Generator shaft voltage measurement conversion device and method

Abstract

The invention discloses a generator shaft voltage measurement conversion device and method. According to the device, a change-over switch, a steam end binding post, a large shaft grounding binding post, an excitation end binding post, a direct current voltmeter and an alternating current voltmeter are arranged on an insulating plate; the steam end binding post and the excitation end binding post are both used for being connected with a generator rotor. The excitation end binding post, the large shaft grounding binding post and the steam end binding post are all connected with an input contact of the change-over switch; the DC voltmeter and the DC fling-cut switch are connected in series to form a DC voltage measuring circuit, and the AC voltmeter and the AC fling-cut switch are connected in series to form an AC voltage measuring circuit; the direct-current voltage measuring circuit and the alternating-current voltage measuring circuit are connected in parallel and then are connected with an output contact of the change-over switch; by operating the direct-current fling-cut switch, the alternating-current fling-cut switch and the change-over switch, the measurement of the alternating-current shaft voltage and the direct-current shaft voltage of each shaft position of the generator can be realized. Operation is simple and convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of generator shaft voltage measurement, and particularly to a generator shaft voltage measurement conversion device and method. Background Art

[0002] The statements in this part merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] During the installation and operation of a generator, due to reasons such as the asymmetry of the generator magnetic flux and the poor shaft seal of the steam turbine coaxial with the generator, a voltage may be generated on the generator shaft. When the shaft voltage is sufficient to break down the oil film between the shaft and the bearing, a discharge phenomenon will occur. The shaft current will gradually deteriorate the quality of the oil used for lubrication and cooling. In severe cases, the bearing bush will be burned out, and forced shutdown will cause accidents. Therefore, it is very necessary to check and measure the shaft voltage of the generator.

[0004] The shaft voltage of the generator includes the DC shaft voltage and the AC shaft voltage of the generator; currently, a multimeter is used to measure the shaft voltage of the generator. During the measurement, the wiring needs to be reconnected for each measurement point of the shaft voltage. The test execution process is relatively cumbersome, the test execution time is long, and at the same time, multiple wiring changes during the measurement process increase the hidden danger of measurement wiring errors. Summary of the Invention

[0005] In order to solve the above problems, the present invention proposes a generator shaft voltage measurement conversion device and method. By simply operating the conversion switch and the switching switch, the measurement of various shaft voltages of the generator can be realized, and the measurement is simple and convenient.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, a generator shaft voltage measurement conversion device is proposed, which includes an insulating board; a conversion switch, a steam end terminal, a large shaft grounding terminal, an excitation end terminal, a DC voltmeter, and an AC voltmeter are arranged on the insulating board; both the steam end terminal and the excitation end terminal are used to connect to the generator rotor;

[0008] The excitation end terminal, the large shaft grounding terminal, and the steam end terminal are all connected to the input contacts of the conversion switch; the DC voltmeter is connected in series with the DC switching switch to form a DC voltage measurement circuit, and the AC voltmeter is connected in series with the AC switching switch to form an AC voltage measurement circuit; the DC voltage measurement circuit and the AC voltage measurement circuit are connected in parallel and then connected to the output contacts of the conversion switch;

[0009] When the DC switching switch is closed and the AC switching switch is open, the DC shaft voltage of the generator can be measured through the DC voltmeter; when the DC switching switch is open and the AC switching switch is closed, the AC shaft voltage of the generator can be measured through the AC voltmeter.

[0010] Further, an equipment grounding terminal is also provided on the insulating board, and the equipment grounding terminal is used to connect to the ground.

[0011] Further, the change-over switch includes four positions, namely the opening position, the measuring position of the shaft voltage between the steam end and the ground, the measuring position of the shaft voltage between the excitation end and the ground, and the measuring position of the shaft voltage between the steam end and the excitation end; when the change-over switch is in the opening position, there is no conduction between the input contacts and the output contacts of the change-over switch; when the change-over switch is in the measuring position of the shaft voltage between the steam end and the ground, the shaft voltage between the steam end of the generator and the ground can be measured by an AC voltmeter or a DC voltmeter; when the change-over switch is in the measuring position of the shaft voltage between the excitation end and the ground, the shaft voltage between the excitation end of the generator and the ground can be measured by an AC voltmeter or a DC voltmeter; when the change-over switch is in the measuring position of the shaft voltage between the steam end and the excitation end, the shaft voltage between the steam end and the excitation end of the generator can be measured by an AC voltmeter or a DC voltmeter.

[0012] Further, the change-over switch includes eight contacts, namely input contact 1, input contact 2, input contact 3, input contact 4, output contact 5, input contact 6, output contact 7, and input contact 8; input contact 1 and input contact 3 are conductively connected; input contact 2 and input contact 6 are conductively connected; input contact 4 and input contact 8 are conductively connected; when the change-over switch is in the opening position, there is no conduction in the circuits between input contact 1 and input contact 2, input contact 3 and input contact 4, output contact 5 and input contact 6, and output contact 7 and input contact 8; when the change-over switch is in the measuring position of the shaft voltage between the steam end and the ground, the circuits between input contact 3 and input contact 4 and between output contact 5 and input contact 6 are both conductive, and the circuits between input contact 1 and input contact 2 and between output contact 7 and input contact 8 are not conductive; when the change-over switch is in the measuring position of the shaft voltage between the excitation end and the ground, the circuits between input contact 1 and input contact 2 and between input contact 3 and input contact 4 are not conductive, and the circuits between output contact 5 and input contact 6 and between output contact 7 and input contact 8 are both conductive; when the change-over switch is in the measuring position of the shaft voltage between the steam end and the excitation end, the circuits between input contact 1 and input contact 2 and between output contact 7 and input contact 8 are both conductive, and the circuits between input contact 3 and input contact 4 and between output contact 5 and input contact 6 are not conductive.

[0013] Further, a box body is also included, and the insulating board, the change-over switch, the steam end terminal, the large shaft grounding terminal, the excitation end terminal, the DC voltmeter, and the AC voltmeter are all located inside the box body.

[0014] Further, the large shaft grounding terminal is used to connect to the large shaft grounding end of the generator rotor.

[0015] Further, the steam end terminal is connected to the steam end connection port; the exciter end terminal is connected to the exciter end connection port; both the steam end connection port and the exciter end connection port are used to connect to the generator rotor.

[0016] In a second aspect, a method for measuring the shaft voltage of a generator is proposed, including:

[0017] Connect the steam end terminal and the exciter end terminal to the generator rotor;

[0018] Close the DC switching switch, open the AC switching switch, and measure the DC shaft voltage of the generator through a DC voltmeter;

[0019] Open the DC switching switch, close the AC switching switch, and measure the AC shaft voltage of the generator through an AC voltmeter.

[0020] Further, when measuring the DC shaft voltage of the generator through a DC voltmeter or measuring the AC shaft voltage of the generator through an AC voltmeter, by switching the gear of the transfer switch, measure the shaft voltage of the steam end to ground, the shaft voltage of the exciter end to ground, and the shaft voltage of the steam end to the exciter end of the generator.

[0021] Further, in the state where the transfer switch is in the off position, connect the steam end terminal and the exciter end terminal to the generator rotor.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] The present invention proposes a generator shaft voltage measurement conversion device and method. The conversion device connects the exciter end terminal, the large shaft grounding terminal, and the steam end terminal to the input contacts of the transfer switch; the DC voltmeter and the DC switching switch are connected in series to form a DC voltage measurement circuit, and the AC voltmeter and the AC switching switch are connected in series to form an AC voltage measurement circuit; the DC voltage measurement circuit and the AC voltage measurement circuit are connected in parallel and then connected to the output contacts of the transfer switch; when the DC switching switch is closed and the AC switching switch is open, the DC shaft voltage of the generator can be measured through the DC voltmeter; when the DC switching switch is open and the AC switching switch is closed, the AC shaft voltage of the generator can be measured through the AC voltmeter; therefore, when using the conversion device to measure the shaft voltage of the generator, only need to connect the steam end terminal and the exciter end terminal to the generator rotor before measuring the shaft voltage, and then, by operating the transfer switch and the switching switch, the measurement of various shaft voltages of the generator can be realized, and the operation is simple and fast; the wiring layout work in the intermediate link is omitted, which not only simplifies the measurement process from complex to simple, but also effectively improves the work efficiency.

[0024] The advantages of the additional aspects of the present invention will be partially given in the following description, partially will become obvious from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The attached drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application.

[0026] Figure 1 Schematic layout diagram of a large motor shaft voltage measuring device disclosed for the embodiment;

[0027] Figure 2 Schematic circuit connection diagram in a large motor shaft voltage measuring device disclosed for the embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The present invention will be further described below in conjunction with the drawings and embodiments.

[0029] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanations for this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to this application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] In the present invention, terms such as "fixed connection", "connected", "connected" should be understood in a broad sense, which may mean a fixed connection, an integral connection or a detachable connection; it may be directly connected or indirectly connected through an intermediate medium. For those relevant scientific research or technical personnel in the field, the specific meanings of the above terms in the present invention can be determined according to specific situations and should not be construed as a limitation to the present invention.

[0032] Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0033] Embodiment 1

[0034] In this embodiment, a generator shaft voltage measuring and converting device is disclosed, as Figure 1 , Figure 2 shown, which includes an insulating board; a change-over switch, a steam end terminal, a large shaft grounding terminal, an excitation end terminal, a DC voltmeter and an AC voltmeter are arranged on the insulating board; both the steam end terminal and the excitation end terminal are used to connect with the generator rotor;

[0035] The exciting end terminal, the large shaft grounding terminal and the steam end terminal are all connected to the input contacts of the change-over switch; the DC voltmeter is connected in series with the DC switching switch to form a DC voltage measurement circuit, and the AC voltmeter is connected in series with the AC switching switch to form an AC voltage measurement circuit; the DC voltage measurement circuit and the AC voltage measurement circuit are connected in parallel and then connected to the output contacts of the change-over switch.

[0036] When the DC switching switch is closed and the AC switching switch is open, the DC shaft voltage of the generator can be measured through the DC voltmeter; when the DC switching switch is open and the AC switching switch is closed, the AC shaft voltage of the generator can be measured through the AC voltmeter.

[0037] In this embodiment, an equipment grounding terminal is further arranged on the insulating board as the protective grounding of the device, and the equipment grounding terminal is used to connect to the ground.

[0038] The large shaft grounding terminal of this embodiment is used to connect to the large shaft grounding end of the generator rotor.

[0039] The steam end terminal of this embodiment is connected to the steam end wiring port; the exciting end terminal is connected to the exciting end wiring port; both the steam end wiring port and the exciting end wiring port are used to connect to the generator rotor.

[0040] Preferably, the AC voltmeter adopts a high internal resistance AC voltmeter; both the AC switching switch and the DC switching switch adopt 2P voltage switches.

[0041] The AC voltmeter, the AC switching switch, the change-over switch, the DC switching switch and the DC voltmeter are arranged in sequence from left to right at the lower end of the insulating board. The change-over switch, the steam end terminal, the large shaft grounding terminal, the exciting end terminal, the equipment grounding terminal, the DC switching switch, the AC switching switch, the DC voltmeter and the AC voltmeter are all arranged on the upper surface of the insulating board; electrical wiring is arranged on the back of the insulating board to realize the connection between various electrical components.

[0042] Among them, the DC switching switch is used for the switching of the DC voltmeter, and the AC switching switch is used for the switching of the AC voltmeter; the change-over switch is used to switch the measurement of the voltages at each test point of the generator shaft voltage.

[0043] A generator shaft voltage measurement conversion device disclosed in this embodiment further includes a box body, and the insulating board, the change-over switch, the steam end terminal, the large shaft grounding terminal, the exciting end terminal, the equipment grounding terminal, the DC switching switch, the AC switching switch, the DC voltmeter and the AC voltmeter are all located inside the box body.

[0044] The box body of this embodiment adopts a portable hand-held box; the insulating board and the various devices thereon are placed in the portable hand-held box for easy carrying and storage.

[0045] The transfer switch includes four positions, namely the open circuit position, the stator ground voltage measurement position at the steam end, the stator ground voltage measurement position at the exciter end, and the stator voltage measurement position from the steam end to the exciter end. When the transfer switch is in the open circuit position, there is no conduction between the input contacts and the output contacts of the changeover switch. When the transfer switch is in the stator ground voltage measurement position at the steam end, the stator ground voltage of the generator at the steam end can be measured by an AC voltmeter or a DC voltmeter. When the transfer switch is in the stator ground voltage measurement position at the exciter end, the stator ground voltage of the generator at the exciter end can be measured by an AC voltmeter or a DC voltmeter. When the transfer switch is in the stator voltage measurement position from the steam end to the exciter end, the stator voltage from the steam end to the exciter end of the generator can be measured by an AC voltmeter or a DC voltmeter.

[0046] The transfer switch also includes eight contacts, namely input contact 1, input contact 2, input contact 3, input contact 4, output contact 5, input contact 6, output contact 7, and input contact 8. Input contact 1 and input contact 3 are conductively connected. Input contact 2 and input contact 6 are conductively connected. Input contact 4 and input contact 8 are conductively connected. The circuits between input contact 1 and input contact 2, input contact 3 and input contact 4, output contact 5 and input contact 6, and output contact 7 and input contact 8 are connected and disconnected by controlling the transfer switch to be in different positions.

[0047] When the transfer switch is in the open circuit position, the circuits between input contact 1 and input contact 2, input contact 3 and input contact 4, output contact 5 and input contact 6, and output contact 7 and input contact 8 are not conductive. When the transfer switch is in the stator ground voltage measurement position at the steam end, the circuits between input contact 3 and input contact 4 and between output contact 5 and input contact 6 are conductive, and the circuits between input contact 1 and input contact 2 and between output contact 7 and input contact 8 are not conductive. When the transfer switch is in the stator ground voltage measurement position at the exciter end, the circuits between input contact 1 and input contact 2 and between input contact 3 and input contact 4 are not conductive, and the circuits between output contact 5 and input contact 6 and between output contact 7 and input contact 8 are conductive. When the transfer switch is in the stator voltage measurement position from the steam end to the exciter end, the circuits between input contact 1 and input contact 2 and between output contact 7 and input contact 8 are conductive, and the circuits between input contact 3 and input contact 4 and between output contact 5 and input contact 6 are not conductive.

[0048] The exciter terminal is connected to input contact 8. The large shaft grounding terminal is connected to input contact 6. The steam end terminal is connected to input contact 1. The two ends of the parallel circuit of the DC voltage measurement line and the AC voltage measurement line are respectively connected to output contact 5 and output contact 7.

[0049] The change-over switch in this embodiment adopts a four-position two-section universal change-over switch. Preferably, the LW5-16YH2 / 2 four-position two-section universal change-over switch is adopted, and the wiring configuration of this change-over switch is shown in the following table.

[0050]

[0051] In the table, 0 represents the off position; U 汽端 / 地 represents the measuring position of the shaft voltage between the steam end and the ground; U 励端 / 地 represents the measuring position of the shaft voltage between the excitation end and the ground; U 汽端 / 励端 represents the measuring position of the shaft voltage between the steam end and the excitation end.

[0052] By controlling the change-over switch to be in different positions in this embodiment, the measurement of the shaft voltage between the steam end of the generator and the ground, the shaft voltage between the excitation end and the ground, and the shaft voltage between the steam end and the excitation end can be realized. Its principle is the same as that of the three-phase voltage change-over switch connected in series in the bus voltage monitoring instrument in low-voltage power distribution, and it has good practical application performance.

[0053] By operating the change-over switch, the DC switching switch and the AC switching switch in this embodiment, the measurement of the DC shaft voltage and the AC shaft voltage at each point of the generator can be realized, without repeated wiring, saving the wiring layout work in the intermediate link. This not only simplifies the measurement process from complex to simple, but also effectively improves the work efficiency. The working hours for shaft voltage measurement are reduced by more than half compared with the traditional measurement method, and it has good economic benefits.

[0054] The process of measuring the shaft voltage of the generator by using a generator shaft voltage measurement conversion device disclosed in this embodiment includes:

[0055] When the voltage switching switch is in the off position, connect the steam end terminal and the excitation end terminal to the generator rotor; connect the large shaft grounding terminal to the large shaft grounding end of the generator rotor.

[0056] Turn the change-over switch to the measuring position of the shaft voltage between the steam end and the ground, close the AC switching switch, read and record the reading of the AC voltmeter, which is the AC shaft voltage between the steam end of the generator and the ground; after the value reading and recording are completed, disconnect the AC switching switch, turn the change-over switch to the measuring position of the shaft voltage between the excitation end and the ground, close the AC switching switch, read and record the reading of the AC voltmeter, which is the AC shaft voltage between the excitation end of the generator and the ground; after the value reading and recording are completed, disconnect the AC switching switch, turn the change-over switch to the measuring position of the shaft voltage between the steam end and the excitation end, close the AC switching switch, read and record the reading of the AC voltmeter, which is the AC shaft voltage between the steam end and the excitation end of the generator.

[0057] If it is necessary to measure the DC shaft voltage of the generator, after completing the above measurement of the AC shaft voltage of the generator; disconnect the AC switching switch, turn the change-over switch to the measurement position of the steam-end-to-earth shaft voltage, close the DC switching switch, read and record the reading of the DC voltmeter, which is the DC shaft voltage of the generator at the steam end to the earth; after the value reading and recording are completed, disconnect the DC switching switch, turn the change-over switch to the measurement position of the exciter-end-to-earth shaft voltage, close the DC switching switch, read and record the reading of the AC voltmeter, which is the DC shaft voltage of the generator at the exciter end to the earth; after the value reading and recording are completed, disconnect the DC switching switch, turn the change-over switch to the measurement position of the steam-end-to-exciter-end shaft voltage, close the DC switching switch, read and record the reading of the DC voltmeter, which is the DC shaft voltage of the generator from the steam end to the exciter end.

[0058] Embodiment 2

[0059] In this embodiment, a method for measuring the shaft voltage of a generator is disclosed, including:

[0060] Connect the steam-end terminal and the exciter-end terminal to the generator rotor;

[0061] Close the DC switching switch, disconnect the AC switching switch, and measure the DC shaft voltage of the generator through a DC voltmeter;

[0062] Disconnect the DC switching switch, close the AC switching switch, and measure the AC shaft voltage of the generator through an AC voltmeter.

[0063] Furthermore, when measuring the DC shaft voltage of the generator through a DC voltmeter or measuring the AC shaft voltage of the generator through an AC voltmeter, by switching the position of the change-over switch, measure the steam-end-to-earth shaft voltage, the exciter-end-to-earth shaft voltage, and the steam-end-to-exciter-end shaft voltage of the generator.

[0064] Furthermore, with the change-over switch in the off position, connect the steam-end terminal and the exciter-end terminal to the generator rotor.

[0065] Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. A generator shaft voltage measurement and conversion device, characterized in that: It includes an insulating plate; a conversion switch, a steam terminal terminal, a main shaft grounding terminal terminal, an excitation terminal terminal, a DC voltmeter and an AC voltmeter are arranged on the insulating plate; the steam terminal terminal and the excitation terminal terminal are both used to connect with the generator rotor; The excitation terminal terminal, the main shaft grounding terminal terminal and the steam terminal terminal terminal are all connected to the input contacts of the conversion switch; the DC voltmeter is connected in series with the DC switching switch to form a DC voltage measurement circuit, and the AC voltmeter is connected in series with the AC switching switch to form an AC voltage measurement circuit; the DC voltage measurement circuit and the AC voltage measurement circuit are connected in parallel and connected to the output contacts of the conversion switch; When the DC switching switch is closed and the AC switching switch is open, the DC shaft voltage of the generator can be measured by the DC voltmeter; when the DC switching switch is open and the AC switching switch is closed, the AC shaft voltage of the generator can be measured by the AC voltmeter.

2. A generator shaft voltage measurement and conversion device as claimed in claim 1, characterized in that: An equipment grounding terminal is also provided on the insulating board, and the equipment grounding terminal is used to connect to the earth.

3. A generator shaft voltage measurement and conversion device as claimed in claim 1, characterized in that: The conversion switch includes four gears, namely the opening gear, the steam end to ground shaft voltage measurement gear, the excitation end to ground shaft voltage measurement gear and the steam end to excitation end shaft voltage measurement gear; when the conversion switch is in the opening gear, there is no conduction between the input contacts and the output contacts of the switching switch; when the conversion switch is in the steam end to ground shaft voltage measurement gear, the steam end to ground shaft voltage of the generator can be measured by an AC voltmeter or a DC voltage; when the conversion switch is in the excitation end to ground shaft voltage measurement gear, the excitation end to ground shaft voltage of the generator can be measured by an AC voltmeter or a DC voltage; when the conversion switch is in the steam end to excitation end shaft voltage measurement gear, the steam end to excitation end shaft voltage of the generator can be measured by an AC voltmeter or a DC voltage.

4. A generator shaft voltage measurement and conversion device as claimed in claim 3, characterized in that: The transfer switch includes eight contacts, namely input contact 1, input contact 2, input contact 3, input contact 4, output contact 5, input contact 6, output contact 7 and input contact 8; input contact 1 and input contact 3 are connected and conductive; input contact 2 and input contact 6 are connected and conductive; input contact 4 and input contact 8 are connected and conductive; when the transfer switch is in the off position, the circuits between input contact 1 and input contact 2, input contact 3 and input contact 4, output contact 5 and input contact 6, and output contact 7 and input contact 8 are not conductive; when the transfer switch is in the steam-to-earth shaft voltage measurement position, the circuit between input contact 3 and input contact 4 and the circuit between output contact 5 and input contact 6 are conductive. The circuits between them are all connected, and the circuits between input contact 1 and input contact 2 and between output contact 7 and input contact 8 are not connected; when the conversion switch is in the gear for measuring the shaft voltage from the excitation end to the ground, the circuits between input contact 1 and input contact 2 and between input contact 3 and input contact 4 are not connected, and the circuits between output contact 5 and input contact 6 and between output contact 7 and input contact 8 are all connected; when the conversion switch is in the gear for measuring the shaft voltage from the steam end to the excitation end, the circuits between input contact 1 and input contact 2 and between output contact 7 and input contact 8 are all connected, and the circuits between input contact 3 and input contact 4 and between output contact 5 and input contact 6 are not connected.

5. A generator shaft voltage measurement and conversion device as claimed in claim 1, characterized in that: The utility model also comprises a box body, in which an insulating plate, a conversion switch, a steam terminal terminal, a main shaft grounding terminal terminal, an excitation terminal terminal, a DC voltmeter and an AC voltmeter are all located.

6. A generator shaft voltage measurement and conversion device as claimed in claim 1, characterized in that: The main shaft grounding terminal is used to connect to the main shaft grounding terminal of the generator rotor.

7. A generator shaft voltage measurement and conversion device as claimed in claim 1, characterized in that: The steam-end terminal post is connected to the steam-end terminal post; the excitation-end terminal post is connected to the excitation-end terminal post; the steam-end terminal post and the excitation-end terminal post are both used to connect to the generator rotor.

8. A method for measuring generator shaft voltage, characterized in that: include: Connect the steam-end terminal and the excitation-end terminal to the generator rotor; Close the DC switching switch, open the AC switching switch, and measure the DC shaft voltage of the generator using a DC voltmeter; Open the DC switching switch, close the AC switching switch, and measure the AC shaft voltage of the generator using an AC voltmeter.

9. A generator shaft voltage measurement method as claimed in claim 8, characterized in that: When the DC shaft voltage of the generator is measured by a DC voltmeter, or the AC shaft voltage of the generator is measured by an AC voltmeter, the steam end-to-ground shaft voltage, the excitation end-to-ground shaft voltage and the steam end-to-excitation end shaft voltage of the generator are measured by switching the gear of the conversion switch.

10. A generator shaft voltage measurement method as claimed in claim 8, characterized in that: When the transfer switch is in the open position, connect the steam-end terminal and the excitation-end terminal to the generator rotor.

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