CN113299504B - A magnetron oscillating DC circuit breaker with multi-media fractures connected in series - Google Patents

Abstract

A magnetron oscillating DC circuit breaker connected in series with multi-media fractures is composed of a main current branch, an oscillation transfer branch, an overvoltage limiting branch and an auxiliary magnetic field arc blowing component. The main current loop, the oscillation transfer branch and the overvoltage limiting branch are connected in parallel, and the auxiliary magnetic field arc blowing component provides the magnetic field. Among them: the gas fracture and the vacuum fracture are equipped with high-speed mechanical switches, which are connected in series to form the main current branch, the oscillating capacitor forms the oscillation transfer branch, and the arrester forms the overvoltage limiting branch. The magnetic field is provided by the magnetic arc blowing component to force the voltage of the gas fracture and the vacuum fracture to increase, and the arcs of the two fractures oscillate together, forming a circuit oscillation with the characteristic frequency of the oscillation transfer branch, forcing the main circuit current to cross zero to complete the breaking. The DC circuit breaker has bidirectional breaking capability and low cost, and can be applied to a DC power supply system.

Description

A magnetron oscillating DC circuit breaker with multi-media fractures connected in series

technical field

The invention relates to a magnetron oscillation type DC circuit breaker connected in series with multi-medium fractures, which has bidirectional current breaking capability.

Background technique

In recent years, with the continuous development of DC transmission and distribution technology, DC transmission and distribution has become one of the mainstream directions of power system development. The DC circuit breaker is an important control device in the DC transmission and distribution system. It is used to control the input or withdrawal of power lines or equipment, and to protect the normal operation of line equipment. Because the DC grid has problems such as rapid short-circuit current rise, high peak value, and no natural zero-crossing point, the design of DC circuit breakers is more difficult than AC circuit breakers.

Current technical solutions for DC circuit breakers include mechanical circuit breakers, solid state circuit breakers and hybrid circuit breakers. The original mechanical or hybrid type requires pre-charged capacitors or power electronics, which is costly, bulky, and difficult to apply on a large scale.

SUMMARY OF THE INVENTION

In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a vacuum DC circuit breaker with a series of gas fractures, which can increase the voltage of the main branch fracture by using a vacuum high-speed mechanical switch and a gas fracture to open the arc, and use the gas medium fracture to blow the arc. The high arc voltage assists the arc blowing at the vacuum fracture, forming a magnetron oscillation and increasing the capacitor oscillation voltage during the oscillation process, forcing the main circuit current oscillation to cross zero, thereby realizing rapid breaking. The solution of the invention is based on the self-excited oscillation breaking, and has the advantages of low cost, small size and high reliability, and is favorable for large-scale popularization and application. The main loop current can be transferred to the oscillation transfer branch by matching the appropriate oscillation transfer branch parameters.

Specifically, the present invention adopts the following technical solutions:

The utility model relates to a vacuum DC circuit breaker with gas fractures connected in series, which is composed of a main current circuit, an oscillation transfer branch, an overvoltage limiting branch and an auxiliary magnetic field arc blowing component. The main current loop, the oscillation transfer branch and the overvoltage limiting branch are connected in parallel, and then lead out through the outlet terminals A1 and A2. It is characterized by:

(1) The main current loop is composed of a vacuum fracture S1 and a gas fracture S2, which are respectively provided with a vacuum mechanical high-speed switch and a gas mechanical high-speed switch.

(2) The oscillation transfer branch is composed of matched oscillation capacitors C1.

(3) The overvoltage limiting branch is composed of a surge arrester MOV.

When the system is in a normal flow-through state, the system current flows through the main circuit. At this time, the two fractures S1 and S2 of the main circuit are closed, and there is no voltage on the capacitor C1 of the oscillation transfer branch; the auxiliary magnetic field arc blowing component is not triggered, and no magnetic field is generated; the voltage across the overvoltage limiting branch does not reach the conduction threshold, No current flows.

When a short-circuit fault occurs or the system receives an opening command from the superior control system, the control system sends an opening command, the control system sends an opening action command to the main circuit high-speed mechanical switches S1 and S2, and triggers the auxiliary magnetic field arc blowing component to start . The magnetic field arc blowing component generates a magnetic field and acts on the high-speed mechanical switch of the main circuit. The arc burns in the gas fracture and the vacuum fracture. The vacuum arc and the gas arc are affected by the transverse magnetic field generated by the magnetic field arc blowing component. Frequency oscillation occurs together, and the current is transferred to On the oscillation transfer branch capacitor C1, the main loop current oscillates to zero and charges the transfer branch capacitor. After the oscillation capacitor C1 is charged up to the conduction threshold of the overvoltage limiting branch, the current transfers from the oscillation transfer branch to the overvoltage. Limit the branch circuit, discharge through the voltage limiting branch circuit, and complete the opening of the circuit breaker.

The main circuit fracture of the circuit breaker is characterized in that: the fractures S1 and S2 are provided with high-speed mechanical switches, including but not limited to high-speed mechanical switches based on electromagnetic repulsion, mechanical switches driven by high-speed motors or high-speed mechanical switches based on permanent magnet repulsion. Mechanical switch. The one on the fracture S1 is the vacuum mechanical switch, and the one on the fracture S2 is the gas mechanical switch.

The magnetic field arc blowing assembly of the circuit breaker is characterized in that: the fractures S1 and S2 are provided with magnetic field arc blowing assemblies, including but not limited to one or more combinations of the following: electromagnets, electromagnetic coils, and permanent magnets.

Another feature of the magnetic arc blowing component of the circuit breaker is that the magnetic fields provided by the component for the fractures S1 and S2 can be the following types: transverse magnetic field in a single direction, superimposed transverse magnetic field in multiple directions, and rotating transverse magnetic field.

The oscillation capacitor of the circuit breaker is characterized in that: the oscillation transfer branch oscillation capacitor C1 is a single capacitor, a series-parallel capacitor group, a single capacitor series inductance, and a series-parallel capacitor group series inductance.

The gas filling of the high-speed mechanical switch of the circuit breaker is characterized in that: the filling gas in the high-speed mechanical switch of the filling gas includes but is not limited to one or more mixtures of the following gases: air, compressed air, nitrogen, hydrogen, SF6 gas, inert gas.

Description of drawings

The accompanying drawings are for the purpose of illustrating preferred embodiments only and are not to be considered limiting of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative efforts. Also, the same components are denoted by the same reference numerals throughout the drawings.

Figure 1 is a schematic diagram of the structure of the circuit breaker body;

Fig. 2 is the circuit breaker breaking principle diagram of the present invention;

3(a) to 3(d) are schematic diagrams of the structure of the circuit breaker of the present invention during operation;

Fig. 4 is an example of the circuit breaker of the present invention, and the fractures are vacuum fracture and air fracture;

Fig. 5 is an example of the circuit breaker of the present invention, and the fractures are vacuum fractures and N gas fractures;

Fig. 6 is an example of the circuit breaker of the present invention, and the fractures are vacuum fractures and H gas fractures;

Fig. 7 is an example of the circuit breaker of the present invention, and the fractures are vacuum fractures and air fractures, which are respectively provided with independent oscillating capacitors;

Fig. 8 is an example of the circuit breaker of the present invention, and the fractures are vacuum fractures and air fractures, which are respectively provided with independent oscillation capacitors and independent MOVs;

Fig. 9 is a kind of structural schematic diagram of the interruption port and the magnetic field arc blowing assembly of the present invention;

Figures 10(a) to 10(c) are partial drive circuit topologies of the magnetic field arc blowing assembly in the present invention.

Detailed ways

Specific embodiments of the present disclosure will be described in more detail below with reference to FIGS. 1 to 10( c ) of the accompanying drawings. While specific embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be more thoroughly understood, and will fully convey the scope of the present disclosure to those skilled in the art.

It should be noted that certain terms are used in the description and claims to refer to specific components. It should be understood by those skilled in the art that the same component may be referred to by different nouns. The present specification and claims do not take the difference in terms as a way to distinguish components, but take the difference in function of the components as a criterion for distinguishing. As referred to throughout the specification and claims, "comprising" or "including" is an open-ended term and should be interpreted as "including but not limited to". Subsequent descriptions in the specification are preferred embodiments for implementing the present disclosure, however, the descriptions are for the purpose of general principles of the specification and are not intended to limit the scope of the present disclosure. The scope of protection of the present disclosure should be defined by the appended claims.

To facilitate the understanding of the embodiments of the present disclosure, the following will take specific embodiments as examples for further explanation and description in conjunction with the accompanying drawings, and each accompanying drawing does not constitute a limitation to the embodiments of the present disclosure.

Fig. 1 is a vacuum DC circuit breaker with gas fractures in series provided by the present invention, which is composed of a main current circuit, an oscillation transfer branch, an overvoltage limiting branch and an auxiliary magnetic field arc blowing circuit. The main current loop, the oscillation transfer branch and the overvoltage limiting branch are connected in parallel, and then lead out through the outlet terminals A1 and A2. The main current loop consists of a vacuum high-speed mechanical switch S1 and a gas-filled high-speed mechanical switch S2. The oscillation transfer branch is composed of a matched oscillation capacitor C1. The overvoltage limiting branch is composed of zinc oxide arrester MOVs in series and parallel.

Fig. 2 is the breaking principle diagram of the circuit breaker in the present invention. When the circuit breaker receives the opening command, the vacuum high-speed mechanical switch and the gas high-speed mechanical switch act to generate an arc, and at the same time, the auxiliary magnetic field arc blowing component acts to generate a magnetic field to force the vacuum arc voltage to change, and its characteristic frequency is f1; on the oscillation transfer branch The characteristic frequency f2 of the LC loop composed of the oscillating capacitor and the stray inductance in the line; when the two characteristic frequencies are close, the current oscillates between the main current loop and the oscillation transfer branch, which plays the role of current transfer and charging the oscillating capacitor. Effect.

Figures 3(a) to 3(d) of the circuit breaker described in this embodiment are a schematic structural diagram of the circuit breaker during operation.

As shown in FIG. 3( a ), when the system is in a normal flow-through state, the system current flows through the main circuit. At this time, the high-speed mechanical switches S1 and S2 of the main circuit are closed, and there is no voltage on the oscillation transfer branch capacitor C1; there is a certain precharge voltage on the auxiliary magnetic field arc blowing capacitor C2, and the power semiconductor device T1 on the magnetic field arc blowing circuit is not triggered. There is no current in the magnetic field arc blowing circuit; the voltage across the overvoltage limiting branch does not reach the conduction threshold, and no current flows.

As shown in Figure 3(b), when a short-circuit fault occurs or the system receives an opening command from the superior control system, the control system sends an opening command, and the control system sends an opening action command to the main circuit high-speed mechanical switches S1 and S2 , and trigger the semi-controlled power semiconductor device T1 of the auxiliary magnetic field blowing arc circuit.

As shown in Figure 3(c), the arc blowing circuit of the magnetic field discharges, and the arc on the high-speed mechanical switch of the main circuit burns in the vacuum chamber. Under the influence of the magnetic field of the arc blowing coil of the magnetic field, frequency oscillation occurs, and the current is transferred to the oscillation transfer branch. On the capacitor C1, the current of the main circuit oscillates to zero and charges the capacitor of the transfer branch.

As shown in Figure 3(d), after the oscillating capacitor C1 is charged up to the turn-on threshold of the overvoltage limiting branch, the current is transferred from the oscillation transfer branch to the overvoltage limiting branch, discharged through the voltage limiting branch, and the circuit is disconnected The device is disconnected.

Fig. 4 provides an example of the present invention, and the fracture is a vacuum fracture and an air fracture;

Fig. 5 provides an example of the present invention, and the fracture is a vacuum fracture and a N gas fracture;

Fig. 6 provides an example of the present invention, and the fracture is a vacuum fracture and a H gas fracture;

Fig. 7 provides an example of the present invention, and the fractures are vacuum fractures and air fractures, which are respectively provided with independent oscillating capacitors;

Fig. 8 provides an example of the present invention, and the fracture is a vacuum fracture and an air fracture, which are respectively provided with an independent oscillation capacitor and an independent MOV;

FIG. 9 shows the arrangement structure of a fracture and a magnetic field arc blowing assembly of the present invention;

Figures 10(a) to 10(c) show the partial drive circuit topology diagrams of the magnetic field arc blowing component of the present invention, including the capacitor matching the semiconductor component discharge circuit, the discharge circuit with diode freewheeling, and the constant current source discharge circuit ;

Although the embodiments of the present disclosure have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above-mentioned specific embodiments and application fields, and the above-mentioned specific embodiments are only illustrative, instructive, and not restrictive . Under the inspiration of this specification and without departing from the scope of protection of the claims of the present disclosure, those of ordinary skill in the art can also make many forms, which all belong to the protection of the present disclosure.

Claims (6)

1. A vacuum DC circuit breaker with gas fractures in series, consisting of a main current loop, an oscillation transfer branch, an overvoltage limit branch and an auxiliary magnetic field arc blowing component, wherein the main current loop, the oscillation transfer branch, and the overvoltage limit branch. After the circuits are connected in parallel, they are led out through the outlet terminals A1 and A2, which are characterized by: (1) The main current loop is composed of a vacuum fracture S1 and a gas fracture S2, which are respectively provided with a vacuum mechanical high-speed switch and a gas mechanical high-speed switch; (2) The oscillation transfer branch is composed of a matched oscillation capacitor C1; (3) The overvoltage limiting branch is composed of zinc oxide arrester MOV in series and parallel. When the system is in a normal current-flow state, the system current flows through the main current loop. At this time, the two fractures S1 and S2 of the main current loop are closed, and there is no voltage on the oscillating capacitor C1; the auxiliary magnetic field arc blowing component is not triggered, and there is no magnetic field. Generated; the voltage across the overvoltage limiting branch does not reach the turn-on threshold, and no current flows; When a short-circuit fault occurs or the system receives an opening command from the superior control system, the control system sends an opening command, and the control system sends an opening action command to the vacuum mechanical high-speed switch and gas mechanical high-speed switch of the main current circuit, and triggers the auxiliary magnetic field The arc blowing component starts, and the auxiliary magnetic field arc blowing component generates a magnetic field that acts on the vacuum mechanical high-speed switch and gas mechanical high-speed switch of the main current circuit. The arc burns in the gas fracture and vacuum fracture, and the vacuum arc and gas arc are generated by the auxiliary magnetic field arc blowing component. Influenced by the transverse magnetic field, frequency oscillation occurs together, and the current is transferred to the oscillation capacitor C1. The current in the main current loop oscillates to zero and charges the oscillation capacitor. After the oscillation capacitor C1 is charged up to the conduction threshold of the overvoltage limiting branch, The current is transferred from the oscillation transfer branch to the overvoltage limiting branch, and the circuit breaker completes the opening through the overvoltage limiting branch. When the circuit breaker receives the opening command, the vacuum mechanical high-speed switch and the gas mechanical high-speed switch act together. The arc is generated, and the auxiliary magnetic field blows the arc component to act, and the magnetic field forces the vacuum arc voltage to change, and its characteristic frequency is f1; the LC loop characteristic frequency f2 composed of the oscillating capacitance on the oscillation transfer branch and the stray inductance in the oscillation transfer branch line ; When the two characteristic frequencies are close, the current oscillates between the main current loop and the oscillation transfer branch, which has the effect of current transfer and charging of the oscillation capacitor. 2. The circuit breaker according to claim 1, characterized in that: the mechanical high-speed switches provided by the fractures S1 and S2 include a mechanical high-speed switch based on electromagnetic repulsion, a mechanical high-speed switch driven by a high-speed motor or a permanent-magnet-based high-speed switch. For the mechanical high-speed switch of repulsion force, the vacuum mechanical high-speed switch on the interruption port S1, and the gas mechanical high-speed switch on the fracture port S2. 3. The circuit breaker according to claim 1, characterized in that: said fractures S1 and S2 are provided with auxiliary magnetic field arc blowing components, comprising one or more of the following combinations: electromagnet, electromagnetic coil, permanent magnet . 4. The circuit breaker according to claim 3 is characterized in that: the magnetic fields provided by the auxiliary magnetic field arc blowing assembly for the fractures S1 and S2 are the following types: transverse magnetic field in a single direction, superimposed transverse magnetic field in multiple directions, rotating the transverse magnetic field. 5. The circuit breaker according to claim 1, wherein the oscillation transfer branch oscillation capacitor C1 is a single capacitor, a series-parallel capacitor group, a single capacitor series inductance, or a series-parallel capacitor group series inductance. 6. The circuit breaker according to any one of claims 1-5, wherein the filling gas in the gas-mechanical high-speed switch comprises one or more mixtures of the following gases: air, compressed air, nitrogen, Hydrogen, SF6 gas, inert gas.

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