CN210294455U - Band-pass filter and detector for ultrahigh frequency detection of high-voltage power equipment - Google Patents
Band-pass filter and detector for ultrahigh frequency detection of high-voltage power equipment Download PDFInfo
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- CN210294455U CN210294455U CN201921127871.4U CN201921127871U CN210294455U CN 210294455 U CN210294455 U CN 210294455U CN 201921127871 U CN201921127871 U CN 201921127871U CN 210294455 U CN210294455 U CN 210294455U
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Abstract
The utility model discloses a band pass filter and detector for high voltage electric power equipment hyperfrequency detects. The band-pass filter adopts a five-order LC band-pass filter, and the five-order LC band-pass filter is connected in sequence from the first order to the fifth order; the inductor comprises an inductor L1, a capacitor C1, an inductor L2, a capacitor C2, an inductor L3, a capacitor C3, an inductor L4, a capacitor C4, an inductor L5 and a capacitor C5; one end of an inductor L1 is connected with a signal input end, the other end of the inductor L1 is connected with a capacitor C1, a capacitor C1 is connected with a common end of a capacitor C2 and an inductor L2, the other ends of a capacitor C2 and an inductor L2 are grounded, one end of an inductor L3 is connected with a non-grounded end of an inductor L2, the other end of the inductor L3 is connected with a capacitor C3, a capacitor C3 is connected with a common end of a capacitor C4 and an inductor L4, the other ends of a capacitor C4 and an inductor L4 are grounded, one end of an inductor L5 is connected with a non-grounded end of an inductor L4, the other.
Description
Technical Field
The utility model relates to an electronic instrument technical field, concretely relates to band pass filter and detector for high voltage electric power equipment hyperfrequency detects.
Background
High-voltage electrical equipment, such as gas-insulated fully-enclosed combined electrical (GIS), transformers, switch cabinets, high-voltage cables and other equipment, can excite electromagnetic wave signals of UHF (ultra high frequency) bands of hundreds of megahertz (Ghz) or even gigahertz (Ghz) when an insulation system generates partial discharge, and is particularly effective for detecting the insulation operation conditions of the GIS, the transformers and other equipment after field handover test and commissioning, and a new technology is greatly popularized in an electric power system.
UHF detection of high-voltage equipment partial discharge generally selects a frequency band of 300Mhz to 1500Mhz, and because the electromagnetic environment of a transformer substation is complex, and electromagnetic wave signals generated by corona, equipment operation and the like are generally lower than 300Mhz, the lower frequency limit of 300Mhz is selected, so that interference can be effectively avoided. The instrument equipment on the market at present usually selects a high-pass filter with a cutoff frequency of 300Mhz and a low-pass filter with a cutoff frequency of 1500Mhz to form a band-pass filter, and the current impedance matching is not good, so that the signal attenuation in a pass band is often greatly influenced.
SUMMERY OF THE UTILITY MODEL
The utility model discloses the technical problem that will solve is: instrument equipment on the market at present selects cutoff frequency 300 Mhz's high pass filter and cutoff frequency 1500 Mhz's low pass filter to constitute band pass filter usually, and does not well to impedance matching between the two at present, often influences the problem that also is very big to the signal attenuation in the passband, the utility model provides a solve a band pass filter and the detector that are used for high voltage power equipment hyperfrequency to detect of above-mentioned problem, design a section and be used for 300Mhz ~ 1500Mhz frequency channel to detect band pass filter, be used for the local of hyperfrequency signal to put the measuring usefulness specially.
The utility model discloses a following technical scheme realizes:
a band-pass filter for ultrahigh frequency detection of high-voltage power equipment comprises a band-pass filter, a band-pass filter and a band-pass filter controller, wherein the band-pass filter adopts a five-order LC band-pass filter, and the five-order LC band-pass filter is sequentially connected from a first-order LC band-pass filter to a fifth-order LC band-pass filter; the first-order LC band-pass filter comprises an inductor L1 and a capacitor C1 which are connected in series, the second-order LC band-pass filter comprises an inductor L2 and a capacitor C2 which are connected in parallel, the third-order LC band-pass filter comprises an inductor L3 and a capacitor C3 which are connected in series, the fourth-order LC band-pass filter comprises an inductor L4 and a capacitor C4 which are connected in parallel, and the fifth-order LC band-pass filter comprises an inductor L5 and a capacitor C5 which are connected in series;
one end of an inductor L1 is connected with a signal input end, the other end of the inductor L1 is connected with a capacitor C1, a capacitor C1 is connected with a common end of the capacitor C2 and the inductor L2, the other ends of the capacitor C2 and the inductor L2 are grounded, one end of the inductor L3 is connected with a non-grounded end of the inductor L2, the other end of the inductor L3 is connected with a capacitor C3, a capacitor C3 is connected with a common end of the capacitor C4 and the inductor L4, the other ends of the capacitor C4 and the inductor L4 are grounded, one end of the inductor L5 is connected with a non-grounded end of the inductor L4, the other end of.
In the preferable scheme, the first-order LC band-pass filter and the fifth-order LC band-pass filter have the same structure, and the second-order LC band-pass filter and the fourth-order LC band-pass filter have the same structure.
Preferably, the inductance of the inductor L1 and the inductance of the inductor L5 are both 14.17nH, and the capacitance of the capacitor C1 and the capacitance of the capacitor C5 are both 3.99 pF; the inductance of the inductor L2 and the inductance of the inductor L4 are both 19.51nH, and the capacitance of the capacitor C2 and the capacitance of the capacitor C4 are both 2.9 pF; the inductance of the inductor L3 is 19.92nH, and the capacity of the capacitor C3 is 2.8 pF.
Preferably, the characteristic impedance of the network formed by the fifth-order LC band-pass filters is 50 Ω.
A detector for ultrahigh frequency detection of high-voltage power equipment comprises a UHF sensor, a band-pass filter for ultrahigh frequency detection of the high-voltage power equipment, an active amplifier, an ADC (analog-to-digital converter) and a back-end system which are sequentially connected;
the UHF sensor is used for measuring an ultrahigh frequency current signal and transmitting the ultrahigh frequency current signal to the band-pass filter for ultrahigh frequency detection of the high-voltage power equipment;
the band-pass filter for ultrahigh frequency detection of the high-voltage power equipment is used for filtering interference signals lower than 300Mhz and higher than 1500Mhz of the ultrahigh frequency current signal and transmitting the signals after the interference signals are filtered to the active amplifier;
an active amplifier for amplifying the signal transmitted from the band pass filter;
the ADC is used for carrying out analog-to-digital conversion processing on the signal transmitted from the active amplifier and transmitting the processed signal to the back-end system;
and the back-end system is used for receiving the digital signal converted by the ADC and performing subsequent display for use.
Further, the amplification factor of the active amplifier is 40 DB.
The utility model discloses have following advantage and beneficial effect:
1. the utility model discloses a band pass filter for high voltage electricity equipment hyperfrequency detects designs a section and is used for the band pass filter that 300Mhz ~ 1500Mhz frequency channel detected, and is rational in infrastructure, is used for the office of hyperfrequency signal to put the detection usefulness specially, and the amplitude-frequency characteristic fluctuation is little in the passband, satisfies the demand that frequency span is big, and uses five rank LC band pass filters to constitute the characteristic impedance of network and be 50 omega, and characteristic impedance matching degree is good, and is little to the signal attenuation influence in the passageway; the problem that instrument equipment in the current market usually selects a high-pass filter with the cutoff frequency of 300Mhz and a low-pass filter with the cutoff frequency of 1500Mhz to form a band-pass filter, and when impedance matching is not good, the influence on signal attenuation in a pass band is often large is solved;
2. the utility model discloses a detector for high voltage electricity equipment hyperfrequency detects measures the hyperfrequency current signal through the UHF sensor, and give foretell band pass filter for high voltage electricity equipment hyperfrequency detection with measuring hyperfrequency current signal, this band pass filter carries out filtering processing to the signal that the UHF sensor gathered, with being less than 300Mhz in the signal and the part filtering that is higher than 1500Mhz, again through active amplifier carry out the multiple amplification of 40DB to the signal after the filtering, and pass to ADC ADC and carry out analog-to-digital conversion to the signal, finally send the signal after handling to back-end system and carry out follow-up show, in order to supply to use;
3. the utility model discloses a detector for high voltage electric power equipment hyperfrequency detects simple structure, operation convenient to use are fit for using widely by a large scale in corresponding hyperfrequency detection area.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
fig. 1 is the utility model discloses a band-pass filter circuit diagram for high voltage electric power equipment hyperfrequency detects.
Fig. 2 is the utility model discloses a band-pass filter circuit test chart for high voltage electric power equipment hyperfrequency detects.
Fig. 3 is the utility model discloses a detector structure chart for high voltage electric power equipment hyperfrequency detects.
Fig. 4 is the utility model discloses a band-pass filter circuit test data curve chart for high voltage electric power equipment hyperfrequency detects.
Detailed Description
To make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the following examples and drawings, and the exemplary embodiments and descriptions thereof of the present invention are only used for explaining the present invention, and are not intended as limitations of the present invention.
Example 1
As shown in fig. 1, 2 and 4, a band pass filter for ultrahigh frequency detection of high voltage power equipment includes that the band pass filter adopts a five-order LC band pass filter, and the five-order LC band pass filter is connected in sequence from a first-order LC band pass filter to a fifth-order LC band pass filter; the first-order LC band-pass filter comprises an inductor L1 and a capacitor C1 which are connected in series, the second-order LC band-pass filter comprises an inductor L2 and a capacitor C2 which are connected in parallel, the third-order LC band-pass filter comprises an inductor L3 and a capacitor C3 which are connected in series, the fourth-order LC band-pass filter comprises an inductor L4 and a capacitor C4 which are connected in parallel, and the fifth-order LC band-pass filter comprises an inductor L5 and a capacitor C5 which are connected in series;
one end of an inductor L1 is connected with a signal input end, the other end of the inductor L1 is connected with a capacitor C1, a capacitor C1 is connected with a common end of a capacitor C2 and an inductor L2, the other ends of a capacitor C2 and an inductor L2 are grounded, one end of an inductor L3 is connected with a non-grounded end of an inductor L2, the other end of the inductor L3 is connected with a capacitor C3, a capacitor C3 is connected with a common end of a capacitor C4 and an inductor L4, the other ends of a capacitor C4 and an inductor L4 are grounded, one end of an inductor L5 is connected with a non-grounded end of an inductor L4, the other.
Wherein: the first-order LC band-pass filter and the fifth-order LC band-pass filter have the same structure, and the second-order LC band-pass filter and the fourth-order LC band-pass filter have the same structure; the inductance of the inductor L1 and the inductance of the inductor L5 are both 14.17nH, and the capacitance of the capacitor C1 and the capacitance of the capacitor C5 are both 3.99 pF; the inductance of the inductor L2 and the inductance of the inductor L4 are both 19.51nH, and the capacitance of the capacitor C2 and the capacitance of the capacitor C4 are both 2.9 pF; the inductance of the inductor L3 is 19.92nH, and the capacity of the capacitor C3 is 2.8 pF.
The characteristic impedance of a network formed by the five-order LC band-pass filter is 50 omega.
The above design is mainly based on the following considerations, and the LC passive band-pass filter is a frequency selection device mainly composed of inductance-capacitance devices, and the main design types are as follows:
(1) butterworth filters, which are of the type characterized by a flat amplitude-frequency characteristic of the signal in the pass band, without fluctuations, have the disadvantage of an insufficient steepness in the transition band, which requires an increase in the order if the desired steepness is to be achieved.
(2) Chebyshev filters of the type which are characterized by steeper steepnesses than the Butterworth filter in the transition region, but by a slight fluctuation in the amplitude-frequency characteristic in the pass band.
(3) The steepness of the elliptic filter in the transition frequency band is larger, and the steepest of the three filters is the steepest, but as a cost, the amplitude-frequency characteristics of the elliptic filter in the band-pass and band-stop are fluctuated.
As the cutoff frequency points of the band-pass filter-3 db to be designed by the utility model are respectively 300Mhz at the lower limit and 1500Mhz at the upper limit, the frequency span is large, the requirement is high, and if the Butterworth filter is used, the order is too many, the signal attenuation in the passband can be increased; the design of the elliptical filter is too complex, so that the elliptical filter is not suitable for manufacturing discrete devices, and the comprehensive consideration is realized by using the Chebyshev filter idea.
Therefore, specific design criteria are as follows: the-3 db turning point frequency of the LC Chebyshev band-pass filter is respectively 300Mhz and 1500Mhz, the attenuation quantity at 200Mhz and 1800Mhz is not less than 20db, the amplitude-frequency fluctuation in the pass band is not more than 1db, and the characteristic impedance of the filter is 50 ohms.
First, the order of the filter is determined: n is not less than { lg (10)0.1a2-1)/2lg(fc/f2)}，
Where n is the designed filter order and must be an integer. a2 is the amount of bandstop attenuation, here 20, in db at the bandstop start frequency f 2; fc is the bandpass cutoff frequency with 3db of attenuation, 300Mhz/1500Mhz in this design; f2 is the band stop initial frequency, the design is 200Mhz/1800Mhz, the orders of the upper and lower limit frequencies are respectively calculated, and the large number is taken as the final order. Through calculation, in the design, n is 5, that is, the 5 th-order LC band-pass filter adopts a first-order parallel structure, and the structure diagram is shown in fig. 1.
Then, it is calculated by the normalized inductance-capacitance relationship, that L1 is 14.17nH (actually 14nH at the time of test), C1 is 3.99pF (actually 4pF at the time of test), L2 is 19.51nH (actually 19nH at the time of test), C2 is 2.9pF, L3 is 19.92nH (actually 20nH at the time of test), C3 is 2.8pF, L4 is 19.51nH (actually 19nH at the time of test), C4 is 2.9pF, L5 is 14.17nH (actually 14nH at the time of test), C5 is 3.99pF (actually 4pF at the time of test), and the characteristic impedance of the band-pass filter circuit network is 50 ohm.
The utility model discloses a band pass filter for high voltage electricity equipment hyperfrequency detects has designed a section and is used for the band pass filter that 300Mhz ~ 1500Mhz frequency channel detected, and is rational in infrastructure, and the office that is used for the hyperfrequency signal specially puts the detection usefulness, and the amplitude-frequency characteristic fluctuation is little in the passband, satisfies the big demand of frequency span, and uses five rank LC band pass filters to constitute the characteristic impedance of network and be 50 omega, and characteristic impedance matching degree is good, and is little to the signal attenuation influence in the passageway; the problem that instrument equipment in the current market usually selects a high-pass filter with the cutoff frequency of 300Mhz and a low-pass filter with the cutoff frequency of 1500Mhz to form a band-pass filter, and when impedance matching is not good, the influence on signal attenuation in a pass band is often large is solved.
As shown in fig. 2, fig. 2 is a circuit test diagram of a band-pass filter for ultrahigh frequency detection of high voltage power equipment, a signal generator generates a signal with an amplitude of 10dbm, a frequency of 200 and 1500Mhz, and a sine wave signal which is progressive at 20Mhz passes through the band-pass filter for ultrahigh frequency detection of high voltage power equipment and is finally connected to an oscilloscope.
As shown in fig. 4, fig. 4 is a graph of test data of a band-pass filter circuit for ultrahigh frequency detection of a high voltage power device.
The final test data is shown in table 1 below:
TABLE 1 test data sheet
From the above tests, it can be seen from the test data in Table 1 that the-3 db turning point is located approximately around 300Mhz at the lower frequency limit; the attenuation at 200Mhz is far greater than 20db, and the lower limit of frequency reaches the requirement of design index; in the pass band, the whole signal after passing through the pass band filter is weaker than the original signal, which is caused by the characteristic of a passive filter; in the pass band, the fluctuation of the signal is mainly caused by a signal source, so that the design index that the fluctuation of the amplitude-frequency signal in the pass band is not more than 1db is met; at the upper frequency limit, the signal attenuation of the signal source is large, so the turning frequency is not obvious, and due to the limitation of the testing instrument (the upper frequency limit of the signal generator is 1500Mhz), the design target can be basically achieved, and the amplitude-frequency characteristic at 1800Mhz cannot be tested, so that a more professional mechanism is required to carry out further testing.
Example 2
As shown in fig. 3, the present embodiment is different from embodiment 1 in that a detector for ultra-high frequency detection of a high-voltage power device includes a UHF sensor, the band-pass filter for ultra-high frequency detection of a high-voltage power device, an active amplifier, an ADC analog-to-digital converter, and a back-end system, which are connected in sequence;
the UHF sensor is used for measuring an ultrahigh frequency current signal and transmitting the ultrahigh frequency current signal to the band-pass filter for ultrahigh frequency detection of the high-voltage power equipment;
the band-pass filter for ultrahigh frequency detection of the high-voltage power equipment is used for filtering interference signals lower than 300Mhz and higher than 1500Mhz of the ultrahigh frequency current signal and transmitting the signals after the interference signals are filtered to the active amplifier;
the active amplifier is used for amplifying the signal transmitted from the band-pass filter, wherein the amplification factor of the active amplifier is 40 DB;
the ADC is used for carrying out analog-to-digital conversion processing on the signal transmitted from the active amplifier and transmitting the processed signal to the back-end system;
and the back-end system is used for receiving the digital signal converted by the ADC and performing subsequent display for use.
The working principle is as follows: the utility model discloses a detector for high voltage electricity equipment hyperfrequency detects measures hyperfrequency current signal through the UHF sensor, and give foretell a band pass filter for high voltage electricity equipment hyperfrequency detection with measuring hyperfrequency current signal, this band pass filter carries out filtering processing to the signal that the UHF sensor gathered, be less than 300Mhz in with the signal and be higher than 1500 Mhz's partial filtering, again through active amplifier carry out the multiple amplification of 40DB to the signal after the filtering, and pass to ADC ADC and carry out analog-to-digital conversion to the signal, finally give the rear-end system to carry out follow-up show to the signal transfer after handling, in order to supply to use.
The detector has simple structure and convenient operation and use, and is suitable for large-area popularization and use in the corresponding ultrahigh frequency detection field.
The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above description is only the embodiments of the present invention, and is not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (6)
1. A band-pass filter for ultrahigh frequency detection of high-voltage electric equipment is characterized in that: the band-pass filter adopts a five-order LC band-pass filter, and the five-order LC band-pass filter is connected in sequence from the first order to the fifth order LC band-pass filter; the first-order LC band-pass filter comprises an inductor L1 and a capacitor C1 which are connected in series, the second-order LC band-pass filter comprises an inductor L2 and a capacitor C2 which are connected in parallel, the third-order LC band-pass filter comprises an inductor L3 and a capacitor C3 which are connected in series, the fourth-order LC band-pass filter comprises an inductor L4 and a capacitor C4 which are connected in parallel, and the fifth-order LC band-pass filter comprises an inductor L5 and a capacitor C5 which are connected in series;
one end of an inductor L1 is connected with a signal input end, the other end of the inductor L1 is connected with a capacitor C1, a capacitor C1 is connected with a common end of the capacitor C2 and the inductor L2, the other ends of the capacitor C2 and the inductor L2 are grounded, one end of the inductor L3 is connected with a non-grounded end of the inductor L2, the other end of the inductor L3 is connected with a capacitor C3, a capacitor C3 is connected with a common end of the capacitor C4 and the inductor L4, the other ends of the capacitor C4 and the inductor L4 are grounded, one end of the inductor L5 is connected with a non-grounded end of the inductor L4, the other end of.
2. The band-pass filter for ultrahigh frequency detection of high voltage electric power equipment according to claim 1, characterized in that: the first-order LC band-pass filter and the fifth-order LC band-pass filter have the same structure, and the second-order LC band-pass filter and the fourth-order LC band-pass filter have the same structure.
3. The band-pass filter for ultrahigh frequency detection of high voltage electric power equipment according to claim 2, characterized in that: the inductance of the inductor L1 and the inductance of the inductor L5 are both 14.17nH, and the capacitance of the capacitor C1 and the capacitance of the capacitor C5 are both 3.99 pF; the inductance of the inductor L2 and the inductance of the inductor L4 are both 19.51nH, and the capacitance of the capacitor C2 and the capacitance of the capacitor C4 are both 2.9 pF; the inductance of the inductor L3 is 19.92nH, and the capacity of the capacitor C3 is 2.8 pF.
4. The band-pass filter for ultrahigh frequency detection of high voltage electric power equipment according to any one of claims 1 to 3, characterized in that: the characteristic impedance of a network formed by the five-order LC band-pass filter is 50 omega.
5. The utility model provides a detector that is used for high voltage electricity equipment hyperfrequency to detect which characterized in that: the UHF sensor, the band-pass filter of any one of claims 1 to 4, the active amplifier, the ADC and a back-end system which are connected in sequence;
a UHF sensor for measuring an ultra high frequency current signal and transmitting said ultra high frequency current signal to the band pass filter of any one of claims 1 to 4;
the band-pass filter of any one of claims 1 to 4, for filtering the ultrahigh frequency current signal to interference signals below 300Mhz and above 1500Mhz, and transmitting the signal after filtering the interference signals to the active amplifier;
an active amplifier for amplifying the signal transmitted from the band pass filter;
the ADC is used for carrying out analog-to-digital conversion processing on the signal transmitted from the active amplifier and transmitting the processed signal to the back-end system;
and the back-end system is used for receiving the digital signal converted by the ADC and performing subsequent display for use.
6. The apparatus according to claim 5, wherein the apparatus comprises: the amplification factor of the active amplifier is 40 DB.
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