Method, System, Device and Storage Medium for Locating Short-Circuit Fault Sections in Oilfield Distribution Networks

Abstract

The present invention belongs to the technical field of power system distribution network fault data identification, and discloses a method, a system, a device and a storage medium for locating a short-circuit fault section of an oilfield distribution network. The method includes: using a measurement terminal on the load side of the oilfield to measure the line voltage amplitudes of each measurement node on the load side of the system before and after the short-circuit fault, and determining the fault type and the fault phase based on the characteristics of the line voltage amplitudes of the measurement nodes on the load side before and after the fault. When a two-phase short circuit occurs, combining the network topology structure, the line parameters and the line voltage amplitudes of each measurement node on the load side, calculate the magnitude of the positive-sequence current fault component on the medium-voltage side. And determine the short-circuit fault section of the distribution network. When a three-phase short circuit occurs, perform a fault section location criterion to determine the short-circuit fault section of the distribution network. The present invention effectively judges the short-circuit fault type and locates the fault occurrence position to a section, and finally locates the fault between two adjacent measurement nodes on the load side.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system distribution network fault data identification, and particularly relates to a method, system, device and storage medium for locating short-circuit fault sections in an oilfield distribution network. Background Art

[0002] The oilfield distribution network is at the end of the power supply system, directly facing the electrical equipment, and is a key link to ensure power supply reliability and improve operation economy. With the development of the oil industry, the demand for electricity is increasing continuously. However, due to practical problems such as geography and climate in China, there are many faults in the distribution lines of the oilfield power grid in actual applications, which not only have an adverse impact on actual production but also cause certain economic losses. The fault location system can accurately locate the fault section and fault type, and quickly realize maintenance and emergency repair, which is beneficial to improving the reliability and efficiency of the oilfield power grid power supply, thereby improving the overall power supply quality of the oilfield power grid and increasing economic benefits.

[0003] Most of the oilfield distribution networks adopt single-source radial network power supply, which has the characteristics of long lines, wide distribution, complex line structures, many branch lines, scattered loads, unfixed line structures, and rapid changes. In the traditional fault judgment process, most distribution networks use the method of cutting off power supply to each line one by one to determine the fault line. After selecting the fault line, patrol workers are then sent to the site to search for the fault location along the line, and then the fault is isolated and removed. Such a method requires a relatively long positioning time due to the participation of manual labor, and the time consumed by these methods far exceeds the time consumed for fault repair, resulting in a long fault power outage time. In addition, the whole line is generally powered off during line maintenance, which has a great impact on oilfield production. In recent years, the rapid development of intelligent distribution networks has provided technical support for solving the existing problems of oilfield power grids. The fault location algorithm based on FTU (feeder terminal unit) can achieve rapid fault isolation, reduce the impact of fault lines on healthy lines, narrow the power outage range, and has good application value for oilfields with huge economic losses once power outages occur.

[0004] Through the above analysis, the problems and defects of the existing technology are as follows:

[0005] (1) In the existing technology, fault location based on FTU has high costs, high requirements for information synchronization in location, and low fault location accuracy.

[0006] (2) In the existing technology, when measuring the phase during section location of the fault occurrence location, additional monitoring facilities need to be added. When judging the short-circuit fault type and performing section location of the fault occurrence location, it cannot accurately locate between the measurement nodes on both sides of adjacent loads, and the location speed is slow.

[0007] (3) At present, the transformers in the 10kV-class oilfield distribution network generally adopt the DY connection method, and the neutral point on the load side is not grounded. Therefore, the phase voltage data cannot be measured on the load side. Summary of the Invention

[0008] To overcome the problems existing in the related technologies, the disclosed embodiments of the present invention provide a method, system, device, and storage medium for locating short-circuit fault sections in an oilfield distribution network, specifically relating to a method and system for locating short-circuit fault sections in an oilfield distribution network based on the line voltage amplitude on the load side. Based on the above background of oilfield distribution network fault location, the object of the present invention is to obtain the line voltage amplitudes on each load side before and after the short-circuit fault using the measurement terminals on the load side of the oilfield, and according to the network topology structure and load distribution, combined with the fault phase selection result, horizontally compare the distribution law of the line voltage on the load side to determine the short-circuit fault section of the distribution network. The present invention measures the line voltage amplitude before and after the fault based on the monitoring terminal on the load side, uses limited information, does not require measuring the phase, does not require adding additional monitoring facilities, combines the line parameters with the fault phase selection result, realizes the location of the short-circuit fault section, reduces the difficulty of applying the fault location method in the oilfield distribution network, and improves the speed of oilfield distribution network fault location.

[0009] The technical solution is as follows: A method for locating short-circuit fault sections in an oilfield distribution network based on the line voltage amplitude on the load side includes the following steps:

[0010] S1. Based on the distribution characteristics of the line voltage amplitude on the load side after a short-circuit fault occurs on the medium-voltage side, use the line voltage amplitude of the measurement nodes on the load side to judge the fault type and fault phase.

[0011] S2. According to the fault phase selection result, when a two-phase short circuit occurs, use the line voltage amplitude of the measurement nodes on the load side to calculate the positive-sequence current fault component on the medium-voltage side; according to the distribution characteristics of the calculated positive-sequence current fault component on the medium-voltage side, determine the fault occurrence section to achieve fault location.

[0012] S3. According to the fault phase selection result, when a three-phase short circuit occurs, horizontally compare the difference in line voltage amplitude between adjacent measurement nodes on the load side, and determine the fault occurrence section based on the distribution characteristics of the difference in line voltage amplitude between adjacent measurement nodes on the load side to achieve fault location.

[0013] In one embodiment, in step S1, when the data of the monitoring terminal on the load side meets the startup criterion, if the magnitudes of the three line voltage amplitudes at any load-side measurement node i are equal, it is determined that a three-phase short-circuit fault has occurred in the system; if the line voltage amplitude of phase AB at any load-side measurement node i remains unchanged before and after the fault, it is determined that a BC two-phase short-circuit fault has occurred in the system; if the line voltage amplitude of phase BC at any load-side measurement node i remains unchanged before and after the fault, it is determined that a BC two-phase short-circuit fault has occurred in the system; if the line voltage amplitude of phase CA at any load-side measurement node i remains unchanged before and after the fault, it is determined that an AB two-phase short-circuit fault has occurred in the system.

[0014] In one embodiment, when a BC two-phase short circuit occurs, the expression of the line voltage amplitude at the measurement node i on the load side of any of BC is as follows:

[0015]

[0016] wherein, the measurement node on any load side is i, and the three-phase voltages at the medium voltage side of the node before the fault are respectively the transformation ratio of the transformer is n, the mutual impedance between the node and the fault point is Z if , and the fault current is The voltage during normal operation of this node is obtained from the line voltage amplitude of the load side AB after the fault. Let the pre-fault phase A voltage obtained be 0 phase, and the pre-fault three-phase voltages are obtained based on the phase A voltage; the transformation ratio of the transformer is known, and the product of the mutual impedance Z if and the fault current is regarded as a variable, and this variable is defined as

[0017] For any measurement node on the load side, taking the line voltage amplitude of the load side as the dependent variable, the amplitude and phase of are used as independent variables to generate two equations Solve correspondingly the two variables of the amplitude and phase, then the corresponding to each measurement node on the load side of the system can be obtained according to the line voltage amplitude of the load side

[0018] The difference between the corresponding of any two adjacent measurement nodes on the load side is Subtracted by When the positive-sequence fault current flows into the fault point, it is the voltage difference between these two adjacent measurement nodes on the load side; define the voltage difference between the adjacent measurement nodes mn as The voltage difference between each section is obtained Combined with the line topology and line parameters, use Divided by the line impedance between mn to obtain the positive-sequence current fault component between each section.

[0019] In one embodiment, in step S2, when a two-phase short circuit occurs, in the process of determining the fault section according to the distribution characteristics of the positive-sequence current fault component of the medium voltage side to realize fault location, the voltage of the measurement node n on the load side is equal to the voltage at the fault point f, Suppose the calculated value of the positive-sequence current fault component in the mn section is Then: And

[0020] Based on this distribution characteristic, the two-phase short-circuit location criterion for a non-branched line is as follows: among all sections with a positive-sequence current fault component less than 10% of the positive-sequence current fault component of the first section at the line head, the upstream section of the section closest to the power source point is the fault occurrence location. If there is no section meeting the condition and the positive-sequence current fault component of the last section at the line end is less than that of the upstream section, then the last section at the line end is the fault occurrence section.

[0021] According to the fault location analysis for a non-branched line, the positive-sequence current fault component of each section can be obtained based on the line voltage amplitude on the load side. Among them,

[0022] Based on this distribution characteristic, the two-phase short-circuit location criterion for a branched line is as follows: First, apply the non-branched line location criterion to the main line to determine the fault occurrence location. If there is no branch downstream of the fault section, then locate this section as the fault occurrence section. If there is a branch downstream of the fault section, starting from the power source point and ending at the end node of this branch, apply the non-branched line location criterion to determine the fault occurrence location. If it is determined that the fault occurrence section is the same as the main line, then locate this section as the fault occurrence section. If it is determined that there is still a branch downstream of the fault occurrence section, repeat this process until there is no branch downstream of the located section.

[0023] In one embodiment, in step S3, during a three-phase short circuit, the line voltage amplitude on the load side monotonically decreases from the power source point to the fault point. Based on this distribution law, using any line voltage at each load side measurement node and considering the voltage drop caused by the load current, the three-phase short-circuit location criterion is determined as follows: Calculate the absolute value of the difference between the line voltage amplitudes at adjacent load side measurement nodes. Among all sections where the line voltage amplitude first appears less than the set value, the upstream section of the section farthest from the power source point is the fault occurrence section.

[0024] Another object of the present invention is to provide a system for locating short-circuit fault sections in an oilfield distribution network based on the line voltage amplitude on the load side, which implements the method for locating short-circuit fault sections in an oilfield distribution network based on the line voltage amplitude on the load side. The system for locating short-circuit fault sections in an oilfield distribution network based on the line voltage amplitude on the load side includes:

[0025] A fault location startup module for recording the line voltage amplitude on the load side and starting the fault location process when the line voltage mutation amount is greater than the set value;

[0026] A fault type judgment module for judging the fault type using the line voltage amplitudes before and after the fault and judging the fault phase when a two-phase short-circuit fault occurs in the system;

[0027] A two-phase short-circuit fault section location module for calculating the positive-sequence current fault component on the medium-voltage side using the line voltage on the load side and determining the two-phase short-circuit fault occurrence section based on the distribution characteristic of the positive-sequence current fault component on the medium-voltage side;

[0028] The three-phase short-circuit fault section location module is used to determine the section where the three-phase short-circuit fault occurs based on the lateral comparison of the line voltage amplitude differences of adjacent nodes on the load side and the distribution characteristics of the line voltage amplitude differences on the load side.

[0029] In one embodiment, the oilfield distribution network short-circuit fault section location system based on the line voltage amplitude on the load side further includes a master station and a load-side monitoring terminal;

[0030] The load-side monitoring terminal uploads the data of the fault type and fault phase determined based on the line voltage amplitude characteristics of the load-side measurement nodes before and after the fault to the master station. After a short-circuit fault occurs on the medium-voltage side, the system voltage drops. When the line voltage amplitude of the load-side measurement node drops to 90% of the rated voltage, the fault location process starts, and at the same time, two cycles at T1 moment after the fault moment and T2 moment before the fault moment are read as the calculation data for fault phase selection and fault location.

[0031] Another object of the present invention is to provide a computer device, which includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor executes the oilfield distribution network short-circuit fault section location method based on the line voltage amplitude on the load side.

[0032] Another object of the present invention is to provide a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the oilfield distribution network short-circuit fault section location method based on the line voltage amplitude on the load side.

[0033] Another object of the present invention is to provide a feeder terminal device for oilfield distribution network short-circuit fault section location. When the feeder terminal device is implemented on an electronic device, it provides a user input interface to implement the oilfield distribution network short-circuit fault section location method based on the line voltage amplitude on the load side.

[0034] Combining all the above technical solutions, the advantages and positive effects of the present invention are as follows:

[0035] First, aiming at the technical problems existing in the above-mentioned prior art and the difficulty of solving this problem, closely combining the technical solution to be protected by the present invention and the results and data in the R & D process, etc., analyze in detail and deeply how the technical solution of the present invention solves the technical problems and the creative technical effects brought after solving the problems. The oilfield distribution network short-circuit fault section location method and system based on the line voltage amplitude on the load side provided by the present invention have significant differences compared with the traditional location methods:

[0036] At present, the fault section location of the distribution line mainly relies on the feeder terminal unit to carry out, and can only locate the fault between two adjacent feeder terminal units. Moreover, the installation of the feeder terminal has a large investment and high cost. The oilfield distribution network short-circuit fault section location method and system based on the load-side line voltage amplitude provided by the present invention only need to use the existing load-side monitoring terminals of the oilfield distribution network to measure the load-side line voltage amplitude, without measuring the phase and without adding additional monitoring facilities, and can effectively judge the short-circuit fault type and locate the fault occurrence position to the section between two adjacent load-side measurement nodes.

[0037] Traditional location methods usually use the Supervisory Control and Data Acquisition (SCADA) system to receive fault information, and use algorithms such as matrix algorithms and artificial intelligence algorithms to analyze and process the fault location problem. Finally, the position of the fault section is solved. In a complex network structure, the calculation amount is large, and the fault location error is large in the case of information distortion or information loss. The oilfield distribution network short-circuit fault section location method and system based on the load-side line voltage amplitude provided by the present invention do not require a complex calculation process, occupy little computer memory, have a fast calculation speed, and have high fault location fault tolerance in the case of information distortion or information loss.

[0038] Second, regarding the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by the present invention are as follows: The present invention proposes an oilfield distribution network short-circuit fault section location method and system based on the load-side line voltage amplitude, which can correctly identify the fault occurrence section, use the line voltage amplitude obtained by each load-side monitoring device to realize the fault section location, and locate the fault between two adjacent load-side monitoring devices. The location result is more accurate and has better stability. The present invention provides a key technology for realizing the fast location of medium-voltage side short-circuit faults based on load-side information, which can further improve the power supply reliability of the system and is beneficial to the further development of the oilfield distribution network.

[0039] Third, as the creative auxiliary evidence of the claims of the present invention, it is also reflected in: aiming at the problem of limited in-depth utilization of the data of the low-voltage station area integration terminal, the present invention, without adding additional equipment, uses the low-voltage side line voltage data to judge the operation characteristics of the medium-voltage side of the power grid, and narrows the location range to the adjacent load-side integration terminal, providing assistance for oilfield production. Brief Description of the Drawings

[0040] The drawings here are incorporated into the specification and form a part of this specification, showing the embodiments in line with the present disclosure, and are used together with the specification to explain the principles of the present disclosure.

[0041] Figure 1 It is a flowchart of the oilfield distribution network short-circuit fault section location method based on the load-side line voltage amplitude provided by the embodiment of the present invention;

[0042] Figure 2 It is a schematic diagram of an oilfield distribution network short - circuit fault section location system based on the load - side line voltage amplitude provided by an embodiment of the present invention;

[0043] Figure 3 It is a schematic diagram of the principle of an oilfield distribution network short - circuit fault section location method based on the load - side line voltage amplitude provided by an embodiment of the present invention;

[0044] Figure 4 It is a schematic diagram of terminal data transmission provided by an embodiment of the present invention;

[0045] Figure 5 It is a schematic diagram of cycle selection provided by an embodiment of the present invention;

[0046] Figure 6 It is a schematic diagram of the location criterion for a non - branched line provided by an embodiment of the present invention;

[0047] Figure 7 It is a schematic diagram of the location criterion for a branched line provided by an embodiment of the present invention;

[0048] Figure 8 It is an oilfield distribution network topology diagram provided by an embodiment of the present invention;

[0049] Figure 9 It is a distribution diagram of the positive - sequence current fault component of the main line of fault 1 provided by an embodiment of the present invention;

[0050] Figure 10 It is a distribution diagram of the positive - sequence current fault component of the main line of fault 2 provided by an embodiment of the present invention;

[0051] Figure 11 It is a distribution diagram of the positive - sequence current fault component of the branch line of fault 2 provided by an embodiment of the present invention;

[0052] In the figure: 1. Fault location start module; 2. Fault type judgment module; 3. Two - phase short - circuit fault section location module; 4. Three - phase short - circuit fault section location module. Detailed implementation manners

[0053] To make the above - mentioned objects, features and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific implementations disclosed below.

[0054] I. Explanation of the embodiment:

[0055] An embodiment of the present invention provides a method for locating short - circuit fault sections in an oil - field distribution network based on the line - voltage amplitude on the load side. By using the measurement terminals on the load side of the oil field, the line - voltage amplitudes of each measurement node on the load side of the system before and after the short - circuit fault are measured. Based on the characteristics of the line - voltage amplitudes of the measurement nodes on the load side before and after the fault, the fault type and fault phase are determined. According to the fault - phase selection result, in the case of a two - phase short - circuit, combined with the network topology, line parameters, and the line - voltage amplitudes of each measurement node on the load side, the magnitude of the positive - sequence current fault component on the medium - voltage side is calculated. Based on the fact that the magnitude of the positive - sequence current fault component upstream of the fault point is much larger than that downstream of the fault point and the distribution law of the branch lines, a fault - section location criterion is formed to determine the short - circuit fault section of the distribution network. In the case of a three - phase short - circuit, the line - voltage amplitudes of different measurement nodes on the load side are compared horizontally. Based on the distribution law that the line - voltage amplitudes of the measurement nodes on the load side from the power source point to the fault point decrease monotonically, a fault - section location criterion is formed to determine the short - circuit fault section of the distribution network. The present invention only needs to use the existing load - side monitoring terminals in the oil field to measure the line - voltage amplitudes on the load side, does not need to measure the phase, and does not need to add additional monitoring facilities. It can effectively judge the short - circuit fault type and locate the fault occurrence position to the section between two adjacent measurement nodes on the load side.

[0056] Embodiment 1

[0057] As Figure 1 shown, the method for locating short - circuit fault sections in an oil - field distribution network based on the line - voltage amplitude on the load side provided by the embodiment of the present invention includes the following steps:

[0058] S101, based on the distribution characteristics of the line - voltage amplitude on the load side after a short - circuit fault occurs on the medium - voltage side, use the line - voltage amplitudes of the measurement nodes on the load side to judge the fault type and fault phase;

[0059] S102, according to the fault - phase selection result, when a two - phase short - circuit occurs, use the line - voltage amplitudes of the measurement nodes on the load side to calculate the positive - sequence current fault component on the medium - voltage side;

[0060] S103, when a two - phase short - circuit occurs, determine the fault - occurring section according to the distribution characteristics of the calculated positive - sequence current fault component on the medium - voltage side to achieve fault location;

[0061] S104, according to the fault - phase selection result, when a three - phase short - circuit occurs, horizontally compare the difference in line - voltage amplitudes between adjacent measurement nodes on the load side, and determine the fault - occurring section according to the distribution characteristics of the difference in line - voltage amplitudes between adjacent measurement nodes on the load side to achieve fault location.

[0062] Embodiment 2

[0063] Based on the oilfield distribution network short-circuit fault section location method based on the load-side line voltage amplitude provided in Embodiment 1, in a preferred embodiment, the difference from Embodiment 1 is that in step S101, when the load-side monitoring terminal data meets the start criterion, if the magnitudes of the three line voltages at any load-side measurement node i are equal, it is determined that a three-phase short-circuit fault has occurred in the system; if the magnitude of the AB-phase line voltage at any load-side measurement node i remains unchanged before and after the fault, it is determined that a BC two-phase short-circuit fault has occurred in the system; if the magnitude of the BC-phase line voltage at any load-side measurement node i remains unchanged before and after the fault, it is determined that a BC two-phase short-circuit fault has occurred in the system; if the magnitude of the CA-phase line voltage at any load-side measurement node i remains unchanged before and after the fault, it is determined that an AB two-phase short-circuit fault has occurred in the system.

[0064] Embodiment 3

[0065] Based on the oilfield distribution network short-circuit fault section location method based on the load-side line voltage amplitude provided in Embodiment 1, in a preferred embodiment, the difference from Embodiment 1 is that in step S102, when a two-phase short-circuit fault occurs, the three line voltages at any load-side measurement node i in the system are only related to the three-phase voltages on the medium-voltage side of this node before the fault the transformation ratio n of the transformer, and the voltage generated by the positive-sequence current fault component at this node related, where can be obtained from the unchanged line voltage among the three line voltage amplitudes at the load-side measurement node i. The transformer transformation ratio n is known. Therefore, for any load-side measurement node, the magnitudes and phases of can be solved according to the two changed line voltage amplitudes among the three line voltage amplitudes. The positive-sequence current fault component between each section can be obtained by subtracting the corresponding of any two adjacent load-side measurement nodes and dividing by the line impedance between these two nodes;

[0066] Embodiment 4

[0067] Based on the oilfield distribution network short-circuit fault section location method based on the load-side line voltage amplitude provided in Embodiment 1, as a preferred embodiment, the difference from Embodiment 1 is that in step S103, the positive-sequence current fault component between the power supply point and the fault point is much larger than the positive-sequence current fault component downstream of the fault point. If there are no branch lines in the system, among all the sections with a positive-sequence current fault component less than 10% of the positive-sequence current fault component of the line head section, the upstream section of the section closest to the power supply point is the fault occurrence location. If there is no section that meets the conditions and the positive-sequence current fault component of the line end section is less than the upstream section, the line end section is the fault occurrence section; if there are branch lines in the system, the non-branch line location criterion is applied to the main line to judge the fault occurrence location. If there are no branch lines downstream of this fault section, this section is located as the fault occurrence section. If there are branch lines downstream of this fault section, starting from the power supply point and ending at the end node of this branch line, the non-branch line location criterion is applied to judge the fault occurrence location. If it is judged that the fault occurrence section is the same as the main line, this section is located as the fault occurrence section. If it is judged that there are still branch lines downstream of the fault occurrence section, this process is repeated until there are no branch lines downstream of the located section.

[0068] Embodiment 5

[0069] Based on the oilfield distribution network short-circuit fault section location method based on the load-side line voltage amplitude provided in Embodiment 1, as a preferred embodiment, the difference from Embodiment 1 is that in step S104, during a three-phase short circuit, the load-side line voltage amplitude monotonically decreases from the power supply point to the fault point. Based on this distribution law, using any line voltage at each load-side measurement node and considering the voltage drop caused by the load current, the three-phase short-circuit location criterion is determined as follows: calculate the absolute value of the difference between the line voltage amplitudes at adjacent load-side measurement nodes. Among all the sections where the branch lines first appear less than the set value, the upstream section of the section farthest from the power supply point is the fault occurrence section.

[0070] Embodiment 6

[0071] As Figure 2 shown, the oilfield distribution network short-circuit fault section location system based on the load-side line voltage amplitude provided by the embodiment of the present invention includes:

[0072] A fault location start module 1, configured to record the load-side line voltage amplitude and start the fault location process when the sudden change in the line voltage is greater than the set value;

[0073] A fault type judgment module 2, configured to judge the fault type by using the line voltage amplitudes before and after the fault and judge the fault phase when a two-phase short-circuit fault occurs in the system;

[0074] The two-phase short-circuit fault section location module 3 is used to calculate the positive-sequence current fault component of the medium voltage side by using the line voltage on the load side, and determine the section where the two-phase short-circuit fault occurs based on the distribution characteristics of the positive-sequence current fault component of the medium voltage side;

[0075] The three-phase short-circuit fault section location module 4 is used to make a horizontal comparison by using the difference in line voltage amplitudes of adjacent nodes on the load side, and determine the section where the three-phase short-circuit fault occurs based on the distribution characteristics of the line voltage amplitude difference on the load side.

[0076] Embodiment 7

[0077] Another embodiment of the present invention provides a method for locating short-circuit fault sections in an oilfield distribution network based on the line voltage amplitude on the load side. The following functions are realized by programming and empowering the monitoring terminal on the load side: retain the line voltage data read within one minute. When a fault occurs in the system, use the sudden change in line voltage as the starting criterion, and use the moment when the sudden change in line voltage is greater than 0.1U N as the fault moment. At the same time, read two cycles at T1 moment after the fault moment and T2 moment before the fault moment as the calculation data for fault phase selection and fault location.

[0078] Use the line voltage amplitudes obtained by each monitoring terminal on the load side to judge the short-circuit fault type. If the magnitudes of the three line voltages are equal after the fault at any load-side measurement node i, it is judged that a three-phase short-circuit fault occurs in the system; if the line voltage amplitudes of phases AB at any load-side measurement node i remain unchanged before and after the fault, it is judged that a BC two-phase short-circuit fault occurs in the system; if the line voltage amplitudes of phases BC at any load-side measurement node i remain unchanged before and after the fault, it is judged that a BC two-phase short-circuit fault occurs in the system; if the line voltage amplitudes of phases CA at any load-side measurement node i remain unchanged before and after the fault, it is judged that an AB two-phase short-circuit fault occurs in the system.

[0079] When a three-phase short circuit occurs, the line voltage amplitude on the load side decreases monotonically from the power supply point to the fault point. Based on this distribution law, use any line voltage at each load-side measurement node, considering the voltage drop caused by the load current downstream of the fault point, and determine the three-phase short-circuit location criterion as: calculate the absolute value of the difference between the line voltage amplitudes between adjacent load-side measurement nodes. Among all the branches, the upstream section of the section farthest from the power supply point where the value first appears less than the set value is the section where the fault occurs. Here, considering the load size, the set value is taken as 10V.

[0080] When a two-phase short circuit occurs in the system, here taking the BC two-phase short circuit as an example for analysis, the expression of the line voltage amplitude at any load-side measurement node i is:

[0081]

[0082] When a two-phase short circuit occurs in the system, the three line voltages on the load side at any measurement node i on the load side of the system are only related to the three-phase voltages before the fault on the medium-voltage side of this node the turns ratio n of the transformer, the mutual impedance Z between this node and the fault point if , and the fault current . Among them, the voltage during normal operation of this node can be obtained from the amplitude of the line voltage AB on the load side after the fault. Let the voltage of phase A before the fault obtained be at 0 phase, and then the three-phase voltages before the fault can be obtained based on the voltage of phase A. Since the turns ratio of the transformer is known, regarding the product of the mutual impedance Z if and the fault current as a variable, define this variable as . Therefore, for any measurement node on the load side, taking the amplitude of the line voltage on the load side as the dependent variable, the amplitude and phase of are used as independent variables to generate two equations, and solve the amplitude and phase of two variables respectively. Then, according to the amplitude of the line voltage on the load side, the corresponding of each measurement node on the load side of the system can be obtained.

[0083] Subtracting the corresponding between any two adjacent measurement nodes on the load side is . Its physical meaning is that when the positive-sequence fault current flows into the fault point, it is the voltage difference between these two adjacent measurement nodes on the load side. Define the voltage difference between adjacent measurement nodes m and n on the load side as to obtain the voltage difference between each section . Combining the line topology and line parameters, using divided by the line impedance between m and n can obtain the positive-sequence current fault component between each section.

[0084] If there is no branch line in the system, for the positive-sequence current fault component of the medium-voltage side obtained using the amplitude of the line voltage on the load side, based on the distribution law that the amplitude of the positive-sequence current fault component upstream of the fault point is much larger than that downstream of the fault point, the two-phase short-circuit fault location criterion for the branchless line is: among all the sections with a positive-sequence current fault component less than 10% of the positive-sequence current fault component of the first section at the line head, the upstream section of the section closest to the power source point is the fault occurrence location. If there is no section that meets the conditions and the positive-sequence current fault component of the last section of the line is less than the upstream section, then the last section of the line is the fault occurrence section.

[0085] If there are branch lines in the system, based on the fact that the magnitude of the positive-sequence current fault component on the medium-voltage side obtained from the line voltage magnitude on the load side is much larger than the distribution law of the positive-sequence current fault component downstream of the fault point and that of the branch lines, the two-phase short-circuit fault location criterion for branch lines is determined as follows: First, apply the non-branch line location criterion to the main line to determine the fault location. If there are no branch lines downstream of the fault section, then locate this section as the fault section. If there are branch lines downstream of the fault section, starting from the power supply point and ending at the end node of this branch line, apply the non-branch line location criterion to determine the fault location. If it is determined that the fault section is the same as the main line, then locate this section as the fault section. If it is determined that there are still branch lines downstream of the fault section, repeat this process until there are no branch lines downstream of the located section.

[0086] Embodiment 8

[0087] Another embodiment of the present invention provides a method for locating short-circuit fault sections in an oilfield distribution network based on the line voltage magnitude on the load side. Its location flowchart is as Figure 3 shown, and specifically includes the following steps:

[0088] (1) Fault location start criterion

[0089] The composition of the short-circuit fault location system for the oilfield distribution network is as shown in the appendix Figure 4 shown, including the master station and the load-side monitoring terminal. Upload the data of the oilfield load-side monitoring terminal to the master station. After a short-circuit fault occurs on the medium-voltage side, the system voltage drops rapidly. When the line voltage magnitude at the load-side measurement node drops to 90% of the rated voltage, the fault location process starts, and at the same time, read two cycles at T1 moment after the fault moment and T2 moment before the fault moment as the calculation data for fault phase selection and fault location. The specific implementation process is as shown in the appendix Figure 5 shown.

[0090] (2) Short-circuit fault type judgment

[0091] Use the line voltage magnitudes obtained from each load-side monitoring terminal to judge the short-circuit fault type. If the magnitudes of the three line voltages at any load-side measurement node i are equal after the fault, it is judged that a three-phase short-circuit fault occurs in the system; if the line voltage magnitude of phase AB at any load-side measurement node i remains unchanged before and after the fault, it is judged that a BC two-phase short-circuit fault occurs in the system; if the line voltage magnitude of phase BC at any load-side measurement node i remains unchanged before and after the fault, it is judged that a BC two-phase short-circuit fault occurs in the system; if the line voltage magnitude of phase CA at any load-side measurement node i remains unchanged before and after the fault, it is judged that an AB two-phase short-circuit fault occurs in the system.

[0092] (3) Solve the positive-sequence current fault component on the medium-voltage side during two-phase short circuit

[0093] When a two-phase short circuit occurs in the system, taking the BC two-phase short circuit as an example for analysis here, the expression for the line voltage amplitude at any load-side measurement node i is:

[0094]

[0095] When a two-phase short circuit occurs in the system, the three line voltages on the load side at any load-side measurement node i in the system are only related to the three-phase voltages before the fault on the medium-voltage side of this node the transformation ratio n of the transformer, the mutual impedance Z between this node and the fault point if , and the fault current . Among them, the voltage during normal operation of this node can be obtained from the amplitude of the AB line voltage on the load side after the fault. Let the voltage of phase A before the fault obtained be at 0 phase, then the three-phase voltages before the fault can be obtained according to the voltage of phase A; since the transformation ratio of the transformer is known, regarding the product of the mutual impedance Z if and the fault current as a variable, define this variable as Therefore, for any load-side measurement node, taking the load-side line voltage amplitude as the dependent variable, the amplitude and phase of as the independent variables to generate two equations, and solve the

[0096] amplitude and phase of the two variables of Subtracting the corresponding values of any two adjacent load-side measurement nodes gives Its physical meaning is that when the positive-sequence fault current flows into the fault point, it is the voltage difference between these two adjacent load-side measurement nodes; define the voltage difference between adjacent load-side measurement nodes mn as to obtain the voltage difference between each section Combining the line topology and line parameters, using Dividing by the line impedance between mn can obtain the positive-sequence current fault component between each section.

[0097] (4) Fault location based on the distribution of the obtained positive-sequence current fault components during a two-phase short circuit

[0098] The schematic diagram of a two-phase short circuit fault occurring in a non-branched line is as shown in the appendix Figure 6 .

[0099] Since the voltage of the load-side measurement node n is approximately equal to the voltage at the fault point f, that is Let the calculated value of the positive-sequence current fault component in the mn section be Then: And

[0100] Based on this distribution characteristic, the two-phase short-circuit location criterion for a non-branched line is as follows: among all the sections where the positive-sequence current fault component is less than 10% of the positive-sequence current fault component of the first section at the head of the line, the upstream section of the section closest to the power source point is the fault occurrence location. If there is no section meeting the condition and the positive-sequence current fault component of the last section of the line is less than that of the upstream section, then the last section of the line is the fault occurrence section.

[0101] The schematic diagram of a two-phase short-circuit fault occurring in a branched line is shown in the appendix Figure 7 as follows.

[0102] According to the fault location analysis for a non-branched line, the positive-sequence current fault component of each section can be obtained based on the line voltage amplitude on the load side. Among them,

[0103] Based on this distribution characteristic, the two-phase short-circuit location criterion for a branched line is as follows: First, apply the non-branched line location criterion to the main line to determine the fault occurrence location. If there is no branch downstream of the fault section, then locate this section as the fault occurrence section. If there is a branch downstream of the fault section, starting from the power source point and ending at the terminal node of this branch, apply the non-branched line location criterion to determine the fault occurrence location. If the determined fault occurrence section is the same as that of the main line, then locate this section as the fault occurrence section. If there is still a branch downstream of the determined fault occurrence section, repeat this process until there is no branch downstream of the located section.

[0104] (5) Fault location based on the distribution of line voltage amplitude on the load side during a three-phase short circuit

[0105] During a three-phase short circuit, the line voltage amplitude on the load side monotonically decreases from the power source point to the fault point. Based on this distribution law, using any line voltage at each load-side measurement node, considering the voltage drop caused by the load current downstream of the fault point, the three-phase short-circuit location criterion is determined as follows: Calculate the absolute value of the difference between the line voltage amplitudes between adjacent load-side measurement nodes. Among all the sections where the line voltage amplitude first appears less than the set value, the upstream section of the section farthest from the power source point is the fault occurrence section. Here, considering the load size, the set value is taken as 10V.

[0106] In the above embodiments, the descriptions of each embodiment have their own focuses. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0107] Regarding the information interaction, execution process, etc. between the above-mentioned devices / units, since they are based on the same concept as the method embodiment of the present invention, for their specific functions and the technical effects brought, reference can be specifically made to the method embodiment part, and details are not described here again.

[0108] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiments can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of the present invention. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0109] II. Application Embodiments:

[0110] Application Example 1

[0111] The application embodiments of the present invention further provide a computer device, which includes: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor. When the processor executes the computer program, the steps in any of the foregoing method embodiments are implemented.

[0112] Application Example 2

[0113] The application embodiments of the present invention further provide a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps in the foregoing method embodiments can be implemented.

[0114] Application Example 3

[0115] The application embodiments of the present invention further provide an information data processing terminal, which is used to provide a user input interface to implement the steps in the foregoing method embodiments when executed on an electronic device. The information data processing terminal is not limited to mobile phones, computers, and switches.

[0116] Application Example 4

[0117] The application embodiments of the present invention further provide a server, which is used to provide a user input interface to implement the steps in the foregoing method embodiments when executed on an electronic device.

[0118] Application Example 5

[0119] An application embodiment of the present invention provides a computer program product. When the computer program product runs on an electronic device, the electronic device can execute the steps in the above-mentioned method embodiments when executed.

[0120] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-mentioned method embodiments of the present invention, a computer program can be used to instruct relevant hardware to complete. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc. The computer-readable medium can at least include: any entity or device that can carry the computer program code to the photographing device / terminal device, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disc, etc.

[0121] III. Evidence of related effects of the embodiment:

[0122] Build a simulation model of a certain 20-node oilfield distribution network as shown in the appendix in PSCAD. The line parameters and node load parameters are shown in Table 1 and Table 2: Figure 8 As shown:

[0123] Table 1 Line parameters of the 20-node oilfield distribution network simulation example

[0124]

[0125] Table 2 Node load parameters of the 20-node oilfield distribution network

[0126]

[0127] When the short-circuit fault transition resistance is set to 0Ω, 2Ω, and 5Ω respectively, simulate a fault 1 occurring between nodes 05-06. Here, the line end node is selected as the fault phase selection criterion. Among the line voltage amplitudes monitored by the load side monitoring terminal at the line end node under different transition resistances, the AB line voltage amplitude remains unchanged before and after the fault. Therefore, it is judged that the fault type is a BC two-phase short-circuit fault.

[0128] Using the three line voltages of the load side detection node, calculate the positive sequence current fault component of the medium voltage side main line under different transition resistances as shown in the appendix Figure 9as shown

[0129] Applying the two-phase short-circuit fault location criterion to the positive-sequence current fault component of the medium-voltage side main line, it can be known that the fault occurs at nodes 05-06. There are no branch lines downstream of nodes 05-06. Therefore, the fault location result is that a BC two-phase short-circuit fault occurs between nodes 05-06, which is the same as the set fault type and fault location, and the location result is accurate.

[0130] When the system load rates are set to 10%, 20%, 50%, 80%, and 100% respectively, a fault 2 occurs between nodes 0502-0503. Here, the line end node is selected as the fault phase selection criterion. Among the line voltage amplitudes obtained by the monitoring terminal on the load side of the line end node under different load rates, the AB line voltage amplitude remains unchanged before and after the fault. Therefore, the fault type is judged to be a BC two-phase short-circuit fault.

[0131] Using the three line voltages of the load side detection node, the positive-sequence current fault component of the medium-voltage side main line under different transition resistances is calculated as shown in the appendix Figure 10 as shown

[0132] Applying the two-phase short-circuit fault location criterion to the positive-sequence current fault component of the medium-voltage side main line, it can be known that the fault occurs at nodes 04-05. There are branch lines downstream of nodes 04-05. Then, starting from the line start node and ending at node 0504, the non-branched line location criterion is applied. The positive-sequence current fault component of the medium-voltage side is as shown Figure 11 as shown. From Figure 11 it can be known that the fault occurs between nodes 0502-0503. There are no branch lines downstream of nodes 0502-0503. Therefore, the fault location result is that a BC two-phase short-circuit fault occurs between nodes 0502-0503, which is the same as the set fault type and fault location, and the location result is accurate.

[0133] When the system transition resistances are set to 0Ω, 2Ω, and 5Ω respectively, a fault 3 occurs between nodes 06-07. Here, the line end node is selected as the fault phase selection criterion. Under different transition resistances, the three line voltage amplitudes obtained by the monitoring terminal on the load side of the line end node are the same. Therefore, the fault type is judged to be a three-phase short-circuit fault. Therefore, any line voltage amplitude is selected as the fault location data. The absolute values of the differences in line voltage amplitudes between adjacent load side measurement nodes under different transition resistances are shown in Table 3. From Table 3, it can be seen that the sections where each branch line first appears less than the set value of 10V are: 07-08, 02-0201, 03-0301, 05-0501. Among them, the section farthest from the power source point is the 07-08 section. Then, the short-circuit fault occurs in the section upstream of the 07-08 section, that is, between nodes 06-07, and the fault type is a three-phase short-circuit fault, which is the same as the set fault type and fault location, and the location result is accurate.

[0134] Absolute value of difference in line voltage amplitudes of adjacent load-side measurement nodes in Table 3

[0135]

[0136]

[0137] As described above, it is only a preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for locating short - circuit fault sections in an oil - field distribution network based on the amplitude of the line voltage on the load side, characterized in that, The method includes the following steps: S1. Based on the distribution characteristics of the load-side line voltage amplitude after a short-circuit fault occurs on the medium-voltage side, use the line voltage amplitude of the load-side measurement nodes to judge the fault type and the faulty phase; S2. According to the fault phase selection result, in the case of a two-phase short circuit, use the line voltage amplitude of the load-side measurement nodes to calculate the positive-sequence current fault component on the medium-voltage side; based on the distribution characteristics of the calculated positive-sequence current fault component on the medium-voltage side, determine the fault occurrence section to achieve fault location; S3. According to the fault phase selection result, in the case of a three-phase short circuit, horizontally compare the difference in line voltage amplitude between adjacent load-side measurement nodes, and based on the distribution characteristics of the difference in line voltage amplitude between adjacent load-side measurement nodes, determine the fault occurrence section to achieve fault location; In step S1, when the data of the load-side monitoring terminal meets the start criterion, if the magnitudes of the three line voltages at any load-side measurement node i are equal, it is judged that a three-phase short-circuit fault occurs in the system; if the line voltage amplitude of phase AB at any load-side measurement node i remains unchanged before and after the fault, it is judged that a BC two-phase short-circuit fault occurs in the system; if the line voltage amplitude of phase BC at any load-side measurement node i remains unchanged before and after the fault, it is judged that a BC two-phase short-circuit fault occurs in the system; if the line voltage amplitude of phase CA at any load-side measurement node i remains unchanged before and after the fault, it is judged that an AB two-phase short-circuit fault occurs in the system; When a BC two-phase short circuit occurs, the expression of the line voltage amplitude at any load-side measurement node i of BC is as follows: Among them, any load-side measurement node is i, and the three-phase voltages on the medium-voltage side of the node before the fault are respectively The turns ratio of the transformer is n, and the mutual impedance between the node and the fault point is Z if , and the fault current is The voltage of this node during normal operation is obtained from the amplitude of the line voltage of phase AB on the load side after the fault. Let the pre-fault phase A voltage obtained be at 0 phase, and the pre-fault three-phase voltages are obtained based on the phase A voltage; the turns ratio of the transformer is known, and the mutual impedance Z if and the fault current product is regarded as a variable, and this variable is defined as For any load-side measurement node, using the load-side line voltage amplitude as the dependent variable, generate two equations with the amplitude and phase of as the independent variables, and solve for the two variables of the amplitude and phase. Then, based on the load-side line voltage amplitude, the corresponding to each load-side measurement node of the system can be obtained. The difference between the corresponding to any two adjacent load-side measurement nodes is the positive-sequence fault current flowing into the fault point. When this occurs, it is the voltage difference between these two adjacent load-side measurement nodes; define the voltage difference between adjacent load-side measurement nodes mn as to obtain the voltage difference between each section. Combined with the line topology and line parameters, use divided by the line impedance between mn to obtain the positive-sequence current fault component between each section.

2. The method for locating the short - circuit fault section of the oil - field distribution network based on the load - side line - voltage amplitude according to claim 1, wherein, In step S2, when a two-phase short circuit occurs, in the process of determining the fault section where the fault occurs based on the distribution characteristics of the positive-sequence current fault component on the medium-voltage side to achieve fault location, the voltage of the load-side measurement node n is equal to the voltage at the fault point f. Let the calculated value of the positive-sequence current fault component in the mn section be Then: And Based on this distribution characteristic, the two-phase short-circuit location criterion for a non-branched line is: among all sections with a positive-sequence current fault component less than 10% of that of the first section of the line, the upstream section of the section closest to the power source is the fault location. If there is no section meeting the condition and the positive-sequence current fault component of the last section of the line is less than that of the upstream section, then the last section of the line is the fault section. According to the fault location analysis in the case of a non-branched line, the positive-sequence current fault component of each section can be obtained based on the line voltage amplitude on the load side, where Based on this distribution characteristic, the two-phase short-circuit location criterion when there is a branch line is: first, apply the non-branch line location criterion to the main line to judge the fault occurrence location. If there is no branch line downstream of this fault section, then locate this section as the fault occurrence section. If there is a branch line downstream of this fault section, then starting from the power source point and ending at the terminal node of this branch line, apply the non-branch line location criterion to judge the fault occurrence location. If it is judged that the fault occurrence section is the same as the main line, then locate this section as the fault occurrence section. If it is judged that there is still a branch line downstream of the fault occurrence section, then repeat this process until there is no branch line downstream of the located section.

3. The oilfield distribution network short-circuit fault section location method based on the load-side line voltage amplitude according to claim 1, characterized in that In step S3, during a three-phase short circuit, the load-side line voltage amplitude decreases monotonically from the power source point to the fault point. Based on this distribution law, use any line voltage at each load-side measurement node, considering the voltage drop caused by the load current, to determine the three-phase short-circuit location criterion: calculate the absolute value of the difference between the line voltage amplitudes at adjacent load-side measurement nodes. Among all the sections where the value first becomes less than the set value for the branch lines, the section upstream of the section farthest from the power source point is the fault occurrence section.

4. An oilfield distribution network short - circuit fault section location system based on the load - side line voltage amplitude for implementing the oilfield distribution network short - circuit fault section location method based on the load - side line voltage amplitude according to any one of claims 1 to 3, characterized in that, The oilfield distribution network short-circuit fault section location system based on the load-side line voltage amplitude includes: A fault location start module (1), which is used to record the load-side line voltage amplitude and start the fault location process when the sudden change in the line voltage is greater than the set value; A fault type judgment module (2), which is used to judge the fault type by using the line voltage amplitude before and after the fault, and judge the faulty phase when a two-phase short-circuit fault occurs in the system; The two-phase short-circuit fault section location module (3) is used to calculate the positive-sequence current fault component of the medium voltage side by using the line voltage on the load side, and determine the section where the two-phase short-circuit fault occurs based on the distribution characteristics of the positive-sequence current fault component of the medium voltage side; The three-phase short-circuit fault section location module (4) is used to make a horizontal comparison of the line voltage amplitude differences of adjacent nodes on the load side, and determine the section where the three-phase short-circuit fault occurs based on the distribution characteristics of the line voltage amplitude differences on the load side.

5. The oilfield distribution network short-circuit fault section location system based on the load-side line voltage amplitude according to claim 4, characterized in that, The oilfield distribution network short-circuit fault section location system based on the line voltage amplitude on the load side further includes a master station and a load-side monitoring terminal; The load-side monitoring terminal uploads the data of the fault type and fault phase determined based on the line voltage amplitude characteristics of the load-side measurement nodes before and after the fault to the master station. After a short-circuit fault occurs on the medium voltage side, the system voltage drops. When the line voltage amplitude of the load-side measurement node drops to 90% of the rated voltage, the fault location process starts, and at the same time, two cycles at time T1 after the fault moment and time T2 before the fault moment are read as the calculation data for fault phase selection and fault location.

6. A computer device, characterized in that, The computer device includes a memory and a processor. When the computer program stored in the memory is executed by the processor, the processor executes the oilfield distribution network short-circuit fault section location method based on the line voltage amplitude on the load side according to any one of claims 1 to 3.

7. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, the processor executes the oilfield distribution network short-circuit fault section location method based on the line voltage amplitude on the load side according to any one of claims 1 to 3.

8. A feeder terminal device for locating short - circuit fault sections in an oil - field distribution network, characterized in that, When the feeder terminal device is used to be implemented on an electronic device, a user input interface is provided to implement the oilfield distribution network short-circuit fault section location method based on the line voltage amplitude on the load side according to any one of claims 1 to 3.

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