Bus over-current protection configuration method and device for subway power supply system and medium

Abstract

The invention discloses a bus overcurrent protection configuration method and device for a subway power supply system and a medium, and the method comprises the steps: carrying out the real-time monitoring of a target detection line, obtaining the current working state information of the target detection line, and extracting a control word of the target detection line and a voltage value of the target detection line; judging whether re-voltage locking is needed or not according to the control word and the voltage value of the target detection line; if yes, bus voltage and bus current detection is carried out on the target detection line; determining whether the overcurrent protection action meets a starting condition or not according to the detection results of the bus voltage and the bus current; if the overcurrent protection action condition is met, inputting a protection state based on a control word, and sending a control starting protection state; and when the protection state is started, over-current protection is put into a set time threshold value. Line faults can be accurately detected, misoperation under the non-fault condition is avoided, a target line is instructed in time to correctly respond to fault conditions, and safety and stability of subway operation are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of power system protection, and in particular to a busbar overcurrent protection configuration method, equipment and medium for a subway power supply system. Background Art

[0002] To ensure the stable operation of subway lines, the accuracy and response speed of fault detection in the power supply system are crucial to the safe and stable operation of the system. For example, in the event of a short circuit or overload, the current will suddenly increase, which may cause the fault to expand and affect the stable operation of the power system. Overcurrent protection can cut off the power supply in time, protect the equipment from damage by overload current, and avoid economic losses and safety accidents caused by equipment damage. However, existing protection methods may have some limitations and cannot meet the needs of fast and accurate detection. The specific reasons are as follows:

[0003] Before taking protective action, the fault needs to be detected first. During the detection process, it is usually necessary to be based on pre-set thresholds and rules, and it is not flexible to adapt to the changes of various faults and the emergence of new faults. This rigidity limits its performance in improving the adaptability and robustness of the system. With the expansion of the scale of the power system and the increase in the amount of data, traditional methods may not be able to effectively process this large amount of information. Its calculation speed may be limited, thus affecting the accuracy and response speed of protective actions for faults. Traditional methods usually need to rely on the experience and knowledge of professionals to diagnose and predict faults, and require manual extraction and analysis of a large amount of data. The data processing and analysis process is cumbersome and prone to errors. In complex environments, traditional methods may show weak robustness and accuracy in fault detection and location tasks during line operation, such as the possibility of refusal to operate due to the controlled limitation of fault current, and there are misunderstandings in the setting value of the protection device, which leads to the inability of the protection device to respond correctly to fault conditions. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the traditional method is inaccurate in bus fault detection, resulting in the target device being unable to correctly respond to the fault. The purpose is to provide a bus overcurrent protection configuration method, device and medium for a subway power supply system. The device corresponding to the target detection line is accurately configured through control words, and different control words are set according to different protection requirements to achieve more flexible protection control, thereby achieving accurate fault detection. By detecting the voltage and current, it is ensured that the overcurrent protection will only be activated when both the voltage and current meet specific conditions, thereby avoiding false operation in non-fault conditions. Real-time detection of the bus voltage and current can ensure that the protection device has an accurate understanding of the system status, and can ensure that when a power supply system fails, it responds to the fault correctly, so that the faulty part can be cut off in time to avoid the expansion of the accident, thereby ensuring the safety and stability of the subway operation.

[0005] The present invention is achieved through the following technical solutions:

[0006] A first aspect of the present invention provides a method for configuring busbar overcurrent protection of a subway power supply system, comprising the following specific steps:

[0007] Monitor the target detection circuit in real time, obtain the current working status information of the target detection circuit, and extract the control word and voltage value of the target detection circuit;

[0008] Determine whether re-pressure locking is required through control word and target detection line voltage value;

[0009] If it is determined to be necessary, the bus voltage and bus current of the target detection circuit are detected;

[0010] Determine whether the overcurrent protection action meets the start condition according to the detection results of the bus voltage and bus current;

[0011] If the overcurrent protection action conditions are met, the protection state is put into operation based on the control word, and the control start protection state is sent;

[0012] When the protection state is started, overcurrent protection is activated within a set time threshold.

[0013] Further, judging whether re-pressure locking is required by using the control word and the target detection line voltage value specifically includes:

[0014] Analyze the control word to determine the current state of the re-pressure locking function;

[0015] Extract the bit used to set the re-pressure locking function in the control word, modify the bit used to set the re-pressure locking function to start and stop the re-pressure locking.

[0016] Furthermore, the bus voltage and bus current of the target detection line are detected, specifically including:

[0017] Obtain the real-time value of the bus three-phase voltage and perform bus PT disconnection detection and bus PT reverse sequence detection;

[0018] Obtain the real-time value of the bus three-phase current and perform bus CT break detection and bus CT reverse sequence detection.

[0019] Furthermore, the bus PT disconnection detection includes:

[0020] The device determines whether the busbar is disconnected through the PT disconnection self-detection control word, including:

[0021] Detect bus maximum line voltage and bus negative sequence voltage;

[0022] If the above conditions meet the set threshold, it is detected as a PT disconnection.

[0023] Furthermore, the bus PT reverse sequence detection includes:

[0024] The busbar reverse sequence is determined by the PT line break self-check control word throw and drop, including:

[0025] If the negative sequence voltage is greater than the positive sequence voltage of the set threshold and the negative sequence voltage is greater than the set threshold, the PT reverse sequence is detected when the conditions are met.

[0026] Furthermore, the bus current detection includes:

[0027] When the device determines that the negative sequence current is greater than the set rated current and greater than the set positive sequence current, it is detected as CT reverse sequence;

[0028] When the negative sequence voltage of the system bus is less than the set voltage, the maximum phase current is greater than the set rated current, and the current of any phase of the system bus is less than the set rated current, it is detected as a CT disconnection;

[0029] When the measured current of any phase of the system bus is less than the set rated current, and the measured zero-sequence current and negative-sequence current are greater than the set rated current, it is detected as a CT break.

[0030] Further, the protection state is started by controlling the word, specifically including:

[0031] Set the overcurrent protection of the target protection device from stage I to stage III, and activate or deactivate the overcurrent stages I to III through the control word;

[0032] Setting a specific bit in the control word to 1 enables the protection, and setting a specific bit in the control word to 0 disables the protection.

[0033] Furthermore, when the protection state is started by the control word, the overcurrent inverse time protection is set by the control word, and the overcurrent inverse time protection includes:

[0034] General inverse time limit:

[0035]

[0036] Very anti-time limit:

[0037]

[0038] Extreme Inverse Time:

[0039]

[0040] Among them, I represents the actual current, I p is the current reference value, t pis the time constant, and t represents the calculated exit time limit.

[0041] A second aspect of the present invention provides 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, a bus overcurrent protection configuration method for a subway power supply system is implemented.

[0042] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for configuring bus overcurrent protection of a subway power supply system.

[0043] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0044] The control word is used to accurately configure the device corresponding to the target detection line, and different control words are set for different protection requirements to achieve more flexible protection control, thereby achieving accurate fault detection. By detecting the voltage and current, it is ensured that the overcurrent protection will only be activated when both the voltage and current meet specific conditions, thereby avoiding false operation in non-fault conditions. Real-time detection of bus voltage and current can ensure that the protection device has an accurate understanding of the system status, and can ensure that when a power supply system fails, it can respond to the fault correctly, so that the faulty part can be cut off in time to avoid the expansion of the accident, thereby ensuring the safety and stability of the subway operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0046] Figure 1 The protection configuration process of the subway medium voltage power supply system in the embodiment of the present invention;

[0047] Figure 2 The overcurrent protection action startup process in the embodiment of the present invention;

[0048] Figure 3 This is the overcurrent inverse time protection action startup process in the embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0050] As a possible implementation, Figure 1 As shown, this embodiment provides a bus overcurrent protection configuration method for a subway power supply system, comprising the following specific steps: real-time monitoring of a target detection line, obtaining current working status information of the target detection line, extracting a control word of the target detection line and a voltage value of the target detection line; judging whether re-pressure locking is required through the control word and the voltage value of the target detection line; if it is determined to be required, detecting the bus voltage and bus current of the target detection line; determining whether the overcurrent protection action meets the start condition according to the detection results of the bus voltage and the bus current; if the overcurrent protection action condition is met, putting the protection state into operation based on the control word, and sending a control to start the protection state; when the protection state is started, putting the overcurrent protection into operation within a set time threshold. In this embodiment, the device corresponding to the target detection line is accurately configured through the control word, and different control words can be set for different protection requirements, such as putting in or out of a specific protection function, to achieve more flexible protection control, and to ensure that the overcurrent protection will only be activated when both the voltage and current meet specific conditions, thereby avoiding false operation in non-fault conditions. Real-time detection of the bus voltage and current can ensure that the protection device has an accurate understanding of the system status, so that the action of the protection device can be accurately controlled when a fault occurs, which can reduce unnecessary power outages caused by false operation and ensure the continuity of power supply. When the overcurrent protection action conditions are met, the protection device can be quickly activated within the set time threshold, quickly cut off the faulty part, reduce the impact of the fault on the system, and improve the safety, reliability and stability of the power system.

[0051] In some possible implementations, the use of a control word to select whether to lock through re-pressure locking through voltage is a commonly used technical means in power system relay protection, the purpose of which is to improve the accuracy and reliability of protection, wherein the control word is a set of binary codes used to control and adjust specific functions of the protection device. In the relay protection device, each bit of the control word corresponds to a different setting option. The re-pressure locking is a protection mechanism that ensures that the overcurrent protection will only operate when the voltage drops below a certain level. This can prevent false operation due to an increase in instantaneous current under normal voltage conditions. Therefore, through a specific bit in the control word, it can be selected whether to enable the re-pressure locking function. If enabled, the protection device will require that the voltage also meets certain conditions (such as being lower than a certain threshold) to enable the overcurrent protection to operate. Under this setting condition, the selectivity of the protection can be improved, ensuring that the protection device will only operate under real fault conditions, thereby avoiding unnecessary power outages and equipment damage.

[0052] In some possible implementations, the detection of the bus voltage and bus current of the target detection circuit specifically includes:

[0053] Obtain the real-time value of the bus three-phase voltage and perform bus PT disconnection detection and bus PT reverse sequence detection;

[0054] Obtain the real-time value of the bus three-phase current and perform bus CT break detection and bus CT reverse sequence detection.

[0055] Bus PT disconnection detection includes: the device determines bus disconnection by switching on and off the "PT disconnection self-check" control word, and the judgment criteria are as follows:

[0056] 1) Maximum bus line voltage Less than 18V, and the switch is in the closed position or there is current in the circuit;

[0057] 2) Bus negative sequence U2 is greater than 6V;

[0058] If any of the above conditions is met, the device will report "PT disconnection" with a delay of 10 seconds. If all the above judgment conditions are met, the alarm will be returned with a delay of 2 seconds.

[0059] After the PT line is disconnected, the overcurrent protection for determining direction or re-pressure conditions will be immediately exited.

[0060] b. Bus PT reverse sequence

[0061] The device determines the busbar reverse sequence by the "PT line break self-check" control word throw and withdraw, the judgment criteria are as follows:

[0062] If the negative sequence voltage is greater than 4 times the positive sequence voltage and the negative sequence voltage is greater than 12V, the device will report "PT reverse sequence" after a delay of 10s when the conditions are met. After the above judgment conditions are returned, the alarm will be returned after a delay of 2s.

[0063] The device determines whether the bus is broken through the PT line break self-check control word throw and withdraw, detects the bus maximum line voltage, bus negative sequence voltage, the switch is in the closed position or the current of the line

[0064] If the above conditions meet the set threshold, it is detected as a PT disconnection.

[0065] Bus current detection includes:

[0066] CT reverse sequence: When the device determines that the negative sequence current is greater than 0.04 times the rated current and greater than 4 times the positive sequence current, the device will delay 10s to report the "CT reverse sequence" alarm. If the above conditions are not met, the alarm will be returned after a delay of 2s.

[0067] CT disconnection: When the negative sequence voltage of the system bus is less than 4V, the maximum phase current is greater than 0.1 times the rated current, and any phase current is less than 0.04 times the rated current, the device will delay 10s to report the "CT disconnection" alarm. If the above conditions are not met, the alarm will return after a delay of 2s.

[0068] CT disconnection: If the current measured in any phase is less than 0.005 times the rated current, and the zero-sequence current and negative-sequence current are greater than 0.1 times the rated current, the device will report the "CT disconnection" alarm after a delay of 10 seconds. If the above conditions are not met, the alarm will be returned after a delay of 2 seconds.

[0069] In the power system, bus PT (voltage transformer) disconnection, bus PT reversal, bus CT (current transformer) disconnection and bus CT reversal are important conditions that affect the overcurrent protection action. The following are steps on how to determine whether these conditions meet the overcurrent protection action conditions:

[0070] For bus PT disconnection, that is, any one or more phases of the bus three-phase voltage suddenly drops to zero or close to zero, while the other two phases are normal, if the PT disconnection is detected, the overcurrent protection will usually be locked to prevent malfunction caused by voltage loss. This locking function needs to be implemented through control words or protection logic.

[0071] For bus PT reverse sequence, that is, the phase order of the three-phase voltage is incorrect, it can be detected by comparing the phase angles of the three-phase voltage. PT reverse sequence may affect the judgment of directional protection. Therefore, it is necessary to ensure that in the case of PT reverse sequence, the relevant directional overcurrent protection is locked or exited.

[0072] In the case of bus CT break, the current of one phase or multiple phases suddenly drops to zero or close to zero, while the currents of other phases are normal, or the negative sequence current and zero sequence current are abnormal. The CT break may affect the accuracy of the overcurrent protection. Therefore, in the case of CT break, the relevant overcurrent protection may need to be locked until the CT returns to normal.

[0073] For bus CT reverse sequence, that is, the phase order of the three-phase current is incorrect, it can be detected by comparing the phase angles of the three-phase current. CT reverse sequence may affect the judgment of directional protection. Therefore, it is necessary to ensure that in the case of CT reverse sequence, the relevant directional overcurrent protection is locked or exited.

[0074] like Figure 2As shown in the figure, in the power system protection, the control word is used to set some control modes of the protection device. They can control the protection function, operation mode and the input or output of the protection parameters. According to the operation status and protection requirements of the power system, determine the protection function that needs to be put into or out. Set the corresponding control word in the setting list of the protection device. Each bit of the control word corresponds to a specific protection function, which is put into or out by setting it to 1 or 0. The soft pressure plate is a function in the protection device, and the protection function can be put into or out by operating the soft pressure plate. The soft pressure plate and the hard pressure plate form an AND gate relationship. Only when both are put into, the protection is put into. After the control word and the soft pressure plate are set, it is necessary to confirm whether the protection state has been put into or out as expected. After the protection function is put into, the corresponding test is carried out to ensure that the protection function can respond to the system fault correctly. The setting of the control word and the change of the protection state are recorded for future maintenance and audit. The output of the control word is not necessarily tripped. The control word is just the operation mode of the protection or unified automatic device set by the dispatcher combined with the power grid. For example, the control word of the automatic reclosing operation mode has two options: synchronization check and no-pressure check, and not all of them have outputs. Therefore, starting the protection state through the control word is a process involving multiple steps and confirmation links, which needs to be strictly implemented in accordance with the operating procedures to ensure the safe and stable operation of the power system. Among them,

[0075] The protection state is activated by the control word. Specifically, the device is equipped with overcurrent protection of stages I to III, which can be activated and deactivated respectively by the control word. The overcurrent element is installed according to the phase, and the control word "overcurrent n stages through voltage" (n = I, II, III) can be used to select whether to be locked by re-pressure. When the bus PT is disconnected, the overcurrent protection with voltage function will automatically exit. The overcurrent protection action criterion is:

[0076] 1) Overcurrent protection input: overcurrent n stage input;

[0077] 2) The overcurrent n-segment X-phase current satisfies: X-phase current I Φ >I setn (I Φ is the phase current, I setn is the overcurrent n-stage constant, X=A, B, C);

[0078] 3) The re-voltage opening meets the following conditions: when any line voltage value is lower than the overcurrent low voltage setting value or the negative sequence voltage is greater than the overcurrent negative sequence voltage setting value, the overcurrent protection is opened; otherwise, the overcurrent protection is locked.

[0079] like Figure 3 As shown, when the protection state is started by the control word, the overcurrent inverse time protection is also set by the control word. The overcurrent inverse time protection includes:

[0080] General inverse time limit:

[0081]

[0082] Very anti-time limit:

[0083]

[0084] Extreme Inverse Time:

[0085]

[0086] Among them, I represents the actual current, I p is the current reference value, t p is the time constant, and t represents the calculated exit time limit.

[0087] As a possible implementation method, this embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, a bus overcurrent protection configuration method for a subway power supply system is implemented.

[0088] As a possible implementation, this embodiment provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, a bus overcurrent protection configuration method for a subway power supply system is implemented.

[0089] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for configuring busbar overcurrent protection of a subway power supply system, characterized in that: The specific steps include: Monitor the target detection circuit in real time, obtain the current working status information of the target detection circuit, and extract the control word and voltage value of the target detection circuit; Determine whether re-pressure locking is required through control word and target detection line voltage value; If it is determined to be necessary, the bus voltage and bus current of the target detection circuit are detected; Determine whether the overcurrent protection action meets the start condition according to the detection results of the bus voltage and bus current; If the overcurrent protection action conditions are met, the protection state is put into operation based on the control word, and the control start protection state is sent; When the protection state is started, overcurrent protection is activated within a set time threshold.

2. The busbar overcurrent protection configuration method of the subway power supply system according to claim 1 is characterized in that: The determining whether re-pressure locking is required by using the control word and the target detection line voltage value specifically includes: Analyze the control word to determine the current state of the re-pressure locking function; Extract the bit used to set the re-pressure locking function in the control word, modify the bit used to set the re-pressure locking function to start and stop the re-pressure locking.

3. The busbar overcurrent protection configuration method of the subway power supply system according to claim 1 is characterized in that: The bus voltage and bus current of the target detection line are detected, including: Obtain the real-time value of the bus three-phase voltage and perform bus PT disconnection detection and bus PT reverse sequence detection; Obtain the real-time value of the bus three-phase current and perform bus CT break detection and bus CT reverse sequence detection.

4. The busbar overcurrent protection configuration method of the subway power supply system according to claim 3 is characterized in that: The busbar PT disconnection detection includes: The device determines whether the busbar is disconnected through the PT disconnection self-detection control word, including: Detect bus maximum line voltage and bus negative sequence voltage; If the above conditions meet the set threshold, it is detected as a PT disconnection.

5. The busbar overcurrent protection configuration method of the subway power supply system according to claim 3 is characterized in that: The bus PT reverse sequence detection includes: The busbar reverse sequence is determined by the PT line break self-check control word throw and drop, including: If the negative sequence voltage is greater than the positive sequence voltage of the set threshold and the negative sequence voltage is greater than the set threshold, the PT reverse sequence is detected when the conditions are met.

6. The busbar overcurrent protection configuration method of a subway power supply system according to claim 1, characterized in that: The bus current detection comprises: When the device determines that the negative sequence current is greater than the set rated current and greater than the set positive sequence current, it is detected as CT reverse sequence; When the negative sequence voltage of the system bus is less than the set voltage, the maximum phase current is greater than the set rated current, and the current of any phase of the system bus is less than the set rated current, it is detected as a CT disconnection; When the measured current of any phase of the system bus is less than the set rated current, and the measured zero-sequence current and negative-sequence current are greater than the set rated current, it is detected as a CT break.

7. The busbar overcurrent protection configuration method of a subway power supply system according to claim 1, characterized in that: The protection state is started by controlling the word to start and stop, specifically including: Set the overcurrent protection of the target protection device from stage I to stage III, and activate or deactivate the overcurrent stages I to III through the control word; Setting a specific bit in the control word to 1 enables the protection, and setting a specific bit in the control word to 0 disables the protection.

8. The busbar overcurrent protection configuration method of a subway power supply system according to claim 1, characterized in that: When the protection state is started by the control word, the overcurrent inverse time protection is also set by the control word. The overcurrent inverse time protection includes: General inverse time limit: Very anti-time limit: Extreme Inverse Time: Among them, I represents the actual current, I p is the current reference value, t p is the time constant, and t represents the calculated exit time limit.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the bus overcurrent protection configuration method of the subway power supply system as described in any one of claims 1 to 8 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the bus overcurrent protection configuration method of the subway power supply system as described in any one of claims 1 to 8 is implemented.

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