Balun MMIC power amplifier, broadband test device and broadband test method

Abstract

The invention relates to a balun MMIC power amplifier, a broadband testing device and a broadband testing method.The balun MMIC power amplifier comprises a 1: 1 balun differential circuit, an MMIC power amplifier body and a 1: K balun differential circuit, and the problem of high-frequency current signal amplification is solved; the broadband testing method comprises the following steps: carrying out steady-state wave testing on the current transformer to be tested through the broadband testing device; carrying out transient wave testing on the current transformer to be tested through the broadband testing device; and testing the traveling wave positioning function of the current transformer based on the traveling wave head, testing the accuracy of the traveling wave fault positioning function of the current transformer to be tested, and generating a traveling wave positioning function test report. Based on the application of a Balun MMIC power amplifier and the optimization of a test process, the invention aims to solve the key problems in the prior art, improve the accuracy and comprehensiveness of the broadband test of the current transformer, and meet the urgent demand of a power system for the accurate evaluation of the performance of the current transformer.

Description

Technical Field

[0001] The present invention relates to the technical field of current transformer detection, and in particular to a balun MMIC power amplifier, a broadband testing device, and a broadband testing method. Background Art

[0002] With the gradual maturity of technologies related to traveling wave signal extraction, high-speed data acquisition, and data transmission, a variety of traveling wave fault location systems have been successfully developed, and numerous traveling wave fault location devices have been put into practical operation both domestically and internationally. However, traveling wave fault location devices require a sufficiently wide bandwidth to accurately capture the high-frequency components of the traveling wave signal. Traveling wave signals contain abundant high-frequency information during faults (typically ranging from tens of kHz to MHz). If the bandwidth of a traveling wave fault location device is insufficient, some high-frequency details will be lost, affecting distance measurement accuracy. Furthermore, traveling wave fault location devices must have a good amplitude to ensure minimal amplitude distortion of the traveling wave signal across the entire operating frequency band. However, existing wideband testing devices for traveling wave current transformers have numerous shortcomings.

[0003] First, in terms of high-frequency current detection, because the high-frequency current signals generated by existing high-frequency testing equipment are extremely weak, the current transformer will have large errors in re-collection. This leads to large errors when evaluating the response characteristics of the current transformer to high-frequency signals. Existing testing equipment is unable to accurately capture the characteristics of the high-frequency current generated in some transient processes, resulting in inaccurate performance evaluation of the current transformer under these transient conditions. This inaccurate evaluation may cause the current transformer to fail to operate normally when similar transient high-frequency current conditions occur during actual power system operation, affecting the safe and stable operation of the power system.

[0004] Secondly, the existing traveling wave current transformer testing process is incomplete. The traditional testing process mainly focuses on the test of steady-state waveforms and ignores the characteristics of transient waves. However, in actual power systems, the occurrence of traveling wave faults is often accompanied by the generation of transient waves. Evaluating the performance of current transformers based solely on steady-state waveform test results cannot fully understand their performance under actual fault conditions. For example, when a traveling wave fault occurs in the power system, the response characteristics of the current transformer to transient waves directly affect the accuracy of fault location. If the test process lacks transient wave testing, it will be impossible to screen out current transformers that are truly suitable for traveling wave fault locating devices, thereby reducing the accuracy and reliability of traveling wave fault locating, and bringing difficulties to fault detection and repair of power systems.

[0005] In summary, the weak high-frequency signal output by existing broadband test devices changes after being amplified by traditional amplifiers, causing the key characteristic amplitude and phase of the signal to change, making it impossible to truly reflect the performance of the current transformer at this frequency. The traditional test process lacks testing of transient waves, resulting in the inability to screen out current transformers that are truly suitable for traveling wave fault locating devices, which greatly reduces the accuracy and reliability of traveling wave fault locating, and increases the difficulty and time cost of power system fault troubleshooting and repair. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a balun MMIC power amplifier, a broadband test device and a broadband test method to overcome the deficiencies in the above-mentioned prior art.

[0007] The present invention solves the above-mentioned technical problem with the following technical solution: a balun MMIC power amplifier, comprising a 1:1 balun differential circuit, an MMIC power amplifier, and a 1:K balun differential circuit, wherein the 1:1 balun differential circuit and the 1:K balun differential circuit are respectively connected to the differential input terminal and the differential output terminal of the MMIC power amplifier; 1:1 balun differential circuit, which is used to convert the weak high-frequency current signal generated by the signal generating module of the input broadband test device into a balanced differential signal, and the input and output signal amplitude ratio is 1:1; An MMIC power amplifier is used to perform high-gain amplification on the differential signal obtained after processing by the 1:1 balun differential circuit; 1: K balun differential circuit, which is used to optimize the balance-unbalance characteristics of the signal after high-gain amplification by the MMIC power amplifier, and adjust the signal amplitude through its special ratio structure.

[0008] The beneficial effects of the present invention are as follows: The 1:1 balun reduces common-mode interference to a certain extent through its structural characteristics. This conversion and suppression provides a better anti-interference foundation for signals entering subsequent circuits, while the conversion into a differential signal is more suitable for the differential signal processing requirements of MMIC power amplifiers.

[0009] The low-noise characteristics of MMIC power amplifiers ensure that signals are amplified with relatively low noise. In the 1-megahertz high frequency band, they can increase signal amplitude by tens or even hundreds of times while maintaining a low noise figure, ensuring that the amplified signal has both sufficient strength and high purity.

[0010] The 1:K differential balun circuit, through its unique structure and electromagnetic induction principle, further suppresses these common-mode interferences to extremely low levels, while further improving the differential signal's interference immunity and signal integrity. After processing through the second 1:K differential balun circuit, the differential signal becomes a higher-quality, amplitude-adapted excitation signal that can be input into the current transformer for testing.

[0011] The present invention combines an MMIC power amplifier with two balun differential circuits to form a new power amplifier to solve the problem of high-frequency current signal amplification.

[0012] On the basis of the above technical solution, the present invention can also be improved as follows.

[0013] Furthermore, the 1:1 balun differential circuit includes an inductor L1, a capacitor C1, a capacitor C2, and a resistor R1; A first end of the inductor L1 is connected to the RF input terminal, a second end of the inductor L1 is connected to a first end of the capacitor C1, a first end of the resistor R1, and a first end of the capacitor C2, a second end of the capacitor C1 is connected to the differential output terminal, a second end of the resistor R1 is grounded, and a second end of the capacitor C2 is grounded.

[0014] Further, the 1:K balun differential circuit includes an inductor L2, a capacitor C3, a capacitor C4, and a resistor R3; A first end of the inductor L2 is connected to the differential input terminal, a second end of the inductor L2 is connected to a first end of the capacitor C3, a first end of the resistor R3, and a first end of the capacitor C4, a second end of the capacitor C4 is connected to the single-ended output terminal, a second end of the resistor R3 is grounded, and a second end of the capacitor C4 is grounded.

[0015] Furthermore, it also includes a resistor R2, the differential output end of the 1:1 balun differential circuit is connected to the first end of the resistor R2 and the differential input end of the MMIC power amplifier, the differential output end of the MMIC power amplifier is connected to the differential input end of the 1:K balun differential circuit, and the second end of the resistor R2 is grounded.

[0016] The present invention also discloses a wide-band test device based on a balun MMIC power amplifier, comprising the balun MMIC power amplifier as described above; and a wide-band test device for performing a wide-band test on a current transformer of a traveling wave fault ranging device.

[0017] The beneficial effect of the present invention is that the broadband test device of the present invention integrates an MMIC power amplifier and two balun differential circuit power amplifiers to solve the problem of high-frequency current signal amplification.

[0018] The present invention also discloses a broadband testing method based on a broadband testing device. The broadband testing device is used to perform a broadband test on a current transformer of a traveling wave fault location device. The testing method includes the following steps: Step S01: Perform a steady-state wave test on the current transformer to be tested using a broadband test device, construct an amplitude response characteristic curve to determine whether the current transformer to be tested meets the steady-state broadband characteristic. If so, proceed to the next test step. Step S02: performing a transient wave test on the current transformer to be tested using a broadband test device, analyzing the waveform similarity between the transient wave of the current transformer to be tested and the transient wave of a standard current transformer, and judging whether the current transformer to be tested is qualified based on the waveform similarity result; Step S03: Testing the traveling wave location function of the current transformer based on the traveling wave head to test the accuracy of the traveling wave fault location function of the current transformer to be tested, and generating a traveling wave location function test report.

[0019] The beneficial effects of the present invention are as follows: on the basis of the traditional steady-state waveform test, the present invention adds a transient wave test link to achieve a comprehensive evaluation of the performance of the current transformer. The system is equipped with a high-precision data acquisition module, which collects the output signal of the current transformer under transient wave excitation at an extremely high sampling frequency. The collected data is deeply analyzed through complex digital signal processing algorithms and data analysis methods to obtain the waveform similarity, traveling wave head characteristics, etc. between the current transformer to be tested and the standard current transformer under transient conditions. By analyzing these parameters, it is possible to fully understand the response capability of the current transformer to transient waves, thereby screening out current transformers that are more suitable for traveling wave fault locating devices, and improving the accuracy and reliability of traveling wave fault locating. The present invention aims to solve the key problems existing in the prior art through the application of balun MMIC power amplifiers and the optimization of the test process, improve the accuracy and comprehensiveness of broadband testing of current transformers, and meet the urgent needs of the power system for accurate evaluation of current transformer performance.

[0020] On the basis of the above technical solution, the present invention can also be improved as follows.

[0021] Furthermore, step S01 specifically includes the following steps: Step S11: On the control interface of the broadband test device, set parameters for the signal generation module. The parameter setting includes: Set the steady-state signal to be output as a sine wave signal; Set the frequency range of the steady-state signal to: start from a low frequency of 5Hz and gradually increase to a high frequency of 1MHz; Set the frequency sweep step size: 1Hz in the low frequency band and 100Hz in the high frequency band; Step S12: Calculate the amplitude-frequency response of the standard current transformer device and the current transformer to be tested using a formula. The amplitude-frequency response calculation formula is: ; Where, For the frequency The amplitude-frequency response gain at ; For the frequency The output signal amplitude of the lower current transformer; For the frequency The amplitude of the current transformer input signal; Step S13: Use the logarithm of the frequency as the horizontal axis , the logarithm of the amplitude response is used as the ordinate , respectively construct the amplitude response characteristic curves of the standard current transformer and the current transformer to be tested; Step S14: Use -3dB curve comparison, in the amplitude-frequency characteristic curve before 500KHz, when the vertical coordinate If it is lower than -3dB, it meets the steady-state broadband characteristics.

[0022] Furthermore, step S02 specifically includes the following steps: Step S21: The broadband test device and the GPS module are started. The GPS module sends a trigger signal to the signal generation module according to the set time. After receiving the trigger signal, the signal generation module and the balun MMIC power amplifier send a transient wave signal simulating a short-circuit fault to the primary side of the current transformer under test and the standard current transformer. Step S22: After the current transformer under test and the standard current transformer receive the transient wave signal simulating a short-circuit fault on the primary side, the secondary sides of the current transformer under test and the standard current transformer will sense corresponding electrical signals; the data acquisition module of the broadband test device synchronously collects the output signals of the secondary sides of the two current transformers and records the voltage or current value at each moment; Step S23: The collected transient wave data of the current transformer to be tested and the standard current transformer are transmitted to the data analysis unit. The data analysis unit uses a similarity analysis algorithm to perform similarity calculation, and judges whether the current transformer to be tested is qualified based on the calculated similarity result, and generates a similarity report.

[0023] Furthermore, the similarity analysis algorithm in step S23 includes: The algorithm based on cross-correlation function is used to calculate the discrete time series of transient wave data collected by the current transformer to be tested and the standard current transformer. and , and its cross-correlation function Defined as: ; in, is the length of the data sequence, is the time delay; if the waveform similarity ≥97%, it means that the current transformer to be tested is qualified.

[0024] Further, step S03 specifically includes: Step S31: adjusting the parameters of the signal generating module, the GPS module triggers the signal generating module according to the set time, and sends a transient wave signal containing obvious traveling wave head characteristics to the primary side of the current transformer to be tested; Step S32: The secondary side of the current transformer to be tested senses an electrical signal containing traveling wave header information, and the data acquisition module of the broadband test device acquires the electrical signal containing traveling wave header information at a high sampling frequency; Step S33: During the acquisition process, the wave head is located by wavelet transform, and the starting time of the traveling wave head is recorded; based on the collected traveling wave head data, the traveling wave location algorithm is used for analysis; Step S34: repeating the above steps multiple times, counting the deviations between the wave front interval time of the current transformer to be tested and the wave front interval time of the standard current transformer, and calculating indicators including the average deviation and the standard deviation; Step S35: If the difference between the average deviation and the standard deviation is less than 0.05us, and the maximum deviation between the wave front interval time of the current transformer to be tested and the wave front interval time of the standard current transformer is less than 0.1us, the current transformer to be tested is qualified; and a traveling wave positioning function test report is generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the overall framework diagram of the present invention; Figure 2 Schematic diagram of the power amplifier structure of the present invention; Figure 3 This is a 1:1 balun differential circuit diagram of the present invention; Figure 4 This is a circuit diagram for accessing the MMIC power amplifier of the present invention; Figure 5 1:K balun differential circuit diagram of the present invention; Figure 6 This is a schematic diagram of the current transformer broadband test platform of the present invention; Figure 7 is an amplitude response characteristic curve diagram of the present invention; Figure 8 This is a waveform similarity curve diagram of the present invention. DETAILED DESCRIPTION

[0026] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0027] like Figures 1 to 8As shown, in embodiment 1, a balun MMIC power amplifier includes a 1:1 balun differential circuit, an MMIC power amplifier and a 1:K balun differential circuit, wherein the 1:1 balun differential circuit and the 1:K balun differential circuit are respectively connected to the differential input terminal and the differential output terminal of the MMIC power amplifier; The 1:1 balun differential circuit, based on its unique winding structure and electromagnetic coupling principles, converts the weak high-frequency current signal generated by the signal generator module of the input broadband test device into a balanced differential signal with a 1:1 input-to-output signal amplitude ratio. In this process, it provides preliminary suppression of common-mode interference. Due to the complex electromagnetic environment, common-mode interference can be input along with the signal. The 1:1 balun reduces this common-mode interference to a certain extent through its structural characteristics. This conversion and suppression provides a better interference resistance foundation for signals entering subsequent circuits. Furthermore, the conversion to a differential signal is more suitable for the differential signal processing requirements of the MMIC power amplifier.

[0028] The MMIC power amplifier, utilizing compound semiconductor materials and the transistor amplification mechanism, is used to achieve high-gain amplification of the differential signal generated by the 1:1 balun differential circuit. During the amplification process, the MMIC power amplifier's low-noise characteristics ensure that the signal is amplified while introducing relatively low noise. In the high-frequency range of 1 MHz, it can increase the signal amplitude by tens or even hundreds of times while maintaining a low noise figure, ensuring that the amplified signal has both sufficient strength and high purity.

[0029] 1: K balun differential circuit, which is used to optimize the balance-unbalance characteristics of the signal after high-gain amplification by the MMIC power amplifier, and adjust the signal amplitude through its special ratio structure.

[0030] The transformation ratio here is 1:K, meaning the output signal amplitude is K times the input signal amplitude. This also suppresses new common-mode interference that may be introduced during the MMIC amplification process. In actual circuits, although MMIC power amplifiers inherently have a certain degree of interference immunity, various factors may still introduce some common-mode interference during the amplification process. The 1:K differential balun circuit, through its unique structure and electromagnetic induction principle, suppresses this common-mode interference to an extremely low level, further improving the differential signal's interference immunity and signal integrity. After processing by the second 1:K differential balun circuit, the differential signal becomes a higher-quality, amplitude-matched excitation signal, suitable for input into current transformers for testing.

[0031] The present invention combines an MMIC power amplifier with two balun differential circuits to form a new power amplifier to solve the problem of high-frequency current signal amplification.

[0032] Example 2: This example is a further improvement on Example 1, and its details are as follows: The 1:1 balun differential circuit includes inductor L1, capacitor C1, capacitor C2 and resistor R1; A first end of the inductor L1 is connected to the RF input terminal, a second end of the inductor L1 is connected to a first end of the capacitor C1, a first end of the resistor R1, and a first end of the capacitor C2, a second end of the capacitor C1 is connected to the differential output terminal, a second end of the resistor R1 is grounded, and a second end of the capacitor C2 is grounded.

[0033] See also Figure 3 , is the circuit diagram of a 1:1 balun differential circuit. The RF input is a single-ended RF signal access point. L1 (25nH) is a series inductor used for high-frequency impedance matching or filtering. C1 (0.4pF) is a parallel capacitor that forms an LC filter or matching network with L1. R1 (10Ω) is a parallel resistor used to suppress oscillation or adjust impedance. C2 (1nF) is a ground bypass capacitor for the input signal to filter out high-frequency noise. Double grounding: The signal ground and the power ground are connected separately through capacitor C2 and resistor R1 to enhance stability. This circuit converts to a differential signal through an LC network, which is suitable for driving balanced loads or suppressing common-mode interference; Center frequency , substituting L1 and C1, we get the center frequency band is about 1Mhz. When the signal is in the center frequency band, the LC network resonates, the impedance matching is optimal, the standing wave ratio is lowest, and the signal transmission efficiency is highest; In the low-frequency band (1 Hz ≤ low-frequency band < 1 MHz), L1's inductive reactance decreases as frequency decreases, while C2's capacitive reactance increases, reducing common-mode rejection. However, differential-mode signals can still be transmitted through C1. In the high-frequency band (1 MHz < high-frequency band ≤ 2 MHz), L1's inductive reactance increases, while C1's capacitive reactance decreases, making the network capacitive. High-frequency response can be extended by adjusting component parasitic parameters (such as the distributed capacitance of the inductor).

[0034] In a specific implementation, the MMIC power amplifier of the present invention adopts ADL5605 MMIC power amplifier, which is an existing chip with a gain of 23dB and a bandwidth between 10kHz and 500MHz.

[0035] Example 3: This example is a further improvement on Example 2, and its details are as follows: 1:K balun differential circuit includes inductor L2, capacitor C3, capacitor C4 and resistor R3; A first end of the inductor L2 is connected to the differential input terminal, a second end of the inductor L2 is connected to a first end of the capacitor C3, a first end of the resistor R3, and a first end of the capacitor C4, a second end of the capacitor C4 is connected to the single-ended output terminal, a second end of the resistor R3 is grounded, and a second end of the capacitor C4 is grounded.

[0036] Figure 5 This is the circuit diagram of the 1:K balun differential circuit. The 1:K balun differential circuit realizes impedance transformation and balanced-unbalanced conversion through the resonance of inductor L2 and capacitor C3. The center frequency Substituting L1 and C1, the center frequency is approximately 1 MHz. Impedance matching and transformation ratio (1:K): The balanced end impedance (differential) is Z1 = 25Ω (the matching impedance of the signal generator of the broadband test system of the present invention is 25Ω), and the unbalanced end target impedance is Z2 = 50Ω. According to the impedance transformation formula Z2 = K2 * Z1, we can obtain: (The K value can be changed by changing the R3 value).

[0037] The first 1:1 balun differential circuit converts the single-ended signal into a differential signal and suppresses common-mode interference, reducing the effects of interference on the MMIC power amplifier during amplification. The signal noise after common-mode interference suppression is lower, helping the MMIC power amplifier leverage its high gain and low noise advantages and improving amplification efficiency. Furthermore, the 1:1 transformation ratio ensures signal amplitude consistency during the conversion process, allowing the MMIC power amplifier to amplify according to its design characteristics. The MMIC power amplifier performs high-gain amplification on the signal processed by the first 1:1 balun, resolving the gain issue during high-frequency signal amplification and providing a signal of sufficient strength for subsequent 1:K balun processing. Only a signal of sufficient strength can achieve the appropriate amplitude after 1:K balun processing through transformation ratio adjustment while maintaining good signal characteristics for accurate current transformer excitation testing. This collaborative approach, comprised of a 1:1 balun differential circuit, an MMIC power amplifier, and a 1:K balun differential circuit, fully leverages the strengths of each component, improving the overall test system's ability to process high-frequency current signals while also enhancing its stability and reliability in complex electromagnetic environments. This enables the new power amplifier to amplify high-frequency current signals while effectively maintaining their authenticity and integrity, meeting the stringent high-frequency signal processing standards for broadband current transformer testing.

[0038] Example 4: This example is a further improvement on Example 3, and its details are as follows: It also includes a resistor R2, the differential output end of the 1:1 balun differential circuit is connected to the first end of the resistor R2 and the differential input end of the MMIC power amplifier, the differential output end of the MMIC power amplifier is connected to the differential input end of the 1:K balun differential circuit, and the second end of the resistor R2 is grounded.

[0039] Example 5, a wideband test device based on a balun MMIC power amplifier, comprising the balun MMIC power amplifier of any one of Examples 1 to 4; and a wideband test device for performing wideband testing on a current transformer in a traveling wave fault location device. The wideband test device of the present invention integrates an MMIC power amplifier and two power amplifiers using balun differential circuits to address the challenge of amplifying high-frequency current signals.

[0040] Example 6, a broadband testing method based on a broadband testing device, uses the broadband testing device of Example 5 to perform a broadband test on a current transformer of a traveling wave fault location device. The testing method includes the following steps: The present invention proposes to evaluate the broadband characteristics of the current transformer by using steady-state signal experiments and transient signal comprehensive tests; Step S01: Perform a steady-state wave test on the current transformer to be tested using a broadband test device, construct an amplitude response characteristic curve to determine whether the current transformer to be tested meets the steady-state broadband characteristic. If so, proceed to the next test step. The broadband test device can generate high-frequency and high-amplitude transient waves of any form through a signal generator and a balun MMIC power amplifier. Based on this characteristic, transient signal testing can be performed after the steady-state broadband characteristic is met. Step S02: performing a transient wave test on the current transformer to be tested using a broadband test device, analyzing the waveform similarity between the transient wave of the current transformer to be tested and the transient wave of a standard current transformer, and judging whether the current transformer to be tested is qualified based on the waveform similarity result; Step S03: Testing the traveling wave location function of the current transformer based on the traveling wave head to test the accuracy of the traveling wave fault location function of the current transformer to be tested, and generating a traveling wave location function test report.

[0041] Based on the traditional steady-state waveform test, the present invention adds a transient wave test link to achieve a comprehensive evaluation of the performance of the current transformer. The system is equipped with a high-precision data acquisition module, which collects the output signal of the current transformer under transient wave excitation at an extremely high sampling frequency. The collected data is deeply analyzed through complex digital signal processing algorithms and data analysis methods to obtain the waveform similarity, traveling wave head characteristics, etc. between the current transformer under transient conditions and the standard current transformer. By analyzing these parameters, the response ability of the current transformer to transient waves can be fully understood, thereby screening out current transformers that are more suitable for traveling wave fault locating devices, and improving the accuracy and reliability of traveling wave fault locating.

[0042] In summary, the present invention aims to solve the key problems existing in the prior art through the application of balun MMIC power amplifier and optimization of the test process, improve the accuracy and comprehensiveness of current transformer broadband testing, and meet the urgent needs of the power system for accurate evaluation of current transformer performance.

[0043] Example 7: This example is a further improvement on Example 6, and its details are as follows: Step S01 specifically includes the following steps: Step S11: On the control interface of the broadband test device, set parameters for the signal generation module. The parameter setting includes: Set the steady-state signal to be output as a sine wave signal; Set the frequency range of the steady-state signal to: start from a low frequency of 5Hz and gradually increase to a high frequency of 1MHz; Set the frequency sweep step size: 1 Hz in the low frequency band and 100 Hz in the high frequency band to ensure that more accurate test data can be obtained in different frequency bands.

[0044] Step S12: Calculate the amplitude-frequency response of the standard current transformer and the current transformer to be tested using a formula. The amplitude-frequency response calculation formula is: ; Where, For the frequency The amplitude-frequency response gain at ; For the frequency The output signal amplitude of the lower current transformer; For the frequency The current transformer input signal amplitude; Step S13: Use the logarithm of the frequency as the horizontal axis , the logarithm of the amplitude response is used as the ordinate , respectively construct the amplitude response characteristic curves of the standard current transformer and the current transformer to be tested; Step S14: Use -3dB curve comparison, in the amplitude-frequency characteristic curve before 500KHz, when the vertical coordinate Below -3db, horizontal axis , that is, on the horizontal axis After that, it intersects with the -3dB curve, which conforms to the steady-state broadband characteristic.

[0045] Example 8: This example is a further improvement on Example 6, and its details are as follows: Step S02 specifically includes the following steps: Step S21: The broadband test device and the GPS module are started. The GPS module sends a trigger signal to the signal generation module according to the set time. After receiving the trigger signal, the signal generation module and the balun MMIC power amplifier send a transient wave signal simulating a short-circuit fault to the primary side of the current transformer under test and the standard current transformer. Step S22: After the current transformer under test and the standard current transformer receive the transient wave signal simulating a short-circuit fault on the primary side, the secondary sides of the current transformer under test and the standard current transformer will sense corresponding electrical signals; the data acquisition module of the broadband test device synchronously collects the output signals of the secondary sides of the two current transformers and records the voltage or current value at each moment; Step S23: The collected transient wave data of the current transformer to be tested and the standard current transformer are transmitted to the data analysis unit. The data analysis unit uses a similarity analysis algorithm to perform similarity calculation, and judges whether the current transformer to be tested is qualified based on the calculated similarity result, and generates a similarity report.

[0046] Based on the calculated similarity results, a similarity report is generated. The similarity report records the similarity value of each test and the corresponding transient wave parameters in detail, so as to evaluate the accuracy and consistency of the transient wave collected by the tested current transformer.

[0047] Example 9: This example is a further improvement on Example 8, and its details are as follows: The similarity analysis algorithm in step S23 includes: The algorithm based on cross-correlation function is used to calculate the discrete time series of transient wave data collected by the current transformer to be tested and the standard current transformer. and , Represents the current transformer under test The transient amplitude value collected at each moment, where is a discrete time index, is the amplitude of the transient wave collected by the standard current transformer at the same sampling time, and the cross-correlation function Defined as: ; in is the length of the data sequence, is the time delay; if the waveform similarity ≥97%, it means that the current transformer to be tested is qualified.

[0048] By calculating the waveform similarity between the standard current transformer and the current transformer to be tested, The closer the value is to 1, the higher the similarity between the two transient waves.

[0049] Example 10: This example is a further improvement on Example 6, and its details are as follows: Step S03 specifically includes: Step S31: Adjust the parameters of the signal generating module. The GPS device triggers the signal generating module according to the set time and sends a transient wave signal containing obvious traveling wave head characteristics to the primary side of the current transformer to be tested. The traveling wave head usually has the characteristics of a fast rising edge and can simulate the traveling wave signal generated at the moment of fault occurrence in the power system.

[0050] Step S32: The secondary side of the current transformer to be tested senses an electrical signal containing traveling wave header information, and the data acquisition module of the broadband test device acquires the electrical signal containing traveling wave header information at a high sampling frequency; Step S33: During the acquisition process, the wave head is located by wavelet transform, and the starting time of the traveling wave head is recorded; based on the collected traveling wave head data, the traveling wave location algorithm is used for analysis; Common traveling wave location algorithms calculate the fault distance based on the propagation speed of traveling waves in the transmission line and the arrival time difference of the traveling wave head. , the double-ended traveling wave positioning formula is expressed as: , the wave speed of the transmission line , full length of line , record the time difference between the current transformers at both ends collecting the traveling wave head, and thus calculate the fault distance.

[0051] Step S34: Repeat the above steps multiple times to evaluate the accuracy and reliability of the traveling wave positioning function of the current transformer under test based on the traveling wave head, count the deviations between the wave head interval time of the current transformer under test and the wave head interval time of the standard current transformer, and calculate indicators including the average deviation and standard deviation; see Table 1 below for an example of the wave head interval test data: Table 1 Wave head interval test data .

[0052] Step S35: If the difference between the mean deviation and the standard deviation is less than 0.05 μs, and the maximum deviation between the wave crest interval of the current transformer under test and the wave crest interval of the standard current transformer is less than 0.1 μs, the current transformer under test passes the test. A traveling wave location function test report is generated, providing a reference for the application of current transformers in traveling wave fault location in actual power systems.

[0053] Through the above steps, the broadband test device can be used to comprehensively perform transient signal testing on the current transformer, and complete the test evaluation of transient wave similarity and traveling wave positioning function.

[0054] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A balun MMIC power amplifier, characterized in that: It includes a 1:1 balun differential circuit, an MMIC power amplifier and a 1:K balun differential circuit, wherein the 1:1 balun differential circuit and the 1:K balun differential circuit are respectively connected to the differential input end and the differential output end of the MMIC power amplifier; The 1:1 balun differential circuit, which is used to input the weak high-frequency current signal generated by the signal generating module of the broadband test device, is converted into a balanced differential signal, and the input and output signal amplitude ratio is 1:1; The MMIC power amplifier is used to perform high-gain amplification on the differential signal obtained after processing by the 1:1 balun differential circuit; The 1: K balun differential circuit is used to optimize the balance-unbalance characteristics of the signal after high-gain amplification by the MMIC power amplifier, and adjust the signal amplitude through its special ratio structure.

2. A balun MMIC power amplifier according to claim 1, characterized in that: The 1:1 balun differential circuit includes an inductor L1, a capacitor C1, a capacitor C2 and a resistor R1; The first end of the inductor L1 is connected to the RF input end, the second end of the inductor L1 is connected to the first end of the capacitor C1, the first end of the resistor R1, and the first end of the capacitor C2, the second end of the capacitor C1 is connected to the differential output end, the second end of the resistor R1 is grounded, and the second end of the capacitor C2 is grounded.

3. The balun MMIC power amplifier according to claim 2, wherein: The 1:K balun differential circuit includes an inductor L2, a capacitor C3, a capacitor C4 and a resistor R3; The first end of the inductor L2 is connected to the differential input end, the second end of the inductor L2 is connected to the first end of the capacitor C3, the first end of the resistor R3 and the first end of the capacitor C4, the second end of the capacitor C4 is connected to the single-ended output end, the second end of the resistor R3 is grounded, and the second end of the capacitor C4 is grounded.

4. The balun MMIC power amplifier according to claim 3, characterized in that: It also includes a resistor R2, the differential output end of the 1:1 balun differential circuit is connected to the first end of the resistor R2 and the differential input end of the MMIC power amplifier, the differential output end of the MMIC power amplifier is connected to the differential input end of the 1:K balun differential circuit, and the second end of the resistor R2 is grounded.

5. A broadband test device based on a balun MMIC power amplifier, characterized in that: It comprises the balun MMIC power amplifier as described in any one of claims 1 to 4; the broadband testing device is used to perform broadband testing on the current transformer of the traveling wave fault ranging device.

6. A broadband testing method based on a broadband testing device, characterized in that: The broadband test device according to claim 5 is used to perform broadband testing on the current transformer of the traveling wave fault location device. The testing method comprises the following steps: Step S01: Performing a steady-state wave test on a current transformer to be tested by using a broadband test device, constructing an amplitude response characteristic curve to determine whether the current transformer to be tested meets the steady-state broadband characteristic. If so, proceeding to the next test step; Step S02: performing a transient wave test on the current transformer to be tested by the broadband test device, analyzing the waveform similarity between the transient wave of the current transformer to be tested and the transient wave of the standard current transformer, and judging whether the current transformer to be tested is qualified based on the waveform similarity result; Step S03: Based on the traveling wave head, the traveling wave positioning function test of the current transformer is performed to test the accuracy of the traveling wave fault positioning function of the current transformer to be tested, and a traveling wave positioning function test report is generated.

7. The broadband testing method based on the broadband testing device according to claim 6, characterized in that: The step S01 specifically includes the following steps: Step S11: On the control interface of the broadband test device, parameter settings are performed on the signal generation module. The parameter settings include: Set the steady-state signal to be output as a sine wave signal; The frequency range of the steady-state signal is set to: start from a low frequency of 5 Hz and gradually increase to a high frequency of 1 MHz; Set the frequency sweep step size: 1Hz in the low frequency band and 100Hz in the high frequency band; Step S12: Calculate the amplitude-frequency response of the standard current transformer and the current transformer to be tested using a formula. The amplitude-frequency response calculation formula is: ； Where, For the frequency The amplitude-frequency response gain at ; For the frequency The output signal amplitude of the lower current transformer; For the frequency The amplitude of the current transformer input signal; Step S13: Use the logarithm of the frequency as the horizontal axis , the logarithm of the amplitude response is used as the ordinate , respectively construct the amplitude response characteristic curves of the standard current transformer and the current transformer to be tested; Step S14: Use -3dB curve comparison, in the amplitude-frequency characteristic curve before 500KHz, when the vertical coordinate If it is lower than -3dB, it meets the steady-state broadband characteristics.

8. The broadband testing method based on the broadband testing device according to claim 6, characterized in that: The step S02 specifically includes the following steps: Step S21: starting the broadband test device and the GPS module. The GPS module sends a trigger signal to the signal generating module according to a set time. After receiving the trigger signal, the signal generating module and the balun MMIC power amplifier send a transient wave signal simulating a short circuit fault to the primary side of the current transformer under test and the standard current transformer. Step S22: After the current transformer under test and the standard current transformer receive the transient wave signal of the simulated short-circuit fault on the primary side, the secondary sides of the current transformer under test and the standard current transformer will induce corresponding electrical signals; the data acquisition module of the broadband test device synchronously collects the output signals of the secondary sides of the two current transformers and records the voltage value or current value at each moment; Step S23: The collected transient wave data of the current transformer to be tested and the standard current transformer are transmitted to a data analysis unit. The data analysis unit uses a similarity analysis algorithm to perform similarity calculation, and judges whether the current transformer to be tested is qualified according to the calculated similarity result, and generates a similarity report.

9. The broadband testing method based on the broadband testing device according to claim 8, characterized in that: The similarity analysis algorithm in step S23 includes: The algorithm based on cross-correlation function is used to calculate the discrete time series of transient wave data collected by the current transformer to be tested and the standard current transformer. and , and its cross-correlation function Defined as: ； in, is the length of the data sequence, is the time delay; if the waveform similarity ≥97%, it means that the current transformer to be tested is qualified.

10. The broadband testing method based on a broadband testing device according to claim 6, characterized in that: The step S03 specifically includes: Step S31: adjusting the parameters of the signal generating module, the GPS module triggers the signal generating module according to the set time, and sends a transient wave signal containing obvious traveling wave head characteristics to the primary side of the current transformer to be tested; Step S32: The secondary side of the current transformer to be tested senses an electrical signal containing traveling wave header information, and the data acquisition module of the broadband test device acquires the electrical signal containing traveling wave header information at a high sampling frequency; Step S33: During the acquisition process, the wave head is located by wavelet transform, and the starting time of the traveling wave head is recorded; based on the collected traveling wave head data, the traveling wave location algorithm is used for analysis; Step S34: repeating the above steps multiple times, counting the deviations between the wave front interval time of the current transformer to be tested and the wave front interval time of the standard current transformer multiple times, and calculating indicators including the average deviation and the standard deviation; Step S35: If the difference between the average deviation and the standard deviation is less than 0.05us, and the maximum deviation between the wave front interval time of the current transformer to be tested and the wave front interval time of the standard current transformer is less than 0.1us, then the current transformer to be tested is qualified; and a traveling wave positioning function test report is generated.

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