A grounding device with the function of detecting contact resistance

Abstract

The grounding device with the function of detecting contact resistance in the present invention belongs to the field of maintenance of power system equipment. Specifically, it is a grounding device that ensures reliable grounding during the maintenance of power system equipment, and is particularly suitable for the protective grounding during the maintenance of high-voltage equipment. A grounding device with the function of detecting contact resistance includes a wire clamp and a measurement circuit. The wire clamp includes a main body frame, a top pressure rod, a top pressure block, and a drainage wire. The measurement circuit includes a test button, a measurement circuit wire, a contact piece, and a detection device. The drainage wire and the measurement circuit wire are parallel inside a transparent insulating sheath. Among them, the main body frame is a door-shaped or U-shaped conductive frame with an opening. The drainage wire is connected to the main body frame, and the other end of the drainage wire is electrically connected to a measurement device. The top pressure rod is a threaded rod, and a corresponding internal threaded through hole is provided below the main body frame. The top end of the top pressure rod is movably connected to the top pressure block, and the top pressure block is located inside the main body frame. An insulating rod is connected below the top pressure rod.

Description

Technical Field

[0001] The grounding device with the function of detecting contact resistance of the present invention belongs to the field of maintenance of power system equipment. Specifically, it is a grounding device for ensuring reliable grounding during the maintenance of power system equipment, and is particularly suitable for the protective grounding during the maintenance of high-voltage equipment. Background Art

[0002] Grounding the maintenance equipment is the most direct and reliable method to ensure the safety of maintenance personnel. People must also work within the protection range of the grounding wire during the maintenance process to be safe. However, if the grounding wire is not properly hung, such as poor contact, etc., the residual charge of the maintenance equipment cannot be fully discharged or external induced electricity may enter the maintenance equipment. Especially for equipment with cross-over and same-pole erection, the induced electricity can reach several hundred volts or even more than a thousand volts, which poses a great potential safety hazard to the maintenance personnel.

[0003] At present, there are mainly the following two situations that cause the maintenance equipment to be unable to be effectively grounded (the grounding wire is not properly installed):

[0004] 1. Insufficient positive pressure;

[0005] The positive pressure of the contact is the force generated on the mutually contacting surfaces and perpendicular to the contact surface. As the positive pressure increases, the number and area of the contact micro-points also gradually increase, and at the same time, the contact micro-points transition from elastic deformation to plastic deformation; that is to say, when the positive pressure is insufficient, the contact surface becomes smaller and the contact resistance increases; when we hang the grounding wire, due to the oxidation and rust of the rotating screw of the operating rod, it is difficult to turn, or due to incorrect operation, the grounding wire port is not tightly clamped or is falsely clamped.

[0006] 2. Large surface conduction resistance;

[0007] An oxide layer (once the metal is exposed to the atmosphere, an initial oxide film layer of several micrometers will be quickly formed), oil stains or other pollutants will be formed on the surface of any conductor after installation and use, and a film resistance will be generated on the surfaces of the two contacts; since the film layer is a poor conductor, as the film layer thickness increases, the contact area shrinks and the contact resistance increases.

[0008] Both of the above situations may lead to unqualified installation of the grounding wire for the protection of the maintenance equipment, an increase in the grounding resistance of the equipment, an increase in the residual voltage of the induced electricity of the maintenance equipment, and a threat to the safety of the maintenance personnel. Therefore, it is necessary to provide a new device to meet the actual maintenance needs. Summary of the Invention

[0009] The purpose of the present invention is to provide a grounding device with the function of detecting contact resistance in view of the above deficiencies, which is applied to the maintenance of power system transmission, transformation, and distribution substation equipment, prevents the grounding resistance from being too large due to unqualified installation quality of the protective grounding wire, and the induced electricity from injuring people, and ensures a reliable grounding wire for the maintenance equipment.

[0010] The present invention is implemented by adopting the following technical solutions:

[0011] A grounding device with a function of detecting contact resistance has a wire clamp, and the wire clamp includes a main body frame, a drainage wire, a measurement return wire, a top pressure rod and a top pressure block; the drainage wire and the measurement return wire are connected in parallel;

[0012] Wherein the main body frame is a portal-shaped or U-shaped conductive frame with an opening, the drainage wire is connected to the main body frame, and the other end of the drainage wire is connected with a measuring device; the top pressure rod is a threaded rod, and a corresponding internal thread through hole is arranged below the main body frame. The top end of the top pressure rod is movably connected with a top pressure block, the top pressure block is located inside the main body frame, and an insulating rod is connected below the top pressure rod. By rotating the insulating rod, the lifting of the top pressure block can be controlled.

[0013] A dovetail groove is arranged on the upper surface of the top pressure block, and a measurement contact body can be connected by means of a dovetail groove and a tenon.

[0014] The measurement contact body respectively has a mounting and fixing block, an insulating layer and a contact piece from bottom to top; wherein the bottom of the mounting and fixing block has a tenon matching with the dovetail groove, a wiring hole is arranged on the side surface of the contact piece, the wiring hole is connected with a measurement return wire, and the other end of the measurement return wire is connected to the measuring device.

[0015] Further, the drainage wire and the measurement return wire are connected in parallel and wrapped together by an outer sheath. The measurement return wire has an insulating layer, so that the routing of the cable is gathered and kept insulated to a certain extent. The measurement return wire is one or three. When it is one, single-phase electricity is measured. When it is three, each phase of the three-phase electricity is measured.

[0016] The drainage wire is one or three. When it is one, it is used for single-phase electricity grounding. When it is three, it is used for three-phase grounding and short-circuiting, and is divided into a head end and a tail end (trident shape). The three at the head end are respectively used for phases A, B, and C, and the tail end is one connected to a grounding rod.

[0017] Further, the outer sheath is a transparent outer sheath.

[0018] A mouth-shaped frame is welded or riveted on the back of the top pressure block, and through holes are arranged on the mouth-shaped frame. The top of the top pressure rod has a screw head, and the screw head is located inside the mouth-shaped frame, so that the top pressure rod can push the top pressure block to move up and down without rotation.

[0019] A dorsal fin is arranged at the rear side of the main body frame, and a connection hole is arranged on the dorsal fin. The drainage wire is electrically connected to the main body frame through the connection hole, and the connection hole is a threaded hole.

[0020] The described measuring device has a cuboid-shaped housing. An equipment compartment is provided inside the housing. A battery and a detection device are respectively installed in the equipment compartment from bottom to top. Cover plates are respectively arranged above and below the equipment compartment. The cover plates are fixedly connected to the housing by screws (the lower cover plate is an iron plate of the same size as the frame). A transparent observation window is provided on the upper cover plate. The observation window is located above the detection device. On the cover plate, 2 or 4 test buttons are arranged on one side of the observation window. When there are 2 test buttons, single-phase electricity is tested. When there are 4 test buttons, three-phase electricity is tested. One of the 2 or 4 test buttons is a power switch button, and the rest are test buttons. Each test button is respectively connected to the measurement circuit line of the corresponding phase. Both ends of the housing respectively have connection wire noses. One end is connected to the drain wire, and the other end is connected to a grounding rod. The grounding rod is connected to the grounding grid (or connected to the earth), which serves to introduce the remaining charge of the maintenance equipment into the earth and prevent misfeeding voltage or induction from entering the maintenance equipment.

[0021] The described detection device is an ohmmeter with a liquid crystal display screen. The detection device is electrically connected to the housing. The ohmmeter is a commercially available ratio measurement method ohmmeter.

[0022] The battery is a lithium battery or a silver-zinc battery.

[0023] The drain wire is the main path for discharging current and pressure. It is connected by soft copper wires with a cross-sectional area of 25mm 2 or 35mm 2 and is sheathed with a transparent insulating sheath. The three at the first end are respectively connected to three (A, B, C) wire clips, and the other end is connected together to form a contact point as a three-phase short circuit wire. Then it is led out from the short contact point to the grounding rod for grounding.

[0024] The cross-sectional area of the measurement circuit line is smaller than that of the drain wire, preferably 0.3mm 2 -1mm 2 and further preferably 0.5mm 2 .

[0025] When the present invention is in use, a conductor (copper-aluminum busbar or copper-aluminum wire connected to the maintenance equipment) is placed into the main body frame. The insulating rod at the lower half of the pressing rod is rotated by hand to tightly press the conductor in the main body frame. The power switch button on the measuring device is pressed, and then any one of the remaining test buttons is pressed to detect the contact resistance of the installed grounding wire.

[0026] When it is necessary to measure the contact resistance, after turning on the power switch, press one of the buttons. At this time, the voltage forms a closed measurement circuit through the test button - measurement return line - contact body - conductor (copper bar) - wire clamp - grounding wire - measuring ohmmeter. At this time, the DC resistance value of the circuit will appear on the display of the ohmmeter; when the contact resistance exceeds the set value, an alarm will sound to remind the operator to reinstall until it is qualified. In this way, it can ensure that the overhaul equipment is grounded feasibly, avoiding the danger of high residual voltage of induced electricity caused by false clamping of the grounding wire and hurting people.

[0027] Advantages of the invention: By studying the deficiencies existing in the use of the existing grounding wire, the present invention proposes a new physical structure method. A contact point insulated from the wiring itself is provided on the lower clamping top block of the wire clamp. Using the drain wire (current conduction) itself as part of the measurement grounding resistance return line, a measurement device is added to the grounding pile. After the grounding wire is installed, the contact resistance between the grounding wire clamp and the conductor can be measured through the test button on the measurement device. In this way, it can prevent incomplete grounding or false grounding phenomena where the grounding resistance increases due to aging and rotation of the grounding wire clamp, inaccurate force judgment (sometimes it may be misjudged as being clamped because it cannot be rotated), and the formation of a semi-insulating layer due to oxidation and dust accumulation on the conductor. It effectively solves the problem that it is impossible to judge whether the grounding wire is qualified after installation in the past. Thus, it avoids the danger to the personal safety of maintenance personnel due to high residual voltage on the overhaul equipment caused by excessive contact resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below in conjunction with the accompanying drawings;

[0029] Figure 1 is a three-dimensional structure schematic diagram of the present invention (the measurement contact body is inserted above the top pressure block through the dovetail groove);

[0030] Figure 2 is a three-dimensional structure schematic diagram of the present invention (the measurement contact body is not inserted above the top pressure block through the dovetail groove);

[0031] Figure 3 is a structure schematic diagram of the main body frame of the present invention;

[0032] Figure 4 is a structure schematic diagram of the top pressure block of the present invention;

[0033] Figure 5 is a structure schematic diagram of the measurement device of the present invention;

[0034] Figure 6 is a structure schematic diagram of the cover plate of the measurement device of the present invention;

[0035] Figure 7 is a structure schematic diagram between the top pressure rod and the top pressure block of the present invention;

[0036] Figure 8 It is the schematic diagram of the measurement circuit of the present invention;

[0037] Figure 9 It is the schematic structural diagram when the drainage wire and the measurement circuit wire of the present invention are hinged together (the measurement circuit wire is three). Specific embodiments

[0038] Refer to the appendix Figures 1-9 , a grounding device with a function of detecting contact resistance has a wire clamp and a measuring device. The wire clamp includes a main body frame 1, a drainage wire 2, a measurement circuit wire 9, a pressing rod 3 and a pressing block 4; the drainage wire 2 and the measurement circuit wire 9 are connected in parallel to the measuring device 5 (the drainage wire 2 is connected to the housing of the measuring device, and the measurement circuit wire 9 is connected to the ohmmeter of the measuring device);

[0039] Among them, the main body frame 1 is a portal-shaped or U-shaped conductive frame with an opening. The drainage wire 2 is connected to the main body frame 1, and the other end of the drainage wire 2 is electrically connected to a measuring device 5; the pressing rod 3 is a threaded rod, and a corresponding internal threaded through hole is provided below the main body frame 1. The top end of the pressing rod 3 is movably connected to a pressing block 4. The pressing block 4 is located inside the main body frame 1. An insulating rod 3-2 is connected below the pressing rod 3, and the lifting of the pressing block 4 can be controlled by rotating the insulating rod 3-2.

[0040] A dovetail groove 4-1 is provided on the upper surface of the pressing block 4, and a measurement contact body 6 can be connected by mortise connection through the dovetail groove 4-1,

[0041] The measurement contact body 6 respectively has a mounting and fixing block 6-1, an insulating layer 6-2 and a contact piece 6-3 from bottom to top; among them, the bottom of the mounting and fixing block 6-1 has a mortise matching the dovetail groove 4-1. A wiring hole 6-3-1 is provided on the side of the contact piece 6-3. The wiring hole 6-3-1 is connected to a measurement circuit wire 9, and the other end of the measurement circuit wire 9 is connected to a detection device (ohmmeter) 5-4 in the measuring device 5.

[0042] Furthermore, the drainage wire 2 and the measurement circuit wire 9 are connected in parallel. The drainage wire 2 and the measurement circuit wire 9 are insulated from each other and wrapped together by an outer sheath 10, so that the routing of the cables is gathered.

[0043] Furthermore, the drainage wire 2 and the measurement circuit wire 9 are arranged in parallel. The drainage wire 2 and the measurement circuit wire 9 are wrapped together by an outer sheath. The measurement circuit wire 9 has an insulating layer, so that the routing of the cables is gathered and kept insulated to a certain extent. The number of the measurement circuit wires 9 is one or three. When there is one, single-phase electricity is measured. When there are three, each phase of the three-phase electricity is measured.

[0044] The three drainage wires 2 are combined into one. The drainage wire 2 is divided into a head end and a tail end. The head end is three, and the tail end is one. They are electrically connected between the head end and the tail end.

[0045] Furthermore, the outer sheath is a transparent outer sheath.

[0046] A mouth-shaped frame 4-2 is welded or riveted to the back of the pressing block 4. Through holes are provided on the mouth-shaped frame 4-2. The top of the pressing rod 3 has a screw head 3-1, and the screw head 3-1 is located within the mouth-shaped frame 4-2, so that the pressing rod 3 can push the pressing block 4 to move up and down without rotation.

[0047] A dorsal fin 1-1 is provided at the rear side of the main body frame 1. Connecting holes are provided on the dorsal fin 1-1. The drainage wire 2 is connected to the main body frame 1 through the connecting holes, and the connecting holes are threaded holes.

[0048] The measuring device 5 has a cuboid housing 5-1. An equipment chamber 5-2 is provided within the housing 5-1. A battery 5-3 and a detection device 5-4 are respectively installed in the equipment chamber 5-2 from bottom to top. A cover plate 5-5 is provided above the equipment chamber 5-2. The cover plate 5-5 is fixedly connected to the housing 5-1 by screws. A transparent observation window 5-5-1 is provided on the cover plate 5-5. The observation window 5-5-1 is located above the detection device 5-4. Two or four test buttons are provided on one side of the observation window 5-5-1 on the cover plate 5-5. When there are two test buttons, single-phase electricity is tested; when there are four test buttons, three-phase electricity is tested. One of the two or four test buttons is a power switch button 5-4-1, and the rest are test buttons. Each test button is respectively connected to the measurement circuit line of the corresponding phase 5-4-2. Connection lugs 5-6 are respectively provided at both ends of the housing 5-1. The connection lug 5-6 on one side of the housing 5-1 is connected to the drainage wire 2 through an adapter 8, and the adapter 8 is connected to the detection device 5-4. The connection lug 5-6 on the other side of the housing 5-1 is electrically connected to a grounding rod 7, and the grounding rod 7 is grounded to play a role in grounding and draining the current.

[0049] The detection device 5-4 is an ohmmeter with a liquid crystal display screen. The detection device 5-4 is electrically connected to the housing 5-1, and the ohmmeter is a commercially available ratio measurement method ohmmeter.

[0050] The battery 5-3 is a lithium battery or a silver-zinc battery.

[0051] The drainage wire 2 is the main path for discharging current and pressure. It is formed by connecting soft copper wires with a cross-sectional area of 25 mm 2 or 35 mm 2 and is sheathed with a transparent insulating sheath. The three at the first end are respectively connected to three (A, B, C) wire clips, and the other ends are connected together to form a joint as a three-phase short circuit wire. Then, a wire is led out from the short circuit joint and connected to the housing of the measuring device 5 and then connected to the ground through a ground rod for grounding.

[0052] The cross-section of the measurement loop wire 9 is smaller than that of the drainage wire 2, preferably 0.3 mm 2 -1.0 mm 2 Soft copper core insulated wire, more preferably 0.5 mm 2 。

[0053] When the present invention is in use, the opening of the U-shaped main body frame 1 is clamped on the conductor, and the insulating rod 3-2 of the lower half of the pressing rod 3 is rotated by hand. After the wire clamp is tightened, the power switch button 5-4-1 on the measuring device is pressed, and any one of the remaining test buttons is pressed to perform a power-on detection between the wire clamp and the conductor.

[0054] When the contact resistance needs to be measured, after the power switch is turned on, press one of the buttons. At this time, the voltage passes through the wire clamp main body frame 1--conductor——contact piece 6-3 on the measurement contact body 6——measurement loop wire 9——detection device 5-4——grounding drainage wire 2 to form a closed circuit measurement loop. At this time, the DC resistance value of the loop will appear on the display of the ohmmeter; when the contact resistance exceeds the set value, an alarm will be issued to remind the operator to reinstall until it is qualified. In this way, it can ensure that the maintenance equipment is grounded feasibly and avoid the danger of high residual voltage of induced electricity caused by false clamping of the grounding wire and hurting people.

Claims

1. A grounding device with the function of detecting contact resistance, characterized in that: It has a wire clamp and a measurement circuit. The wire clamp includes a main body frame, a top pressure rod, a top pressure block, and a drainage wire. The measurement circuit includes a test button, a measurement circuit wire, a contact piece, and a detection device; the drainage wire and the measurement circuit wire are parallel. Among them, the main body frame is a gate-shaped or U-shaped conductive frame with an opening. The drainage wire is connected to the main body frame, and the other end of the drainage wire is connected with a measurement device; the top pressure rod is a threaded rod, and corresponding internal threaded through holes are provided below the main body frame. The top of the top pressure rod is movably connected with a top pressure block, and the top pressure block is located inside the main body frame. An insulating rod is connected below the top pressure rod, and the lifting of the top pressure block can be controlled by rotating the insulating rod. A dovetail groove is provided on the upper surface of the top pressure block, and a measurement contact body can be connected by tenon through the dovetail groove. The measurement contact body has an installation and fixing block, an insulating layer, and a contact piece from bottom to top; among them, the bottom of the installation and fixing block has a tenon matching the dovetail groove, a wiring hole is provided on the side of the contact piece, the wiring hole is connected with a measurement circuit wire, and the other end of the measurement circuit wire is connected to the measurement device. The drainage wire and the measurement circuit wire are parallel together, and the drainage wire and the measurement circuit wire are wrapped together by a transparent outer sheath. The measurement circuit wire has an insulating layer, and the measurement circuit wire is one or three. When it is one, single-phase electricity is measured, and when it is three, each phase of three-phase electricity is measured. The drainage wire is combined from three into one, and the drainage wire is divided into a head end and a tail end. The head end is three, and the tail end is one. The head end and the tail end are electrically connected. The measurement device has a cuboid shell. An equipment compartment is opened in the shell. A battery and a detection device are installed in the equipment compartment from bottom to top. A cover plate is provided above the equipment compartment. The cover plate is fixedly connected to the shell by screws. A transparent observation window is provided on the cover plate. The observation window is located above the detection device. There are 2 or 4 test buttons provided on one side of the observation window on the cover plate. Among them, when there are 2 test buttons, single-phase electricity is tested, and when there are 4 test buttons, three-phase electricity is tested; one of the 2 or 4 test buttons is a power switch button, and the rest are test buttons. Each test button is respectively connected to the measurement circuit wire of the corresponding phase; connection nose pieces are respectively provided at both ends of the shell. The connection nose piece on one side of the shell is connected to a drainage wire through a transfer piece, and the transfer piece is connected to the detection device; the connection nose piece on the other side of the shell is electrically connected to a grounding rod, and the grounding rod is grounded to play a role in discharging voltage to ensure that the overhaul equipment is not energized.

2. The grounding device with the function of detecting contact resistance according to claim 1, wherein: A mouth-shaped frame is welded or riveted on the back of the top pressure block. Through holes are provided on the mouth-shaped frame. The top of the top pressure rod has a screw head, and the screw head is located inside the mouth-shaped frame, so that the top pressure rod can push the top pressure block to move up and down without rotation.

3. The grounding device with the function of detecting contact resistance according to claim 1, characterized in that: A dorsal fin is provided at the rear side of the main body frame. There are connection holes on the dorsal fin. The drainage wire is electrically connected to the main body frame through the connection holes. The connection holes are threaded holes.

4. The grounding device with the function of detecting contact resistance according to claim 1, characterized in that: The detection device is an ohmmeter with a liquid crystal display screen. The detection device is electrically connected to the shell. The ohmmeter is a commercially available ratio measurement method ohmmeter.

5. The grounding device with the function of detecting contact resistance according to claim 1, characterized in that: The battery is a lithium battery or a silver-zinc battery.

6. The grounding device with the function of detecting contact resistance according to claim 1, characterized in that: The drain wire is made of soft copper wire with a cross-section of 25mm 2 or 35mm 2 and is sleeved with a transparent insulating sheath on the outside. The three at the head end of the drain wire are respectively connected to three wire clamps. The tail end serves as a three-phase short circuit wire, is connected to the housing of the measuring device, and then is connected to the ground through a ground rod for grounding purposes.

7. The grounding device with the function of detecting contact resistance according to claim 6, characterized in that: The cross-section of the measurement circuit wire is smaller than that of the soft copper core insulated wire of the drainage wire.

8. The working method of a grounding device with a function of detecting contact resistance according to claim 1, characterized in that: During use, the opening of the U-shaped main body frame is clamped on the conductor, and the insulating rod at the lower half of the pressing rod is rotated by hand. After the wire clamp is tightened, the power switch button on the measuring device is pressed, and any one of the remaining test buttons is pressed to conduct a power-on test between the wire clamp and the conductor; When measuring the contact resistance, after turning on the power switch, press one of the buttons. At this time, the voltage passes through the wire clamp main body frame - conductor - contact piece on the measuring contact body - measuring return wire - detection device - grounding drainage wire - grounding rod to form a closed circuit measurement loop. At this time, the display of the ohmmeter will show the DC resistance value of the loop; when the contact resistance exceeds the set value, an alarm will be issued to remind the operator to reinstall until it is qualified.

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