172results about "Phase sequence/synchronism indication" patented technology

The invention discloses an ultra-high voltage nuclear phase correction method, device and equipment based on multi-source data fusion and a medium, and relates to the technical field of power grids, and the method comprises the steps: firstly obtaining the t-th round of multi-source data and a real phase value of ultra-high voltage equipment; and inputting the multi-source data into the pre-trained neural network model to generate a correction coefficient, correcting a phase value by combining the correction coefficient and the original phase value, and calculating a phase error with a real phase value. If the phase error exceeds the error threshold value and the adjustment frequency does not exceed the adjustment frequency threshold value, adjusting the gain of the acquisition equipment amplifier according to the electric field intensity, and re-acquiring the (t + 1) th round of multi-source data; and outputting a corrected phase value if the phase error reaches the standard. In addition, the correction phase value needs to be rechecked by two persons, and when the deviation exceeds a second threshold value, intelligent contract alarm and frozen combination ring operation are triggered; time deviation and a second phase error can be obtained through the current temperature, and secondary correction is carried out on the original phase value. According to the method, the nuclear phase precision and safety of the ultrahigh-voltage equipment can be improved.

The application provides a power module test method, system, device and medium. The method is applied to a chip test device, the chip test device includes a probe card, the probe card includes a plurality of phase sequence modules, and each phase sequence module is connected with a drive board. For the plurality of phase sequence modules, when it is detected that a target drive board is powered on, the target drive board reads test configuration information from the phase sequence module, the target drive board generates a first target phase sequence drive voltage based on initial phase sequence voltage information in the test configuration information, when a drive instruction is received, the target drive board generates a drive signal, and based on the drive signal, the first target phase sequence drive voltage is transmitted to the power module under test through the phase sequence module at a target pin to drive the power module under test. Therefore, no matter how the drive board is placed, the phase sequence drive voltage generated by the drive board can be accurately matched to the corresponding phase sequence of the device through the power module under test, manual operation errors are reduced, and test safety is ensured.

The invention belongs to the technical field of phase checking instruments, and particularly relates to a phase checking instrument with a phase checking function for a 10-kilovolt ring main unit switch. Comprising a mobile acquisition device and a handheld nuclear phase host, the mobile acquisition device comprises a mobile chassis, the mobile chassis is provided with a main supporting vertical plate, the main supporting vertical plate is provided with a lifting driving assembly, the lifting driving assembly is connected with a lifting mobile side plate, and the lifting mobile side plate is provided with a telescopic driving assembly. The telescopic driving assembly is connected with a telescopic moving side plate, the telescopic moving side plate is provided with a spacing adjusting assembly, the spacing adjusting assembly is connected with two mounting sleeves, the mounting sleeves are internally connected with acquisition emitters, and the acquisition emitters are used for performing signal acquisition on the ring main unit through acquisition points on the ring main unit; the collected information is wirelessly sent to the handheld nuclear phase host; the ring main unit phase checking device can effectively assist workers in phase checking operation of the ring main unit, labor is saved, operation efficiency is improved, and high efficiency of phase checking operation and accuracy of results are guaranteed.

The embodiment of the invention provides a low-voltage transformer area user phase determination method and device, equipment and a medium. The method comprises the following steps: firstly, acquiring a first power supply radius of a power user in a target low-voltage transformer area and first three-phase voltage data of the power user in a first preset duration; determining a second power supply radius of the at least one three-phase user and third three-phase voltage data corresponding to the at least one single-phase user, and then determining a user proportion value corresponding to a target three-phase user of which the second power supply radius of the at least one three-phase user is greater than a first preset threshold value; and finally, determining the phase of the at least one single-phase user according to the third three-phase voltage data corresponding to the at least one single-phase user, the user proportion value and a second preset threshold. According to the method provided by the invention, the determination of the user phase of the low-voltage transformer area is realized, and the identification efficiency and the identification accuracy of the user phase are improved.

The utility model is suitable for the technical field of phase checking instruments, and provides a portable intelligent phase checking instrument, which comprises an insulating rod and a signal transmitter matched with the phase checking instrument, one end of the signal transmitter is provided with a socket matched with the insulating rod in a threaded manner, and the other end of the signal transmitter is provided with a clamping unit. The clamping unit comprises two pincer handles which are arranged in a crossed mode, two pincer heads installed at the ends of the pincer handles and a driving unit for driving the two pincer handles to rotate in a crossed mode, the two pincer handles are rotationally installed in the signal transmitter through an installation shaft, arc-shaped grooves are symmetrically formed in the two pincer heads, and contact ends are arranged in the arc-shaped grooves. When the driving unit in the clamping unit drives the two clamp handles to rotate crosswise, the driving unit can drive the two clamp heads to clamp the line to be subjected to phase checking and enable the contact end to be in stable contact with the line, so that compared with contact with an electric power line in a contact hook mode in the prior art, the influence of strong wind weather on the detection of the phase checking instrument does not need to be worried, and the detection efficiency is improved. And the use and the operation of the nuclear phase instrument are convenient.

A system for discovering the topology and phases of a power distribution system is provided. For example, a group of meters connected to the power distribution system can process sensor data acquired at the meters and generate descriptors based on the processed data, sending the descriptors to a headend system. The headend system can, after receiving descriptors from the individual meters in the system, group the meters to generate groups by applying a clustering algorithm to the descriptors of these meters. The headend system can also compare the current group with past groups to determine the confidence level of the current group, and assign segment identifiers or phase identifiers, or both, to one or more meters based on the confidence level.

The utility model provides a non-contact current nuclear phase device, which relates to the technical field of electric power detection and comprises a three-phase cable, a coil array, a signal receiving and processing device and an upper computer. The coil array, the signal receiving and processing device and the upper computer are electrically connected in sequence, and the coil array is arranged between the signal receiving and processing device and the three-phase cable. According to the utility model, the coil array is arranged between the signal receiving and processing device and the three-phase cable, so that the sensor is prevented from being too close to the cable, the measurement condition is looser, and the installation safety of the measurement device is better guaranteed; each coil group in the coil array is provided with two magnetic core-containing coils of which the sensitive directions are perpendicular to each other, interference signals can be better eliminated, each magnetic core-containing coil contains a manganese-zinc magnetic core, the sensitivity of the coils is enhanced, smaller current can be measured, longer-distance measurement can be realized, and the installation of the measuring device is more convenient.

The utility model discloses a three-phase voltage, frequency and phase sequence detection circuit, and belongs to the technical field of electric power detection. The three-phase voltage, frequency and phase sequence detection circuit comprises an MCU control unit, an A-phase detection circuit, a B-phase detection circuit and a C-phase detection circuit, wherein the A-phase detection circuit, the B-phase detection circuit and the C-phase detection circuit have the same structure. Each detection circuit comprises a voltage sampling circuit and a frequency detection circuit. According to the utility model, the operational amplifier is used for scaling down the input voltage, and the input voltage is skillfully raised to a range which can be accurately sampled by the MCU, compared with a traditional transformer detection method, the size and the weight are greatly reduced, the waveform distortion is extremely small, the characteristics of an original voltage signal are accurately reflected, and the detection precision is greatly improved. The effects of small size, light weight, low cost and high detection precision can be simultaneously achieved.

Method and system for phase detecting of hybrid wye-connected and delta-connected loads in an unbalanced power distribution system. A data-driven event-triggered phase identification algorithm is presented in which the exceeding current fluctuation events are used to build the relationship between the feeder head and the undetermined phase load and mutual information index is used to assess the dependence level of the feeder head on the undetermined phase load. The connected and non-connected phase of wye-connected and delta-connected single-phase load are determined as the phase having highest and lowest dependences of the phases of feeder head on the load, respectively.

Systems and methods, as described herein, relate to a circuit tracer transmitter including an integrated continuity test. In addition, systems and methods, as described herein, relate to communicating data over a conductor that is being tested with a circuit tracer, load continuity tester, and / or an integrated circuit tracer with load continuity tester. In addition, systems and methods, as described herein, relate an integrated receptacle tester in circuit tracing hardware through circuitry and / or logic.

This invention provides a detection device, comprising: a main body; a power receiving terminal; a stop component movably disposed on the main body, wherein when the stop component is in the stop position, it can abut against the power receiving terminal to maintain a conductive state between the power receiving terminal and the detection terminal; when the stop component is in the disengaged position, it separates from the power receiving terminal to separate the power receiving terminal from the detection terminal; and a positioning component movably disposed on the main body or on the stop component, wherein when the positioning component is in the positioning position, it is positioned against the stop component to maintain the stop component's position; and when the positioning component is in the unlocked position, it disengages from the stop component to allow the stop component to move. The technical solution of this application effectively solves the problem of unstable connection between detection devices and electrical equipment in related technologies.

The invention relates to a multifunctional non-contact nuclear phase system, and belongs to the technical field of phase identification of power systems. The system comprises a metal hook power taking module, an amplifying circuit, a comparator, a microcontroller MCU, a Beidou time service module, a liquid crystal display module and a power supply module. The system is suitable for phase checking of closed equipment such as a switch cabinet, a ring main unit, a box transformer substation and a cable branch box, power failure is not needed, and an insulating baffle of a handcart does not need to be opened. The method only depends on zero crossing point detection, does not need standard phase reference, has the characteristics of high precision, strong interference resistance, remote visual operation and the like, and effectively avoids risks of electric shock of personnel, interphase short circuit and equipment damage.

The application discloses a phase checking device, system and method for a power distribution network, and relates to the technical field of phase sequence synchronization indication. The phase checking device comprises a phase checking module, which is used for obtaining the phase sequence of a pre-repair alternating current voltage signal, obtaining the phase sequence of an analog alternating current voltage signal, comparing the phase sequence of the pre-repair alternating current voltage signal with the phase sequence of the analog alternating current voltage signal, and obtaining a phase checking result. The phase checking system comprises the phase checking device and a phase sequence generating device. The phase sequence generating device comprises a phase sequence generating module, which is used for obtaining the phase sequence of the pre-repair alternating current voltage signal and generating the analog alternating current voltage signal with the same phase sequence. The phase checking method comprises a phase checking step, a comparison of the phase sequence of the pre-repair alternating current voltage signal with the phase sequence of the analog alternating current voltage signal, and obtaining of the phase checking result. The phase checking device, system and method improve the efficiency of the phase checking work by comparing the phase sequence of the pre-repair alternating current voltage signal with the phase sequence of the analog alternating current voltage signal.

The invention relates to a line phase checking method, device and equipment, a storage medium and a program product. The method comprises the following steps: modulating an initial carrier signal by adopting a signal modulation parameter to obtain a target carrier signal; injecting the target carrier signal into the target line; acquiring signal data in the target line from the phase to-be-measured point of the target line, and filtering the signal data to obtain a filtered signal corresponding to the target carrier signal; extracting the actual phase of the filtering signal; and determining a nuclear phase result of the target line according to the phase difference between the actual phase and the reference phase. According to the method, phase checking is carried out on the target line by using the characteristic that the carrier signal can stably transmit the phase characteristic in the line, the stability and accuracy of the phase checking result can be improved, and the phase checking efficiency is improved.

The invention provides an intelligent power grid nuclear phase system based on a cloud platform. Relates to the technical field of power system measurement, in particular to the technical field of power system operation and maintenance and power grid nuclear phase. According to the specific implementation scheme, the system comprises a first data collector, at least one second data collector and a server, wherein the first data collector collects reference phase angle information and first Beidou second time information of a reference power grid; the second data acquisition unit acquires measurement phase angle information and second Beidou second time information of the to-be-measured power grid; and the server receives and processes the reference phase angle information of the reference power grid, the measurement phase angle information of the to-be-measured power grid, the first Beidou second time information and the second Beidou second time information, and verifies the initial phase angle of the to-be-measured power grid.

The invention discloses a three-phase electric meter access detection method, device and system and a storage medium, and relates to the technical field of equipment detection.The electric meter is connected to the alternating current side of power conversion equipment, each phase of the electric meter is connected to a current transformer, and based on the split-phase control function of the power conversion equipment, after the power of the power conversion equipment is limited, the three-phase electric meter access detection is completed. According to the three-phase current difference value of the alternating current side of the power conversion equipment before and after power limitation collected by the ammeter, the access position and direction of each phase current transformer of the ammeter are determined, and accurate detection of misconnection of each phase current transformer of the ammeter is realized.

The invention discloses a cable nuclear phase system. The system comprises a first device and a second device. The first device determines whether the head end of the target cable is in phase matching with the superior equipment based on the first image; wherein the head end and the tail end of the target cable are marked with phase identifiers; the upper-level equipment and the lower-level equipment are marked with phase marks; the second device determines whether the tail end of the target cable is in phase matching with the subordinate equipment based on the second image, generates a matching result and sends the matching result to the first device; the first device is used for generating and transmitting phase information to the second device after determining that the head end of the target cable is matched with the phase of the superior equipment and receiving a matching result indicating that the tail end of the target cable is matched with the phase of the subordinate equipment; and the second device is used for evaluating whether the superior equipment and the subordinate equipment are phase-matched based on the phase information. It can be seen that phase matching of a complete link is ensured to be correct comprehensively through phase checking of the head end and the tail end of the target cable and phase checking of the upper-level equipment and the lower-level equipment.

This invention relates to the field of safety protection technology for low-voltage power distribution systems, and discloses a neutral-line fault detection circuit, a neutral-line fault detection method, and a switching device. The neutral-line fault detection circuit provided by this invention adopts a collaborative architecture of hardware detection and software judgment. The hardware side uses a voltage monitoring module to detect the DC voltage between the target phase line and the N-phase, and combines this with an isolation conversion module to achieve level conversion and isolation, outputting a neutral-line fault trip signal. The software side uses a control module to sample the three-phase voltage values ​​and voltage phase angles in real time, and judges the line status based on the level state of the neutral-line fault trip signal, combined with the target phase voltage and phase angle. When it is determined that the N-phase is neutral-line faulted, the control module outputs a signal to control the trip circuit to operate, achieving protection. This invention can accurately trip the neutral line without detecting three-phase balance, uses fewer components, has low cost, and occupies less circuit board space. It can be widely used in reclosing circuit breakers, molded case circuit breakers, and other switching devices, significantly improving reliability and stability.

The invention relates to the technical field of electric power engineering, and provides a power grid phase sequence identification method and device, electronic equipment and a storage medium. The power grid phase sequence identification method comprises the steps that input voltage of a target power grid is sampled according to a preset sampling period, three-phase sampling voltage is obtained, and the three-phase sampling voltage comprises sampling voltage corresponding to each phase; and determining the phase sequence of the target power grid according to the magnitude relationship of the sampling voltages of any two phases in the three-phase sampling voltages and the change trend of the sampling voltage of the remaining phase. According to the method, the magnitude relation of any two phases of sampling voltages in the three phases of sampling voltages and the change trend of the sampling voltage of the remaining phase are analyzed, so that the phase sequences of different power grids can be automatically and effectively identified, the application range of the frequency of the charging pile is expanded, and the power grid adaptability of a machine is improved.

A three-class AC power supply voltage value and phase sequence detection system comprises an MCU, and an AC220V / 50Hz conditioning circuit, an AC115V / 400Hz conditioning circuit, an AC380V / 50Hz conditioning circuit and a protection alarm which are electrically connected with the MCU, the AC220V / 50Hz conditioning circuit comprises a Hall voltage sensor, the input end of the Hall voltage sensor is connected with a conditioning resistor R in series and then is connected with a power supply, the output end of the Hall voltage sensor is connected with a capacitor C55 in series and then is connected with an input port of the MCU, and the protection alarm is electrically connected with the MCU. The output end of the MCU is further connected in series with a divider resistor R55 and then grounded, and the input port of the MCU is connected in series with a resistor R75 and then connected with + 3.3 V and is connected in series with a resistor R74 and then grounded; the AC115V / 400Hz conditioning circuit comprises an instrument amplifier and a voltage feedback amplifier, the input end of the instrument amplifier is connected with a power supply after being connected with a resistance voltage division circuit in series, and the output end of the instrument amplifier is connected with a positive input end of the voltage feedback amplifier after being sequentially connected with a capacitor C13 and a voltage lifting circuit in series; the output end of the voltage feedback amplifier is connected with the input port of the MCU and the negative input end of the voltage feedback amplifier. According to the scheme, voltage values of AC220V / 50Hz, AC115V / 400Hz and AC380V / 50Hz can be acquired in real time, the phase sequences of AC115V / 400Hz and AC380V / 50Hz can be measured, and timely protection and alarm can be realized.

The application relates to the field of nuclear phase devices, and discloses a non-contact sensing-based nuclear phase device and method for a ring main unit (RMU) cabinet, which comprises a cabinet body, first and second sections of bus bars are respectively arranged at the top of the cabinet body, a mobile nuclear phase assembly is arranged in the cabinet body, and a control panel is arranged on one side of the cabinet body, wherein the first section of bus bars comprises A-phase bus bars, B-phase bus bars and C-phase bus bars from left to right, and the second section of bus bars comprises A-phase bus bars, B-phase bus bars and C-phase bus bars from right to left; the mobile nuclear phase assembly comprises a telescopic cylinder fixedly arranged on the inner top wall of the cabinet body, horizontal rods are symmetrically arranged at the output end of the telescopic cylinder, and two sliding rail units are symmetrically connected to the two horizontal rods; the telescopic cylinder can drive the sliding rail units to rotate around the fixed shaft, so that the nuclear phase detection unit can be conveniently moved to the position below the corresponding phase bus bar to be detected in the sliding rail unit, and nuclear phase detection is facilitated.

The invention relates to the technical field of power transformation protection replacement, in particular to a power line loss abnormity monitoring system and monitoring method. The host and the extension sets are provided with communication modules, and the communication modules provide wireless communication links and pulse signals. A power supply circuit, a current acquisition circuit, a leakage current acquisition circuit, a voltage acquisition circuit, a phase sequence measurement circuit, an MCU core control circuit and a 4G communication circuit are integrated in the host and the extension set. Time service and communication are combined into one, an independent high-precision GPS module is omitted, reference pulses are distributed through 4G after Beidou signals are acquired at the outdoor host, and sub-millisecond synchronization can be achieved without receiving satellite signals by the indoor extensions. The phase sequence judgment precision is high, A, B and C three-phase and single-phase user attribution phases can be reliably distinguished, the extension set can be put into use only by clamping a clamp meter, wiring is not needed, relaying is not needed, and an original metering seal does not need to be damaged.

The invention belongs to the technical field of uninterruptible power operation, and provides a nuclear phase and current detection device working method based on an unmanned aerial vehicle and a detection device.A first clamping jaw is provided with an insulating rope, and the insulating rope is far away from and connected with a telescopic assembly; when the detection device needs to be lifted away emergently, the unmanned aerial vehicle continues to lift upwards, the first clamping jaw and the second clamping jaw are opened and lifted away, when the detection device needs to be lifted away from an overhead line in an emergency, the lifting motion does not need to be executed after the opening and closing actions of the clamping jaws are completed, and lifting away is timely; meanwhile, when normal detection is completed, the unmanned aerial vehicle continues to lift upwards, the telescopic assembly retracts and pulls the insulation rope, the first clamping jaw and the second clamping jaw are opened through the upward lifting action of the unmanned aerial vehicle and the retracting and pulling action of the telescopic assembly, the lifting speed is guaranteed, the pulling force on the insulation rope can be reduced, and the safety of the insulation rope is improved. The problem of stress damage caused by long-time and multi-time pulling of the insulating rope is avoided, and the service life of the insulating rope is prolonged.

The invention discloses a cable three-phase unbalanced current detection method based on phase difference, and relates to the field of current sensing, and the method comprises the steps: carrying out the synchronous collection of three-phase current signals of a cable, and carrying out the preprocessing of the collected signals; an improved Hilbert-Huang transform method is adopted, and the instantaneous phase of each phase of current is extracted from the preprocessed three-phase current signals; calculating an instantaneous phase difference between any two phases based on the extracted instantaneous phase of each phase of current, and determining a three-phase current balance state of the cable according to the instantaneous phase difference; when it is judged that the three-phase instantaneous phase difference is in the unbalanced state, the fault type is recognized according to the abnormal mode of the three-phase instantaneous phase difference, corresponding fault response operation is executed, self-adaptive weighted fusion phase extraction of the multi-component signals is achieved through an improved Hilbert-Huang transform method, and the fault detection accuracy is improved by combining instantaneous phase difference calculation and abnormal mode recognition. And high-precision and high-real-time online detection and fault type discrimination of the three-phase imbalance state of the cable are realized.

This utility model discloses a three-phase grid voltage detection circuit, comprising: a switching module, a control module, three phase voltage sampling modules, and two comparison modules. The phase voltage sampling modules sample the phase voltages of the three-phase AC power of the tested grid and convert them into DC voltages. The comparison modules output a first-level signal through their comparison output terminals when the DC voltage is greater than a first voltage, and output a second-level signal through their comparison output terminals when the DC voltage is less than the first voltage. The switching modules turn off in response to the first-level signal to input the DC voltage to the control module, and turn on in response to the second-level signal to input the ground voltage to the control module. The control modules determine whether the three-phase AC power of the tested grid is under-voltage or over-voltage based on the DC voltage, and determine whether a phase is missing in the three-phase AC power of the tested grid based on the ground voltage. This utility model's three-phase grid voltage detection circuit has a simple structure and low cost.

The invention provides a portable test box for imported gyroscopes. A power supply module, and a phase sequence detection module, a power supply indication module, a transformer assembly, a signal measurement module and a 24-core circular connector which are connected with the power supply module through a state switching module are arranged in a box body. The method can separate from other equipment of a heading system to independently test imported gyroscopes, does not need to depend on a whole machine or a heading system core assembly, can directly detect the gyroscopes, and quickly judges whether faults are derived from gyroscope parts or not; the problems that an existing imported helicopter gyroscope test depends on other equipment, fault positioning is slow, test precision is low, maintenance resources are consumed, and normal parts are possibly consumed are solved, the functions of phase sequence detection, power state indication, angle signal resolving display and skew state monitoring are achieved, fault positioning efficiency and test precision are improved, and the test cost is reduced. And the fault positioning time is greatly shortened, the maintenance resource consumption and the normal part loss risk are reduced, and the safety and continuity of the operation of the imported helicopters are guaranteed.

The invention provides a low-voltage active power distribution network user phase sequence identification and control method based on carrier communication, and relates to the technical field of low-voltage power distribution network electric energy quality treatment. Firstly, a special carrier communication network is deployed in a to-be-identified low-voltage distribution area, and operation parameter data of the distribution area are synchronously collected based on the network; after preprocessing the data, constructing a voltage-power phase sequence mapping model; training the model by using the preprocessed data, and extracting a phase sequence mapping matrix from the trained model curing parameters; determining phase sequence categories to which all users belong based on the matrix, and calculating a three-phase unbalance degree; and when the unbalance degree exceeds a preset threshold value, generating a load adjustment scheme, and remotely adjusting the phase sequence category to which the user belongs by using a special carrier communication network. According to the method, the recognition accuracy is improved under the condition that extra prediction calculation is not needed, the efficiency and accuracy of user phase sequence recognition are both considered, and the control precision of user phase sequence control is improved.

The invention provides a device and a method for checking the phase sequence and polarity of an alternating-current motor, and relates to a motor detection technology. The inspection device comprises a shell, a battery and a milliammeter are integrated in the shell, the inspection device further comprises a button switch, a first jointing clamp, a second jointing clamp, a third jointing clamp and a fourth jointing clamp, the button switch and the first jointing clamp are connected into a main loop comprising the battery, and the second jointing clamp is connected to a negative electrode of the battery. And the third jointing clamp and the fourth jointing clamp are respectively connected to two ports of the milliammeter. The phase sequence checking method comprises the following steps of: clamping the head end of a first phase winding of a tested motor by using the first jointing clamp, clamping the head end of a second phase winding after short-circuiting the second jointing clamp and the third jointing clamp, and clamping the head end of a third phase winding by using the fourth jointing clamp; after the main loop is connected, the tested motor is rotated, and the phase sequence is judged by observing the pointer deflection direction of the milliammeter. And during polarity inspection, a motor winding is connected for multiple rounds, and the pointer deflection direction of the milliammeter is observed through electrification.

The invention provides a single-phase three-wire voltage signal acquisition circuit and method, and the circuit is characterized in that a capacitor C1 is connected with a conductive touch panel S1; the capacitor C1 is connected with the first switch K1; the first switch K1 is connected with the resistor R1; the live wire L is connected with the capacitor C2, the third switch K3 and the first output end of the power supply; the third switch K3 is connected with the resistor R3; the zero line N is connected with the capacitor C3, the second output end of the power supply and the common ground wire GND; the protective ground wire PE is connected with the capacitor C2, the capacitor C3 and the second switch K2; the second switch K2 is connected with the resistor R2; the voltage measuring unit V1 is connected with the resistor R1, the resistor R2 and the resistor R4; the resistor R4 is connected with a common ground wire GND; the voltage measuring unit V1 is connected with the resistor R3 and the resistor R5; and the resistor R5 is connected with the common ground wire GND. According to the invention, single-phase three-wire voltage sampling is realized only by using a plurality of discrete components, the circuit structure is simplified, and the cost is reduced.

The invention provides an electric energy meter and method for judging whether a relay can be switched on based on a real load detection circuit, the electric energy meter comprises a detection circuit and a processing module, the detection circuit is used for detecting whether the rear end of the electric energy meter is electrified and whether the time sequence is consistent with that of the front end of the electric energy meter; the processing module performs different actions according to a detection result, the electric energy meter is allowed to be switched on when it is detected that the rear end of the electric energy meter has voltage and the time sequence of the voltage is consistent with the time sequence of the front end of the electric energy meter, and switching on is forbidden when the detected time sequence is inconsistent with the time sequence of the front end of the electric energy meter, so that the short circuit phenomenon is prevented.