CN112904078A - Giant magnetoresistance effect-based reactor branch current monitoring system and method - Google Patents
Giant magnetoresistance effect-based reactor branch current monitoring system and method Download PDFInfo
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Abstract
The utility model provides a reactor branch current monitoring system and method based on giant magnetoresistance effect, which relates to the technical field of power transmission and transformation, and comprises a sensing module, an information processing module, a main control module and a wireless transmission module; the sensing module comprises a magnetic resistance current sensor provided with a giant magnetic resistance chip, the magnetic resistance current sensor is connected with an encapsulating outgoing line of the reactor, the output end of the sensing module is connected with the input end of the signal processing circuit, the output end of the signal processing circuit is connected with the input end of the main control module, and the output end of the main control module is connected with the input end of the wireless receiving module through the wireless communication module. The application provides install the magnetic resistance current sensor on the outgoing line of encapsulating the branch road, and the change of real-time supervision branch road current improves the measuring accuracy through edge calculation mode, through wireless communication mode with data transmission to wireless receiving module, and then realizes the interturn insulation state monitoring of reactor, has advantages such as easy operation, installation are convenient, the degree of accuracy height.
Description
Technical Field
The application relates to the technical field of power transmission and transformation, in particular to a system and a method for monitoring branch current of a reactor based on a giant magnetoresistance effect.
Background
The reactor is an inductive high-voltage electrical appliance used for limiting short-circuit current, reactive compensation and phase shift in an electric power system, and magnetic flux forms a loop through air. The dry-type air reactor has more packaging branches, is easily affected by insufficient production process, transportation abrasion, severe operation weather conditions or dirt erosion by rain, snow, moisture, bird feces and the like, has the problems of inter-turn insulation aging, turn number deviation or strand breakage and the like, and gradually develops into inter-turn insulation short circuit faults. When the faults exist, the magnetic field distribution in the reactor is uneven, the local current of the fault point is overlarge to cause temperature rise, and the reactor is burnt out after long-term operation.
At present, the fault on-line monitoring method for the dry-type air-core reactor mainly comprises the following methods of temperature monitoring, noise/partial discharge monitoring, magnetic field monitoring, loss measurement and the like: the temperature monitoring method comprises an infrared imaging temperature measurement technology and an embedded temperature sensor monitoring method, but the infrared imaging temperature measurement technology cannot acquire the internal temperature of the dry-type air reactor, the accuracy is insufficient, and the embedded temperature sensor is complex to install and high in cost; the noise partial discharge monitoring method utilizes vibration or partial discharge signals generated when interlayer short circuit occurs in the reactor, but the method is easily influenced by environmental factors in field application and has larger error; the magnetic field detection detects the change of magnetic flux after the reactor is in fault through the induction coil, so that the fault monitoring is realized, and the method has higher cost and more complex installation process; the loss measurement method has a complicated measurement process and large field measurement error.
Disclosure of Invention
The application provides a reactor branch current monitoring system and method based on a giant magnetoresistance effect, and aims to solve the problems that in the prior art, the installation process is complex and the measurement process is complex.
The technical scheme adopted by the application is as follows:
a reactor branch current monitoring system based on giant magnetoresistance effect comprises:
the system comprises a sensing module, an information processing module, a main control module and a wireless transmission module;
the sensing module comprises a magnetic resistance current sensor provided with a giant magnetic resistance chip, the magnetic resistance current sensor is connected with an encapsulated outlet wire of the reactor, and the sensing module is used for measuring the current of a reactor branch circuit, calculating to obtain voltage and outputting a voltage signal;
the output end of the sensing module is connected with the input end of a signal processing circuit, and the signal processing circuit is used for receiving the output voltage, amplifying and zeroing the output voltage and then sending the amplified output voltage to the main control module;
the output end of the signal processing circuit is connected with the input end of the main control module, and the main control module is used for carrying out digital processing and edge calculation on the output voltage to obtain a current effective value, compressing the current effective value and then sending the compressed current effective value to the wireless receiving module through the wireless communication module;
the output end of the main control module is connected with the input end of the wireless receiving module through the wireless communication module, and the wireless receiving module is used for receiving the compressed current effective value and displaying, analyzing and storing the current effective value.
Furthermore, an amplifying circuit of the signal processing circuit adopts a differential operational amplifier, the bandwidth of the differential operational amplifier is greater than 30MHz, and two output ends of the giant magnetoresistance chip are respectively connected with two input ends of the differential operational square.
The wireless communication device further comprises a power supply module, wherein the power supply module comprises a battery and a power supply management unit, and the battery is respectively connected with the sensing module, the signal processing circuit, the main control module and the wireless communication module;
the output end of the main control module is connected with the battery management unit.
Furthermore, the giant magnetoresistance chip is arranged at the opening of the open magnetic ring, the sensitive direction of the giant magnetoresistance chip is vertical to the cross section direction of the air gap of the open magnetic ring, and the free end of the encapsulation outlet wire penetrates through the open magnetic ring.
Furthermore, a protective shell is arranged outside the open magnetic ring, and the protective shell is made of polyhexamethylene adipamide.
Furthermore, the sensing module, the information processing module and the main control module are connected through a shielding coaxial cable in sequence.
A method for monitoring the current of a reactor branch circuit based on the giant magnetoresistance effect comprises the following steps:
collecting a current value of an encapsulated wire of the reactor;
calculating the current value to obtain output voltage;
discharging and zeroing the output voltage;
then carrying out digital processing and edge calculation to obtain a current value;
and compressing the current value, and displaying, analyzing and storing to obtain the insulation state of the reactor.
The technical scheme of the application has the following beneficial effects:
the application provides a reactor branch current monitoring system and method based on giant magnetoresistance effect, wherein the system comprises a sensing module, an information processing module, a main control module and a wireless transmission module; the sensing module comprises a magnetic resistance current sensor provided with a giant magnetic resistance chip, the magnetic resistance current sensor is connected with an encapsulating outgoing line of the reactor, the output end of the sensing module is connected with the input end of the signal processing circuit, the output end of the signal processing circuit is connected with the input end of the main control module, and the output end of the main control module is connected with the input end of the wireless receiving module through the wireless communication module. The application provides install the magnetic resistance current sensor on the outgoing line of encapsulating the branch road, and the change of real-time supervision branch road current improves the measuring accuracy through edge calculation mode, through wireless communication mode with data transmission to wireless receiving module, and then realizes the interturn insulation state monitoring of reactor, has advantages such as easy operation, installation are convenient, the degree of accuracy height.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic diagram of an architecture of a reactor branch current detection system based on a giant magnetoresistance effect according to the present application;
FIG. 2 is a flow chart of packed transmission of current valid value data;
FIG. 3 is a schematic view of the installation of a giant magnetoresistance chip and an open magnetic ring;
illustration of the drawings:
wherein, 1-opening magnetic ring, 2-giant magnetoresistance chip, and 3-packaging outlet.
Detailed Description
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following examples do not represent all embodiments consistent with the present application. But merely as exemplifications of systems and methods consistent with certain aspects of the application, as recited in the claims.
Referring to fig. 1, a schematic diagram of an architecture of a reactor branch current detection system based on a giant magnetoresistance effect is provided in the present application.
Generally, when the dry-type air-core reactor works normally, the coil structure is stable, and basic parameters of the reactor, such as inductance, mutual inductance and resistance value, are relatively fixed, so that the current of each encapsulated branch circuit under rated voltage is basically stable. When the dry-type air-core reactor has turn-to-turn faults, the distribution of the magnetic field in the reactor is uneven, the self-inductance and mutual inductance parameters of the branch circuits are changed, and the current of the branch circuits is obviously changed. That is, the state of turn-to-turn insulation can be directly reflected by monitoring the branch current of the reactor. Therefore, the application provides a system and a method for detecting the current of a reactor branch circuit based on the giant magnetoresistance effect.
The application provides a reactor branch current monitoring system based on giant magnetoresistance effect includes: the device comprises a sensing module, an information processing module, a main control module and a wireless transmission module.
The sensing module comprises a magnetic resistance current sensor provided with a giant magnetic resistance chip, and the giant magnetic resistance chip is used as a measuring module, so that the sensing module has the advantages of strong anti-interference capability, low power consumption, wide frequency band and the like. The reluctance current sensor is connected with an encapsulated outlet wire of the reactor, and the sensing module is used for measuring the current of a reactor branch circuit, calculating to obtain voltage and outputting a voltage signal.
The output end of the sensing module is connected with the input end of the signal processing circuit, and the signal processing circuit is used for receiving the output voltage, amplifying and zeroing the output voltage and then sending the amplified output voltage to the main control module.
In general, the output signal of the giant magnetoresistance chip includes a certain common mode voltage, which is not a useful signal, in addition to the differential mode voltage reflecting the magnitude of the current to be measured. The signal processing circuit is required not only to amplify the differential mode voltage in the output signal of the giant magnetoresistance chip but also to suppress the common mode voltage therein. Therefore, the instrumentation amplifier is selected as an amplifying circuit in the signal processing circuit, a differential operational amplifier AD8044 with the bandwidth larger than 30MHz is adopted, and the power supply reference chip adopts LM 7805. The input terminals VIN1 and VIN2 of the operational amplifier are respectively connected to two output terminals of the giant magnetoresistance chip.
The output end of the signal processing circuit is connected with the input end of the main control module through a shielded coaxial cable. The main control module selects an MSP430F4 chip, the working power supply is 1.8-3.6V, the standby power consumption is 0.9 muA, when the chip works under the 1MHz dominant frequency, the power consumption can be as low as 220 muA @2.2V, and 12-bit A/D is arranged in the MSP430F4 chip. The functions of the main control module include: and performing digital processing on the output voltage, namely performing encryption safety processing on the output voltage.
In order to reduce the power consumption of the magnetoresistive current sensor and reduce the data volume transmission as much as possible under the steady-state working condition, the main control module further comprises a function of realizing the edge calculation of the effective current value.
The main control module also comprises a control management communication unit which compresses the current effective value and then sends the current effective value to the wireless receiving module through the wireless communication module.
The output end of the main control module is connected with the input end of the wireless receiving module through the wireless communication module, and the wireless receiving module is used for receiving the compressed current numerical value and displaying, analyzing and storing the current numerical value.
The data sensed by the wireless communication module are current effective values, and the wireless communication distance is short, so that the wireless communication module selects an RF communication scheme with low power consumption and high transmission rate. After the main control module completes data processing, current effective value data obtained through monitoring needs to be integrated and packaged according to a self-defined protocol so as to meet the requirements of wireless communication, and the protocol of corresponding data is shown in table 1. The flow chart of the packed transmission of the current effective value data is shown in fig. 2. The MCU in FIG. 2 is a single chip microcomputer in the main control module.
TABLE 1 data protocol
The application provides a reactor branch current monitoring system based on giant magnetoresistance effect still includes power module, and power module includes battery and power management unit. The battery is respectively connected with the sensing module, the signal processing circuit, the main control module and the wireless communication module and provides energy support for the modules. The output end of the main control module is also connected with a battery management unit, and the battery management module is controlled by the main control module and receives the instruction of the main control module to provide required electric energy for other modules.
In addition, since the magnetoresistive current sensor measures current based on the magnetic field measurement principle, and is sensitive to current position, current angle, proximity current and environmental magnetic field, small changes in these factors may cause large measurement errors. Therefore, in practical applications, the magnetoresistive current sensor generally needs to be used together with an open magnetic ring so as to reduce the sensitivity to the position and angle of the current and play a role in shielding the current and magnetic field interference outside the magnetic ring. The open magnetic ring also has the function of gathering a magnetic field, and compared with the condition without the magnetic ring, the magnetic field at the air gap of the magnetic ring is obviously enhanced, so that the reluctance current sensor can measure smaller current. The magnetic field intensity at the air gap can be changed by changing the width of the air gap of the magnetic ring, so that the sensitivity of the magnetic current sensor is adjusted.
As shown in fig. 3, a schematic diagram of the installation of the giant magnetoresistance chip and the open magnetic ring is shown. The open magnetic ring 1 is made of ferrite materials, the inner diameter is 5.5mm, the outer diameter is 15mm, the air gap of the magnetic ring is 2mm, and the relative magnetic conductivity is more than 1000. The sensitive direction of the giant magnetoresistance chip 2 is vertical to the cross section direction of the air gap of the open magnetic ring 1. The free end of the packaging line 3 passes through the opening magnetic ring 1.
And the reluctance current sensor is installed on the outgoing line of the dry-type air-core reactor, and the equipment is in a high potential area. Therefore, insulation protection is required to be considered, and the shell material of the equipment needs to have better insulation performance. The sensor shell is directly connected with the external environment, is required to bear rain and sunshine, directly bears radiation of an electric field and a magnetic field, provides insulation protection for an internal circuit, and is required to analyze heating and insulation of power equipment to bear possible high temperature. Open fire may occur when a measuring point is in failure, and the protective shell material needs to have certain flame retardance. Polyhexamethylene adipamide is selected as a protective shell material of the magnetoresistive current sensor, so that the requirement on the insulating property can be met, and an internal circuit is protected.
The application also provides a reactor branch current monitoring method based on the giant magnetoresistance effect, which comprises the following steps:
collecting a current value of an encapsulated wire of the reactor;
calculating the current value to obtain output voltage;
discharging and zeroing the output voltage;
then carrying out digital processing and edge calculation to obtain a current value;
and (4) compressing the current value, displaying, analyzing and storing to obtain the insulation state of the reactor.
The sensing system of the application tests: the 2 magnetoresistive current sensors are installed on the outgoing line of the reactor encapsulating layer 14, the test directions are respectively horizontal and vertical, then the current magnitude is gradually adjusted, and the test results are shown in table 2.
TABLE 2 test results
As can be seen from Table 2, the test result is basically consistent with the theoretical current value, so that the giant magnetoresistance effect-based reactor branch current monitoring system and method can realize measurement of energy flow at the distribution point of the reactor. The change condition of obtaining reactor branch road current can be monitored through this application, and the change condition of branch road current can reflect the change condition of reactor insulating properties.
According to the reactor branch current monitoring system and method based on the giant magnetoresistance effect, the magnetoresistance current sensor is installed on an outgoing line of an encapsulated branch, the change of the reactor branch current is monitored in real time, the measurement accuracy is improved in an edge calculation mode, data are transmitted to the wireless receiving module in a wireless communication mode, then the inter-turn insulation state monitoring of the reactor is achieved, and the reactor branch current monitoring system and method have the advantages of being simple in operation, convenient to install, high in accuracy and the like.
The embodiments provided in the present application are only a few examples of the general concept of the present application, and do not limit the scope of the present application. Any other embodiments extended according to the scheme of the present application without inventive efforts will be within the scope of protection of the present application for a person skilled in the art.
Claims (7)
1. A reactor branch current monitoring system based on giant magnetoresistance effect is characterized by comprising:
the system comprises a sensing module, an information processing module, a main control module and a wireless transmission module;
the sensing module comprises a magnetic resistance current sensor provided with a giant magnetic resistance chip, the magnetic resistance current sensor is connected with an encapsulated outlet wire of the reactor, and the sensing module is used for measuring the current of a reactor branch circuit, calculating to obtain voltage and outputting a voltage signal;
the output end of the sensing module is connected with the input end of a signal processing circuit, and the signal processing circuit is used for receiving the output voltage, amplifying and zeroing the output voltage and then sending the amplified output voltage to the main control module;
the output end of the signal processing circuit is connected with the input end of the main control module, and the main control module is used for carrying out digital processing and edge calculation on the output voltage to obtain a current effective value, compressing the current effective value and then sending the compressed current effective value to the wireless receiving module through the wireless communication module;
the output end of the main control module is connected with the input end of the wireless receiving module through the wireless communication module, and the wireless receiving module is used for receiving the compressed current effective value and displaying, analyzing and storing the current effective value.
2. The reactor branch current monitoring system based on the giant magnetoresistance effect according to claim 1, wherein the amplifying circuit of the signal processing circuit adopts a differential operational amplifier, the bandwidth of the differential operational amplifier is greater than 30MHz, and two output ends of the giant magnetoresistance chip are respectively connected with two input ends of the differential operational method.
3. The reactor branch current monitoring system based on the giant magnetoresistance effect according to claim 1, further comprising a power supply module, wherein the power supply module comprises a battery and a power supply management unit, and the battery is respectively connected with the sensing module, the signal processing circuit, the main control module and the wireless communication module;
the output end of the main control module is connected with the battery management unit.
4. The reactor branch current monitoring system based on the giant magnetoresistance effect according to claim 1, wherein the giant magnetoresistance chip is disposed at an opening of the open magnetic ring, a sensitive direction of the giant magnetoresistance chip is perpendicular to a cross section direction of an air gap of the open magnetic ring, and a free end of the encapsulating wire passes through the open magnetic ring.
5. The reactor branch current monitoring system based on the giant magnetoresistance effect according to claim 1, wherein a protective casing is further arranged outside the open magnetic ring, and the protective casing is made of polyhexamethylene adipamide.
6. The giant magnetoresistance effect-based reactor branch current monitoring system according to claim 1, wherein the sensing module, the information processing module and the main control module are connected sequentially through a shielded coaxial cable.
7. A method for monitoring the current of a reactor branch circuit based on the giant magnetoresistance effect is characterized by comprising the following steps:
collecting a current value of an encapsulated wire of the reactor;
calculating the current value to obtain output voltage;
discharging and zeroing the output voltage;
then carrying out digital processing and edge calculation to obtain a current value;
and compressing the current value, and displaying, analyzing and storing to obtain the insulation state of the reactor.
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| CN115541984A (en) * | 2022-11-30 | 2022-12-30 | 中国电力科学研究院有限公司 | Self-adaptive weak current monitoring device and monitoring method |
| CN115986671A (en) * | 2023-03-20 | 2023-04-18 | 国网浙江省电力有限公司金华供电公司 | Enhanced energy aggregation controller with low-power consumption and broadband current sensing |
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