Contact box anti-condensation capacity evaluation method considering wet electric combination

Abstract

The application provides a contact box anti-condensation capacity evaluation method considering wet electricity combination, comprising building a contact box anti-condensation capacity evaluation platform considering wet electricity combination. The working current of the contact box during work is output by a working power simulator, the relative humidity of the evaluation device box is changed by a humidity control spray head, the limit voltage under different relative humidities is obtained, the limit voltage value is used to optimize the limit voltage reference value by an optimization algorithm, and then the anti-condensation capacity of the contact box is evaluated in combination with the limit voltage reference value. The application has the beneficial effect of providing a contact box anti-condensation capacity evaluation method considering wet electricity combination, building an evaluation platform, being able to simulate the wet electricity environment of the contact box work, providing a supplement for the insulation component performance evaluation technology, and being helpful to improve the safety of the switching equipment in the power transmission and distribution system and guarantee the power supply quality.

Description

A method for evaluating the anti-condensation capability of contact boxes considering wet electrical circuits Technical Field

[0001] This invention belongs to the technical field of insulation component performance evaluation, and in particular, it is a method for evaluating the anti-condensation capability of contact boxes considering wet electrical conditions. Background Technology

[0002] Switchgear, with its small footprint and high reliability and safety, constitutes a significant proportion of switchgear in power systems. Under high humidity conditions, condensation can occur on the surface of the contact boxes within the switchgear. Due to the difference in dielectric properties between the material itself and water, this severely affects the electric field distribution of the equipment, leading to a decrease in the insulation performance of the contact boxes, potentially causing breakdown, shortening the lifespan of electrical equipment, and even endangering personnel safety. Therefore, developing a method for evaluating the anti-condensation capability of contact boxes that considers both wet and dry conditions is of great importance.

[0003] The working environment of contact boxes is quite complex. Under different humidity conditions, their anti-condensation ability cannot be determined through preventive testing. At present, domestic and foreign research on insulation condensation phenomenon is mainly limited to the development process and hazards of condensation, lacking the assessment of the anti-condensation ability of insulation components, and even more so lacking the evaluation method for the anti-condensation ability of contact boxes under wet and dry conditions. Therefore, there is an urgent need for a test platform and method to evaluate the anti-condensation ability of contact boxes in the context of wet and dry conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a method for evaluating the anti-condensation capability of contact boxes that takes into account wet electrical connections.

[0005] The technical solution for achieving the objective of this invention is as follows:

[0006] A testing platform for the anti-condensation capability of contact boxes considering wet electrical circuits, the platform comprising:

[0007] Main control unit, working power controller, working power simulator, switch, high voltage measuring instrument, evaluation device box, contact box sample, humidity control nozzle, nozzle control unit, light quantity counter, light quantity recorder, grounding device one, grounding device two, grounding device three, humidity assessment instrument, signal transmitter, signal receiver, contact box electrodes;

[0008] The input terminal of the working power supply simulator is connected to the main control unit via the working power supply controller. The main control unit includes a signal receiver. The output terminal of the working power supply simulator is connected to the input terminal of the high voltage measuring device via a switch. The high voltage measuring device includes a signal transmitter. The input terminal of the high voltage measuring device is also connected to the input terminal of the contact box electrode.

[0009] The testing device box includes a contact box sample, a contact box electrode, a humidity control nozzle, a light quantity recorder, and a humidity evaluator. The humidity control nozzle and the humidity evaluator are respectively connected to the main control unit through the nozzle control unit, and the light quantity recorder is connected to the main control unit through the light quantity counter.

[0010] The working power supply simulator, high voltage measuring instrument, and contact box test sample are respectively connected to grounding device one, grounding device two, and grounding device three;

[0011] The evaluation methods of the aforementioned evaluation platform include the following steps:

[0012] S1: The relative humidity of the testing device box (6) is set to W0 on the main control unit (1). At the same time, the main control unit (1) sends a humidity setting signal to the nozzle control unit (9). The nozzle control unit (9) opens the humidity control nozzle (8). The humidity control nozzle (8) sprays water into the testing device box (6) to adjust the relative humidity inside the testing device box (6). The humidity evaluator (13) measures the relative humidity inside the testing device box (6) every t0 seconds and transmits the result to the nozzle control unit (9). The nozzle control unit (9) calculates the average value W of the two consecutive measurements. i If W i If the absolute error with W0 is less than ΔW, then W... i The signal is sent back to the main control unit (1), and the humidity control nozzle (8) is turned off at the same time;

[0013] S2: Take the following steps to measure the limit voltage of the contact box sample (7):

[0014] 1) Working power controller (2) Controlling the working power simulator (3) In [I S1 ,I S2 The range generates the operating current I. S ;

[0015] 2) High voltage measuring instrument (5) measures different operating currents I S The response voltage U that the test specimen (7) in the lower contact box withstands Bi And remember I S equals I S2 The response voltage at that time is U BM Different response voltages U are transmitted through the signal transmitter (14). Bi The signal is transmitted to the signal receiver (15) and recorded by the central control unit (1);

[0016] 3) Photometric recorder (11) measures different operating currents I S The light intensity of the sample (7) on the lower contact box is measured and the light intensity value Lni is obtained by the light intensity counter (10). The light intensity counter (10) transmits different light intensity values ​​Lni to the main control unit (1).

[0017] 4) The main control unit (1) will U Bi Plot a curve with U as the x-axis and Lni as the y-axis, when x equals U. BM When the curve is perpendicular to the x-axis, the intersection of the tangent line and the x-axis is taken as the limit voltage U. L ;

[0018] S3: Take values ​​uniformly at intervals of |W0-7W0| / (m-1) within the relative humidity range W0 to 7W0, and change the relative humidity inside the testing device box (6) set on the main control unit (1). Repeat S1 and S2 to obtain m sets of limit voltages U. L data;

[0019] S4: Calculate the reference value U of the limit voltage of the contact box sample (7) under different relative humidities W using the following formula. P :

[0020]

[0021] In equation (1), I S2 This is the maximum operating current, measured in amperes (A) and kilometres (U). P It is the limit voltage reference value, in kV; W is the relative humidity, in %RH; a is the error coefficient; b is the integral variable.

[0022] S5: The following algorithm is used to optimize and model formula (1) to obtain the value of a0 that minimizes the error. The specific steps are as follows:

[0023] 1) Randomly generate an initial solution a, and calculate the objective function f(a):

[0024]

[0025] In the formula, f(a) represents the objective function, m is the number of corresponding measured data sets, and U Pn U is the reference value of the limit voltage calculated after the nth measurement. Ln Let be the limit voltage for the nth measurement;

[0026] 2) Generate a new perturbation solution a', and calculate the objective function Δf = f(a) - f(a'); if Δf ≥ 0, accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion.

[0027] 3) Determine if the number of iterations has been reached. If it has, proceed to step 4; otherwise, proceed to step 2.

[0028] 4) Determine if the termination condition is met. If it is, the operation ends and the optimal solution is returned. Otherwise, reset the iteration count and proceed to step 2.

[0029] 5) Substituting the optimal value a0 obtained from the optimization into the following formula (3), we obtain the optimized formula for calculating the reference value of the limit voltage:

[0030]

[0031] In equation (3), U P ' is the optimized limit voltage reference value, and a0 is the optimized error coefficient;

[0032] S6: Calculate the anti-condensation capability evaluation factor α of the contact box considering wet electrical connection:

[0033]

[0034] In formula (4), α is the anti-condensation ability evaluation factor of the contact box, U P 'This is the optimized limit voltage reference value;

[0035] S7: Based on the anti-condensation capability evaluation factor α obtained from the above steps, evaluate the contact box. When α∈[0.8, +∞), it indicates that the anti-condensation capability of the contact box is very high and no further inspection is required; when α∈(0.5, 0.8), it indicates that the anti-condensation capability of the contact box has dropped to a certain level and maintenance needs to be arranged; when α∈(-∞, 0.5), it indicates that the anti-condensation capability of the contact box is very poor and it needs to be replaced immediately.

[0036] The beneficial effects of this invention are as follows:

[0037] (1) By building a test method for the anti-condensation capability of contact boxes that takes into account the combination of wet and electrical factors, the complex operation process with different wet and electrical parameters in the working environment of the contact boxes can be taken into account.

[0038] (2) The test device can control the humidity of the working environment of the contact box, which is beneficial to measure the electrical parameters of the contact box under different humidity conditions and further evaluate the anti-condensation ability.

[0039] (3) The operation steps of the evaluation platform are simple and clear, with the prospect of widespread adoption. It can also be modified according to the needs of different equipment evaluation, and has portability. Attached Figure Description

[0040] Figure 1 is a schematic diagram of the overall structure of the present invention; Detailed Implementation

[0041] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. A specific embodiment of a method for evaluating the anti-condensation capability of a contact box considering wet electrical coupling includes the following steps:

[0042] As shown in Figure 1, a contact box anti-condensation capability evaluation platform considering wet-electricity combination includes:

[0043] The main control unit (1), working power controller (2), working power simulator (3), switch (4), high voltage measuring instrument (5), evaluation device box (6), contact box sample (7), humidity control nozzle (8), nozzle control unit (9), light quantity counter (10), light quantity recorder (11), grounding device one (121), grounding device two (122), grounding device three (123), humidity evaluator (13), signal transmitter (14), signal receiver (15), contact box electrode (16);

[0044] The input terminal of the working power simulator (3) is connected to the main control unit (1) via the working power controller (2). The main control unit (1) includes a signal receiver (15). The output terminal of the working power simulator (3) is connected to the input terminal of the high voltage measuring device (5) via a switch (4). The high voltage measuring device (5) includes a signal transmitter (14). The input terminal of the high voltage measuring device (5) is also connected to the input terminal of the contact box electrode (16).

[0045] The testing device box (6) includes a contact box sample (7), a contact box electrode (16), a humidity control nozzle (8), a light quantity recorder (11), and a humidity evaluator (13). The humidity control nozzle (8) and the humidity evaluator (13) are respectively connected to the main control unit (1) through the nozzle control unit (9), and the light quantity recorder (11) is connected to the main control unit (1) through the light quantity counter (10).

[0046] The working power supply simulator (3), high voltage measuring device (5), and contact box test sample (7) are respectively connected to grounding device one (121), grounding device two (122), and grounding device three (123);

[0047] The evaluation methods of the aforementioned evaluation platform include the following steps:

[0048] S1: The relative humidity of the testing device box (6) is set to W0 on the main control unit (1). At the same time, the main control unit (1) sends a humidity setting signal to the nozzle control unit (9). The nozzle control unit (9) opens the humidity control nozzle (8). The humidity control nozzle (8) sprays water into the testing device box (6) to adjust the relative humidity inside the testing device box (6). The humidity evaluator (13) measures the relative humidity inside the testing device box (6) every t0 seconds and transmits the result to the nozzle control unit (9). The nozzle control unit (9) calculates the average value W of the two consecutive measurements. i If W i If the absolute error with W0 is less than ΔW, then W... i The signal is sent back to the main control unit (1), and the humidity control nozzle (8) is turned off at the same time;

[0049] S2: Take the following steps to measure the limit voltage of the contact box sample (7):

[0050] 1) Working power controller (2) Controlling the working power simulator (3) In [I S1 ,I S2 The range generates the operating current I. S ;

[0051] 2) High voltage measuring instrument (5) measures different operating currents I S The response voltage U that the test specimen (7) in the lower contact box withstands Bi And remember I S equals I S2 The response voltage at that time is U BM Different response voltages U are transmitted through the signal transmitter (14). Bi The signal is transmitted to the signal receiver (15) and recorded by the central control unit (1);

[0052] 3) Photometric recorder (11) measures different operating currents I S The light intensity of the sample (7) on the lower contact box is measured and the light intensity value Lni is obtained by the light intensity counter (10). The light intensity counter (10) transmits different light intensity values ​​Lni to the main control unit (1).

[0053] 4) The main control unit (1) will U Bi Plot a curve with U as the x-axis and Lni as the y-axis, when x equals U. BM When the curve is perpendicular to the x-axis, the intersection of the tangent line and the x-axis is taken as the limit voltage U. L ;

[0054] S3: Take values ​​uniformly at intervals of |W0-7W0| / (m-1) within the relative humidity range W0 to 7W0, and change the relative humidity inside the testing device box (6) set on the main control unit (1). Repeat S1 and S2 to obtain m sets of limit voltages U. L data;

[0055] S4: Calculate the reference value U of the limit voltage of the contact box sample (7) under different relative humidities W using the following formula. P :

[0056]

[0057] In equation (1), I S2 This is the maximum operating current, measured in amperes (A) and kilometres (U). P It is the limit voltage reference value, in kV; W is the relative humidity, in %RH; a is the error coefficient; b is the integral variable.

[0058] S5: The following algorithm is used to optimize and model formula (1) to obtain the value of a0 that minimizes the error. The specific steps are as follows:

[0059] 1) Randomly generate an initial solution a, and calculate the objective function f(a):

[0060]

[0061] In the formula, f(a) represents the objective function, m is the number of corresponding measured data sets, and U Pn U is the reference value of the limit voltage calculated after the nth measurement. Ln Let be the limit voltage for the nth measurement;

[0062] 2) Generate a new perturbation solution a', and calculate the objective function Δf = f(a) - f(a'); if Δf ≥ 0, accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion.

[0063] 3) Determine if the number of iterations has been reached. If it has, proceed to step 4; otherwise, proceed to step 2.

[0064] 4) Determine if the termination condition is met. If it is, the operation ends and the optimal solution is returned. Otherwise, reset the iteration count and proceed to step 2.

[0065] 5) Substituting the optimal value a0 obtained from the optimization into the following formula (3), we obtain the optimized formula for calculating the reference value of the limit voltage:

[0066]

[0067] In equation (3), U P ' is the optimized limit voltage reference value, and a0 is the optimized error coefficient;

[0068] S6: Calculate the anti-condensation capability evaluation factor α of the contact box considering wet electrical connection:

[0069]

[0070] In formula (4), α is the anti-condensation ability evaluation factor of the contact box, U P 'This is the optimized limit voltage reference value;

[0071] S7: Based on the anti-condensation capability evaluation factor α obtained from the above steps, evaluate the contact box. When α∈[0.8, +∞), it indicates that the anti-condensation capability of the contact box is very high and no further inspection is required; when α∈(0.5, 0.8), it indicates that the anti-condensation capability of the contact box has dropped to a certain level and maintenance needs to be arranged; when α∈(-∞, 0.5), it indicates that the anti-condensation capability of the contact box is very poor and it needs to be replaced immediately.

Claims

1. A method for evaluating the anti-condensation capability of contact boxes considering combined wet and dry conditions, characterized in that, First, a test platform for the anti-condensation capability of the contact box considering wet and electrical integration was constructed. The platform includes: a central control unit (1), a working power controller (2), a working power simulator (3), a switch (4), a high voltage measuring instrument (5), a test device box (6), a contact box sample (7), a humidity control nozzle (8), a nozzle control unit (9), a light quantity counter (10), a light quantity recorder (11), grounding device one (121), grounding device two (122), grounding device three (123), a humidity evaluator (13), a signal transmitter (14), and a signal receiver. The test device box (6) contains a receiver (15) and contact box electrodes (16). The input terminal of the power supply simulator (3) is connected to the main control unit (1) via the power supply controller (2). The main control unit (1) includes a signal receiver (15). The output terminal of the power supply simulator (3) is connected to the input terminal of the high voltage measuring device (5) via a switch (4). The high voltage measuring device (5) includes a signal transmitter (14). The input terminal of the high voltage measuring device (5) is also connected to the input terminal of the contact box electrodes (16). The test device box (6) contains a contact box sample (7) and contact box electrodes (16). The system includes a humidity control nozzle (8), a light quantity recorder (11), and a humidity evaluator (13). The humidity control nozzle (8) and the humidity evaluator (13) are connected to the main control unit (1) via the nozzle control unit (9), and the light quantity recorder (11) is connected to the main control unit (1) via the light quantity counter (10). The working power supply simulator (3), the high voltage measuring device (5), and the contact box sample (7) are connected to grounding device one (121), grounding device two (122), and grounding device three (123), respectively. The evaluation method of the above evaluation platform includes the following steps: S 1: Set the relative humidity of the testing device box (6) to W0 on the main control unit (1). At the same time, the main control unit (1) sends a humidity setting signal to the nozzle control unit (9). The nozzle control unit (9) opens the humidity control nozzle (8). The humidity control nozzle (8) sprays water into the testing device box (6) to adjust the relative humidity inside the testing device box (6). The humidity evaluator (13) measures the relative humidity inside the testing device box (6) every t0 seconds and transmits the result to the nozzle control unit (9). The nozzle control unit (9) calculates the average value W of the two consecutive measurements. i If W i If the absolute error with W0 is less than ΔW, then W... i The signal is sent back to the main control unit (1), and the humidity control nozzle (8) is turned off at the same time; S2: The following steps are taken to measure the limit voltage of the contact box sample (7): 1) The working power controller (2) controls the working power simulator (3) in [I S1 ,I S2 The range generates the operating current I. S ;2) High voltage measuring instrument (5) measures different operating currents I S The response voltage U that the test specimen (7) in the lower contact box withstands Bi And remember I S equals I S2 The response voltage at that time is U BM Different response voltages U are transmitted through the signal transmitter (14). Bi The signal is transmitted to the signal receiver (15) and recorded by the main control unit (1); 3) The light recorder (11) measures different operating currents I S The light intensity of the sample (7) on the lower contact box is measured and the light intensity value Lni is obtained by the light intensity counter (10). The light intensity counter (10) transmits different light intensity values ​​Lni to the main control unit (1); 4) The main control unit (1) transmits U Bi Plot a curve with U as the x-axis and Lni as the y-axis, when x equals U. BM When the curve is perpendicular to the x-axis, the intersection of the perpendicular line and the x-axis is taken as the limit voltage U. L S3: Take values ​​uniformly at intervals of |W0-7W0| / (m-1) within the relative humidity range W0 to 7W0, and change the relative humidity inside the testing device box (6) set on the main control unit (1). Repeat S1 and S2 to obtain m sets of limit voltages U. L Data; S4: Calculate the reference value U of the limit voltage of the contact box sample (7) under different relative humidities W using the following formula. P : (1) In equation (1), I S2 This is the maximum operating current, measured in amperes (A) and kilometres (U). P It is the limit voltage reference value, in kV; W is the relative humidity, in %RH; a is the error coefficient; b is the integral variable; S5: The following algorithm is used to optimize and model formula (1) to obtain the value of a0 that minimizes the error. The specific steps are: 1) Randomly generate the initial solution a and calculate the objective function f(a): (2) In the formula, f(a) represents the objective function, m is the number of corresponding measured data sets, and U Pn U is the reference value of the limit voltage calculated after the nth measurement. Ln 1) The limit voltage for the nth measurement; 2) Generate a new perturbation solution a' and calculate the objective function. ;like If the new solution is accepted, then accept the new solution; otherwise, obtain the new solution according to the probability acceptance criterion. 3) Determine whether the iteration count has been reached. If it has, proceed to step 4; otherwise, proceed to step 2. 4) Determine whether the termination condition is met. If it is met, the operation ends and the optimal solution is returned; otherwise, reset the iteration count and proceed to step 2. 5) Substitute the optimal value a0 obtained from the optimization into the following formula (3) to obtain the optimized limit voltage reference value calculation formula: In equation (3), U P This is the optimized limit voltage reference value, and a0 is the optimized error coefficient; S6: Calculate the anti-condensation capability evaluation factor α of the contact box considering wet and dry conditions. In equation (4), α is the anti-condensation ability evaluation factor of the contact box, U P S7: Based on the contact box anti-condensation capability evaluation factor α obtained from the above steps, the anti-condensation capability of the contact box is evaluated. When α∈[0.8, +∞), it indicates that the anti-condensation capability of the contact box is very high and no further inspection is required. When α∈(0.5, 0.8), it indicates that the anti-condensation capability of the contact box has dropped to a certain level and maintenance needs to be arranged. When α∈(-∞, 0.5), it indicates that the anti-condensation capability of the contact box is very poor and it needs to be replaced immediately.

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