Transformer comprehensive loss measurement system and method based on SF6 gas insulation and multi-range integration

Abstract

The invention discloses a transformer comprehensive loss measurement system and method based on SF6 gas insulation and multi-range integration, and the system comprises a three-phase independent high-voltage measurement unit, a data collection unit, an AD conversion module, a signal preprocessing unit, a calculation module, a data caching unit, a communication interface, a data uploading and display unit, and a control host. The method comprises the following steps: firstly, collecting signals, then carrying out AD conversion, then carrying out harmonic filtering, and then carrying out a calculation process; then storing the data; and then the stored data is transmitted to the control host, and then real-time waveform display and report output are performed, so that the contradiction between wide range and high precision is fundamentally solved, field interference and overvoltage impact can be effectively resisted, and the test efficiency and the automation level are greatly improved. And the safety risk caused by manual operation in a high-voltage area is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to a transformer comprehensive loss measurement system and method based on SF6 gas insulation and multi-range integration. BACKGROUND

[0002] In the power equipment manufacturing and testing industry, accurate evaluation of transformer energy efficiency is crucial, which relies on high-precision measurement of no-load loss and load loss. The current mainstream measurement scheme has significant bottlenecks. The traditional method uses independent high-voltage capacitor voltage divider and current transformer, and transmits analog signals to the remote power analyzer through long cables. This system is easily disturbed by the complex electromagnetic environment on site, and the signal attenuation and phase angle error caused by long-distance analog transmission cannot be ignored. Especially when measuring low power factor parameters such as no-load loss, small phase angle errors can cause large power calculation deviations. Although existing technical solutions attempt to integrate sensing and digitizing units to improve anti-interference performance, it is still difficult to maintain optimal measurement accuracy throughout the extremely wide range from milliamperes of no-load current to kiloamperes of load current. Moreover, the system's intelligence and data management capabilities are often insufficient.

[0003] In summary, the existing technology mainly faces several key problems: First, a single current sensing technology cannot maintain the highest measurement accuracy in the extremely wide range from 0.5A to 4000A, resulting in a relatively large error when measuring small currents. Second, the system architecture relying on long-distance analog signal transmission has insufficient stability and anti-interference ability, and the measurement data is easily disturbed. Third, the system has low automation and intelligence, and the range switching often relies on manual intervention, the testing process is cumbersome, and the data management is isolated, which cannot meet the needs of modern intelligent factories for real-time uploading and online analysis of test data. Finally, the on-site calibration of integrated systems is often inconvenient, making it difficult to perform regular value traceability, affecting the long-term credibility of the measurement results. SUMMARY

[0004] The purpose of the present application is to overcome the deficiencies in the prior art and provide a transformer comprehensive loss measurement system and method based on SF6 gas insulation and multi-range integration.

[0005] To achieve the above purpose, the present application is realized by the following technical solutions: A transformer integrated loss measurement system based on SF6 gas insulation and multi-range integration includes a three-phase independent high-voltage measurement unit, a data acquisition unit, an AD conversion module, a signal preprocessing unit, a calculation module, a data buffer unit, a communication interface, a data upload and display unit, and a control host. The three-phase independent high-voltage measurement unit is connected to the high-voltage side circuit of the transformer under test. The data acquisition unit is connected to the three-phase independent high-voltage measurement unit and to the signal preprocessing unit. The signal preprocessing unit is connected to the data buffer unit via the calculation module. The data buffer unit is connected to the data upload and display unit via the communication interface, which is connected to the control host. The data upload and display unit is used to upload data to the State Grid database and display data. Each phase's high-voltage measurement unit includes two current transformer groups, a standard electronic voltage divider, and a housing. The two current transformer groups are arranged side-by-side and fixed at the top inside the housing. The standard electronic voltage divider is fixed at the bottom inside the housing. The housing is filled with SF6 gas.

[0006] Preferably, the current transformer group includes a small current sensor and a large current sensor. The small current sensor is used to measure currents from 0.5A to 400A, and the large current sensor is used to measure currents from 400A to 4000A.

[0007] Preferably, a standard electronic voltage divider includes a high-voltage standard capacitor and a low-voltage electronic arm.

[0008] Preferably, the data acquisition unit is used to acquire analog voltage signals, analog current signals, and analog frequency signals.

[0009] Preferably, the calculation module includes a voltage and current RMS value calculation unit, a power calculation unit, a loss calculation unit, and a power factor and frequency analysis unit.

[0010] A method for measuring the overall loss of transformers based on SF6 gas insulation and multi-range integration includes the following steps: Step 1: The data acquisition unit is used to acquire voltage signals, current signals, and frequency signals; Step 2: The acquired analog voltage signal, analog current signal, and analog frequency signal are converted into digital voltage signal, digital current signal, and digital frequency signal by the AD conversion module. Step 3: The signal preprocessing unit performs harmonic filtering on the digital voltage signal, digital current signal, and digital frequency signal to obtain the filtered voltage value, current value, and frequency value. Step 4: The voltage and current RMS value calculation unit performs the voltage and current RMS value calculation process, the power calculation unit performs the power calculation process, the loss calculation unit performs the loss calculation process, and the power factor and frequency analysis unit performs the power factor and frequency calculation process. Step 5: The data caching unit stores the data calculated by the voltage and current RMS value calculation unit, power calculation unit, loss calculation unit, power factor and frequency analysis unit; Step 6: The communication interface transmits the stored data to the control host; Step 7: The data upload and display unit performs real-time waveform display and report output.

[0011] As a preferred method, the calculation process for the effective values ​​of voltage and current includes the following steps: Step a1: Collect N discrete sample values, wherein the N discrete sample values ​​are voltage values. ... and current value ... N is a natural number, and N≥1024; Step a2: Calculate the effective value of voltage U and the effective value of current I. The effective value of the voltage: ; The effective value of the current: .

[0012] Accuracy specifications for voltage RMS value U and current RMS value: 0.01% of reading + 0.03% of range (number of sampling points N≥1024, ensuring harmonic coverage).

[0013] The power calculation process includes the following steps: Step b1: Based on the synchronously sampled instantaneous voltage value u(t) and instantaneous current value i(t); Step b2: Calculate the instantaneous power u(t)×i(t) by multiplying the points one by one; Step b3: Calculate the active power P. The T is the sampling period. Step b4: Calculate apparent power (S). Where S = U × I, U is the effective value of voltage, and I is the effective value of current; Step b5: Calculate reactive power ( ), .

[0014] Reactive power accuracy specification: (error ≤ 0.03%S when cosφ=0 (synchronous sampling ensures phase consistency).

[0015] As a preferred embodiment, the loss calculation process includes the following steps: Step c1: Measure the phase angle error of the standard electronic voltage divider (21). Phase angle error of the two current transformer groups , Step c2: Calculate the actual phase difference φ. The This represents the true phase difference; Step c3: Calculate the total power loss , 。

[0016] As a preferred embodiment, the power factor and frequency calculation process includes the following steps: Step d1: Calculate the power factor cosφ (including positive / negative judgment, reflecting inductive / capacitive). cosφ ranges from 0.005 to 1.000, with a resolution of 0.001.

[0017] Step d2: Calculate the time interval T0 between adjacent frequency sampling points; Step d3: Calculate the frequency f, where f is the reciprocal of the period; The N is the number of periodic sampling points, and t k For the kth sampling time.

[0018] The beneficial effects of this invention are as follows: The current transformer group includes independent dual current transformers (CTs) with small current sensors and large current sensors. The small current sensors are used to measure currents from 0.5A to 400A, and the large current sensors are used to measure currents from 400A to 4000A. This fundamentally solves the contradiction between wide measurement range and high precision, ensuring accurate measurement across the entire range from small no-load current to huge load current. Even under the harsh condition of a power factor as low as 0.008, the loss measurement accuracy can still be better than ±1.15%, ensuring that the current can achieve an ultra-high precision close to 0.01 level throughout the entire measurement range. The standard electronic voltage divider consists of a high-voltage standard capacitor and a low-voltage electronic arm, and it has excellent linearity and low angle error over the entire range of 10V to 150kV. The casing is filled with SF6 gas, which gives the system excellent electromagnetic compatibility and electrical insulation strength, effectively resisting on-site interference and overvoltage impact, and ensuring the safe and stable operation of the system and the transformer under test. By remotely switching between small and large current sensors via the host control, the current range can be switched, which greatly improves testing efficiency and automation level, and eliminates the safety risks caused by manual operation in high-voltage areas. The integration of real-time data upload to the State Grid database is more in-depth, and the calibration design is more convenient, forming a complete solution covering accurate measurement, intelligent analysis, data management and convenient traceability, demonstrating stronger engineering practicality and comprehensive competitive advantages. Attached Figure Description

[0019] Figure 1 This is a module connection diagram of the present invention; Figure 2 This is a schematic diagram of the high-voltage measurement unit. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings: like Figure 1 , Figure 2 As shown, the transformer integrated loss measurement system based on SF6 gas insulation and multi-range integration includes a three-phase independent high-voltage measurement unit 2, a data acquisition unit 3, an AD conversion module, a signal preprocessing unit 4, a calculation module 5, a data buffer unit 6, a communication interface 7, a data upload and display unit 9, and a control host 8. The three-phase independent high-voltage measurement unit 2 is connected to the high-voltage side circuit 1 of the transformer under test. The data acquisition unit 3 is connected to the three-phase independent high-voltage measurement unit 2 and the signal preprocessing unit 4. The signal preprocessing unit 4 communicates with the calculation module 5. A data buffer unit 6 is connected, which is connected to a data upload and display unit 9 via a communication interface 7. The communication interface 7 is connected to a control host 8. The data upload and display unit 9 is used to upload data to the State Grid database and display data. The high-voltage measurement unit for each phase includes two current transformer groups, a standard electronic voltage divider 21, and a housing 24. The two current transformer groups are arranged side by side and are fixed at the top inside the housing 24. The standard electronic voltage divider 21 is fixed at the bottom inside the housing 24. The housing 24 is filled with SF6 gas.

[0021] like Figure 1 , Figure 2 As shown, the current transformer group includes a small current sensor 22 and a large current sensor 23. The small current sensor 22 is used to measure currents from 0.5A to 400A, and the large current sensor 23 is used to measure currents from 400A to 4000A. The standard electronic voltage divider 21 includes a high-voltage standard capacitor 211 and a low-voltage electronic arm 212.

[0022] like Figure 1As shown, data acquisition unit 3 is used to acquire analog voltage signals, analog current signals, and analog frequency signals. Calculation module 5 includes an RMS voltage and current calculation unit 51, a power calculation unit 52, a loss calculation unit 53, and a power factor and frequency analysis unit 54.

[0023] A method for measuring the overall loss of transformers based on SF6 gas insulation and multi-range integration includes the following steps: Step 1: The data acquisition unit 3 is used to acquire voltage signals, current signals, and frequency signals; Step 2: The acquired analog voltage signal, analog current signal, and analog frequency signal are converted into digital voltage signal, digital current signal, and digital frequency signal by the AD conversion module. Step 3: The signal preprocessing unit 4 performs harmonic filtering on the voltage digital signal, current digital signal, and frequency digital signal to obtain the filtered voltage value, current value, and frequency value. Step 4: The voltage and current RMS value calculation unit 51 performs the voltage and current RMS value calculation process, the power calculation unit 52 performs the power calculation process, the loss calculation unit 53 performs the loss calculation process, and the power factor and frequency analysis unit 54 performs the power factor and frequency calculation process. Step 5: The data caching unit 6 stores the data calculated by the voltage and current RMS value calculation unit 51, the power calculation unit 52, the loss calculation unit 53, and the power factor and frequency analysis unit 54; Step 6: Communication interface 7 transmits the stored data to the control host 8; Step 7: Data upload and display unit 9 performs real-time waveform display and report output.

[0024] The calculation process for the effective values ​​of voltage and current includes the following steps: Step a1: Collect N discrete sample values, wherein the N discrete sample values ​​are voltage values. ... and current value ... N is a natural number, and N≥1024; Step a2: Calculate the effective value of voltage U and the effective value of current I. The effective value of the voltage: ; The effective value of the current: .

[0025] The power calculation process includes the following steps: Step b1: Based on the synchronously sampled instantaneous voltage value u(t) and instantaneous current value i(t); Step b2: Calculate the instantaneous power u(t)×i(t) by multiplying the points one by one; Step b3: Calculate the active power P. The T is the sampling period. Step b4: Calculate apparent power (S). Where S = U × I, U is the effective value of voltage, and I is the effective value of current; Step b5: Calculate reactive power ( ), .

[0026] As a preferred embodiment, the loss calculation process includes the following steps: Step c1: Measure the phase angle error of the standard electronic voltage divider (21). Phase angle error of the two current transformer groups , Step c2: Calculate the actual phase difference φ. The This represents the true phase difference; Step c3: Calculate the total power loss , 。

[0027] As a preferred embodiment, the power factor and frequency calculation process includes the following steps: Step d1: Calculate the power factor cosφ. ; Step d2: Calculate the time interval T0 between adjacent frequency sampling points; Step d3: Calculate the frequency f, where f is the reciprocal of the period; The N is the number of periodic sampling points, and t k For the kth sampling time.

[0028] This invention acquires voltage, current, and frequency signals from the high-voltage side of the transformer using a three-phase independent high-voltage measurement unit (SF6 insulation, dual-range current transformer + voltage divider). After AD conversion and signal preprocessing, the calculation module performs calculations on the effective value, power, loss, power factor, and frequency. The data is buffered and transmitted to the control host via a communication interface. Finally, the data unit displays the data, outputs reports, and uploads the data to the State Grid database. The core technology is to achieve high-precision measurement of transformer losses and electrical parameters through a wide-range current transformer and digital processing.

[0029] High measurement accuracy Synchronous sampling technology is adopted, along with phase angle error correction, to reduce system errors caused by transformers and voltage dividers.

[0030] The number of sampling points is ≥1024, covering harmonic components, ensuring the accuracy of calculations for parameters such as RMS value and power.

[0031] 2. Wide measurement range coverage Dual-range current sensor (0.5A~400A, 400A~4000A) is suitable for current measurement needs under different load conditions.

[0032] The standard electronic voltage divider features a wide bandwidth design (DC-10MHz) and is compatible with a variety of voltage and frequency signals.

[0033] 3. Strong safety and stability The high-voltage measurement unit is filled with SF6 gas, which has excellent insulation properties and avoids the risk of high-voltage breakdown.

[0034] The three-phase independent measurement design reduces phase-to-phase interference and improves operational stability under complex operating conditions.

[0035] 4. High practicality and integration It integrates signal acquisition, conversion, calculation, storage, transmission and display into one unit, with a closed-loop process that requires no additional equipment.

[0036] It supports real-time waveform display, report output, and uploading to the State Grid database, adapting to the data management needs of the power system.

[0037] The current transformer group includes independent dual current transformers (CTs) with small current sensors and large current sensors. The small current sensors are used to measure currents from 0.5A to 400A, while the large current sensors are used to measure currents from 400A to 4000A. This fundamentally solves the contradiction between wide measurement range and high precision, ensuring accurate measurement across the entire range from small no-load currents to huge load currents. Even under the stringent condition of a power factor as low as 0.008, the loss measurement accuracy can still be better than ±1.15%, ensuring that the current can achieve an ultra-high precision close to 0.01% throughout the entire measurement range.

[0038] It should be noted that the above examples are merely one specific embodiment of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. In short, all variations that can be directly derived or conceived by those skilled in the art from the content disclosed in this invention should be considered within the scope of protection of this invention.

Claims

1. A transformer comprehensive loss measurement system based on SF6 gas insulation and multi-range integration, characterized in that, The system includes a three-phase independent high-voltage measurement unit (2), a data acquisition unit (3), an AD conversion module, a signal preprocessing unit (4), a calculation module (5), a data buffer unit (6), a communication interface (7), a data upload and display unit (9), and a control host (8). The three-phase independent high-voltage measurement unit (2) is connected to the high-voltage side circuit (1) of the transformer under test. The data acquisition unit (3) is connected to the three-phase independent high-voltage measurement unit (2). The data acquisition unit (3) is connected to the signal preprocessing unit (4). The signal preprocessing unit (4) is connected to the data buffer unit (6) through the calculation module (5). The data caching unit (6) is connected to the data upload and display unit (9) through the communication interface (7). The communication interface (7) is connected to the control host (8). The data upload and display unit (9) is used to upload data to the State Grid database and display data. The high voltage measurement unit of each phase includes two current transformer groups, a standard electronic voltage divider (21), and a housing (24). The two current transformer groups are arranged side by side and are fixed in the upper part of the housing (24). The standard electronic voltage divider (21) is fixed in the lower part of the housing (24). The housing (24) is filled with SF6 gas.

2. The transformer comprehensive loss measurement system based on SF6 gas insulation and multi-range integration as described in claim 1, characterized in that, The current transformer group includes a small current sensor (22) and a large current sensor (23). The small current sensor (22) is used to measure current from 0.5A to 400A, and the large current sensor (23) is used to measure current from 400A to 4000A.

3. The transformer comprehensive loss measurement system based on SF6 gas insulation and multi-range integration as described in claim 1, characterized in that, The standard electronic voltage divider (21) includes a high-voltage standard capacitor (211) and a low-voltage electronic arm (212).

4. The transformer comprehensive loss measurement system based on SF6 gas insulation and multi-range integration as described in claim 1, characterized in that, The data acquisition unit (3) is used to acquire voltage analog signals, current analog signals, and frequency analog signals.

5. The transformer comprehensive loss measurement system based on SF6 gas insulation and multi-range integration according to claim 1, characterized in that, The calculation module (5) includes a voltage and current effective value calculation unit (51), a power calculation unit (52), a loss calculation unit (53), and a power factor and frequency analysis unit (54).

6. A method for measuring the comprehensive loss of a transformer based on SF6 gas insulation and multi-range integration, based on the transformer comprehensive loss measurement system based on SF6 gas insulation and multi-range integration as described in claims 1 to 5, characterized in that... Includes the following steps: Step 1: The data acquisition unit (3) is used to acquire voltage signals, current signals, and frequency signals; Step 2: The acquired analog voltage signal, analog current signal, and analog frequency signal are converted into digital voltage signal, digital current signal, and digital frequency signal by the AD conversion module. Step 3: The signal preprocessing unit (4) performs harmonic filtering on the voltage digital signal, current digital signal, and frequency digital signal to obtain the filtered voltage value, current value, and frequency value. Step 4: The voltage and current effective value calculation unit (51) performs the voltage and current effective value calculation process, the power calculation unit (52) performs the power calculation process, the loss calculation unit (53) performs the loss calculation process, and the power factor and frequency analysis unit (54) performs the power factor and frequency calculation process. Step 5: The data caching unit (6) stores the data calculated by the voltage and current RMS value calculation unit (51), power calculation unit (52), loss calculation unit (53), and power factor and frequency analysis unit (54); Step 6: The communication interface (7) transmits the stored data to the control host (8); Step 7: The data upload and display unit (9) performs real-time waveform display and report output.

7. The method for measuring the comprehensive loss of a transformer based on SF6 gas insulation and multi-range integration as described in claim 6, characterized in that, The calculation process for the effective values ​​of voltage and current includes the following steps: Step a1: Collect N discrete sample values, wherein the N discrete sample values ​​are voltage values. ... and current value ... N is a natural number, and N≥1024; Step a2: Calculate the effective value of voltage U and the effective value of current I. The effective value of the voltage: ; The effective value of the current: .

8. The method for measuring the comprehensive loss of a transformer based on SF6 gas insulation and multi-range integration as described in claim 7, characterized in that, The power calculation process includes the following steps: Step b1: Based on the synchronously sampled instantaneous voltage value u(t) and instantaneous current value i(t); Step b2: Calculate the instantaneous power u(t)×i(t) by multiplying the points one by one; Step b3: Calculate the active power P. The T is the sampling period; Step b4: Calculate apparent power (S). S = U × I, where U is the effective value of voltage and I is the effective value of current; Step b5: Calculate reactive power ( ), 。 9. The method for measuring the comprehensive loss of a transformer based on SF6 gas insulation and multi-range integration as described in claim 8, characterized in that, The loss calculation process includes the following steps: Step c1: Measure the phase angle error of the standard electronic voltage divider (21). Phase angle error of the two current transformer groups , Step c2: Calculate the actual phase difference φ. The This represents the true phase difference; Step c3: Calculate the total power loss , 。 10. The method for measuring the comprehensive loss of a transformer based on SF6 gas insulation and multi-range integration according to claim 9, characterized in that, The power factor and frequency calculation process includes the following steps: Step d1: Calculate the power factor cosφ. ; Step d2: Calculate the time interval T0 between adjacent frequency sampling points; Step d3: Calculate the frequency f, where f is the reciprocal of the period; The N is the number of periodic sampling points, and t k For the kth sampling time.

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