A staggered parallel nine-speed transformer on-load voltage regulation circuit with polarity conversion

Abstract

The present invention relates to the field of distribution transformers. The present invention provides a staggered parallel nine-speed transformer on-load voltage regulation circuit with polarity conversion, including a main winding, a polarity conversion switch, a voltage regulating winding, a transition switching unit, a rated voltage branch, and five voltage regulating branches; the present invention sets a polarity conversion switch between the main winding and the voltage regulating winding, and realizes positive and negative voltage regulation by adjusting the independent contact connection end of the polarity conversion switch; one end of each voltage regulating branch is respectively connected to the two end taps and each middle tap of the voltage regulating winding; the other end is adjacently staggered in parallel to form two groups, respectively connected to the two input ends of the transition switching unit, the input end of the rated voltage branch is connected to the main winding output end tap, and the output end of the rated voltage branch is connected to the output end of the voltage regulating circuit. The beneficial effects of the present invention are to reduce the on-off frequency of the on-off switch, increase the service life of the corresponding voltage regulating switch, and in the voltage regulation process, the transition voltage changes with the voltage regulating gear, and there is no need to jump the gear to regulate the voltage.

Description

Technical Field

[0001] The invention relates to the field of distribution transformers, and in particular to an on-load voltage regulation circuit of a transformer. Background Art

[0002] In the patent with application number 201610121960 and title: "A permanent magnetic vacuum on-load voltage regulating switch, transformer and on-load voltage regulating method", a method for on-load voltage regulating is provided, which uses two vacuum interrupters to form the main circuit and transition circuit structure respectively. The key points of this technical scheme are: during normal operation, the vacuum interrupter of the main circuit is connected, and the main circuit is in the on state, the vacuum interrupter of the transition circuit is disconnected, and the transition circuit is in the off state, and the voltage regulating winding connected to the main circuit determines the external voltage supply gear of the circuit. When switching gears, the vacuum interrupter of the transition circuit is closed first, and the transition circuit is in the on state, and then the vacuum interrupter of the main circuit is disconnected, and the main circuit is in the off state. At this time, the shift switch completes the shift without current, and no arc is generated. The transition circuit provides a transition voltage for the circuit when the gear is switched to ensure that the circuit will not interrupt the external voltage supply. However, the multi-speed voltage regulating circuit designed according to this scheme has the following shortcomings:

[0003] 1. Each time the gear is switched, the vacuum interrupter of the main circuit must be opened and closed once, and the transition circuit must also be closed and opened once. The vacuum interrupters of the main circuit and transition circuit are the devices with the highest switching frequency in the circuit. The upper limit of their switching times determines the service life of the voltage regulator designed according to the circuit. According to the standard requirements, the mechanical life of the on-load voltage regulator must reach 500,000 times, that is, the voltage regulator performs 500,000 tap change operations when the contacts are not energized and all the tapping ranges are used. According to this voltage regulation circuit, the on-load voltage regulator with 5 gears performs a voltage regulation cycle, and the main circuit and transition circuit will operate 4*50=2 million times. For the on-load voltage regulator with 9 gears, the main circuit and transition circuit will operate 8*50=4 million times. At present, the mechanical life of the vacuum interrupter is required to be between 800,000 and 1.2 million times. It can be seen that the mechanical life of the voltage regulator produced according to this voltage regulation circuit is a severe test, and it is estimated that the mechanical life cannot meet the standard requirements.

[0004] 2. The transition circuit is fixed to a certain tap. Any voltage adjustment must first return to this fixed tap, and then adjust to the gear that needs voltage adjustment, commonly known as jump-shift voltage adjustment. The instantaneous change of voltage will produce a very high amplitude operating overvoltage. The higher the instantaneous rate of voltage change, the higher the amplitude of the overvoltage generated, which is extremely harmful to electronic products connected to the power grid. Therefore, the standard does not allow jump-shift voltage adjustment.

[0005] The patent with application number: 201721680735.9, titled: "A method for on-load voltage regulation using a double-throw switch", has made improvements to Patent 201610121960: the structure of the tapping coil is simpler; the transition circuit is connected to the rated gear instead of the end of the main winding of the transformer, so that the voltage fluctuation is smaller when shifting. This patent has multiple variations. But the two fundamental points are the same as Patent 201610121960: 1. Every time the gear is switched, the vacuum interrupter of the main circuit must be opened and closed once, and the transition circuit must also be closed and opened once. The upper limit of the number of on-off times determines the service life of the voltage regulating switch designed according to the circuit. 2. Its transition circuit is fixedly connected to the tap of the main winding, and the voltage regulation is still a jump gear voltage regulation, which is not allowed by the standard.

[0006] In the patent application number 201820286271.1, the patent 201721680735.9 was improved by adding a transition circuit selection switch (the number varies according to the voltage regulating gear, and 5 gears require 2 transition circuit selection switches). The transition circuit is not fixedly connected to the main tapping gear of the voltage regulating winding, but changes with the gear through the transition circuit selection switch. However, the defect that "every time the gear is switched, the main circuit vacuum interrupter must be opened and closed once, and the transition circuit must also be closed and opened once. The upper limit of its on-off times determines the service life of the voltage regulating switch designed according to this circuit" remains unchanged. And as the number of switch gears increases, the number of transition circuit selection switches also increases, and the switch structure tends to be complex. Summary of the invention

[0007] The purpose of the present invention is to design a new nine-speed transformer on-load voltage regulation circuit, replace the design of the transition circuit and the main circuit, reduce the on-off frequency of the on-off switch in the circuit during the voltage regulation process, so as to achieve the purpose of increasing the service life of the corresponding voltage regulation switch; in the voltage regulation process, the transition voltage is allowed to be different with the gears switched by the circuit, the voltage fluctuation during the voltage regulation is reduced, and the problem of jump-gear voltage regulation is solved; at the same time, the positive and negative voltage regulation functions are added to the nine-speed voltage regulation circuit, so as to achieve the purpose of reducing the number of voltage regulation windings and reducing the manufacturing cost under the premise of the same gear.

[0008] In order to achieve the purpose of the above invention, the technical scheme of the present invention is a staggered parallel nine-speed transformer on-load voltage regulation circuit with polarity conversion, including a main winding, a voltage regulation winding, a rated voltage branch, a transition switching unit, and five voltage regulation branches; the voltage regulation winding is composed of four sections of voltage regulation coils wound in the same direction and connected end to end in sequence, and the voltage regulation winding includes two end taps and three middle taps, the main winding input end tap is connected to the input end of the voltage regulation circuit, and the main winding output end tap is connected to the common contact of the polarity conversion switch; the two independent contacts of the polarity conversion switch are respectively connected to the two end taps of the voltage regulation winding;

[0009] The transition switching unit is composed of a transition resistor and an on-off switch in parallel. The two ends of the parallel structure are defined as the first input end and the second input end of the transition switching unit, and the second input end also serves as the output end of the voltage regulating circuit. Preferably, the switch uses a vacuum arc extinguishing chamber, and the arc will not pollute the transformer oil. An on-off switch is connected in series on each voltage regulating branch, and one end of the voltage regulating branch is respectively connected to the two end taps and the middle tap of the voltage regulating coil; the other end is adjacently staggered in parallel into two groups, and is respectively connected to the two input ends of the transition switching unit. Preferably, the switch uses a vacuum arc extinguishing chamber, and the arc will not pollute the transformer oil. An on-off switch is connected in series on the rated voltage branch, and one end of the rated voltage branch is connected to the output end of the main winding (the common contact of the polarity conversion switch is also connected to this end); the other end can be connected to any end of the transition switching unit. Preferably, the rated voltage branch is connected to the first input end of the transition switching unit, and the output current does not pass through the switch in the transition switching unit when the rated gear is used; the on-off switch preferably uses a vacuum arc extinguishing chamber, and the arc will not pollute the transformer oil.

[0010] Specifically, four sections of voltage regulating coils are connected end to end, and a voltage regulating winding tap is provided at each end of the voltage regulating coil, wherein adjacent voltage regulating coil ends share a voltage regulating winding tap, and the voltage regulating winding has five taps in total, namely, an upper end tap, a middle upper end tap, a middle end tap, a middle lower end tap, and a lower end tap.

[0011] One end of each of the five voltage regulating branches is connected to a winding tap, and the other end of each voltage regulating branch has two connection methods:

[0012] Connection method 1: a voltage regulating branch connected to the upper tap, a voltage regulating branch connected to the middle tap, and a voltage regulating branch connected to the lower tap, the other ends of the three voltage regulating branches are directly connected to the second input end of the transition switching unit; a voltage regulating branch connected to the middle-upper tap and a voltage regulating branch connected to the middle-lower tap, the other ends of the two voltage regulating branches are connected to the first input end of the transition switching unit.

[0013] Connection method two: a voltage regulating branch connected to the upper tap, a voltage regulating branch connected to the middle tap, and a voltage regulating branch connected to the lower tap, the other ends of the three voltage regulating branches are connected to the first input end of the transition switching unit; a voltage regulating branch connected to the middle-upper tap and a voltage regulating branch connected to the middle-lower tap, the other ends of the two voltage regulating branches are connected to the second input end of the transition switching unit.

[0014] Since the second input end of the transition switching unit is connected to the output end of the entire voltage regulating circuit, the voltage regulating branch connected to the second input end of the transition switching unit is defined as a directly connected voltage regulating branch. Since a parallel resistor and a transition unit on-off switch are connected in series between the first input end of the transition switching unit and the output end of the voltage regulating circuit, the voltage regulating branch connected to the first input end of the transition switching unit is defined as a non-directly connected voltage regulating branch.

[0015] When the polarity conversion switch is in the upper on state, the polarity of the voltage regulating winding connected to the circuit is the same as the polarity of the main winding, and the circuit can perform positive voltage regulation; when the polarity conversion switch is in the lower on state, the polarity of the voltage regulating winding connected to the circuit is opposite to the main winding, and the circuit can perform reverse voltage regulation.

[0016] During the positive voltage regulation process or the reverse voltage regulation process, the voltage regulating winding connected to the circuit can be adjusted to correspond to different gears by selecting to close the on-off switch of any voltage regulating branch separately.

[0017] When the on / off switch of any non-directly connected voltage regulating branch is in a closed state and the on / off switch of the transition switching unit is also in an on state, the voltage regulating circuit is in a normal operating state of the corresponding gear. This state is defined as the normal operating state of the non-directly connected circuit.

[0018] The on-off switch of the direct-connected voltage regulating branch is in a closed state, and the on-off switch of the transition switching unit is in an open state. At this time, the voltage regulating circuit is in a normal operating state of the corresponding gear. This state is defined as the normal working state of the direct-connected circuit.

[0019] During the gear switching process, the structure of alternating direct-connected voltage regulation branches and indirect-connected voltage regulation branches is used to achieve on-load voltage regulation.

[0020] From the perspective of circuit structure, in the technical solution of the present invention, one voltage regulating branch is a direct-connected voltage regulating branch, and the adjacent voltage regulating branch must be a non-direct-connected voltage regulating branch. In the multi-speed transformer voltage regulating circuit under this solution, each voltage regulating branch must be connected in this alternating form.

[0021] In the voltage regulating circuit under this technical solution, the so-called gear switching is to switch from the normal working state of one voltage regulating branch to the normal working state of another adjacent voltage regulating branch, either from the normal working state of the directly connected voltage regulating branch to the normal working state of the indirect connected voltage regulating branch, or from the normal working state of the indirect connected voltage regulating branch to the normal working state of the directly connected voltage regulating branch.

[0022] From the circuit structure point of view, as long as the on-off switch of the transition switching unit is in the off state, the transition resistor is always connected in series between two adjacent voltage regulating branches, which ensures that when the two adjacent voltage regulating branches are in the on state at the same time, the circuit will not be short-circuited, allowing the two voltage regulating branches to be energized at the same time, which ensures that the power supply will not be interrupted during the voltage regulation process.

[0023] Therefore, as long as the on-off switch of the transition switching unit is in the off state, the voltage regulation can begin.

[0024] If it is switched from the normal working state of the direct-connected voltage regulating branch to the normal working state of the non-direct-connected voltage regulating branch, since the direct-connected voltage regulating branch is in the normal working state, the on-off switch of the transition switching unit is already in the off state at this time. Therefore, just close the on-off switch of the corresponding non-direct-connected voltage regulating branch, then open the on-off switch of the corresponding direct-connected voltage regulating branch, and then connect the on-off switch of the transition switching unit, so as to complete a gear switching.

[0025] If the switch is made from the normal working state of the non-direct-connected voltage regulating branch to the normal working state of the direct-connected voltage regulating branch, since the non-direct-connected branch is in the normal working state and the on-off switch of the transition switching unit is in the on state, the on-off switch of the transition switching unit must be disconnected first and then the on-off switch of the corresponding direct-connected voltage regulating branch must be closed, and then the on-off switch of the corresponding non-direct-connected branch must be disconnected, thus completing one gear switch.

[0026] Therefore, the technical solution of the present invention is not unique in the connection mode, as long as each voltage regulating branch satisfies the direct connection and indirect connection alternating mode, the same technical effect can be achieved. The above two connection modes can be regarded as two preferred implementation modes under the same invention.

[0027] Therefore, when the transformer designed by the present invention is used, the transition switch unit switch is opened or closed once each time the gear is switched. The transition switch unit switch is opened and closed once when the gear is switched twice in succession. However, in the prior art, the vacuum interrupter of the main circuit transition circuit is opened and closed once each time the gear is switched.

[0028] It can be concluded that, compared with the prior art, the technical solution can reduce the opening and closing times of the vacuum interrupter by half under the premise of the same voltage regulation times. On the other hand, the technical solution of the present invention can always allow the voltage regulation branch of the previous gear to provide a transition voltage for the voltage regulation branch of the adjacent gear, so that the transition voltage can always change with the different voltage regulation gears.

[0029] In addition to the positive voltage regulation and reverse voltage regulation operations, there is also switching from positive voltage regulation to reverse voltage regulation, or from reverse voltage regulation to positive voltage regulation. During the switching process, the polarity conversion switch must be switched from the upper end to the lower end, or from the lower end to the upper end. During the switching process, each voltage regulation branch must be in a disconnected state and cannot provide a transition voltage for the voltage regulation circuit.

[0030] The rated voltage branch bypasses the polarity conversion switch and is directly connected between the main winding tap and the output end of the voltage regulation circuit. When the on-off switch of the rated voltage branch is closed, the rated voltage branch is in the on state, which can ensure that the circuit does not interrupt the voltage supply when switching between positive and negative voltage regulation.

[0031] Preferably, the transition switching unit is composed of a transition resistor and an on-off switch in parallel, the first input terminal of the transition switching unit is connected to the first end of the transition resistor and the first end of the on-off switch, the second input terminal of the transition switching unit also serves as the output terminal of the transition switching unit, and the output terminal of the transition switching unit is connected to the second end of the transition resistor and the second end of the on-off switch.

[0032] Preferably, the transition switching unit on-off switch adopts a vacuum interrupter.

[0033] Preferably, the on-off switches connected in series on the voltage regulating branch and the rated voltage branch all adopt vacuum interrupters.

[0034] As another option, a second vacuum interrupter is connected in series on the line from the second input terminal to the output terminal in the transition switching unit, and a third vacuum interrupter is connected in series on the line from the first input terminal to the output terminal via the transition resistor, and at the same time, the on-off switches connected in series on the voltage regulating branch and the rated voltage branch are both ordinary on-off switches.

[0035] In summary, the transformer designed according to the technical solution of the present invention has the advantages of long service life, small voltage fluctuation during transformation, high output voltage quality, halving the number of voltage regulating windings at the same gear, and low manufacturing cost.

[0036] In the present invention, the input terminal and the output terminal are defined to clearly describe the connection relationship between the various components of the circuit, wherein "input" and "output" are only used to distinguish different connection terminals and do not represent the flow or transmission direction of current or signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is an on-load voltage regulation circuit of a nine-speed transformer;

[0038] Figure 2 It is an on-load voltage regulation circuit of a nine-speed transformer with another connection method. DETAILED DESCRIPTION

[0039] The structural features and working principle of the nine-speed transformer voltage regulating circuit with polarity conversion described in the present invention are further described below in conjunction with the accompanying drawings.

[0040] See also Figure 1 The figure shows a principle diagram of a nine-speed transformer voltage regulating circuit under the technical solution of the present invention, which consists of a main winding, a voltage regulating winding, a rated voltage branch, a transition switching unit, and five voltage regulating branches.

[0041] The transition switching unit comprises a first input terminal T1, a second input terminal T2, an output terminal Xb, and a vacuum interrupter D0 connected in series between the first input terminal T1 and the output terminal Xb and a transition resistor R in parallel.

[0042] The first voltage regulating coil L1, the second voltage regulating coil L2, the third voltage regulating coil L3 and the fourth voltage regulating coil L4 are connected end to end to form a voltage regulating winding, and a winding tap is provided at each end of the voltage regulating coil, wherein adjacent voltage regulating coils share one winding tap, and the four voltage regulating coils are provided with a total of five voltage regulating winding taps, namely, an upper end tap X1, a middle upper end tap X2, a middle end tap X3, a middle lower end tap X4 and a lower end tap X5.

[0043] The common contact of the polarity conversion switch KaKb is connected to the tap Xa of the main winding output end, and the two independent contacts of the polarity conversion switch are respectively connected to the upper tap X1 and the lower tap X5 of the voltage regulating winding.

[0044] On-off switch D1, on-off switch D2, on-off switch D3, on-off switch D4, on-off switch D5 and on-off switch Ke are all vacuum interrupters.

[0045] One end of the on-off switch D1 is connected to the upper tap X1, and the other end is connected to the second input end T1 of the transition switching unit, and exists as a voltage regulating branch.

[0046] One end of the on-off switch D2 is connected to the middle upper tap X2, and the other end is connected to the first input terminal T1 of the transition switching unit, and is connected to the output terminal Xb of the voltage regulating circuit through the parallel structure of the vacuum interrupter D0 and the resistor R, existing as a voltage regulating branch.

[0047] One end of the on-off switch D3 is connected to the middle tap X3, and the other end is connected to the second input end T2 of the transition switching unit, and exists as a voltage regulating branch.

[0048] One end of the on-off switch D4 is connected to the middle and lower tap X4, and the other end is connected to the first input terminal T1 of the transition switching unit, and is connected to the output terminal Xb of the voltage regulating circuit through the parallel structure of the vacuum interrupter D0 and the resistor R, and exists as a voltage regulating branch.

[0049] One end of the on-off switch D5 is connected to the lower tap X5, and the other end is connected to the first input terminal T1 of the transition switching unit, and is connected to the output terminal Xb of the voltage regulating circuit through the parallel structure of the vacuum interrupter D0 and the resistor R, and exists as a voltage regulating branch.

[0050] The correspondence between the combination status of the polarity switch, each on-off switch and each gear position of the voltage regulation circuit is as follows:

[0051] 1st gear: Ka closes D5, D0 opens the voltage regulating windings L1, L2, L3, L4 are connected to the circuit

[0052] 2nd gear: Ka is on, D4 is on, D0 is on, and the voltage regulating windings L1, L2, and L3 are connected to the circuit.

[0053] 3rd gear: Ka closes D3, closes D0, and opens the voltage regulating windings L1 and L2, which are connected to the circuit

[0054] 4th gear: Ka is on, D2 is on, D0 is on, and the voltage regulating winding L1 is connected to the circuit

[0055] 5th gear: Ka, D1, D0, L1, L2, L3, L4 are not connected to the circuit

[0056] 5th gear: Kb is on, D5 is on, D0 is open, and the voltage regulating windings L1, L2, L3, and L4 are not connected to the circuit

[0057] 6th gear: Kb is on, D4 is on, D0 is on, and the voltage regulating winding L1 is reversely connected to the circuit

[0058] 7th gear: Kb is closed, D3 is closed, D0 is opened, and the voltage regulating winding L2 and L1 are reversely connected to the circuit

[0059] 8th gear: Kb is on, D2 is on, D0 is on, and the voltage regulating winding L3, L2, and L1 are reversely connected to the circuit

[0060] 9th gear: Kb closes D1 closes D0 and opens the voltage regulating winding L4, L3, L2, L1 reversely connected to the circuit

[0061] Note: Ka means that the Ka terminal of the polarity switch is in the on state, and Kb means that the Kb terminal of the bidirectional switch is in the on state.

[0062] Voltage regulation principle:

[0063] When the voltage regulating circuit is in gear 1, the Ka terminal of the polarity switch is in the on state, the on-off switch D5 is in the closed state, the vacuum interrupter D0 of the transition switching unit is in the off state, and the voltage regulating windings L1, L2, L3, and L4 are all connected to the circuit.

[0064] Close the on-off switch D4. At this time, the on-off switch D4 and the on-off switch D5 are in the closed state at the same time, and the transition resistor provides short-circuit protection. Then open the on-off switch D5, close the transition switching unit vacuum interrupter D0, and the voltage regulating windings L1, L2, and L3 are connected to the circuit. The circuit completes the switch from gear 1 to gear 2.

[0065] First, disconnect the vacuum interrupter D0 of the transition switching unit, and then close the on-off switch D3. At this time, the on-off switch D4 and the on-off switch D3 are both in the closed state, the two branches are connected to each other, and the transition resistor R protects the circuit from short circuit. Then disconnect the on-off switch D4, and the voltage regulating windings L1 and L2 are connected to the circuit. The voltage regulating circuit completes the switch from gear 2 to gear 3.

[0066] Close the on-off switch D2. At this time, the on-off switch D2 and the on-off switch D3 are in the closed state at the same time, and the transition resistor provides short-circuit protection. Then open the on-off switch D3, close the transition switching unit vacuum interrupter D0, and the voltage regulating winding L1 is connected to the circuit. The circuit completes the switch from gear 3 to gear 4.

[0067] First, disconnect the vacuum interrupter D0 of the transition switching unit, and then close the on-off switch D1. At this time, the on-off switch D1 and the on-off switch D2 are both in the closed state, and the transition resistor R provides short-circuit protection. Then disconnect the on-off switch D2, and the voltage regulating windings L1, L2, L3, and L4 are not connected to the circuit. The voltage regulating circuit completes the switch from the 4th gear to the 5th gear.

[0068] After the positive voltage regulation is completed, it is necessary to switch from positive voltage regulation to reverse voltage regulation. First, close the on-off switch Ke, the rated voltage branch is in the on state, and then disconnect the on-off switch D1. At this time, the circuit is supplied with voltage from the rated voltage branch, and the polarity switches KaKb are in a non-powered state. Then turn the polarity switch, switching from the Ka end to the Kb end. Then close the on-off switch D5 and disconnect the on-off switch Ke. At this time, the circuit is still in gear 5, completing the switch from positive voltage regulation to reverse voltage regulation.

[0069] Close the on-off switch D4, then open the on-off switch D5, and then close the transition switching unit vacuum interrupter D0. At this time, the voltage regulating winding L4 is reversely connected to the circuit, and the voltage regulating circuit completes the switch from gear 5 to gear 6.

[0070] First, disconnect the vacuum interrupter D0 of the transition switching unit, then close the on-off switch D3, and then disconnect the on-off switch D4. At this time, the voltage regulating windings L4 and L3 are reversely connected to the circuit, and the voltage regulating circuit completes the switch from the 6th gear to the 7th gear.

[0071] Close the on-off switch D2, then open the on-off switch D3, and then close the transition switching unit vacuum interrupter D0. At this time, the voltage regulating windings L4, L3, and L2 are reversely connected to the circuit, and the voltage regulating circuit completes the switch from 7th gear to 8th gear.

[0072] First, disconnect the vacuum interrupter D0 of the transition switching unit, then close the on-off switch D1, and then disconnect the on-off switch D2. At this time, the voltage regulating windings L4, L3, L2, and L1 are all reversely connected to the circuit, and the voltage regulating winding completes the switching from gear 8 to gear 9.

[0073] In the entire nine-speed voltage regulation process, the gears are switched eight times. If the main circuit transition circuit structure used in the background technology is applied, the vacuum interrupters in the main circuit and the transition circuit need to be opened and closed eight times respectively. However, by applying the technical solution of the present invention, the vacuum interrupter of the transition switching unit, the electronic component with the highest switching frequency in the circuit, only needs to be opened and closed four times, which saves half of the switching times compared with the prior art.

[0074] In the positive voltage regulation process or the reverse voltage regulation process, the branch of the previous gear just provides the transition voltage for the branch of the next gear, which ensures that in the specific voltage regulation process, there will be different transition voltages according to different voltage regulation gears. Therefore, according to the technical solution of the present invention, the corresponding nine-gear transformer has the advantages of small voltage regulation fluctuation and high voltage stability.

[0075] This technical solution applies the positive and negative voltage regulation methods to the nine-speed transformer voltage regulation circuit, which reduces the number of voltage regulation windings to four stages compared to the existing technology, effectively reducing the manufacturing cost.

[0076] See also Figure 2 Shown is a schematic diagram of a nine-speed transformer voltage regulation circuit under the technical solution in this aspect, which consists of a main winding, a voltage regulating winding, a rated voltage branch, a transition switching unit, and five voltage regulating branches.

[0077] The transition switching unit comprises a first input terminal T1, a second input terminal T2, an output terminal Xb, and a vacuum interrupter D0 connected in series between the first input terminal T1 and the output terminal Xb and a transition resistor R in parallel.

[0078] The first voltage regulating coil L1, the second voltage regulating coil L2, the third voltage regulating coil L3 and the fourth voltage regulating coil L4 are connected end to end to form a voltage regulating winding, and a voltage regulating winding tap is provided at each end of the voltage regulating coil, wherein adjacent voltage regulating coil ends share a voltage regulating winding tap, and the four voltage regulating coils are provided with a total of five voltage regulating winding taps, namely, an upper end tap X1, a middle upper end tap X2, a middle end tap X3, a middle lower end tap X4 and a lower end tap X5.

[0079] The common contact of the polarity conversion switch KaKb is connected to the tap Xa of the main winding output end, and the two independent contacts of the polarity conversion switch are respectively connected to the upper tap X1 and the lower tap X5 of the voltage regulating winding.

[0080] On-off switch D1, on-off switch D2, on-off switch D3, on-off switch D4, on-off switch D5 and on-off switch Ke are all vacuum interrupters.

[0081] One end of the on-off switch D1 is connected to the upper tap X1, and the other end is connected to the first input terminal T1 of the transition switching unit, and is connected to the output terminal Xb of the voltage regulating circuit through the parallel structure of the vacuum interrupter D0 and the resistor R, and exists as a voltage regulating branch.

[0082] One end of the on-off switch D2 is connected to the middle upper tap X2, and the other end is connected to the second input end T2 of the transition switching unit, and exists as a voltage regulating branch.

[0083] One end of the on-off switch D3 is connected to the middle tap X3, and the other end is connected to the first input end T1 of the transition switching unit, and is connected to the output end Xb of the voltage regulating circuit through the parallel structure of the vacuum interrupter D0 and the resistor R, existing as a voltage regulating branch.

[0084] One end of the on-off switch D4 is connected to the middle and lower tap X4, and the other end is connected to the second input end T2 of the transition switching unit, and exists as a voltage regulating branch.

[0085] One end of the on-off switch D5 is connected to the lower tap X5, and the other end is connected to the first input terminal T1 of the transition switching unit, and is connected to the output terminal Xb of the voltage regulating circuit through the parallel structure of the vacuum interrupter D0 and the resistor R, and exists as a voltage regulating branch.

[0086] The correspondence between the combination status of the polarity switch, each on-off switch and each gear position of the voltage regulation circuit is as follows:

[0087] 1st gear: Ka is on, D5 is on, D0 is on, and the voltage regulating windings L1, L2, L3, and L4 are connected to the circuit

[0088] 2nd gear: Ka closes D4, closes D0, and opens the voltage regulating windings L1, L2, and L3, which are connected to the circuit

[0089] 3rd gear: Ka is on, D3 is on, D0 is on, and the voltage regulating windings L1 and L2 are connected to the circuit

[0090] 4th gear: Ka closes D2, closes D0, opens the voltage regulating winding L1, and connects to the circuit

[0091] 5th gear: Ka is on, D1 is on, D0 is on, and the voltage regulating windings L1, L2, L3, and L4 are not connected to the circuit

[0092] 5th gear: Kb is on, D5 is on, D0 is on, and the voltage regulating windings L1, L2, L3, and L4 are not connected to the circuit

[0093] 6th gear: Kb is closed, D4 is closed, D0 is open, and the voltage regulating winding L4 is reversely connected to the circuit

[0094] 7th gear: Kb is on, D3 is on, D0 is on, and the voltage regulating windings L4 and L3 are reversely connected to the circuit

[0095] 8th gear: Kb is closed, D2 is closed, D0 is open, and the voltage regulating winding L4, L3, and L2 are reversely connected to the circuit

[0096] 9th gear: Kb, D1, D0, and voltage regulating windings L4, L3, L2, and L1 are reversely connected to the circuit

[0097] Note: Ka means the Ka end of the polarity switch is in the on state, and Kb means the Kb end of the bidirectional switch is in the on state. Voltage regulation principle:

[0098] When the voltage regulating circuit is in gear 1, the Ka terminal of the polarity switch is in the on state. The on-off switch D5 is in the on state, the vacuum interrupter D0 of the transition switching unit is in the on state, and the voltage regulating windings L1, L2, L3, and L4 are all connected to the circuit.

[0099] First, disconnect the vacuum interrupter D0 of the transition switching unit, and then close the on-off switch D4. At this time, the on-off switch D4 and the on-off switch D5 are both in the closed state, the two branches are connected to each other, and the transition resistor R protects the circuit from short circuit. Then disconnect the on-off switch D5, and the voltage regulating windings L1, L2, and L3 are connected to the circuit. The voltage regulating circuit completes the switch from gear 1 to gear 2.

[0100] Close the on-off switch D3. At this time, the on-off switch D4 and the on-off switch D3 are in the closed state at the same time, and the transition resistor R provides short-circuit protection. Then the on-off switch D4 is opened, and the transition switching unit vacuum interrupter D0 is closed. At this time, the voltage regulating windings L1 and L2 are connected to the circuit. The circuit completes the switch from gear 2 to gear 3.

[0101] First, disconnect the transition switching unit vacuum interrupter D0, and then close the on-off switch D2. At this time, the on-off switch D2 and the on-off switch D3 are both in the closed state, and the transition resistor R provides short-circuit protection. Then disconnect the on-off switch D3, and the voltage regulating winding L1 is connected to the circuit. The voltage regulating circuit completes the switch from gear 3 to gear 4.

[0102] Close the on-off switch D1. At this time, the on-off switches D1 and D2 are both in the closed state, and the transition resistor R provides short-circuit protection. Then open the on-off switch D2 and close the transition switching unit vacuum interrupter D0. At this time, the voltage regulating windings L1, L2, L3, and L4 are not connected to the circuit. The circuit completes the switch from gear 4 to gear 5.

[0103] After the positive voltage regulation is completed, it is necessary to switch from positive voltage regulation to reverse voltage regulation. First, close the on-off switch Ke, the rated voltage branch is in the on state, and then disconnect the on-off switch D1. At this time, the circuit is supplied with voltage from the rated voltage branch, and the polarity switches KaKb are in a non-powered state. Then turn the polarity switch, switching from the Ka end to the Kb end. Then close the on-off switch D5 and disconnect the on-off switch Ke. At this time, the circuit is still in gear 5, completing the switch from positive voltage regulation to reverse voltage regulation.

[0104] First, disconnect the transition switching unit vacuum interrupter D0, and then close the on-off switch D4. At this time, the on-off switch D4 and the on-off switch D5 are both in the closed state, and the transition resistor R provides short-circuit protection. Then disconnect the on-off switch D5, and the voltage regulating winding L4 is reversely connected to the circuit. The voltage regulating circuit completes the switch from the 5th gear to the 6th gear.

[0105] Close the on-off switch D3, then open the on-off switch D4, and then close the transition switching unit vacuum interrupter D0. At this time, the voltage regulating windings L4 and L3 are reversely connected to the circuit, and the voltage regulating circuit completes the switch from gear 6 to gear 7.

[0106] First, disconnect the vacuum interrupter D0 of the transition switching unit, then close the on-off switch D2, and then disconnect the on-off switch D3. At this time, the voltage regulating windings L4, L3, and L2 are reversely connected to the circuit, and the voltage regulating circuit completes the switching from 7th gear to 8th gear.

[0107] Close the on-off switch D1, then open the on-off switch D2, and then close the transition switching unit vacuum interrupter D0. At this time, the voltage regulating windings L4, L3, L2, and L1 are all reversely connected to the circuit, and the voltage regulating circuit completes the switch from gear 8 to gear 0.

[0108] Figure 1 , Figure 2 Although the connection methods of the other ends of the four voltage regulating branches in the circuit are different, they are essentially just changes in order. Although the corresponding relationship between the combination state of the on-off switch, the polarity switch and the vacuum interrupter in the transition switching unit and the various gears of the transformer is different, the principles are the same. The two have the same beneficial effects and are two different preferred implementations under the same technical solution.

Claims

1. A staggered parallel nine-speed transformer on-load voltage regulation circuit with polarity conversion, comprising a main winding, a polarity conversion switch, a voltage regulating winding, a transition switching unit, a rated voltage branch, and five voltage regulating branches; The voltage regulating winding is composed of four sections of voltage regulating coils wound in the same direction and connected end to end in sequence. The voltage regulating winding includes two end taps and three middle taps. The tap at the input end of the main winding is connected to the input end of the voltage regulating circuit, and the tap at the output end of the main winding is connected to the common contact of the polarity conversion switch; the two independent contacts of the polarity conversion switch are respectively connected to the two end taps of the voltage regulating winding; The transition switching unit is composed of a transition resistor and an on-off switch connected in parallel, and the two ends of the parallel structure are the first input end and the second input end of the transition switching unit, and the second input end also serves as the output end of the voltage regulating circuit; Each voltage regulating branch is connected in series with an on-off switch, one end of which is connected to the two end taps and the middle tap of the voltage regulating coil respectively; the other end is connected in parallel in two groups adjacent to each other and connected to the two input ends of the transition switching unit respectively; An on-off switch is connected in series on the rated voltage branch, one end of the rated voltage branch is connected to the output end of the main winding; the other end is connected to any end of the transition switching unit; The transition switching unit on-off switch adopts a vacuum interrupter; The on-off switches connected in series on the voltage regulating branch and the rated voltage branch both adopt vacuum interrupters.

2. A staggered parallel nine-speed transformer on-load voltage regulation circuit with polarity conversion according to claim 1, characterized in that: The other end of the rated voltage branch is connected to the output end of the voltage regulating circuit.

3. The staggered parallel nine-speed transformer on-load voltage regulation circuit with polarity conversion according to claim 1, characterized in that: The other ends of the voltage regulating branch connected to the upper tap, the voltage regulating branch connected to the middle tap, and the voltage regulating branch connected to the lower tap are directly connected to the second input end of the transition switching unit; the other ends of the voltage regulating branch connected to the middle-upper tap and the voltage regulating branch connected to the middle-lower tap are connected to the first input end of the transition switching unit.

4. The staggered parallel nine-speed transformer on-load voltage regulation circuit with polarity conversion according to claim 1 is characterized in that: The voltage regulating branch connected to the upper tap, the voltage regulating branch connected to the middle tap, and the voltage regulating branch connected to the lower tap, the other ends of the three voltage regulating branches are connected to the first input end of the transition switching unit; the voltage regulating branch connected to the middle-upper tap and the voltage regulating branch connected to the middle-lower tap, the other ends of the two voltage regulating branches are connected to the second input end of the transition switching unit.

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