Apparatus and method for coordinating load break switch continuous current withstand and opening functions

Abstract

The present application relates to the technical field of performance inspection of load switch, and particularly relates to a device and method for coordinating continuous current resistance and breaking function of load switch, a linkage module of the device is used for connecting a moving contactor of a breaking branch circuit and a moving contactor of a main circuit, the breaking branch circuit and the main circuit bear corresponding currents when the load switch is in different states, a coordination module is used for determining a current value flowing through the linkage module according to current values borne by the breaking branch circuit and the main circuit at a current time, after the linkage module is structurally designed, real-time dynamic adjustment of the main circuit current and the breaking branch circuit current is realized, and the different states of the load switch include: normal current resistance state, short-circuit current resistance state, closing process and breaking process. Through phased current control and mechanical linkage optimization, the present application avoids unstable current switching in the load transfer process, such as tripping bounce, and improves the stability of the load switch.

Description

Technical Field

[0001] This invention relates to the field of performance testing technology for load switches, and specifically to a device and method for coordinating the continuous current withstand and interruption functions of a load switch. Background Technology

[0002] High-voltage load switches are key devices in power systems, functioning between high-voltage circuit breakers and high-voltage disconnectors. They are primarily used to control power transformers and distribute electrical energy. The structure of a high-voltage load switch includes a main circuit and a breaking branch, i.e., an arc-extinguishing device. These two components work together to achieve the function of safely switching current. The main circuit is the core conductive channel of the high-voltage load switch, responsible for carrying and transmitting normal load current and specified overload current. The breaking branch is the key arc-extinguishing system of the high-voltage load switch, used to quickly extinguish the arc during opening, preventing arc reignition that could cause equipment damage or personal injury. The coordinated operation of the main circuit and the breaking branch includes: Closing process: The main contacts close first, followed by the arc-extinguishing contacts, ensuring smooth current conduction. Opening process: The arc-extinguishing contacts open first, generating an arc, which is then quickly extinguished by the arc-extinguishing device. Finally, the main contacts completely open, forming a clear break.

[0003] Auxiliary circuits are the control, monitoring, protection, and signal transmission systems in high-voltage load switches, excluding the main circuit. For example, coordination circuits are switching devices where the main and auxiliary circuits work together. Coordination circuits must have the ability to withstand short-circuit currents and reliably interrupt circuits. Traditional coordination circuit designs have the following problems: Unstable load transfer: During the interruption process, current switching can easily cause tripping or arc reignition, leading to equipment damage.

[0004] Branch circuit overload risk: Improper current distribution between the main circuit and auxiliary circuit may lead to excessive current at a single point.

[0005] Complex insulation structure: To cope with extreme working conditions, redundant insulation measures need to be designed, which increases cost and volume.

[0006] Therefore, existing coordination circuits lack precise control over the dynamic current distribution between the main circuit and the switching branch, as well as a synergistic optimization scheme for mechanical linkage and dynamic / thermal stability. Summary of the Invention

[0007] Purpose of the invention: In order to overcome the shortcomings of the prior art, the present invention proposes a device for coordinating the continuous current withstand and interruption functions of a load switch, and the present invention also proposes a method for coordinating the continuous current withstand and interruption functions of a load switch.

[0008] Summary of the Invention: In a first aspect, the present invention provides a device for coordinating the continuous current withstand and interruption functions of a load switch, the device comprising: an interruption branch, a main circuit, a linkage module, and a coordination module; The linkage module is used to connect the moving contact of the disconnecting branch and the moving contact of the main circuit. When the load switch is in different states, the disconnecting branch and the main circuit bear the corresponding current. The coordination module is used to design the linkage module and determine the current value flowing through the linkage module based on the current value borne by the disconnecting branch and the main circuit at the current time. Finally, it realizes the real-time dynamic prediction of the main circuit current and the disconnecting branch current of the load switch in different states. The different states of the load switch include: normal withstand current condition, short circuit withstand current condition, closing process and opening process.

[0009] Furthermore, including: The current paths for the disconnected branch and the main circuit that bear the corresponding current are as follows: Breaking branch: The current flows from the current input main line of the load switch through the arc-extinguishing chamber to the stationary contact of the breaking branch moving contact, and finally flows out of the breaking branch moving contact. Main circuit: The current flows from the current input main line of the load switch through the stationary contact of the moving contact of the main circuit, and then flows out of the moving contact of the main circuit.

[0010] Furthermore, including: The coordination module includes: a stability analysis unit, a linkage module design unit, and a dynamic current distribution unit; The stability analysis unit is used to determine the current values ​​at the inlet of the disconnected branch and the main circuit, the current value at the moving contact of the main circuit, and the current value at the stationary contact of the moving contact of the disconnected branch based on the total input current and the current state of the load switch. Based on the above current values ​​and the simulation data or theoretical calculation data of computational fluid dynamics, the unit obtains the basic data of dynamic and thermal stability of the current at each position. The linkage module design unit is used to determine the starting positions of the main circuit moving contact and the branch circuit breaking moving contact, as well as the starting sequence of the main circuit moving contact and the branch circuit breaking moving contact, and to determine the mechanical structure parameters of the linkage module so that the linkage module can withstand the electrodynamic forces brought by the dynamic stability current, thermal stability current and short-circuit closing current. The dynamic current distribution unit is used to determine the real-time current of the linkage module based on the total input current, and then realize the dynamic prediction of the main circuit current and the branch current based on the different states of the load switch.

[0011] Furthermore, including: Determining the mechanical structure parameters for the linkage module includes: the linkage module uses a gear set or worm gear to realize the synchronous movement of the main circuit moving contact knife and the breaking branch moving contact knife, and by changing the gear ratio of the gear set or worm gear, the order of the main circuit moving contact knife and the breaking branch moving contact knife is changed, so that the main circuit moving contact knife and the breaking branch moving contact knife have a time interval when they move synchronously.

[0012] On the other hand, the present invention also provides a coordination method based on the continuous current withstand and breaking function of a load switch, which is implemented according to the aforementioned coordination module and specifically includes the following steps: Based on the total input current and the current state of the load switch, determine the current values ​​at the inlet of the disconnected branch and the main circuit, the current value at the moving contact of the main circuit, and the current value at the stationary contact of the moving contact of the disconnected branch. Based on the above current values ​​and the simulation data or theoretical calculation data of computational fluid dynamics, obtain the basic data of dynamic and thermal stability of the current at each position. Determine the starting positions of the main circuit moving contact and the branch circuit moving contact, as well as the starting sequence of the main circuit moving contact and the branch circuit moving contact, and determine the mechanical structure parameters for the linkage module so that the linkage module can withstand the electrodynamic forces brought about by the dynamic stability current, thermal stability current, and short-circuit closing current. The admittance of the corresponding line of the linkage module is determined based on the total input current, and the main circuit current and the breaking branch current are guided based on the different states of the load switch and different total input currents.

[0013] Furthermore, including: The determination of the admittance of the corresponding line of the linkage module based on the total input current, and the guidance of the main circuit current and the breaking branch current under different states of the load switch and different total input currents, includes: The current path formed by the main current input line, the interruption branch, the main circuit, and the linkage module is equivalent to a network diagram with four nodes. The line between the first and second nodes is the branch corresponding to the main current input line, the line between the second and third nodes is the interruption branch, the line between the second and fourth nodes is the main circuit, and the line between the third and fourth nodes is the linkage module. The admittances corresponding to the above four lines are denoted as y1, y2, y3, and y4, respectively, and the real-time currents are denoted as I1, I2, I3, and I4, respectively. Based on the connection relationship between nodes, the final node admittance matrix is ​​determined, and the relationship between the node voltage and the branch current is obtained based on the node voltage equation. By using the current conservation and voltage relationship of the second node, the static correlation between the admittance y4 of the linkage module and other admittances is obtained; Since I1 is different for different states, the first dynamic correlation relationship is formed between admittance y4 and other admittances under different states; Based on the adjustment relationship of the linkage module over time, a time function is introduced on the basis of the first dynamic correlation relationship to represent the second dynamic correlation relationship between the admittance y4 corresponding to the linkage module and other admittances.

[0014] Furthermore, including: The method of determining the admittance of the corresponding line of the linkage module based on the total input current, and guiding the main circuit current and breaking branch current under different states of the load switch and different total input currents, also includes: The current value of the load switch under four conditions is determined: normal withstand current condition, short circuit withstand current condition, closing process and opening process. That is, the input current value I1 at the first node. Therefore, under different conditions, the admittance y1 corresponds to different values, while the values ​​of admittance y2 and y3 remain unchanged, which are the overall admittances of the corresponding opening branch and the main circuit, respectively. Based on the current sharing relationship between the branch circuit and the main circuit when the load switch is in different states, assign corresponding current values ​​to I2 and I3; Based on the determined I1, I2, I3 and the second dynamic correlation, the values ​​of admittance y4 under different states are obtained; Based on the current admittance y4 value, guide the main circuit current and the breaking branch current under different load switch states and different total input currents.

[0015] Furthermore, including: The current sharing relationship between the branch circuit and the main circuit based on the load switch in different states includes: Under normal withstand current and short-circuit withstand current conditions, the current borne by the disconnecting branch is less than that borne by the main circuit; during the closing process, the disconnecting branch does not bear current, and the main circuit bears all current. After a few seconds after the closing process ends, it switches to the normal withstand current condition; during the opening process, the disconnecting branch bears all current, and the main circuit does not bear current.

[0016] Furthermore, including: The process of obtaining the admittance y4 values ​​under different states based on the determined I1, I2, I3 combined with the second dynamic correlation includes: Under normal withstand current conditions, short-circuit withstand current conditions, and during the breaking process, the current borne by the breaking branch and the main circuit under the action of the connecting module is determined based on the total current flowing into the total input. Different current values ​​at the linkage module are obtained based on the recommended values ​​under different states. The current values ​​are then substituted into the second dynamic correlation relationship to obtain the corresponding admittance y4. The admittance y4 under the three states is a fixed value and does not change with time. During the closing process: the current borne by the branch circuit and the main circuit under the action of the connecting module is determined according to the total current flowing into the total input; the current value at the linkage module is obtained according to the recommended value under the current state. There are two scenarios at this point: First, before closing begins, the current value is input into the second dynamic correlation to determine the admittance y4 before closing begins; second, after closing is complete... Then, since the short-circuit withstand current and the closing current are the same, the admittance y4 after closing is obtained. The admittance y4 after closing is input into the second dynamic correlation to obtain the corresponding parameters of the time function, thereby determining the relationship between the admittance y4 and time in this state.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following advantages: (1) This invention optimizes the current control and mechanical linkage of different circuits. Specifically, the use of linkage module and coordination module avoids unstable current switching during load transfer, such as tripping and bounce, and improves the stability of load switch in response to different situations.

[0018] (2) The coordination module of this invention first performs network diagram equivalents on the load switch based on the current path characteristics of the interrupted branch and the main circuit, and constructs the corresponding node admittance matrix. Then, based on the relationship between nodes and admittances, it determines the static and dynamic correlation between the admittance of the linkage module and the admittance of other nodes. Finally, based on the four cases of the load switch, it dynamically adjusts the current during the interruption / closing process, thereby protecting the equipment and having a positive effect on the overall temperature rise improvement and dynamic / thermal stability design. This dynamic adjustment is not only reflected in the adjustment of the linkage module current based on different cases of the load switch, but also improves the current adjustment value of the subsequent closing state by determining the parameter value of the time function based on the closing time.

[0019] (3) The device structure corresponding to the present invention is simple. While meeting the characteristics of high-voltage load switch, it reduces redundant insulation design and lowers system complexity and cost. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the load switch structure after adding the linkage module according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure and dynamic current distribution of the main circuit and the disconnected branch as described in an embodiment of the present invention; Figure 3 This is the equivalent network diagram of the load switch described in the embodiment of the present invention; Figure 4 This is a schematic diagram of the device structure for coordinating the continuous current withstand and interruption functions of a load switch according to an embodiment of the present invention; Figure 5 This is a flowchart of the method for coordinating the continuous current withstand and breaking functions of a load switch according to an embodiment of the present invention; Figure 6 This is a flowchart illustrating the method for dynamic current adjustment of a load switch under different conditions according to an embodiment of the present invention. Figure 7This is a schematic diagram of the structure of the coordination module described in an embodiment of the present invention; The diagram includes: 1. Connecting module; 2. Arc extinguishing chamber; 3. Stationary contact of the branch circuit moving contact; 4. Stationary contact of the main circuit moving contact; 5. Main circuit moving contact. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figure 4 As shown, the present invention provides a device for coordinating the continuous current withstand and interruption functions of a load switch. The device includes: an interruption branch, a main circuit, a linkage module, and a coordination module. In this embodiment, as Figure 1 The load switch includes a main current input line, with the total current flowing into the breaking branch and the main circuit. The breaking branch includes an arc-extinguishing chamber 2, which is connected to the stationary contact 3 of the moving contact of the breaking branch. The stationary contact 3 of the moving contact of the breaking branch is connected to or disconnected from the moving contact 4 of the breaking branch. The main circuit includes a stationary contact 5 and a moving contact 6 of the main circuit. The stationary contact 5 and the moving contact 6 of the main circuit are connected to or disconnected. A linkage module is connected between the moving contact of the breaking branch and the moving contact of the main circuit. That is, the main circuit and the breaking branch are connected through the linkage module 1. When the load switch is in different states, the breaking branch and the main circuit bear the corresponding current. The different states of the load switch include: normal withstand current condition, short-circuit withstand current condition, closing process, and opening process.

[0023] The coordination module determines the current value flowing through the linkage module based on the current value carried by the disconnected branch and the main circuit at the current time. After structural design of the linkage module, the real-time dynamic adjustment of the main circuit current and the disconnected branch current is realized.

[0024] like Figure 2 As shown, when the load switch is in different states, the disconnecting branch and the main circuit will carry different currents. The corresponding current paths for the disconnecting branch and the main circuit are as follows: In the breaking branch: the current flows from the load switch current I1 input to the main line, through the arc-extinguishing chamber, to the stationary contact of the breaking branch moving contact, the current value at the stationary contact of the breaking branch moving contact is I2, and finally flows out of the breaking branch moving contact. Main circuit: The current flows from the current input main line of the load switch through the stationary contact of the moving contact knife in the main circuit, and then flows out of the moving contact knife in the main circuit. The current value at the moving contact knife in the main circuit is I3, and then the current flowing through the connecting module is I4.

[0025] like Figure 7 As shown, the coordination module in this embodiment includes: a stability analysis unit, a linkage module design unit, and a dynamic current distribution unit.

[0026] In this embodiment, the stability analysis unit is used to determine the current value at the inlet of the disconnected branch and the main circuit, the current value at the moving contact of the main circuit, and the current value at the stationary contact of the moving contact of the disconnected branch based on the total input current and the current state of the load switch. Based on the above current values ​​and the simulation data or theoretical calculation data of computational fluid dynamics (CFD), the unit obtains the basic data of dynamic and thermal stability of the current at each location.

[0027] In a preferred embodiment, thermal stability focuses on assessing the device's thermal resistance under short-circuit current. CFD, on the other hand, verifies the rationality of theoretically calculated heat dissipation boundary conditions by simulating temperature field distribution, such as optimizing radiator design through airflow field analysis to reduce hot spot temperature. Dynamic stability focuses on the device's resistance to mechanical stress generated by short-circuit current. CFD can simulate conductor vibration frequency, stress distribution, and stress on support components to avoid resonant amplification of stress and ensure that mechanical strength meets requirements.

[0028] CFD simulation of conductor temperature gradient under different currents identifies hot spots and verifies the accuracy of theoretically calculated heat dissipation coefficients. CFD simulation of conductor vibration modes calculates dynamic stress distribution, and finite element analysis (FEA) verifies the mechanical strength of the support structure to prevent conductor deformation or breakage during short circuits. Therefore, based on the basic parameters of the linkage module provided by CFD, such as short-circuit current value, material heat capacity, and mechanical strength limit, the system can be optimized.

[0029] In this embodiment, the linkage module design unit is used to determine the starting position of the main circuit moving contact and the branch circuit moving contact, as well as the starting sequence of the main circuit moving contact and the branch circuit moving contact, and to determine the mechanical structure parameters for the linkage module so that the linkage module can withstand the electrodynamic forces brought by the dynamic stability current, thermal stability current and short-circuit closing current. In this embodiment, when the circuit is closed, the moving contact and stationary contact of the main circuit are fully engaged. When the branch circuit is closed, it forms a parallel path with the moving contact of the main circuit. When the circuit is opened, it disconnects the branch current to avoid overload of the main circuit. The specific function of the connecting module is as a synchronization device, which enables the moving contact of the main circuit and the moving contact of the branch circuit to move synchronously—performing opening and closing operations simultaneously. At the same time, it can also create a time interval between the moving contact of the main circuit and the moving contact of the branch circuit during synchronous movement, for example, the moving contact of the main circuit moves a few milliseconds before the moving contact of the branch circuit.

[0030] In this embodiment, the linkage module uses a gear set or worm gear to realize the synchronous movement of the main circuit moving contact knife and the breaking branch moving contact knife. By changing the gear ratio of the gear set or worm gear, the order of the main circuit moving contact knife and the breaking branch moving contact knife can be changed, so that a time interval is generated when the main circuit moving contact knife and the breaking branch moving contact knife move synchronously.

[0031] This embodiment can also have a variety of optional ways to change the current flow, such as using a rheostat or a series IGBT (insulated gate bipolar transistor) to realize the function of dynamically adjusting the current flowing through the breaking branch and the main circuit during the opening and closing process. If a sliding rheostat is used, the resistance value of the sliding rheostat will be dynamically changed through mechanical linkage. If a series IGBT group is used, the microcomputer unit will control the IGBT group to change the resistance value of the mechanical linkage and auxiliary current-carrying device, thereby changing the current of the switching branch and the main circuit.

[0032] The dynamic current distribution unit is used to determine the real-time current of the linkage module based on the total input current, thereby realizing the dynamic adjustment of the main circuit current and the interrupted branch current.

[0033] On the other hand, such as Figure 5 As shown, the present invention also provides a coordination method based on the continuous current withstand and breaking functions of a load switch, specifically including the following steps: S1 determines the current values ​​at the incoming line of the disconnected branch and the main circuit, the current value at the moving contact of the main circuit, and the current value at the stationary contact of the moving contact of the disconnected branch based on the total input current and the current status of the current switch. Based on the above current values ​​and the simulation data or theoretical calculation data of computational fluid dynamics, S1 obtains the basic data of dynamic and thermal stability of the current at each position.

[0034] S2 determines the starting positions of the main circuit moving contact and the branch circuit breaking moving contact, as well as the starting sequence of the main circuit moving contact and the branch circuit breaking moving contact, and determines the mechanical structure parameters for the linkage module so that the linkage module can withstand the electrodynamic forces brought by the dynamic stability current, thermal stability current and short-circuit closing current. S3 determines the admittance of the corresponding line of the linkage module based on the total input current, and guides the main circuit current and the breaking branch current under different states of the load switch and different total input currents.

[0035] In this embodiment, step S3 specifically includes: S31 equates the current path formed by the main current input line, the interruption branch, the main circuit, and the linkage module into a network diagram with four nodes. The line between the first and second nodes is the branch corresponding to the main current input line, the line between the second and third nodes is the interruption branch, the line between the second and fourth nodes is the main circuit, and the line between the third and fourth nodes is the linkage module. The admittances corresponding to the above four lines are denoted as y1, y2, y3, and y4, respectively, and the real-time currents are denoted as I1, I2, I3, and I4, respectively.

[0036] S32 determines the final node admittance matrix based on the connection relationship between nodes, and obtains the relationship between the node voltage and the branch current based on the node voltage equation.

[0037] In a preferred embodiment, such as Figure 3 As shown, based on Figure 2 The current path diagram of the load switch can be equivalent to an admittance network diagram. Since admittance is a physical quantity that describes the response of a circuit to current and voltage, it represents the ability of a linear circuit to respond to changes in current. Therefore, the current path network diagram can be represented by an admittance network diagram.

[0038] In this circuit, there are four nodes, and the admittances y1, y2, y3, and y4 correspond to different branches. The admittance at the input point from the first node to the second node is y1, and the corresponding current is I1. The admittance at the open branch from the second node to the third node is y2, and the corresponding current is I2. The admittance of the main circuit from the second node to the fourth node is y3, and the corresponding current is I3. The admittance of the mechanical linkage device from the third node to the fourth node is y4, and the corresponding current is I4.

[0039] And since the first node is only connected to the second node, its admittance is y1, therefore: Y11 = y1; ; The second node is connected to the first, third, and fourth nodes, and its admittances are y1, y2, and y3, respectively. Therefore:

[0040] The third node is connected to the second and fourth nodes, and their admittances are y2 and y4 respectively. Therefore:

[0041] The fourth node is connected to the second and third nodes, and its admittances are y3 and y4 respectively. Therefore: .

[0042] Therefore, the final nodal admittance matrix is: ; Therefore, according to ,get: ; S33 obtains the static correlation between the admittance y4 of the linkage module and other admittances through the current conservation and voltage relationship of the second node.

[0043] In this embodiment, the connecting module serves to assist in current flow and dynamically adjust the current between the switching branch and the main circuit. Based on the admittance y1 and time at the inputs of the first and second nodes, the admittance y4 of the mechanical linkage device is dynamically adjusted. Through the current conservation and voltage relationship of the second node, 3, and 4, we can obtain: ;in, , ; Therefore, after simplification, the static relationship between admittance y4 and y1 is as follows: .

[0044] S34 forms the first dynamic correlation between admittance y4 and other admittances under different states because I1 is different in different states.

[0045] In this embodiment, a dynamic correlation is introduced regarding I1, admittance y1, and y4: The admittance y1 is used to characterize four cases: normal withstand current, short-circuit withstand current, closing process, and opening process. That is, y1 corresponds to different values ​​in each of these four cases, denoted as y1(case(i)), where i = 0, 1, 2, 3; case(i) represents the different y1(case(i)) values ​​corresponding to the four cases: normal withstand current, short-circuit withstand current, closing process, and opening process. 1. The normal withstand current is y1(case(0)), at which time y1(case(0)) is the constant value of the current from the first node to the second node when I1 = the normal withstand current; 2. When the short-circuit withstand current is y1(case(1)), y1(case(1)) is the constant value when the current from the first node to the second node is I1 = the short-circuit withstand current. 3. During the closing process, it is y1(case(2)). At this time, y1(case(2)) is the constant value when the current from the first node to the second node is I1 = the closing current. y1(case(2)) is the same as y1(case(1)). During the interruption process, it is y1(case(3)), at which time y1(case(3)) is the constant value of the current from the first node to the second node when I1 = the short-circuit withstand current; In the above formula, y1V 12 This refers to the current I1 from the first node to the second node. Since the admittance y1 is currently expressed in the form y1(case(i)), I1 is now updated to the form I1(case(i)), where i = 0, 1, 2, 3; specifically: 1. The normal withstand current is I1(case(0)), which is a constant value under normal withstand current. 2. The short-circuit withstand current is I1(case(1)), and at this time I1(case(1)) is a constant value when the short-circuit withstand current is ; 3. During the closing process, I1(case(2)) is the constant value of the closing current. I1(case(2)) is the same as I1(case(1)). 4. During the interruption process, I1(case(3)) is the constant value when the short-circuit withstand current is reached; Therefore, the static association relationship is simplified and updated as follows: First dynamic relationship: .

[0046] Based on the adjustment relationship of the linkage module over time, S35 introduces a time function on the basis of the first dynamic correlation relationship and expresses the second dynamic correlation relationship between the admittance y4 corresponding to the linkage module and other admittances, thereby realizing the dynamic adjustment of the main circuit current and the interrupted branch current.

[0047] In this embodiment, the admittance y4 changes over time during the closing process due to the dynamic adjustment of the mechanical interlocking device. After closing, the load switch state is as follows: The circuit switches to short-circuit withstand mode within seconds, as shown in the table in Example 1 below. The closing current and short-circuit withstand current are the same value, requiring the introduction of a time function. h ( t ), represented as: ; where τ is a time constant, which is used to control the decay rate.

[0048] Therefore, the second dynamic association is represented as: Therefore, the nodal admittance matrix is ​​updated as follows: ; Depend on We can obtain: ; Specifically, based on the aforementioned second dynamic correlation, dynamic adjustment of the main circuit current and the interrupted branch current is achieved. In this embodiment, for example... Figure 6 As shown, the specific steps include: Step 1: Determine the current value of the load switch under four conditions: normal withstand current, short-circuit withstand current, closing process, and opening process. That is, the input current value I1 at the first node. Therefore, y1 corresponds to different values ​​under different conditions, while the values ​​of y2 and y3 remain unchanged. They are the overall admittances of the corresponding opening branch and main circuit, respectively. Step 2: Based on the current sharing relationship between the branch circuit and the main circuit when the load switch is in different states, assign corresponding current values ​​to I2 and I3; Step 3: Based on the determined I1, I2, I3 and the second dynamic correlation, obtain the values ​​of admittance y4 under different states; guide the main circuit current and the breaking branch current under different states of the load switch and different total input currents according to the current admittance y4 value.

[0049] In a preferred embodiment of this invention, step 3 specifically includes: Step 31: Input the voltage values ​​between the branches of the linkage module into the first dynamic correlation to obtain the theoretical value of admittance y4; Step 32: The theoretical value of the admittance y4 is combined with the current bearing relationship between the disconnected branch and the main circuit under different states to determine the number of adjustments to the linkage module, and the corresponding parameters of the time function in the second dynamic correlation are calculated to determine the adjusted admittance y4 under different states.

[0050] In this embodiment, under normal withstand current and short-circuit withstand current conditions, the current borne by the disconnecting branch is less than that borne by the main circuit; during the closing process, the disconnecting branch does not bear current, and the main circuit bears all current. After a few seconds after the closing process ends, it switches to the normal withstand current condition; during the opening process, the disconnecting branch bears all current, and the main circuit does not bear current.

[0051] Step 33: Based on the adjusted admittance y4 value, predict the subsequent action logic of the linkage module of the load switch under different states, including the current value passing through the linkage module.

[0052] Based on the above steps, a preferred embodiment of this invention includes: First, determine the rated closing and breaking current, normal withstand current, and short-circuit withstand current (four cases: normal withstand current, short-circuit withstand current, closing process, and opening process) of the load switch, i.e., the input current value I1 at the first node.

[0053] Second: y1 is used to characterize four situations: normal withstand current, short-circuit withstand current, closing process, and opening process. That is, y1 corresponds to different values ​​in the four situations, denoted as I1(case( iThe values ​​of y2 and y3 are fixed and are the overall admittance of the corresponding open branch and main circuit.

[0054] Three: Under four conditions—normal withstand current, short-circuit withstand current, closing process, and opening process—determine the appropriate current values ​​for the opening branch I2 and the main circuit I3 based on the following principles and the overall admittance of the corresponding opening branch and main circuit: Under normal current withstand conditions: the disconnected branch carries a small amount of current; the main circuit carries a large amount of current.

[0055] Under short-circuit withstand current conditions: the disconnected branch carries a small amount of current; the main circuit carries a large amount of current.

[0056] During the closing process: no current flows in the open branch; the main circuit carries the entire current. After the closing process is complete, ∆ t After a few seconds, it switches to normal withstand current condition, that is, the disconnected branch carries a small amount of current, while the main circuit carries a large amount of current.

[0057] During the interruption process: the interrupted branch carries all the current; the main circuit does not carry any current.

[0058] Fourth: After obtaining the currents I1, I2, and I3 under four conditions—normal withstand current, short-circuit withstand current, closing process, and opening process—substitute them into the formula. ; We obtain the theoretical y4 values ​​for the four cases. Substitute into the formula again: ; In order to obtain The corresponding time constant τ is used as a guide to dynamically adjust the main circuit current and the branch current that is interrupted.

[0059] The following are four scenarios. h ( t The calculation basis is as follows: 1. Under normal withstand current conditions: the disconnected branch carries a small current; the main circuit carries a large current. The mechanical linkage device and the auxiliary current-carrying device only need to adjust the admittance value at y4 once before the normal withstand current begins. h ( t )= h ( 0 The constant value is 1; 2. Under short-circuit withstand current conditions: the disconnected branch carries a small current; the main circuit carries a large current. The mechanical linkage device and auxiliary current-carrying device only need to adjust the admittance value at y4 once before the short-circuit withstand current begins. h ( t )= h (0 The constant value is 1; 3. During the closing process: the disconnected branch does not carry current; the main circuit carries all current. After the closing process is completed, after ∆t seconds, it switches to normal withstand current conditions, i.e., the disconnected branch carries a small amount of current; the main circuit carries a large amount of current. The mechanical linkage device and auxiliary current-carrying device need to adjust the admittance value at y4 once before the closing process, and then adjust the ∆t value after closing. t After a few seconds (when it becomes short-circuit resistant), the admittance value at y4 needs to be adjusted again. h ( t If the value is not a constant 1, the expression is: The second dynamic correlation relationship is obtained by substituting the calculated τ values ​​corresponding to the closed state and short-circuit withstand state. Therefore, based on different times h ( t The corresponding time constant τ is used to guide the action logic of the mechanical linkage device and the auxiliary current-passing device, so as to realize the dynamic adjustment of the main circuit current and the branch current of the disconnection. 4. During the interruption process: the interrupting branch carries the entire current; the main circuit does not carry current. The mechanical linkage device and the auxiliary current-carrying device only need to adjust the admittance value at y4 once before the interruption begins. h ( t )= h ( 0 The constant value is 1.

[0060] To verify the validity of this application, the following embodiments are provided: Firstly, this case directly uses recommended current values ​​to demonstrate that the current of the connecting module conforms to the four states of the load switch. Taking a closing current of 25kA, a normal withstand current of 630A, and a short-circuit withstand current of 25kA as an example, a recommended distribution table of I1-I4 is as follows:

[0061] The specific explanation is as follows: Under normal current withstand conditions: the total current flowing into the main input is I1=630A. Under the action of the connecting module, the disconnected branch carries a small amount of current, i.e., I3=30A; the main circuit carries a large amount of current, i.e., I2=600A; at this time, the current at the connecting module is I4=29A.

[0062] Under short-circuit withstand current conditions: the total current flowing into the main input is I1=25kA. Under the action of the connecting module, the disconnected branch carries a small amount of current, i.e., I3=1.2kA; the main circuit carries a large amount of current, i.e., I2=23.8kA; at this time, the current flowing through the connecting module is I4=1.16A.

[0063] During the closing process: The total current flowing into the main input is I1=25kA. Under the action of the connecting module, no current flows through the disconnected branch, i.e., I3=0A; the main circuit carries all the current, i.e., I2=25kA; at this time, the connecting module is in a closed state, with almost no current flowing through it, i.e., I4=0.1A.

[0064] During the switching process: The total current flowing into the main input is I1=630A. Under the action of the connecting module, the switching branch bears all the current, i.e., I3=630A; the main circuit does not bear the current, i.e., I2=0A; At this time, the current flowing through the connecting module is I4=630A.

[0065] Based on this, this embodiment also provides a case to prove the application. Taking a ring main unit as an example, the closing current is 20kA, the normal withstand current is 630A, the short-circuit withstand current is 20kA, the Δt value for switching from the closing process to the short-circuit withstand process is 30ms, the admittance value at y2 is 0.02 S (Siemens, admittance unit), and the admittance value at y3 is 0.05 S. A recommended distribution table of I1-I4 is as follows:

[0066] Based on the recommended I4 values ​​corresponding to the four switching states in the table, and the current value I1 of the branch corresponding to the current input main line between the first node and the second node, calculate the admittance values ​​y1 and y4 for the four switching states respectively. The admittance values ​​at y2 and y3 are fixed values ​​and do not change with the switching state.

[0067] 1. Under normal current withstand conditions: The total current flowing into the main input is I1=630A. Under the action of the connecting module, the disconnected branch carries a small amount of current, i.e., I3=30A; the main circuit carries a large amount of current, i.e., I2=600A; at this time, the current at the connecting module is I4=28A.

[0068] Substituting into the formula, we get .

[0069] Right now It is a constant value.

[0070] 2. Similarly, under the short-circuit withstand current condition...

[0071] Right now It is a constant value.

[0072] 3. During the closing process: The total current flowing into the main input is I1=25kA. Under the action of the connecting module, the branch circuit is cut off and no current flows, i.e., I3=0A; the main circuit bears all the current, i.e., I2=25kA; at this time, the connecting module is in a closed state and almost no current flows through it, i.e., I4=0.1A.

[0073] There are two scenarios at this point. Scenario 1: Before starting to close:

[0074] That is, before the closing begins .

[0075] Scenario 2: 30ms after closing is complete at this time This is because the short-circuit withstand current is the same as the closing current.

[0076] Will .

[0077] Substitution middle achievable .

[0078] We can solve for τ = -0.022.

[0079] Right now .

[0080] 4. Similarly, during the opening and closing process... .

[0081] Right now It is a constant value.

[0082] Based on the y4 values ​​obtained in the above four cases, they can be used to predict the current value corresponding to the total current connection module at different inputs of the load switch under the four different cases.

[0083] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0084] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations to the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. An apparatus for coordinating the continuous current withstand and interrupting functions of a load break switch, comprising: The device includes: Disconnecting branch circuits, main circuits, linkage modules, and coordination modules; The linkage module is used to connect the moving contact of the disconnecting branch and the moving contact of the main circuit. When the load switch is in different states, the disconnecting branch and the main circuit bear the corresponding current. The coordination module is used to design the linkage module and determine the current value flowing through the linkage module based on the current value borne by the disconnecting branch and the main circuit at the current time. Finally, the real-time dynamic prediction of the main circuit current and the disconnecting branch current of the load switch in different states is realized. The coordination module includes: a stability analysis unit, a linkage module design unit, and a dynamic current distribution unit; The stability analysis unit is used to determine the current values ​​at the inlet of the disconnected branch and the main circuit, the current value at the moving contact of the main circuit, and the current value at the stationary contact of the moving contact of the disconnected branch based on the total input current and the current state of the load switch. Based on the above current values ​​and the simulation data or theoretical calculation data of computational fluid dynamics, the unit obtains the basic data of dynamic and thermal stability of the current at each position. The linkage module design unit is used to determine the starting positions of the main circuit moving contact and the branch circuit breaking moving contact, as well as the starting sequence of the main circuit moving contact and the branch circuit breaking moving contact, and to determine the mechanical structure parameters of the linkage module so that the linkage module can withstand the electrodynamic forces brought by the dynamic stability current, thermal stability current and short-circuit closing current. The dynamic current distribution unit is used to determine the real-time current of the linkage module based on the total input current, and then realize the dynamic prediction of the main circuit current and the interrupted branch current based on the different states of the load switch. The different states of the load switch include: normal withstand current condition, short-circuit withstand current condition, closing process, and opening process.

2. The apparatus of claim 1, wherein: The current paths for the disconnected branch and the main circuit that bear the corresponding current are as follows: Breaking branch: The current flows from the current input main line of the load switch through the arc-extinguishing chamber to the stationary contact of the breaking branch moving contact, and finally flows out of the breaking branch moving contact. Main circuit: The current flows from the current input main line of the load switch through the stationary contact of the moving contact of the main circuit, and then flows out of the moving contact of the main circuit.

3. The device for coordinating the continuous current withstand and interruption functions of a load switch according to claim 2, characterized in that: Determining the mechanical structure parameters for the linkage module includes: the linkage module uses a gear set or worm gear to realize the synchronous movement of the main circuit moving contact knife and the breaking branch moving contact knife, and by changing the gear ratio of the gear set or worm gear, the order of the main circuit moving contact knife and the breaking branch moving contact knife is changed, so that the main circuit moving contact knife and the breaking branch moving contact knife have a time interval when they move synchronously.

4. A coordination method based on the continuous current withstand and breaking functions of a load switch, characterized in that: The device for coordinating the continuous current withstand and interruption functions of a load switch according to any one of claims 1-3 specifically includes the following steps: Based on the total input current and the current state of the load switch, determine the current values ​​at the inlet of the disconnected branch and the main circuit, the current value at the moving contact of the main circuit, and the current value at the stationary contact of the moving contact of the disconnected branch. Based on the above current values ​​and the simulation data or theoretical calculation data of computational fluid dynamics, obtain the basic data of dynamic and thermal stability of the current at each position. Determine the starting positions of the main circuit moving contact and the branch circuit moving contact, as well as the starting sequence of the main circuit moving contact and the branch circuit moving contact, and determine the mechanical structure parameters for the linkage module so that the linkage module can withstand the electrodynamic forces brought about by the dynamic stability current, thermal stability current, and short-circuit closing current. The admittance of the corresponding line of the linkage module is determined based on the total input current, and the main circuit current and the breaking branch current are guided based on the different states of the load switch and different total input currents.

5. The coordination method according to claim 4, characterized in that: The determination of the admittance of the corresponding line of the linkage module based on the total input current, and the guidance of the main circuit current and the breaking branch current under different states of the load switch and different total input currents, includes: The current path formed by the main current input line, the interruption branch, the main circuit, and the linkage module is equivalent to a network diagram with four nodes. The line between the first and second nodes is the branch corresponding to the main current input line, the line between the second and third nodes is the interruption branch, the line between the second and fourth nodes is the main circuit, and the line between the third and fourth nodes is the linkage module. The admittances corresponding to the above four lines are denoted as y1, y2, y3, and y4, respectively, and the real-time currents are denoted as I1, I2, I3, and I4, respectively. Based on the connection relationship between nodes, the final node admittance matrix is ​​determined, and the relationship between the node voltage and the branch current is obtained based on the node voltage equation. By using the current conservation and voltage relationship of the second node, the static correlation between the admittance y4 of the linkage module and other admittances is obtained; Since I1 is different for different states, the first dynamic correlation relationship is formed between admittance y4 and other admittances under different states; Based on the adjustment relationship of the linkage module over time, a time function is introduced on the basis of the first dynamic correlation relationship to represent the second dynamic correlation relationship between the admittance y4 corresponding to the linkage module and other admittances.

6. The coordination method according to claim 5, characterized in that: The method of determining the admittance of the corresponding line of the linkage module based on the total input current, and guiding the main circuit current and breaking branch current under different states of the load switch and different total input currents, also includes: The current value of the load switch under four conditions is determined: normal withstand current condition, short circuit withstand current condition, closing process and opening process. That is, the input current value I1 at the first node. Therefore, under different conditions, the admittance y1 corresponds to different values, while the values ​​of admittance y2 and y3 remain unchanged, which are the overall admittances of the corresponding opening branch and the main circuit, respectively. Based on the current sharing relationship between the branch circuit and the main circuit when the load switch is in different states, assign corresponding current values ​​to I2 and I3; Based on the determined I1, I2, I3 and the second dynamic correlation, the values ​​of admittance y4 under different states are obtained; Based on the current admittance y4 value, guide the main circuit current and the breaking branch current under different load switch states and different total input currents.

7. The coordination method according to claim 6, characterized in that: The current sharing relationship between the branch circuit and the main circuit based on the load switch in different states includes: Under normal withstand current and short-circuit withstand current conditions, the current borne by the disconnecting branch is less than that borne by the main circuit; during the closing process, the disconnecting branch does not bear current, and the main circuit bears all current. After a few seconds after the closing process ends, it switches to the normal withstand current condition; during the opening process, the disconnecting branch bears all current, and the main circuit does not bear current.

8. The coordination method according to claim 7, characterized in that: The process of obtaining the admittance y4 values ​​under different states based on the determined I1, I2, I3 combined with the second dynamic correlation includes: Under normal withstand current conditions, short-circuit withstand current conditions, and during the breaking process, the current borne by the breaking branch and the main circuit under the action of the linkage module is determined based on the total current flowing into the total input. Different current values ​​at the linkage module are obtained based on the recommended values ​​under different states. The current values ​​are then substituted into the second dynamic correlation to obtain the corresponding admittance y4. The admittance y4 under the three states is a fixed value and does not change with time. During the closing process: the current borne by the branch circuit and the main circuit under the action of the linkage module is determined according to the total current flowing into the total input, and the current value at the linkage module is obtained according to the recommended value under the current state; At this point, before closing begins, the current value is input into the second dynamic correlation to determine the admittance y4 before closing begins; after closing is completed... Then, since the short-circuit withstand current and the closing current are the same, the admittance y4 after closing is obtained. The admittance y4 after closing is input into the second dynamic correlation to obtain the corresponding parameters of the time function, thereby determining the relationship between the admittance y4 and time in this state.

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