阅读说明：本技术 直流断路器、直流断路器用的机械断路装置、以及直流断路器用的半导体断路装置 (DC circuit breaker, mechanical breaking device for DC circuit breaker, and semiconductor breaking device for DC circuit breaker ) 是由 金谷和长 网田芳明 石黑崇裕 于 2018-05-14 设计创作，主要内容包括：实施方式的直流断路器具有机械断路部、半导体断路部以及换流装置。机械断路部具有至少1个机械断路单元和支承至少1个机械断路单元的绝缘支柱。机械断路单元具有至少1个单体断路部。单体断路部具有机械触点部、密闭容器、操作杆、操作机构。机械触点部具有固定触头以及可动触头。机械触点部被从大地电绝缘。密闭容器封入有机械触点部以及绝缘性气体。密闭容器被从大地电绝缘。操作杆连结于可动触头。操作杆从密闭容器的内部延伸至外部。操作机构连结于操作杆。操作机构使可动触头相对于固定触头接触/分离。操作机构与可动触头设定为相同电位。(The DC circuit breaker of the embodiment comprises a mechanical breaking part, a semiconductor breaking part and a commutation device. The mechanical breaking section has at least 1 mechanical breaking unit and an insulating support supporting the at least 1 mechanical breaking unit. The mechanical breaking unit has at least 1 single breaking part. The single body breaking part comprises a mechanical contact part, a closed container, an operating lever and an operating mechanism. The mechanical contact portion has a fixed contact and a movable contact. The mechanical contact portion is electrically insulated from ground. The sealed container is sealed with a mechanical contact portion and an insulating gas. The sealed container is electrically insulated from ground. The operating lever is coupled to the movable contact. The operation rod extends from the inside to the outside of the closed container. The operating mechanism is connected to the operating rod. The operating mechanism brings the movable contact into and out of contact with respect to the fixed contact. The operating mechanism and the movable contact are set to the same potential.)

1. A DC circuit breaker comprises a mechanical breaking unit, a semiconductor breaking unit and a converter device,

the mechanical breaking unit comprises at least 1 mechanical breaking unit and an insulating support for supporting the at least 1 mechanical breaking unit,

the mechanical breaking unit is provided with at least 1 single breaking part,

the single body breaking portion includes:

a mechanical contact point portion having a fixed contact and a movable contact and electrically insulated from ground;

a sealed container in which the mechanical contact portion and an insulating gas are sealed and which is electrically insulated from ground;

an operation lever connected to the movable contact and extending from the inside to the outside of the sealed container; and

an operating mechanism coupled to the operating lever, configured to bring the movable contact into and out of contact with the fixed contact, and set to the same potential as the movable contact,

the semiconductor breaking unit includes:

a semiconductor module including a semiconductor group in which a plurality of self-excited semiconductor elements are connected in series; and

surge suppressors connected in parallel to the semiconductor modules,

the converter device includes:

a converter circuit configured by connecting a pair of legs, each of which is formed by connecting a pair of self-excited semiconductor elements in series, in parallel with a capacitor; and

a commutation regulation reactor connected in series to the commutation circuit,

the mechanical breaking unit includes a current breaking contact and a high withstand voltage contact having a higher withstand voltage than the current breaking contact or having the same withstand voltage as the current breaking contact,

the at least 1 mechanical breaking unit further comprises a mechanical breaking unit support plate, the mechanical breaking unit support plate is configured for the at least 1 single breaking unit and is supported by the insulation support column,

the at least 1 single-body breaking part comprises a first single-body breaking part and a second single-body breaking part,

the first individual breaking unit constitutes one of the current breaking contact and the high withstand voltage contact,

the second individual disconnecting portion constitutes one of the current interrupting contact and the high withstand voltage contact,

the first individual breaking unit and the second individual breaking unit are arranged such that the operating levers are operated on the same straight line by the operating mechanism and the operating directions of the operating levers by the operating mechanism are opposite to each other, and the operating mechanisms are arranged such that the operating levers are opposed to each other,

at least a part of the sealed container of the first individual disconnecting unit is arranged outside the mechanical disconnecting unit support plate in the horizontal direction,

at least a part of the sealed container of the second individual disconnecting unit is arranged outside the mechanical disconnecting unit support plate in the horizontal direction,

the current breaking contact and the high withstand voltage contact are connected in series to form a mechanical contact module,

both ends of the above-mentioned mechanical contact module are connected to the direct current transmission system,

the commutation circuit and the commutation adjustment reactor are connected in parallel to the current breaking contact,

the commutation circuit is connected to the high withstand voltage contact side of the commutation regulation reactor,

the semiconductor module is connected in parallel to the high withstand voltage contact and the inverter circuit.

2. The direct current circuit breaker according to claim 1,

the at least 1 mechanical breaking unit includes a plurality of mechanical breaking units stacked in a vertical direction with respect to the insulating support,

the sealed containers of the first individual disconnecting unit and the second individual disconnecting unit of each of the plurality of mechanical disconnecting units are connected in series with each other by an intra-unit bus,

the plurality of mechanical breaking units include a first mechanical breaking unit and a second mechanical breaking unit adjacent to each other in the vertical direction,

a portion of the sealed container of the first individual disconnecting unit of the first mechanical disconnecting unit, which is disposed outside the mechanical disconnecting unit support plate in the horizontal direction, and a portion of the sealed container of the second individual disconnecting unit of the second mechanical disconnecting unit, which is disposed outside the mechanical disconnecting unit support plate in the horizontal direction, are connected in series to each other by an inter-unit bus.

3. The direct current circuit breaker according to claim 1 or 2,

the mechanical breaking unit support plate of the at least 1 mechanical breaking unit is made of a metal material and is set to the same potential as the operating mechanism.

4. The DC circuit breaker according to any one of claims 1 to 3,

the operating mechanism of the first individual breaking unit and the operating mechanism of the second individual breaking unit are in contact with each other.

5. The DC circuit breaker according to any one of claims 1 to 4,

both of the first individual disconnecting portion and the second individual disconnecting portion constitute one of the high withstand voltage contact and the current interrupting contact.

6. The direct current circuit breaker according to claim 1,

the cell disconnecting unit is arranged such that the direction of operation of the operating lever by the operating mechanism is along the direction in which the insulating support extends.

7. The DC circuit breaker according to any one of claims 1 to 6,

the insulating support is provided with a vibration damping member for absorbing vibration.

8. The direct current circuit breaker according to any one of claims 1 to 7,

the mechanical breaking part is arranged in a building,

the insulating support is suspended from the ceiling of the building.

9. The direct current circuit breaker according to any one of claims 1 to 8,

the semiconductor breaking unit includes a semiconductor breaking unit support plate disposed on at least one of the semiconductor module and the surge suppressor,

the commutation device includes a commutation device support plate on which at least one of the commutation circuit and the commutation adjustment reactor is disposed,

the mechanical breaking unit support plate is integrated with at least one of the semiconductor breaking unit support plate and the converter device support plate.

10. A mechanical circuit breaking device for a direct current circuit breaker, wherein,

comprising at least 1 mechanical breaking unit, an insulating support, a current breaking contact and a high withstand voltage contact,

the mechanical breaking unit is provided with at least 1 single breaking part,

the single body breaking portion includes:

a mechanical contact point portion having a fixed contact and a movable contact and electrically insulated from ground;

a sealed container in which the mechanical contact portion and an insulating gas are sealed and which is electrically insulated from ground;

an operation lever connected to the movable contact and extending from the inside to the outside of the sealed container; and

an operating mechanism coupled to the operating lever, configured to bring the movable contact into and out of contact with the fixed contact, and set to the same potential as the movable contact,

said insulating support supporting said at least 1 mechanical breaking unit,

the high withstand voltage contact has a higher withstand voltage performance than the current interruption contact or is equivalent to the current interruption contact,

the at least 1 mechanical breaking unit further comprises a mechanical breaking unit support plate, the mechanical breaking unit support plate is configured for the at least 1 single breaking unit and is supported by the insulation support column,

the at least 1 single-body breaking part comprises a first single-body breaking part and a second single-body breaking part,

the first individual breaking unit constitutes one of the current breaking contact and the high withstand voltage contact,

the second individual disconnecting portion constitutes one of the current interrupting contact and the high withstand voltage contact,

the first individual breaking unit and the second individual breaking unit are arranged such that the operating levers are operated on the same straight line by the operating mechanism and the operating directions of the operating levers by the operating mechanism are opposite to each other, and the operating mechanisms are arranged such that the operating levers are opposed to each other,

at least a part of the sealed container of the first individual disconnecting unit is arranged outside the mechanical disconnecting unit support plate in the horizontal direction,

at least a part of the sealed container of the second individual disconnecting unit is arranged outside the mechanical disconnecting unit support plate in the horizontal direction,

the current breaking contact and the high withstand voltage contact are connected in series to form a mechanical contact module,

the two ends of the mechanical contact module are connected to a direct current transmission system.

11. A semiconductor breaking device for a DC breaker, wherein,

comprises a plurality of semiconductor breaking units and insulating pillars,

the semiconductor breaking unit includes:

a semiconductor module including a semiconductor group in which a plurality of self-excited semiconductor elements are connected in series;

a surge suppressor connected in parallel to the semiconductor module; and

a semiconductor breaking unit support plate for disposing the semiconductor module and the surge suppressor,

the insulating support column supports the plurality of semiconductor breaking units,

the plurality of semiconductor breaking units are stacked in a plurality of layers with respect to the insulating support.

Technical Field

Embodiments of the present invention relate to a dc circuit breaker, a mechanical breaking device for a dc circuit breaker, and a semiconductor breaking device for a dc circuit breaker.

Background

The transmission efficiency of the direct-current transmission is higher than that of the alternating-current transmission. In contrast, the cost of dc transmission is higher with respect to the cost of introduction of the equipment. However, in the case of long-distance power transmission, marine power transmission, or the like, since the power transmission efficiency of dc power transmission is overwhelmingly high, if the additional operating cost is evaluated for the equipment cost, the cost of dc power transmission is low overall. Therefore, the dc transmission is used for transmission between 2 stations across the sea, for example. In recent years, in order to increase the ratio of generated power using renewable energy among generated power and to satisfy a larger power demand using renewable energy, a method has been studied in which offshore wind power generation, solar power generation in desert regions, or the like is used to generate large-scale power in a place away from a main power consumption place, i.e., an urban area, and to transmit power over a long distance. Along with this, it is planned to construct a dc transmission network in which a plurality of power supply sites and demand sites are connected.

When constructing a power transmission network that connects 3 or more sites, a device is required that can quickly disconnect a point of accident from a sound system when the power transmission network has a fault. In general, a mechanical contact type circuit breaker is used in an alternating current system. In the mechanical contact breaker, contacts are opened at a current zero point generated by an alternating current, and an insulating medium is blown toward an arc current between the contacts to break an accident current. In contrast, in the dc power transmission system, since no current zero point is generated in the fault current, it is difficult to rapidly break the fault current with the conventional mechanical contact breaker.

Therefore, as a semiconductor circuit breaker capable of individually breaking a direct current, a semiconductor circuit breaker using a plurality of self-excited semiconductor elements having self-extinguishing capability, such as an IGBT (insulated gate Bipolar Transistor), has been proposed. However, since all the transmitted electric power passes through the plurality of self-excited semiconductor elements all the time, a large conduction loss occurs, which leads to a reduction in the transmission efficiency during normal operation.

In order to solve this problem, a hybrid breaker has been proposed in which another semiconductor breaker is connected in parallel to a circuit in which a mechanical contact breaker and an auxiliary semiconductor breaker are connected in series. In this hybrid circuit breaker, the mechanical contact type circuit breaker and the auxiliary semiconductor circuit breaker are brought into an on state and the other semiconductor circuit breaker is brought into an off state during steady-state power transmission. Thus, the transmission current flows through the mechanical contact type circuit breaker and the auxiliary semiconductor circuit breaker.

When an accident occurs, the auxiliary semiconductor circuit breaker is brought into a disconnection state and an opening command is given to the mechanical contact type circuit breaker. When the auxiliary semiconductor breaker is brought into the disconnection state in this way, the fault current flowing through the path between the mechanical contact breaker and the auxiliary semiconductor breaker is transferred to the other semiconductor breaker. Further, after the opening operation of the mechanical contact type breaker is completed and the withstand voltage performance of the steady-state conducting path is secured, the other semiconductor breaker is opened, thereby completing the interruption of the fault current.

In such a hybrid breaker, the conduction loss at the time of steady-state energization is only the conduction loss of the auxiliary semiconductor breaker, and therefore, the conduction loss can be reduced as compared with a configuration in which the steady-state energization path is formed only as a semiconductor breaker capable of individually breaking a direct current as described above. However, since the conduction loss of the auxiliary semiconductor circuit breaker is still generated, the conduction loss of the hybrid circuit breaker is larger than that of a conventional mechanical contact type circuit breaker in which a steady-state conduction path is formed only by mechanical contacts.

Therefore, a direct current circuit breaker has been proposed in which a mechanical contact type circuit breaker is connected in parallel to a circuit in which a semiconductor circuit breaker and a commutation circuit formed of a half-bridge circuit are connected in series. In this dc circuit breaker, the mechanical contact type circuit breaker is in an on state and the semiconductor circuit breaker and the inverter circuit are in an off state during steady-state power transmission. Therefore, the transmission current in steady-state transmission flows only through the mechanical contact breaker.

When an accident occurs, an opening command is given to the mechanical contact breaker, the semiconductor breaker is brought into an on state, and a commutation command is given to the commutation circuit. Then, the commutation circuit causes a current to flow in a direction opposite to the fault current flowing through the mechanical contact breaker, and a zero point is generated in the current of the mechanical contact breaker, and the mechanical contact breaker is opened, whereby the fault current is commutated from the mechanical contact breaker to the semiconductor breaker and the commutation circuit. After the fault current has been converted, the semiconductor circuit breaker opens, whereby the breaking of the fault current is completed.

In such a dc circuit breaker, since the steady-state current carrying path is constituted only by a mechanical contact breaker, conduction loss can be greatly reduced,

a general mechanical contact type circuit breaker includes: a fixed contact and a movable contact provided to be able to contact/separate; a metal case enclosing the fixed contact and the movable contact inside; and an operating mechanism for driving the movable contact to contact with and separate from the fixed contact. The metal case is filled with an insulating medium. The metal case is grounded and electrically insulated from the fixed contact and the movable contact. The operating mechanism is grounded, is disposed outside the metal case, and is connected to the movable contact in the metal case via a seal rod penetrating the metal case and an insulating operating rod connected to the seal rod in the metal case.

However, with the increase in voltage of the dc power transmission system, the mechanical contact type circuit breaker needs to improve withstand voltage performance of each part. That is, in the above-described mechanical contact type circuit breaker, it is necessary to widen the distance between the fixed contact and the movable contact of the high voltage portion and the grounded metal case to perform electrical insulation as the voltage increases. In addition, when desired breaking performance cannot be obtained by 1 mechanical contact breaker with an increase in voltage, a plurality of mechanical contact breakers may be connected in series to improve the breaking performance. Even in this case, in all the mechanical contact breakers connected in series, it is necessary to widen the distance between the fixed contact and the movable contact of the high-voltage portion and the grounded metal case for electrical insulation. As a result, the mechanical contact type breaker becomes large. The dc circuit breaker is supposed to be applied to a platform constructed on the sea, and the construction cost of the platform may increase due to the large size of the mechanical contact type circuit breaker. In addition, as the voltage increases, the length of the insulating rod connecting the movable contact of the high-voltage portion and the grounded operating mechanism also increases. As a result, the mass of the movable part of the operating mechanism increases, and therefore, the speed of opening between the fixed contact and the movable contact may decrease, and the response of the breaking operation may decrease.

Disclosure of Invention

Problems to be solved by the invention

The present invention addresses the problem of providing a direct current breaker that can be easily increased in voltage, can be suppressed from being increased in size, and can ensure the response of the breaking operation, a mechanical breaking device for the direct current breaker, and a semiconductor breaking device for the direct current breaker.

Means for solving the problems

Drawings

Fig. 1 is a perspective view showing a dc circuit breaker according to a first embodiment.

Fig. 2 is a perspective view schematically showing a direct current breaker of the first embodiment.

Fig. 3 is a perspective view showing the mechanical disconnecting unit of the first embodiment.

Fig. 4 is a sectional view showing the high withstand voltage contact.

Fig. 5 is a cross-sectional view showing a current breaking contact.

Fig. 6 is a perspective view schematically showing the mechanical breaking unit of the first embodiment.

Fig. 7 is a perspective view showing the semiconductor breaking unit of the first embodiment.

Fig. 8 is a perspective view schematically showing the semiconductor breaking unit of the first embodiment.

Fig. 9 is a perspective view showing the inverter device of the first embodiment.

Fig. 10 is a circuit diagram showing a commutation circuit.

Fig. 11 is a perspective view schematically showing the inverter device of the first embodiment.

Fig. 12 is a circuit diagram schematically showing the dc circuit breaker of the first embodiment.

Fig. 13 is a cross-sectional view showing a modification of the high withstand voltage contact.

Fig. 14 is a front view schematically showing a mechanical breaking portion of the second embodiment.

Fig. 15 is a front view schematically showing a mechanical breaking portion of the third embodiment.

Fig. 16 is a front view schematically showing a mechanical breaking unit of the fourth embodiment.

Fig. 17 is a front view schematically showing a mechanical breaking unit of the fifth embodiment.

The DC circuit breaker of the embodiment comprises a mechanical breaking part, a semiconductor breaking part and a commutation device. The mechanical breaking unit includes: at least 1 mechanical breaking unit; and an insulating support supporting at least 1 mechanical breaking unit. The mechanical breaking unit has at least 1 single breaking part. The single body breaking part comprises a mechanical contact part, a closed container, an operating lever and an operating mechanism. The mechanical contact portion has a fixed contact and a movable contact. The mechanical contact portion is electrically insulated from ground. The sealed container is sealed with a mechanical contact portion and an insulating gas. The sealed container is electrically insulated from ground. The operating lever is coupled to the movable contact. The operation rod extends from the inside to the outside of the closed container. The operating mechanism is connected to the operating rod. The operating mechanism brings the movable contact into and out of contact with respect to the fixed contact. The operating mechanism and the movable contact are set to the same potential. The semiconductor circuit breaker includes a semiconductor module and a surge suppressor. The semiconductor module has a semiconductor group in which a plurality of self-excited semiconductor elements are connected in series. The surge suppressor is connected in parallel with the semiconductor module. The converter device has a converter circuit and a converter adjustment reactor. The inverter circuit is configured by connecting in parallel a pair of legs, which are formed by connecting a pair of self-excited semiconductor elements in series, and a capacitor. The commutation regulation reactor is connected in series with the commutation circuit. The mechanical breaking portion has a current breaking contact and a high withstand voltage contact. The high withstand voltage contact has a higher withstand voltage performance than the current interruption contact or the same level. At least 1 mechanical breaking unit also has a mechanical breaking section support plate. At least 1 single breaking part is arranged on the mechanical breaking part support plate. The mechanical breaking portion support plate is supported by the insulating support. The mechanical breaker support plate and the operating mechanism are set to the same potential. At least 1 single-body breaking part is provided with a first single-body breaking part and a second single-body breaking part. The first individual disconnecting portion forms either a current disconnecting contact or a high withstand voltage contact. The second individual disconnecting portion forms either a current disconnecting contact or a high withstand voltage contact. The respective operation levers of the first individual breaking unit and the second individual breaking unit are arranged to be operated on the same straight line by the operation mechanism. The first individual breaking unit and the second individual breaking unit are arranged such that the operating directions of the operating levers by the operating mechanism are opposite to each other. The first individual breaking unit and the second individual breaking unit have their operating mechanisms arranged to face each other. At least a part of the sealed container of the first individual disconnecting unit is arranged outside the mechanical disconnecting unit support plate in the horizontal direction. At least a part of the sealed container of the second individual disconnecting unit is arranged outside the mechanical disconnecting unit support plate in the horizontal direction. The current breaking contacts and the high withstand voltage contacts are connected in series to form a mechanical contact module. The two ends of the mechanical contact module are connected to the direct current transmission system. The commutation circuit and the commutation adjustment reactor are connected in parallel to the current breaking contact. The commutation circuit is connected to a higher withstand voltage contact side than the commutation regulation reactor. The semiconductor module is connected in parallel with the high withstand voltage contact and the inverter circuit.