping panel of the five-speed dry-type distribution transformer in the present invention (second, third and fourth speeds are connected in parallel).

[0072] Explanation of the symbols in the schematic diagram:

[0073] 1. Operating mechanism; 2. Strip switch assembly; 2-1. Stationary contact bracket; 2-2. Stationary contact; 2-3. Moving contact bracket; 2-4. Moving contact; 2-5. Rack; 2-6. Gear; 3. Oil tank; 4. First moving and static contact switching mechanism; 4-1. First stationary contact bracket; 4-2. First stationary contact; 4-3. First moving contact bracket; 4-4. First moving contact; 4-5. First rack; 4-6. First gear; 5. Second moving and static contact switching mechanism; 5-1. Second stationary contact bracket; 5-2. Second stationary contact; 5-3. Second moving contact bracket; 5-4. Second moving contact; 5-5. Second rack; 5-6. Second gear; 6. Connecting plate; 7. Flexible sleeve line mechanism; 8. Tap panel; 9. Tap terminal; 10. Shorting piece; 11. Transition terminal; L0. Common line turn; L1. Tap line turn. DETAILED DESCRIPTION

[0074] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings.

[0075] Combination Figure 5 , Fig.12 , Fig.16 , Fig. 20 as well as Figure 30 to Figure 32 As shown, a series-parallel tapping method for reducing the idle rate of tap turns of a distribution transformer of the present invention, the distribution transformer has a high-voltage winding with the same three-phase structure, Figure 5 , Fig.12 , Fig.16 , Fig. 20 as well as Figure 30 to Figure 32 In the above, the A-phase high-voltage winding is taken as an example. The high-voltage winding includes two parts, a first tap winding and a second tap winding. The first tap winding is formed by M segments of tap turns L1 connected in series, and the second tap winding is formed by N segments of tap turns L1 connected in series. M and N are both positive integers ≥ 1, and |MN|=0 or 1, that is, M=N or the difference between the two is 1. Each segment of the tap turns L1 of the first tap winding and the second tap winding has a tap tap. The first tap winding and / or the second tap winding also includes a common turn L0 connected in series with the corresponding tap turn L1. In this embodiment, the first tap winding and the second tap winding both have a common turn L0, and the common turn L0 participates in the operation in all gears, and the tap turn L1 selectively participates in the operation according to the adjustment of the gear. The first tap winding and the second tap winding are connected via a series-parallel tap switch or a shorting piece 10 capable of changing the number of running turns of the high-voltage winding, and when the distribution transformer is in at least one intermediate gear state, the first tap winding and the second tap winding have tap turns L1 connected in parallel via the series-parallel tap switch or two shorting pieces 10, and the total number of turns of the tap turns L1 connected in parallel in the first tap winding and the second tap winding is equal, so as to avoid the generation of circulating current.

[0076] When a series-parallel tap changer is used to connect the first tap winding and the second tap winding, it is suitable for oil-immersed distribution transformers. The series-parallel tap changer is designed with two groups of dynamic and static contact switching mechanisms connected to the tapping taps of the corresponding tap turns L1. When the series-parallel tap changer is in the first gear position, all common turns L0 and tap turns L1 in the first tap winding and the second tap winding are connected in series. At this time, all turns of the high-voltage winding participate in the operation, and the corresponding voltage is the largest; when the series-parallel tap changer is in the last gear position, the common turns L0 in the first tap winding and the second tap winding are connected in series. At this time, all tap turns L1 do not participate in the operation, the number of running turns of the high-voltage winding is the least, and the corresponding voltage is also the smallest; when the series-parallel tap changer is in the middle gear position, there is at least one middle gear state, and the tap turns L1 in the first tap winding and the second tap winding are connected in parallel through the mutual connection of the static contacts in the two groups of dynamic and static contact switching mechanisms, and then the original idle tap turns L1 are connected in parallel to participate in the operation, so that the cross-sectional area of ​​the turns of the parallel part is increased.

[0077] The two sets of moving and static contact switching mechanisms of the series-parallel tap changer can be independently controlled by two sets of control mechanisms, or can be controlled in linkage by the same control mechanism. In order to facilitate the operation of the series-parallel tap changer, it is preferred that the two sets of moving and static contact switching mechanisms of the series-parallel tap changer be controlled in synchronous linkage, that is, the switch positions of the two sets of moving and static contact switching mechanisms are switched synchronously and linkage, and the movement of the two sets of moving and static contact switching mechanisms can be controlled simultaneously by one set of operating mechanisms, which makes the operation faster and more convenient.

[0078] When the shorting piece 10 is used to connect the first tap winding and the second tap winding, it is suitable for dry-type distribution transformers. Each tapping tap of the tapping turns L1 of the first tap winding and the second tap winding is respectively connected to the tapping terminal 9 on the tapping panel 8. When the distribution transformer is in at least one intermediate gear state, the tapping turns L1 in the first tap winding and the second tap winding are connected in parallel by connecting two shorting pieces 10 in parallel with the corresponding tapping terminals 9. On the tapping panel 8, by changing the connection position of the tapping terminal 9 of the tapping panel 8 and each tapping tap and / or adding a transition terminal 11 connected to the corresponding tapping tap, the shorting piece 10 is convenient for connecting the tapping turns L1 in series or in parallel, and the tapping turns L1 can be connected in series or in parallel by shorting pieces 10 of the same specification, making the tapping operation of the dry-type distribution transformer simpler and more convenient.

[0079] By adopting the above-mentioned series-parallel tapping method, for the high-voltage winding tapping of the multi-speed voltage-regulating distribution transformer, the parallel operation of the idle tapping turns of the distribution transformer is realized by using the series-parallel tapping switch or the shorting piece, which has the following effects: ① When the original wire diameter of the tapping turns is maintained, since the intermediate gear can make the idle tapping turns run in parallel, the operation loss of the distribution transformer in the intermediate gear (especially the rated gear) can be reduced; ② Under the condition of meeting the rated gear operation assessment index of the transformer, the copper consumption of the winding can be reduced, the material cost of the distribution transformer is reduced, and the filling rate of the transformer winding and the economy of the transformer are improved; in this case, all the tapping turns L1 in the first gear position are operated in series. Although the reduction in the copper consumption of the winding will cause an increase in the operation loss, the current of this gear is small, and the increased operation loss has little effect, and this gear is not the rated gear, which is generally only used when the voltage needs to be increased, and the use time is not long; ③ Through the reasonable setting of the cross-sectional area of ​​the winding conductor, a balance can be achieved between the operation loss and the economy of the distribution transformer, which can reduce the operation loss of the distribution transformer and its manufacturing cost.

[0080] Based on the above-mentioned inventive ideas, the present invention is further described in combination with embodiments, wherein embodiments 1 to 6 are applications of the series-parallel tapping method of the present invention in oil-immersed distribution transformers, and embodiments 7 to 9 are applications of the series-parallel tapping method of the present invention in dry-type distribution transformers.

[0081] [Example 1]

[0082] like Figure 5 As shown, taking the three tapping positions of a three-speed voltage-regulating distribution transformer as an example, a series-parallel tapping method for reducing the idle rate of the tap turns of the distribution transformer in this embodiment is provided. The distribution transformer is a three-speed voltage-regulating transformer with 3 voltage-regulating positions. The first tap winding and the second tap winding both have a section of tap turns L1, that is, M=N=1. In the first position, all common turns L0 and tap turns L1 in the first tap winding and the second tap winding are operated in series; in the second position, the tap turns L1 in the first tap winding and the second tap winding are connected in parallel and then operated in series with the common turns L0; in the third position, only the common turns L0 in the first tap winding and the second tap winding are operated in series. Specifically, Figure 5As shown, the two tapping ends of the tapping turns L1 in the first tapping winding are represented by 2# and 4# respectively according to the number of series turns from most to least, and the two tapping ends of the tapping turns L1 in the second tapping winding are represented by 3# and 5# respectively according to the number of series turns from most to least. For a three-speed oil-immersed distribution transformer, the tapping turns L1 of the first tapping winding and the second tapping winding are connected through a series-parallel tapping switch, and the series-parallel tapping switch also has three voltage regulation gears. Accordingly, when the series-parallel tapping switch is in the first gear position, all the common turns L0 and tapping turns L1 in the first tapping winding and the second tapping winding operate in series; when the series-parallel tapping switch is in the second gear position, the tapping turns L1 in the first tapping winding and the second tapping winding are connected in parallel and operate in series with the common turns L0; when the series-parallel tapping switch is in the third gear position, only the common turns L0 in the first tapping winding and the second tapping winding operate in series. As shown Figure 6 As shown, the series-parallel tap changer is designed with two groups of moving and static contact switching mechanisms that are controlled in linkage and connected to the tapping taps of the corresponding tapping turns L1. The first group of moving and static contact switching mechanisms has 4 effective static contacts, and these 4 effective static contacts are connected to the 2#, 3#, 4#, and 5# tapping taps in sequence. The second group of moving and static contact switching mechanisms has 2 effective static contacts, and these 2 effective static contacts are connected to the 2# and 5# tapping taps in sequence. The so-called "effective static contact" refers to the static contact that actually participates in the wiring. In order to maintain the structural consistency of the two groups of moving and static contact switching mechanisms, an empty static contact that is not connected to the wiring can also be set in the second group of moving and static contact switching mechanisms. The moving contacts of the series-parallel tap changer are switched sequentially between the corresponding static contacts to form three switch positions. When the moving contacts of the first set of moving and static contact switching mechanisms connect the effective static contacts of the 3# and 4# tap taps, the moving contacts of the second set of moving and static contact switching mechanisms connect the effective static contacts of the 2# and 5# tap taps, thereby connecting the two sections of tap turns L1 in parallel in the second position (rated position).

[0083] Figure 6 The diagram is a schematic diagram of the voltage regulating gear tapping status corresponding to the three switch positions of the series-parallel tap changer. Figure 7 The figure is a relationship diagram between the gear position and voltage corresponding to the three switch positions of the three-speed series-parallel tap changer. Figure 6 and Figure 7 It can be seen that for a 10KV three-speed oil-immersed voltage-regulating transformer, the tap voltage is adjusted by 5% per gear, i.e., the voltage of gear 1 is 10500V, the voltage of gear 2 (rated gear) is 10000V, and the voltage of gear 3 is 9500V. When the series-parallel tap changer is in the first switch position, the first set of dynamic and static contact switching mechanism connects the 2# and 3# tapping taps, and the corresponding static contact in the second set of dynamic and static contact switching mechanism is "empty" and the 2# tapping tap is on. Figure 5In the middle 1st gear state, the 2# and 3# tapping taps are operated in series; when the series-parallel tap changer is in the second switch position, the first set of dynamic and static contact switching mechanisms connects the 3# and 4# tapping taps, and the second set of dynamic and static contact switching mechanisms connects the 2# and 5# tapping taps. Figure 5 In the middle 2nd gear state, the tap turns L1 of the first tap winding and the second tap winding are connected in parallel for operation; when the series-parallel tap changer is in the third switch position, the first set of dynamic and static contact switching mechanisms connects the 4# and 5# tap taps, and the corresponding static contacts in the second set of dynamic and static contact switching mechanisms are the 5# tap tap and "empty", and at this time it is still Figure 5 In the middle 3rd gear state, the 4# and 5# tapping taps are operated in series. For the three-gear oil-immersed voltage-regulating distribution transformer, the ingenious connection design between the static contact of the tap changer and the tapping tap of the winding enables the distribution transformer to operate the idle tapping turns in parallel in the 2nd gear (rated gear), and the voltage-regulating gear sequence of the tap changer is consistent with the existing tap changer gear sequence. The design is ingenious and reasonable, and easy to operate.

[0084] like Figure 8 and Fig. 9 As shown, in order to facilitate the application of the above series-parallel tapping method in a three-speed oil-immersed distribution transformer, this embodiment also provides a series-parallel tapping device for reducing the idle rate of the distribution transformer tap turns, which includes a series-parallel tap switch installed in the distribution transformer oil tank 3, the series-parallel tap switch includes an operating mechanism 1, a first moving-static contact switching mechanism 4 and a second moving-static contact switching mechanism 5, the first moving-static contact switching mechanism 4 and the second moving-static contact switching mechanism 5 both include a static contact assembly and a moving contact assembly matched with the static contact assembly, the static contact assembly of the first moving-static contact switching mechanism 4 and the static contact assembly of the second moving-static contact switching mechanism 5 The head assemblies are relatively fixedly connected, and specifically, the two groups of static contact assemblies can be fixed together by a connecting plate 6. The operating mechanism 1 is transmission-connected with the moving contact assembly of the first moving-static contact switching mechanism 4 and the moving contact assembly of the second moving-static contact switching mechanism 5, and is used to drive the moving contact assembly to slide and switch synchronously and sequentially on the corresponding static contact assembly. The static contact assembly of the first moving-static contact switching mechanism 4 and the static contact assembly of the second moving-static contact switching mechanism 5 are respectively connected to the tap taps in the first tap winding and the second tap winding of the high-voltage winding of the distribution transformer according to the above-mentioned series-parallel tapping method for reducing the idle rate of the distribution transformer tap turns. The above-mentioned series-parallel tapping switch can ensure the linkage control of the two groups of moving-static contact switching mechanisms, with a simple structure and flexible operation.

[0085] catch Figure 8 and Fig. 9As shown, in this embodiment, the static contact assembly of the first static and dynamic contact switching mechanism 4 and the static contact assembly of the second static and dynamic contact switching mechanism 5 are arranged vertically, that is, the first static and dynamic contact switching mechanism 4 and the second static and dynamic contact switching mechanism 5 are arranged up and down, so that the horizontal structure of the series-parallel tap changer is more compact, which is convenient for the installation of the tap changer in the transformer oil tank, and ensures the compactness of the structure of the tap changer. The first static and dynamic contact switching mechanism 4 and the second static and dynamic contact switching mechanism 5 have the same structure, the static contact assembly of the first static and dynamic contact switching mechanism 4 includes a first static contact bracket 4-1 and a first static contact 4-2 installed on the first static contact bracket 4-1 at intervals, the dynamic contact assembly of the first static and dynamic contact switching mechanism 4 includes a first dynamic contact bracket 4-3 and a first dynamic contact 4-4 installed on the first dynamic contact bracket 4-3, the first dynamic contact 4-4 is slidably matched with the first static contact bracket 4-1, and can be slidably switched between the first static contacts 4-2 to achieve the connection of two adjacent first static contacts 4-2. The static contact assembly of the second static and dynamic contact switching mechanism 5 includes a second static contact bracket 5-1 and a second static contact 5-2 installed at intervals on the second static contact bracket 5-1. The dynamic contact assembly of the second static and dynamic contact switching mechanism 5 includes a second dynamic contact bracket 5-3 and a second dynamic contact 5-4 installed on the second dynamic contact bracket 5-3. The second dynamic contact 5-4 is slidably matched with the second static contact bracket 5-1, and can be slidably switched between the second static contacts 5-2 to achieve the connection between two adjacent second static contacts 5-2. As a tap changer of a three-speed voltage-regulating transformer, four static contacts are provided on each static contact bracket. The dynamic contact slides and switches between adjacent static contacts to achieve the connection between two static contacts, thereby forming three switch positions. Preferably, the static contacts connected to the same tapping tap in the first static and dynamic contact switching mechanism 4 and the second static and dynamic contact switching mechanism 5 are connected by wires, that is, Figure 8 The 2# second static contact 5-2 is connected to the 2# first static contact 4-2 through a wire, and the 5# second static contact 5-2 is connected to the 5# first static contact 4-2 through a wire. In this way, during installation, it is only necessary to connect each second static contact 5-2 to the tap of the transformer high-voltage winding. The static contacts in the two sets of moving and static contact switching mechanisms can be connected at the factory, without the need for secondary connection by the user, to prevent problems such as wiring errors, and to make installation in the transformer more convenient.

[0086] In this embodiment, the first moving-static contact switching mechanism 4 and the second moving-static contact switching mechanism 5 both adopt a three-phase synchronous strip tap switch structure, that is, the first moving-static contact switching mechanism 4 and the second moving-static contact switching mechanism 5 respectively have three groups of mutually cooperating static contact assemblies and moving contact assemblies, and each phase of the static contact assembly and the moving contact assembly constitute a phase strip tap switch unit, and the three-phase moving contact assembly is synchronously controlled by the operating mechanism 1 to achieve the synchronous tapping and voltage regulation operation of the three-phase high-voltage winding of the transformer. In order to adapt to different similar transformers, the first moving-static contact switching mechanism 4 and the second moving-static contact switching mechanism 5 both include a three-phase synchronous strip tap switch unit with the same structure, and the three-phase synchronous strip tap switch unit adopts a straight line or triangular layout, where the straight line layout is as follows: Figure 8 and Fig. 9 As shown, it can be applied to rectangular transformers. The triangular layout can refer to the strip tap changer of the existing triangular three-dimensional transformer. Its three-phase synchronous strip tap changer unit is arranged in a triangular structure and can be applied to the triangular three-dimensional transformer.

[0087] The operating mechanism 1 is connected to the first moving-static contact switching mechanism 4 and / or the second moving-static contact switching mechanism 5 via a gear rack mechanism or a flexible sleeve line mechanism 7, and is used to drive the moving contact assembly to sequentially move and switch the tap position on the corresponding static contact assembly. Figure 8 and Fig. 9 A specific structure using a gear rack mechanism for transmission is provided. Specifically, a first gear 4-6 and a second gear 5-6 can be set on the rotating shaft of the operating mechanism 1, a first rack 4-5 meshing with the first gear 4-6 can be set on the first moving contact bracket 4-3, and a second rack 5-5 meshing with the second gear 5-6 can be set on the second moving contact bracket 5-3. The first gear 4-6 and the second gear 5-6 are driven to rotate by turning the knob of the operating mechanism 1, and the first rack 4-5 and the second rack 5-5 are driven to move synchronously, thereby realizing the sliding control of the first moving contact bracket 4-3 and the second moving contact bracket 5-3. Of course, the moving contact assembly of the first moving-static contact switching mechanism 4 and the moving contact assembly of the second moving-static contact switching mechanism 5 are also fixedly connected by the connecting plate 6, that is, the first moving contact bracket 4-3 and the second moving contact bracket 5-3 are fixedly connected together by the connecting plate 6, and the first moving contact bracket 4-3 and the second moving contact bracket 5-3 are synchronously driven to slide by a group of gear rack mechanisms. Fig.28 and Fig.29 The specific structure of the flexible sleeve line mechanism 7 transmission is given, wherein Fig.29The connection position of the first moving and static contact switching mechanism 4, the second moving and static contact switching mechanism 5 and the flexible sleeve line mechanism 7 is transferred to the side of the moving and static contact switching mechanism through a connecting piece, which can reduce the length of the tap switch and facilitate installation and use in a small-capacity transformer. The application of the flexible sleeve line mechanism 7 in the tap switch can be found in the "A Transformer Tap Switch Based on Brake Line Control" disclosed in Chinese Patent No. 202021839441.8. The operating mechanism 1 and the tap switch body are connected by a flexible sleeve line (brake line). The operating mechanism 1 can be used to remotely and synchronously control the gear switching of the tap switch one-to-one, and the installation position of the operating mechanism 1 and the tap switch can be flexibly selected, which not only facilitates the installation of the transformer tap switch, but also facilitates the gear switching operation of the tap switch, making the installation and operation of the tap switch more flexible and convenient.

[0088] [Example 2]

[0089] like Fig.10 and Fig.11 As shown, a series-parallel tapping method and device for reducing the idle rate of distribution transformer tap turns in this embodiment has the same basic structure and working principle as that in embodiment 1, except that:

[0090] In the three-speed series-parallel tap changer, the static contact assembly of the first moving-static contact switching mechanism 4 and the static contact assembly of the second moving-static contact switching mechanism 5 are arranged horizontally, that is, the first moving-static contact switching mechanism 4 and the second moving-static contact switching mechanism 5 adopt a front-to-back layout, which makes the vertical structure of the series-parallel tap changer more compact, facilitates the installation of the tap changer in the transformer oil tank, and ensures the compactness of the structure of the tap changer.

[0091] [Example 3]

[0092] like Figures 12 to 15 As shown, taking the five tapping positions of a five-speed voltage-regulating distribution transformer as an example, a series-parallel tapping method for reducing the idle rate of the tap turns of the distribution transformer in this embodiment is provided. The distribution transformer is a five-speed voltage-regulating transformer with 5 voltage-regulating positions. The first tap winding and the second tap winding both have two sections of tap turns L1, that is, M=N=2. In the first position, all common turns L0 and tap turns L1 in the first tap winding and the second tap winding are operated in series; in the fifth position, only the common turns L0 in the first tap winding and the second tap winding are operated in series; in the third position, the two sections of tap turns L1 in the first tap winding and the two sections of tap turns L1 in the second tap winding are connected in parallel and then operated in series with the common turns L0. In the second or fourth position, a section of the tap turns L1 in the first tap winding and the second tap winding can be selectively connected in parallel to participate in the operation, which is described in detail in the following embodiments. Specifically, Fig.12As shown in the figure, the three tapping taps of the two tapping turns L1 in the first tapping winding are represented by 2#, 4#, and 6# respectively according to the number of series turns from most to least. The 2# tapping tap represents that the common turn L0 in the first tapping winding and the two tapping turns L1 are connected in series to participate in the operation, the 4# tapping tap represents that the common turn L0 in the first tapping winding and the one tapping turn L1 are connected in series to participate in the operation, and the 6# tapping tap represents that only the common turn L0 in the first tapping winding participates in the operation. The three taps of the two-section tap turns L1 in the second tap winding are represented by 3#, 5#, and 7# respectively according to the number of series turns from most to least. The 3# tap tap represents that the common turns L0 and the two-section tap turns L1 in the second tap winding are connected in series to participate in the operation, the 5# tap tap represents that the common turns L0 and the one-section tap turns L1 in the second tap winding are connected in series to participate in the operation, and the 7# tap tap represents that only the common turns L0 in the second tap winding participate in the operation. For a five-speed oil-immersed distribution transformer, the tap turns L1 of the first tap winding and the second tap winding are connected through a series-parallel tap changer, which also has five voltage adjustment gears; when the series-parallel tap changer is in the first gear position, all common turns L0 and tap turns L1 in the first tap winding and the second tap winding are operated in series; when the series-parallel tap changer is in the fifth gear position, only the common turns L0 in the first tap winding and the second tap winding are operated in series; when the series-parallel tap changer is in the third gear position, two sections of tap turns L1 in the first tap winding and two sections of tap turns L1 in the second tap winding are connected in parallel and then operated in series with the common turns L0; when the series-parallel tap changer is in the second gear or the fourth gear position, a section of tap turns L1 in the first tap winding and the second tap winding can be selectively connected in parallel to participate in the operation. Fig.13 and Fig.14 As shown, the first group of dynamic and static contact switching mechanisms of the series-parallel tap changer has 8 effective static contacts, and these 8 effective static contacts are connected to the 2#, 3#, 4#, 3#, 6#, 5#, 6#, and 7# tap taps in sequence, and the second group of dynamic and static contact switching mechanisms has at least 2 effective static contacts, and these 2 effective static contacts are connected to the 2# and 7# tap taps in sequence. The so-called "effective static contact" refers to the static contact that actually participates in the wiring. In order to maintain the structural consistency of the two groups of dynamic and static contact switching mechanisms, an empty static contact that is not connected to the wiring can also be set in the second group of dynamic and static contact switching mechanisms. The moving contacts of the series-parallel tap changer are switched sequentially between the corresponding static contacts to form seven switch positions, that is, two adjacent static contacts are connected through the moving contact to form one switch position. When the moving contacts of the first group of moving and static contact switching mechanisms connect the effective static contacts of the 3# and 6# tap taps, the moving contacts of the second group of moving and static contact switching mechanisms connect the effective static contacts of the 2# and 7# tap taps, thereby connecting the tap turns L1 in parallel at the 3rd position (rated position).

[0093] The number of switch positions is not necessarily the same as the number of voltage adjustment gears. Some of the seven switch positions have the same voltage and belong to the same voltage adjustment gear. The extra switch positions are used for transition during tap switch adjustment. Fig.15 As shown, for a 10KV five-speed voltage regulating transformer, the tap voltage regulation is adjusted by 2.5% for each speed, that is, the voltage of speed 1 is 10500V, the voltage of speed 2 is 10250V, the voltage of speed 3 (rated speed) is 10000V, the voltage of speed 4 is 9750V, and the voltage of speed 5 is 9500V. Fig.14 As shown in the figure, when the series-parallel tap changer is in the first switch position, the first set of moving and static contact switching mechanisms connects the 2# and 3# tap taps, and the corresponding static contacts in the second set of moving and static contact switching mechanisms are "empty". Fig.12 Middle 1st gear state; when the series-parallel tap changer is in the second switch position, the first set of dynamic and static contact switching mechanism connects the 3# and 4# tap taps, and the corresponding static contact in the second set of dynamic and static contact switching mechanism is "empty". Fig.12 Middle 2 gear state; when the series-parallel tap changer is in the third switch position, the first set of dynamic and static contact switching mechanism connects the 4# and 3# tap taps, and the corresponding static contact in the second set of dynamic and static contact switching mechanism is "empty" and 2# tap tap, and it is still Fig.12 Middle 2 gear state; when the series-parallel tap changer is in the fourth switch position, the first set of dynamic and static contact switching mechanism connects the 3# and 6# tap taps, and the second set of dynamic and static contact switching mechanism connects the 2# and 7# tap taps. Fig.12 In the middle 3rd gear state, the two sections of tap turns L1 of the first tap winding and the two sections of tap turns L1 of the second tap winding are connected in parallel; when the series-parallel tap changer is in the fifth switch position, the first group of dynamic and static contact switching mechanisms connects the 6# and 5# tap taps, and the second group of dynamic and static contact switching mechanisms connects the 7# tap tap and "empty", which is now Fig.12 Middle 4th gear state; when the series-parallel tap changer is in the sixth switch position, the first group of dynamic and static contact switching mechanism connects the 5# and 6# tap taps, and the corresponding static contact in the second group of dynamic and static contact switching mechanism is "empty". Fig.12 Middle 4th gear state; when the series-parallel tap changer is in the seventh switch position, the first group of dynamic and static contact switching mechanism connects the 6# and 7# tap taps, and the corresponding static contact in the second group of dynamic and static contact switching mechanism is "empty". Fig.12For the five-speed voltage-regulating distribution transformer, the ingenious connection design between the static contact of the tap changer and the tap tap of the winding enables the distribution transformer to operate the idle tap turns in parallel at the third gear (rated gear), and the voltage-regulating gear sequence of the tap changer is consistent with the existing gear sequence of the tap changer. The design is ingenious and reasonable, easy to operate, and easy to implement on oil-immersed transformers.

[0094] See also Figure 24 to Figure 27 As shown, in order to facilitate the application of the above series-parallel tapping method in a five-speed oil-immersed distribution transformer, this embodiment also provides a series-parallel tapping device for reducing the idle rate of the distribution transformer tap turns, and its basic structure is the same as that of the above embodiments 1 and 2. Fig.24 and Fig.25 It is shown that the static contact assembly of the first static contact switching mechanism 4 and the static contact assembly of the second static contact switching mechanism 5 are arranged vertically, that is, the first static contact switching mechanism 4 and the second static contact switching mechanism 5 are arranged up and down; Fig.26 and Fig. 27 It is shown that the static contact assembly of the first moving and static contact switching mechanism 4 and the static contact assembly of the second moving and static contact switching mechanism 5 are arranged horizontally, that is, the first moving and static contact switching mechanism 4 and the second moving and static contact switching mechanism 5 adopt a front-to-back layout. Different from the three-speed series-parallel tapping device in Example 1 and Example 2, this embodiment is a five-speed series-parallel tapping device, each static contact bracket is provided with 8 static contacts, and the moving contact slides and switches between adjacent static contacts to achieve the connection of two static contacts, thereby forming seven switch gears.

[0095] [Example 4]

[0096] like Figures 16 to 19 As shown, a series-parallel tapping method and device for reducing the idle rate of distribution transformer tap turns in this embodiment has the same basic structure and working principle as that in embodiment 3, except that:

[0097] When the series-parallel tap changer is in the second or fourth gear position, a section of tap turns L1 in the first tap winding and the second tap winding also participates in the operation in parallel, so that the idle tap turns can also participate in the operation in parallel in the second or fourth gear. That is, when the moving contact of the first group of moving and static contact switching mechanisms connects the effective static contacts of the 3# and 4# tap taps, the moving contact of the second group of moving and static contact switching mechanisms connects the effective static contacts of the 2# and 5# tap taps, and the tap turns in parallel in the second gear are realized; when the moving contact of the first group of moving and static contact switching mechanisms connects the effective static contacts of the 5# and 6# tap taps, the moving contact of the second group of moving and static contact switching mechanisms connects the effective static contacts of the 4# and 7# tap taps, and the tap turns in parallel in the fourth gear are realized.

[0098] Specific as Fig.17As shown, the two groups of moving and static contact switching mechanisms of the series-parallel tap changer respectively have 8 static contacts, and the 8 static contacts are switched with the moving contact to form seven switch positions, that is, two adjacent static contacts are connected through the moving contact to form a switch position, and the 8 static contacts in the first group of moving and static contact switching mechanisms are connected to the 2#, 3#, 4#, 3#, 6#, 5#, 6#, and 7# tap taps in sequence, and the 4th to 7th static contacts in the second group of moving and static contact switching mechanisms are connected to the 2#, 7#, 4#, and 7# tap taps in sequence. Fig.16 In addition to the third gear, the fourth gear also has a design form in which idle tap turns are connected in parallel. Fig.18 and Fig.19 As shown in the figure, when the series-parallel tap changer is in the first switch position, the first set of moving and static contact switching mechanisms connects the 2# and 3# tap taps, and the corresponding static contacts in the second set of moving and static contact switching mechanisms are "empty". Fig.16 Middle 1st gear state; when the series-parallel tap changer is in the second switch position, the first set of dynamic and static contact switching mechanism connects the 3# and 4# tap taps, and the corresponding static contact in the second set of dynamic and static contact switching mechanism is "empty". Fig.16 Middle 2 gear state; when the series-parallel tap changer is in the third switch position, the first set of dynamic and static contact switching mechanism connects the 4# and 3# tap taps, and the corresponding static contact in the second set of dynamic and static contact switching mechanism is "empty" and 2# tap tap, and it is still Fig.16 Middle 2 gear state; when the series-parallel tap changer is in the fourth switch position, the first set of dynamic and static contact switching mechanism connects the 3# and 6# tap taps, and the second set of dynamic and static contact switching mechanism connects the 2# and 7# tap taps. Fig.16 In the middle 3rd gear state, the two sections of tap turns L1 of the first tap winding and the two sections of tap turns L1 of the second tap winding are connected in parallel; when the series-parallel tap changer is in the fifth switch position, the first group of dynamic and static contact switching mechanisms connects the 6# and 5# tap taps, and the second group of dynamic and static contact switching mechanisms connects the 7# and 4# tap taps. Fig.16 In the middle 4th gear state, a section of tapped winding L1 of the first tapped winding is connected to a section of tapped winding L1 of the second tapped winding in parallel operation; when the series-parallel tap changer is in the sixth switch position, the first group of dynamic and static contact switching mechanisms connects the 5# and 6# tap taps, and the second group of dynamic and static contact switching mechanisms connects the 4# and 7# tap taps. At this time, it is still Fig.16In the middle 4th gear state, a section of tapped winding L1 of the first tapped winding is connected to a section of tapped winding L1 of the second tapped winding in parallel operation; when the series-parallel tap changer is in the seventh switch position, the first set of dynamic and static contact switching mechanisms connects the 6# and 7# tapping taps, and the corresponding static contacts in the second set of dynamic and static contact switching mechanisms are the 7# tapping tap and "empty", which is Fig.16 For the five-speed voltage-regulating distribution transformer, the idle tap turns can be connected in parallel in both the third gear (rated gear) and the fourth gear, and the order of the tap changer voltage-regulating gears is consistent with the order of the existing tap changer gears. The method for implementing the design of the idle tap turns in parallel in the second gear is similar to the method for implementing the design of the idle tap turns in parallel in the fourth gear.

[0099] [Example 5]

[0100] like Figure 20 to Figure 23 As shown, a series-parallel tapping method and device for reducing the idle rate of distribution transformer tap turns in this embodiment has the same basic structure and working principle as that in embodiment 3, except that:

[0101] When the series-parallel tap changer is in the second and fourth gear positions, a section of tap turns L1 in the first tap winding and the second tap winding are also connected in parallel for operation, so that the idle tap turns can be connected in parallel for operation in the second, third and fourth gears.

[0102] like Fig.21 As shown, the two groups of moving and static contact switching mechanisms of the series-parallel tap changer respectively have 8 static contacts, and the 8 static contacts are switched with the moving contact to form seven switch positions, that is, two adjacent static contacts are connected through the moving contact to form a switch position, and the 8 static contacts in the first group of moving and static contact switching mechanisms are connected to the 2#, 3#, 4#, 3#, 6#, 5#, 6#, and 7# tap taps in sequence, and the 2nd to 7th static contacts in the second group of moving and static contact switching mechanisms are connected to the 2#, 5#, 2#, 7#, 4#, and 7# tap taps in sequence. Fig. 20 In addition to the third gear, the second and fourth gears also have idle tap turns running in parallel. Fig. 22 and Fig.23 As shown in the figure, when the series-parallel tap changer is in the first switch position, the first set of moving and static contact switching mechanisms connects the 2# and 3# tap taps, and the corresponding static contacts in the second set of moving and static contact switching mechanisms are "empty" and the 2# tap tap. Fig. 20 Middle 1st gear state; when the series-parallel tap changer is in the second switch position, the first set of dynamic and static contact switching mechanism connects the 3# and 4# tap taps, and the second set of dynamic and static contact switching mechanism connects the 2# and 5# tap taps. Fig. 20In the middle 2nd gear state, a section of tapped turns L1 of the first tapped winding is connected in parallel with a section of tapped turns L1 of the second tapped winding; when the series-parallel tap changer is in the third switch position, the first group of dynamic and static contact switching mechanisms connects the 4# and 3# tap taps, and the second group of dynamic and static contact switching mechanisms connects the 5# and 2# tap taps. Fig. 20 In the middle 2nd gear state, a section of tapped turns L1 of the first tapped winding and a section of tapped turns L1 of the second tapped winding are connected in parallel; when the series-parallel tap changer is in the fourth switch position, the first group of dynamic and static contact switching mechanisms connects the 3# and 6# tap taps, and the second group of dynamic and static contact switching mechanisms connects the 2# and 7# tap taps. Fig. 20 In the middle 3rd gear state, the two sections of tap turns L1 of the first tap winding and the two sections of tap turns L1 of the second tap winding are connected in parallel; when the series-parallel tap changer is in the fifth switch position, the first group of dynamic and static contact switching mechanisms connects the 6# and 5# tap taps, and the second group of dynamic and static contact switching mechanisms connects the 7# and 4# tap taps. Fig. 20 In the middle 4th gear state, a section of tapped winding L1 of the first tapped winding is connected to a section of tapped winding L1 of the second tapped winding in parallel operation; when the series-parallel tap changer is in the sixth switch position, the first group of dynamic and static contact switching mechanisms connects the 5# and 6# tap taps, and the second group of dynamic and static contact switching mechanisms connects the 4# and 7# tap taps. At this time, it is still Fig. 20 In the middle 4th gear state, a section of tapped winding L1 of the first tapped winding is connected to a section of tapped winding L1 of the second tapped winding in parallel operation; when the series-parallel tap changer is in the seventh switch position, the first set of dynamic and static contact switching mechanisms connects the 6# and 7# tapping taps, and the corresponding static contacts in the second set of dynamic and static contact switching mechanisms are the 7# tapping tap and "empty", which is Fig. 20 For the five-speed voltage-regulating distribution transformer, the idle tap turns can be operated in parallel in the 2nd, 3rd (rated) and 4th gears, and the tap changer voltage-regulating gear sequence is consistent with the existing tap changer gear sequence.

[0103] In the five-speed series-parallel tap changers in the above-mentioned embodiments 3 to 5, there are two 2-speed and two 4-speed in the seven switch positions to form transitional gears, and the two 2-speed are adjacent, and the two 4-speed are adjacent, so that the corresponding number of voltage regulating gears can be marked on each switch position on the operating mechanism 1 of the series-parallel tap changer, without changing the operating sequence of the voltage regulating gears, and the idle tap turns can be operated in parallel in the 3rd gear (rated gear) and the 2nd gear or the 4th gear, so that the operating loss and economy of the distribution transformer can be well taken into account.

[0104] [Example 6]

[0105] In order not to change the operation sequence of the voltage regulating gears of the series-parallel tap changer, it is ensured that when the tap changer is operated in the same direction, the voltage regulating gears are from small to large or from large to small. On the basis of the above-mentioned embodiments 3 to 5, for a voltage regulating transformer with more than three gears, the series-parallel tap changer is used to realize the transition of the voltage regulating gear by adding a transition static contact, that is, the general design principle is: by adding a transition static contact in the two sets of moving and static contact switching mechanisms to realize the parallel connection of the tap turns L1, the number of switch gears of the series-parallel tap changer is more than the voltage regulating gear, and the switch gear switching sequence of the series-parallel tap changer is consistent with the voltage regulating sequence of the transformer. The extra switch gears are used as transition gears for voltage regulation of the tap changer.

[0106] [Example 7]

[0107] The present embodiment provides a series-parallel tapping method for reducing the idle rate of tap turns of a distribution transformer. The principle of the series-parallel tapping method is the same as that of the above-mentioned embodiments 1 to 6, except that the series-parallel tapping method of the present embodiment is applied to a dry-type distribution transformer.

[0108] For a dry-type distribution transformer, each tapping tap of the tapping turns L1 of the first tapping winding and the second tapping winding is led out through a tapping panel 8, and a shorting piece 10 is used to connect different tapping taps together during tapping to achieve a change in the number of turns of the high-voltage winding. That is, the tapping turns L1 of the first tapping winding and the second tapping winding are connected by a shorting piece 10, and each tapping tap of the tapping turns L1 of the first tapping winding and the second tapping winding is respectively connected to a tapping terminal 9 on the tapping panel 8. When the distribution transformer is in at least one intermediate gear state, the tapping turns L1 in the first tapping winding and the second tapping winding are connected in parallel by two shorting pieces 10 in parallel with the corresponding tapping terminals 9. In this way, based on the above-mentioned series-parallel tapping method, the parallel operation of idle tapping turns can also be achieved in a dry-type distribution transformer to reduce the operating loss of the distribution transformer in the intermediate gear (especially the rated gear).

[0109] When shorting different tap terminals 9 with shorting pieces 10 on the tap panel 8, due to the connection position limitation between the tap terminals 9 and the tapping taps, when two shorting pieces 10 are used to connect the tap turns L1 in parallel, shorting pieces 10 of different specifications are required, which brings unnecessary trouble to the transformer manufacturer and user. To this end, as a preferred design scheme, the following design ideas are given for the layout of the terminals on the tap panel 8 and the connection relationship between the terminals and the tapping taps: on the tap panel 8, by changing the connection position between the tap terminals 9 of the tap panel 8 and each tapping tap and / or adding a transition terminal 11 connected to the corresponding tapping tap, it is convenient for the shorting piece 10 to connect the tap turns L1 in series or in parallel, and then the tap turns are connected in series or in parallel by shorting pieces of the same specification, so that the tapping operation of the dry-type distribution transformer is simpler and more convenient, without the trouble of making a variety of shorting pieces, and the operability and economy are better.

[0110] In order to better understand the design concept of the connection terminals of the above-mentioned tapping panel 8, the following is further explained in combination with the design examples of three-speed dry-type distribution transformers and five-speed dry-type distribution transformers.

[0111] [Example 8]

[0112] like Fig.30 As shown, for a three-speed dry-type distribution transformer, the tap panel 8 has four tap terminals 9, which are respectively connected to the corresponding four tap taps. By changing the connection position of each tap terminal 9, the tap turns L1 can be connected in series or in parallel through the shorting pieces 10 of the same specification. Specifically, the four tap terminals 9 are arranged in a diamond structure on the tap panel 8, combined with Figure 5 As shown, the 2# and 4# tap taps of the tap turns L1 in the first tap winding are connected to two tap terminals 9 on the diagonal, and the 3# and 5# tap taps of the tap turns L1 in the second tap winding are connected to two tap terminals 9 on the other diagonal. In this way, in the 2nd gear position, the two shorting pieces 10 are arranged in parallel without crossing, and the distances between the tap terminals 9 that need to be short-circuited in different gears are the same. Therefore, it is only necessary to change the connection position of the tap terminals 9 of the tap panel 8 and each tap tap to complete the series or parallel connection of the tap turns through shorting pieces 10 of the same specification.

[0113] [Example 9]

[0114] like Figure 31 to Figure 33As shown, for a five-speed dry-type distribution transformer, the tap panel 8 has six tap terminals 9, and the six tap terminals 9 are respectively connected to the corresponding six tap taps. A transition terminal 11 can be selectively added according to the number of gears in which the tap turns L1 are connected in parallel. The transition terminal 11 is connected to the corresponding tap tap, and by changing the wiring positions of each tap terminal 9 and the transition terminal 11, the series or parallel connection of the tap turns L1 can be achieved through the short-circuit pieces 10 of the same specification.

[0115] It can be seen from the above embodiments that for a five-speed distribution transformer, except for the third speed (rated speed) in which idle tap turns can be operated in parallel, idle tap turns can also be selectively operated in parallel in the second speed and the fourth speed.

[0116] Fig.31 A design scheme for connecting the tap turns in parallel in the third gear (rated gear) is provided. At this time, the tap turns L1 can be connected in series or in parallel through the shorting pieces 10 of the same specification only by changing the connection positions of the tap terminals 9. Fig.12 and Fig.31 As shown, the six tap terminals 9 are also distributed in a diamond structure on the tap panel 8, forming a layout of three tap terminals 9 in each of two rows on the left and right. The 2#, 4#, and 6# tap taps of the two sections of tap turns L1 in the first tap winding and the 3#, 5#, and 7# tap taps of the two sections of tap turns L1 in the second tap winding are respectively connected to the corresponding tap terminals 9, among which the 2#, 3#, and 4# tap taps are connected to the three tap terminals 9 on the left side from top to bottom, and the 5#, 6#, and 7# tap taps are connected to the three tap terminals 9 on the right side from bottom to top. In the 1st position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 2# and 3# tap taps; in the 2nd position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 3# and 4# tap taps; in the 3rd position, two shorting pieces 10 are used to respectively connect the tap terminals 9 corresponding to the 2# and 7# tap taps and the tap terminals 9 corresponding to the 3# and 6# tap taps; in the 4th position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 5# and 6# tap taps; in the 5th position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 6# and 7# tap taps. In this way, in the 3rd gear position, the two shorting pieces 10 are arranged in parallel without crossing, and the distances between the tap terminals 9 that need to be short-circuited in different gears are the same. Therefore, it is only necessary to change the connection position of the tap terminals 9 of the tap panel 8 and each tap tap to complete the series or parallel connection of the tap turns through shorting pieces 10 of the same specification.

[0117] Fig.32A design scheme for connecting the tap turns in parallel in the third gear (rated gear) and the fourth gear is provided. In this case, a transition terminal 11 needs to be added to realize the series or parallel connection of the tap turns L1 using a shorting piece 10 of the same specification. Fig.16 and Fig.32 As shown, the six tap terminals 9 are still distributed in a diamond structure on the tap panel 8, and a transition terminal 11 is added at a row of tap terminals 9, forming a layout of four terminals on the left and three terminals on the right. The 2#, 4#, and 6# tap taps of the two sections of tap turns L1 in the first tap winding and the 3#, 5#, and 7# tap taps of the two sections of tap turns L1 in the second tap winding are respectively connected to the corresponding tap terminals 9 and transition terminals 11, wherein the four terminals on the left are connected to the 7#, 2#, 4#, and 7# tap taps in order from top to bottom, and the three terminals on the right are connected to the 3#, 6#, and 5# tap taps in order from top to bottom. In the 1st position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 2# and 3# tap taps; in the 2nd position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 3# and 4# tap taps; in the 3rd position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 3# and 6# tap taps, and a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 2# tap tap and the transition terminal 11 corresponding to the 7# tap tap; in the 4th position, two shorting pieces 10 are used to connect the tap terminals 9 corresponding to the 5# and 6# tap taps and the tap terminals 9 corresponding to the 4# and 7# tap taps respectively; in the 5th position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 6# and 7# tap taps. In this way, in the 3rd and 4th gear positions, the two shorting pieces 10 do not cross, and the distances between the tap terminals 9 and the transition terminals 11 that need to be short-circuited in different gears are the same. Therefore, it is only necessary to increase the transition terminals 11 and change the connection positions of the various terminals of the tap panel 8 and the various tap taps to complete the series or parallel connection of the tap turns through shorting pieces 10 of the same specification.

[0118] Fig.33 A design scheme for connecting the tap turns in parallel in the second, third (rated) and fourth gears is provided. In this case, two transition terminals 11 need to be added to realize the series or parallel connection of the tap turns L1 using shorting pieces 10 of the same specification. Fig. 20 and Fig.33 As shown, the six tap terminals 9 are still distributed in a diamond structure on the tap panel 8, and a transition terminal 11 is added at each of the two rows of tap terminals 9, forming a layout of four terminals on the left and four terminals on the right. The connection positions of the six tap terminals 9 and the corresponding tapping points are the same as Fig.32Similarly, the transition terminal 11 added on the upper left side is connected to the 7# tap, and the transition terminal 11 added on the lower right side is connected to the 4# tap. In the 1st position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 2# and 3# tap taps; in the 2nd position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 3# and 4# tap taps, and a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 5# tap tap with the transition terminal 11 corresponding to the 4# tap tap; in the 3rd position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 3# and 6# tap taps, and a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 2# tap tap with the transition terminal 11 corresponding to the 7# tap tap; in the 4th position, two shorting pieces 10 are used to connect the tap terminals 9 corresponding to the 5# and 6# tap taps and the tap terminals 9 corresponding to the 4# and 7# tap taps respectively; in the 5th position, a shorting piece 10 is used to connect the tap terminals 9 corresponding to the 6# and 7# tap taps. In this way, in the 2nd, 3rd and 4th gear positions, the two shorting pieces 10 do not cross, and the distances between the tap terminals 9 and the transition terminals 11 that need to be short-circuited in different gears are the same. Therefore, it is only necessary to increase the transition terminals 11 and change the connection positions of the various terminals of the tap panel 8 and the various tap taps to complete the series or parallel connection of the tap turns through shorting pieces 10 of the same specification.

[0119] The above embodiments only describe the series-parallel tapping method of the commonly used three-speed voltage-regulating distribution transformer and the five-speed voltage-regulating distribution transformer and the series-parallel tapping switch corresponding to the oil-immersed transformer. When there are four-speed or five-speed or more voltage-regulating distribution transformers, the series-parallel tapping method of the present invention for reducing the idle rate of the distribution transformer tap turns is also applicable. Generally speaking, when an even number of tap positions is required, at this time |MN|=1. Taking the fourth gear as an example, the first tap winding can use two sections of tap turns L1 in series, that is, M=2, and the first tap winding can use one section of tap turns L1 in series, that is, N=1. The three tap taps of the first tap winding are represented by 2#, 4#, and 6# respectively according to the number of series turns from most to least, and the two tap taps of the second tap winding are represented by 3# and 5# respectively according to the number of series turns from most to least. At this time, four-speed voltage regulation can be formed, and the tap turns idle in the middle gear can also be connected in parallel to participate in the operation using the series-parallel tapping method and series-parallel tap changer in the present invention, which will not be described in detail.

[0120] The present invention discloses a series-parallel tapping method and device for reducing the idle rate of distribution transformer tap turns, which utilizes series-parallel tapping switches or shorting pieces to realize the parallel operation of idle tap turns of distribution transformer, and has the following effects: ① when the original wire diameter of the tap turns is maintained, the idle tap turns can be operated in parallel because the intermediate gear can reduce the operation loss of the distribution transformer in the intermediate gear (especially the rated gear); ② when the rated gear operation assessment index of the transformer is met, the copper usage of the winding can be reduced, the material cost of the distribution transformer is reduced, and the filling rate of the transformer winding and the economy of the transformer are improved; ③ through the reasonable setting of the cross-sectional area of ​​the winding conductor, the operation loss and economy of the distribution transformer can be balanced.

[0121] The present invention and its embodiments are described schematically above, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and creatively designs a structure and an embodiment similar to the technical solution without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A series-parallel tapping method for reducing the idle rate of distribution transformer tap turns, characterized in that: The high-voltage winding of the distribution transformer comprises a first tap winding and a second tap winding, wherein the first tap winding is formed by connecting M segments of tap turns (L1) in series, and the second tap winding is formed by connecting N segments of tap turns (L1) in series, wherein M and N are both positive integers ≥ 1, and |MN|=0 or 1, each segment of the tap turns (L1) of the first tap winding and the second tap winding has a tap tap, and the first tap winding and / or the second tap winding further comprises a tap tap connected to the corresponding tap turns (L1) The first tap winding and the second tap winding are connected via a series-parallel tap switch or a shorting piece (10) capable of changing the number of running turns of the high-voltage winding, and when the distribution transformer is in at least one intermediate gear state, the first tap winding and the second tap winding have tap turns (L1) connected in parallel via the series-parallel tap switch or two shorting pieces (10), and the total number of turns of the tap turns (L1) connected in parallel in the first tap winding and the second tap winding is equal.

2. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 1, characterized in that: For an oil-immersed distribution transformer, the tap turns (L1) of the first tap winding and the second tap winding are connected via a series-parallel tap changer, and the series-parallel tap changer is designed with two sets of moving and static contact switching mechanisms connected to the tap taps of the corresponding tap turns (L1). When the series-parallel tap changer is in an intermediate position, there is at least one intermediate position state, and the tap turns (L1) in the first tap winding and the second tap winding are connected in parallel by connecting the static contacts in the two sets of moving and static contact switching mechanisms.

3. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 2, characterized in that: In the series-parallel tap changer, two sets of moving and static contact switching mechanisms are controlled by synchronous linkage.

4. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 2 or 3, characterized in that: The oil-immersed distribution transformer is a three-speed voltage regulating transformer. The first tap winding and the second tap winding both have a section of tap turns (L1), and the series-parallel tap switch has three voltage regulating gears. When the series-parallel tap switch is in the first gear position, all common turns (L0) and tap turns (L1) in the first tap winding and the second tap winding are connected in series. When the series-parallel tap switch is in the second gear position, the tap turns (L1) in the first tap winding and the second tap winding are connected in parallel and connected in series with the common turns (L0). When the series-parallel tap switch is in the third gear position, only the common turns (L0) in the first tap winding and the second tap winding are connected in series.

5. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 4, characterized in that: The two tapping points of the tapping turns (L1) in the first tapping winding are represented by 2# and 4# respectively according to the number of series turns from most to least, and the two tapping points of the tapping turns (L1) in the second tapping winding are represented by 3# and 5# respectively according to the number of series turns from most to least; the first group of moving and static contact switching mechanisms of the series-parallel tap changer has 4 effective static contacts, and the 4 effective static contacts are connected to the 2#, 3#, 4# and 5# tapping taps in sequence, and the second group of moving and static contact switching mechanisms has 2 effective static contacts, and the 2 effective static contacts are connected to the 2# and 5# tapping taps in sequence; the moving contact of the series-parallel tap changer is sequentially switched between the corresponding static contacts to form three switch positions, and when the moving contact of the first group of moving and static contact switching mechanisms connects the effective static contacts connected to the 3# and 4# tapping taps, the moving contact of the second group of moving and static contact switching mechanisms connects the effective static contacts of the 2# and 5# tapping taps.

6. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 2 or 3, characterized in that: For a voltage regulating transformer with more than three gears, the parallel connection of the tap turns (L1) is achieved by adding transition static contacts in the two sets of moving and static contact switching mechanisms of the series-parallel tap changer, so that the number of switch gears of the series-parallel tap changer is greater than the voltage regulating gear, and the switching sequence of the switch gears of the series-parallel tap changer is consistent with the voltage regulating sequence of the transformer.

7. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 6, characterized in that: The oil-immersed distribution transformer is a five-speed voltage regulating transformer. The first tap winding and the second tap winding both have two sections of tap turns (L1), and the series-parallel tap switch has five voltage regulating gears. When the series-parallel tap switch is in the first gear position, all common turns (L0) and tap turns (L1) in the first tap winding and the second tap winding are connected in series. When the series-parallel tap switch is in the fifth gear position, only the common turns (L0) in the first tap winding and the second tap winding are connected in series. When the series-parallel tap switch is in the third gear position, two sections of tap turns (L1) in the first tap winding and two sections of tap turns (L1) in the second tap winding are connected in parallel and then connected in series with the common turns (L0). When the series-parallel tap switch is in the second gear or the fourth gear position, one section of tap turns (L1) in the first tap winding and the second tap winding can be selectively connected in parallel to participate in the operation.

8. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 7, characterized in that: The three tapping taps of the two-section tapping turns (L1) in the first tapping winding are represented by 2#, 4#, and 6# respectively according to the number of series turns, and the three tapping taps of the two-section tapping turns (L1) in the second tapping winding are represented by 3#, 5#, and 7# respectively according to the number of series turns. The first group of dynamic and static contact switching mechanisms of the series-parallel tap changer has 8 effective static contacts, and the 8 effective static contacts are connected to 2#, 3#, 4#, 3#, 6#, 5#, and 6# in sequence. , 7# tap taps, the second group of moving-static contact switching mechanisms has at least two effective static contacts, and the two effective static contacts are connected to the 2# and 7# tap taps in sequence; the moving contacts of the series-parallel tap changer are sequentially switched between the corresponding static contacts to form seven switch positions, when the moving contacts of the first group of moving-static contact switching mechanisms connect the effective static contacts of the 3# and 6# tap taps, the moving contacts of the second group of moving-static contact switching mechanisms connect the effective static contacts of the 2# and 7# tap taps.

9. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 8, characterized in that: When the moving contacts of the first group of moving-static contact switching mechanisms connect the effective static contacts of the 3# and 4# tap taps, the moving contacts of the second group of moving-static contact switching mechanisms connect the effective static contacts of the 2# and 5# tap taps; or, when the moving contacts of the first group of moving-static contact switching mechanisms connect the effective static contacts of the 5# and 6# tap taps, the moving contacts of the second group of moving-static contact switching mechanisms connect the effective static contacts of the 4# and 7# tap taps.

10. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 1, characterized in that: For a dry-type distribution transformer, the tap turns (L1) of the first tap winding and the second tap winding are connected via a shorting piece (10), and the tap taps of the tap turns (L1) of the first tap winding and the second tap winding are respectively connected to tap terminals (9) on a tap panel (8), and when the distribution transformer is in at least one intermediate gear state, the tap turns (L1) in the first tap winding and the second tap winding are connected in parallel by connecting two shorting pieces (10) in parallel to the corresponding tap terminals (9).

11. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 10, characterized in that: On the tapping panel (8), by changing the connection position between the tapping terminal (9) of the tapping panel (8) and each tapping tap and / or adding a transition terminal (11) connected to the corresponding tapping tap, the series or parallel connection of the tapping turns (L1) by the shorting piece (10) is facilitated.

12. The series-parallel tapping method for reducing the idle rate of distribution transformer tap turns according to claim 11, characterized in that: For a three-speed dry-type distribution transformer, the tap panel (8) has four tap terminals (9), which are respectively connected to four corresponding tap taps, and by changing the connection positions of the tap terminals (9), the series or parallel connection of the tap turns (L1) can be achieved through shorting pieces (10) of the same specification; for a five-speed dry-type distribution transformer, the tap panel (8) has six tap terminals (9), which are respectively connected to six corresponding tap taps, and a transition terminal (11) can be selectively added according to the number of gears of the tap turns (L1) connected in parallel, and the transition terminal (11) is connected to the corresponding tap tap, and by changing the connection positions of the tap terminals (9) and the transition terminal (11), the series or parallel connection of the tap turns (L1) can be achieved through shorting pieces (10) of the same specification.

13. A series-parallel tapping device for reducing the idle rate of tap turns of a distribution transformer, comprising a series-parallel tapping switch installed in an oil tank (3) of the distribution transformer, characterized in that: The series-parallel tap changer comprises an operating mechanism (1), a first moving-static contact switching mechanism (4) and a second moving-static contact switching mechanism (5); the first moving-static contact switching mechanism (4) and the second moving-static contact switching mechanism (5) both comprise a static contact assembly and a dynamic contact assembly matched with the static contact assembly; the static contact assembly of the first moving-static contact switching mechanism (4) and the static contact assembly of the second moving-static contact switching mechanism (5) are relatively fixedly connected; the operating mechanism (1) and the first moving-static contact switching mechanism (4) are connected to each other; The moving contact assembly of the first moving-static contact switching mechanism (4) and the moving contact assembly of the second moving-static contact switching mechanism (5) are transmission connected to drive the moving contact assembly to slide and switch synchronously and sequentially on the corresponding static contact assembly. The static contact assembly of the first moving-static contact switching mechanism (4) and the static contact assembly of the second moving-static contact switching mechanism (5) are respectively connected to the tap taps in the first tap winding and the second tap winding of the high-voltage winding of the distribution transformer according to the series-parallel tapping method for reducing the idle rate of the distribution transformer tap turns as described in any one of claims 3 to 9.

14. The series-parallel tapping device for reducing the idle rate of distribution transformer tap turns according to claim 13, characterized in that: The first moving-static contact switching mechanism (4) and the second moving-static contact switching mechanism (5) are connected to the same tapping point via a wire.

15. The series-parallel tapping device for reducing the idle rate of distribution transformer tap turns according to claim 13 or 14, characterized in that: The first moving-static contact switching mechanism (4) and the second moving-static contact switching mechanism (5) both adopt a three-phase synchronous strip tap switch structure, and the static contact assembly of the first moving-static contact switching mechanism (4) and the static contact assembly of the second moving-static contact switching mechanism (5) are arranged horizontally or vertically; the operating mechanism (1) is connected to the first moving-static contact switching mechanism (4) and / or the second moving-static contact switching mechanism (5) through a gear rack mechanism or a flexible sleeve line mechanism (7), and is used to drive the moving contact assembly to sequentially move and switch the tap position on the corresponding static contact assembly.

16. The series-parallel tapping device for reducing the idle rate of distribution transformer tap turns according to claim 15, characterized in that: The first moving and static contact switching mechanism (4) and the second moving and static contact switching mechanism (5) both comprise three-phase synchronous strip-shaped tapping switch units with the same structure, and the three-phase synchronous strip-shaped tapping switch units adopt a straight-line or triangular layout.

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