Mining low-voltage protection override trip prevention system and method

Abstract

The invention discloses a mining low-voltage protection override trip prevention system and a mining low-voltage protection override trip prevention method. A low-cost CAN bus is used as a communication network, self-negotiation networking is realized, and the system and the method are simple, reliable and easy to maintain; the main switch equipment calls the information of the branch switch equipment at regular time, and stops calling when the fault mutation is detected or a blocking signal is received, so that the network flow when the fault occurs is reduced, and the bus communication conflict is reduced; quick-break protection and electric leakage protection override trip prevention systems are realized in the same network, and the system has general applicability to coal mine low-voltage protection; a transient algorithm is only used for blocking signal detection and is not used as a protection exit algorithm, so that the reliability of leakage protection is improved; the main switch equipment and the branch switch equipment adopt different earth leakage protection action principles, so that the usability and the reliability of ground fault override trip prevention are ensured; whole-line delay-free quick action of different protection types can be realized, delay cooperation of upper and lower levels of traditional protection is not needed, and the method has positive significance in construction of a safe and stable power grid.

Description

Technical Field

[0001] The invention belongs to the technical field of power systems, and in particular relates to a system and method for preventing over-tripping of low-voltage protection for mines. Background Art

[0002] The anti-over-tripping system is a system in which the upper and lower protection levels interact with each other through information. When a fault occurs within the range of the lower protection level, the lower protection level will lock the upper protection level for a short time, and the upper protection level will not over-trip, thereby ensuring the selectivity of the protection action without sacrificing the rapidity of the upper protection action.

[0003] The anti-over-tripping system is a combination of traditional current protection and communication technology. It is established on the basis of comprehensive analysis of factors such as current, time, and network interoperability. It utilizes information interaction of the communication network and the upper and lower collaboration of protection devices in the area, so that the protection system can quickly locate and cut off the fault point, reduce the scope of power outage, and solve the contradiction between the rapidity and selectivity of relay protection. It has positive significance for improving the safety and reliability of coal mine power supply systems.

[0004] With the advancement of smart mine construction, coal mine 10kV power supply networks are generally equipped with anti-over-tripping systems. The current anti-over-tripping solution uses dedicated optical fiber or Ethernet communication, requires a dedicated communication server or switch, has a high construction cost, and is relatively complex to configure. The 1140 / 660V low-voltage power supply network has a simple topology, lacks a dedicated communication network, and has high cost requirements, which is not suitable for the current anti-over-tripping solution. Summary of the invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide a system and method for preventing over-tripping of low-voltage protection for mines, which is simple and reliable through self-negotiation networking through a low-cost CAN bus communication network. Without sacrificing the rapidity of the upper protection action, the selectivity of the protection action is guaranteed, and the rapid positioning and reliable isolation function of the quick-break protection and leakage protection are realized.

[0006] To achieve the above-mentioned purpose, the present invention provides a system for preventing over-tripping of low-voltage protection for mines, the system comprising a main switch device, multiple branch switch devices, a CAN bus communication network, and terminal resistors. The main switch device realizes trunk power supply line fault detection and removal and network topology management, the branch switch device realizes branch power supply line fault detection and removal, the CAN bus communication network is used for information transmission of the switch device, and the terminal resistor is used to eliminate network signal reflection and enhance anti-interference capability.

[0007] The present invention provides a method for preventing over-tripping of low-voltage protection for mines, comprising the following steps: Step 1: The switch device is connected to the CAN bus communication network; Step 2: The switch equipment performs auto-negotiation networking; Step 3, the main switch device periodically calls the branch switch device information; Step 4: The switch device detects sudden fault changes in real time; Step 5. When the branch switch device detects a sudden fault change, it immediately sends a locking signal. After the main switch device detects the protection fault, it receives the locking signal from the branch switch device and locks the protection outlet. The branch switch device successfully trips to remove the fault or the switch refusal to trip times out, and sends an unlocking signal, and the main switch device operates the outlet to remove the fault.

[0008] As an improvement of this solution, in step 2, the switching device performs auto-negotiation networking including the following steps: Step 2-1, the switch device is assigned a device number and a registration code, the main switch device number is initialized to 00, the branch switch device number is initialized to FF, and the registration code is generated by a random number; Step 2-2, the main switch device initializes the branch switch device list to be empty, does not actively send a call message, the branch switch device does not receive a call message for 5 seconds, and sends a heartbeat message every 1 second. The heartbeat message contains its device number and registration code; Step 2-3, the main switch device receives the heartbeat message of the branch switch device, determines and registers its device number, and replies with the device number and registration code of the branch switch device; Step 2-4, the branch switch device receives the reply information of the main switch device, determines the device number assigned to it according to the registration code, and the branch switch device no longer actively sends a heartbeat message; Step 2-5: Repeat steps 2-3 and 2-4. All branch switch devices are registered by the main switch device, and the main switch device manages the branch switch device list.

[0009] As an improvement of the present solution, in step 3, the method for the main switch device to periodically call the branch switch device information is: according to the registered branch switch device list, the main switch device calls a branch switch device information every 100 milliseconds, and the main switch device detects a sudden fault or receives a locking signal to stop the periodic calling.

[0010] As an improvement of this solution, the calling message identifier is 7FF, and the blocking message identifier is 000. When a message conflict occurs, the blocking message takes priority to occupy the communication network, thereby improving communication reliability and real-time performance.

[0011] As an improvement of this solution, the rapid trip protection fault mutation detection adopts a floating threshold with a base value: 4-11, Mutations were detected when is the rated current, To remove the real-time calculation current of the mutation point, Startup due to current mutation. , To calculate the sampling data sequence number, is the current sampling point number, is the number of sampling points per cycle; 4-12. Update Compute data buffer, updated to when no mutation is detected , updated to ; 4-13. Sudden changes in sampling data are detected at three consecutive points, which are determined to be sudden changes in quick-break protection faults.

[0012] As an improvement of this solution, the leakage protection fault mutation detection method is: 4-21, Sampling mutations are detected when is the rated zero-sequence current, It is started by the sudden change of zero-sequence current. , the sampling data mutation is detected at three consecutive points, it is determined to be a zero-sequence current fault mutation, and the sampling point number is recorded ; 4-22, Mutations were detected when is the rated zero-sequence voltage, It is started by zero-sequence voltage mutation. , the sampling data mutation is detected at three consecutive points, it is determined to be a zero-sequence voltage fault mutation, and the sampling point number is recorded ; 4-23, starting sequence number from data window First, take the zero-sequence current and zero-sequence voltage half-cycle data, and calculate the correlation between the zero-sequence voltage derivative and the zero-sequence current based on the least squares method. ; 4-24, It is determined to be a sudden change in leakage protection fault.

[0013] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, any one of the methods for preventing over-tripping of low-voltage protection for mines is implemented.

[0014] A computer-readable storage medium stores computer instructions, which, when executed by a processor, implement a method for preventing over-tripping of low-voltage protection for mines.

[0015] Among them, the transient algorithm is only used for locking signal detection and is not used as a protection exit algorithm, which improves the reliability of leakage protection.

[0016] The main switchgear and branch switchgear adopt different leakage protection action principles: the main switchgear adopts leakage protection based on the additional DC source principle, and the branch switchgear adopts selective leakage protection based on zero-sequence admittance.

[0017] Compared with the prior art, the advantages of the present invention are as follows: the present invention uses a low-cost CAN bus as a communication network, self-negotiating networking, simple and reliable, and easy to maintain; the calling and locking messages have different priorities, and when a message conflict occurs, the locking message takes priority to occupy the communication network, thereby improving communication reliability and real-time performance; no configuration is required, and it automatically adapts to changes in the power supply network topology; the main switch device periodically calls the branch switch device information, and stops calling when a fault mutation is detected or a locking signal is received, thereby reducing network traffic when a fault occurs and reducing bus communication conflicts; fault mutations are detected in real time through changes in fault components, and a floating threshold with a base value improves the reliability and sensitivity of fault detection; a transient algorithm is used Detect sudden fault changes and realize real-time locking of leakage protection. The transient algorithm is only used for locking signal detection and is not used as a protection exit algorithm, which improves the reliability of leakage protection. The same network realizes quick-break protection and leakage protection anti-overtripping system, which is generally applicable to low-voltage protection in coal mines. The main switchgear and branch switchgear adopt different leakage protection action principles to ensure the ease of use and reliability of ground fault anti-overtripping. The zero-sequence transient direction eliminates the disturbance caused by noise and improves the rapidity and anti-interference ability of the ground fault algorithm. It can realize full-line fast action without delay for different protection types, and does not require the delay coordination of traditional protection upper and lower levels, which is of positive significance to building a safe and stable power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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 or the description of the prior art 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.

[0019] Figure 1 It is a schematic diagram of the process structure of the present invention; Figure 2 This is a reference diagram of the anti-over-tripping system of Example 1 of the present invention. DETAILED DESCRIPTION

[0020] The following descriptions of the embodiments refer to the accompanying drawings to illustrate specific embodiments in which the present invention may be implemented.

[0021] Example 1: Please refer to Figure 1 and Figure 2 As shown, Embodiment 1 of the present invention provides a system for preventing over-tripping of low-voltage protection for mining, comprising a main switch device KG1, four branch switch devices KG2~KG5, a CAN bus communication network, and terminal resistors. The main switch device KG1 realizes main power supply line fault detection and removal and network topology management, the branch switch devices KG2~KG5 realize branch power supply line fault detection and removal, the CAN bus communication network is used for information transmission of the switch devices, and the terminal resistors are used to eliminate network signal reflections and enhance anti-interference capabilities.

[0022] The main switch device KG1 and the four branch switch devices KG2~KG5 are connected to the CAN bus communication network and perform self-negotiation networking after normal operation. The device number of KG1 is initialized to 00, and the device numbers of KG2~KG5 are initialized to FF. The registration code is generated by the random number of the device. It is assumed that the generated registration code KG1 is 11, KG2 is 22, KG3 is 33, KG4 is 44, and KG5 is 55. KG1 initializes the branch switch device list to be empty and does not actively send a call message. When KG2~KG5 does not receive a call message within 5 seconds, they send a heartbeat message every 1 second. The heartbeat message contains its device number FF and a random number registration code. KG1 receives the heartbeat message from KG2~KG5, determines and registers its KG2~KG5 device numbers as 1~4, and replies with KG2~KG5 device numbers 1~4 and registration codes 22~55 respectively. KG2~KG5 receives KG1's reply information, determines its assigned device number based on the registration code, and no longer actively sends heartbeat messages. KG2~KG5 are successfully registered by KG1. KG1 manages the KG2~KG5 list and summons a branch switch device information every 100 milliseconds.

[0023] When a fault occurs in the KG3 branch line, both the branch switch device KG3 and the main switch device KG1 detect a sudden fault. KG1 detects a sudden fault and stops the timed call. KG3 detects a sudden fault and immediately sends a locking signal. KG1 receives the locking signal from KG3 and locks the protection outlet. KG3 trips successfully to cut off the fault or the switch refusal to trip times out and sends an unlocking signal, and KG1 operates the outlet to cut off the fault.

[0024] Example 2: Please refer to Figure 1 and Figure 2 As shown, a method for performing over-tripping protection using a low-voltage protection over-tripping protection system for mines comprises the following steps: Step 1: The switch device is connected to the CAN bus communication network; Step 2: The switch equipment performs auto-negotiation networking; Step 3, the main switch device periodically calls the branch switch device information; Step 4: The switch device detects sudden fault changes in real time; Step 5. When the branch switch device detects a sudden fault change, it immediately sends a locking signal. After the main switch device detects the protection fault, it receives the locking signal from the branch switch device and locks the protection outlet. The branch switch device successfully trips to remove the fault or the switch refusal to trip times out, and sends an unlocking signal, and the main switch device operates the outlet to remove the fault.

[0025] Among them, in step 2, the switch device performs auto-negotiation networking including the following steps: Step 2-1, the switch device is assigned a device number and a registration code, the main switch device number is initialized to 00, the branch switch device number is initialized to FF, and the registration code is generated by a random number; Step 2-2, the main switch device initializes the branch switch device list to be empty, does not actively send a call message, the branch switch device does not receive a call message for 5 seconds, and sends a heartbeat message every 1 second. The heartbeat message contains its device number and registration code; Step 2-3, the main switch device receives the heartbeat message of the branch switch device, determines and registers its device number, and replies with the device number and registration code of the branch switch device; Step 2-4, the branch switch device receives the reply information of the main switch device, determines the device number assigned to it according to the registration code, and the branch switch device no longer actively sends a heartbeat message; Step 2-5: Repeat steps 2-3 and 2-4. All branch switch devices are registered by the main switch device, and the main switch device manages the branch switch device list.

[0026] In step 3, the method for the main switch device to periodically call the branch switch device information is: according to the registered branch switch device list, the main switch device calls a branch switch device information every 100 milliseconds, and the main switch device stops the periodic calling when it detects a sudden fault or receives a locking signal.

[0027] The calling message identifier is 7FF, and the blocking message identifier is 000. When a message conflict occurs, the blocking message takes priority in occupying the communication network, thereby improving communication reliability and real-time performance.

[0028] The detection of sudden fault changes in quick-break protection uses a floating threshold with a base value. The specific steps are as follows: 4-11, Mutations were detected when is the rated current, To remove the real-time calculation current of the mutation point, Startup due to current mutation. , To calculate the sampling data sequence number, is the current sampling point number, is the number of sampling points per cycle; 4-12. Update Compute data buffer, updated to when no mutation is detected , updated to ; 4-13. Sudden changes in sampling data are detected at three consecutive points, which are determined to be sudden changes in quick-break protection faults.

[0029] Among them, the leakage protection fault mutation detection, the specific steps are as follows: 4-21, Sampling mutations are detected when is the rated zero-sequence current, It is started by the sudden change of zero-sequence current. , the sampling data mutation is detected at three consecutive points, it is determined to be a zero-sequence current fault mutation, and the sampling point number is recorded ; 4-22, Mutations were detected when is the rated zero-sequence voltage, It is started by zero-sequence voltage mutation. , the sampling data mutation is detected at three consecutive points, it is determined to be a zero-sequence voltage fault mutation, and the sampling point number is recorded ; 4-23, starting sequence number from data window First, take the zero-sequence current and zero-sequence voltage half-cycle data, and calculate the correlation between the zero-sequence voltage derivative and the zero-sequence current based on the least squares method. ; 4-24, It is determined to be a sudden change in leakage protection fault.

[0030] The transient algorithm is only used for blocking signal detection and is not used as a protection exit algorithm, which improves the reliability of leakage protection.

[0031] The main switchgear and branch switchgear adopt different leakage protection action principles: the main switchgear adopts leakage protection based on the principle of additional DC source, and the branch switchgear adopts selective leakage protection based on zero-sequence admittance.

[0032] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above technical features.

Claims

1. A system for preventing over-level tripping of low-voltage protection for mines, characterized in that: The system includes a main switch device, multiple branch switch devices, a CAN bus communication network and terminal resistors. The main switch device realizes trunk power supply line fault detection and removal and network topology management, the branch switch devices realize branch power supply line fault detection and removal, the CAN bus communication network is used for information transmission of the switch devices, and the terminal resistors are used to eliminate network signal reflections and enhance anti-interference capabilities.

2. A method for preventing over-tripping of low-voltage protection for mines, characterized in that: Using the system for preventing over-tripping of low-voltage protection for mines according to claim 1, the method comprises the following steps: Step 1: The switch device is connected to the CAN bus communication network; Step 2: The switch equipment performs auto-negotiation networking; Step 3, the main switch device periodically calls the branch switch device information; Step 4: The switch device detects sudden fault changes in real time; Step 5. When the branch switch device detects a sudden fault change, it immediately sends a locking signal. After the main switch device detects the protection fault, it receives the locking signal from the branch switch device and locks the protection outlet. The branch switch device successfully trips to remove the fault or the switch refusal to trip times out, and sends an unlocking signal, and the main switch device operates the outlet to remove the fault.

3. A method for preventing over-tripping of low-voltage protection for mines according to claim 2, characterized in that: In step 2, the switch device performs auto-negotiation networking including the following steps: Step 2-1, the switch device is assigned a device number and a registration code, the main switch device number is initialized to 00, the branch switch device number is initialized to FF, and the registration code is generated by a random number; Step 2-2, the main switch device initializes the branch switch device list to be empty, does not actively send a call message, the branch switch device does not receive a call message for 5 seconds, and sends a heartbeat message every 1 second. The heartbeat message contains its device number and registration code; Step 2-3, the main switch device receives the heartbeat message of the branch switch device, determines and registers its device number, and replies with the device number and registration code of the branch switch device; Step 2-4, the branch switch device receives the reply information of the main switch device, determines the device number assigned to it according to the registration code, and the branch switch device no longer actively sends a heartbeat message; Step 2-5: Repeat steps 2-3 and 2-4. All branch switch devices are registered by the main switch device, and the main switch device manages the branch switch device list.

4. A method for preventing over-tripping of low-voltage protection for mines according to claim 2, characterized in that: In step 3, the method for the main switch device to periodically call the branch switch device information is: according to the registered branch switch device list, the main switch device calls a branch switch device information every 100 milliseconds, and the main switch device stops the periodic calling when it detects a sudden fault or receives a locking signal.

5. A method for preventing over-tripping of low-voltage protection for mines according to claim 2, characterized in that: The detection of sudden fault changes in quick-break protection uses a floating threshold with a base value. The specific steps are as follows: 4-11, Mutations were detected when is the rated current, To remove the real-time calculation current of the mutation point, Startup due to current mutation. , To calculate the sampling data sequence number, is the current sampling point number, is the number of sampling points per cycle; 4-12. Update Compute data buffer, updated to when no mutation is detected , updated to ; Sudden changes in the sampling data were detected at three consecutive points and were determined to be sudden changes in the quick-break protection fault.

6. A method for preventing over-tripping of low-voltage protection for mines according to claim 2, characterized in that: The specific steps for detecting sudden change of leakage protection fault are as follows: 4-21, Sampling mutations are detected when is the rated zero-sequence current, It is started by the sudden change of zero-sequence current. , the sampling data mutation is detected at three consecutive points, it is determined to be a zero-sequence current fault mutation, and the sampling point number is recorded ; 4-22, Mutations were detected when is the rated zero-sequence voltage, It is started by zero-sequence voltage mutation. , the sampling data mutation is detected at three consecutive points, it is determined to be a zero-sequence voltage fault mutation, and the sampling point number is recorded ; 4-23, starting sequence number from data window First, take the zero-sequence current and zero-sequence voltage half-cycle data, and calculate the correlation between the zero-sequence voltage derivative and the zero-sequence current based on the least squares method. ; 4-24, It is determined to be a sudden change in leakage protection fault.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method for preventing over-tripping of low-voltage protection for mines as described in any one of claims 2 to 6 above is implemented.

8. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the computer instruction is executed by the processor, the method for preventing over-tripping of low-voltage protection for mines as described in any one of claims 2 to 6 is implemented.

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