CN114578168A

CN114578168A - Load device for bow net off-line test

Info

Publication number: CN114578168A
Application number: CN202210231875.7A
Authority: CN
Inventors: 杨轶轩; 刘尚合; 曹鹤飞; 刘卫东; 张明志; 李茜钰
Original assignee: Shijiazhuang Tiedao University
Current assignee: Shijiazhuang Tiedao University
Priority date: 2022-03-09
Filing date: 2022-03-09
Publication date: 2022-06-03

Abstract

The invention discloses a load device for bow net off-line test, comprising: the container, the container internal fixation has a plurality of U type pipe, the opening of U type pipe sets up, is provided with conducting solution in every U type pipe, respectively is provided with a conducting strip in the both ends of every U type pipe, the conducting strip is located conducting solution, and the upper end of every conducting strip is connected with a wire, makes after the wire between the adjacent U type pipe is connected the U type pipe is established ties or is connected in parallel together. The load device can adopt 3D printing, and is light in weight and easy to carry; the main material is water, so the cost is low; the load resistance value can be flexibly adjusted by using different numbers of U-shaped pipe connections.

Description

Load device for bow net off-line test

Technical Field

The invention relates to the technical field of train pantograph and catenary offline test devices, in particular to a load device for pantograph and catenary offline tests.

Background

An off-line test (called as a pantograph off-line test for short) between a pantograph and a contact network of a train is a test frequently carried out in rail transit scientific research and equipment manufacturing and is used for researching the mechanical property and the electromagnetic property of the pantograph.

The rated voltage of the contact net is 25KV, the current flowing through the pantograph under the conventional operation condition is 200A, and the contact net belongs to the high-voltage and high-current test condition. Because it is difficult to find a proper power supply and load device, a high-voltage low-current and low-voltage high-current testing device is often adopted in general scientific research work to respectively carry out bow net off-line characteristic research, and the effect of the bow net off-line characteristic research is different from the actual situation.

In a special environment with high voltage and large current test conditions, ideal test conditions can be provided, but at such high power, a load device is required to absorb electric energy and convert the electric energy into heat energy to be emitted into air. The load device generally uses a solid resistor made of alloy material, and the manufacturing of the resistor is performed by customizing after calculating the power factor, and the schematic diagram is shown in fig. 1.

The high voltage resistor used as the load for the bow net off-line discharge test needs to be able to withstand very high voltage and must have a very high resistance value. In order to prevent electric breakdown, an elongated substrate with high compressive strength is selected, the resistive film is made into a spiral belt type, and the voltage gradient along the length direction does not exceed 500V/cm, so that the two ends of the resistor are required to have enough length and enough monomer resistor serial partial pressure is required; meanwhile, a large amount of unit resistors are required to be connected in parallel to shunt current to ensure sufficient dissipation power. Therefore, the high-voltage high-power resistor is large in size, low in overload capacity, poor in heat dissipation, prone to resistor burning loss and incapable of recovering overload burning loss.

Disclosure of Invention

The invention aims to solve the technical problem of how to provide a load device for bow net off-line test, which has low cost and can flexibly adjust the load resistance value.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a load device for bow net off-line test, its characterized in that includes:

the container, the container internal fixation has a plurality of U type pipe, the opening of U type pipe sets up, is provided with conducting solution in every U type pipe, respectively is provided with a conducting strip in the both ends of every U type pipe, the conducting strip is located conducting solution, and the upper end of every conducting strip is connected with a wire, makes after the wire between the adjacent U type pipe is connected the U type pipe is established ties or is connected in parallel together.

Preferably, the equivalent cross-sectional area of the U-shaped pipe is 0.01 square meter.

Preferably, the U-shaped pipe is filled with a NaCl solution, and the concentration of NaCl is 0.8%.

Preferably, the effective length of the NaCl solution in the U-shaped pipe is 2 meters.

Preferably, the container is made of a transparent material.

The further technical scheme is as follows: and a U-shaped pipe fixing structure is formed at the bottom of the inner side of the container, and the U-shaped pipe is fixed in the container through the U-shaped pipe fixing structure.

The further technical scheme is as follows: and a wire fixing structure is formed on the outer side of the U-shaped pipe, and the position of the wire is fixed through the fixing structure, so that the position of the conducting strip is fixed to a certain height.

Preferably, the following components: the U-shaped pipe is provided with five rows and five columns, and the total number is twenty-five.

Preferably, the following components: the wire uses a copper wire.

Preferably: the transverse distance and the longitudinal distance between the U-shaped pipes are equal.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the liquid array load device comprises a plurality of U-shaped pipes, conductive solution is arranged in each U-shaped pipe, the U-shaped pipes are connected in series and in parallel through wires to form the liquid array load device, and the load resistance can be flexibly adjusted through the U-shaped pipes with different numbers, and the heat productivity is controlled through the water quantity. 3D printing can be adopted, and the device is light in weight and easy to carry; the main material is water, so the cost is low; the load resistance value can be flexibly adjusted by using different numbers of U-shaped pipe connections.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic diagram of a prior art solid state resistor;

FIG. 2 is a graph of water amount versus temperature rate of change in an embodiment of the present invention;

FIG. 3 is a schematic diagram of a test of the temperature-resistance variation relationship in an embodiment of the present invention;

FIG. 4 is a graph of temperature versus solution resistance according to an embodiment of the present invention;

FIG. 5 is a high voltage test chart in an embodiment of the present invention;

FIG. 6 is a schematic diagram of a tubular structure test in an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of the load device according to the embodiment of the present invention;

FIG. 8 is a schematic view of a part of the structure of the load device according to the embodiment of the present invention;

wherein: 1. a container; 2. a U-shaped pipe; 3. a conductive sheet; 4. and (4) conducting wires.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

As shown in fig. 7 to 8, an embodiment of the present invention discloses a load device for offline bow net test, including:

the container 1 may be made of a transparent material, a plurality of U-shaped tubes 2 are fixed in the container 1, preferably, the U-shaped tubes 2 may be fixed in the container 1 by a U-shaped tube fixing device (not shown in the figure) located at the bottom in the container 1, openings of the U-shaped tubes 2 are arranged upward, a conductive solution is provided in each U-shaped tube 2, preferably, an equivalent cross-sectional area of the U-shaped tube 2 is 0.01 square meter, a NaCl solution is provided in the U-shaped tube 2, a concentration of NaCl is 0.8%, an effective length of the NaCl solution in the U-shaped tube 2 is 2 meters, and it should be noted that the equivalent cross-sectional area, the concentration of the NaCl solution, and the effective length of the U-shaped tube 2 may be appropriately adjusted; two ends of each U-shaped pipe 2 are respectively provided with a conducting strip 3, the conducting strips 3 are positioned in a conducting solution, the upper end of each conducting strip 3 is connected with a wire 4, and the U-shaped pipes 2 are connected in series or in parallel after the wires between the adjacent U-shaped pipes 2 are connected. In addition, in order to ensure the position fixing of the conductive sheet, a wire fixing structure may be formed outside the U-shaped pipe 2, and the wire may be fixed in position by the fixing structure such that the position of the conductive sheet 3 is fixed to a certain height. Further preferably, the U-shaped tube 2 may be provided with twenty-five rows and five columns, and the wires 4 may be copper wires.

NaCl and water are used as main conductors, a special U-shaped pipe series-parallel connection structure meeting the bow net off-line power heat dissipation requirement is designed, and the load device meeting the test requirement, low in cost and easy to carry is developed.

Feasibility analysis

Voltage of a contact network: u is 25kV, pantograph current flows: I-200A, general test power-on time: t is 10 s;

the electric energy for heating water does work: w is 25 × 200 × 10 is 50MW UIt;

50MW is used for heating water, and the electric energy work of temperature change theoretical calculation all is used for heating water: Q-W-50 MW;

water heating energy formula: q ═ cm Δ t, where c is the specific heat capacity of purified water at one standard atmosphere, and c ═ 4.2 × 10³J/(kg. DEG C); m is the mass (kg) of purified water; Δ t is the temperature variation;

volume of 1L water: v is approximately equal to 1000cm³Density of water: rho is 1g/cm³And the mass of 1L of water: m ═ ρ · V ═ 1 kg;

taking the pure water with the mass of 1L, 2L, … and nL respectively, and obtaining a relation curve of the water quantity and the temperature change rate as follows: the temperature rise below 100 ℃ is shown in figure 2 by taking the pure water with the mass of 1L, 2L, … L and 2000L respectively. That is, the heat generation temperature in the bow net off-line test can be controlled to 30 ℃ or lower with a water volume of about 500L.

Temperature-resistance change relationship test:

45L liquid water + NaCl test, instrument apparatus: an alternating current power supply, a voltage regulator, a current loop, an oscilloscope, a thermometer, an iron plate and a plastic sorting box, wherein the experimental principle is shown in figure 3;

an experiment platform is set up according to an experiment principle diagram, a proper amount of NaCl solute is taken to be fully dissolved and mixed with water with the mass of 45L (the concentration is 0.8%), a pressure regulator is adjusted, and the maximum voltage value of 133V and the maximum current value of a loop at two ends of a NaCl solution of an oscilloscope are recorded.

Heating the NaCl solution through an iron plate, and recording the temperature of the NaCl solution, the maximum voltage value and the maximum current value of the oscilloscope in real time.

And calculating to obtain the resistance value of the NaCl solution.

And (4) experimental conclusion:

the resistance values at the respective temperatures calculated from the raw data are shown in the following table.

Time	Temperature (. degree.C.)	Maximum voltage (V)	Maximum current (A)	Solution resistance (omega)
					19:45:28	25.5	133	7.12	18.680
19:46:09	25.8	133	7.12	18.680
					19:47:40	25.9	133	7.20	18.472
19:49:22	26.1	133	7.20	18.472
					19:51:01	26.2	133	7.28	18.269
19:52:22	26.4	131	7.28	17.995
					19:53:51	26.6	131	7.36	17.799
19:55:46	26.8	131	7.36	17.799
					19:56:59	27	131	7.44	17.608
19:58:21	27.2	131	7.44	17.608
					19:59:50	27.4	131	7.44	17.608
20:01:22	27.5	131	7.52	17.420
					20:03:20	27.8	131	7.52	17.420
20:04:39	27.9	131	7.60	17.237
					20:06:08	28.1	131	7.68	17.057
20:05:50	28.3	131	7.68	17.057
					20:09:50	28.5	131	7.76	16.881
20:11:05	28.7	131	7.76	16.881
					20:12:30	28.9	131	7.76	16.881
20:14:08	29.1	131	7.84	16.709
					20:15:29	29.3	131	7.84	16.709
20:16:50	29.5	131	7.92	16.540
					20:18:30	29.7	131	8.00	16.375
20:19:30	29.9	131	8.00	16.375
					20:20:39	30.1	131	8.00	16.375

The curve of the temperature versus solution resistance is shown in fig. 4, where the curve is the actual resistance and the straight line is the fitted resistance.

From this, the relationship between the temperature change and the resistance change rate can be known.

By combining the tests, when the water volume of the load device reaches 500L and the temperature rises by 5 ℃ to 30 ℃, the resistance is changed into 2 omega, and the actual use requirement is met.

High-pressure test:

test apparatus: an alternating current power supply, a transformer, a control console, a protective resistor (10k omega multiplied by 3), an iron plate and a plastic sorting box, and the experimental principle is shown in figure 5.

The experimental steps are as follows: and (3) taking a proper amount of NaCl solute and 45L of water to be fully dissolved and mixed, and measuring the resistance value of the liquid to be 20 omega by using a pressure regulator and an oscilloscope. And sequentially adjusting the transformer control console to enable the effective values of the output voltage of the no-load secondary side of the transformer to be 1kV, 2kV and 3kV..

The experimental conclusion is that: the experimental raw data were obtained as shown in the table below.

Effective value of voltage (kV)	Effective value of current (A)
		1	1.08
2	3.48
		3	6.3
4	8.4
		5	9.3
6	10.99
		7	Tripping of control console

In the above test, the water temperature and the resistance did not change significantly.

And (3) testing a pipe-mounted structure:

test apparatus: alternating current power supply, transformer, control cabinet, wire, the long water pipe of 1m, the experimental principle is as shown in figure 6:

the experimental steps are as follows: a proper amount of NaCl solute and a water pipe with the length of 1m filled with water are fully dissolved and mixed (the concentration is 0.8%), an experiment platform is built according to an experiment principle diagram, and a transformer control console is sequentially adjusted to enable the effective value of the output voltage of the no-load secondary side of the transformer to be 1kV, 2kV and 3kV..

And (4) experimental conclusion: the experimental raw data were obtained as shown in the table below.

Effective value of voltage (kV)	Effective value of current (A)
		1	3.04
2	4.64
		3	7.49
4	10.57
		5	11.39
6	Tripping of control console

Adopt water pipe structure, can obtain the similar test effect with the water tank under the condition that reduces the water consumption.

At present, the load of a customized railway is 275 omega, when the concentration of NaCl is 0.8%, the resistivity of the customized railway is 1.25 omega, m, the equivalent sectional area of a U-shaped pipe is about 0.01 square meter, the equivalent length of the U-shaped pipe is about 2 meters, and the total resistance can reach more than 250 omega through calculation.

Claims

1. A load device for bow net off-line test, its characterized in that includes:

the container (1), container (1) internal fixation has a plurality of U type pipe (2), the opening of U type pipe (2) sets up, is provided with conductive solution in every U type pipe (2), respectively is provided with a conducting strip (3) in the both ends of every U type pipe (2), conducting strip (3) are located conductive solution, and the upper end of every conducting strip (3) is connected with a wire (4), makes behind the wire connection between the adjacent U type pipe (2) establish ties or parallelly connected together.

2. The load apparatus for offline bow net testing of claim 1, wherein: the equivalent sectional area of the U-shaped pipe (2) is 0.01 square meter.

3. The load apparatus for offline bow net testing of claim 1, wherein: NaCl solution is filled in the U-shaped pipe (2), and the concentration of NaCl is 0.8%.

4. The load apparatus for offline bow net testing according to claim 3, wherein: the effective length of the NaCl solution in the U-shaped pipe (2) is 2 meters.

5. The load apparatus for offline bow net testing of claim 1, wherein: the container (1) is made of transparent materials.

6. The load apparatus for offline bow net testing of claim 1, wherein: the bottom of the inner side of the container (1) is provided with a U-shaped pipe fixing structure, and the U-shaped pipe (2) is fixed in the container through the U-shaped pipe fixing structure.

7. The load apparatus for offline bow net testing according to claim 1, wherein: and a wire fixing structure is formed on the outer side of the U-shaped pipe (2), and the position of the wire is fixed through the fixing structure, so that the position of the conducting strip (3) is fixed to a certain height.

8. The load apparatus for offline bow net testing of claim 1, wherein: the U-shaped pipe (2) is provided with five rows and five columns, and the total number is twenty-five.

9. The load apparatus for offline bow net testing of claim 1, wherein: the lead (4) is a copper lead.

10. The load apparatus for offline bow net testing of claim 1, wherein: the transverse distance and the longitudinal distance between the U-shaped pipes (2) are equal.