Topological structure of zero-region residual magnetism compensation type circuit breaker and switching-on and switching-off method

Abstract

According to the topological structure of the zero-region residual magnetism compensation type circuit breaker and the breaking method, in the topological structure, a rapid vacuum switch S1 comprises a static contact and a moving contact, the static contact and the moving contact are separated to generate arc plasma, a compensation coil L1 is arranged on the periphery of the static contact and the moving contact in a sleeving mode, and the compensation coil L1 is connected with the static contact. A reverse longitudinal magnetic field is excited near a zero region to compensate a zero region residual magnetic field and accelerate dissipation of zero region residual plasma, and a compensation coil L1 is connected in series and reused in the transfer module; the transfer module is connected in parallel with the rapid vacuum switch S1 through the auxiliary switch S2; the energy consumption module is connected with the transfer module in parallel.

Description

Technical Field

[0001] The invention relates to the technical field of large-capacity circuit breakers, in particular to a topological structure and a breaking method of a zero-zone residual magnetism compensation type circuit breaker. Background Art

[0002] The generator output circuit breaker is a core power equipment installed between the generator set and the step-up transformer, which is of great significance for maintaining the safe and stable operation of the power system. The short-circuit current at the outlet of a large-capacity generator is very high, reaching 210kA and above, usually containing a huge DC component, prone to the phenomenon of delayed current zero crossing, and extremely high requirements for the circuit breaker's breaking capacity. Although the traditional current injection breaking technology can force the current to drop rapidly until the current crosses the zero point, due to the eddy current effect, there is still a large amount of residual magnetic field near the zero zone, which hinders the dissipation of the residual plasma in the zero zone, reduces the strength of the post-arc medium, and is not conducive to the breaking of large-capacity short-circuit currents.

[0003] The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0004] In view of the shortcomings or defects of the prior art, a topological structure and method of a zero-zone residual magnetic compensation circuit breaker are provided. During the rapid current transfer process, a reverse longitudinal magnetic field is synchronously applied to the contact system of the fast vacuum switch to offset the zero-zone residual magnetic field, accelerate the dissipation of the zero-zone residual plasma, and improve the reliability of large-capacity short-circuit current breaking. The method has the advantages of high breaking reliability, large breaking capacity, fast breaking speed, and environmental protection, and can better meet the application requirements of large-scale generator set protection.

[0005] The purpose of the present invention is achieved through the following technical solutions.

[0006] A topological structure of a zero-zone residual magnetic compensation circuit breaker includes: Zero zone residual magnetic compensation type vacuum switch module, comprising: The fast vacuum switch S1 includes a static contact and a moving contact. The static contact and the moving contact are separated to generate arc plasma. A compensation coil L1 is sleeved around the static contact and the moving contact, and excites a reverse longitudinal magnetic field near the zero zone to compensate for the residual magnetic field in the zero zone, thereby accelerating the dissipation of the residual plasma in the zero zone. The compensation coil L1 is serially connected and reused in the transfer module; A transfer module connected in parallel to the fast vacuum switch S1 via an auxiliary switch S2; An energy consumption module is connected in parallel with the transfer module.

[0007] In the topological structure of the zero-zone residual magnetism compensation type circuit breaker, both the static contact and the moving contact are contacts with a cup-shaped longitudinal magnetic structure.

[0008] In the topological structure of the zero-zone residual magnetic compensation type circuit breaker, the static contact includes: Static conductive rod, The static end contact cup is connected to the static conductive rod, and the static end contact cup is provided with a first inclined slot inclined in a predetermined inclined direction. The static end contact piece is arranged at one end of the static end contact cup relative to the static conductive rod, The moving contact includes: Moving conductive rod, The movable contact cup is connected to the movable conductive rod, and the movable contact cup is provided with a second inclined slot inclined in a predetermined inclined direction. The moving end contact piece is arranged at one end of the moving end contact cup relative to the moving conductive rod. The moving contact and the static contact switch between contact and separation. When current flows through the static contact, the vacuum arc and the moving contact, a longitudinal magnetic field that diffuses the vacuum arc is generated in the gap between the static contact and the moving contact.

[0009] In the topological structure of the zero-zone residual magnetism compensation circuit breaker, the transfer module includes a transfer capacitor C and a transfer inductor L2 connected in series at one end of the compensation coil L1 and a thyristor assembly provided at the other end of the compensation coil L1, and the thyristor assembly includes a thyristor T1 and a thyristor T2 connected in reverse parallel.

[0010] In the topological structure of the zero-zone residual magnetism compensation circuit breaker, the thyristor T1 and the thyristor T2 respectively include a plurality of thyristors connected in series.

[0011] In the topological structure of the zero-zone residual magnetism compensation type circuit breaker, the compensation coil L1 includes a single coil, a Helmholtz coil and a Maxwell coil.

[0012] In the topological structure of the zero-zone residual magnetic compensation type circuit breaker, the direction of the magnetic field generated by the excitation of the compensation coil L1 is opposite to the direction of the residual magnetic field of the contact gap near the zero zone.

[0013] In the topological structure of the zero-zone residual magnetic compensation circuit breaker, the fast vacuum switch S1 is driven by a fast operating mechanism, and the fast operating mechanism includes a spring operating mechanism and an electromagnetic repulsion mechanism.

[0014] In the topological structure of the zero-zone residual magnetic compensation circuit breaker, the auxiliary switch S2 includes any one of a gas switch, a vacuum switch, and a power electronic switch, or a combination of multiple ones.

[0015] The breaking method of the topological structure of the zero-zone residual magnetic compensation type circuit breaker includes the following steps: Step S100: When the fault current drops to a first characteristic value, a tripping signal is sent to the fast vacuum switch S1; Step S200: When the fault current drops to the second characteristic value, the thyristor assembly is triggered, and the transfer module injects a transfer current into the fast vacuum switch S1, the current of the fast vacuum switch S1 drops, the DC component of the fault current decays, and an artificial zero crossing point is generated. At the same time, the transfer current flows through the compensation coil L1, and a reverse longitudinal magnetic field is synchronously applied to the contact gap of the fast vacuum switch S1 to offset the residual magnetic field in the zero zone and accelerate the dissipation of the residual plasma in the zero zone. Step S300: the fast vacuum switch S1 is disconnected at zero crossing, the thyristor assembly is cut off at zero crossing, the fault current is limited by the energy consumption module, and a trip signal is sent to the auxiliary switch S2 to complete the fault current interruption.

[0016] Compared with the prior art, the present invention has the following beneficial effects: After detecting the fault current, the present invention controls the action of the fast vacuum switch and triggers the transfer module according to a predetermined timing, and finally realizes the fast limitation and disconnection of the delayed zero crossing of the large-capacity short-circuit current through fast current transfer, forced zero crossing, zero zone residual magnetism compensation and energy-consuming disconnection. In the process of rapid current transfer, a compensation coil is used to apply a reverse longitudinal magnetic field to the contact gap of the fast vacuum switch to offset the residual magnetic field in the zero zone, accelerate the dissipation of the residual plasma in the zero zone, and greatly reduce the probability of post-arc breakdown and reignition. At the same time, the fast vacuum disconnection technology is used to replace the traditional SF6 gas disconnection technology, which is completely environmentally friendly and has the characteristics of fast disconnection.

[0017] The above description is only an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and to achieve the extent that those skilled in the art can implement it according to the contents of the specification, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are exemplified below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0019] In the attached picture: Figure 1It is a schematic diagram of a topological structure of a circuit breaker for delayed zero crossing of a large-capacity short-circuit current provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of a cup-shaped contact structure of a fast vacuum switch and its self-generated longitudinal magnetic field provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of the waveform of the breaking current and the waveform of the magnetic field strength of the contact gap when the zero-zone residual magnetism compensation solution is not adopted, provided by an embodiment of the present invention; Figure 4 It is a schematic diagram of the waveform of the breaking current and the waveform of the magnetic field strength of the contact gap after adopting the zero-zone residual magnetism compensation solution provided by an embodiment of the present invention; Figure 5 This is a schematic diagram of the flow of a fast vacuum switch provided by an embodiment of the present invention when the contacts are closed and turned on; Figure 6 It is a schematic diagram of a fast vacuum switch provided by an embodiment of the present invention generating vacuum arc plasma after the contact is actuated; Figure 7 It is a schematic diagram of a contact gap of a fast vacuum switch provided by an embodiment of the present invention being applied with a reverse longitudinal magnetic field near a zero zone; Figure 8 It is a schematic diagram of the rapid diffusion of residual plasma in the contact gap of a fast vacuum switch provided by an embodiment of the present invention after the zero-zone residual magnetism compensation is achieved; Fig. 9 yes Figure 1 The normal current-carrying phase of the circuit breaker shown; Fig.10 yes Figure 1 The circuit breaker is shown in the arcing and rapid transfer stages of operation; Fig.11 yes Figure 1 Energy dissipation phase of the circuit breaker shown; Fig.12 yes Figure 1 The breaking phase of the circuit breaker shown; Fig.13 It is a schematic diagram of a topological structure based on parallel connection of multiple vacuum breaks provided by another embodiment of the present invention.

[0020] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0021] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0022] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0023] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0024] For a better understanding, Figures 1 to 13 As shown, a topological structure of a zero-zone residual magnetic compensation type circuit breaker includes: Zero zone residual magnetic compensation type vacuum switch module, comprising: The fast vacuum switch S1 includes a static contact and a moving contact. The static contact and the moving contact are separated to generate arc plasma. A compensation coil L1 is sleeved around the static contact and the moving contact, and excites a reverse longitudinal magnetic field near the zero zone to compensate for the residual magnetic field in the zero zone, thereby accelerating the dissipation of the residual plasma in the zero zone. The compensation coil L1 is serially connected and reused in the transfer module; A transfer module connected in parallel to the fast vacuum switch S1 via an auxiliary switch S2; An energy consumption module is connected in parallel with the transfer module.

[0025] In a preferred embodiment of the topological structure of the zero-zone residual magnetism compensation type circuit breaker, both the static contact and the moving contact are contacts with a cup-shaped longitudinal magnetic structure.

[0026] In a preferred embodiment of the topological structure of the zero-zone residual magnetic compensation type circuit breaker, the static contact comprises: Static conductive rod, The static end contact cup is connected to the static conductive rod, and the static end contact cup is provided with a first inclined slot inclined in a predetermined inclined direction. The static end contact piece is arranged at one end of the static end contact cup relative to the static conductive rod, The moving contact includes: Moving conductive rod, The movable contact cup is connected to the movable conductive rod, and the movable contact cup is provided with a second inclined slot inclined in a predetermined inclined direction. The moving end contact piece is arranged at one end of the moving end contact cup relative to the moving conductive rod. The moving contact and the static contact switch between contact and separation. When current flows through the static contact, the vacuum arc and the moving contact, a longitudinal magnetic field that diffuses the vacuum arc is generated in the gap between the static contact and the moving contact.

[0027] In a preferred embodiment of the topological structure of the zero-zone residual magnetism compensation type circuit breaker, the transfer module includes a transfer capacitor C and a transfer inductor L2 connected in series at one end of the compensation coil L1 and a thyristor assembly provided at the other end of the compensation coil L1, and the thyristor assembly includes a thyristor T1 and a thyristor T2 connected in reverse parallel.

[0028] In a preferred embodiment of the topological structure of the zero-zone residual magnetism compensation type circuit breaker, the thyristor T1 and the thyristor T2 respectively include a plurality of thyristors connected in series.

[0029] In a preferred embodiment of the topological structure of the zero-zone residual magnetism compensation type circuit breaker, the compensation coil L1 includes a single coil, a Helmholtz coil and a Maxwell coil.

[0030] In a preferred embodiment of the topological structure of the zero-zone residual magnetic compensation type circuit breaker, the direction of the magnetic field generated by the excitation of the compensation coil L1 is opposite to the direction of the residual magnetic field of the contact gap near the zero zone.

[0031] In a preferred embodiment of the topological structure of the zero-zone residual magnetic compensation circuit breaker, the fast vacuum switch S1 is driven by a fast operating mechanism, and the fast operating mechanism includes a spring operating mechanism and an electromagnetic repulsion mechanism.

[0032] In a preferred embodiment of the topological structure of the zero-zone residual magnetic compensation type circuit breaker, the auxiliary switch S2 includes any one of a gas switch, a vacuum switch, and a power electronic switch, or a combination of multiple thereof.

[0033] The breaking method of the topological structure of the zero-zone residual magnetic compensation type circuit breaker includes the following steps: Step S100: When the fault current drops to a first characteristic value, a tripping signal is sent to the fast vacuum switch S1; Step S200: When the fault current drops to the second characteristic value, the thyristor assembly is triggered, and the transfer module injects a transfer current into the fast vacuum switch S1, the current of the fast vacuum switch S1 drops, the DC component of the fault current decays, and an artificial zero crossing point is generated. At the same time, the transfer current flows through the compensation coil L1, and a reverse longitudinal magnetic field is synchronously applied to the contact gap of the fast vacuum switch S1 to offset the residual magnetic field in the zero zone and accelerate the dissipation of the residual plasma in the zero zone. Step S300: the fast vacuum switch S1 is disconnected at zero crossing, the thyristor assembly is cut off at zero crossing, the fault current is limited by the energy consumption module, and a trip signal is sent to the auxiliary switch S2 to complete the fault current interruption.

[0034] In the preferred embodiment of the breaking method, in step S100, when the fault current drops to the first characteristic value, a tripping command is sent to the fast vacuum switch S1. The first characteristic value ensures that the moving and static contacts of the fast vacuum switch reach a certain opening distance when the current transfers through zero, and cooperates with the zero zone residual magnetism compensation method to reliably withstand the transient recovery voltage after the arc.

[0035] In the preferred embodiment of the breaking method, in step S200, when the fault current drops to the second characteristic value, a turn-on signal is sent to the thyristor assembly, the transfer circuit is turned on, and the transfer capacitor C and the inductor oscillate to generate a high-frequency transfer current and inject it into the fast vacuum switch S1. In order to ensure that the current of the fast vacuum switch S1 reliably produces a zero crossing point, the second characteristic value needs to be less than the peak value of the transfer current, and generally a margin of 5kA~10kA needs to be left. At the same time, under the premise of ensuring that the current reliably crosses zero, the second characteristic value should be close to the minimum value of the fault current to reduce the amplitude requirement of the transfer current, which can not only reduce the pre-charge voltage of the transfer capacitor C, improve the service life of the transfer capacitor C and the transfer inductor L2, but also reduce the number of series and parallel connections of the thyristor assembly, saving prototype cost and space.

[0036] In one embodiment, a topological structure of a zero-zone residual magnetic compensation type large-capacity circuit breaker includes: Zero zone residual magnetic compensation type vacuum switch module, comprising: The fast vacuum switch S1 includes a static contact and a moving contact. The static contact and the moving contact are separated to generate arc plasma. A compensation coil L1, which is sleeved around the static contact and the moving contact, and can excite a reverse longitudinal magnetic field near the zero zone to compensate for the residual magnetic field in the zero zone, so as to accelerate the dissipation of the residual plasma in the zero zone, and the compensation coil L1 is serially reused in the transfer module; A transfer module connected in parallel to the fast vacuum switch S1 via an auxiliary switch S2; An energy consumption module is connected in parallel with the transfer module.

[0037] After the current of the traditional current injection circuit breaker is forced to pass through zero, due to the eddy current effect, there is a residual magnetic field in the contact gap, which makes it difficult for the residual plasma in the zero zone to dissipate quickly, reducing the strength of the dielectric tolerance after the arc, and is easily broken down and reignited by the transient recovery voltage. The topological structure of this zero-zone residual magnetic compensation type large-capacity circuit breaker can generate a reverse longitudinal magnetic field in the contact gap near the zero zone, weaken the strength of the residual magnetic field, accelerate the dissipation of the residual plasma in the zero zone, and enhance the dielectric tolerance of the fast vacuum switch after forced zero crossing, thereby improving the breaking reliability of the current injection circuit breaker and meeting the application requirements of large-scale generator protection.

[0038] In one embodiment, the energy dissipation resistor R includes any one of an aluminum shell resistor, a ceramic resistor, a wire winding resistor, and a cement resistor, or a combination of multiple thereof.

[0039] In one embodiment, a topological structure is shown in FIG1, including a zero-zone residual magnetism compensation type vacuum switch module, a transfer module, an energy consumption module and an auxiliary switch S2. The transfer module is connected in parallel at both ends of the zero-zone residual magnetism compensation type vacuum switch module through the auxiliary switch S2, and the energy consumption module is connected in parallel at both ends of the transfer module. Among them, the zero-zone residual magnetism compensation type vacuum switch module includes a fast vacuum switch S1 and a compensation coil L1; the transfer module includes a transfer capacitor C, a transfer inductor L2 and thyristor components T1 and T2, and the compensation coil L1 is serially reused in the transfer module; the energy consumption module includes an energy consumption resistor R.

[0040] In the embodiment of the present invention, the fast vacuum switch S1 adopts a contact with a cup-shaped longitudinal magnetic structure, as shown in FIG2, including a moving end contact cup 1, a moving end contact sheet 2, a static end contact sheet 3, a static end contact cup 4, a moving conductive rod 5 and a static conductive rod 6. Among them, the moving end contact cup 1 and the static end contact cup 4 are provided with inclined grooves in the same direction. When the current flows through "moving conductive rod 5-moving end contact cup 1-moving end contact sheet 2-vacuum arc 8-static end contact sheet 3-static end contact cup 4-static conductive rod 6", a longitudinal magnetic field 7 will be generated in the gap between the moving and static contacts. Under the action of the longitudinal magnetic field, the vacuum arc 8 is in a diffuse state, which can reduce the local ablation of the contact surface and help improve the current breaking capacity of the vacuum switch.

[0041] In the embodiment of the present invention, when the zero zone residual magnetism compensation scheme is not adopted, as shown in FIG3, due to the eddy current effect, the peak point of the magnetic field intensity of the contact gap obviously lags behind the current peak point, which results in the contact gap still having a residual magnetic field when the current approaches the zero point, and the residual magnetic field has a pinching effect on the arc plasma, which is not conducive to the dissipation of the residual plasma after the arc. When the zero zone residual magnetism compensation scheme is adopted, as shown in FIG4, near the current zero zone, a reverse longitudinal magnetic field is applied to the contact gap through the compensation coil L1, which greatly reduces the residual magnetic field when the current passes through zero, helps to dissipate the residual plasma, and improves the post-arc dielectric tolerance of the fast vacuum switch S1.

[0042] In the embodiment of the present invention, under normal flow condition, Figure 5 As shown, the moving contact and the static contact are in close contact, and the current flows from one end to the other end; when the fault current appears, the fast vacuum switch S1 receives the trip signal, and along with the separation of the moving and static contacts, a vacuum arc plasma is generated in the contact gap, which is mainly composed of a large number of ions, electrons and metal particles. Under the action of the longitudinal magnetic field 7 generated by the contact cup, the vacuum arc is in a diffuse state, as shown in FIG. Figure 6 As shown; when the current transfers rapidly and approaches the zero point, Figure 7 As shown, the compensation coil 9 synchronously generates a reverse longitudinal magnetic field 10, and the magnetic field 7 is in the opposite direction to the magnetic field 10, which cancels each other out. The residual magnetic field in the contact gap is quickly reduced to a lower level, such as Figure 8 As shown, at this time, the remaining plasma behind the arc quickly dissipates, and the post-arc dielectric withstand strength of the fast vacuum switch S1 is greatly improved.

[0043] In the embodiment of the present invention, the topological structure of the high current circuit breaker can realize bidirectional breaking, and the breaking process of the forward breaking can be divided into four stages in sequence, such as Figures 9 to 12 shown.

[0044] Fig. 9 This is the normal current flow stage of the circuit breaker. In this stage, the current flows into the right end of the circuit breaker and flows out from the left end after passing through the fast vacuum switch. The pre-charge polarity of the transfer capacitor C is positive on the left and negative on the right.

[0045] Fig.10 This is the arcing and rapid transfer stage of the circuit breaker. In this stage, when the controller detects a fault condition and the short-circuit current drops to the first characteristic value, it sends a trip signal to the fast vacuum switch S1, and the moving and static contacts separate to generate vacuum arc plasma. When the controller detects that the short-circuit current drops to the second characteristic value, it triggers the thyristor T2, and the transfer capacitor C and the inductor oscillate to generate a high-frequency transfer current, which is injected into the branch of the fast vacuum switch S1, causing the current flowing through the fast vacuum switch S1 to drop rapidly. At the same time, the transfer current flows through the compensation coil L1, and a reverse longitudinal magnetic field is applied to the contact gap of the fast vacuum switch S1, which offsets the longitudinal magnetic field generated by the contact, reduces the strength of the residual magnetic field, and accelerates the dissipation of the residual plasma in the zero zone, so that the fast vacuum switch S1 successfully withstands the transient recovery voltage after the arc, and the short-circuit current begins to transfer to the energy dissipation resistor R.

[0046] Fig.11 This is the energy dissipation stage of the circuit breaker. In this stage, as the thyristor T2 turns off at zero crossing, the short-circuit current is completely transferred to the energy dissipation module. The resistance of the energy dissipation resistor is relatively large, and it can quickly dissipate the short-circuit energy.

[0047] Fig.12This is the opening stage of the circuit breaker. In this stage, the short-circuit current has been limited to a lower level, and the controller sends a trip signal to the auxiliary switch S2 to successfully break the fault current.

[0048] Among them, the first characteristic value and the second characteristic value in the current breaking process are determined by the control strategy. The basic principle of selecting the first characteristic value is to ensure that the moving and static contacts of the fast vacuum switch S1 reach a certain opening distance when the current transfers through zero, and cooperate with the zero zone residual magnetism compensation method to reliably withstand the transient recovery voltage after the arc. In the actual circuit breaker operation, the setting of the control parameters also needs to consider factors such as the mechanical delay of the operating mechanism and the error of detection and identification; the basic principle of selecting the second characteristic value is that it needs to be less than the peak value of the transfer current. In order to ensure that the current of the fast vacuum switch S1 reliably produces a zero point, it is generally necessary to leave a margin of 5kA~10kA. At the same time, under the premise of ensuring that the current reliably passes through zero, the second characteristic value should be close to the minimum value of the fault current to reduce the amplitude requirement of the transfer current. This can not only reduce the pre-charge voltage of the transfer capacitor C, improve the service life of the transfer capacitor C and the transfer inductor L2, but also reduce the number of series and parallel thyristor components, saving prototype cost and space.

[0049] The circuit breaker can realize bidirectional breaking. When breaking in the reverse direction, the fault current flows in from the left end of the circuit breaker and flows out from the right end after passing through the fast vacuum switch S1. At this time, the pre-charge polarity of the transfer capacitor C is still positive on the left and negative on the right. The transfer current generated after the thyristor is turned on cannot force the current of the fast vacuum switch S1 to cross zero. Therefore, when a fault condition is detected, the thyristor T2 needs to be triggered in advance to release a half-cycle transfer current and change the polarity of the transfer capacitor C to negative on the left and positive on the right. The subsequent control strategy and breaking principle are basically the same as those for forward breaking, and will not be repeated here.

[0050] In another embodiment, the circuit breaker adopts a topological structure in which multiple vacuum breakers are connected in parallel, and the fast vacuum switch S1 is replaced by multiple vacuum breakers connected in parallel, or each vacuum break is regarded as a fast vacuum switch S1, as shown in FIG13 . For large-scale generator sets of one million kilowatts, the short-circuit current is as high as 210 kA and above, which far exceeds the breaking capacity of a single vacuum interrupter. Connecting multiple vacuum interrupters in parallel can improve the overall breaking capacity. Each vacuum break is equipped with a compensation coil L1, and each compensation coil L1 is connected in parallel. In order to improve the current sharing characteristics of the parallel vacuum breakers, the vacuum interrupters and compensation coils L1 used in parallel need to be products of the same model and the same batch.

[0051] In this embodiment, the application method of the circuit breaker includes the following steps: Step S100: When the controller detects that the fault current drops to a first characteristic value, a trip signal is synchronously sent to all vacuum switches of the vacuum multi-break parallel module S1; Step S200: When the controller detects that the fault current drops to the second characteristic value, the thyristor assembly is triggered, and the transfer module injects high-frequency transfer current into the vacuum multi-break parallel module S1. The current of each vacuum break branch drops rapidly, and the DC component decays rapidly, and the current crosses zero. At the same time, the transfer current flows through each compensation coil L1, and a reverse longitudinal magnetic field is synchronously applied to the contact gap of each vacuum break, which offsets the longitudinal magnetic field generated by the contact, accelerates the dissipation of the residual plasma in the zero zone, and enhances the dielectric tolerance of the vacuum break after the arc; Step S300: The vacuum multi-break parallel module S1 is disconnected at zero crossing, the thyristor assembly is cut off at zero crossing, and the fault current is limited by the energy consumption module. When the current is limited to a lower level, the controller sends a trip signal to the auxiliary switch S2 to complete the fault current interruption.

[0052] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0053] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A topological structure of a zero-zone residual magnetic compensation circuit breaker, characterized in that: These include, Zero zone residual magnetic compensation type vacuum switch module, comprising: The fast vacuum switch S1 includes a static contact and a moving contact. The static contact and the moving contact are separated to generate arc plasma. A compensation coil L1 is sleeved around the static contact and the moving contact, and excites a reverse longitudinal magnetic field near the zero zone to compensate for the residual magnetic field in the zero zone, thereby accelerating the dissipation of the residual plasma in the zero zone. The compensation coil L1 is serially connected and reused in the transfer module; A transfer module connected in parallel to the fast vacuum switch S1 via an auxiliary switch S2; An energy consumption module is connected in parallel with the transfer module.

2. The topological structure of the zero-zone residual magnetic compensation type circuit breaker according to claim 1, characterized in that: Preferably, both the stationary contact and the moving contact are contacts with a cup-shaped longitudinal magnetic structure.

3. The topological structure of the zero-zone residual magnetic compensation type circuit breaker according to claim 2, characterized in that: The stationary contacts include: Static conductive rod, The static end contact cup is connected to the static conductive rod, and the static end contact cup is provided with a first inclined slot inclined in a predetermined inclined direction. The static end contact piece is arranged at one end of the static end contact cup relative to the static conductive rod, The moving contact includes: Moving conductive rod, The movable contact cup is connected to the movable conductive rod, and the movable contact cup is provided with a second inclined slot inclined in a predetermined inclined direction. The moving end contact piece is arranged at one end of the moving end contact cup relative to the moving conductive rod. The moving contact and the static contact switch between contact and separation. When current flows through the static contact, the vacuum arc and the moving contact, a longitudinal magnetic field that diffuses the vacuum arc is generated in the gap between the static contact and the moving contact.

4. The topological structure of the zero-zone residual magnetic compensation type circuit breaker according to claim 1, characterized in that: The transfer module includes a transfer capacitor C and a transfer inductor L2 connected in series at one end of the compensation coil L1 and a thyristor assembly provided at the other end of the compensation coil L1. The thyristor assembly includes a thyristor T1 and a thyristor T2 connected in reverse parallel.

5. The topological structure of the zero-zone residual magnetic compensation type circuit breaker according to claim 4, characterized in that: The thyristor T1 and the thyristor T2 each include a plurality of thyristors connected in series.

6. The topological structure of the zero-zone residual magnetic compensation type circuit breaker according to claim 1, characterized in that: The compensation coil L1 includes a single coil, a Helmholtz coil and a Maxwell coil.

7. The topological structure of the zero-zone residual magnetic compensation type circuit breaker according to claim 1, characterized in that: The direction of the magnetic field generated by the excitation of the compensation coil L1 is opposite to the direction of the residual magnetic field of the contact gap near the zero zone.

8. The topological structure of the zero-zone residual magnetic compensation type circuit breaker according to claim 1, characterized in that: The fast vacuum switch S1 is driven by a fast operating mechanism, which includes a spring operating mechanism and an electromagnetic repulsion mechanism.

9. The topological structure of the zero-zone residual magnetic compensation type circuit breaker according to claim 1, characterized in that: The auxiliary switch S2 includes any one of a gas switch, a vacuum switch, and a power electronic switch, or a combination of multiple switches.

10. A method for breaking the topological structure of the zero-zone residual magnetic compensation type circuit breaker according to any one of claims 1 to 9.

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