A low-pressure fire test system and method for forest and pasture areas

Abstract

The present application relates to the technical field of electrical safety, and more particularly to a low-voltage fire test system and method for forestry and animal husbandry areas, comprising a low-voltage power distribution cabinet, a power supply system, a wave recording system and a fault simulation area; the fault simulation area is used for simulating the fault of overhead lines with different diameters or insulation characteristics in various types of overhead line fault simulation tests according to pre-set test conditions; the power supply system is used for outputting alternating current with three-phase voltage when simulating different types of overhead line faults; the low-voltage power distribution cabinet is used for detecting the three-phase voltage of the bus and the three-phase current of the outgoing line under different overhead line fault types, so that the wave recording system detects whether there is arc breakdown and obtains corresponding fault simulation information. The present application can effectively analyze the short-circuit arc condition in the fault process by testing various fault types of overhead transmission lines and plant combustion, thereby reducing the probability of fire caused by power distribution network faults in forestry and animal husbandry areas.

Description

Technical Field

[0001] The present invention relates to the field of electrical safety technology, and in particular to a low-voltage fire test system and method in forest and pastoral areas. Background Art

[0002] With the rapid development of the national economy, the demand for electricity in all walks of life is increasing. The introduction of concepts such as global energy Internet and smart grid has made the distribution network gradually become a research hotspot for relevant scholars at home and abroad. The distribution network is at the end of the power system and is most closely connected with electricity users such as residents and factories. It is an indispensable part of the power system. However, the distribution network has the characteristics of many outgoing lines, complex network structure, various neutral point grounding methods, and extremely high probability of feeder failure. Among them, single-phase grounding faults account for the largest proportion, with a failure probability of nearly 80%.

[0003] Traditional distribution network operating regulations stipulate that when the ground current is less than 10A, the network can continue to operate with a fault for two hours. However, most of the power electronic equipment currently used in the distribution network are non-linear loads, and the proportion of cable lines is increasing. Therefore, the reactive component, active component and harmonic content in the ground fault current are getting higher and higher. The active current and harmonic current components in the ground fault can account for more than 10% of the total current. In this case, the fault residual current is large, and the residual active or harmonic components are sufficient to cause the arc to fail to extinguish itself, and may even cause overvoltage and further development of the fault, thereby affecting the stable operation of the power grid, equipment damage, personal safety and the occurrence of fires in forest and pastoral areas. Therefore, there is an urgent need to provide a scientific, accurate and reliable low-voltage fire test system for forest and pastoral areas. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-voltage fire test system and method for forest and pastoral areas, so as to effectively analyze the short-circuit arc situation during the fault process by testing various fault types and plant combustion, and reduce the probability of fire caused by distribution network faults in forest and pastoral areas.

[0005] In order to solve the above technical problems, the present invention provides a low-pressure fire test system and method for forest and pastoral areas.

[0006] In a first aspect, the present invention provides a low-voltage fire test system for forest and pastoral areas, the system comprising a low-voltage power distribution cabinet and a power supply system, a wave recording system, and a fault simulation area connected to the low-voltage power distribution cabinet;

[0007] The fault simulation area is used to simulate overhead line faults of various types according to pre-set test conditions in various overhead line fault simulation tests;

[0008] The power supply system is used to output three-phase AC power to the low-voltage distribution cabinet through the distribution transformer when simulating different types of overhead line faults;

[0009] The low-voltage distribution cabinet is used to detect the busbar three-phase voltage and the outgoing line three-phase current under different overhead line fault types through a three-phase current transformer and a three-phase voltage transformer after receiving the three-phase alternating current;

[0010] The recording system is used to detect whether there is arc breakdown based on the received busbar three-phase voltage and the outgoing line three-phase current, and obtain corresponding fault simulation information.

[0011] In a further embodiment, the power system includes a single-phase power source, a pole-mounted circuit breaker, and a distribution transformer;

[0012] The single-phase power supply is connected to the distribution transformer through the pole-mounted circuit breaker, and the distribution transformer is connected to the three-phase input terminal of the low-voltage distribution cabinet through the three-phase conductor of the overhead line.

[0013] In a further embodiment, the low-voltage power distribution cabinet includes a three-phase fuse-type disconnector, a three-phase current transformer, and a three-phase overhead line air circuit breaker provided on the overhead line, the three-phase fuse-type disconnector is connected to the three-phase overhead line air circuit breaker via the three-phase current transformer, and the fault simulation area is connected to the output end of the three-phase overhead line air circuit breaker;

[0014] The low-voltage power distribution cabinet further includes a three-phase voltage transformer, which is connected between the three-phase current transformer and the three-phase overhead line air circuit breaker through a three-phase air circuit breaker.

[0015] In a further embodiment, the system further comprises a control system connected to an input of the low voltage distribution cabinet;

[0016] The control system is used to remotely control the operation of the three-phase fuse-type disconnector in the low-voltage distribution cabinet when starting the overhead line fault simulation test, so as to boost the voltage on the high-voltage side of the distribution transformer, and after the voltage on the high-voltage side of the distribution transformer is boosted to a preset voltage value, remotely control the operation of the three-phase overhead line air circuit breaker and the three-phase air circuit breaker.

[0017] In a further embodiment, the test conditions include single-phase grounding fault test conditions, single-phase line break fault test conditions, two-phase short circuit fault test conditions and forest and pastoral plant burning test conditions.

[0018] In a further embodiment, the single-phase ground fault test condition is specifically as follows:

[0019] An overhead transmission line is fixed using two insulating brackets with fixtures, and one side of the overhead transmission line is connected to a power supply system, while the other side of the overhead transmission line is suspended in the air. The insulation in the middle of the overhead transmission line is removed to expose the bottom of the overhead transmission line, so that combustibles can be placed on the pole plate under the exposed overhead transmission line, wherein the pole plate is grounded and a lifting device is placed under the pole plate to adjust the discharge distance between the overhead transmission line through the combustibles and the ground by the lifting device.

[0020] In a further embodiment, the single-phase line break fault test condition is specifically as follows:

[0021] Two insulating brackets with fixers are used to fix the overhead transmission line. One side of the overhead transmission line is connected to the power system, and the other side of the overhead transmission line is placed above the grounded electrode. A tripod is used in the middle of the overhead transmission line to adjust the distance between the cross section of the overhead transmission line and the electrode. An adjustable transition resistor is connected to the overhead line between the insulating bracket and the tripod to adjust the breakdown fault current value through the adjustable transition resistor, and combustibles are placed above the electrode.

[0022] In a further embodiment, the two-phase short circuit fault test condition is specifically as follows:

[0023] Connect the load at the end of the three-phase overhead transmission line, place the two-phase short-circuit touch objects directly above the A and B phases of the overhead transmission line in the power-off state, adjust the distance of the three-phase line and perform the power-on test.

[0024] In a further embodiment, the fault simulation area further includes a monitoring system;

[0025] The monitoring system is used to monitor the simulation test of the fault simulation area in real time.

[0026] In a second aspect, the present invention provides a low-pressure fire test method for forest and pastoral areas, the method comprising the following steps:

[0027] In various types of overhead line fault simulation tests, simulated tests are conducted on overhead line faults of different diameters or insulation characteristics according to pre-set test conditions;

[0028] When simulating different types of overhead line faults, the distribution transformer outputs three-phase AC voltage, and detects the busbar three-phase voltage and outgoing line three-phase current under different overhead line fault types;

[0029] Whether there is arc breakdown is detected based on the received busbar three-phase voltage and the outgoing line three-phase current, and corresponding fault simulation information is obtained.

[0030] The present invention provides a low-voltage fire test system and method for forest and pastoral areas. The system includes a low-voltage power distribution cabinet, a power supply system, a recording system, and a fault simulation area. The fault simulation area is used to simulate overhead line faults of different diameters or insulation characteristics according to pre-set test conditions in various types of overhead line fault simulation tests. The power supply system is used to output three-phase alternating current when simulating different types of overhead line faults. The low-voltage power distribution cabinet is used to detect the busbar three-phase voltage and outgoing line three-phase current under different overhead line fault types, so that the recording system can detect whether there is arc breakdown and obtain corresponding fault simulation information. The present invention tests various types of overhead transmission line faults and plant combustion, and simultaneously records waveforms through the fault recording system, thereby effectively analyzing the short-circuit arc situation during the fault process, providing data support for analyzing fires caused by distribution network faults in forest and pastoral areas, and reducing the probability of fires caused by distribution network faults in forest and pastoral areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a block diagram of a low-voltage fire test system for forest and pastoral areas provided by an embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of a power supply system provided by an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the test operation flow provided by an embodiment of the present invention;

[0034] Figure 4 Schematic diagram of a single-phase ground fault test operating condition provided by an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of a single-phase line break fault test operating condition provided by an embodiment of the present invention;

[0036] Figure 6 Schematic diagram of a two-phase short-circuit fault test operating condition provided by an embodiment of the present invention;

[0037] Figure 7 Schematic diagram of a test condition for generating splashing combustibles from a high-temperature melt according to an embodiment of the present invention;

[0038] Figure 8 Schematic diagram of a test condition of an overhead line affected by a wildfire provided by an embodiment of the present invention;

[0039] Figure 9 It is a flow chart of a low-pressure fire test method in forest and pastoral areas provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following describes the embodiments of the present invention in detail with reference to the accompanying drawings. The embodiments are provided for illustrative purposes only and are not to be construed as limiting the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute a limitation on the scope of protection of the present invention. Many changes may be made to the present invention without departing from the spirit and scope of the present invention.

[0041] refer to Figure 1 The embodiment of the present invention provides a low-pressure fire test system for forest and pastoral areas, such as Figure 1 As shown, the system includes: a low-voltage distribution cabinet 10 and a power supply system 11, a control system 12, a recording system 13 and a fault simulation area 14 connected to the low-voltage distribution cabinet 10. In this embodiment, the fault simulation area, low-voltage distribution cabinet, high-voltage circuit breaker, disconnector, mutual inductor and other equipment in the test system are all installed outdoors, while the power supply system, control system, transformer and recording system are all installed indoors to ensure the safety of the test personnel.

[0042] In one embodiment, a monitoring system and an overhead transmission line are provided in the fault simulation area 14. The fault simulation area is used to simulate overhead line faults of different diameters or insulation characteristics according to pre-set test conditions in various types of overhead line fault simulation tests. In this embodiment, the overhead transmission line set in the fault simulation area preferably uses steel core aluminum stranded wire (ACSR), which is made of aluminum wire and steel wire twisted together. The test platform can provide LGJ-10 bare conductor, LGJ-35 steel core aluminum stranded wire, LGJ-70 steel core aluminum stranded wire, and LGJ-120 steel core aluminum stranded wire to detect the ability of overhead lines of different diameters and whether they are insulated to cope with faults. Among them, L is the abbreviation of aluminum wire, G is the abbreviation of steel core, and J is the abbreviation of stranded wire; the steel core mainly serves to increase strength, and the aluminum stranded wire mainly serves to transmit electrical energy. Those skilled in the art can replace the overhead transmission line according to the specific implementation situation, which is not limited to the present invention.

[0043] In this embodiment, the fault simulation area 14 is used to realistically simulate various fault types of overhead lines with different diameters and insulation characteristics to detect the ability of overhead lines to cope with faults, for example, to simulate various types of faults such as single-phase grounding, line break faults and two-phase short circuit faults. At the same time, the simulation test of the fault simulation area is monitored in real time by the monitoring system. The fault simulation area in this embodiment can also conduct tree grounding tests on overhead lines and burning tests of plants such as pine needles and pine leaves in forest and pastoral areas in a targeted manner based on the conditions of densely populated trees in forest and pastoral areas, so as to simulate and analyze the operation of distribution network lines in forest and pastoral areas affected by wildfires.

[0044] In one embodiment, the power supply system 11 includes a single-phase power supply, a pole-mounted circuit breaker and a distribution transformer, wherein the single-phase power supply is connected to the distribution transformer through the pole-mounted circuit breaker, and the distribution transformer is connected to the three-phase input end of the low-voltage distribution cabinet through the three-phase conductor of the overhead line; the power supply system is used to simulate different types of overhead line faults in the fault simulation area, and output three-phase voltage AC to the low-voltage distribution cabinet through the distribution transformer.

[0045] Specifically, if Figure 2 As shown, the power supply system 11 used in this embodiment is a 10kV power supply system for providing power signal input. The 10kV power supply system includes a 10kV single-phase power supply, a 10kV voltage-level pole-mounted circuit breaker 1KM and a distribution transformer 1T, so as to supply power to the distribution transformer 1T through the 10kV voltage-level pole-mounted circuit breaker 1KM, thereby outputting three-phase 380V AC power through the output end of the distribution transformer 1T. In this embodiment, the model parameters of the distribution transformer 1T are preferably set to 200kVA 10500 / 400V. After the transformation of the distribution transformer 1T and the action of power electronic components, the output voltage is three-phase 380V AC power. The 380V side of the distribution transformer adopts the TN-C system, and a 200A fuse and a 100A air switch are connected in series in the low-voltage distribution cabinet for short-circuit differential coordination.

[0046] In one embodiment, the low-voltage distribution cabinet 10 includes a three-phase fuse-type disconnector, a three-phase current transformer and a three-phase overhead line air circuit breaker arranged on the overhead line, the three-phase fuse-type disconnector is connected to the three-phase overhead line air circuit breaker through a three-phase current transformer, and the fault simulation area is connected to the output end of the three-phase overhead line air circuit breaker; the low-voltage distribution cabinet also includes a three-phase voltage transformer and a three-phase air circuit breaker, and the three-phase voltage transformer is connected between the three-phase current transformer and the three-phase overhead line air circuit breaker through a three-phase air circuit breaker.

[0047] The low-voltage distribution cabinet 10 is used to detect the busbar three-phase voltage and outgoing line three-phase current under different overhead line fault types through a three-phase current transformer and a three-phase voltage transformer after receiving three-phase alternating current.

[0048] This embodiment ensures the safety and controllability of the test and the extraction of voltage and current parameters through a low-voltage distribution cabinet. The low-voltage distribution cabinet is provided with a three-phase linked three-phase fuse-type disconnector 1QS-FU with a voltage level of 380V. The parameters of the three-phase fuse-type disconnector 1QS-FU are preferably set to 250A. The use of the fuse-type disconnector 1QS-FU for line protection not only has the characteristics of a fuse and an disconnector, but also can overcome the problem that the fuse has only one-time breaking capability. The fuse can be replaced with the same specification and put into operation again. At the same time, since the fuse-type disconnector 1QS-FU itself has a good overcurrent protection effect, the fuse-type disconnector 1QS-FU is set in the low-voltage distribution cabinet in this embodiment to achieve a remote detection function.

[0049] In this embodiment, a three-phase overhead line air circuit breaker 2QF and a three-phase air circuit breaker 1QF connected to a voltage transformer are also provided in the low-voltage distribution cabinet. The three-phase overhead line air circuit breaker 2QF is set on the overhead line, and the three-phase air circuit breaker 1QF is used to connect the overhead line and three voltage transformers. Both circuit breakers are three-phase circuit breakers. The parameters of the three-phase overhead line air circuit breaker 2QF are preferably set to 100A, and the parameters of the PT (voltage transformer) three-phase air circuit breaker 1QF are preferably set to 1A. In this embodiment, the three-phase overhead line air circuit breaker 2QF is coordinated with the fuse-type disconnector 1QS-FU to connect the distribution transformer and the fault simulation area. The air switch, circuit breaker and disconnector selected in this embodiment can be replaced with equipment from different manufacturers to detect the breaking capacity under equipment fault conditions.

[0050] The parameters of the three-phase voltage transformer set in this embodiment are preferably set to JDG4-0.5 400 / 100V, which are placed in each of the three phases A, B, and C of the overhead line, respectively, with 1TV, 2TV, and 3TV respectively; at the same time, the parameters of the three-phase current transformer set in this embodiment are preferably set to 200 / 5A, which are placed in each of the three phases A, B, and C of the overhead line, respectively, with 1TA, 2TA, and 3TA respectively.

[0051] In one embodiment, the recording system 13 is used to detect whether there is arc breakdown based on the received busbar three-phase voltage and the outgoing line three-phase current, and obtain corresponding fault simulation information.

[0052] In this embodiment, the recording system 13 is used to collect voltage and current signals. The sampling rate of the oscilloscope used in the recording system is preferably set to 2.5GS / s, the bandwidth is preferably set to 500MHz, and the instrument frequency is preferably set to 10kHz. There are 6 fault recording channels, namely 380V bus voltage and three-phase current. At the same time, the recorder is set to multi-channel synchronous sampling. The recording system is connected to the three-phase voltage transformer and the three-phase current transformer of the low-voltage distribution cabinet. After the three-phase voltage transformer and the three-phase current transformer output the 380V bus three-phase voltage and the outgoing three-phase current respectively, the corresponding voltage waveform signal and current waveform signal are generated. This embodiment generates The voltage waveform signal and the current waveform signal are analyzed to determine whether there is an arc breakdown. Specifically, whether there is a sudden change in zero-sequence voltage and zero-sequence current is determined based on the voltage waveform signal and the current waveform signal, so as to detect whether the fault has started an arc based on the sudden change in zero-sequence voltage and zero-sequence current. If there is a sudden change in zero-sequence voltage and zero-sequence current, it means that there is an arc breakdown in the fault test; if not, there is a sudden change in zero-sequence voltage and zero-sequence current, which means that no arc has started in this test fault. It should be noted that the recording system in this embodiment can automatically record the voltage waveform signals and current waveform signals related to the three-phase fuse-type disconnector and the three-phase overhead line air circuit breaker after the operation, and can also manually start recording according to specific needs.

[0053] In this embodiment, the test system further includes a control system 12 connected to the input end of the low-voltage distribution cabinet, and the control system 12 is used to remotely control the operation of the three-phase fuse-type disconnector and the three-phase overhead line air circuit breaker in the low-voltage distribution cabinet.

[0054] The control system 12 is specifically used to remotely control the operation of the three-phase fuse-type disconnector in the low-voltage distribution cabinet when starting the overhead line fault simulation test, so as to boost the high-voltage side of the distribution transformer, and after the high-voltage side of the distribution transformer is boosted to a preset voltage value, remotely control the operation of the three-phase overhead line air circuit breaker and the three-phase air circuit breaker.

[0055] like Figure 3As shown, before the test begins, the test personnel manually set the test fault conditions that need to be simulated in advance. After setting the test conditions, the test personnel exit the test site, aim the outdoor camera at the test center site, enter the indoor control room, remotely control the three-phase fuse-type disconnector 1QS-FU to close, and then increase the voltage. The high-voltage side is increased to 10kV, and then remotely control the three-phase air circuit breaker 1QF to close, the three-phase voltage transformer is put into operation, and remotely control the three-phase overhead line air circuit breaker 2QF to close, that is, simulate the set fault condition type during normal operation. After the test is completed, the power is turned off and the test results are checked on site. The voltage and current signal waveforms recorded by the recording system are extracted to determine whether there are sudden changes in zero-sequence voltage and zero-sequence current in the voltage and current signal waveforms. If so, it is considered that there is arc breakdown in the fault test. If not and all test conditions are not completed, the overhead line model is replaced and the test is repeated. If an arc is generated, it is judged that this type of fault has a fire hazard under the set working conditions. If there are certain combustibles around, fire is likely to occur and more protection is required. If no arc is generated after replacing all lines and combustible conditions, it is judged that there is no fire hazard under such working conditions. It should be noted that the arc starting method meets the relevant requirements of the national standard GB / T 17467.

[0056] In this embodiment, the test conditions include a single-phase grounding fault test condition, a single-phase line break fault test condition, a two-phase short-circuit fault test condition, and a forest and pastoral area plant burning test condition.

[0057] Figure 4 The figure is a schematic diagram of a single-phase grounding fault test operating condition. In this embodiment, a simulation test is conducted for a single-phase grounding fault. Two insulating brackets with fixings are used to fix the overhead transmission line. The insulation in the middle of the overhead transmission line is removed to expose the conductor. Combustibles such as southern broadleaf fallen leaves, needles, and weeds are placed under the exposed overhead transmission line. The plate under the combustible is grounded, and one side of the overhead line is connected to the power system, while the other side is suspended. A lifting device is placed under the plate. A jack is preferably used as the lifting device to adjust the discharge distance between the line through the combustible and the ground. The single-phase grounding fault simulation test conducted in this embodiment can be used to simulate the occurrence of insulating discharge between the combustible and the ground when the insulation of the overhead line is damaged, and observe whether the discharge can cause the combustible to burn.

[0058] Figure 5The figure is a schematic diagram of a single-phase line break fault test condition. This embodiment conducts a simulation test for a single-phase line break fault. Two insulating brackets with fixtures are used to fix the overhead line. An adjustable transition resistor is connected to the overhead line between the insulating bracket and the tripod to adjust the breakdown fault current value through the adjustable transition resistor. One side of the overhead transmission line is connected to the power supply system. The end of the overhead transmission line is placed above a grounded plate. A tripod is used in the middle of the overhead transmission line to adjust the distance between the line cross-section and the plate. Moving the tripod to the left increases the distance and to the right decreases the distance. Combustible materials such as southern broadleaf fallen leaves, needles, and weeds are placed above the plate. The single-phase line break fault simulation test conducted in this embodiment can be used to simulate the occurrence of insulated discharge between the combustible material and the ground when the overhead line is broken to observe whether the discharge can cause the combustible material to burn.

[0059] Figure 6 Schematic diagram of a two-phase short-circuit fault test condition. This embodiment conducts a simulation test for a two-phase short-circuit fault. The three-phase overhead transmission line is laid normally, and a load is connected to the end of the three-phase overhead transmission line. The distance between the three-phase lines is d. In the power-off state, a two-phase short-circuit touch object is placed directly above phase A and phase B, where the two-phase short-circuit touch object is tree branches and leaves, etc., and then the power is turned on for the test. In this embodiment, the distance d of the three-phase overhead transmission line is adjustable, and the tree species can be replaced with branches of tree species unique to southern forestry. The two-phase short-circuit fault simulation test conducted in this embodiment can simulate a two-phase short-circuit fault caused by a tree branch touching a normally operating low-voltage overhead line to observe whether a breakdown discharge phenomenon occurs and whether the discharge can cause combustible combustion.

[0060] The test system provided in this embodiment can also simulate the test of high-temperature molten material splashing and igniting combustibles when a discharge fault occurs in an overhead transmission line. Two insulating brackets with fixtures are used to fix two test aluminum wires. One side of the insulating wire is connected to the power system, and the other side of the insulating wire is grounded. One of the insulating brackets is movable to adjust the length of the arc to increase the arc energy and make the experimental phenomenon more obvious. There is a plate on which combustibles are placed under the test aluminum wire. The type of combustibles can be replaced, such as southern broad-leaved fallen leaves, needles, weeds, etc. At the same time, there is a lifting equipment under the plate, and the lifting equipment is a jack. The height of the combustibles and the test aluminum wire can be adjusted by the jack. The specific test conditions are as follows: Figure 7 shown.

[0061] At the same time, the test system provided in this embodiment can also artificially set the transmission line in a burning environment to simulate the operation of the distribution network line in the forest and pastoral area affected by the fire. It can verify whether the transmission line will be broken due to the flame temperature during normal operation, and whether the dust between the lines will be generated by the burning of plants, which will make it easier to generate arcs. At the same time, the recording system can record the changes in voltage and current during the operation of the system, which is convenient for verification and analysis of the test results after the test. The specific test conditions are as follows: Figure 8 As shown, the test system provided in this embodiment can also simulate various other overhead line fault types. The specific test conditions refer to the above test settings and are not limited to the embodiments of the present invention, so they will not be described here one by one.

[0062] An embodiment of the present invention provides a low-voltage fire test system for forest and pastoral areas. The system realizes simulation tests of various overhead line fault types and plant combustion through a low-voltage distribution cabinet and a power supply system, a recording system and a fault simulation area connected to the low-voltage distribution cabinet. The recording system is used to obtain fault simulation information of the fault test, so as to effectively analyze the development of the short-circuit arc during the fault process in the later stage of the test, which is conducive to analyzing the development status of the electrical fire and greatly improves the authenticity and reliability of the low-voltage fire fault simulation in forest and pastoral areas.

[0063] In one embodiment, Figure 9 As shown, an embodiment of the present invention provides a low-pressure fire test method for forest and pastoral areas, the method comprising the following steps:

[0064] S1. In various types of overhead line fault simulation tests, simulate faults on overhead lines of different diameters or insulation characteristics according to pre-set test conditions;

[0065] S2. When simulating different types of overhead line faults, the three-phase voltage AC is output through the distribution transformer, and the busbar three-phase voltage and outgoing line three-phase current under different overhead line fault types are detected;

[0066] S3. Detect whether there is arc breakdown based on the received busbar three-phase voltage and the outgoing line three-phase current, and obtain corresponding fault simulation information.

[0067] It should be noted that the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of this application.

[0068] For the specific definition of a low-pressure fire test method in forest and pastoral areas, please refer to the above-mentioned definition of a low-pressure fire test system in forest and pastoral areas, which will not be repeated here. A person of ordinary skill in the art will appreciate that the various modules and steps described in conjunction with the embodiments disclosed in this application can be implemented in hardware, software, or a combination of both. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0069] An embodiment of the present invention provides a low-voltage fire test method in forest and pastoral areas. The method simulates different types of overhead line faults according to pre-set test conditions in a simulation test. When simulating different types of overhead line faults, a distribution transformer outputs alternating current with a three-phase voltage, and detects the busbar three-phase voltage and the outgoing line three-phase current under different overhead line fault types. The method detects whether there is arc breakdown based on the received busbar three-phase voltage and the outgoing line three-phase current, and obtains corresponding fault simulation information. Compared with the prior art, the present application can set different test conditions in a fault simulation area to simulate various fault types such as single-phase grounding, line break fault, and two-phase short circuit fault in the forest and pastoral area distribution network, as well as plant combustion tests. The method generates voltage waveform signals and current waveform signals through a recording system to analyze the development of the short-circuit arc during the fault process. The entire test process does not require the participation of too many test personnel, effectively improving detection efficiency. At the same time, it helps to analyze the causes of fires caused by distribution network faults in forest and pastoral areas, and reduces the probability of fires caused by distribution network faults in forest and pastoral areas. The present application has high practicality and is suitable for promotion and application.

[0070] The above-described embodiments merely represent several preferred implementations of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art could make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be based on the scope of protection of the claims.

Claims

1. A low-pressure fire test system for forest and pastoral areas, characterized in that: include: A low-voltage distribution cabinet and a power supply system, a wave recording system and a fault simulation area connected to the low-voltage distribution cabinet; The fault simulation area is used to simulate overhead line faults of various types according to pre-set test conditions in various overhead line fault simulation tests; The test conditions include single-phase grounding fault test conditions, single-phase line break fault test conditions, two-phase short circuit fault test conditions, and forest and pastoral plant burning test conditions; The single-phase ground fault test conditions are specifically as follows: An overhead transmission line is fixed using two insulating brackets with fixtures, and one side of the overhead transmission line is connected to a power system, while the other side of the overhead transmission line is suspended in the air. The insulation in the middle of the overhead transmission line is removed to expose the lower side of the overhead transmission line, so that combustibles are placed on the plate below the exposed overhead transmission line, wherein the plate is grounded, and a lifting device is placed below the plate to adjust the discharge distance between the overhead transmission line through the combustibles and the ground by the lifting device; The power supply system is used to output three-phase AC power to the low-voltage distribution cabinet through the distribution transformer when simulating different types of overhead line faults; The low-voltage distribution cabinet is used to detect the busbar three-phase voltage and the outgoing line three-phase current under different overhead line fault types through a three-phase current transformer and a three-phase voltage transformer after receiving the three-phase alternating current; The recording system is used to generate corresponding voltage waveform signals and current waveform signals based on the received bus three-phase voltage and the outgoing line three-phase current, and judge whether there is a sudden change in zero-sequence voltage and zero-sequence current based on the voltage waveform signals and current waveform signals, so as to detect whether there is an arc breakdown based on the sudden change in zero-sequence voltage and zero-sequence current, and obtain corresponding fault simulation information.

2. The low-pressure fire test system for forest and pastoral areas according to claim 1, characterized in that: The power supply system includes a single-phase power supply, a pole-mounted circuit breaker and a distribution transformer; The single-phase power supply is connected to the distribution transformer through the pole-mounted circuit breaker, and the distribution transformer is connected to the three-phase input terminal of the low-voltage distribution cabinet through the three-phase conductor of the overhead line.

3. The low-pressure fire test system for forest and pastoral areas according to claim 1, characterized in that: The low-voltage power distribution cabinet includes a three-phase fuse-type disconnector, a three-phase current transformer, and a three-phase overhead line air circuit breaker provided on the overhead line, wherein the three-phase fuse-type disconnector is connected to the three-phase overhead line air circuit breaker via the three-phase current transformer, and the fault simulation area is connected to the output end of the three-phase overhead line air circuit breaker; The low-voltage power distribution cabinet further includes a three-phase voltage transformer, which is connected between the three-phase current transformer and the three-phase overhead line air circuit breaker through a three-phase air circuit breaker.

4. The low-pressure fire test system for forest and pastoral areas according to claim 1, characterized in that: Also included is a control system connected to the input end of the low-voltage distribution cabinet; The control system is used to remotely control the operation of the three-phase fuse-type disconnector in the low-voltage distribution cabinet when starting the overhead line fault simulation test, so as to boost the voltage on the high-voltage side of the distribution transformer, and after the voltage on the high-voltage side of the distribution transformer is boosted to a preset voltage value, remotely control the operation of the three-phase overhead line air circuit breaker and the three-phase air circuit breaker.

5. The low-pressure fire test system for forest and pastoral areas according to claim 1, characterized in that: The single-phase line break fault test conditions are specifically as follows: Two insulating brackets with fixers are used to fix the overhead transmission line. One side of the overhead transmission line is connected to the power system, and the other side of the overhead transmission line is placed above the grounded electrode. A tripod is used in the middle of the overhead transmission line to adjust the distance between the cross section of the overhead transmission line and the electrode. An adjustable transition resistor is connected to the overhead line between the insulating bracket and the tripod to adjust the breakdown fault current value through the adjustable transition resistor, and combustibles are placed above the electrode.

6. The low-pressure fire test system for forest and pastoral areas according to claim 1, characterized in that: The two-phase short-circuit fault test conditions are specifically as follows: Connect the load at the end of the three-phase overhead transmission line, place the two-phase short-circuit touch objects directly above the A and B phases of the overhead transmission line in the power-off state, adjust the distance of the three-phase line and perform the power-on test.

7. The low-pressure fire test system for forest and pastoral areas according to claim 1, characterized in that: The fault simulation area also includes a monitoring system; The monitoring system is used to monitor the simulation test of the fault simulation area in real time.

8. A low-pressure fire test method in forest and pastoral areas, characterized in that: The method comprises the following steps: In various types of overhead line fault simulation tests, simulated tests are conducted on overhead line faults of different diameters or insulation characteristics according to pre-set test conditions; The test conditions include single-phase grounding fault test conditions, single-phase line break fault test conditions, two-phase short circuit fault test conditions, and forest and pastoral plant burning test conditions; The single-phase ground fault test conditions are specifically as follows: An overhead transmission line is fixed using two insulating brackets with fixtures, and one side of the overhead transmission line is connected to a power system, while the other side of the overhead transmission line is suspended in the air. The insulation in the middle of the overhead transmission line is removed to expose the lower side of the overhead transmission line, so that combustibles are placed on the plate below the exposed overhead transmission line, wherein the plate is grounded, and a lifting device is placed below the plate to adjust the discharge distance between the overhead transmission line through the combustibles and the ground by the lifting device; When simulating different types of overhead line faults, the distribution transformer outputs three-phase AC voltage, and detects the busbar three-phase voltage and outgoing line three-phase current under different overhead line fault types; Corresponding voltage waveform signals and current waveform signals are generated based on the received bus three-phase voltage and the outgoing three-phase current. Whether there is a sudden change in zero-sequence voltage and zero-sequence current is determined based on the voltage waveform signals and current waveform signals, so as to detect whether there is an arc breakdown based on the sudden change in zero-sequence voltage and zero-sequence current, and obtain corresponding fault simulation information.

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