A transformer power receiving front cable cross prevention tester

Abstract

The utility model relates to the field of electrical debugging, concretely relates to a transformer receives the cable cross prevention tester before electricity, and the following technical scheme is proposed: battery, the output of battery is connected on the input of three -phase inverter, three -phase inverter is connected to the low voltage side incoming line end of transformer and the outgoing line end of transformer of transformer respectively through test line, the utility model accurately detects whether the cable exists the cross situation before electricity, removes the hidden danger in advance, prevents the short circuit, grounding and other failures caused by cable cross, avoids circuit breaker tripping and transformer burnout, guarantees the stable operation of power supply system, and also provides reliable security for operator.

Description

Technical Field

[0001] This utility model relates to the field of electrical commissioning, specifically to a tester for preventing cable crossover before a transformer is energized. Background Technology

[0002] In the operation and maintenance of power systems, transformers, as one of the core pieces of equipment, undertake the critical tasks of voltage transformation, power distribution, and transmission. Their stable and reliable operation directly affects the safety and efficiency of the entire power grid. With the continuous growth of electricity demand and the increasing complexity of power grid structures, large transformers are being used more and more widely in power systems. These transformers often possess high voltage levels and large capacity characteristics to meet the demands of long-distance, high-power power transmission. In practical engineering applications, to meet the current carrying capacity requirements of the high-voltage and low-voltage sides of the transformer, while considering the economy of cable laying and the rationality of spatial layout, the use of double or multi-section cable connections has become a common practice. Double or multi-section cable connections involve using two or more cables of the same specification in parallel to increase the total cross-sectional area of ​​the cables, thereby improving their current carrying capacity and ensuring the safe and stable operation of the transformer under rated load. While this connection method effectively solves the current carrying capacity problem, it also brings additional complexity and challenges to the transformer wiring work.

[0003] Especially during the preparation stage before the transformer receives power, the double or multiple connections of the high-voltage and low-voltage cables make wiring work particularly cumbersome. Due to the increased number of cables and denser terminal blocks, operators are highly susceptible to wiring errors due to negligence or improper operation. One of the most serious problems is the risk of cross-wiring. Cross-wiring not only disrupts the original electrical design logic of the transformer, leading to abnormal current paths, but can also cause serious faults such as phase-to-phase or phase-to-ground short circuits. A short circuit fault generates a huge short-circuit current in a very short time, far exceeding the rated carrying capacity of the transformer and cables, causing equipment overheating, insulation damage, and even catastrophic consequences such as fires or explosions. Simultaneously, the short-circuit current can cause a sudden drop in grid voltage, affecting the normal operation of other electrical equipment and causing economic losses and social impact. More seriously, if a short-circuit fault is not handled promptly and effectively, it may further expand the scope of the accident, threatening the safe and stable operation of the entire power supply system. Furthermore, wiring errors can also cause circuit breakers to malfunction, tripping under non-fault conditions and disconnecting normal power supply lines, causing unnecessary power outages. This not only affects users' electricity experience but may also cause irreversible damage to critical loads. Furthermore, frequent circuit breaker tripping accelerates wear and tear, reduces equipment lifespan, and increases maintenance costs. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a tester to prevent cable crossover before transformer power is received, thereby solving existing safety problems.

[0005] This utility model provides a transformer pre-energization cable cross-crossing tester, applied to transformers, comprising: A battery, the output of which is connected to the input of a three-phase inverter; A three-phase inverter, wherein the three-phase inverter is connected to the low-voltage side inlet terminal and the high-voltage side outlet terminal of the transformer respectively via test leads.

[0006] Optionally, the three-phase inverter is connected to the A, B, C and N input terminals of the low-voltage side of the transformer via test leads.

[0007] Optionally, the three-phase inverter is connected to the a, b, and c input terminals of the high-voltage side of the transformer via test leads.

[0008] Optionally, the three-phase inverter is connected via test leads to the insulating porcelain insulators at both the low-voltage side inlet and the high-voltage side outlet of the transformer.

[0009] Optionally, the terminals of the test leads are fixed to the insulating porcelain insulator at the low-voltage side inlet of the transformer by bolts.

[0010] Optionally, the terminals of the test leads are connected to the insulating porcelain insulator at the high-voltage side inlet of the transformer via a high-voltage connector.

[0011] Optionally, the positive terminal of the battery is connected to the positive input terminal of the three-phase inverter, and the negative terminal of the battery is connected to the negative input terminal of the three-phase inverter.

[0012] Optionally, a battery switch is provided on the battery.

[0013] Optionally, the cross-sectional area of ​​the test line is greater than 16 mm².

[0014] Optionally, the test lead is made of copper.

[0015] In summary, this application includes at least one of the following beneficial technical effects: This utility model includes a battery, the output end of which is connected to the input end of a three-phase inverter; A three-phase inverter, wherein the three-phase inverter is connected to the low-voltage side inlet terminal and the high-voltage side outlet terminal of the transformer respectively via test leads.

[0016] In summary, this utility model accurately detects whether cables are crossing before power is received, eliminates potential hazards in advance, prevents short circuits, grounding and other faults caused by cable crossings, avoids circuit breaker tripping and transformer burnout, ensures the stable operation of the power supply system, and also provides reliable safety protection for operators. Attached Figure Description

[0017] To better understand this invention, reference can be made to the embodiments shown in the following figures. Components in the figures are not necessarily drawn to scale, and related elements may be omitted, or in some cases the scale may have been enlarged to emphasize and clearly illustrate the novel features described herein. Additionally, as is known in the art, system components may be arranged differently. Furthermore, in the figures, the same reference numerals denote corresponding parts throughout several views.

[0018] Figure 1 A reference schematic diagram of a transformer pre-energization cable cross-crossing tester according to the present invention is shown; Explanation of the attached diagram labels: 1. Battery; 2. Three-phase inverter. Detailed Implementation

[0019] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.

[0020] The components of the present invention embodiments described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0021] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0024] Please see Figure 1 This utility model provides a transformer pre-energization cable cross-crossing tester, applied to transformers, comprising: Battery 1, the output terminal of which is connected to the input terminal of three-phase inverter 2; The three-phase inverter 2 is connected to the low-voltage side inlet and the high-voltage side outlet of the transformer via test leads.

[0025] This invention utilizes a battery 1 and a small three-phase inverter 2 to form a cable cross-connection prevention tester. A voltage is applied to the high-voltage side of the transformer to measure for cable cross-connection faults and grounding faults on the low-voltage side, making the transformer safer and more reliable during commissioning and ensuring the safety of operators. In power system operation, transformer energization is a high-risk operation. Traditional energization procedures typically rely on routine phase verification, but real-world examples show that even basic checks can lead to energization accidents due to incorrect phase sequence connections. By adding a specialized testing step using a cable cross-connection tester, secondary verification of electrical parameters on both the high-voltage and low-voltage sides can be achieved, effectively identifying potential hazards and improving the level of energization safety.

[0026] In some embodiments, please refer to Figure 1 The three-phase inverter 2 is connected to the A, B, C and N input terminals of the low-voltage side of the transformer via test lines.

[0027] The three-phase inverter 2, used as a testing device, is directly connected to phases A, B, and C, as well as the neutral line N, to accurately acquire key information such as voltage, current, and phase of each phase. By measuring whether the voltages of each phase are balanced, it is possible to determine whether there are problems such as inter-turn short circuits or wiring errors in the transformer windings. The neutral line N can detect potential grounding faults and other hidden dangers, thus ensuring the authenticity and reliability of the test results and reducing safety risks during the testing process.

[0028] The direct connection between the three-phase inverter 2 and the low-voltage side input terminal of the transformer makes the test circuit layout clearer and more standardized. Testers can clearly identify the phase corresponding to each test lead, avoiding misoperation caused by circuit confusion and effectively preventing electric shock accidents.

[0029] The connection interface between the three-phase inverter 2 and the low-voltage side input terminal of the transformer is standardized, allowing testers to quickly and accurately connect the test leads to the appropriate positions, significantly reducing preparation time before testing. Furthermore, this connection method facilitates various operations and adjustments during testing; testers can easily plug, unplug, and reconnect the test leads without complicated procedures, thus improving testing efficiency.

[0030] In some embodiments, please refer to Figure 1 The three-phase inverter 2 is connected to the a, b, and c input terminals of the high-voltage side of the transformer via test lines.

[0031] After the three-phase inverter 2 is connected to the input terminals a, b, and c, it can accurately measure the voltage and current of each phase to determine whether there are minor inter-turn short circuits or insulation aging problems. During the test, the three-phase inverter 2 can monitor the electrical parameters on the high-voltage side in real time. Once an abnormality is detected, such as overvoltage or overcurrent, it can quickly issue an alarm signal to remind the test personnel to take timely measures to prevent the accident from escalating further.

[0032] In some embodiments, please refer to Figure 1 The three-phase inverter 2 is connected to the insulating porcelain insulators of the low-voltage side inlet and the high-voltage side outlet of the transformer via test leads.

[0033] The low-voltage side inlet and high-voltage side outlet of the transformer are critical nodes for power transmission. Connecting the three-phase inverter 2 to the insulating porcelain insulators at these two points allows for precise measurement of key electrical quantities such as voltage and current on both the low-voltage and high-voltage sides. During the testing phase before the transformer is put into operation, acquiring data from both sides simultaneously allows for detailed analysis of the transformer's performance under different load conditions. Comparing voltage changes on the low-voltage and high-voltage sides can accurately determine whether cables are cross-connected, identify potential overload risks in advance, and prevent damage to the transformer due to prolonged overload operation.

[0034] Insulating porcelain insulators have excellent insulation properties. Connecting test leads to them can effectively prevent safety accidents caused by leakage or short circuits during testing. The test leads and high-voltage parts form a reliable insulation barrier, greatly reducing the risk of electric shock to test personnel.

[0035] In some embodiments, please refer to Figure 1 The terminals of the test leads are fixed to the insulating porcelain insulator at the low-voltage side inlet of the transformer by bolts.

[0036] Bolt fixing provides strong mechanical strength, firmly securing the terminals to the insulating porcelain insulator, effectively preventing accidental detachment and significantly reducing the probability of electrical accidents. Bolted terminals also offer excellent durability. During long-term transformer operation, various environmental factors such as temperature changes, humidity fluctuations, and vibrations can affect the connection. Ordinary connections may gradually loosen under these conditions, leading to poor contact. Bolt fixing, however, resists these environmental factors, maintaining connection stability. Even after prolonged operation, the terminals remain tightly connected to the low-voltage side of the transformer, ensuring continuous power transmission and improving the reliability of the power supply system.

[0037] In some embodiments, please refer to Figure 1 The terminals of the test leads are connected to the insulating porcelain insulator at the high-voltage side inlet of the transformer via a high-voltage connector.

[0038] High-voltage connectors possess excellent electrical performance, ensuring a low-resistance, stable electrical connection between the test leads and the high-voltage side input terminal of the transformer. When measuring voltage and current on the high-voltage side, a high resistance at the connection point will, according to Ohm's law, result in an additional voltage drop, leading to inaccurate voltage measurements. Simultaneously, the resistance will also cause deviations in current measurements. High-voltage connectors effectively reduce connection resistance, ensuring that test data accurately reflects the electrical parameters of the transformer's high-voltage side, providing a reliable basis for accurately assessing the transformer's performance and condition.

[0039] The high-voltage side of a transformer experiences high voltage, and ordinary connection methods may not be able to withstand such high voltage and electric field strength, easily leading to dangerous situations such as insulation breakdown and discharge. This can damage testing equipment. High-voltage connectors employ special insulating materials and structural designs, possessing high insulation strength and excellent arc resistance. They can effectively isolate current under high-voltage conditions, preventing leakage and short circuits, ensuring that testing can be conducted in a safe environment.

[0040] In some embodiments, please refer to Figure 1 The positive terminal of the battery 1 is connected to the positive input terminal of the three-phase inverter 2, and the negative terminal of the battery 1 is connected to the negative input terminal of the three-phase inverter 2.

[0041] As an energy storage device, battery 1 has a certain internal resistance, while the three-phase inverter 2, as a key energy conversion device, also has a corresponding input impedance. When the positive and negative terminals of battery 1 are directly connected to the corresponding input terminals of the three-phase inverter 2, the resistance loss in the connection line can be minimized. The simpler and more direct the connection line, the smaller the obstacle encountered by the current during transmission, thus enabling more electrical energy to be efficiently transferred from battery 1 to the three-phase inverter 2, improving the energy conversion efficiency of the entire system and reducing unnecessary energy waste.

[0042] In some embodiments, please refer to Figure 1 A battery switch is provided on the battery 1.

[0043] In some embodiments, please refer to Figure 1 The cross-sectional area of ​​the test line is greater than 16 mm².

[0044] When the cross-sectional area of ​​the test lead is greater than 16mm², it possesses a strong current-carrying capacity. In power systems, testing high-power equipment such as transformers and high-voltage motors generates significant currents during operation or testing. If the cross-sectional area of ​​the test lead is too small, a large amount of heat will be generated in the conductor when a large current passes through, causing the conductor temperature to rise rapidly. Excessive temperature not only accelerates the aging of the conductor insulation layer and reduces its lifespan, but may also cause insulation breakdown, leading to safety accidents such as short circuits. Test leads with a cross-sectional area greater than 16mm² effectively reduce resistance and heat generation, ensuring stable performance even under high current conditions, and safely and reliably completing testing tasks.

[0045] In some embodiments, please refer to Figure 1 The test line has a copper core.

[0046] Copper core test leads, with their high conductivity, allow current to flow smoothly, minimizing energy loss and ensuring stable current transmission during testing, thus laying the foundation for obtaining accurate and reliable test data.

[0047] In the testing field, test leads are frequently pulled, bent, and tangled. If the test lead material is brittle or easily deformed, it is prone to damage during use, affecting the normal progress of the test. Copper core test leads, on the other hand, can withstand a certain amount of external force and are not easily damaged by mechanical stress, thus having a longer service life.

[0048] The technical problem this invention aims to solve is to construct a cable cross-connection prevention tester using a battery 1 and a small three-phase inverter 2. Before normal use of the transformer, the wiring on the high-voltage and low-voltage sides of the transformer is inspected, thereby improving the overall safety and reliability of the transformer.

[0049] Preparation before testing: Before testing, personnel should be assigned to guard the transformer feeder cabinet and low-voltage incoming cabinet, and auxiliary equipment such as high-voltage megohmmeter, communication equipment, and safety warning ropes should be prepared. Prepare the transformer cable cross tester and perform a self-test to ensure accurate measurements.

[0050] The correct ratio of the transformer can be obtained using the formula K = E1 / E2. Note: K is the ratio of the transformer; E1 is the rated voltage value of the high-voltage side of the transformer; E2 is the rated voltage value of the low-voltage side of the transformer.

[0051] Taking a 10kV / 0.4kV transformer as an example: Assuming the voltage applied to the high-voltage side is 100V, the high-voltage and low-voltage sides of the transformer are correctly connected, with no short circuits or grounding issues, the high-voltage line voltages of the transformer are A-B 100V; A-C 100V; BC 100V. The low-voltage line voltages of the transformer are a-b 4V; b-c 4V; ca (4V). The low-voltage phase voltages of the transformer are an (2.3V); bn (2.3V); cn (2.3V).

[0052] If the measured values ​​are 0V for ab, 2.3V for ac, 2.3V for bc, 0V for an, 0V for bn, and 2.3V for cn, it can be determined that there is a crossover or short circuit fault in the ab phase cable connection. If the measured voltage value is incorrect or the switch trips, the cable needs to be verified.

[0053] The short-circuit voltage U can be obtained using the formula U / Ud, where U is the transformer's rated voltage and Ud is the short-circuit impedance. The short-circuit current can then be obtained using the formula V / 1V=Ie / X, where V is the short-circuit voltage, 1V is the applied voltage, Ie is the transformer's rated current, and X is the short-circuit current. The short-circuit current can be used to determine whether the switch tripping is caused by cable crossing.

[0054] Operating steps during testing: Step 1: Check if the circuit breaker of the high-voltage side feeder cabinet of the transformer is in the test position. If not, move it to the test position. Step 2: Check if the grounding switch on the high-voltage side feeder cabinet of the transformer is in the open position. If not, turn the grounding switch to the open position. Step 3: Check the insulation of the transformer's high-voltage cable circuit.

[0055] Step 4: After the insulation test is completed, discharge the high-voltage cable to prevent residual electricity from injuring people.

[0056] Step 5: Check if the low-voltage side incoming switch of the transformer is in the test position. If not, move it to the test position.

[0057] Step 6: Bring the transformer cable cross tester.

[0058] Step 7: Connect the wires to the insulating porcelain insulators on the high-voltage side (ABC) and the low-voltage side (abcn) of the transformer, respectively.

[0059] Step 8: Turn on the power switch of the cable crossover tester and check if the voltage is normal.

[0060] Step 9: After the test is completed, disconnect the cable cross tester and restore all equipment to its pre-test state.

[0061] The above specific embodiments are merely optional embodiments of this utility model. Based on the technical solution of this utility model and the related teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments. The above embodiments are possible examples of the implementation of this utility model and are only given to enable those skilled in the art to clearly understand the principles of this utility model. Those skilled in the art should understand that the above discussion of any embodiment is merely exemplary and is not intended to imply that the scope of the disclosure of the embodiments of this utility model includes claims limited to these examples. Under the overall concept of this utility model, the technical features of the above embodiments or different embodiments can also be combined with each other to produce many other variations of different aspects of the embodiments of this utility model as described above. For the sake of brevity, they are not provided in the specific embodiments. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this utility model should be included within the protection scope claimed by this utility model.

Claims

1. A transformer pre-energization cable cross-crossing tester, applied to a transformer, characterized in that, include: Battery (1), the output terminal of which is connected to the input terminal of three-phase inverter (2); The three-phase inverter (2) is connected to the low-voltage side inlet and the high-voltage side outlet of the transformer via test lines.

2. The transformer pre-energization cable cross-crossing tester according to claim 1, characterized in that, The three-phase inverter (2) is connected to the A, B, C and N input terminals of the low-voltage side of the transformer via test lines.

3. The transformer pre-energization cable cross-crossing tester according to claim 1, characterized in that, The three-phase inverter (2) is connected to the a, b and c input terminals of the high-voltage side of the transformer via test lines.

4. The transformer pre-energization cable cross-crossing tester according to claim 1, characterized in that, The three-phase inverter (2) is connected to the insulating porcelain insulators of the low-voltage side inlet and the high-voltage side outlet of the transformer via test leads.

5. The transformer pre-energization cable cross-crossing tester according to claim 4, characterized in that, The test leads are fixed to the insulating porcelain insulators at the low-voltage side inlet of the transformer by bolts.

6. The transformer pre-energization cable cross-crossing tester according to claim 4, characterized in that, The test leads are connected to the insulating porcelain insulator at the high-voltage side inlet of the transformer via a high-voltage connector.

7. The transformer pre-energization cable cross-crossing tester according to claim 1, characterized in that, The positive terminal of the battery (1) is connected to the positive input terminal of the three-phase inverter (2), and the negative terminal of the battery (1) is connected to the negative input terminal of the three-phase inverter (2).

8. The transformer pre-energization cable cross-crossing tester according to claim 1, characterized in that, A battery switch is provided on the battery (1).

9. The transformer pre-energization cable cross-crossing tester according to claim 1, characterized in that, The cross-sectional area of ​​the test line is greater than 16 mm².

10. The transformer pre-energization cable cross-crossing tester according to claim 1, characterized in that, The test leads are made of copper.

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