阅读说明：本技术 一种水轮发电机组在线状态监测系统现场校验装置和方法 (On-site calibration device and method for online state monitoring system of hydroelectric generating set ) 是由 蒋致乐 郑凯 薛晨 易瑞吉 刘旻 于 2020-12-29 设计创作，主要内容包括：本发明涉及一种水轮发电机组在线状态监测系统现场校验装置,包括信号发生单元、信号调制单元和信号转换单元,所述信号发生单元包括单片集成函数发生器和宽频带直流功放电路,所述单片集成函数发生器与宽频带直流功放电路连接,宽频带直流功放电路与信号调制单元连接,所述信号调制单元与信号转换单元连接,所述信号转换单元输出电压信号和电流信号；本发明在不拆卸机组在线状态监测系统的前提下,通过现场校验装置,模拟各型传感器的信号特性,输出调制过的电压/电流信号,采用标准的步骤和方法,现场校验在线状态监测系统的核心设备各通道信号采集的准确性,以及软件的幅频分析功能和报警逻辑。(The invention relates to a field calibration device of an online state monitoring system of a water turbine generator set, which comprises a signal generating unit, a signal modulation unit and a signal conversion unit, wherein the signal generating unit comprises a single-chip integration function generator and a broadband direct current power amplifier circuit; the invention simulates the signal characteristics of various sensors and outputs modulated voltage/current signals through a field calibration device on the premise of not disassembling the unit online state monitoring system, and adopts standard steps and methods to carry out field calibration on the accuracy of signal acquisition of each channel of core equipment of the online state monitoring system, and the amplitude-frequency analysis function and the alarm logic of software.)

1. The utility model provides a hydroelectric set on-line condition monitoring system on-spot calibration equipment which characterized in that: the broadband direct-current power amplifier comprises a signal generating unit, a signal modulating unit and a signal converting unit, wherein the signal generating unit comprises a single-chip integration function generator and a broadband direct-current power amplifier circuit, the single-chip integration function generator is connected with the broadband direct-current power amplifier circuit, the broadband direct-current power amplifier circuit is connected with the signal modulating unit, the signal modulating unit is connected with the signal converting unit, and the signal converting unit outputs a voltage signal and a current signal.

2. The field calibration device of the online state monitoring system of the hydroelectric generating set according to claim 1, characterized in that: the signal generation unit further comprises a selection gate, the broadband direct current power amplifier circuit is connected with the selection gate, and the selection gate is connected with the three-way adder.

3. The field calibration device of the online state monitoring system of the hydroelectric generating set according to claim 1, characterized in that: the selection gate respectively outputs a non-waveform signal and a waveform signal, the non-waveform signal is output as a verification signal, and the waveform signal is output to the signal modulation unit.

4. The field calibration device of the online state monitoring system of the hydroelectric generating set according to claim 3, characterized in that: the signal modulation unit comprises a three-way adder, and the selection gate is connected with the three-way adder.

5. The field calibration device of the online state monitoring system of the hydroelectric generating set according to claim 4, characterized in that: the three-way adder is provided with three input ends, and the three input ends are respectively connected with a signal generating unit.

6. The field calibration device of the online state monitoring system of the hydroelectric generating set according to claim 5, characterized in that: the signal conversion unit comprises a signal converter, and the output end of the three-way adder is connected with the signal converter.

7. The field calibration device of the online state monitoring system of the hydroelectric generating set according to claim 4, characterized in that: the signal modulation unit further comprises a stabilized voltage power supply which is connected with the three-way adder; the signal generation unit further comprises a power module, and the power module is connected with the broadband direct current power amplifier circuit.

8. The field calibration device of the online state monitoring system of the hydroelectric generating set according to claim 1, characterized in that: the monolithic integration function generator adopts an MAX038 chip; the output frequency range of the monolithic integration function generator is between 0.1 and 20MHz, and the peak value of an output waveform is +/-2V.

9. The field calibration method for the online state monitoring system of the hydroelectric generating set is characterized by comprising the following steps of:

firstly, removing a sensor input signal line of an online state monitoring system of the water-turbine generator set, connecting an output signal of a field calibration device with the monitoring system and using the output signal as an input signal of the monitoring system;

step two, outputting the voltage V with the offset value by adopting a field calibration device₀Of a sine wave signal of amplitude voltage V_p-pRecording the deviation between the acquired voltage value and the input voltage value of the monitoring system, and verifying the amplitude analysis function of the monitoring system;

modulating different frequencies and different V's with an in-situ calibration device_p-pThe frequency value and the amplitude value of each component after the frequency spectrum analysis of the monitoring system are recorded and compared with the input value, and the frequency spectrum analysis function of the monitoring system is verified;

outputting a square wave signal by adopting a field checking device, gradually increasing the duty ratio, simulating a fluted disc waveform of a unit, and checking the rotating speed testing precision of a monitoring system;

outputting a current value I by adopting a field checking device, recording the deviation of the acquired current value and the input current value of the system, and checking the test precision of the current channel;

outputting current I with offset value by using field checking device₀Of a sine wave signal of amplitude I_p-pRecording the deviation between the acquired current value and the input current value of the monitoring system, and checking the amplitude analysis function of the monitoring system;

modulating different frequencies and different I by using on-site calibration device_p-pThe frequency value and the amplitude value of each component after the system frequency spectrum analysis are recorded and compared with the input value, and the frequency spectrum analysis function of the monitoring system is verified;

step four, repeating the step two and the step three, and gradually increasing V_p-pAnd I_P-PUntil the amplitude response reaches or exceeds the alarm value set by the system, recording the deviation between the input value and the set value during alarming, and verifying the alarm function of the monitoring system;

and fifthly, removing the connection between the on-site calibration device and the monitoring system.

10. The field calibration method for the online state monitoring system of the hydroelectric generating set according to claim 9, wherein in the second step, the amplitude voltage V of the sine wave signal is output_p-pNot less than 3 groups;

in the third step, the output current value I is between 4 and 20mA, and is not less than 8 groups; the amplitude Ip-p of the output sine wave signal is not less than 3 groups.

Technical Field

The invention relates to a field calibration device and method for a hydroelectric generating set online state monitoring system, and belongs to the technical field of hydroelectric generating set online state monitoring.

Background

The on-line state monitoring system for the water-turbine generator set is a monitoring device for monitoring the running state of each part of the water-turbine generator set in real time on line. The main monitoring data of the intelligent control system are the swing degree, vibration and pressure pulsation of the unit, and comprise part of working condition parameters, wherein the part of working condition parameters are provided by other monitoring equipment, and are mainly current signals of 4-20 mA which are used as reference values for operation analysis. The system is used as monitoring equipment of a hydropower station unit and is generally arranged in a screen cabinet of a generator layer. At present, the system is only checked, the sensor is only checked, due to the difficulty in disassembly and transportation, the core hardware device-data acquisition device of the system is not covered by field checking work, secondly, amplitude-frequency analysis of system software is the most important means for judging the working condition of the unit, standard signals adopted by factory delivery inspection are only constant current signals and single-frequency voltage signals, the deviation of the standard signals and the stability signals of an actual water-turbine generator set is large, and the checking work of the software amplitude-frequency analysis function is deficient. In summary, due to the lack of a suitable on-site calibration device and method, when the unit running state is abnormal, it cannot be quickly determined whether the data provided by the on-line state monitoring system is accurate and reliable, which affects the analysis and determination of the power plant operator on the unit fault.

Disclosure of Invention

The invention provides a device and a method for on-site verification on the premise of not disassembling an online state monitoring system of a unit, aiming at solving the problems in the prior art.

In order to achieve the purpose, the technical scheme provided by the invention is as follows: the utility model provides a hydroelectric set on-line status monitoring system on-site calibration equipment, includes signal generation unit, signal modulation unit and signal conversion unit, the signal generation unit includes monolithic integration function generator and broadband direct current power amplifier circuit, monolithic integration function generator is connected with broadband direct current power amplifier circuit, and broadband direct current power amplifier circuit is connected with signal modulation unit, signal modulation unit and signal conversion unit are connected, signal conversion unit output voltage signal and current signal.

The technical scheme is further designed as follows: the signal generation unit further comprises a selection gate, the broadband direct current power amplifier circuit is connected with the selection gate, and the selection gate is connected with the three-way adder.

The selection gate respectively outputs a non-waveform signal and a waveform signal, the non-waveform signal is output as a verification signal, and the waveform signal is output to the signal modulation unit.

The signal modulation unit comprises a three-way adder, and the selection gate is connected with the three-way adder.

The three-way adder is provided with three input ends, and the three input ends are respectively connected with a signal generating unit.

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

The signal modulation unit further comprises a stabilized voltage power supply which is connected with the three-way adder; the signal generation unit further comprises a power module, and the power module is connected with the broadband direct current power amplifier circuit.

The monolithic integration function generator adopts a MAX038 type chip. The output frequency range of the monolithic integration function generator is between 0.1 and 20MHz, and the peak value of an output waveform is +/-2V.

A field calibration method for a hydroelectric generating set on-line state monitoring system comprises the following steps:

firstly, removing a sensor input signal line of an online state monitoring system of the water-turbine generator set, connecting an output signal of a field calibration device with the monitoring system and using the output signal as an input signal of the monitoring system;

step two, outputting the voltage V with the offset value by adopting a field calibration device₀Of a sine wave signal of amplitude voltage V_p-pRecording the deviation between the collected voltage value and the input voltage value of the monitoring system, and checking the monitoring systemThe amplitude analysis function of (1);

modulating different frequencies and different V's with an in-situ calibration device_p-pRecording the frequency value and the amplitude value of each component after the system frequency spectrum analysis, comparing the frequency value and the amplitude value with the input value, and checking the frequency spectrum analysis function of the system;

outputting a square wave signal by adopting a field checking device, gradually increasing the duty ratio, simulating a fluted disc waveform of a unit, and checking the rotating speed testing precision of a monitoring system;

outputting a current value I by adopting a field checking device, recording the deviation of the acquired current value and the input current value of the system, and checking the test precision of the current channel;

outputting current I with offset value by using field checking device₀Of a sine wave signal of amplitude I_p-pRecording the deviation between the acquired current value and the input current value of the monitoring system, and checking the amplitude analysis function of the monitoring system;

modulating different frequencies and different I by using on-site calibration device_p-pThe frequency value and the amplitude value of each component after the frequency spectrum analysis of the monitoring system are recorded and compared with the input value, and the frequency spectrum analysis function of the system is verified;

step four, repeating the step two and the step three, and gradually increasing V_p-pAnd I_P-PUntil the amplitude response reaches or exceeds the alarm value set by the system, recording the deviation between the input value and the set value during alarming, and verifying the alarm function of the monitoring system;

and fifthly, removing the connection between the on-site calibration device and the monitoring system.

The method is further designed as follows: outputting the amplitude voltage V of the sine wave signal in the second step_p-pNot less than 3 groups;

in the third step, the output current value I is between 4 and 20mA, and is not less than 8 groups; amplitude I of the output sine wave signal_p-pNot less than 3 groups.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

on the premise of not disassembling the on-line state monitoring system of the unit, the invention designs a set of on-site calibration device suitable for the characteristics of the on-line state monitoring system of the water-turbine generator set, which can simulate the signal characteristics of various sensors and output modulated voltage/current signals.

The monolithic integration function generator adopted in the signal generating unit in the device adopts an MAX038 type monolithic processor, pays attention to the accuracy of meeting the low-frequency output signal of 0.5 Hz-50 Hz, and is consistent with the characteristic of mainly low-frequency vibration of a water-turbine generator set. The signal modulation unit can output the vector sum signal of three paths of signals at most and simulate the multi-component characteristic of the vibration of the water-turbine generator set. The input and output signals of the signal modulation unit keep consistent in precision and frequency. And the signal conversion unit converts the modulated voltage signal into a current signal and verifies a current channel of the online state monitoring system.

The device has simple structure and convenient operation.

Drawings

FIG. 1 is a schematic diagram of the field verification device of the present invention;

FIG. 2 is a circuit diagram of a signal modulation unit according to the present invention;

FIG. 3 is a flow chart of a field verification method of the present invention.

Detailed Description

The invention is described in detail below with reference to the figures and the specific embodiments.

Examples

As shown in fig. 1, the field calibration device of the online monitoring system of the water turbine generator set in the embodiment includes a signal generating unit, a signal modulating unit and a signal converting unit, which are connected in sequence.

In this embodiment, the signal generating unit adopts a mature function signal generator, and in order to adapt to the frequency characteristics of the water-turbine generator set, especially, the low-frequency characteristics of the signal are emphasized, the core of the signal generating unit in this embodiment adopts a monolithic integration function generator, and a MAX038 type chip is selected, a 2.5V reference voltage and an external resistor and a capacitor are provided inside the chip, the output frequency range can be controlled between 0.1-20 MHz, and by setting sine wave or square wave output, the peak-to-peak value output by all waveforms is ± 2V. In this embodiment, the signal generating unit further includes a wideband dc power amplifier circuit and a selection gate, and after the signal output by the monolithic integration function generator passes through the wideband dc power amplifier circuit and is operated, the signal without waveform output by the selection gate is directly output as a check signal through the selection gate, and the signal with waveform is output to the signal modulating unit.

As shown in fig. 2, the signal modulation unit mainly comprises an operational amplifier and an excitation power supply, and is substantially an adder. The adder can receive V transmitted by the 3-path signal generating unit_p-p、V₀The signal is output in phase or in reverse phase through an operational amplifier unit, the amplification factor of the signal is determined by R, and the output voltage V_outIs the vector sum of the input voltages. The output of the signal modulation unit can be directly used as a verification signal of a voltage channel, and when the current channel is verified, the output of the signal modulation unit is used as an input signal of the signal conversion unit and enters the signal conversion unit.

Because the signal generating unit can only output voltage signals, and the current channel of the on-line state monitoring system needs I_p-p、I₀Signals, so this embodiment is provided with a signal conversion unit to convert V_p-p、V₀Conversion to I_p-p、I₀The signal conversion unit comprises a signal converter and mainly consists of an adjustable potentiometer and a power supply. The core of the device is an adjustable potentiometer, a voltage signal is converted into a current signal by changing the impedance of the potentiometer under the conditions of meeting the requirements of power consumption and no signal distortion, and the output current signal is used as a check signal of a current channel.

As shown in fig. 3, the field verification implementation is as follows:

(1) the verification device is prepared. Checking a power supply of the on-site calibration device, manually inputting a signal, collecting an output signal by using a high-precision oscilloscope, and comparing the output signal with a set signal to ensure the precision of the output signal of the on-site calibration device; and re-setting the channel parameters of the online state monitoring system, and determining the channel rate to be consistent with the input signal, so that the recording and analysis are convenient.

(2) And (6) wiring. The sensor input signal line of the online condition monitoring system is removed, the output signal of the field verification device is used as the input signal of the system, and the step pays attention to the difference of voltage and current wiring.

(3) Voltage channel verification

3.1 outputting sine wave signal with bias voltage by using on-site checking device₀And amplitude voltage V_p-pDepending on the type of sensor chosen for the system, e.g. eddy current displacement sensors, bias voltage V₀Is generally selected to be-10V (median), amplitude voltage V_p-pAnd no less than 3 groups of the voltage values are recorded, the deviation between the collected voltage value and the input voltage value of the system is recorded, and the amplitude analysis function of the system is verified.

3.2 different frequencies and different V modulated by the field-check device_p-pThe frequency component of the synthesized signal should at least comprise a combination of frequency conversion, low frequency and frequency multiplication, and the V of each component of the synthesized signal_p-pThe voltage range should include the main application interval of the monitoring system, the frequency value and the amplitude of each component after the system frequency spectrum analysis are recorded, and the frequency spectrum analysis function of the system is verified by comparing the frequency value and the amplitude with the input value.

3.3 verifying the voltage channel mainly collecting the vibration signal. This step is substantially identical to steps 3.1 and 3.2, with the difference that the sine wave voltage signal may be unbiased.

And 3.4, checking a voltage channel for acquiring the rotating speed. And (3) gradually increasing the duty ratio by using a square wave signal output by the field calibration device, simulating the fluted disc waveform of the unit, and calibrating the rotating speed test precision of the system.

(4) And checking a current channel for collecting pressure pulsation and working condition parameters.

4.1 adopt the on-site calibration device to output the current value I₀Value of current I₀And selecting between 4-20 mA, wherein not less than 8 groups of the current channels are selected, recording the deviation of the acquisition current value and the input current value of the system, and checking the test precision of the current channels.

4.2 adopt on-spot calibration equipment to failOut-of-band offset current sine wave signal, offset current I of signal₀And amplitude I_p-pAmplitude I, which can be determined according to the type of sensor chosen for the system_p-pAnd not less than 3 groups of the current values are recorded, the deviation of the collected current value and the input current value of the system is recorded, and the amplitude analysis function of the system is verified.

4.3 different frequencies and different I modulated with the field-check device_p-pThe frequency component of the synthesized signal should at least comprise a combination of frequency conversion, low frequency and frequency multiplication, and the I of each component of the synthesized signal_p-pThe voltage range should include the main application interval of the system, the frequency value and the amplitude of each component after the system frequency spectrum analysis are recorded, and the frequency spectrum analysis function of the system is verified by comparing the frequency value and the amplitude with the input value.

(5) Repeating the steps (3) and (4) and gradually increasing V_p-pAnd I_P-PAnd (4) until the amplitude response reaches or exceeds an alarm value set by the system, recording the deviation between an input value and a set value during alarm, and verifying the alarm function of the system.

(6) And recording data, generating a report, and then removing the connection between the field calibration device and the monitoring system.

The method of the embodiment takes the online state monitoring system as an organically-connected whole, and the verified content comprises signal acquisition of a hardware part and function analysis of a software part; and a calibration method suitable for the signal channels for collecting different types of stability parameters is provided. The method of the embodiment incorporates the rotation speed measurement into the verification content, and designs a verification method suitable for the rotation speed measurement.

The synthetic signal adopted by the method is set according to the multi-component frequency spectrum characteristics of the stability parameters of the water-turbine generator set, the adopted synthetic signal can construct the stability parameters of the simulation unit, and the analysis function, particularly the frequency spectrum analysis function, of the online state monitoring system software part on the complex signals is verified.

The conventional current channel verification only carries out the precision verification of the average value, and for the channel for testing pressure pulsation, the method has larger defects.

The technical solutions of the present invention are not limited to the above embodiments, and all technical solutions obtained by using equivalent substitution modes fall within the scope of the present invention.