Portable 10KV distribution transformer practical training device and experimental method thereof

Abstract

The invention provides a portable 10KV distribution transformer practical training device and an experiment method thereof. The portable 10KV distribution transformer practical training device comprises an assembly panel, a plurality of high-voltage pile heads, a tap switch, an oil level indicator and a plurality of low-voltage pile heads are fixed on the assembly panel, the low-voltage pile heads are connected through wires, and resistors are connected in series and in parallel in the high-voltage pile heads. The working principle of the distribution transformer is not changed, and the insulation resistance and direct current resistance measurement methods of the transformer are the same; a panel, a transformer body and high and low voltage bushings of the transformer made of existing light materials are the same as those in practice, resistors and windings are connected in series and in parallel in the transformer, and direct current resistance values are changed at different gears, so that students can be trained to perform actual operation in class conveniently, and the problems of high cost and poor training effect of an actual distribution transformer for training are solved. And the device can only be used in a practical training field, and the defect that hoisting equipment cannot move is overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power training equipment, and more specifically, to a portable 10KV distribution transformer training device and an experimental method thereof. Background Art

[0002] A distribution transformer is an electrical device used to transfer electrical energy from high voltage to low voltage. It is usually used in the distribution network in the power system to convert the electrical energy transmitted by the high-voltage transmission line into electrical energy suitable for low-voltage electrical equipment; the main function of the distribution transformer is to reduce the voltage to adapt to different power requirements and the working voltage of electrical equipment. The transformer uses the principle of magnetic induction to couple the high-voltage coil with the low-voltage coil through the iron core to achieve the conversion of electrical energy; the distribution transformer is usually composed of high-voltage and low-voltage side windings, an iron core and a cooling system. The high-voltage side winding is connected to the high-voltage power grid, and the low-voltage side winding is used to supply power to the low-voltage load. The iron core plays the role of concentrating the magnetic field and conducting the magnetic flux.

[0003] At present, in the distribution transformer training in the relevant technology, the training device used daily is the actual distribution transformer, and the cost of using the actual distribution transformer for training is relatively high. At the same time, due to the large size and heavy weight of the distribution transformer, it can only be used in the training site, and it is impossible to move the teaching according to local conditions, so that the training of personnel is restricted by the environment, which brings many inconveniences to the practical training teaching.

[0004] At the same time, due to the large size of the distribution transformer and the large resistance of the high-voltage winding, more windings are required, and there is a certain amount of residual charge after charging, which not only affects the stability of the measurement data, but also poses certain safety hazards. Summary of the invention

[0005] The purpose of the present invention is to provide a portable 10KV distribution transformer training device and an experimental method thereof, which can be conveniently moved and used during training operations, and can improve the safety of operation, and the measurement data is accurate and stable.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows: A portable 10KV distribution transformer training device and an experimental method thereof are characterized in that: it comprises an assembly panel, on which are fixed a plurality of high-voltage pile heads, a tap switch, an oil level indicator, and a plurality of low-voltage pile heads, each of the low-voltage pile heads is connected by a wire, and each of the high-voltage pile heads has a series-parallel resistor inside.

[0007] Improvement on the above technical solution: A box is provided at the bottom of the assembly panel, and two three-position toggle switches are also provided on the side of the box for practical training to set short circuit or ground fault.

[0008] Further improvement to the above technical solution: three high-pressure pile heads and four low-pressure pile heads are fixed on the assembly panel.

[0009] Further improvement of the above technical solution: the box at the bottom of the assembly panel is composed of an insulating plate, and resistors and windings are used inside.

[0010] An experimental method for a portable 10KV distribution transformer training device, the steps are as follows: 1) To perform DC resistance measurement: ① First, turn off the power, check the discharge, remove the lead and fix it, and remove the dirt on the oxide layer and the surface of the casing; ② High-voltage winding measurement, the resistance value of the high-voltage winding is greater than 1Ω, and the QJ23A single-arm bridge is used for daily work and examinations. The capacity of the three-phase distribution transformer is 100KVA. Taking the second gear as an example, the ratio arm selects X10-2; ③ Adjust the comparison arms in sequence, from high to low, until the bridge is leveled; 2) To measure the DC resistance of low-voltage windings, since the low-voltage resistance is less than 1Ω, a QJ44 double-arm bridge is used daily. When wiring, note that P1C1 and P2C2 are each a group. If the test line is four wires, the same low-voltage conductive rod P is at the bottom and C is at the top. For a distribution transformer with a capacity of 100KVA, the ratio arm is selected at X 0.1, then the small disk of the comparison arm is adjusted, and finally the large disk of the comparison arm is fine-tuned. After adjusting the sensitivity, fine-tune the balance of the stop bridge; 3) Conduct insulation resistance measurement: ① High to low and ground, use a 2500V megohmmeter, first short-circuit the high and low voltage piles respectively, ground the low voltage side, connect the E end of the megohmmeter to the low voltage, and the G end to the high voltage bushing shield; ② When the electronic meter voltage reaches 2500V and the rotation speed reaches 120-150 times per minute, the assistant connects the L line of the meter to the high-voltage side and keeps rotating at a constant speed without any pause. Read the 15S and 60S readings respectively. Then the assistant removes the L line on the high-voltage side and slowly stops rotating. Discharge in strict accordance with the regulations and record the data. ③ Use the same method to measure low to high and ground, use a 500V megohmmeter, read the 15S and 60S data, and finally calculate the absorption ratio R60 / R15. Path: high voltage: measure AB, AC, BC respectively, low voltage: ao, bo, co. Whether the path is qualified, use a 500V megohmmeter, gently shake half a circle when the pointer points to zero, the path is qualified; 4) After the gear is adjusted: only measure the high voltage, and the measurement method of the high voltage DC resistance is the same as that described in step 3); 5) Fault judgment: A three-speed fluctuation switch is installed on the side of the distribution transformer, which can be set for single-phase grounding and phase-to-phase short circuit faults. When a high-voltage or low-voltage single-phase grounding fault occurs, the megohmmeter has no resistance and is zero to the ground, and stops rotating immediately to prevent damage to the instrument. Beneficial Effects

[0011] The portable 10KV distribution transformer training device and experimental method described in the present invention do not change the working principle of the distribution transformer, and the insulation resistance and DC resistance measurement methods of the transformer are the same; the panel and body of the transformer are made of existing light materials, and the high and low voltage bushings are the same as the actual ones. The resistors and windings are connected in series and parallel inside to achieve different gears to change the DC resistance value, which can facilitate the training of trainees in the classroom. The actual distribution transformer is used for training. The cost is high and it can only be used in the training site without the disadvantage of being unable to move without lifting equipment. At the same time, the resistors are connected in series and parallel inside the present invention, so there is no safety risk caused by residual charge.

[0012] Therefore, the present invention can not only meet the daily training and practical exercises of employees, improve the efficiency of practical training, and effectively improve the skills of employees, but also avoid the safety problems caused by residual charge and the problem of unstable test values. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of a portable 10KV distribution transformer training device in an embodiment of the present invention; Figure 2 is a schematic diagram of the bottom structure of the assembly panel in an embodiment of the present invention; Figure 3 It is a circuit diagram of the resistor and winding used in the high voltage pile head in the embodiment of the present invention; Figure 4 It is a winding circuit diagram used in the low-voltage pile head in the embodiment of the present invention.

[0014] Figure 5 It is a schematic diagram of the DC resistance value on the low-voltage side of a 100KVA oil-immersed distribution transformer in the implementation method.

[0015] Figure 6 For the implementation method, the actual fault diagram in the work can be simulated for the practical training on the high voltage side of the distribution transformer.

[0016] Figure 7 It is a schematic diagram of the first, second and third gear DC resistance values ​​on the high voltage side of a 100KVA oil-immersed distribution transformer in the implementation method.

[0017] Explanation of the reference numerals: 1. Assembly panel; 2. High-pressure terminal; 3. Tap changer; 4. Oil level indicator; 5. Low-pressure terminal; 6. Three-position toggle switch; 7. Box.

[0018] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. DETAILED DESCRIPTION

[0019] The following is combined with Figures 1 to 4 The present invention is described in further detail.

[0020] It should be noted that the drawings are schematic and not to scale. For the sake of clarity and convenience, the relative sizes and proportions of the parts shown in the drawings are exaggerated or reduced in size, and any size is only illustrative and not restrictive. In addition, the same reference symbol is used for the same structure, element or accessory appearing in more than two figures to reflect similar features.

[0021] See also Figure 1-4 A portable 10KV distribution transformer training device and an experimental method thereof are shown, comprising an assembly panel 1, on which are fixed a plurality of high-voltage pile heads 2, a tap switch 3, an oil level indicator 4, and a plurality of low-voltage pile heads 5, each of the low-voltage pile heads 5 being connected by a wire, and each of the high-voltage pile heads 2 having a series-parallel resistor inside.

[0022] Preferably, a box body 7 is provided at the bottom of the assembly panel 1, and two three-position toggle switches 6 are also provided on the side of the box body 7 for practical training to set a short circuit or ground fault.

[0023] Preferably, three high-pressure pile heads 2 and four low-pressure pile heads 5 are fixed on the assembly panel 1 .

[0024] Preferably, the box body at the bottom of the assembly panel 1 is composed of an insulating plate, and resistors and windings are used inside.

[0025] See also Figure 5-7 As shown in the figure, an experimental method for a portable 10KV distribution transformer training device is shown in the figure, and the steps are as follows: 1) To perform DC resistance measurement: ① First, turn off the power, check the discharge, remove the lead and fix it, and remove the dirt on the oxide layer and the surface of the casing; ② High-voltage winding measurement, the resistance value of the high-voltage winding is greater than 1Ω, and the QJ23A single-arm bridge is used for daily work and examinations. The capacity of the three-phase distribution transformer is 100KVA. Taking the second gear as an example, the ratio arm selects X10-2; ③ Adjust the comparison arms in sequence, from high to low, until the bridge is leveled; 2) To measure the DC resistance of low-voltage windings, since the low-voltage resistance is less than 1Ω, a QJ44 double-arm bridge is used daily. When wiring, note that P1C1 and P2C2 are each a group. If the test line is four wires, the same low-voltage conductive rod P is at the bottom and C is at the top. For a distribution transformer with a capacity of 100KVA, the ratio arm is selected at X 0.1, then the small disk of the comparison arm is adjusted, and finally the large disk of the comparison arm is fine-tuned. After adjusting the sensitivity, fine-tune the balance of the stop bridge; 3) Conduct insulation resistance measurement: ① High to low and ground, use a 2500V megohmmeter, first short-circuit the high and low voltage piles respectively, ground the low voltage side, connect the E end of the megohmmeter to the low voltage, and the G end to the high voltage bushing shield; ② When the electronic meter voltage reaches 2500V and the rotation speed reaches 120-150 times per minute, the assistant connects the L line of the meter to the high-voltage side and keeps rotating at a constant speed without any pause. Read the 15S and 60S readings respectively. Then the assistant removes the L line on the high-voltage side and slowly stops rotating. Discharge in strict accordance with the regulations and record the data. ③ Use the same method to measure low to high and ground, use a 500V megohmmeter, read the 15S and 60S data, and finally calculate the absorption ratio R60 / R15. Path: high voltage: measure AB, AC, BC respectively, low voltage: ao, bo, co. Whether the path is qualified, use a 500V megohmmeter, gently shake half a circle when the pointer points to zero, the path is qualified; 4) After the gear is adjusted: only measure the high voltage, and the measurement method of the high voltage DC resistance is the same as that described in step 3); 5) Fault judgment: A three-speed fluctuation switch is installed on the side of the distribution transformer, which can be set for single-phase grounding and phase-to-phase short circuit faults. When a high-voltage or low-voltage single-phase grounding fault occurs, the megohmmeter has no resistance and is zero to the ground, and stops rotating immediately to prevent damage to the instrument.

[0026] Measuring range and standards: 1. Applicable to the DC resistance and insulation resistance measurement of oil-immersed distribution transformers and dry-type transformers.

[0027] Reference standard: Calculate the imbalance rate, formula: (η=Rmax-Rmin) / RpΧ100%; For three-phase distribution transformers with a capacity of 1600KVA or less, the line unbalance rate should be less than 2%, and the phase unbalance rate should be less than 4%. If this standard is exceeded, it means that the distribution transformer has a turn-to-turn short circuit or internal winding break.

[0028] This device does not change the working principle of the distribution transformer, and the insulation resistance and DC resistance measurement methods of the transformer are the same. The panel and body of the transformer are made of existing light materials, and the high and low voltage bushings are the same as the actual ones. The resistors and wires are connected in series and parallel inside to achieve different gears to change the DC resistance value. This can facilitate the training of students or employees in different scenarios, avoiding the disadvantages of the actual distribution transformer being used for training, which is high in cost and can only be used in training sites and is inconvenient to move.

[0029] It is worth noting that the appearance of this training device is the same as the actual distribution transformer, only the weight of the internal silicon steel sheet, transformer oil, and winding is eliminated. The overall weight is about 20Kg, and the cost is less than 500 yuan. The actual distribution transformer capacity is different, and the cost of each unit is at least 10,000 to 30,000 yuan. In addition, multiple units can be made and placed directly on the desk, so that students can listen to the lecture and start practical operation at the same time. The purpose is to enable students to master the use of single-arm and double-arm bridges and megohmmeters.

[0030] The standard parts used in the present invention can all be purchased from the market, and special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part adopt conventional means such as mature bolts, rivets, welding, etc. in the prior art. The machinery, parts and equipment all adopt conventional models in the prior art, and the circuit connection adopts the conventional connection method in the prior art, which will not be described in detail here.

[0031] In the drawings of the embodiments disclosed in the present invention, only the structures related to the embodiments disclosed in the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other.

[0032] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A portable 10KV distribution transformer training device and experimental method, characterized in that: The invention comprises an assembly panel (1), on which a plurality of high-voltage pile heads (2), a tap switch (3), an oil level indicator (4), and a plurality of low-voltage pile heads (5) are fixed, wherein the low-voltage pile heads (5) are connected to each other via a wire, and each high-voltage pile head (2) has a series-parallel resistor inside.

2. The portable 10KV distribution transformer training device and experimental method according to claim 1 are characterized in that: A box body (7) is provided at the bottom of the assembly panel (1), and two three-position toggle switches (6) are also provided on the side of the box body (7) for practical training to set a short circuit or ground fault.

3. The portable 10KV distribution transformer training device and experimental method according to claim 1 are characterized in that: Three high-pressure pile heads (2) and four low-pressure pile heads (5) are fixed on the assembly panel (1).

4. The portable 10KV distribution transformer training device and experimental method according to claim 1, 2 or 3, characterized in that: The box body at the bottom of the assembly panel (1) is composed of an insulating plate, and a resistor and a winding are used inside.

5. An experimental method for a portable 10KV distribution transformer training device, the steps are as follows: 1) To perform DC resistance measurement: ① First, turn off the power, check the discharge, remove the lead and fix it, and remove the dirt on the oxide layer and the surface of the casing; ② High-voltage winding measurement, the resistance value of the high-voltage winding is greater than 1Ω, and the QJ23A single-arm bridge is used for daily work and examinations. The capacity of the three-phase distribution transformer is 100KVA. Taking the second gear as an example, the ratio arm selects X10-2; ③ Adjust the comparison arms in sequence, from high to low, until the bridge is leveled; 2) To measure the DC resistance of low-voltage windings, since the low-voltage resistance is less than 1Ω, a QJ44 double-arm bridge is used daily. When wiring, note that P1C1 and P2C2 are each a group. If the test line is four wires, the same low-voltage conductive rod P is at the bottom and C is at the top. For a distribution transformer with a capacity of 100KVA, the ratio arm is selected at X 0.1, then the small disk of the comparison arm is adjusted, and finally the large disk of the comparison arm is fine-tuned. After adjusting the sensitivity, fine-tune the balance of the stop bridge; 3) Conduct insulation resistance measurement: ① High to low and ground, use a 2500V megohmmeter, first short-circuit the high and low voltage piles respectively, ground the low voltage side, connect the E end of the megohmmeter to the low voltage, and the G end to the high voltage bushing shield; ② When the electronic meter voltage reaches 2500V and the rotation speed reaches 120-150 times per minute, the assistant connects the L line of the meter to the high-voltage side and keeps rotating at a constant speed without any pause. Read the 15S and 60S readings respectively. Then the assistant removes the L line on the high-voltage side and slowly stops rotating. Discharge in strict accordance with the regulations and record the data. ③ Use the same method to measure low to high and ground, use a 500V megohmmeter, read the 15S and 60S data, and finally calculate the absorption ratio R60 / R15. Path: high voltage: measure AB, AC, BC respectively, low voltage: ao, bo, co. Whether the path is qualified, use a 500V megohmmeter, gently shake half a circle when the pointer points to zero, the path is qualified; 4) After the gear is adjusted: only measure the high voltage, and the measurement method of the high voltage DC resistance is the same as that described in step 3); 5) Fault judgment: A three-speed fluctuation switch is installed on the side of the distribution transformer, which can be set for single-phase grounding and phase-to-phase short circuit faults. When a high-voltage or low-voltage single-phase grounding fault occurs, the megohmmeter has no resistance and is zero to the ground, and stops rotating immediately to prevent damage to the instrument.

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