Broadband harmonic impedance testing device for wind power grid

Abstract

The utility model discloses a broadband harmonic impedance testing device for a wind power grid. The broadband harmonic impedance testing device comprises a signal generation module, a power amplification module, a coupling module, a measurement module and a data processing and display module, the output end of the signal generation module is connected with the input end of the power amplification module, the output end of the power amplification module is connected with a wind power grid test access point through the coupling module, and the input end of the measurement module is connected to the position, corresponding to the wind power grid test access point, of the coupling module through a first electromagnetic shielding twisted pair. The acquisition module is used for acquiring voltage and current signals of a wind power grid test access point; the output end of the measuring module is connected with the data processing and displaying module through a second electromagnetic shielding twisted pair. According to the utility model, through the modular design of various independent functions, the problem that the test scene is limited is solved, the anti-interference capability is improved, and the precision of subsequent calculation of harmonic impedance is further improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to wind power grid system technical field especially relates to a kind of for wind power grid broadband harmonic impedance testing device. BACKGROUND

[0002] As an important renewable energy form, the proportion of wind power in power systems continues to rise. After large-scale access of wind farms to power grids, their operating characteristics differ significantly from traditional thermal power. The large number of power electronic converter devices used by wind turbines, while achieving efficient conversion and control of wind energy, have become the main source of harmonics. These harmonic currents injected into the wind power grid can cause a series of serious problems such as voltage distortion, equipment overheating, and relay protection misoperation, negatively affecting the safety, stability, and power quality of the wind power grid and even the entire power system.

[0003] Currently, conventional methods for testing harmonic impedance in wind power grids have drawbacks in many aspects, making it difficult to meet actual needs. In existing patents, such as patent application number CN202210122445.1, a wind power grid broadband harmonic impedance testing device and method are disclosed, which includes a step-down transformer, a harmonic source converter, and a converter reactor. However, this testing device is limited by overall control strategies to adjust harmonic parameters, with poor flexibility, making it difficult to test harmonic impedance flexibly. Moreover, the testing scenario in the above-mentioned patent is relatively single, with relatively fixed control strategies, making adjustment cumbersome and difficult to directly apply to other types of equipment or different testing needs in other fields. Furthermore, the functions of the measurement device parts in the above-mentioned patent are tightly coupled in the hierarchical control strategy, such as the adjustment of the harmonic source converter, which may involve coordinated changes in the top power control, intermediate harmonic control, and bottom voltage control. This results in a complex upgrade and maintenance process.

[0004] In addition to the above-mentioned existing patents, testing devices in existing technologies are generally connected to wind power grid test access points through cables, and the signal transmission of the testing devices is also a simple transmission through cables. However, there is electromagnetic interference around the wind power grid system, which belongs to an environment with serious electromagnetic pollution. In such an environment, signals are easily disturbed, and general transmission cables have weak anti-interference ability, which can lead to data transmission errors, thereby affecting the accuracy of subsequent harmonic impedance calculation. UTILITY MODEL CONTENT

[0005] To address the shortcomings of existing technologies, the utility model provides a wind power grid broadband harmonic impedance testing device, which solves the problem of limited testing scenarios through various independent functional modular designs, improves anti-interference ability, and thus improves the accuracy of subsequent harmonic impedance calculation.

[0006] In order to achieve the above object, the utility model adopts the following technical scheme:

[0007] A kind of for wind power network broadband harmonic impedance testing device, comprising: the testing device is connected with wind power network test access point, characterized by, comprising: signal generating module, power amplifier module, coupling module, measurement module and data processing and display module;

[0008] The signal generating module is used to output test signal, the output of the signal generating module is connected with the input of power amplifier module, the power amplifier module is used to amplify the test signal, the output of the power amplifier module is connected with wind power network test access point by coupling module, the input of the measurement module is connected to the corresponding position of coupling module and wind power network test access point by first electromagnetic shielded twisted pair, for collecting the voltage and current signal of wind power network test access point;The output of the measurement module is connected with the data processing and display module by second electromagnetic shielded twisted pair.

[0009] As a further technical scheme, the output of the signal generating module is connected with the input of power amplifier module by low-noise shielded cable, the low-noise shielded cable is double-layer shielding structure, and the low-noise shielded cable includes inner layer made of copper braid, outer layer made of aluminum foil and multiple strands of silver-plated copper wire.

[0010] As a further technical scheme, the power amplifier module includes preamplifier circuit, power amplifier circuit and filter circuit in sequence, the input of the preamplifier circuit is connected with the output of the signal generating module, for obtaining test signal, and the output of the filter circuit is connected with the input of the coupling module.

[0011] As a further technical scheme, the output of the filter circuit is connected with the input of the coupling module by transmission bus, and the transmission bus includes conductor, insulation layer wrapped outside the conductor and double-layer metal shielding net woven outside the insulation layer.

[0012] As a further technical scheme, the output of the coupling module is connected with wind power network test access point by plug-in electrical connector.

[0013] As a further technical scheme, the measurement module includes voltage sensor and current sensor, the voltage sensor and current sensor are connected with one end of the first electromagnetic shielded twisted pair by electromagnetic shielded connecting bridge, and the other end of the first electromagnetic shielded twisted pair is connected with the corresponding position of coupling module and wind power network test access point.

[0014] As a further technical solution, the electromagnetic shielding connecting bridge is a multi-layer composite structure, comprising a transmission conductor, an outer layer of the transmission conductor being covered with a shielding material, an outer layer of the shielding material being provided with a copper foil shielding layer, and an outer side of the copper foil shielding layer being covered with a reinforcing layer made of carbon fiber material.

[0015] As a further technical solution, one end of the second electromagnetic shielding twisted pair line is connected to the output ends of the voltage sensor and the current sensor respectively, and the other end of the second electromagnetic shielding twisted pair line is connected to the input end of the data processing and display module.

[0016] As a further technical solution, the first electromagnetic shielding twisted pair line and the second electromagnetic shielding twisted pair line are both composed of two mutually twisted insulated conductors, and a metal shielding mesh is woven on the outer layers of the first electromagnetic shielding twisted pair line and the second electromagnetic shielding twisted pair line.

[0017] As a further technical solution, the data processing and display module is provided with a high-speed data acquisition interface, and the high-speed data acquisition interface is matched with the second electromagnetic shielding twisted pair line.

[0018] The one or more technical solutions of the utility model have the following beneficial effects:

[0019] (1) The utility model discloses a signal generating module, power amplification module, coupling module, measurement module and data processing and display module and the like independent function module are designed, since each module is independent, the flexibility is better, can test the harmonic impedance more flexibly, and then can satisfy various test scenes, for example, when testing small wind power network, the amplification multiple of power amplification module can be appropriately reduced, and when testing large wind power network, the amplification multiple is improved, and the operation is simple and convenient.

[0020] (2) The utility model discloses that the measurement module and the coupling module are connected with the corresponding position of wind power network test access point through the first electromagnetic shielding twisted pair line, and the measurement module and the data processing and display module are connected through the second electromagnetic shielding twisted pair line, and are connected through the first electromagnetic shielding twisted pair line and the second electromagnetic shielding twisted pair line, can effectively avoid electromagnetic interference in wind power network, avoid the interference of signal, guarantee the accuracy of data transmission, and then improve the precision of subsequent calculation harmonic impedance. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings accompanying the specification provide further understanding of the utility model, and the illustrative embodiments of the utility model and the description thereof are used to explain the utility model, and do not constitute improper limitation on the utility model.

[0022] Figure 1 This is a schematic diagram of the structure of the testing device of this utility model;

[0023] Figure 2 This is the circuit diagram of the power amplifier module of this utility model;

[0024] Figure 3 This is a circuit diagram of the coupling module of this utility model.

[0025] Among them: 101, preamplifier circuit; 102, power amplifier circuit; 103, filter circuit; 104, coupling circuit. Detailed Implementation

[0026] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] Example 1

[0028] This invention provides a device for testing the broadband harmonic impedance of wind power grids, such as... Figure 1 As shown, the testing device is connected to the wind power grid test access point. The testing device includes a signal generation module, a power amplification module, a coupling module, a measurement module, and a data processing and display module. Specifically, the signal generation module outputs test signals to meet the complex multi-condition testing requirements of the wind power grid. The core of the signal generation module uses an advanced Direct Digital Synthesis (DDS) chip with ultra-fine frequency resolution up to 0.01Hz, accurately outputting signals with a continuously adjustable frequency range of 20Hz-20kHz. This chip has a built-in high-capacity high-speed storage unit, pre-storing various basic waveform data such as sine waves, square waves, and triangular waves, enabling diverse waveform output. A high-precision digital-to-analog converter (DAC) is externally configured to the DDS chip, converting the digital signal generated by the DDS chip into an analog voltage signal with a conversion accuracy of 16 bits, ensuring a smooth and low-distortion output analog signal. Combined with a low-pass filter, high-frequency spurious components are filtered out, resulting in a clean test signal source. In this embodiment, the output of the signal generation module is connected to the input of the power amplifier module. Specifically, the output of the signal generation module is connected to the input of the power amplifier module through a low-noise shielded cable. The low-noise shielded cable has a double-layer shielding structure, which includes an inner layer made of copper braided mesh, an outer layer made of aluminum foil, and multiple strands of silver-plated copper wires. The inner layer made of copper braided mesh can shield high-frequency electromagnetic interference, the outer layer made of aluminum foil can shield low-frequency electric field interference, and the multiple strands of silver-plated copper wires ensure low signal loss and high-quality transmission.

[0029] In the embodiment, the power amplification module is used to amplify the test signal, and the output end of the power amplification module is connected to the wind power grid test access point through the coupling module. Figure 2 As shown in the figure, the power amplification module sequentially comprises a preamplification circuit 101, a power amplification circuit 102 and a filter circuit 103. The input end of the preamplification circuit is connected to the output end of the signal generation module, and is used to obtain the test signal. The output end of the filter circuit is connected to the input end of the coupling module. Specifically, the preamplification circuit 101 comprises resistors R4, R6, R8, R9, a capacitor C8, a NPN type transistor Q3, resistors R10, R11, R12, diodes D2, D3, D4, a PNP type transistor Q4, a NPN type transistor Q6 and a capacitor C2. The base of the transistor Q3 is connected to the input end of the power amplification module. The emitter of the transistor Q3 is connected to the ground through the resistor R9 and the capacitor C8. The collector of the transistor Q3 is connected to the input end of the power amplification module through the resistor R6 and the resistor R4. One end of the resistor R8 is connected to the input end of the power amplification module, and the other end of the resistor R8 is connected to the ground. The base of the transistor Q4 is connected to the collector of the transistor Q3. The emitter of the transistor Q4 is connected to the input end of the power amplification module through the resistor R4, i.e. the emitter of the transistor Q4 is connected to the other end of the capacitor C1 through the resistor R4. The collector of the transistor Q4 is connected to the collector of the transistor Q6 through the diode D2. The capacitor C3 is connected between the base and the collector of the transistor Q4. The base of the transistor Q6 is connected to the input end of the power amplification module through the resistor R10 and the resistor R4. The emitter of the transistor Q6 is connected to the ground through the resistor R12. The anode of the diode D3 is connected to the base of the transistor Q6. The cathode of the diode D3 is connected to the anode of the diode D4. The cathode of the diode D4 is connected to the ground. One end of the resistor R11 is connected to the emitter of the transistor Q3, and the other end of the resistor R11 is connected to the power amplification circuit. The power amplification circuit 102 comprises a NPN type transistor Q5, a capacitor C9 and a PNP type transistor Q7. The base of the transistor Q5 is connected to one output end of the preamplification circuit 101. The emitter of the transistor Q5 is connected to the emitter of the transistor Q7. The collector of the transistor Q5 is connected to the power supply voltage VCC. The base of the transistor Q7 is connected to the other output end of the preamplification circuit 101. The emitter of the transistor Q7 is connected to one end of the capacitor C9. The collector of the transistor Q7 is connected to the ground. The other end of the capacitor C9 is connected to the filter circuit 103. The filter circuit 103 comprises an inductor L2, a capacitor C10, a capacitor C11 and an inductor L3. One end of the inductor L2 is connected to the power amplification circuit. The other end of the inductor L2 is connected to one end of the capacitor C10. The other end of the capacitor C10 is connected to one end of the inductor L3. One end of the capacitor C11 is connected to the other end of the capacitor C10. The other end of the capacitor C11 is connected to the other end of the inductor L3.

[0030] The output end of the filter circuit 103 is connected to the input end of the coupling module through a transmission bus, which includes a conductor, an insulating layer wrapped outside the conductor, and a double-layer metal shielding net woven outside the insulating layer. The coupling module is integrated with a coupling circuit 104, as shown in Figure 3 The coupling circuit 104 includes a capacitor C12, an inductor L4, a coupling coil BT1, and a TVS tube. One end of the TVS tube is connected to one end of a first coil N1 in the coupling coil BT1, the other end of the TVS tube is connected to the other end of the first coil N1 in the coupling coil BT1, and the other end of the TVS tube is also connected to the ground. One end of a second coil N2 in the coupling coil BT1 is connected to the firewire of the power line through the capacitor C12 and the inductor L4, and the other end of the second coil N2 in the coupling coil BT1 is connected to the zero line N of the power line. The output end of the coupling module is connected to the wind power grid test access point through a plug-in electrical connector.

[0031] In the embodiment, as shown in Figure 1 The input end of the measurement module is connected to the corresponding position of the coupling module and the wind power grid test access point through a first electromagnetic shielding twisted pair for collecting the voltage and current signals of the wind power grid test access point. The output end of the measurement module is connected to the data processing and display module through a second electromagnetic shielding twisted pair for calculating the harmonic impedance according to the voltage and current signals. The calculation process is performed in the data processing and display module. This part is a prior art scheme, and the overall structure and circuit are protected in the embodiment, and no improvement is made to the above-mentioned calculation process. The measurement module includes a voltage sensor and a current sensor. The voltage sensor and the current sensor are connected to one end of the first electromagnetic shielding twisted pair through an electromagnetic shielding connecting bridge. The other end of the first electromagnetic shielding twisted pair is connected to the corresponding position of the coupling module and the wind power grid test access point. The electromagnetic shielding connecting bridge is a multi-layer composite structure, which includes a transmission conductor, a shielding material covering the outer layer of the transmission conductor, a copper foil shielding layer arranged on the outer layer of the shielding material, and a reinforcing layer made of carbon fiber material covering the outer side of the copper foil shielding layer. The other end of the second electromagnetic shielding twisted pair is connected to the input end of the data processing and display module. In the embodiment, the first electromagnetic shielding twisted pair and the second electromagnetic shielding twisted pair are both composed of two insulated conductors twisted with each other, and the outer layer of the first electromagnetic shielding twisted pair and the second electromagnetic shielding twisted pair is woven with a metal shielding net. A high-speed data acquisition interface is arranged in the data processing and display module, which is matched with the second electromagnetic shielding twisted pair.

[0032] The above merely describes preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A wind grid wideband harmonic impedance testing device, the testing device is connected with a wind grid testing access point, characterized in that, The application relates to a wind power grid test access point signal generator. The output end of the signal generator is connected with the input end of the power amplifier through a low-noise shielding cable, the low-noise shielding cable is a double-layer shielding structure, and the low-noise shielding cable comprises an inner layer made of copper braid, an outer layer made of aluminum foil and a plurality of silver-plated copper wires. The power amplifier comprises a preamplifier circuit, a power amplifier circuit and a filter circuit in sequence, the input end of the preamplifier circuit is connected with the output end of the signal generator, the filter circuit is connected with the input end of the coupling module.

2. A device for wind power grid broadband harmonic impedance testing according to claim 1, characterized in that, The output end of the filter circuit is connected with the input end of the coupling module through a transmission bus, the transmission bus comprises a conductor, an insulation layer wrapped outside the conductor and a double-layer metal shielding net woven outside the insulation layer.

3. A device for wind power grid broadband harmonic impedance testing according to claim 1, characterized in that, The output end of the coupling module is connected with the wind power grid test access point through a plug-in electrical connector.

4. A device for wind power grid wideband harmonic impedance testing according to claim 3, characterized in that, The measuring module comprises a voltage sensor and a current sensor, the voltage sensor and the current sensor are connected with one end of the first electromagnetic shielding twisted pair through an electromagnetic shielding connecting bridge, and the other end of the first electromagnetic shielding twisted pair is connected with the coupling module and the corresponding position of the wind power grid test access point.

5. A device for wind farm wideband harmonic impedance testing as claimed in claim 4, wherein, The electromagnetic shielding connecting bridge is a multi-layer composite structure, comprising a transmission wire, a shielding material is covered on the outer layer of the transmission wire, a copper foil shielding layer is arranged on the outer layer of the shielding material, and an enhanced layer made of carbon fiber material is covered on the outer side of the copper foil shielding layer.

6. A device for wind power grid wideband harmonic impedance testing according to claim 1, characterized in that, One end of the second electromagnetic shielding twisted pair is connected with the output end of the voltage sensor and the current sensor respectively, and the other end of the second electromagnetic shielding twisted pair is connected with the input end of the data processing and display module.

7. A device for wind farm wideband harmonic impedance testing as claimed in claim 6, wherein, The first electromagnetic shielding twisted pair and the second electromagnetic shielding twisted pair are both composed of two mutually twisted insulated wires, and metal shielding nets are woven on the outer layers of the first electromagnetic shielding twisted pair and the second electromagnetic shielding twisted pair.

8. A device for wind power grid wideband harmonic impedance testing as claimed in claim 6, characterized in that, The data processing and display module is provided with a high-speed data acquisition interface which is matched with the second electromagnetic shielding twisted pair.

9. A device for wind power grid broadband harmonic impedance testing according to claim 1, characterized in that, ​ 10. The device for wind power grid broadband harmonic impedance test according to claim 1, characterized in that, ​

Images