Grounding impedance measuring device for fault loop

Abstract

The utility model relates to the technical field of electrical testing, and particularly discloses a grounding impedance measuring device for a fault loop, which comprises a box body, a resistor A, a resistor B and a resistor C which are arranged in the box body, and a circuit interface, a power supply assembly, an air switch A, an air switch B, an air switch C, an air switch D, a voltmeter and an ampere meter which are arranged on the surface of the box body. According to the technical scheme of the utility model, a high-precision voltmeter and a high-precision ampere meter are adopted through an impedance voltage drop method and on the basis of a conventional laboratory method, and three groups of resistors are adopted for respectively measuring and averaging so as to improve the measurement precision. The weak grounding link in the circuit system can be found by testing the impedance value of the loop, and the unqualified loop incoming line is corrected, so that the situation of electric shock danger caused by no action of a protection electric appliance due to too small current of the grounding fault loop is completely eradicated, and the electricity utilization safety is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electrical testing, in particular to a device for measuring ground impedance of a fault loop. Background Art

[0002] According to the requirements of GB / 50303-2015, when the overcurrent protection device in the terminal power circuit of the low-voltage complete distribution cabinet and distribution box (panel) is also used as fault protection, the ground fault loop impedance should be measured at the end of the loop, and the impedance should be less than 2 / 3*U0 / Ia; the specification only requires the measurement of impedance, and the relevant detection specifications only have laboratory measurement methods, which cannot be applied in engineering. Appendix B gives two test methods: impedance voltage drop method and current clamp method. There is no dedicated ground impedance measuring instrument on the market. The specification GB / T16895.23-2012 / IEC60364-6:2006 Low Voltage Electrical Installation Part 6: Appendix B only gives two test methods: impedance voltage drop method and current clamp method, which are difficult to apply at the construction site. Therefore, we propose a ground impedance measurement device for fault circuits. Utility Model Content

[0003] The utility model aims to provide a device for measuring the ground impedance of a fault loop, which solves the problem raised in the background technology.

[0004] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a device for measuring the ground impedance of a fault loop, comprising a box, a resistor A, a resistor B, and a resistor C arranged inside the box, and a line interface, a power supply component, an air switch A, an air switch B, an air switch C, an air switch D, a voltmeter, and an ammeter are arranged on the surface of the box;

[0005] The line interface includes the live wire L interface, the neutral wire N interface and the ground wire PE interface;

[0006] Resistor A is connected in series with air switch B, resistor B is connected in series with air switch C, resistor C is connected in series with air switch D, resistor A, resistor B, and resistor C are connected in parallel with each other, the common end of resistor A, resistor B, and resistor C connected in parallel is connected to one end of the current measurement point of the ammeter, and the other end of the current measurement point of the ammeter is connected to the ground wire PE interface, the power supply of the voltmeter and the ammeter is supplied by the live wire L interface and the neutral wire N interface at the lower port of the main air switch, the four outlet lines of the lower port of air switch A are respectively connected to the upper ports of air switch B, air switch C, air switch D and the voltage measurement point of the voltmeter, and the main air switch is connected in series between the live wire L interface and the neutral wire N interface.

[0007] As a preferred implementation of the technical solution of the present application, a heat dissipation structure is arranged on both sides of the interior of the box, the heat dissipation structure includes a porous cover arranged on both sides of the box, a fan for heat dissipation is arranged inside the porous cover, and the power supply component includes a battery for supplying electric energy to the fan and a switch for controlling the start and stop of the fan.

[0008] As a preferred implementation of the technical solution of the present application, one end of the voltmeter and one end of the ammeter are both connected to the ground wire PE interface through a ground wire.

[0009] As a preferred implementation of the technical solution of the present application, the live wire L interface, the neutral wire N interface and the ground wire PE interface are vertically distributed on the surface of the box from top to bottom.

[0010] As a preferred implementation scheme of the technical solution of the present application, the power supply assembly, air switch A, air switch B, air switch C, and air switch D are horizontally distributed on the surface of the box from left to right.

[0011] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0012] The technical solution of the present application adopts a high-precision voltmeter and a high-precision ammeter through an impedance voltage drop method and on the basis of a conventional laboratory method, three groups of resistors are used for separate measurements and the average is taken to improve the measurement accuracy, and all test instruments are integrated in a portable test box to improve portability. The present invention solves the problem of fault loop impedance test and measurement. By testing the loop impedance value, the weak grounding link in the circuit system can be found, and the unqualified loop incoming line can be corrected, eliminating the situation where the protective electrical appliance does not operate due to the current of the ground fault loop being too small, causing the risk of electric shock, thereby improving electricity safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0014] Figure 1 It is a three-dimensional diagram of a fault loop ground impedance measuring device;

[0015] Figure 2 This is a diagram showing the distribution of components inside a fault loop ground impedance measurement device;

[0016] Figure 3 The utility model discloses a circuit connection diagram of a device for measuring ground impedance of a fault loop.

[0017] In the figure: 1. Main air switch; 2. Air switch A; 3. Voltmeter; 4. Ammeter; 5. Resistor A; 6. Resistor B; 7. Resistor C; 8. Air switch B; 9. Air switch C; 10. Air switch D; 11. Heat dissipation structure; 12. Box; 13. Power supply assembly. DETAILED DESCRIPTION

[0018] 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 of the embodiments.

[0019] Embodiment 1, as Figure 1-3 As shown, the utility model provides a technical solution: a device for measuring the ground impedance of a fault loop, comprising a box 12, a resistor A5, a resistor B6, and a resistor C7 arranged inside the box 12, and a line interface, a power supply component 13, an air switch A2, an air switch B8, an air switch C9, an air switch D10, a voltmeter 3, and an ammeter 4 are arranged on the surface of the box 12;

[0020] The line interface includes a live wire L interface, a neutral wire N interface and a ground wire PE interface, which are vertically distributed on the surface of the box 12 from top to bottom, and the power supply component 13, the air switch A2, the air switch B8, the air switch C9, and the air switch D10 are horizontally distributed on the surface of the box 12 from left to right;

[0021] Resistor A5 is connected in series with air switch B8, resistor B6 is connected in series with air switch C9, resistor C7 is connected in series with air switch D10, resistor A5, resistor B6, and resistor C7 are connected in parallel with each other, the common end of resistor A5, resistor B6, and resistor C7 connected in parallel is connected to one end of the current measurement point of ammeter 4, and the other end of the current measurement point of ammeter 4 is connected to the ground wire PE interface, the power supply of voltmeter 3 and ammeter 4 is connected by the live wire L interface and the neutral wire N interface at the lower port of the main air switch 1, the four outlet lines at the lower port of air switch A2 are respectively connected to the upper ports of air switch B8, air switch C9, air switch D10 and the voltage measurement point of voltmeter 3, and the main air switch 1 is connected in series between the live wire L interface and the neutral wire N interface.

[0022] In a specific embodiment of the present utility model, the range of the voltmeter 3 is 300V, the resolution is 10mV, the range of the ammeter is 3A, the resolution is 1mA, the resistance of resistor A5, resistor B6, and resistor C7 is 200Ω, one end of the red, blue, and yellow measuring wires are inserted into the L, N, and PE ports on the test box, and the other ends are connected to the live wire, neutral wire, and ground wire of the circuit under test, and the power switch, the main air switch 1, and the air switch A2 are closed in turn, and the voltage value reading of the voltmeter 3 at this time is recorded as U0, and the air switch B8 is closed, and the voltage value reading U1 of the voltmeter 3 and the current value reading I1 of the ammeter 4 are recorded at this time, and the air switch C9 and the air switch D10 are closed in turn, and the voltage value readings U2 and U3 of the voltmeter 3 and the current value readings of the ammeter 4 are read out in turn as I2 and I3, and the measurement results RX=(UO-Un) / In are calculated three times according to the measured values, and the average value of the three measurements is taken as the final impedance value.

[0023] In the preferred technical solution, a heat dissipation structure 11 is arranged on both sides of the box body 12. The heat dissipation structure 11 includes a porous cover arranged on both sides of the box body 12. A fan for heat dissipation is arranged inside the porous cover. The power supply component 13 includes a battery for supplying electric energy to the fan and a switch for starting and stopping the fan. The fan cooperates with the porous cover to quickly dissipate the heat inside the box body 12.

[0024] In the preferred technical solution, one end of the voltmeter 3 and one end of the ammeter 4 are connected to the ground wire PE interface through a ground wire, and grounding can improve the safety of the use of the voltmeter 3 and the ammeter 4.

[0025] In summary, this embodiment uses a high-precision voltmeter and a high-precision ammeter on the basis of conventional laboratory methods, and uses three groups of resistances to measure and take the average value to improve the measurement accuracy, thereby improving the measurement accuracy. The instrument is integrated in a box, which improves portability.

Claims

1. A device for measuring the ground impedance of a fault loop, characterized in that: The invention comprises a box (12), a resistor A (5), a resistor B (6), and a resistor C (7) arranged inside the box (12); a line interface, a power supply component (13), an air switch A (2), an air switch B (8), an air switch C (9), an air switch D (10), a voltmeter (3), and an ammeter (4) are arranged on the surface of the box (12); The line interface includes a live line L interface, a neutral line N interface and a ground line PE interface; The resistor A (5) is connected in series with the air switch B (8), the resistor B (6) is connected in series with the air switch C (9), and the resistor C (7) is connected in series with the air switch D (10). The resistor A (5), the resistor B (6), and the resistor C (7) are connected in parallel with each other. The common end of the resistors A (5), B (6), and C (7) connected in parallel is connected to one end of the current measurement point of the ammeter (4), and the other end of the current measurement point of the ammeter (4) is connected to the ground wire PE interface. The power supplies of the voltmeter (3) and the ammeter (4) are both connected to the live wire L interface and the neutral wire N interface at the lower port of the main air switch (1). The four outlet wires at the lower port of the air switch A (2) are respectively connected to the upper ports of the air switch B (8), the air switch C (9), and the air switch D (10) and the voltage measurement point of the voltmeter (3). The main air switch (1) is connected in series between the live wire L interface and the neutral wire N interface.

2. A device for measuring fault loop ground impedance according to claim 1, characterized in that: Heat dissipation structures (11) are arranged on both sides of the box body (12), the heat dissipation structure (11) comprises porous covers arranged on both sides of the box body (12), a fan for heat dissipation is arranged inside the porous covers, and the power supply component (13) comprises a battery for supplying electric energy to the fan and a switch for controlling the start and stop of the heat dissipation structure (11).

3. A device for measuring fault loop ground impedance according to claim 1, characterized in that: One end of the voltmeter (3) and one end of the ammeter (4) are both connected to the ground wire PE interface via a ground wire.

4. A device for measuring fault loop ground impedance according to claim 1, characterized in that: The live wire L interface, the neutral wire N interface and the ground wire PE interface are vertically distributed on the surface of the box (12) from top to bottom.

5. The device for measuring the ground impedance of a fault loop according to claim 1, characterized in that: The power supply assembly (13), air switch A (2), air switch B (8), air switch C (9), and air switch D (10) are horizontally distributed from left to right on the surface of the box (12).

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