1. A precise point inspection method for thermal power equipment is characterized by comprising the following steps:

s1, determining equipment for incorporating precise point inspection; s2, determining the positions and the number of the equipment measuring points; s3, determining a test period; s4, creating a technical means matched with each device according to the working principle and the physicochemical characteristics of each device; s5, testing according to the testing period and the corresponding technical means; s6, evaluating the test result; the equipment test period is determined according to the importance of the equipment, the equipment test period is dynamically adjusted according to the running state of the equipment, and the test frequency is increased when the running state of the equipment is degraded.

2. The precise thermal power equipment point inspection method according to claim 1, wherein the range of the equipment including the precise point inspection is determined according to an importance index of the equipment.

3. The precise thermal power equipment point inspection method according to claim 1 or 2, characterized in that the importance of the equipment comprehensively considers reliability factors, efficacy factors, cost factors, environmental factors and safety factors, and the equipment is divided into particularly important equipment, more important equipment and generally important equipment according to the equipment importance index.

4. The precise point inspection method for thermal power equipment as claimed in claim 3, wherein the particularly important equipment accounts for 10% -15% of the total number of the equipment, the more important equipment accounts for 55% -75% of the total number of the equipment, and the generally important equipment accounts for 15% -30% of the total number of the equipment.

5. The precise thermal power equipment point inspection method according to claim 4, wherein the test period of particularly important equipment is one week, the test period of more important equipment is two weeks, and the test period of generally important equipment is one month.

6. The precise thermal power equipment point inspection method according to claim 1, wherein the method for evaluating the test result comprehensively considers the test value, the change frequency of the test value and the spectral characteristics.

7. The thermal power equipment precision spot inspection method according to claim 6, wherein when the test value does not reach the alarm value, an alarm is given when the change rate of the test value within the specific range under the same test condition is more than 25%, and the alarm does not consider the change rate of the test value when the test value is not within the specific range under the same test condition.

8. The precise thermal power equipment point inspection method according to claim 7, wherein the test value is a vibration value, the specific range means that the vibration value of the rotating equipment is in an unlimited long-term operation area of ISO10816 standard, and when the vibration value is lower than a minimum boundary value of the unlimited long-term operation area, the alarm does not consider the change rate of the vibration value.

9. The thermal power equipment precision spot-checking method as claimed in claim 6, wherein the evaluation of the test result adopts a spectrum characteristic, and the spectrum characteristic comprises a frequency range, a fault characteristic frequency amplitude, a harmonic frequency and a side frequency band.

10. A thermal power plant precision spot check method according to claim 9, wherein the presence of harmonic vibration components of the fault signature indicates increased deterioration of the mechanical problem associated with the fault signature, and wherein an alarm is provided, and wherein a single bearing fault signature vibration component is present with neither a side band nor harmonic vibration components, and wherein tracking detection is enhanced and no repair advice is immediately given.

Background

Because of numerous thermal power equipment, the comprehensive adoption of on-line monitoring will consume huge cost, and the system maintenance is more difficult. And the traditional point inspection can only preliminarily find out the equipment abnormality and can not carry out fault diagnosis. The precise point inspection is to use precise detecting instruments and meters to perform off-line test on the equipment, under the normal operation condition, use detecting instruments such as vibration, infrared, ultrasonic, current spectrum, oil liquid and the like to measure physical quantities representing the operation state of the equipment, analyze, compare and judge according to standards and historical trends, and quantitatively determine the technical condition and the deterioration degree of the equipment.

In a traditional precise point inspection method, a test period is generally uniformly regulated or adjusted by experience, so that each device is treated equally, limited manpower cannot be put on the most important device, the device cannot be adjusted according to the running state of the device, the change of the running state of the device cannot be closely tracked, intervention measures cannot be taken timely often, and the device is damaged; and the evaluation of the traditional precise point inspection method on the test result is generally determined according to an industry standard value, and an emergency accident that the test result is within a standard alarm value but the equipment is damaged often occurs.

The Chinese patent application CN108287529A discloses an integrated inspection, remote precision diagnosis and maintenance system for industrial equipment, which is a system platform integrating team inspection, professional inspection, precision inspection and supervisor inspection, and establishes an integrated equipment inspection, analysis and evaluation and fault precision diagnosis management system for a factory. The invention has the advantages of establishing a standardized industrial equipment management and maintenance system, reducing the operation and maintenance cost of industrial equipment of a factory and improving the production efficiency. It is not disclosed that the device test period is determined according to the importance of the device and is dynamically adjusted according to the operation state of the device, and the test frequency is increased when the operation state of the device is deteriorated.

Disclosure of Invention

In order to overcome the defects of the precision point inspection method, the invention provides the precision point inspection method which can track the equipment degradation trend in time and evaluate the test result more accurately.

The technical scheme adopted by the invention for solving the problems is as follows: a precise point inspection method for thermal power equipment is characterized by comprising the following steps:

s1, determining equipment for incorporating precise point inspection; s2, determining the positions and the number of the equipment measuring points; s3, determining a test period; s4, creating a technical means matched with each device according to the working principle and the physicochemical characteristics of each device; s5, testing according to the testing period and the corresponding technical means; s6, evaluating the test result; the equipment test period is determined according to the importance of the equipment, the equipment test period is dynamically adjusted according to the running state of the equipment, and the test frequency is increased when the running state of the equipment is degraded.

The precise point inspection method for the thermal power equipment determines the test period according to the importance of the equipment, can use advanced technical means on important equipment, saves labor cost, dynamically adjusts the test period according to the running state of the equipment, increases the test frequency when the running state of the equipment is degraded, can closely track the degradation trend of the equipment, and reduces the sudden failure risk of the equipment.

Preferably, the range of equipment for which the precision spot inspection is incorporated is determined according to the importance index of the equipment.

Preferably, the importance of the equipment comprehensively considers reliability factors, efficacy factors, cost factors, environmental factors and safety factors, and the equipment is divided into particularly important equipment, more important equipment and generally important equipment according to the equipment importance index.

Preferably, the total number of the equipment is 10% to 15% of the particularly important equipment, 55% to 75% of the more important equipment, and 15% to 30% of the most important equipment.

Preferably, the particularly important device test period is one week, the more important device test period is two weeks, and the generally important device test period is one month.

Preferably, the method of evaluating the test results takes into account the test values, the frequency of change of the test values, and the spectral characteristics in combination.

For specific faults, the change rate of the test value and the frequency spectrum characteristics can better reflect the running state of the equipment, and compared with a method for evaluating the test result by singly adopting the size of the test value, the method for comprehensively considering the test value, the change rate of the test value and the frequency spectrum characteristics is more reliable and can avoid misjudgment on equipment degradation.

Preferably, when the test value does not reach the alarm value, an alarm should be given when the rate of change of the test value within the specific range is more than 25% under the same test conditions, and the alarm does not consider the rate of change of the test value when the test value is not within the specific range under the same test conditions.

Preferably, the test value is a vibration value, the specific range refers to that the vibration value of the rotating equipment is in an unlimited long-term operation area of the ISO10816 standard, and when the vibration value is lower than a minimum boundary value of the unlimited long-term operation area, the alarm does not consider the change rate of the vibration value.

Preferably, the evaluation of the test results employs spectral characteristics including frequency range, magnitude of fault characteristic frequency amplitude, and harmonics and sidebands.

Preferably, the existence of harmonic vibration components of the fault characteristic frequency indicates that the mechanical problem related to the fault characteristic frequency is degraded, an alarm should be given, and the existence of vibration components of single bearing fault characteristic frequency, which have no side frequency band and no harmonic frequency, should enhance the tracking detection and should not give a maintenance suggestion immediately.

Compared with the prior art, the invention has the following advantages and effects: the invention dynamically adjusts the test period according to the importance and the running state of the equipment, is beneficial to finding out the abnormal development trend of the equipment in time, and takes preventive measures to avoid sudden equipment failure; the method for evaluating the test result by combining the test value, the change rate of the test value and the frequency spectrum characteristic can be used for evaluating the running state of the equipment more accurately.

Drawings

Fig. 1 is a flow chart of a precise point inspection method for thermal power equipment according to the invention.

FIG. 2 is a flow chart of a test period determination method of the present invention.

FIG. 3 is a flow chart of a test result evaluation method of the present invention.

Detailed Description

The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.

Examples

As shown in fig. 1, the precise point inspection method for thermal power equipment disclosed by the invention comprises six steps:

s1, determining the equipment including the precision spot inspection:

specifically, the importance of the equipment can be determined according to reliability factors, efficacy factors, cost factors, environmental factors, safety factors and the like of the equipment, and in order to simplify and make the evaluation process operable, the above influence factors are divided into 4 grades, which are respectively represented by 1, 2, 3 and 4, and the higher the grade is, the greater the influence of the equipment on the system is. Table 1, table 2, table 3, table 4, and table 5 are importance degree score criteria for reliability factors, efficacy factors, cost factors, environmental factors, and safety factors, respectively.

TABLE 1 Scoring criteria for reliability factors

Grade	Effect of device failure on System functionality	Scoring (for spare)	Scoring (No spare)
				1	Has no influence on	10	10
2	Failure of a device causes more device or system failure	20	30
				3	The output is reduced by more than 30 percent	40	70
4	Jumping machine	60	100

TABLE 2 Scoring criteria for efficacy factors

Grade	Effect of Equipment failure on efficacy	Scoring
			1	Has no influence on	10
2	Slightly influencing coal consumption	30
			3	Medium influence on coal consumption	70
4	Seriously affecting coal consumption	100

TABLE 3 Scoring criteria for cost factors

TABLE 4 Scoring criteria for environmental factors

Grade	Impact of equipment failure on environmental safety	Scoring
			1	Has no influence on	10
2	Causing less environmental pollution	30
			3	Causing great environmental pollution	70
4	Violate the environmental regulations and cause serious environmental pollution	100

TABLE 5 Scoring criteria for safety factors

Grade	Impact of equipment failure on safety	Scoring
			1	Has no influence on	10
2	Slightly endangering life of workers and equipment safety	30
			3	The safety of the life and the equipment of the workers is harmed by the medium	70
4	Seriously harming life of workers and equipment safety	100

Determining the importance standard of each factor of the equipment, and calculating the importance index of the equipment in the system:

in the formula: m is_jRespectively representing the grading values of reliability factors, efficacy factors, cost factors, environmental factors and safety factors; f. of_jThe weight values respectively representing the reliability factor, the efficacy factor, the cost factor, the environmental factor and the safety factor can be determined according to 40%, 20%, 20%, 10% and 10% in sequence.

The devices for entering the precision spot inspection range can be selected according to the importance of the devices, for example, the devices with scores greater than 50 are entered the precision spot inspection range, or the number of the devices can be determined first, and the specific device range for entering the precision spot inspection is determined according to the importance index.

S2, determining the positions and the number of the equipment measuring points;

for the convenience of testing, the precision point inspection generally adopts a three-way sensor, the pasting surface of the gasket is completely attached to the measuring point part of the equipment, and the mounting position of the measuring point is determined according to the principle that the transmission path is shortest and the rigidity along the path is greatest. For horizontally-mounted equipment, the gasket is mounted at a position which is 10 degrees lower than the horizontal direction of the bearing seat, and preferably the first channel is in the horizontal direction; for vertically mounted equipment, the shims are mounted on the axial end faces of the bearing blocks. If the field device fails to meet the aforementioned installation conditions, it may be installed at an angle of 45 ° to the horizontal.

The number of the measuring points is determined according to the '800 mm criterion', namely when the bearing span on the same shaft is larger than 800mm, two gaskets are preferably arranged; when the bearing span is less than 800mm, a shim is preferably installed. Whether the equipment is installed horizontally or vertically, a measuring point is arranged at the position of the thrust bearing, and a gasket is installed. For the equipment for temporary test, the sensor can be fixed by a magnetic base instead of a gasket.

S3, determining a test period;

specifically, the equipment is firstly classified into A, B, C types according to the equipment importance index calculated in S1, wherein the A type equipment is critical and particularly important equipment and generally accounts for 10-15% of the total number of the equipment; the B-type equipment is critical and relatively important equipment and generally accounts for 55 to 75 percent of the total number of the equipment; class C devices are non-critical, generally important devices, typically accounting for 15% to 30% of the total number of devices. Determining a test period according to the equipment type, wherein the A-type equipment is recommended to test once a week, the B-type equipment is recommended to test once every two weeks, and the C-type equipment is recommended to test once a month; in addition, for the equipment for detecting the abnormality, the trend tracking should be strengthened, and the testing frequency should be increased appropriately, for example, when the variation rate of the testing value is more than 25% under the same condition, the testing frequency should be increased, and the testing can be performed once a day. The 300MW unit importance index and test period are shown in Table 6.

TABLE 6 importance index and test period

Numbering	Device name	Importance index	Categories	Test period (sky)
					1	Draught fan	66	A	7
2	Water supply pump	66	A	7
					3	Shaft-added fan	18	B	14
4	Public water pump	18	B	14
					5	Air compressor	20	B	14
6	Industrial water pump	18	B	14
					7	Urea delivery pump	10	C	30
8	Desalting water pump	12	C	30

The equipment testing period is determined according to the equipment importance and the running state, limited manpower is put into the most important work, and the work efficiency of point inspection can be greatly improved.

And S4, creating a technical means matched with the device according to the working principle and the physicochemical characteristics of each device.

Specifically, according to the working principle and the physicochemical characteristics of each device, a technical means, namely a technical matrix, matched with each device is created, the technical means includes vibration, current spectrum, infrared, ultrasonic, oil liquid and other analysis and detection technologies, but is not limited to the five technologies, and other technical means can be incorporated according to the need of device point inspection. The technical means used by a 300MW unit part of the equipment is shown in Table 7.

TABLE 7 dot inspection matrix for equipment

And S5, testing according to the test period and the corresponding technical means:

and carrying out tests according to the equipment list determined in the step S1, the station positions determined in the step S2 and the test period determined in the step S3, and dynamically adjusting the test period according to the test results.

S6, evaluation test results:

specifically, the detection result is evaluated by comprehensively considering the test value, the spectral feature, and the variation tendency of the test value. The test values generally comprise a vibration pass frequency value, an ultrasonic value, an infrared temperature value, oil granularity, moisture, a current spectrum dB-down value and the like. The spectral features include a vibration spectrum, an ultrasonic spectrum, and the like.

The evaluation method of S6 will be described in detail below by taking the vibration detection technical means as an example, and the evaluation methods of other detection technical means are similar and will not be described one by one.

According to the standard ISO10816, the state in which the rotating equipment is located is divided into four zones, zone a, where the vibrations of the newly delivered equipment generally fall; the vibration of the equipment in the area is generally considered to be capable of running for an unlimited long time; the equipment vibration is in the area, which is generally not suitable for long-time continuous operation, and the equipment can normally operate for a limited time in the state until a proper time for taking remedial measures is available; the vibration of the equipment in this area is generally considered to be of sufficient intensity to cause damage to the equipment.

The boundary value of A, B, C, D area is shown in Table 8 for large equipment with rated power more than 300kW and less than 50MW and the height H of the rotating shaft more than or equal to 315 mm.

TABLE 8 vibration value region Classification

Generally, when the equipment vibration is above the C region boundary value specified by the ISO10816 standard, an alarm is given. As shown in Table 8, for rigid support, the boundary value of the C area is 4.5mm/s, namely for the equipment, when the vibration value is greater than or equal to 4.5mm/s, an alarm is given, and machine selection and maintenance are recommended; for flexible supports, the boundary of the C area is 7.1mm/s, namely for the equipment, when the vibration value is greater than or equal to 7.1mm/s, an alarm is given, and machine selection and maintenance are recommended. Other types of devices the standards are also specified and are not listed here.

However, the thermal power plant often has a fault that the vibration value does not exceed the standard, that is, the vibration value does not reach the boundary value of the region C, and the equipment is damaged, and the invention provides an evaluation method based on the variation trend and the spectrum characteristic, which is supplemented, as shown in fig. 2.

When significant changes in the vibration values occur, even if the zone C boundary specified by the standard ISO10816 is not reached, measures should be taken which can be produced instantaneously or which develop gradually over time and which may indicate early damage or some other problem.

The vibration tests to be compared should be conducted at the same sensor location and orientation and under substantially the same operating conditions of the equipment. It is desirable to study the significant variation from the normal vibration value (no matter what the pass frequency vibration value is), so as to avoid the dangerous situation. These changes are preferably considered significant when they exceed 25% of the upper limit of the region B as specified by the standard ISO10816, in particular if they occur suddenly, at which point diagnostic studies should be undertaken to ascertain the cause of the change and to determine appropriate measures for the next step. It should be noted that the 25% value is merely a general guideline for significant variations in vibration magnitude, and that other values may be used empirically for a particular device.

Further, for some specific faults, when the vibration value and the variation trend of the vibration value are small, the equipment may be damaged, for example: the characteristic frequency of the rolling bearing retainer with smaller amplitude can cause serious bearing damage and failure, and therefore, the characteristic frequency should be comprehensively considered in combination with the frequency spectrum characteristic.

For the evaluation of the detection result of the rolling bearing, the evaluation is carried out according to the frequency spectrum characteristics, and the fault development of the rolling bearing can be divided into four stages: an initial stage, a second stage, a third stage, and a fourth stage. The corresponding fault degrees are respectively slight, moderate, severe and critical, the characteristics of each stage are different, and the fault severity degrees are different.

In the initial stage (slight) of the fault of the rolling bearing, the vibration amplitude is small, noise is generated, the demodulation waveform can show very short impact, and the frequency range is 5kHz-40 kHz; the second stage (moderate) of the rolling bearing fault, friction and smaller impact, the envelope demodulation frequency spectrum can show the characteristic frequency of the fault, and the frequency range is 1kHz-5 kHz; in the third stage (serious) of the fault of the rolling bearing, the ultrahigh frequency amplitude is continuously increased, harmonic waves generated by impact and side frequency components formed by load periodic variation modulation appear, and the characteristic frequency of the fault of the bearing is seen to have a peak value; in the fourth stage (emergency) of the rolling bearing fault, the ultrahigh frequency amplitude is reduced, the periodic vibration is reduced, the background noise is obviously increased, a hay pile is formed and continues to develop, the characteristic frequency of the hay pile disappears completely, and the frequency spectrum is more like a rotary loosening mode.

In addition, the severity of the equipment problem is related to several other characteristics, such as harmonics, sidebands, etc., that may be manifested by the equipment hazard problem. Harmonic frequency: the existence of harmonic vibration components of the fault characteristic frequency of the equipment indicates that the mechanical problem related to the fault characteristic frequency is degraded and aggravated; side band: the method is very common in fault spectrograms of rolling bearings, gear boxes and the like, and is an important basis for judging the severity of faults, such as the damage problem of inner rings, cages and the like of rolling bearings and the abrasion problem of gears; for the analysis of the severity of the fault of specific equipment, such as bearing abrasion, poor meshing of a gearbox and the like, a plurality of frequency characteristics are combined to give a maintenance suggestion; for example, a single vibration component with the bearing fault characteristic frequency, which has no side frequency band and no harmonic frequency, exists, the tracking detection is preferably enhanced, and a maintenance suggestion is not preferably given immediately.

Those not described in detail in this specification are well within the skill of the art.

Although the present invention has been described with reference to the above embodiments, it should be understood that the scope of the present invention is not limited thereto, and that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention.