A method for preventing mis-alarm monitoring of the temperature of switch contacts

Abstract

The present invention provides a method for preventing mis-alarm monitoring of the temperature of switch contacts, which includes calculating the real-time temperature rise data of each switch contact temperature point; collecting three-phase currents IA, IB, and IC, and calculating the power frequency effective values of their respective currents; determining whether the temperature rise of any point among each contact temperature point exceeds the temperature rise set value; if the judgment result is yes, calculating the first correlation coefficient between the temperature rise and the phase current according to the typical correlation coefficient calculation formula; calculating the second correlation coefficient between the first correlation coefficients according to the typical correlation coefficient calculation formula; when the temperature rise of N points exceeds the temperature rise set value, determining the alarm condition according to the second correlation coefficient, and when the alarm condition lasts for more than the alarm delay time, sending out an over-temperature alarm signal. Applying the present invention can avoid problems existing in the prior art, such as single set value, large influence of environmental factors, easy damage of components, and easy false alarm of alarms.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent monitoring of high-voltage side equipment, and particularly relates to a method for preventing mis-alarm monitoring of switch contact temperature. Background Art

[0002] There are a large number of medium and high-voltage switches with huge volumes, and their safe and stable operation is related to power supply safety and reliability.

[0003] The switch contacts usually have 6 points (for a three-phase switch, each phase has 2 contact points). The traditional monitoring method is: measure the contact temperatures of 6 points, and once the temperature of any point exceeds the set value, an alarm is given to notify the maintenance personnel to repair the circuit breaker switch. However, many problems are often faced:

[0004] 1. Single fixed value: Once the temperature exceeds this fixed value, an alarm is triggered. In order to ensure the sensitivity of the alarm, this fixed value is not too large. Then, once the current is large, false alarms often occur, resulting in an increase in the number of planned power outages and wasting a lot of manpower and material resources.

[0005] 2. Greatly affected by the environment: When the ambient temperature rises, the actual temperature is easily increased to near the fixed value, causing false alarms.

[0006] 3. The temperature sensor is in direct contact with the high-voltage switch contacts. The complex electric and magnetic fields and high-voltage environment cause the temperature sensor to be extremely vulnerable to damage; after damage, the collected temperature value becomes near the maximum or minimum value. When it is at the maximum value, it causes the temperature to exceed the limit value, resulting in false alarms. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for preventing mis-alarm monitoring of switch contact temperature, which can avoid problems such as single fixed value, large influence of environmental factors, easy damage of components, and easy false alarms existing in the prior art.

[0008] To solve the above problems, the technical solutions adopted by the present invention are as follows:

[0009] A method for preventing mis-alarm monitoring of switch contact temperature, the method comprising the following steps:

[0010] Calculate the real-time temperature rise data of each switch contact temperature point, which are ΔTA1, ΔTA2, ΔTB1, ΔTB2, ΔTC1, ΔTC2 respectively;

[0011] Collect three-phase currents IA, IB, IC, and calculate the power frequency effective values IA rms , IB rms , IC rms ;

[0012] Determine whether the temperature rise of any one of the contact temperature points exceeds the temperature rise set value ΔT set ;

[0013] If the judgment result is yes, according to the typical correlation coefficient calculation formula, calculate the first correlation coefficient P between the temperature rise and the phase current ΔTA1_IA , P ΔTA2_IA , P ΔTB1_IB , P ΔTB2_IB , P ΔTC1_IC , P ΔTC2_IC ;

[0014] According to the typical correlation coefficient calculation formula, calculate the correlation coefficient P ΔTA1_IA and P ΔTA2_IA between, P ΔTB1_IB and P ΔTB2_IB between and P ΔTC1_IC and P ΔTC2_IC the second correlation coefficient between

[0015] When the temperature rise of N points exceeds the temperature rise set value ΔT set , according to the second correlation coefficient determine the alarm condition. When this alarm condition lasts for more than the alarm delay time t set and then, send out an over-temperature alarm signal, where N≥1.

[0016] According to a method for preventing mis-alarm monitoring of switch contact temperature provided by the present invention, the calculating the real-time temperature rise data of each contact temperature point includes:

[0017] Obtain the temperatures of each switch contact TA1, TA2, TB1, TB2, TC1, TC2 and the ambient temperature Ty. Subtract the ambient temperature Ty from the temperatures of each switch contact to calculate the real-time temperature rise data of each contact temperature point, where when collecting the switch contact temperature, each contact has no less than one temperature collection point.

[0018] According to a method for preventing mis-alarm monitoring of switch contact temperature provided by the present invention, when the temperature rise data of only 1 temperature point exceeds the temperature rise set value ΔT set , taking ΔTA1 as an example, when ΔTA1 is greater than ΔT set , and is less than the first preset value, and is greater than the second preset value, start timing. When this alarm condition lasts for more than the alarm delay time t set and then, send out a 1-point over-temperature alarm signal.

[0019] A method for preventing false alarm monitoring of the temperature of a switch contact provided by the present invention. When the temperature rise data of two points exceeds the temperature rise set value ΔT set When this occurs, if the two temperature points are in the same phase, taking ΔTA1 and ΔTA2 as examples, that is, both ΔTA1 and ΔTA2 are greater than ΔT set , and After it is greater than the second preset value, start timing. When this alarm condition persists for more than the alarm delay time t set , a single-phase over-temperature alarm signal is issued.

[0020] A method for preventing false alarm monitoring of the temperature of a switch contact provided by the present invention. If the two temperature points are in different phases, taking ΔTA1 and ΔTB1 as examples, that is, both ΔTA1 and ΔTB1 are greater than ΔT set , and is less than the first preset value, is less than the first preset value, After it is greater than the second preset value, start timing. When this alarm condition persists for more than the alarm delay time t set , a two-point over-temperature alarm signal is issued.

[0021] A method for preventing false alarm monitoring of the temperature of a switch contact provided by the present invention. When the temperature rise data of three points exceeds the temperature rise set value ΔT set , when the three temperature points are in different phases, taking ΔTA1, ΔTB1, and ΔTC1 as examples, both ΔTA1, ΔTB1, and ΔTC1 are greater than ΔT set , and After they are all greater than the second preset value, start timing. When this alarm condition persists for more than the alarm delay time t set , a three-point over-temperature alarm signal is issued.

[0022] A method for preventing false alarm monitoring of the temperature of a switch contact provided by the present invention. After determining that the temperature rise data of three temperature points exceeds the temperature rise set value ΔT set , and when two of the temperature points are in the same phase, perform a two-point over-temperature judgment.

[0023] A method for preventing false alarm monitoring of the temperature of a switch contact provided by the present invention. When the temperature rise data of more than four temperature points exceeds the temperature rise set value ΔT set , perform a combined judgment according to the one-point, two-point, and three-point over-temperature judgments.

[0024] A method for preventing false alarm monitoring of the temperature of a switch contact provided by the present invention. The calculation formula of the typical correlation coefficient is expressed as formula (1):

[0025]

[0026] Among them, X1 and X2 represent the data for calculating the correlation coefficient required, ΔX1 and ΔX2 represent the differences between two sampling points before and after the data, k identifies the current sampling point time, and fs is the sampling frequency.

[0027] According to a method for preventing mis-alarm monitoring of the temperature of a switch contact provided by the present invention, the first preset value is 0.3, and the second preset value is 0.8.

[0028] Thus, compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention divides the temperature point determination methods for 1 point, 2 points, and 3 points. When more than 4 points and above, they can all be judged by the combination of 1, 2, and 3, and the number of identified points and accuracy are higher.

[0030] (2) In the monitoring process of the present invention, the temperature rise data and current data are combined, and on the basis of the combination, the calculation of the change process of the correlation between the temperature rise and the current is realized, and the correlation of the change process is judged. The timing process has the effect of trend accumulation, which not only ensures the accuracy of the alarm monitoring, but also can avoid the problem of easy false alarm in the reported alarm caused by the single temperature exceeding the limit or being too sensitive.

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Description of the Drawings

[0032] Figure 1 is a flowchart of an embodiment of a method for preventing mis-alarm monitoring of the temperature of a switch contact according to the present invention. Detailed Embodiments

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0034] See Figure 1 , the present invention provides a method for preventing mis-alarm monitoring of the temperature of a switch contact, which includes the following steps:

[0035] Step S1, calculate the real-time temperature rise data of each switch contact temperature point, which are ΔTA1, ΔTA2, ΔTB1, ΔTB2, ΔTC1, and ΔTC2 respectively.

[0036] Step S2, collect three-phase currents IA, IB, and IC, and calculate the power frequency effective values IA rms , IB rms,IC rms 。

[0037] Step S3, determine whether the temperature rise of any one of the contact temperature points exceeds the temperature rise set value ΔT set 。

[0038] Step S4, if the judgment result is yes, calculate the first correlation coefficient P between the temperature rise and the phase current according to the typical correlation coefficient calculation formula ΔTA1_IA ,P ΔTA2_IA ,P ΔTB1_IB ,P ΔTB2_IB ,P ΔTC1_IC ,P ΔTC2_IC 。

[0039] Step S5, calculate the correlation coefficient P according to the typical correlation coefficient calculation formula ΔTA1_IA between P ΔTA2_IA and P ΔTB1_IB between, P ΔTB2_IB and P ΔTC1_IC between, and P ΔTC2_IC the second correlation coefficient between

[0040] Step S6, when the temperature rise of N points exceeds the temperature rise set value ΔT set , determine the alarm condition according to the second correlation coefficient . When the alarm condition lasts for more than the alarm delay time t set , send out an over-temperature alarm signal, where N≥1.

[0041] In this embodiment, the calculation of the real-time temperature rise data of each contact temperature point includes:

[0042] Obtain the temperatures of each switch contact TA1, TA2, TB1, TB2, TC1, TC2 and the ambient temperature Ty. Subtract the ambient temperature Ty from the temperatures of each switch contact to calculate the real-time temperature rise data of each contact temperature point. Among them, when collecting the switch contact temperature, each contact has no less than one temperature collection point.

[0043] When the temperature rise data of only 1 temperature point exceeds the temperature rise set value ΔT set , taking ΔTA1 as an example, when ΔTA1 is greater than ΔT set , and is less than the first preset value, and is greater than the second preset value, start timing. When the alarm condition lasts for more than the alarm delay time t set , send out a 1-point over-temperature alarm signal.

[0044] When the temperature rise data of 2 points exceeds the temperature rise set value ΔT setWhen two temperature points are in the same phase, taking ΔTA1 and ΔTA2 as examples, that is, both ΔTA1 and ΔTA2 are greater than ΔT set , and start timing after being greater than the second preset value. When this alarm condition lasts for more than the alarm delay time t set , a single-phase overtemperature alarm signal is issued.

[0045] When two temperature points are in different phases, taking ΔTA1 and ΔTB1 as examples, that is, both ΔTA1 and ΔTB1 are greater than ΔT set , and is less than the first preset value, is less than the first preset value, start timing after being greater than the second preset value. When this alarm condition lasts for more than the alarm delay time t set , a two-point overtemperature alarm signal is issued.

[0046] When the temperature rise data of three points exceeds the temperature rise fixed value ΔT set , when the three temperature points are in different phases, taking ΔTA1, ΔTB1, and ΔTC1 as examples, both ΔTA1, ΔTB1, and ΔTC1 are greater than ΔT set , and start timing after both are greater than the second preset value. When this alarm condition lasts for more than the alarm delay time t set , a three-point overtemperature alarm signal is issued.

[0047] After determining that the temperature rise data of three temperature points exceeds the temperature rise fixed value ΔT set , and when two temperature points are in the same phase, perform two-point overtemperature judgment.

[0048] When the temperature rise data of more than four temperature points exceeds the temperature rise fixed value ΔT set , perform combined judgment according to one-point, two-point, and three-point overtemperature judgments.

[0049] Specifically, when there are more than four points, it is a combined judgment of one point, two points, and three points, and perform one-point, two-point, and three-point judgments. For example, if the temperature rise data of four points exceeds the temperature rise fixed value, first perform three-point judgment for different phases, and then perform one-point judgment.

[0050] When the temperature rise data of five points exceeds the temperature rise fixed value, first perform three-point judgment for different phases, and then perform judgment on the remaining two points.

[0051] When the temperature rise data of six points exceeds the temperature rise fixed value, first perform three-point judgment for different phases, and then perform judgment on the remaining three points.

[0052] In this embodiment, the typical correlation coefficient calculation formula is expressed as formula (1):

[0053]

[0054] Among them, X1 and X2 represent the data for calculating the correlation coefficient required, ΔX1 and ΔX2 represent the differences between two adjacent sampling points of the data, k identifies the current sampling point time, and fs is the sampling frequency.

[0055] Preferably, the first preset value of this embodiment is 0.3, and the second preset value of this embodiment is 0.8.

[0056] This embodiment also provides a monitoring system for preventing mis-alarm of switch contact temperature. The system includes a temperature acquisition unit, a signal conditioning unit, a microprocessor, and a wireless data transmission unit; the temperature acquisition unit acquires the switch contact temperature signal and the ambient temperature, and transmits them to the microprocessor through the signal conditioning unit for monitoring and calculation. The microprocessor converts them into digital signals using its own A / D module, and finally transmits each temperature signal to the monitoring center and the display interface through the wireless data transmission unit; in the display interface, the health status of the switch contact is monitored online.

[0057] In practical applications, the monitoring system acquires the switch contact temperature and each contact has no less than one temperature acquisition point, acquires the current of each phase and the ambient temperature, and sends them to the monitoring system for monitoring and calculation; the anti-mis-alarm monitoring method of this embodiment is characterized by a monitoring method of composite calculation of contact temperature, ambient temperature, and phase current.

[0058] The specific monitoring steps of this monitoring method are as follows:

[0059] Let the acquired temperatures be TA1, TA2, TB1, TB2, TC1, TC2 respectively, the ambient temperature be Ty, and the three-phase currents be IA, IB, and IC.

[0060] 1. Calculate the real-time temperature rise data of each contact temperature point by subtracting the ambient temperature Ty from the contact temperature, which are ΔTA1, ΔTA2, ΔTB1, ΔTB2, ΔTC1, and ΔTC2 respectively;

[0061] 2. Acquire the three-phase currents IA, IB, and IC, and calculate the power frequency effective values IA rms , IB rms , IC rms ;

[0062] 3. ΔT set is the temperature rise fixed value. When the temperature rise of any one of ΔTA1, ΔTA2, ΔTB1, ΔTB2, ΔTC1, and ΔTC2 exceeds ΔT set , go to step 4;

[0063] 4. Solve the correlation coefficient P between the temperature rise and the phase current according to the typical correlation coefficient calculation formula. ΔTA1_IA , P ΔTA2_IA , P ΔTB1_IB , P ΔTB2_IB , P ΔTC1_IC , P ΔTC2_IC ;

[0064] 5. Solve the correlation coefficient P according to the typical correlation coefficient calculation formula. ΔTA1_IA and P ΔTA2_IA between, P ΔTB1_IB and P ΔTB2_IB between, and P ΔTC1_IC and P ΔTC2_IC between the correlation coefficients.

[0065] 6. When there are N temperature rises exceeding the temperature rise set value ΔT set , determine the alarm condition according to the second correlation coefficient . When the alarm condition lasts for more than the alarm delay time t set , send out an over-temperature alarm signal.

[0066] In step 6 above, the alarm judgment specifically includes the following points:

[0067] (1) When only 1 temperature rise exceeds ΔT set , taking ΔTA1 as an example, ΔTA1 is greater than ΔT set , and is less than 0.3, and are greater than 0.8 and then start timing. When the above conditions last for more than the alarm delay time t set , send out a single-phase single-point over-temperature alarm; similarly, the judgment of other point temperature rises is the same as above.

[0068] (2) When 2 temperature rises exceed ΔT set , if the 2 points are in the same phase, taking ΔTA1 and ΔTA2 as an example, both ΔTA1 and ΔTA2 are greater than ΔT set , and is greater than 0.8 and then start timing. When the above conditions last for more than the alarm delay time t set , send out a single-phase over-temperature alarm; if the 2 points are in different phases, taking ΔTA1 and ΔTB1 as an example, both ΔTA1 and ΔTB1 are greater than ΔT set , and is less than 0.3, is less than 0.3, is greater than 0.8 and then start timing. When the above conditions last for more than the alarm delay time t setAfter that, a two-point over-temperature warning is issued. Similarly, the temperature rise judgment for other points is the same as above.

[0069] (3) When the temperature rise of three points exceeds ΔT set , when the three points are in different phases, taking ΔTA1, ΔTB1, and ΔTC1 as examples, both ΔTA1, ΔTB1, and ΔTC1 are greater than ΔT set , and both are greater than 0.8 and then start timing. When the above conditions last for more than the warning delay time t set after that, a three-point over-temperature warning is issued; when two points are in the same phase, the two-point over-temperature judgment is executed;

[0070] (4) When the temperature rise of more than four points exceeds ΔT set , the combined judgment is carried out according to the one-point, two-point, and three-point over-temperature judgments.

[0071] Therefore, the present invention divides the temperature point determination methods for one point, two points, and three points. When there are more than four points, the combination of 1, 2, and 3 can be used for judgment, and the number of identified points and accuracy are higher; in the monitoring process of the present invention, the temperature rise data and current data are combined, and the change process calculation of the correlation between the temperature rise and the current is realized on the basis of the combination. The correlation of the change process is judged, and the timing process has the effect of trend accumulation, which not only ensures the accuracy of the warning monitoring but also avoids the problem of false alarms in the reported warnings caused by single temperature overlimit or excessive sensitivity.

[0072] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not conflict, it should be considered as the scope described in this specification.

[0073] The above embodiments are only the preferred embodiments of the present invention, and the scope of protection of the present invention cannot be limited thereby. Any non-substantial changes and substitutions made by those skilled in the art on the basis of the present invention belong to the scope required to be protected by the present invention.

Claims

1. A method for preventing mis-alarm monitoring of the temperature of a switch contact, characterized in that, The method includes the following steps: Calculate the real-time temperature rise data of each switch contact temperature point, which are ΔTA1, ΔTA2, ΔTB1, ΔTB2, ΔTC1, and ΔTC2 respectively; Collect three-phase currents IA, IB, and IC, and calculate the power-frequency effective values IA rms , IB rms , IC rms ; Determine whether the temperature rise of any one of the contact temperature points exceeds the temperature rise set value ΔT set ; If the judgment result is yes, according to the typical correlation coefficient calculation formula, the first correlation coefficient P between the temperature rise and the phase current is calculated ΔTA1_IA , P ΔTA2_IA , P ΔTB1_IB , P ΔTB2_IB , P ΔTC1_IC , P ΔTC2_IC ; According to the typical correlation coefficient calculation formula, the correlation coefficient P is calculated ΔTA1_IA and P ΔTA2_IA between, P ΔTB1_IB and P ΔTB2_IB between, and P ΔTC1_IC and P ΔTC2_IC between the second correlation coefficient P PΔTA1_IA_PΔTA2_IA , P PΔTB1_IB_PΔTB2_IB , P PΔTC1_IC_PΔTC2_IC ; When the temperature rise at N points exceeds the temperature rise set value ΔT set According to the second correlation coefficient P PΔTA1_IA_PΔTA2_IA , P PΔTB1_IB_PΔTB2_IB , P PΔTC1_IC_PΔTC2_IC Determine the alarm condition. When this alarm condition persists for more than the alarm delay time t set After that, an over-temperature alarm signal is issued, where N≥1.

2. The method according to claim 1, wherein The calculation of the real-time temperature rise data of each contact temperature point includes: Obtain the temperatures of each switch contact TA1, TA2, TB1, TB2, TC1, TC2 and the ambient temperature Ty, subtract the ambient temperature Ty from the temperatures of each switch contact, and calculate the real-time temperature rise data of each contact temperature point. Among them, when collecting the switch contact temperature, each contact has no less than one temperature collection point.

3. The method according to claim 1, wherein: When the temperature rise data of only 1 temperature point exceeds the temperature rise set value ΔT set Taking ΔTA1 as an example, when ΔTA1 is greater than ΔT set and P PΔTA1_IA_PΔTA2_IA is less than the first preset value, and P PΔTB1_IB_PΔTB2_IB and P PΔTC1_IC_PΔTC2_IC are greater than the second preset value, start timing. When this alarm condition lasts for more than the alarm delay time t set a 1-point overtemperature alarm signal is issued.

4. The method according to claim 1, wherein: When the temperature rise data of two points exceed the temperature rise set value ΔT set If the two temperature points are in the same phase, taking ΔTA1 and ΔTA2 as examples, that is, both ΔTA1 and ΔTA2 are greater than ΔT set , and P PΔTA1_IA_PΔTA2_IA starts timing after exceeding the second preset value. When this alarm condition lasts for more than the alarm delay time t set , a single-phase overtemperature alarm signal is issued.

5. The method according to claim 4, wherein: When two temperature points are in different phases, taking ΔTA1 and ΔTB1 as examples, that is, both ΔTA1 and ΔTB1 are greater than ΔT set , and P PΔTA1_IA_PΔTA2_IA is less than the first preset value, P PΔTB1_IB_PΔTB2_IB is less than the first preset value, P PΔTC1_IC_PΔTC2_IC starts timing after being greater than the second preset value. When this alarm condition lasts for more than the alarm delay time t set , a two-point over-temperature alarm signal is issued.

6. The method according to claim 1, wherein: When the temperature rise data of three points exceed the temperature rise set value ΔT set , when the three temperature points are in different phases, taking ΔTA1, ΔTB1, and ΔTC1 as examples, both ΔTA1, ΔTB1, and ΔTC1 are greater than ΔT set , and P PΔTA1_IA_PΔTA2_IA , P PΔTB1_IB_PΔTB2_IB , P PΔTC1_IC_PΔTC2_IC all greater than the second preset value, start timing. When this alarm condition lasts for more than the alarm delay time t set , send out an over-temperature alarm signal for three points.

7. The method according to claim 6, wherein: When it is determined that the temperature rise data of 3 temperature points exceed the temperature rise set value ΔT set , and 2 temperature points are in the same phase, perform the 2-point overtemperature judgment.

8. The method according to claim 1, wherein: When the temperature rise data of more than 4 temperature points exceed the temperature rise set value ΔT set perform combined judgment according to the over-temperature judgment of 1 point, 2 points, and 3 points.

9. The method according to any one of claims 1 to 8, wherein: The typical correlation coefficient calculation formula is expressed as formula (1): Wherein, X1 and X2 represent the data for which the correlation coefficient needs to be calculated, ΔX1 and ΔX2 represent the differences between two sampling points of the data, k identifies the current sampling point moment, and fs is the sampling frequency.

10. The method according to any one of claims 3 to 8, wherein: The first preset value is 0.3, and the second preset value is 0.8.

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