Measuring device for large shaft current and large shaft voltage of hydraulic turbine set

Abstract

A measuring device for large shaft current and large shaft voltage of a hydraulic turbine set comprises a large shaft and a rotor, and further comprises a fault wave recording device and a first insulation brush holder arranged above the rotor, the fault wave recording device is provided with a voltage measuring winding, the first insulation brush holder is provided with a first carbon brush, one end of the first carbon brush is connected with the large shaft, and the other end of the first carbon brush is connected with a second carbon brush. The first carbon brush is connected with one end of a voltage measuring winding through a first cable, and the other end of the voltage measuring winding is grounded. The utility model is used for solving the problems that the fault of the large shaft insulation monitoring CT cannot be eliminated and the actual shaft voltage and the actual shaft current of the large shaft cannot be directly monitored in the existing shaft CT monitoring mode.

Description

Technical Field

[0001] The utility model relates to a device for measuring the large shaft current and large shaft voltage of a water turbine unit. Background Art

[0002] During operation, a hydro-turbine generator set experiences magnetic flux imbalance due to factors such as unequal air gaps (reluctance) between the stator and rotor, asymmetric stator core segmentation and pole configuration, and static excitation. This unbalanced magnetic flux interacts with the shaft, generating shaft voltage, which varies with the generator's voltage and load. The rotor shaft forms a loop through the carbon brushes and the water surface. This shaft voltage and the resulting shaft current accelerate the aging and deterioration of the bearing lubricant, leading to severe bearing burnout and, in severe cases, increased bearing runout.

[0003] The existing method of measuring shaft current is generally to install metal copper foil in the insulation layer of the shaft collar and the main shaft during the design of the hydro-turbine generator, dividing the shaft collar insulation into two sections, and then lead the copper foil to the metal ring on the main shaft surface with a wire. This structure and three carbon brushes are used to measure the insulation resistance between the main shaft and the copper foil, and between the copper foil and the shaft collar. The disadvantages are: (1) For hydro-turbine units without metal copper foil in the insulation layer of the shaft collar and the main shaft, the shaft CT monitoring method is used, and the failure of the main shaft insulation monitoring CT itself cannot be ruled out. (2) The actual shaft voltage and shaft current of the main shaft cannot be directly monitored. Utility Model Content

[0004] The purpose of the utility model is to provide a device for measuring the main shaft current and main shaft voltage of a hydro-turbine unit, which is used to solve the problems of the existing shaft CT monitoring method, which cannot eliminate the failure of the main shaft insulation monitoring CT itself and cannot directly monitor the actual shaft voltage and shaft current of the main shaft.

[0005] In order to solve the above problems, the technical solution of the utility model is:

[0006] A device for measuring large shaft current and shaft voltage includes a shaft and a rotor, as well as a fault recording device and a first insulating brush holder arranged above the rotor. The fault recording device is provided with a voltage measuring winding, and the first insulating brush holder is provided with a first carbon brush with one end connected to the shaft. The first carbon brush is connected to one end of the voltage measuring winding of the fault recording device through a first cable, and the other end of the voltage measuring winding is grounded.

[0007] A current measuring winding is provided on the fault recording device, a current transformer is provided on the main shaft, and the current transformer is connected to the current measuring winding of the fault recording device through a second cable.

[0008] A second insulating brush holder is provided under the rotor, a second carbon brush having one end connected to the main shaft is provided on the second insulating brush holder, the second carbon brush is connected to the primary grounding wire through a third cable, and a clamp meter is provided on the third cable.

[0009] The beneficial effects of the present invention are as follows: utilizing the output of the main shaft CT, as well as the output of the shaft voltage carbon brush and the shaft current carbon brush, the fault recording device realizes full-process monitoring of various operating conditions of the main shaft voltage and current; optimizing the structure of the main shaft grounding carbon brush to realize effective monitoring of the main shaft grounding current, and any abnormalities can be discovered in time and compared with the fault recording data, which is also convenient for subsequent waveform analysis, thereby ensuring the reliability of the operation of the main shaft insulation monitoring device and guaranteeing the safety of the unit operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention will be further described below with reference to the accompanying drawings:

[0011] Figure 1 It is a structural diagram of the present utility model.

[0012] In the figure: main shaft 1, current transformer 2, rotor 3, second carbon brush 4, second insulating brush holder 5, clamp meter 6, current measuring winding 7, voltage measuring winding 8, fault recording device 9, first insulating brush holder 10, first carbon brush 11. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0014] A device for measuring the shaft current and shaft voltage of a hydro turbine unit includes a shaft 1 and a rotor 3, a fault recording device 9, and a first insulating brush holder 10 arranged above the rotor 3. The fault recording device 9 is provided with a voltage measuring winding 8. The first insulating brush holder 10 is provided with a first carbon brush 11 connected to the shaft 1 at one end. The first carbon brush 11 passes through a 4mm 2 The first cable is connected to one end of the voltage measuring winding 8, and the other end of the voltage measuring winding 8 is grounded. Real-time monitoring and recording of the shaft voltage can be achieved.

[0015] The fault recording device 9 is provided with a current measuring winding 7, and a current transformer 2 is provided outside the main shaft 1. The current transformer 2 passes through a 1.5mm 2 The second cable is connected to the current measurement winding 7. This enables real-time monitoring and recording of the shaft CT current.

[0016] A second insulating brush holder 5 is provided below the rotor 3. A second carbon brush 4 is provided on the second insulating brush holder 5, one end of which is connected to the main shaft 1. The second carbon brush 4 passes through an 8mm 2The third cable is connected to the primary grounding wire, and a clamp meter 6 is provided on the third cable to realize real-time monitoring of the shaft current.

[0017] The contents described in the embodiments of this specification are merely an enumeration of the implementation forms of the utility model concept. The protection scope of the utility model should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the utility model also extends to equivalent technical means that can be thought of by those skilled in the art based on the concept of the utility model.

Claims

1. A device for measuring the main shaft current and main shaft voltage of a hydraulic turbine unit, comprising a main shaft (1) and a rotor (3), characterized in that: It also includes a fault recording device (9) and a first insulating brush holder (10) arranged above the rotor (3). The fault recording device (9) is provided with a voltage measuring winding (8). The first insulating brush holder (10) is provided with a first carbon brush (11) whose one end is connected to the main shaft (1). The first carbon brush (11) is connected to one end of the voltage measuring winding (8) through a first cable, and the other end of the voltage measuring winding (8) is grounded.

2. The device for measuring the large shaft current and large shaft voltage of a hydraulic turbine according to claim 1, characterized in that: A current measuring winding (7) is provided on the fault recording device (9), and a current transformer (2) is provided outside the main shaft (1). The current transformer (2) is connected to the current measuring winding (7) via a second cable.

3. The device for measuring the large shaft current and large shaft voltage of a hydraulic turbine according to claim 1 or 2, characterized in that: A second insulating brush holder (5) is provided below the rotor (3), a second carbon brush (4) having one end connected to the main shaft (1) is provided on the second insulating brush holder (5), the second carbon brush (4) is connected to the primary grounding wire via a third cable, and a clamp meter (6) is provided on the third cable.

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