Topological structure and breaking method of zero-region residual magnetism compensation type circuit breaker

Abstract

Disclosed are a topology structure and a breaking method of a zero-region residual magnetism compensation type circuit breaker. In the topology structure, a fast vacuum switch S1 includes a static contact and a dynamic contact, the static contact and the dynamic contact are separated to generate arc plasma, a compensation coil L1 is sleeved on the periphery of the static contact and the dynamic contact, a reverse longitudinal magnetic field is excited near a zero region to compensate for a zero-region residual magnetic field, to accelerate the dissipation of zero-region residual plasma, and the compensation coil L1 is reused in a transfer module in series; a transfer module is connected in parallel with the fast vacuum switch S1 through an auxiliary switch S2; and an energy consumption module is connected in parallel with the transfer module.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of large-capacity circuit breaker, in particular to a topology structure and breaking method of zero-zone residual magnetic compensation type circuit breaker. BACKGROUND

[0002] Generator outlet circuit breaker is a core power equipment installed between generator set and step-up transformer, which is of great significance to maintain the safe and stable operation of power system. The short-circuit current of large-capacity generator outlet is very high, which can reach 210kA or above, usually containing a huge DC component, which is prone to current delay zero phenomenon, and the requirement for breaking capacity of circuit breaker is extremely high. Although the traditional current injection breaking technology can force the current to drop rapidly until the current zero point appears, 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 zero-zone residual plasma, reduces the strength of arc-after medium resistance, and is not conducive to the breaking of large-capacity short-circuit current.

[0003] The information disclosed in the background section merely serves to enhance the understanding of the background of the present application, and therefore can contain information that is not prior art known to those of ordinary skill in the art. SUMMARY

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

[0005] The purpose of the present application is achieved by the following technical solutions.

[0006] A topology structure of zero-zone residual magnetic compensation type circuit breaker comprises,

[0007] A zero-zone residual magnetic compensation type vacuum switch module comprises,

[0008] A fast vacuum switch S1 comprises a static contact and a moving contact, and the static contact and the moving contact are separated to generate arc plasma,

[0009] A compensation coil L1 is sleeved around the static contact and the moving contact, and a reverse longitudinal magnetic field is excited near the zero zone to offset the zero-zone residual magnetic field and accelerate the dissipation of zero-zone residual plasma, and the compensation coil L1 is reused in the transfer module in series;

[0010] A transfer module is connected in parallel to the fast vacuum switch S1 via an auxiliary switch S2.

[0011] An energy consumption module is connected in parallel with the transfer module.

[0012] In the topological structure of the zero-zone residual magnetism compensation type circuit breaker, both the static contact and the moving contact adopt a cup-shaped longitudinal magnetic structure.

[0013] In the topological structure of the zero-zone residual magnetism compensation type circuit breaker, the static contact includes:

[0014] Static conductive rod,

[0015] 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.

[0016] The static end contact piece is provided at one end of the static end contact cup relative to the static conductive rod.

[0017] The moving contact includes:

[0018] Moving conductive rod,

[0019] The movable end contact cup is connected to the movable conductive rod, and the movable end contact cup is provided with a second inclined slot inclined in a predetermined inclined direction.

[0020] 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.

[0021] 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. The thyristor assembly includes a thyristor T1 and a thyristor T2 connected in reverse parallel.

[0022] In the topological structure of the zero-zone residual magnetism compensation circuit breaker, the thyristor T1 and the thyristor T2 each include a plurality of thyristors connected in series.

[0023] 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.

[0024] In the topological structure of the zero-zone residual magnetism 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.

[0025] In the topological structure of the zero-zone residual magnetism compensation circuit breaker, the fast vacuum switch S1 is driven by a fast operating mechanism, which includes a spring operating mechanism and an electromagnetic repulsion mechanism.

[0026] The auxiliary switch S2 includes any one or a combination of a gas switch, a vacuum switch and a power electronic switch.

[0027] The breaking method of the topology structure of the zero-region residual magnetic compensation type circuit breaker comprises the following steps,

[0028] Step S100: when the fault current drops to a first characteristic value, a breaking signal is sent to the fast vacuum switch S1.

[0029] Step S200: when the fault current drops to a second characteristic value, a thyristor assembly is triggered, a transfer module injects a transfer current to the fast vacuum switch S1, the current of the fast vacuum switch S1 drops, the direct current component of the fault current decays, an artificial zero point is generated, and at the same time, the transfer current flows through the compensation coil L1, a reverse longitudinal magnetic field is synchronously applied to the contact gap of the fast vacuum switch S1, the zero-region residual magnetic field is offset, and the dissipation of the zero-region residual plasma is accelerated.

[0030] Step S300: the fast vacuum switch S1 breaks at zero, the thyristor assembly breaks at zero, the fault current is limited by an energy consumption module, a breaking signal is sent to the auxiliary switch S2, and the breaking of the fault current is completed.

[0031] Compared with the prior art, the present application has the following beneficial effects:

[0032] After detecting the fault current, the present application controls the fast vacuum switch and triggers the transfer module according to a predetermined timing sequence, realizes the fast limitation and breaking of the delay zero of the large-capacity short-circuit current through the fast current transfer, forced zero, zero-region residual magnetic compensation and energy consumption breaking. In the process of fast current transfer, the compensation coil is used to apply a reverse longitudinal magnetic field to the contact gap of the fast vacuum switch, offset the zero-region residual magnetic field, and accelerate the dissipation of the zero-region residual plasma, thereby greatly reducing the probability of arc-afterbreak reignition. At the same time, the fast vacuum breaking technology is used to replace the traditional SF6 gas breaking technology, which is completely environmentally friendly and fast in breaking.

[0033] The above description is only a summary of the technical scheme of the present application, in order to make the technical means of the present application more clear and understandable, to the extent that the content of the description can be implemented by the person skilled in the art, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described below. BRIEF DESCRIPTION OF DRAWINGS

[0034] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are intended only to illustrate preferred embodiments and are not to be construed as limiting the present invention. It should be understood that the drawings described below are merely examples of the present invention, and that those skilled in the art will be able to derive other drawings from these drawings without inventive effort. Throughout the drawings, identical reference numerals are used to denote identical components.

[0035] In the attached figure:

[0036] Figure 1 This 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;

[0037] Figure 2 Schematic diagram of a cup-shaped contact structure and its self-generated longitudinal magnetic field of a fast vacuum switch provided by one embodiment of the present invention;

[0038] Figure 3 1 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;

[0039] Figure 4 This 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 one embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of the flow of a fast vacuum switch provided by one embodiment of the present invention when the contacts are closed and conducting;

[0041] Figure 6 This is a schematic diagram of a fast vacuum switch according to an embodiment of the present invention generating vacuum arc plasma after contact operation;

[0042] Figure 7 This is a schematic diagram of a fast vacuum switch provided by one embodiment of the present invention having a contact gap of the switch subjected to a reverse longitudinal magnetic field near the zero zone;

[0043] Figure 8 This is a schematic diagram of the rapid diffusion of residual plasma in the contact gap of a fast vacuum switch provided by one embodiment of the present invention after zero-zone residual magnetism compensation is achieved;

[0044] Figure 9 yes Figure 1 The circuit breaker is shown in the normal flow phase;

[0045] Figure 10 yes Figure 1 The circuit breaker is shown in the arcing and rapid transfer stages of operation;

[0046] Figure 11 yes Figure 1 Energy consumption phase of the circuit breaker shown;

[0047] Figure 12 yes Figure 1 The breaking phase of the circuit breaker shown;

[0048] Figure 13 This is a schematic diagram of a topological structure based on parallel connection of multiple vacuum fractures provided by another embodiment of the present invention.

[0049] The present invention will be further explained below with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0050] Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although 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. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0051] 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 invention. The scope of protection of the present invention shall be as defined in the attached claims.

[0052] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings. However, the accompanying drawings do not limit the embodiments of the present invention.

[0053] For better understanding, Figures 1 to 13 As shown, a topological structure of a zero-zone residual magnetism compensation type circuit breaker includes:

[0054] Zero zone residual magnetism compensation type vacuum switch module, comprising:

[0055] The fast vacuum switch S1 includes a static contact and a moving contact. When the static contact and the moving contact separate, arc plasma is generated.

[0056] The compensation coil L1 is sleeved around the outer periphery of the static contact and the movable 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 reused in the transfer module;

[0057] A transfer module connected in parallel to the fast vacuum switch S1 via an auxiliary switch S2;

[0058] An energy consumption module is connected in parallel with the transfer module.

[0059] In a preferred embodiment of the topological structure of the zero-zone residual magnetism compensation type circuit breaker, both the static contact and the movable contact adopt cup-shaped longitudinal magnetic structure contacts.

[0060] In a preferred embodiment of the topological structure of the zero-zone residual magnetism compensation type circuit breaker, the static contact includes:

[0061] Static conductive rod,

[0062] 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.

[0063] The static end contact piece is provided at one end of the static end contact cup relative to the static conductive rod.

[0064] The moving contact includes:

[0065] Moving conductive rod,

[0066] The movable end contact cup is connected to the movable conductive rod, and the movable end contact cup is provided with a second inclined slot inclined in a predetermined inclined direction.

[0067] 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.

[0068] In a preferred embodiment of 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.

[0069] 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 each include a series connection of multiple thyristors.

[0070] 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.

[0071] In a preferred embodiment of the topological structure of the zero-zone residual magnetism 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.

[0072] In a preferred embodiment of the topological structure of the zero-zone residual magnetism compensation type circuit breaker, the fast vacuum switch S1 is driven by a fast operating mechanism, which includes a spring operating mechanism and an electromagnetic repulsion mechanism.

[0073] In a preferred embodiment of the topological structure of the zero-zone residual magnetism 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.

[0074] The breaking method of the topological structure of the zero-zone residual magnetic compensation type circuit breaker includes the following steps:

[0075] Step S100: When the fault current drops to a first characteristic value, a tripping signal is sent to the fast vacuum switch S1;

[0076] Step S200: When the fault current drops to a 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 decreases, and the DC component of the fault current decays, generating an artificial zero crossing. Simultaneously, the transfer current flows through the compensation coil L1, synchronously applying a reverse longitudinal magnetic field to the contact gap of the fast vacuum switch S1, thereby offsetting the residual magnetic field in the zero zone and accelerating the dissipation of the residual plasma in the zero zone.

[0077] 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.

[0078] In a preferred embodiment of the interruption method, in step S100, when the fault current drops to a first characteristic value, a trip command is sent to the fast-acting vacuum switch S1. This first characteristic value ensures that the moving and static contacts of the fast-acting vacuum switch reach a certain opening distance when the current transitions through zero. This, in conjunction with the zero-zone residual magnetism compensation method, reliably withstands the transient recovery voltage after an arc.

[0079] In a preferred embodiment of the disconnection method, in step S200, when the fault current drops to the second characteristic value, a turn-on signal is sent to the thyristor assembly, turning on the transfer circuit. The transfer capacitor C oscillates with the inductor to generate a high-frequency transfer current, which is then injected into the fast vacuum switch S1. To ensure that the current of the fast vacuum switch S1 reliably crosses zero, the second characteristic value needs to be less than the peak value of the transfer current, generally requiring a margin of 5kA to 10kA. At the same time, while 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 for the transfer current. This not only reduces the pre-charge voltage of the transfer capacitor C and increases the service life of the transfer capacitor C and the transfer inductor L2, but also reduces the number of thyristor assemblies connected in series and parallel, saving prototype cost and space.

[0080] In one embodiment, a topology structure of a zero-zone residual magnetism compensation type large-capacity circuit breaker includes:

[0081] Zero zone residual magnetism compensation type vacuum switch module, comprising:

[0082] The fast vacuum switch S1 includes a static contact and a moving contact. When the static contact and the moving contact separate, arc plasma is generated.

[0083] A compensation coil L1 is sleeved around the static contact and the movable contact, and is capable of exciting 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 reused in the transfer module;

[0084] A transfer module connected in parallel to the fast vacuum switch S1 via an auxiliary switch S2;

[0085] An energy consumption module is connected in parallel with the transfer module.

[0086] In traditional current injection circuit breakers, after the current is forced through zero, a residual magnetic field exists in the contact gap due to eddy currents. This makes it difficult for the residual plasma in the zero zone to dissipate quickly, reducing the dielectric withstand strength after the arc and making it susceptible to breakdown and reignition due to transient recovery voltage. The topology of this zero-zone residual magnetic compensation large-capacity circuit breaker generates a reverse longitudinal magnetic field in the contact gap near the zero zone, weakening the residual magnetic field, accelerating the dissipation of the residual plasma in the zero zone, and enhancing the dielectric withstand strength of the fast vacuum switch after forced zero crossing. This improves the interrupting reliability of the current injection circuit breaker and meets the application requirements of large-scale generator set protection.

[0087] In one embodiment, the energy dissipation resistor R includes any one of an aluminum shell resistor, a ceramic resistor, a wire wound resistor, and a cement resistor, or a combination of multiple thereof.

[0088] In one embodiment, a topological structure is shown in Figure 1, comprising a zero-zone residual magnetism compensation vacuum switch module, a transfer module, an energy consumption module, and an auxiliary switch S2. The transfer module is connected in parallel across the zero-zone residual magnetism compensation vacuum switch module via the auxiliary switch S2, and the energy consumption module is connected in parallel across the transfer module. The zero-zone residual magnetism compensation 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 assemblies T1 and T2. The compensation coil L1 is serially connected and reused in the transfer module; and the energy consumption module includes an energy consumption resistor R.

[0089] In an embodiment of the present invention, a fast-acting vacuum switch S1 employs contacts with a cup-shaped longitudinal magnetic structure, as shown in Figure 2. The contacts include a moving contact cup 1, a moving contact plate 2, a stationary contact plate 3, a stationary contact cup 4, a moving conductive rod 5, and a stationary conductive rod 6. The moving contact cup 1 and the stationary contact cup 4 have inclined slots extending in the same direction. When current flows through the "moving conductive rod 5 - moving contact cup 1 - moving contact plate 2 - vacuum arc 8 - stationary contact plate 3 - stationary contact cup 4 - stationary conductive rod 6" sequence, a longitudinal magnetic field 7 is generated between the moving and stationary contacts. Under the influence of this longitudinal magnetic field, the vacuum arc 8 assumes a diffused state, reducing localized erosion of the contact surfaces and helping to improve the current-breaking capability of the vacuum switch.

[0090] In an 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 in the contact gap significantly lags behind the current peak point. This results in the presence of a residual magnetic field in the contact gap when the current approaches the zero-crossing point. 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 by the compensation coil L1, which significantly reduces the residual magnetic field when the current crosses zero, helps dissipate the residual plasma, and improves the post-arc dielectric tolerance of the fast vacuum switch S1.

[0091] In the embodiment of the present invention, under normal flow state, as Figure 5 As shown in the figure, 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 the moving and static contacts separate. 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 diffusion state, as shown in the figure. Figure 6 As shown; when the current transfers quickly and approaches the zero point, as shown Figure 7 As shown, the compensation coil 9 generates a reverse longitudinal magnetic field 10 synchronously, 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 low level, as shown in FIG. Figure 8As shown in FIG, at this time, the remaining plasma after the arc quickly dissipates, and the post-arc dielectric withstand strength of the fast vacuum switch S1 is greatly improved.

[0092] In the embodiment of the present invention, the topology of the high current circuit breaker can realize bidirectional breaking, and the breaking process of the forward breaking can be divided into four stages, such as Figures 9 to 12 shown.

[0093] Figure 9 This is the normal flow phase of the circuit breaker. During this phase, current flows into the right end of the circuit breaker and flows out of 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.

[0094] Figure 10 This is the arcing and rapid transfer phase of the circuit breaker. During this phase, when the controller detects a fault and the short-circuit current drops to a first characteristic value, it sends a trip signal to the fast vacuum switch S1, separating the moving and static contacts and generating vacuum arc plasma. When the controller detects that the short-circuit current has dropped to a second characteristic value, it triggers thyristor T2. The transfer capacitor C oscillates with the inductor 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. Simultaneously, the transfer current flows through the compensation coil L1, applying a reverse longitudinal magnetic field across the contact gap of the fast vacuum switch S1. This counteracts the longitudinal magnetic field generated by the contacts, reducing the strength of the residual magnetic field and accelerating the dissipation of the residual plasma in the zero zone. This allows the fast vacuum switch S1 to successfully withstand the transient recovery voltage after the arc, and the short-circuit current begins to transfer to the energy-dissipating resistor R.

[0095] Figure 11 This is the energy dissipation phase of the circuit breaker. During this phase, as thyristor T2 turns off at zero crossing, the short-circuit current is completely transferred to the energy dissipation module. The energy dissipation resistor has a relatively large resistance value and can quickly dissipate the short-circuit energy.

[0096] Figure 12 This is the opening stage of the circuit breaker. During this stage, the short-circuit current has been limited to a lower level. The controller sends a trip signal to the auxiliary switch S2, successfully breaking the fault current.

[0097] The first and second eigenvalues ​​during the current interruption process are determined by the control strategy. The rationale for selecting the first eigenvalue 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 in conjunction with the zero-zone residual magnetism compensation method, to reliably withstand the transient recovery voltage after the arc. In actual circuit breaker operation, the setting of control parameters also needs to consider factors such as the mechanical delay of the operating mechanism and detection and identification errors. The rationale for selecting the second eigenvalue is that it must be less than the peak value of the transfer current. To ensure that the current of the fast vacuum switch S1 reliably passes through zero, a margin of 5kA to 10kA is generally required. Furthermore, while ensuring that the current reliably passes through zero, the second eigenvalue should be close to the minimum value of the fault current to reduce the amplitude requirement for the transfer current. This not only reduces the precharge voltage of the transfer capacitor C and improves the service life of the transfer capacitor C and the transfer inductor L2, but also reduces the number of series and parallel thyristor components, saving prototype cost and space.

[0098] The circuit breaker can achieve bidirectional disconnection. When disconnecting in the reverse direction, the fault current flows into the left end of the circuit breaker and flows out of 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 half a cycle of transfer current and reverse the polarity of the transfer capacitor C to negative on the left and positive on the right. The subsequent control strategy and disconnection principle are basically the same as those for forward disconnection and will not be repeated here.

[0099] 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 or 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 must be products of the same model and the same batch.

[0100] In this embodiment, the application method of the circuit breaker includes the following steps:

[0101] Step S100: When the controller detects that the fault current drops to a first characteristic value, it synchronously sends a trip signal to all vacuum switches of the fast vacuum switch S1;

[0102] Step S200: When the controller detects that the fault current has dropped to a second characteristic value, it triggers the thyristor assembly, and the transfer module injects a high-frequency transfer current into the fast vacuum switch S1. The current in each vacuum interrupter branch drops rapidly, and the DC component decays rapidly, resulting in a current zero crossing. Simultaneously, the transfer current flows through each compensation coil L1, synchronously applying a reverse longitudinal magnetic field to the contact gap of each vacuum interrupter. This counteracts the longitudinal magnetic field generated by the contacts, accelerating the dissipation of residual plasma in the zero zone and enhancing the dielectric resistance of the vacuum interrupter after the arc.

[0103] Step S300: The fast vacuum switch S1 switches off at zero crossing, the thyristor assembly switches 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, completing the fault current interruption.

[0104] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0105] The above description has been provided for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A topological structure of a zero-zone residual magnetism compensation type circuit breaker, characterized in that: It includes, Zero zone residual magnetism compensation type vacuum switch module, comprising: The fast vacuum switch S1 includes a static contact and a moving contact. When the static contact and the moving contact separate, arc plasma is generated. The compensation coil L1 is sleeved around the outer periphery of the static contact and the movable 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 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 magnetism compensation type circuit breaker according to claim 1, characterized in that: The static contact and the moving contact both adopt contacts with a cup-shaped longitudinal magnetic structure.

3. The topological structure of the zero-zone residual magnetism compensation type circuit breaker according to claim 2, characterized in that: 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 provided at one end of the static end contact cup relative to the static conductive rod. The moving contact includes: Moving conductive rod, The movable end contact cup is connected to the movable conductive rod, and the movable end 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 topology structure of the zero-zone residual magnetism 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 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 topology structure of the zero-zone residual magnetism 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 topology structure of the zero-zone residual magnetism 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 topology structure of the zero-zone residual magnetism 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 in the contact gap near the zero zone.

8. The topology structure of the zero-zone residual magnetism 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 topology structure of the zero-zone residual magnetism 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 thereof.

10. A method for breaking the topological structure of the zero-zone residual magnetism compensation type circuit breaker according to any one of claims 1 to 9, characterized in that: It includes, 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 a 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 decreases, and the DC component of the fault current decays, generating an artificial zero crossing. Simultaneously, the transfer current flows through the compensation coil L1, synchronously applying a reverse longitudinal magnetic field to the contact gap of the fast vacuum switch S1, thereby offsetting the residual magnetic field in the zero zone and accelerating 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.

Images