CN114384383A - Circuit and method for positioning ultrahigh frequency partial discharge point - Google Patents
Circuit and method for positioning ultrahigh frequency partial discharge point Download PDFInfo
- Publication number
- CN114384383A CN114384383A CN202210280331.XA CN202210280331A CN114384383A CN 114384383 A CN114384383 A CN 114384383A CN 202210280331 A CN202210280331 A CN 202210280331A CN 114384383 A CN114384383 A CN 114384383A
- Authority
- CN
- China
- Prior art keywords
- resistor
- sensing node
- partial discharge
- circuit
- signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/14—Circuits therefor, e.g. for generating test voltages, sensing circuits
Abstract
The application relates to a circuit and a method for positioning a ultrahigh frequency partial discharge point, which comprises a signal preprocessing module, a signal conditioning module and a single chip microcomputer which are sequentially connected in series, wherein the signal preprocessing module comprises a band-pass filter, a low-noise amplifier and a power detection circuit which are sequentially connected in series, and the signal conditioning module comprises a buffer, a first comparator, a first analog electronic switch, a step integral circuit and a reset circuit. According to the invention, the ultrahigh frequency partial discharge signal is converted into the periodic stepped output waveform through the signal preprocessing module and the signal conditioning module, the number of times of resetting the falling edge of the stepped output waveform of each sensing node in unit time is detected through the single chip microcomputer, the position of the partial discharge source is positioned, the high-speed A/D converter is omitted, and the measuring circuit is simplified.
Description
Technical Field
The application relates to the technical field of electronic information processing, in particular to a circuit and a method for positioning an ultrahigh frequency partial discharge point.
Background
The partial discharge positioning is the key content of the insulation state monitoring of the power equipment, and has important significance for early warning of insulation faults and finding of the position of a partial discharge source. RSS, i.e. received signal strength, is one of the main methods to achieve very high frequency partial discharge localization. According to a wireless signal space transmission Fries formula, the signal power ratio received by the sensing nodes is inversely proportional to the distance between the sensing nodes and the partial discharge source, and the position of the partial discharge source can be positioned by measuring the signal power received by the sensing nodes to obtain the ratio of the distance between the sensing nodes and the partial discharge source.
In the existing method for locating partial discharge points of electrical equipment, a method for detecting signal power received by a sensing node is shown in fig. 1, the sensing node receives an ultrahigh frequency partial discharge signal, and after filtering amplification and power detection and frequency reduction, an a/D analog-to-digital converter is used for digitalization and measuring the partial discharge signal power. The ultrahigh frequency partial discharge signal frequency is up to 3GHz, and after power detection and frequency reduction, the ultrahigh frequency partial discharge signal frequency is usually between 1MHz and 50MHz, a high-speed A/D converter is needed for digitalization, and a large amount of partial discharge data are stored, processed and transmitted, so that the system design is complicated, the realization is difficult, the cost is high, the industrialization and actual large-scale deployment are not facilitated, and the requirements of low power consumption, simple structure and low cost of the power internet of things on the sensing terminal cannot be met.
Disclosure of Invention
The invention aims to provide a circuit and a method for positioning an ultrahigh frequency partial discharge point, which convert an ultrahigh frequency partial discharge signal into a periodic stepped output waveform, realize the positioning of the position of a partial discharge source by detecting the number of times of resetting a falling edge of the stepped output waveform of each sensing node in unit time, omit a high-speed A/D converter and simplify a measuring circuit.
The invention adopts a technical scheme that: a circuit for positioning an ultrahigh frequency partial discharge point comprises a signal preprocessing module, a signal conditioning module and a single chip microcomputer which are sequentially connected in series, wherein the signal preprocessing module comprises a band-pass filter, a low-noise amplifier and a power detection circuit which are sequentially connected in series, and the signal conditioning module comprises a buffer, a first comparator, a first analog electronic switch, a step integral circuit and a reset circuit; the output end of the signal preprocessing module is connected with the positive input end of the buffer, the negative input end of the buffer is connected with the output end, one end of the first analog electronic switch is connected with the output end of the buffer, and the other end of the first analog electronic switch is connected with the step integrating circuit; the positive input end of the first comparator is connected with the output end of the buffer, the negative input end of the first comparator is connected with the reference level, and the output end of the first comparator is connected with the first analog electronic switch; the step integration circuit is electrically connected with the reset circuit and the single chip microcomputer, after the step integration circuit converts the partial discharge pulse signal output by the power detection circuit into a step output waveform, the reset circuit resets the step output waveform to a low level and is connected with the input end of the single chip microcomputer.
Further, the ladder integration circuit comprises an operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor and a first capacitor; after the first resistor and the second resistor are connected in series, one end of the first resistor is connected with the first analog electronic switch, and the other end of the first resistor is connected with the output end of the operational amplifier; after the third resistor and the fourth resistor are connected in series, one end of the third resistor is connected with the output end of the operational amplifier, and the other end of the third resistor is grounded; the positive input end of the operational amplifier is connected with the series point of the first resistor and the second resistor, the negative input end of the operational amplifier is connected with the series point of the third resistor and the fourth resistor, and the output end of the operational amplifier is connected with the singlechip; one end of the first capacitor is connected with the series point of the first resistor and the second resistor, and the other end of the first capacitor is grounded.
Further, the reset circuit comprises a power supply, a second comparator, a fifth resistor, a sixth resistor, a seventh resistor, a second analog electronic switch and a third analog electronic switch; the second analog electronic switch is connected with the first capacitor in parallel; after the fifth resistor and the sixth resistor are connected in series, one end of the fifth resistor is connected with a power supply, and the other end of the fifth resistor is grounded; the seventh resistor is connected in series with the third analog electronic switch and then connected in parallel with the sixth resistor; the positive input end of the second comparator is connected with the output end of the operational amplifier, the negative input end of the second comparator is connected with the series point of the fifth resistor and the sixth resistor, and the output end of the second comparator is connected with the second analog electronic switch and the third analog electronic switch.
Further, the reference level is a threshold value for eliminating the partial discharge signal.
Further, the first comparator and the second comparator are high-speed comparators with TTL outputs or COMS outputs.
The invention adopts another technical scheme that: a method for positioning a ultrahigh frequency partial discharge point comprises the following specific steps:
s1: at least four sensing nodes are distributed on a local discharge source, one sensing node is set as a reference sensing node, the distance between the reference sensing node and the local discharge source is selected by an operator, other sensing nodes are randomly distributed, and each sensing node is provided with a circuit according to the technical scheme;
s2: converting the ultrahigh frequency partial discharge signal received by the sensing node into a partial pulse signal through a signal preprocessing module of the circuit in the step S1, performing integral charging on the signal conditioning module according to the partial pulse signal, discharging after the partial pulse signal reaches a preset high potential value, resetting the output to a low level, repeating the charging and discharging process, converting the partial pulse signal into a periodic stepped output waveform, wherein the step number of the stepped output waveform in one period and the partial discharge pulse number required for reaching the preset high potential valuemEqual;
s3: detecting the unit time of each sensing node through a single chip microcomputerTNumber of falling edge reset by inner step type output waveformN i WhereiniA serial number of the sensing node is represented,i=1,2,3……x，xthe number of the sensing nodes is;
s4: calculating the distance from each sensing node except the reference sensing node to the local discharge source, wherein the specific calculation formula is as follows:
wherein the content of the first and second substances,jto refer to the node number of the sensing node,j∈x，r i is as followsiThe distance from each sensing node to the partial discharge source,r j to reference the sense node to partial discharge source distance,N j sensing node for reference in unit timeTThe inner stepped output waveform resets the number of falling edges,na path loss factor for a radio propagation space;
s5: and calculating the position of the partial discharge source according to a trilateration positioning algorithm.
Further, the path loss factor of the radio propagation space in the step S4nThe calculation method comprises the following steps:
setting a simulated partial discharge signal source as a calibration signal source near a reference sensing node, adjusting the distance between the reference sensing node and the calibration signal source, and measuring the distance of the reference sensing node before and after the distance adjustment in unit timeTResetting the number of falling edges by the inner step type output waveform, and calculating and solving the path loss factor of the radio propagation spacenThe calculation formula is as follows:
wherein the content of the first and second substances,r j1 to adjust the distance between the reference sensing node before calibration and the calibration signal source,r j2 in order to adjust the distance between the reference sensing node and the calibration signal source,N j1 for adjusting the reference sensing node in unit timeTThe inner stepped output waveform resets the number of falling edges,N j2 for adjusting the reference sensing node in unit timeTThe inner stepped output waveform resets the number of falling edges.
Further, when the number of the set sensing nodes is 4, substituting the other three sensing nodes except the reference sensing node into the trilateration positioning algorithm in the step S5 to position the position of the partial discharge source;
and when the number of the set sensing nodes is more than 4, combining the other sensing nodes except the reference sensing node, wherein the three sensing nodes are one combination, substituting each combination into the trilateration positioning algorithm in the step S5 to obtain a positioning point, and calculating and positioning the position of the partial discharge source by using the positioning point obtained by each combination through the centroid.
Further, the unit timeTIs 3000 power frequency periods.
The invention has the beneficial technical effects that:
(1) according to the invention, RSS positioning is realized by detecting the number of times of the falling edge of the stepped output waveform reset of each sensing node in unit time, so that the measuring result is more stable and reliable, the difficulty is low, and the method is easy to realize;
(2) the invention replaces the mode of detecting the signal power received by the sensing node in the prior art by detecting the frequency of the stepped output waveform reset falling edge of each sensing node in unit time, thereby omitting a high-speed A/D converter on hardware equipment, needing no large-capacity data storage and processing, greatly reducing the power consumption, having simple and compact circuit structure, reducing the complexity and the system cost of a data processing unit of the sensing terminal, and being suitable for the actual field deployment of the partial discharge sensing terminal;
(3) according to the invention, a large amount of data transmission is not needed, and wireless transmission is an important component of the power consumption of the sensing unit of the power internet of things, so that the wireless communication burden is effectively reduced, and the power consumption is reduced.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of a prior art circuit for detecting signal power received at a sensing node;
FIG. 2 is a schematic layout of a sensor node according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of an embodiment of the present invention;
FIG. 4 is a schematic diagram of the operation of the step integrator circuit and the reset circuit according to the embodiment of the present invention;
FIG. 5 is a schematic diagram of a stepped output waveform output by a signal conditioning module according to an embodiment of the present invention;
FIG. 6 is a schematic circuit diagram of a signal conditioning module according to an embodiment of the present invention;
fig. 7 is a schematic diagram of trilateration location in accordance with an embodiment of the present invention.
The reference signs explain: 1-single chip microcomputer, 2-buffer, 3-first comparator, 4-operational amplifier, 5-second comparator, R1-first resistor, R2-second resistor, R3-third resistor, R4-fourth resistor, R5-fifth resistor, R6-sixth resistor, R7-seventh resistor, C1-first capacitor, Vr1-reference level, Vc-supply source, S1-first analog electronic switch, S2-second analog electronic switch, S3-third analog electronic switch.
Detailed Description
In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and thus the present invention is not limited to the specific embodiments disclosed below.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs. The use of "first," "second," and similar terms in this patent application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships are changed accordingly.
As shown in fig. 2-6, a circuit for locating a superfrequency partial discharge point comprises a signal preprocessing module, a signal conditioning module and a single chip microcomputer 1 which are sequentially connected in series, wherein the signal preprocessing module is connected with a preset sensing node, and the signal preprocessing module comprises a band-pass filter, a low-noise amplifier and a power detection circuit which are sequentially connected in series. Due to the complex electromagnetic field environment of the working area of the transformer substation, low-frequency interference and wireless communication interference generated by a large number of power equipment exist, wherein the wireless interference mainly comprises frequency-modulated radio waves and mobile communication interference. Therefore, after the ultrahigh frequency partial discharge signal of the partial discharge source is detected, a band-pass filter is needed to be adopted to inhibit the interference of other signals on the partial discharge detection, and the 3dB bandwidth of the band-pass filter is 200 MHz-800 MHz. In order to improve the detection sensitivity of the embodiment of the invention, the ultrahigh frequency partial discharge signal needs to be amplified by a low noise amplifier. The power detection circuit is used for detecting the power of the partial discharge pulse signal and outputting a pulse signal which is lower in bit high-frequency partial discharge signal and more gentle in frequency.
The signal conditioning module comprises a buffer 2, a first comparator 3, a first analog electronic switch S1, a ladder integration circuit and a reset circuit; the output end of the signal preprocessing module is connected with the positive input end of the buffer 2, the negative input end of the buffer 2 is connected with the output end, one end of the first analog electronic switch S1 is connected with the output end of the buffer 2, and the other end is connected with the step integrator circuit; the positive input end of the first comparator 3 is connected with the output end of the buffer 2, and the negative input end is connected with the reference level Vr1Connected with an output terminal connected with a first analog electronic switch S1, the reference level Vr1The magnitude of (1) is a threshold value for eliminating a partial discharge signal; the step integration circuit, the reset circuit and the single chip microcomputer 1 are electrically connected, after the step integration circuit converts the partial discharge pulse signal output by the power detection circuit into a step output waveform, when the step output waveform reaches a high potential preset value, the reset circuit resets the step output waveform to a low level and is connected with the input end of the single chip microcomputer 1, and the signal input into the single chip microcomputer 1 is a periodic step signal.
In the embodiment of the present invention, the ladder integration circuit includes an operational amplifier 4, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first capacitor C1; after the first resistor R1 and the second resistor R2 are connected in series, one end of the first resistor R1 is connected with the first analog electronic switch S1, and the other end of the first resistor R2 is connected with the output end of the operational amplifier 4; after the third resistor R3 and the fourth resistor R4 are connected in series, one end of the third resistor R3 is connected with the output end P3 of the operational amplifier 4, and the other end of the third resistor R4 is grounded; the positive input end of the operational amplifier 4 is connected with a series point P1 of a first resistor R1 and a second resistor R2, the negative input end of the operational amplifier 4 is connected with a series point P2 of a third resistor R3 and a fourth resistor R4, and the output end P3 of the operational amplifier 4 is connected with the singlechip 1; one end of the first capacitor C1 is connected with the series point P1 of the first resistor R1 and the second resistor R2, and the other end is grounded.
The reset circuit comprises a power supply Vc, a second comparator 5, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a second analog electronic switch S2 and a third analog electronic switch S3; the second analog electronic switch S2 is connected in parallel with the first capacitor C1; after the fifth resistor R5 and the sixth resistor R6 are connected in series, one end of the fifth resistor R5 is connected with a power supply Vc, and the other end of the fifth resistor R6 is grounded; the seventh resistor R7 is connected in series with the third analog electronic switch S3 and then connected in parallel with the sixth resistor R6; the positive input end of the second comparator 5 is connected to the output end P3 of the operational amplifier 4, the negative input end is connected to the series point P4 of the fifth resistor R5 and the sixth resistor R6, and the output end is connected to the second analog electronic switch S2 and the third analog electronic switch S3.
The first comparator 3 and the second comparator 5 are high-speed comparators with TTL output or COMS output; the resistances of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4 and the sixth resistor R6 are all 10K omega, the resistance of the fifth resistor R5 is 1K omega, the resistance of the seventh resistor R7 is 100 omega, and the power supply Vc is 3.3V.
The working process of the signal conditioning module of the embodiment of the invention is as follows:
(1) a partial discharge pulse signal output by the power detector enters a signal conditioning module, is isolated and buffered by a buffer 2, enters a stepped integrating circuit at one path, and enters a first comparator 3 at the other path;
(2) the amplitude of the partial discharge pulse signal output by the buffer 2 is larger than the reference level Vr1The first comparator 3 outputs a high level, otherwise outputs a low level;
(3) when the first comparator 3 outputs a high level, the first analog electronic switch S1 is closed, and the partial discharge pulse signal charges the first capacitor C1 through the first resistor R1;
(4) when the level value of the output terminal P3 of the operational amplifier 4 reaches the preset level value, the second comparator 5 outputs a high level; the preset level value is the level value at the serial connection point P4 of the fifth resistor R5 and the sixth resistor R6 and is recorded as Vr2(ii) a The preset level value Vr may be changed by adjusting the resistance values of the fifth resistor R5 and the sixth resistor R62But must ensure a predetermined level value Vr2For high level of digital circuit, Vr is set in the embodiment of the invention2=3V；
(5) The second comparator 5 outputs high level, so that the second analog electronic switch S2 is closed, the first capacitor C1 is discharged, the level value at the serial point P1 of the first resistor R1 and the second resistor R2 is reduced to 0, and the level value at the output terminal P3 of the operational amplifier 4 is reduced;
(6) when the level of the output terminal P3 of the operational amplifier 4 falls below Vr2 If = 0.3V, the second comparator 5 outputs a low level, the second analog electronic switch S2 and the third analog electronic switch S3 are turned off, and the series connection point P of the fifth resistor R5 and the sixth resistor R6 is set at the high level4Potential Vr of2Returning to 3V, the partial discharge pulse recharges the first capacitor C1;
(7) repeating the processes (2) to (6), and carrying out a new round of charging, resetting and discharging on the first capacitor C1 to form a periodic stepped output waveform;
(8) the periodic stepped output waveform generated in the process (7) is used for triggering the single chip microcomputer 1, the level reset falling edge of the periodic stepped output waveform triggers the external interruption of the single chip microcomputer 1, and the single chip microcomputer 1 calculates unit timeTThe number of interruptions in the memory.
According to the working process, the embodiment of the invention adopts a method for positioning the ultrahigh frequency partial discharge point, and the method comprises the following specific steps:
s1: at least four sensing nodes are distributed on the partial discharge source, one sensing node is set as a reference sensing node, and the circuit is arranged at each sensing node. As shown in fig. 2, the present inventionIn the embodiment, four sensing nodes are arranged, and the distances between the four sensing nodes and a local discharge source are r respectively1、r2、r3And r4And one sensing node is a reference sensing node. When the reference sensing nodes are set, the distances between the reference sensing nodes and the local discharge source are selected by an operator to serve as calibration values for subsequently solving the distances between other sensing nodes and the local discharge source, and other sensing nodes are randomly arranged around the local discharge source.
S2: converting the ultrahigh frequency partial discharge signal received by the sensing node into a partial pulse signal through a signal preprocessing module of the circuit in the step S1, performing integral charging on the signal conditioning module according to the partial pulse signal, discharging after the partial pulse signal reaches a preset high potential value, resetting the output to a low level, repeating the charging and discharging process, converting the partial pulse signal into a periodic stepped output waveform, wherein the step number of the stepped output waveform in one period and the partial discharge pulse number required for reaching the preset high potential valuemAre equal.
According to the wireless signal space transmission Fries formula, the ratio of the signal power received by the sensing nodes is inversely proportional to their distance from the local discharge source, namely:
wherein the content of the first and second substances,i，keach of which represents a serial number of the sensing node,i=1,2,3……x，k=1,2,3……x，xthe number of the sensing nodes is the number,P i is as followsiThe power of the signal received by each sensing node,P k is as followskThe power of the signal received by each sensing node,r i is as followsiThe distance of each sensing node from the source of the partial discharge,r k is as followskThe distance of each sensing node from the source of the partial discharge,nis the path loss factor of the radio propagation space.
Let us rememberiPower detection of individual sensing nodeThe output voltage of the wave circuit isV i The method comprises the following steps:
wherein the content of the first and second substances,a=a 1 a 2the value of the voltage is, in terms of circuit constant,a 1for the front-end amplification and the insertion loss of the band-pass filter,a 2the power detection conversion coefficient.
Combining formulas (1) and (2) results in:
wherein the content of the first and second substances,V k is as followskThe output voltage of the power detection circuit of each sensing node.
As shown in FIG. 4, for a single sensing node, the step integration circuit performs integration charging once every time a partial discharge pulse is generated, and the charging time ist m And forming a step voltage until the step voltage reaches a predetermined level value Vr 2Then, the reset circuit performs discharge reset. This process is repeated to ultimately form a periodic stepped output waveform as shown in fig. 5. In FIG. 6, during charging at P3Output voltage of point
Comprises the following steps:
wherein R1 is the resistance of the first resistor R1, C1Is the capacitance value of the first capacitor C1,V iN is the potential value of the series point of the first analog electronic switch S1 and the first resistor R1. The partial discharge pulse signal passes through the first resistor R1. The output voltage at the point P3 is powerThe accumulation of the output voltage of the detection circuit is substituted into the formula (2), and the partial discharge pulse power accumulation received by the sensing node can be obtained. Assuming a single sensing node requirementmPartial discharge pulse for making stepped voltage value reach preset level value Vr2The closer the sensing node is to the partial discharge source, the stronger the power of the received partial discharge signal, the shorter the time from the integral charging to the reset discharging,mthe smaller the value; on the contrary, the farther the sensing node is away from the partial discharge source, the weaker the power of the received partial discharge signal is, the longer the time from the integral charging to the reset discharging is,mthe larger the value.
S3: the single chip microcomputer 1 is used for detecting the unit time of each sensing nodeTNumber of falling edge reset by inner step type output waveformN i WhereiniIndicating the sensing node serial number.
In a unit timeTIn the meantime, the shorter the time from the integral charging to the reset discharging of the sensing node, the more the number of times of the reset falling edge,N i the greater the value of (A); on the contrary, in unit timeTIn the meantime, the longer the time from the integral charging to the reset discharging of the sensing node, the fewer the number of reset falling edges,N i the smaller the value of (c). The time from the integral charging to the reset discharging of the sensing node is inversely proportional to the power of a partial discharging signal received by the sensing node, so the times of the reset falling edge of the sensing nodeN i Proportional to the power of the partial discharge signal received at the sensing node. Since the partial discharge signal has a certain randomness, the unit time is statisticallyTThe step integration circuit and the reset circuit of the sensing node in the time period need to be capable of completing charging and discharging reset for at least 100 times so as to ensure sufficient measurement data stability and positioning accuracy. In the embodiment of the invention, the unit timeTIs 3000 power frequency periods, namely 1 minute.
S4: the method comprises the following steps of calculating the distance from each sensing node except the reference sensing node to a local discharge source, and comprises the following specific steps:
number of falling edges due to reset of sensing nodeN i Is connected with the sensing nodeThe power of the received partial discharge signal is proportional, so equation (5) can be obtained:
wherein the content of the first and second substances,jto refer to the node number of the sensing node,j∈x，r i is as followsiThe distance from each sensing node to the partial discharge source,r j to reference the sense node to partial discharge source distance,na path loss factor for a radio propagation space;n not less than 2, when propagating in a straight line in free space, isn =2, the more complex the communication environment,nthe larger the value. Equation (5) can be further written as:
wherein the distance between the reference sensing node and the partial discharge sourcer j Has been determined at the time of setting the reference sensing node, the firstiEach sensing node is in unit timeTNumber of falling edge reset by inner step type output waveformN i And the reference sensing node is in unit timeTNumber of falling edge reset by inner step type output waveformN j Have been measured in step S3, the distance from each sensing node to the local discharge source can be obtained by determining the value of the path loss factor of the radio propagation spacenThe calculation method comprises the following steps:
setting a simulated partial discharge signal source as a calibration signal source near a reference sensing node, adjusting the distance between the reference sensing node and the calibration signal source, and measuring the distance of the reference sensing node before and after the distance adjustment in unit timeTResetting the number of falling edges by the inner step type output waveform, and calculating and solving the path loss factor of the radio propagation spacenThe calculation formula is as follows:
wherein the content of the first and second substances,r j1 to adjust the distance between the reference sensing node before calibration and the calibration signal source,r j2 in order to adjust the distance between the reference sensing node and the calibration signal source,N j1 for adjusting the reference sensing node in unit timeTThe inner stepped output waveform resets the number of falling edges,N j2 for adjusting the reference sensing node in unit timeTThe inner stepped output waveform resets the number of falling edges.
S5: calculating the position of the partial discharge source according to a trilateration positioning algorithm;
RSS location can be implemented by a number of algorithms, and in embodiments of the present invention, trilateration location algorithms are used to implement RSS location. Taking 4 sensing nodes as an example, the sensing node 4 in fig. 2 is taken as a reference sensing node and used for calibrating the measurement distance, and the other 3 sensing nodes realize positioning calculation. The specific method comprises the following steps:
as shown in FIG. 7, the distances from the local discharge source to the 3 sensing nodes are respectivelyr 1、r 2、r 3. And respectively drawing 3 circles by taking the sensing node as the center of a circle and the distance between the sensing node and the partial discharge source as the radius, wherein the intersection of the three circles is the position of the partial discharge source. For convenience of calculation, a rectangular coordinate system is established by taking the position of the sensing node Q1 as the origin of coordinates and taking the connecting line of the sensing node Q1 and the sensing node Q2 as the abscissa axis. Let the position coordinate of the sensing node Q2 be (d0); the position coordinate of the sensing node Q3 is (a, b) The location of the source of partial discharge is indicated byx, y) The trilateration based positioning algorithm is:
from equation (8) we can obtain:
the result obtained by the formula (9) is the position coordinate of the partial discharge source.
When more than 4 sensing nodes are adopted, the other sensing nodes except the reference sensing node are combined, the three sensing nodes are one combination, each combination is substituted into the trilateration positioning algorithm in the step S5 to obtain a positioning point, and the positioning point obtained by each combination is used for calculating and positioning the position of the partial discharge source through the centroid. Theoretically, the more the number of sensing nodes, the higher the positioning accuracy, but the higher the cost, so that in actual use, the appropriate number of sensing nodes can be selected according to the actual application scenario.
The embodiment of the invention replaces the mode of detecting the signal power received by the sensing node in the prior art by detecting the frequency of the stepped output waveform reset falling edge of each sensing node in unit time, thereby omitting a high-speed A/D converter on hardware equipment, needing no large-capacity data storage and processing, greatly reducing the power consumption, having simple and compact circuit structure, reducing the complexity of a data processing unit of the sensing terminal and the system cost, and being suitable for the actual field deployment of the partial discharge sensing terminal. RSS positioning is realized by detecting the number of times of the falling edge of the stepped output waveform reset of each sensing node in unit time, and the measuring result is more stable and reliable, has low difficulty and is easy to realize; a large amount of data transmission is not needed, and wireless transmitting transmission is an important component of power consumption of the sensing unit of the power internet of things, so that wireless communication burden is effectively reduced, and power consumption is reduced.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. A circuit for positioning an ultrahigh frequency partial discharge point is characterized by comprising a signal preprocessing module, a signal conditioning module and a single chip microcomputer which are sequentially connected in series, wherein the signal preprocessing module comprises a band-pass filter, a low-noise amplifier and a power detection circuit which are sequentially connected in series, and the signal conditioning module comprises a buffer, a first comparator, a first analog electronic switch, a step integral circuit and a reset circuit; the output end of the signal preprocessing module is connected with the positive input end of the buffer, the negative input end of the buffer is connected with the output end, one end of the first analog electronic switch is connected with the output end of the buffer, and the other end of the first analog electronic switch is connected with the step integrating circuit; the positive input end of the first comparator is connected with the output end of the buffer, the negative input end of the first comparator is connected with the reference level, and the output end of the first comparator is connected with the first analog electronic switch; the step integration circuit is electrically connected with the reset circuit and the single chip microcomputer, after the step integration circuit converts the partial discharge pulse signal output by the power detection circuit into a step output waveform, the reset circuit resets the step output waveform to a low level and is connected with the input end of the single chip microcomputer.
2. The circuit for locating a uhf partial discharge point according to claim 1, wherein the ladder integration circuit includes an operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, and a first capacitor; after the first resistor and the second resistor are connected in series, one end of the first resistor is connected with the first analog electronic switch, and the other end of the first resistor is connected with the output end of the operational amplifier; after the third resistor and the fourth resistor are connected in series, one end of the third resistor is connected with the output end of the operational amplifier, and the other end of the third resistor is grounded; the positive input end of the operational amplifier is connected with the series point of the first resistor and the second resistor, the negative input end of the operational amplifier is connected with the series point of the third resistor and the fourth resistor, and the output end of the operational amplifier is connected with the singlechip; one end of the first capacitor is connected with the series point of the first resistor and the second resistor, and the other end of the first capacitor is grounded.
3. The circuit for locating a uhf partial discharge point according to claim 2, wherein the reset circuit includes a power supply, a second comparator, a fifth resistor, a sixth resistor, a seventh resistor, a second analog electronic switch and a third analog electronic switch; the second analog electronic switch is connected with the first capacitor in parallel; after the fifth resistor and the sixth resistor are connected in series, one end of the fifth resistor is connected with a power supply, and the other end of the fifth resistor is grounded; the seventh resistor is connected in series with the third analog electronic switch and then connected in parallel with the sixth resistor; the positive input end of the second comparator is connected with the output end of the operational amplifier, the negative input end of the second comparator is connected with the series point of the fifth resistor and the sixth resistor, and the output end of the second comparator is connected with the second analog electronic switch and the third analog electronic switch.
4. The circuit according to claim 1, wherein the reference level is a threshold for eliminating partial discharge signals.
5. A circuit for locating uhf partial discharge points as set forth in claim 3, wherein the first and second comparators are high speed comparators of TTL output or COMS output.
6. A method for positioning a ultrahigh frequency partial discharge point is characterized by comprising the following specific steps:
s1: laying at least four sensing nodes for a local discharge source, setting one of the sensing nodes as a reference sensing node, selecting the distance between the reference sensing node and the local discharge source by an operator, randomly laying other sensing nodes, and arranging the circuit as claimed in any one of claims 1 to 5 at each sensing node;
s2: converting the ultrahigh frequency partial discharge signal received by the sensing node into a partial pulse signal through a signal preprocessing module of the circuit in the step S1, performing integral charging on a signal conditioning module according to the partial pulse signal, discharging after reaching a preset high potential value, resetting the output to a low level, repeating the charging and discharging process, converting the partial pulse signal into a periodic stepped output waveform, and outputting the stepped output waveformThe number of steps of the output waveform in one period and the number of partial discharge pulses required for reaching a preset high potential valuemEqual;
s3: detecting the unit time of each sensing node through a single chip microcomputerTNumber of falling edge reset by inner step type output waveformN i WhereiniA serial number of the sensing node is represented,i=1,2,3……x，xthe number of the sensing nodes is;
s4: calculating the distance from each sensing node except the reference sensing node to the local discharge source, wherein the specific calculation formula is as follows:
wherein the content of the first and second substances,jto refer to the node number of the sensing node,j∈x，r i is as followsiThe distance from each sensing node to the partial discharge source,r j to reference the sense node to partial discharge source distance,N j sensing node for reference in unit timeTThe inner stepped output waveform resets the number of falling edges,na path loss factor for a radio propagation space;
s5: and calculating the position of the partial discharge source according to a trilateration positioning algorithm.
7. The method according to claim 6, wherein the path loss factor of radio propagation space in step S4nThe calculation method comprises the following steps:
setting a simulated partial discharge signal source as a calibration signal source near a reference sensing node, adjusting the distance between the reference sensing node and the calibration signal source, and measuring the distance of the reference sensing node before and after the distance adjustment in unit timeTResetting the number of falling edges by the inner step type output waveform, and calculating and solving the path loss factor of the radio propagation spacenThe calculation formula is as follows:
wherein the content of the first and second substances,r j1 to adjust the distance between the reference sensing node before calibration and the calibration signal source,r j2 in order to adjust the distance between the reference sensing node and the calibration signal source,N j1 for adjusting the reference sensing node in unit timeTThe inner stepped output waveform resets the number of falling edges,N j2 for adjusting the reference sensing node in unit timeTThe inner stepped output waveform resets the number of falling edges.
8. The method according to claim 7, wherein when the number of the sensing nodes is 4, the remaining three sensing nodes except the reference sensing node are substituted into the trilateration location algorithm of step S5 to locate the partial discharge source location;
and when the number of the set sensing nodes is more than 4, combining the other sensing nodes except the reference sensing node, wherein the three sensing nodes are one combination, substituting each combination into the trilateration positioning algorithm in the step S5 to obtain a positioning point, and calculating and positioning the position of the partial discharge source by using the positioning point obtained by each combination through the centroid.
9. Method for locating a uhf partial discharge point according to claim 6, characterized in that the unit of time isTCan meet the requirement of unit timeTAnd the step integration circuit and the reset circuit of the inner sensing node complete at least 100 times of charge-discharge reset.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210280331.XA CN114384383A (en) | 2022-03-22 | 2022-03-22 | Circuit and method for positioning ultrahigh frequency partial discharge point |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210280331.XA CN114384383A (en) | 2022-03-22 | 2022-03-22 | Circuit and method for positioning ultrahigh frequency partial discharge point |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114384383A true CN114384383A (en) | 2022-04-22 |
Family
ID=81206392
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210280331.XA Pending CN114384383A (en) | 2022-03-22 | 2022-03-22 | Circuit and method for positioning ultrahigh frequency partial discharge point |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114384383A (en) |
Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4567465A (en) * | 1982-05-25 | 1986-01-28 | Iwatsu Electric Co., Ltd. | Method and apparatus for converting analog signal into digital signal |
| JPH06174778A (en) * | 1992-12-03 | 1994-06-24 | Mitsubishi Electric Corp | Partial discharge detector |
| JP2010276420A (en) * | 2009-05-27 | 2010-12-09 | Mitsubishi Electric Corp | Device and method for detecting partial discharge |
| CN104062570A (en) * | 2014-07-14 | 2014-09-24 | 国家电网公司 | Power transformer partial discharge signal frequency-selecting method |
| CN104169730A (en) * | 2012-03-14 | 2014-11-26 | 东芝三菱电机产业系统株式会社 | Partial discharge measurement system and partial discharge measurement method by repeated impulse voltage |
| WO2015070513A1 (en) * | 2013-11-14 | 2015-05-21 | 国家电网公司 | Pattern recognition method for partial discharge of three-phase in one enclosure type ultrahigh voltage gis |
| CN109031073A (en) * | 2018-09-04 | 2018-12-18 | 苏州光格设备有限公司 | cable local discharge positioning device and method |
| CN109477881A (en) * | 2016-05-25 | 2019-03-15 | 弗劳恩霍夫应用研究促进协会 | Waveform Design for positioning system |
| CN109814005A (en) * | 2017-11-20 | 2019-05-28 | 云南电网有限责任公司玉溪供电局 | A kind of cable insulation defect recognition and localization method and system |
| CN110031729A (en) * | 2018-12-08 | 2019-07-19 | 全球能源互联网欧洲研究院 | Detection method, system and the data fusion analytical unit in local discharge signal source |
| CN112098748A (en) * | 2020-08-28 | 2020-12-18 | 国网山东省电力公司青岛供电公司 | Method for detecting partial discharge of switch cabinet of power distribution network by ultrahigh frequency sensor |
| CN112198400A (en) * | 2020-09-30 | 2021-01-08 | 国网福建省电力有限公司漳州供电公司 | High-voltage switch cabinet partial discharge online detection method based on spectrum sensing characteristic |
| CN113343169A (en) * | 2021-04-20 | 2021-09-03 | 云南电网有限责任公司临沧供电局 | Method for positioning defective equipment in open-type transformer substation |
| CN113884847A (en) * | 2021-08-11 | 2022-01-04 | 国网天津市电力公司电力科学研究院 | Large-dynamic-range partial discharge ultrahigh frequency signal detection circuit |
-
2022
- 2022-03-22 CN CN202210280331.XA patent/CN114384383A/en active Pending
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4567465A (en) * | 1982-05-25 | 1986-01-28 | Iwatsu Electric Co., Ltd. | Method and apparatus for converting analog signal into digital signal |
| JPH06174778A (en) * | 1992-12-03 | 1994-06-24 | Mitsubishi Electric Corp | Partial discharge detector |
| JP2010276420A (en) * | 2009-05-27 | 2010-12-09 | Mitsubishi Electric Corp | Device and method for detecting partial discharge |
| CN104169730A (en) * | 2012-03-14 | 2014-11-26 | 东芝三菱电机产业系统株式会社 | Partial discharge measurement system and partial discharge measurement method by repeated impulse voltage |
| WO2015070513A1 (en) * | 2013-11-14 | 2015-05-21 | 国家电网公司 | Pattern recognition method for partial discharge of three-phase in one enclosure type ultrahigh voltage gis |
| CN104062570A (en) * | 2014-07-14 | 2014-09-24 | 国家电网公司 | Power transformer partial discharge signal frequency-selecting method |
| CN109477881A (en) * | 2016-05-25 | 2019-03-15 | 弗劳恩霍夫应用研究促进协会 | Waveform Design for positioning system |
| CN109814005A (en) * | 2017-11-20 | 2019-05-28 | 云南电网有限责任公司玉溪供电局 | A kind of cable insulation defect recognition and localization method and system |
| CN109031073A (en) * | 2018-09-04 | 2018-12-18 | 苏州光格设备有限公司 | cable local discharge positioning device and method |
| CN110031729A (en) * | 2018-12-08 | 2019-07-19 | 全球能源互联网欧洲研究院 | Detection method, system and the data fusion analytical unit in local discharge signal source |
| CN112098748A (en) * | 2020-08-28 | 2020-12-18 | 国网山东省电力公司青岛供电公司 | Method for detecting partial discharge of switch cabinet of power distribution network by ultrahigh frequency sensor |
| CN112198400A (en) * | 2020-09-30 | 2021-01-08 | 国网福建省电力有限公司漳州供电公司 | High-voltage switch cabinet partial discharge online detection method based on spectrum sensing characteristic |
| CN113343169A (en) * | 2021-04-20 | 2021-09-03 | 云南电网有限责任公司临沧供电局 | Method for positioning defective equipment in open-type transformer substation |
| CN113884847A (en) * | 2021-08-11 | 2022-01-04 | 国网天津市电力公司电力科学研究院 | Large-dynamic-range partial discharge ultrahigh frequency signal detection circuit |
Non-Patent Citations (5)
| Title |
|---|
| JOSÉ MAURICIO NETO等: "Radiometric location of partial discharge sources for the future smart grid", 《2014 XXXITH URSI GENERAL ASSEMBLY AND SCIENTIFIC SYMPOSIUM (URSI GASS)》, 20 October 2014 (2014-10-20) * |
| ZHANG YONG等: "Radiometric Wireless Sensor Network Monitoring of Partial Discharge Sources in Electrical Substations", 《INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS》, 31 December 2015 (2015-12-31), pages 4 - 8 * |
| ZIQI YUE: "Location Determination of Partial Discharge Sources in Air-Insulated Substation", 《2021 INTERNATIONAL WIRELESS COMMUNICATIONS AND MOBILE COMPUTING (IWCMC)》, 9 August 2021 (2021-08-09) * |
| 何云强: "《电子线路设计、检验、测试使用手册 第2卷》", 31 May 2005, pages: 531 - 533 * |
| 卢结成等: "《电子电路试验及应用课题设计》", 31 March 2002, pages: 23 - 24 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107290564B (en) | Phase difference-based ultrasonic flow velocity measurement method | |
| CN109799434A (en) | PD Pattern Recognition system and method | |
| CN106324048B (en) | A kind of soil humidity sensor and its working method based on oscillation circuit | |
| CN108401445A (en) | For the circuit of time of measuring, method and related chip, system and equipment | |
| CN114384383A (en) | Circuit and method for positioning ultrahigh frequency partial discharge point | |
| CN104965158A (en) | Improved ultrahigh-frequency partial discharge capacity detection acquiring device and method | |
| JP4853699B2 (en) | Electric charge type accident investigation device | |
| CN203825190U (en) | Near-field electromagnetic ranging device | |
| CN108226910A (en) | Monomer sonac detection system | |
| US11143751B2 (en) | Sound sensing with time-varying thresholds | |
| US20220187351A1 (en) | Waveform measuring method | |
| CN111568419B (en) | Detection method, detector and terminal equipment | |
| CN114994418A (en) | Time domain measurement method for field intensity of repetition frequency change or frequency hopping pulse signal radiation field | |
| CN113484618A (en) | Pulse amplitude acquisition device and pulse amplitude acquisition method | |
| CN106685633A (en) | Full-digital phase shift weak signal phase lock detection method and equipment | |
| CN203502749U (en) | Pulse time interval measuring device | |
| US5153508A (en) | Method and apparatus for determining return stroke polarity of distant lightning | |
| CN205608178U (en) | Short range range radar system | |
| CN220043399U (en) | Comparison detection circuit | |
| CN219715755U (en) | Laser ranging data acquisition device | |
| CN218412774U (en) | Novel GIS equipment partial discharge monitoring sensing device | |
| CN216209456U (en) | Frequency measuring device | |
| KR101940299B1 (en) | Pulse radar and methdo for processing signal thereof | |
| RU27713U1 (en) | COAGENT-PULSE RADAR STATION | |
| CN218099369U (en) | Phase detection system and power detection system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |