Voltage regulating structure of no-load split transformer

Abstract

The application relates to a no-field split transformer voltage regulating structure, wherein a first high-voltage coil and a second high-voltage coil are first connected in parallel and then connected in series with a first voltage regulating coil, the first high-voltage coil, the second high-voltage coil and the first voltage regulating coil are all connected with a static contact E of a regulating switch, the tail end of the first voltage regulating coil and the head end of a second voltage regulating coil are connected in series and are both connected with a static contact C of the regulating switch, the tail end of the second voltage regulating coil is connected with a static contact A of the regulating switch, a third high-voltage coil and a fourth high-voltage coil are first connected in parallel and then connected in series with a third voltage regulating coil, the third high-voltage coil, the fourth high-voltage coil and the third voltage regulating coil are all connected with a static contact F of the regulating switch, the head end of the third voltage regulating coil and the tail end of a fourth voltage regulating coil are connected in series and are both connected with a static contact D of the regulating switch, and the head end of the fourth voltage regulating coil is connected with a static contact B of the regulating switch. The application fundamentally solves the problems of local overheating, excessive loss and insufficient short-circuit resistance caused by internal circulation of the existing structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of transformer, in particular to a no-field split transformer voltage regulating structure. BACKGROUND

[0002] In order to improve the short-circuit resistance of the transformer, almost all the high-voltage power plant transformers in power plants currently adopt the upper and lower split transformer structure. The transformer structure is compact, two low-voltage coils are distributed in the vertical direction (axial direction) on the inside, the high-voltage coil is arranged on the outside corresponding to the low-voltage coil, that is, also distributed in the upper and lower directions, the high-voltage coil is connected in series with the regulating coil in the middle, the upper and lower high-voltage coils are connected in parallel, and the regulating coils in the upper and lower parts are connected to the regulating switch in parallel, so that the two regulating coils can be switched synchronously, and then the number of turns of the regulating coil connected is adjusted by adjusting the gear of the regulating switch, so as to realize the purpose of adjusting the output voltage of the transformer.

[0003] When the transformer is in full through operation, that is, both of the two low-voltage coils on the inside are in the running state, and the corresponding upper and lower high-voltage coils on the outside are also in the running state at the same time. In this running state, all the coils are in a symmetrical magnetic leakage field environment, and the induced current is also symmetrically distributed in the upper and lower directions. At this time, it is in a safe running state.

[0004] However, when the transformer is in half through operation, that is, only one of the two low-voltage coils on the inside is in the running state, and the other low-voltage coil is in the non-running state, and there is no current flowing through the low-voltage coil in the non-running state. The corresponding high-voltage coil in the corresponding branch on the outside is also in the non-running state. Since the regulating part of the high-voltage coil is connected in parallel at this time, the two branches connected in parallel are in an upper and lower asymmetric magnetic leakage field, and the two loops pass through different magnetic leakage fluxes, respectively, which will induce an internal circulating current between the two loops. The size of the circulating current is about 1.5-2 times the normal current. If not handled properly, it will cause long-term operation hazards such as local overheating and excessive loss. In severe cases, it will lead to insufficient short-circuit resistance. According to the actual operation situation, most of the short-circuit accidents in the field occur at this place, which becomes the "short board" of the entire power supply system, and brings great hidden dangers to the safe operation of the power system.

[0005] In the past practice, in order to eliminate the hidden danger at this place, the method of increasing the cross-sectional area of the regulating part of the wire is often used, that is, using wires of different specifications from the high-voltage main coil, and increasing the stress level of the wires at this place to improve the short-circuit resistance. However, this method only addresses the symptoms by artificially increasing the wire specifications, which may alleviate the problem to some extent, but does not fundamentally solve the problem. It is a temporary solution rather than a permanent one. Such treatment will lead to increased material consumption, larger overall size of the transformer, complex coil and lead design, and difficult production and manufacturing problems. SUMMARY

[0006] The present application aims at providing a no-field split transformer voltage regulating structure, which fundamentally solves the problems of local overheating, excessive loss and insufficient short-circuit resistance caused by internal circulation between existing structure circuits.

[0007] The present application aims at providing a no-field split transformer voltage regulating structure, which fundamentally solves the problems of local overheating, excessive loss and insufficient short-circuit resistance caused by internal circulation between existing structure circuits.

[0008] The present application aims at providing a no-field split transformer voltage regulating structure, which fundamentally solves the problems of local overheating, excessive loss and insufficient short-circuit resistance caused by internal circulation between existing structure circuits.

[0009] The first parallel line is connected with the static contact E of the regulating switch through a first connecting line.

[0010] The first regulating coil tail end is connected with the second regulating coil head end through a first series line, and the first series line is connected with the static contact C of the regulating switch through a second connecting line.

[0011] The second regulating coil tail end is connected with the static contact A of the regulating switch through a third connecting line.

[0012] The third parallel line is connected with the static contact F of the regulating switch through a fourth connecting line.

[0013] The third regulating coil head end is connected with the fourth regulating coil tail end through a second series line, and the second series line is connected with the static contact D of the regulating switch through a fifth connecting line.

[0014] The fourth regulating coil head end is connected with the static contact B of the regulating switch through a sixth connecting line.

[0015] Adjacent stationary contacts are connected by rotating moving contacts. When stationary contacts A and B are connected, it is position 1, and all voltage regulating coils are connected. When stationary contacts B and C are connected, it is position 2, and the first, fourth, and third voltage regulating coils are connected in series. When stationary contacts C and D are connected, it is position 3, and the first and third voltage regulating coils are connected in series. When stationary contacts D and E are connected, it is position 4, and the third voltage regulating coil is connected. When stationary contacts E and F are connected, it is position 5, and all voltage regulating coils are not connected.

[0016] The advantages and positive effects of this invention are as follows:

[0017] 1. The high-voltage coil of this invention still adopts an upper and lower parallel structure to ensure that the overall performance of the transformer remains unchanged during semi-pass-through operation, that is, to maintain the original semi-pass-through short-circuit impedance to ensure that the overall short-circuit withstand level of the transformer remains unchanged. However, all voltage regulating coils are connected in series in all tap positions. This ensures that even if the voltage regulating coils are in an asymmetrical leakage magnetic field, no circulating current problem will occur. Regardless of normal operation or fault conditions, the current flowing through the several voltage regulating coils is only the rated value, and there is no superposition of circulating currents. This avoids problems such as increased losses, increased temperature rise, and poor short-circuit capability caused by circulating currents.

[0018] 2. The capacity of a transformer in half-crossing operation is about half that in full-crossing operation. Using the voltage regulation structure of this invention, the current flowing through its voltage regulation coil is also about half that in full-crossing operation, which means that its short-circuit current density is only half that in full-crossing operation, that is, the short-circuit withstand capability is doubled.

[0019] 3. This invention includes multiple taps, which allows each voltage regulating coil to be connected in an orderly and symmetrical manner during the semi-crossing operation of the transformer, ensuring optimal leakage flux balance and further improving the ability to resist short-circuit faults.

[0020] 4. When the transformer is operating at the minimum number of turns, the structure of this invention can be in a completely disconnected state, that is, there is no current flowing in the circuit, the current in the voltage regulating coil is 0, the resistance loss is 0, and the energy saving performance of the transformer is increased by about 10%.

[0021] 5. This invention solves the problem of increased actual operating current caused by circulating current. It eliminates the need to increase the cross-sectional area of ​​the voltage regulating conductor, thereby reducing the required conductor cross-sectional area and weight, directly reducing the amount of copper used, and indirectly reducing the amount of other materials such as silicon steel and insulating oil used.

[0022] 6、The present application is convenient for technical transformation, only the original high-voltage coil needs to be replaced, and other components such as low-voltage coil, switch, iron core, oil tank and the like can remain unchanged, which can directly improve the operation energy efficiency index and safety of the product, and indirectly improve the social and economic benefits of the existing product by prolonging the service life of the existing product. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic diagram of the present application,

[0024] Figure 2 is a schematic diagram of the use state of the present application Figure 1 ,

[0025] Figure 3 is a schematic diagram of the use state of the present application Figure 2 ,

[0026] Figure 4 is a schematic diagram of the use state of the present application Figure 3 ,

[0027] Figure 4 is a schematic diagram of the use state of the present application Figure 6 ,

[0028] Figure 5 is a schematic diagram of the use state of the present application Figures 1-6 .

[0029] Among them, 1 is an adjusting switch, 2 is a static contact A, 3 is a static contact B, 4 is a static contact C, 5 is a static contact D, 6 is a static contact E, 7 is a static contact F, 8 is a moving contact, 9 is a first series circuit, 10 is a second parallel circuit, 11 is a second voltage regulating coil, 12 is a third voltage regulating coil, 13 is a first high-voltage coil, 14 is a third high-voltage coil, 15 is a first connecting line, 16 is a second connecting line, 17 is a third connecting line, 18 is a fourth connecting line, 19 is a second series circuit, 20 is a fifth connecting line, 21 is a first voltage regulating coil, 22 is a fourth voltage regulating coil, 23 is a second high-voltage coil, 24 is a fourth high-voltage coil, 25 is a sixth connecting line, and 26 is a first parallel circuit. DETAILED DESCRIPTION

[0030] The present application will be further described in detail below in combination with the drawings.

[0031] As shown in Figure 1 , the present application comprises an adjusting switch 1, a plurality of high-voltage coils and a plurality of voltage regulating coils, wherein the adjusting switch 1 comprises a moving contact 8 and a plurality of static contacts.

[0032] As shown in Figure 1As shown in the figure, the first high-voltage coil 13 and the second high-voltage coil 23 are first connected in parallel, wherein one end of the first high-voltage coil 13 and the second high-voltage coil 23 is connected to the head end point A, and the other end is connected in parallel through the first parallel line 26, then the first high-voltage coil 13 and the second high-voltage coil 23 are connected in series with the first end of the first voltage regulating coil 21, and the first parallel line 26 is connected with the static contact E6 of the adjusting switch 1 through the first connecting line 15, that is, the first end of the first high-voltage coil 13, the second high-voltage coil 23 and the first voltage regulating coil 21 are connected with the static contact E6, and the tail end of the first voltage regulating coil 21 is connected in series with the first end of the second voltage regulating coil 11 through the first series line 9, and the first series line 9 is connected with the static contact C4 of the adjusting switch 1 through the second connecting line 16, that is, the tail end of the first voltage regulating coil 21 and the first end of the second voltage regulating coil 11 are connected with the static contact C4, and the tail end of the second voltage regulating coil 11 is connected with the static contact A2 of the adjusting switch 1 through the third connecting line 17.

[0033] As shown in the figure, Figures 2-6 The third high-voltage coil 14 and the fourth high-voltage coil 24 are first connected in parallel, wherein one end of the third high-voltage coil 14 and the fourth high-voltage coil 24 is connected to the tail end point X, and the other end is connected in parallel through the second parallel line 10, then the third high-voltage coil 14 and the fourth high-voltage coil 24 are connected in series with the tail end of the third voltage regulating coil 12, and the second parallel line 10 is connected with the static contact F7 of the adjusting switch 1 through the fourth connecting line 18, that is, the tail end of the third high-voltage coil 14, the fourth high-voltage coil 24 and the third voltage regulating coil 12 are connected with the static contact F7, and the first end of the third voltage regulating coil 12 is connected in series with the tail end of the fourth voltage regulating coil 22 through the second series line 19, and the second series line 19 is connected with the static contact D5 of the adjusting switch 1 through the fifth connecting line 20, that is, the first end of the third voltage regulating coil 12 and the tail end of the fourth voltage regulating coil 22 are connected with the static contact D5, and the first end of the fourth voltage regulating coil 22 is connected with the static contact B3 of the adjusting switch 1 through the sixth connecting line 25.

[0034] As shown in the figure, Figures 2-6 The present application can realize the connection of different voltage regulating coils by moving the moving contact 8 on the adjusting switch 1 to realize the connection of different static contacts, so as to achieve the purpose of adjusting voltage.

[0035] The working principle of the present application is as follows:

[0036] As shown in the figure, Figures 2-6As shown, when the transformer is in half-cross operation, that is, only one of the two low-voltage coils on the inside (a1, x1 and a2, x2 are connected respectively) is in operation, and the other low-voltage coil is in non-operation, no current flows in the non-operating low-voltage coil, and the corresponding high-voltage coil of the branch on the outside is also in non-operation, and because the voltage regulating part in the high-voltage coil in the prior art is connected in parallel, the two branches in parallel are in an upper and lower asymmetric magnetic leakage field, and different leakage fluxes pass through the two loops respectively, which causes an internal circulating current between the two loops, and the size of the circulating current is about 1.5-2 times the normal current, and if not handled properly, it will cause long-term operation hazards such as local overheating and excessive loss, and in severe cases, it will cause insufficient short-circuit resistance.

[0037] As shown in Figures 1-6 , the high-voltage coil of the present application still adopts an upper and lower parallel structure, ensuring that the overall performance of the transformer in half-cross operation remains unchanged, that is, maintaining the original half-cross short-circuit impedance to ensure that the overall short-circuit resistance of the transformer remains unchanged, but the voltage regulating position of the upper and lower high-voltage coils of the present application is respectively provided with four voltage regulating windings (first voltage regulating coil 21, second voltage regulating coil 11, third voltage regulating coil 12, fourth voltage regulating coil 22), and one voltage regulating winding in the high-voltage coil of each branch will be directly connected with the main coil of this part, that is, the first voltage regulating coil 21 is connected with the first high-voltage coil 13 and the second high-voltage coil 23, and the third voltage regulating coil 12 is connected with the third high-voltage coil 14 and the fourth high-voltage coil 24, and the other voltage regulating winding (second voltage regulating coil 11 and fourth voltage regulating coil 22) is connected with the main coil of the other branch through adjusting switch 1, and each voltage regulating coil is connected in single-branch series, which fundamentally solves the problem of circulating current.

[0038] As shown in Figure 2 , the present application has a total of 5 gears for adjustment:

[0039] Gear 1: As shown in Figure 3 , the static contact A2 and the static contact B3 are connected, and all voltage regulating coils are connected, specifically: the first high-voltage coil 13 / second high-voltage coil 23, the first voltage regulating coil 21, the second voltage regulating coil 11, the fourth voltage regulating coil 22, the third voltage regulating coil 12, the third high-voltage coil 14 / fourth high-voltage coil 24 are connected in series.

[0040] Gear 2: As shown in Figure 4 , the static contact B3 and the static contact C4 are connected, specifically: the first high-voltage coil 13 / second high-voltage coil 23, the first voltage regulating coil 21 (connected to the static contact C4 through the second connection line 16), the fourth voltage regulating coil 22, the third voltage regulating coil 12, the third high-voltage coil 14 / fourth high-voltage coil 24 are connected in series.

[0041] Gear 3: As shown in Figure 5As shown, the static contact C4 and the static contact D5 are connected, specifically: the first high-voltage coil 13 / the second high-voltage coil 23, the first voltage regulating coil 21 (connecting the static contact C4 through the second connecting line 16), the third voltage regulating coil 12 (the static contact D5 is directly connected), the third high-voltage coil 14 / the fourth high-voltage coil 24 are connected in series.

[0042] 4th gear: as shown in Figure 6 The static contact D5 and the static contact E6 are connected, specifically: the first high-voltage coil 13 / the second high-voltage coil 23 (connecting the static contact E6 through the first connecting line 15), the third voltage regulating coil 12 (the static contact D5 is directly connected), the third high-voltage coil 14 / the fourth high-voltage coil 24 are connected in series.

[0043] 5th gear: as shown in ​ The static contact E6 and the static contact F7 are connected, and the first high-voltage coil 13 / the second high-voltage coil 23 and the third high-voltage coil 14 / the fourth high-voltage coil 24 are directly connected in series.

[0044] From the above, from the 1st gear to the 5th gear, the number of voltage regulating coils connected decreases in turn, and the corresponding power grid voltage also decreases in turn.

Claims

1. A no-load split transformer voltage regulating structure, characterized by: The application relates to a voltage regulator, which comprises an adjusting switch (1), a plurality of high-voltage coils and a plurality of voltage regulating coils, wherein the adjusting switch (1) comprises a moving contact (8) and a plurality of static contacts, the first high-voltage coil (13) and the second high-voltage coil (23) are connected in parallel first, then are connected in series with the first voltage regulating coil (21) at the first end, the first high-voltage coil (13), the second high-voltage coil (23) and the first voltage regulating coil (21) at the first end are all connected with the static contact E (6) of the adjusting switch (1), the first voltage regulating coil (21) at the tail end is connected in series with the second voltage regulating coil (11) at the first end, and the first voltage regulating coil (21) at the tail end and the second voltage regulating coil (11) at the first end are all connected with the static contact C (4) of the adjusting switch (1), the second voltage regulating coil (11) at the tail end is connected with the static contact A (2) of the adjusting switch (1), the third high-voltage coil (14) and the fourth high-voltage coil (24) are connected in parallel first, then are connected in series with the third voltage regulating coil (12) at the tail end, the third high-voltage coil (14), the fourth high-voltage coil (24) and the third voltage regulating coil (12) at the tail end are all connected with the static contact F (7) of the adjusting switch (1), the third voltage regulating coil (12) at the first end is connected in series with the fourth voltage regulating coil (22) at the tail end, and the third voltage regulating coil (12) at the first end and the fourth voltage regulating coil (22) at the tail end are all connected with the static contact D (5) of the adjusting switch (1), and the fourth voltage regulating coil (22) at the first end is connected with the static contact B (3) of the adjusting switch (1).

2. The no-load split transformer voltage regulating structure according to claim 1, characterized in that: The first parallel line (26) is arranged between the first high-voltage coil (13) and the second high-voltage coil (23), and the first parallel line (26) is connected with the static contact E (6) of the adjusting switch (1) through the first connecting line (15).

3. The off-circuit regulating structure of the split transformer according to claim 1, characterized in that: The first voltage regulating coil (21) at the tail end is connected in series with the second voltage regulating coil (11) at the first end through the first series line (9), and the first series line (9) is connected with the static contact C (4) of the adjusting switch (1) through the second connecting line (16).

4. The off-circuit regulating structure of the split transformer according to claim 1, characterized in that: The second voltage regulating coil (11) at the tail end is connected with the static contact A (2) of the adjusting switch (1) through the third connecting line (17).

5. The off-circuit regulating structure of the split transformer according to claim 1, characterized in that: The second parallel line (10) is arranged between the third high-voltage coil (14) and the fourth high-voltage coil (24), and the second parallel line (10) is connected with the static contact F (7) of the adjusting switch (1) through the fourth connecting line (18).

6. The off-circuit regulating structure of the split transformer according to claim 1, characterized in that: The third voltage regulating coil (12) at the first end is connected in series with the fourth voltage regulating coil (22) at the tail end through the second series line (19), and the second series line (19) is connected with the static contact D (5) of the adjusting switch (1) through the fifth connecting line (20).

7. The off-circuit regulating structure of the split transformer according to claim 1, characterized in that: The fourth voltage regulating coil (22) at the first end is connected with the static contact B (3) of the adjusting switch (1) through the sixth connecting line (25).

8. The off-circuit regulating structure of the split transformer according to claim 1, characterized in that: Adjacent stationary contacts are connected by rotating the moving contact (8). When stationary contacts A (2) and B (3) are connected, it is at position 1, and all voltage regulating coils are connected. When stationary contacts B (3) and C (4) are connected, it is at position 2, and the first voltage regulating coil (21), the fourth voltage regulating coil (22), and the third voltage regulating coil (12) are connected in series. When stationary contacts C (4) and D (5) are connected, it is at position 3, and the first voltage regulating coil (21) and the third voltage regulating coil (12) are connected in series. When stationary contacts D (5) and E (6) are connected, it is at position 4, and the third voltage regulating coil (12) is connected. When stationary contacts E (6) and F (7) are connected, it is at position 5, and all voltage regulating coils are not connected.

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