Method for measuring stator bar slot potential of hydro-generator

Abstract

A method for measuring the stator bar slot potential of a hydro-turbine generator includes a potential measurement device comprising a housing, a pressure wheel, a conductive module, and a test rod. The lower end of the housing is connected to the test rod. The pressure wheel includes an insulating roller, a movable rod, and a pressure spring. The insulating roller is connected to one end of the movable rod via a first bearing, and the other end of the movable rod is connected to a second bearing on the housing, on which a pressure spring is mounted. The conductive module includes a copper roller, a conductive copper block, a conductive wire, and a terminal. The copper roller is fixed to the housing via a third bearing; the conductive copper block is fixedly mounted in the cavity of the housing. One end of the conductive wire is connected to the conductive copper block, and the other end of the conductive wire is led out, passed through the test rod, and connected to the terminal. The terminal is fixed to the test rod. The present invention measures the potential difference between the semiconductor non-woven fabric wrapped around the stator bar in the ventilation groove section of the stator core and the stator core, thereby obtaining the stator bar slot potential at that location.

Description

Technical Field

[0001] The present invention belongs to the field of high-voltage testing in the electric power industry, and in particular relates to a method and device for measuring the stator bar slot potential of a hydro-generator. Background Art

[0002] During the installation of large hydroelectric generators, after the stator bars are installed, it is necessary to measure the potential difference between the stator bar surface within the stator core slots and the stator core, known as the slot potential. The slot potential is directly related to the quality of the stator bar installation. Traditional slot potential testing methods measure the potential difference between the stator bar and the core before installing the stator slot wedges. However, there is no effective method for measuring slot potential after slot wedge installation or after the generator set has already been installed. Summary of the Invention

[0003] The purpose of the present invention is to provide a method and device for measuring the stator wire rod slot potential of a hydro-turbine generator, which can be used to measure the stator wire rod slot potential in a generator set after installation. The present invention measures the potential difference between the semiconductor non-woven fabric wrapped around the stator wire rod in the ventilation groove section of the stator core and the stator core, which is the stator wire rod slot potential at that location.

[0004] The technical solution adopted by the present invention is:

[0005] A device for measuring the stator bar slot potential of a hydro-turbine generator comprises a housing, a pressure wheel, a conductive module, and a test rod. The lower end of the housing is connected to the test rod. The pressure wheel comprises an insulating roller, a movable rod, and a pressure spring. The insulating roller is connected to one end of the movable rod via a first bearing, and the other end of the movable rod is connected to a second bearing on the housing. The second bearing is mounted with a pressure spring, which enables the pressure wheel to move at multiple angles within the housing through the deformation of the pressure spring. The conductive module comprises a copper roller, a conductive copper block, a conductive wire, and a terminal. The copper roller is fixed to the housing via a third bearing, allowing it to roll freely. The conductive copper block is fixedly mounted in the housing cavity, and when the copper roller rotates, the conductive copper block and the copper roller remain in contact. One end of the conductive wire is connected to the conductive copper block, and the other end of the conductive wire is led out, passed through the test rod, and connected to the terminal. The terminal is fixed to the test rod and connects the conductive wire to the test circuit.

[0006] The shell is made of insulating material and is in the shape of a flat rectangular parallelepiped. There are two cavities in the shell, which provide a base for the pressure wheel and the conductive module. The pressure wheel and the conductive module are installed inside the shell.

[0007] The conductive module includes dustproof rubbers installed on the housing. The dustproof rubbers are located on both sides of the copper roller and are used to block dirt brought up when the copper roller rotates, thereby protecting the copper roller and the conductive copper block.

[0008] The test rod includes an insulating rod, a scale, and a handle; the insulating rod is connected to the shell, and the insulating rod provides a path for the lead-out of the conductive wire; the scale is used to let the tester know the depth of the test device inserted into the ventilation groove; the handle is used to allow the tester to conveniently hold the test device.

[0009] A method for measuring the slot potential of a stator wire rod in a hydro-turbine generator is disclosed. The method extends a measuring device into a ventilation groove. Under the action of a pressure wheel, a copper roller in a conductive module is pressed tightly against the semiconductor material on the surface of the wire rod in the ventilation groove. The conductive module then conducts the potential value on the semiconductor material on the wire rod surface, thereby obtaining the slot potential value at that location.

[0010] The invention provides a method and device for measuring the slot potential of a stator bar of a hydro-generator, which creates a new method for measuring the slot potential from a ventilation groove and can reliably and conveniently measure the slot potential without destroying the outer slot wedge of the bar. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be further described below with reference to the accompanying drawings and examples:

[0012] Figure 1 Schematic diagram of the structure of the measuring device of the present invention.

[0013] Figure 2 (1) is a top view of the environment inside the stator core ventilation groove.

[0014] Figure 2 (2) is a schematic diagram showing that the measuring device of the present invention is located outside the ventilation trench and the pressure wheel is in a natural state.

[0015] Figure 2 (3) is a schematic diagram of the measuring device of the present invention being located at the air inlet of the ventilation groove, with the copper roller contacting the groove wedge and other insulating materials.

[0016] Figure 2 (4) is a schematic diagram showing that after the measuring device of the present invention enters the ventilation trench, the pressure wheel applies pressure to the ventilation trench support steel bar under the action of the pressure spring.

[0017] Figure 2 (5) is a schematic diagram showing the measuring device of the present invention moved to the farthest point, with the scale on the test rod close to the air inlet of the ventilation ditch.

[0018] Among them: A is the semiconductor material on the surface of the wire rod; B is the ventilation groove supporting steel bar; C is the insulating material such as the slot wedge. DETAILED DESCRIPTION

[0019] A device for measuring the stator bar slot potential of a hydro-turbine generator comprises a housing 1, a pressure wheel 2, a conductive module 3, and a test rod 4. The lower end of the housing 1 is connected to the test rod 4. The pressure wheel 2 comprises an insulating roller 21, a movable rod 22, and a pressure spring 23. The insulating roller 21 is connected to one end of the movable rod 22 via a first bearing. The other end of the movable rod 22 is connected to a second bearing on the housing 1. The second bearing is equipped with a pressure spring 23. The deformation of the pressure spring 23 enables the pressure wheel 2 to move at multiple angles within the housing 1.

[0020] The conductive module 3 includes a copper roller 31, a conductive copper block 32, a conductive wire 33, and a terminal 34. The copper roller 31 is fixed to the housing 1 via a third bearing, allowing it to roll freely. The conductive copper block 32 is fixedly mounted within the cavity of the housing 1, and when the copper roller 31 rotates, the conductive copper block 32 and the copper roller 31 remain in contact. One end of the conductive wire 33 is connected to the conductive copper block 32. The other end of the conductive wire 33 is extended, passes through the test rod 4, and is connected to the terminal 34. The terminal 34 is fixed to the test rod 4 and is used to connect the conductive wire 33 to the test circuit.

[0021] The housing 1 is made of insulating material and is in the shape of a flat rectangular parallelepiped. It contains two cavities, which provide a base for the pressure wheel 2 and the conductive module 3. The pressure wheel 2 forces the copper roller 31 of the device to contact the wire rod slot potential test area, thereby measuring the wire rod slot potential in the ventilation trench. The slot potential can be measured through the ventilation trench without damaging the outer slot wedge of the wire rod.

[0022] The conductive module 3 includes dustproof rubbers 35 , which are mounted on the housing 1 and located on both sides of the copper roller 31 to block dirt brought up by the copper roller 31 during rotation and protect the copper roller 31 and the conductive copper block 32 .

[0023] The test rod 4 includes an insulating rod 41, a scale 42, and a handle 43; the insulating rod 41 is connected to the housing 1, and the insulating rod 41 provides a path for the lead-out of the conductive wire 33; the scale 42 is used to let the tester know the depth of the test device inserted into the ventilation groove; the handle 43 is used to allow the tester to conveniently hold the test device.

[0024] Implementation steps:

[0025] As shown in FIG2 (2), the device of the present invention is located outside the ventilation trench, and the pressure wheel 2 is in a natural state.

[0026] As shown in Figure 2 (3), the device of the present invention is located at the air inlet of the ventilation groove. At this time, the copper roller 31 contacts the insulating material such as the slot wedge, and the pressure wheel 2 contacts the ventilation groove supporting steel bar. Since the size of the air inlet is smaller than that of the present invention, the pressure wheel 2 will be forced to rotate.

[0027] As shown in FIG2 (4), after the device of the present invention enters the ventilation groove, the pressure wheel 2 applies pressure to the ventilation groove supporting steel bar under the action of the pressure spring 23, so that the copper roller 31 is in close contact with the semiconductor material on the surface of the wire rod, part A in FIG2 (1). At this time, the slot potential at this location can be measured.

[0028] As shown in FIG2 (5), the device of the present invention is moved to the farthest point. At this time, the scale 42 on the test rod 4 is close to the air inlet of the ventilation ditch. Further penetration is stopped and the device of the present invention can be slowly moved out. The slot potential test at this point is completed.

Claims

1. A method for measuring the stator bar slot potential of a hydro-generator, characterized by: A potential measuring device is used, comprising a housing (1), a pressure wheel (2), a conductive module (3), and a test rod (4); the device is characterized in that the lower end of the housing (1) is connected to the test rod (4); The pressure wheel (2) comprises an insulating roller (21), a movable rod (22), and a pressure spring (23); the insulating roller (21) is connected to one end of the movable rod (22) via a first bearing, and the other end of the movable rod (22) is connected to a second bearing on the housing (1), and the second bearing is provided with a pressure spring (23). Through the deformation of the pressure spring (23), the pressure wheel (2) can be moved at multiple angles within the housing (1); The conductive module (3) comprises a copper roller (31), a conductive copper block (32), a conductive wire (33), and a connection terminal (34); The copper roller (31) is fixed to the housing (1) via a third bearing, and the copper roller (31) can roll freely; the conductive copper block (32) is fixedly installed in the cavity of the housing (1), and when the copper roller (31) rotates, the conductive copper block (32) and the copper roller (31) are always in a fitted state; One end of the conductive wire (33) is connected to the conductive copper block (32), and the other end of the conductive wire (33) is led out and passed through the test rod (4) to be connected to the wiring terminal (34); The wiring terminal (34) is fixed on the test rod (4) and is used to connect the conductive wire (33) and the test circuit; By extending the potential measuring device into the ventilation groove, under the action of the pressure wheel (2), the copper roller (31) in the conductive module (3) is tightly attached to the semiconductor material on the surface of the wire rod in the ventilation groove, and the conductive module (3) conducts the potential value on the semiconductor material on the surface of the wire rod, thereby obtaining the slot potential value at that location.

2. The method for measuring the stator bar slot potential of a hydro-generator according to claim 1, characterized in that: The shell (1) is made of insulating material and is in the shape of a flat rectangular parallelepiped. The shell (1) has two cavities, which provide a base for the pressure wheel (2) and the conductive module (3). The pressure wheel (2) and the conductive module (3) are installed inside the shell (1).

3. The method for measuring the stator bar slot potential of a hydro-generator according to claim 1, characterized in that: The conductive module (3) includes a dustproof rubber (35) mounted on the housing (1). The dustproof rubber (35) is located on both sides of the copper roller (31) and is used to block dirt brought up when the copper roller (31) rotates, thereby protecting the copper roller (31) and the conductive copper block (32).

4. The method for measuring the stator bar slot potential of a hydro-generator according to claim 1, characterized in that: The test rod (4) comprises an insulating rod (41), a scale (42), and a handle (43); the insulating rod (41) is connected to the housing (1), and the insulating rod (41) provides a path for the conductive wire (33) to be led out; the scale (42) is used to let the tester know the depth of the test device inserted into the ventilation groove; and the handle (43) is used to allow the tester to conveniently hold the test device.

5. A method for measuring the stator bar slot potential of a hydro-generator, characterized by: A potential measuring device is used, comprising a housing (1), a pressure wheel (2), a conductive module (3), and a test rod (4); the device is characterized in that the lower end of the housing (1) is connected to the test rod (4); The pressure wheel (2) comprises an insulating roller (21), a movable rod (22), and a pressure spring (23); the insulating roller (21) is connected to one end of the movable rod (22) via a first bearing, and the other end of the movable rod (22) is connected to a second bearing on the housing (1), and the second bearing is provided with a pressure spring (23). Through the deformation of the pressure spring (23), the pressure wheel (2) can be moved at multiple angles within the housing (1); The conductive module (3) comprises a copper roller (31), a conductive copper block (32), a conductive wire (33), and a connection terminal (34); The copper roller (31) is fixed to the housing (1) via a third bearing, and the copper roller (31) can roll freely; the conductive copper block (32) is fixedly installed in the cavity of the housing (1), and when the copper roller (31) rotates, the conductive copper block (32) and the copper roller (31) are always in a fitted state; One end of the conductive wire (33) is connected to the conductive copper block (32), and the other end of the conductive wire (33) is led out and passed through the test rod (4) to be connected to the wiring terminal (34); The wiring terminal (34) is fixed on the test rod (4) and is used to connect the conductive wire (33) and the test circuit; The potential measurement method includes the following steps: Step 1: The measuring device is located outside the ventilation trench, and the pressure wheel (2) is in a natural state; Step 2: The measuring device is located at the air inlet of the ventilation groove. At this time, the copper roller (31) contacts the slot wedge insulation material, and the pressure wheel (2) contacts the ventilation groove support steel bar. Since the size of the air inlet is smaller than the size of the measuring device, the pressure wheel (2) is pressed to rotate; Step 3: After the measuring device enters the ventilation groove, the pressure wheel (2) applies pressure to the ventilation groove supporting steel bar under the action of the pressure spring (23), so that the copper roller (31) is in close contact with the semiconductor material on the surface of the wire rod. At this time, the slot potential at that location can be measured; Step 4: The measuring device is moved to the farthest point. At this time, the scale (42) on the test rod (4) is close to the air inlet of the ventilation groove. Stop going deeper and slowly move the measuring device out. The potential test of the groove at this point is completed.

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