CN103151189B - Electromagnetic-repuhigh-speeden high-speeden piston type interrupter - Google Patents

Abstract

The invention relates to a breaker for fast current-limiting breaking when a short-circuit fault occurs in a power grid, in particular to a piston-type high-speed breaker driven by electromagnetic repulsion. It includes a repulsion drive circuit, a repulsion coil connected in the repulsion drive circuit, an input terminal and an output terminal, a bridge is connected between the input terminal and the output terminal, and the bridge body is covered with an insulating sleeve. A repulsion disk is provided, and the repulsion disk is located above the repulsion coil, and an insulating block capable of breaking the bridge body is fixed on the repulsion disk. The invention adopts the electromagnetic repulsion driving technology to replace the explosive driving technology, overcomes the deficiency of the explosive driving technology, and uses the structure connecting the bridge body between the two terminals as a current-through circuit, which not only meets the temperature rise requirement for large current flow , It also reduces the energy required to break the breaker, greatly reduces the cost, improves the breaking speed and reliability, and has broad engineering application prospects and good economic benefits. <!--1-->

Description

Electromagnetic repulsion drives piston type high-speed breaker

technical field

The invention relates to a breaker for fast current-limiting breaking when a short-circuit fault occurs in a power grid, in particular to a piston-type high-speed breaker driven by electromagnetic repulsion.

Background technique

With the increasing level of short-circuit current in the power grid, the peak value of short-circuit current can reach more than 100kA, and the rising rate of short-circuit current di/dt is extremely high. The limit breaking capacity of traditional circuit breakers is insufficient, and the operating time is long, so it is difficult to meet short-circuit faults. Requirements for fast current-limiting breaking. Installing a new fault current limiting device (FCL) in the power grid is an ideal solution to this kind of problem. Research on new current limiting devices with various principles has been carried out at home and abroad, such as superconducting current limiter, solid state current limiter, Liquid metal current limiter, current limiting circuit breaker, current limiting fuse, etc. The current-limiting fuse is a high-speed current-limiting protection device that combines explosive breaking technology with fast-acting fuse technology, and it is also one of the most widely used current-limiting protection technologies in commercial use so far. According to the working principle, current-limiting fuses can be divided into electronic measurement and control current-limiting fuses and arc-triggered current-limiting fuses.

The electronic measurement and control current-limiting fuse is composed of an electronic detection trigger device, an explosive breaker and a fast fuse connected in parallel with it. At present, representative products of electronic measurement and control current-limiting fuses include ABB's Is-limiter, Ferraz's Pyristor, G&W's Clip, etc. The principle of the detection trigger device is to detect the amplitude or change of the line current through the current sensor When the rate exceeds the set value, the electronic control unit sends a signal to detonate the explosive in the breaker to complete the breaking. The rated voltage of this type of product can reach 40.5kV, the rated current can reach 5kA, and the breaking current can reach more than 200kA. It has been widely used at home and abroad. However, because the device uses sensors and electronic circuits for fault detection, there are problems such as electromagnetic interference or component failures that cause malfunction or refusal in practical applications.

The arc-triggered current-limiting fuse uses an arc trigger to replace the electronic sensor and control unit, and directly uses the thermal effect of the short-circuit current as a short-circuit detection method and trigger condition. When a short circuit occurs, the melt in the arc trigger is fused under the action of the short circuit current to generate an arc, and the arc voltage is used to ignite the explosive in the explosive breaker and complete the breaking, which overcomes the low reliability of the electronic measurement and control type current-limiting fuse detection trigger device , The need for external power supply and other shortcomings.

However, whether it is an electronic measurement and control current-limiting fuse or an arc-triggered current-limiting fuse, their high-speed breakers are driven by the impact force generated by the explosive explosion, so that the breaker can be quickly broken and the current is transferred to on the arc-extinguishing fuse. The limitations of using explosives to drive are: ①The life of explosives is limited, and will gradually decompose and fail with the increase of use time; ②Explosives and other pyrotechnic products are expensive, and need to be replaced after each action, which is economical; ③Requirements for ambient temperature Harsh; ④The noise is loud when the short circuit is broken, and sparks will be generated when it explodes. When used in some special occasions with flammable gases, a closed box is required, and the overall volume is large. Therefore, other new fast actuation methods that can replace explosive actuated breakers need to be considered.

Contents of the invention

The object of the present invention is to solve the shortcomings of the above-mentioned background technology, and provide an electromagnetic repulsion-driven piston-type high-speed breaker with fast breaking speed and high reliability that can replace the explosive-driven technology.

The technical solution adopted in the present invention is: an electromagnetic repulsion-driven piston-type high-speed breaker, including a repulsion drive circuit, a repulsion coil connected in the repulsion drive circuit, an input terminal and an output terminal, an input terminal and an output terminal A bridge body is bridged between them, and an insulating sleeve is provided over the bridge body. A repulsion disk is arranged under the bridge body. The repulsion disk is located above the repulsion coil, and an insulating block capable of breaking the bridge body is fixed on the repulsion disk.

Further, the repulsion drive circuit includes a capacitor, a thyristor and a freewheeling diode connected in series, the anode and cathode of the capacitor are respectively connected to the negative pole of the freewheeling diode and the cathode of the thyristor, and the positive pole of the freewheeling diode is connected to the anode of the thyristor , the repulsion coil is connected in series between the capacitor and the thyristor and connected in parallel with the freewheeling diode. The repulsion drive circuit provides a large pulse current to the repulsion coil by controlling the conduction of the thyristor. When the pulse current flows through the repulsion coil, a magnetic field is generated on it and acts on the repulsion disk.

Further, the bridge body includes a central copper block and connecting blocks at the upper and lower ends, the material of the connecting block is metal, the edges of the upper and lower ends of the central copper block are respectively connected with the connecting blocks at the upper and lower ends, and the connecting blocks at the upper and lower ends are respectively connected to the input The connection terminal is connected to the output connection terminal; a square or circular hole is opened in the center of the connection block; the central copper block is a rectangular parallelepiped or cylindrical structure, matching with the square or circular hole opened in the center of the connection block.

Further, the bridge body includes a central copper block and connecting blocks at the upper and lower ends, the material of the connecting block is metal, and a tapered hole is opened in the center of the connecting block; the central copper block is a cone structure, and the upper and lower ends of the central copper block are respectively embedded In the tapered holes of the connecting blocks at the upper and lower ends, the connecting blocks at the upper and lower ends are respectively connected with the input terminal and the output terminal.

Further, the insulating sleeve is made of epoxy resin or other insulating materials; the upper and lower ends of the insulating sleeve are respectively connected to the input terminal and the output terminal, so as to realize the isolation between the bridge body and the external environment.

Further, the repulsion disk is an aluminum disk or a copper disk used to induce the magnetic field generated by the repulsion coil and generate electromagnetic repulsion to drive the insulating block to hit and break the bridge body.

Furthermore, the upper end of the insulating block made of insulating material passes through the input terminal and extends below the bridge body.

The invention adopts the electromagnetic repulsion driving technology to replace the explosive driving technology, overcomes the deficiency of the explosive driving technology, and uses the structure connecting the bridge body between the two terminals as a current-through circuit, which not only meets the temperature rise requirement for large current flow , It also reduces the energy required to break the breaker, greatly reduces the cost, improves the breaking speed and reliability, and has broad engineering application prospects and good economic benefits.

Description of drawings

Fig. 1 is the circuit schematic diagram of the present invention.

Fig. 2 is a longitudinal sectional view of a bridge body of the present invention.

Fig. 3 is a longitudinal sectional view of another bridge body of the present invention.

Fig. 4 is a schematic diagram of the first solution of the present invention applied to a hybrid current-limiting fuse.

FIG. 5 is a schematic diagram of voltage and current during the breaking process of the hybrid current-limiting fuse of the first solution in FIG. 4 .

Fig. 6 is a diagram of a second solution of the present invention applied to a hybrid current-limiting fuse.

FIG. 7 is a schematic diagram of voltage and current during the breaking process of the hybrid current-limiting fuse of the second solution in FIG. 6 .

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but they do not limit the present invention.

As shown in Fig. 1, the present invention includes a repulsion drive circuit and a repulsion coil L ₀ connected in the repulsion drive circuit. The repulsion driving circuit includes a capacitor C ₀ , a thyristor F ₀ and a freewheeling diode _D0 connected in series with a pre-charged voltage. The positive pole and negative pole of the capacitor _{C0 are respectively connected to the negative pole of the freewheeling diode D0 and} the negative pole of the thyristor _F0 . Continued The anode of the current diode D ₀ is connected to the anode of the thyristor F ₀ , the repulsive coil is connected in series between the capacitor C ₀ and the thyristor F ₀ and connected in parallel with the freewheeling diode D ₀ , and the thyristor F ₀ is turned on after receiving the trigger signal Rt from the external circuit. The present invention also includes an input connection terminal 1 and an output connection terminal 2, and a bridge is connected between the input connection terminal 1 and the output connection terminal 2. An insulating sleeve 5 is tightly wrapped around the outside of the bridge, and the material of the insulating sleeve 5 is epoxy resin or other insulating materials; the upper and lower ends of the insulating sleeve 5 are respectively connected to the input terminal 1 and the output terminal 2 to realize the connection between the bridge body and the outside. isolation between environments. A repulsion disk 6 is arranged below the bridge body, and the repulsion disk 6 is an aluminum disk or a copper disk. The repulsion disk 6 is located above the repulsion coil _L0 , and is used to induce the magnetic field generated by the repulsion coil _L0 and generate electromagnetic repulsion to drive the insulating block 7 to break the bridge. body. An insulating block 7 that can separate the upper and lower ends of the bridge body is fixed on the repulsion plate 6. The insulating block 7 is made of insulating material. The upper end of the insulating block 7 passes through the input terminal 1 and extends below the central copper block 4 of the bridge body. .

As shown in Figure 2, the bridge body includes a central copper block 4 and connecting blocks 3 at the upper and lower ends; the edges at the upper and lower ends of the central copper block 4 are respectively connected with the connecting blocks 3 at the upper and lower ends, and the connecting blocks 3 at the upper and lower ends are respectively connected by bolts. It is connected with the input terminal 1 and the output terminal 2 to realize normal circulation and break the circuit. The connecting block 3 is made of metal, with a square or circular hole in the center; the central copper block 4 is a cuboid or cylindrical structure, which matches the square or circular hole provided in the center of the connecting block 3 .

The connection block 3 and the central copper block 4 of the bridge body in Fig. 2 have an integral structure. Now design another bridge body, as shown in Figure 3, the connection block 3 of the bridge body is separated from the central copper block 4, a tapered hole is opened in the center of the connection block 3, and the central copper block 4 is designed as a cone embedded in the connection block 3 In the tapered hole, the diameter of the upper end of the central copper block 4 is greater than the diameter of the lower end, and the central copper block 4 is blocked by the tapered hole provided by the lower end connecting block. The insulating block 7 is forced to move upward against the central copper block 4, so that the bridge body is disconnected

The working principle of the present invention is as follows:

When a short circuit occurs, the thyristor F0 in the repulsion driving circuit receives the action trigger signal Rt and turns on, the pre-charged capacitor _C0 starts to discharge to the repulsion coil _L0 and generates a current, and the current forms a magnetic field in the _repulsion coil _L0 , the magnetic field acts on the upper repulsion plate 5 to generate electromagnetic repulsion, and the repulsion plate 5 drives the insulating block 7 after a certain action delay time, and then hits upwards to break the bridge body in the breaker to realize the input terminal 1 and output terminal 2 Interruption of circuits.

As shown in Figure 4, it is the first scheme for the application of the electromagnetic repulsion-driven piston-type high-speed breaker in the hybrid current-limiting fuse of the present invention: the arc trigger is placed between the electromagnetic repulsion-driven piston-type high-speed breaker and the extinguisher In addition to the parallel branch of the arc fuse, the device is referred to as the external solution of the arc trigger.

As shown in FIG. 5 , it is a schematic diagram of current and voltage during the breaking process of the hybrid current-limiting fuse in the solution of external arc trigger in FIG. 4 .

The working principle of the external application scheme of the arc trigger is as follows:

During normal operation, the current i passes through the arc trigger 8, and mainly flows through the piston type high-speed breaker driven by electromagnetic repulsion, that is, the current i ₁ , and a small amount of current i ₂ flows through the arc extinguishing fuse 10. When a short circuit occurs, the melt in the arc trigger 8 is fused and starts arcing, the voltage u at both ends of the arc extinguishing fuse 10 becomes the arc voltage U ₁ , and the pulse transformer 9 connected in parallel at both ends of the arc trigger 8 is directed to the repulsive force driving circuit. The thyristor F ₀ sends a trigger signal Rt, the pre-charged capacitor C ₀ discharges to the repulsion coil L ₀ and generates a current, the current forms a magnetic field in the repulsion coil L ₀ , the magnetic field acts on the upper repulsion disk 6 to generate electromagnetic repulsion, and the repulsion disk 6 Drive the insulating block 7 to break the bridge in the breaker upward after a certain action delay time t _a , at this time, the voltage u at both ends of the arc-extinguishing fuse 8 becomes the arc voltage U ₂ , and the current i ₁ flows from the breaker to The arc-extinguishing fuse 10 is transferred, and after the commutation time _tc , the current i1 is completely transferred to the arc _- extinguishing fuse 10. After that, the arc-extinguishing fuse 10 is blown and arced after a period of time _tz , and the arc-extinguishing fuse 10 appears at both ends of the arc-extinguishing fuse 10. Overvoltage, the short-circuit current begins to drop, and finally the circuit is completely broken, and the voltage u at both ends of the arc-extinguishing fuse 10 becomes a constant voltage _Ue . t _z is the dielectric recovery time after the breaker current i ₁ crosses zero. If the dielectric in the breaker has recovered its insulation, it can withstand the overvoltage, otherwise the breaker will be broken down again by the overvoltage, which will affect the current limiting effect.

After a short circuit occurs, from the moment t ₀ of the arc trigger 8 fusing, after the action time t _a of the insulating block 7, that is, from the moment t ₁ when the bridge body of the breaker is interrupted, the current i ₁ flows from the breaker Transfer to the arc-extinguishing fuse current i ₂ breaker, after the commutation time t _c , that is, the current i ₁ is completely transferred to the arc-extinguishing fuse at time t ₂ , and the current reaches the peak value and starts at the arc-extinguishing fuse time t ₃ Decline, until the circuit breaking time t ₄ current i ₂ drops to zero.

As shown in Figure 6, it is the second scheme for the application of the electromagnetic repulsion-driven piston-type high-speed breaker in the hybrid current-limiting fuse of the present invention: after the arc trigger and the electromagnetic repulsion-driven piston-type high-speed breaker are connected in series, Then connect it in parallel with the arc-extinguishing fuse. Further analysis of the scheme in Figure 3 shows that there is an arcing process in the process of commutating the current to the arc-extinguishing fuse of the piston-type high-speed breaker driven by electromagnetic repulsion, and the recovery of the medium after the current crosses zero is affected by the breaker. The effect of commutation arc energy. Therefore, this patent provides an improved solution that can reduce the arcing energy of the breaker. Compared with the external solution of the arc trigger in Figure 3, this improved solution is also called the built-in solution of the arc trigger.

As shown in FIG. 7 , it is a schematic diagram of current and voltage in the breaking process of the hybrid current-limiting fuse in the arc trigger built-in solution in FIG. 6 .

The working principle of the arc trigger built-in application scheme is:

During normal operation, the current i mainly flows through the arc trigger and the breaker, and a small amount of current _i2 flows through the arc extinguishing fuse. After the short circuit occurs, the arc trigger 8 is first fused to start the arc, and the current i ₁ will immediately transfer to the arc extinguishing fuse 10. At the same time, the pulse transformer 9 sends a trigger signal Rt to the thyristor F ₀ . The bridge body needs a certain time t _a , that is, when the insulating block breaks the bridge body at time t ₂ , all or most of the current i ₁ has been transferred to the arc-extinguishing fuse 10 at this time, so the arcing energy on the breaker is extremely small After that, the insulating block 7 continues to move upwards to separate the bridge body and form a sufficient distance. t _z is the medium recovery time after the breaker current i ₁ crosses zero. At t ₃ , the arc-extinguishing fuse 10 is blown and the arcing occurs Overvoltage, this voltage is loaded across the breaker, the short-circuit current begins to drop, and eventually the circuit is completely broken.

Comparing the two application schemes of the external arc trigger and the built-in arc trigger, we can see that:

(1) The built-in scheme starts commutation at the moment of arcing of the arc trigger, while the external scheme requires the arc trigger to send a signal to the breaker and waits for the insulating block to interrupt the bridge before starting commutation. If the starting time _t0 of the arc trigger of the scheme is the same, the commutation current starting point of the built-in scheme is low, the commutation time is shorter, and the current peak value after current limiting can be lower;

(2) The breaker bridge in the built-in solution is interrupted after the commutation process is over, and the current on it is close to zero at this time, and the arcing energy formed in the breaker is very small, while the bridge in the external solution The commutation process starts when the bridge body of the breaker is interrupted to start arcing. The commutation current of the breaker is large, so it will generate a large arcing energy, which is very unfavorable to the medium recovery process.

In summary, compared with the external arc trigger solution, the arc trigger built-in solution has the advantages of early commutation time of the breaker, short commutation time, small arc energy and good dielectric recovery characteristics, which can be given priority in application Consider an arc trigger built-in solution.

The content not described in detail in this specification belongs to the prior art known to those skilled in the art.

Claims (5)

1. An electromagnetic repulsion-driven piston type high-speed breaker, characterized in that: comprise a repulsion drive circuit, a repulsion coil connected in the repulsion drive circuit, an input connection terminal and an output connection terminal, between the input connection terminal and the output connection terminal A bridge body is bridged, and an insulating sleeve is provided on the bridge body. A repulsion disk is arranged under the bridge body. The repulsion disk is located above the repulsion coil. An insulating block that can break the bridge body is fixed on the repulsion disk; The copper block and the connection blocks at the upper and lower ends, the material of the connection block is metal, and a tapered hole is opened in the center of the connection block; the central copper block is a conical structure, and the upper and lower ends of the central copper block are respectively embedded in the tapered holes of the upper and lower connection blocks , the connection blocks at the upper and lower ends are respectively connected to the input terminal and the output terminal. 2. The electromagnetic repulsion-driven piston-type high-speed breaker according to claim 1, characterized in that: the repulsion drive circuit includes a capacitor, a thyristor and a freewheeling diode connected in series, the positive electrode of the capacitor and the The negative pole is respectively connected with the negative pole of the freewheeling diode and the cathode of the thyristor, the positive pole of the freewheeling diode is connected with the anode of the thyristor, and the repulsion coil is connected in series between the capacitor and the thyristor and connected in parallel with the freewheeling diode. 3. The piston-type high-speed breaker driven by electromagnetic repulsion according to claim 1, characterized in that: the insulating sleeve is made of epoxy resin or other insulating materials; the upper and lower ends of the insulating sleeve are respectively connected to the input terminal Connect to the output terminals. 4. The electromagnetic repulsion-driven piston-type high-speed breaker according to claim 1, characterized in that: the repulsion plate is used to induce the magnetic field generated by the repulsion coil and generate electromagnetic repulsion to drive the insulating block to hit and break the bridge. plate or copper plate. 5. The high-speed piston-type breaker driven by electromagnetic repulsion according to claim 1, wherein the insulating block is made of insulating material, and the upper end of the insulating block passes through the input terminal and extends to the bottom of the bridge body.