Direct current circuit breaker and mobile computing circuit breaker non-fault side current removing method

Abstract

The invention discloses a direct-current circuit breaker and a mobile computing circuit breaker non-fault side current clearing method, relates to the technical field of power electronics, and aims to solve the problem that the non-fault side current of a circuit cannot be quickly cleared in the prior art. The technical method provided by the invention comprises the step of introducing a mobile computing technology in a satellite network to solve the problem of eliminating non-fault-side current by a direct-current circuit breaker. On a satellite network, non-fault side current of each circuit breaker is calculated by using a mobile computing technology, and a clearing value of the non-fault side current is calculated. And then, transmitting the clearing value to the position of each circuit breaker, and carrying out current clearing through a control signal of the designed capacitor reusability direct current circuit breaker.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronics, and in particular relates to a direct current circuit breaker and a method for clearing current on a non-fault side of a mobile computing circuit breaker. Background Art

[0002] At present, with the continuous development of power electronics technology, DC circuit breakers are more and more widely used in power systems. The advantages of DC circuit breakers are that they can achieve fast disconnection and connection of switches, have higher switching frequency and better control performance, and can improve the stability and reliability of power systems. However, when using DC circuit breakers, due to various factors in the circuit, such as cable resistance, contact resistance, inductance, etc., non-fault side currents will be caused, thereby affecting the stability and reliability of the power system. Therefore, a method is needed to accurately calculate the non-fault side current and clear it to improve the safety and stability of the power system.

[0003] Mobile computing is an emerging computing method that distributes computing resources to multiple computing nodes for computing. The emergence of this computing method is mainly because the computing tasks faced in modern computer science are becoming more and more complex, requiring more powerful computing power to handle. The traditional centralized computing method, because computing resources are concentrated on a central node, is easily affected by the failure of the central node, causing the collapse of the entire system, and centralized computing takes a considerable amount of time to complete. Therefore, mobile computing is widely used in cloud computing, big data processing, high-performance computing and other fields, and has become a very popular research direction.

[0004] In view of the challenges and problems of current clearing on the non-fault side in power transmission projects, satellite network mobile computing and capacitor reuse DC circuit breakers are introduced. Satellite networks are considered as nodes for mobile computing to improve detection coverage and computing efficiency. The satellite network is only responsible for mobile computing to obtain current clearing values, and specific clearing control needs to be completed by DC circuit breakers. Since the satellite network is only responsible for mobile computing to obtain current clearing values, and specific clearing control needs to be completed by DC circuit breakers, a capacitor reuse DC circuit breaker is also designed to clear the non-fault side current according to the calculated clearing value. Summary of the invention

[0005] The present invention aims to solve the technical problem in the background technology that the non-fault current measurement of the circuit cannot be quickly cleared, and the purpose is to provide a DC circuit breaker and a mobile calculation circuit breaker non-fault side current clearing method, which can quickly calculate the non-fault side current and clear it.

[0006] In order to solve the technical problem, the technical solution of the present invention is:

[0007] Compared with the prior art, the advantages of the present invention are:

[0008] A satellite network-based mobile computing DC circuit breaker non-fault side current clearing method is proposed to improve the efficiency and accuracy of DC circuit breaker control. By introducing satellite network as a communication means, the shortcomings of traditional ground communication methods are overcome, especially the limitations in signal transmission stability and response speed.

[0009] Efficient data transmission and processing: High-speed and stable communication is achieved through satellite networks, avoiding the delay and instability of ground networks.

[0010] Intelligent control: Utilizing satellite nodes and mobile computing platforms, it is possible to quickly respond to faults and accurately control the operation of circuit breakers.

[0011] Energy-saving design: By rationally designing the current-carrying and transfer branches of the DC circuit breaker, the energy loss during operation is reduced and the overall energy efficiency of the system is improved.

[0012] This technology is suitable for wide-area power transmission systems, especially long-distance transmission lines. It can effectively improve the safety and stability of the system, while providing a more efficient solution for fault handling. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 , one A DC circuit breaker and a method for clearing current on the non-fault side of a mobile computing circuit breaker;

[0014] Figure 2 ,Sensor data collection, processing and transmission flow chart;

[0015] Figure 3 , calculation flow chart of clearing value of non-fault side current;

[0016] Figure 4 , a design structure diagram of a DC circuit breaker in the method;

[0017] Figure 5 , working flow diagram of the DC circuit breaker in this method. DETAILED DESCRIPTION

[0018] The specific implementation mode of the present invention is described below in conjunction with embodiments:

[0019] It should be noted that the structures, proportions, sizes, etc. shown in this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them, and are not used to limit the conditions under which the present invention can be implemented. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0020] At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0021] Embodiment 1:

[0022] The present invention provides a DC circuit breaker and a method for clearing current on the non-fault side of a mobile computing circuit breaker. Figure 1 The proposed satellite network mobile computing architecture for this method includes:

[0023] The satellite network mobile computing architecture includes multiple satellite network nodes and several DC circuit breakers on the power transmission network. There is a certain distance between each DC circuit breaker. As the distance of the power transmission line becomes longer and longer, the data on the DC circuit breaker will be transmitted to different nodes of the satellite network for mobile computing processing. This constitutes a satellite network mobile computing network.

[0024] In order to ensure the safety and reliability of the power system, DC circuit breakers need to be effectively controlled and positioned. Traditional DC circuit breaker control methods generally use ground communication methods, which have problems such as unstable signal transmission and slow response speed. In order to improve the control efficiency and accuracy of DC circuit breakers, it is a feasible method to use satellite networks to transmit the control signals of DC circuit breakers to the locations of each circuit breaker and locate the locations of each circuit breaker.

[0025] According to an embodiment of the present invention, a DC circuit breaker and a method for clearing current on a non-fault side of a mobile computing circuit breaker are provided.

[0026] Figure 2 The sensor data collection, processing and transmission process of this method includes:

[0027] Step 101, data collection

[0028] Specifically, determine the use environment and requirements of the current sensor on the transmission line, such as the measurement range, accuracy, sensitivity, etc., and select the appropriate type of current sensor. Select a suitable location on the transmission line to install the current sensor. Finally, perform data acquisition and record the data of the current sensor on the transmission line.

[0029] Step 102: Data processing

[0030] Specifically, the transmitted data is analyzed and processed to determine the performance indicators of the sensor data, such as accuracy, sensitivity, response time, etc., and calibrated or corrected. The data transmission process and data encryption method are designed to ensure the security and reliability of the sensor data.

[0031] Step 103: Data transmission

[0032] Specifically, appropriate satellite network nodes and transmission networks are selected to transmit the processed data to corresponding network nodes for mobile computing processing.

[0033] Figure 3 Calculate the cleared value of non-fault side current for mobile on satellite network.

[0034] Step 201, calculate short-circuit impedance

[0035] Specifically, it is necessary to calculate the short-circuit impedance in the power system. Short-circuit impedance refers to the ratio between the voltage and current at the short-circuit point when the power system is short-circuited, usually represented by the symbol Rsh. The short-circuit impedance can be obtained by the short-circuit impedance test of the power system. This test is usually conducted by the power company of the power system, and the test results can reflect the short-circuit impedance level of the power system.

[0036] Step 202, calculate the short circuit current

[0037] Specifically, it is necessary to calculate the short-circuit current in the power system. Short-circuit current refers to the maximum current at the short-circuit point when the power system is short-circuited, usually represented by the symbol Ish. The short-circuit current can be obtained through the short-circuit current test of the power system. This test is usually conducted by the power company of the power system, and the test results can reflect the short-circuit current level of the power system.

[0038] Step 203, calculate the clearing value of the non-fault side current

[0039] Specifically, the clearing value of the non-fault side current can be calculated using the following formula:

[0040] Cl=Rsh×Ish / (1+Rsh×Ish)

[0041] Where Cl represents the clearing value of the non-fault side current, Rsh represents the short-circuit impedance, and Ish represents the short-circuit current. This formula is used to calculate the clearing value of the non-fault side current, but it should be noted that this formula is only applicable to single-phase faults. In power systems, there are usually multi-phase faults, and the influence of phase impedance needs to be considered at this time.

[0042] Phase impedance refers to the resistance value between two phases in the power system, usually represented by the symbol Ralt. Phase impedance can reflect the phase short circuit situation in the power system. When calculating the phase impedance, we need to take into account the cables, generators, transformers and other equipment in the power system. The phase impedance of these equipment will affect the phase impedance, thereby affecting the clearing value of the non-fault side current.

[0043] Finally, the clearing value of the non-fault side current needs to be considered together with other factors in the power system to determine whether the power system can quickly return to normal operation.

[0044] Furthermore, current data collection specifically includes:

[0045] In the power system, the current sensor installed on the DC circuit breaker monitors the current data in the system, especially the current change when a short circuit occurs. The collected current data is mainly used to calculate the short-circuit current Ish.

[0046] In addition, the current sensor can also capture the voltage and impedance changes associated with the short-circuit fault, which helps in the subsequent calculation of the short-circuit resistance Rsh.

[0047] Calculate the short-circuit impedance Rsh:

[0048] The short-circuit impedance Rsh is the impedance value exhibited by the power system when it is short-circuited, which depends on factors such as the equipment configuration in the system, the location of the fault point, and the length of the line. This impedance value can be calculated by analyzing the data provided by the sensor (such as voltage and current waveforms).

[0049] Typically, the calculation of short-circuit impedance involves the rated parameters of the system, the distance to the fault point, and the voltage and current data collected by sensors during the fault period.

[0050] Calculate the short-circuit current Ish:

[0051] The short-circuit current Ish is the current flowing through the fault point when a short circuit occurs. The short-circuit current can be directly measured by a sensor and is a key data in the current clearance calculation.

[0052] The size of Ish directly affects the operational difficulty and strategy of clearing the non-fault side current.

[0053] Calculation of the clearing value of the non-fault side current:

[0054] After obtaining the short-circuit impedance Rsh and the short-circuit current Ish, the clearing value CL of the non-fault side current can be calculated using the formula:

[0055] CL=Rsh×Ish1+Rsh×Ish

[0056] This calculation process can be performed on a remote computing node connected to a satellite network. The node uses distributed computing methods to quickly process a large amount of data from different DC circuit breakers and calculate the non-fault side current clearing value of each circuit breaker.

[0057] Transfer Data:

[0058] After the data calculation is completed, the calculated clearing value CL will be transmitted to the control system of each DC circuit breaker via a satellite network or other communication methods.

[0059] The control systems of these circuit breakers automatically adjust operations based on the clearing values ​​received, such as triggering appropriate switches and components to perform actions to clear the current on the non-fault side.

[0060] Important information in data transmission:

[0061] Real-time current data: used to directly measure and calculate short-circuit current Ish.

[0062] Voltage and impedance information: These data are used to derive the system's short-circuit impedance, Rsh, which is an important parameter for calculating the clearing value.

[0063] Calculated clearing value CL: The calculated clearing value will be transmitted back to each circuit breaker through the communication network as an important control signal to trigger the circuit breaker operation.

[0064] Figure 4 This is the design structure diagram of the DC circuit breaker in this method, which can achieve the purpose of bidirectional current flow. It generally includes three parts: a current flow branch, a transfer branch and a bypass branch.

[0065] Specifically, the current-passing branch consists of a high-frequency mechanical switch UFD and an auxiliary commutation module ASM, which is mainly responsible for low-loss current during normal operation, and can achieve bidirectional current in the current-passing branch. The transfer branch includes a coupled negative voltage circuit and an energy-consuming branch, which mainly completes the transfer, suppression, removal and consumption of current during the fault. The bypass energy dissipation part is composed of a reverse-grounded thyristor T, which is mainly responsible for clearing the dissipation of the inductive current on the fault side.

[0066] Figure 5 is a working flow chart of a DC circuit breaker of the present method;

[0067] Step 301, Fault Preparation Process

[0068] Specifically, during normal system operation, the DC circuit breaker capacitor needs to be pre-charged. At this time, switches Ti and T are turned on to charge the capacitor using the DC system. After charging is completed, the switch is naturally turned off.

[0069] Step 302, steady-state operation process

[0070] Specifically, when the DC system operates normally, the DC circuit breaker operates in steady-state mode. At this time, the high-frequency mechanical switch UFD of the current branch is closed, the auxiliary converter module ASM is turned on, and the remaining switch devices are in the disconnected state. When the system operates in a steady state, the current passing through the line is small, and the number of IGBs required in series in the auxiliary converter module is small, achieving low-loss steady-state current flow of the circuit breaker.

[0071] Step 303: Fault Isolation Process

[0072] Specifically, after a short-circuit fault occurs in the DC system, the system protection device detects the fault and sends an instruction to the control system to control the operation of the DC circuit breaker. After receiving the action instruction, the thyristors T1 and T3 in the power electronic branch and the switch S in the negative voltage circuit are first controlled to be turned on, and the ASM is locked. The negative pressure generated by the closing forces the fault current to quickly transfer to the low-voltage position of the power electronic branch. When the current is reduced to the disconnection requirement of the high-frequency mechanical switch UFD, UFD is disconnected. At this time, the fault current completes the commutation process to the transfer branch. Then the coupling negative voltage branch switch S is turned off and T2 is triggered to be turned on. At this time, the pre-charged capacitor C begins to discharge, and a reverse voltage is applied to the thyristor T, prompting T to turn off, and the short-circuit current is forced to flow through the capacitor circuit: when the capacitor C is discharged, the short-circuit current continues to charge it in the reverse direction through the capacitor circuit, and the reverse voltage prompts the current to gradually transfer to the arrester energy consumption branch until the energy on the non-fault side is released.

[0073] Step 304, bypass energy release process

[0074] Specifically, the energy on the non-fault side is mainly absorbed and dissipated by the arrester, while the energy stored in the fault side inductor during the fault needs to form a loop with the earth through the reverse grounding thyristor Te in the current limiting circuit breaker, the secondary winding of the negative voltage circuit and the line fault point, and then discharge the energy through the earth.

[0075] Step 305: Capacitor residual energy dissipation process

[0076] Specifically, when the fault point is isolated, the residual energy of the capacitor after reverse charging is large, which needs to be dissipated before reclosing. It is only necessary to open the switch T during the discharge of the inductive energy on the fault side, and the residual energy of the capacitor will be dissipated by connecting to the ground through the loop CL-TT.

[0077] Embodiment 2:

[0078] This embodiment provides a specific process of transmitting the calculated non-fault side current clearing value to each DC circuit breaker and performing the current clearing operation through the control signal of the circuit breaker. This is a closed-loop operation based on the communication and control system. The following is a detailed explanation of the specific steps:

[0079] 1. Obtain the current clearing value on the non-fault side

[0080] Data acquisition: First, the current sensor monitors the current condition in the DC system in real time, especially the current on the non-fault side, and feeds the data back to the control system.

[0081] Distributed computing: The collected current data will be transmitted to remote computing nodes via satellite networks. On these nodes, the non-fault side current clearing value of each circuit breaker is calculated according to the formula Cl = Rsh × Ish / (1 + Rsh × Ish) through distributed computing methods (involving parallel computing on multiple servers).

[0082] 2. Transmit clear value

[0083] Communication network: The calculated removal value is transmitted to each DC circuit breaker via satellite network, optical fiber or other communication methods. The satellite network ensures fast and accurate data transmission even in remote or complex power grid environments.

[0084] Positioning information synchronization: The satellite network also synchronizes the geographic location of each circuit breaker and the corresponding current monitoring information to ensure that the signal can be accurately sent to the target circuit breaker to avoid confusion or misoperation.

[0085] 3. Control signal response of DC circuit breaker

[0086] Receiving control signals: After receiving the clear value sent from the control center or distributed computing node, each DC circuit breaker decodes and processes the signal through its internal control system.

[0087] Triggering power electronic components: The control system will trigger the relevant power electronic components in the circuit breaker, such as thyristors or IGBTs (insulated gate bipolar transistors), according to the received clearing value (i.e., CL). These components will begin to perform fault current clearing operations according to the instructions.

[0088] 4. Perform current clearing on the non-fault side

[0089] Adjust the circuit breaker status: The switches inside the circuit breaker (such as high-frequency mechanical switch UFD, auxiliary converter module ASM, etc.) will be adjusted according to the clearing value, and the appropriate branch or energy consumption module will be selected to consume the residual current on the non-fault side.

[0090] Energy discharge: In the bypass branch, the thyristor (such as the reverse grounding thyristor Te) will be triggered to open the bypass branch, and the energy will be discharged to the ground through the energy dissipation element (such as the arrester or resistor), thereby reducing the current on the non-fault side to an acceptable safety range.

[0091] Feedback monitoring: During the current clearing process, the current sensor continues to monitor the current value and feeds back to the control system to ensure that the current clearing is completed effectively.

[0092] 5. Feedback and closed-loop control after fault clearing

[0093] System status feedback: When the DC circuit breaker completes the current clearing on the non-fault side, the control system will feedback the results of the operation (such as whether the current has been cleared, the status of the circuit breaker, etc.) to the upper-level monitoring system through the communication network to ensure that the entire system recovers normally after the fault is cleared.

[0094] Closed-loop control: The system will further optimize operations based on the feedback data and perform repeated clearing or adjustments when necessary to ensure that the entire power grid can quickly and safely return to normal operation.

[0095] 6. Redundancy and fault tolerance mechanism

[0096] Multi-node redundant transmission: In order to ensure the reliability of data transmission, multiple nodes may be set up in the satellite network to synchronously transmit control signals, so that even if there is a communication problem at a certain node, the circuit breaker can receive instructions in time.

[0097] Fault-tolerant processing: If a sensor or control signal anomaly occurs during the current clearing process, the system can perform remedial operations through other monitoring devices (such as backup sensors) or recalculated clearing values ​​to ensure that the fault is completely cleared.

[0098] It can be understood that this process is a highly automated control and communication system. Through real-time monitoring, distributed computing, satellite network transmission and rapid response of DC circuit breakers, the system can quickly isolate and clear the current on the non-fault side after a fault occurs, ensuring the stability and safety of the entire power system.

[0099] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

[0100] Many other changes and modifications may be made without departing from the concept and scope of the present invention.It should be understood that the present invention is not limited to the specific embodiments, and the scope of the present invention is defined by the appended claims.

Claims

1. A DC circuit breaker, characterized in that: The DC circuit breaker comprises: a through-current branch, a transfer branch and a bypass branch; The current-carrying branch includes: a high-frequency mechanical switch UFD and an auxiliary commutation module ASM, which are used for low-loss current during normal operation to achieve bidirectional current; the transfer branch includes: a coupled negative voltage circuit and an energy-consuming branch, which are used to complete the transfer, suppression, removal and consumption of current during a fault; the bypass branch is composed of a reverse-grounded thyristor T, which is used to clear the dissipation of the inductive current on the fault side.

2. A DC circuit breaker according to claim 1, characterized in that: The DC circuit breaker adopts a capacitor multiplexing DC circuit breaker, and the working process of the DC circuit breaker includes: Failure preparation process: During normal system operation, the DC circuit breaker capacitor is pre-charged. At this time, switches Ti and T are turned on to charge the capacitor using the DC system. After charging is completed, the switch is naturally turned off. Steady-state operation process: When the DC system operates normally, the DC circuit breaker operates in steady-state mode. At this time, the high-frequency mechanical switch UFD of the current-carrying branch is closed, the auxiliary converter module ASM is turned on, and the switch devices of the rest are in the disconnected state. When the system operates in a steady state, the current passing through the line is small, and the IGB required in series in the auxiliary converter module ASM is very small, achieving low-loss steady-state current flow of the circuit breaker. Fault isolation process: When a short circuit fault occurs in the DC system, the system protection device detects the fault and sends an instruction to the control system to control the operation of the DC circuit breaker. After receiving the operation instruction, the thyristors T1 and T3 in the power electronic branch and the switch S in the negative voltage circuit are first controlled to be turned on, and the ASM is locked. The negative pressure generated by the closing forces the fault current to quickly transfer to the low-voltage position of the power electronic branch. When the current is reduced to the disconnection requirement of the high-frequency mechanical switch UFD, UFD is disconnected. At this time, the fault current completes the commutation process to the transfer branch; then the coupled negative voltage branch switch S is turned off and T2 is triggered to be turned on. At this time, the pre-charged capacitor C begins to discharge, and a reverse voltage is applied to the thyristor T, prompting T to turn off, and the short-circuit current is forced to flow through the capacitor circuit; when the capacitor C is discharged, the short-circuit current continues to charge it in the reverse direction through the capacitor circuit, and the reverse voltage prompts the current to gradually transfer to the arrester energy consumption branch until the energy on the non-fault side is released. Bypass energy release process: The energy on the non-fault side is absorbed and dissipated by the arrester, while the energy stored in the inductance on the fault side during the fault needs to form a loop with the earth through the reverse grounding thyristor Te in the current limiting circuit breaker, the secondary winding of the negative voltage circuit and the line fault point, and then discharge the energy through the earth; Capacitor residual energy dissipation process: When the fault point is isolated, the residual energy of the capacitor after reverse charging is large, which needs to be dissipated before reclosing. During the discharge of the inductive energy on the fault side, the switch T is opened, and the residual energy of the capacitor will be connected to the ground through the loop CL-TT for dissipation.

3. A mobile calculation circuit breaker non-fault side current clearing method, characterized in that: Applied to the DC circuit breaker according to any one of claims 1 to 2, the method comprises: Install satellite positioning equipment and current sensors in DC circuit breakers to locate and monitor each DC circuit breaker in real time, and send the control signal and current data of the DC circuit breaker to the satellite network; For each DC circuit breaker, the current on the non-fault side is measured using a current sensor and the measurement results are uploaded to the satellite network; On the satellite network, the non-fault side current of each DC circuit breaker is calculated by using a distributed computing method to obtain a clearing value of the non-fault side current; The clearing value of the non-fault side current is transmitted to each DC circuit breaker and cleared by a control signal of the DC circuit breaker.

4. A DC circuit breaker and a method for clearing current on the non-fault side of a mobile circuit breaker according to claim 3, characterized in that: The satellite network includes a plurality of satellite network nodes; the DC circuit breakers are arranged at intervals on the transmission network; and the DC circuit breaker signals interact with the satellite network nodes.

5. A DC circuit breaker and a method for clearing current on the non-fault side of a mobile circuit breaker according to claim 3, characterized in that: Determine the use environment and requirements of current sensors on transmission lines, including measurement range, accuracy and sensitivity, select the appropriate type of current sensor, install the current sensor on the transmission network, and finally perform data acquisition to record current data on the transmission lines; Analyze and preprocess the current data to be transmitted, determine the accuracy, sensitivity, response time performance indicators of the sensor data, and perform encryption processing; Select matching satellite network nodes and transmission networks, and transmit the processed current data to be transmitted to corresponding network nodes for mobile computing processing.

6. A DC circuit breaker and a method for clearing current on the non-fault side of a mobile circuit breaker according to claim 3, characterized in that: The method of calculating the non-fault side current of each DC circuit breaker by using a distributed computing method includes: Based on the measurement result of the current sensor on the non-fault side current, the short-circuit impedance Rsh and the short-circuit current Ish are calculated; then the clearing value of the non-fault side current is calculated; Single-phase fault: Cl = Rsh × Ish / (1 + Rsh × Ish) Wherein, Cl represents the clearing value of the current on the non-fault side, Rsh represents the short-circuit impedance, and Ish represents the short-circuit current; In the case of multi-phase faults, the formula for clearing the non-fault side current is corrected to take into account the phase impedance; the specific correction method is as follows: Where: Ralt is the phase-to-phase impedance, K is the correction coefficient, which is used to reflect the specific impact of the phase-to-phase impedance.

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