WO2021119938A1

WO2021119938A1 - Hybrid circuit breaker, hybrid circuit breaker system, and circuit breaker method

Info

Publication number: WO2021119938A1
Application number: PCT/CN2019/125698
Authority: WO
Inventors: 杜峰; 贝克特·托马斯; 姚远; 庞建国
Original assignee: 西门子股份公司; 西门子（中国）有限公司
Priority date: 2019-12-16
Filing date: 2019-12-16
Publication date: 2021-06-24
Also published as: CN114667657A; CN114667657B; DE112019007884T5

Abstract

A hybrid circuit breaker (100), a hybrid circuit breaker system, and a circuit breaker method. The hybrid circuit breaker (100) comprises: a first mechanical contact (MC1); a semiconductor circuit breaker (MSS), which is connected to the first mechanical contact (MC1); an energy absorber (AC), which is connected in parallel to the semiconductor circuit breaker (MSS); a second mechanical contact (MC2), which is connected to the other end of the semiconductor circuit breaker (MSS); an auxiliary semiconductor circuit breaker (ASS), which is connected in parallel to the second mechanical contact (MC2); and a controller. When a power system experiences a ground fault, the controller controls the semiconductor circuit breaker (MSS) to disconnect, then controls the second mechanical contact (MC2) to disconnect, then controls the auxiliary semiconductor circuit breaker (ASS) to close before the second mechanical contact (MC2) is disconnected and to disconnect after the second mechanical contact (MC2) is disconnected, and then controls the first mechanical contact (MC1) to disconnect. The hybrid circuit breaker may be safely operated and has lower costs.

Description

Hybrid circuit breaker, hybrid circuit breaker system and circuit breaker method

Technical field

The present invention relates to the field of power systems, in particular to a hybrid circuit breaker, a hybrid circuit breaker system and a circuit breaker method.

Background technique

In order to protect the power grid, solid state circuit breakers (SSCB, solid state circuit breakers) will be used for short circuit and grounding protection. However, the existing technology mainly has two application challenges. First, due to the strong background residual current possible even without a ground fault system, the ground fault current can be difficult to detect. Secondly, the solid-state circuit breaker cannot cut off the ground fault current due to the possible large capacitance in it.

Among them, the current will be transmitted in the solid-state circuit breaker, if the transmission current is directly interrupted, the mechanical contact will be damaged. Usually, the transmission current will be ±4A. However, such transmission current will be transmitted through off-the-shelf low-cost semiconductor switches, such as low-rated current semiconductor switches such as SI-MOSFET, IGBT, and SIC MOSFET. In addition, the parasitic capacitance of a single chip is about 100pF. If the chip is cut off, the parasitic capacitance will limit high-frequency components.

Generally, if the background residual current is strong in the system, the first challenge is to always bypass the residual current by not introducing a residual protection function. The second challenge is that if a component with a small parasitic capacitance is selected, and a TVS-based snubber circuit is used together to replace the current limiting resistor snubber circuit (RC snubber circuit), the cost and size of the entire circuit will increase a lot. Moreover, even if a resistor snubber circuit is used, the high-frequency residual current cannot be cut off.

Summary of the invention

The first aspect of the present invention provides a hybrid circuit breaker, which includes: a first mechanical contact; a semiconductor circuit breaker connected to the first mechanical contact; and an energy absorber connected in parallel to the semiconductor circuit breaker A second mechanical contact, which is connected to the other end of the semiconductor circuit breaker; an auxiliary semiconductor circuit breaker, which is connected in parallel to the second mechanical contact; a controller, which is respectively coupled to the semiconductor circuit breaker, The first mechanical contact, the second mechanical contact, and the auxiliary semiconductor circuit breaker, wherein when a ground fault occurs in the power system, the controller controls the semiconductor circuit breaker to open, and then controls the second The mechanical contact is opened, and the auxiliary semiconductor circuit breaker is controlled to be closed before the second mechanical contact is opened and opened after the second mechanical contact is opened, and then the first mechanical contact is controlled to be opened.

Further, when a short-circuit fault occurs in the power system, the controller controls the semiconductor circuit breaker to open, and then controls the first mechanical contact to open.

Further, the breaking current of the semiconductor circuit breaker is greater than the breaking current of the first mechanical contact and the breaking current of the second mechanical contact.

Further, the breaking current of the semiconductor circuit breaker is greater than the breaking current of the auxiliary semiconductor circuit breaker.

Further, the breaking current and the rated current of the auxiliary semiconductor circuit breaker are less than 10 amperes.

Further, the carrying current of the first mechanical contact and the carrying current of the second mechanical contact are respectively greater than the carrying current of the semiconductor circuit breaker.

The second aspect of the present invention provides a circuit breaking method, which is performed by the hybrid circuit breaker according to the first aspect of the present invention, wherein the circuit breaking method includes the following steps: when a ground fault occurs in the power system, controlling the circuit breaker The semiconductor circuit breaker is opened, and then the second mechanical contact is controlled to be opened, and the auxiliary semiconductor circuit breaker is controlled to be closed before the second mechanical contact is opened and opened after the second mechanical contact is opened , And then control the first mechanical contact to be disconnected.

Further, the circuit breaking method includes the following steps: when a short-circuit fault occurs in the power system, controlling the semiconductor circuit breaker to open, and then controlling the first mechanical contact to open.

A third aspect of the present invention provides a hybrid circuit breaker system, wherein the circuit breaker system includes the hybrid circuit breaker according to the first aspect of the invention, and the hybrid circuit breaker system includes: a processor; and a memory coupled with the processor, The memory has instructions stored therein. The instructions, when executed by the processor, cause the electronic device to perform actions. The actions include: controlling the semiconductor circuit breaker to open when a ground fault occurs in the power system, and then The second mechanical contact is controlled to be opened, and the auxiliary semiconductor circuit breaker is controlled to be closed before the second mechanical contact is opened and opened after the second mechanical contact is opened, and then the first mechanical contact is controlled The contact is broken.

Further, the action further includes: when a short-circuit fault occurs in the power system, controlling the semiconductor circuit breaker to open, and then controlling the first mechanical contact to open.

The hybrid circuit breaker provided by the present invention can be operated safely and has a lower cost. All switches in the hybrid circuit breaker provided by the present invention include mechanical contacts and semiconductor switches, and they are all operated within a safe operating range. The present invention does not require high current interruption requirements for the additional second mechanical contact, and there is no high rated current conduction requirement.

Description of the drawings

Figure 1 is a circuit connection diagram of the power system;

Figure 2 is a circuit connection diagram of a hybrid circuit breaker according to a specific embodiment of the present invention;

Fig. 3 is a switching sequence diagram of a hybrid circuit breaker under short-circuit fault and ground fault conditions respectively according to a specific embodiment of the present invention.

Detailed ways

The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

Figure 1 is a circuit connection diagram of a power system, which is particularly a DC power system. Wherein, the AC power supply S ₂ supplies power to two power supply branches B ₁ and B ₂ connected in parallel, and the power supply branches B ₁ and B ₂ respectively have an AC/DC converter (AC/DC converter). The specific power supply branches B ₁ and B ₂ are also connected in series with a protection device PD ₁ and PD _{2 respectively} . Among them, under the protection devices PD ₁ and PD ₂ are also a first parallel branch, a second parallel branch, and a third parallel branch. The parallel branch and the fourth parallel branch. The first parallel branch has a protection device PD ₁₁ , the second parallel road has a protection device PD ₁₂ , the third parallel branch has a protection device PD ₂₁ , and the fourth parallel road has a protection device PD ₂₂ . The DC power system also includes a battery source B ₃ and a photovoltaic power source B ₄ , wherein the battery source B ₃ and the photovoltaic power source B ₄ are also connected in series with protection devices PD ₃ and PD _{4, respectively} . Under the protection devices PD ₃ and PD ₄ , there are also a fifth parallel branch, a sixth parallel branch and a seventh parallel branch. Among them, the fifth parallel branch is connected in series with a protection device PD ₃₁ , the sixth parallel branch is connected in series with a protection device PD ₃₂ , and the seventh parallel branch is connected in series with a protection device PD ₄₁ . Exemplarily, the hybrid circuit breaker provided by the present invention can be applied to protection devices PD ₁ , PD ₂ , PD ₃ , PD ₄ , PD ₁₁ , PD ₁₂ , PD ₂₁ , PD ₂₂ , PD ₃₁ , PD ₃₂ , PD ₄₁ Either. It should be noted that the hybrid circuit breaker provided by the present invention can be applied to a DC power system and an AC power system.

Fig. 2 is a circuit connection diagram of a hybrid circuit breaker according to a specific embodiment of the present invention. As shown in FIG. 2, the hybrid circuit breaker 100 includes a first mechanical contact MC ₁ , a semiconductor circuit breaker MSS, an energy absorber AC, a second mechanical contact MC ₂ , an auxiliary semiconductor circuit breaker ASS and a controller. Wherein, the semiconductor circuit breaker MSS is connected to the first mechanical contact MC ₁ , the energy absorber AC is connected in parallel to the semiconductor circuit breaker ASS, and the second mechanical contact MC _{2 is} connected to the other end of the semiconductor circuit breaker MSS, The auxiliary semiconductor circuit breaker ASS is connected in parallel to the second mechanical contact MC ₂ . The controller is respectively coupled to the semiconductor circuit breaker MSS, the first mechanical contact MC ₁ , the second mechanical contact MC ₂ and the auxiliary semiconductor circuit breaker ASS, wherein, as shown in FIG. 2, the The semiconductor circuit breaker MSS is _{driven and switched by a first control signal C 1} , the first mechanical contact MC ₁ is driven by a fourth control signal C ₄ to switch, and the second mechanical contact MC ₂ is driven by a second control signal C ₂ For switching, the auxiliary semiconductor circuit breaker ASS is _{driven by the third control signal C 3} to switch.

The power system includes two types of faults, one is a short-circuit fault, and the other is a ground fault.

Specifically, when the short-circuit fault of the power system, the controller transmits a first control signal C ₁ MSS OFF controlling the semiconductor circuit-breaker, C ₄ and the fourth control signal controlling the first mechanical contact MC ₁ disconnect.

Specifically, when a ground fault occurs in the power system, the controller sends a first control signal C _{1 to} control the semiconductor circuit breaker MSS to open, and then sends a second control signal C _{2 to} control the second mechanical contact MC _{2 to open.} open, and transmits the third control signal C ₃ to control the auxiliary semiconductor ASS breaker is closed before the second mechanical contact and MC ₂ is disconnected after the second mechanical contact MC ₂ Off Off, then the first transmission The four control signal C ₄ controls the opening of the first mechanical contact MC ₁ .

Among them, the hybrid circuit breaker 100 also includes a plurality of semiconductor integrated circuit MOSFET chips to achieve the rated current of the circuit breaker, the order of magnitude is about several thousand to several ten thousand amperes, and the capacitance of its energy absorber may be very large, such as an RC snubber circuit. . The second mechanical contact MC _{2 is} used for isolation. The second mechanical contact MC ₂ is a fast mechanical circuit breaker, which is also used for isolation, and the semiconductor circuit breaker ASS is connected in parallel to the second mechanical contact MC ₂ . The semiconductor circuit breaker ASS is a MOSFET or an IGBT, which can carry several amperes.

Wherein, the semiconductor circuit breaker MSS, the first mechanical contact MC ₁ and the second mechanical contact MC ₂ are serial, and they work in different sequences according to different states and conditions. FIG 3 respectively show a timing chart of each switch 100 in the short-circuit fault and a ground fault circuit breaker mixing conditions, wherein the mixing timing chart showing the circuit breaker _{100. 1} S switch timing chart when the short circuit fault, S ₂ represents a timing chart showing mixing The switching sequence diagram of the circuit breaker 100 at the time of a ground fault.

Specifically, in a normal state, the semiconductor circuit breaker MSS, the first mechanical contact MC ₁ and the second mechanical contact MC ₂ are driven to switch by their control signals. In a normal state, the semiconductor circuit breaker MSS is in a closed state, the first mechanical contact MC ₁ is in a closed state, the auxiliary semiconductor circuit breaker ASS is in an open state, and the second mechanical contact MC ₂ is in a closed state.

When a short circuit fault occurs, the present invention can be identified by detecting the current flowing through the bus bars. Specifically, the controller first controls the semiconductor circuit breaker MSS to _{switch from closed to open at the first time t 11} through the first control signal C ₁ , and the current will be dominated by the capacitor of the semiconductor circuit breaker MSS and its energy absorber AC. Limit live. Then, after a first predetermined time, when the induced current is below the switching current value range of the _{first mechanical contact MC 1} _{, the controller controls the fourth control signal C 4} to drive at the second time t _{12 to} switch from closed For disconnection. Wherein, the first predetermined time is: Δt ₁ =t ₁₂ -t ₁₁ .

When a ground fault occurs, first, the controller uses the first control signal C ₁ to control the semiconductor circuit breaker MSS to _{switch from closed to open at the first time t 21} , and the current will be controlled by the semiconductor circuit breaker MSS. The capacitor and its energy absorber AC are mainly limited. Then, after a second predetermined time, when the induced current of the auxiliary semiconductor circuit breaker ASS is below the conduction capacity (usually a few amperes at most), the auxiliary semiconductor circuit breaker ASS is driven by the third control signal C3. The second time t21 is switched from open to closed. Wherein, the second predetermined time is: Δt ₂ =t ₂₂ -t ₂₁ . Then, the second mechanical contact MC ₂ is driven by the second control signal C _{2 to} switch from closed to open at the third time t23, so its current can be transmitted with the auxiliary semiconductor circuit breaker ASS. Wherein, after the second mechanical contact MC ₂ is completely switched by the second control signal C ₂ , the auxiliary semiconductor circuit breaker ASS is driven by the third control signal C 3 to switch from closed to open _{at the fourth time t 24} . Thereafter, the current will be mainly limited by the smaller capacitance of the auxiliary semiconductor circuit breaker ASS, and the capacitance of the auxiliary semiconductor circuit breaker ASS is probably less than 100 pF. Finally, the first mechanical contact MC ₁ is driven by the fourth control signal C _{4 to} switch from closed to open at the fifth time t _25.

That is, the first mechanical contact switch MC ₁ acts as a spacer, which have not only the insulation breaking breaking capacity. Semiconductor circuit breaker MSS is the main part. Both the semiconductor circuit breaker MSS and its energy absorber AC have parasitic capacitance. Therefore, even if the semiconductor circuit breaker MSS is turned off in the prior art, high-frequency current will still pass through the semiconductor circuit breaker MSS. Its energy absorber is AC transmission, and the radiation is very large, so it cannot play a shut-off effect in the end. The radiation value can reach the order of 4 amperes. The current of this order of magnitude makes the first mechanical contact MC ₁ unable to break normally, so the service life is affected, and even the switch contacts are damaged.

The present invention can solve the above problems by adding a second mechanical contact MC ₂ and an auxiliary semiconductor circuit breaker ASS, and sending a control signal through the controller to control the response of all the above elements in different states. Among them, the auxiliary semiconductor circuit breaker ASS is a small hybrid circuit breaker, which has no power requirements and low rated current requirements. Therefore, for different fault types, different control strategies are used for protection. The ground fault of the hybrid circuit breaker is caused by the high-frequency residual current. At the same time, the short-circuit protection function of the hybrid circuit breaker needs to be taken into account. Since the first mechanical contact MC ₁ and its control signal have limited the main fault current to high frequency current, and it is ampere level, it is broken by the auxiliary semiconductor circuit breaker ASS.

Further, the semiconductor circuit breaker breaking current is greater than the first MSS mechanical contact points MC and _a breaking current of the second mechanical contact points _2. MC breaking current. Among them, the breaking current of the semiconductor circuit breaker is determined according to the actual application, and its value range can range from tens of amperes to several thousand amperes.

Further, the breaking current of the semiconductor circuit breaker MSS is greater than the breaking current of the auxiliary semiconductor circuit breaker ASS.

Further, the breaking current and the rated current of the auxiliary semiconductor circuit breaker ASS are less than 10 amperes.

Further, the carrying current of the first mechanical contact MC _{1 and} the carrying current of the second mechanical contact MC ₂ are respectively greater than the carrying current of the semiconductor circuit breaker MSS.

The second aspect of the present invention provides a circuit breaker method, which is executed in the aforementioned hybrid circuit breaker, wherein the circuit breaker method includes the following steps: when a ground fault occurs in the power system, controlling the semiconductor circuit breaker to break Then control the second mechanical contact to open, and control the auxiliary semiconductor circuit breaker to close before the second mechanical contact is opened and open after the second mechanical contact is opened, and then control the The first mechanical contact is broken.

A third aspect of the present invention provides a hybrid circuit breaker system, wherein the circuit breaker system includes the aforementioned hybrid circuit breaker, and the hybrid circuit breaker system includes:

Processor; and

A memory coupled with the processor, the memory having instructions stored therein, the instructions, when executed by the processor, cause the electronic device to perform actions, and the actions include:

When a ground fault occurs in the power system, the semiconductor circuit breaker is controlled to open, then the second mechanical contact is controlled to open, and the auxiliary semiconductor circuit breaker is controlled to close before the second mechanical contact is opened. After the second mechanical contact is disconnected, it is disconnected, and then the first mechanical contact is controlled to be disconnected.

In order to verify the present invention, we established a hybrid circuit breaker model and simulated a serious ground fault RGF=1Ω@0.295s, and combined the semiconductor circuit breaker MSS, the auxiliary semiconductor circuit breaker ASS, and the first mechanical circuit breaker The switching time between the contact MC ₁ and the second mechanical contact MC ₂ _{is set as: t 21} =0.3s; t ₂₂ =0.301s; t ₂₂ =0.302s; t ₂₃ =0.3012s; t ₂₅ =0.3022s. The verification result is that the semiconductor circuit breaker MSS, the auxiliary semiconductor circuit breaker ASS, the first mechanical contact MC ₁ and the second mechanical contact MC ₂ will all switch in their safe execution area. In addition, the cost of the present invention is lower, and the auxiliary semiconductor circuit breaker does not have a high-current interruption requirement, nor does it have a high-rated current conduction requirement.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as limiting the present invention. After those skilled in the art have read the above content, various modifications and substitutions to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims. In addition, any reference signs in the claims should not be regarded as limiting the involved claims; the word "comprising" does not exclude other claims or devices or steps not listed in the specification; "first", "section Words such as "two" are only used to indicate names, and do not indicate any specific order.

Claims

Hybrid circuit breakers, including:

A first mechanical contact;

A semiconductor circuit breaker connected to the first mechanical contact;

An energy absorber connected in parallel to the semiconductor circuit breaker;

A second mechanical contact, which is connected to the other end of the semiconductor circuit breaker;

An auxiliary semiconductor circuit breaker connected in parallel to the second mechanical contact;

A controller coupled to the semiconductor circuit breaker, the first mechanical contact, the second mechanical contact and the auxiliary semiconductor circuit breaker,

Wherein, when a ground fault occurs in the power system, the controller controls the semiconductor circuit breaker to open, then controls the second mechanical contact to open, and controls the auxiliary semiconductor circuit breaker to open the second mechanical contact. It is closed before opening and opened after the second mechanical contact is opened, and then the first mechanical contact is controlled to be opened.
The hybrid circuit breaker according to claim 1, wherein when a short-circuit fault occurs in the power system, the controller controls the semiconductor circuit breaker to open, and then controls the first mechanical contact to open.
The hybrid circuit breaker according to claim 1, wherein the breaking current of the semiconductor circuit breaker is greater than the breaking current of the first mechanical contact and the breaking current of the second mechanical contact.
The hybrid circuit breaker according to claim 1, wherein the breaking current of the semiconductor circuit breaker is greater than the breaking current of the auxiliary semiconductor circuit breaker.
The hybrid circuit breaker according to claim 1, wherein the breaking current and the rated current of the auxiliary semiconductor circuit breaker are less than 10 amperes.
The hybrid circuit breaker according to claim 1, wherein the carrying current of the first mechanical contact and the carrying current of the second mechanical contact are respectively greater than the carrying current of the semiconductor circuit breaker.
The circuit breaking method is performed by the hybrid circuit breaker according to any one of claims 1 to 6, wherein the circuit breaking method comprises the following steps: when a ground fault occurs in the power system, controlling the semiconductor circuit breaker The second mechanical contact is opened, and the auxiliary semiconductor circuit breaker is controlled to be closed before the second mechanical contact is opened and opened after the second mechanical contact is opened, and then controlled The first mechanical contact is broken.
The hybrid method according to claim 7, wherein the circuit breaking method comprises the following steps: when a short circuit fault occurs in the power system, controlling the semiconductor circuit breaker to open, and then controlling the first mechanical contact disconnect.
A hybrid circuit breaker system, wherein the circuit breaker system includes the hybrid circuit breaker according to any one of claims 1 to 6, and the hybrid circuit breaker system includes:

Processor; and

A memory coupled with the processor, the memory having instructions stored therein, the instructions, when executed by the processor, cause the electronic device to perform actions, and the actions include:

When a ground fault occurs in the power system, the semiconductor circuit breaker is controlled to open, then the second mechanical contact is controlled to open, and the auxiliary semiconductor circuit breaker is controlled to close before the second mechanical contact is opened. After the second mechanical contact is disconnected, it is disconnected, and then the first mechanical contact is controlled to be disconnected.
The hybrid circuit breaker system according to claim 9, wherein the action further comprises: when a short-circuit fault occurs in the power system, controlling the semiconductor circuit breaker to open, and then controlling the first mechanical contact to open .