Photoelectric measurement of rotor temperature of generators in Wuhan University Journal of Yue Youlan Jiaozuo University, Henan Jiaozuo 454001 The main business is based on the light absorption characteristics of gallium arsenide semiconductors. A new type of generator rotor temperature measurement system was designed. Using simulation devices, it's dynamic in real time. In the case of non-contact. The generator rotor temperature detection is realized. A successful experimental result was achieved.

To ensure the safe and economic operation of power plant generator sets and prevent them from being seriously damaged, it plays a decisive role in the stable operation of the power system and the uninterrupted power supply for users. The temperature rise of the rotor surface of large steam turbine generators is particularly serious for the additional heat generated at the rotor end and their contacts, which has become an important factor affecting the safe operation of the generator. The traditional method 13 for monitoring the rotor temperature of a generator has a carbon brush slip ring contact measurement radio electronic measurement and infrared temperature measurement. These methods have their own advantages and disadvantages, but it is difficult to achieve multi-point simultaneous monitoring, and the anti-interference ability is poor. At present, the direct test method for monitoring the rotor temperature of large generators is still under study. The research report on the temperature of the generator rotor using the optical characteristics of the phosphor has been reported abroad. The difficulty of this method is difficult to find. A suitable fluorescent substance. We have designed a new type of sensing structure, using this new type of temperature measurement scheme, which has the advantages of simple structure, convenient installation and high non-contact temperature measurement accuracy. Within 70150 Celsius, the temperature difference of analog measurement is within 2, 23.

1 Principle and device of photoelectric temperature measurement 1.1 In a light-absorbing semiconductor in gallium arsenide crystal, when an electron is excited by a photon, two basic types of transitions are caused, namely direct jump and indirect transition, and the forbidden band width of the semiconductor crystal The light absorption process in the crystal is directly related and the forbidden band width is a temperature-dependent monotonic function. The temperature rise of the body causes the forbidden band width to decrease, and the light absorption process in the crystal is strengthened, so that the crystal light jump rate is lowered, and accordingly, temperature check. The gallium arsenide crystal has a high electron hopping rate, a large forbidden band width, and a direct transition type energy. The mechanism is a material for fabricating a semiconductor temperature sensitive element. The temperature-sensitive components used in the actual test are intrinsic gallium arsenide thin bodies.

In the mortar surface, when the thickness of the gallium arsenide crystal reaches a certain value, the light wave having a wavelength smaller than the forbidden band wavelength is hardly absorbed as the incident photon wavelength is longer than the forbidden band wavelength. It is shown that the following formulas establish the power spectrum distribution of the incident light source of the household, the lower limit wavelength and the upper limit wavelength of the light source spectrum; 7 the light energy transmittance corresponding to the temperature; and the arsenic arsenic band gap at the temperature of 7 The width of the visitor wavelength.

The experimental curve obtained by the light source. In the horizontal coordinate temperature, the longitudinal direction of the small light source detector output of the telecommunications, his crystal light transmittance changes cause the detector electrical signal output changes. Due to the spectral work of the white busy source.卞 卞 佰 佰 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , (2) The actual optical signal and the reference optical signal are received by the same photodetector, and are amplified by the same way. There is such a thing. To be straight, this is related to the theoretical formula 2. The experimental result of the semiconductor light-emitting diode 0 is a curve, which is related to its light power distribution. If the curve is differentiated, the obtained differential curve and the spectral power distribution line of 1 are very close, and the progress verifies the correctness of the theoretical formula.

1.2 Two basic methods for detecting the light absorption characteristics of gallium arsenide semiconductors. Principle 3, assuming that the spectrum of the light source used is concentrated nearby, when the temperature rises, the optical power received by the detector is reduced due to the decrease of the transmittance, and the amplitude of the output telecommunications is reduced after the calibration, and the amplitude of the detector is transmitted. The size is used to determine the temperature of the temperature to be measured. In this measurement method, the influence of the fluctuation of the light source should be mainly eliminated.

Sideband wavelength detection method. The basic principle of this kind of temperature measurement method 4, for a fixed thickness of gallium arsenide semiconductor, the band gap energy at a certain temperature value is 1 private and small; the wavelength of the wavelength is the center of the light, when the wavelength of the light is near the heart, Its transmittance is sensitive to temperature. In the right time, the light wave that penetrates into the body absorbs the crystal of the crotch wave, and the wavelength of the side band of the human is 5 is deuterated. The temperature value to be measured can be accurately obtained. The main problem solved by this method is the disturbance of ambient light. On the other hand, when the photodetector and the light source are on the 1 side. This method is limited to 1 in the generator rotor temperature measurement scheme. From the requirements of simple and economical structure, we choose the amplitude detection method to serve the disturbance of various factors such as the wave source of the wave source. 7 views reflect the real temperature signal. In our actual turbine generator rotor dynamics detection requirements and characteristics, cleverly solved the above question 2 transmission rate 7 and temperature relationship curve 10 detector 2 to achieve turbine generator rotor agricultural surface temperature dynamic online detection point position. A convenient way to solve this problem is to introduce the marker signal, which can solve the positioning of the measuring point. It can eliminate interference factors such as changes in the light path of the light source. At the same time, the calibration parameters in the temperature measurement can also be solved by utilizing the characteristic parameters of the semiconductor temperature sensitive element and the marking element itself. The structure of the temperature sensitive element and the marking element are respectively 67.

i, 2 reflection gold film 6 foot semiconductor temperature sensitive pieces of discipline. A wide GaAs crystal is attached to the cylindrical glass substrate to have a thickness of (1) (8) crystal blood polishing, and a reflective gold paste is plated at the interface between the arsenic arsenide crystal and the glass substrate. The light wave portion penetrated into the gallium arsenide crystal is reflected along the original route, and the ratio of the crystal surface reflected light to 2.3+2 and 2 is only related to the characteristic parameter of the semiconductor temperature sensor element such as the blood emissivity gold. Film reflectance and crystal transmittance are 7 sense. In addition to the transmission rate and temperature clearance. Other scenes are fixed.

Set the value of the electrical signal with 3 + 27 inches, no, the signal value corresponding to 2 is used by the team. Their ratio is only related to the crystal temperature. Measure the ratio of the recognition, and by scaling, the temperature at the crystal can be pushed out.

For example, the characteristic 1 has no reflective gold film. The thickness of the gallium arsenide body is larger than this, and the light wave penetrating into the crystal can be completely absorbed by the crystal. The light source detector receives only the surface reflection light number 2, and does not contain the temperature signal, that is, the flag signal ij n, the electrical signal caused by the optical signal reflected back by the gallium arsenide crystal semiconductor temperature sensitive element and returned by the identification component The electrical signal 7 caused by the temperature-independent optical signal is processed and processed by the microcomputer and the corresponding software, and the corresponding measuring point temperature can be obtained.

The transfer coefficient; your detector response is considered to be constant over the spectral range of the source used; 0, the light incident on the crystal face is related to the characteristic parameters of the instrument itself. Therefore, according to this, the temperature calibration and measurement are 1.4 detection circuit. If a semiconductor temperature sensor and a mark element are buried in the rotor and the surface of the turbine generator, the midpoint waveform of the analog electric signal waveform is obtained by the photodetector. The turbine generator rotor rotates at high speed. The temperature signal of the pulse detector 3, the pulse sign signal.

Obviously, in order to correctly obtain the ratio relationship between the electrical signals of the measuring points and the marking signals, it is necessary to be able to maintain and measure the peaks of the electrical signals of the measuring points and the times of the markers. Acquiring the Output Waveform of an Analog Circuit As another aspect, the analog circuit itself should have a logic number that provides a start-up 8, 8 microcontroller 0 converter. And to prevent the false peak detection to maintain the threshold level adjustment function, the signal acquisition shuttle circuit function block of the block 9.

Complete waveform and timing logic 8. 5, respectively, the waveform of the corresponding point in 9.

2 Experimental research In order to study the performance of the temperature measurement system, this paper designed a simulation device. Used to simulate the rotor and condition of the hair dryer and the rotation gauge. The performance of the temperature measurement system was tested on an analog device for a single detection point.

2.1 Dynamic temperature rise and temperature process The temperature measurement experiment uses a heating device to warm and cool the crystal. Simulate the heating and cooling process of the generator rotor. The temperature measurement system measures the crystal surface temperature in real time and records the temperature value of the conventional temperature instrument. The measured values ​​of the ordinate system in the actual two sets of temperature rise and fall curves, the index of the abscissa temperature meter, the measurement curve of the medium temperature rise process, and the measurement curve of the 6 temperature drop process, the two sets of measurement data are performed under the same conditions.

Photoelectric chamber amplifiers, holding controllers, comparators, circuit comparators, 1 and NAND gate sampling, the index error of the integrated one-shot trigger temperature meter is within 4, at 140, the error is 2; As the temperature rises, the temperature measurement value of the temperature measurement system and the temperature meter value tend to. The reason for this phenomenon is that the center wavelength of the illuminating spectrum of the infrared illuminating tube corresponds to the high side of the temperature value.

2.2 System temperature measurement Repeated experiment The repeated parts of the temperature measurement system reflect an important aspect of system performance. For this reason, we have set up the temperature rise experiment at different times, and the obtained temperature measurement curves are respectively experimentally shown in the high temperature zone and the curve of the curve. The repeatability is very good, and there are many factors affecting the repeatability of the gauge value C. The following factors mainly increase the temperature inside the emitter, causing the temperature of the emitter tube to drift, and the center wavelength shifts toward the long wavelength. The influence of vibration noise 3 The GaAs crystal of the temperature sensitive component has poor contact with the simulated rotor to form a temperature difference; there is calibration error, the sensor of the measurement system has nonlinearity, and the sensitivity in the low temperature section is low, that is, the temperature meter 桁 value r signal noise Relatively low. So at 70, the following repeatability is slightly different.

2.3 Temperature measurement system response performance test The actual response speed of the temperature measurement system is very fast, including the display delay time, the measurement of the group temperature data only needs about 48, 圮 real real, measurement system. In order to further investigate the temperature of the temperature measurement system, a temperature test was performed on the process. The heater voltage change process, that is, the actual temperature measurement result 13, the curve is the temperature instrument curve, and the curve 5 is the temperature measurement system measurement curve. The dynamic process reflected by the curve includes the thermal habit of the entire probe head! .

The curve and curve 5 have large differences in the cooling stage. The main reason is the temperature difference between the temperature sensing head and the simulated rotor during the rapid cooling process. Therefore, this tells us that in the actual measurement, the temperature sensitive component should be closely connected with the generator rotor measuring point as much as possible to facilitate the response speed of the edge temperature system.

The heating voltage has changed. The system has the following characteristics. 1 System structure is easy to install and can be contacted in real time. 8 Chen, Liu Xianbin. Stochastic finite element method and its engineering application, Chengdu Southwest Jiaotong University Press, 1993.

Iiq Zhang Wenzheng, Liu Lingyao, Chen Zuyu, et al. Numerical Analysis and Observation Analysis of Stress and Deformation of Tieshan Earth Dam The Proceedings of the First Conference of Soil Mechanics and Basic Engineering of China Civil Engineering Society Beijing, China Construction, page 63 The system has good stability, repeatability, anti-interference and response characteristics.

Compared with the traditional temperature measurement method, multi-point monitoring can be completed, and after proper improvement, the rotor temperature can be detected cyclically.

l Huang Ronghua. Discussion on the temperature measurement method of turbine generator rotor. Dadong 2 Chen Zunrong, Huang Yaoqun, Wang Bin. Non-contact temperature measurement of the synchronous motor rotor. Dongfang Electric, 199524751.

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