Split type modularized hybrid distribution transformer

Abstract

The utility model relates to a split type modularized hybrid distribution transformer which comprises an oil tank unit and an external cabinet unit, and the oil tank unit comprises a main winding, an auxiliary winding, an auxiliary series winding and an on-load tap changer; the primary and secondary windings and the auxiliary series winding adopt two groups of three-phase independent single-phase iron core groups; the external cabinet unit comprises a series-parallel converter, a coordination controller, an on-load voltage regulation controller and a bypass module. According to the utility model, the electromagnetic component and the power electronic equipment are physically separated through the split type design, the unbalanced magnetic flux is reduced through the three-phase independent magnetic circuit, and the electromagnetic coupling interference is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of power distribution equipment, and particularly relates to a split modular hybrid distribution transformer. Background Art

[0002] With the large-scale access of distributed new energy and the development of diversified loads, traditional distribution transformers are facing severe challenges in aspects such as voltage regulation and three-phase balance.

[0003] In the prior art, conventional oil-immersed transformers rely on mechanical on-load tap changers for voltage regulation, with slow response speed and difficulty in coping with instantaneous voltage over-limits (the fluctuation range can reach ±20%) caused by fluctuating power sources such as photovoltaic and wind power. Although hybrid distribution transformers introduce power electronic compensation technology, there are significant differences in the performance of series-parallel converters based on power electronics technology and electromagnetic windings in terms of life, heat dissipation, electromagnetic interference, etc., and there are many problems when integrated in the same oil tank. In addition, the three-phase common-core structure generates a flux superposition effect under unbalanced load conditions, causing additional eddy current losses and accelerating insulation aging.

[0004] Therefore, there is an urgent need for a hybrid distribution transformer structure that can separate power electronic devices from electromagnetic components and decouple the magnetic circuit. Summary of the Utility Model

[0005] In view of the deficiencies of the prior art, the utility model provides a split modular hybrid distribution transformer to solve the above problems.

[0006] The utility model provides the following technical solutions:

[0007] A split modular hybrid distribution transformer includes an oil tank unit and an external cabinet unit. The oil tank unit includes a main and secondary winding, an auxiliary series winding, and an on-load voltage regulator switch. The main and secondary winding and the auxiliary series winding both adopt two groups of three-phase independent single-phase iron core groups arranged coaxially and hierarchically, and the central axes of the main and secondary winding and the auxiliary series winding are axially misaligned. The external cabinet unit includes a series-parallel converter, a coordination controller, an on-load voltage regulation controller, and a bypass module.

[0008] Further, the central axes of the main and secondary winding and the auxiliary series winding are axially misaligned by not less than 400 mm.

[0009] Further, the oil tank unit is configured with a high-voltage connector, a low-voltage connector, and a series-parallel converter connector.

[0010] Further, the high-voltage connector is connected to 10 kV alternating current, the low-voltage connector is connected to the low-voltage outgoing line, and the series-parallel converter connector is connected to the series-parallel converter.

[0011] Further, in the series-parallel converter, the parallel converter adopts a three-phase full-bridge topology structure, and the series converter adopts three single-phase full-bridge topology structures to achieve three-phase voltage split-phase compensation.

[0012] Further, the external cabinet unit further includes an acquisition module, and the acquisition module is used to acquire voltage and current.

[0013] Further, the fuel tank unit is provided with a plate-type radiator; the external cabinet unit is internally provided with an isolation air duct and adopts air-cooled heat dissipation.

[0014] Further, the bypass module includes an antiparallel thyristor, a first magnetic latching relay (KM1), a second magnetic latching relay (KM2) and a circuit breaker (QF1) structure.

[0015] The utility model has the following beneficial technical effects:

[0016] The utility model realizes the physical separation of electromagnetic components and power electronic devices through the split design of the fuel tank unit and the external cabinet unit; the utility model also adopts two groups of three-phase independent single-phase iron core groups for the main and secondary windings and the auxiliary series winding, and the central axes of the main and secondary windings and the auxiliary series winding are axially misaligned. The three-phase independent magnetic circuit reduces the unbalanced magnetic flux and reduces the electromagnetic coupling interference. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of a split-type modular hybrid distribution transformer of the utility model;

[0018] Figure 2 is an electrical connection diagram of a split-type modular hybrid distribution transformer of the utility model;

[0019] Figure 3 is a schematic external structure diagram of the fuel tank unit of a split-type modular hybrid distribution transformer of the utility model;

[0020] Figure 4 is a three-view drawing of the fuel tank unit of a split-type modular hybrid distribution transformer of the utility model;

[0021] Figure 5 is a schematic structural diagram of the external cabinet unit of a split-type modular hybrid distribution transformer of the utility model.

[0022] The reference numerals in the drawings are:

[0023] 1. Fuel tank unit; 2. External cabinet unit; 3. Series-parallel converter joint; 4. High-voltage joint; 5. Low-voltage joint; 6. On-load tap-changer; 7. Main and secondary windings; 8. Auxiliary series winding; 9. Bypass module; 10. Series-parallel converter; 11. Coordination controller; 12. On-load tap-changing controller; 13. Acquisition module. Detailed implementation manners

[0024] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are only a part rather than all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0025] Embodiment

[0026] As Figure 1 shown in the figure is a schematic diagram of a split modular hybrid distribution transformer disclosed by the present utility model. Adopting a split modular design, it includes an oil tank unit 1 and an external cabinet unit 2. Figure 2 This is an electrical connection diagram of a split modular hybrid distribution transformer of the present utility model.

[0027] As Figure 3 shown, the oil tank unit 1 is configured with a high-voltage connector 4, a low-voltage connector 5, and a series-parallel converter connector 3. In this embodiment, the high-voltage connector 4 is connected to 10 kV alternating current, the low-voltage connector 5 is connected to a low-voltage outgoing line, and the series-parallel converter connector 3 is connected to a series-parallel converter 10 ( Figure 3 not specifically shown in the figure and can be referred to Figure 2 for the electrical connection diagram). As Figure 4 shown, the oil tank unit 1 further includes: a main and auxiliary winding 7, an auxiliary series winding 8, and an on-load tap-changer 6. Both the main and auxiliary winding 7 and the auxiliary series winding 8 adopt two groups of coaxial and layered three-phase independent single-phase iron core groups. The central axial misalignment distance between the main and auxiliary winding 7 and the auxiliary series winding 8 is L, and L is not less than 400 mm ± 1 mm. In this embodiment, the capacity of the hybrid distribution transformer is 400 kVA, the iron core uses 27ZH100 silicon steel sheets, the on-load tap-changer 6 adopts a strip nine-step tap-changer, the voltage regulation range is 10 kV (4 ± 5%), and the mechanical life exceeds 200,000 times.

[0028] As Figure 5 shown, the external cabinet unit 2 includes: a series-parallel converter 10, a coordination controller 11, an on-load tap-changing controller 12, a bypass module 9, and a collection module 13; the collection module 13 is used to collect voltage and current. In the series-parallel converter 10, the parallel converter adopts a three-phase full-bridge topology structure, and the series converter adopts three single-phase full-bridge topology structures to realize three-phase voltage phase-by-phase compensation. In this embodiment, the power of the series-parallel converter 10 is 65 kW, and the single-phase voltage regulation amplitude is 13 V.

[0029] The bypass module 9 in the external cabinet unit 2 includes an antiparallel thyristor, a first magnetic latching relay (KM1), a second magnetic latching relay (KM2), and a circuit breaker (QF1).

[0030] The oil tank unit 1 is provided with a plate heat sink for oil-cooled heat dissipation; the external cabinet unit 2 is internally provided with an isolation air duct for air-cooled heat dissipation. The intelligent heat dissipation system with oil-cooled and air-cooled zoning improves the heat dissipation effect.

[0031] The working principle of the present utility model: The transformer includes an oil tank unit 1 and an external cabinet unit 2, and the physical separation of electromagnetic components and power electronic devices is achieved through a split design; two sets of three-phase independent single-phase iron core structures are arranged in the oil tank unit 1, which are the main and auxiliary windings 7 and the auxiliary series winding 8 respectively, and both are arranged in a coaxial and layered manner. Moreover, the two sets of three-phase independent single-phase iron core structures are arranged in a coaxial and layered manner, and the central axes of the main and auxiliary windings 7 and the auxiliary series winding 8 are axially misaligned. This setting of three-phase independent magnetic circuits can reduce the unbalanced magnetic flux and reduce the electromagnetic coupling interference; the on-load tap-changer 6 is configured in the oil tank unit 1 for coarse voltage regulation, and the external cabinet unit 2 integrates a series-parallel converter 10, an on-load tap-changing controller 12, a coordination controller 11, and a bypass module 9 to achieve fast voltage dynamic compensation; the coordination controller 11 executes a two-level collaborative control algorithm for voltage regulation, including:

[0032] 1) Slow adjustment layer: Based on the voltage deviation value, the on-load tap-changing controller 12 is controlled to adjust the gear of the on-load tap-changer 6 for coarse voltage regulation.

[0033] 2) Fast compensation layer: Based on the voltage deviation value, the series-parallel converter 10 is controlled for fine voltage regulation, and the voltage regulation amplitude is generally slightly larger than the voltage regulation range of the on-load tap-changer 6.

[0034] When a short-circuit fault occurs in the main circuit, the coordination controller 11 triggers the antiparallel thyristor to conduct and the first magnetic latching relay (KM1) to open, bypassing the series-parallel converter 10 to protect the series-parallel converter 10; in addition, in order to replace, repair, and expand the series-parallel converter 10 under the condition that the main circuit of the hybrid distribution transformer is not powered off, the coordination controller 11 first triggers the second magnetic latching relay (KM2) to open, and then triggers the circuit breaker (QF1) to open, bypassing the series-parallel converter 10.

[0035] The present utility model reduces the unbalanced magnetic flux through three-phase independent magnetic circuits and reduces the electromagnetic coupling interference.

[0036] The above-described embodiments merely represent the specific implementation manners of the present utility model. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several modifications and improvements can still be made, and these all fall within the protection scope of the present utility model.

Claims

1. A split modular hybrid distribution transformer, characterized in that: It includes an oil tank unit and an external cabinet unit, the oil tank unit includes main and auxiliary windings, an auxiliary series winding and an on-load voltage regulating switch; the main and auxiliary windings and the auxiliary series winding both adopt two groups of coaxial layered three-phase independent single-phase iron core groups, and the central axes of the main and auxiliary windings and the auxiliary series winding are staggered; the external cabinet unit includes a series-parallel converter, a coordination controller, an on-load voltage regulating controller and a bypass module.

2. A split modular hybrid distribution transformer according to claim 1, characterized in that: The central axial offset of the main and auxiliary windings and the auxiliary series winding is not less than 400 mm.

3. A split modular hybrid distribution transformer according to claim 1, characterized in that: The oil tank unit is equipped with a high-voltage connector, a low-voltage connector and a series-parallel converter connector.

4. A split modular hybrid distribution transformer according to claim 3, characterized in that: The high-voltage connector is connected to 10kV AC power, the low-voltage connector is connected to a low-voltage outlet line, and the series-parallel converter connector is connected to a series-parallel converter.

5. A split modular hybrid distribution transformer according to claim 1, characterized in that: The parallel converter in the series-parallel converter adopts a three-phase full-bridge topology structure, and the series converter adopts three single-phase full-bridge topologies to achieve three-phase voltage split-phase compensation.

6. A split modular hybrid distribution transformer according to claim 1, characterized in that: The oil tank unit is provided with a plate-type radiator; the external cabinet unit is provided with a built-in isolation air duct.

7. A split modular hybrid distribution transformer according to claim 1, characterized in that: The bypass module includes an anti-parallel thyristor, a first magnetic latching relay, a second magnetic latching relay and a circuit breaker.

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