CN111983280B - 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
- Publication number
- CN111983280B CN111983280B CN202011073802.7A CN202011073802A CN111983280B CN 111983280 B CN111983280 B CN 111983280B CN 202011073802 A CN202011073802 A CN 202011073802A CN 111983280 B CN111983280 B CN 111983280B
- Authority
- CN
- China
- Prior art keywords
- magnetic field
- magnetic
- air gap
- sensor
- 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.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- 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
-
- 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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Measuring Magnetic Variables (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
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 power equipment is met.
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 developed greatly, so that the application range and the field of the power equipment online monitoring technology 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 multiple insulation performance related index parameters such as insulation resistance and relative dielectric loss values requires 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. The most common way for measuring the leakage current of the power equipment on line in the past 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, many problems have been exposed 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 grounding loop do not need to be 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 strength 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 leakage current of power equipment to the ground 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 known effectively. The measuring device comprises a first magnetic gathering ring and a second magnetic gathering ring which are semicircular, 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 utilizing 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 application of patent CN106093548A is that magnetic poly-ring structure is commonly used at present, and the structure 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 gaps, 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 conducive to increasing the signal-to-noise ratio in 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 the leakage current of the power equipment to the ground with the effective value of only a few milliamperes to a hundred 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 superposition of the edges of the upper longitudinal air gap, the lower longitudinal air gap or the inner longitudinal air gap and the outer longitudinal air gap is utilized to obviously improve the strength of a measured magnetic field, and 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, so that the strength of the measured 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 collectors, wherein longitudinal air gaps are arranged on the magnetic field collectors, and transverse air gaps are formed between two adjacent magnetic field collectors and are used for placing magnetic sensors.
The magnetic field gathering assembly in the technical scheme comprises at least two magnetic field gatherers, each magnetic field gatherer is of an existing annular structure, and a longitudinal air gap is formed in each magnetic field gatherer, namely the air gap on a single magnetic gathering ring in the prior art. Conventional magnetic field sensors are placed in the longitudinal air gap to measure the magnetic field generated by the current, due to the greater and more uniform magnetic field strength in the longitudinal air gap. 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 the longitudinal air gap, so that if the longitudinal air gap width is further reduced, a thinner magnetic field sensor with high cost is required, the production cost of the measuring device is undoubtedly increased, and the problem that the longitudinal air gap width is limited by the size of the magnetic field sensor is not fundamentally solved by the method.
In order to solve the above problems, the inventor has found through a large number of experiments and simulation simulations 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, an annular transverse air gap is formed between two adjacent magnetic field collectors along the circumferential direction of the magnetic field collectors, and the transverse air gap is used for placing the magnetic sensor therein.
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 leakage magnetic fields.
As a preferable structure of the present invention, the longitudinal air gaps of two adjacent magnetic sensors provided with the transverse air gaps of the magnetic sensors are aligned. As shown in FIG. 1, the magnetic field sensor is located between the longitudinal air gaps of the two magnetic field collectors, and 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 located 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 remarkably 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 width of the longitudinal air gap of the magnetic field collector 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, the leakage current with the effective value of only several milliamperes to hundreds milliamperes can be measured, and the precision requirement of measuring the ground leakage current of the power equipment 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 concentrator assembly of the present invention preferably employs two concentrically arranged magnetic field concentrators.
In 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 are symmetrically arranged on the first magnetic field collector relative to the central axis of the first magnetic field collector, and two longitudinal air gaps are symmetrically arranged on the second magnetic field collector relative 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 with respect to 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 present 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 inner diameter of the second magnetic field concentrator is larger than the outer diameter of the first magnetic field concentrator. Similar to the top and bottom 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 disposed about an axial line of the first magnetic field collector, and the second magnetic field collector is provided with two longitudinal air gaps symmetrically disposed about an axial line 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 with respect to 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 1mm. Preferably, the width of the transverse air gap can be controlled within 2-3 mm, and the transverse air gap is enough to be placed into the thickness of 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, as in the prior art, a housing in which a first magnetic field concentrator, a first magnetic sensor, a second magnetic sensor and a signal processing circuit are arranged.
Different from the prior art, the magnetic field gathering assembly of the measuring device is composed of two magnetic field gathers, 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 disposed in the housing, the partition plate is used for separating the first magnetic field collector from the second magnetic field collector, the first magnetic field collector and the second magnetic field collector are concentrically disposed, two longitudinal air gaps are disposed on the first magnetic field collector and the second magnetic field collector, a transverse air gap is disposed 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 located in the transverse air gap, the first magnetic sensor and the second magnetic sensor are located 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 disposed 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 shell 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 shell also provides protection for components such as a magnetic field sensor, a magnetic field collector, a signal processing circuit and the like in the shell, so that the long-term stable operation of the first magnetic field collector and the second magnetic field collector is ensured. Inside the housing a partition is arranged for separating 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; in the case of the first and second magnetic field collectors being arranged inside and outside, the partition is arranged vertically inside the housing, dividing the housing into an inner part and an outer part for accommodating the first and second magnetic field collectors, respectively. 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 semi-circular ring casings, and half first magnetic field collector and half second magnetic field collector are all equipped with in each semi-circular ring casing, and when two casings joint on the steel column, the shell surface was sealed, formed 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, mounting frames are arranged on the two shells, and fastening bolts penetrate through screw holes in the mounting frames of the two shells to achieve fastening.
The first magnetic sensor and the second magnetic sensor are respectively positioned in two centrosymmetric four-air-gap structures, and the first magnetic sensor and the second magnetic sensor obtain stronger magnetic induction intensity under weak current by measuring superimposed fringe magnetic fields of an upper longitudinal air gap, a lower longitudinal air gap or an inner longitudinal air gap and an outer longitudinal air gap, 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 in the prior art to 1000-1200mGs, and the signal-to-noise ratio and the sensitivity of the magnetic sensor are obviously improved. Moreover, the significantly improved magnetic induction makes the non-contact leakage current measuring device provided by the invention no longer need to design a setting/resetting circuit to reset the magnetic domain inside the sensor as in the signal circuit processing board of patent CN106093548A, thereby improving the sensitivity, effectively simplifying the design and processing steps of the signal processing circuit, reducing the production cost and improving the signal processing efficiency, and having 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 method is shown in fig. 7. Two output ports of the first magnetic sensor output differential voltage signals V respectively 1+ And V 1- Two output ports of the second magnetic sensor output differential voltage signals V respectively 2+ And V 2- . Wherein:
V 1+ ＝V B /2+V 1I /2+V D /2
V 1- ＝V B /2-V 1I /2-V D /2
V 2+ ＝V B /2+V 2I /2+(-V D /2)
V 2- ＝V B /2-V 2I /2-(-V D /2)
in the above formula, V B Bridge voltage, V, of the first/second magnetic sensors D The output V of the first magnetic sensor measures the output voltage signal for the geomagnetic field and the interference magnetic field 1+ 、V 1- Potential of V B A pair of differential signals with vertically symmetrical potential, V 1I The output V of the second magnetic sensor is measured for the measured current corresponding to the output voltage signal of the first magnetic sensor 2+ 、V 2- Potential is V B A pair of differential signals with vertically symmetrical potential, V 2I An 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 signal and output the common mode signal, namely two input potentials V 1+ 、V 1- (V 2+ 、V 2- ) Subtracting to obtain:
V 1 ＝V 1I +V D
V 2 ＝V 2I -V D
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＝V 1 +V 2 ＝V 1I +V 2I
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 the weak current signal is amplified by 40 times to 1V to meet the processing requirement of a later stage circuit, and the earth magnetic field signal is also amplified by 40 times to 20V in theory, so that the power supply of the amplifier is required to be set to be in theory
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 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 to 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 sampling value signal synchronized by a clock after being accessed with the clock synchronization signal, 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 sensor 1+ And V 1- The second magnetic sensor outputs a differential voltage signal sum V 2+ And V 2- Will V 1+ And V 2+ Adding to obtain a high-end potential V + ，V 1- And V 2- 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, wherein 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
V + ＝V 1+ +V 2+ ＝V B +V 1I /2+V 2I /2
V - ＝V 1- +V 2- ＝V B -V 1I /2-V 2I /2
Before the differential circuit is input, the high end and the low end of the magnetic sensor are butt-jointed for input, the high end potential and the low end potential of the earth magnetic field and the interference signal are respectively offset, and when the differential circuit is input, any component of the earth magnetic field signal is not existed, and only the earth magnetic field signal is superposedSize V B The 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 - ＝V 1I +V 2I
it can be seen that due to the input signal V + And V - The power supply does not contain a geomagnetic field and an interference magnetic field component, and 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. Moreover, because the high end and the low end are respectively butted, the geomagnetic field and the interference component are automatically eliminated, the differential acquisition of the sensor signals can be realized by only one differential amplifier in the whole circuit, compared with the circuit design which needs two differential amplifiers and one addition amplifier in the traditional mode, the cost is saved, the circuit structure is simplified, and the links which possibly introduce errors are reduced.
Further, still be provided with temperature sensor in the shell, temperature sensor is used for detecting the operating temperature of first magnetic sensor and/or second magnetic sensor to send temperature data to signal processing circuit, signal processing circuit carries out temperature compensation to the voltage signal of first magnetic sensor and second magnetic sensor output. 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:
U x25 ＝U x +a(T-25) 2 +b(T-25)
wherein, U x25 To calibrate the output signal of the first/second magnetic sensor at temperature, U x For the original output signal value (V) of the first/second magnetic sensor 1+ ,V 1- ,V 2+ ,V 2- ) 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 magnetic sensor and the second magnetic sensor, and are determined by the properties of the first magnetic sensor and the second magnetic sensor.
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 sensitivity corresponding to 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.
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 circuit 1+ And V 1- The second magnetic sensor outputs a differential voltage signal V to the signal processing circuit 2+ And V 2- ；
Step three: the signal processing circuit converts V 1+ And V 2+ Adding to obtain a high-end potential V + A V is measured 1- And V 2- 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 electric 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 earth magnetic field and interference magnetic field components which are possibly generated in the design of a circuit power supply 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 that of the traditional single air gap structure, the signal-to-noise ratio is improved, the leakage current with the effective value of only a few milliamperes to hundreds milliamperes can be measured, and the precision requirement of the ground leakage current measurement of power equipment is met;
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 positions 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 field 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, reduces the links which can introduce errors and inputs the signal V + And V - Free of geomagnetic and disturbing magnetic field components, from rootThe problem of the saturation of the amplifying circuit caused by overlarge geomagnetic field and interference magnetic field components which are possibly generated during the design of a circuit power supply is 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 at the calibration 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 figures:
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 meant to limit 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 or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore, should not be taken as limiting the scope of the invention.
Example 1:
the magnetic field concentrator assembly as shown in FIG. 2 comprises a first magnetic field concentrator 1 and a second magnetic field concentrator 2 disposed 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 disposed about a central axis of the magnetic field concentrator, and a transverse air gap 4 is disposed 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 fig. 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 collectors, 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 significantly improved by the superposition of 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 field sensor is calculated by the section of a magnetic field concentrator with the diameter of 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 collectors with 15mm multiplied by 15mm cross sections (2 groups of 15mm multiplied by 15mm have the same cross section volume with the traditional 30mm multiplied by 15 mm) form the four-air-gap structure, because the magnetic fields of the upper and lower groups of magnetic field collectors are superposed, the magnetic induction intensity at the intersection of a transverse air gap and a longitudinal air gap, namely the position where the 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 structure.
Because the 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 air gap magnetic induction intensity 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 that 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 ground leakage current measurement 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 1mm.
In some embodiments, the measuring direction of the magnetic field sensor is arranged parallel to the direction of the measured magnetic field to further increase 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 may be 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 1mm.
In some embodiments, the measuring direction of the magnetic field sensor is arranged parallel to the direction of the measured magnetic field to further increase 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 may be 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 about the central axis of the magnetic field collectors; 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 adopt the upper and lower placing mode 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, i.e. 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, as shown in fig. 5, the shell comprises two symmetrical semi-circular ring shells, a half of the first magnetic field collector and a half of the second magnetic field collector are arranged in each semi-circular ring shell, when the two shells 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:
in addition to the above embodiments, 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, 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 5 1+ And V 1- The second magnetic sensor 6 outputs the differential voltage signal and V 2+ And V 2- Will V 1+ And V 2+ Adding to obtain a high-end potential V + ，V 1- And V 2- 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 generated + And V - The power supply does not contain a geomagnetic field and an interference magnetic field component, and 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. 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 the differential acquisition of the sensor signal by only one differential amplifier, compared with the circuit design that two differential amplifiers and one addition amplifier are needed in the traditional mode, the cost is saved, the circuit structure is simplified, and the links that errors are possibly introduced are reduced.
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 to 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 analog quantity of the sensor 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 sampling value signal synchronized by a clock after being accessed with the clock synchronization signal, 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:
U x25 ＝U x +a(T-25) 2 +b(T-25)
wherein, U x25 To calibrate the output signal of the first/second magnetic sensor at temperature, U x For the original output signal value (V) of the first/second magnetic sensor 1+ ,V 1- ,V 2+ ,V 2- ) 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 magnetic sensor and the second magnetic sensor, and are determined by the properties of the first magnetic sensor and the second magnetic sensor.
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 sensitivity corresponding to 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.
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 circuit 1+ And V 1- The second magnetic sensor 6 outputs a differential voltage signal V to the signal processing circuit 2+ And V 2- ；
Step three: the signal processing circuit converts V 1+ And V 2+ Adding to obtain a high-end potential V + A V is measured 1- And V 2- Adding to obtain a low-end potential V - And high end potential V is adjusted + And low-end 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 electric 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 in 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 examples 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 concentration assembly is characterized by comprising at least two concentrically arranged magnetic field concentrators, wherein longitudinal air gaps (3) are arranged on the magnetic field concentrators, a transverse air gap (4) is formed between every two adjacent magnetic field concentrators, a magnetic sensor is placed in the transverse air gap (4), and the magnetic sensor is located right at the intersection of the transverse air gap (4) and the longitudinal air gap (3).
2. 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) arranged above 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).
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 1mm.
6. A non-contact leakage current measuring device, comprising 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), 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) and 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 central axis 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 second magnetic field collector (2), and the second magnetic sensor (5) and the magnetic sensor (6) are symmetrically arranged with respect to the longitudinal air gap (3); 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 V 1- The second magnetic sensor (6) outputs a differential voltage signal and V 2+ And V 2- A V is measured 1+ And V 2+ Adding to obtain a high-end potential V + ，V 1- And V 2- Adding to obtain low-end potential V - Then, the high-end potential V is set + And low-end 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 arranged in the housing (8), 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 is used for carrying out 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 according to any one of claims 6 to 9, comprising the steps of:
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 circuit 1+ And V 1- The second magnetic sensor (6) outputs a differential voltage signal V to the signal processing circuit 2+ And V 2- ；
Step three: the signal processing circuit converts V 1+ And V 2+ Adding to obtain a high-end potential V + Will V 1- And V 2- Adding to obtain 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.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2019109588505 | 2019-10-10 | ||
| CN201910958850.5A CN110672902A (en) | 2019-10-10 | 2019-10-10 | Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111983280A CN111983280A (en) | 2020-11-24 |
| CN111983280B true CN111983280B (en) | 2023-03-03 |
Family
ID=69081538
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910958850.5A Withdrawn CN110672902A (en) | 2019-10-10 | 2019-10-10 | Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method |
| CN202011073802.7A Active CN111983280B (en) | 2019-10-10 | 2020-10-09 | Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910958850.5A Withdrawn CN110672902A (en) | 2019-10-10 | 2019-10-10 | Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method |
Country Status (1)
| Country | Link |
|---|---|
| CN (2) | CN110672902A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| 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 |
| CN114779123B (en) * | 2022-06-22 | 2022-09-02 | 沈阳工业大学 | High tension transmission line leakage detector |
| CN117075009A (en) * | 2023-08-01 | 2023-11-17 | 江苏多维科技有限公司 | Magnetic field sensor and multiaxis magnetic field sensor |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103364612A (en) * | 2013-07-05 | 2013-10-23 | 华中科技大学 | Dual-Hall element current sensor |
| CN103412176A (en) * | 2013-08-14 | 2013-11-27 | 清华大学 | Real-time and on-line AC/DC arrester current monitoring sensor based on magnetoresistance |
| CN104520721A (en) * | 2012-01-19 | 2015-04-15 | 邹高芝 | Coaxial dual-loop magnetic core coil component for high-precision cross-core closed-loop hall current sensor |
| CN205280656U (en) * | 2016-01-05 | 2016-06-01 | 徐州博联科技有限公司 | Wire rope damage detects and gathers magnetic ring structure |
| CN106093548A (en) * | 2016-08-04 | 2016-11-09 | 中国船舶重工集团公司第七〇九研究所 | A kind of contactless high accuracy shaft current measurement apparatus |
| CN108306083A (en) * | 2018-02-01 | 2018-07-20 | 西南应用磁学研究所 | YIG resonance circuit integrated morphologies |
| 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 |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
-
2019
- 2019-10-10 CN CN201910958850.5A patent/CN110672902A/en not_active Withdrawn
-
2020
- 2020-10-09 CN CN202011073802.7A patent/CN111983280B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104520721A (en) * | 2012-01-19 | 2015-04-15 | 邹高芝 | Coaxial dual-loop magnetic core coil component for high-precision cross-core closed-loop hall current sensor |
| CN103364612A (en) * | 2013-07-05 | 2013-10-23 | 华中科技大学 | Dual-Hall element current sensor |
| CN103412176A (en) * | 2013-08-14 | 2013-11-27 | 清华大学 | Real-time and on-line AC/DC arrester current monitoring sensor based on magnetoresistance |
| CN205280656U (en) * | 2016-01-05 | 2016-06-01 | 徐州博联科技有限公司 | Wire rope damage detects and gathers magnetic ring structure |
| CN106093548A (en) * | 2016-08-04 | 2016-11-09 | 中国船舶重工集团公司第七〇九研究所 | A kind of contactless high accuracy shaft current measurement apparatus |
| CN108306083A (en) * | 2018-02-01 | 2018-07-20 | 西南应用磁学研究所 | YIG resonance circuit integrated morphologies |
| 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110672902A (en) | 2020-01-10 |
| CN111983280A (en) | 2020-11-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111983280B (en) | Magnetic field gathering assembly, non-contact leakage current measuring device and measuring method | |
| EP2950109B1 (en) | Calibration methods for voltage sensing devices | |
| CN114200199B (en) | Non-contact voltage measuring device based on multi-stage plate differential probe | |
| CN110687347A (en) | Hall current sensor with temperature compensation and temperature compensation method thereof | |
| CN1668934A (en) | Electronic interface for use with dual electrode capacitance diaphragm gauges | |
| CN103245824A (en) | Non-contact D-dot voltage transformer and voltage detection self-correcting method thereof | |
| CN104836542A (en) | Pre-amplifier for measuring wind-tunnel balance signal and calibration measurement method | |
| CN111122948A (en) | Tunnel magnetic resistance and Rogowski coil combined totally-enclosed current testing device | |
| CN103682862B (en) | A kind of ring main unit cable connector | |
| CN106093511B (en) | High-precision electronic current transformer with iron core coil containing air gap | |
| CN108022824A (en) | High-precision ion energy analysis instrument | |
| CN211206616U (en) | Hall current sensor with temperature compensation | |
| CN110441591A (en) | A kind of improved electronic mutual inductor current acquisition method | |
| CN110196383A (en) | The method for carrying out ipsilateral high-tension apparatus Partial Discharge Detection using capacitive bottom shielding of bushing | |
| CN209296807U (en) | A kind of alterating and direct current flow sensor | |
| CN113917229A (en) | Power frequency interference elimination method for power frequency detection circuit | |
| CN106908860A (en) | A kind of Lightning Warning system | |
| CN110988629A (en) | Self-correcting ultrasonic wave partial discharge tester and correcting method | |
| CN218939592U (en) | Digital ionization chamber detector | |
| CN204539092U (en) | A kind of preamplifier for wind-tunnel balance signal measurement | |
| CN211979037U (en) | High-precision iron core grounding on-line monitoring device | |
| CN220541974U (en) | Strain and temperature acquisition device | |
| CN215641493U (en) | Induction type voltage pulse detector | |
| CN217156639U (en) | Radar power supply system zero sequence current sampling device | |
| CN108955933A (en) | A kind of measuring circuit and parameter selection method improving rail temperature measurement accuracy |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |