A method for judging anti-corona applied to a single-phase power frequency power supply

Abstract

The present application relates to the technical field of electric dust removal, and particularly relates to a reverse corona judgment method applied to a single-phase power frequency power supply, which comprises the following steps: sampling a secondary current value of an electric dust remover, if the current secondary current value meets a first preset condition, sampling three groups of secondary current values and secondary voltage values; if whether the three groups of secondary current values meet a second preset condition, calculating a ratio between the secondary current value and the corresponding secondary voltage value in at least two groups; if the ratio is greater than a preset ratio, determining that a reverse corona phenomenon occurs, and recording the first value in the three groups of secondary current values as a control point; starting a timer, and after the timer reaches, executing the next round of reverse corona phenomenon judgment program. The present application does not need to repeatedly draw a volt-ampere curve to judge the reverse corona, can realize real-time detection and control, automatically saves the control point if an interruption event occurs, and automatically restores to the control point after the interruption event ends.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric dust removal, in particular to a reverse corona judgment method applied to a single-phase power frequency power supply. BACKGROUND

[0002] The reverse corona phenomenon is a unique phenomenon that seriously affects the dust removal efficiency of an electric dust remover in the operation of the electric dust removal, and is specifically manifested in the sharp rise of the secondary current and the invariability of the secondary voltage from the secondary parameter. In the past, the reverse corona is mainly judged by whether the reverse corona occurs and the reverse corona point through the voltage-current curve characteristic analysis. However, no matter how fast the voltage-current curve is controlled, it needs to take values at different voltage and current points for drawing, and if the drawing points are too few, the voltage-current characteristic curve cannot be correctly fitted, and if the drawing points are too many, too much time will be wasted.

[0003] The biggest problem of judging the reverse corona through the voltage-current curve is that 1: the voltage-current curve needs to record the parameters from low to high or from high to low, which will inevitably lead to the voltage reduction process in the device operation, affecting the normal operation of the device. 2: The voltage-current curve drawing is easy to be interrupted, for example, in the process of drawing the voltage-current curve, the external voltage reduction vibration signal input cannot continue the current sampling process. 3: The voltage-current curve control process is complex, the calculation amount is large, and the error is high. SUMMARY

[0004] Therefore, the present application provides a reverse corona judgment method applied to a single-phase power frequency power supply, which does not need to repeatedly draw the voltage-current curve to judge the reverse corona, can realize real-time detection and control, and can automatically save the control point if an interruption event occurs and automatically restore to the control point after the interruption event ends.

[0005] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0006] A reverse corona judgment method applied to a single-phase power frequency power supply, comprising the following steps:

[0007] S1, starting the reverse corona phenomenon judgment program, sampling the secondary current value of the electric dust remover, judging whether the current secondary current value meets the first preset condition, if yes, sampling three groups of secondary current values and secondary voltage values, and executing S2; otherwise, ending the current reverse corona phenomenon judgment program and waiting for the start of the next reverse corona phenomenon judgment program;

[0008] S2, judging whether the three groups of sampled secondary current values meet the second preset condition, if yes, calculating the ratio between the secondary current value and the corresponding secondary voltage value of at least two groups, and executing S3; otherwise, ending the current reverse corona phenomenon judgment program and waiting for the start of the next reverse corona phenomenon judgment program;

[0009] S3, judging whether the ratio is greater than a preset ratio, if yes, determining that the reverse corona phenomenon occurs, recording a first value of the three recorded secondary currents as a control point, and performing S4; otherwise, determining that the reverse corona phenomenon does not occur, ending the reverse corona phenomenon judgment procedure, and waiting for the start of the next round of reverse corona phenomenon judgment procedure;

[0010] S4, starting a timer, and after the timer expires, performing the next round of reverse corona phenomenon judgment procedure.

[0011] Further, the first preset condition in S1 is that the current secondary current value is greater than 10% of the rated value.

[0012] Further, the second preset condition in S2 is that the difference between the adjacent two of the three continuously sampled secondary current values continuously increases by 100mA.

[0013] Further, the preset ratio in S3 is 4 or 5, which is set according to engineering experience.

[0014] Further, in S3, when the reverse corona phenomenon is determined to occur, the reverse corona count value is increased by 1, and the reverse corona flag is set to 1; when the reverse corona phenomenon is determined not to occur, the reverse corona count value is cleared to 0, and the reverse corona flag is set to 0.

[0015] Further, in S3, after recording the first value of the three recorded secondary currents as a control point, a reverse corona phenomenon elimination instruction is triggered to the related control device, the electrostatic precipitator is controlled to exit the current control state, and the reverse corona phenomenon elimination processing is performed on the electrostatic precipitator.

[0016] Further, the reverse corona phenomenon elimination processing performed on the electrostatic precipitator is: voltage reduction, dust cleaning or rapping.

[0017] Further, in S4, a two-minute timer is started, and after the timer expires, the electrostatic precipitator is controlled to enter a new round of control state, and the control point recorded in the last round is used as the initial output current of the new round of control state.

[0018] Further, if the control point recorded in the last round is used as the initial output current of the new round of control state, and the reverse corona phenomenon continuously occurs, the control point current is reduced.

[0019] According to the above technical solution, compared with the prior art, the present application has the following beneficial effects:

[0020] This invention automatically calculates and selects the control operating point by monitoring the changes in secondary voltage and secondary current in real time during normal operation of the power frequency power supply, eliminating the need to repeatedly draw volt-ampere curves to determine back corona. No voltage reduction is required during operation, thus not affecting the dust collector's dust removal efficiency. It enables real-time detection and control with minimal computation and a simple control process. If an interruption event occurs, the control point output current is automatically saved, and it automatically restores to the control point output current after the interruption event ends. It boasts a high degree of automation and high detection accuracy. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0022] Fig. 1 A flowchart of the anti-corona determination method provided by the present invention;

[0023] Fig. 2 A detailed flowchart of the anti-corona discharge determination method provided by the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figs. 1-2 As shown in the figure, this invention discloses a method for determining back corona applied to single-phase power frequency power supplies, including the following steps:

[0026] S1. Start the back corona phenomenon judgment program, sample the secondary current value of the electrostatic precipitator, and determine whether the current secondary current value meets the first preset condition. If so, sample three sets of secondary current values ​​and secondary voltage values, and execute S2; otherwise, end the current round of back corona phenomenon judgment program and wait for the start of the next round of back corona phenomenon judgment program.

[0027] S2. Determine whether the three sets of sampled secondary current values ​​meet the second preset condition. If so, calculate the ratio between the secondary current value and its corresponding secondary voltage value in at least two sets, and execute S3. Otherwise, end the current round of back corona phenomenon judgment program and wait for the start of the next round of back corona phenomenon judgment program.

[0028] S3, judging whether the ratio is greater than a preset ratio, if yes, determining that the reverse corona phenomenon occurs, recording a first value of the three recorded secondary currents as a control point, and performing S4; otherwise, determining that the reverse corona phenomenon does not occur, ending the reverse corona phenomenon judgment procedure, and waiting for the start of the next round of reverse corona phenomenon judgment procedure;

[0029] S4, starting a timer, after timing, returning to S1 to perform the next round of reverse corona phenomenon judgment procedure, or no longer judging whether the current secondary current value meets the first preset condition, only performing sampling of the three groups of secondary current values and secondary voltage values in S1, and subsequent S2-S4.

[0030] In a preferred embodiment, the first preset condition in S1 is that the current secondary current value is greater than 10% of the rated value. Only when the current secondary current value is greater than 10% of the rated value, the subsequent reverse corona phenomenon judgment is performed, otherwise the reverse corona phenomenon judgment is not performed. If the current secondary current value is less than 10% of the rated value, false judgment is easy to occur.

[0031] Meanwhile, the second preset condition in S2 is that the difference between the adjacent two groups of secondary current values in the three continuously sampled groups of secondary current values continuously increases by 100mA.

[0032] The electric dust collector is in current control mode, and in the embodiment of the present application, 100mA is taken as a control interval. If the secondary current continuously increases by 100mA, such as 300mA, 400mA, and 500mA, in the three groups of data in the three continuously sampled secondary currents and secondary voltages, at this time, it is judged that the second preset condition is met, and the subsequent S3 judgment is continued.

[0033] The preset ratio di / dv (i.e. the slope) between a group of secondary current and secondary voltage in S3 is 4 or 5, which is set according to engineering experience in combination with the operation data of previous projects. In the embodiment, at least two ratios of the three groups of data are taken for judgment, and preferably three groups of data are taken.

[0034] In a specific embodiment, after recording the first value of the three recorded secondary currents as a control point in S3, a reverse corona phenomenon elimination instruction is triggered to the related control device, the electric dust collector is controlled to exit the current control state, and the reverse corona phenomenon elimination processing is performed on the electric dust collector.

[0035] The reverse corona phenomenon elimination processing performed on the electric dust collector is voltage reduction, dust cleaning or rapping. The reverse corona phenomenon elimination processing can be taken as an interrupt event. When the electric dust collector occurs the reverse corona phenomenon, the current control state is exited, and the reverse corona control point of the current round is automatically saved. After the interrupt event ends, the control point is automatically restored.

[0036] In one embodiment, in S3, when it is determined that the back corona phenomenon occurs, the back corona count value is added by 1, and the back corona flag is set to 1; when it is determined that the back corona phenomenon does not occur, the back corona count value is cleared to 0, and the back corona flag is set to 0. In this embodiment, after the interrupt event occurs, when a new round of back corona phenomenon judgment program is executed, if it is determined again that the back corona phenomenon exists, the number of back corona occurrences is accumulated on the basis of the previous one, so that the staff can be reminded that the back corona of the dust collector continues to occur, so as to take further processing measures. If the back corona phenomenon does not exist after the interrupt event occurs, the back corona count is cleared, which indicates that the dust collector is running normally.

[0037] Meanwhile, in this embodiment, whether the back corona exists or not is indicated by "0" or "1", which can enable the staff to intuitively understand the state of the dust collector.

[0038] In other embodiments, in S4, a two-minute timer is started, and after the timer reaches, the dust collector is controlled to enter a new round of control state, and the control point recorded in the previous round is taken as the initial output current of the new round of control state.

[0039] After the timing time reaches, it is necessary to increase the current again to detect, and it is necessary to take the control point to the initial position in the three groups of parameters. If the control point is not at the initial position, the control point current will continuously increase, and the requirement of back corona control cannot be met. For example, in the three groups of data of 300mA, 400mA and 500mA sampled in the previous round, 300mA is taken as the output current of the control point in the new round when the back corona phenomenon judgment program is executed.

[0040] If the control point recorded in the previous round is taken as the initial output current of the new round of control state, the back corona phenomenon occurs continuously, and the control point current is reduced. Since the back corona phenomenon is not a continuous fault state, it can be restored to a normal state by itself through dust cleaning, voltage reduction and other methods, so if the back corona phenomenon is detected continuously, it means that the current control point is too high, and at this time the output current needs to be reduced, which can be reduced by 100mA on the basis of the last time. Because the control mode of the electric dust collector is current control, the current is increased by 100mA each time, so the control gear is 100mA.

[0041] The control point of the back corona is actually judged by the inflection point of the VI curve, that is, the current increases a lot or sharply in the case of small voltage change. This state can be restored to a normal state by itself by reducing the output power of the power supply or stopping the output of the power supply for a period of time, so when the current control is reduced and the back corona phenomenon still occurs after re-detection, it means that the output power of the control point is too high to eliminate the back corona, so the control current needs to be reduced again.

[0042] The so-called continuous reverse corona refers to the case that the reverse corona is judged in two continuous control periods, for example, the reverse corona is judged in the range of 1000mA-1200mA, the control point is controlled at 1000mA, the control of 1000mA is performed for two minutes, and then the detection is performed again, if the reverse corona still exists, the control current is reduced to 1000mA-100mA=900mA.

[0043] The various embodiments are described in the specification by way of progression, each building on the last to facilitate ease of understanding. The embodiments are related to each other and each embodiment builds upon all previous embodiments. Therefore, some of the disclosure of the previous embodiments is incorporated by reference into the disclosure found here, for example, that a similar mechanism can be employed for any other embodiments described herein. The disclosure herein also contemplates combinations of the disclosed embodiments with each other as well as combinations of the disclosed embodiments with method steps found elsewhere.

[0044] The above description of disclosed embodiments is intended to be illustrative and not restrictive. Many embodiments will be apparent to those of skill in the art upon reading the above description. The scope of the application should, therefore, be determined not with reference to the above description, but instead with reference to the appended claims, along with their full scope of equivalents. Numerous modifications and variations are possible in light of the above disclosures. For example, while specific embodiments have been exemplified here, other variations and modifications can be employed. It is intended that the present disclosure encompass such variations and modifications as fall within the scope of the appended claims.

Claims

1. A method for determining back corona discharge in a single-phase power frequency power supply, characterized in that, Includes the following steps: S1. Start the back corona phenomenon judgment program, sample the secondary current value of the electrostatic precipitator, and determine whether the current secondary current value meets the first preset condition. If so, sample three sets of secondary current values ​​and secondary voltage values, and execute S2; otherwise, end the current round of back corona phenomenon judgment program and wait for the start of the next round of back corona phenomenon judgment program. The first preset condition is: the current secondary current value is greater than 10% of the rated value; S2. Determine whether the three sets of sampled secondary current values ​​meet the second preset condition. If so, calculate the ratio between the secondary current value and its corresponding secondary voltage value in at least two sets, and execute S3. Otherwise, end the current round of back corona phenomenon judgment program and wait for the start of the next round of back corona phenomenon judgment program. The second preset condition is: in the three sets of continuously sampled secondary current values, the difference between two adjacent sets of secondary current values ​​increases by 100mA continuously. S3. Determine if the ratio is greater than the preset ratio. If yes, it is determined that a back corona phenomenon has occurred. Record the first value of the three sets of secondary currents as the control point and execute S4. Otherwise, it is determined that a back corona phenomenon has not occurred. End the current back corona phenomenon judgment procedure and wait for the start of the next back corona phenomenon judgment procedure. S4. Start the timer. After the timer expires, execute the next round of the anti-corona phenomenon judgment program.

2. The method for determining back corona applied to single-phase power frequency power supplies according to claim 1, characterized in that, The preset ratio in S3 is 4 or 5, which is set based on engineering experience.

3. The method for determining back corona applied to single-phase power frequency power supplies according to claim 1, characterized in that, In S3, when it is determined that a back corona phenomenon has occurred, the back corona count value is incremented by 1 and the back corona flag is set to 1; when it is determined that no back corona phenomenon has occurred, the back corona count value is cleared to 0 and the back corona flag is set to 0.

4. The method for determining back corona applied to single-phase power frequency power supplies according to claim 1, characterized in that, In S3, after recording the first value of the three sets of secondary currents as the control point, a back corona elimination command is triggered to the relevant control device, controlling the electrostatic precipitator to exit the current control state and performing back corona elimination processing on the precipitator.

5. The method for determining back corona applied to single-phase power frequency power supplies according to claim 4, characterized in that, The methods for eliminating the back corona phenomenon in electrostatic precipitators are: voltage reduction, dust removal, or vibration.

6. The method for determining back corona applied to single-phase power frequency power supplies according to claim 1, characterized in that, In S4, a two-minute timer is started. After the timer expires, the dust collector is controlled to enter a new round of control state, and the control point recorded in the previous round is used as the initial output current of the new round of control state.

7. The method for determining back corona applied to single-phase power frequency power supplies according to claim 6, characterized in that, If the control point recorded in the previous round is used as the initial output current for the new round of control, and the back corona phenomenon occurs continuously, then the control point current should be reduced.

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