Monitoring and early warning device for higher harmonic resonance of traction substation

Abstract

The utility model relates to a traction substation higher harmonic resonance monitoring and early warning device which comprises a signal preprocessing unit, an acquisition unit, a data processing unit, a communication unit and a control unit. The signal preprocessing unit, the acquisition unit, the data processing unit and the communication unit are connected in sequence, and the control unit is respectively connected with the units. According to the utility model, the problems of low sampling precision, inaccurate sampling result and the like caused by higher harmonic resonance are avoided through the adjustable gain module, and data such as real-time harmonic waves and the like can be sent to a remote server for more accurately completing online monitoring and intelligent early warning of transient disturbance of the traction power supply system.

Description

Technical Field

[0001] This utility model relates to the field of high-order harmonic resonance monitoring technology, specifically to a high-order harmonic resonance monitoring and early warning device for traction substations. Background Technology

[0002] With the rapid development of electrified railways and the continuous increase in train power, a series of power supply and transformation safety problems caused by "vehicle-grid" mismatch have emerged, mainly manifested as high-order harmonic resonance problems. For example, AC-DC-AC electric locomotives have characteristics such as rapid movement, violent power fluctuations, and nonlinearity. Due to differences in the electrical structure, control technology, and switching frequency of electric locomotives, different high-order characteristic harmonics are emitted, making the high-order harmonic characteristics of the traction power supply system more complex and greatly increasing the possibility of high-order harmonic resonance in the system. This leads to frequent high-order harmonic resonance phenomena in the traction power supply system, with continuously amplified harmonic voltage and current amplitudes and severely distorted waveforms. The oscillation frequency ranges from hundreds to thousands of hertz, causing accidents such as power supply equipment burnout and train stoppages.

[0003] Electrified railway transportation organization and traction load are unique. A comprehensive understanding of the high-order harmonic resonance within the system, an assessment of the utilization and weaknesses of traction power supply equipment, and a basis for adjusting transportation organization are urgently needed for railway transportation production.

[0004] Currently, existing traction substations mainly focus on the daily status of the power supply equipment and its protection functions after a fault. At the system level, they lack the ability to identify abnormal operating conditions of high-order harmonic resonance "vehicle-grid" coupling and matching. Utility Model Content

[0005] To address the above technical problems, this utility model provides a high-order harmonic resonance monitoring and early warning device for traction substations. This device preprocesses signals of different amplitudes through an adjustable gain module, making them closer to the reference voltage for ADC sampling, thus achieving higher sampling accuracy. Simultaneously, by setting up a multi-channel acquisition unit, including 16 signal monitoring terminals, it can acquire 8 voltage signals and 8 current signals, record the fundamental and high-order harmonic data of the traction load, and realize a safety early warning function.

[0006] The technical solution of this utility model is as follows:

[0007] A high-order harmonic resonance monitoring and early warning device for traction substations includes a signal preprocessing unit 1, an acquisition unit 2, a data processing unit 3, a communication unit 4, and a control unit 5. The signal preprocessing unit 1, the acquisition unit 2, the data processing unit 3, and the communication unit 4 are connected in sequence, and the control unit 5 is connected to the signal preprocessing unit 1, the acquisition unit 2, the data processing unit 3, and the communication unit 4 respectively.

[0008] The signal preprocessing unit 1 includes an adjustable gain circuit 12 and an adjustable gain selection circuit 13; the input signal 11 is the voltage and current waveform of the high-order harmonic resonance of the traction substation; the adjustable gain circuit 12 performs multi-level processing on the input signal 11, and the gain amplitude is more flexibly controlled, thereby achieving a suitable range for the AD chip sampling reference; the adjustable gain selection circuit 13 is used to select an appropriate gain multiple for the amplitude partitioning of different high-order harmonic resonances to adapt to different harmonic resonance conditions.

[0009] The acquisition unit 2 includes a voltage sensor 21, a current sensor 22, a data acquisition circuit 23, and an analog-to-digital converter (AD converter) 24. The voltage sensor 21 is used to detect voltage signals, the current sensor 22 is used to detect current signals, and the data acquisition circuit 23 is connected to the voltage sensor 21 and the current sensor 22 to realize real-time online monitoring and acquisition of voltage and current signals. The AD converter 24 is connected to the data acquisition circuit 23 and the data processing unit 3 to perform high-precision conversion between analog and digital quantities.

[0010] The data processing unit 3 uses the existing FFT algorithm to calculate the harmonic voltage content rate and harmonic current content rate respectively, and then calculates the total harmonic distortion rate of voltage and the total harmonic distortion rate of current.

[0011] The communication unit 4 transmits the total harmonic distortion of voltage and total harmonic distortion of current obtained by the data processing unit 3 to the remote server 7 via wireless communication.

[0012] Furthermore, the device also includes a housing 6, in which a signal preprocessing unit 1, an acquisition unit 2, a data processing unit 3, a communication unit 4, and a control unit 5 are integrated.

[0013] Furthermore, the signal preprocessing unit 1 is connected to the secondary monitoring terminal of the voltage transformer of the traction substation monitoring cabinet via a probe, and to the secondary coil of the current transformer of the traction substation monitoring cabinet via a dedicated current clamp.

[0014] Furthermore, the acquisition unit 2 has a multi-channel acquisition function, with each channel acquiring voltage or current data of one branch.

[0015] Furthermore, the acquisition unit 2 includes 16 signal monitoring terminals, which can acquire 8 channels of voltage signals and 8 channels of current signals.

[0016] Furthermore, the control unit 5 is used to coordinate the operation of the signal preprocessing unit 1, the acquisition unit 2, the data processing unit 3, and the communication unit 4. The control unit 5 also integrates a GPS positioning device and a data storage circuit. The GPS positioning device is used to provide position parameters for wide-area synchronous measurement of multiple traction substations. The data storage circuit is used to uniformly store the harmonic components of the voltage and current of the traction substations obtained by this device, as well as the total harmonic distortion rate and the waveform data (amplitude, phase, frequency, etc.) of the voltage and current.

[0017] The beneficial effects of this utility model are as follows:

[0018] (1) The high-order harmonic resonance monitoring and early warning device for traction substations provided in this application adopts wide-area measurement technology and preprocesses the input signal to make it closer to the reference voltage range of the AD analog-to-digital conversion circuit, thereby avoiding problems such as low sampling accuracy and inaccurate sampling results caused by high-order harmonic resonance.

[0019] (2) The device provided in this application adopts a standard network protocol, which can send real-time harmonic data to a remote server for more accurate online monitoring and intelligent early warning of transient disturbances in the traction power supply system. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the high-order harmonic resonance monitoring and early warning device for traction substations in this application.

[0021] Figure 2 : Schematic diagram of the on-site installation and testing of the device.

[0022] Figure 3 : Schematic diagram of the internal unit of the device.

[0023] Figure 4 : Schematic diagram of the coordinated operation principle of the internal units of the device.

[0024] Figure 5 Schematic diagram of the signal preprocessing unit circuit.

[0025] Figure 6 : A schematic diagram of the device's field communication.

[0026] Figure 7 Schematic diagram of the input and output circuits for the sampling pulse synchronization signal of the acquisition unit.

[0027] Figure 8 Schematic diagram of a 16-channel analog input acquisition circuit.

[0028] Figure 9 Communication unit schematic diagram.

[0029] Figure label:

[0030] 1-Signal preprocessing unit; 11-Input signal; 12-Adjustable gain circuit; 13-Adjustable gain selection circuit; 2-Acquisition unit; 21-Voltage sensor; 22-Current sensor; 23-Data acquisition circuit; 24-AD analog-to-digital conversion circuit; 3-Data processing unit; 4-Communication unit; 5-Control unit; 6-Enclosure; 7-Remote server. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] like Figure 1-6 As shown, this embodiment provides a high-order harmonic resonance monitoring and early warning device for traction substations, including: a signal preprocessing unit 1, an acquisition unit 2, a data processing unit 3, a communication unit 4, and a control unit 5. The signal preprocessing unit 1, acquisition unit 2, data processing unit 3, communication unit 4, and control unit 5 are integrated into a housing 6. The housing 6 is equipped with wiring terminals. The voltage wiring interface of the signal preprocessing unit 1 is connected to the voltage secondary monitoring terminal of the traction substation monitoring cabinet via a probe to acquire voltage values. The current wiring interface is connected to the current secondary coil of the traction substation monitoring cabinet via a dedicated current clamp to acquire current values. After the acquisition unit 2 receives the preprocessed voltage and current waveform signals, the data processing unit 3 calculates the harmonic content and distortion rate according to existing algorithms. The data processing unit 3 is connected to the communication unit 4 via a data interface. After acquiring the voltage and current values, the data is received and transmitted to a remote server 7 via the communication unit 4. During this process, the control unit 5 controls the coordinated operation between the various units (e.g., ...). Figure 6 (As shown).

[0034] Specifically, such as Figure 3 As shown in the figure, the signal preprocessing unit 1 includes: an input signal 11, an adjustable gain circuit 12, and an adjustable gain selection circuit 13. The input signal 11 is the voltage and current waveform of the higher harmonic resonances in the traction substation, and its amplitude is amplified to varying degrees. The adjustable gain circuit 12 performs multi-stage processing on the input signal, allowing for more flexible gain amplitude control, thereby achieving a suitable sampling reference range for the AD chip. The adjustable gain selection circuit 13 provides chip select signals for different higher harmonic resonance amplitude zones, adapting to different harmonic resonance conditions.

[0035] Example 2

[0036] like Figure 4As shown, the control unit 5 acquires the input signal amplitude, acquisition error, current high-order harmonic content, and communication request from the signal processing pre-unit 1, acquisition unit 2, data processing unit 3, and communication unit 4. Based on the ADC acquisition reference voltage, it performs gain circuit selection, acquisition control, data processing control, and communication transmission. This process enables multi-level processing of the input signal, allowing for more flexible gain amplitude adjustment, thereby achieving a suitable sampling reference range for the AD chip, improving the acquisition accuracy of the acquisition unit 2, enhancing the accuracy of the data processing unit 3, and preventing misjudgments and equipment malfunctions.

[0037] Example 3

[0038] like Figure 5 As shown, the adjustable gain circuit 12 is constructed using an MCP6022-I / P inverting amplifier, containing multiple amplification levels. The inverting amplifier only contains differential-mode signals, offering stronger anti-interference capabilities and making it suitable for designing high-order harmonic resonance preprocessing circuits. Based on the signal characteristics of high-order harmonic resonance in actual traction substations, the parameters of resistors and capacitors such as R1-R6 and C1-C8 are selected to achieve targeted design. The adjustable gain selection circuit 13, based on the selection signal calculated by the control unit 5, connects to corresponding amplification circuit points A, B, C, and D, realizing multi-stage preprocessing of the input signal.

[0039] Example 4

[0040] The data processing unit 3 employs a Fourier algorithm FFT module, which utilizes the symmetry of the imaginary exponent term and other characteristics of the Fast Fourier Transform (FFT). This algorithm simplifies the calculation based on the Discrete Fourier Transform (DFT), thereby improving the solution speed for harmonic signals and further enhancing the dynamic performance of the device.

[0041] After calculating the harmonic components of the traction substation voltage using the FFT algorithm, the voltage content of the h-th harmonic is HRU. h The calculation is as follows (see GB / T14549-1993):

[0042]

[0043] In the above formula, U h U1 is the root mean square voltage (RMS) of the h-th harmonic, in units of (V); U2 is the fundamental voltage (RMS), in units of (V).

[0044] Similarly, the h-th harmonic current content HRI can be obtained. h (See GB / T14549-1993):

[0045]

[0046] In the above formula, Ih Ih is the h-th harmonic current (root mean square value), in A; I1 is the fundamental current (root mean square value), in A.

[0047] The total harmonic distortion (THD) of voltage and the total harmonic distortion (THD) of current are defined as the ratio of the square root of the sum of the squares of the harmonic components of AC voltage and current to the fundamental component, multiplied by 100%. The specific calculation formulas are as follows (see GB / T14549-1993):

[0048]

[0049] After receiving the data from the acquisition unit 2, the data processing unit 3 uses existing algorithms to obtain the corresponding voltage waveform, current waveform, voltage harmonic components, and current harmonic components.

[0050] Example 5

[0051] like Figure 4 As shown, in this embodiment, the signal preprocessing unit 1 has a multi-level adjustable gain function, the acquisition unit 2 adopts a multi-channel voltage acquisition unit and a multi-channel current acquisition unit, and the control unit 5 is connected to the remote server 7 through a built-in GPS positioning device. The control unit 5 sends real-time data to the remote server 7 according to the configured transmission time interval. On the remote server 7, the current sampled values ​​and status of the system can be viewed in real time through remote software, realizing wide-area synchronization under high-precision detection.

Claims

1. A high-order harmonic resonance monitoring and early warning device for traction substations, characterized in that, The device includes a signal preprocessing unit (1), an acquisition unit (2), a data processing unit (3), a communication unit (4), and a control unit (5); the signal preprocessing unit (1), the acquisition unit (2), the data processing unit (3), and the communication unit (4) are connected in sequence, and the control unit (5) is connected to the signal preprocessing unit (1), the acquisition unit (2), the data processing unit (3), and the communication unit (4) respectively and is used to control the coordinated work between the units; The signal preprocessing unit (1) is used to process the input signal (11) of the voltage and current waveform of the high-order harmonic resonance of the traction substation to achieve a suitable sampling reference range for the acquisition unit (2). The acquisition unit (2) is used to realize real-time online monitoring and acquisition of voltage and current signals; The data processing unit (3) uses the existing FFT algorithm to calculate the harmonic voltage content rate and harmonic current content rate respectively, and then calculates the total harmonic distortion rate of voltage and the total harmonic distortion rate of current. The communication unit (4) transmits the total harmonic distortion of voltage and total harmonic distortion of current obtained by the data processing unit (3) to the remote server (7) via wireless communication.

2. The traction substation high-order harmonic resonance monitoring and early warning device according to claim 1, characterized in that: The signal preprocessing unit (1) includes an adjustable gain circuit (12), which processes the input signal (11) of the voltage and current waveform of the high-order harmonic resonance of the traction substation to achieve a suitable sampling reference range for the acquisition unit (2).

3. The traction substation high-order harmonic resonance monitoring and early warning device according to claim 2, characterized in that: The signal preprocessing unit (1) further includes an adjustable gain selection circuit (13) connected to the adjustable gain circuit (12); the adjustable gain selection circuit (13) is used to select an appropriate gain multiple for amplitude partitioning of different higher harmonic resonances to adapt to different harmonic resonance conditions.

4. The traction substation high-order harmonic resonance monitoring and early warning device according to claim 1, characterized in that: The acquisition unit (2) includes a voltage sensor (21), a current sensor (22), a data acquisition circuit (23), and an AD analog-to-digital converter circuit (24). The voltage sensor (21) is used to detect voltage signals, the current sensor (22) is used to detect current signals, and the data acquisition circuit (23) is connected to the voltage sensor (21) and the current sensor (22) to realize real-time online monitoring and acquisition of voltage and current signals. The AD analog-to-digital converter circuit (24) is connected to the data acquisition circuit (23) and the data processing unit (3) to perform high-precision conversion between analog and digital quantities.

5. The traction substation high-order harmonic resonance monitoring and early warning device according to claim 1, characterized in that: It also includes a housing (6), a signal preprocessing unit (1), an acquisition unit (2), a data processing unit (3), a communication unit (4), and a control unit (5) integrated within the housing (6).

6. The traction substation high-order harmonic resonance monitoring and early warning device according to claim 1, characterized in that: The signal preprocessing unit (1) is connected to the secondary monitoring terminal of the voltage transformer of the traction substation monitoring cabinet through a probe, and to the secondary coil of the current transformer of the traction substation monitoring cabinet through a special current clamp.

7. The traction substation high-order harmonic resonance monitoring and early warning device according to claim 1, characterized in that: The acquisition unit (2) has a multi-channel acquisition function, and each channel acquires the voltage or current data of one branch.

8. The traction substation high-order harmonic resonance monitoring and early warning device according to claim 7, characterized in that: The acquisition unit (2) includes 16 signal monitoring terminals for acquiring 8 voltage signals and 8 current signals.

9. The traction substation high-order harmonic resonance monitoring and early warning device according to claim 1, characterized in that, The control unit (5) also integrates a GPS positioning device and a data storage circuit; the GPS positioning device is used to provide wide-area synchronous measurement of the position parameters of multiple traction substations; the data storage circuit is used to uniformly store the harmonic components of the voltage and current of the traction substations obtained by this device, as well as the total harmonic distortion rate and the waveform data of the voltage and current.

10. The traction substation high-order harmonic resonance monitoring and early warning device according to claim 5, characterized in that: The housing (6) is equipped with wiring terminals.

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