A method for online monitoring of abnormal switch output operation of switch cabinet

Abstract

The present invention discloses an online monitoring method for abnormal switch output operation in a switch cabinet. The method collects the auxiliary power supply current of the switch cabinet, converts the current into an analog signal, converts it into a digital signal via an analog-to-digital converter (AD) and transmits it to a DSP. The method filters out any external electromagnetic interference that may affect the signal. After the switch output operation, the sampled data is cut off for a valid length and an abnormality algorithm is used to determine the characteristics of the switch output operation. Based on the algorithm results, a warning is issued regarding abnormal switch output operation. The present invention can not only determine abnormal switch output operation in real time and issue a warning, but can also preemptively identify potential hazards within the cabinet, effectively preventing operational failures.

Description

Technical Field

[0001] The present invention belongs to the field of state monitoring and diagnosis of switch cabinets in a DC traction power supply system, and in particular relates to an online monitoring method for abnormal operation of switch outputs 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 control the back-end equipment to be put into use or taken out of use through the switching output of the relay protection device.

[0003] Switchgear integrates multiple electrical devices, including circuit breakers, protective relays, relays, and contactors. Signal connections between these devices are complex. Signal characteristics can be categorized as digital, analog, and communication. Analog and communication signal status anomalies can be intuitively identified through data analysis. However, digital signals are only distinguished as "on" or "off," with no other statuses to identify anomalies. Problems are often discovered only during operation, impacting equipment power supply.

[0004] As switchgear functions develop and improve, the electrical connection systems within the switchgear become increasingly complex. This reduces reliability and increases the difficulty of troubleshooting, causing sudden failures to affect operations. 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 the switch output of a switch cabinet.

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

[0007] Step 1: The analog acquisition module converts the current signal of the switch cabinet auxiliary power supply 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 3: After receiving the output information from the switch output control module, the abnormality identification algorithm module intercepts a section of the current waveform data of the analog acquisition module according to the output type characteristics of the switch output control module for abnormality identification, fault prediction and abnormality alarm.

[0010] Furthermore, the abnormality identification step is:

[0011] S1, identification action starting point: 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 is I0, the starting point of the switch output operation is t0, k=0~9, 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 -I0), parameter A=0.3~0.8, satisfying I n <I τ <I n+1 The moment of t1 is the characteristic point;

[0013] S3, define a lower limit M of the fault min and an upper limit M for failure max , where M min and M max It 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 t1-t0<M min Or t1-t0>M max , it is considered that the switch output operation is abnormal and an alarm is issued. 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 failure 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 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 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 of 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 algorithms can be added to the operation processors of relay protection devices or various controllers to increase the reliability of switchgear equipment applications.

[0019] 3. Based on the relay protection device in the switch cabinet, while performing switching output, the controlled action module is judged by a series of algorithms to see whether it is abnormal, and an alarm can be given for potential faults to avoid unexpected problems during operation and use that 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 figures are: 11 - monitoring module, 12 - switch output control module, 13 - analog quantity acquisition module, 14 - abnormality identification algorithm module. DETAILED DESCRIPTION

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

[0024] When the feeder switchgear 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 is provided on a main control board, which is composed of three parts: a switch output control module 12, an analog acquisition module 13 and an abnormality identification algorithm module 14. All of the 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 acquisition module 13 collects the 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 identification algorithm 14 run by the DSP of the main control board detects the operation signal of the switch output control module 12, and simultaneously starts recording the switch cabinet auxiliary power supply current waveform transmitted by the analog acquisition module 13 for the abnormality alarm algorithm; the switch output control module 12 and the analog acquisition module 13 are respectively connected to the abnormality identification algorithm module 14.

[0026] The analog acquisition module 13 collects the switchgear auxiliary power supply current in real time, with a sampling interval of 0.1ms. When the switch output control module 12 triggers the output, it stores the subsequent 4000 sampling points and combines them into a 400ms current waveform. The abnormality identification algorithm module 14 then calculates the stored waveform based on the output operating characteristics.

[0027] The data is transmitted to the DSP chip processor of the main control board for real-time reading. The abnormality recognition algorithm of the DSP of the main control board detects a switch output command and starts recording the switch cabinet power supply current waveform for a period of time for the abnormality 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 acquisition 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. The processor identifies the abnormality of the switch output operation according to the results of the abnormality identification algorithm and monitors and alarms in real time. The monitoring method includes the following steps.

[0031] In 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 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, identification action starting point: 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 When (k ranges from 0, 1 to 9) are all satisfied, it is considered that 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;

[0036] S2, time constant characteristic moment: take the maximum value of the current waveform I max , I τ =A(I max -I0), satisfying I n <I τ <I n+1 The moment of the characteristic point is t1; the parameter A is the best parameter, which cuts off the time of the first part of the waveform with the fastest current rise rate, and takes a value of 0.3 to 0.8.

[0037] S3, fault alarm setting: record M = t1-t0 as the time constant of the RC coil, and define a fault lower limit M min and an upper limit M for failure max , where M min and M max It 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 t1-t0<M min Or t1-t0>M max , it is considered that the switch output operation is abnormal and an alarm is issued.

[0038] Counting parameter ΔI of anomaly recognition algorithm set The selection is based on the current change rate characteristics of the relay action coil, M min and Mmax 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 line is loose.

[0039] When the operation object of the switch output has multiple continuous action modules or mechanisms, 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 the abnormal output of the switching quantity 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 failure Mn max judgment.

[0041] The above processes are all completed inside the DSP chip of the main control board. After 400ms of each actual operation, the switch output operation is detected online for abnormalities, such as t1-t0<M min or M max <t1-t0, 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 Shown: Auxiliary power supply current collection real-time point n data I n , data input and operation starting point t0 and feature point t1 are performed, where the operation starting point t0 process is: when I n+k+1 -I n+k >ΔI set When (k ranges from 0 to 9) are all satisfied, take I at this time n is I0, and the corresponding n is t0. The process at the characteristic time point t1 is: the maximum value of the waveform I max , I τ =0.63(I max -I0), when I n+1 >I τ And I n <I τ The time point is t1. The abnormality identification process is: if M min <t1-t0<M max It is considered that there is no abnormality in the operation and no abnormal alarm will be issued in this range.

[0043] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some embodiments of its application. A person skilled in the art may make several modifications and improvements without departing from the inventive concept of the present invention, and all of these modifications and improvements fall within the scope of protection of the present invention.

Claims

1. A method for online monitoring of abnormal switch output operation of a switch cabinet, characterized by: The monitoring module (11) is composed of a switch output control module (12), an analog acquisition module (13) and an abnormality identification algorithm module (14); and 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 recognition algorithm module (14); Step 3: After receiving the output information from the switch output control module (12), the abnormality identification algorithm module (14) intercepts a section of current waveform data from the analog acquisition module (13) for abnormality identification, fault prediction and abnormality alarm; 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 t1 is the characteristic point; S3, record the time constant M=t1-t0 of the RC coil and define a lower limit M for the fault min and an upper limit M for failure 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.

2. The method for online monitoring of abnormal switch output operation of a switch cabinet according to claim 1, 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 interrupt frequency f of the DSP chip is 10 kHz.

3. The method for online monitoring of abnormal switch output operation of a switch cabinet according to claim 2, 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 0.1ms. 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.

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