Device and method for calibrating port mechanical insulating coating detector

Abstract

The invention discloses a calibration device and method for a port mechanical insulating coating detector. The device comprises an adjustable standard resistance box, a digital multimeter and a high-precision current sensor, the adjustable standard resistance box and the digital multimeter are both connected with the insulating coating detector, and the high-precision current sensor passes through the insulating coating detector to be closed and fed back to measure the current. According to the calibration device and method for the port mechanical insulating coating detector provided by the invention, the problem of high-precision calibration of multi-threshold voltage, resistance and current of the insulating coating detector is solved, an uncertainty evaluation model is constructed for resistance parameters, and uncertainty factors influencing a measurement result are analyzed. The device is complete in function, compact in structure, scientific and reasonable in calibration method and good in reproducibility, has good innovativeness and popularization and application value, and effectively guarantees the accuracy and stability of measurement results of the insulating coating detector and the credibility of data.

Description

Technical Field

[0001] This invention belongs to the field of transportation and waterway technology, and specifically relates to a calibration device and method for a surface insulation coating tester for port lifting and loading machinery. Background Technology

[0002] Ports, as an important component of the national comprehensive transportation network and a vital strategic resource for economic and social development, are crucial supports for accelerating the construction of a strong transportation nation and building a modern industrial system. Port machinery is the core equipment for the intelligent, green, and integrated development of ports, and its quality directly affects the safety and efficiency of port operations.

[0003] Currently, most port machinery is made of cast iron with a surface coating of insulating, rust-proof, and corrosion-resistant materials. Due to environmental factors such as humidity and salt spray in ports, poor coating quality can easily lead to surface and critical component corrosion during operation, resulting in decreased insulation. This can range from affecting operational accuracy and efficiency, and accelerating component aging, to, with prolonged full-load operation, accelerating the overall performance degradation of the port machinery, causing significant safety hazards and economic losses. Therefore, with the construction of smart and safe ports, for port machinery operating in the open, in addition to installing long-term monitoring sensors for stress and strain at key nodes, the insulation of surfaces requiring insulation must be regularly tested. If leaks are found, an insulation coating detector should be used to confirm their location, thereby ensuring the operational safety of the port machinery.

[0004] An insulation coating tester is an instrument used to detect defects such as tiny pores and cracks on the surface of coatings on port machinery. Figure 1 This is a schematic diagram of the structure of an existing insulation coating testing instrument. Figure 1As shown, the insulation coating detector 100 includes a multi-threshold detection alarm unit 1001, a probe 1002, and a grounding wire 1003. The multi-threshold detection alarm unit 1001 has multiple voltage values ​​for different coating thicknesses, typically not exceeding 500 μm, and is bolted to the probe 1002. The probe 1002 is made of a material with good water absorption properties, such as sponge or polyurethane. One end of the grounding wire 1003 is connected to the multi-threshold detection alarm unit 1001, and the other end is connected to the exposed surface of the port machinery connected to the detection area. Its working principle is mainly based on the electrical circuit detection method. During operation, the probe 1002, wetted with conductive liquid, slides in contact with the coating on the port machinery surface to detect the location of pores and cracks. At the locations of pores and cracks, the multi-threshold detection alarm unit 1001, probe 1002, port machinery inspection area, and grounding wire 1003 form a closed loop, generating a loop current. When the loop resistance drops below the preset insulation resistance threshold of the insulation coating detector 100, the insulation coating detector 100 emits an audible and visual alarm signal, thereby determining the location of the pores and cracks. It features convenient operation, accurate positioning, and high precision. Its key metrological parameters are the voltage and resistance indication errors for detecting different coating thicknesses, and the current changes during resistance variations. Currently, there is no mature method to calibrate these parameters, thus affecting the accuracy and data reliability of the insulation coating detector.

[0005] Therefore, researching a calibration device and method for a port machinery insulation coating tester, and calibrating its parameters such as voltage, resistance, and current to improve the accuracy of its data in port machinery insulation coating testing, is of great significance and value for improving port machinery operation safety and efficiency, reducing operational risks, and reducing costs and increasing efficiency. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a calibration device and method for a port machinery insulation coating tester, thereby achieving high-precision calibration of parameters such as voltage, current, and resistance of the port machinery insulation coating tester.

[0007] To achieve the above objectives, the calibration device for the port machinery insulation coating tester provided by this invention includes a multi-threshold detection alarm unit, a probe, and a grounding wire; wherein: the multi-threshold detection alarm unit and the probe are fastened together by bolts; one end of the grounding wire is connected to the multi-threshold detection alarm unit, and the other end is connected to the exposed surface of the port machinery connected to the detection area; the calibration device for the port machinery insulation coating tester includes an adjustable standard resistance box, a digital multimeter, and a high-precision current sensor; wherein: the adjustable standard resistance box is connected in series with the insulation coating tester and in parallel with the digital multimeter; the high-precision current sensor is electrically connected to the digital multimeter and is used to measure the closed-loop current formed by the insulation coating tester and the adjustable standard resistance box by electromagnetic induction.

[0008] The adjustable standard resistance box 200 is a ZX25a type adjustable standard resistance box. One end is connected to the probe, and the other end is connected to the multi-threshold detection alarm unit through a grounding wire. The measurement range is 100Ω~100kΩ, and the maximum permissible error is no more than 1%.

[0009] The digital multimeter used is the FLUKE 8588A model. The positive terminal of its voltage measurement port is connected to the probe, and the negative terminal of the voltage measurement port is connected to the multi-threshold detection alarm unit via a grounding wire. The current measurement port is connected to a high-precision current sensor with an upper limit of 200V, a measurement resolution of not less than 0.1V, an impedance of not less than 1GΩ, and an expanded uncertainty of the voltage measurement result that is less than 1 / 3 of the maximum permissible error of the voltage of the insulation coating detector.

[0010] The high-precision current sensor is the SCTH60 model, with a measurement accuracy of not less than 1mA and an aperture of not less than 20mm.

[0011] The calibration method for the calibration device using a port machinery insulation coating tester provided by this invention includes the following steps performed in sequence:

[0012] a001: Zero all ranges of the adjustable standard resistor box, and the insulation coating detector is in an open circuit state;

[0013] a002: The multi-threshold detection alarm unit is sequentially switched to each voltage level. At each voltage level, the voltage value at that voltage level is measured using a digital multimeter. The arithmetic mean of the three measurements is taken as the actual output voltage value of the insulation coating detector. Then, it is compared with the nominal voltage value of the insulation coating detector at that voltage level according to formula (1) to obtain the relative error of the voltage indication of the insulation coating detector at the i-th voltage level, so as to realize the calibration of the voltage parameter.

[0014] (1);

[0015] In the formula:

[0016] —The arithmetic mean of three voltage measurements taken by the digital multimeter at the i-th voltage range, i=1,2,3,...,V;

[0017] —The nominal voltage value, V, of the insulation coating tester at the i-th voltage level;

[0018] —The relative error of the voltage reading of the insulation coating tester at the i-th voltage level, in V;

[0019] a003: The multi-threshold detection alarm unit is switched to each voltage level in sequence. At each voltage level, according to the nominal insulation resistance value corresponding to each voltage level of the insulation coating tester, the resistance value of the adjustable standard resistance box is gradually reduced from 1.2 times the nominal insulation resistance value corresponding to each voltage level. As the resistance value decreases, the loop current measured by the high-precision current sensor gradually increases. When the multi-threshold detection alarm unit starts to alarm, the resistance value of the adjustable standard resistance box is recorded. The arithmetic mean of the three measured resistance values ​​is taken as the actual output threshold resistance value of the insulation coating tester. It is compared with the nominal threshold resistance value of the insulation coating tester according to formula (2) to obtain the relative error of the resistance indication value of the insulation coating tester at the i-th voltage level, so as to realize the calibration of the resistance parameter.

[0020] (2);

[0021] In the formula:

[0022] —The arithmetic mean of the resistance values ​​measured by the digital multimeter at the i-th voltage range, i=1,2,3,...,Ω;

[0023] —The nominal threshold resistance value, in Ω, of the insulation coating tester at the i-th voltage level;

[0024] —The relative error of the resistance reading of the insulation coating tester at the i-th voltage level, in Ω;

[0025] a004: Set the multi-threshold detection alarm unit to each voltage level in sequence. At each voltage level, adjust the resistance value of the adjustable standard resistance box to the nominal insulation resistance value corresponding to each voltage level. Use a high-precision current sensor to measure the current value at this time. Repeat the measurement n times at each voltage level. Take the arithmetic mean of the current values ​​measured n times. Then, calibrate the current parameter according to formula (3) to obtain the relative error of the current indication of the insulation coating detector at the i-th voltage level.

[0026] (3);

[0027] In the formula:

[0028] —The arithmetic mean of the loop current values ​​measured n times at the i-th voltage level by the high-precision current sensor, i=1,2,3,...,mA;

[0029] —The loop current value measured by the high-precision current sensor at the i-th voltage level for the j-th time, in mA;

[0030] —The relative error of the current reading of the insulation coating tester at the i-th voltage level, mA;

[0031] n — the number of times the high-precision current sensor measures the current at each voltage level, n≥10.

[0032] The method for evaluating the uncertainty of resistance measurement results of the calibration device for the port machinery insulation coating tester provided by this invention includes the following steps performed in sequence:

[0033] b001: Establish the uncertainty evaluation model for resistance measurement results according to formula (4):

[0034] (4);

[0035] In the formula:

[0036] —The relative error of the resistance reading of the insulation coating tester, in Ω;

[0037] —The nominal resistance value of the insulation coating tester, in Ω;

[0038] —The reading of the adjustable standard resistance box, in Ω;

[0039] — The change in resistance value caused by ambient temperature and humidity, in Ω.

[0040] b002: Based on the above uncertainty evaluation model for resistance measurement results, the propagation rate is calculated according to formula (5), and the sensitivity coefficient is calculated according to formula (6):

[0041] (5);

[0042] , , (6);

[0043] b003: A certain voltage in the multi-threshold detection alarm unit At the specified voltage level, based on the nominal insulation resistance value corresponding to that voltage level of the insulation coating tester, the resistance value of the adjustable standard resistance box is gradually decreased, starting from 1.2 times the nominal insulation resistance value corresponding to the voltage level. As the resistance value decreases, the loop current measured by the high-precision current sensor gradually increases. When the multi-threshold detection alarm unit starts to alarm, the resistance value of the adjustable standard resistance box is recorded, and the arithmetic mean of n measured resistance values ​​is taken as the actual threshold resistance value output by the insulation coating tester. Then, the measurement uncertainty introduced by the adjustable standard resistance box is calculated according to formula (7). :

[0044] (7);

[0045] b004: The resistance parameter calibration device is the adjustable standard resistance box. The measurement uncertainty introduced by the adjustable standard resistance box is evaluated using a type B method. If the maximum permissible error of the adjustable standard resistance box within the nominal insulation resistance value range corresponding to this voltage range is a, then the half-width is a / 2. It is estimated that it is uniformly distributed. The measurement uncertainty introduced by the adjustable standard resistance box is calculated according to formula (8). :

[0046] (8);

[0047] b005: The entire calibration process is conducted in a temperature and humidity-controlled laboratory environment. The change in resistance caused by ambient temperature and humidity is negligible. ;

[0048] b006: Due to the nominal resistance value of the insulation coating tester The reading of the adjustable standard resistance box Based on equations (5) to (8) above, the combined standard uncertainty of the resistance parameter measurement results of the insulation coating tester is calculated according to formula (9). :

[0049] (9);

[0050] b007: Taking the coverage factor k=2, based on the above combined standard uncertainty... The expanded uncertainty of the resistance parameter measurement result of the insulation coating tester is calculated according to formula (10):

[0051] (10);

[0052] The calibration device and method for a port machinery insulation coating tester provided by this invention solves the problem of high-precision calibration of multi-threshold voltage, resistance, and current in insulation coating testers. An uncertainty assessment model is constructed for the resistance parameter, and the factors affecting the uncertainty of the measurement results are analyzed. The device is fully functional, compact in structure, and the calibration method is scientific, reasonable, and reproducible. It has good innovation and application value, effectively ensuring the accuracy, stability, and reliability of the measurement results of the insulation coating tester. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the structure of an existing insulation coating tester.

[0054] Figure 2 Schematic diagram of the calibration device for the port machinery insulation coating tester provided by the present invention;

[0055] Figure 3 (a) and (b) are flowcharts of the calibration method and uncertainty assessment method for the port machinery insulation coating tester provided by the present invention, respectively.

[0056] Figure 4 The graph shows the corresponding changes in various parameter values ​​during the calibration process of the port machinery insulation coating tester provided by this invention. Detailed Implementation

[0057] The calibration device and method for testing the insulating coating of port machinery provided by the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0058] like Figure 2 As shown, the calibration device for the port machinery insulation coating tester provided by the present invention includes an adjustable standard resistance box 200, a digital multimeter 300, and a high-precision current sensor 400; wherein, the adjustable standard resistance box 200 is connected in series with the insulation coating tester 100 and in parallel with the digital multimeter 300; the high-precision current sensor 400 is electrically connected to the digital multimeter 300 and is used to measure the closed loop current formed by the insulation coating tester 100 and the adjustable standard resistance box 200 by electromagnetic induction.

[0059] The adjustable standard resistance box 200 is a ZX25a type adjustable standard resistance box. One end is connected to the probe 1002, and the other end is connected to the multi-threshold detection alarm unit 1001 through the grounding wire 1003. The measurement range is 100Ω~100kΩ, and the maximum permissible error is no more than 1%. It is used to calibrate the threshold resistance of the insulation coating detector 100.

[0060] The digital multimeter 300 is a FLUKE 8588A model. Its voltage measurement port positive terminal is connected to probe 1002, and its voltage measurement port negative terminal is connected to multi-threshold detection alarm unit 1001 via grounding wire 1003. The current measurement port is connected to a high-precision current sensor 400 with an upper limit of 200V, a measurement resolution of not less than 0.1V, and an impedance of not less than 1GΩ. The expanded uncertainty of the voltage measurement result should be less than 1 / 3 of the maximum permissible error of the voltage of the insulation coating detector 100. It is used to calibrate the voltage and current of the insulation coating detector 100.

[0061] The high-precision current sensor 400 is an SCTH60 model high-precision current sensor with a measurement accuracy of not less than 1mA and an aperture of not less than 20mm. It is used to measure the consistency of the circuit current as the resistance of the adjustable standard resistance box 200 changes.

[0062] like Figure 3 As shown in (a), the calibration method for a port machinery insulation coating tester provided by the present invention includes the following steps performed in sequence:

[0063] a001: Set all ranges of the adjustable standard resistance box 200 to zero, and put the insulation coating tester 100 in an open-circuit state.

[0064] a002: The multi-threshold detection alarm unit 1001 is sequentially switched to each voltage level. At each voltage level, the voltage value at that voltage level is measured using a digital multimeter 300. The arithmetic mean of the three measurements is taken as the actual output voltage value of the insulation coating detector 100. Then, it is compared with the nominal voltage value of the insulation coating detector 100 at that voltage level according to formula (1) to obtain the relative error of the voltage indication value of the insulation coating detector 100 at the i-th voltage level, so as to realize the calibration of the voltage parameter.

[0065] (1);

[0066] In the formula:

[0067] —The digital multimeter 300 measures the voltage three times at the i-th voltage range, i=1,2,3,...,V;

[0068] —The nominal voltage value, V, of the insulation coating tester 100 at the i-th voltage level;

[0069] —The relative error of the voltage reading of the insulation coating tester 100 at the i-th voltage level, in V;

[0070] a003: The multi-threshold detection alarm unit 1001 is sequentially switched to each voltage level. At each voltage level, according to the nominal insulation resistance value corresponding to each voltage level of the insulation coating tester 100, the resistance value of the adjustable standard resistance box 200 is gradually reduced from 1.2 times the nominal insulation resistance value corresponding to each voltage level. As the resistance value decreases, the loop current measured by the high-precision current sensor 400 gradually increases. When the multi-threshold detection alarm unit 1001 starts to alarm, the resistance value of the adjustable standard resistance box 200 is recorded. The arithmetic mean of the three measured resistance values ​​is taken as the actual output threshold resistance value of the insulation coating tester 100. It is compared with the nominal threshold resistance value of the insulation coating tester 100 according to formula (2) to obtain the relative error of the resistance indication value of the insulation coating tester 100 at the i-th voltage level, so as to realize the calibration of the resistance parameter.

[0071] (2);

[0072] In the formula:

[0073] —The arithmetic mean of the resistance values ​​measured by the digital multimeter 300 at the i-th voltage range, i=1,2,3,...,Ω;

[0074] —The nominal threshold resistance value of the insulation coating tester 100 at the i-th voltage level, in Ω;

[0075] —The relative error of the resistance reading of the insulation coating tester 100 at the i-th voltage level, in Ω;

[0076] a004: Set the multi-threshold detection alarm unit 1001 to each voltage level in sequence. At each voltage level, adjust the resistance value of the adjustable standard resistance box 200 to the nominal insulation resistance value corresponding to each voltage level. Use the high-precision current sensor 400 to measure the current value at this time. Repeat the measurement n times at each voltage level. Take the arithmetic mean of the current values ​​measured n times. Then, calibrate the current parameter according to formula (3) to obtain the relative error of the current indication value of the insulation coating detector 100 at the i-th voltage level.

[0077] (3);

[0078] In the formula:

[0079] —The arithmetic mean of the loop current values ​​measured n times at the i-th voltage level by the high-precision current sensor 400, i=1,2,3,...,mA;

[0080] —The loop current value measured by the high-precision current sensor 400 at the i-th voltage level for the j-th time, in mA;

[0081] —The relative error of the current reading of the insulation coating tester 100 at the i-th voltage level, mA;

[0082] n — the number of times the high-precision current sensor 400 measures the current at each voltage level, n≥10.

[0083] like Figure 3 As shown in (b), the method for evaluating the uncertainty of resistance measurement results in a port machinery insulation coating tester provided by the present invention includes the following steps performed in sequence:

[0084] b001: Establish the uncertainty evaluation model for resistance measurement results according to formula (4):

[0085] (4);

[0086] In the formula:

[0087] —The relative error of the resistance reading of the insulation coating tester 100, in Ω;

[0088] —The nominal resistance value of the insulation coating tester 100, in Ω;

[0089] —The reading of the adjustable standard resistance box 200, in Ω;

[0090] — The change in resistance value caused by ambient temperature and humidity, in Ω.

[0091] b002: Based on the above uncertainty evaluation model for resistance measurement results, the propagation rate is calculated according to formula (5), and the sensitivity coefficient is calculated according to formula (6):

[0092] (5);

[0093] , , (6);

[0094] b003: A certain voltage in the multi-threshold detection alarm unit 1001 At the specified voltage level, based on the nominal insulation resistance value corresponding to that voltage level of the insulation coating tester 100, the resistance value of the adjustable standard resistance box 200 is gradually decreased, starting from 1.2 times the nominal insulation resistance value corresponding to the voltage level. As the resistance value decreases, the loop current measured by the high-precision current sensor 400 gradually increases. When the multi-threshold detection alarm unit 1001 starts to alarm, the resistance value of the adjustable standard resistance box 200 is recorded, and the arithmetic mean of n measured resistance values ​​is taken as the actual threshold resistance value output by the insulation coating tester 100. Then, the measurement uncertainty introduced by the adjustable standard resistance box 200 is calculated according to formula (7). :

[0095] (7);

[0096] b004: The resistance parameter calibration device is the adjustable standard resistance box 200. The measurement uncertainty introduced by the adjustable standard resistance box 200 is evaluated using a type B method. If the maximum permissible error of the adjustable standard resistance box 200 within the nominal insulation resistance value range corresponding to this voltage range is a, then the half-width is a / 2. It is estimated that it is uniformly distributed. The measurement uncertainty introduced by the adjustable standard resistance box 200 is calculated according to formula (8). :

[0097] (8);

[0098] b005: The entire calibration process is conducted in a temperature and humidity-controlled laboratory environment. The change in resistance caused by ambient temperature and humidity is negligible. ;

[0099] b006: Due to the nominal resistance value of the insulation coating tester 100 The reading of the adjustable standard resistance box 200 Based on equations (5) to (8) above, the combined standard uncertainty of the resistance parameter measurement results of the insulation coating tester 100 is calculated according to formula (9). :

[0100] (9);

[0101] b007: Taking the coverage factor k=2, based on the above combined standard uncertainty... The expanded uncertainty of the resistance parameter measurement result of the insulation coating tester 100 is calculated according to formula (10):

[0102] (10);

[0103] like Figure 4 As shown, the voltage ranges of the insulation coating tester 100 are u1, u2, u3, ... . At voltage range u1, the resistance value of the adjustable standard resistance box 200 is adjusted to R. 11 Resistance value R 11 It is 1.2 times the nominal threshold resistance value under voltage level u1, and the corresponding current value is i. 11 At this time, the insulation coating detector 100 did not issue an alarm signal, as the resistance value of the adjustable standard resistance box 200 decreased to R. 12 The corresponding current value increases to i 12 At this time, the insulation coating detector 100 issues an alarm signal, R 12 This is the threshold resistance value at voltage level u1; at voltage level u2, the resistance value of the adjustable standard resistance box 200 is adjusted to R. 21 Resistance value R 21 This is 1.2 times the nominal threshold resistance value at voltage level u2, corresponding to a current value of i. 21 At this time, the insulation coating detector 100 did not issue an alarm signal, as the resistance value of the adjustable standard resistance box 200 decreased to R. 22 The corresponding current value increases to i 22 At this time, the insulation coating detector 100 issues an alarm signal, and the resistance value R... 22 This is the threshold resistance value at voltage level u2; at voltage level u3, the resistance value of the adjustable standard resistance box 200 is adjusted to R. 31 Resistance value R 31 The nominal threshold resistance value is 1.2 times that of voltage level u3, and the corresponding current value is i. 31 At this time, the insulation coating detector 100 did not issue an alarm signal, as the resistance value of the adjustable standard resistance box 200 decreased to R. 32 The corresponding current value increases to i 32 At this time, the insulation coating detector 100 issues an alarm signal, and the resistance value R... 32 This is the threshold resistance value under voltage level u3.

[0104] During operation, firstly, in an open-circuit state, the voltage value of the insulation coating detector 100 at different ranges is measured by the digital multimeter 300 and compared with the nominal voltage value at that range to calibrate the voltage parameter indication error. Then, the actual threshold resistance value when the insulation coating detector 100 issues an alarm signal at different ranges is measured by the adjustable standard resistance box 200 and compared with the nominal threshold resistance value at that range to calibrate the resistance parameter indication error. Finally, the current value at different ranges is measured by the high-precision current sensor 400, and the repeatability of the current parameter is calibrated according to the Bessel formula. For the resistance parameter, an uncertainty assessment model is constructed, including multiple factors such as the insulation coating detector 100, the adjustable standard resistance box 200, and environmental conditions. By analyzing the uncertainty components of the measurement results caused by each factor, the uncertainty analysis and assessment of the resistance measurement results are achieved. The uncertainty assessment methods for other parameter measurement results can be carried out with reference to the resistance parameter assessment methods.

[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A calibration device for a port machinery insulation coating tester, the insulation coating tester (100) comprising a multi-threshold detection alarm unit (1001), a probe (1002), and a grounding wire (1003); wherein: The multi-threshold detection alarm unit (1001) and the probe (1002) are fastened together by bolts; one end of the grounding wire (1003) is connected to the multi-threshold detection alarm unit (1001), and the other end is connected to the exposed surface of the port machinery connected to the detection area; the port machinery insulation coating tester calibration device includes an adjustable standard resistance box (200), a digital multimeter (300) and a high-precision current sensor (400); wherein, the adjustable standard resistance box (200) is connected in series with the insulation coating tester (100) and in parallel with the digital multimeter (300); the high-precision current sensor (400) is electrically connected to the digital multimeter (300) and is used to measure the closed loop current formed by the insulation coating tester (100) and the adjustable standard resistance box (200) by electromagnetic induction.

2. The calibration device for the port machinery insulation coating tester according to claim 1, characterized in that: The adjustable standard resistance box (200) is a ZX25a type adjustable standard resistance box. One end is connected to the probe (1002), and the other end is connected to the multi-threshold detection alarm unit (1001) through the grounding wire (1003). The measurement range is 100Ω~100kΩ, and the maximum permissible error is no more than 1%.

3. The calibration device for the port machinery insulation coating tester according to claim 1, characterized in that: The digital multimeter (300) is a FLUKE 8588A digital multimeter. Its voltage measurement port is connected to the probe (1002) with the positive terminal and the voltage measurement port is connected to the multi-threshold detection alarm unit (1001) via the grounding wire (1003). The current measurement port is connected to a high-precision current sensor (400). The upper limit of the range is not less than 200V, the measurement resolution is not less than 0.1V, the impedance is not less than 1GΩ, and the expanded uncertainty of the voltage measurement result should be less than 1 / 3 of the maximum permissible error of the voltage of the insulation coating tester (100).

4. The calibration device for the port machinery insulation coating tester according to claim 1, characterized in that: The high-precision current sensor (400) is selected from the SCTH60 model high-precision current sensor, with a measurement accuracy of not less than 1mA and an aperture of not less than 20mm.

5. A calibration method for a calibration device using a port machinery insulation coating tester according to any one of claims 1 to 4, characterized in that: The calibration method includes the following steps performed in sequence: a001: Set all ranges of the adjustable standard resistance box (200) to zero, and put the insulation coating tester (100) in an open circuit state; a002: The multi-threshold detection alarm unit (1001) is sequentially switched to each voltage level. At each voltage level, the voltage value at that voltage level is measured using a digital multimeter (300). The arithmetic mean of the three measurements is taken as the actual output voltage value of the insulation coating detector (100). Then, it is compared with the nominal voltage value of the insulation coating detector (100) at that voltage level according to formula (1) to obtain the relative error of the voltage indication of the insulation coating detector (100) at the i-th voltage level, so as to realize the calibration of the voltage parameter. （1）； In the formula: —The arithmetic mean of three voltage measurements taken by the digital multimeter (300) at the i-th voltage range, i=1,2,3,...,V; —The nominal voltage value, V, of the insulation coating tester (100) at the i-th voltage level; —The relative error of the voltage reading of the insulation coating tester (100) at the i-th voltage level, in V; a003: The multi-threshold detection alarm unit (1001) is sequentially switched to each voltage level. At each voltage level, according to the nominal insulation resistance value corresponding to each voltage level of the insulation coating tester (100), the resistance value of the adjustable standard resistance box (200) is gradually reduced from 1.2 times the nominal insulation resistance value corresponding to each voltage level. As the resistance value decreases, the loop current measured by the high-precision current sensor (400) gradually increases. When the multi-threshold detection alarm unit (1001) starts to alarm, the resistance value of the adjustable standard resistance box (200) is recorded. The arithmetic mean of the three measured resistance values ​​is taken as the actual output threshold resistance value of the insulation coating tester (100). It is compared with the nominal threshold resistance value of the insulation coating tester (100) according to formula (2) to obtain the relative error of the resistance indication value of the insulation coating tester (100) at the i-th voltage level, so as to realize the calibration of the resistance parameter. （2）； In the formula: —The arithmetic mean of the resistance values ​​measured three times at the i-th voltage range by the digital multimeter (300), i=1,2,3,...,Ω; —The nominal threshold resistance value, Ω, of the insulation coating tester (100) at the i-th voltage level; —The relative error of the resistance reading of the insulation coating tester (100) at the i-th voltage level, in Ω; a004: Set the multi-threshold detection alarm unit (1001) to each voltage level in sequence. At each voltage level, adjust the resistance value of the adjustable standard resistance box (200) to the nominal insulation resistance value corresponding to each voltage level. Use the high-precision current sensor (400) to measure the current value at this time. Repeat the measurement n times at each voltage level. Take the arithmetic mean of the current values ​​measured n times and calibrate the current parameter according to formula (3) to obtain the relative error of the current indication of the insulation coating detector (100) at the i-th voltage level. （3）； In the formula: —The arithmetic mean of the loop current values ​​measured n times at the i-th voltage level by the high-precision current sensor (400), i=1,2,3,...,mA; —The loop current value measured by the high-precision current sensor (400) at the i-th voltage level for the j-th time, in mA; —The relative error of the current reading of the insulation coating tester (100) at the i-th voltage level, mA; n — the number of times the high-precision current sensor (400) measures the current at each voltage level, n≥10.

6. A method for evaluating the uncertainty of resistance measurement results using a calibration device for a port machinery insulation coating tester according to any one of claims 1 to 4, characterized in that: The method for evaluating the uncertainty of resistance measurement results includes the following steps performed in sequence: b001: Establish the uncertainty evaluation model for resistance measurement results according to formula (4): （4）； In the formula: —The relative error of the resistance reading of the insulation coating tester (100), in Ω; —The nominal resistance value of the insulation coating tester (100), in Ω; —The reading of the adjustable standard resistance box (200), in Ω; —The change in resistance value caused by ambient temperature and humidity, in Ω; b002: Based on the above uncertainty evaluation model for resistance measurement results, the propagation rate is calculated according to formula (5), and the sensitivity coefficient is calculated according to formula (6): （5）； ， ， （6）； b003: A certain voltage in the multi-threshold detection alarm unit (1001) At the specified voltage level, based on the nominal insulation resistance value corresponding to the insulation coating tester (100) at that voltage level, the resistance value of the adjustable standard resistance box (200) is gradually reduced from 1.2 times the nominal insulation resistance value corresponding to the voltage level. As the resistance value decreases, the loop current measured by the high-precision current sensor (400) gradually increases. When the multi-threshold detection alarm unit (1001) starts to alarm, the resistance value of the adjustable standard resistance box (200) is recorded, and the arithmetic mean of n measured resistance values ​​is taken as the actual threshold resistance value output by the insulation coating tester (100). Then, the measurement uncertainty introduced by the adjustable standard resistance box (200) is calculated according to formula (7). : （7）； b004: The resistance parameter calibration device is the adjustable standard resistance box (200). The measurement uncertainty introduced by the adjustable standard resistance box (200) is evaluated using a type B method. If the maximum permissible error of the adjustable standard resistance box (200) within the nominal insulation resistance value range corresponding to this voltage range is a, then the half-width is a / 2. It is estimated that it is uniformly distributed. The measurement uncertainty introduced by the adjustable standard resistance box (200) is calculated according to formula (8). : （8）； b005: The entire calibration process is conducted in a temperature and humidity-controlled laboratory environment. The change in resistance caused by ambient temperature and humidity is negligible. ; b006: Due to the nominal resistance value of the insulation coating tester (100) The reading of the adjustable standard resistance box (200) Based on equations (5) to (8) above, the combined standard uncertainty of the resistance parameter measurement results of the insulation coating tester (100) is calculated according to formula (9). : （9）； b007: Taking the coverage factor k=2, based on the above combined standard uncertainty... The expanded uncertainty of the resistance parameter measurement result of the insulation coating tester (100) is calculated according to formula (10): （10）。

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