Topological wiring of high-voltage frequency conversion station

Abstract

The high-voltage frequency conversion station topology wiring comprises an alternating-current frequency converter, the left side of the alternating-current frequency converter is connected with a power frequency starting resistor loop, and the right side of the alternating-current frequency converter is connected with a low-frequency-side reactor; the left side of the power frequency starting resistor loop is connected with a power frequency connection transformer and a power frequency power distribution device. The right side of the low-frequency side reactor is connected with a low-frequency connection transformer and a low-frequency power distribution device; the AC frequency converter is respectively connected to the power frequency power grid and the low frequency power grid through the power frequency connection transformer and the low frequency connection transformer, and the starting resistor and the reactor are arranged between the AC frequency converter and the transformer, so that the voltage level of the AC frequency converter is reduced through the power frequency connection transformer and the low frequency connection transformer on the premise of not influencing the function of the flexible frequency conversion station; the engineering investment of the frequency converter is saved, the occupied area of the frequency conversion station is saved, and the comprehensive benefit is remarkable.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage equipment, and in particular to a topological wiring of a high-voltage frequency conversion station. Background Art

[0002] The flexible low-frequency transmission system achieves the purpose of increasing transmission power, reducing the number of transmission circuits and outgoing line corridors by reducing the transmission frequency without increasing the voltage level. This technology not only has broad application prospects in large-scale renewable energy transmission scenarios such as offshore wind power, but also provides an effective solution for urban power grid interconnection.

[0003] The frequency conversion station is an important part of the flexible low-frequency power transmission technology, which realizes the connection between two power grids with different frequencies through the frequency converter. The AC frequency converter is the core component of the frequency conversion station and is the interactive carrier of the energy of the industrial and low-frequency power grids. Limited by the capacity level of power electronic devices, high-voltage and large-capacity frequency converters require a large number of sub-modules to be cascaded or paralleled, which is expensive and has large losses. Therefore, improving the initial investment and operating costs of the system is an urgent problem to be solved. The AC frequency converter selected in the prior art has not been stepped down by the industrial frequency connection transformer and the low-frequency connection transformer. The frequency conversion station occupies a large area and the frequency converter equipment investment is large. Summary of the invention

[0004] The main purpose of the present invention is to provide a high-voltage frequency conversion station topology wiring, aiming to solve the existing technical problems.

[0005] To achieve the above object, the present invention provides a high-voltage frequency conversion station topology wiring, including an AC frequency converter, wherein the left side of the AC frequency converter is connected to a power frequency starting resistance loop, and the right side is connected to a low-frequency side reactor;

[0006] The left side of the power frequency starting resistance circuit is connected to the power frequency connecting transformer and the power frequency distribution device;

[0007] The right side of the low-frequency side reactor is connected to a low-frequency connecting transformer and a low-frequency power distribution device.

[0008] Furthermore, the left phase of the AC converter and the right phase of the power frequency starting resistance loop are connected through a power frequency side reactor.

[0009] Furthermore, the right phase of the low-frequency side reactor is connected to the left phase of the low-frequency connecting transformer through a low-frequency starting resistance loop.

[0010] Furthermore, the topology of the AC converter may be a modular multi-level matrix converter.

[0011] Furthermore, the industrial frequency starting resistance circuit and the low frequency starting resistance circuit are both arranged on the transformer inverter side and are connected in parallel with the circuit breaker.

[0012] The beneficial effects of the present invention are embodied in:

[0013] The present invention connects the AC converter to the power frequency and low frequency power grids respectively through the power frequency connecting transformer and the low frequency connecting transformer, and arranges a starting resistor and a reactor between the AC converter and the transformer. Under the premise of not affecting the function of the flexible frequency conversion station, the voltage level of the AC converter is reduced through the power frequency connecting transformer and the low frequency connecting transformer, thereby saving the engineering investment of the frequency converter and the floor space of the frequency conversion station, and achieving remarkable comprehensive benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the topological structure wiring of the present invention.

[0015] Description of reference numerals:

[0016] 1. Power frequency distribution device; 2. Power frequency connecting transformer; 3. Power frequency starting resistance circuit; 4. Power frequency side reactor; 5. AC converter; 6. Low frequency side reactor; 7. Low frequency starting resistance circuit; 8. Low frequency step-up transformer; 9. Low frequency distribution device. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] See also Figure 1 The present invention provides a high-voltage frequency conversion station topology wiring, including an AC frequency converter 5, the left side of the AC frequency converter 5 is connected to a power frequency starting resistance loop 3, and the right side is connected to a low-frequency side reactor 6;

[0019] The left side of the power frequency starting resistance circuit 3 is connected to the power frequency connecting transformer 2 and the power frequency distribution device 1;

[0020] The right side of the low-frequency side reactor 6 is connected to a low-frequency connecting transformer 8 and a low-frequency power distribution device 9.

[0021] In one embodiment, the left phase of the AC converter 5 is connected to the right phase of the power frequency starting resistance loop 3 through the power frequency side reactor 4 .

[0022] In one embodiment, the right phase of the low-frequency side reactor 6 is connected to the left phase of the low-frequency connecting transformer 8 through a low-frequency starting resistance loop 7 .

[0023] Among them, the AC inverter 5 is a key device for low-frequency and industrial frequency power conversion. The inverter topology structure can use different forms such as M3C modular multi-level matrix converter to realize AC switching.

[0024] It should be noted that the converter topology can also be used for other cycloconverters and is not limited to modular multilevel matrix converters.

[0025] The low-frequency side reactor 6 is used to reduce the harmonic components of the voltage and current in the transmission line, prevent current discontinuity, and limit the peak current in the converter during circuit breaker period.

[0026] The power frequency starting resistance circuit 3 and the low frequency starting resistance circuit 7 are arranged on the transformer inverter side and connected in parallel with the circuit breaker to reduce the disturbance to the AC system and the impact on the inverter when the flexible power transmission system is started.

[0027] The power frequency connecting transformer 2 and the low frequency connecting transformer 8 provide a three-phase voltage source of appropriate level for the power electronic device and play a role of electrical isolation.

[0028] The industrial frequency power distribution device 1 and the low frequency power distribution device 9 realize the collection and grid connection of power transmission lines.

[0029] The main equipment investment of the frequency conversion station is the AC converter 5, which accounts for 40% of the total equipment investment. The cost of the AC converter is mainly the power electronic frequency conversion devices such as IGBT. The voltage level required by the project determines the number of frequency conversion devices, thereby determining the cost of the frequency converter.

[0030] The present invention connects the AC converter to the power frequency and low frequency power grids respectively through the power frequency connecting transformer and the low frequency connecting transformer, and arranges a starting resistor and a reactor between the AC converter and the transformer. Under the premise of not affecting the function of the flexible frequency conversion station, the voltage level of the AC converter is reduced through the power frequency connecting transformer and the low frequency connecting transformer, thereby saving the engineering investment of the frequency converter and the floor space of the frequency conversion station, and achieving remarkable comprehensive benefits.

[0031] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, back, etc., then the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0032] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, "multiple" refers to more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high voltage frequency conversion station topology wiring, characterized by: It comprises an AC frequency converter (5), wherein the left side of the AC frequency converter (5) is connected to an industrial frequency starting resistance circuit (3), and the right side is connected to a low frequency side reactor (6); The left side of the power frequency starting resistance circuit (3) is connected to the power frequency connecting transformer (2) and the power frequency power distribution device (1); The right side of the low-frequency side reactor (6) is connected to a low-frequency connecting transformer (8) and a low-frequency power distribution device (9).

2. A high-voltage frequency conversion station topology connection as claimed in claim 1, characterized in that: The left phase of the AC converter (5) is connected to the right phase of the power frequency starting resistance circuit (3) via a power frequency side reactor (4).

3. A high-voltage frequency conversion station topology connection according to claim 1, characterized in that: The right phase of the low-frequency side reactor (6) is connected to the left phase of the low-frequency connecting transformer (8) via a low-frequency starting resistance loop (7).

4. A high-voltage frequency conversion station topology connection according to claim 1, characterized in that: The topological structure of the AC frequency converter (5) is a modular multi-level matrix converter.

5. A high-voltage frequency conversion station topology connection as claimed in claim 1, characterized in that: The industrial frequency starting resistance circuit (3) and the low frequency starting resistance circuit (7) are both arranged on the transformer frequency converter side and are connected in parallel with the circuit breaker.

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