A method and system for measuring the voltage angle of a single phase power supply network

Abstract

The application discloses a kind of single-phase power supply network voltage included angle measurement method and system, is specifically related to electronic measurement field.It includes: based on many single-phase electric meters in station area to construct communication network, phase angle request instruction is issued to the first electric meter as reference phase by concentrator, the first electric meter sends phase synchronization data frame carrying target address and synchronization identification to other single-phase electric meters by RS485 bus;Other single-phase electric meters start timer after identifying synchronization data frame, and stop timing when the zero-crossing point of preset direction appears in its access phase line voltage, and the time interval obtained is returned to the first electric meter.The first electric meter synchronously executes zero-crossing detection and obtains reference time interval, calculates the phase angle of each phase voltage relative to reference phase voltage based on multiple time interval difference values and preset power frequency cycle, and uploads phase angle data to concentrator.

Description

Technical Field

[0001] This invention relates to the field of electronic measurement, and specifically to a method and system for measuring the voltage angle of a single-phase power supply network. Background Technology

[0002] Currently, the main power supply lines in the transformer substation are mainly three-phase. Three-phase power supply has a large output power, low line loss, and low power supply cost. It can also meet the needs of industrial electricity. Ordinary households mainly use lighting and small household appliances, which consume less power. Therefore, the power grid mainly supplies single-phase electricity to users' homes through phase splitting, and the electricity meters are also single-phase meters.

[0003] For three-phase AC power supply networks, the phase angle of AC voltage refers to the time offset of the voltage waveform relative to a reference signal (such as the grid synchronization signal or other phase voltages), usually expressed in degrees (°) or radians (rad). Phase angle detection, as an important indicator for power grid monitoring, plays a crucial role in power system operation, control, protection, and new energy grid integration. Its accuracy directly affects grid security, new energy consumption, and the level of industrial automation.

[0004] At the beginning of the power supply of the distribution area, the phase angle of the power grid generally meets the power supply requirements of the power grid. However, at the end of the power supply of the distribution area, the phase state will change due to the difference in the power environment and load. If it is in a phase abnormal state for a long time, the power grid may experience power supply abnormalities. Therefore, it is necessary to collect and statistically analyze the phase angle information at the end of the distribution area.

[0005] At the beginning of the distribution area, the power grid environment is relatively simple, and three-phase meters can be used to detect the voltage angle. The three-phase meter obtains the phase information by synchronously sampling the three-phase voltage and calculating the voltage sampling signal waveforms of the three phases. At the end of the distribution area, single-phase meters are mainly used, and the installation environment of the meters is limited, making it difficult to install three-phase meters, which also leads to an increase in the cost of power grid quality monitoring. Summary of the Invention

[0006] The technical problem this invention aims to solve is that, in the case of existing low-voltage distribution substations where a large number of single-phase energy meters are used, it is impossible to obtain the three-phase power supply voltage angle on-site, or to determine the power quality status and phase-to-phase operating characteristics. The purpose is to provide a method for measuring the voltage angle of a single-phase power supply network. This method solves the problem of how to use multiple single-phase energy meters in the substation area and achieve phase synchronization triggering, zero-crossing time difference measurement, and phase angle calculation via RS485 bus, so that three-phase voltage angle measurement and data uploading can be achieved without adding a new three-phase measuring device or additional wiring.

[0007] This invention is achieved through the following technical solution:

[0008] A method for measuring the voltage angle of a single-phase power supply network is applied to a power supply network including a concentrator or master station system and multiple single-phase meters communicating with the concentrator or master station system. The multiple single-phase meters are respectively connected to different phase lines of a three-phase power supply network, and the single-phase meters form a communication network through an RS485 bus. The method includes the following steps:

[0009] S1, the concentrator or master station system sends a phase angle request command to the first single-phase meter, which serves as the reference phase voltage measurement node;

[0010] S2, after receiving the phase angle request command, the first single-phase meter sends a phase synchronization data frame to at least two other single-phase meters via the RS485 bus. The phase synchronization data frame carries an address field for identifying the target single-phase meter and a data field for identifying the synchronization signal.

[0011] S3, after the at least two other single-phase meters receive the phase synchronization data frame on the RS485 bus, they determine whether a response is required based on the address field. If a response is required, they identify the phase synchronization data frame as a phase synchronization signal based on the data field. They start timing from the arrival time of the phase synchronization signal and stop timing when the voltage signal of the phase line connected to this single-phase meter reaches a zero crossing in a preset direction, thereby obtaining the time interval T of this single-phase meter. They then send the meter number information and the time interval T to the first single-phase meter through the RS485 bus.

[0012] S4, while sending the phase synchronization data frame, the first single-phase meter performs zero-crossing detection on the voltage signal of its connected phase line, starts timing from the moment the phase synchronization signal is sent, and stops timing when the voltage signal of its own phase line reaches the zero-crossing moment in the preset direction, thereby obtaining a reference time interval T1, and receives the time interval T returned by at least two other single-phase meters.

[0013] S5, the first single-phase meter calculates the phase angle of each phase voltage relative to the reference phase voltage according to the preset power frequency cycle based on the reference time interval T1 and the time interval T of the at least two other single-phase meters, and sends the calculated phase angle data of each phase voltage to the concentrator or master station system.

[0014] Furthermore, the multiple single-phase meters include a first single-phase meter, a second single-phase meter, and a third single-phase meter that are respectively connected to phases A, B, and C of the three-phase power supply network. The first single-phase meter is connected to phase A, and the second and third single-phase meters are respectively connected to phase lines different from phase A.

[0015] Furthermore, the phase synchronization data frame includes: a start field, a sending single-phase meter address field, a target single-phase meter address field, a synchronization identifier field, and a verification field; wherein,

[0016] The target single-phase meter address field is used to enable the at least two other single-phase meters to identify whether they are the target single-phase meter when they receive the phase synchronization data frame.

[0017] The synchronization identifier field is used to identify the phase synchronization data frame as a phase synchronization signal when the target single-phase meter is identified.

[0018] Furthermore, the zero-crossing in the preset direction is the negative zero-crossing of the voltage signal;

[0019] The at least two other single-phase meters and the first single-phase meter respectively determine the corresponding negative zero-crossing time by detecting the process of the connected phase line voltage signal crossing from a positive value to a negative value.

[0020] Furthermore, when the at least two other single-phase meters send the time interval T to the first single-phase meter, they use an RS485 bus point-to-point response method, and each response carries the meter number information of the single-phase meter and the time interval data obtained from a single measurement.

[0021] Furthermore, the first single-phase meter calculates the phase angle of each phase voltage, including:

[0022] The time interval between connecting the first single-phase meter to the phase line As a reference time interval, the voltage phase of the first single-phase meter connected to the phase line is selected as the reference phase phase, based on the power frequency cycle. Calculate the voltage phase angle of other phase lines. ,in:

[0023]

[0024] To access the first The time interval of the phase line voltage signal of a single-phase meter. The preset power frequency cycle.

[0025] Furthermore, after receiving the phase angle data of each phase voltage, the concentrator or master station system stores and periodically updates the phase angle data, and archives and manages the phase angle data corresponding to different transformer areas based on preset transformer area identifiers.

[0026] Furthermore, the communication method between the concentrator or master station system and the first single-phase electricity meter includes at least one of RS485 communication, carrier communication PLC and cellular mobile communication 4G, and the first single-phase electricity meter communicates with the at least two other single-phase electricity meters via RS485 bus.

[0027] Furthermore, this also includes:

[0028] The RS485 bus is configured for network initialization, which includes setting the address, baud rate, and verification method of each single-phase meter.

[0029] This invention also provides a system for measuring the voltage angle of a single-phase power supply network, characterized in that it executes the aforementioned method for measuring the voltage angle of a single-phase power supply network, applied to a power supply network including a concentrator or master station system and multiple single-phase meters communicating with the concentrator or master station system, wherein the multiple single-phase meters are respectively connected to different phase lines of a three-phase power supply network, and the single-phase meters form a communication network via an RS485 bus, and the measurement system includes:

[0030] The concentrator or master station system is used to send a phase angle request command to the first single-phase meter, which serves as the reference phase voltage measurement node, and to receive the phase angle data of each phase voltage sent by the first single-phase meter.

[0031] The first single-phase meter is connected to the first phase line and communicates with at least two other single-phase meters via the RS485 bus. When receiving the phase angle request command, it sends a phase synchronization data frame carrying the target single-phase meter address field and synchronization identifier field to the at least two other single-phase meters via the RS485 bus. It performs zero-crossing detection on its own connected phase line voltage signal and obtains a reference time interval T1. It receives the time interval T obtained by the at least two other single-phase meters based on the phase synchronization signal and their respective phase line voltage zero-crossing detections, and calculates the phase angle of each phase voltage relative to the first phase line voltage based on the reference time interval T1 and the time interval T, according to a preset power frequency cycle.

[0032] The at least two other single-phase meters are respectively connected to a phase line different from the first phase line, and communicate with the first single-phase meter through the RS485 bus. When the phase synchronization data frame is received and identified as a phase synchronization signal, the meter obtains the time interval T based on the zero-crossing detection result of the voltage signal of the phase line connected to the single-phase meter, and sends response data carrying the meter number information of the single-phase meter and the time interval T to the first single-phase meter through the RS485 bus.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] This invention can achieve three-phase voltage angle measurement by reusing existing single-phase smart meters and RS485 communication networks, without the need to install three-phase energy meters, synchronous measurement modules or GPS timing equipment, and is compatible with existing transformer substation metering structures, significantly reducing the cost of transformation.

[0035] By utilizing the synchronous data frame triggering mechanism and the time difference calculation method based on zero-crossing detection, the quantized phase angle values ​​between the three-phase voltages A, B, and C can be directly obtained, rather than the traditional method that can only achieve phase identification or waveform similarity analysis, thus providing quantifiable basic parameters for power quality diagnosis.

[0036] Phase alignment is achieved through a "synchronous frame trigger + local zero-crossing timing" method, eliminating the need for GPS, BeiDou timing, or centralized clock system support. This avoids the impact of clock drift on measurement accuracy and improves system adaptability and reliability.

[0037] The system can periodically calculate and report the phase angle, enabling the monitoring of three-phase imbalance, phase load offset, voltage waveform abnormalities, and changes in operating trends in the transformer area, providing support for scheduling optimization, fault location, and adjustment of operating strategies.

[0038] The system architecture supports the connection of any number of single-phase meters and can be applied to three-phase terminal measurement, regional node monitoring and distributed power quality assessment scenarios. It can also serve as the data foundation unit for subsequent distributed monitoring systems. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0040] Figure 1 This is a structural block diagram illustrating the method for measuring the voltage angle of a single-phase power supply network in Example 1.

[0041] Figure 2 The flowchart shows the phase angle acquisition process of the voltage angle measurement method for a single-phase power supply network in Example 1. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0043] Example 1

[0044] A method for measuring the voltage angle of a single-phase power supply network is applied to a power supply network including a concentrator or master station system and multiple single-phase meters communicating with the concentrator or master station system. The multiple single-phase meters are respectively connected to different phase lines of a three-phase power supply network, and the single-phase meters form a communication network through an RS485 bus. The method includes the following steps:

[0045] S1, the concentrator or master station system sends a phase angle request command to the first single-phase meter, which serves as the reference phase voltage measurement node;

[0046] S2, after receiving the phase angle request command, the first single-phase meter sends a phase synchronization data frame to at least two other single-phase meters via the RS485 bus. The phase synchronization data frame carries an address field for identifying the target single-phase meter and a data field for identifying the synchronization signal.

[0047] S3, after the at least two other single-phase meters receive the phase synchronization data frame on the RS485 bus, they determine whether a response is required based on the address field. If a response is required, they identify the phase synchronization data frame as a phase synchronization signal based on the data field. They start timing from the arrival time of the phase synchronization signal and stop timing when the voltage signal of the phase line connected to this single-phase meter reaches a zero crossing in a preset direction, thereby obtaining the time interval T of this single-phase meter. They then send the meter number information and the time interval T to the first single-phase meter through the RS485 bus.

[0048] S4, while sending the phase synchronization data frame, the first single-phase meter performs zero-crossing detection on the voltage signal of its connected phase line, starts timing from the moment the phase synchronization signal is sent, and stops timing when the voltage signal of its own phase line reaches the zero-crossing moment in the preset direction, thereby obtaining a reference time interval T1, and receives the time interval T returned by at least two other single-phase meters.

[0049] S5, the first single-phase meter calculates the phase angle of each phase voltage relative to the reference phase voltage according to the preset power frequency cycle based on the reference time interval T1 and the time interval T of the at least two other single-phase meters, and sends the calculated phase angle data of each phase voltage to the concentrator or master station system.

[0050] In this embodiment, when the system is in operation, the concentrator periodically sends phase angle request commands to the first meter at preset time intervals to trigger a three-phase voltage angle measurement process. Upon receiving the phase angle request command, the first meter immediately sends a phase synchronization data frame to the second and third meters via the RS485 bus. The phase synchronization data frame includes a target meter address field and a synchronization identifier field to ensure that only the target meter responds to this synchronization trigger.

[0051] After receiving the phase synchronization data frame on the RS485 bus, the second and third meters first parse the target address field to confirm that they are the target meters. Then, they perform a secondary judgment on the synchronization identifier field to identify the data frame as a phase synchronization signal. At the same moment the identification is completed, both meters start their internal timers to keep track of the voltage waveform of their respective connected phase lines. They stop timing when a negative zero-crossing point in the preset direction is detected, thus obtaining the time intervals T2 and T3 between the synchronization trigger moment and the negative zero-crossing point of their respective phase voltages. Subsequently, the second and third meters return response data carrying their own meter number information and the measured time interval value to the first meter via the RS485 bus.

[0052] Simultaneously, the first meter starts its internal timer while sending the phase synchronization data frame and performs zero-crossing detection on the A-phase voltage signal it receives. It stops timing when a negative zero-crossing of the A-phase voltage is detected, thus obtaining the reference time interval T1. Subsequently, the first meter sequentially receives time interval data from the second and third meters and calculates the phase angle of the corresponding phase lines of the second and third meters relative to the A-phase voltage based on the proportional relationship between the time interval difference and the power grid frequency cycle.

[0053] After completing the above calculations, the first meter sends the calculated voltage phase angles of phases B and C relative to phase A to the concentrator via the uplink communication link. Upon receiving the phase angle data, the concentrator stores, displays, or performs further analysis and application according to the system configuration. This embodiment achieves accurate acquisition and real-time transmission of the three-phase voltage angles of the transformer substation without adding additional three-phase measuring devices.

[0054] like Figure 1 As shown, in a preferred embodiment, the present invention is applied to a low-voltage three-phase four-wire power distribution network in a certain transformer substation. At the end of the substation, one single-phase smart meter is installed at each of the A, B, and C phase outgoing lines, respectively designated as meter 1, meter 2, and meter 3. The three meters are connected to a concentrator located in the distribution room via an RS485 bus. The concentrator is connected to the upper-level master station via Ethernet or 4G wireless communication to receive and centrally manage the three-phase voltage phase angle data transmitted from each substation. The single-phase power supply network voltage angle measurement method of the present invention is completed collaboratively by the three single-phase meters and the concentrator.

[0055] The multiple single-phase meters include a first single-phase meter, a second single-phase meter, and a third single-phase meter that are respectively connected to phases A, B, and C of the three-phase power supply network. The first single-phase meter is connected to phase A, and the second and third single-phase meters are respectively connected to phase lines different from phase A.

[0056] The phase synchronization data frame includes: a start field, a sending single-phase meter address field, a target single-phase meter address field, a synchronization identifier field, and a verification field; wherein...

[0057] The target single-phase meter address field is used to enable the at least two other single-phase meters to identify whether they are the target single-phase meter when they receive the phase synchronization data frame.

[0058] The synchronization identifier field is used to identify the phase synchronization data frame as a phase synchronization signal when the target single-phase meter is identified.

[0059] like Figure 2 As shown, when other single-phase meters receive a data frame through the RS485 communication channel, they first determine whether the data frame is relevant to the current measurement task and requires a response. If the result is no, the data frame is discarded and the meter continues to wait for the next data frame. If the result is yes, the meter further determines whether the data frame is a phase synchronization signal. When the data frame is not a phase synchronization signal, the process returns to wait for the next communication trigger. When the data frame is identified as a phase synchronization signal, the single-phase meter starts its internal timer and simultaneously performs zero-crossing detection on the connected phase line voltage.

[0060] During the timing process, this single-phase meter continuously monitors the voltage signal. When a negative zero-crossing point in the preset direction is detected, the timing immediately stops, thus obtaining the time interval between the phase synchronization trigger moment and the voltage zero-crossing moment. Subsequently, this single-phase meter returns the recorded time interval to the first single-phase meter via the RS485 communication channel and enters a state of waiting for the next communication trigger.

[0061] In this embodiment, the microcontroller inside each single-phase meter is equipped with a timer module. The counting frequency of the timer is preferably 100kHz to ensure that the resolution of the time interval measurement is better than 10μs. The voltage sampling circuit output of each single-phase meter is connected to the input of a comparator. The zero-crossing interrupt is triggered by the level flip of the comparator output, avoiding the zero-crossing determination delay caused by software polling.

[0062] The zero-crossing in the preset direction is the negative zero-crossing of the voltage signal;

[0063] The at least two other single-phase meters and the first single-phase meter respectively determine the corresponding negative zero-crossing time by detecting the process of the connected phase line voltage signal crossing from a positive value to a negative value.

[0064] When the at least two other single-phase meters send the time interval T to the first single-phase meter, they use an RS485 bus point-to-point response method to send the information, and each response carries the meter number information of the single-phase meter and the time interval data obtained from a measurement.

[0065] The first single-phase meter calculates the phase angle of each phase voltage, including:

[0066] The time interval between connecting the first single-phase meter to the phase line As a reference time interval, the voltage phase of the first single-phase meter connected to the phase line is selected as the reference phase phase, based on the power frequency cycle. Calculate the voltage phase angle of other phase lines. ,in:

[0067]

[0068] To access the first The time interval of the phase line voltage signal of a single-phase meter. The preset power frequency cycle.

[0069] In practical implementation, with a rated power frequency of 50Hz, the voltage period T0 is approximately 20ms. In a certain measurement, the first meter measured a reference time interval T1 of 5.0ms, the second meter measured a time interval T2 of 11.7ms, and the third meter measured a time interval T3 of -1.0ms (taking the previous negative zero-crossing moment). Then, according to the formula...

[0070] ,

[0071] It can be seen that the phase angle of phase B voltage relative to phase A voltage is approximately 120°, and the phase angle of phase C voltage relative to phase A voltage is approximately −120°, which is consistent with the theoretical phase relationship of standard symmetrical three-phase voltage.

[0072] After receiving the phase angle data of each phase voltage, the concentrator or master station system stores and periodically updates the phase angle data, and archives and manages the phase angle data corresponding to different transformer substations based on the preset transformer substation identifier.

[0073] The communication method between the concentrator or master station system and the first single-phase electricity meter includes at least one of RS485 communication, carrier communication PLC and cellular mobile communication 4G, and the first single-phase electricity meter communicates with the at least two other single-phase electricity meters via RS485 bus.

[0074] In this embodiment, the frame structure of the phase synchronization data frame includes: a 1-byte start field (STX), a 1-byte send table address, a 1-byte destination table address, a 1-byte synchronization identifier field, N bytes of reserved data fields, and a 1-byte check field. The synchronization identifier field has a fixed value of 0xA5, used to quickly identify the frame as a phase synchronization data frame in each meter.

[0075] In practice, at time t0, the first meter sends a phase synchronization data frame. After a bus transmission delay, the second and third meters receive the synchronization data frames at times t0+Δt2 and t0+Δt3, respectively, and start timers from these times. The counting stops when their respective phase line voltage signals cross negative zero at times t2z and t3z, yielding time intervals T2 = t2z−(t0+Δt2) and T3 = t3z−(t0+Δt3). The first meter itself then obtains a time interval T1. Since the bus transmission delays Δt2 and Δt3 are common, they cancel each other out when calculating T2−T1 and T3−T1, thus ensuring the accuracy of the phase angle calculation.

[0076] Before performing steps S2 to S5, the procedure further includes:

[0077] The RS485 bus is configured for network initialization, which includes setting the address, baud rate, and verification method of each single-phase meter.

[0078] In summary, this invention provides a voltage angle measurement scheme suitable for single-phase power supply networks. By utilizing existing single-phase meters and RS485 communication networks, it achieves synchronous acquisition and calculation of the three-phase voltage phase difference, completing the quantification measurement of voltage phase angle without the need for additional three-phase measuring devices or synchronization hardware. The technical solution of this invention features simple structure, low deployment cost, minimal installation and modification requirements, and strong adaptability. It can be widely applied to scenarios such as three-phase imbalance monitoring in low-voltage distribution substations, power quality analysis, and equipment operation status assessment. It should be understood that the embodiments described in this invention are only for illustrating the invention and not for limiting the scope of protection of this invention. For those skilled in the art, equivalent substitutions or modifications made without departing from the core idea of ​​this invention should be included within the scope of protection of this invention.

[0079] Example 2

[0080] A system for measuring the voltage angle of a single-phase power supply network, implementing the method for measuring the voltage angle of a single-phase power supply network as described in Embodiment 1, is applied to a power supply network including a concentrator or master station system and multiple single-phase meters communicating with the concentrator or master station system. The multiple single-phase meters are respectively connected to different phase lines of a three-phase power supply network, and the single-phase meters form a communication network via an RS485 bus. The measurement system includes:

[0081] The concentrator or master station system is used to send a phase angle request command to the first single-phase meter, which serves as the reference phase voltage measurement node, and to receive the phase angle data of each phase voltage sent by the first single-phase meter.

[0082] The first single-phase meter is connected to the first phase line and communicates with at least two other single-phase meters via the RS485 bus. When receiving the phase angle request command, it sends a phase synchronization data frame carrying the target single-phase meter address field and synchronization identifier field to the at least two other single-phase meters via the RS485 bus. It performs zero-crossing detection on its own connected phase line voltage signal and obtains a reference time interval T1. It receives the time interval T obtained by the at least two other single-phase meters based on the phase synchronization signal and their respective phase line voltage zero-crossing detections, and calculates the phase angle of each phase voltage relative to the first phase line voltage based on the reference time interval T1 and the time interval T, according to a preset power frequency cycle.

[0083] The at least two other single-phase meters are respectively connected to a phase line different from the first phase line, and communicate with the first single-phase meter through the RS485 bus. When the phase synchronization data frame is received and identified as a phase synchronization signal, the meter obtains the time interval T based on the zero-crossing detection result of the voltage signal of the phase line connected to the single-phase meter, and sends response data carrying the meter number information of the single-phase meter and the time interval T to the first single-phase meter through the RS485 bus.

[0084] The first meter internally includes a voltage sampling module, a zero-crossing detection module, a timer module, and an RS485 communication interface module. The voltage sampling module receives the A-phase voltage through a voltage transformer. The zero-crossing detection module detects the negative zero-crossing moment based on the sampled waveform. The timer module records the count value between the synchronization frame transmission time and the negative zero-crossing moment. The RS485 communication interface module is responsible for receiving phase angle request commands from the concentrator and sending phase synchronization data frames to other meters, as well as receiving response data. The internal structures of the second and third meters are basically the same as the first meter, differing only in the connected phase lines.

[0085] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for measuring the voltage angle of a single-phase power supply network, characterized in that, This invention is applied to a power supply network including a concentrator or master station system and multiple single-phase meters communicating with the concentrator or master station system. The multiple single-phase meters are respectively connected to different phase lines of a three-phase power supply network, and the single-phase meters form a communication network via an RS485 bus. The invention includes the following steps: The concentrator or master station system sends a phase angle request command to the first single-phase meter, which serves as the reference phase voltage measurement node. After receiving the phase angle request command, the first single-phase meter sends a phase synchronization data frame to at least two other single-phase meters via the RS485 bus. The phase synchronization data frame carries an address field for identifying the target single-phase meter and a data field for identifying the synchronization signal. After receiving the phase synchronization data frame on the RS485 bus, the at least two other single-phase meters determine whether a response is required based on the address field. If a response is required, they identify the phase synchronization data frame as a phase synchronization signal based on the data field. They start timing from the arrival time of the phase synchronization signal and stop timing when the voltage signal of the phase line connected to this single-phase meter reaches a zero crossing in a preset direction, thereby obtaining the time interval T of this single-phase meter. They then send the meter number information and the time interval T to the first single-phase meter through the RS485 bus. While sending the phase synchronization data frame, the first single-phase meter performs zero-crossing detection on the voltage signal of its connected phase line. It starts timing from the moment the phase synchronization signal is sent and stops timing when the voltage signal of its own phase line reaches the zero-crossing moment in the preset direction, thereby obtaining a reference time interval T1, and receives the time interval T returned by at least two other single-phase meters. The first single-phase meter calculates the phase angle of each phase voltage relative to the reference phase voltage according to a preset power frequency cycle based on the reference time interval T1 and the time interval T of the at least two other single-phase meters, and sends the calculated phase angle data of each phase voltage to the concentrator or master station system.

2. The method for measuring the voltage angle of a single-phase power supply network according to claim 1, characterized in that, The multiple single-phase meters include a first single-phase meter, a second single-phase meter, and a third single-phase meter that are respectively connected to phases A, B, and C of the three-phase power supply network. The first single-phase meter is connected to phase A, and the second and third single-phase meters are respectively connected to phase lines different from phase A.

3. The method for measuring the voltage angle of a single-phase power supply network according to claim 2, characterized in that, The phase synchronization data frame includes: a start field, a sending single-phase meter address field, a target single-phase meter address field, a synchronization identifier field, and a verification field; wherein... The target single-phase meter address field is used to enable the at least two other single-phase meters to identify whether they are the target single-phase meter when they receive the phase synchronization data frame. The synchronization identifier field is used to identify the phase synchronization data frame as a phase synchronization signal when the target single-phase meter is identified.

4. The method for measuring the voltage angle of a single-phase power supply network according to claim 3, characterized in that, The zero-crossing in the preset direction is the negative zero-crossing of the voltage signal; The at least two other single-phase meters and the first single-phase meter respectively determine the corresponding negative zero-crossing time by detecting the process of the connected phase line voltage signal crossing from a positive value to a negative value.

5. The method for measuring the voltage angle of a single-phase power supply network according to claim 4, characterized in that, When the at least two other single-phase meters send the time interval T to the first single-phase meter, they use an RS485 bus point-to-point response method to send the information, and each response carries the meter number information of the single-phase meter and the time interval data obtained from a measurement.

6. The method for measuring the voltage angle of a single-phase power supply network according to claim 5, characterized in that, The first single-phase meter calculates the phase angle of each phase voltage, including: The time interval between connecting the first single-phase meter to the phase line As a reference time interval, the voltage phase of the first single-phase meter connected to the phase line is selected as the reference phase phase, based on the power frequency cycle. Calculate the voltage phase angle of other phase lines. ,in: ； To access the first The time interval of the phase line voltage signal of a single-phase meter. The preset power frequency cycle.

7. The method for measuring the voltage angle of a single-phase power supply network according to claim 6, characterized in that, After receiving the phase angle data of each phase voltage, the concentrator or master station system stores and periodically updates the phase angle data, and archives and manages the phase angle data corresponding to different transformer substations based on the preset transformer substation identifier.

8. The method for measuring the voltage angle of a single-phase power supply network according to claim 7, characterized in that, The communication method between the concentrator or master station system and the first single-phase electricity meter includes at least one of RS485 communication, carrier communication PLC and cellular mobile communication 4G, and the first single-phase electricity meter communicates with the at least two other single-phase electricity meters via RS485 bus.

9. The method for measuring the voltage angle of a single-phase power supply network according to claim 1, characterized in that, Also includes: The RS485 bus is configured for network initialization, which includes setting the address, baud rate, and verification method of each single-phase meter.

10. A system for measuring the voltage angle of a single-phase power supply network, characterized in that, The method for measuring the voltage angle of a single-phase power supply network according to any one of claims 1 to 9 is applied to a power supply network including a concentrator or master station system and multiple single-phase meters communicating with the concentrator or master station system, wherein the multiple single-phase meters are respectively connected to different phase lines of a three-phase power supply network, and the single-phase meters form a communication network through an RS485 bus, and the measurement system includes: The concentrator or master station system is used to send a phase angle request command to the first single-phase meter, which serves as the reference phase voltage measurement node, and to receive the phase angle data of each phase voltage sent by the first single-phase meter. The first single-phase meter is connected to the first phase line and communicates with at least two other single-phase meters via the RS485 bus. When receiving the phase angle request command, it sends a phase synchronization data frame carrying the target single-phase meter address field and synchronization identifier field to the at least two other single-phase meters via the RS485 bus. It performs zero-crossing detection on its own connected phase line voltage signal and obtains a reference time interval T1. It receives the time interval T obtained by the at least two other single-phase meters based on the phase synchronization signal and their respective phase line voltage zero-crossing detections, and calculates the phase angle of each phase voltage relative to the first phase line voltage based on the reference time interval T1 and the time interval T, according to a preset power frequency cycle. The at least two other single-phase meters are respectively connected to a phase line different from the first phase line, and communicate with the first single-phase meter through the RS485 bus. When the phase synchronization data frame is received and identified as a phase synchronization signal, the meter obtains the time interval T based on the zero-crossing detection result of the voltage signal of the phase line connected to the single-phase meter, and sends response data carrying the meter number information of the single-phase meter and the time interval T to the first single-phase meter through the RS485 bus.

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