1. A low-voltage transformer area shunt monitoring device comprises an AC-DC switching power supply, a backup power supply, a DC-DC/LDO power supply, a service management core, a three-phase voltage sampling circuit and a three-phase current sampling circuit; the method is characterized in that: the device also comprises a voltage metering signal conditioning circuit, a current metering signal conditioning circuit and a metering chip HT7022E circuit or an SOC chip RN 2026;

the three-phase voltage sampling circuit and the three-phase current sampling circuit are respectively connected with the voltage metering signal conditioning circuit and the current metering signal conditioning circuit through PT and CT; the voltage metering signal conditioning circuit and the current metering signal conditioning circuit are both connected with the metering chip HT7022E circuit or the SOC chip RN2026, and the metering chip HT7022E circuit or the SOC chip RN2026 is also connected with the business management core.

2. The low-voltage pad shunt monitoring device of claim 1, wherein: after the three-phase voltage collected by the three-phase voltage sampling circuit and the three-phase current collected by the three-phase current sampling circuit respectively pass through PT and CT isolation, related alternate collection signals are sent to the voltage metering signal conditioning circuit and the current metering signal conditioning circuit for processing, the processed signals are sent to the metering chip HT7022E circuit or the SOC chip RN2026, the metering chip HT7022E circuit or the SOC chip RN2026 realizes basic metering and original ADC data are externally transmitted to the service management core through the DMA function of the SPI.

3. The low-voltage pad shunt monitoring device of claim 1, wherein: the circuit comprises a voltage metering signal conditioning circuit, a current metering signal conditioning circuit, a differential to single-ended operational amplifier circuit and a metering chip HT7022E circuit, wherein the voltage metering signal conditioning circuit and the current metering signal conditioning circuit are connected with the differential to single-ended operational amplifier circuit, and the differential to single-ended operational amplifier circuit is connected with the metering chip HT7022E circuit or the SOC chip RN2026 and the service management chip respectively.

4. The low-voltage land shunt monitoring device of claim 3, wherein: signals processed by the voltage measurement signal conditioning circuit and the current measurement signal conditioning circuit can be processed by the differential to single-ended operational amplifier circuit, and ADC data in the case of a fault can be transmitted to the service management core in real time.

5. The low-pressure pad shunt monitoring device of any one of claims 3-4, wherein: the differential-to-single-ended operational discharge circuit is composed of 4-channel operational amplifiers of the SGM8270, one SGM8270 completes the differential-to-single-ended conversion of 3 paths of voltage or 3 paths of current, and the remaining 1 path of operational amplifier can just be used as a voltage follower to supply power for direct-current configuration voltage.

6. A wave recording and fault studying and judging method of a low-voltage transformer area shunt monitoring device is characterized by comprising the following specific steps:

step1, powering on the system for initialization;

step2, when the ADC data generates DMA half-full and full interrupt, starting special SPI transmission in an interrupt service program, and transmitting the ADC data to a specified BUFF of the main control MCU; the master control MCU respectively carries out fault judgment and signal identification processing on the data;

and (3) fault judgment processing: firstly, carrying out normalization processing on ADC sampling data, calculating a real-time value of voltage and current in real time, and carrying out various fault judgments on the data; when a fault occurs, actively reporting and storing fault information, and simultaneously carrying out fault recording;

identification and judgment processing: firstly, carrying out legality analysis on ADC (analog to digital converter) sampling data, then carrying out FFT (fast Fourier transform), and carrying out identification analysis on the transformed data; if the characteristic signal is identified, storing the identification record and waiting for the record to be read; and finally, generating the whole topology by the terminal and the master station.

7. The method for researching and judging the wave recording and the fault of the low-voltage transformer area shunt monitoring device according to claim 1, wherein the method comprises the following steps: in Step1, the initialization includes ADC sampling data related initialization, ADC DMA and SPI DMA initialization, and DMA half-full and full interrupt initialization.

Background

The traditional low-voltage monitoring device is based on a special ADC chip, and related functions are constructed by adopting a complex peripheral analog circuit. In this architecture, the basic metering function and the station area monitoring function are separated. The method has the defects of high circuit complexity, high cost, more occupied space and the like. The defects do not meet the development trends of miniaturization, low cost, circuit intellectualization and the like of the existing low-voltage monitoring device.

Fig. 1 shows a conventional analog circuit scheme of a low-voltage distribution room shunt monitoring device, in which basic metering and distribution room monitoring functions belong to two separate branches. The metering chip can adopt the current mainstream HT7036 and the like, and belongs to a dual-core metering framework meeting the IR 46. The platform area monitoring function is realized by a data processing unit, external voltage and current signals are respectively subjected to PT and CT isolation sampling and then sent to a special signal conditioning circuit, then are subjected to filtering and amplification (including frequency-selective amplification) and then sent to a special ADC chip for further data processing, and then a service management chip reads the data of the ADC chip and performs data interaction with a main control platform, so that the platform area monitoring function is realized. In this scheme, two management chips exist, and the architecture is complex. The ADC chip that this scheme used is with higher costs, and whole platform district monitoring function treatment effect receives analog circuit effects influences such as front end filtering, frequency-selecting enlargies, in industrial grade service environment, receives outside EMC to disturb easily. The structure is complex for the main control platform, the cost is high, and the occupied space is large;

the disadvantages of the conventional solution are also as follows:

1. the architecture is complex. There are multiple management cores.

2. The cost is high. The platform area monitoring function and the basic metering function exist separately. The realization of the platform area monitoring function depends on a large number of analog circuits to realize signal conditioning, and the adopted ADC chip is often higher in cost.

3. The stability is poor. The dependence of the platform area monitoring function on the signal conditioning analog circuit is extremely high, and the conditions of poor effect and instability are easy to occur in a complex electromagnetic environment.

4. The occupied space is large, and the miniaturization installation is not facilitated. Due to the fact that the structure is complex, and a plurality of analog circuits are adopted to achieve the platform area monitoring function, the whole device needs to occupy more space, and the requirements of miniaturization, intellectualization, low cost and the like of a low-voltage monitoring terminal at present are not met.

5. High requirements on interfaces and is not beneficial to wide application. The metering management core and the service management core need to have interactive communication with the master control platform at the same time, and the requirement on the reserved interface of the master control platform is high, so that the metering management core and the service management core are not beneficial to being widely applied to the platform area monitoring device.

Disclosure of Invention

In order to solve the problems, the invention provides a low-voltage transformer area shunt monitoring device and a wave recording and fault studying and judging method thereof, wherein a high-precision metering chip HT7022E + a differential-to-single-end operational amplifier circuit or an SOC metering chip + a differential-to-single-end operational amplifier circuit is used, and ADC data is uploaded to an AD port of a service management core in real time through the operational amplifier circuit while basic metering is realized by the metering chip, so that a fault studying and judging function is realized.

The technical scheme of the invention is as follows: a low-voltage transformer area shunt monitoring device comprises an AC-DC switching power supply, a backup power supply, a DC-DC/LDO power supply, a service management core, a three-phase voltage sampling circuit, a three-phase current sampling circuit, a voltage metering signal conditioning circuit, a current metering signal conditioning circuit and a metering chip HT7022E circuit or an SOC chip RN 2026;

the three-phase voltage sampling circuit and the three-phase current sampling circuit are respectively connected with the voltage metering signal conditioning circuit and the current metering signal conditioning circuit through PT and CT; the voltage metering signal conditioning circuit and the current metering signal conditioning circuit are both connected with the metering chip HT7022E circuit or the SOC chip RN2026, and the metering chip HT7022E circuit or the SOC chip RN2026 is also connected with the business management core.

As a further scheme of the present invention, after the three-phase voltage collected by the three-phase voltage sampling circuit and the three-phase current collected by the three-phase current sampling circuit, including the zero-sequence current, are isolated by PT and CT, the related signals are sent to the voltage measurement signal conditioning circuit and the current measurement signal conditioning circuit for processing, the processed signals are sent to the measurement chip HT7022E circuit or the SOC chip RN2026, the measurement chip HT7022E circuit or the SOC chip RN2026 realizes the basic measurement, and the original ADC data is externally transmitted to the service management core through the SPI DMA function.

As a further scheme of the invention, the differential-to-single-ended operational amplifier circuit further comprises a differential-to-single-ended operational amplifier circuit, wherein the voltage measurement signal conditioning circuit and the current measurement signal conditioning circuit are both connected with the differential-to-single-ended operational amplifier circuit, and the differential-to-single-ended operational amplifier circuit is respectively connected with the measurement chip HT7022E circuit or the SOC chip RN2026 and the service management core.

As a further scheme of the present invention, the signals processed by the voltage measurement signal conditioning circuit and the current measurement signal conditioning circuit can be processed by the differential to single-ended operational amplifier circuit, and then ADC data when a fault occurs is transmitted to the service management core in real time.

As a further scheme of the present invention, the differential-to-single-ended operational discharge circuit is composed of 4-channel operational amplifiers of the SGMs 8270, one SGM8270 completes the differential-to-single-ended conversion of 3-channel voltage or 3-channel current, and the remaining 1-channel operational amplifier can be just used as a voltage follower to supply power to the dc configuration voltage.

A wave recording and fault studying and judging method of a low-voltage transformer area shunt monitoring device comprises the following specific steps:

step1, powering on the system for initialization;

step2, when the ADC data generates DMA half-full and full interrupt, starting special SPI transmission in an interrupt service program, and transmitting the ADC data to a specified BUFF of the main control MCU; the master control MCU respectively carries out fault judgment and signal identification processing on the data;

and (3) fault judgment processing: firstly, carrying out normalization processing on ADC sampling data, calculating a real-time value of voltage and current in real time, and carrying out various fault judgments on the data; when a fault occurs, actively reporting and storing fault information, and simultaneously carrying out fault recording;

identification and judgment processing: firstly, carrying out legality analysis on ADC (analog to digital converter) sampling data, then carrying out FFT (fast Fourier transform), and carrying out identification analysis on the transformed data; if the characteristic signal is identified, storing the identification record and waiting for the record to be read; and finally, generating the whole topology by the terminal and the master station.

As a further scheme of the present invention, in Step1, the initialization includes ADC sampling data related initialization, ADC DMA initialization, SPI DMA initialization, and DMA half-full and full interrupt initialization.

The invention is applied to a high-precision special metering chip HT7022E (other metering chips with the same function can also be used), and realizes the real-time data transmission function of the ADC and the fusion of basic metering and area fault monitoring functions by utilizing a differential-to-single-ended operational amplifier circuit.

The invention cancels the middle chip in the data processing unit of the traditional scheme, changes a high-precision special metering chip HT7022E circuit and a differential-to-single-end operational amplifier circuit into the data processing unit, and transmits ADC data when a fault occurs to a service management core in real time through the differential-to-single-end operational amplifier circuit. The single alternate mining metering function in the traditional scheme is changed into the alternate mining and fault studying and judging dual realization, so that a special intermediate chip with higher cost can be cancelled, a real-time fault studying and judging function is added, meanwhile, the requirement on a service management core is further reduced, the whole framework is simpler, and the cost is reduced to a greater extent. The scheme of the invention fully utilizes the integrated circuit and reduces the requirement on space occupation. The low-voltage transformer area monitoring device applying the new scheme has the advantages of being strong in stability, high in intelligence and the like, meanwhile, the requirement for the main control interface is further reduced, only one SPI or USB is arranged on the main control interface, and the business management core can reserve the basic metering function in a transparent transmission mode.

The invention has the beneficial effects that:

1. the cost is low. The advantages of the large-scale integrated circuit are fully utilized, the use of a special intermediate management chip is cancelled, and the model selection requirement of the service management chip is reduced.

2. The reliability is high. Based on the use of a special high-precision metering chip, the electromagnetic environment influence caused by a peripheral analog circuit does not exist any more, and the high-precision metering chip has high reliability.

3. The intellectualization is high. The software algorithm replaces a signal conditioning circuit consisting of analog components, has high configurability and strong maintainability, and is convenient for upgrading and processing.

4. The universality is strong. The requirement on the main control interface is low, and the method is suitable for being applied to low-voltage monitoring devices on a large scale.

5. The miniaturization degree is high. The simplified circuit design reduces the space requirement and is convenient for the miniaturization of the low-voltage monitoring device.

6. The low-voltage shunt monitoring device described in the invention can realize the fusion of basic metering and area fault monitoring functions. The method can monitor and collect massive original alternate collection data in real time, and analyze and process the data;

7. the low-voltage shunt monitoring device described in the invention cancels a complex intermediate management chip, changes a special metering chip and operational amplifier circuit mode into the mode, and fully utilizes a mature large-scale integrated circuit to realize the construction of a related functional circuit. A large number of functions realized by the original analog circuit are realized by software algorithm, and the method has the advantages of low cost, small occupied space, high intelligence and the like. In addition, the invention also provides a typical fault studying and judging method of the low-voltage distribution area by combining the principle of the low-voltage shunt monitoring device aiming at the fault characteristics of the low-voltage distribution area.

Drawings

FIG. 1 is a schematic structural diagram of a conventional low-voltage distribution room shunt monitoring device;

FIG. 2 is a schematic structural diagram of a low-voltage transformer area shunt monitoring device according to the present invention;

FIG. 3 is a flow chart of a method for recording and determining faults according to the present invention;

FIG. 4 is a schematic diagram of an A-phase voltage signal sampling and conditioning circuit of the present invention;

FIG. 5 is a schematic diagram of a phase A current signal sampling and conditioning circuit of the present invention;

FIG. 6 is a schematic circuit diagram of a metering chip HT7022E according to the present invention;

FIG. 7 is a schematic diagram of a current interleaving circuit according to the present invention;

fig. 8 and 9 are schematic diagrams of the operational amplifier circuit of the present invention.

Detailed Description

Example 1: as shown in fig. 1-3, a low-voltage transformer area shunt monitoring device includes an AC-DC switching power supply, a backup power supply, a DC-DC/LDO power supply, a service management core, a three-phase voltage sampling circuit, a three-phase current sampling circuit, a voltage measurement signal conditioning circuit, a current measurement signal conditioning circuit, and a measurement chip HT7022E circuit; the three-phase voltage sampling circuit and the three-phase current sampling circuit are respectively connected with the voltage metering signal conditioning circuit and the current metering signal conditioning circuit through PT and CT; the voltage measurement signal conditioning circuit and the current measurement signal conditioning circuit are both connected with the measurement chip HT7022E, and the measurement chip HT7022E is also connected with the service management core. After the three-phase voltage collected by the three-phase voltage sampling circuit and the three-phase current collected by the three-phase current sampling circuit respectively pass through PT and CT isolation, related alternate collection signals are sent to the voltage metering signal conditioning circuit and the current metering signal conditioning circuit for processing, the processed signals are sent to the metering chip HT7022E circuit, and the metering chip HT7022E circuit realizes basic metering and transmits original ADC data to the service management core through the DMA function of SPI.

A wave recording and fault studying and judging method of a low-voltage transformer area shunt monitoring device comprises the following specific steps:

step1, powering on the system for initialization; the initialization comprises ADC sampling data related initialization, ADC DMA and SPI DMA initialization, and DMA half-full and full interrupt initialization;

step2, when the ADC data generates DMA half-full and full interrupt, starting special SPI transmission in an interrupt service program, and transmitting the ADC data to a specified BUFF of the main control MCU; the master control MCU respectively carries out fault judgment and signal identification processing on the data;

and (3) fault judgment processing: firstly, carrying out normalization processing on ADC sampling data, calculating a real-time value of voltage and current in real time, and carrying out various fault judgments on the data; when a fault occurs, actively reporting and storing fault information, and simultaneously carrying out fault recording;

identification and judgment processing: firstly, carrying out legality analysis on ADC (analog to digital converter) sampling data, then carrying out FFT (fast Fourier transform), and carrying out identification analysis on the transformed data; if the characteristic signal is identified, storing the identification record and waiting for the record to be read; and finally, generating the whole topology by the terminal and the master station.

Example 2: as shown in fig. 1-4 and 6, a low-voltage transformer area shunt monitoring device includes an AC-DC switching power supply, a backup power supply, a DC-DC/LDO power supply, a service management core, a three-phase voltage sampling circuit, a three-phase current sampling circuit, a voltage measurement signal conditioning circuit, a current measurement signal conditioning circuit, a measurement chip HT7022E circuit, and a differential-to-single-ended operational amplifier circuit; the three-phase voltage sampling circuit and the three-phase current sampling circuit are respectively connected with the voltage metering signal conditioning circuit and the current metering signal conditioning circuit through PT and CT; the voltage measurement signal conditioning circuit and the current measurement signal conditioning circuit are both connected with the measurement chip HT7022E, and the measurement chip HT7022E is also connected with the service management core. After the three-phase voltage collected by the three-phase voltage sampling circuit and the three-phase current collected by the three-phase current sampling circuit respectively pass through PT and CT isolation, related alternate collection signals are sent to the voltage metering signal conditioning circuit and the current metering signal conditioning circuit for processing, the processed signals are sent to the metering chip HT7022E circuit, and the metering chip HT7022E circuit realizes basic metering and transmits original ADC data to the service management core through the DMA function of SPI. The voltage measurement signal conditioning circuit and the current measurement signal conditioning circuit are both connected with the differential-to-single-ended operational amplifier circuit, and the differential-to-single-ended operational amplifier circuit is respectively connected with the measurement chip HT7022E circuit and the service management core.

The differential-to-single-ended operational discharge circuit is composed of 4-channel operational amplifiers of the SGM8270, one SGM8270 completes the differential-to-single-ended conversion of 3 paths of voltage or 3 paths of current, and the remaining 1 path of operational amplifier can just be used as a voltage follower to supply power for direct-current configuration voltage.

A wave recording and fault studying and judging method of a low-voltage transformer area shunt monitoring device comprises the following specific steps:

step1, powering on the system for initialization; the initialization comprises ADC sampling data related initialization, ADC DMA and SPI DMA initialization, and DMA half-full and full interrupt initialization;

step2, when the ADC data generates DMA half-full and full interrupt, starting special SPI transmission in an interrupt service program, and transmitting the ADC data to a specified BUFF of the main control MCU; the master control MCU respectively carries out fault judgment and signal identification processing on the data;

and (3) fault judgment processing: firstly, carrying out normalization processing on ADC sampling data, calculating a real-time value of voltage and current in real time, and carrying out various fault judgments on the data; when a fault occurs, actively reporting and storing fault information, and simultaneously carrying out fault recording;

identification and judgment processing: firstly, carrying out legality analysis on ADC (analog to digital converter) sampling data, then carrying out FFT (fast Fourier transform), and carrying out identification analysis on the transformed data; if the characteristic signal is identified, storing the identification record and waiting for the record to be read; and finally, generating the whole topology by the terminal and the master station.

FIG. 6 is a schematic diagram of a circuit of a metering chip HT7022E used in the present invention;

the working principle of the invention is briefly described as follows: after the three-phase voltage and the three-phase current (including zero sequence current) are respectively isolated by a PT (voltage transformer) and a CT (current transformer), related alternate acquisition signals are sent to a metering signal conditioning circuit. The circuit is a spy shadow filter circuit which is mature in application, processed metering signals are sent into a voltage and current phase ADC corresponding to a metering chip HT7022E circuit, the metering chip HT7022E circuit can achieve a basic metering function, and original ADC data can be transmitted to a business management core through a DMA function of a special SPI. The basic metering function can carry out data interaction through the SPI in butt joint with the main control board.

Example 3: as shown in fig. 1 to 5 and fig. 7 to 9, the present embodiment is the same as embodiment 2, except that the circuit of the metering chip HT7022E in embodiment 2 is replaced with an SOC chip RN 2026;

the working principle of the invention is briefly described as follows: after the three-phase voltage and the three-phase current (including zero sequence current) are respectively isolated by a PT (voltage transformer) and a CT (current transformer), related alternate acquisition signals are sent to a metering signal conditioning circuit. The circuit is a mature applied spy shadow filter circuit, processed metering signals are sent into a voltage and current phase ADC corresponding to an SOC chip RN2026, the RN2026 can realize a basic metering function, and original ADC data can be transmitted to a business management core through a DMA function of a proprietary SPI. The basic metering function can carry out data interaction through the SPI in butt joint with the main control board.

As shown in fig. 4, it is an a-phase voltage signal conditioning circuit of the present invention; wherein the B, C phase voltage sampling circuit is similar. The working principle diagram is as follows: r24 to R32 are current limiting resistors, and are isolated by PT1 and then pass through a pi-type filter circuit, wherein R22 and R31 are sampling resistors. VAN and VAP are differential signals sent to an RN2026 voltage sampling channel;

FIG. 5 shows an A-phase voltage signal conditioning circuit according to the present invention; wherein B, C phase and zero sequence current sampling circuits are similar. The CT output signal passes through a pi-type filter circuit, wherein R23 and R34 are sampling resistors. IAP and IAN are differential signals sent to a RN2026 current sampling channel;

FIG. 7 is a schematic diagram of a current interleaving circuit employed in the present invention; fig. 8 and 9 are schematic diagrams of operational amplifier circuits adopted by the invention; IA and IA-are secondary side sampling differential signals of an external current transformer, R122 and R125 adopt resistors, R121+ C52 and R130+ C58 are first-order low-pass filter circuits, and V28 and V29 are bidirectional sequential suppressors. Here, a front-end sampling voltage conversion circuit portion is constituted. The single channel D40A, the reverse input resistors R126 and R123, the anti-aliasing capacitor C53, the forward input resistor R131, the direct current bias resistor R133 and the single-ended signal output matching resistor R128 of the operational amplifier SGM8270 form an operational amplifier circuit part. The single channel D40D and the voltage dividing resistors R825 and R820 of the operational amplifier SGM8270 form a voltage follower circuit, and the current output capacity of the direct-current bias voltage Vref _ U1 is improved.

VA +/VA-, VB +/VB-, VC +/VC-; IAA +/IAA-, IBB +/IBB-, ICC +/ICC-, are corresponding three-phase voltage and three-phase current sampling signal input channels respectively. Wherein HT _ CS, HT _ CLK, HT _ DIN and HT _ DOUT are SPI channels of HT7022E to upper management MCU. HT _ PCF, HT _ QCF are the active pulse and the idle pulse signals output by RN2026, respectively.

CS, CLK, DOUT and DIN are special SPI (support DMA) of RN2026, and are used for externally transmitting the data to the service management core or the master control platform, so that the service management core or the master control platform can further operate based on ADC data, and high-level station area monitoring functions such as load identification, fault study and judgment, fault recording and power quality analysis are realized.

The voltage channel and current channel principle of the differential-to-single-ended operational amplifier peripheral circuit are basically consistent, and a current sampling channel is taken as an example for explanation; the circuit comprises a current sampling circuit unit (a circuit secondary side sampling resistor + first-order filtering, a single operational amplifier + direct current bias + reverse amplification) and a voltage sampling circuit unit (a voltage primary side current limiting resistor, a voltage transformer, a voltage secondary sampling resistor + first-order filtering, a single operational amplifier + direct current bias + reverse amplification). The operational amplifier circuit mainly comprises SGM82704 channel operational amplifiers, one SGM82704 can complete differential conversion single-end conversion of 3-path voltage or 3-path current, and the rest 1-path operational amplifier can just be used as a voltage follower to supply power for direct-current configuration voltage, so that 1 SGM82704 channel operational amplifier and auxiliary circuits thereof can be reduced compared with the conventional circuit in general.

In the invention, a high-precision metering chip HT7022E (other SOC metering chips with the same function can also be tried) and a differential-to-single-end operational amplifier circuit are used, so that ADC data is uploaded to an AD port of a service management core in real time through the operational amplifier circuit while basic metering of the metering chip is realized, and a fault studying and judging function is realized.

Under the condition that the main control interface only has 1 path of SPI port or 1 path of USB port, the business management core can realize the transparent transmission function of basic metering and can also realize the platform area monitoring function by using ADC data.

The special software algorithm flow is used for realizing the functions of uploading ADC data, amplifying and conditioning signals, and a signal conditioning circuit consisting of a large number of analog components is eliminated.

The high-precision metering chip HT7022E + differential-to-single-ended operational amplifier circuit combination has the functions of alternate acquisition metering and ADC data real-time uploading.

The business management core of the invention can be cancelled, and analog data can be directly uploaded to the main control layer to realize the monitoring function of the related distribution area.

The low-voltage shunt monitoring device described in the invention can realize the fusion of basic metering and area fault monitoring functions. The device can monitor and collect massive original alternate current data in real time, analyze and process the data, and has the functions of studying and judging voltage loss faults (undervoltage), power failure faults, phase failure faults, voltage overvoltage faults, current overcurrent faults, current loss, single-phase grounding short circuit faults, reverse phase sequence faults, load overload faults, power failure faults and zero-sequence current partial large faults. The method supports transient state (voltage and current) recording, transient state recording, calling recording, switch deflection trigger recording and custom trigger recording, and fully develops the data application value.

The low-voltage shunt monitoring device described in the invention cancels a complex intermediate management chip, changes a special metering chip and operational amplifier circuit mode into the mode, and fully utilizes a mature large-scale integrated circuit to realize the construction of a related functional circuit. A large number of functions realized by the original analog circuit are realized by software algorithm, and the method has the advantages of low cost, small occupied space, high intelligence and the like. In addition, the invention also provides a typical fault studying and judging method of the low-voltage distribution area by combining the principle of the low-voltage shunt monitoring device aiming at the fault characteristics of the low-voltage distribution area.

While the present invention has been described in detail with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.