A phase detector with an automatic discrimination function

Abstract

The present invention relates to a phase detector, which includes a power supply device and a testing device. The power supply device includes a power supply group formed by two DC power supplies connected in series, and three connection terminals. Among them, the first connection terminal is connected to the negative electrode of the first DC power supply, the second connection terminal is connected to the positive electrode of the first DC power supply and the negative electrode of the second DC power supply, and the third connection terminal is connected to the positive electrode of the second DC power supply. The testing device includes four light-emitting diodes, two resistors, and three terminals. By designing the connection relationship of the three terminals and the four light-emitting diodes, then the three connection terminals are respectively connected to the three phases at one end of the cable under test, and the three terminals are respectively connected to the three phases at the other end of the cable under test. Compared with the prior art, the present invention can identify the connection situation of each terminal and connection terminal with only one test through the lighting conditions of the four light-emitting diodes.

Description

Technical Field

[0001] The present invention relates to a phase detector, and more particularly to a phase detector with an automatic discrimination function. Background Art

[0002] One of the most important items in the handover test of power transmission and distribution cables is phase checking. Cable phase checking is a work to check the phases at both ends of the cable before the cable is put into operation. During cable laying construction, phase-color tapes are wrapped around both ends of the cable. When installing the cable, the phase is confirmed through the phase-color tape and connected to electrical equipment (such as GIS, switchgear, busbar). If the phases at both ends of the cable are inconsistent, power transmission will fail, and in severe cases, equipment explosion will occur.

[0003] There are many cable phase-checking methods, all of which perform phase checking by applying voltage and current signals. Commonly used phase-checking methods use insulation resistance meters, multimeters, single-phase battery packs, etc. Among them, the most common methods are insulation resistance meters and phase detectors.

[0004] For example Figure 1 shows the method of using an insulation resistance meter. Figure 1 It includes the cable 1 to be measured, and single-phase matching is required. Taking the yellow phase as an example, the insulation resistance meter is used to apply a voltage of 5 kV at the test end, and the green and red phases are grounded at the opposite end of the test. The insulation resistance meter is used to boost the voltage of the yellow, green, and red phases respectively. When and only when the voltage of the yellow phase is 5 kV and the insulation is good, and the insulation resistance and voltage of the green and red phases are zero, it can be proved that the phase of the yellow phase is correct. Repeat the test for the green and red phases, and the test is completed.

[0005] Disadvantages of phase checking with an insulation resistance meter:

[0006] 1. Phase checking with an insulation resistance meter requires nine tests on the cable, and the test process is cumbersome.

[0007] 2. Phase checking with an insulation resistance meter requires reliable real-time communication. If one side is located in an underground substation, the test will be blocked.

[0008] 3. The test voltage of phase checking with an insulation resistance meter is high, posing a risk of injury.

[0009] 4. After each test with an insulation resistance meter, the three phases need to be discharged.

[0010] Figure 2 shows the basic phase detector method. The phase-checking method of the phase detector: Hang a 3V battery pack on the yellow and green phases at the opposite end of the cable, and hang the phase detector on the yellow and green phases at the test end. When and only when the connection is correct and the pointer of the phase detector deflects in the positive direction, it can be proved that the phases of the yellow and green phases are correct. Repeat the test for the green and red phases to be correct, and the test ends.

[0011] The disadvantages of this basic phase detector phase checking are as follows:

[0012] 1. The phase detector is a single-channel test instrument and can only test two items at a time.

[0013] 2. There is only a yellow-green two-color wire on the phase detector and the battery pack. If it is necessary to test the yellow-red and green-red phases, the wiring method needs to be agreed in advance, otherwise it will cause ambiguity.

[0014] 3. The pointer-type phase detector has relatively high requirements for the operation of testers and requires special training.

[0015] Regardless of which of the above phase detection methods is used, it has relatively high requirements for the cooperation on both sides of the cable and heavily relies on wireless communication (walkie-talkie, mobile phone). When the test point is located in an underground station, it will lead to poor communication and slow down the phase detection progress. Among them, the conventional phase detection method requires 9 operations, and the charging and discharging speed is slow and the time is long.

[0016] Those skilled in the art have also developed some upgraded phase detectors, but most of them are still inconvenient to operate, require multiple operations, or are too complex in structure and lack portability. Summary of the Invention

[0017] The purpose of the present invention is to provide a phase detector with an automatic discrimination function to overcome the defects existing in the above-mentioned prior art.

[0018] The purpose of the present invention can be achieved by the following technical solutions:

[0019] A phase detector includes a power supply device and a test device.

[0020] The power supply device includes a power supply group formed by connecting a first DC power supply and a second DC power supply in series, as well as a first terminal, a second terminal, and a third terminal. The positive electrode of the first DC power supply is connected to the negative electrode of the second DC power supply. The first terminal is connected to the negative electrode of the first DC power supply. The second terminal is connected to the positive electrode of the first DC power supply and the negative electrode of the second DC power supply. The third terminal is connected to the positive electrode of the second DC power supply.

[0021] The test device includes a first light-emitting diode, a second light-emitting diode, a third light-emitting diode, a fourth light-emitting diode, a first resistor, a second resistor, and a first terminal, a second terminal, and a third terminal. The first terminal is respectively connected to the negative electrode of the first light-emitting diode and the positive electrode of the third light-emitting diode. The second terminal is respectively connected to the negative electrode of the third light-emitting diode, the positive electrode of the fourth light-emitting diode, the positive electrode of the first light-emitting diode, and the negative electrode of the second light-emitting diode through the first resistor. The third terminal is respectively connected to the positive electrode of the second light-emitting diode and the negative electrode of the fourth light-emitting diode through the second resistor.

[0022] The first terminal, the second terminal, and the third terminal are respectively connected to the three phases at one end of the cable under test, and the first terminal, the second terminal, and the third terminal are respectively connected to the three phases at the other end of the cable under test. The connection conditions of each terminal and the wiring terminal are identified by the lighting conditions of four light-emitting diodes.

[0023] A first battery switch is provided between the second wiring terminal and the power supply group, and a second battery switch is provided between the third wiring terminal and the power supply group.

[0024] A first test switch is provided between the second terminal and the light-emitting diode, and a second test switch is provided between the third terminal and the light-emitting diode.

[0025] The first resistor and the second resistor are sliding rheostats.

[0026] After each light-emitting diode is connected in parallel with a voltage stabilizer diode, a resistor for voltage stabilization is connected in series to form a voltage-stabilized light-emitting diode unit.

[0027] The resistor for voltage stabilization is a carbon film resistor.

[0028] The voltages of the first DC power supply and the second DC power supply are equal.

[0029] The voltages of the first DC power supply and the second DC power supply are both less than 18V.

[0030] The voltages of the first DC power supply and the second DC power supply are both 3V or 3.3V.

[0031] The test device further includes an AND gate and a first indicator light. Two input terminals of the AND gate are respectively connected to the first light-emitting diode and the second light-emitting diode, and the output terminal is connected to the first indicator light.

[0032] A phase detector includes a power supply device and a test device.

[0033] The power supply device includes a power supply group formed by connecting a first DC power supply and a second DC power supply in series, a third resistor, a fourth resistor, and a first wiring terminal, a second wiring terminal, and a third wiring terminal. The positive pole of the first DC power supply is connected to the negative pole of the second DC power supply. The first wiring terminal is connected to the negative pole of the first DC power supply. The second wiring terminal is connected to the positive pole of the first DC power supply and the negative pole of the second DC power supply through the third resistor. The third wiring terminal is connected to the positive pole of the second DC power supply through the fourth resistor.

[0034] The test device includes a first light-emitting diode, a second light-emitting diode, a third light-emitting diode, a fourth light-emitting diode, as well as a first terminal, a second terminal, and a third terminal. The first terminal is respectively connected to the negative electrode of the first light-emitting diode and the positive electrode of the third light-emitting diode. The second terminal is respectively connected to the negative electrode of the third light-emitting diode, the positive electrode of the fourth light-emitting diode, the positive electrode of the first light-emitting diode, and the negative electrode of the second light-emitting diode. The third terminal is respectively connected to the positive electrode of the second light-emitting diode and the negative electrode of the fourth light-emitting diode;

[0035] The first connection terminal, the second connection terminal, and the third connection terminal are respectively connected to three phases at one end of the cable under test. The first terminal, the second terminal, and the third terminal are respectively connected to three phases at the other end of the cable under test. The connection conditions of each terminal and connection terminal are identified by the lighting conditions of the four light-emitting diodes.

[0036] A phase detector includes a power supply device and a test device,

[0037] The power supply device includes a power supply group formed by connecting a first DC power supply and a second DC power supply in series, a third resistor, a fourth resistor, as well as a first connection terminal, a second connection terminal, and a third connection terminal. The positive electrode of the first DC power supply is connected to the negative electrode of the second DC power supply. The first connection terminal is connected to the negative electrode of the first DC power supply. The second connection terminal is connected to the positive electrode of the first DC power supply and the negative electrode of the second DC power supply through the third resistor. The third connection terminal is connected to the positive electrode of the second DC power supply through the fourth resistor,

[0038] The test device includes a first light-emitting diode, a second light-emitting diode, a third light-emitting diode, a fourth light-emitting diode, a first resistor, a second resistor, as well as a first terminal, a second terminal, and a third terminal. The first terminal is respectively connected to the negative electrode of the first light-emitting diode and the positive electrode of the third light-emitting diode. The second terminal is respectively connected to the negative electrode of the third light-emitting diode, the positive electrode of the fourth light-emitting diode, the positive electrode of the first light-emitting diode, and the negative electrode of the second light-emitting diode through the first resistor. The third terminal is respectively connected to the positive electrode of the second light-emitting diode and the negative electrode of the fourth light-emitting diode through the second resistor;

[0039] The first connection terminal, the second connection terminal, and the third connection terminal are respectively connected to three phases at one end of the cable under test. The first terminal, the second terminal, and the third terminal are respectively connected to three phases at the other end of the cable under test. The connection conditions of each terminal and connection terminal are identified by the lighting conditions of the four light-emitting diodes.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1) The original 9 operations and phase detection tests are simplified to 1 time, greatly reducing the operation time and operation error, and reducing operation uncertainty;

[0042] 2) For the traditional insulation resistance meter test method, the process of charging the cable is avoided, and a small voltage of 6V is used for testing to avoid the danger of high-voltage injury; for the single-phase phase detector test method, the problem of repeating three times is avoided, and the three phases are directly phase-detected with an accuracy rate of 100%.

[0043] 3) The on-off combination of 4 light-emitting diodes is used to distinguish the phase condition, and the operation process is convenient. Description of the Drawings

[0044] Figure 1 It is a schematic diagram of phase detection in the existing insulation resistance meter method;

[0045] Figure 2 It is a schematic diagram under the existing basic phase detector method;

[0046] Figure 3 It is a schematic diagram of the structure of the present invention;

[0047] Figure 4 It is the display protection circuit of the embodiment of the present invention;

[0048] Figure 5 It is a schematic diagram of the logic judgment circuit of the present invention;

[0049] Figure 6(a) is a schematic diagram of the current with correct three phases;

[0050] Figure 6(b) is a schematic diagram of the current with AB phase inversion;

[0051] Figure 6(c) is a schematic diagram of the current with BC phase inversion;

[0052] Figure 6(d) is a schematic diagram of the current with AC phase inversion;

[0053] Figure 6(e) is a schematic diagram of the current when all three phases are reversed to BCA;

[0054] Figure 6(f) is a schematic diagram of the current when all three phases are reversed to CAB;

[0055] Among them: 1. Cable to be measured, 2. Power supply device, 3. Test device, 21. Battery switch, 31. Test switch, E1. First DC power supply, E2. Second DC power supply, D1. First light-emitting diode, D2. Second light-emitting diode, D3. Third light-emitting diode, D4. Fourth light-emitting diode, R1. First resistor, R2. Second resistor, R3. Third resistor, R4. Fourth resistor. Detailed Embodiment

[0056] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and gives the detailed implementation manners and specific operation procedures, but the protection scope of the present invention is not limited to the following embodiments.

[0057] A phase detector, as Figure 3 shown, includes a power supply device 2 and a test device 3.

[0058] The power supply device 2 includes a power supply group formed by connecting a first DC power supply E1 and a second DC power supply E2 in series, a third resistor R3, a fourth resistor R4, and a first terminal, a second terminal, and a third terminal. The positive electrode of the first DC power supply E1 is connected to the negative electrode of the second DC power supply E2. The first terminal is connected to the negative electrode of the first DC power supply E1. The second terminal is connected to the positive electrode of the first DC power supply E1 and the negative electrode of the second DC power supply E2 through the third resistor R3. The third terminal is connected to the positive electrode of the second DC power supply E2 through the fourth resistor R4.

[0059] The test device 3 includes a first light-emitting diode D1, a second light-emitting diode D2, a third light-emitting diode D3, a fourth light-emitting diode D4, and a first terminal, a second terminal, and a third terminal. The first terminal is respectively connected to the negative electrode of the first light-emitting diode D1 and the positive electrode of the third light-emitting diode D3. The second terminal is respectively connected to the negative electrode of the third light-emitting diode D3, the positive electrode of the fourth light-emitting diode D4, the positive electrode of the first light-emitting diode D1, and the negative electrode of the second light-emitting diode D2. The third terminal is respectively connected to the positive electrode of the second light-emitting diode D2 and the negative electrode of the fourth light-emitting diode D4.

[0060] The first terminal, the second terminal, and the third terminal are respectively connected to the three phases at one end of the cable under test 1, and the first terminal, the second terminal, and the third terminal are respectively connected to the three phases at the other end of the cable under test 1. The connection situation of each terminal and the terminal is identified by the lighting conditions of the four light-emitting diodes.

[0061] Specifically, the power supply device 2 can be a power supply box, and the test device 3 can be a test box. The power supply box has three leads of yellow, green, and red as the three terminals, corresponding to Figure 3 A, B, and C in, and the test box also has three leads of yellow, green, and red as the three terminals. When connecting to the cable under test 1, ensure reliable and stable connection.

[0062] As shown in FIG. 6(a), when the wiring is correct, that is, when the first terminal, the second terminal, and the third terminal are respectively connected to the first terminal, the second terminal, and the third terminal through the cable under test 1, D1 and D2 light up.

[0063] As shown in Figure 6(b), when AB is inverted, only D2 lights up. As shown in Figure 6(c), when BC is inverted, only D1 lights up. As shown in Figure 6(d), when AC is inverted, D1 and D4 light up. When all three phases are inverted to BCA, that is, when the first terminal, the second terminal, and the third terminal correspond to the second connection terminal, the third connection terminal, and the first connection terminal respectively, only D4 lights up. As shown in Figure 6(f), when all three phases are inverted to CAB, only D3 lights up.

[0064] As Figure 5 shown, since the lighting situation and the wiring situation present a two-way functional relationship, it is possible to know whether the wiring is correct and the error point from a single test of the lighting situation.

[0065] In other embodiments of the present application, R1 and R2 may not exist.

[0066] In other embodiments of the present application, R3 and R4 may not exist.

[0067] In another embodiment of the present application, the test device 3 is equipped with a self-checking function. When the self-checking switch is pressed, all 4 light-emitting diodes emit light. If there is no problem after repeated tests, proceed to the next step.

[0068] In other embodiments of the present application, a first battery switch may be provided between the second connection terminal and the power supply group, and a second battery switch may also be provided between the third connection terminal and the power supply group.

[0069] In other embodiments of the present application, the first resistor R1 and the second resistor R2 may be variable resistors.

[0070] In other embodiments of the present application, after each light-emitting diode is connected in parallel with a zener diode, a resistor for voltage stabilization is connected in series to form a voltage-stabilized light-emitting diode unit.

[0071] In other embodiments of the present application, the resistor for voltage stabilization may be a carbon film resistor.

[0072] The voltages of the first DC power supply E1 and the second DC power supply E2 are equal. In other embodiments of the present application, the voltages of the first DC power supply E1 and the second DC power supply E2 are both less than 18V. Preferably, the voltages of the first DC power supply E1 and the second DC power supply E2 are both 3V or 3.3V. In this way, a power supply group can be realized with 4 dry batteries or two AMS1117 modules. Both R3 and R4 are 0.1Ω, and the maximum values of R1 and R2 are 10kΩ.

[0073] In other embodiments of the present application, the test device 3 further includes an AND gate and a first indicator light. The two input terminals of the AND gate are respectively connected to the first light-emitting diode D1 and the second light-emitting diode D2, and the output terminal is connected to the first indicator light. Preferably, two indicator lights can be set, such as Figure 5As shown, a logic gate circuit chip is used to control the phase comparison indicator light. If the three phases are correct, the green light will be on; if there is an error, the red light will be on. Specifically, for the logic gate circuit, lights 1 and 2 are input items. When powered on, it is "1", and when not powered on, it is "2". When and only when the input is "1, 1", a high level is output to trigger the green light, indicating that the phase is correct. For the other five inputs, a low level is output to trigger the red light, indicating a phase error.

[0074] In other embodiments of the present application, as Figure 4 shown, there is also a display protection circuit.

Claims

1. A phase detector, characterized in that, It includes a power supply device and a testing device. The power supply device includes a power supply group formed by connecting a first DC power supply and a second DC power supply in series, as well as a first terminal, a second terminal, and a third terminal. The positive electrode of the first DC power supply is connected to the negative electrode of the second DC power supply. The first terminal is connected to the negative electrode of the first DC power supply. The second terminal is connected to the positive electrode of the first DC power supply and the negative electrode of the second DC power supply. The third terminal is connected to the positive electrode of the second DC power supply. Among them, the voltages of the first DC power supply and the second DC power supply are both less than 18V. The testing device includes a first light-emitting diode, a second light-emitting diode, a third light-emitting diode, a fourth light-emitting diode, a first resistor, a second resistor, as well as a first terminal, a second terminal, and a third terminal. The first terminal is respectively connected to the negative electrode of the first light-emitting diode and the positive electrode of the third light-emitting diode. The second terminal is respectively connected to the negative electrode of the third light-emitting diode, the positive electrode of the fourth light-emitting diode, the positive electrode of the first light-emitting diode, and the negative electrode of the second light-emitting diode through the first resistor. The third terminal is respectively connected to the positive electrode of the second light-emitting diode and the negative electrode of the fourth light-emitting diode through the second resistor. The first terminal, the second terminal, and the third terminal are respectively connected to three phases at one end of the cable under test. The first terminal, the second terminal, and the third terminal are respectively connected to three phases at the other end of the cable under test. The connection conditions of each terminal and the wiring terminal are identified by the lighting conditions of the four light-emitting diodes. A first battery switch is provided between the second terminal and the power supply group. A second battery switch is provided between the third terminal and the power supply group. A first test switch is provided between the second terminal and the light-emitting diode. A second test switch is provided between the third terminal and the light-emitting diode.

2. A phase detector according to claim 1, characterized in that, The first resistor and the second resistor are sliding rheostats.

3. A phase detector according to claim 1, characterized in that, After each light-emitting diode is connected in parallel with a voltage stabilizing diode, a resistor for voltage stabilization is connected in series to form a voltage-stabilized light-emitting diode unit.

4. A phase detector according to claim 3, characterized in that The resistor for voltage stabilization is a carbon film resistor.

5. A phase detector according to claim 1, characterized in that, The voltages of the first DC power supply and the second DC power supply are equal.

6. A phase detector according to claim 1, characterized in that, The testing device further includes an AND gate and a first indicator light. Two input terminals of the AND gate are respectively connected to the first light-emitting diode and the second light-emitting diode, and the output terminal is connected to the first indicator light.

7. A phase detector, characterized in that, It includes a power supply device and a testing device. The power supply device includes a power supply group formed by connecting a first DC power supply and a second DC power supply in series, a third resistor, a fourth resistor, as well as a first terminal, a second terminal, and a third terminal. The positive electrode of the first DC power supply is connected to the negative electrode of the second DC power supply. The first terminal is connected to the negative electrode of the first DC power supply. The second terminal is connected to the positive electrode of the first DC power supply and the negative electrode of the second DC power supply through the third resistor. The third terminal is connected to the positive electrode of the second DC power supply through the fourth resistor. Among them, the voltages of the first DC power supply and the second DC power supply are both less than 18V. The test device includes a first light-emitting diode, a second light-emitting diode, a third light-emitting diode, a fourth light-emitting diode, as well as a first terminal, a second terminal, and a third terminal. The first terminal is respectively connected to the negative electrode of the first light-emitting diode and the positive electrode of the third light-emitting diode. The second terminal is respectively connected to the negative electrode of the third light-emitting diode, the positive electrode of the fourth light-emitting diode, the positive electrode of the first light-emitting diode, and the negative electrode of the second light-emitting diode. The third terminal is respectively connected to the positive electrode of the second light-emitting diode and the negative electrode of the fourth light-emitting diode; The first connection terminal, the second connection terminal, and the third connection terminal are respectively connected to three phases at one end of the cable under test. The first terminal, the second terminal, and the third terminal are respectively connected to three phases at the other end of the cable under test. The connection conditions of each terminal and connection terminal are identified by the lighting conditions of the four light-emitting diodes; A first battery switch is provided between the second connection terminal and the power supply group, and a second battery switch is provided between the third connection terminal and the power supply group; A first test switch is provided between the second terminal and the light-emitting diode, and a second test switch is provided between the third terminal and the light-emitting diode.

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