On-site calibration device and method for online status monitoring system of hydro-generator set

Abstract

The invention relates to an on-site verification device for an online state monitoring system of a hydro-turbine generator set, comprising a signal generating unit, a signal modulating unit and a signal converting unit, wherein the signal generating unit comprises a monolithic integrated function generator and a wide-band direct current power amplifier circuit, the monolithic integrated function generator is connected to the wide-band direct current power amplifier circuit, the wide-band direct current power amplifier circuit is connected to the signal modulating unit, the signal modulating unit is connected to the signal converting unit, and the signal converting unit outputs a voltage signal and a current signal. Without disassembling the online state monitoring system of the unit, the invention simulates the signal characteristics of various types of sensors through an on-site verification device, outputs modulated voltage / current signals, and adopts standard steps and methods to verify on-site the accuracy of signal acquisition of each channel of the core equipment of the online state monitoring system, as well as the amplitude-frequency analysis function and alarm logic of the software.

Description

Technical Field

[0001] The invention relates to an on-site calibration device and method for an online state monitoring system of a hydro-generator set, belonging to the technical field of online state monitoring of hydro-generator sets. Background Art

[0002] The online status monitoring system of the hydro-turbine generator set is a monitoring device that monitors the operating status of each part of the hydro-turbine generator set in real time. Its main monitoring data are the swing, vibration, and pressure pulsation of the unit, including some operating parameters. Some operating parameters are provided by other monitoring equipment, mainly 4-20mA current signals, as reference values ​​for operation analysis. As a monitoring device for the hydropower station unit, the system is generally installed in the panel cabinet of the generator layer. At present, the calibration of the system only calibrates the sensor. Due to the difficulty of disassembly and transportation, the on-site calibration work has not yet covered the core hardware equipment of the system-data collector. Secondly, the amplitude-frequency analysis of the system software is the most important means to judge the operating condition of the unit. The standard signal used by the manufacturer for factory inspection is only a constant current signal and a single-frequency voltage signal, which has a large deviation from the stability signal of the actual hydro-turbine generator set, and the calibration work of the software amplitude-frequency analysis function is lacking. In summary, due to the lack of suitable on-site calibration devices and methods, when the unit operating status is abnormal, it is impossible to quickly judge whether the data provided by the online status monitoring system is accurate and reliable, which affects the analysis and judgment of the unit failure by the power plant operators. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the present invention provides a device and method for performing on-site calibration without disassembling an online status monitoring system of a unit.

[0004] In order to achieve the above-mentioned purpose, the technical solution proposed in the present invention is: a field verification device for an online status monitoring system of a hydro-turbine generator set, comprising a signal generating unit, a signal modulation unit and a signal conversion unit, wherein the signal generating unit comprises a monolithic integrated function generator and a wide-band DC power amplifier circuit, wherein the monolithic integrated function generator is connected to the wide-band DC power amplifier circuit, wherein the wide-band DC power amplifier circuit is connected to the signal modulation unit, wherein the signal modulation unit is connected to the signal conversion unit, and wherein the signal conversion unit outputs a voltage signal and a current signal.

[0005] A further design of the above technical solution is as follows: the signal generating unit further includes a selection gate, the wide-band DC power amplifier circuit is connected to the selection gate, and the selection gate is connected to a three-way adder.

[0006] The selection gate outputs a signal without a waveform and a waveform signal respectively, the signal without a waveform is output as a verification signal, and the waveform signal is output to a signal modulation unit.

[0007] The signal modulation unit includes a three-way adder, and the selection gate is connected to the three-way adder.

[0008] The three-way adder is provided with three input terminals, and the three input terminals are respectively connected to a signal generating unit.

[0009] The signal conversion unit comprises a signal converter, and the output end of the three-way adder is connected to the signal converter.

[0010] The signal modulation unit further includes a voltage-stabilized power supply, which is connected to a three-way adder; the signal generation unit further includes a power supply module, which is connected to a broadband DC power amplifier circuit.

[0011] The single-chip integrated function generator adopts a MAX038 chip. The output frequency range of the single-chip integrated function generator is between 0.1 and 20 MHz, and the peak value of the output waveform is ±2V.

[0012] A method for on-site verification of an online status monitoring system of a hydro-generator set comprises the following steps:

[0013] Step 1: Remove the sensor input signal line of the online status monitoring system of the hydro-generator set, connect the output signal of the field verification device to the monitoring system and use it as the input signal of the monitoring system;

[0014] Step 2: Use the on-site calibration device to output a sine wave signal with a bias voltage V0. The amplitude voltage of the signal is V p-p , record the deviation between the collected voltage value and the input voltage value of the monitoring system, and verify the amplitude analysis function of the monitoring system;

[0015] Use the on-site calibration device to modulate different frequencies and different V p-p The synthesized signal is recorded, and the frequency value and amplitude of each component after the system spectrum analysis are recorded, and compared with the input value to verify the spectrum analysis function of the system;

[0016] Use the on-site verification device to output square wave signals and gradually increase the duty cycle to simulate the gear waveform of the unit and verify the speed test accuracy of the monitoring system;

[0017] Step 3: Use the on-site calibration device to output the current value I, record the deviation between the system's collected current value and the input current value, and calibrate the test accuracy of the current channel;

[0018] The on-site calibration device is used to output a sine wave signal with a bias current I0, and the amplitude of the signal is I p-p , record the deviation between the collected current value and the input current value of the monitoring system, and verify the amplitude analysis function of the monitoring system;

[0019] Use the on-site calibration device to modulate different frequencies and different Ip-p The synthesized signal is recorded to record the frequency and amplitude of each component after the spectrum analysis of the monitoring system, and compared with the input value to verify the spectrum analysis function of the system;

[0020] Step 4: Repeat steps 2 and 3, and gradually increase V p-p and I P-P value, until the amplitude response reaches and exceeds the alarm value set by the system, record the deviation between the input value and the set value when the alarm occurs, and verify the alarm function of the monitoring system;

[0021] Step 5: Remove the connection between the on-site verification device and the monitoring system.

[0022] A further design of the above method is: the amplitude voltage V of the sine wave signal output in step 2 is p-p No less than 3 groups;

[0023] In step 3, the output current value I is between 4 and 20 mA, and there are no less than 8 groups; the amplitude of the output sine wave signal I p-p No less than 3 groups.

[0024] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0025] The present invention designs a field verification device suitable for the characteristics of the online status monitoring system of the hydro-turbine generator set without disassembling the online status monitoring system of the unit. The device can simulate the signal characteristics of various types of sensors, output modulated voltage / current signals, and use standard steps and methods to verify the accuracy of signal acquisition of each channel of the core equipment of the online status monitoring system, as well as the amplitude-frequency analysis function and alarm logic of the software, thereby solving the problem of field verification of the online status monitoring system of the hydro-turbine generator set.

[0026] The single-chip integrated function generator used in the signal generating unit of the device of the present invention adopts the MAX038 single-chip microcomputer, which focuses on the accuracy of the low-frequency output signal of 0.5Hz to 50Hz, which is consistent with the characteristics of the hydro-generator set that mainly vibrates at a low frequency. The signal modulation unit can output the vector sum signal of three signals at most, simulating the multi-component characteristics of the vibration of the hydro-generator set. The input and output signals of the signal modulation unit maintain the same accuracy and frequency. The signal conversion unit converts the modulated voltage signal into a current signal to verify the current channel of the online status monitoring system.

[0027] The device of the present invention has a simple structure and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the field verification device of the present invention;

[0029] Figure 2This is a circuit diagram of a signal modulation unit of the present invention;

[0030] Figure 3 It is a flow chart of the on-site verification method of the present invention. DETAILED DESCRIPTION

[0031] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0032] like Figure 1 As shown, the on-site verification device of the online monitoring system of the hydro-generator set of this embodiment includes a signal generating unit, a signal modulation unit and a signal conversion unit which are connected in sequence.

[0033] In this embodiment, the signal generating unit adopts a mature function signal generator. In order to adapt to the frequency characteristics of the hydro-generator set, the low-frequency characteristics of the signal are particularly emphasized. In this embodiment, the core of the unit adopts a monolithic integrated function generator, and a MAX038 chip is selected. The chip provides a 2.5V reference voltage and an external resistor and capacitor. The output frequency range can be controlled between 0.1 and 20MHz. By setting the sine wave or square wave output, the peak-to-peak value of all waveform outputs is ±2V. In this embodiment, the signal generating unit also includes a wide-band DC power amplifier circuit and a selection gate. The signal output by the monolithic integrated function generator passes through the wide-band DC power amplifier circuit, and after calculation, passes through the selection gate. The waveform-free signal output by the selection gate is directly output as a verification signal, and the waveform signal is output to the signal modulation unit.

[0034] like Figure 2 As shown in the figure, the signal modulation unit is mainly composed of an op amp and an excitation power supply, and is essentially an adder. The adder can receive the V p-p , V0 signal, after the operational amplifier unit, is output in the same phase or inverted phase. The signal amplification factor is determined by R, and the output voltage V out is the vector sum of the input voltages. The output of the signal modulation unit can be directly used as a calibration signal for the voltage channel. When calibrating the current channel, the output of the signal modulation unit enters the signal conversion unit as an input signal of the signal conversion unit.

[0035] Since the signal generation unit can only output voltage signals, the current channel of the online status monitoring system requires I p-p , I0 signal, so this embodiment sets a signal conversion unit to convert V p-p 、V0 converted to I p-p, I0, the signal conversion unit includes a signal converter, which is mainly composed of an adjustable potentiometer and a power supply. The core is the adjustable potentiometer, which converts the voltage signal into a current signal by changing the impedance of the potentiometer while satisfying power consumption and signal distortion. The output current signal is used as a calibration signal for the current channel.

[0036] like Figure 3 The on-site verification implementation plan is as follows:

[0037] (1) Preparation of calibration equipment. Check the power supply of the on-site calibration device, manually input the signal, use a high-precision oscilloscope to collect the output signal, and compare it with the set signal to ensure the accuracy of the output signal of the on-site calibration device; re-adjust the channel parameters of the online status monitoring system and set the channel rate to be consistent with the input signal for easy recording and analysis.

[0038] (2) Wiring. Remove the sensor input signal line of the online status monitoring system and use the output signal of the field calibration device as the input signal of the system. In this step, pay attention to the difference between voltage and current wiring.

[0039] (3) Voltage channel verification

[0040] 3.1 Use the on-site calibration device to output a sine wave signal with a bias voltage. The bias voltage V0 and amplitude voltage V p-p It can be determined according to the type of sensor selected by the system. For example, if an eddy current displacement sensor is used, the bias voltage V0 is generally selected as -10V (middle value), and the amplitude voltage V p-p No less than 3 groups, record the deviation between the system's collected voltage value and the input voltage value, and verify the system's amplitude analysis function.

[0041] 3.2 Using different frequencies and different V modulated by the field calibration device p-p The frequency components of the synthetic signal should at least include the combination of frequency conversion, low frequency, and frequency doubling. The V p-p The voltage range should include the main application range of the monitoring system. The frequency value and amplitude of each component after the system spectrum analysis should be recorded and compared with the input value to verify the spectrum analysis function of the system.

[0042] 3.3 Check the voltage channel that mainly collects vibration signals. This step is basically the same as steps 3.1 and 3.2, except that the sine wave voltage signal does not need to be biased.

[0043] 3.4 Verify the voltage channel for collecting speed. Use the square wave signal output by the on-site verification device to gradually increase the duty cycle, simulate the gear waveform of the unit, and verify the speed test accuracy of the system.

[0044] (4) Verify the current channel for collecting pressure pulsation and operating parameters.

[0045] 4.1 Use the on-site calibration device to output the current value I0, the current value I0 is selected between 4~20mA, no less than 8 groups, record the deviation between the system's collected current value and the input current value, and calibrate the test accuracy of the current channel.

[0046] 4.2 Use the on-site calibration device to output a sine wave signal with bias current. The bias current I0 and amplitude I p-p It can be determined according to the type of sensor selected by the system. p-p No less than 3 groups, record the deviation between the system's collected current value and the input current value, and verify the system's amplitude analysis function.

[0047] 4.3 Using different frequencies and different I modulated by the field calibration device p-p The frequency components of the synthetic signal should at least include the combination of the conversion frequency, low frequency, and frequency doubling. p-p The voltage range should include the main application range of the system. Record the frequency value and amplitude of each component after the system spectrum analysis, compare them with the input value, and verify the spectrum analysis function of the system.

[0048] (5) Repeat steps (3) and (4) and gradually increase V p-p and I P-P value until the amplitude response reaches and exceeds the alarm value set by the system, record the deviation between the input value and the set value when the alarm occurs, and verify the alarm function of the system.

[0049] (6) Record data, generate reports, and then remove the connection between the field calibration device and the monitoring system.

[0050] The method of this embodiment regards the online state monitoring system as an organic whole. The verification content includes signal acquisition of the hardware part and functional analysis of the software part. And for the signal channels for collecting different types of stability parameters, a verification method suitable for them is proposed. The method of this embodiment incorporates speed measurement into the verification content and designs a verification method suitable for it.

[0051] The synthetic signal used in the method of this embodiment is set according to the frequency spectrum characteristics of the multi-component stability parameters of the hydro-generator set. The synthetic signal used can simulate the stability parameters of the set and verify the analysis function of the online status monitoring system software part for complex signals, especially the frequency spectrum analysis function.

[0052] Conventional current channel calibration only performs accuracy calibration of the average value, which has a major drawback for channels that test pressure pulsation. This method adds calibration of the amplitude and spectrum analysis functions based on the accuracy calibration of the average value test.

[0053] The technical solutions of the present invention are not limited to the above-mentioned embodiments, and any technical solutions obtained by equivalent replacement methods fall within the scope of protection required by the present invention.

Claims

1. A field calibration device for an online status monitoring system of a hydro-generator set, characterized in that: It includes a signal generating unit, a signal modulating unit and a signal converting unit, wherein the signal generating unit includes a monolithic integrated function generator and a wide-band DC power amplifier circuit, the monolithic integrated function generator is connected to the wide-band DC power amplifier circuit, the wide-band DC power amplifier circuit is connected to the signal modulating unit, the signal modulating unit is connected to the signal converting unit, and the signal converting unit outputs a voltage signal and a current signal; The on-site verification method of the online status monitoring system of the hydro-generator set comprises the following steps: Step 1: Remove the sensor input signal line of the online status monitoring system of the hydro-generator set, connect the output signal of the field verification device to the monitoring system and use it as the input signal of the monitoring system; Step 2: Use the on-site calibration device to output a sine wave signal with a bias voltage V0. The amplitude voltage of the signal is V p-p , record the deviation between the collected voltage value and the input voltage value of the monitoring system, and verify the amplitude analysis function of the monitoring system; Use the on-site calibration device to modulate different frequencies and different V p-p The synthetic signal is recorded, and the frequency value and amplitude of each component after the monitoring system spectrum analysis are compared with the input value to verify the spectrum analysis function of the monitoring system; Use the on-site verification device to output square wave signals and gradually increase the duty cycle to simulate the gear waveform of the unit and verify the speed test accuracy of the monitoring system; Step 3: Use the on-site calibration device to output the current value I, record the deviation between the system's collected current value and the input current value, and calibrate the test accuracy of the current channel; The on-site calibration device is used to output a sine wave signal with a bias current I0. The amplitude of the signal is I p-p , record the deviation between the collected current value and the input current value of the monitoring system, and verify the amplitude analysis function of the monitoring system; Use the on-site calibration device to modulate different frequencies and different I p-p The synthesized signal is recorded, and the frequency value and amplitude of each component after the system spectrum analysis are recorded, and compared with the input value to verify the spectrum analysis function of the monitoring system; Step 4: Repeat steps 2 and 3, and gradually increase V p-p and I P-P value, until the amplitude response reaches and exceeds the alarm value set by the system, record the deviation between the input value and the set value when the alarm occurs, and verify the alarm function of the monitoring system; Step 5: Remove the connection between the on-site verification device and the monitoring system.

2. According to claim 1, the on-site verification device for the online status monitoring system of a hydro-generator set is characterized by: The signal generating unit further comprises a selection gate, the wide-band direct current power amplifier circuit is connected to the selection gate, and the selection gate is connected to a three-way adder.

3. According to claim 2, the on-site verification device for the online status monitoring system of a hydro-generator set is characterized in that: The selection gate outputs a signal without a waveform and a waveform signal respectively, the signal without a waveform is output as a verification signal, and the waveform signal is output to a signal modulation unit.

4. According to claim 3, the on-site verification device for the online status monitoring system of a hydro-generator set is characterized in that: The signal modulation unit includes a three-way adder, and the selection gate is connected to the three-way adder.

5. According to claim 4, the on-site verification device for the online status monitoring system of a hydro-generator set is characterized in that: The three-way adder is provided with three input terminals, and the three input terminals are respectively connected to a signal generating unit.

6. The on-site verification device for the online status monitoring system of a hydro-generator set according to claim 5 is characterized in that: The signal conversion unit comprises a signal converter, and the output end of the three-way adder is connected to the signal converter.

7. The on-site verification device for the online status monitoring system of a hydro-generator set according to claim 4 is characterized by: The signal modulation unit further includes a voltage-stabilized power supply, which is connected to a three-way adder; the signal generation unit further includes a power supply module, which is connected to a broadband DC power amplifier circuit.

8. According to claim 1, the on-site verification device for the online status monitoring system of a hydro-generator set is characterized by: The single-chip integrated function generator adopts a MAX038 chip; the output frequency range of the single-chip integrated function generator is between 0.1 and 20 MHz, and the peak value of the output waveform is ±2V.

9. The on-site verification device for the online status monitoring system of a hydro-generator set according to claim 8 is characterized in that: The amplitude voltage V of the sine wave signal output in step 2 p-p No less than 3 groups; In step 3, the output current value I is between 4 and 20 mA and is not less than 8 groups; the amplitude Ip-p of the output sinusoidal wave signal is not less than 3 groups.

Images