A LF furnace water cooling cable circuit breaker fault diagnosis system and fault diagnosis method

Abstract

The present invention belongs to the field of refining technology, and specifically relates to a LF furnace water-cooling cable circuit breaker fault diagnosis system and a fault diagnosis method. The water-cooling cable circuit breaker fault diagnosis system of the present invention includes a transformer short network, two water-cooling cables, two water-cooling cable cooling water return pipes, a fault diagnosis detector, two water-cooling cable cooling water return flow detection units, two water-cooling cable cooling water return temperature detection units and water-cooling cable current detection units. This system determines the broken fault line of the water-cooling cable by establishing a water-cooling cable temperature model under normal conditions, comparing the temperature value of the real-time water-cooling cable with the water-cooling cable temperature model, greatly reducing the difficulty of troubleshooting the water-cooling cable fault, shortening the water-cooling cable fault recovery time, and providing a strong guarantee for the stable operation of the entire production line.

Description

Technical Field

[0001] The invention belongs to the technical field of refining, and in particular relates to a LF furnace water-cooling cable circuit breaker fault diagnosis system and a fault diagnosis method. Background Art

[0002] The water-cooling cable is an important component in the high-current circuit of the LF furnace. In order to ensure the passage of high current in each phase of the main circuit, the single-phase cross arm is connected to the transformer short network by two water-cooling cables in parallel. In the actual smelting process, the water-cooling cable moves up and down with the electrode cross arm and swings left and right due to the electromagnetic force generated by the current passing through the water-cooling cable. In the actual production process, with day-to-day production, the flexible cable in the water-cooling cable will age, and the flexible cable in a water-cooling cable connected to a phase cross arm will break, resulting in interruption of production and smelting. Due to the large size and heavy weight of a water-cooling cable, it takes several hours to replace a water-cooling cable. If it is impossible to accurately determine which water-cooling cable is faulty, the time to resume production will increase, greatly affecting the production efficiency. Summary of the invention

[0003] The present invention provides a LF furnace water-cooling cable circuit breaker fault diagnosis system and a fault diagnosis method, aiming to provide a fault diagnosis method that can accurately locate the circuit breaker fault water-cooling cable and reduce the difficulty of troubleshooting the water-cooling cable fault.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A LF furnace water-cooling cable circuit breaker fault diagnosis system at least comprises a transformer short network, two water-cooling cables and two water-cooling cable cooling water return pipes, each water-cooling cable is connected to a water-cooling cable cooling water return pipe, and the two water-cooling cables are respectively connected to the transformer short network; it also comprises a fault diagnosis detector, two water-cooling cable cooling water return flow detection parts, two water-cooling cable cooling water return temperature detection parts and a water-cooling cable current detection part; each water-cooling cable cooling water return pipe is respectively connected to a water-cooling cable cooling water return flow detection part and a water-cooling cable cooling water return temperature detection part, and the water-cooling cable current detection part is ringed on the transformer short network; the fault diagnosis detector is respectively connected to the two water-cooling cable cooling water return flow detection parts, the two water-cooling cable cooling water return temperature detection parts and the water-cooling cable current detection parts with electrical signals.

[0006] The water-cooled cable cooling water return flow detection unit is composed of an electromagnetic flowmeter.

[0007] The water-cooled cable current detection unit is composed of a Rogowski coil sensor.

[0008] The water-cooled cable cooling water return temperature detection unit is composed of a PT100 temperature sensor.

[0009] The fault diagnosis detector at least includes a receiving module, a calculation module, an output module and a display module; the receiving module is respectively connected to the two-way water-cooled cable cooling water return flow detection unit, the two-way water-cooled cable cooling water return temperature detection unit and the water-cooled cable current detection unit for electrical signals, and is used to receive the current data on the transformer short network and the return water flow and return water temperature data of the two-way water-cooled cable cooling water return pipes; the calculation module is used to establish a water-cooled pipe cable cooling water temperature model based on the acquired water-cooled pipe cable status data, and to calculate the deviation between the acquired real-time data and the water-cooled pipe cable cooling water temperature model; the output module is used to output the calculation result of the calculation module to the display module for displaying the water-cooled cable disconnection fault judgment result.

[0010] A LF furnace water cooling cable circuit breaker fault diagnosis method, using a LF furnace water cooling cable circuit breaker fault diagnosis system, comprising the following steps:

[0011] Step 1: The fault diagnosis detector obtains the actual current, actual return water flow rate and actual return water temperature data of the water-cooled cable under normal conditions;

[0012] Step 2: The fault diagnosis detector establishes a cooling water temperature model of the water-cooled cable according to the normal state data of the water-cooled cable obtained in step 1;

[0013] Step 3: The fault diagnosis detector obtains the water-cooling cable status data in real time and compares it with the cooling water temperature model of the water-cooling cable. When a short circuit fault occurs in the water-cooling cable, its real-time status data deviates from the temperature model. When the deviation value reaches the set threshold, the water-cooling cable is determined to be a short circuit fault water-cooling cable.

[0014] The water-cooled cable temperature prediction model established by the water-cooled cable cooling water temperature model in step 2 is as follows:

[0015] T(k+1)=f[Q(k),I(k),T(k)]

[0016] Where: Q(k) is the return flow rate of cooling water for water-cooled cables at time k;

[0017] I(k) is the current passing through the water-cooling cable at time k;

[0018] T(k) is the return water temperature of the water-cooled cable at time k;

[0019] T(k+1) is the return water temperature of the water-cooled cable at time k+1;

[0020] f is a nonlinear mapping determined by the neural network structure and parameters.

[0021] The specific method for establishing the cooling water temperature model of the water-cooled cable is as follows:

[0022] Step 1: Establish a BP neural network with a 3-8-1 network structure and initialize the neural network weights W and bias value b;

[0023] Step 2: Select n groups of input samples X and expected output T obtained in actual production as network training samples and perform normalization

[0024] X=[(Q1,I1,T1),(Q2,I2,T2),…,(Q i ,I i ,T i )] i=1,2,…,n

[0025] Y=[T2,T3,…,T i+1 ] i=2,3,…,n

[0026] Where: Q i is the i-th sampling value of the cooling water return flow rate of the water-cooled cable;

[0027] I i is the i-th sampling value of the water-cooling cable current;

[0028] T i is the i-th sampling value of the cooling water return temperature of the water-cooled cable;

[0029] i is the number of samples.

[0030] Step 3: Send the normalized data into the network for training with a learning rate of 0.01. When the expected error is less than 10-8, stop training the network and complete the establishment of the water-cooled cable temperature prediction model.

[0031] The specific method for the fault diagnosis detector in step 3 to obtain the water-cooled cable status data in real time and compare it with the water-cooled cable cooling water temperature model is as follows:

[0032] Step 1: According to the water-cooled cable cooling water temperature model established in step 2, calculate the temperature T of the water-cooled cable under normal conditions m ;

[0033] Step 2: Calculate the T output of the cooling water temperature model for water-cooled cables m The difference T between the actual water-cooled cable cooling water detection temperature T e =T-T m ;

[0034] Step 3: When T e ﹥Maximum allowable temperature deviation T α, then the number of determinations δ = δ + 1, otherwise, δ = 0, and return to step 2.

[0035] Step 4: When the number of determinations δ> the maximum allowable deviation number n, it is determined that the water-cooling cable is broken.

[0036] Where: T m Output temperature for the cooling water temperature model of water-cooled cables;

[0037] T is the actual return water temperature of the cooling water for the water-cooled cable;

[0038] T e The temperature difference between the actual water-cooled cable cooling water return temperature and the water-cooled cable cooling water temperature model output;

[0039] T α is the maximum allowable temperature deviation;

[0040] δ is the number of judgments;

[0041] n is the maximum number of deviations allowed.

[0042] Beneficial effects:

[0043] The present invention forms a water-cooled cable disconnection fault diagnosis system through a transformer short network, two water-cooled cables, two water-cooled cable cooling water return pipes, a fault diagnosis detector, two water-cooled cable cooling water return flow detection units, two water-cooled cable cooling water return temperature detection units and a water-cooled cable current detection unit. The system determines the disconnection fault line of the water-cooled cable by establishing a water-cooled cable temperature model under normal conditions and comparing the temperature value of the real-time water-cooled cable with the water-cooled cable temperature model, which greatly reduces the difficulty of troubleshooting water-cooled cable faults, shortens the water-cooled cable fault recovery time, and provides a strong guarantee for the stable operation of the entire production line.

[0044] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 It is a schematic diagram of a single-phase water-cooled cable fault diagnosis system of the present invention;

[0047] Figure 2The present invention is a flow chart of water-cooled cable fault diagnosis.

[0048] In the figure:

[0049] 1-fault diagnosis detector; 2-water-cooled cable current detection unit; 3-transformer short network; 4-first water-cooled cable; 5-second water-cooled cable; 6-first water-cooled cable cooling water return pipe; 7-second water-cooled cable cooling water return pipe; 8-first water-cooled cable cooling water return temperature detection unit; 9-second water-cooled cable cooling water return temperature detection unit; 10-first water-cooled cable cooling water return flow detection unit; 11-second water-cooled cable cooling water return flow detection unit.

[0050] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention. DETAILED DESCRIPTION

[0051] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Embodiment 1:

[0053] Reference Figure 1 The LF furnace water-cooling cable circuit breaker fault diagnosis system shown in the figure at least includes a transformer short network 3, two water-cooling cables and two water-cooling cable cooling water return pipes, each water-cooling cable is connected to a water-cooling cable cooling water return pipe, and the two water-cooling cables are respectively connected to the transformer short network 3; it also includes a fault diagnosis detector 1, two water-cooling cable cooling water return flow detection parts, two water-cooling cable cooling water return temperature detection parts and a water-cooling cable current detection part 2; each water-cooling cable cooling water return pipe is respectively connected to a water-cooling cable cooling water return flow detection part and a water-cooling cable cooling water return temperature detection part, and the water-cooling cable current detection part is ringed on the transformer short network 3; the fault diagnosis detector 1 is respectively connected to the two water-cooling cable cooling water return flow detection parts, the two water-cooling cable cooling water return temperature detection parts and the water-cooling cable current detection parts with electrical signals.

[0054] In actual use, the fault diagnosis detector 1 obtains the actual current, actual return water flow and actual return water temperature data of the water-cooled cable under normal conditions, and establishes a cooling water temperature model of the water-cooled cable based on the obtained data; thereafter, the fault diagnosis detector 1 obtains the real-time status data of the water-cooled cable, and compares it with the cooling water temperature model of the water-cooled cable. When a short circuit fault occurs in the water-cooled cable, its real-time status data deviates from the temperature model. When the deviation value reaches the set threshold, it is determined that the water-cooled cable is a short circuit fault water-cooled cable.

[0055] The use of this technical solution not only greatly reduces the difficulty of troubleshooting water-cooling cable faults during equipment maintenance and shortens the water-cooling cable fault recovery time, but also provides a strong guarantee for the stable operation of the entire production line.

[0056] Embodiment 2:

[0057] Reference Figure 1 The LF furnace water-cooling cable circuit breaker fault diagnosis system shown is based on the first embodiment, and the water-cooling cable cooling water return flow detection unit is composed of the water-cooling cable cooling water return flow detection unit which is composed of an electromagnetic flowmeter.

[0058] Furthermore, the water-cooled cable current detection unit 2 is composed of a Rogowski coil sensor.

[0059] Furthermore, the water-cooled cable cooling water return temperature detection unit is composed of a PT100 temperature sensor.

[0060] In actual use, the cooling water return flow detection unit of the water-cooled cable is used to detect the cooling water return flow rate; the water-cooled cable current detection unit is used to detect the current passing through the water-cooled cable; and the cooling water return temperature detection unit of the water-cooled cable is used to detect the cooling water return temperature.

[0061] The water-cooled cable cooling water return flow detection unit, the water-cooled cable current detection unit 2 and the water-cooled cable cooling water return temperature detection unit adopt this technical solution, which can not only meet the needs of obtaining relevant data, but also is easy to implement and has a low implementation cost.

[0062] Embodiment three:

[0063] Reference Figure 1The LF furnace water-cooling cable circuit breaker fault diagnosis system shown in the figure, on the basis of embodiment 1, the fault diagnosis detector 1 at least includes a receiving module, a calculation module, an output module and a display module; the receiving module is respectively connected with the two-way water-cooling cable cooling water return flow detection unit, the two-way water-cooling cable cooling water return temperature detection unit and the water-cooling cable current detection unit 2 by electrical signals, and is used to receive the current data on the transformer short network 3 and the return water flow and return water temperature data of the two-way water-cooling cable cooling water return pipes; the calculation module is used to establish a water-cooling pipe cable cooling water temperature model according to the acquired water-cooling pipe cable status data, and calculate the deviation between the acquired real-time data and the water-cooling pipe cable cooling water temperature model; the output module is used to output the calculation result of the calculation module to the display module to display the water-cooling cable disconnection fault judgment result.

[0064] In actual use, the fault diagnosis detector 1 adopts this technical solution to conveniently realize the functions of data acquisition, modeling and fault diagnosis result calculation, providing a guarantee for timely and accurate judgment of the LF furnace water cooling cable circuit breaker fault.

[0065] Embodiment 4:

[0066] Reference Figure 2 A LF furnace water cooling cable circuit breaker fault diagnosis method, using a LF furnace water cooling cable circuit breaker fault diagnosis system, includes the following steps,

[0067] Step 1: According to the water-cooled cable cooling water temperature model established in step 2, calculate the temperature T of the water-cooled cable under normal conditions m ;

[0068] Step 2: Calculate the T output of the cooling water temperature model for water-cooled cables m The difference T between the actual water-cooled cable cooling water detection temperature T e =T-T m ;

[0069] Step 3: When T e ﹥Maximum allowable temperature deviation T α , then the number of determinations δ = δ + 1, otherwise, δ = 0, and return to step 2.

[0070] Step 4: When the number of determinations δ> the maximum allowable deviation number n, it is determined that the water-cooling cable is broken.

[0071] Where: T m Output temperature for the cooling water temperature model of water-cooled cables;

[0072] T is the actual return water temperature of the cooling water for the water-cooled cable;

[0073] T eThe temperature difference between the actual water-cooled cable cooling water return temperature and the water-cooled cable cooling water temperature model output;

[0074] T α is the maximum allowable temperature deviation;

[0075] δ is the number of judgments;

[0076] n is the maximum number of deviations allowed.

[0077] Furthermore, the water-cooled cable temperature prediction model established by the water-cooled cable cooling water temperature model in step 2 is as follows:

[0078] T(k+1)=f[Q(k),I(k),T(k)]

[0079] Where: Q(k) is the return flow rate of cooling water for water-cooled cables at time k;

[0080] I(k) is the current passing through the water-cooling cable at time k;

[0081] T(k) is the return water temperature of the water-cooled cable at time k;

[0082] T(k+1) is the return water temperature of the water-cooled cable at time k+1;

[0083] f is a nonlinear mapping determined by the neural network structure and parameters.

[0084] Furthermore, the specific method for establishing the cooling water temperature model of the water-cooled cable is as follows:

[0085] Step 1: Establish a BP neural network with a 3-8-1 network structure and initialize the neural network weights W and bias value b;

[0086] Step 2: Select n groups of input samples X and expected output T obtained in actual production as network training samples and perform normalization

[0087] X=[(Q1,I1,T1),(Q2,I2,T2),…,(Q i ,I i ,T i )] i=1,2,…,n

[0088] Y=[T2,T3,…,T i+1 ] i=2,3,…,n

[0089] Where: Q i is the i-th sampling value of the cooling water return flow rate of the water-cooled cable;

[0090] I i is the i-th sampling value of the water-cooling cable current;

[0091] T i is the i-th sampling value of the cooling water return temperature of the water-cooled cable;

[0092] i is the number of samples.

[0093] Step 3: Send the normalized data into the network for training with a learning rate of 0.01. When the expected error is less than 10-8, stop training the network and complete the establishment of the water-cooled cable temperature prediction model.

[0094] The present invention establishes a water-cooling cable temperature model under normal conditions and compares the real-time water-cooling cable temperature value with the water-cooling cable temperature model to determine the broken fault line of the water-cooling cable, thereby greatly reducing the difficulty of troubleshooting water-cooling cable faults, shortening the water-cooling cable fault recovery time, and providing a strong guarantee for the stable operation of the entire production line.

[0095] Embodiment five:

[0096] Reference Figure 1 The LF furnace water-cooling cable circuit breaker fault diagnosis system shown in the figure comprises a fault diagnosis detector 1, a water-cooling cable current detection unit 2, a transformer short network 3, a first water-cooling cable 4, a second water-cooling cable 5, a first water-cooling cable cooling water return pipe 6, a second water-cooling cable cooling water return pipe 7, a first water-cooling cable cooling water return temperature detection unit 8, a second water-cooling cable cooling water flow detection unit 9, a first water-cooling cable cooling water return temperature detection unit 10 and a second water-cooling cable cooling water return temperature detection unit 11; the first water-cooling cable 4 is respectively connected to the first water-cooling cable cooling water return pipe 6 and the transformer short network 3, the first water-cooling cable 4, the second water-cooling cable cooling water return pipe 6, the second water-cooling cable cooling water return pipe 7, the first water-cooling cable cooling water return temperature detection unit 8, the second water-cooling cable cooling water flow detection unit 9, the first water-cooling cable cooling water return temperature detection unit 10 and the second water-cooling cable cooling water return temperature detection unit 11; the first water-cooling cable 4 is respectively connected to the first water-cooling cable cooling water return pipe 6 and the transformer short network 3, the first water-cooling cable 4 is respectively connected to the first water-cooling cable cooling water return pipe 6 and the transformer short network 3, the second water-cooling cable 5 is respectively connected to the first water-cooling cable cooling water return pipe 6 and the transformer short network 3, the first water-cooling cable 5 is respectively connected to the first water-cooling cable cooling water return pipe 6 and the transformer short network 3, the second water-cooling cable 5 is respectively connected to the first water-cooling cable cooling water return pipe 6 and the transformer short network 3, the first water-cooling cable cooling water return pipe 6 and the transformer short network 3, the second water-cooling cable cooling water return pipe 7, the first water-cooling cable cooling water return The transformer short network 3 is connected, and a first water-cooled cable cooling water flow detection unit 8 and a first water-cooled cable cooling water return temperature detection unit 10 are connected in parallel between the first water-cooled cable cooling water return pipe 6 and the fault diagnosis detector 1; the second water-cooled cable 5 is connected to the second water-cooled cable cooling water return pipe 7 and the transformer short network 3, and a second water-cooled cable cooling water flow detection unit 11 and a second water-cooled cable cooling water return temperature detection unit 9 are connected in parallel between the second water-cooled cable cooling water return pipe 7 and the fault diagnosis detector 1; the water-cooled cable current detection unit 2 is ringed on the transformer short network 3.

[0097] The specific steps for diagnosing the water-cooling cable circuit breaker fault are as follows:

[0098] Step 1: Collect water-cooled cable status data

[0099] In the normal state of the water-cooled cable during the production process, the fault diagnosis detector 1 synchronously collects the state data of the first water-cooled cable and the second water-cooled cable through the water-cooled cable current detection 2, the first water-cooled cable cooling water return water temperature detection unit 8, the first water-cooled cable cooling water return water flow detection unit 10, the second water-cooled cable cooling water return water temperature detection unit 9, and the second water-cooled cable cooling water return water flow detection unit 11 to establish a water-cooled cable temperature model under normal conditions;

[0100] Step 2: Establish a water-cooled cable temperature model

[0101] During the production process, the status of the water-cooled cable is monitored in real time, and the current detection data is brought into the established water-cooled cable temperature model to calculate the temperature T of the water-cooled cable in normal state. m ;

[0102] Step 2: Calculate the T output of the cooling water temperature model for water-cooled cables m The difference T between the actual water-cooled cable cooling water detection temperature T e =T-T m ;

[0103] Step 3: When T e ﹥Maximum allowable temperature deviation T α , then the number of determinations δ = δ + 1, otherwise, δ = 0, and return to step 2.

[0104] Step 4: When the number of determinations δ> the maximum allowable deviation number n, it is determined that the water-cooling cable is broken.

[0105] This method can be used to accurately diagnose faulty water-cooling cables, which reduces the difficulty of troubleshooting water-cooling cable faults during actual equipment maintenance, shortens the water-cooling cable fault recovery time, and provides a strong guarantee for the stable operation of the entire production line.

[0106] Where: T m Output temperature for the cooling water temperature model of water-cooled cables;

[0107] T is the actual return water temperature of the cooling water for the water-cooled cable;

[0108] T e The temperature difference between the actual water-cooled cable cooling water return temperature and the water-cooled cable cooling water temperature model output;

[0109] T α is the maximum allowable temperature deviation;

[0110] δ is the number of judgments;

[0111] n is the maximum number of deviations allowed.

[0112] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0113] In the absence of conflicts, technicians in this field can combine the relevant technical features in the above examples according to actual conditions to achieve corresponding technical effects. The specific combinations are not described here one by one.

[0114] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0115] The above are only preferred embodiments of the present invention. The present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A LF furnace water-cooling cable circuit breaker fault diagnosis system, comprising at least a transformer short circuit network (3), two water-cooling cables and two water-cooling cable cooling water return pipes, each water-cooling cable is connected to one water-cooling cable cooling water return pipe, and the two water-cooling cables are respectively connected to the transformer short circuit network (3); characterized in that: It also includes a fault diagnosis detector (1), two water-cooled cable cooling water return flow detection units, two water-cooled cable cooling water return temperature detection units and a water-cooled cable current detection unit (2); each water-cooled cable cooling water return pipe is respectively connected to a water-cooled cable cooling water return flow detection unit and a water-cooled cable cooling water return temperature detection unit, and the water-cooled cable current detection unit (2) is looped on the transformer short network (3); the fault diagnosis detector (1) is respectively connected to the two water-cooled cable cooling water return flow detection units, the two water-cooled cable cooling water return temperature detection units and the water-cooled cable current detection unit (2) by electrical signals; The fault diagnosis detector (1) at least comprises a receiving module, a computing module, an output module and a display module; the receiving module is respectively connected to the two-way water-cooling cable cooling water return flow detection unit, the two-way water-cooling cable cooling water return temperature detection unit and the water-cooling cable current detection unit (2) by electrical signals, and is used to receive the current data on the transformer short network (3) and the return flow and return temperature data of the two-way water-cooling cable cooling water return pipes; the computing module is used to establish a water-cooling pipe cable cooling water temperature model according to the acquired water-cooling pipe cable state data, and to calculate the deviation between the acquired real-time data and the water-cooling pipe cable cooling water temperature model; when the deviation value reaches a set threshold value, the water-cooling cable is determined to be a water-cooling cable with a broken circuit fault; the output module is used to output the computing result of the computing module to the display module to display the water-cooling cable broken circuit fault judgment result; The water-cooled cable temperature prediction model established by the water-cooled cable cooling water temperature model is as follows: in: for The return flow rate of cooling water for water-cooled cables at all times; for The current flowing through the water-cooling cable at all times; for The return water temperature of water-cooled cables at all times; for The return water temperature of water-cooled cables at all times; Nonlinear mapping for neural network structure and parameter determination.

2. A LF furnace water-cooling cable circuit breaker fault diagnosis system as claimed in claim 1, characterized in that: The water-cooled cable cooling water return flow detection unit is composed of an electromagnetic flowmeter.

3. A LF furnace water-cooling cable circuit breaker fault diagnosis system as claimed in claim 1, characterized in that: The water-cooled cable current detection unit (2) is composed of a Rogowski coil sensor.

4. A LF furnace water-cooling cable circuit breaker fault diagnosis system as claimed in claim 1, characterized in that: The water-cooled cable cooling water return temperature detection unit is composed of a PT100 temperature sensor.

5. A method for diagnosing a LF furnace water-cooling cable circuit breaker fault, characterized in that: A LF furnace water-cooling cable circuit breaker fault diagnosis system as claimed in any one of claims 1 to 4 is used, comprising the following steps: Step 1: The fault diagnosis detector (1) obtains the actual current, actual return water flow rate and actual return water temperature data of the water-cooling cable under normal conditions; Step 2: The fault diagnosis detector (1) establishes a cooling water temperature model of the water-cooled cable according to the normal state data of the water-cooled cable obtained in step 1; Step 3: The fault diagnosis detector (1) obtains the water-cooling cable status data in real time and compares it with the cooling water temperature model of the water-cooling cable. When the water-cooling cable has a short circuit fault, its real-time status data deviates from the temperature model. When the deviation value reaches a set threshold, the water-cooling cable is determined to be a short circuit fault water-cooling cable.

6. A method for diagnosing a LF furnace water-cooling cable circuit breaker fault as claimed in claim 5, characterized in that: The specific method for establishing the cooling water temperature model of the water-cooled cable is as follows: Step 1: Establish a BP neural network with a 3-8-1 network structure and initialize the neural network weights W and bias value b; Step 2: Select n groups of input samples X and expected output T obtained in actual production as network training samples and perform normalization in: The return flow rate of cooling water for water-cooled cables Sample values; The water-cooled cable current Sample values; The return water temperature of the cooling water for the water-cooled cable Sample values; i is the number of samples; Step 3: Send the normalized data into the network for training with a learning rate of 0.

01. When the expected error is less than 10-8, stop training the network and complete the establishment of the water-cooled cable temperature prediction model.

7. A method for diagnosing a LF furnace water-cooling cable circuit breaker fault as claimed in claim 5, characterized in that: The specific method of the fault diagnosis detector (1) in step 3 to obtain the water-cooled cable status data in real time and compare it with the water-cooled cable cooling water temperature model is as follows: Step 1: Calculate the temperature Tm of the water-cooled cable under normal conditions according to the water-cooled cable cooling water temperature model established in step 2; Step 2: Calculate the difference between Tm output by the water-cooled cable cooling water temperature model and the actual water-cooled cable cooling water detection temperature T, Te = T-Tm; Step 3: When Te> the maximum allowable temperature deviation Tα, the number of determinations δ=δ+1, otherwise, δ=0, and return to step 2; Step 4: When the number of determinations δ> the maximum allowable deviation number n, it is determined that the water-cooling cable is broken; Where: Tm is the output temperature of the cooling water temperature model of the water-cooled cable; T is the actual return water temperature of the cooling water for the water-cooled cable; Te is the temperature difference between the actual return water temperature of the water-cooled cable cooling water and the output temperature of the water-cooled cable cooling water temperature model; Tα is the maximum allowable temperature deviation; δ is the number of judgments; n is the maximum number of deviations allowed.

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