Online positioning and monitoring device and method for voltage sag source

Abstract

The invention relates to a voltage sag source online positioning and monitoring device and method, and belongs to the technical field of voltage sag source positioning and monitoring, the device comprises a bottom layer analog input circuit, a middle layer digital control circuit and an upper layer touch control platform, a power distribution network voltage and current transformer signal can be accessed, and signal conditioning, sampling, packaging and transmission can be carried out; the system further comprises a parameter setting module, a real-time acquisition display module, an online positioning monitoring module, a data query module, a data communication module and an offline positioning module, and the system can determine fault types, such as a single-phase grounding fault, a two-phase grounding fault, a three-phase short circuit fault and a two-phase inter-phase short circuit, through real-time data acquisition and analysis; the system is tested and verified through a radiation type power grid model and a hybrid power grid model, the effectiveness and accuracy of the system in different power grid types can improve the efficiency and accuracy of voltage sag source positioning, and stable operation of a power system is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of voltage sag source positioning and monitoring, and in particular relates to an online positioning and monitoring device and method for a voltage sag source. Background Art

[0002] In the power system, voltage sag is a common power quality problem, which refers to the phenomenon that the voltage in the power grid drops below a certain proportion of the rated voltage in a short period of time and then returns to normal levels. Voltage sag may cause performance degradation of sensitive equipment, production interruption and even equipment damage, which has a serious impact on industrial production and daily life. Traditional methods for locating the source of voltage sag mainly rely on manual inspection and post-analysis. They cannot respond immediately after the voltage sag occurs, resulting in a time delay in fault location and affecting the rapid recovery of the power grid. Due to the lack of real-time monitoring and accurate data support, traditional positioning methods are difficult to accurately determine the fault point and need to rely on experience judgment, which increases the risk of misjudgment. When a voltage sag event occurs, traditional monitoring devices cannot effectively process and analyze a large amount of real-time data, which limits the accurate identification of fault types. Existing technical means are often only targeted at specific fault types or power grid structures, lack flexibility and universality, and are difficult to adapt to complex and changing power grid environments. Therefore, effective positioning and monitoring of voltage sag sources are of great significance to ensuring the stable operation of the power grid and improving the quality of power supply.

[0003] In the prior art, a method and device for locating a voltage sag source with a publication number of CN102608493A is used to calculate and generate the node location of the power quality monitor according to the power grid structure, fault type, trigger conditions of the power quality monitor and preset constraints using a particle swarm optimization algorithm; establish a voltage sag source identification model for circuit fault types including three-phase symmetrical short circuit, single-phase short circuit, two-phase short circuit, and two-phase short circuit to ground; calculate the unbalance value of the node according to the three-phase voltage of the node where the power quality monitor is located, and judge the circuit fault type according to the unbalance value; calculate and generate similarity according to the circuit fault type and its corresponding voltage sag source identification model and the voltage change measured by the power quality monitor; compare the similarity to locate the voltage sag source; obtain the voltage change of the nodes around the voltage sag source, and determine the voltage sag distribution domain of the voltage sag source according to the voltage change. However, this method and device lack the ability of real-time monitoring and rapid response, and cannot adapt to the needs of power grid changes in the long term in modern power grid management. Summary of the invention

[0004] The technical problem solved by the present invention is to overcome the defects in the prior art and provide an online positioning monitoring device and method for a voltage sag source.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The method for online positioning and monitoring of voltage sag sources of the present invention comprises the following steps:

[0007] S1: Determine the monitoring target and install the voltage sag source online positioning and monitoring device, select the distribution network that needs to be located and monitored online, and install the voltage sag source online positioning and monitoring device at the key nodes of the distribution network;

[0008] S2: configure the circuit, configure the bottom layer analog input circuit, the middle layer digital control circuit and the upper layer touch control platform;

[0009] S3: Set module parameters, set parameters through the parameter setting module and start the signal sampling module, data transmission module and positioning monitoring system module;

[0010] S4: Collect monitoring data, and collect data through real-time acquisition display module, wave recording module and online positioning monitoring module;

[0011] S5: Process and analyze data, and perform data processing and analysis through the data communication module and the offline positioning module;

[0012] S6: Analyze the disturbance power and determine the fault type. According to the monitored disturbance power value and the azimuth judgment table, determine whether the fault point is located upstream or downstream of the monitoring point, and determine the fault type according to the result;

[0013] S7: The positioning accuracy is verified experimentally through the radial power grid model and hybrid power grid model built in the laboratory.

[0014] The positioning monitoring system module includes a parameter setting module, a real-time acquisition and display module, an online positioning monitoring module, a wave recording module, a data communication module and an offline positioning module.

[0015] Fault types include single-phase grounding fault, two-phase grounding fault, three-phase short circuit fault, and two-phase phase-to-phase short circuit.

[0016] In step S3, the parameters are set by the parameter setting module and the signal sampling module, the data transmission module and the working module are started, which specifically includes the following sub-steps:

[0017] S31: Set the transformation ratio, equipment installation location, voltage phase sequence, and line number parameters of the voltage and current transformer;

[0018] S32: realize the timing sampling function through DSP control, set the sampling frequency and sampling points, the timing sampling frequency is 3.2kHz, and 64 points are sampled in a single cycle;

[0019] S33: Set the ARM controller to transmit data to the touch control platform using TCP / IP communication.

[0020] In step S4, data collection by the real-time collection and display module and the online positioning monitoring module specifically includes the following sub-steps:

[0021] S41: The real-time acquisition and display module displays the voltage and current effective values ​​and waveforms online;

[0022] S42: The waveform recording module records the waveform details of 18 signals for up to 1 second, capturing and recording temporary drops;

[0023] S43: The online positioning monitoring module performs online monitoring and positioning of the temporary drop source.

[0024] The data processing and analysis performed by the data communication module and the offline positioning module in step S5 specifically includes the following sub-steps:

[0025] S51: The data communication module uses TCP / IP protocol to transmit data without packet loss and receive data;

[0026] S52: The offline positioning module restores and searches for the voltage sag record of the previous voltage sag event.

[0027] The voltage sag source online positioning monitoring device described in the present invention includes a hardware module, which includes a bottom-level analog input circuit, a middle-level digital control circuit and an upper-level touch control platform. The bottom-level analog input circuit includes a mutual inductor input signal conditioning circuit and a DC power supply conversion circuit, and the middle-level digital control circuit includes an A / D sampling circuit.

[0028] The underlying analog input circuit also includes a primary PT, a secondary CT and a filter chip.

[0029] The middle-level digital control circuit also includes a data packet transmission circuit under the control of DSP and ARM.

[0030] The upper touch control platform is equipped with a parameter setting module, a real-time acquisition and display module, an online positioning monitoring module, a data query module, a data communication module and an offline positioning module.

[0031] The present invention has the following beneficial effects:

[0032] 1. Improve positioning accuracy. Through the coordinated work of the real-time acquisition and display module, the waveform recording module and the online positioning monitoring module, the voltage sag event can be accurately captured and recorded, thereby improving the accuracy of fault point positioning. The reliability of the positioning results is further ensured through experimental verification of the radial power grid model and the hybrid power grid model built in the laboratory.

[0033] 2. The timing sampling function realized by DSP control ensures the real-time and integrity of the data with a frequency of 3.2kHz and 64 sampling points in a single cycle, so as to quickly respond to voltage sag events.

[0034] 3. Through the data communication module and offline positioning module, the collected data can be effectively processed and analyzed. The TCP / IP protocol is used to ensure the reliability of data transmission, receive data without packet loss, and improve the efficiency and accuracy of data processing.

[0035] 4. It can identify multiple fault types including single-phase grounding fault, two-phase grounding fault, three-phase short circuit fault and two-phase phase-to-phase short circuit, covering most of the fault conditions that may be encountered in the distribution network, enhancing applicability and practicality.

[0036] 5. Bottom-layer analog input circuit, middle-layer digital control circuit and upper-layer touch control platform, wherein the bottom-layer analog input circuit includes a mutual inductor input signal conditioning circuit and a DC power conversion circuit, and the middle-layer digital control circuit includes an A / D sampling circuit, which improves the accuracy and processing speed of signal acquisition.

[0037] 6. The use of ARM controller and TCP / IP communication replaces the traditional RS232 or RS485 communication, significantly improving the data transmission rate and meeting the needs of large data transmission.

[0038] 7. By quickly and accurately locating the source of voltage sag, it helps to take timely measures to reduce the impact of voltage sag on grid stability and reliability and improve the performance of the entire grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the steps of the method for online positioning and monitoring of voltage sag sources;

[0040] Figure 2 This is a schematic diagram of the steps for setting module parameters;

[0041] Figure 3 Schematic diagram of the steps for collecting monitoring data;

[0042] Figure 4 Schematic diagram of the steps for processing and analyzing data;

[0043] Figure 5 It is a schematic diagram of the signal sampling module, data transmission module and positioning monitoring system module;

[0044] Figure 6 This is a schematic diagram of the positioning monitoring system module;

[0045] Figure 7 This is a schematic diagram of the fixed-point sampling process;

[0046] Figure 8 This is the circuit schematic diagram of the radial power grid test model;

[0047] Fig. 9 This is the circuit schematic diagram of the hybrid power grid test model;

[0048] Fig.10 It is a schematic diagram of the hardware module;

[0049] Fig.11 It is a schematic diagram for installing the hardware module;

[0050] Fig.12 This is the schematic diagram of the transformer input signal conditioning circuit;

[0051] Fig.13 It is the schematic diagram of DC power conversion circuit;

[0052] Fig.14 This is the schematic diagram of the A / D sampling circuit; DETAILED DESCRIPTION

[0053] Embodiment 1:

[0054] like Figures 1 to 9 As shown, the voltage sag source online positioning monitoring method of the present invention comprises the following steps:

[0055] S1: Determine the monitoring target and install the voltage sag source online positioning and monitoring device, select the distribution network that needs to be located and monitored online, and install the voltage sag source online positioning and monitoring device at the key nodes of the distribution network;

[0056] S2: configure the circuit, configure the bottom layer analog input circuit, the middle layer digital control circuit and the upper layer touch control platform;

[0057] S3: Set module parameters, set parameters through the parameter setting module and start the signal sampling module, data transmission module and positioning monitoring system module;

[0058] S4: Collect monitoring data, and collect data through real-time acquisition display module, wave recording module and online positioning monitoring module;

[0059] S5: Process and analyze data, and perform data processing and analysis through the data communication module and the offline positioning module;

[0060] S6: Analyze the disturbance power and determine the fault type. According to the monitored disturbance power value and the azimuth judgment table, determine whether the fault point is located upstream or downstream of the monitoring point, and determine the fault type according to the result;

[0061] S7: The positioning accuracy is verified experimentally through the radial power grid model and hybrid power grid model built in the laboratory.

[0062] The positioning monitoring system module includes a parameter setting module, a real-time acquisition and display module, an online positioning monitoring module, a wave recording module, a data communication module and an offline positioning module.

[0063] Fault types include single-phase grounding fault, two-phase grounding fault, three-phase short circuit fault, and two-phase phase-to-phase short circuit.

[0064] In step S3, the parameters are set by the parameter setting module and the signal sampling module, the data transmission module and the working module are started, which specifically includes the following sub-steps:

[0065] S31: Set the transformation ratio, equipment installation location, voltage phase sequence, and line number parameters of the voltage and current transformer;

[0066] S32: realize the timing sampling function through DSP control, set the sampling frequency and sampling points, the timing sampling frequency is 3.2kHz, and 64 points are sampled in a single cycle;

[0067] S33: Set the ARM controller to transmit data to the touch control platform using TCP / IP communication.

[0068] In step S4, data collection by the real-time collection and display module and the online positioning monitoring module specifically includes the following sub-steps:

[0069] S41: The real-time acquisition and display module displays the voltage and current effective values ​​and waveforms online;

[0070] S42: The waveform recording module records the waveform details of 18 signals for up to 1 second, capturing and recording temporary drops;

[0071] S43: The online positioning monitoring module performs online monitoring and positioning of the temporary drop source.

[0072] The data processing and analysis performed by the data communication module and the offline positioning module in step S5 specifically includes the following sub-steps:

[0073] S51: The data communication module uses TCP / IP protocol to transmit data without packet loss and receive data;

[0074] S52: The offline positioning module restores and searches for the voltage sag record of the previous voltage sag event.

[0075] Specifically, the timing sampling TMS320F28335 model DSP control is implemented, the timing sampling frequency is 3.2kHz, and 64 points are sampled in a single cycle. When the DSP cache data reaches the number of sampling points in a single cycle (18 channels, 64 points per cycle, a total of 1152 points), the data is sent to the data cache area and waits for communication upload.

[0076] Specifically, the regularly sampled data is sent to the RAM cache unit, and the program in the ARM control chip is responsible for reading the data in the RAM cache unit and packaging the data and transmitting it to the touch platform. Because the data transmission volume is large, the RS232 or RS485 communication transmission rate does not meet the requirements, and the ARM controller uses TCP / IP communication to transmit the data to the touch platform.

[0077] Specifically, the positioning monitoring system module includes a parameter setting module, a real-time acquisition and display module, an online positioning monitoring module, a data query module, a data communication module, and an offline positioning module. The parameter setting module can set the transformation ratio of the voltage and current transformer, the equipment installation position, the voltage phase sequence, the line number, etc.; the real-time acquisition and display module can display the voltage and current effective value and waveform online; the online positioning monitoring module realizes the online monitoring and positioning of the sag source according to the algorithm in the previous article; the recording module is used for capturing and recording sags, and can record the waveform details of 18 signals for up to 1 second; the data communication module uses the TCP / IP protocol to transmit data to achieve data reception without packet loss; the offline positioning module is used for the later restoration of voltage sag events.

[0078] Specifically, the signal sampling module, data transmission module and positioning monitoring system module adopt the "producer-consumer" model commonly seen in LabVIEW. The "producer-consumer" model is a commonly used data processing mode, in which the "producer" is responsible for data generation and the "consumer" is responsible for data processing. The two are located in different threads. Due to the multi-threaded processing technology of Windows XP, the "producer" and "consumer" can occupy the CPU alternately, ensuring the real-time reception, caching and processing of data synchronously.

[0079] Specifically, the TCP / IP communication function in the "producer" thread is responsible for receiving data transmitted from the lower computer, unpacking the data, converting it into single-precision floating-point numbers, and then breaking it down into 18 signals, and placing the data into a pre-established queue; at the same time, the queue reading function in the "consumer" thread takes out the data put in by the "producer" from the queue, and processes the signal according to program control, including data caching, real-time waveform display, capture of sag events, waveform recording, and online and offline positioning of sag sources.

[0080] Specifically, it also includes a GUI display interface, which is divided into five parts, namely the main wiring diagram, the setting panel, online positioning, offline positioning and system description. The main wiring diagram shows the current location of the device, the branch connected to the device, and the current bus voltage and the effective value of each branch current. When a voltage sag occurs, the corresponding switch of the branch changes from green to red and remains displayed for 30 seconds, and an alarm is issued to remind the staff that a voltage sag event has occurred; the setting interface corresponds to the parameter modification module in the program, which can write the set transformer ratio, sag threshold, etc. into the record file so that the last set parameters can be run at the next startup to avoid repeated settings; the online positioning interface consists of three parts, and the left side shows the running status of the current program, including the current date, voltage and current transformer ratio, device link IP address and port number, voltage phase sequence and queue information, etc. The queue information shows the progress of the current data cache. If the queue data is always increasing during the program running, it means that the "consumer" processes the data too slowly, which is easy to cause queue congestion and system crash. On the contrary, it means that the "consumer" processes faster than the "producer" and the data transmission is complete. The middle part shows the current bus voltage waveform details, the lower part shows the three-phase voltage effective value and program control buttons, which control the program running status. The program can run in three states: idle state, online positioning, and offline positioning. The offline positioning interface is used to restore the temporary sag event and find the temporary sag record; the system description introduces the basic composition of the system.

[0081] Specifically, Figure 8 As shown, a radial power grid test model is built, where T1 is an autotransformer with a transformation ratio of 380V / 200V; T2 is a split transformer with a transformation ratio of 200V / 100V (standard voltage transformer output);

[0082] R1 and R2 are high-power resistor cabinet and sliding resistor, respectively, with resistance values ​​of 40Ω and 30Ω; 4 monitoring points m1~m4 are set, and the reference direction of the monitoring points is Figure 8 The arrows in the middle indicate two fault points f1 and f2, which are realized by AC contactors, and the grounding resistance is 0.5Ω. Two voltage sag positioning monitoring devices were used in the test, each with a set of three-phase voltage and 5 sets of three-phase current, a total of 18 signals.

[0083] Specifically, when point f1 fails, point m1 monitors four types of fault disturbance power curves, and the duration of the fault is determined by the time the contactor button is closed. During the disturbance process, the disturbance power of point m1 under the four types of faults is negative, indicating that the fault point f1 is located downstream of the monitoring point m1 (same reference direction as point m1). All four positioning judgments are correct.

[0084] Specifically, the typical disturbance power values ​​and azimuth judgments monitored by m1, m2, m3 and m4 under the faults of f1 and f2 were tested 8 times in total, with a correct rate of 100%, proving that the voltage sag source locating method based on the polarity of the disturbance power is effective in the radial power grid.

[0085] Specifically, Fig. 9 As shown in the figure, a hybrid power grid test model is built on the basis of the radial power grid test model, and three fault points F1, F2 and F3 and six monitoring points m1 to m6 are set. In order to distinguish f1 from f3, a 2mH three-phase reactor is connected in series at the hand-holding point of the two buses; the reference direction of the monitoring point is Fig. 9 As indicated by the middle arrow, the fault ground resistance is still 0.5Ω.

[0086] Specifically, when faults occurred at points F1, F2, and F3, m1 to m6 monitored typical disturbance power values ​​and made azimuth judgments. A total of 12 tests and 72 judgments were made with an accuracy rate of 95.8%, proving that the voltage sag source locating method based on the disturbance power polarity is also effective in hybrid power grids.

[0087] Specifically, when the F1 point fails, the disturbance power measured by the monitoring point m5 is both positive and negative, and low-frequency oscillation occurs during the fault. The oscillation frequency f = 1 / (0.4796-0.3573) = 8.18 Hz, that is, the disturbance voltage and disturbance current signals are composed of the superposition of the power frequency signal and the low-frequency signal. The disturbance power components to be solved include the low-frequency oscillation AC part and the DC part. The DC part is mainly composed of the disturbance power in the non-oscillation state of the system, which is an effective component for locating the temporary sag source. Based on the oscillation frequency, the average value of the disturbance power of the entire cycle is obtained, and the temporary sag source is located according to the polarity of the average value. The disturbance power obtained when the F1 point is a three-phase short circuit and a two-phase short circuit fault is -68.9 W and -7.9 W, respectively, indicating that the fault point f1 is located downstream of the monitoring point m5 and is accurately located.

[0088] Specifically, the accuracy of sag source positioning is verified through radial power grid test models and hybrid power grid test models.

[0089] Embodiment 2:

[0090] like Figures 10 to 14 As shown, the voltage sag source online positioning monitoring device described in the present invention includes a hardware module, and the hardware module includes a bottom-level analog input circuit, a middle-level digital control circuit and an upper-level touch platform. The bottom-level analog input circuit includes a mutual inductor input signal conditioning circuit and a DC power supply conversion circuit, and the middle-level digital control circuit includes an A / D sampling circuit.

[0091] The underlying analog input circuit also includes a primary PT, a secondary CT and a filter chip.

[0092] The middle-level digital control circuit also includes a data packet transmission circuit under the control of DSP and ARM.

[0093] The upper touch control platform is equipped with a parameter setting module, a real-time acquisition and display module, an online positioning monitoring module, a data query module, a data communication module and an offline positioning module.

[0094] Specifically, the secondary side signal (100V / 5A) of the voltage and current transformer of the distribution network is connected to the voltage and current transformer in the device through the transformer input signal conditioning circuit in the bottom analog input circuit. Up to 3 voltage signals and 15 current signals can be connected. The PT adopts the ZM-GPT model with a voltage transformer ratio of 120V / 3.53V, which ensures that the secondary transformer coil is not saturated and the signal is not distorted when the voltage of the primary transformer outlet segment is normal or temporarily increased; the transformer signal outlet is connected to the filter chip MAX293EXE, which is an 8th-order low-pass switched capacitor filter. The signal is transmitted to the upper digital control circuit after filtering.

[0095] Specifically, the DC power conversion circuit is connected to an external 12V DC power supply, which is converted into 5V / ±5V through two DC / DC (direct current-direct current) conversion modules to power the filter chip and other chips; on the other hand, it powers the touch platform.

[0096] Specifically, the A / D sampling circuit in the middle-level digital control circuit uses a 16-bit high-precision A / D sampling chip (AD7606) and performs 18-channel sampling at the same time, which can enable one device to monitor multiple output lines at the same time.

[0097] Specifically, the transformer input signal conditioning circuit in the underlying analog input circuit is responsible for receiving the voltage and current transformer signals from the distribution network and performing necessary conditioning to ensure the stability and accuracy of the signal. The input signal range can handle voltage and current signals up to 100V / 5A. Signal conditioning includes impedance matching, signal amplification, and filtering to adapt to subsequent A / D sampling circuits. The transformer model uses the ZM-GPT model for PT and the ZM-GCT model for CT to ensure that the secondary transformer coil is not saturated and the signal is not distorted under normal or temporary voltage rise conditions.

[0098] Specifically, the DC power conversion circuit in the underlying analog input circuit provides a stable DC power supply for the entire underlying analog input circuit. The input voltage can accept a 12V DC power supply, and the output voltage can be converted into 5V / ±5V through a DC / DC conversion module to power the filter chip and other chips. It has power supply stability, and has overvoltage, undervoltage, and short-circuit protection functions to ensure safe and stable operation of the circuit.

[0099] Specifically, the primary PT and secondary CT are used to convert high voltage and large current into low voltage and small current suitable for measurement. The PT transformation ratio is 120V / 3.53V, ensuring that the secondary transformer coil is not saturated when the voltage of the primary transformer outgoing line segment is normal or temporarily increased. The CT transformation ratio selects a suitable transformation ratio according to the actual current size to adapt to different current measurement requirements.

[0100] Specifically, signal synchronization and clock distribution ensure clock synchronization of all sampling channels, avoid phase errors during sampling, and ensure clock jitter with a clock accuracy of less than 1 picosecond, ensuring high accuracy and synchronization of sampling. A high-performance clock distributor is used to support synchronous sampling of multiple channels.

[0101] Specifically, it provides isolation between analog signals and digital circuits to prevent electrical interference and voltage re-injection, provides an isolation level of up to 5kV, ensures safe signal transmission, and uses optocoupler isolation or magnetic isolation technology, which can be selected according to actual needs.

[0102] Specifically, the signal conditioned by the bottom-level analog input circuit is converted into a digital signal through an A / D sampling circuit, and then transmitted to the middle-level digital control circuit through a high-speed interface. The upper-level touch platform receives the digital signal from the middle-level digital control circuit through a data communication module, and performs display and further data analysis.

[0103] Specifically, the digital signal processor (DSP) in the middle-level digital control circuit is responsible for implementing the timing sampling function to ensure the real-time and integrity of the data. The timing sampling frequency is 3.2kHz to ensure that rapidly changing voltage sag events can be captured. The ARM controller is responsible for packaging the data sampled by the DSP and transmitting it to the touch platform through the TCP / IP protocol.

[0104] Specifically, a data communication module can also be set in the middle-level digital control circuit to be responsible for receiving and sending data, ensuring accurate transmission of data between devices. The communication interface uses an Ethernet interface, supports 10 / 100Base-T Ethernet communication, and the communication rate can reach up to 100Mbps to meet the needs of large-scale data transmission. It also supports TCP / IP protocol to ensure the reliability and stability of data transmission.

[0105] Specifically, the A / D sampling circuit in the middle-level digital control circuit converts the conditioned analog signal into a digital signal for processing by the middle-level digital control circuit. It uses a 16-bit high-precision A / D sampling chip (AD7606) to ensure high-precision conversion of the signal, supports 18-channel simultaneous sampling, and realizes parallel processing of multiple signals up to 100kHz, meeting the sampling requirements of rapidly changing signals.

[0106] Specifically, digital logic circuits include combinational logic circuits and sequential logic circuits, which are used to implement complex digital control logic. Combinatorial logic circuits can use half adders and full adders to implement basic arithmetic operations, and sequential logic circuits can use triggers and counters to implement timing control and data storage.

[0107] Specifically, a power management circuit can also be set to provide a stable power supply for the middle-level digital control circuit, and perform power conversion and distribution. The power conversion can use a non-isolated step-down switching circuit such as LM2576 or LM2596 to provide a stable DC output. At the same time, the output voltage can be set by adjusting the feedback terminal resistance, which is suitable for different power supply requirements.

Claims

1. A method for online positioning and monitoring of voltage sag sources, characterized in that: The following steps are involved: S1: Determine the monitoring target and install the voltage sag source online positioning and monitoring device, select the distribution network that needs to be located and monitored online, and install the voltage sag source online positioning and monitoring device at the key nodes of the distribution network; S2: configure the circuit, configure the bottom layer analog input circuit, the middle layer digital control circuit and the upper layer touch control platform; S3: Set module parameters, set parameters through the parameter setting module and start the signal sampling module, data transmission module and positioning monitoring system module; S4: Collect monitoring data, and collect data through real-time acquisition display module, wave recording module and online positioning monitoring module; S5: Process and analyze data, and perform data processing and analysis through the data communication module and the offline positioning module; S6: Analyze the disturbance power and determine the fault type. According to the monitored disturbance power value and the azimuth judgment table, determine whether the fault point is located upstream or downstream of the monitoring point, and determine the fault type according to the result; S7: The positioning accuracy is verified experimentally through the radial power grid model and hybrid power grid model built in the laboratory.

2. The method for online positioning and monitoring of voltage sag sources according to claim 1, characterized in that: The positioning monitoring system module includes a parameter setting module, a real-time acquisition and display module, an online positioning monitoring module, a wave recording module, a data communication module and an offline positioning module.

3. The method for online positioning and monitoring of voltage sag sources according to claim 1, characterized in that: The fault types include single-phase grounding fault, two-phase grounding fault, three-phase short circuit fault, and two-phase interphase short circuit.

4. The method for online positioning and monitoring of voltage sag sources according to claim 1, characterized in that: In step S3, the parameters are set by the parameter setting module and the signal sampling module, the data transmission module and the working module are started, which specifically includes the following sub-steps: S31: Set the transformation ratio, equipment installation location, voltage phase sequence, and line number parameters of the voltage and current transformer; S32: realize the timing sampling function through DSP control, set the sampling frequency and sampling points, the timing sampling frequency is 3.2kHz, and 64 points are sampled in a single cycle; S33: Set the ARM controller to transmit data to the touch control platform using TCP / IP communication.

5. The method for online positioning and monitoring of voltage sag sources according to claim 1, characterized in that: The data acquisition by the real-time acquisition display module and the online positioning monitoring module in step S4 specifically includes the following sub-steps: S41: The real-time acquisition and display module displays the voltage and current effective values ​​and waveforms online; S42: The waveform recording module records the waveform details of 18 signals for up to 1 second, capturing and recording temporary drops; S43: The online positioning monitoring module performs online monitoring and positioning of the temporary drop source.

6. The method for online positioning and monitoring of voltage sag sources according to claim 1, characterized in that: The data processing and analysis performed by the data communication module and the offline positioning module in step S5 specifically includes the following sub-steps: S51: The data communication module uses TCP / IP protocol to transmit data without packet loss and receive data; S52: The offline positioning module restores and searches for the voltage sag record of the previous voltage sag event.

7. A voltage sag source online positioning monitoring device, based on a voltage sag source online positioning monitoring method according to any one of claims 1 to 6, characterized in that: It includes a hardware module, which includes a bottom-level analog input circuit, a middle-level digital control circuit and an upper-level touch control platform. The bottom-level analog input circuit includes a mutual inductor input signal conditioning circuit and a DC power conversion circuit, and the middle-level digital control circuit includes an A / D sampling circuit.

8. The voltage sag source online positioning monitoring device according to claim 7, characterized in that: The bottom layer analog input circuit also includes a primary PT, a secondary CT and a filter chip.

9. The voltage sag source online positioning monitoring device according to claim 7, characterized in that: The middle-level digital control circuit also includes a data packaging transmission circuit under the control of DSP and ARM.

10. The voltage sag source online positioning monitoring device according to claim 7, characterized in that: The upper touch control platform is provided with a parameter setting module, a real-time acquisition and display module, an online positioning monitoring module, a data query module, a data communication module and an offline positioning module.

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