CN112748315B - Dynamic measurement and analysis device and method for insulation performance of electrical safety tester - Google Patents
Dynamic measurement and analysis device and method for insulation performance of electrical safety tester Download PDFInfo
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Abstract
The invention discloses a dynamic insulation performance measuring and analyzing device and method for an electrical safety tester lk Discharge current sampling resistor R arc Leakage current conditioning unit, high-frequency discharge current conditioning unit, high-voltage detection conditioning unit and synchronous analog-to-digital converter U 1 Synchronous analog-to-digital converter U 2 High speed analog to digital converter U 3 The system comprises a Field Programmable Gate Array (FPGA) and a microprocessor, wherein the FPGA calculates instantaneous discharge energy, energy spectrums and sub-spectrums corresponding to different discharge pulse widths in real time, and the microprocessor runs a dynamic analysis algorithm to identify the insulation degradation degree in real time and predict the insulation degradation trend. According to the invention, through the discharge energy and frequency peak value dynamic change information, the insulation degradation trend can be effectively predicted; and the insulation characteristic is analyzed by integrating the leakage current and the discharge information, and the change rule of the physical characteristic in the insulation degradation process of the insulator is met.
Description
Technical Field
The invention relates to a dynamic measurement and analysis device and method for insulation performance in a voltage withstanding test process, and belongs to the measurement technology of a voltage withstanding tester.
Background
The deterioration process of the insulating property of the insulating material can be characterized by five stages of good insulation, internal discharge, corona, arc discharge flicker and insulation breakdown on the physical characteristics, the effective value of leakage current is used for judging the insulating property in a traditional voltage-resistant tester, and because the relative variation of the leakage current is not obvious in the deterioration process from the internal discharge to the arc discharge flicker, the leakage current only changes suddenly when the insulation breakdown is approached. Therefore, the method for measuring the quality of the insulating property of the insulating material by simply using the leakage current has low sensitivity, and can judge whether an insulation fault exists, but the potential insulation hazard is difficult to find in advance, so that whether the insulator has a weak insulation defect cannot be identified.
Unlike leakage current, the energy and frequency of the discharge signal vary significantly in different stages from the start of the internal discharge. Generally, the following steps are carried out: when the insulation is good, no discharge phenomenon exists; in the internal discharge stage, the discharge frequency is high, and the discharge energy is small; in the corona discharge stage, the discharge energy is concentrated in the intermediate frequency; when the arc is drawn and flickers, the discharge energy is concentrated in the middle and low frequency; and in the collapse stage, the discharge energy has step change. Therefore, the leakage current and the discharge signal are comprehensively utilized to identify the insulation performance of the insulation material, and the weak insulation defect can be accurately identified.
In recent years, a novel program-controlled voltage resistance measuring instrument assists in judging whether insulation defects exist by measuring a discharge current peak value. The method is characterized in that high-frequency current flowing through a tested object is rectified and then compared with an arc current threshold, if the high-frequency current is larger than the arc current threshold, an arc exists, whether the arc current with a set threshold is generated or not can be judged, but the accurate intensity, the variation trend, when the voltage of the arc generates the arc and the like cannot be known, and the method has great limitation.
Disclosure of Invention
The purpose of the invention is as follows: in order to overcome the defects of the insulation defect identification performance of the existing voltage-withstanding tester, the invention provides a dynamic measurement and analysis device and method for the insulation performance of an electrical safety tester.
The technical scheme is as follows: in order to realize the purpose, the invention adopts the technical scheme that:
an insulation performance dynamic measurement and analysis device for an electrical safety tester comprises a program-controlled alternating-current signal source, a step-up transformer, a high-voltage alternating/direct-current signal output module, a high-voltage output end interface, a return end interface and a leakage current sampling resistor R lk Discharge current sampling resistor R arc Leakage current conditioning unit, high-frequency discharge power supplyStream conditioning unit, high-voltage detection conditioning unit and synchronous analog-digital converter U 1 Synchronous analog-to-digital converter U 2 High speed analog to digital converter U 3 The FPGA and the microprocessor;
the output signal of the program control alternating current signal source is boosted by the booster transformer and then provided to the high-voltage alternating current/direct current signal output module, the output end I of the high-voltage alternating current/direct current signal output module is connected with the high-voltage output end interface, and the output end II of the high-voltage alternating current/direct current signal output module is connected with the high-voltage output end interface through the discharge current sampling resistor R arc And a leakage current sampling resistor R lk Then is connected with the interface of the reflux end;
the high-voltage output end interface and the return end interface are simultaneously connected with two input ends of the high-voltage detection conditioning unit respectively, and the output end of the high-voltage detection conditioning unit is connected with the synchronous analog-to-digital converter U 2 The input ends of the two-way valve are connected; leakage current sampling resistor R lk Is respectively connected with two input ends of the leakage current conditioning unit, and the output end of the leakage current conditioning unit is connected with the synchronous analog-to-digital converter U 1 The input ends of the two-way valve are connected; discharge current sampling resistor R arc The two ends of the high-frequency discharge current conditioning unit are respectively connected with the two input ends of the high-frequency discharge current conditioning unit, and the output end of the high-frequency discharge current conditioning unit is connected with the high-speed analog-to-digital converter U 3 Connecting;
the synchronous analog-to-digital converter U 1 Synchronous analog-to-digital converter U 2 And a high speed analog to digital converter U 3 Synchronous sampling trigger signal f connected with field programmable gate array FPGA 1 Simultaneously supplied to synchronous A/D converters U 1 And a synchronous analog-to-digital converter U 2 The acquisition control end of the FPGA generates a fixed high-frequency sampling trigger signal f 3 Supplied to a high-speed analog-to-digital converter U 3 The acquisition control terminal of (1);
and the microprocessor is interconnected with the program control alternating current signal source and the field programmable gate array FPGA.
Preferably, the leakage current conditioning unit conditions the collected signal and sends the conditioned signal to the synchronous analog-to-digital converter U 1 Synchronous analog-to-digital converter U 1 According to a synchronous sampling trigger signal f 1 Collecting leakage current waveform I lk (sampling resistance R by measuring leakage Current lk The voltage at the two ends is calculated to obtain a leakage current signal); the high-voltage detection conditioning unit conditions the acquired signal and sends the conditioned signal to the synchronous analog-to-digital converter U 2 Synchronous analog-to-digital converter U 2 According to a synchronous sampling trigger signal f 1 Collecting high-voltage partial pressure waveform U hv (a voltage waveform loaded between the high-voltage output end and the return end, namely, a voltage loaded at two ends of a tested object); the high-frequency discharge current conditioning unit conditions the acquired signal and sends the conditioned signal to the high-speed analog-to-digital converter U 3 High speed analog to digital converter U 3 Sampling trigger signal f according to fixed high frequency 3 Collecting high-frequency discharge current signal I arc (by measuring discharge current sampling resistor R arc The voltage at two ends is calculated to obtain a high-frequency discharge current signal I arc The high-frequency discharge current signal I arc I.e. the current signal in series at the return terminal; leakage current is a low frequency characteristic and high frequency discharge current is a high frequency characteristic, and thus the leakage current and the high frequency discharge current are sampled using different sampling channels).
Preferably, the field programmable gate array FPGA is internally provided with a synchronous sampling controller, a discharge signal sampling controller and a high-speed discharge signal preprocessor; the synchronous sampling controller calculates and outputs a synchronous sampling trigger signal f according to the output signal frequency of the program control alternating current signal source 1 Synchronous sampling trigger signal f 1 Is recorded as t 0 The sampling period is marked as T; discharge signal sampling controller with t 0 Generating a fixed high-frequency sampling trigger signal f by taking the moment as a trigger moment 3 (ii) a The high-speed discharge signal preprocessor calculates the total instantaneous discharge amount in the current sampling period T according to an instantaneous discharge amount algorithm.
Preferably, the analog-to-digital converter U is synchronized 1 Collected leakage current waveform I lk Synchronous analog-to-digital converter U stored in first-out memory FIFO # 1 2 Collected high-voltage partial pressure waveform U hv High speed analog to digital converter U stored in FIFO # 2 3 Collected high-frequency discharge current signal I arc Stored in a first-in first-out memory FIFO # 3; the memory FIFO # 1 and the memory FIFO # 2 have the storage depth N, the memory FIFO # 3 has the storage depth kN, and k is f 3 /f 1 The integer part of the quotient; the instantaneous discharge total amount calculated by the high-speed discharge signal preprocessor is stored in a first-in first-out memory FIFO # 4, and the sampling time of the storage addresses corresponding to the memory FIFO # 4 and the memory FIFO # 1 is the same.
Preferably, the total amount of instantaneous discharge is according to the formula
And obtaining, namely: for the high-frequency discharge current signal I in the time period between (n-1) T time and nT time arc (t) performing integral operation to obtain the total discharge quantity Q (nT) in the time period, and taking the Q (nT) as the instantaneous total discharge quantity at the nT moment; n is the number of current sampling points, and T is the sampling period (i.e., sampling interval).
Preferably, the field programmable gate array FPGA internally disposes a spectrum register set; the high-speed discharge signal preprocessor obtains the slave t according to the discharge spectrum statistical calculation method 0 The total discharge amount and the total discharge times corresponding to different discharge current pulse widths from the moment t to the current moment t, and the result is stored in a discharge spectrum register group.
Preferably, the discharge spectrum statistical algorithm comprises a pulse width measurement algorithm, a discharge energy spectrum algorithm and a discharge frequency spectrum algorithm;
at high frequency discharge current signal I arc (t) starting a pulse width measurement algorithm at the moment of polarity reversal, namely starting current discharge current pulse width measurement at the moment of polarity reversal starting, and ending current discharge current pulse width measurement at the moment of polarity reversal stopping: if the measured pulse width length of the discharge current is within the range of a preset upper limit threshold and a preset lower limit threshold (the upper limit threshold corresponds to the longest discharge current pulse width, and the lower limit threshold corresponds to the shortest discharge current pulse width and is used for distinguishing high-frequency noise), recording the discharge current pulse width as the current pulse width m, and starting the next group of discharge current pulse width measurement; otherwise, the current pulse signal is considered as disturbance and is ignored;
discharge energy spectrum algorithm record t 0 Time t and 1 during the time period between the times, the total charge amount of the discharge current having the pulse width m (the total charge amount corresponding to the high-frequency discharge current having the pulse width m and applied to the object to be measured) is expressed as Power _ Spectrum (m, t) 0 ,t 1 )；
Discharge frequency spectrum algorithm record t 0 Time t and 1 the number of occurrences of a discharge current having a pulse width of m (the number of occurrences of a high-frequency discharge current having a pulse width of m and a high-voltage signal applied to a test object) in a time period between times is expressed as stostic _ Spectrum (m, t) 0 ,t 1 )；
Mixing Power _ Spectrum (m, t) 0 ,t 1 ) And Stotistic _ Spectrum (m, t) 0 ,t 1 ) Stored in the discharge spectrum register set.
Preferably, the microprocessor reads data in the memory FIFO # 1, the memory FIFO # 2, the memory FIFO # 3, the memory FIFO # 4 and the discharge spectrum register group in real time, obtains a high voltage signal frequency spectrum (a high voltage signal frequency spectrum at a high voltage output end, and a high voltage signal at the high voltage output end is distorted by some tested products) and a leakage current signal frequency spectrum (a current flowing through the tested products and flowing from a return end) by using a discrete fourier algorithm, and calculates main parameters including an effective value, a peak value, a distortion degree and a frequency spectrum of the high voltage/leakage current, and auxiliary parameters including a discharge intensity spectrum, a discharge frequency spectrum, a discharge total amount and a total number of occurrences of discharge.
Preferably, the microprocessor adopts an anti-saturation cascade PID cascade control algorithm to feed back and regulate the output signal of the program control alternating current signal source in real time according to the obtained main parameter and the obtained auxiliary parameter, so as to realize the rapid constant voltage control with the current limiting function of the source output.
An analysis method based on any one of the dynamic insulation performance measuring and analyzing devices for the electrical safety standard tester comprises the following steps:
(1) The two ends of the tested object are respectively connected with the high-voltage output end interface and the return end interface, and the program-controlled alternating-current signal source adjusts the voltage amplitude of the output signal according to the microprocessor;
a synchronous sampling controller arranged in the FPGA for calculating and outputting a synchronous sampling trigger signal f according to the output signal frequency of the programmable AC signal source 1 Synchronous sampling trigger signal f 1 Is recorded as t 0 The sampling period is marked as T; the storage depths of the memory FIFO # 1 and the memory FIFO # 2 are both N;
the leakage current conditioning unit conditions the acquired signal and sends the conditioned signal to the synchronous analog-to-digital converter U 1 Synchronous analog-to-digital converter U 1 According to a synchronous sampling trigger signal f 1 Collecting leakage current waveform I lk And stored in a first-in first-out memory FIFO # 1; the high-voltage detection conditioning unit conditions the acquired signal and sends the conditioned signal to the synchronous analog-to-digital converter U 2 Synchronous analog-to-digital converter U 2 According to a synchronous sampling trigger signal f 1 Collecting high-voltage partial pressure waveform U hv And stored in a first-in first-out memory FIFO # 2;
(2) A discharge signal sampling controller built in the FPGA for t 0 Generating a fixed high-frequency sampling trigger signal f by taking the moment as a trigger moment 3 (ii) a Memory FIFO # 3 has a memory depth kN, k f 3 /f 1 The integer part of the quotient;
the high-frequency discharge current conditioning unit conditions the acquired signal and sends the conditioned signal to the high-speed analog-to-digital converter U 3 High speed analog to digital converter U 3 Sampling trigger signal f according to fixed high frequency 3 Collecting high-frequency discharge current signal I arc And stored in a first-in first-out memory FIFO # 3;
(3) The high-speed discharge signal preprocessor arranged in the field programmable gate array FPGA calculates the total instantaneous discharge amount in the current sampling period T according to an instantaneous discharge amount algorithm, the result is stored in a first-in first-out memory FIFO # 4, and the sampling moments of the corresponding storage addresses of the memory FIFO # 4 and the memory FIFO # 1 are the same (the synchronous display of the discharge waveform is convenient);
(4) A high-speed discharge signal preprocessor built in the field programmable gate array FPGA acquires the slave t according to a discharge spectrum statistical calculation method 0 From time to current time tThe total discharge amount and the total discharge times corresponding to different discharge pulse widths, and the result is stored in a discharge spectrum register group;
(5) The microprocessor reads data in the memory FIFO # 1, the memory FIFO # 2, the memory FIFO # 3, the memory FIFO # 4 and the discharge spectrum register group in real time, obtains a high-voltage signal frequency spectrum and a leakage current signal frequency spectrum by adopting a discrete Fourier algorithm, and calculates main parameters including a high-voltage/leakage current effective value, a peak value, a distortion degree and a frequency spectrum and auxiliary parameters including a discharge intensity spectrum, a discharge frequency spectrum, a discharge total amount and total discharge occurrence times;
(6) The microprocessor feeds back and adjusts the output signal of the program control alternating current signal source in real time by adopting an anti-saturation cascade PID cascade control algorithm according to the main parameter and the auxiliary parameter, and the rapid constant voltage control with the current limiting function of source output is realized.
(7) And (3) adjusting the voltage amplitude of the program control alternating current signal source by the microprocessor, repeating the steps (1) to (6) to obtain a leakage current waveform, a discharge energy spectrum and a discharge frequency spectrum under different voltage amplitudes, and judging and predicting the insulation state degradation starting point of the tested product according to a dynamic analysis algorithm.
Preferably, the dynamic analysis algorithm is an algorithm for predicting the insulation state (including five types of good insulation, internal discharge, corona, arc discharge flicker and breakdown) of the tested object according to the variation trends of the discharge energy spectrum and the discharge frequency spectrum, the various insulation states of different tested objects are different in corresponding discharge energy spectrum and discharge frequency spectrum characteristics, and the dynamic analysis algorithm sets fixed thresholds and variation rate thresholds of different insulation states to classify the insulation states.
Preferably, the microprocessor can also obtain additional information such as a measured object impedance network, a loss angle of a capacitive load and the like according to the obtained main parameter and the auxiliary parameter.
Has the advantages that: compared with the prior art, the dynamic insulation performance measuring and analyzing device for the electrical safety standard tester provided by the invention has the following advantages: 1. the invention describes the insulation performance of the tested object based on the information of instantaneous discharge energy, discharge energy spectrum and discharge frequency spectrum, and has high sensitivity and good accuracy; 2. according to the invention, through the discharge energy and frequency peak value dynamic change information, the insulation degradation trend can be effectively predicted; 3. the invention analyzes the insulation characteristic by integrating the leakage current and the discharge information, and accords with the change rule of the physical characteristic in the insulation degradation process of the insulator.
Drawings
FIG. 1 is a schematic diagram of the apparatus of the present invention;
FIG. 2 is a schematic diagram of the internal logic structure of the FPGA in the device of the present invention;
FIG. 3 is a discharge spectrum of a high frequency transformer according to the present invention when a voltage withstand test is performed by applying a 1.3kV/1.4kV/1.5kV AC voltage between the primary and secondary sides thereof, where 3 (a) is a discharge spectrum of applying a 1.3kV AC voltage, 3 (b) is a discharge spectrum of applying a 1.4kV AC voltage, and 3 (c) is a discharge spectrum of applying a 1.5kV AC voltage;
FIG. 4 is a discharge spectrum diagram of a voltage withstand test performed by applying a 5kV AC voltage between a secondary side and an iron core of a certain type of power frequency transformer according to the present invention;
in fig. 3 and 4: the gray line segment represents the number of discharge occurrences, and Counts represents the count of the number of discharge occurrences; black line segment represents total discharge amount, nC represents unit of total discharge amount, 1nc =1 × 10 -9 C。
Detailed Description
The invention is described in detail below with reference to the figures and the embodiments.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In order to improve the sensitivity and accuracy of the insulation performance discrimination of a tested product and predict the insulation degradation trend, as shown in fig. 1, the invention provides an insulation performance dynamic measurement and analysis device for an electrical safety tester, which acquires a high-voltage signal, a leakage current signal and a high-frequency discharge current signal at a high speed, calculates the information of discharge instantaneous energy, energy spectrums, frequency spectrums and the like corresponding to different discharge signal pulse widths in real time in an FPGA (field programmable gate array), and judges the insulation defect degree and the insulation degradation trend through an insulation performance dynamic analysis algorithm in a microprocessor.
The dynamic insulation performance measuring and analyzing device for the electrical safety tester comprises a program-controlled alternating-current signal source, a step-up transformer, a high-voltage alternating/direct-current signal output module, a high-voltage output end interface, a return end interface and a leakage current sampling resistor R lk Discharge current sampling resistor R arc Leakage current conditioning unit, high-frequency discharge current conditioning unit, high-voltage detection conditioning unit and synchronous analog-digital converter U 1 Synchronous analog-to-digital converter U 2 High speed analog to digital converter U 3 The FPGA and the microprocessor; the output signal of the program control alternating current signal source is boosted by the booster transformer and then provided to the high-voltage alternating current/direct current signal output module, the output end I of the high-voltage alternating current/direct current signal output module is connected with the high-voltage output end interface, and the output end II of the high-voltage alternating current/direct current signal output module is connected with the high-voltage output end interface through the discharge current sampling resistor R arc And a leakage current sampling resistor R lk Then is connected with the interface of the reflux end; the high-voltage output end interface and the return end interface are simultaneously connected with two input ends of the high-voltage detection conditioning unit respectively, and the output end of the high-voltage detection conditioning unit is connected with the synchronous analog-to-digital converter U 2 The input ends of the two-way valve are connected; leakage current sampling resistor R lk Is respectively connected with two input ends of the leakage current conditioning unit, and the output end of the leakage current conditioning unit is connected with the synchronous analog-to-digital converter U 1 The input ends of the two-way valve are connected; discharge current sampling resistor R arc The two ends of the high-frequency discharge current regulation unit are respectively connected with the two input ends of the high-frequency discharge current regulation unit, and the output end of the high-frequency discharge current regulation unit is connected with the high-speed analog-to-digital converter U 3 Connecting; the synchronous dieDigital converter U 1 Synchronous analog-to-digital converter U 2 And a high speed analog to digital converter U 3 Synchronous sampling trigger signal f connected with field programmable gate array FPGA 1 Simultaneously supplied to synchronous analog-to-digital converters U 1 And a synchronous analog-to-digital converter U 2 The fixed high-frequency sampling trigger signal f generated by the field programmable gate array FPGA 3 Supplied to a high-speed analog-to-digital converter U 3 The acquisition control terminal of (1); and the microprocessor is interconnected with the program control alternating current signal source and the field programmable gate array FPGA.
As shown in fig. 2, the field programmable gate array FPGA is internally provided with a synchronous sampling controller, a discharge signal sampling controller and a high-speed discharge signal preprocessor; the synchronous sampling controller calculates and outputs a synchronous sampling trigger signal f according to the output signal frequency of the program control alternating current signal source 1 Synchronous sampling trigger signal f 1 Is noted as t 0 The sampling period is marked as T; discharge signal sampling controller with t 0 Generating a fixed high-frequency sampling trigger signal f by taking the moment as a trigger moment 3 (ii) a The high-speed discharge signal preprocessor calculates the total instantaneous discharge amount in the current sampling period T according to an instantaneous discharge amount algorithm. Synchronous analog-to-digital converter U 1 Collected leakage current waveform I lk Synchronous analog-to-digital converter U stored in first-out memory FIFO # 1 2 Collected high-voltage partial pressure waveform U hv High speed analog to digital converter U stored in FIFO # 2 3 Collected high-frequency discharge current signal I arc Stored in a first-in first-out memory FIFO # 3; the memory FIFO # 1 and the memory FIFO # 2 have the storage depth N, the memory FIFO # 3 has the storage depth kN, and k is f 3 /f 1 The integer part of the quotient; the instantaneous discharge total amount calculated by the high-speed discharge signal preprocessor is stored in a first-in first-out memory FIFO # 4, and the sampling time of the storage addresses corresponding to the memory FIFO # 4 and the memory FIFO # 1 is the same.
In the withstand voltage measuring process, time domain and frequency domain parameters of a high-voltage signal and a leakage current signal, information such as instantaneous discharge signal energy, a discharge energy spectrum and a discharge frequency spectrum are acquired in real time through a high-speed data acquisition technology and a signal processing algorithm, and whether a measured product has insulation defects or not can be identified, the insulation degradation trend can be predicted, and the initial discharge voltage of an arc can be captured.
The implementation method based on the device is described by taking the example of applying 1.3kV/1.4kV/1.5kV alternating voltage between the primary and the secondary of a certain high-frequency transformer to carry out withstand voltage test respectively as follows:
(1) And the microprocessor adopts STM32F767, sets the frequency of an output signal of the program control alternating current signal source to be 50Hz and the target voltage to be 1000V, and starts the program control alternating current signal source to output.
(2) The FPGA adopts an EP4C10E22 chip design, a synchronous sampling controller is arranged in the FPGA, and a synchronous sampling trigger signal f with the output frequency of 51.2kHz is output 1 Trigger 16bit, 250kSPS double-channel A/D converter U 1 And U 2 Real-time collection of leakage current waveform I lk And high voltage division waveform U hv The synchronous conversion result of the analog-to-digital converter is stored in a memory FIFO # 1 and a memory FIFO # 2; synchronous sampling trigger signal f 1 Is recorded as t 0 Time of day; the parameters of the memory FIFO # 1 and the memory FIFO # 2 are: the word length is 16 bits, and the storage depth is 1024 points.
(3) The FPGA is internally provided with a high-speed discharge signal preprocessor for outputting a fixed high-frequency sampling trigger signal f with the sampling frequency of 5MHz 3 Triggering 12bit/10MSPS high-speed analog-to-digital converter U 3 Real-time acquisition of high-frequency discharge current signal I arc And stores the conversion result in a memory FIFO # 3; the parameters of memory FIFO # 3 are: the word length is 12bit, and the storage depth is 8096 points.
(4) The memory FIFO # 1, the memory FIFO # 2, and the memory FIFO # 3 set an empty flag EmptyFlag when there is no data in the memory, and set a full flag FullFlag when the buffer is full. The memory FIFO # 1 and the memory FIFO # 2 stop storing after the memory is full, and the memory FIFO # 3 performs cyclic overlay storage by overwriting the data that entered first after the memory is full.
(5) Synchronous sampling controller is in the process of supplying to dual-channel analog-to-digital converter U 1 And U 2 SendingSynchronous sampling trigger signal f 1 Simultaneously sending synchronous sampling trigger signal f to high-speed discharge signal preprocessor 1 The high-speed discharge signal preprocessor calculates the total instantaneous discharge amount in the current sampling period T (1/51.2 kHz) according to an instantaneous discharge amount algorithm, and stores the result in a memory FIFO # 4, wherein the sampling time of the memory FIFO # 4 and the sampling time of the memory FIFO # 1 corresponding to the memory addresses are the same. The total amount of instantaneous discharge is according to the formula
And obtaining, namely: for the high-frequency discharge current signal I in the time period between (n-1) T time and nT time arc (t) performing integral operation to obtain the total discharge quantity Q (nT) in the time period, and taking the Q (nT) as the instantaneous total discharge quantity at the nT moment; and n is the number of current sampling points.
(6) The high-speed discharge signal preprocessor obtains the slave t according to the discharge spectrum statistical calculation method 0 The total discharge amount and the total discharge times corresponding to different discharge current pulse widths from the moment t to the current moment t, and the result is stored in a discharge spectrum register group; the discharge spectrum statistical algorithm comprises a pulse width measurement algorithm, a discharge energy spectrum algorithm and a discharge frequency spectrum algorithm.
And (3) a pulse width measurement algorithm: at high frequency discharge current signal I arc (t) starting a pulse width measurement algorithm at the moment of polarity reversal, namely starting current discharge current pulse width measurement at the moment of polarity reversal starting, and ending current discharge current pulse width measurement at the moment of polarity reversal stopping: if the measured pulse width length of the discharge current is within the range of the preset upper and lower limit threshold values, recording the pulse width of the discharge current as the current pulse width m, and starting the next group of pulse width measurement of the discharge current; otherwise, the current pulse signal is considered as disturbance and is ignored.
Discharge energy spectrum algorithm: discharge energy spectrum algorithm record t 0 Time and t 1 During the time period between the moments, the total charge with the discharge current pulse width m is expressed as Power _ Spectrum (m, t) 0 ,t 1 )。
Discharge frequency spectrum algorithm: discharge frequency spectrum algorithm record t 0 Time t and 1 during the time period between the time of day,the number of occurrences of a discharge current pulse width of m is denoted as Stotistic _ Spectrum (m, t) 0 ,t 1 )。
Mixing Power _ Spectrum (m, t) 0 ,t 1 ) And Stotistic _ Spectrum (m, t) 0 ,t 1 ) Stored in the discharge spectrum register set.
(7) The microprocessor adopts a non-blocking real-time operating system architecture, reads data in a memory FIFO # 1, a memory FIFO # 2, a memory FIFO # 3, a memory FIFO # 4 and a discharge spectrum register group, obtains a high-voltage signal frequency spectrum and a leakage current signal frequency spectrum by adopting a discrete Fourier algorithm, calculates main parameters including a high-voltage/leakage current effective value, a peak value, a distortion degree and the frequency spectrum, and calculates auxiliary parameters including a discharge intensity spectrum, a discharge frequency spectrum, a discharge total amount and a total discharge occurrence number.
(8) And (3) when the microprocessor reads the data of the buffer area each time, judging whether the FullFlag mark is set, if the FullFlag mark is set, indicating that the waveform is discontinuous, resetting the buffer area of each memory, and starting to acquire and process again from the step (2).
(9) The microprocessor adopts an anti-saturation cascade PID cascade control algorithm to feed back and regulate the output signal of the program control alternating current signal source in real time according to the main parameter and the auxiliary parameter, and the rapid constant voltage control with the current limiting function of the source output is realized.
(10) The microprocessor reads the data in the memory FIFO # 4, the initial data in the memory FIFO # 4 is the same as the initial data in the memory FIFO # 1 and the memory FIFO # 2 in time, and the instantaneous discharge total amount of each sampling point on the real-time leakage current waveform is obtained according to the sampling rate proportional relation.
(11) The microprocessor adjusts the target voltage of the program control alternating current signal source from 1000V to 1500V and steps to 100V; and (5) repeating the steps (2) to (10) to obtain a leakage current waveform, a discharge energy spectrum and a discharge frequency spectrum under different voltage amplitudes, and judging and predicting the insulation state degradation starting point of the tested object according to a dynamic analysis algorithm. The dynamic analysis algorithm is an algorithm for predicting the insulation state (comprising five types of good insulation, internal discharge, corona, arc discharge flicker and collapse) of a tested object according to the change trends of a discharge energy spectrum and a discharge frequency spectrum, the characteristics of the discharge energy spectrum and the discharge frequency spectrum are different corresponding to various insulation states of different tested objects, and the dynamic analysis algorithm sets fixed thresholds and change rate thresholds of different insulation states and classifies the insulation states.
(12) And the microprocessor can also obtain additional information such as a measured object impedance network, a loss angle of a capacitive load and the like according to the obtained main parameter and the auxiliary parameter.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.
In the description of the specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by using equivalent alternatives or equivalent variations fall within the scope of the present invention.
Claims (10)
1. The utility model provides an electric ann rule insulating properties dynamic measurement and analytical equipment for tester which characterized in that: involving programme controlAlternating current signal source, step-up transformer, high voltage alternating current/direct current signal output module, high voltage output terminal interface, backflow terminal interface, leakage current sampling resistor R lk Discharge current sampling resistor R arc Leakage current conditioning unit, high-frequency discharge current conditioning unit, high-voltage detection conditioning unit and synchronous analog-to-digital converter U 1 Synchronous analog-to-digital converter U 2 High speed analog to digital converter U 3 The FPGA and the microprocessor; identifying whether a tested product has insulation defects or not, predicting the insulation degradation trend and capturing the initial discharge voltage of an electric arc by acquiring time domain and frequency domain parameters of a high-voltage signal and a leakage current signal in real time and information of instantaneous discharge signal energy, discharge energy spectrum and discharge frequency spectrum;
the output signal of the program control alternating current signal source is boosted by the booster transformer and then provided to the high-voltage alternating current/direct current signal output module, the output end I of the high-voltage alternating current/direct current signal output module is connected with the high-voltage output end interface, and the output end II of the high-voltage alternating current/direct current signal output module is connected with the high-voltage output end interface through the discharge current sampling resistor R arc And a leakage current sampling resistor R lk Then is connected with the interface of the reflux end;
the high-voltage output end interface and the return end interface are simultaneously connected with two input ends of the high-voltage detection conditioning unit respectively, and the output end of the high-voltage detection conditioning unit is connected with the synchronous analog-to-digital converter U 2 The input ends of the two-way valve are connected; leakage current sampling resistor R lk Is respectively connected with two input ends of the leakage current conditioning unit, and the output end of the leakage current conditioning unit is connected with the synchronous analog-to-digital converter U 1 The input ends of the two-way valve are connected; discharge current sampling resistor R arc The two ends of the high-frequency discharge current regulation unit are respectively connected with the two input ends of the high-frequency discharge current regulation unit, and the output end of the high-frequency discharge current regulation unit is connected with the high-speed analog-to-digital converter U 3 Connecting;
the synchronous analog-to-digital converter U 1 Synchronous analog-to-digital converter U 2 And a high speed analog to digital converter U 3 A synchronous sampling trigger signal f generated by the FPGA connected with the FPGA 1 Simultaneously supplied to synchronous analog-to-digital converters U 1 And synchronizationAnalog-to-digital converter U 2 The acquisition control end of the FPGA generates a fixed high-frequency sampling trigger signal f 3 Supplied to a high-speed analog-to-digital converter U 3 The acquisition control terminal of (2);
and the microprocessor is interconnected with the program control alternating current signal source and the field programmable gate array FPGA.
2. The dynamic insulation performance measuring and analyzing device for the electrical safety tester according to claim 1, wherein: the leakage current conditioning unit conditions the acquired signal and sends the conditioned signal to the synchronous analog-to-digital converter U 1 Synchronous analog-to-digital converter U 1 According to a synchronous sampling trigger signal f 1 Collecting leakage current waveform I lk (ii) a The high-voltage detection conditioning unit conditions the acquired signal and sends the conditioned signal to the synchronous analog-to-digital converter U 2 Synchronous analog-to-digital converter U 2 According to a synchronous sampling trigger signal f 1 Collecting high-voltage partial pressure waveform U hv (ii) a The high-frequency discharge current conditioning unit conditions the acquired signal and sends the conditioned signal to the high-speed analog-to-digital converter U 3 High speed analog to digital converter U 3 Sampling trigger signal f according to fixed high frequency 3 Collecting high-frequency discharge current signal I arc 。
3. The dynamic insulation performance measuring and analyzing device for the electrical safety tester according to claim 1, wherein: the FPGA is internally provided with a synchronous sampling controller, a discharge signal sampling controller and a high-speed discharge signal preprocessor; the synchronous sampling controller calculates and outputs a synchronous sampling trigger signal f according to the output signal frequency of the program control alternating current signal source 1 Synchronous sampling trigger signal f 1 Is recorded as t 0 The sampling period is marked as T; discharge signal sampling controller with t 0 Generating a fixed high-frequency sampling trigger signal f by taking the moment as a trigger moment 3 (ii) a The high-speed discharge signal preprocessor calculates the total instantaneous discharge amount in the current sampling period T according to an instantaneous discharge amount algorithm.
4.The dynamic measurement and analysis device of the insulation performance for the electrical safety specification tester according to claim 3, characterized in that: synchronous analog-to-digital converter U 1 Collected leakage current waveform I lk Synchronous analog-to-digital converter U stored in first-out memory FIFO #1 2 Collected high-voltage partial pressure waveform U hv High speed analog to digital converter U stored in FIFO #2 3 Collected high-frequency discharge current signal I arc Stored in a first-in first-out memory FIFO # 3; the memory FIFO #1 and the memory FIFO #2 have the storage depth N, the memory FIFO #3 has the storage depth kN, and k is f 3 /f 1 The integer part of the quotient; the instantaneous discharge total amount calculated by the high-speed discharge signal preprocessor is stored in a first-in first-out memory FIFO #4, and the sampling time of the storage addresses corresponding to the memory FIFO #4 and the memory FIFO #1 is the same.
5. The dynamic measurement and analysis device of the insulation performance for the electrical safety specification tester according to claim 3, characterized in that: the total amount of instantaneous discharge is according to the formula
And (3) obtaining, namely: for the high-frequency discharge current signal I in the time period between (n-1) T time and nT time arc (t) carrying out integral operation to obtain the total discharge quantity Q (nT) in the time period, and taking the Q (nT) as the instantaneous total discharge quantity at the nT moment; and n is the number of current sampling points.
6. The dynamic measurement and analysis device of the insulation performance for the electrical safety specification tester according to claim 3, characterized in that: a field programmable gate array FPGA internally-arranged electric spectrum register set; the high-speed discharge signal preprocessor obtains the slave t according to the discharge spectrum statistical calculation method 0 The total discharge amount and the total discharge times corresponding to different discharge current pulse widths from the moment t to the current moment t, and the result is stored in a discharge spectrum register group.
7. The dynamic measurement and analysis device of the insulation performance for the electrical safety specification tester according to claim 6, characterized in that: the discharge spectrum statistical algorithm comprises a pulse width measurement algorithm, a discharge energy spectrum algorithm and a discharge frequency spectrum algorithm;
at high frequency discharge current signal I arc (t) starting a pulse width measurement algorithm at the moment of polarity reversal, namely starting current discharge current pulse width measurement at the moment of polarity reversal starting and ending current discharge current pulse width measurement at the moment of polarity reversal stopping: if the measured pulse width length of the discharge current is within the range of the preset upper and lower limit threshold values, recording the pulse width of the discharge current as the current pulse width m, and starting the next group of pulse width measurement of the discharge current; otherwise, the current pulse signal is considered as disturbance and is ignored;
discharge energy spectrum algorithm records t 0 Time t and 1 during the time interval, the total charge quantity with the discharge current pulse width m is expressed as Power _ Spectrum (m, t) 0 ,t 1 )；
Discharge frequency spectrum algorithm record t 0 Time t and 1 the number of occurrences of a discharge current pulse width m in the time period between the timings is denoted as Stotistic _ Spectrum (m, t) 0 ,t 1 )；
Power _ Spectrum (m, t) 0 ,t 1 ) And Stotistic _ Spectrum (m, t) 0 ,t 1 ) Stored in the discharge spectrum register set.
8. The dynamic measurement and analysis device of the insulation performance for the electrical safety specification tester according to claim 4, characterized in that: the microprocessor reads data in the memory FIFO #1, the memory FIFO #2, the memory FIFO #3, the memory FIFO #4 and the discharge spectrum register group in real time, obtains a high-voltage signal frequency spectrum and a leakage current signal frequency spectrum by adopting a discrete Fourier algorithm, and calculates main parameters including a high-voltage/leakage current effective value, a peak value, a distortion degree and a frequency spectrum and auxiliary parameters including a discharge intensity spectrum, a discharge frequency spectrum, a discharge total amount and a discharge total occurrence frequency.
9. The dynamic measurement and analysis device of the insulation performance for the electrical safety specification tester according to claim 8, characterized in that: and the microprocessor feeds back and adjusts the output signal of the program control alternating current signal source in real time by adopting an anti-saturation cascade PID cascade control algorithm according to the obtained main parameter and the obtained auxiliary parameter.
10. An analysis method of the dynamic insulation performance measurement and analysis device for the electrical safety tester according to any one of claims 1 to 9, the method comprising the steps of: the method comprises the following steps:
(1) The two ends of the tested object are respectively connected with the high-voltage output end interface and the return end interface, and the program-controlled alternating-current signal source adjusts the voltage amplitude of the output signal according to the microprocessor;
a synchronous sampling controller arranged in the FPGA for calculating and outputting a synchronous sampling trigger signal f according to the output signal frequency of the programmable AC signal source 1 Synchronous sampling trigger signal f 1 Is noted as t 0 The sampling period is marked as T; the storage depths of the memory FIFO #1 and the memory FIFO #2 are both N;
the leakage current conditioning unit conditions the acquired signal and sends the conditioned signal to the synchronous analog-to-digital converter U 1 Synchronous analog-to-digital converter U 1 According to a synchronous sampling trigger signal f 1 Collecting leakage current waveform I lk And stored in the first-in first-out memory FIFO # 1; the high-voltage detection conditioning unit conditions the acquired signal and sends the conditioned signal to the synchronous analog-to-digital converter U 2 Synchronous analog-to-digital converter U 2 According to a synchronous sampling trigger signal f 1 Collecting high-voltage partial pressure waveform U hv And stored in a first-in first-out memory FIFO # 2;
(2) A discharge signal sampling controller built in the FPGA with t 0 Generating a fixed high-frequency sampling trigger signal f by taking the moment as a trigger moment 3 (ii) a Memory FIFO #3 has a memory depth of kN and k of f 3 /f 1 The integer part of the quotient;
the high-frequency discharge current conditioning unit conditions the acquired signal and sends the conditioned signal to the high-speed analog-to-digital converter U 3 High speed analog to digital converter U 3 Sampling trigger signal according to fixed high frequencyf 3 Collecting high-frequency discharge current signal I arc And stored in the first-in first-out memory FIFO # 3;
(3) The high-speed discharge signal preprocessor arranged in the field programmable gate array FPGA calculates the total instantaneous discharge amount in the current sampling period T according to an instantaneous discharge amount algorithm, the result is stored in a first-in first-out memory FIFO #4, and the sampling moments of the corresponding storage addresses of the memory FIFO #4 and the memory FIFO #1 are the same;
(4) A high-speed discharge signal preprocessor built in the field programmable gate array FPGA acquires the slave t according to a discharge spectrum statistical calculation method 0 The total discharge amount and the total discharge times corresponding to different discharge pulse widths from the moment to the current t moment are stored in a discharge spectrum register group;
(5) The microprocessor reads data in the memory FIFO #1, the memory FIFO #2, the memory FIFO #3, the memory FIFO #4 and the discharge spectrum register group in real time, obtains a high-voltage signal frequency spectrum and a leakage current signal frequency spectrum by adopting a discrete Fourier algorithm, and calculates main parameters including a high-voltage/leakage current effective value, a peak value, a distortion degree and a frequency spectrum and auxiliary parameters including a discharge intensity spectrum, a discharge frequency spectrum, a discharge total amount and total discharge occurrence times;
(6) The microprocessor feeds back and adjusts the output signal of the program control alternating current signal source in real time by adopting an anti-saturation cascade PID cascade control algorithm according to the main parameter and the auxiliary parameter;
(7) And (3) adjusting the voltage amplitude of the program control alternating current signal source by the microprocessor, repeating the steps (1) to (6) to obtain a leakage current waveform, a discharge energy spectrum and a discharge frequency spectrum under different voltage amplitudes, and judging and predicting the insulation state degradation starting point of the tested product according to a dynamic analysis algorithm.
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