Typical fault simulation test platform and test method for real-type power distribution network in low-voltage transformer area

Abstract

The invention discloses a typical fault simulation test platform for a real-type power distribution network of a low-voltage transformer area, as shown in Figure 1, comprising a low-voltage transformer area simulation structure which is connected with a transformer area fusion terminal in a wireless mode. The low-voltage transformer area simulation structure is further connected with a low-voltage fault simulation device and low-voltage intelligent equipment through wiring terminals in a circuit, and the low-voltage fault simulation device and the low-voltage intelligent equipment are connected with the low-voltage transformer area simulation structure in a wireless mode. The low-voltage intelligent device is also connected with the low-voltage fault simulation device and the transformer area fusion terminal in a wireless mode. The invention also discloses a method for testing by using the typical fault simulation test platform for the real-type power distribution network of the low-voltage transformer area. According to the typical fault simulation test platform for the real-type power distribution network in the low-voltage transformer area, the running state of the power distribution network in the low-voltage transformer area can be truly simulated, various typical faults of the low-voltage power distribution network can be reproduced, and the problem that an existing test platform cannot achieve a real test effect is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical equipment, and specifically relates to a typical fault simulation test platform for a real distribution network in a low-voltage area, and also relates to a method for performing fault simulation using the above simulation test platform. Background Art

[0002] As an important part of the power grid, the distribution network is an important infrastructure for the supply of electric energy and bears important economic and social responsibilities in the national economy and social life. As the "last mile" of power supply services, the low-voltage distribution network directly faces users and has the characteristics of multiple points, wide coverage and complex structure. With the rapid increase in the number of equipment connected to the low-voltage area, higher requirements are placed on the smooth operation and fault recovery of the area, which brings more risks and challenges to the operation of the low-voltage distribution network.

[0003] At present, the existing distribution network real test platform mainly faces the following problems:

[0004] (1) In terms of low-voltage distribution networks, most experiments and research are carried out by building a real environment or using software simulation, and most of them are about building the physical environment of the low-voltage substation itself, but not much about reproducing complex fault scenarios.

[0005] (2) At present, domestic and foreign universities and provincial power grid companies have established a variety of real-type test platforms, but they are mainly concentrated in the real-type test platform of the medium-voltage distribution network. An integrated detection platform for multi-power distribution automation terminals including physical simulation and digital simulation has been built, but it cannot cover all distribution network equipment, and the detection equipment is relatively single. According to the actual use environment, the on-site distribution network pole switch equipment and its controller were installed to simulate the real overhead distribution system, but because a simulation system was used, the effect of the real test could not be achieved.

[0006] (3) Since each substation needs to simulate a different number of users, different substation topologies, different faults, and different test points, ordinary simulation devices are limited by the simulation units and cannot expand the simulation hardware indefinitely. They cannot meet the needs of various combination environments such as a large number of users, multiple branch forms, and multiple topological forms in different types of substations. They can only directly simulate faults on the limited units of the simulation device and can only simulate the features within the limited functions of the device, which simplifies the complex environment and troubleshooting of the substation. They cannot truly reflect the characteristics of the substation or the true characteristics of the entire substation, and thus cannot experience the closed-loop process of fault analysis, troubleshooting, verification, and governance and recovery in the substation. Summary of the invention

[0007] The purpose of the present invention is to provide a low-voltage distribution network typical fault simulation test platform, which can truly simulate the operating status of the low-voltage distribution network and reproduce a variety of typical faults of the low-voltage distribution network, thus solving the problem that the existing test platform cannot achieve real test effects.

[0008] Another object of the present invention is to provide a method for performing fault simulation using the above-mentioned simulation test platform.

[0009] The first technical solution adopted by the present invention is a typical fault simulation test platform for a real distribution network in a low-voltage substation, including a low-voltage substation simulation structure. The low-voltage substation simulation structure is connected to a substation fusion terminal through a wireless connection. The low-voltage substation simulation structure is also connected to a low-voltage fault simulation device and a low-voltage intelligent device through wiring terminals in the line. The low-voltage fault simulation device and the low-voltage intelligent device are also connected to the low-voltage substation simulation structure through a wireless connection. The low-voltage intelligent device is also connected to the low-voltage fault simulation device and the substation fusion terminal through a wireless connection.

[0010] The present invention is also characterized in that:

[0011] The low-voltage substation simulation structure includes a first substation and a second substation. The first substation includes a first distribution transformer side, the first distribution transformer side is connected to the first low-voltage side through a low-voltage bus, the first low-voltage side is connected to the first line side through the low-voltage bus, and the first line side is connected to the first user side through the low-voltage bus; the second substation includes a second distribution transformer side, the second distribution transformer side is connected to the second low-voltage side through the low-voltage bus, the second low-voltage side is connected to the second line side through the low-voltage bus, and the second line side is connected to the second user side through the low-voltage bus;

[0012] The substation fusion terminal is connected to the first distribution transformer side and the second distribution transformer side respectively through RS485 or micro-power wireless communication, the substation fusion terminal is connected to the first low-voltage side and the second low-voltage side respectively through RS485, remote signaling or micro-power wireless communication, the substation fusion terminal is connected to the first line side and the second line side respectively through micro-power wireless or HPLC communication, and the substation fusion terminal is connected to the first user side and the second user side respectively through HPLC communication or by adding a communication conversion unit.

[0013] The first distribution transformer side includes a first distribution isolation transformer, the low-voltage side of the first distribution isolation transformer is connected to the low-voltage busbar at the power output end through a low-voltage intelligent leakage protection switch, and also includes a first intelligent environmental sensor, and a low-voltage outgoing line on the low-voltage busbar is connected to the first intelligent environmental sensor through a low-voltage intelligent switch and then connected to the line side;

[0014] The first low-voltage side includes a first area master meter, a first multi-function meter, a first phase-changing switch relay and a first reactive power compensation device, wherein the first area master meter, the first multi-function meter, the first phase-changing switch relay and the first reactive power compensation device are arranged in parallel and are respectively connected through the low-voltage outlet line of the low-voltage busbar;

[0015] The first line side includes branch box No. 1 and branch box No. 2, branch box No. 1 includes a first low-voltage intelligent switch, the first low-voltage intelligent switch is electrically connected to two second low-voltage intelligent switches, the low-voltage outlet line of one of the second low-voltage intelligent switches is electrically connected to three parallel first intelligent phase-changing switches, the three first intelligent phase-changing switches are electrically connected to a first single-phase meter, each first single-phase meter is provided with a first intelligent micro-break switch on the wire connected to the first intelligent phase-changing switch, the three first single-phase meters are commonly connected to a first single-phase simulated RLC load, the low-voltage outlet line of another second low-voltage intelligent switch is electrically connected to two second intelligent phase-changing switches, the two second intelligent phase-changing switches are electrically connected to three second intelligent micro-break switches, each second intelligent micro-break switch is electrically connected to a second single-phase meter, the output ends of the six second single-phase meters are respectively connected to terminals, and also includes a first three-phase simulated RLC load, the first three-phase simulated RLC load can be connected to the three second single-phase meters connected to the output end of any second intelligent phase-changing switch through terminals;

[0016] Branch box No. 2 includes a third low-voltage intelligent switch, the third low-voltage intelligent switch is electrically connected to two fourth low-voltage intelligent switches, one of the fourth low-voltage intelligent switches is connected to a terminal at its output end, and the other fourth low-voltage intelligent switch is electrically connected to three third intelligent micro-break switches, each of which is electrically connected to a first three-phase meter, each of which is electrically connected to a first RCD load, a first photovoltaic inverter and a terminal, and the first photovoltaic inverter is electrically connected to a photovoltaic simulation power supply;

[0017] The first station area also includes a first fault simulation device and a second abnormal operation simulation device, and the first fault simulation device and the second abnormal operation simulation device can be connected to corresponding terminals as needed;

[0018] All access devices are equipped with busbar connection and are compatible with external device access. All access devices are replaceable. Remote control switches are integrated before and after the busbar and connected to fault simulation devices to simulate line short circuit, open circuit and other faults.

[0019] The second distribution transformer side includes a second distribution isolation transformer, the low-voltage side of the second distribution isolation transformer is connected to the low-voltage busbar at the power output end through a low-voltage intelligent leakage protection switch, and also includes a second intelligent environmental sensor, and a low-voltage outgoing line on the low-voltage busbar is connected to the line side after being connected to the second intelligent environmental sensor through a low-voltage intelligent switch;

[0020] The second low-voltage side includes a second area master meter, a second multi-function meter, a second phase-changing switch relay, and a second reactive power compensation device, which are arranged in parallel and are respectively connected to the low-voltage outgoing line of the low-voltage busbar;

[0021] The second line side includes branch box No. 3 and branch box No. 4, branch box No. 3 includes a first low-voltage molded case switch, the first low-voltage molded case switch is electrically connected to a first LTU, the first LTU is electrically connected to two second low-voltage molded case switches, the two second low-voltage molded case switches are electrically connected to a second LTU, one of the second LTU output ends is connected to a terminal, the other second LTU is electrically connected to two third intelligent phase-changing switches, each of the third intelligent phase-changing switches is electrically connected to three fourth intelligent micro-break switches, each of the fourth intelligent micro-break switches is electrically connected to a third single-phase meter, the output ends of the six third single-phase meters are connected to terminals, and also includes a second three-phase simulated RLC load, the second three-phase simulated RLC load can be connected to the three third single-phase meters connected to the output end of any third intelligent phase-changing switch through the terminal;

[0022] Branch box No. 4 includes a third low-voltage molded case switch, which is electrically connected to a third LTU, and the third LTU is electrically connected to two fourth low-voltage molded case switches, and the two fourth low-voltage molded case switches are electrically connected to a fourth LTU, one of the fourth LTUs is electrically connected to three fifth intelligent micro-break switches, and each fifth intelligent micro-break switch is electrically connected to a second three-phase meter, and the three second three-phase meters are respectively connected to a second RCD load, load equipment and terminals, and another fourth LTU is electrically connected to three fourth intelligent phase-changing switches, and each fourth intelligent phase-changing switch is electrically connected to a sixth intelligent micro-break switch, and each sixth intelligent micro-break switch is electrically connected to a fourth single-phase meter, and the three fourth single-phase meters are electrically connected to a second single-phase simulated RLC load.

[0023] The second station area also includes a second fault simulation device and a second abnormal operation simulation device, and the second fault simulation device and the second abnormal operation simulation device can be connected to corresponding terminals as needed;

[0024] The second substation is equipped with LTU equipment on the low-voltage molded case switch. All access devices are equipped with busbar connections and are compatible with external device access.

[0025] The first substation can switch between the TT system and the TNS system. A low-voltage outgoing line on the low-voltage side of the substation's power distribution isolation transformer is connected to the PE line. When the PE line is closed, the system is a three-phase five-wire TN-S system. At this time, the user equipment shell is grounded to the PE line; when the PE line is open, the system is a three-phase four-wire TT system, and the user equipment shell is grounded using independent direct grounding.

[0026] The second area can switch between the TNC and TNC-S systems through a remote switch. There is no PE line at the front end of the area. A low-voltage outgoing line on the low-voltage side of the distribution isolation transformer in the area is connected to the PE line. The system can be adjusted to two types:

[0027] Three-phase four-wire TN-C system: The user equipment shell is grounded using a common PEN line;

[0028] Three-phase four-wire TN-CS system: The user equipment casing is grounded partially by a common PEN wire and partially by a PE wire.

[0029] The second technical solution adopted by the present invention is a method for performing a fault simulation test using the above-mentioned low-voltage distribution network typical fault simulation test platform, and the specific steps are as follows:

[0030] S1. Connect the low-voltage fault simulation equipment in the general environment of low-voltage real-type test, and connect the equipment to be tested through the distribution network equipment access device;

[0031] S2. Adjust the adjustable load according to the test requirements;

[0032] S3. Conduct fault simulation experiment operation;

[0033] S4. Test the state change of the device under test when a fault occurs to verify the quality of the device under test.

[0034] The present invention is also characterized in that:

[0035] S2 is specifically:

[0036] The adjustable load can change the load type according to the fault form requirements. The adjustable load includes resistive load, capacitive load and inductive load, all of which are independently adjustable;

[0037] By controlling the thyristor control time and increasing the resistance to increase the current, the unbalanced three-phase current and instantaneous high current in the substation can be simulated.

[0038] Through the residual current test device, any phase residual current can occur, including normal residual current and fault residual current;

[0039] Remote control switches are integrated on the connection busbars of all access devices on the distribution transformer side, low voltage side, line side, and user side to achieve line switching and fault point access;

[0040] The harmonic generating device can be used to simulate the fault of voltage and current distortion, and the recording device can be used to record the waveform.

[0041] The specific method of S3 is: the low-voltage substation simulation structure sends fault preset instructions to the low-voltage fault simulation device and low-voltage intelligent equipment, or directly simulates the real fault through the low-voltage fault simulation device. After the low-voltage intelligent device senses the fault, it sends it to the substation fusion terminal. At the same time, the substation fusion terminal itself can also sense the fault information, and the back-end area fusion terminal sends the real-time alarm information to the low-voltage fault simulation test platform. The specific alarm information can be viewed through the platform large screen to carry out fault troubleshooting.

[0042] S3 low voltage fault simulation includes the following:

[0043] The low-voltage fault simulation device is used to simulate various complex working conditions of the low-voltage distribution network, as well as single-phase grounding faults and high-current faults of the low-voltage distribution network;

[0044] Various complex working conditions of low-voltage distribution networks include three-phase imbalance, overvoltage, harmonic generation, topology changes, distributed power access, power theft, and line loss;

[0045] Single-phase grounding faults in low-voltage distribution networks include high-resistance grounding faults, low-resistance grounding faults, metallic grounding faults, arc grounding faults or intermittent grounding faults;

[0046] High current faults include phase-to-phase short circuit and three-phase short circuit.

[0047] The beneficial effects of the present invention are:

[0048] (1) The simulation test platform of the present invention is based on real-type tests, combined with simulation modeling, and comprehensively considers the structural diversity, fault complexity and system-level testing requirements of the low-voltage distribution network in Shaanxi Province. It builds a general environment for low-voltage real-type tests, which can simulate typical faults in low-voltage areas, provide a real-type test environment for solving actual problems on the distribution network site, and promote the development of comprehensive perception and intelligent control of low-voltage distribution networks;

[0049] (2) The simulation test platform of the present invention constructs a typical fault simulation test platform for a real distribution network in a low-voltage area and introduces fault simulation and complex working condition scene reproduction equipment into the system to achieve a comprehensive simulation of the operation of a typical low-voltage area, providing an effective means for equipment function performance, algorithm research, and communication protocol verification;

[0050] (3) The simulation test platform of the present invention aims at some scenarios that cannot be realized through physical simulation, or the simulation scenario is single. The present invention cooperates with the cloud master station, the intelligent fusion terminal of the substation area, and the intelligent IoT terminal through digital simulation and real-type test, and conducts data interaction to carry out semi-physical simulation. Through digital simulation, the existing hardware system is expanded to achieve more complex scenario simulation and solve the problem of equipment limitations. Through the self-developed injection test software and test system, the actual needs of the site and the system-level testing problems are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a structural block diagram of a typical fault simulation test platform for a real distribution network in a low-voltage area of ​​the present invention;

[0052] Figure 2 This is a system functional structure diagram of a typical fault simulation test platform for a real distribution network in a low-voltage area of ​​the present invention;

[0053] Figure 3 It is a line structure diagram of the first substation of the low-voltage substation real distribution network typical fault simulation test platform of the present invention;

[0054] Figure 4 It is a circuit structure diagram of the second substation of the low-voltage substation area real distribution network typical fault simulation test platform of the present invention;

[0055] Figure 5 It is a schematic diagram of the occurrence of faults in Example 1 of a typical fault simulation test platform for a real distribution network in a low-voltage substation of the present invention.

[0056] In the figure, 1. the first substation total meter, 101. the second substation total meter, 2. the fusion terminal, 3. the first multi-function meter, 301. the second multi-function meter, 4. the first phase-changing switch relay, 401. the second phase-changing switch relay, 5. the first reactive power compensation device, 501. the second reactive power compensation device, 6. the low-voltage intelligent leakage protection switch, 7. the first low-voltage intelligent switch, 8. the second low-voltage intelligent switch, 9. the first intelligent phase-changing switch, 10. the first intelligent micro-break switch, 11. the first single-phase meter, 12. the first single-phase simulated RLC load, 13. the second intelligent phase-changing switch, 14. the second intelligent micro-break switch, 15. the second single-phase meter, 16. the first three-phase Simulated RLC load, 17. The third low-voltage intelligent switch, 18. The fourth low-voltage intelligent switch, 19. The third intelligent micro-break switch, 20. The first three-phase meter, 21. The first RCD load, 22. The first photovoltaic inverter, 23. The first fault simulation device, 24. The second abnormal operation simulation device, 25. The first low-voltage molded case switch, 26. The first LTU, 27. The second low-voltage molded case switch, 28. The second LTU, 29. The third intelligent phase-changing switch, 30. The fourth intelligent micro-break switch, 31. The third single-phase meter, 32. The second three-phase simulated RLC load, 33. The third low-voltage molded case switch, 34. The third LTU, 35. The fourth low-voltage molded case switch Shell switch, 36. Fourth LTU, 37. Fifth intelligent micro-break switch, 38. Second three-phase meter, 39. Second RCD load, 40. Load equipment, 41. Fourth intelligent phase-changing switch, 42. Sixth intelligent micro-break switch, 43. Fourth single-phase meter, 44. Second single-phase simulated RLC load, 45. Second fault simulation device, 46. Second abnormal operation simulation device, 47. First distribution isolation transformer, 48. First intelligent environmental sensor, 49. Seventh intelligent micro-break switch, 50. Eighth intelligent micro-break switch, 51. Ninth intelligent micro-break switch, 52. Tenth intelligent micro-break switch, 53. Eleventh intelligent micro-break switch, 54. Twelfth Intelligent micro-break switch, 55. the thirteenth intelligent micro-break switch, 56. the fourteenth intelligent micro-break switch, 57. the fifteenth intelligent micro-break switch, 58. the sixteenth intelligent micro-break switch, 59. the seventeenth intelligent micro-break switch, 60. the eighteenth intelligent micro-break switch, 61. the nineteenth intelligent micro-break switch, 62. the twentieth intelligent micro-break switch, 63. the twenty-first intelligent micro-break switch, 64. the twenty-second intelligent micro-break switch, 65. the twenty-third intelligent micro-break switch, 66. the twenty-fourth intelligent micro-break switch, 67. the twenty-fifth intelligent micro-break switch, 68. the twenty-sixth intelligent micro-break switch, 69. the first distribution isolation transformer, 70. the first intelligent environmental sensor. DETAILED DESCRIPTION

[0057] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0058] Typical fault simulation test platform for low voltage distribution network, such as Figure 1 As shown, it includes a low-voltage substation simulation structure, which is connected to a substation fusion terminal through a wireless connection. The low-voltage substation simulation structure is also connected to a low-voltage fault simulation device and a low-voltage intelligent device through wiring terminals in the line. The low-voltage fault simulation device and the low-voltage intelligent device are also connected to the low-voltage substation simulation structure through a wireless connection. The low-voltage intelligent device is also connected to the low-voltage fault simulation device and the substation fusion terminal through a wireless connection.

[0059] The present invention sends fault preset instructions to the low-voltage fault simulation device and the low-voltage intelligent equipment through the low-voltage substation simulation structure, and can also directly simulate real faults through the low-voltage fault simulation device. After the low-voltage intelligent device senses the fault, it sends it to the substation fusion terminal. At the same time, the substation fusion terminal itself can also sense the fault information, and the back-end area fusion terminal sends the real-time alarm information to the low-voltage fault simulation test platform. The staff can view the specific alarm information through the platform large screen and carry out fault troubleshooting.

[0060] like Figure 2 As shown, the low-voltage area simulation structure includes partial discharge simulation, photovoltaic simulation, area topology monitoring, operation log, command window, integrated terminal node monitoring information display, load simulation control, micro-application test, fault simulation, communication protocol, equipment configuration, operation log record, and authority management. The low-voltage area simulation structure sends control instructions to the corresponding internal simulation module through HPLC to control the electrical value of the electrical circuit in the area; the fault simulation device is connected to the low-voltage area simulation structure through terminals, and the low-voltage area simulation structure can send instructions for generating preset faults to the fault simulation module through micro-power wireless (if operated on a large screen, the low-voltage area simulation structure can send instructions to the fault module through wireless methods for remote operation); the line side, low-voltage side, and user side of the low-voltage area simulation structure The simulation data of the intelligent devices on the line side, low-voltage side, and user side interact with the area fusion terminal data through HPLC and other methods to collect the electrical quantity and state quantity of the area; the main wiring diagram of the area and real-time alarm can be viewed on the display interface of the fault simulation platform. Each branch user sets the screen display to ensure that the access equipment at the end of all branches can be replaced, and the replacement equipment information is displayed on the screen of the corresponding branch.

[0061] Among them, the low-voltage area simulation structure includes the first area and the second area, such as Figure 3 , 4As shown, the low-voltage substation simulation structure includes a first substation and a second substation, the first substation includes a first distribution transformer side, the first distribution transformer side is connected to the first low-voltage side through a low-voltage bus, the first low-voltage side is connected to the first line side through the low-voltage bus, and the first line side is connected to the first user side through the low-voltage bus; the second substation includes a second distribution transformer side, the second distribution transformer side is connected to the second low-voltage side through the low-voltage bus, the second low-voltage side is connected to the second line side through the low-voltage bus, and the second line side is connected to the second user side through the low-voltage bus;

[0062] The substation fusion terminal is connected to the first distribution transformer side and the second distribution transformer side respectively through RS485 or micro-power wireless communication, the substation fusion terminal is connected to the first low-voltage side and the second low-voltage side respectively through RS485, remote signaling or micro-power wireless communication, the substation fusion terminal is connected to the first line side and the second line side respectively through micro-power wireless or HPLC communication, and the substation fusion terminal is connected to the first user side and the second user side respectively through HPLC communication or by adding a communication conversion unit.

[0063] like Figure 3 As shown, the first distribution transformer side includes a first distribution isolation transformer 47, the low-voltage side of the first distribution isolation transformer 47 is connected to the low-voltage bus at the power output end through a low-voltage intelligent leakage protection switch, and also includes a first intelligent environmental sensor 48. A low-voltage outgoing line on the low-voltage bus is connected to the first intelligent environmental sensor 48 through a low-voltage intelligent switch and then connected to the line side;

[0064] The first low-voltage side includes a first area total meter 1, a first multi-function meter 3, a first phase-changing switch relay 4 and a first reactive power compensation device 5, which are arranged in parallel and are respectively connected through the low-voltage outlet line of the low-voltage busbar;

[0065] The first line side includes a branch box No. 1 and a branch box No. 2, and the branch box No. 1 includes a first low-voltage intelligent switch 7, and the first low-voltage intelligent switch 7 is electrically connected to two second low-voltage intelligent switches 8, and the low-voltage outlet line of one of the second low-voltage intelligent switches 8 is electrically connected to three parallel first intelligent phase-changing switches 9, and the three first intelligent phase-changing switches 9 are electrically connected to a first single-phase meter 11, and each first single-phase meter 11 is provided with a first intelligent micro-break switch 10 on the wire connected to the first intelligent phase-changing switch 9, and the three first single-phase meters 11 are commonly connected to a first single-phase simulated RLC load 12, and another Two second intelligent phase-changing switches 13 are electrically connected to the low-voltage output line of the second low-voltage intelligent switch 8, and the two second intelligent phase-changing switches 13 are electrically connected to three second intelligent micro-break switches 14, respectively. Each second intelligent micro-break switch 14 is electrically connected to a second single-phase meter 15, and the output ends of the six second single-phase meters 15 are respectively connected to terminals, and also include a first three-phase simulated RLC load 16. The first three-phase simulated RLC load 16 can be connected to the three second single-phase meters 15 connected to the output end of any second intelligent phase-changing switch 13 through terminals. Here, it can be connected to the corresponding second single-phase meter 15 according to actual conditions.

[0066] The No. 2 branch box includes a third low-voltage intelligent switch 17, and the third low-voltage intelligent switch 17 is electrically connected to two fourth low-voltage intelligent switches 18, one of the fourth low-voltage intelligent switches 18 is connected to a terminal at the output end, which is a reserved interface for the load grounding side, and can simulate faults such as poor grounding, and the other fourth low-voltage intelligent switch 18 is electrically connected to three third intelligent micro-break switches 19, each of which is electrically connected to a first three-phase meter 20, each of which is electrically connected to a first RCD load 21, a first photovoltaic inverter 22 and a terminal, and the first photovoltaic inverter 22 is electrically connected to a photovoltaic simulation power supply;

[0067] The first station area also includes a first fault simulation device 23 and a second abnormal operation simulation device 24. The first fault simulation device 23 and the second abnormal operation simulation device 24 can be connected to corresponding terminals as needed;

[0068] All access devices are equipped with busbar connection and are compatible with external device access. All access devices are replaceable. Remote control switches are integrated before and after the busbar and connected to fault simulation devices to simulate line short circuit, open circuit and other faults.

[0069] like Figure 4 As shown, the second distribution transformer side includes a second distribution isolation transformer 69, the low-voltage side of the second distribution isolation transformer 69 is connected to the low-voltage bus at the power output end through a low-voltage intelligent leakage protection switch, and also includes a second intelligent environmental sensor 70. A low-voltage outgoing line on the low-voltage bus is connected to the second intelligent environmental sensor 70 through a low-voltage intelligent switch and then connected to the line side;

[0070] The second low-voltage side includes a second area master meter 101, a second multi-function meter 301, a second phase-changing switch relay 401, and a second reactive power compensation device 501. The second area master meter 101, the second multi-function meter 301, the second phase-changing switch relay 401, and the second reactive power compensation device 501 are arranged in parallel and are respectively connected to the low-voltage outgoing line of the low-voltage busbar;

[0071] The second line side includes branch box No. 3 and branch box No. 4, branch box No. 3 includes a first low-voltage molded case switch 25, the first low-voltage molded case switch 25 is electrically connected to a first LTU26, the first LTU26 is electrically connected to two second low-voltage molded case switches 27, the two second low-voltage molded case switches 27 are electrically connected to a second LTU28, one of the second LTU28 output ends is connected to a terminal, which is a reserved interface for the load grounding side, and can simulate faults such as poor grounding, and the other second LTU28 is electrically connected to two third intelligent phase-changing switches 29, each of the third intelligent phase-changing switches 29 is electrically connected to three fourth intelligent micro-break switches 30, each of the fourth intelligent micro-break switches 30 is electrically connected to a third single-phase meter 31, and the output ends of the six third single-phase meters 31 are respectively connected to terminals, and also includes a second three-phase simulated RLC load 32, the second three-phase simulated RLC load 32 can be connected to the three third single-phase meters 31 connected to the output end of any third intelligent phase-changing switch 29 through a terminal;

[0072] Branch box No. 4 includes a third low-voltage molded case switch 33, the third low-voltage molded case switch 33 is electrically connected to a third LTU34, the third LTU34 is electrically connected to two fourth low-voltage molded case switches 35, the two fourth low-voltage molded case switches 35 are electrically connected to a fourth LTU36, one of the fourth LTU36 is electrically connected to three fifth intelligent micro-break switches 37, each fifth intelligent micro-break switch 37 is electrically connected to a second three-phase meter 38, the three second three-phase meters 38 are respectively connected to a second RCD load 39, a load device 40 and a terminal, another fourth LTU36 is electrically connected to three fourth intelligent phase-changing switches 41, each fourth intelligent phase-changing switch 41 is electrically connected to a sixth intelligent micro-break switch 42, each sixth intelligent micro-break switch 42 is electrically connected to a fourth single-phase meter 43, and the three fourth single-phase meters 43 are electrically connected to a second single-phase simulated RLC load 44.

[0073] The second section also includes a second fault simulation device 45 and a second abnormal operation simulation device 46, which can be connected to corresponding terminals as needed;

[0074] The second substation is equipped with LTU equipment on the low-voltage molded case switch. All access devices are equipped with busbar connections and are compatible with external device access.

[0075] The first substation can switch between the TT system and the TNS system. A low-voltage outgoing line on the low-voltage side of the substation's power distribution isolation transformer is connected to the PE line. When the PE line is closed, the system is a three-phase five-wire TN-S system. At this time, the user equipment shell is grounded to the PE line; when the PE line is open, the system is a three-phase four-wire TT system, and the user equipment shell is grounded using independent direct grounding.

[0076] The second area can switch between the TNC and TNC-S systems through a remote switch. There is no PE line at the front end of the area. A low-voltage outgoing line on the low-voltage side of the distribution isolation transformer in the area is connected to the PE line. The system can be adjusted to two types:

[0077] Three-phase four-wire TN-C system: The user equipment shell is grounded using a common PEN line;

[0078] Three-phase four-wire TN-CS system: The user equipment casing is grounded partially by a common PEN wire and partially by a PE wire.

[0079] The method of conducting the test on the typical fault simulation test platform of the real distribution network in the low-voltage area is as follows:

[0080] S1. Connect the low-voltage fault simulation equipment in the general environment of low-voltage real-type test, and connect the equipment to be tested through the distribution network equipment access device;

[0081] S2. Adjust the adjustable load according to the test requirements;

[0082] The adjustable load can change the load type according to the fault form requirements. The adjustable load includes resistive load, capacitive load and inductive load, all of which are independently adjustable;

[0083] By controlling the thyristor control time and increasing the resistance to increase the current, the unbalanced three-phase current and instantaneous high current in the substation can be simulated.

[0084] Through the residual current test device, any phase residual current can occur, including normal residual current and fault residual current;

[0085] Remote control switches are integrated on the connection busbars of all access devices on the distribution transformer side, low voltage side, line side, and user side to achieve line switching and fault point access;

[0086] The harmonic generating device can be used to simulate the fault of voltage and current distortion, and the recording device can be used to record the waveform.

[0087] S3. Conduct fault simulation experiment operation: The low-voltage substation simulation structure sends fault preset instructions to the low-voltage fault simulation device and low-voltage intelligent equipment. The real fault can also be directly simulated through the low-voltage fault simulation device. After the low-voltage intelligent device senses the fault, it sends it to the substation fusion terminal. At the same time, the substation fusion terminal itself can also sense the fault information, and the back-end area fusion terminal sends the real-time alarm information to the low-voltage fault simulation test platform. The specific alarm information can be viewed on the platform large screen to carry out fault troubleshooting.

[0088] The low voltage fault simulation situations include the following:

[0089] The low-voltage fault simulation device is used to simulate various complex working conditions of the low-voltage distribution network, as well as single-phase grounding faults and high-current faults of the low-voltage distribution network;

[0090] Various complex working conditions of low-voltage distribution networks include three-phase imbalance, overvoltage, harmonic generation, topology changes, distributed power access, power theft, and line loss;

[0091] Single-phase grounding faults in low-voltage distribution networks include high-resistance grounding faults, low-resistance grounding faults, metallic grounding faults, arc grounding faults or intermittent grounding faults;

[0092] High current faults include phase-to-phase short circuit and three-phase short circuit.

[0093] S4. Test the state change of the device under test when a fault occurs to verify the quality of the device under test.

[0094] Through the above test method, single-phase grounding fault test, phase-to-phase short circuit, three-phase short circuit fault test, phase loss fault, broken neutral line fault, leakage fault, etc. of low-voltage distribution network can be carried out, which can reflect various fault locations, three-phase imbalance of low-voltage distribution network, overvoltage, harmonic generation, topology change, distributed power supply access, power theft, line loss and other complex working conditions.

[0095] The present invention realizes a comprehensive simulation of the operation of a typical low-voltage distribution network by building a typical low-voltage real distribution network test system, and introduces fault simulation and complex working condition scene reproduction equipment into the system, so as to provide effective means for equipment functional performance, algorithm research, and communication protocol verification. It is understandable that the construction of the low-voltage distribution network test system here cannot be completely simulated, and can be realized by combining digital simulation with real-type test. Specifically, for some scenes that cannot be realized by physical simulation, or the situation of a single simulation scene, digital simulation and real-type test are coordinated and cooperated, and data is interacted with the cloud master station, the intelligent fusion terminal of the distribution area, and the intelligent Internet of Things terminal, and semi-physical simulation is carried out. The existing hardware system is expanded through digital simulation, and more complex scene simulation is realized to solve the problem of equipment limitations. The simulation structure of the typical low-voltage distribution network simulation includes four levels: distribution transformer side, low-voltage side, line side, and user side. The real fault can be simulated by the low-voltage fault simulation device, and the perception data and information of each level are uniformly gathered in the distribution area fusion terminal for local data calculation and analysis application. The present invention can completely simulate the operating state and fault state of the actual low-voltage distribution network equipment, and truly simulate the test verification test circuit of the distribution network operating state;

[0096] The present invention is a typical fault simulation test platform for a real low-voltage distribution network in an actual area. It constructs a real low-voltage distribution network structure and truly reproduces the actual operating status of the low-voltage distribution network in the area. Complex fault simulation is performed on the basis of the distribution network. It can truly simulate the operating status of the low-voltage distribution network in the area and reproduce a variety of typical faults of the low-voltage distribution network, which solves the problem of equipment limitations and improves the refined operation and maintenance level of the low-voltage distribution network in the area.

[0097] The present invention constructs a typical low-voltage real distribution network test system, which can reproduce various complex faults of low-voltage distribution networks, realize flexible conversion of various fault types, various operating conditions, and various grounding forms, and provides a good test and verification platform for the full working condition assessment of low-voltage distribution network terminals. By combining the reproduction of complex working condition scenarios with the low-voltage power distribution real test environment, the convenient and rapid reproduction and replay of low-voltage distribution area operating conditions and typical fault scenarios can be achieved; the test system sets typical elements of distribution network source, network and load, and can truly reproduce the operating environment of the low-voltage distribution network, especially the problems of variable load level / current direction and the presence of harmonics; it can provide technical support and guidance for the implementation of new power system construction at the low-voltage distribution area level, and solve practical problems such as insufficient test environment and complicated test steps; it is conducive to better carrying out application research and exploratory verification of relevant key technologies such as intelligent Internet of Things in distribution areas; it is conducive to promoting the lean management capabilities of low-voltage distribution networks, customer service and distribution network operation management levels.

[0098] Example 1

[0099] Typical fault simulation test platform for low voltage distribution network, such as Figure 1 As shown, it includes a low-voltage substation simulation structure, which is connected to a substation fusion terminal through a wireless connection. The low-voltage substation simulation structure is also connected to a low-voltage fault simulation device and a low-voltage intelligent device through wiring terminals in the line. The low-voltage fault simulation device and the low-voltage intelligent device are also connected to the low-voltage substation simulation structure through a wireless connection. The low-voltage intelligent device is also connected to the low-voltage fault simulation device and the substation fusion terminal through a wireless connection.

[0100] The present invention sends fault preset instructions to the low-voltage fault simulation device and the low-voltage intelligent equipment through the low-voltage substation simulation structure, and can also directly simulate real faults through the low-voltage fault simulation device. After the low-voltage intelligent device senses the fault, it sends it to the substation fusion terminal. At the same time, the substation fusion terminal itself can also sense the fault information, and the back-end area fusion terminal sends the real-time alarm information to the low-voltage fault simulation test platform. The staff can view the specific alarm information through the platform large screen and carry out fault troubleshooting.

[0101] Among them, the low-voltage area simulation structure includes the first area and the second area, such as Figure 3 , 4 As shown, the low-voltage substation simulation structure includes a first substation and a second substation, the first substation includes a first distribution transformer side, the first distribution transformer side is connected to the first low-voltage side through a low-voltage bus, the first low-voltage side is connected to the first line side through the low-voltage bus, and the first line side is connected to the first user side through the low-voltage bus; the second substation includes a second distribution transformer side, the second distribution transformer side is connected to the second low-voltage side through the low-voltage bus, the second low-voltage side is connected to the second line side through the low-voltage bus, and the second line side is connected to the second user side through the low-voltage bus;

[0102] The substation fusion terminal is connected to the first distribution transformer side and the second distribution transformer side respectively through RS485 or micro-power wireless communication, the substation fusion terminal is connected to the first low-voltage side and the second low-voltage side respectively through RS485, remote signaling or micro-power wireless communication, the substation fusion terminal is connected to the first line side and the second line side respectively through micro-power wireless or HPLC communication, and the substation fusion terminal is connected to the first user side and the second user side respectively through HPLC communication or by adding a communication conversion unit.

[0103] The distribution transformer side of the first substation and the second substation includes a substation distribution isolation transformer 47. The low-voltage side of the substation distribution isolation transformer 47 is connected to the low-voltage bus at the power output end through a low-voltage intelligent leakage protection switch. It also includes an intelligent environmental sensor 48. One low-voltage outgoing line on the low-voltage bus is connected to the intelligent environmental sensor 48 through a low-voltage intelligent switch and then connected to the line side.

[0104] like Figure 3As shown, the first distribution transformer side includes a first distribution isolation transformer 47, the low-voltage side of the first distribution isolation transformer 47 is connected to the low-voltage bus at the power output end through a low-voltage intelligent leakage protection switch, and also includes a first intelligent environmental sensor 48. A low-voltage outgoing line on the low-voltage bus is connected to the first intelligent environmental sensor 48 through a low-voltage intelligent switch and then connected to the line side;

[0105] The first low-voltage side includes a first area total meter 1, a first multi-function meter 3, a first phase-changing switch relay 4 and a first reactive power compensation device 5, which are arranged in parallel and are respectively connected through the low-voltage outlet line of the low-voltage busbar;

[0106] The first line side includes a branch box No. 1 and a branch box No. 2, and the branch box No. 1 includes a first low-voltage intelligent switch 7, and the first low-voltage intelligent switch 7 is electrically connected to two second low-voltage intelligent switches 8, and the low-voltage outlet line of one of the second low-voltage intelligent switches 8 is electrically connected to three parallel first intelligent phase-changing switches 9, and the three first intelligent phase-changing switches 9 are electrically connected to a first single-phase meter 11, and each first single-phase meter 11 is provided with a first intelligent micro-break switch 10 on the wire connected to the first intelligent phase-changing switch 9, and the three first single-phase meters 11 are commonly connected to a first single-phase simulated RLC load 12, and another Two second intelligent phase-changing switches 13 are electrically connected to the low-voltage output line of the second low-voltage intelligent switch 8, and the two second intelligent phase-changing switches 13 are electrically connected to three second intelligent micro-break switches 14, respectively. Each second intelligent micro-break switch 14 is electrically connected to a second single-phase meter 15, and the output ends of the six second single-phase meters 15 are respectively connected to terminals, and also include a first three-phase simulated RLC load 16. The first three-phase simulated RLC load 16 can be connected to the three second single-phase meters 15 connected to the output end of any second intelligent phase-changing switch 13 through terminals. Here, it can be connected to the corresponding second single-phase meter 15 according to actual conditions.

[0107] The No. 2 branch box includes a third low-voltage intelligent switch 17, and the third low-voltage intelligent switch 17 is electrically connected to two fourth low-voltage intelligent switches 18, one of the fourth low-voltage intelligent switches 18 is connected to a terminal at the output end, which is a reserved interface for the load grounding side, and can simulate faults such as poor grounding, and the other fourth low-voltage intelligent switch 18 is electrically connected to three third intelligent micro-break switches 19, each of which is electrically connected to a first three-phase meter 20, each of which is electrically connected to a first RCD load 21, a first photovoltaic inverter 22 and a terminal, and the first photovoltaic inverter 22 is electrically connected to a photovoltaic simulation power supply;

[0108] The first station area also includes a first fault simulation device 23 and a second abnormal operation simulation device 24. The first fault simulation device 23 and the second abnormal operation simulation device 24 can be connected to corresponding terminals as needed;

[0109] All access devices are equipped with busbar connection and are compatible with external device access. All access devices are replaceable. Remote control switches are integrated before and after the busbar and connected to fault simulation devices to simulate line short circuit, open circuit and other faults.

[0110] like Figure 4 As shown, the second distribution transformer side includes a second distribution isolation transformer 69, the low-voltage side of the second distribution isolation transformer 69 is connected to the low-voltage bus at the power output end through a low-voltage intelligent leakage protection switch, and also includes a second intelligent environmental sensor 70. A low-voltage outgoing line on the low-voltage bus is connected to the second intelligent environmental sensor 70 through a low-voltage intelligent switch and then connected to the line side;

[0111] The second low-voltage side includes a second area master meter 101, a second multi-function meter 301, a second phase-changing switch relay 401, and a second reactive power compensation device 501. The second area master meter 101, the second multi-function meter 301, the second phase-changing switch relay 401, and the second reactive power compensation device 501 are arranged in parallel and are respectively connected to the low-voltage outgoing line of the low-voltage busbar;

[0112] The second line side includes branch box No. 3 and branch box No. 4, branch box No. 3 includes a first low-voltage molded case switch 25, the first low-voltage molded case switch 25 is electrically connected to a first LTU26, the first LTU26 is electrically connected to two second low-voltage molded case switches 27, the two second low-voltage molded case switches 27 are electrically connected to a second LTU28, one of the second LTU28 output ends is connected to a terminal, which is a reserved interface for the load grounding side, and can simulate faults such as poor grounding, and the other second LTU28 is electrically connected to two third intelligent phase-changing switches 29, each of the third intelligent phase-changing switches 29 is electrically connected to three fourth intelligent micro-break switches 30, each of the fourth intelligent micro-break switches 30 is electrically connected to a third single-phase meter 31, and the output ends of the six third single-phase meters 31 are respectively connected to terminals, and also includes a second three-phase simulated RLC load 32, the second three-phase simulated RLC load 32 can be connected to the three third single-phase meters 31 connected to the output end of any third intelligent phase-changing switch 29 through a terminal;

[0113] Branch box No. 4 includes a third low-voltage molded case switch 33, the third low-voltage molded case switch 33 is electrically connected to a third LTU34, the third LTU34 is electrically connected to two fourth low-voltage molded case switches 35, the two fourth low-voltage molded case switches 35 are electrically connected to a fourth LTU36, one of the fourth LTU36 is electrically connected to three fifth intelligent micro-break switches 37, each fifth intelligent micro-break switch 37 is electrically connected to a second three-phase meter 38, the three second three-phase meters 38 are respectively connected to a second RCD load 39, a load device 40 and a terminal, another fourth LTU36 is electrically connected to three fourth intelligent phase-changing switches 41, each fourth intelligent phase-changing switch 41 is electrically connected to a sixth intelligent micro-break switch 42, each sixth intelligent micro-break switch 42 is electrically connected to a fourth single-phase meter 43, and the three fourth single-phase meters 43 are electrically connected to a second single-phase simulated RLC load 44.

[0114] The second section also includes a second fault simulation device 45 and a second abnormal operation simulation device 46, which can be connected to corresponding terminals as needed;

[0115] The second substation is equipped with LTU equipment on the low-voltage molded case switch. All access devices are equipped with busbar connections and are compatible with external device access.

[0116] The first substation can switch between the TT system and the TNS system. A low-voltage outgoing line on the low-voltage side of the substation's power distribution isolation transformer is connected to the PE line. When the PE line is closed, the system is a three-phase five-wire TN-S system. At this time, the user equipment shell is grounded to the PE line; when the PE line is open, the system is a three-phase four-wire TT system, and the user equipment shell is grounded using independent direct grounding.

[0117] The second area can switch between the TNC and TNC-S systems through a remote switch. There is no PE line at the front end of the area. A low-voltage outgoing line on the low-voltage side of the distribution isolation transformer in the area is connected to the PE line. The system can be adjusted to two types:

[0118] Three-phase four-wire TN-C system: The user equipment shell is grounded using a common PEN line;

[0119] Three-phase four-wire TN-CS system: The user equipment casing is grounded partially by a common PEN wire and partially by a PE wire.

[0120] Example 2

[0121] The method of conducting the test on the typical fault simulation test platform of the real distribution network in the low-voltage area is as follows:

[0122] S1. Connect the low-voltage fault simulation equipment in the general environment of low-voltage real-type test, and connect the equipment to be tested through the distribution network equipment access device;

[0123] S2. Adjust the adjustable load according to the test requirements;

[0124] The adjustable load can change the load type according to the fault form requirements. The adjustable load includes resistive load, capacitive load and inductive load, all of which are independently adjustable;

[0125] By controlling the thyristor control time and increasing the resistance to increase the current, the unbalanced three-phase current and instantaneous high current in the substation can be simulated.

[0126] Through the residual current test device, any phase residual current can occur, including normal residual current and fault residual current;

[0127] Remote control switches are integrated on the connection busbars of all access devices on the distribution transformer side, low voltage side, line side, and user side to achieve line switching and fault point access;

[0128] The harmonic generating device can be used to simulate the fault of voltage and current distortion, and the recording device can be used to record the waveform.

[0129] S3. Conduct fault simulation experiment operation: The low-voltage substation simulation structure sends fault preset instructions to the low-voltage fault simulation device and low-voltage intelligent equipment. The real fault can also be directly simulated through the low-voltage fault simulation device. After the low-voltage intelligent device senses the fault, it sends it to the substation fusion terminal. At the same time, the substation fusion terminal itself can also sense the fault information, and the back-end area fusion terminal sends the real-time alarm information to the low-voltage fault simulation test platform. The specific alarm information can be viewed on the platform large screen to carry out fault troubleshooting.

[0130] The low voltage fault simulation situations include the following:

[0131] The low-voltage fault simulation device is used to simulate various complex working conditions of the low-voltage distribution network, as well as single-phase grounding faults and high-current faults of the low-voltage distribution network;

[0132] Various complex working conditions of low-voltage distribution networks include three-phase imbalance, overvoltage, harmonic generation, topology changes, distributed power access, power theft, and line loss;

[0133] Single-phase grounding faults in low-voltage distribution networks include high-resistance grounding faults, low-resistance grounding faults, metallic grounding faults, arc grounding faults or intermittent grounding faults;

[0134] High current faults include phase-to-phase short circuit and three-phase short circuit.

[0135] S4. Test the state change of the device under test when a fault occurs to verify the quality of the device under test.

[0136] Example 3

[0137] like Figure 5 As shown, the low-voltage fault simulation device realizes line fault simulation, including short circuit, single-phase grounding and other faults, and has functions such as line overload protection, controllable short circuit time, and flexible access interface.

[0138] Figure 5 Among them, the seventh intelligent micro-break switch 49 selects an intelligent short-circuit device (rated current 200-250A) and is equipped with a low-voltage protection device; the eighth intelligent micro-break switch 50 and the ninth intelligent micro-break switch 51 select a three-phase contactor (rated current 200A); the tenth intelligent micro-break switch 52, the eleventh intelligent micro-break switch 53, the twelfth intelligent micro-break switch 54, the thirteenth intelligent micro-break switch 55, the fourteenth intelligent micro-break switch 56, and the fifteenth intelligent micro-break switch 57 select a three-phase contactor (rated current 100A); the sixteenth intelligent micro-break switch 58 is used to generate a 500A current and selects a three-phase contactor. The seventeenth intelligent micro-break switch 59 is used to generate a 400A current and select a three-phase contactor (rated current 180A); the eighteenth intelligent micro-break switch 60 is used to generate a 300A current and select a three-phase contactor (rated current 160A); the nineteenth intelligent micro-break switch 61 is used to generate a 200A current and select a three-phase contactor (rated current 120A); the twentieth intelligent micro-break switch 62 is used to generate a 100A current and select a three-phase contactor (rated current 60A); the thyristor is selected to be 1000A, 1200V (PK1000A withstand voltage 1200V).

[0139] A low-voltage protection device is used to trip the seventh intelligent micro-breaker 49 of the incoming line when the system is overcurrent to ensure safe and reliable operation of the device. The low-voltage protection device should have a three-stage protection function.

[0140] The control method is: all contactors are controlled through the control panel of the low-voltage fault simulation device. The fault generation time can be set from 1 to 5S, and the simulated fault current is 500A, 400A, 300A, 200A, and 100A.

[0141] When a single-phase grounding fault occurs, the control panel of the low-voltage fault simulation device controls the ninth intelligent micro-break switch 51, the thirteenth intelligent micro-break switch 55, the fourteenth intelligent micro-break switch 56, and the fifteenth intelligent micro-break switch 57. The thirteenth intelligent micro-break switch 55, the fourteenth intelligent micro-break switch 56, and the fifteenth intelligent micro-break switch 57 can respectively simulate the single-phase grounding faults of phases A, B, and C. The transition resistor is selected by controlling the twenty-first intelligent micro-break switch 63, the twenty-second intelligent micro-break switch 64, the twenty-third intelligent micro-break switch 65, the twenty-fourth intelligent micro-break switch 66, and the twenty-fifth intelligent micro-break switch 67 through the control panel;

[0142] When a phase-to-phase short circuit fault occurs, the control panel of the low-voltage fault simulation device controls the eighth intelligent micro-break switch 50, the twenty-sixth intelligent micro-break switch 68, the tenth intelligent micro-break switch 52, the eleventh intelligent micro-break switch 53, the twelfth intelligent micro-break switch 54, the sixteenth intelligent micro-break switch 58, the seventeenth intelligent micro-break switch 59, the eighteenth intelligent micro-break switch 60, the nineteenth intelligent micro-break switch 61, and the twentieth intelligent micro-break switch 62. The tenth intelligent micro-break switch 52, the eleventh intelligent micro-break switch 53, and the twelfth intelligent micro-break switch 54 can respectively simulate the A, B, and C phase-to-phase faults, and the simulated fault current can be simulated by controlling the twenty-first intelligent micro-break switch 63, the twenty-second intelligent micro-break switch 64, the twenty-third intelligent micro-break switch 65, the twenty-fourth intelligent micro-break switch 66, and the twenty-fifth intelligent micro-break switch 67 through the control panel.

Claims

1. Low-voltage distribution network typical fault simulation test platform, characterized by: It includes a low-voltage substation simulation structure, which is connected to a substation fusion terminal via a wireless connection. The low-voltage substation simulation structure is also connected to a low-voltage fault simulation device and a low-voltage intelligent device via wiring terminals in the line. The low-voltage fault simulation device and the low-voltage intelligent device are also connected to the low-voltage substation simulation structure via a wireless connection. The low-voltage intelligent device is also connected to the low-voltage fault simulation device and the substation fusion terminal via a wireless connection.

2. According to claim 1, the low-voltage distribution network typical fault simulation test platform is characterized in that: The low-voltage substation simulation structure includes a first substation and a second substation, the first substation includes a first distribution transformer side, the first distribution transformer side is connected to the first low-voltage side through a low-voltage bus, the first low-voltage side is connected to the first line side through the low-voltage bus, and the first line side is connected to the first user side through the low-voltage bus; the second substation includes a second distribution transformer side, the second distribution transformer side is connected to the second low-voltage side through the low-voltage bus, the second low-voltage side is connected to the second line side through the low-voltage bus, and the second line side is connected to the second user side through the low-voltage bus; The substation fusion terminal is connected to the first distribution transformer side and the second distribution transformer side respectively through RS485 or micro-power wireless communication, the substation fusion terminal is connected to the first low-voltage side and the second low-voltage side respectively through RS485, remote signaling or micro-power wireless communication, the substation fusion terminal is connected to the first line side and the second line side respectively through micro-power wireless or HPLC communication, and the substation fusion terminal is connected to the first user side and the second user side respectively through HPLC communication or by adding a communication conversion unit.

3. According to claim 2, the low-voltage distribution network typical fault simulation test platform is characterized in that: The first distribution transformer side comprises a first distribution isolation transformer (47), a low-voltage side of the first distribution isolation transformer (47) is connected to a low-voltage bus at a power output end via a low-voltage intelligent leakage protection switch, and also comprises a first intelligent environmental sensor (48), a low-voltage outgoing line on the low-voltage bus is connected to the first intelligent environmental sensor (48) via a low-voltage intelligent switch and then connected to the line side; The first low-voltage side comprises a first area master meter (1), a first multifunctional meter (3), a first phase-changing switch relay (4) and a first reactive power compensation device (5); the first area master meter (1), the first multifunctional meter (3), the first phase-changing switch relay (4) and the first reactive power compensation device (5) are arranged in parallel and are respectively connected through low-voltage outlet lines of a low-voltage busbar; The first line side comprises a No. 1 branch box and a No. 2 branch box, wherein the No. 1 branch box comprises a first low-voltage intelligent switch (7), wherein the first low-voltage intelligent switch (7) is electrically connected to two second low-voltage intelligent switches (8), wherein the low-voltage outlet line of one of the second low-voltage intelligent switches (8) is electrically connected to three parallel first intelligent phase-changing switches (9), wherein the three first intelligent phase-changing switches (9) are electrically connected to a first single-phase meter (11), wherein each first single-phase meter (11) is provided with a first intelligent micro-break switch (10) on the wire connected to the first intelligent phase-changing switch (9), and the three first single-phase meters (11) are commonly connected to a first single-phase analog RLC load (12), two second intelligent phase-changing switches (13) are electrically connected to the low-voltage outlet line of another second low-voltage intelligent switch (8), the two second intelligent phase-changing switches (13) are electrically connected to three second intelligent micro-break switches (14), each of the second intelligent micro-break switches (14) is electrically connected to a second single-phase meter (15), the output ends of the six second single-phase meters (15) are respectively connected to terminals, and also include a first three-phase simulated RLC load (16), the first three-phase simulated RLC load (16) can be connected to the three second single-phase meters (15) connected to the output end of any second intelligent phase-changing switch (13) through the terminals; The No. 2 branch box comprises a third low-voltage intelligent switch (17), the third low-voltage intelligent switch (17) is electrically connected to two fourth low-voltage intelligent switches (18), one of the fourth low-voltage intelligent switches (18) is electrically connected to a terminal at its output end, and the other fourth low-voltage intelligent switch (18) is electrically connected to three third intelligent micro-break switches (19), each of the third intelligent micro-break switches (19) is electrically connected to a first three-phase meter (20), each of the first three-phase meters (20) is electrically connected to a first RCD load (21), a first photovoltaic inverter (22) and a terminal, and the first photovoltaic inverter (22) is electrically connected to a photovoltaic simulation power supply; The first station area also includes a first fault simulation device (23) and a second abnormal operation simulation device (24), and the first fault simulation device (23) and the second abnormal operation simulation device (24) can be connected to corresponding terminals as needed; All access devices are equipped with busbar connection and are compatible with external device access. All access devices are replaceable. Remote control switches are integrated before and after the busbar and connected to fault simulation devices to simulate line short circuit, open circuit and other faults.

4. According to claim 2, the low-voltage distribution network typical fault simulation test platform is characterized in that: The second distribution transformer side comprises a second distribution isolation transformer (69), the low-voltage side of the second distribution isolation transformer (69) is connected to the low-voltage bus at the power output end through a low-voltage intelligent leakage protection switch, and also comprises a second intelligent environmental sensor (70), and a low-voltage output line on the low-voltage bus is connected to the second intelligent environmental sensor (70) through a low-voltage intelligent switch and then connected to the line side; The second low-voltage side comprises a second area master meter (101), a second multi-function meter (301), a second phase-changing switch relay (401), and a second reactive power compensation device (501); the second area master meter (101), the second multi-function meter (301), the second phase-changing switch relay (401), and the second reactive power compensation device (501) are arranged in parallel and are respectively connected to the low-voltage outgoing line of the low-voltage bus; The second line side includes a No. 3 branch box and a No. 4 branch box, the No. 3 branch box includes a first low-voltage molded case switch (25), the first low-voltage molded case switch (25) is electrically connected to a first LTU (26), the first LTU (26) is electrically connected to two second low-voltage molded case switches (27), the two second low-voltage molded case switches (27) are electrically connected to a second LTU (28), one of the second LTUs (28) has an output end connected to a terminal, and the other second LTU (28) is electrically connected to two third An intelligent phase-changing switch (29), each of the third intelligent phase-changing switches (29) is electrically connected to three fourth intelligent micro-breaking switches (30), each of the fourth intelligent micro-breaking switches (30) is electrically connected to a third single-phase meter (31), the output ends of the six third single-phase meters (31) are respectively connected to terminals, and also includes a second three-phase simulated RLC load (32), the second three-phase simulated RLC load (32) can be connected to the three third single-phase meters (31) connected to the output end of any third intelligent phase-changing switch (29) through the terminal; The No. 4 branch box comprises a third low-voltage molded case switch (33), the third low-voltage molded case switch (33) is electrically connected to a third LTU (34), the third LTU (34) is electrically connected to two fourth low-voltage molded case switches (35), the two fourth low-voltage molded case switches (35) are electrically connected to a fourth LTU (36), one of the fourth LTUs (36) is electrically connected to three fifth intelligent micro-break switches (37), each of the fifth intelligent micro-break switches (37) is electrically connected to a second three-phase meter (38), ), three of the second three-phase meters (38) are respectively connected to a second RCD load (39), a load device (40) and a terminal, another fourth LTU (36) is respectively electrically connected to three fourth intelligent phase-changing switches (41), each of the fourth intelligent phase-changing switches (41) is respectively electrically connected to a sixth intelligent micro-break switch (42), each of the sixth intelligent micro-break switches (42) is respectively electrically connected to a fourth single-phase meter (43), and the three fourth single-phase meters (43) are commonly electrically connected to a second single-phase simulated RLC load (44); The second station area also includes a second fault simulation device (45) and a second abnormal operation simulation device (46), and the second fault simulation device (45) and the second abnormal operation simulation device (46) can be connected to corresponding terminals as needed; The second substation is equipped with LTU equipment on the low-voltage molded case switch, all access devices are equipped with busbar connection, and are compatible with external device access.

5. According to claim 2, the low-voltage distribution network typical fault simulation test platform is characterized in that: The first substation can switch between the TT system and the TNS system. A low-voltage outgoing line on the low-voltage side of the substation power distribution isolation transformer is connected to the PE line. When the PE line is closed, the system is a three-phase five-wire TN-S system. At this time, the user equipment shell is grounded to the PE line; when the PE line is open, the system is a three-phase four-wire TT system, and the user equipment shell is grounded using independent direct grounding. The second substation can switch between the TNC and TNC-S systems through a remote switch. There is no PE line at the front end of the substation. A low-voltage outgoing line on the low-voltage side of the substation power distribution isolation transformer is connected to the PE line. The system can be adjusted to two types: Three-phase four-wire TN-C system: The user equipment shell is grounded using a common PEN line; Three-phase four-wire TN-CS system: The user equipment casing is grounded partially by a common PEN wire and partially by a PE wire.

6. A method for performing a fault simulation test using the low-voltage distribution network typical fault simulation test platform described in any one of claims 1 to 5, characterized in that: The specific steps are as follows: S1. Connect the low-voltage fault simulation equipment in the general environment of low-voltage real-type test, and connect the equipment to be tested through the distribution network equipment access device; S2. Adjust the adjustable load according to the test requirements; S3. Conduct fault simulation experiment operation; S4. Test the state change of the device under test when a fault occurs to verify the quality of the device under test.

7. The method for conducting a test using a typical fault simulation test platform for a real distribution network in a low-voltage area according to claim 6 is characterized in that: The S2 is specifically: The adjustable load can change the load type according to the fault form requirements. The adjustable load includes resistive load, capacitive load and inductive load, all of which are independently adjustable; By controlling the thyristor control time and increasing the resistance to increase the current, the unbalanced three-phase current and instantaneous high current in the substation can be simulated. Through the residual current test device, any phase residual current can occur, including normal residual current and fault residual current; Remote control switches are integrated on the connection busbars of all access devices on the distribution transformer side, low voltage side, line side, and user side to achieve line switching and fault point access; The harmonic generating device can be used to simulate the fault of voltage and current distortion, and the recording device can be used to record the waveform.

8. The method for conducting a test using a typical fault simulation test platform for a real distribution network in a low-voltage area according to claim 6 is characterized in that: The specific method of S3 is: the low-voltage substation simulation structure sends fault preset instructions to the low-voltage fault simulation device and the low-voltage intelligent device, and the real fault can also be directly simulated by the low-voltage fault simulation device. After the low-voltage intelligent device senses the fault, it sends it to the substation fusion terminal. At the same time, the substation fusion terminal itself can also sense the fault information. Then the substation fusion terminal sends the real-time alarm information to the low-voltage fault simulation test platform. The specific alarm information can be viewed through the platform large screen to carry out fault troubleshooting.

9. The method for conducting a test using a typical fault simulation test platform for a real distribution network in a low-voltage area according to claim 6 is characterized in that: The S3 low voltage fault simulation includes the following: The low-voltage fault simulation device is used to simulate various complex working conditions of the low-voltage distribution network, as well as single-phase grounding faults and high-current faults of the low-voltage distribution network; The various complex operating conditions of the low-voltage distribution network include three-phase imbalance, overvoltage, harmonic generation, topology change, distributed power supply access, power theft, and line loss; The single-phase grounding fault of the low-voltage distribution network includes a high-resistance grounding fault, a low-resistance grounding fault, a metallic grounding fault, an arc grounding fault or an intermittent grounding fault; The high current fault includes phase-to-phase short circuit and three-phase short circuit.

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