Cable phase sequence discriminator

Abstract

The utility model relates to the technical field of electric power detection, in particular to a cable phase sequence discriminator, which comprises a transmitting unit, a receiving unit and a phase sequence discriminator, and is characterized in that the transmitting unit is provided with three output ends for connecting three phase lines of a cable, and the three output ends are used for transmitting three predetermined level signals; the receiving unit is connected to the other end of the cable; according to the phase sequence discriminator, direct current level signals are generated through the sending unit, the signals are accurately received through the receiving unit, the cable phase sequence discrimination function is achieved, the display mode of the receiving unit adopts the two-wire terminal design, an operator only needs to make contact with all phases of a cable once, and phase sequence discrimination can be completed; by means of the design, the operation procedure is greatly simplified, and the operation efficiency is improved; in addition, the phase sequence discriminator utilizes a direct-current level signal, the current always flows to a receiving end along a constant direction, and no advanced or delayed current exists in a circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of power detection, in particular to a cable phase sequence identification instrument. Background Art

[0002] With the rapid development of the economy and the continuous advancement of infrastructure construction, power cables play a vital role in connecting and transmitting electricity. The correct installation of power cables, especially the phase sequence identification of high and low voltage cables, has become a key link in ensuring the safe and stable operation of the power system.

[0003] In existing technology, phase sequence identification of high and low voltage cables typically relies on traditional bulb tests or multimeters with beep settings to short-circuit each phase. While these methods can accomplish phase sequence identification to a certain extent, they present numerous problems and limitations. First, they are susceptible to interference from radio waves, particularly in construction environments with poor communication signals, which can lead to inaccurate phase sequence identification. Second, these methods place high demands on the skill level of construction personnel. Inadequate skills often lead to errors in phase sequence identification, resulting in a waste of time, manpower, and material resources.

[0004] In addition, the traditional phase sequence identification method is complicated to operate and is not convenient for completing phase sequence identification quickly and accurately. This problem is particularly prominent in large-scale engineering projects. Therefore, a new high and low voltage cable phase sequence identification instrument is urgently needed to solve the above problems. Utility Model Content

[0005] The utility model aims to solve the shortcomings of the conventional phase sequence identification method in the prior art, such as complicated operation and inconvenience in completing phase sequence identification quickly and accurately, and proposes a cable phase sequence identification instrument.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] Design a cable phase sequence identification instrument, including:

[0008] A sending unit having three output terminals for connecting to three phase lines of the cable, wherein the three output terminals are used to send three predetermined level signals;

[0009] a receiving unit connected to the other end of the cable;

[0010] The receiving unit includes a test port for connecting to a phase line of a cable and a phase sequence identification circuit electrically connected to the test port, wherein the phase sequence identification circuit is used to receive three predetermined level signals.

[0011] Furthermore, the sending unit includes a three-phase signal generating circuit and an output signal display module connected to the output end of the three-phase signal generating circuit;

[0012] Wherein, the output end of the three-phase signal generating circuit is connected to the three phase lines of the cable through an output protection circuit.

[0013] Furthermore, the sending unit further includes:

[0014] A constant current source connected to an input end of the three-phase signal generating circuit;

[0015] and a power supply unit electrically connected to the constant current source.

[0016] Furthermore, the test port is connected to the phase sequence identification circuit through an input protection circuit, and the phase sequence identification circuit is also electrically connected to a phase sequence display module, wherein the input end of the phase sequence identification circuit is also connected to a power supply unit.

[0017] Furthermore, the power supply unit includes a boost and voltage stabilizing circuit, the input end of the boost and voltage stabilizing circuit is connected to an external AC charger through a lithium battery and a protection circuit, and a power display module is also connected to the lithium battery and the protection circuit.

[0018] Furthermore, the ground wires of the sending unit and the receiving unit are both connected to the armor layer of the cable under test.

[0019] The utility model provides a cable phase sequence identification instrument with the following beneficial effects: the phase sequence identification instrument generates DC level signals through a transmitting unit and uses a receiving unit to accurately receive these signals to realize the cable phase sequence identification function; the display mode of the receiving unit adopts a two-wire terminal design, so that the operator only needs to touch each phase of the cable once to complete the phase sequence identification. This design greatly simplifies the operation procedure and improves the operation efficiency;

[0020] In addition, this phase sequence identification instrument uses DC level signals, and the current always flows in a constant direction to the receiving end. There is no advance or delay current in the circuit, and no reactive power is generated. It can also store electricity and reduce interference such as line clutter and contact resistance. At the same time, it reduces the complexity of the circuit and reduces material and production costs. It can quickly and efficiently accurately identify the phase sequence characteristics of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural diagram of the utility model;

[0022] Figure 2 This is a principle block diagram of the sending unit of the present utility model;

[0023] Figure 3 This is a functional block diagram of the receiving unit of the present utility model;

[0024] Figure 4 This is a circuit diagram of a three-phase signal generating circuit of the utility model;

[0025] Figure 5 This is the constant current source circuit diagram of the utility model;

[0026] Figure 6 This is the circuit diagram of the phase sequence identification circuit of the present utility model.

[0027] In the figure: 1. Sending unit; 11. Three-phase signal generating circuit; 12. Output signal display module; 13. Output protection circuit; 14. Constant current source; 15. Boost voltage stabilization circuit; 16. Lithium battery and protection circuit; 17. AC charger; 18. Battery level display module; 2. Receiving unit; 21. Test port; 22. Phase sequence identification circuit; 23. Input protection circuit; 24. Phase sequence display module. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] Reference Figure 1-6 An embodiment of the present invention discloses a cable phase sequence identification instrument, which specifically includes:

[0030] The transmitting unit 1 has three output terminals for connecting to three phase lines of the cable, and the three output terminals are used to transmit three predetermined level signals;

[0031] a receiving unit 2, the receiving unit 2 being connected to the other end of the cable;

[0032] The receiving unit 2 includes a test port 21 for connecting to a cable phase line and a phase sequence identification circuit 22 electrically connected to the test port 21. The phase sequence identification circuit 22 is used to receive three predetermined level signals and determine the phase sequence of the current phase line by comparing the three predetermined level signals.

[0033] like Figure 2 As shown, in some embodiments, the transmitting unit 1 includes a three-phase signal generating circuit 11 and an output signal display module 12 connected to the output end of the three-phase signal generating circuit 11. The output signal display module 12 in this embodiment can be set as an LED light. The LED light indicates the output state by its on or off state;

[0034] Among them, the output end of the three-phase signal generating circuit 11 is connected to the three phase lines of the cable through the output protection circuit 13. Specifically, the output protection circuit 13 described in this embodiment is an anti-high-voltage reverse transmission protection circuit. In actual applications, an isolation transformer or ground wire protection can be used to avoid reverse power transmission. This method is a conventional method used by technicians in the field and will not be elaborated on here.

[0035] Specific as Figure 4 As shown in FIG, it is a schematic diagram of one phase circuit of the three-phase signal generating circuit 11 in this embodiment. The other two phase circuits are the same but the output parameters are different. Specifically, as shown in the figure, the output level is controlled by using a voltage regulating chip. In this way, in the three-phase circuit output, the output regulation of three predetermined levels can be completed by three voltage regulating chips.

[0036] like Figure 5 As shown, based on the above embodiment, the sending unit 1 in this embodiment further includes:

[0037] A constant current source 14 connected to the input end of the three-phase signal generating circuit 11;

[0038] and a power supply unit electrically connected to the constant current source 14 .

[0039] In the figure, the DC power supplied by the constant current source 14 is divided into three levels by the circuit. The constant current circuit is added to the instrument to prevent the battery and the boost voltage regulator circuit 15 of the instrument from being burned out due to a short circuit of the cable during the test or an accidental short circuit of the test clip after the instrument is turned on.

[0040] As shown in the figure, after the circuit is turned on, the battery voltage is boosted by the boost regulator circuit 15 and then input to the IN port. The gate of the field effect transistor BG1 in the constant current source is supplied with a potential vg by the W1 potentiometer. This connects the D and S poles of BG1, and the output voltage is sent to the phase detector circuit through R1.

[0041] When a cable or test clip is short-circuited, the output current increases. The increased voltage drop across R1 causes BG2 to conduct, pulling down the G-pole potential of BG1. This cuts off BG1, resulting in no voltage output at the OUT B+ terminal. Selecting the resistance values ​​of R1 and W1 in the circuit controls the protection circuit's startup level and protection current. Choosing the right R1 and W1 parameters ensures the circuit has the appropriate operating current and overcurrent protection level, protecting the instrument's battery and DC / DC circuit from damage.

[0042] When the short circuit is released, the voltage drop across R1 decreases, BG2 switches from on to off, the potential at the G terminal of BG1 increases, and BG1 returns to normal operation. The power supply OUT B+ output is normal.

[0043] Reference Figure 3Furthermore, in this embodiment, the test port 21 is connected to the phase sequence identification circuit 22 through an input protection circuit 23, and the phase sequence identification circuit 22 is also electrically connected to a phase sequence display module 24, wherein the input end of the phase sequence identification circuit 22 is also connected to a power supply unit. Specifically, in this embodiment, the input protection circuit 23 is also configured as a high-voltage reverse transmission protection circuit. In actual applications, an isolation transformer or ground wire protection can be used to avoid reverse power transmission. This method is a conventional method used by technicians in the relevant field and will not be elaborated on here.

[0044] Specific as Figure 6 As shown, the phase sequence identification circuit 22 described in this embodiment is specifically shown in the figure. When the test end contacts the signal sent by the cable, the signal is sent to the three comparator circuits A / B / C to compare the sent level with the reference phase sequence level. The comparator that meets the conditions outputs a high level. If the A phase level comparison is successful, the A phase comparator outputs a high level to drive BG1 to work, and BG1 drives the yellow LED light to light up, indicating that the phase A cable is in phase A. At the same time, a voice broadcast can also be used for prompting.

[0045] The three-phase reference level is generated based on the preset level sent by the original TX transmitter. The reference source is added to the receiving part to accurately compare the external signal.

[0046] When the signal is compared with the B-phase reference and meets the conditions, the B-phase comparator outputs a high level, driving BG2 to drive the green LED light-emitting tube for phase indication. At the same time, the high level is output to drive BG4 to work, driving IC1 to work. IC1 outputs a low level to lock the A-phase comparator to prevent false triggering.

[0047] Similarly, when the C phase signal is detected, the C phase comparator works and is driven in the same way as the A / B phase. When the C phase comparator works, it also drives BG5 to work. BG5 drives IC2 to lock the A / B phase of the comparator. This ensures that the A / B comparator is locked when the C phase signal is detected to prevent misjudgment of interference signals and ensure that only one group of lights is on.

[0048] It should be noted that the power supply unit described in this embodiment includes a boost and voltage regulator circuit 15. Of course, the boost and voltage regulator circuit 15 described in this embodiment is a DC-DC voltage regulator circuit. Its specific circuit structure is conventional and will not be described in detail here. The input end of the boost and voltage regulator circuit 15 is connected to an external AC charger 17 through a lithium battery and protection circuit 16. The lithium battery and protection circuit 16 is also connected to a power display module 18. The lithium battery and protection circuit 16 and the power display module 18 can be configured as a battery protection board and an indicator light, respectively. Their structure is a conventional technical solution, so it will not be described in detail here.

[0049] Of course, in order to conveniently ground the instrument during the detection process, the ground wires of the sending unit 1 and the receiving unit 2 in this embodiment are both connected to the armor layer of the cable under test.

[0050] In summary, the present phase sequence identification instrument generates DC level signals through the transmitting unit 1 and uses the receiving unit 2 to accurately receive these signals to realize the phase sequence identification function of the cable. The display mode of the receiving unit 2 adopts a two-wire terminal design, so that the operator only needs to touch each phase of the cable once to complete the phase sequence identification. This design greatly simplifies the operation procedure and improves the operating efficiency.

[0051] In addition, this phase sequence identification instrument uses DC level signals to quickly and efficiently solve the difficult problem of accurately identifying the cable phase sequence. Compared with traditional methods, it avoids radio wave interference, reduces the error rate of phase sequence identification, and improves the accuracy and reliability of identification.

[0052] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A cable phase sequence identification instrument, characterized in that: include: A sending unit (1) has three output terminals for connecting to three phase lines of a cable, the three output terminals being used to send three predetermined level signals; A receiving unit (2), the receiving unit (2) being connected to the other end of the cable; The receiving unit (2) comprises a test port (21) for connecting to a cable phase line and a phase sequence identification circuit (22) electrically connected to the test port (21), wherein the phase sequence identification circuit (22) is used to receive three predetermined level signals.

2. A cable phase sequence identification instrument according to claim 1, characterized in that: The sending unit (1) comprises a three-phase signal generating circuit (11) and an output signal display module (12) connected to the output end of the three-phase signal generating circuit (11); The output end of the three-phase signal generating circuit (11) is connected to the three phase lines of the cable through an output protection circuit (13).

3. A cable phase sequence identification instrument according to claim 2, characterized in that: The sending unit (1) further comprises: A constant current source (14), the constant current source (14) being connected to an input end of the three-phase signal generating circuit (11); and a power supply unit electrically connected to the constant current source (14).

4. A cable phase sequence identification instrument according to claim 1, characterized in that: The test port (21) is connected to the phase sequence identification circuit (22) via an input protection circuit (23); the phase sequence identification circuit (22) is also electrically connected to a phase sequence display module (24); and the input end of the phase sequence identification circuit (22) is also connected to a power supply unit.

5. A cable phase sequence identification instrument according to claim 3 or 4, characterized in that: The power supply unit comprises a boost and voltage stabilizing circuit (15), an input end of the boost and voltage stabilizing circuit (15) is connected to an external AC charger (17) via a lithium battery and a protection circuit (16), and a power display module (18) is also connected to the lithium battery and the protection circuit (16).

6. A cable phase sequence identification instrument according to claim 1, characterized in that: The ground wires of the sending unit (1) and the receiving unit (2) are both connected to the armor layer of the cable under test.

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