Device for suppressing harmonic waves of secondary circuit of wind turbine generator

Abstract

The utility model discloses a device for suppressing harmonic waves of a secondary circuit of a wind turbine generator, a fan is electrically connected with a converter, and the converter end is electrically connected to a medium-voltage switch cabinet through a main transformer and is connected to a power grid load through the medium-voltage switch cabinet; the converter end is connected to a secondary loop through an auxiliary transformer; a passive filter is arranged behind the auxiliary transformer; the passive filter comprises a three-phase loop, U1, V1 and W1 of the three-phase loop serve as input ends, U2, V2 and W2 serve as output ends to be connected into the secondary loop, inductors L1, L2 and L3 are arranged in the three-phase loop respectively, and a capacitor C is connected into the three-phase loop in a delta connection mode. The device solves the problem of harmonic waves generated in the application of the converter of the wind turbine generator, can effectively reduce the harmonic waves entering a secondary circuit, and protects secondary circuit equipment.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy, in particular to a device for suppressing secondary circuit harmonics of a wind turbine generator set. Background Art

[0002] The complementary energy systems of hydropower, wind power, and solar power represent a new load-based energy production model. This approach leverages the regulatory capacity of hydropower station reservoirs and integrates wind power, photovoltaic power, and hydropower stations to achieve complementary and mutually beneficial energy sources. Wind power boasts significant technological advantages and great development potential, and its penetration within the complementary energy structure of hydropower, wind power, and solar power continues to increase. However, the application of wind power to converters introduces significant harmonics, which have a significant impact on the wind power secondary circuit.

[0003] The secondary circuit of wind power refers to the circuit used to control, protect or power other equipment in the electrical system; it is mainly used to transmit signals, activate relays to trigger the operation of other electrical equipment; through the combination and connection of switches, relays, protection devices, control buttons, indicator lights and other components, it realizes the control and monitoring of various parts of the wind turbine system.

[0004] Current wind turbine harmonic control focuses primarily on reducing harmonic content in the power grid. However, a small amount of harmonics can enter the wind turbine's secondary circuit. Due to the high impedance of the secondary circuit, the harmonic voltage generated by the harmonic current entering the circuit is relatively large. Furthermore, loads such as the pitch controller in the circuit are sensitive to high-order harmonics (above the 11th order), making them prone to failure. Therefore, a device to suppress harmonics in the wind turbine's secondary circuit is needed to address this issue. Summary of the Invention

[0005] The technical problem to be solved by the utility model is to provide a device for suppressing harmonics in the secondary circuit of a wind turbine generator set, which is used to solve the harmonic problem generated in the application of the wind turbine generator set converter, can effectively reduce the harmonics entering the secondary circuit, and protect the secondary circuit equipment.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a device for suppressing harmonics in the secondary circuit of a wind turbine, including a wind turbine, which is electrically connected to a converter, and the converter end is electrically connected to a medium-voltage switchgear through a main transformer, and is connected to the grid load through the medium-voltage switchgear; the converter end is connected to the secondary circuit through an auxiliary transformer; and a passive filter is arranged after the auxiliary transformer.

[0007] Preferably, the fan is a double-winding fan, and an active filter is provided inside the fan.

[0008] Preferably, the converter is a dual-cabinet parallel converter.

[0009] Preferably, the passive filter includes a three-phase circuit, with U1, V1, and W1 of the three-phase circuit serving as input ends, and U2, V2, and W2 serving as output ends connected to the secondary circuit.

[0010] Preferably, inductors L1, L2, and L3 are respectively provided in the three-phase circuit, and the capacitor C is connected to the three-phase circuit in a triangle connection.

[0011] The beneficial effects of the utility model are as follows:

[0012] The combination of passive filters and active filters has a larger filtering capacity than active filters. By installing active filters at the unit, the harmonics generated by the wind turbine are reduced. At the same time, passive filters are installed at the secondary circuit. The harmonics generated by the wind turbine are filtered by the passive filter after entering the secondary circuit, so that the harmonics in the secondary circuit meet national standards and reduce damage to secondary circuit equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0014] Figure 1 It is a structural diagram of the utility model;

[0015] Figure 2 This is a schematic diagram of the passive filter circuit structure of the utility model.

[0016] In the figure: wind turbine 1, converter 2, main transformer 3, medium voltage switchgear 4, auxiliary transformer 6, secondary circuit 7, passive filter 8. DETAILED DESCRIPTION

[0017] Example 1:

[0018] like Figure 1-2 As shown, a device for suppressing harmonics in the secondary circuit of a wind turbine includes a wind turbine 1, which is electrically connected to a converter 2. The converter 2 is electrically connected to a medium-voltage switchgear 4 through a main transformer 3, and is connected to a grid load through the medium-voltage switchgear 4; the converter 2 is connected to a secondary circuit 7 through an auxiliary transformer 6; and a passive filter 8 is provided after the auxiliary transformer 6.

[0019] Preferably, the fan 1 is a dual-winding fan 1 , and an active filter is provided in the fan 1 .

[0020] Preferably, the converter 2 is a dual-cabinet parallel converter 2 .

[0021] Preferably, the passive filter 8 includes a three-phase circuit, with U1 , V1 , and W1 of the three-phase circuit serving as input ends, and U2 , V2 , and W2 serving as output ends connected to the secondary circuit 7 .

[0022] Preferably, inductors L1, L2, and L3 are respectively provided in the three-phase circuit, and the capacitor C is connected to the three-phase circuit in a triangle connection.

[0023] Example 2:

[0024] A certain wind power project involved a large 10MW wind turbine. During actual operation, significant harmonics were detected in the turbine's auxiliary power supply system. This caused frequent faults, including malfunctions in the pitch control system relay and circuit breaker tripping. The wind turbine was connected to the grid via a converter, with the main transformer connected to the load and the auxiliary transformer connected to the secondary circuit.

[0025] When no filter is installed, the three-phase voltage harmonic and current harmonic contents in the secondary circuit are shown in Table 1 below.

[0026] Phase sequence A B C Voltage harmonics THD(%) 9.0 8.6 7.8 Current harmonics THD(%) 23.5 19.7 21.3

[0027] Table 1: Voltage harmonics and current harmonics content

[0028] The unit is equipped with an active filter with a capacity of 100A. At the same time, a passive filter with parameters L = L1 / L2 / L3 = 0.121mH and C = 400uF is installed in a delta connection after the auxiliary transformer in the secondary circuit.

[0029] After the active + passive hybrid filter is connected, the secondary circuit harmonic voltage content is reduced to 3.34%, and the harmonic control effect is significant.

[0030] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. Equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A device for suppressing secondary circuit harmonics of a wind turbine generator set, characterized by: The invention comprises a fan (1), the fan (1) is electrically connected to a converter (2), the converter (2) is electrically connected to a medium-voltage switch cabinet (4) through a main transformer (3), and is connected to a grid load through the medium-voltage switch cabinet (4); the converter (2) is connected to a secondary circuit (7) through an auxiliary transformer (6); and a passive filter (8) is provided behind the auxiliary transformer (6).

2. The device for suppressing secondary circuit harmonics of a wind turbine generator set according to claim 1, characterized in that: The fan (1) is a double-winding fan, and an active filter is provided in the fan (1).

3. The device for suppressing secondary circuit harmonics of a wind turbine generator set according to claim 1, characterized in that: The converter (2) is a double-cabinet parallel converter (2).

4. The device for suppressing secondary circuit harmonics of a wind turbine generator set according to claim 1, characterized in that: The passive filter (8) includes a three-phase circuit, wherein U1, V1, and W1 of the three-phase circuit serve as input terminals, and U2, V2, and W2 serve as output terminals connected to a secondary circuit.

5. The device for suppressing secondary circuit harmonics of a wind turbine generator set according to claim 4, characterized in that: Inductors L1, L2, and L3 are respectively provided in the three-phase circuit, and capacitor C is connected to the three-phase circuit in a triangle connection.

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