Online monitoring method and system for magnetic pole air gap and shafting insulation resistance of generator

Abstract

The invention provides a generator magnetic pole air gap and shafting insulation impedance online monitoring method and system, and the method comprises the steps: connecting a high-frequency low-impedance inductor to a grounding brush lead, introducing a high-frequency excitation current source, and maintaining the low-frequency extremely low impedance of the grounding brush lead; an impedance transformer is introduced into each bearing part, a current path of the voltage of a high-frequency excitation signal introduced by a grounding electric brush in each bearing oil film impedance is blocked, and the influence of the impedance of an insulation loop on a magnetic pole air gap capacitor is shielded; monitoring the high-frequency voltage of the grounding brush and the high-frequency electricity of the large shaft, calculating the total capacitance of the magnetic pole air gap, and detecting the average air gap and dynamic air gap variation of the magnetic pole based on the capacitance; monitoring high and low frequency current of a power supply and an impedance transformer bypass and high and low frequency voltage and current of a large shaft, and calculating power frequency insulation impedance and capacitance values of each bearing. On-line monitoring of the average air gap amount and the dynamic change of the magnetic pole air gap can be realized, and meanwhile, the insulation resistance of each bearing of a shaft system can be monitored on line.

Description

Technical Field

[0001] The present application relates to the technical field of generator monitoring, and in particular to a method and system for online monitoring of a generator magnetic pole air gap and shaft insulation impedance. Background Art

[0002] Generators are important components of power equipment, and the insulation performance of their pole air gap and shaft system is crucial to the safe operation of the generator. Traditional detection of pole air gap and shaft insulation impedance mostly relies on regular inspection or manual measurement, and cannot achieve real-time monitoring. Due to external environmental interference, equipment aging and other factors, changes in pole air gap and shaft insulation impedance may cause equipment failure or damage. Therefore, how to achieve online monitoring of these key parameters is a technical problem that needs to be solved urgently. Summary of the invention

[0003] The present application aims to solve one of the technical problems in the related art at least to some extent.

[0004] To this end, the first objective of the present application is to provide an online monitoring method for generator pole air gap and shaft insulation impedance.

[0005] The second objective of the present application is to provide an online monitoring system for generator pole air gap and shaft insulation impedance.

[0006] The third objective of the present application is to provide an electronic device.

[0007] A fourth objective of the present application is to provide a computer-readable storage medium.

[0008] A fifth object of the present application is to provide a computer program product.

[0009] To achieve the above-mentioned purpose, the first embodiment of the present application proposes an online monitoring method for generator magnetic pole air gap and shaft insulation impedance, comprising:

[0010] Bypass the grounding brush lead wire around the high-frequency ferrite core or connect a high-frequency low-impedance inductor to the grounding brush lead wire, introduce a high-frequency excitation current source and keep the low-frequency extremely low impedance of the grounding brush lead wire;

[0011] Impedance transformers are introduced at various bearing locations to block the current path of the voltage of the high-frequency excitation signal introduced by the grounding brush in the oil film impedance of each bearing, thereby shielding the influence of the impedance of the insulation circuit on the pole air gap capacitance;

[0012] Monitor the high frequency voltage VSH of the ground brush H and large shaft high frequency current ISH H , calculate the total capacitance of the magnetic pole air gap, and detect the average magnetic pole air gap and dynamic air gap change based on the capacitance;

[0013] Monitors high and low frequency currents (I Hisol , I Lisol )、large shaft high and low frequency voltage (VSH H ,VSH L ) and current (IX H ,IX L ), calculate the power frequency insulation resistance and capacitance value of each bearing.

[0014] Optionally, the method of connecting a high-frequency low-impedance inductor to the grounding brush lead, introducing a high-frequency excitation current source and maintaining the low-frequency extremely low impedance of the grounding brush lead includes:

[0015] A special low-impedance high-frequency micro-inductor L1 is connected in series on the grounding brush lead, and the low impedance of the inductor and the water resistor Rw is used to access the high-frequency excitation current source, which is equivalent to the power frequency shaft voltage VSH L A low impedance high frequency voltage source VSH is superimposed on H The high-frequency excitation current source is used to provide sufficient high-frequency current excitation to ensure that the capacitance can be measured online and the change of the magnetic pole air gap can be detected.

[0016] Optionally, the impedance converter is used to:

[0017] The high and low frequency currents provided by the power supply only flow through the impedance Z of the insulating pad, thereby limiting the measurement of the high and low frequency currents to the insulating branch;

[0018] The high frequency excitation shaft voltage VSH is monitored by the internal frequency selection filter and amplifier circuit H , power frequency shaft voltage VSH L and the resulting bearing insulation current I Hisol , I Lisol ;

[0019] The capacitance C of the shaft system is calculated by the high-frequency component, and the impedance Z and resistance R of the shaft system are calculated by the power frequency component. The formula is:

[0020]

[0021] Among them, ω H is the angular frequency of the high-frequency excitation signal, ω L is the angular frequency of the power frequency signal.

[0022] Optionally, the change of water resistance Rw will cause the shunt of the magnetic pole equivalent capacitance IX0 H changes, and the high-frequency magnetic pole air gap voltage VSH in the large shaft is monitored at the same time H With current IX0 H , and calculate the pole air gap capacitance CRP, where:

[0023]

[0024] In order to eliminate the influence of water resistance changes, a high-frequency current coupler is installed to complete the high-frequency current ISH H The high-frequency current coupler is a Rogowski coil, and its induced electromotive force E is monitored to detect the high-frequency current ISH. H , the induced electromotive force contains the low-frequency component of the shaft current, and it is necessary to improve the signal-to-noise ratio of the high-frequency current through frequency selection filtering and amplifier;

[0025] The stability of the excitation source frequency is detected by a voltage-to-frequency converter to compensate for the error caused by frequency drift;

[0026] The calculation formula of the parameters involved is:

[0027]

[0028] B=μ 0 H

[0029]

[0030]

[0031] Among them, μ 0 is the vacuum magnetic permeability, R is the resistance of the current path, r is the radius of the induction coil, μ 0 is the vacuum permeability, S is the cross-sectional area of ​​the pole air gap, ε 0 is the dielectric constant of vacuum.

[0032] To achieve the above-mentioned purpose, the second embodiment of the present application proposes an online monitoring system for generator magnetic pole air gap and shaft insulation impedance, comprising:

[0033] The bearing insulation monitoring unit includes an upper guide bearing insulation monitoring unit, a lower guide bearing insulation monitoring unit, a thrust bearing insulation monitoring unit, and a water guide bearing insulation monitoring unit. Each bearing monitoring unit is used to monitor the insulation impedance of the upper guide bearing, the lower guide bearing, the thrust bearing, and the water guide bearing; each bearing insulation monitoring unit includes a first preamplifier and a digital signal processor;

[0034] The magnetic pole air gap monitoring unit is used to monitor the change of the magnetic pole air gap, and the magnetic pole air gap monitoring unit includes a second preamplifier and a digital signal processor;

[0035] The host computer system is connected to each monitoring unit via the RS485 network to carry out data sharing and remote data transmission.

[0036] Optionally, the first preamplifier is arranged at the bearing bushes of the upper guide, thrust, lower guide and water guide bearings respectively, and the second preamplifier is arranged at the grounding brush;

[0037] The first preamplifier includes an impedance converter, a frequency-selective filter amplifier and an ε r The first preamplifier is used to introduce the shaft voltage VSH from the shaft brush H and grounding point, introduce insulation impedance junction point from tile base or insulation tap, detect insulation impedance voltage VX H , VX L , Insulation resistance current I Hisol ,I Lisol ;

[0038] The second preamplifier includes a high-frequency current coupler and a frequency-selective filter amplifier for detecting the high-frequency current ISH H Proportional to the electromotive force E.

[0039] Optionally, the digital signal processor is used to:

[0040] Receive and process signals from various monitoring units, including pole air gap monitoring signals, voltage and current signals of various bearings of the shaft system, and electromotive force signals of high-frequency current couplers;

[0041] The signals of each monitoring unit are converted into digital form through multiple high-resolution A / D converters;

[0042] Calculate the insulation impedance, capacitance and resistance of each bearing part;

[0043] Calculate the pole air gap capacitance and extract the pole air gap quantity;

[0044] Perform spectrum analysis on shaft voltage signal and air gap signal to extract their mean value, dynamic variation and harmonic components;

[0045] The real-time monitoring data is generated by processing the results and transmitted to the upper computer system through the RS485 communication network for data sharing and remote monitoring.

[0046] To achieve the above-mentioned purpose, the third aspect of the present application provides an electronic device, including: a processor, and a memory communicatively connected to the processor;

[0047] The memory stores computer-executable instructions;

[0048] The processor executes the computer-executable instructions stored in the memory to implement the method as described in any one of the first aspects.

[0049] To achieve the above-mentioned purpose, the fourth aspect embodiment of the present application proposes a computer-readable storage medium, in which computer-readable storage medium is stored computer execution instructions, and when the computer execution instructions are executed by a processor, they are used to implement the method as described in any one of the first aspects.

[0050] To achieve the above-mentioned purpose, the fifth aspect of the present application proposes a computer program product, which implements any method in the first aspect when executed by a processor.

[0051] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0052] (1) The monitoring method and system proposed in the present application can monitor the changes in the generator pole air gap and the insulation impedance of the bearings of each part of the shaft system in real time and online, which helps to detect abnormal conditions of the equipment in a timely manner and improve the reliability and operation safety of the equipment.

[0053] (2) By introducing a high-frequency low-impedance inductor into the grounding brush lead and an impedance transformer into the bearing part, the present application can effectively improve the monitoring sensitivity of the magnetic pole air gap capacitance, shield the influence of the impedance of the insulation circuit on the magnetic pole air gap capacitance, and ensure more accurate monitoring results.

[0054] (3) The present application can accurately calculate the power frequency insulation impedance, capacitance value and pole air gap capacitance of each bearing, and detect the average air gap and dynamic air gap change of the pole based on these calculated values.

[0055] (4) By installing a high-frequency current coupler to monitor the high-frequency current and combining it with a frequency-selective filter, the present application can effectively eliminate the influence of interference sources such as water resistance and ensure the accuracy of the monitoring results.

[0056] (5) By designing an integrated monitoring unit, the various monitoring units in this application are connected through an RS485 network, which enables data sharing and remote data transmission. Through the host computer system, real-time viewing and analysis of the monitoring data can be achieved, thereby improving the efficiency of equipment maintenance and management.

[0057] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0059] Figure 1 A schematic flow chart of an online monitoring method for a generator magnetic pole air gap and shaft insulation impedance provided by an embodiment of the present application;

[0060] Figure 2 A schematic diagram of a physical model of magnetic pole air gap monitoring and bearing insulation provided in an embodiment of the present application;

[0061] Figure 3 Structural schematic diagram of an on - line monitoring method for generator pole air gap and shafting insulation impedance provided by an embodiment of the present application;

[0062] Figure 4 Structural schematic diagram of a pre - amplifier provided by an embodiment of the present application;

[0063] Figure 5 Structural schematic diagram of a digital signal processor provided by an embodiment of the present application. Specific embodiments

[0064] The following details the embodiments of the present application. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as a limitation to the present application.

[0065] In view of the problems existing in the prior art, an embodiment of the present application provides an on - line monitoring method for generator pole air gap and shafting insulation impedance. Figure 1 Flow schematic diagram of a XX method provided by an embodiment of the present application. As Figure 1 shown, the method includes the following steps:

[0066] Step 101: Wind the grounding brush lead around a high - frequency ferrite core or connect a high - frequency low - impedance inductor to the grounding brush lead, introduce a high - frequency excitation current source, and maintain a very low impedance of the grounding brush lead at low frequencies.

[0067] In an embodiment of the present application, step 101 involves winding the grounding brush lead around a high - frequency ferrite core or connecting a high - frequency low - impedance inductor to the grounding brush lead. The main purpose of this operation is to ensure that the grounding brush lead has a very low impedance at low frequencies by introducing a high - frequency excitation current source, and at the same time maintain sufficient impedance in the high - frequency range to ensure the smooth transmission of high - frequency signals.

[0068] Specifically, referring to Figure 2 , in order to connect a high - frequency excitation current source IGH(9) to the grounding brush lead and maintain a very low impedance of the grounding brush lead at low frequencies while increasing its high - frequency impedance, the method is to wind the grounding brush lead around a high - frequency ferrite core to form a high - frequency micro - inductor or directly connect a special low - impedance high - frequency micro - inductor L1(10) in series. The inductor L1 and the water resistance Rw are used in combination to connect a low - impedance current to the high - frequency excitation current source, equivalently superimposing a low - impedance high - frequency voltage source VSH L on the power - frequency shaft voltage VSH HDue to the characteristics of the water resistor Rw, its low impedance effect will not affect the transmission of low-frequency signals, ensuring that the grounding brush lead can continue to complete the electrostatic discharge function. At high frequencies, this configuration effectively introduces a high-frequency voltage source VSH H This enables current excitation to measure capacitance online and further detect changes in the pole air gap.

[0069] This configuration in the embodiment of the present application ensures the stability of the high-frequency signal and the current source during the measurement process, thereby improving the measurement accuracy and sensitivity, thereby enabling real-time monitoring of changes in the magnetic pole air gap.

[0070] Step 102, introducing impedance transformers at various bearing locations to block the current path of the voltage of the high-frequency excitation signal introduced by the grounding brush in the oil film impedance of each bearing location, thereby shielding the influence of the impedance of the insulation circuit on the pole air gap capacitance.

[0071] In the embodiments of this application, refer to Figure 2 , step 102 requires the introduction of an impedance transformer (1) at each bearing part. The function of the impedance transformer is to block the current path of the high-frequency excitation signal introduced by the grounding brush in the oil film impedance of each bearing part by changing the signal path. The advantage of this is that it effectively shields the influence of the impedance of the insulation circuit on the magnetic pole air gap capacitance, and avoids the interference of the electrical performance of the bearing part on the air gap monitoring result.

[0072] The role of the impedance transformer here is to convert the high-frequency current ISH passing through each bearing H The impedance transformer is isolated from the insulated branch and returns to the ground through the impedance transformer and the current provided by the power supply. In this way, the impedance transformer not only reduces the signal interference in the system, but also improves the accuracy and stability of the measurement, especially in the problem of high-frequency current shunt.

[0073] Step 103, monitoring the high frequency voltage VSH of the grounding brush H and large shaft high frequency current ISH H , calculate the total capacitance of the magnetic pole air gap, and detect the average magnetic pole air gap and dynamic air gap change based on the capacitance.

[0074] In the embodiment of the present application, step 103 involves monitoring the high frequency voltage VSH of the ground brush. H and the high frequency current ISH of the large shaft H The purpose of this process is to calculate the total capacitance of the magnetic pole air gap. By measuring the changes in current and voltage, the capacitance value of the magnetic pole air gap can be effectively extracted. Through the calculation of this capacitance, the average air gap value of the magnetic pole can be obtained. And the dynamic change of the pole air gap Δd.

[0075] This step in the embodiment of the present application utilizes real-time monitoring of high-frequency current and voltage to accurately calculate the pole air gap capacitance, and analyzes the state of the pole air gap based on the capacitance change. Through this method, the change of the air gap can be dynamically monitored, providing important real-time data for the operation of the generator.

[0076] Step 104, monitoring the high and low frequency currents (I Hisol , I Lisol )、large shaft high and low frequency voltage (VSH H ,VSH L ) and current (IX H ,IX L ), calculate the power frequency insulation impedance and capacitance value of each bearing, and calculate the pole air gap capacitance CRP, average air gap And parameters such as dynamic air gap change Δd and insulation branch impedance Z.

[0077] In the embodiment of the present application, the key to step 104 is to monitor the high and low frequency currents (I Hisol , I Lisol )、large shaft high and low frequency voltage (VSH H ,VSH L ) and current (IX H ,IX L ). By monitoring these signals, the power frequency insulation impedance and capacitance of each bearing can be calculated. This process can not only calculate the capacitance of the bearing, but also accurately extract the insulation impedance Z and resistance R of each bearing.

[0078] In addition, based on the above monitoring and calculation results, the pole air gap capacitance CRP, average air gap Parameters such as the dynamic air gap change Δd and the insulation branch impedance Z can also be accurately calculated, which is of great significance for evaluating the operating status and health of the generator.

[0079] In the embodiment of the present application, the main function of the impedance converter (1) is to guide the high and low frequency currents provided by the power supply only through the impedance Z of the insulating pad, thereby ensuring that the current flows only in the insulating loop without affecting other areas. The frequency selection filter and amplification circuit (2-6) equipped inside the impedance converter can accurately separate and amplify signals of different frequencies, thereby monitoring the high frequency excitation shaft voltage VSH H , power frequency shaft voltage VSH L and the resulting bearing insulation current I Hisol , I Lisol .

[0080] Specifically, the capacitance C of the shafting is calculated through the high-frequency component, and the impedance Z and resistance R of the shafting are calculated through the power-frequency component. The formulas are as follows:

[0081]

[0082]

[0083] where ω H is the angular frequency of the high-frequency excitation signal, and ω L is the angular frequency of the power-frequency signal.

[0084] It should be noted that to ensure the accuracy of the calculation, all these calculations need to be carried out at specific frequencies ω H and ω L . Therefore, it is necessary to be able to process high-frequency signals and power-frequency signals simultaneously and perform spectrum analysis in order to extract accurate voltage and current data from them and avoid errors caused by frequency changes.

[0085] In the embodiment of the present application, referring to Figure 2 , the change of the water resistance Rw(11) will cause the shunt current IX0 H of the magnetic pole equivalent capacitance to change, which makes the water resistance a source of interference. Therefore, in order to accurately monitor the change of the magnetic pole air gap, it is necessary to eliminate the influence brought by the change of the water resistance Rw. In order to simultaneously monitor the high-frequency magnetic pole air gap voltage VSH H and the current IX0 H in the large shaft and calculate the magnetic pole air gap capacitance CRP, where:

[0086]

[0087] To eliminate this interference, the present application introduces a high-frequency current coupler (8), which is a Rogowski coil. By monitoring its induced electromotive force E, the high-frequency current ISH H can be detected. This method can directly measure the high-frequency current in the shafting through the high-frequency current coupler, avoiding the influence of the high-frequency current passing through the bearing branch. This monitoring method ensures the accurate capture of the high-frequency signals in the shafting and avoids interference from the bearings.

[0088] In addition, the influence of the frequency stability on the calculation result is in a square relationship. Therefore, the present application introduces a voltage-frequency converter to detect the stability of the excitation source frequency and compensate for the error caused by frequency drift, thereby improving the calculation accuracy.

[0089] It should be noted that the induced electromotive force not only contains high-frequency current components, but also may contain a certain amount of low-frequency components of shaft current, especially the power frequency interference that may exist on site. In order to improve the accuracy and signal-to-noise ratio of the measurement signal, it is necessary to use frequency-selective filters and amplifiers to further improve the signal-to-noise ratio of the high-frequency current, thereby obtaining a clearer high-frequency signal.

[0090] The basic algorithm used in the embodiments of the present application is as follows:

[0091]

[0092] This is the formula for calculating the magnetic field strength H, where I H is the high frequency current and R is the resistance of the current path.

[0093] B=μ 0 H

[0094] This formula is used to calculate the magnetic field strength B, where μ 0 is the vacuum permeability, and H is the magnetic field strength calculated previously.

[0095]

[0096] Here S is the cross-sectional area of ​​the pole air gap, is the magnetic flux and r is the radius of the induction coil.

[0097]

[0098] This formula is used to calculate the induced electromotive force E, where ω is the angular frequency of the excitation signal, N is the number of turns of the induction coil, r is the radius of the coil, and I H is the current through the coil.

[0099]

[0100] This formula calculates the high-frequency current I through the induced electromotive force E H , and through the constant simplify.

[0101] Finally, the pole air gap capacitance C RP The calculation formula of the magnetic pole air gap d is:

[0102]

[0103] Among them, μ 0 is the vacuum magnetic permeability, R is the resistance of the current path, μ 0 is the vacuum permeability, S is the cross-sectional area of ​​the pole air gap, ε 0 is the dielectric constant of vacuum.

[0104] Through this series of calculations, the change in the magnetic pole air gap can be accurately detected, further improving the monitoring accuracy and sensitivity of the system.

[0105] In order to implement the above-mentioned embodiment, the present application also proposes an online monitoring system for the generator magnetic pole air gap and shaft insulation impedance. Figure 3 The schematic diagram of the structure of an online monitoring system for the magnetic pole air gap and shaft insulation impedance of a generator provided in an embodiment of the present application. Figure 3 As shown, the system comprises: a magnetic pole air gap monitoring unit (12), an upper guide bearing insulation monitoring unit (13), a lower guide bearing insulation monitoring unit (14), a thrust bearing insulation monitoring unit (15), a water guide bearing insulation monitoring unit (16) and a host computer system (17).

[0106] In the embodiment of the present application, each bearing monitoring unit is used to monitor the insulation impedance of the upper guide bearing, the lower guide bearing, the thrust bearing and the water guide bearing; each bearing insulation monitoring unit includes a first preamplifier and a digital signal processor; the magnetic pole air gap monitoring unit is used to monitor the change of the magnetic pole air gap, and the magnetic pole air gap monitoring unit includes a second preamplifier and a digital signal processor. The upper computer system is connected to each monitoring unit through an RS485 network for data sharing and remote data transmission.

[0107] In one embodiment of the present application, the measurement point and sensor arrangement process is as follows: The grounding brush lead is wound around the ferrite to form a high-frequency micro-inductor L 1 (1) (10-100uH); Arrange a preamplifier A for each bearing in the oil tank of each part to transform the impedance and detect the insulation impedance; Arrange a reference capacitor C in the oil tank of each part ref and ε r Detector for measuring dielectric constant ε r ; A high-frequency current coupler and a frequency-selective amplifier are arranged on the upper side of the grounding brush.

[0108] like Figure 3 As shown, the preamplifier includes a preamplifier 1 for bearing monitoring and a preamplifier 2 for high-frequency shaft current detection, namely, a first preamplifier and a second preamplifier. The preamplifier 1 is arranged at the bearing bushes of the upper guide, thrust, lower guide and water guide bearings, respectively, and the preamplifier 2 is arranged at the grounding brush.

[0109] In the embodiment of the present application, the preamplifier 1 includes an impedance converter (1), a frequency selective filter amplifier H (2, 4), a frequency selective filter amplifier L (3, 5), ε r Detector (6), preamplifier 1 is used to introduce shaft voltage VSH from the shaft brush H and grounding point, introduce insulation impedance junction point from tile base or insulation tap, detect insulation impedance voltage VX H , VX L, Insulation resistance current I Hisol ,I Lisol The preamplifier 2 includes a high-frequency current coupler (8) and a frequency-selective filter amplifier H (7) for detecting the high-frequency current ISH. H Proportional to the electromotive force E.

[0110] like Figure 4 As shown, the detection signal (VSH) of each bearing position H ,VSH L , I Hisol , I Lisol , V ε ), and the detection signal ISH of the high-frequency current coupler H , respectively, through shielded cables to their respective digital signal processing units C, and through multiple high-resolution A / D to complete analog-to-digital conversion, the CPU calculates the insulation impedance z and capacitance (c isol , c oil )、Resistance(r isol , r oil ), calculate the pole air gap capacitance and the pole air gap amount. Furthermore, the digital signal processing unit C also performs spectrum analysis on the shaft voltage and air gap amount, extracts the mean value, dynamic change amount and each harmonic component. The digital signal processor can form an on-site RS485 network, transmit data to the upper computer system, carry out data sharing and remote monitoring, and meet the functional requirements of multi-channel online monitoring, data sharing, remote transmission, etc.

[0111] In order to implement the above embodiments, the present application also proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0112] In order to implement the above embodiments, the present application also proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided by the above embodiments.

[0113] In order to implement the above embodiments, the present application also proposes a computer program product, including a computer program, which implements the methods provided by the above embodiments when executed by a processor.

[0114] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in this application are in compliance with relevant laws and regulations and do not violate public order and good morals.

[0115] It should be noted that personal information from users should be collected for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. In addition, such collection / sharing should be carried out after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign the agreement / authorization including authorization of relevant user information before the user uses the function. In addition, any necessary steps should be taken to protect and safeguard access to such personal information data and ensure that others who have access to personal information data comply with its privacy policy and procedures.

[0116] The present application is expected to provide an implementation scheme for users to selectively block the use or access of personal information data. That is, the present disclosure is expected to provide hardware and / or software to prevent or block access to such personal information data. Once the personal information data is no longer needed, the risk can be minimized by limiting data collection and deleting the data. In addition, when applicable, such personal information is de-identified to protect the privacy of the user.

[0117] In the description of the aforementioned embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0118] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0119] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0120] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0121] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0122] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0123] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0124] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

[0125] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this application can be executed in parallel, sequentially or in different orders, as long as the expected results of the technical solution of this application can be achieved, and this document is not limited here.

[0126] The above specific implementations do not constitute a limitation on the protection scope of this application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. A method for online monitoring of generator magnetic pole air gap and shaft insulation impedance, characterized in that: The following steps are involved: Bypass the grounding brush lead wire around the high-frequency ferrite core or connect a high-frequency low-impedance inductor to the grounding brush lead wire, introduce a high-frequency excitation current source and keep the low-frequency extremely low impedance of the grounding brush lead wire; Impedance transformers are introduced at various bearing locations to block the current path of the voltage of the high-frequency excitation signal introduced by the grounding brush in the oil film impedance of each bearing, thereby shielding the influence of the impedance of the insulation circuit on the pole air gap capacitance; Monitor the high frequency voltage VSH of the ground brush H and large shaft high frequency current ISH H , calculate the total capacitance of the magnetic pole air gap, and detect the average magnetic pole air gap and dynamic air gap change based on the capacitance; Monitors high and low frequency currents (I Hisol , I Lisol )、large shaft high and low frequency voltage (VSH H ,VSH L ) and current (IX H ,IX L ), calculate the power frequency insulation resistance and capacitance value of each bearing.

2. The method according to claim 1, characterized in that The method of connecting a high-frequency low-impedance inductor to the grounding brush lead, introducing a high-frequency excitation current source and maintaining the low-frequency extremely low impedance of the grounding brush lead includes: A special low-impedance high-frequency micro-inductor L1 is connected in series on the grounding brush lead, and the low impedance of the inductor and the water resistor Rw is used to access the high-frequency excitation current source, which is equivalent to the power frequency shaft voltage VSH L A low impedance high frequency voltage source VSH is superimposed on H The high-frequency excitation current source is used to provide sufficient high-frequency current excitation to ensure that the capacitance can be measured online and the change of the magnetic pole air gap can be detected.

3. The method according to claim 2, characterized in that The impedance converter is used for: The high and low frequency currents provided by the power supply only flow through the impedance Z of the insulating pad, thereby limiting the measurement of the high and low frequency currents to the insulating branch; The high frequency excitation shaft voltage VSH is monitored by the internal frequency selection filter and amplifier circuit H , power frequency shaft voltage VSH L and the resulting bearing insulation current I Hisol , I Lisol ; The capacitance C of the shaft system is calculated by the high-frequency component, and the impedance Z and resistance R of the shaft system are calculated by the power frequency component. The formula is: Among them, ω H is the angular frequency of the high-frequency excitation signal, ω L is the angular frequency of the power frequency signal.

4. The method according to claim 3, characterized in that Also includes: The change of water resistance Rw will cause the shunt IX0 of the magnetic pole equivalent capacitance H changes, and the high-frequency magnetic pole air gap voltage VSH in the large shaft is monitored at the same time H With current IX0 H , and calculate the pole air gap capacitance CRP, where: In order to eliminate the influence of water resistance changes, a high-frequency current coupler is installed to complete the high-frequency current ISH H The high-frequency current coupler is a Rogowski coil, and its induced electromotive force E is monitored to detect the high-frequency current ISH. H , the induced electromotive force contains the low-frequency component of the shaft current, and it is necessary to improve the signal-to-noise ratio of the high-frequency current through frequency selection filtering and amplifier; The stability of the excitation source frequency is detected by a voltage-to-frequency converter to compensate for the error caused by frequency drift; The calculation formula of the parameters involved is: B=μ0H Where μ0 is the magnetic permeability of vacuum, R is the resistance of the current path, r is the radius of the induction coil, μ0 is the magnetic permeability of vacuum, S is the cross-sectional area of ​​the pole air gap, and ε0 is the dielectric constant of vacuum.

5. An online monitoring system for generator magnetic pole air gap and shaft insulation impedance, characterized in that: It includes a magnetic pole air gap monitoring unit, a bearing insulation monitoring unit and a host computer system, wherein: The bearing insulation monitoring unit includes an upper guide bearing insulation monitoring unit, a lower guide bearing insulation monitoring unit, a thrust bearing insulation monitoring unit, and a water guide bearing insulation monitoring unit. Each bearing monitoring unit is used to monitor the insulation impedance of the upper guide bearing, the lower guide bearing, the thrust bearing, and the water guide bearing; each bearing insulation monitoring unit includes a first preamplifier and a digital signal processor; The magnetic pole air gap monitoring unit is used to monitor the change of the magnetic pole air gap, and the magnetic pole air gap monitoring unit includes a second preamplifier and a digital signal processor; The host computer system is connected to each monitoring unit via the RS485 network to carry out data sharing and remote data transmission.

6. The system according to claim 5, characterized in that The first preamplifier is arranged at the bearing bushes of the upper guide, thrust, lower guide and water guide bearings respectively, and the second preamplifier is arranged at the grounding brush; The first preamplifier includes an impedance converter, a frequency-selective filter amplifier and an ε r The first preamplifier is used to introduce the shaft voltage VSH from the shaft brush H and grounding point, introduce insulation impedance junction point from tile base or insulation tap, detect insulation impedance voltage VX H , VX L , Insulation resistance current I Hisol ,I Lisol ; The second preamplifier includes a high-frequency current coupler and a frequency-selective filter amplifier for detecting the high-frequency current ISH H Proportional to the electromotive force E.

7. The system according to claim 6, characterized in that The digital signal processor is used for: Receive and process signals from various monitoring units, including pole air gap monitoring signals, voltage and current signals of various bearings of the shaft system, and electromotive force signals of high-frequency current couplers; The signals of each monitoring unit are converted into digital form through multiple high-resolution A / D converters; Calculate the insulation impedance, capacitance and resistance of each bearing part; Calculate the pole air gap capacitance and extract the pole air gap quantity; Perform spectrum analysis on shaft voltage signal and air gap signal to extract their mean value, dynamic variation and harmonic components; The real-time monitoring data is generated by processing the results and transmitted to the upper computer system through the RS485 communication network for data sharing and remote monitoring.

8. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 4.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 4 when executed by a processor.

10. A computer program product, characterized in that The invention comprises a computer program, which implements the method according to any one of claims 1 to 4 when being executed by a processor.

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