CN110672902A - Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method - Google Patents
Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method Download PDFInfo
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- CN110672902A CN110672902A CN201910958850.5A CN201910958850A CN110672902A CN 110672902 A CN110672902 A CN 110672902A CN 201910958850 A CN201910958850 A CN 201910958850A CN 110672902 A CN110672902 A CN 110672902A
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/146—Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop
- G01R15/148—Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop involving the measuring of a magnetic field or electric field
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The invention discloses a magnetic field gathering assembly, a non-contact leakage current measuring device and a measuring method. The magnetic field gathering assembly adopts a four-air-gap structure, so that the width of a longitudinal air gap of the magnetic field gathering device is not limited by the size of the magnetic field sensor any more, the minimized width of the longitudinal air gap obviously improves the magnetic field intensity at the edge of the longitudinal air gap, the magnetic field sensor positioned in the transverse gap simultaneously measures two superposed edge magnetic fields, the measured magnetic field intensity is far greater than the magnetic field intensity of the traditional single-air-gap structure, the signal-to-noise ratio is improved, further, the leakage current with the effective value of only several milliamperes to hundreds of milliamperes can be measured, and the accuracy requirement of the ground leakage current measurement of.
Description
Technical Field
The invention relates to the field of measurement of earth leakage current of power equipment, in particular to a magnetic field gathering assembly, a non-contact leakage current measuring device and a measuring method.
Background
The intelligent and automatic operation and maintenance of the power equipment is always the development direction of the power grid technology, and at present, the big data and internet of things technology is greatly developed, so that the application range and the field of the on-line monitoring technology of the power equipment are greatly expanded. The insulation performance is related to the safe and reliable operation of power equipment, and is always the key point of the attention of an online monitoring technology. In particular, the monitoring of insulation resistance, relative dielectric loss value and other insulation performance related index parameters all require the measurement of the earth leakage current of the power equipment.
The measurement of the leakage current of the power equipment to the ground is always a difficult point for restricting the monitoring of the insulation performance of the power equipment because the effective value of the leakage current of the power equipment to the ground is only in the level of several milliamperes to hundreds of milliamperes and is in a strong magnetic field environment. In the past, the most common method for measuring the leakage current of the power equipment on line is to serially connect a zero-flux current transformer in a grounding loop of the power equipment and measure the grounding leakage current through the zero-flux current transformer. However, the method has exposed many problems in practical application, and therefore, at present, a non-contact type measuring system and a measuring method based on the current-magnetic field principle are gradually applied to measuring the earth leakage current of the power equipment installed on the supporting steel column, so that the power equipment does not need to be powered off when the device is installed, the structure of the power equipment and the electrical continuity of an original earth connection loop are not changed during operation, and the safety and the reliability of the measurement process of the earth leakage current of the power equipment are effectively improved.
However, the conventional non-contact measurement system mainly aims at a strong measurement signal, when the system is applied to measurement of ground leakage current of power equipment with an effective value of only several milliamperes to hundreds of milliamperes, measurement accuracy is often poor due to weak measurement signal, and in order to improve measurement accuracy, a plurality of high-precision signal processing circuits are usually added in a signal processing circuit board, so that signal processing steps are complicated, and production cost is high. For this reason, it is necessary to redesign the noncontact measurement system to meet the accuracy requirements of the measurement of the earth leakage current of the power equipment.
Disclosure of Invention
The invention aims to provide a magnetic field gathering assembly, a non-contact leakage current measuring device and a measuring method, which can remarkably improve the signal intensity measured by a magnetic field sensor under extremely weak current by redesigning the structure of the magnetic field gathering assembly, and can accurately and efficiently measure the ground leakage current of power equipment with an effective value of only several milliamperes to hundreds of milliamperes by optimizing the module and the data processing mode of a signal processing circuit board.
In the prior art, patent CN106093548A discloses a non-contact high-precision shaft current measuring device, which is used for measuring the shaft current of a ship, so that the corrosion prevention condition of the ship can be effectively known. The measuring device comprises a first magnetic gathering ring and a second magnetic gathering ring which are semi-circular, two air gaps at different positions are formed on the periphery of a measured shaft of the two magnetic gathering rings, a first magnetic sensor and a second magnetic sensor are respectively arranged in the two air gaps, the magnetic sensors which are symmetrically arranged measure magnetic fields in the air gaps by using a current-magnetic field principle, voltage signals representing the magnetic fields are output to a signal processing circuit board, and the signal processing circuit board calculates the current of the measured shaft after processing the voltage signals.
The patent CN106093548A applies to the magnetic poly ring structure, which is also called single air gap structure. In the single air gap structure, one magnetic sensor is placed in one air gap, that is, two magnetic sensors are respectively arranged between two air gaps for measuring the magnetic field in the air gap, and the direction of the magnetic field is generally from one magnet to the other magnet. In order to increase the measured magnetic field, the most effective and direct means is to reduce the air gap width as much as possible, thereby increasing the measured magnetic field and improving the signal-to-noise ratio. However, since the magnetic sensor needs to be placed in the air gap, the minimum width of the air gap is limited by the size of the magnetic sensor, and the size of the magnetic sensor is not limited by the signal to noise ratio improvement of the conventional magnetic field concentrator. For the current measurement common in patent CN106093548A, since the current is strong enough, the magnetic field is also strong enough, and there is no need to further improve the performance of the magnetic field concentrator. However, for a leakage current from the power device to the ground with a valid value of only several to hundreds of milliamperes, the strength of the measured magnetic field must be further increased.
Therefore, the inventor designs a four-air-gap structure, a magnetic sensor placed in a single longitudinal air gap in the prior art is placed at the intersection of the four air gaps, the magnetic field intensity of a detected magnetic field is obviously improved by utilizing the superposition of the magnetic fields of the upper longitudinal air gap edge, the lower longitudinal air gap edge, the inner longitudinal air gap edge and the outer longitudinal air gap edge, meanwhile, the width of the longitudinal air gap is not limited by the size of the magnetic sensor any more and can be far smaller than the size of the magnetic sensor, and the intensity of the detected magnetic field is greatly improved.
Specifically, the invention is realized by the following technical scheme:
the magnetic field gathering assembly comprises at least two concentrically arranged magnetic field concentrators, wherein longitudinal air gaps are formed in the magnetic field concentrators, a transverse air gap is formed between every two adjacent magnetic field concentrators, and the transverse air gap is used for placing a magnetic sensor.
The magnetic field gathering assembly in the technical scheme comprises at least two magnetic field gathering devices, each magnetic field gathering device is of an existing circular ring structure, and a longitudinal air gap is formed in each magnetic field gathering device, namely the air gap in a single magnetic gathering ring in the prior art. Because the magnetic field intensity in the longitudinal air gap is larger and more uniform, the traditional magnetic field sensor is placed in the longitudinal air gap to measure the magnetic field generated by current. To measure even weaker currents requires a further increase in magnetic field strength, and narrowing the width between the longitudinal air gaps is the most efficient and direct way to increase the magnetic field strength. However, the minimum value of the longitudinal air gap width is limited by the size of the magnetic field sensor placed inside, and therefore, if the longitudinal air gap width is further reduced, a thinner magnetic field sensor with high cost is required, which undoubtedly increases the production cost of the measuring device, and the method does not fundamentally solve the problem that the longitudinal air gap width is limited by the size of the magnetic field sensor.
In order to solve the above problems, the inventor has found through a lot of experiments and simulation that as the width of the longitudinal air gap is reduced, not only the magnetic field in the middle of the longitudinal air gap is enhanced, but also the magnetic field at the edges of the longitudinal air gap is significantly enhanced. Based on the characteristic, the invention adopts the mode that at least two magnetic field collectors are concentrically arranged, namely, the central axes of the magnetic field collectors penetrating through the circle center are collinear. The two magnetic field collectors are concentrically arranged, and the first one is that one magnetic field collector is positioned above the other magnetic field collector, and the other one is that one magnetic field collector is sleeved outside the other magnetic field collector. In any of the above-mentioned arrangements, a circular transverse air gap is formed between two adjacent magnetic field collectors, and the transverse air gap is opened along the circumferential direction of the magnetic field collectors, and the magnetic sensor is placed in the transverse air gap.
Compared with the prior art that the magnetic sensor is placed in the longitudinal air gap to measure the magnetic field, the magnetic field inside the transverse air gap is mainly the superposition of the magnetic fields leaked from the edges of the two longitudinal air gaps. The magnetic field sensor is arranged in the transverse air gap, so that the width of the longitudinal air gap is not limited by the size of the magnetic sensor any more, the width of the longitudinal air gap can be made as small as possible, for example, less than 1mm, and the magnetic field intensity of the longitudinal air gap is very sensitive to the change of the width of the longitudinal air gap, so that the magnetic field in the longitudinal air gap and the magnetic field at the edge of the longitudinal air gap can be remarkably enhanced after the width is reduced, and the magnetic induction intensity measured by the magnetic sensor in the transverse air gap is far greater than that of the traditional single air gap structure through the superposition of.
As a preferred structure of the present invention, the longitudinal air gaps of two adjacent magnetic sensors provided with the lateral air gaps of the magnetic sensors are aligned. As shown in figure 1, the magnetic field sensor is positioned between the longitudinal air gaps of the two magnetic field collectors, the magnetic field sensor divides the transverse air gap into two parts, so that a four-air-gap structure is formed, the magnetic field sensor is just positioned at the intersection of the transverse air gap and the longitudinal air gap, the magnetic field intensity of the edges of the two longitudinal air gaps at the intersection is maximized, and the magnetic field intensity to be measured can be obviously improved by superposing the magnetic fields at the two edges.
Preferably, the measuring direction of the magnetic field sensor is arranged in parallel with the direction of the measured magnetic field to further improve the magnetic field strength.
Preferably, the magnetic core material of the magnetic field concentrator is nanocrystalline.
Through the arrangement, the longitudinal air gap width of the magnetic field collector is not limited by the size of the magnetic field sensor any more, the minimized longitudinal air gap width obviously improves the magnetic field intensity at the longitudinal air gap edge, the magnetic field sensor positioned in the transverse gap simultaneously measures two superposed edge magnetic fields, the measured magnetic field intensity is far greater than the magnetic field intensity of the traditional single air gap structure, the signal-to-noise ratio is improved, and then the leakage current with the effective value of only several milliamperes to hundreds milliamperes can be measured, and the precision requirement of the power equipment on the measurement of the ground leakage current is met.
According to the actual use requirement, the number of the magnetic field collectors in the magnetic field collecting assembly can be only two, or more than two, and the number of the longitudinal air gaps on each magnetic field collector can be one or more.
Preferably, in order to reduce production costs, the magnetic field concentration assembly of the present invention preferably employs two concentrically arranged magnetic field concentrators.
As a preferred embodiment of the magnetic field concentrator assembly according to the invention, the magnetic field concentrator comprises a first magnetic field concentrator and a second magnetic field concentrator located above the first magnetic field concentrator, the first magnetic field concentrator and the second magnetic field concentrator are each provided with two longitudinal air gaps, the two longitudinal air gaps are symmetrically arranged with respect to a central axis of the magnetic field concentrator, and a transverse air gap is provided between the first magnetic field concentrator and the second magnetic field concentrator. A transverse air gap is formed between the first magnetic field collector and the second magnetic field collector, two longitudinal air gaps which are symmetrically arranged about the central axis of the first magnetic field collector are arranged on the first magnetic field collector, and two longitudinal air gaps which are symmetrically arranged about the central axis of the second magnetic field collector are arranged on the second magnetic field collector. Preferably, the longitudinal air gaps on the first magnetic field concentrator are aligned one-to-one with the longitudinal air gaps on the second magnetic field concentrator, forming two four air gap structures symmetrically arranged about the central axis of the magnetic field concentrator, said four air gap structures being used for placing the magnetic field sensors.
As another preferred embodiment of the magnetic field concentrator assembly according to the invention, the magnetic field concentrator comprises a first magnetic field concentrator, and a second magnetic field concentrator located outside the first magnetic field concentrator, wherein the first magnetic field concentrator and the second magnetic field concentrator are each provided with two longitudinal air gaps, the two longitudinal air gaps are symmetrically arranged with respect to a central axis of the magnetic field concentrator, and a transverse air gap is provided between the first magnetic field concentrator and the second magnetic field concentrator. The second magnetic field concentrator has an inner diameter larger than an outer diameter of the first magnetic field concentrator. In a similar way to the up and down placement, a transverse air gap is formed between the first magnetic field collector and the second magnetic field collector, the first magnetic field collector is provided with two longitudinal air gaps symmetrically arranged with respect to the central axis of the first magnetic field collector, and the second magnetic field collector is provided with two longitudinal air gaps symmetrically arranged with respect to the central axis of the second magnetic field collector. Preferably, the longitudinal air gaps on the first magnetic field concentrator are aligned one-to-one with the longitudinal air gaps on the second magnetic field concentrator, forming two four air gap structures symmetrically arranged about the central axis of the magnetic field concentrator, said four air gap structures being used for placing the magnetic field sensors.
Further, the width of the transverse air gap is not more than 5mm, and the width of the longitudinal air gap is not more than 1 mm. Preferably, the width of the transverse air gap can be controlled to be 2-3 mm, and the transverse air gap is enough to be placed into a signal processing circuit board and a sensor chip; the width of the longitudinal air gap can be reduced to 0.5-1.0 mm according to the current processing technology.
The invention also provides a non-contact leakage current measuring device based on the magnetic field gathering assembly. The measuring device comprises a housing in which a first magnetic field concentrator, a first magnetic sensor, a second magnetic sensor and a signal processing circuit are arranged, as in the prior art.
Different from the prior art, the magnetic field gathering assembly of the measuring device is composed of two magnetic field gathering devices, and two symmetrically arranged four-air-gap structures are formed to place the first magnetic sensor and the second magnetic sensor.
Specifically, a second magnetic field collector and a partition plate are further arranged in the housing, the partition plate is used for separating the first magnetic field collector and the second magnetic field collector, the first magnetic field collector and the second magnetic field collector are concentrically arranged, two longitudinal air gaps are respectively arranged on the first magnetic field collector and the second magnetic field collector, a transverse air gap is arranged between the first magnetic field collector and the second magnetic field collector, the first magnetic sensor, the second magnetic sensor and the signal processing circuit are positioned in the transverse air gap, the first magnetic sensor and the second magnetic sensor are positioned between the longitudinal air gap of the first magnetic field collector and the longitudinal air gap of the second magnetic field collector, and the first magnetic sensor and the second magnetic sensor are symmetrically arranged about a central axis of the magnetic field collector; the first magnetic sensor and the second magnetic sensor are used for measuring a magnetic field in a transverse air gap and outputting a voltage signal representing the magnetic field, and the signal processing circuit is used for receiving the voltage signal, processing the voltage signal and outputting a measurement result.
The arrangement of the first magnetic field collector and the second magnetic field collector also includes an up-down arrangement and an in-out arrangement.
The housing is used for fixing the first magnetic field collector and the second magnetic field collector, so that the relative positions of the first magnetic field collector and the second magnetic field collector are fixed and unchanged, and in addition, the housing also provides protection for components such as a magnetic field sensor, a magnetic field collector, a signal processing circuit and the like in the housing, so that the long-term stable operation of the first magnetic field collector and the second magnetic field collector is ensured. A partition is arranged inside the housing, said partition being adapted to separate the first magnetic field concentrator from the second magnetic field concentrator. For the way of the first magnetic field collector and the second magnetic field collector being arranged up and down, the baffle is horizontally arranged inside the housing, and divides the housing into an upper part and a lower part to respectively contain the second magnetic field collector and the first magnetic field collector; for the first magnetic field concentrator and
and the second magnetic field collector is arranged inside and outside, and the partition plate is vertically arranged inside the shell and divides the shell into an inner part and an outer part so as to respectively contain the first magnetic field collector and the second magnetic field collector. At the intersection of the transverse air gap and the longitudinal air gap, namely, at the four-air-gap structure, the partition board is provided with a mounting groove for fixedly mounting the first magnetic sensor and the second magnetic sensor, and similarly, the partition board is also provided with a mounting groove for mounting the signal processing circuit board and other electrical components. The shell adopts split type structure, and preferably, the shell comprises two symmetrical semicircle ring casings, all is equipped with half first magnetic field collector and half second magnetic field collector in each semicircle ring casing, and when two casings joint on the steel column, the shell surface is sealed, forms two vertical air gaps on first magnetic field collector, the second magnetic field collector respectively. The two shells are detachably connected, and preferably, the two shells are connected in a threaded manner. Specifically, all be provided with the mounting bracket on two casings, pass the screw on the mounting bracket of two casings in order to realize the fastening through fastening bolt.
The first magnetic sensor and the second magnetic sensor are respectively positioned in two centrosymmetric four-air-gap structures, and the superposed fringe magnetic fields of the upper longitudinal air gap, the lower longitudinal air gap, the inner longitudinal air gap and the outer longitudinal air gap are measured to obtain stronger magnetic induction intensity under weak current and send stronger voltage signals to the signal processing circuit, and the signal processing circuit receives the voltage signals, processes the voltage signals and outputs measurement results.
In some embodiments, a power supply module is further disposed in the housing, and the power supply module is configured to supply power to each component of the non-contact leakage current measurement device. In some embodiments, the power supply module may also be an external component located outside the housing.
Experiments and simulation show that as the non-contact leakage current measuring device adopts the four-air-gap structure, for the leakage current of 200mA flowing in a steel column with the diameter of 300mm, the magnetic induction intensity at the intersection of the transverse air gap and the longitudinal air gap of the four-air-gap structure, namely the position where the magnetic sensor is placed, can be increased from 100-200mGs to 1000-1200mGs in the prior art, and the signal-to-noise ratio and the sensitivity of the magnetic sensor are obviously improved. Moreover, the remarkably improved magnetic induction intensity enables the non-contact leakage current measuring device provided by the invention to avoid designing a setting/resetting circuit to reset the magnetic domain inside the sensor as in a signal circuit processing board of patent CN106093548A, so that the sensitivity is improved, the design and processing steps of the signal processing circuit are effectively simplified, the production cost is reduced, the signal processing efficiency is improved, and the non-contact leakage current measuring device has a wide application value.
In the prior art, after receiving voltage signals sent by two magnetic sensors, a signal processing circuit performs signal superposition operation after performing differential amplification on the voltage signals, and the signal calculation mode is shown in fig. 7. The two output ports of the first magnetic sensor output differential voltage signals V respectively1+And V1-Two output ports of the second magnetic sensor output differential voltage signals V respectively2+And V2-. Wherein:
V1+＝VB/2+V1I/2+VD/2
V1-＝VB/2-V1I/2-VD/2
V2+＝VB/2+V2I/2+(-VD/2)
V2-＝VB/2-V2I/2-(-VD/2)
in the above formula, VBBridge voltage, V, of the first/second magnetic sensorsDThe output V of the first magnetic sensor is used for correspondingly measuring the output voltage signal for the geomagnetic field and the interference magnetic field1+、V1-Potential is VBA pair of differential signals with vertically symmetrical potential, V1IThe output V of the second magnetic sensor is measured for the measured current corresponding to the output voltage signal of the first magnetic sensor2+、V2-Potential is VBA pair of differential signals with vertically symmetrical potential, V2IAn output voltage signal is measured for the measured current corresponding to the second magnetic sensor.
The first magnetic sensor and the second magnetic sensor are respectively input and connected into a differential circuit to convert a differential mode signal into a common mode signalOutput, i.e. two input potentials V1+、V1-(V2+、V2-) Subtracting to obtain:
V1＝V1I+VD
V2＝V2I-VD
then, the differential circuit inputs are respectively connected into an addition circuit to be added, and the measurement component caused by the magnetic field can be removed:
V＝V1+V2＝V1I+V2I
the existing signal calculation mode has problems when applied to weak current measurement. When the non-contact leakage current measuring device is used for measurement, the induced magnetic field intensity is obviously enhanced by the structure of the four air gaps, the earth magnetic field signal is correspondingly amplified while the weak current signal is amplified, the weak current corresponds to a magnetic field which is extremely small and even is several times smaller than the earth magnetic field, and if the weak magnetic field is amplified to a target level, the earth magnetic field also reaches the target level by several times, so that the range of a power supply of an amplifying circuit is possibly exceeded, the output of the amplifying circuit is saturated, and a high requirement is provided for the power supply of the amplifying circuit. For example, the weak signal is 25mV, the earth magnetic field signal is 500mV, and in order to meet the processing requirement of a later stage circuit, the weak current signal is amplified by 40 times to 1V, and the earth magnetic field signal is also amplified by 40 times to 20V in theory, so that the requirement that the power supply of the amplifier is set to be the theoretical one
However, the maximum power supply of a general signal conditioning circuit or a finished product power supply module is ± 12V, and in order to measure weak current in this way, additional power supply design is required, which increases cost.
In order to solve the above problem, a signal processing circuit is adapted to the measurement of a weak current signal. The invention puts the signal superposition operation step in the signal processing circuit before the differential amplification step. Specifically, after the signal processing circuit receives voltage signals output by the first magnetic sensor and the second magnetic sensor, the voltage signals are sequentially subjected to signal following, signal superposition operation, differential amplification and filtering processing, and then measurement results are output. The voltage signal firstly enters the signal following circuit to realize signal isolation, so that the normal operation performance of a bridge circuit in the magnetic field sensor is not influenced by a post-stage signal processing circuit; adding voltage signals by signal superposition operation, removing the influence of a geomagnetic field and an external interference magnetic field, and obtaining an output signal of the sensor corresponding to the measured current by a signal differential amplification circuit; and the band-pass filter circuit is used for further removing direct current and high-frequency components in the signal.
In some embodiments, the sensor further comprises a signal calibration circuit, the filtered measured current is input into the calibration circuit corresponding to the output signal of the sensor, and after the calibration test, the sensitivity coefficient and the magnetic induction coefficient are compensated, and the sensor analog quantity is output. Besides direct output, the sensor analog quantity is converted into corresponding digital quantity through AD sampling and input into a digital signal processing unit. The digital signal processing unit is built by an ARM + FPGA framework, outputs a clock synchronization sampling value signal after the clock synchronization signal is accessed, and inputs a sampling value message through the communication module.
Further, the invention redesigns the signal superposition operation step, which specifically comprises: for the differential voltage signal V output by the first magnetic sensor1+And V1-The second magnetic sensor outputs a differential voltage signal sum V2+And V2-Will V1+And V2+Adding to obtain a high-end potential V+，V1-And V2-Adding to obtain a low-end potential V-Then, the high-end potential V is set+And a low-side potential V-Are added to obtain a voltage signal V. As shown in fig. 8, the high terminals of the first and second magnetic sensors are simultaneously input to the high terminal of the differential circuit, and the low terminals of the first and second magnetic sensors are simultaneously input to the low terminal of the differential circuit, where the high-terminal input terminal potential of the differential circuit is the sum of the high-terminal potentials of the two magnetic sensors, and the low-terminal input terminal potential of the differential circuit is the sum of the low-terminal potentials of the two magnetic sensors, that is, the high-terminal potential of the differential circuit is the sum of the low-terminal potentials of the
V+＝V1++V2+＝VB+V1I/2+V2I/2
V-＝V1-+V2-＝VB-V1I/2-V2I/2
Before inputting into the differential circuit, the high end and the low end of the magnetic sensor are butt-jointed for inputting, the high end potential and the low end potential of the earth magnetic field and the interference signal are respectively offset, when inputting into the differential circuit, there is no component of the earth magnetic field signal, only the superposed component is VBThe bridge voltage direct current component belongs to a common mode signal, and the component is automatically counteracted after being processed by the differential amplifying circuit, and cannot influence the detected signal and the differential circuit.
Then, the butted high and low ends are added through a differential circuit respectively, and the output result is obtained as follows:
V＝V+-V-＝V1I+V2I
it follows that, due to the input signal V+And V-The power supply does not contain geomagnetic field and interference magnetic field components, and fundamentally solves the problem that the amplifying circuit is saturated due to overlarge geomagnetic field and interference magnetic field components which are possibly generated during the design of a circuit power supply. Not only so, because through high-end, low-end butt joint respectively, earth magnetic field and interference component are eliminated voluntarily, and the difference of sensor signal is gathered just to a differential amplifier of whole circuit needs only, compares in the traditional mode and needs the circuit design who adopts two differential amplifiers and an addition amplifier, has practiced thrift the cost, has simplified circuit structure, has reduced the link that probably introduces the error.
Furthermore, a temperature sensor is further arranged in the shell, the temperature sensor is used for detecting the operating temperature of the first magnetic sensor and/or the second magnetic sensor and sending temperature data to the signal processing circuit, and the signal processing circuit carries out temperature compensation on voltage signals output by the first magnetic sensor and the second magnetic sensor. The temperature sensor is arranged near the magnetic sensor and used for detecting the operating temperature of the magnetic sensor, meanwhile, the temperature sensor is electrically connected with the signal processing circuit and used for sending a temperature data signal to the signal processing circuit, and the temperature drift of the magnetic sensor is compensated through a compensation algorithm. Preferably, the temperature compensation module is located between the signal following module and the signal superposition operation module. The temperature correction curve is compensated according to a quadratic coefficient, and the compensation formula is as follows:
Ux25＝Ux+a(T-25)2+b(T-25)
wherein, Ux25To calibrate the output signal of the first/second magnetic sensor at temperature, UxRaw output signal value (V) for first/second magnetic sensors1+,V1-,V2+,V2-) T is the temperature corresponding to the output signal of the temperature sensor, and a and b are the temperature compensation coefficients of the first and second magnetic sensors, which are determined by the properties of the first and second magnetic sensors.
Through the arrangement, the sensitivity compensation can be carried out on the output signal of the magnetic sensor according to the voltage signal of the magnetic sensor, the corresponding sensitivity of the output signal is ensured, the sensitivity is always 25 ℃ at the calibration temperature, and the accuracy of the measurement result is further improved.
The invention also provides a measuring method based on any one of the non-contact leakage current measuring devices, which comprises the following steps:
the method comprises the following steps: fixedly mounting the non-contact leakage current measuring device outside the steel column to be measured;
step two: the first magnetic sensor outputs a differential voltage signal V to the signal processing circuit1+And V1-The second magnetic sensor outputs a differential voltage signal V to the signal processing circuit2+And V2-；
Step three: the signal processing circuit converts V1+And V2+Adding to obtain a high-end potential V+Will V1-And V2-Adding to obtain a low-end potential V-And high end potential V is adjusted+And a low-side potential V-Adding to obtain a voltage signal V;
step four: and carrying out differential amplification and filtering processing on the voltage signal V and then outputting the voltage signal V.
The measuring method utilizes the unique four-air-gap structure design of the non-contact leakage current measuring device, so that the strength of a measured magnetic field is far greater than that of the magnetic field of a traditional single-air-gap structure, the signal-to-noise ratio is improved, the leakage current with an effective value of only several milliamperes to hundreds of milliamperes can be measured, the precision requirement of the power equipment on the ground leakage current measurement is met, meanwhile, the design and processing steps of a signal processing circuit are effectively simplified, the production cost is reduced, and meanwhile, the signal processing efficiency is improved. In addition, the signal superposition operation step is moved to the front of the differential amplification step, and the signal calculation mode is changed, so that the signal processing circuit is further simplified, the manufacturing cost is effectively reduced, the links which possibly introduce errors are reduced, and the problem of the saturation of the amplification circuit caused by overlarge geomagnetic field and interference magnetic field components which are possibly generated during the circuit power supply design is fundamentally solved.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. the magnetic field gathering assembly adopts a four-air-gap structure, so that the width of a longitudinal air gap of the magnetic field gathering device is not limited by the size of a magnetic field sensor any more, the minimized width of the longitudinal air gap obviously improves the magnetic field intensity at the edge of the longitudinal air gap, the magnetic field sensor positioned in a transverse gap simultaneously measures two superposed edge magnetic fields, the measured magnetic field intensity is far greater than the magnetic field intensity of the traditional single-air-gap structure, the signal-to-noise ratio is improved, and further, the leakage current with an effective value of only several milliamperes to hundreds milliamperes can be measured, and the accuracy requirement of the measurement of the ground leakage current of;
2. the non-contact leakage current measuring device adopts two concentrically arranged magnetic field collectors, and the magnetic sensors are arranged in two symmetrically arranged four-air-gap structures, so that the magnetic induction intensity of the position where the magnetic sensors are arranged can be increased to 1000-1200mGs from 100-200mGs in the prior art, and the signal-to-noise ratio and the sensitivity of the magnetic sensors are obviously improved;
3. the non-contact leakage current measuring device obviously improves the magnetic induction intensity, so that a setting/resetting circuit does not need to be designed to reset the magnetic domain inside the sensor like the prior art, and the sensitivity is further improved, thereby effectively simplifying the design and processing steps of a signal processing circuit, reducing the production cost, improving the signal processing efficiency and having wide application value;
4. the signal processing circuit optimizes the signal calculation mode, further simplifies the circuit structure, saves the cost, simplifies the circuit structure and reduces the links which possibly introduce errors on the one hand, and on the other hand, because the input signal V is input+And V-The power supply does not contain a geomagnetic field and an interference magnetic field component, so that the problem of saturation of an amplifying circuit caused by overlarge geomagnetic field and interference magnetic field components which are possibly generated in the design of a circuit power supply is fundamentally solved;
5. according to the invention, by arranging the temperature sensor, the sensitivity compensation can be carried out on the output signal of the magnetic sensor according to the voltage signal of the magnetic sensor, the corresponding sensitivity of the output signal is ensured, the sensitivity is always calibrated at the temperature of 25 ℃, and the accuracy of the measurement result is further improved.
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 a schematic diagram of a four-gap configuration of the present invention;
FIG. 2 is a schematic diagram of a magnetic field focusing assembly according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of another magnetic field focusing assembly in accordance with an embodiment of the present invention;
FIG. 4 is a schematic view of a non-contact current measuring device mounted on a steel column for measurement according to an embodiment of the present invention;
FIG. 5 is a cross-sectional view of a non-contact current measuring device in an embodiment of the present invention;
FIG. 6 is a schematic diagram of a non-contact current measuring device according to an embodiment of the present invention;
FIG. 7 is a block diagram of a signal calculation method in a measurement method according to the prior art;
fig. 8 is a block diagram illustrating a signal calculation method of the signal processing circuit according to an embodiment of the present invention.
Reference numbers and corresponding part names in the drawings:
1-a first magnetic field collector, 2-a second magnetic field collector, 3-a longitudinal air gap, 4-a transverse air gap, 5-a first magnetic sensor, 6-a second magnetic sensor, 7-a temperature sensor, 8-a shell, 9-a clapboard, 10-a steel column, 11-a mounting frame and 12-a fastening bolt.
Detailed Description
In order 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 examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not used as limitations of the present invention.
In the description of the present invention, it is to be understood that the terms "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. indicate orientations and positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of 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 therefore, should not be taken as limiting the scope of the present invention.
Example 1:
the magnetic field concentrator of the magnetic field concentrating assembly shown in fig. 2 comprises a first magnetic field concentrator 1 and a second magnetic field concentrator 2 located above the first magnetic field concentrator 1, wherein the first magnetic field concentrator 1 and the second magnetic field concentrator 2 are respectively provided with two longitudinal air gaps 3, the two longitudinal air gaps 3 are symmetrically arranged about a central axis of the magnetic field concentrator, and a transverse air gap 4 is arranged between the first magnetic field concentrator 1 and the second magnetic field concentrator 2; the longitudinal air gap 3 of the first magnetic field concentrator 1 is aligned with the longitudinal air gap 3 of the second magnetic field concentrator 2.
As shown in fig. 1 and 2, at this time, the first magnetic field sensor 5 and the second magnetic field sensor 6 are respectively located between the longitudinal air gaps of the two magnetic field concentrators, and the magnetic field sensor divides the transverse air gap into two parts, so that two four-air-gap structures symmetrical about the central axis are formed, the magnetic field sensor is just located at the intersection of the transverse air gap and the longitudinal air gap, the magnetic field intensity at the edges of the two longitudinal air gaps at the intersection is maximized, and the magnetic field intensity to be measured can be remarkably improved by superposing the magnetic fields at the two edges.
Experiments and simulation show that when the leakage current of 200mA flowing through a steel column with the diameter of 300mm is measured, if a magnetic field sensor needs an air gap of 5mm according to the size of the magnetic field sensor, nanocrystalline is used as a magnetic core material, a traditional magnetic concentrator single-air-gap structure is adopted, the air gap is at least 5mm, the magnetic induction intensity in the middle of the air gap can reach the range of 100-200mGs when the magnetic induction intensity is calculated by the section of a magnetic field concentrator being 30mm multiplied by 15 mm.
If a four-air-gap structure is applied, and under the condition of 5mm air gaps, 2 groups of magnetic field concentrators with 15mm multiplied by 15mm cross sections (2 groups of the magnetic field concentrators with 15mm multiplied by 15mm cross sections have the same volume with the traditional 30mm multiplied by 15mm cross sections) form the four-air-gap structure, because the magnetic fields of the upper and lower groups of the magnetic field concentrators are superposed, the magnetic induction intensity at the intersection of a transverse air gap and a longitudinal air gap, namely the position where a sensor is placed, can reach the range of 180-350 mGs, and the superposition of edge magnetic fields can obtain the magnetic induction intensity stronger than that in the longitudinal air gap of the single-air-gap.
Because a magnetic sensor is not required to be placed in the longitudinal air gap, the width of the longitudinal air gap of the four-air-gap structure is further shortened to 1mm, and the magnetic induction intensity at the intersection of the transverse air gap and the longitudinal air gap can reach the range of 1000-1200mGs because the increase of the magnetic induction intensity of the air gap is greatly influenced by the reduction of the width of the longitudinal air gap.
Therefore, the four-air-gap structure enables the width of a longitudinal air gap of the magnetic field collector to be not limited by the size of the magnetic field sensor any more, the minimized width of the longitudinal air gap obviously improves the magnetic field intensity at the edge of the longitudinal air gap, the magnetic field sensor positioned in the transverse gap simultaneously measures two superposed edge magnetic fields, the measured magnetic field intensity is far greater than the magnetic field intensity of the traditional single-air-gap structure, the signal-to-noise ratio is improved, the leakage current with the effective value of only several milliamperes to hundreds milliamperes can be measured, and the accuracy requirement of the measurement of the ground leakage current of the power equipment is met.
In some embodiments, the width of the transverse air gap 4 is not greater than 5mm, and the width of the longitudinal air gap 3 is not greater than 1 mm.
In some embodiments, the measuring direction of the magnetic field sensor is parallel to the direction of the measured magnetic field to further improve the magnetic field strength.
In some embodiments, the number of the magnetic field collectors in the magnetic field collecting assembly may be only two, or more than two, and the number of the longitudinal air gaps on each magnetic field collector may be one or more.
Example 2:
as shown in fig. 3, another magnetic field collecting assembly of the present invention comprises a first magnetic field collector 1, and a second magnetic field collector 2 located outside the first magnetic field collector 1, wherein the first magnetic field collector 1 and the second magnetic field collector 2 are each provided with two longitudinal air gaps 3, the two longitudinal air gaps 3 are symmetrically arranged with respect to a central axis of the magnetic field collector, and a transverse air gap 4 is provided between the first magnetic field collector 1 and the second magnetic field collector 2.
In some embodiments, the width of the transverse air gap 4 is not greater than 5mm, and the width of the longitudinal air gap 3 is not greater than 1 mm.
In some embodiments, the measuring direction of the magnetic field sensor is parallel to the direction of the measured magnetic field to further improve the magnetic field strength.
In some embodiments, the number of the magnetic field collectors in the magnetic field collecting assembly may be only two, or more than two, and the number of the longitudinal air gaps on each magnetic field collector may be one or more.
Example 3:
a non-contact leakage current measuring device comprises a housing 8, a first magnetic field collector 1, a first magnetic sensor 5, a second magnetic sensor 6 and a signal processing circuit are arranged in the housing 8, a second magnetic field collector 2 and a partition plate 9 are further arranged in the housing 8, the partition plate 9 is used for separating the first magnetic field collector 1 from the second magnetic field collector 2, the first magnetic field collector 1 and the second magnetic field collector 2 are concentrically arranged, two longitudinal air gaps 3 are respectively arranged on the first magnetic field collector 1 and the second magnetic field collector 2, a transverse air gap 4 is arranged between the first magnetic field collector 1 and the second magnetic field collector 2, the first magnetic sensor 5, the second magnetic sensor 6 and the signal processing circuit are arranged in the transverse air gap 4, the first magnetic sensor 5 and the second magnetic sensor 6 are arranged between the longitudinal air gap 3 of the first magnetic field collector 1 and the longitudinal air gap 3 of the second magnetic field collector 2, and the first magnetic sensor 5 and the second magnetic sensor 6 are symmetrically arranged with respect to the central axis of the magnetic field concentrator; the first magnetic sensor 5 and the second magnetic sensor 6 are configured to measure a magnetic field in the transverse air gap 4 and output a voltage signal representing the magnetic field, and the signal processing circuit is configured to receive the voltage signal, process the voltage signal, and output a measurement result.
When the first magnetic field collector and the second magnetic field collector are placed in the up and down manner as shown in FIG. 2, as shown in FIG. 4, the partition plate 9 is horizontally disposed inside the housing 8 to divide the housing into an upper portion and a lower portion to accommodate the second magnetic field collector and the first magnetic field collector, respectively. When the first magnetic field collector and the second magnetic field collector are placed inside and outside as shown in fig. 3, the partition plate 9 is vertically disposed inside the housing as shown in fig. 5, dividing the housing into an inner portion and an outer portion to accommodate the first magnetic field collector and the second magnetic field collector, respectively. In any way, at the intersection of the transverse air gap and the longitudinal air gap, namely, at the four-air-gap structure, the partition board is provided with a mounting groove for fixedly mounting the first magnetic sensor and the second magnetic sensor, and similarly, the partition board is also provided with a mounting groove for mounting the signal processing circuit board and other electrical components.
The shell adopts a split structure, as shown in fig. 5, the shell is composed of two symmetrical semi-circular shell bodies, a half of the first magnetic field collector and a half of the second magnetic field collector are arranged in each semi-circular shell body, when the two shell bodies are clamped on the steel column, the outer surface of the shell is closed, and two longitudinal air gaps are respectively formed on the first magnetic field collector and the second magnetic field collector. The two shells are preferably connected in a threaded manner. All be provided with mounting bracket 11 on two casings, all be provided with the screw on the mounting bracket, pass the screw on the mounting bracket of two casings in order to realize the fastening connection through fastening bolt 12.
In some embodiments, a power supply module is further disposed in the housing, and the power supply module is configured to supply power to each component of the non-contact leakage current measurement device. In some embodiments, the power supply module may also be an external component located outside the housing.
In the technical scheme, the magnetic induction intensity is obviously improved by utilizing the four-air-gap structure, so that a setting/resetting circuit is not required to be designed to reset the magnetic domain in the sensor and further improve the sensitivity like the prior art, thereby effectively simplifying the design and processing steps of a signal processing circuit, reducing the production cost and improving the signal processing efficiency, and having wide application value.
Example 4:
on the basis of the above embodiment, as shown in fig. 6, after the signal processing circuit receives the voltage signals output by the first magnetic sensor 5 and the second magnetic sensor 6, the voltage signals are sequentially subjected to signal following, signal superposition operation, differential amplification and filtering processing, and then measurement results are output. The signal superposition operation step specifically comprises: with respect to the differential voltage signal V output from the first magnetic sensor 51+And V1-The second magnetic sensor 6 outputs the differential voltage signal sum V2+And V2-Will V1+And V2+Adding to obtain a high-end potential V+，V1-And V2-Adding to obtain a low-end potential V-Then, the high-end potential V is set+And a low-side potential V-Are added to obtain a voltage signal V.
As shown in fig. 7 to 8, compared with the prior art, the input signal V is input+And V-The power supply does not contain the earth magnetic field and the interference magnetic field component, and fundamentally solves the problem that the amplifying circuit is saturated due to the overlarge earth magnetic field and interference magnetic field component which are possibly generated in the design of a circuit power supply. Moreover, because the high end and the low end are respectively butted, the earth magnetic field and the interference component are automatically eliminated,the whole circuit can realize differential acquisition of sensor signals only by one differential amplifier, and compared with the circuit design that two differential amplifiers and one addition amplifier are needed in the traditional mode, the circuit has the advantages of saving cost, simplifying circuit structure and reducing links which can introduce errors.
In the signal processing circuit, a voltage signal firstly enters the signal following circuit to realize signal isolation and ensure that the later-stage signal processing circuit does not influence the normal operation performance of a bridge circuit in the magnetic field sensor; adding voltage signals by signal superposition operation, removing the influence of a geomagnetic field and an external interference magnetic field, and obtaining an output signal of the measured current corresponding to the sensor through a signal differential amplification circuit; and the band-pass filter circuit is used for further removing direct current and high-frequency components in the signal.
In some embodiments, the sensor further comprises a signal calibration circuit, the filtered measured current is input into the calibration circuit corresponding to the output signal of the sensor, and after the calibration test, the sensitivity coefficient and the magnetic induction coefficient are compensated, and the sensor analog quantity is output. Besides direct output, the sensor analog quantity is converted into corresponding digital quantity through AD sampling and input into a digital signal processing unit. The digital signal processing unit is built by an ARM + FPGA framework, outputs a clock synchronization sampling value signal after the clock synchronization signal is accessed, and inputs a sampling value message through the communication module.
Example 5:
as shown in fig. 2, in addition to the above embodiment, a temperature sensor 7 is further disposed in the housing 8, and the temperature sensor 7 is configured to detect an operating temperature of the first magnetic sensor 5 and/or the second magnetic sensor 6 and send temperature data to a signal processing circuit, which performs temperature compensation on the voltage signals output by the first magnetic sensor 5 and the second magnetic sensor 6.
The temperature correction curve is compensated according to a quadratic coefficient, and the compensation formula is as follows:
Ux25＝Ux+a(T-25)2+b(T-25)
wherein, Ux25To calibrate the output signal of the first/second magnetic sensor at temperature, UxRaw output signal value (V) for first/second magnetic sensors1+,V1-,V2+,V2-) T is the temperature corresponding to the output signal of the temperature sensor, and a and b are the temperature compensation coefficients of the first and second magnetic sensors, which are determined by the properties of the first and second magnetic sensors.
Through the arrangement, the sensitivity compensation can be carried out on the output signal of the magnetic sensor according to the voltage signal of the magnetic sensor, the corresponding sensitivity of the output signal is ensured, the sensitivity is always 25 ℃ at the calibration temperature, and the accuracy of the measurement result is further improved.
Example 6:
a measuring method based on any one of the non-contact leakage current measuring devices in the above embodiments, comprising the steps of:
the method comprises the following steps: fixedly mounting the non-contact leakage current measuring device outside the steel column to be measured 10;
step two: the first magnetic sensor 5 outputs a differential voltage signal V to the signal processing circuit1+And V1-The second magnetic sensor 6 outputs a differential voltage signal V to the signal processing circuit2+And V2-；
Step three: the signal processing circuit converts V1+And V2+Adding to obtain a high-end potential V+Will V1-And V2-Adding to obtain a low-end potential V-And high end potential V is adjusted+And a low-side potential V-Adding to obtain a voltage signal V;
step four: and carrying out differential amplification and filtering processing on the voltage signal V and then outputting a measurement result.
The measuring method utilizes the unique four-air-gap structure design of the non-contact leakage current measuring device, so that the strength of a measured magnetic field is far greater than that of the magnetic field of a traditional single-air-gap structure, the signal-to-noise ratio is improved, the leakage current with an effective value of only several milliamperes to hundreds of milliamperes can be measured, the precision requirement of the power equipment on the ground leakage current measurement is met, meanwhile, the design and processing steps of a signal processing circuit are effectively simplified, the production cost is reduced, and meanwhile, the signal processing efficiency is improved. In addition, the signal superposition operation step is moved to the front of the differential amplification step, and the signal calculation mode is changed, so that the signal processing circuit is further simplified, the manufacturing cost is effectively reduced, the links which possibly introduce errors are reduced, and the problem of the saturation of the amplification circuit caused by overlarge geomagnetic field and interference magnetic field components which are possibly generated during the circuit power supply design is fundamentally solved.
As used herein, "first", "second", etc. (e.g., first magnetic field concentrator, second magnetic field concentrator, first magnetic sensor, second magnetic sensor, etc.) merely distinguish the respective components for clarity of description and are not intended to limit any order or to emphasize importance, etc. Further, the term "connected" used herein may be either directly connected or indirectly connected via other components without being particularly described.
The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A magnetic field concentrating assembly comprising at least two concentrically arranged magnetic field concentrators, said magnetic field concentrators being provided with longitudinal air gaps (3), a transverse air gap (4) being formed between two adjacent magnetic field concentrators, said transverse air gap (4) being adapted to receive a magnetic sensor.
2. A magnetic field concentration assembly according to claim 1, characterized in that the magnetic field concentration device comprises a first magnetic field concentration device (1) and a second magnetic field concentration device (2) arranged above the first magnetic field concentration device (1), that the first magnetic field concentration device (1) and the second magnetic field concentration device (2) are each provided with two longitudinal air gaps (3), that the two longitudinal air gaps (3) are arranged symmetrically with respect to the central axis of the magnetic field concentration device, and that a transverse air gap (4) is arranged between the first magnetic field concentration device (1) and the second magnetic field concentration device (2).
3. A magnetic field concentration assembly according to claim 1, characterized in that the magnetic field concentrator comprises a first magnetic field concentrator (1) and a second magnetic field concentrator (2) located outside the first magnetic field concentrator (1), that the first magnetic field concentrator (1) and the second magnetic field concentrator (2) are each provided with two longitudinal air gaps (3), that the two longitudinal air gaps (3) are arranged symmetrically with respect to the central axis of the magnetic field concentrator, and that a transverse air gap (4) is arranged between the first magnetic field concentrator (1) and the second magnetic field concentrator (2).
4. A magnetic field concentration assembly according to claim 2 or 3, characterized in that the longitudinal air gap (3) of the first magnetic field concentrator (1) is aligned with the longitudinal air gap (3) of the second magnetic field concentrator (2).
5. A magnetic field concentration assembly according to claim 2 or 3, wherein the width of the transverse air gap (4) is no greater than 5mm and the width of the longitudinal air gap (3) is no greater than 1 mm.
6. A non-contact leakage current measuring device comprises a housing (8), wherein a first magnetic field collector (1), a first magnetic sensor (5), a second magnetic sensor (6) and a signal processing circuit are arranged in the housing (8), the non-contact leakage current measuring device is characterized in that a second magnetic field collector (2) and a partition plate (9) are further arranged in the housing (8), the partition plate (9) is used for separating the first magnetic field collector (1) from the second magnetic field collector (2), the first magnetic field collector (1) and the second magnetic field collector (2) are concentrically arranged, two longitudinal air gaps (3) are respectively arranged on the first magnetic field collector (1) and the second magnetic field collector (2), a transverse air gap (4) is arranged between the first magnetic field collector (1) and the second magnetic field collector (2), and the first magnetic sensor (5), the second magnetic sensor (6) and the signal processing circuit are positioned in the transverse air gap (4), the first magnetic sensor (5) and the second magnetic sensor (6) are located between the longitudinal air gap (3) of the first magnetic field concentrator (1) and the longitudinal air gap (3) of the second magnetic field concentrator (2), and the first magnetic sensor (5) and the second magnetic sensor (6) are symmetrically arranged with respect to the central axis of the magnetic field concentrator; the first magnetic sensor (5) and the second magnetic sensor (6) are used for measuring the magnetic field in the transverse air gap (4) and outputting a voltage signal representing the magnetic field, and the signal processing circuit is used for receiving the voltage signal, processing the voltage signal and outputting a measuring result.
7. The noncontact leakage current measuring device of claim 6, wherein the signal processing circuit receives the voltage signals output by the first magnetic sensor (5) and the second magnetic sensor (6), and the voltage signals are processed by signal following, signal superposition, differential amplification and filtering to output the measurement result.
8. The non-contact leakage current measuring device of claim 7, wherein the signal superposition operation step specifically comprises: for the differential voltage signal V output by the first magnetic sensor (5)1+And V1-The second magnetic sensor (6) outputs a differential voltage signal and V2+And V2-Will V1+And V2+Adding to obtain a high-end potential V+，V1-And V2-Adding to obtain a low-end potential V-Then, the high-end potential V is set+And a low-side potential V-Are added to obtain a voltage signal V.
9. A non-contact leakage current measuring device according to any one of claims 6-8, wherein a temperature sensor (7) is further disposed in the housing (8), and the temperature sensor (7) is used for detecting the operating temperature of the first magnetic sensor (5) and/or the second magnetic sensor (6) and sending the temperature data to a signal processing circuit, and the signal processing circuit performs temperature compensation on the voltage signals output by the first magnetic sensor (5) and the second magnetic sensor (6).
10. A measuring method based on the non-contact leakage current measuring device of any one of claims 6 to 9, characterized by comprising the following steps:
the method comprises the following steps: fixedly mounting the non-contact leakage current measuring device outside a steel column (10) to be measured;
step two: the first magnetic sensor (5) outputs a differential voltage signal V to the signal processing circuit1+And V1-The second magnetic sensor (6) outputs a differential voltage signal V to the signal processing circuit2+And V2-；
Step three: the signal processing circuit converts V1+And V2+Adding to obtain a high-end potential V+Will V1-And V2-Adding to obtain a low-end potential V-And high end potential V is adjusted+And a low-side potential V-Adding to obtain a voltage signal V;
step four: and carrying out differential amplification and filtering processing on the voltage signal V and then outputting a measurement result.
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| CN201910958850.5A CN110672902A (en) | 2019-10-10 | 2019-10-10 | Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method |
| CN202011073802.7A CN111983280B (en) | 2019-10-10 | 2020-10-09 | Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method |
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| CN111579851A (en) * | 2020-05-08 | 2020-08-25 | 国网电力科学研究院武汉南瑞有限责任公司 | Buffer layer ablation current live detection system and method based on magnetic field effect |
| CN111983280A (en) * | 2019-10-10 | 2020-11-24 | 国网四川省电力公司电力科学研究院 | Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method |
| CN112327202A (en) * | 2020-07-07 | 2021-02-05 | 长沙理工大学 | Design method of non-invasive leakage detection sensor |
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| US8729889B2 (en) * | 2008-01-18 | 2014-05-20 | C-Sigma S.R.L. | Method and apparatus for magnetic contactless measurement of angular and linear positions |
| CN202661526U (en) * | 2012-01-19 | 2013-01-09 | 邹高芝 | Coaxial double-loop magnetic core coil assembly for core-through type high precision closed-loop type Hall current sensor |
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| CN103412176B (en) * | 2013-08-14 | 2016-01-20 | 清华大学 | Real-time on-line monitoring sensor for current of alternating current-direct current arrester based on magnetoresistance |
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| CN106093548B (en) * | 2016-08-04 | 2018-12-14 | 中国船舶重工集团公司第七一九研究所 | A kind of contactless high-precision shaft current measuring device |
| CN108306083B (en) * | 2018-02-01 | 2019-11-29 | 西南应用磁学研究所 | YIG resonance circuit integrated morphology |
| CN110095644A (en) * | 2019-04-10 | 2019-08-06 | 三峡大学 | A kind of novel high-precision open loop Hall current sensor |
| CN110672902A (en) * | 2019-10-10 | 2020-01-10 | 国网四川省电力公司电力科学研究院 | Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method |
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2019
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111983280A (en) * | 2019-10-10 | 2020-11-24 | 国网四川省电力公司电力科学研究院 | Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method |
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| CN111579851B (en) * | 2020-05-08 | 2022-04-22 | 国网电力科学研究院武汉南瑞有限责任公司 | Buffer layer ablation current live detection system and method based on magnetic field effect |
| CN112327202A (en) * | 2020-07-07 | 2021-02-05 | 长沙理工大学 | Design method of non-invasive leakage detection sensor |
| CN113625038A (en) * | 2021-06-23 | 2021-11-09 | 武汉钢铁有限公司 | Current measuring device and voltage and current measuring device |
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| CN111983280B (en) | 2023-03-03 |
| CN111983280A (en) | 2020-11-24 |
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Application publication date: 20200110 |
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