On-line monitoring method for abnormal switching value output operation of switch cabinet

Abstract

The invention discloses an on-line monitoring method for abnormal switching value output operation of a switch cabinet, and the method comprises the steps: collecting the auxiliary power supply current of the switch cabinet, converting the current into an analog signal, converting the analog signal into a digital signal through an AD, transmitting the digital signal to a DSP, and filtering the influence of external electromagnetic interference on the signal. After the switching value output operation is carried out, the effective length of the sampling data is intercepted, abnormal algorithm judgment is carried out according to the characteristics of the switching value output operation, and switching value output abnormity warning is carried out according to the result of the algorithm. According to the invention, switching value output operation abnormity can be judged in real time, an alarm can be given, hidden danger points in the cabinet can be found in advance, and the fault of operation failure can be effectively prevented.

Description

Technical Field

[0001] The present invention belongs to the field of switch cabinet status monitoring and diagnosis of a DC traction power supply system, and in particular relates to an online monitoring method for abnormal output operation of a switching quantity in a switch cabinet. Background Art

[0002] Switchgear is a key electrical equipment in the DC traction power supply system. It is used to monitor and control the operating status of the back-end electrical equipment, and automatically or manually put the back-end equipment into use or out of use through the switch output of the relay protection device.

[0003] The switch cabinet integrates multiple electrical devices such as circuit breakers, relay protection devices, relays, contactors, etc., and the signal connections between the devices are complex. According to the signal characteristics, it can be divided into switch signals, analog signals, and communication signals. Among them, the abnormal status of analog signals and communication signals can be intuitively judged through data, but the switch signal only distinguishes between "on" and "off", and there is no other status to judge the abnormality. Problems are often discovered during operation, affecting the power supply of the equipment.

[0004] As the functions of switchgear develop and improve, the electrical connection system in the switchgear becomes more and more complicated. On the one hand, the reliability is reduced, and on the other hand, it makes troubleshooting more difficult and sudden faults affect operation. Summary of the invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and to propose an online monitoring method for abnormal operation of switch quantity output of a switch cabinet.

[0006] The technical solution adopted by the present invention to solve the technical problem is: an online monitoring method for abnormal operation of switch quantity output of a switch cabinet, based on a monitoring module composed of a switch quantity output control module, an analog quantity acquisition module and an abnormality identification algorithm module, wherein the switch quantity output control module and the analog quantity acquisition module are respectively connected to the abnormality identification algorithm module; comprising the following steps:

[0007] Step 1: The analog quantity acquisition module converts the current signal of the auxiliary power supply of the switch cabinet into a digital signal, pre-processes the digital signal to filter out high-frequency interference in the signal, and transmits it to the abnormality recognition algorithm module;

[0008] Step 2: The switch output control module controls the switch output according to the function of the relay protection, and transmits the output information to the abnormality identification algorithm module. The operation object of the switch output is mainly the relay action coil;

[0009] Step three, after receiving the output information of the switch output control module, the abnormal identification algorithm module intercepts a section of the current waveform data of the analog quantity acquisition module according to the output type characteristics of the switch output control module for abnormal identification, fault prediction and abnormal alarm.

[0010] Further, the abnormality identification step is:

[0011] S1, identify the starting point of the action: define the current data of the intercepted current waveform as I n , the latter data is I n+1 , n is the sampling point, when I n+k+1 -I n+k >ΔI set And when all the conditions from 0, 1 to k are satisfied, it is considered that at this moment I n The value of I 0 , the starting point of the switch output operation is t 0 , k = 0 to 9, ΔI set is the current counting parameter;

[0012] S2, time constant characteristic moment: take the maximum value of the current waveform I max , I τ =A(I max -I 0 ), parameter A = 0.3 ~ 0.8, satisfying I n <I τ <I n+1 The time point is the characteristic point time t 1 ;

[0013] S3, define a lower limit M of the fault min and an upper limit M of the fault max , where M min and M max is the time counting parameter, which is selected according to the characteristics of the switch output control object. Different parameters are preset according to the type of operation object. If t 1 -t 0 <M min or 1 -t 0 >M max , the switch output operation is considered abnormal and an alarm is triggered. The judgment method of switch output abnormality can flexibly set multiple characteristic points to map more fault modes according to the current characteristics of the control device. The time difference between each characteristic point and the counting 0 point can be used to determine the lower limit Mn of the fault. min and the upper limit of fault Mn max judgment.

[0014] Furthermore, the monitoring module is based on a DSP chip and is arranged on a main control board of a relay protection device of a switch cabinet, and an interrupt frequency f of the DSP chip is set to 10 kHz.

[0015] Furthermore, the analog quantity acquisition module collects the power supply current analog signal after the current sensor on the auxiliary power supply of the switch cabinet in real time based on the AD module, with a sampling interval of 0.1ms. When the switch quantity output control module triggers the output, it stores the subsequent 4000 sampling point data and combines them into a 400ms current waveform.

[0016] The beneficial effects of the present invention are:

[0017] 1. For common switch cabinets, the present invention has a core operation module relay protection device, which can realize the switch output operation in the software while performing online monitoring on the hidden dangers of the switch output operation circuit and the operated relays, circuit breakers and other actuators.

[0018] 2. The application method of the present invention is simple, and software algorithm implementation can be added to the operation processor of the relay protection device or various controllers to increase the reliability of the switch cabinet equipment application.

[0019] 3. While the relay protection device in the switch cabinet is outputting the switching quantity, a series of algorithms are used to determine whether the controlled action module is abnormal. This can alarm for potential faults and avoid unexpected problems during operation that may affect the power supply of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a hardware structure diagram of the monitoring module of the present invention;

[0021] Figure 2 It is a flow chart of the control method adopted by the present invention.

[0022] The reference numerals of the drawings are: 11 - monitoring module, 12 - switch quantity output control module, 13 - analog quantity acquisition module, 14 - abnormality identification algorithm module. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the embodiments provided herein are only used to explain the present application and are not used to limit the present application.

[0024] When the feeder switch cabinet of the subway DC traction system uses a relay protection device to realize the protection and control functions, the hardware structure of the patented method can be used to realize the protection and control functions. Figure 1 shown.

[0025] The present invention discloses an online monitoring method for abnormal operation of switch output of a switch cabinet. A monitoring module 11 composed of three parts, a switch output control module 12, an analog quantity acquisition module 13 and an abnormality recognition algorithm module 14, is provided on a main control board. The three parts are implemented by a DSP chip of the main control board, and the interrupt frequency f of the DSP is set to 10kHz. The analog quantity acquisition module 13 collects auxiliary power supply current, converts the current analog signal into a digital signal, and transmits it to the DSP operation processor of the main control board for real-time reading. The abnormality recognition algorithm 14 run by the DSP of the main control board detects the operation signal of the switch output control module 12, and starts to record the auxiliary power supply current waveform of the switch cabinet transmitted by the analog quantity acquisition module 13 at the same time, which is used for the abnormal alarm algorithm. The switch output control module 12 and the analog quantity acquisition module 13 are respectively connected to the abnormality recognition algorithm module 14.

[0026] The analog quantity acquisition module 13 collects the auxiliary power supply current of the switch cabinet in real time, with a sampling interval of 0.1ms. When the switch quantity output control module 12 triggers the output, it stores the subsequent 4000 sampling point data and combines them into a 400ms current waveform. The abnormal identification algorithm module 14 then calculates the stored waveform according to the output operation characteristics.

[0027] The data is transmitted to the DSP chip processor of the main control board for real-time reading. The abnormal identification algorithm of the DSP of the main control board detects that there is a switch output command, and starts to record the power supply current waveform of the switch cabinet for a period of time for the abnormal alarm algorithm:

[0028] Step 1: Collection of analog quantity of relay protection device: The current ±10A of auxiliary power supply of switch cabinet is converted into ±10mA signal through current Hall sensor, which is collected and converted into digital signal by analog quantity collection module 13, and high-frequency interference in external electromagnetic signal is filtered out.

[0029] Step 2: While performing logic output, the switch output control module 12 sends output information to the abnormality identification algorithm module 14. The abnormality identification algorithm module 14 saves the waveform data of the next 4000 points for a total of 400ms in a step size of 0.1ms.

[0030] Step 3: The abnormality identification algorithm module 14 applies the corresponding abnormality identification algorithm according to the characteristics of the switch output operation object, and the processor identifies the abnormality of the switch output operation according to the result of the abnormality identification algorithm and monitors and alarms in real time. The monitoring method includes the following steps.

[0031] Step 1: The analog quantity acquisition module 13 converts the current signal of the auxiliary power supply of the switch cabinet into a digital signal, pre-processes the digital signal to filter out high-frequency interference in the signal, and transmits it to the abnormality recognition algorithm module 14.

[0032] Step 2: the switch output control module 12 controls the switch output according to the function of the relay protection, and transmits the output information to the abnormality identification algorithm module 14, wherein the operation object of the switch output is mainly the relay action coil.

[0033] Step three, after receiving the output information of the switch output control module 12, the abnormality identification algorithm module 14 intercepts a section of the current waveform data of the analog quantity acquisition module 13 according to the output type characteristics of the switch output control module 12 for abnormality identification, fault prediction and abnormality alarm.

[0034] The abnormality identification steps are as follows.

[0035] S1, identify the starting point of the action: define the current data of the intercepted current waveform as I n , the latter data is I n+1 , n is the sampling point, when I n+k+1 -I n+k >ΔI set (k from 0, 1 to 9) are all satisfied, it is considered that at this moment I n The value of I 0 , the starting point of the switch output operation is t 0 , k = 0 to 9, ΔI set is the current counting parameter;

[0036] S2, time constant characteristic moment: take the maximum value of the current waveform I max , I τ =A(I max -I 0 ), satisfying I n <I τ <I n+1 The time point is the characteristic point time t 1 ; Parameter A is the best parameter, which cuts off the time of the first part of the waveform with a fast current rise rate, and takes a value of 0.3 to 0.8.

[0037] S3, Fault alarm setting: record M=t 1 -t 0 is the time constant of the RC coil, and defines a lower limit M for the fault min and an upper limit M of the fault max , where M min and M max is the time counting parameter, which is selected according to the characteristics of the switch output control object. Different parameters are preset according to the type of operation object. If t 1 -t 0 <M min or 1 -t 0 >Mmax , it is considered that the switch output operation is abnormal and an alarm is issued.

[0038] Counting parameter ΔI of anomaly identification algorithm set The selection is based on the current change rate characteristics of the relay action coil, M min and M max The selection is based on the parameter characteristics of the relay action coil. If the actual waveform is less than M min It is believed that the impedance characteristic becomes smaller and there are hidden dangers such as insulation aging. If it is greater than M max It is believed that the impedance increases and the circuit is loose.

[0039] When the operation object of the switch output has multiple continuous action modules or mechanism executions, the waveform is the superposition of several groups of rising segments. For each group of rising segments, different calculation parameters ΔIn can be selected according to the above method. set , Mn min and Mn max , each segment maps different operational exceptions.

[0040] The judgment method of switch output abnormality can flexibly set multiple characteristic points to map more fault modes according to the current characteristics of the control device. The time difference between each characteristic point and the counting 0 point can be used to determine the lower limit Mn of the fault. min and the upper limit of fault Mn max judgment.

[0041] The above processes are all completed inside the DSP chip of the main control board. After each actual operation condition is executed for 400ms, the switch output operation is identified for abnormalities online. 1 -t 0 <M min or M max <t 1 -t 0 , the algorithm immediately generates a fault alarm, prompting you to check the corresponding switch output circuit equipment or wiring.

[0042] Apply this method to realize the algorithm logic, such as Figure 2 As shown: the data of the auxiliary power supply current collected at real time point n I n , data input and operation starting point t 0 and feature point t 1 The operation starts from t 0 The process is: When I n+k+1 -I n+k >ΔI set (k from 0 to 9) are all satisfied, take I at this time n For I 0 , the corresponding n is t 0 . Characteristic time point t 1The process is: the maximum value of the waveform I max , I τ =0.63(I max -I 0 ), when I n+1 >I τ And I n <I τ The time point is t 1 The abnormal identification process is: if M min <t 1 -t 0 <M max It is considered that there is no abnormality in the operation, and no abnormal alarm will be issued in this interval.

[0043] The above embodiments are only illustrative of the principles and effects of the present invention, as well as some embodiments of its application. For those skilled in the art, several modifications and improvements may be made without departing from the creative concept of the present invention, and all of these belong to the protection scope of the present invention.

Claims

1. A method for online monitoring of abnormal switch output operation of a switch cabinet, characterized in that: A monitoring module (11) composed of a switch quantity output control module (12), an analog quantity acquisition module (13) and an abnormality identification algorithm module (14) comprises the following steps: Step 1: The analog quantity acquisition module (13) converts the current signal of the auxiliary power supply of the switch cabinet into a digital signal, pre-processes the digital signal, and transmits it to the abnormality recognition algorithm module (14); Step 2: the switch output control module (12) controls the switch output of the relay action coil and transmits the output information to the abnormality identification algorithm module (14); Step three, after receiving the output information of the switch output control module (12), the abnormality identification algorithm module (14) intercepts a section of current waveform data of the analog quantity acquisition module (13) for abnormality identification, fault prediction and abnormality alarm.

2. The method for online monitoring of abnormal switch output operation of a switch cabinet according to claim 1 is characterized in that: The abnormality identification steps are: S1, defines the current data of the intercepted current waveform as I n , the latter data is I n+1 , n is the sampling point, when I n+k+1 -I n+k >ΔI set At this moment I n The value of is I0, the starting point of the switch output operation is t0, k = 0 ~ 9, ΔI set is the current counting parameter; S2, take the maximum value of the current waveform I max , I τ =A(I max -I0), parameter A = 0.3 ~ 0.8, satisfying I n <I τ <I n+1 The moment of is the characteristic point moment t1; S3, record the time constant of the RC coil M = t1-t0, and define a lower limit M for the fault min and an upper limit M of the fault max , if t1-t0<M min Or t1-t0>M max , it is considered that the switch output operation is abnormal and an alarm is issued.

3. A method for online monitoring of abnormal switch output operation of a switch cabinet according to claim 1 or 2, characterized in that: The monitoring module (11) is based on a DSP chip and is arranged on a main control board of a relay protection device of a switch cabinet. The interruption frequency f of the DSP chip is 10 kHz.

4. The method for online monitoring of abnormal switch output operation of a switch cabinet according to claim 3 is characterized in that: The analog quantity acquisition module (13) acquires the power supply current analog signal after the current sensor on the auxiliary power supply of the switch cabinet in real time based on the AD module, with a sampling interval of 0.1 ms. When the switch quantity output control module (12) triggers the output, it stores the subsequent 4000 sampling point data and combines them into a 400 ms current waveform.

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