Reactance system and method of operating the same

Abstract

The present application relates to a reactance system and its operation method. During normal operation, the bidirectional switch component is controlled to be in the off state. At this time, the magnetic potential of the primary winding and the secondary winding of the transformer is balanced, and the secondary winding forms a series resonant circuit through the inductor component and the capacitor component. The equivalent impedance of the reactance system is extremely low, which does not affect the normal transmission of the cable current. In the case of a need for reactance adjustment, for a sub-cable with a smaller equivalent impedance, the control component outputs a PWM signal of a target duty cycle to the bidirectional switch component, so that the capacitor component is in a short-circuit state with a certain duty cycle during the positive half-cycle and the negative half-cycle of the power supply, and the equivalent impedance of the reactance system increases rapidly. By configuring different target duty cycles, dynamic adjustment of the equivalent impedance is achieved. In this way, when the impedance of the double-split cable is asymmetric, the reactance system can be used to increase the equivalent impedance of the sub-cable with a larger transmission current, so that the two sub-cables maintain impedance symmetry, thereby maintaining the transmission current balance.

Description

Technical Field

[0001] The present application relates to the field of cable technology, and in particular to a reactance system and an operating method thereof. Background Art

[0002] In modern power systems, cable transmission has the advantages of high reliability and is not easily affected by external environmental and climatic factors. It can also save land space and improve the neatness and beauty of the city. With the development of power grid technology, the transmission capacity of a single high-voltage cable can no longer meet the growing load demand. Therefore, it is necessary to use double-split (co-directional parallel) cables for power transmission to improve the cable's carrying capacity and transmission capacity.

[0003] However, when using double-split cables for power transmission, the impedance of the two sub-cables running in parallel will be asymmetric due to line differentiation caused by path length and manufacturing process differences, electromagnetic coupling between multiple cables, etc., which will cause unbalanced transmission current. Summary of the invention

[0004] Based on this, it is necessary to provide a reactance system and an operation method thereof to address the problem of impedance asymmetry of the two sub-cables in a double-split cable.

[0005] A reactance system comprises: a capacitor component, a transformer, an inductor component, a bidirectional switch component and a control component, wherein the primary winding of the transformer is connected in series to at least one sub-cable of a double-split cable; the first end of the inductor component is connected to the first end of the secondary winding of the transformer, the second end of the inductor component is connected to the first end of the capacitor component, and the second end of the capacitor component is connected to the second end of the secondary winding of the transformer; the first end of the bidirectional switch component is connected to the first end of the capacitor component, and the second end of the bidirectional switch component is connected to the second end of the capacitor component; the control component is connected to the control end of the bidirectional switch component; the control component is used to output a PWM signal of a target duty cycle to the bidirectional switch component when there is a need for reactance adjustment, so as to increase the equivalent impedance of the sub-cable that transmits a larger current.

[0006] In one embodiment, the bidirectional switch component includes a first diode, a second diode, a third diode, a fourth diode and a bidirectional controllable switch, the anode of the first diode and the cathode of the second diode are respectively connected to the first end of the capacitor component, the anode of the third diode and the cathode of the fourth diode are respectively connected to the second end of the capacitor component, the cathode of the first diode and the cathode of the third diode are respectively connected to the first end of the bidirectional controllable switch, the anode of the second diode and the anode of the fourth diode are respectively connected to the second end of the bidirectional controllable switch, and the control end of the bidirectional controllable switch is connected to the control component.

[0007] In one embodiment, the bidirectional switch component further includes a first resistor, a second resistor, a third resistor and a fourth resistor, the first resistor is connected in parallel with the first diode, the second resistor is connected in parallel with the second diode, the third resistor is connected in parallel with the third diode, and the fourth resistor is connected in parallel with the fourth diode.

[0008] In one embodiment, the bidirectional switch component further includes a protection inductor, the cathode of the first diode and the cathode of the third diode are respectively connected to the first end of the protection inductor, and the second end of the protection inductor is connected to the first end of the bidirectional controllable switch.

[0009] In one embodiment, the inductive system further includes a current detector and a voltage detector, the second end of the inductive component is connected to the first end of the capacitive component via the current detector, the voltage detector is arranged in the bidirectional switch component, and the current detector and the voltage detector are respectively connected to the control component.

[0010] In one embodiment, the control component includes a current PI controller, a voltage PI controller and a processor, the current detector is connected to the current PI controller, the voltage detector is connected to the voltage PI controller, the current PI controller and the voltage PI controller are respectively connected to the processor, and the processor is connected to the control end of the bidirectional switch component.

[0011] In one of the embodiments, the reactance system further includes at least one of a local monitoring terminal, a human-computer interaction device and a remote terminal, and the local monitoring terminal, the human-computer interaction device and the remote terminal are respectively connected to the control component.

[0012] In one embodiment, the reactance system further includes an overvoltage protection circuit, which is connected in parallel to both ends of the capacitor component and is connected to the control component.

[0013] The present application provides an operating method based on the above-mentioned reactance system, and the operating method includes: monitoring whether the reactance system has a reactance adjustment requirement; when there is a reactance adjustment requirement, determining a target duty cycle; outputting a PWM signal of the target duty cycle to the bidirectional switch component to control the bidirectional switch component to conduct and operate, so as to increase the equivalent impedance of the sub-cable that transmits a larger current.

[0014] In one of the embodiments, the monitoring of whether the reactance system has a reactance adjustment requirement includes: detecting whether the transmission current of the double-split cable is balanced; and determining that the reactance system has a reactance adjustment requirement when the transmission current is unbalanced.

[0015] The above-mentioned reactance system and its operation method, in normal operation, the control component controls the bidirectional switch component to be in the off state, at this time, the magnetic potential of the primary winding and the secondary winding of the transformer are balanced, the secondary winding forms a series resonant circuit through the inductor component and the capacitor component, and the equivalent impedance of the reactance system is extremely low, which does not affect the normal transmission of the cable current. In the case of a need for reactance adjustment, for a sub-cable with a smaller equivalent impedance, the control component outputs a PWM signal of a target duty cycle to the bidirectional switch component, so that the capacitor component is in a short-circuit state with a certain duty cycle during the positive half-cycle and the negative half-cycle of the power supply, and the equivalent impedance of the reactance system increases rapidly. By configuring different target duty cycles, dynamic adjustment of the equivalent impedance is achieved. In this way, when the impedance of the double-split cable is asymmetric, the reactance system can be used to increase the equivalent impedance of the sub-cable with a larger transmission current, so that the two sub-cables maintain impedance symmetry, thereby maintaining the transmission current balance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a schematic diagram of the structure of the reactance system in one embodiment of the present application;

[0018] Figure 2 This is a schematic diagram of the structure of the reactance system in another embodiment of the present application;

[0019] Figure 3 This is a schematic diagram of the structure of a reactance system in another embodiment of the present application;

[0020] Figure 4 This is a schematic diagram of the structure of a reactance system in yet another embodiment of the present application;

[0021] Figure 5 This is a schematic diagram of the structure of the reactance system in another embodiment of the present application;

[0022] Figure 6 Schematic diagram of the operation flow of the reactance system in one embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0024] See also Figure 1 The present application provides a reactance system, including: a capacitor component C, a transformer T, an inductor component L, a bidirectional switch component 10 and a control component 20, wherein the primary winding of the transformer T is connected in series to at least one sub-cable of a double-split cable; the first end of the inductor component L is connected to the first end of the secondary winding of the transformer T, the second end of the inductor component L is connected to the first end of the capacitor component C, and the second end of the capacitor component C is connected to the second end of the secondary winding of the transformer T; the first end of the bidirectional switch component 10 is connected to the first end of the capacitor component C, and the second end of the bidirectional switch component 10 is connected to the second end of the capacitor component C; the control component 20 is connected to the control end of the bidirectional switch component 10; the control component 20 is used to output a PWM (Pulse Width Modulation) signal of a target duty cycle to the bidirectional switch component 10 when there is a need for reactance adjustment, so as to increase the equivalent impedance of the sub-cable that transmits a larger current.

[0025] Specifically, the primary winding of the transformer T is connected in series with at least one sub-cable of the double-split cable, and energy transfer and current regulation are achieved through electromagnetic coupling, and it is responsible for extracting energy from the double-split cable; the secondary winding of the transformer T is connected in series with the inductor component L and the capacitor component C to form a series resonant circuit. When the double-split cable is operating normally, the bidirectional switch component 10 is in the off state, and the impedance of the reactance system is close to zero, ensuring the normal flow of the double-split cable. When there is a need for impedance adjustment, the control component 20 will output a PWM signal with a certain duty cycle to control the bidirectional switch component 10 to turn on, and the resonant frequency of the inductor component L and the capacitor component C is quickly adjusted, and the system quickly increases the impedance. Specifically, the impedance can be increased by increasing the duty cycle of PWM, and the impedance can also be reduced by reducing the duty cycle of PWM.

[0026] In actual scenarios, the control component 20 uses high-frequency pulse width modulation technology to adjust the frequency and duty cycle of the trigger pulse of the bidirectional switch component 10 to achieve the purpose of flexibly controlling the impedance of the inductive system. The duty cycle range in the control process is adjustable from 0% to 100% to meet the needs under different operating conditions.

[0027] In a double-split cable, the reactance system provided in the present application can be set in one of the sub-cables. When the equivalent impedance of the sub-cable is low and the transmission current is large, its equivalent impedance can be increased to reduce the transmission current of the sub-cable and achieve transmission current balance. In another embodiment, the two cables of the double-split cable can also be respectively provided with the reactance system provided in the present application. When the equivalent impedance of any sub-cable is low, its equivalent impedance can be increased by the reactance system to reduce the transmission current of the sub-cable, so that the equivalent impedance and transmission current of the two sub-cables are symmetrical.

[0028] Through the reactance system of this embodiment, continuous and accurate equivalent impedance adjustment can be achieved. Under normal operation of the double-split cable, the magnetic potential of the primary winding and the secondary winding of the transformer T is balanced, and the reactance system can maintain an extremely low impedance value, which hardly affects the normal operation of the cable, and the current can pass smoothly. When the cable has a large transmission current, the reactance system can quickly increase its impedance and effectively limit the size of the transmission current. The reactance system has the advantages of fast response speed and high control accuracy, and can adjust the reactance value within milliseconds to cope with the situation of unbalanced transmission current.

[0029] In addition, the reactor system also has the function of dynamic reactive power compensation. According to the real-time demand for reactive power of the power grid where the double-split cable is located, the reactor system can dynamically adjust its impedance characteristics, optimize the grid voltage level by compensating reactive power, reduce voltage fluctuations, and improve power quality. The introduction of this technology can not only effectively solve the problem of excessively high or low voltage, but also significantly improve the power factor of the power grid, reduce power loss in the system, and extend the service life of power equipment.

[0030] In this way, the controllable and adjustable reactance system based on the above-mentioned magnetic potential balance principle can not only effectively deal with the current limitation problem, but also realize dynamic reactive power compensation, greatly improving the power supply quality and system stability of the power grid. Through the application of this technology, the loss of the power system has been effectively reduced, the operating efficiency and economy have been significantly improved, and the reliability and safety of the power system have been further guaranteed. The promotion and application of this technology is of great significance to promoting the modernization of the power industry, improving the technical level of the power grid, and adapting to the development of the future power system.

[0031] It can be understood that the types of the inductor component L and the capacitor component C are not unique. The inductor component L can be a single inductor or a component structure in which multiple inductors are connected in series and / or in parallel; the capacitor can be a capacitor or a component structure in which multiple capacitors are connected in series and / or in parallel, without specific limitation.

[0032] It should be pointed out that the type of bidirectional switch component 10 is not unique. Any switching device can be used as long as it can be triggered to conduct in both the positive and negative half-cycles of the power supply when impedance adjustment is required, so that the capacitor component C is short-circuited, thereby achieving equivalent impedance adjustment.

[0033] For example, in one embodiment, see Figure 2The bidirectional switch component 10 includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4 and a bidirectional controllable switch Q, wherein the anode of the first diode D1 and the cathode of the second diode D2 are respectively connected to the first end of the capacitor component C, the anode of the third diode D3 and the cathode of the fourth diode D4 are respectively connected to the second end of the capacitor component C, the cathode of the first diode D1 and the cathode of the third diode D3 are respectively connected to the first end of the bidirectional controllable switch Q, the anode of the second diode D2 and the anode of the fourth diode D4 are respectively connected to the second end of the bidirectional controllable switch Q, and the control end of the bidirectional controllable switch Q is connected to the control component 20.

[0034] Specifically, the bidirectional switch component 10 of this embodiment includes a bidirectional controllable switch Q and four power diodes, so as to control the impedance state of the reactance system. By adjusting the conduction state of the bidirectional controllable switch Q, the circuit can quickly switch the impedance value, thereby limiting the transmission current or performing reactive power compensation. Through the configuration of the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4, in the first power supply half cycle (which can be a positive half cycle), the current flows through the first diode D1, the bidirectional switch component 10 and the fourth diode D4 in sequence, thereby short-circuiting the capacitor component C; and in the second power supply half cycle (which can be a negative half cycle), the current flows through the third diode D3, the bidirectional switch component 10 and the second diode D2 in sequence, thereby short-circuiting the capacitor component C.

[0035] It should be pointed out that the type of the bidirectional controllable switch Q is not unique, and can be IGBT (Insulate Gate Bipolar Transistor), IGCT (Integrated Gate Commutated Thyristor), etc., without specific limitation.

[0036] It can be understood that, in one embodiment, the control component 20 includes a driving circuit for driving the bidirectional controllable switch Q. In actual scenarios, in order to achieve a fast switching response, the driving circuit needs to be able to provide sufficient driving current while ensuring the accuracy of signal transmission. Taking IGBT as an example, a dedicated IGBT driving circuit can be used to optimize the signal transmission path, improve the switching efficiency of the IGBT, and ensure that it can work stably in a high-frequency environment.

[0037] See also Figure 3 In one embodiment, the bidirectional switch component 10 further includes a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, the first resistor R1 is connected in parallel with the first diode D1, the second resistor R2 is connected in parallel with the second diode D2, the third resistor R3 is connected in parallel with the third diode D3, and the fourth resistor R4 is connected in parallel with the fourth diode D4.

[0038] Specifically, in order to improve the operating safety of the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4, the solution of this embodiment further connects resistors in parallel at both ends of the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4.

[0039] It should be noted that the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 may be a single resistor, or a resistor component consisting of a plurality of resistors connected in series and / or in parallel, without specific limitation.

[0040] Please continue reading Figure 3 In one embodiment, the bidirectional switch component 10 further includes a protection inductor Lr, a cathode of the first diode D1 and a cathode of the third diode D3 are respectively connected to a first end of the protection inductor Lr, and a second end of the protection inductor Lr is connected to a first end of the bidirectional controllable switch Q.

[0041] Specifically, in order to protect the bidirectional controllable switch Q from voltage spikes and current shocks, a protective inductor Lr is also configured in the reactance system to serve as a buffer. During the operation of the bidirectional controllable switch Q, the surge current is limited to avoid damage to the power equipment caused by transient shocks caused by the switching operation, effectively extend the service life of the bidirectional controllable switch Q, ensure its reliable switching at high frequency, and further improve the stability of the system operation.

[0042] See also Figure 4 In one embodiment, the reactance system further includes a current detector 41 and a voltage detector 42, the second end of the inductor component L is connected to the first end of the capacitor component C through the current detector 41, the voltage detector 42 is arranged in the bidirectional switch component 10, and the current detector 41 and the voltage detector 42 are respectively connected to the control component 20.

[0043] Specifically, the current detector 41 can monitor the cable current in real time, and send the detected cable current to the control component 20, so that the control component 20 can judge abnormal conditions such as unbalanced transmission current. Similarly, the voltage detector 42 can monitor the cable voltage in real time, and send the detected cable voltage to the control component 20, so that the control component 20 can judge abnormal conditions such as overvoltage. In this way, the control component 20 can determine whether impedance adjustment is required in combination with the real-time cable operation status.

[0044] In another embodiment, the control component 20 has a data storage function. The control component 20 can store the cable current and cable voltage obtained by real-time monitoring, that is, it can store the operating data of the reactance system for a long time for historical data analysis and operation and maintenance decision-making. Furthermore, by introducing a big data analysis module, the control component 20 can analyze the long-term stored data, identify operating trends, predict potential faults, and provide an optimized operation strategy for the system. Big data analysis can also help evaluate the reactive power demand of the power grid and further optimize the operating parameter settings of the reactance system.

[0045] See also Figure 5 In one embodiment, the control component 20 includes a current PI controller 21, a voltage PI controller 22 and a processor 23, the current detector 41 is connected to the current PI controller 21, the voltage detector 42 is connected to the voltage PI controller 22, the current PI controller 21 and the voltage PI controller 22 are respectively connected to the processor 23, and the processor 23 is connected to the control end of the bidirectional switch component 10.

[0046] Specifically, the PI controller, also known as proportional integral control, adjusts its output signal according to the input error signal (i.e. the deviation between the set value and the actual value) to reduce the error. Specifically, the PI controller compares the collected data with a set value, and then uses the difference as feedback of the control result to calculate the new output value, so that the system data reaches or stabilizes near the set value.

[0047] Specifically, in the scheme of this embodiment, the current PI controller 21 monitors the cable current signal in real time, and generates an adjustment signal by comparing the actual current with the set target value. The current PI loop output directly adjusts the PWM signal of the bidirectional switch component 10 (that is, adjusts the duty cycle of the PWM signal) so that the current quickly reaches the target value and achieves a fast dynamic response. The voltage PI controller 22 is responsible for monitoring the cable voltage, and generates an average control signal according to the change in voltage to adjust the PWM duty cycle of the bidirectional switch component 10. The function of the voltage PI controller 22 is to adjust the overall impedance of the reactance system to meet the stability of the voltage demand, especially when the reactive power demand changes. The current detector 41 is used to collect the cable current signal in real time and feed back the actual current to the current PI controller 21 in the control component 20. By accurately monitoring the current fluctuation, the current PI controller 21 can respond quickly to ensure that the cable output current remains within the preset range, that is, to ensure the output current balance.

[0048] In summary, the real-time signal output by the current PI controller 21 is directly used to adjust the PWM duty cycle of the bidirectional switch assembly 10 to ensure accurate control of the current; the average signal output by the voltage PI controller 22 is used for long-term adjustment to control the global response of the reactance system and ensure the stability of the cable voltage. In this way, the two work together to ensure the dynamic response speed of the system, improve the stability of the voltage and current, and avoid instability caused by changes in cable working conditions (such as excessive output current or changes in reactive power demand).

[0049] The reactance system achieves real-time regulation through a closed-loop control mechanism. When the output current of the cable is too large or the reactive power demand of the power grid changes, the control component 20 can adjust the impedance of the reactance system in real time through the current PI controller 21 and the voltage PI controller 22. The current PI controller 21 is used to quickly respond to current fluctuations, and the voltage PI controller 22 adjusts voltage changes on a longer time scale, ultimately ensuring the safe and stable operation of the cable. The current detector 41 compares the actual cable current signal with the set value and feeds it back to the control component 20. By adjusting the PWM signal in real time, the control component 20 can dynamically control the equivalent impedance of the reactance system to ensure that the cable current remains within a safe range. This closed-loop control strategy significantly improves the response speed and regulation accuracy of the reactance system.

[0050] In one embodiment, see Figure 5 In order to improve the operational safety of the reactance system, a resistor may be connected in series with the primary winding of the transformer T, that is, after a resistor is connected in series with the primary winding of the transformer T, it is then connected in series with the sub-cable.

[0051] In one of the embodiments, the reactance system further includes at least one of a local monitoring terminal, a human-computer interaction device, and a remote terminal, and the local monitoring terminal, the human-computer interaction device, and the remote terminal are respectively connected to the control component 20.

[0052] Specifically, in order to improve the adaptive capability and automation level of the system, a local monitoring terminal may be introduced, which specifically includes an intelligent monitoring module and an adaptive adjustment module.

[0053] Intelligent monitoring module: This module integrates multiple sensors to comprehensively monitor the cable operation status. By analyzing the monitoring data, it can predict the trend of faults or cable current fluctuations in advance, thereby adjusting the working status of the reactance system in advance.

[0054] Adaptive adjustment module: With the support of the intelligent monitoring module, the system can automatically adjust the impedance of the reactance system according to real-time operating conditions, such as load fluctuations or the access of new energy sources. This adaptive adjustment mechanism can achieve intelligent adjustment of the system without relying on human intervention, ensuring that the power system operates in the best state.

[0055] In order to meet the needs of smart grids, remote monitoring and communication functions can be added. The reactance system includes a remote terminal. The control component 20 is equipped with a remote communication function. The control component 20 can communicate with the remote terminal (such as the power dispatching center) in real time, upload operating data and status information, and provide the remote terminal with real-time monitoring of the working status of the reactance system. The system also supports remote control operations. Operators can remotely adjust the operating parameters of the reactance system (such as impedance value, cooling system, etc.) through the remote terminal to achieve flexible control of the system. Especially in emergency situations, the remote control function can effectively reduce the reaction time and improve the system response speed. The system supports multiple communication protocols (such as IEC 61850, etc.) to ensure compatibility with existing power grid management systems, and supports data encryption and secure transmission to ensure the reliability and security of remote control.

[0056] In order to improve the convenience and visualization of operation, a human-machine interaction device can be added. The operator can use the human-machine interaction device to monitor the operating status of the reactance system in real time, including the visualization of key parameters such as current, voltage, and temperature. At the same time, the human-machine interaction device supports simple and easy-to-understand graphical operations to help operators make adjustments quickly. Furthermore, the human-machine interaction device also has an operation log function. The human-machine interaction device can record a detailed log of each operation, help analyze the operation history, and provide a backtracking function when a fault occurs.

[0057] In one embodiment, in order to improve the reliability and safety of the system, a fault warning and fast switching function may be added to the reactance system. The specific implementation includes:

[0058] Fault warning mechanism: When the intelligent monitoring module detects an abnormal signal, the system will issue a fault warning signal in advance. This warning mechanism can notify the operator through sound and light alarms or through the communication system, and take corresponding measures in time to avoid further expansion of the fault.

[0059] Fast switching mechanism: When a serious fault occurs in the power grid, the fast switching mechanism can automatically disconnect the reactance system to prevent the fault from spreading. This mechanism uses high-speed switching devices to quickly switch to backup lines or directly cut off the connection with the power grid when a serious fault (such as short circuit, serious voltage instability, etc.) is detected to ensure the safety of equipment and the power grid.

[0060] In one embodiment, in order to improve the self-healing ability of the system after a fault occurs, fault self-diagnosis and automatic repair functions can be added. The specific implementation method is as follows: the system has an embedded self-diagnosis function module. When an abnormal device is detected (such as abnormal heating of the reactance system, failure of the bidirectional switch component 10, etc.), the system can automatically perform internal diagnosis, determine the fault type and fault location, and form a detailed fault report to help quickly locate the problem. Based on the fault diagnosis, if the system determines that the fault is not serious (such as local overheating, minor component failure, etc.), the system can start the automatic repair function, for example, by adjusting the impedance value to balance the system, reduce the local load, achieve self-repair, and avoid system shutdown due to minor faults.

[0061] It should be noted that, in one embodiment, in order to improve the reliability of the system and prevent the failure of key components from causing system interruption, a redundant design and a backup mechanism can be introduced. The specific implementation method is as follows: a redundant design is introduced on the key components of the reactance system (such as the bidirectional switch component 10, the capacitor component C, the inductor component L, etc.), that is, a backup component is added on the basis of the original component. When the main component fails, the system can automatically switch to the backup component to ensure that the system operation is not interrupted. The system is designed with multiple operating modes. When the main mode fails, it can quickly switch to the backup mode. The backup mechanism includes a backup reactance system configuration, a backup control path, etc., to ensure that the system can still maintain basic functions at critical moments.

[0062] In one embodiment, in order to improve the long-term stability of the system and extend the service life of the components, a temperature management and cooling system can be added. The specific implementation method is as follows: Install temperature sensors at key components of the reactance system (such as the bidirectional switch component 10, the capacitor component C, the inductor component L, etc.) to monitor the temperature status of each part of the system in real time. Once the temperature is found to be too high, the system will trigger cooling measures to prevent overheating and damage to the components. In order to cope with high temperature conditions, an active cooling system is designed, including air cooling and liquid cooling. When the system detects that the temperature of the component exceeds the preset value, the active cooling system will start to quickly reduce the temperature of the equipment to avoid system failure due to excessive temperature.

[0063] In one embodiment, the reactance system further includes an overvoltage protection circuit, which is connected in parallel to both ends of the capacitor component C and is connected to the control component 20 .

[0064] Specifically, when the voltage of the power grid is too high, the control component 20 can control the overvoltage protection circuit to conduct and operate, absorb the excess energy in the power grid, and prevent the overvoltage from damaging the components. This overvoltage protection mechanism effectively ensures the stable operation of the system under the condition of power grid voltage fluctuations. The type of overvoltage protection circuit is not unique. In one embodiment, it includes a controllable switch and a varistor connected in series. The controllable switch can be turned on and operated according to the control signal of the control component 20 when there is a demand for overvoltage protection.

[0065] In one embodiment, the reactance system is also configured with an overcurrent protection circuit, and the system monitors the cable current in real time through the current detector 41 and compares it with the set value. If the current exceeds the preset value, the system immediately activates the overcurrent protection, increases the impedance of the reactance system, limits the current peak, and avoids equipment overload.

[0066] In one embodiment, in order to adapt to the complex power system environment, the inductor system can also be designed to resist interference. Specifically, an anti-electromagnetic interference function is added to the inductor system to ensure that the system can still operate stably in a complex electromagnetic environment and avoid misoperation or failure caused by electromagnetic interference.

[0067] In one embodiment, the inductive system can also be designed for environmental adaptability, specifically, the structure and materials of the inductive system are designed to adapt to a variety of harsh environments (such as high humidity, high dust, etc.), and protective measures are provided, such as improved waterproof and dustproof levels, to ensure long-term stable operation of the system in various extreme environments.

[0068] In one embodiment, an energy feedback module can also be introduced into the reactance system to feed back the excess energy generated by the system during operation (such as the excess electric energy stored in the capacitor component C) to the power grid, thereby reducing energy waste and improving the overall energy efficiency of the system. Through the intelligent energy management system, the energy feedback amount is adjusted in real time to avoid excessive energy feedback in the power grid and ensure optimal energy utilization.

[0069] The reactance system provided in the embodiment of the present application has the following advantages:

[0070] Fast dynamic response: Based on PWM-controlled bidirectional controllable switch technology, the system can respond quickly to grid faults in a short time, and achieve millisecond-level transmission current limitation and reactive power compensation by dynamically adjusting the impedance of the reactance system.

[0071] Continuously adjustable impedance: By adjusting the duty cycle of the PWM signal, the impedance of the reactance system can be continuously adjustable to adapt to the needs of the power grid under different working conditions and ensure the stability of the system.

[0072] Efficient reactive power compensation: By real-time monitoring of the grid operation status, the system can dynamically adjust the impedance according to the reactive power demand of the grid, improve the power factor and reduce power loss.

[0073] Multiple protection mechanisms: The designs of overvoltage protection, overcurrent protection and protection inductor Lr ensure the safe operation of the system under various complex power grid conditions.

[0074] In the above-mentioned reactance system, when the double-split cable is operating normally, the control component 20 controls the bidirectional switch component 10 to be in the off state. At this time, the magnetic potential of the primary winding and the secondary winding of the transformer T is balanced, and the secondary winding forms a series resonant circuit through the inductance component L and the capacitance component C. The equivalent impedance of the reactance system is extremely low and does not affect the normal transmission of the cable current. In the case of a need for reactance adjustment, for a sub-cable with a smaller equivalent impedance, the control component 20 outputs a PWM signal of a target duty cycle to the bidirectional switch component 10, so that the capacitor component C is in a short-circuit state with a certain duty cycle during the positive half-cycle and the negative half-cycle of the power supply, and the equivalent impedance of the reactance system increases rapidly. By configuring different target duty cycles, dynamic adjustment of the equivalent impedance is achieved. In this way, when the impedance of the double-split cable is asymmetric, the reactance system can be used to increase the equivalent impedance of the sub-cable with a larger transmission current, so that the two sub-cables maintain impedance symmetry, thereby maintaining the transmission current balance.

[0075] See also Figure 6 The present application provides an operating method based on the above-mentioned reactance system, including step 602, step 604 and step 606.

[0076] Step 602, monitoring whether the reactance system has a reactance adjustment requirement.

[0077] Step 604: determine a target duty cycle when reactance adjustment is required.

[0078] Step 606: output a PWM signal with a target duty cycle to the bidirectional switch component to control the bidirectional switch component to conduct and operate, so as to increase the equivalent impedance of the sub-cable that transmits a larger current.

[0079] Specifically, the structure of the reactance system is as shown in the above embodiment and the accompanying drawings. The reactance adjustment requirement is to control the bidirectional switch assembly 10 to conduct at different duty cycles to adjust the equivalent impedance of the reactance system. The reactance adjustment of the reactance system can be manually triggered by a user issuing a remote or local command, or the reactance system can be monitored according to the configured parameters and automatically triggered after the monitoring meets certain conditions, without specific limitation. Accordingly, it can be considered that there is a reactance adjustment requirement when an adjustment instruction is received or the set conditions are met.

[0080] The primary winding of the transformer T is connected in series with at least one sub-cable of the double-split cable, and energy transfer and current regulation are achieved through electromagnetic coupling, and it is responsible for extracting energy from the cable; the secondary winding of the transformer T is connected in series with the inductor component L and the capacitor component C to form a series resonant circuit. When the double-split cable is operating normally, the bidirectional switch component 10 is in the off state, and the impedance of the reactance system is close to zero, ensuring the normal flow of the double-split cable. When there is a need for impedance adjustment, the bidirectional switch component 10 is controlled to be turned on, and the system quickly increases the impedance through the dynamic adjustment of the transformer T. Specifically, the impedance can be increased by increasing the duty cycle of PWM, and the impedance can also be reduced by reducing the duty cycle of PWM. In this embodiment, the combination of the inductor component L and the capacitor component C forms a resonant circuit to adjust the resonant frequency of the system. When the system detects that there is a need for reactance adjustment, the resonant frequency of the inductor component L and the capacitor component C is quickly adjusted by turning on the bidirectional switch component 10, thereby increasing the impedance of the reactance system and limiting the transmission current.

[0081] In one of the embodiments, monitoring whether the reactance system has a reactance adjustment requirement includes: detecting whether the transmission current of the double-split cable is balanced; and determining that the reactance system has a reactance adjustment requirement when the transmission current is unbalanced;

[0082] Or, in one embodiment, monitoring whether the reactance system has a reactance regulation demand includes: detecting the load information of the power grid; and determining whether the reactance system has a reactance regulation demand when the load information indicates that the power grid is lightly loaded or heavily loaded.

[0083] Specifically, this embodiment uses the example of the reactance system monitoring the operating state of the power grid in which it is located, and triggering reactance adjustment after the monitoring meets certain conditions. The control component 20 can obtain the cable current in real time through the current detector 41 to determine whether the transmission current of the two sub-cables is balanced, that is, whether the transmission current of the two sub-cables is consistent; or by detecting the power grid load information, it is considered that there is a reactive power compensation demand when the power grid is lightly loaded or heavily loaded.

[0084] Normal operation state: When operating normally, the system adjusts the PWM signal (duty cycle is 0) through the control module to put the bidirectional switch component 10 in a non-conducting state, and the impedance of the reactance system is kept at a low level, so as not to interfere with the normal current flow of the double-split cable.

[0085] Unbalanced transmission current state: When the transmission current is unbalanced, the system detects the current change in real time through the current detector 41. Once the transmission currents of the two sub-cables are inconsistent, the control component 20 immediately adjusts the PWM duty cycle of the sub-cable with larger transmission current to turn on the bidirectional switch component 10. The impedance value of the reactance system increases rapidly, limiting the transmission current and finally achieving transmission current balance.

[0086] The system can not only quickly limit the transmission current when a fault occurs, but also has real-time reactive power compensation function. By dynamically adjusting the impedance value of the reactance system, the system can optimize the supply and consumption of reactive power according to the operation of the power grid, improve the power factor and reduce power loss.

[0087] Specifically, when the grid is lightly loaded, the system appropriately increases the impedance of the reactance system according to the detected voltage fluctuation to compensate for reactive power and stabilize the voltage. When the grid is heavily loaded and there is insufficient reactive power, the system reduces the impedance value of the reactance system to compensate for reactive power, prevent the voltage from dropping too fast, and ensure the normal operation of the power equipment.

[0088] The operation method of the above-mentioned reactance system is that when the double-split cable is operating normally, the control component 20 controls the bidirectional switch component 10 to be in the off state. At this time, the magnetic potential of the primary winding and the secondary winding of the transformer T is balanced, and the secondary winding forms a series resonant circuit through the inductance component L and the capacitance component C. The equivalent impedance of the reactance system is extremely low and does not affect the normal transmission of the cable current. In the case of a need for reactance adjustment, for a sub-cable with a smaller equivalent impedance, the control component 20 outputs a PWM signal of a target duty cycle to the bidirectional switch component 10, so that the capacitor component C is in a short-circuit state with a certain duty cycle during the positive half-cycle and the negative half-cycle of the power supply, and the equivalent impedance of the reactance system increases rapidly. By configuring different target duty cycles, dynamic adjustment of the equivalent impedance is achieved. In this way, when the impedance of the double-split cable is asymmetric, the reactance system can be used to increase the equivalent impedance of the sub-cable with a larger transmission current, so that the two sub-cables maintain impedance symmetry, thereby maintaining the transmission current balance.

[0089] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A reactance system, characterized in that: Applications for dual split cables include: Capacitor components; A transformer, wherein the primary winding of the transformer is connected in series to at least one sub-cable of the double-split cable; an inductor component, wherein a first end of the inductor component is connected to a first end of a secondary winding of the transformer, a second end of the inductor component is connected to a first end of the capacitor component, and a second end of the capacitor component is connected to a second end of the secondary winding of the transformer; a bidirectional switch component, wherein a first end of the bidirectional switch component is connected to a first end of the capacitor component, and a second end of the bidirectional switch component is connected to a second end of the capacitor component; A control component is connected to the control end of the bidirectional switch component; the control component is used to output a PWM signal with a target duty cycle to the bidirectional switch component when there is a need for reactance adjustment, so as to increase the equivalent impedance of the sub-cable that transmits a larger current.

2. The reactance system according to claim 1, characterized in that: The bidirectional switch component includes a first diode, a second diode, a third diode, a fourth diode and a bidirectional controllable switch, wherein the anode of the first diode and the cathode of the second diode are respectively connected to the first end of the capacitor component, the anode of the third diode and the cathode of the fourth diode are respectively connected to the second end of the capacitor component, the cathode of the first diode and the cathode of the third diode are respectively connected to the first end of the bidirectional controllable switch, the anode of the second diode and the anode of the fourth diode are respectively connected to the second end of the bidirectional controllable switch, and the control end of the bidirectional controllable switch is connected to the control component.

3. The reactance system according to claim 2, characterized in that: The bidirectional switch component also includes a first resistor, a second resistor, a third resistor and a fourth resistor, the first resistor is connected in parallel with the first diode, the second resistor is connected in parallel with the second diode, the third resistor is connected in parallel with the third diode, and the fourth resistor is connected in parallel with the fourth diode.

4. The reactance system according to claim 2 or 3, characterized in that: The bidirectional switch component further includes a protection inductor, a cathode of the first diode and a cathode of the third diode are respectively connected to a first end of the protection inductor, and a second end of the protection inductor is connected to a first end of the bidirectional controllable switch.

5. The reactance system according to claim 1, characterized in that: The inductive system also includes a current detector and a voltage detector. The second end of the inductive component is connected to the first end of the capacitive component through the current detector. The voltage detector is arranged in the bidirectional switch component. The current detector and the voltage detector are respectively connected to the control component.

6. The reactance system according to claim 5, characterized in that: The control component includes a current PI controller, a voltage PI controller and a processor, the current detector is connected to the current PI controller, the voltage detector is connected to the voltage PI controller, the current PI controller and the voltage PI controller are respectively connected to the processor, and the processor is connected to the control end of the bidirectional switch component.

7. The reactance system according to claim 1, characterized in that: The reactance system further includes at least one of a local monitoring terminal, a human-computer interaction device and a remote terminal, and the local monitoring terminal, the human-computer interaction device and the remote terminal are respectively connected to the control component.

8. The reactance system according to claim 1, characterized in that: The reactance system also includes an overvoltage protection circuit, which is connected in parallel to both ends of the capacitor component and is connected to the control component.

9. An operating method of the reactance system according to any one of claims 1 to 8, characterized in that: The operation method comprises: Monitor the reactance system to see if there is a need for reactance adjustment; Determine the target duty cycle when reactance regulation is required; A PWM signal with a target duty cycle is output to the bidirectional switch component to control the bidirectional switch component to conduct and operate, so as to increase the equivalent impedance of the sub-cable that transmits a larger current.

10. The operating method according to claim 9, characterized in that: The monitoring of whether the reactance system has a reactance adjustment requirement includes: Check whether the transmission current of the double-split cable is balanced; In the case where the delivered current is unbalanced, it is determined that the reactance system has a reactance adjustment requirement.

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