Winding wiring structure of self-coupling step-down phase-shifting transformer

Abstract

The invention relates to the technical field of transformers, in particular to a winding wiring structure of a self-coupling step-down phase-shifting transformer, which comprises a transformer with a three-phase structure, and each phase of the transformer internally comprises a high-voltage winding, a voltage regulating winding, a common winding, a phase modulation winding, a compensation winding, a low-voltage winding and a phase modulation switch; the high-voltage winding is used for receiving high-voltage power; the voltage regulating winding is connected in series with the high-voltage winding and is used for regulating the voltage amplitude and realizing a voltage reduction function between high voltage and medium voltage; the common winding and the voltage regulating winding are connected in series to form a self-coupling connection structure, and the common winding provides a path of medium-voltage output and is combined with the phase regulating winding to realize a phase regulating function; according to the phase-shifting step-down transformer, the number of windings is small, wiring is simple, compared with a multi-transformer combined structure achieving the same function, the cost is low, occupied space is small, additional devices such as newly-added circuits and switches are not needed, the phase-shifting step-down transformer structure is greatly simplified compared with a phase-shifting step-down transformer structure of a double-transformer-body structure, the design and manufacturing difficulty is lowered, and the reliability of system operation is improved.

Description

Technical Field

[0001] The invention relates to the technical field of transformers, in particular to a winding connection structure of an auto-coupling step-down phase-shifting transformer. Background Art

[0002] The winding connection structure of the autotransformer is a special transformer configuration. Its core feature is that its winding is not two completely independent parts, but a shared part of the coil. This structure reduces the volume, weight and cost of the autotransformer compared to traditional transformers, while improving efficiency. In this transformer, a part of the winding belongs to both the high-voltage side and the low-voltage side. This part is called the common winding, and the rest is called the series winding.

[0003] Specifically, the windings of the autotransformer are arranged from the core column from the inside to the outside in order as a phase-adjusting winding, a voltage-adjusting winding, a common winding and a series winding. The series winding and the common winding are connected in series with each other, the voltage-adjusting winding is connected in series with the head end of the common winding through a voltage-adjusting on-load switch, and the phase-adjusting winding is connected in cross-series with the end of the common winding through a phase-adjusting on-load switch. This wiring structure enables the autotransformer to not only realize voltage conversion, but also adjust the phase to meet the needs of voltage and phase control in the power system;

[0004] Usually, the autocoupler step-down transformer in the power grid only changes the voltage but cannot regulate the power flow. If the phase of the voltage on both sides of the transmission line can be changed by the autocoupler step-down transformer in the power grid, it can not only control the power flow distribution of specific lines in the complex power network on the basis of the step-down function of the original transformer, but also provide a new function of closing the loop on both sides of the system. To achieve these functions, if a conventional autocoupler step-down transformer and a phase-shifting transformer are combined, not only the number of transformers is large, the wiring is complicated, and the land is increased, but also the cost is too high due to the increase in investment in related lines, switches and other primary and secondary equipment, and the operational reliability and maintainability are poor due to the complexity of the system. Therefore, a winding connection structure of an autocoupler step-down phase-shifting transformer is proposed to address the above problems. Summary of the invention

[0005] The object of the present invention is to provide a winding connection structure of an autocoupled step-down phase-shifting transformer to solve the problem that the conventional autocoupled step-down transformer and the phase-shifting transformer are combined, which not only has a large number of transformers, complex wiring, and increased space occupation, but also increases the investment in related lines, switches and other primary and secondary equipment, resulting in extremely high costs, as well as poor operating reliability and maintainability due to the complexity of the system.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A winding connection structure of an auto-coupling step-down phase-shifting transformer, comprising a three-phase transformer, wherein each phase of the transformer comprises a high-voltage winding, a voltage regulating winding, a common winding, a phase-adjusting winding, a compensation winding, a low-voltage winding and a phase-adjusting switch;

[0008] The high-voltage winding is used to receive a high-voltage power supply;

[0009] The voltage regulating winding is connected in series with the high voltage winding to adjust the voltage amplitude and realize the voltage reduction function between the high voltage and the medium voltage;

[0010] The common winding is connected in series with the voltage regulating winding to form an auto-coupling connection structure. The common winding provides a medium voltage output and realizes a phase regulation function in combination with the phase regulating winding.

[0011] The phase-adjusting winding is connected to the common winding and the voltage-adjusting winding;

[0012] The compensation winding is used to adjust the amplitude of the medium voltage output voltage to ensure the symmetry of the multi-channel medium voltage voltage;

[0013] The low voltage winding is used to provide a low voltage output;

[0014] The phase-adjusting switch is connected in series in the phase-adjusting winding and is used to switch the phase-adjusting state to achieve phase angle adjustment.

[0015] As a further optimized content of the present invention, wherein: the transformer is provided with a low-voltage winding, a voltage regulating winding, a common winding, a high-voltage winding, a phase-adjusting winding and a compensating winding on each core column, and the iron core column of each phase of the transformer is respectively provided with a high-voltage winding, a voltage regulating winding, a common winding, a phase-adjusting winding, a compensating winding and a low-voltage winding, and each winding is an independent unit.

[0016] As a further optimization of the present invention, the high-voltage winding of each phase of the transformer is connected in series with the voltage regulating winding and the common winding in sequence, and the tail ends of the three-phase series windings are connected to form a neutral point terminated at phase 0, thereby realizing a high- and medium-voltage auto-coupling structure.

[0017] As a further optimization of the present invention, the connection point between the common winding and the voltage regulating winding leads to the medium voltage line terminals LA1, LB1 and LC1; the connection point is respectively connected to the phase-regulating windings of different phases, and the phase-regulating windings are connected in series with the phase-regulating switches step by step and then connected to the compensation winding; the three phases lead to another group of medium voltage line terminals LA2, LB2 and LC2 respectively; the three-phase low voltage windings are connected in a triangle to form low voltage side line terminals a, b, c.

[0018] As a further optimization of the present invention, the high-voltage winding, the voltage regulating winding and the common winding adopt a Yad type wiring method, and the neutral point of the common winding is grounded.

[0019] As a further optimized content of the present invention, wherein: the phase-adjusting winding is designed by a segmented structure, the phase-adjusting winding supports step-by-step adjustment of the phase angle φ, and the relationship of the phase angles satisfies the following formula:

[0020]

[0021] Where V1 and V2 are the complex forms of the two medium voltage output voltages, φ is the phase angle introduced by the phase-modulated winding, and Z is the equivalent impedance, which is used to describe the magnetic coupling effect between the windings. Δφ is the fine-tuning angle in the actual phase modulation process, and H(φ) is the harmonic correction term, which is used to compensate for the high-order harmonic distortion in the phase modulation process.

[0022] As a further optimized content of the present invention, wherein: the voltage amplitude after the compensation winding is adjusted satisfies the following formula:

[0023]

[0024] Where V comp is the output voltage after compensation, γ(k)=1+k 2 It is used to describe the nonlinear amplification effect of the compensation coefficient k on the output voltage, satisfying k>0 and k≤2. η(t) is the dynamic stability coefficient, which is used for dynamic compensation control within the period T. is a periodic correction term that optimizes the dynamic response under short-term fluctuations.

[0025] As a further optimization of the present invention, the phase-adjusting switch is used to switch the connection state of the phase-adjusting winding, and by selecting different winding segments, the phase angle of the medium voltage output is dynamically adjusted to meet various power grid flow control requirements.

[0026] As a further optimization of the present invention, the transformer is designed with a modular component structure, and the voltage regulating winding, phase regulating winding and compensation winding can all be replaced and maintained independently.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. In the present invention, a single-core transformer structure is adopted, and a phase shifting function can be added to the function of a traditional auto-coupling step-down transformer to solve the needs of power flow control and medium voltage side loop closing on the line. The auto-coupling phase-shifting transformer of this structure is a single-body structure with a small number of windings and simple wiring. It is lower in cost and occupies less space than a combined structure of multiple transformers with the same function. There is no additional circuit and switch. The structure is also much simpler than the phase-shifting step-down transformer of a double-body structure, which reduces the difficulty of design and manufacturing and improves the reliability of system operation.

[0029] 2. In the present invention, by introducing a variety of optimization formulas, significant improvements in the transformer's functions such as voltage reduction, phase shifting, and compensation regulation are achieved. The introduction of winding coupling coefficients and flux leakage correction factors makes the voltage reduction process more accurate and effectively improves the voltage conversion efficiency. The phase adjustment formula is combined with harmonic correction terms and equivalent impedance compensation to achieve dynamic phase regulation of medium voltage output, thereby improving the flexibility and accuracy of power grid power distribution. The nonlinear amplification and periodic correction formula of the compensation winding is used to enhance the voltage stability of the power grid during operation and reduce the impact of short-term fluctuations on load equipment. The overall solution not only improves the functional integration of the transformer, but also improves the reliability and efficiency of power grid operation, and is suitable for power system applications under complex load conditions.

[0030] 3. In the present invention, the connection state of the phase-adjusting winding is dynamically switched by the phase-adjusting switch, thereby realizing flexible adjustment of the phase of the medium-voltage output voltage, effectively optimizing the power grid flow distribution and load balancing, and meeting the regulation and control needs of diversified power grid scenarios. At the same time, the modular component design enables the voltage-regulating winding, phase-adjusting winding and compensation winding to be independently replaced and maintained, significantly simplifying the equipment maintenance process, improving the scalability and reliability of the system, and reducing operation and maintenance costs. The overall design enhances the convenience of operation and application adaptability of the transformer, and is particularly suitable for the efficient operation and long-term stability assurance of complex power grids. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a diagram of the winding connection structure of the present invention.

[0032] In the figure: 1. High-voltage winding; 2. Voltage regulating winding; 3. Common winding; 4. Phase regulating winding; 5. Compensation winding; 6. Low-voltage winding. DETAILED DESCRIPTION

[0033] See also Figure 1 , the present invention provides a technical solution:

[0034] A winding connection structure of an auto-coupling step-down phase-shifting transformer, comprising a three-phase transformer, wherein each phase of the transformer comprises a high-voltage winding 1, a voltage regulating winding 2, a common winding 3, a phase-adjusting winding 4, a compensation winding 5, a low-voltage winding 6 and a phase-adjusting switch;

[0035] The high voltage winding 1 is used to receive the high voltage power supply;

[0036] The voltage regulating winding 2 is connected in series with the high voltage winding 1 to adjust the voltage amplitude and realize the voltage reduction function between the high voltage and the medium voltage;

[0037] The common winding 3 is connected in series with the voltage regulating winding 2 to form an auto-coupling connection structure. The common winding 3 provides a medium voltage output and realizes the phase regulation function in combination with the phase regulating winding 4.

[0038] The phase-modulating winding 4 is connected to the common winding 3 and the voltage-modulating winding 2;

[0039] The compensation winding 5 is used to adjust the amplitude of the medium voltage output voltage to ensure the symmetry of the multi-channel medium voltage voltage;

[0040] The low voltage winding 6 is used to provide a low voltage output;

[0041] The phase-adjusting switch is connected in series in the phase-adjusting winding to switch the phase-adjusting state and realize the phase angle adjustment.

[0042] As a technical solution for further implementation of this solution, the transformer is provided with a low-voltage winding 6, a voltage regulating winding 2, a common winding 3, a high-voltage winding 1, a phase-adjusting winding 4 and a compensating winding 5 on each core column. The core column of each phase of the transformer is provided with a high-voltage winding 1, a voltage regulating winding 2, a common winding 3, a phase-adjusting winding 4, a compensating winding 5 and a low-voltage winding 6, respectively. Each winding is an independent unit. By clarifying the independent setting and arrangement of each winding on the core column, the internal structure design of the transformer is simplified, and the manufacturing efficiency and modularity of the equipment are improved.

[0043] As a technical solution for further implementation of this solution, the high-voltage winding 1 of each phase of the transformer is connected in series with the voltage regulating winding 2 and the common winding 3 in sequence, and the tail ends of the three-phase series windings are connected to form a neutral point termination 0 phase, realizing the structure of high- and medium-voltage auto-coupling connection. The high- and medium-voltage auto-coupling connection structure is adopted, which reduces the use and volume of winding materials, occupies a smaller area, and reduces the manufacturing cost and operation loss of the system;

[0044] As a technical solution for further implementation of this scheme, the connection point between the common winding 3 and the voltage regulating winding 2 leads to the medium voltage line terminals LA1, LB1 and LC1; the connection point is respectively connected to the phase-adjusting winding 4 of different phases, and the phase-adjusting winding is connected to the compensation winding 5 after being connected in series with the phase-adjusting switch step by step; the three phases lead to another set of medium voltage line terminals LA2, LB2 and LC2 respectively; the three-phase low-voltage winding 6 adopts a triangle connection to form low-voltage side line terminals a, b, c. Through the combination of the common winding and the different-phase phase-adjusting winding, the phase dynamic adjustment and multi-channel medium voltage output functions are realized, which effectively meets the needs of complex power grid power flow control;

[0045] As a technical solution for further implementation of this solution, the high-voltage winding 1, the voltage regulating winding 2 and the common winding 3 adopt the Yad type wiring method, and the neutral point of the common winding 3 is grounded. The Yad type wiring method combined with the common winding grounding design improves the system's operating stability and short-circuit protection capability, and significantly improves the reliability of the equipment;

[0046] As a technical solution for further implementation of this solution, the phase-adjusting winding 4 is designed with a segmented structure, and the phase-adjusting winding supports step-by-step adjustment of the phase angle φ. The relationship between the phase angles satisfies the following formula:

[0047]

[0048] Where V1 and V2 are the complex forms of the two medium voltage output voltages, φ is the phase angle introduced by the phase-modulated winding, and Z is the equivalent impedance, which is used to describe the magnetic coupling effect between the windings. Δφ is the fine-tuning angle in the actual phase modulation process, H(φ) is the harmonic correction term, which is used to compensate for the high-order harmonic distortion in the phase modulation process. The segmented phase modulation winding structure and its formula design support precise adjustment of the phase angle step by step, thereby optimizing the power flow distribution of the power grid under different load conditions and improving the flexibility of system regulation.

[0049] As a technical solution for further implementation of this scheme, the voltage amplitude after the compensation winding is adjusted satisfies the following formula:

[0050]

[0051] Where V comp is the output voltage after compensation, γ(k)=1+k 2 It is used to describe the nonlinear amplification effect of the compensation coefficient k on the output voltage, satisfying k>0 and k≤2. η(t) is the dynamic stability coefficient, which is used for dynamic compensation control within the period T. It is a periodic correction term that optimizes the dynamic response under short-term fluctuations. The compensation winding adjusts the voltage amplitude through the dynamic stability coefficient and the periodic correction term, significantly reducing the impact of grid voltage fluctuations on equipment and loads, and ensuring power supply quality.

[0052] As a technical solution for further implementation of this solution, the phase-adjusting switch is used to switch the connection state of the phase-adjusting winding. By selecting different winding segments, the phase angle of the medium-voltage output is dynamically adjusted to meet various power grid power flow control requirements. By dynamically switching the winding connection state through the phase-adjusting switch, the operation convenience and control efficiency of the medium-voltage output phase angle adjustment are optimized to adapt to various power grid scenarios.

[0053] As a technical solution for further implementation of this scheme, the transformer is designed with a modular component structure. The voltage regulating winding 2, the phase regulating winding 4 and the compensation winding 5 can be replaced and maintained independently. The modular design improves the independence of the transformer components, making maintenance, replacement and expansion easier, while significantly reducing the full life cycle cost of the equipment.

[0054] By adding phase-adjusting windings and switches to the wiring structure of the auto-coupling step-down transformer and adopting a special wiring method, the phase shifting function between the two sides of the transformer and the voltage reduction function between the power supply side (high voltage) and the load side (medium voltage or low voltage) can be realized. For the medium voltage between the two sides, the phase angle of the voltage can be changed and adjusted by the phase-adjusting switch. The voltage amplitude of one medium voltage can be kept equal to that of the other through the compensation winding, or the medium voltage on this side can be regulated separately; for the power supply side (high voltage) and the load side (medium voltage or low voltage), the voltage ratio can be changed and the voltage amplitude can be adjusted by the voltage regulating switch to ensure that the line end voltage maintains an unchanged amplitude when the power grid fluctuates.

[0055] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A winding connection structure of an auto-coupling step-down phase-shifting transformer, comprising a three-phase transformer, characterized in that: Each phase of the transformer comprises a high-voltage winding (1), a voltage regulating winding (2), a common winding (3), a phase-adjusting winding (4), a compensation winding (5), a low-voltage winding (6) and a phase-adjusting switch; The high-voltage winding (1) is used to receive a high-voltage power supply; The voltage regulating winding (2) is connected in series with the high voltage winding (1) to adjust the voltage amplitude and realize the voltage reduction function between the high voltage and the medium voltage; The common winding (3) is connected in series with the voltage regulating winding (2) to form an auto-coupling connection structure. The common winding (3) provides a medium voltage output and realizes a phase regulation function in combination with the phase regulating winding (4). The phase-adjusting winding (4) is connected to the common winding (3) and the voltage-adjusting winding (2); The compensating winding (5) is used to adjust the amplitude of the medium voltage output voltage to ensure the symmetry of the multi-channel medium voltage voltage; The low voltage winding (6) is used to provide a low voltage output; The phase-adjusting switch is connected in series in the phase-adjusting winding and is used to switch the phase-adjusting state to achieve phase angle adjustment.

2. The winding connection structure of the auto-coupling step-down phase-shifting transformer according to claim 1 is characterized in that: The transformer has a low-voltage winding (6), a voltage regulating winding (2), a common winding (3), a high-voltage winding (1), a phase-adjusting winding (4), and a compensating winding (5) on each iron core column. The transformer has a high-voltage winding (1), a voltage regulating winding (2), a common winding (3), a phase-adjusting winding (4), a compensating winding (5), and a low-voltage winding (6) on each iron core column of each phase, and each winding is an independent unit.

3. The winding connection structure of the auto-step-down phase-shifting transformer according to claim 1 is characterized in that: The high-voltage winding (1) of each phase of the transformer is sequentially connected in series with the voltage regulating winding (2) and the common winding (3), and the tail ends of the three-phase series windings are connected to form a neutral point terminated at phase 0, thereby realizing a high- and medium-voltage auto-coupling structure.

4. The winding connection structure of the auto-step-down phase-shifting transformer according to claim 1 is characterized in that: The connection point between the common winding (3) and the voltage regulating winding (2) leads to medium voltage line terminals LA1, LB1 and LC1; the connection point is respectively connected to the phase regulating windings (4) of different phases, and the phase regulating windings are connected to the compensation windings (5) after being connected in series with the phase regulating switches step by step; another group of medium voltage line terminals LA2, LB2 and LC2 are respectively led out of the three phases; the three-phase low voltage windings (6) are connected in a triangle to form low voltage side line terminals a, b, c.

5. The winding connection structure of the auto-step-down phase-shifting transformer according to claim 1 is characterized in that: The high-voltage winding (1), the voltage regulating winding (2) and the common winding (3) adopt a Yad-type connection method, and the neutral point of the common winding (3) is grounded.

6. The winding connection structure of the auto-step-down phase-shifting transformer according to claim 1 is characterized in that: The phase-adjusting winding (4) is designed with a segmented structure, and the phase-adjusting winding supports step-by-step adjustment of the phase angle φ. The relationship of the phase angles satisfies the following formula: Where V1 and V2 are the complex forms of the two medium voltage output voltages, φ is the phase angle introduced by the phase-modulated winding, and Z is the equivalent impedance, which is used to describe the magnetic coupling effect between the windings. Δφ is the fine-tuning angle in the actual phase modulation process, and H(φ) is the harmonic correction term, which is used to compensate for the high-order harmonic distortion in the phase modulation process.

7. The winding connection structure of the auto-step-down phase-shifting transformer according to claim 1 is characterized in that: The voltage amplitude after the compensation winding is adjusted satisfies the following formula: Where V comp is the output voltage after compensation, γ(k)=1+k 2 It is used to describe the nonlinear amplification effect of the compensation coefficient k on the output voltage, satisfying k>0 and k≤2. η(t) is the dynamic stability coefficient, which is used for dynamic compensation control within the period T. is a periodic correction term that optimizes the dynamic response under short-term fluctuations.

8. The winding connection structure of the auto-coupling step-down phase-shifting transformer according to claim 1 is characterized in that: The phase-adjusting switch is used to switch the connection state of the phase-adjusting winding. By selecting different winding segments, the phase angle of the medium voltage output is dynamically adjusted to meet various power grid flow control requirements.

9. The winding connection structure of the auto-step-down phase-shifting transformer according to claim 1 is characterized in that: The transformer is designed with a modular component structure, and the voltage regulating winding (2), the phase regulating winding (4) and the compensating winding (5) can all be replaced and maintained independently.

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