On-line monitoring system for shaft voltage and shaft current

Abstract

The utility model discloses a shaft voltage and shaft current on-line monitoring system, which relates to generator shaft voltage and shaft current monitoring and comprises a signal acquisition module, a signal processing module, a display module, an alarm module and a storage module. The signal acquisition module acquires a shaft voltage signal and a shaft current signal of the generator and sends the signals to the signal processing module, the storage module and the display module respectively; the signal processing module performs fast Fourier transform and filtering on the shaft voltage signal and the shaft current signal to obtain a processed voltage signal and a processed current signal, and sends the processed voltage signal and the processed current signal to the alarm module, the storage module and the display module; and the alarm module gives an alarm according to the processed voltage signal, the processed current signal and a preset threshold value, and sends an alarm moment signal to the storage module. According to the utility model, the monitoring accuracy of shaft voltage and shaft current can be improved, accurate fault alarm can be carried out, and safe operation of a generator can be ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to generator shaft voltage shaft current monitoring technical field more specifically relates to a kind of shaft voltage shaft current on-line monitoring system. BACKGROUND

[0002] With the rapid development of modern industry, large generator set is increasingly important in power system. As the core equipment of energy conversion, the reliability and safety of generator operation is directly related to the stability of the entire power system.

[0003] In the process of generator operation, shaft voltage and shaft current are the key indicators to measure its mechanical state. High shaft voltage and shaft current can cause shaft insulation damage, and then cause serious equipment accidents. Therefore, on-line monitoring of generator shaft voltage and shaft current, early detection and prevention of potential failure, to ensure the safe operation of generator set, reduce maintenance cost has important significance. However, the existing shaft voltage and shaft current monitoring system has the disadvantages of insufficient monitoring accuracy, poor system stability and inaccurate alarm.

[0004] Therefore, how to improve the monitoring accuracy of shaft voltage and shaft current, and accurate fault alarm is a problem to be solved by those skilled in the art. UTILITY MODEL CONTENTS

[0005] Therefore, the utility model provides a kind of shaft voltage shaft current on-line monitoring system to solve the problems in the background art.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] The utility model discloses a kind of shaft voltage shaft current on-line monitoring system, comprising: signal acquisition module, signal processing module, display module, alarm module, storage module;

[0008] The signal acquisition module is respectively electrically connected with the signal processing module, display module and storage module, acquires generator shaft voltage signal and shaft current signal, and sends to the signal processing module, storage module and display module respectively;

[0009] The signal processing module is respectively electrically connected with the display module, the alarm module and the storage module, and the shaft voltage signal and the shaft current signal are subjected to fast Fourier transform and filtering, to obtain processing voltage signal and processing current signal, and sent to the alarm module, the storage module and the display module;

[0010] The shaft voltage signal and the shaft current signal, and the processing voltage signal and the processing current signal, are displayed by the display module, and stored by the storage module.

[0011] The alarm module is electrically connected with the storage module, and issues an alarm according to the processed voltage signal and the processed current signal and a preset threshold value, and sends a time signal of the alarm to the storage module.

[0012] Further, the signal acquisition module comprises a sensor unit and a transmitter unit.

[0013] The sensor unit comprises a voltage sensor and an axial current transformer, input and output terminals of the voltage sensor are connected with an excitation end brush and a steam end grounding point respectively, the voltage sensor detects an axial voltage between the excitation end and the steam end to obtain an initial axial voltage signal, and the axial current transformer detects a size of a steam end axial grounding current to obtain an initial axial current signal.

[0014] The transmitter unit receives the initial axial voltage signal and the initial axial current signal, and converts the signals into standard 0-5VAC signals to obtain the axial voltage signal and the axial current signal.

[0015] Further, the signal processing module comprises a Fourier transform unit and a filter unit.

[0016] The Fourier transform unit performs fast Fourier transform on the axial voltage signal and the axial current signal and sends the signals to the filter unit, and the filter unit filters the signals after the Fourier transform to obtain the processed voltage signal and the processed current signal.

[0017] Further, the alarm module comprises a voltage threshold value comparison unit, a first timing unit, a current threshold value comparison unit, a second timing unit, and an alarm unit.

[0018] The voltage threshold value comparison unit compares the processed voltage signal with a set threshold value in real time, outputs a high level to the first timing unit when the voltage signal exceeds a set range, the first timing unit starts timing when receiving the high level, and issues a voltage alarm signal when a time length is greater than a set threshold value.

[0019] The current threshold value comparison unit compares the processed current signal with a set threshold value in real time, outputs a high level to the second timing unit when the current signal exceeds a set range, the second timing unit starts timing when receiving the high level, and issues a current alarm signal when a time length is greater than a set threshold value.

[0020] The alarm unit issues a corresponding alarm according to the received voltage alarm signal and / or the current alarm signal, and sends an alarm time signal to the storage module.

[0021] Further, the voltage threshold comparison unit comprises a high voltage register, a low voltage register, a real-time voltage register and a first comparator, and the first timing unit comprises a first timer and a second timer;

[0022] The high voltage register and the low voltage register respectively store threshold values of high-axis voltage alarm signals and low-axis voltage alarm signals, and the real-time voltage register stores a value which is updated in real time according to a voltage effective value of the processed voltage signal;

[0023] The first comparator compares the value stored in the real-time voltage register with the value stored in the high voltage register, and when the value stored in the real-time voltage register is greater, a high level is sent to the first timer, and the first timer starts timing, and when the time length is greater than a set threshold value, a high-axis voltage alarm signal is sent;

[0024] The first comparator compares the value stored in the real-time voltage register with the value stored in the low voltage register, and when the value stored in the real-time voltage register is smaller, a high level is sent to the second timer, and the first timer starts timing, and when the time length is greater than a set threshold value, a low-axis voltage alarm signal is sent.

[0025] Further, the current threshold comparison unit comprises a first high current register, a second high current register, a low current register, a real-time current register and a second comparator, and the second timing unit comprises a third timer, a fourth timer and a fifth timer;

[0026] The first high current register, the second high current register and the low current register respectively store threshold values of a first high-axis current signal, a second high-axis current signal and a low-axis current alarm signal, and the real-time current register stores a value which is updated in real time according to a current effective value of the processed current signal;

[0027] The second comparator compares the value stored in the real-time current register with the value stored in the first high current register, and when the value stored in the real-time current register is greater, a high level is sent to the third timer, and the third timer starts timing, and when the time length is greater than a set threshold value, the first high-axis current signal is sent;

[0028] The second comparator compares the value stored in the real-time current register with the value stored in the second high current register, and when the value stored in the real-time current register is greater, a high level is sent to the fourth timer, and the fourth timer starts timing, and when the time length is greater than a set threshold value, the second high-axis current signal is sent;

[0029] The second comparator compares the value stored in the real-time current register with the value stored in the low current register, and when the value stored in the real-time current register is smaller, a high level is sent to the fifth timer, and the fifth timer starts timing, and when the time length is greater than a set threshold, the low shaft current alarm signal is sent.

[0030] Further, the voltage alarm signal includes a high shaft voltage alarm signal and a low shaft voltage alarm signal, and the current alarm signal includes a first-level high shaft current signal, a second-level high shaft current signal and a low shaft current signal.

[0031] When the voltage effective value of the processed voltage signal is greater than 10v and the time length is greater than 6 seconds, the high shaft voltage alarm signal is sent; and when the voltage effective value of the processed voltage signal is less than 0.5v and the time length is greater than 60 seconds, the low shaft voltage alarm signal is sent.

[0032] When the current effective value of the processed current signal is greater than 0.1A and the time length is greater than 15 minutes, the first-level high shaft current signal is sent; when the current effective value of the processed current signal is greater than 1A and the time length is greater than 3 seconds, the second-level high shaft current signal is sent; and when the current effective value of the processed current signal is less than 0.1A (the low shaft current comparison alarm logic is a shaft current bypass system hardware test logic, which can be separately set with a threshold value and a delay time), and the time length is greater than 2 seconds, the low shaft current signal is sent.

[0033] Further, the alarm includes an interface LED light / screen cabinet panel indicator light alarm and a passive node alarm.

[0034] According to the above technical solution, compared with the prior art, the shaft voltage shaft current online monitoring system can effectively extract effective information in the shaft voltage and shaft current signals, reduce noise interference, and improve monitoring accuracy; the system can collect and process shaft voltage and shaft current signals in real time, timely send alarms, ensure that measures can be taken quickly when potential faults occur, and ensure the safe operation of the generator set; the set multi-level alarm threshold can send alarms of different levels according to different fault severity, so that the operator can quickly judge the severity of the fault. The utility model can improve the monitoring accuracy of shaft voltage and shaft current, accurately alarm faults, and ensure the safe operation of the generator. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only a part of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0036] Figure 1 The figure is a schematic diagram of the overall structure provided by the present application.

[0037] Figure 2 The figure is a schematic diagram of the direct display result of the collected signal provided by the present application. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0039] The embodiment of the present application discloses an online monitoring system for shaft voltage and shaft current, as shown in the figure, comprising: a signal acquisition module, a signal processing module, a display module, an alarm module, a storage module; Figure 1

[0040] The signal acquisition module is electrically connected with the signal processing module, the display module and the storage module, respectively, acquires the generator shaft voltage signal and the shaft current signal, and sends them to the signal processing module, the storage module and the display module, respectively;

[0041] The signal processing module is electrically connected with the display module, the alarm module and the storage module, respectively, performs fast Fourier transform and filtering on the shaft voltage signal and the shaft current signal, obtains the processed voltage signal and the processed current signal, and sends them to the alarm module, the storage module and the display module;

[0042] The shaft voltage signal and the shaft current signal, and the processed voltage signal and the processed current signal, are all displayed through the display module and stored through the storage module;

[0043] The alarm module is electrically connected with the storage module, sends an alarm according to the processed voltage signal and the processed current signal, and a preset threshold value, and sends the time signal of the alarm to the storage module.

[0044] ​Specifically, during the operation of the generator, the shaft voltage and shaft current signals are collected in real time and dynamically with high precision by AD, and the shaft voltage and shaft current waveforms are displayed, processed, judged and alarmed synchronously, and the data are stored with high reliability, thereby improving the real-time dynamic processing capability of the system and forming a high-performance and high-stability generator shaft voltage and shaft current online monitoring system.

[0045] The obtained shaft voltage and shaft current signals are refreshed quickly and displayed through the display module, so that the change of the data wave table can be observed more directly, and potential problems can be found, as shown in the direct display result of the collected signals. Figure 2 The column chart of each frequency contained in the data is obtained quickly through the fast Fourier transform of the obtained shaft voltage and shaft current data, and the effective value of the voltage and current is obtained, thereby greatly improving the alarm accuracy. On the basis of the fast Fourier transform, the original data are preprocessed by applying the digital filtering principle to remove the noise interference in the signals and retain the effective signal components, thereby further improving the reliability of the monitoring and alarming.

[0046] In one specific embodiment, the signal collection module includes a sensor unit and a transmitter unit.

[0047] The sensor unit includes a voltage sensor and a shaft current transformer. The input and output terminals of the voltage sensor are connected with the excitation end brush and the steam end grounding point respectively, so as to detect the shaft voltage between the excitation end and the steam end and obtain an initial shaft voltage signal. The shaft current transformer is used to detect the size of the steam end shaft grounding current and obtain an initial shaft current signal.

[0048] The transmitter unit receives the initial shaft voltage signal and the initial shaft current signal, and converts them into standard 0-5VAC signals to obtain a shaft voltage signal and a shaft current signal.

[0049] Specifically, preventing the shaft current from being too large is to control the insulation of the shaft to ground well and not to form two-point grounding. If the insulation is good, the shaft current is small, otherwise, a larger shaft current will be generated to cause damage to the bearing and other hazards. When the increase of the shaft current is detected, the occurrence of the situation can be automatically judged, and an alarm is issued to prompt that the insulation condition needs to be repaired and maintained, thereby providing protection for the safe and reliable operation of the generator.

[0050] In one specific embodiment, the signal processing module includes a Fourier transform unit and a filtering unit.

[0051] The Fourier transform unit performs fast Fourier transform on the shaft voltage signal and the shaft current signal and sends them to the filtering unit. The filtering unit filters the signals after the Fourier transform to obtain a processed voltage signal and a processed current signal.

[0052] In one specific embodiment, the alarm module comprises a voltage threshold comparison unit, a first timing unit (axis voltage signal delay unit), a current threshold comparison unit, a second timing unit (axis current signal delay unit), and an alarm unit.

[0053] The voltage threshold comparison unit compares the processed voltage signal with the set threshold value in real time, and outputs a high level to the first timing unit when the set range is exceeded, and the first timing unit starts timing when receiving the high level, and issues a voltage alarm signal when the time length is greater than the set threshold value.

[0054] The current threshold comparison unit compares the processed current signal with the set threshold value in real time, and outputs a high level to the second timing unit when the set range is exceeded, and the second timing unit starts timing when receiving the high level, and issues a current alarm signal when the time length is greater than the set threshold value.

[0055] The alarm unit issues corresponding alarms according to the received voltage alarm signal and / or current alarm signal, and sends an alarm time signal to the storage module.

[0056] Specifically, the system can automatically trigger the alarm channel when it is determined that the current data effective value exceeds the set threshold value, and at the same time, the fault data of the alarm is saved synchronously. Through the fault playback function, the fault data is waveform played back, the data waveform form corresponding to the signal at the time of the fault is displayed, an observation and analysis window is provided for fault analysis, and through fast Fourier transform, the corresponding frequency spectrum is displayed, so that the staff can better analyze the possible cause of the fault.

[0057] In one specific embodiment, the voltage threshold comparison unit comprises a high voltage register, a low voltage register, a real-time voltage register, and a first comparator, and the first timing unit comprises a first timer and a second timer.

[0058] The high voltage register and the low voltage register store the threshold values of the high-axis voltage alarm signal and the low-axis voltage alarm signal, respectively, and the value stored in the real-time voltage register is updated in real time according to the voltage effective value of the processed voltage signal.

[0059] The first comparator compares the value stored in the real-time voltage register with the value stored in the high voltage register, and when the value stored in the real-time voltage register is greater, a high level is sent to the first timer, the first timer starts timing, and a high-axis voltage alarm signal is issued when the time length is greater than the set threshold value.

[0060] The first comparator compares the value stored in the real-time voltage register with the value stored in the low voltage register, and when the value stored in the real-time voltage register is smaller, a high level is sent to the second timer, the first timer starts timing, and a low-axis voltage alarm signal is issued when the time length is greater than the set threshold value.

[0061] In one specific embodiment, the current threshold comparison unit comprises a first high current register, a second high current register, a low current register, a real-time current register and a second comparator, and the second timing unit comprises a third timer, a fourth timer and a fifth timer;

[0062] The first high current register, the second high current register and the low current register store the threshold values of the 1st high-axis current signal, the 2nd high-axis current signal and the low-axis current alarm signal respectively, and the real-time current register stores a value which is updated in real time according to the current effective value of the processed current signal;

[0063] The second comparator compares the value stored in the real-time current register with the value stored in the first high current register, and when the value stored in the real-time current register is larger, a high level is sent to the third timer, the third timer starts timing, and when the timing duration is greater than a set threshold, the 1st high-axis current signal is sent;

[0064] The second comparator compares the value stored in the real-time current register with the value stored in the second high current register, and when the value stored in the real-time current register is larger, a high level is sent to the fourth timer, the fourth timer starts timing, and when the timing duration is greater than a set threshold, the 2nd high-axis current signal is sent;

[0065] The second comparator compares the value stored in the real-time current register with the value stored in the low current register, and when the value stored in the real-time current register is smaller, a high level is sent to the fifth timer, the fifth timer starts timing, and when the timing duration is greater than a set threshold, the low-axis current alarm signal is sent.

[0066] In one specific embodiment, the voltage alarm signal comprises a high-axis voltage alarm signal and a low-axis voltage alarm signal, and the current alarm signal comprises a 1st high-axis current signal, a 2nd high-axis current signal and a low-axis current signal;

[0067] When the voltage effective value of the processed voltage signal is greater than 10v and the timing duration is greater than 6s, the high-axis voltage alarm signal is sent; and when the voltage effective value of the processed voltage signal is less than 0.5v and the timing duration is greater than 60s, the low-axis voltage alarm signal is sent;

[0068] When the current effective value of the processed current signal is greater than 0.1A and the time length is greater than 15 minutes, a first high shaft current signal is sent; when the current effective value of the processed current signal is greater than 1A and the time length is greater than 3 seconds, a second high shaft current signal is sent; the low shaft current comparison alarm logic is a shaft current bypass system hardware test logic, which can be separately set with a threshold value and a time delay, when the current effective value of the processed current signal is less than 0.1A, the logic is entered, the signal is cut into the bypass, and other four groups of high shaft current 1, high shaft current 2, high shaft voltage and low shaft voltage alarms are shielded, the running cycle is 10 seconds, the alarm is delayed for 2 seconds, if the current effective value of the shaft is less than the low shaft current set threshold value 0.1A, the time length is greater than 2 seconds, and a low shaft current signal is sent. The above various alarm outputs can timely respond to various hazards in the running state of the generator, provide a prompt for the hazards existing in the generator during operation, and avoid causing great damage to the bearing bush and causing great economic losses.

[0069] In one specific embodiment, the alarm includes interface LED light / screen cabinet panel indicator light alarm and passive node alarm.

[0070] The various embodiments are described in a progressive manner in the specification, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0071] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An online monitoring system for shaft voltage and shaft current, characterized in that, include: Signal acquisition module, signal processing module, display module, alarm module, storage module; The signal acquisition module is electrically connected to the signal processing module, the display module, and the storage module respectively, and acquires the generator shaft voltage signal and shaft current signal, and sends them to the signal processing module, the storage module, and the display module respectively. The signal processing module is electrically connected to the display module, the alarm module, and the storage module respectively. It performs fast Fourier transform and filtering on the shaft voltage signal and the shaft current signal to obtain processed voltage signal and processed current signal, and sends them to the alarm module, the storage module, and the display module. The shaft voltage signal and the shaft current signal, as well as the processed voltage signal and the processed current signal, are all displayed through the display module and stored through the storage module; The alarm module is electrically connected to the storage module. It issues an alarm based on the processed voltage signal, the processed current signal, and a preset threshold, and sends the alarm time signal to the storage module.

2. The online monitoring system for shaft voltage and shaft current according to claim 1, characterized in that, The signal acquisition module includes a sensor unit and a transmitter unit; The sensor unit includes a voltage sensor and a shaft current transformer. The input and output terminals of the voltage sensor are connected to the excitation end brush and the steam end grounding point, respectively, to detect the shaft voltage between the excitation end and the steam end and obtain an initial shaft voltage signal. The shaft current transformer is used to detect the magnitude of the steam end shaft grounding current to obtain an initial shaft current signal. The transmitter unit receives the initial shaft voltage signal and the initial shaft current signal, and converts them into a standard 0-5VAC signal to obtain the shaft voltage signal and the shaft current signal.

3. The online monitoring system for shaft voltage and shaft current according to claim 1, characterized in that, The signal processing module includes a Fourier transform unit and a filtering unit; The Fourier transform unit performs a fast Fourier transform on the axis voltage signal and the axis current signal and sends them to the filtering unit; the filtering unit filters the Fourier transformed signals to obtain the processed voltage signal and the processed current signal.

4. The online monitoring system for shaft voltage and shaft current according to claim 1, characterized in that, The alarm module includes a voltage threshold comparison unit, a first timing unit, a current threshold comparison unit, a second timing unit, and an alarm unit; The voltage threshold comparison unit compares the processed voltage signal with the set threshold in real time. When the voltage exceeds the set range, it outputs a high level to the first timing unit. The first timing unit starts timing upon receiving the high level. When the voltage exceeds the set threshold, it issues a voltage alarm signal. The current threshold comparison unit compares the processed current signal with the set threshold in real time. When the current exceeds the set range, it outputs a high level to the second timing unit. The second timing unit receives the high level and starts timing. When the current exceeds the set threshold, it issues a current alarm signal. The alarm unit issues a corresponding alarm based on the received voltage alarm signal and / or current alarm signal, and sends the alarm time signal to the storage module.

5. The online monitoring system for shaft voltage and shaft current according to claim 4, characterized in that, The voltage threshold comparison unit includes a high voltage register, a low voltage register, a real-time voltage register, and a first comparator; the first timing unit includes a first timer and a second timer. The high voltage register and low voltage register store the threshold values ​​of the high axis voltage alarm signal and the low axis voltage alarm signal, respectively. The value stored in the real-time voltage register is updated in real time according to the effective voltage value of the processed voltage signal. The first comparator compares the value stored in the real-time voltage register with the value stored in the high voltage register. When the value stored in the real-time voltage register is larger, a high level is sent to the first timer, and the first timer starts counting. If the duration exceeds a set threshold, a high-axis voltage alarm signal is issued. The first comparator compares the value stored in the real-time voltage register with the value stored in the low voltage register. When the value stored in the real-time voltage register is small, it sends a high level to the second timer, and the first timer starts counting. If the duration exceeds a set threshold, it sends a low-axis voltage alarm signal.

6. The online monitoring system for shaft voltage and shaft current according to claim 4, characterized in that, The current threshold comparison unit includes a first high current register, a second high current register, a low current register, a real-time current register, and a second comparator; the second timing unit includes a third timer, a fourth timer, and a fifth timer. The first high current register, the second high current register, and the low current register respectively store the threshold values ​​of the first-level high-axis current signal, the second-level high-axis current signal, and the low-axis current alarm signal. The value stored in the real-time current register is updated in real time according to the effective value of the processed current signal. The second comparator compares the value stored in the real-time current register with the value stored in the first high current register. When the value stored in the real-time current register is larger, a high level is sent to the third timer, and the third timer starts timing. If the duration is greater than a set threshold, the first-level high-axis current signal is sent. The second comparator compares the value stored in the real-time current register with the value stored in the second high current register. When the value stored in the real-time current register is larger, a high level is sent to the fourth timer, and the fourth timer starts counting. If the duration is greater than a set threshold, the second-level high-axis current signal is sent. The second comparator compares the value stored in the real-time current register with the value stored in the low current register. When the value stored in the real-time current register is small, a high level is sent to the fifth timer, and the fifth timer starts counting. If the duration exceeds a set threshold, the low-axis current alarm signal is issued.

7. The online monitoring system for shaft voltage and shaft current according to claim 4, characterized in that, The voltage alarm signal includes a high-axis voltage alarm signal and a low-axis voltage alarm signal, and the current alarm signal includes a level 1 high-axis current signal, a level 2 high-axis current signal, and a low-axis current signal. If the effective value of the processed voltage signal is greater than 10V and the timing duration is greater than 6 seconds, a high-axis voltage alarm signal is issued; if the effective value of the processed voltage signal is less than 0.5V and the timing duration is greater than 6 seconds, a low-axis voltage alarm signal is issued. If the effective value of the processed current signal is greater than 0.1A and the timing duration is greater than 15 minutes, then the Level 1 high-axis current signal is emitted; if the effective value of the processed current signal is greater than 1A and the timing duration is greater than 3 seconds, then the Level 2 high-axis current signal is emitted; if the effective value of the processed current signal is less than 0.1A and the timing duration is greater than 2 seconds, then the low-axis current signal is emitted.

8. The online monitoring system for shaft voltage and shaft current according to claim 4, characterized in that, The alarms include light alarms from interface LED lights / cabinet panel indicator lights and passive node alarms.

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