CN115938835A - Dual-power switch arc extinguishing circuit based on power electronic technology - Google Patents

Abstract

The invention relates to a double-power switch arc extinguishing circuit based on a power electronic technology, which is technically characterized in that: the circuit breaker comprises a power electronic module, a load RL1, a diode D2, a capacitor C and a current-limiting resistor R1, wherein the B end of a circuit breaker DL1 is connected with one end of the load RL1, the A end of the circuit breaker DL1 is connected with the current-limiting resistor R1, and the other end of the current-limiting resistor R1 is connected with the B end of the circuit breaker DL1 after being connected with the capacitor C1 in series; the power electronic module is connected between the A end and the B end of the breaker DL1 in parallel; two control ends of the power electronic module are respectively connected between the current-limiting resistor R1 and the capacitor C1 and between the capacitor C1 and the load RL 1. The invention is mainly applied to the circuit breaker of the dual-power switch, can transfer the electric arc generated when the circuit breaker is switched off through the power electronic module, realizes the function of 'zero electric arc', has the characteristics of short conduction time, low cost and the like, reduces the breaking voltage of the dual-power switch, and can effectively prolong the service life of the dual-power switch.

Description

Dual-power switch arc extinguishing circuit based on power electronic technology

Technical Field

The invention belongs to the technical field of power electronics, relates to power electronic switch arc equipment, and particularly relates to a dual-power switch arc-extinguishing circuit based on a power electronic technology.

Background

Dual power switches (circuit breakers) assume vital on and off roles in low voltage power systems. When the circuit breaker at one end of the dual-power switch is disconnected, if the circuit voltage is less than 10-20V or the current is more than 80-100mA, electric arcs can be generated between the switch contacts. Arc current when the switch is arcing is difficult to extinguish, if not controlled, can influence life to damaging the switch contact to can produce huge heat, cause serious threat to the safety of other electrical equipment on every side. Meanwhile, the breaker switch needs a certain insulation recovery time after the arcing is cut off, so that the time for breaking the circuit is prolonged, and the requirement of the dual power switch Guan Su mobility is difficult to meet.

The traditional mechanical switch usually adopts the methods of controlling the dissociating degree and the dissociating degree of an arc gap medium, controlling the temperature of the arc gap and increasing the voltage between the arc gaps to extinguish arc, adopts the specific arc gap medium, increases the distance of the arc gaps, changes the path of an arc column, improves the breaking speed, increases the opening distance between contacts and the like. However, the traditional mechanical and physical arc extinguishing method not only has strict technical requirements on the structural design of a mechanical switch, but also has the defects of long arc breaking time (millisecond level), short electrical service life (several times to thousands of times), large volume and low cost performance in application. The electronic arc extinguishing method for manufacturing the current zero point by using the resonance has strict requirements on the mechanical switch, and the resonance parameters need to be adjusted according to the actual application working conditions of the mechanical switch, so that the universality of application is limited. Therefore, the choice and design of switching applications has to be faced with the problems and faults associated with arcing.

The root of the difficulty in eliminating the electric arc lies in that the inductive load current cannot suddenly change, and the electric arc current generated after the contact of the circuit breaker is segmented has a natural zero-crossing process, so that the time for really realizing the electric isolation of the circuit breaker is greatly delayed. Especially in the occasion of dual power source open-close work, when the electric arc of former side power can not extinguish, just can't insert the power use of reserve side, lead to in dual power source switch's switching occasion, the single switching process just can be up to tens of ms, can't avoid the load side to have a power failure, just also violated dual power source switch's design original intention.

In summary, how to rapidly process the arc in the breaking process of the switch to realize the low-voltage uninterrupted operation of the dual-power circuit and zero power failure in maintenance and construction is a problem which needs to be solved urgently at present.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a dual-power switch arc-extinguishing circuit based on a power electronic technology, can process electric arcs in the switch breaking process to extinguish the electric arcs as soon as possible without natural zero crossing, and simultaneously designs an energy-absorbing branch to limit the voltage to a safe level, thereby realizing low-voltage uninterrupted operation and zero power failure in maintenance construction of the dual-power circuit.

The technical problem to be solved by the invention is realized by adopting the following technical scheme:

a dual-power switch arc-extinguishing circuit based on a power electronic technology is connected to a breaker DL1 and comprises a power electronic module, a load RL1, a diode D2, a capacitor C and a current-limiting resistor R1, wherein the end B of the breaker DL1 is connected with one end of the load RL1, the end A of the breaker DL1 is connected with the current-limiting resistor R1, and the other end of the current-limiting resistor R1 is connected with the end B of the breaker DL1 after being connected with the capacitor C1 in series; the power electronic module is connected between the A end and the B end of the circuit breaker DL1 in parallel; two control ends of the power electronic module are respectively connected between the current-limiting resistor R1 and the capacitor C1 and between the capacitor C1 and the load RL 1.

Further, the power electronic module is formed by reversely connecting a power electronic device Q1 and a power electronic device Q2 in series, and the power electronic device Q1 and the power electronic device Q2 are both semi-controlled power electronic devices.

Further, the power electronic device Q1 and the power electronic device Q2 are provided with diodes, or the power electronic device Q1 and the power electronic device Q2 are respectively connected with a diode D1 and a diode D2 in parallel; power electronics Q1 and diode D2 and power electronics Q2 and diode D1 are all in anti-series relationship.

Further, the power electronic module is formed by reversely connecting a power electronic device Q1 and a power electronic device Q2 in parallel, and the power electronic device Q1 and the power electronic device Q2 are all fully-controlled power electronic devices.

Further, the power electronic device Q1 and the power electronic device Q2 are an IGBT, an NPN-type triode, or an N-channel field effect transistor.

Further, a high voltage arrester group MOV is connected in parallel between the end A and the end B of the breaker DL1, and the high voltage arrester group MOV forms an energy absorption branch.

Furthermore, a delay circuit is connected to the power electronic module.

The invention has the advantages and positive effects that:

1. according to the characteristics of electric arcs generated by the breaker switch, a power electronic device based on an electronic arc extinguishing technology is connected with the breaker switch in parallel, the current on the switch is shunted in the breaking process of the switch, and the voltage at two ends of the switch is limited to a lower level of several volts, so that the conditions of strong electric field emission and thermionic emission necessary for generating the electric arcs are prevented, the current is transferred to a preset current conversion branch circuit, the mechanical contact of the breaker is broken under the arc-free condition, the final fault current breaking is completed by the transfer branch circuit, the electric arcs of a primary side power supply are extinguished, and a standby side power supply is connected, so that the switching time of a low-voltage alternating current dual-power supply system is shortened, and the uninterrupted operation function of a power distribution network is realized.

2. The invention is independent of the switch, can be used with the existing switch, and has the advantages of large overload capacity, low temperature rise and convenient use. The electric arc current on the switch is shunted in the breaking process of the switch, and the voltage at two ends of the switch is limited to a lower level of several volts, so that the function of zero electric arc of the dual-power switch in the switching process is realized. The invention is different from the conventional low-voltage switch which uses the air arc-extinguishing grid, improves the fire-fighting level, does not need to wait for the occurrence of electric arc and then carry out arc-extinguishing treatment, and avoids the occurrence of electric arc in the whole process. The switching time is greatly shortened (less than or equal to 10 ms) by adopting the power electronic technology, and compared with other arc extinguishing modes, the arc extinguishing device is basically lossless and is a typical green product.

Drawings

FIG. 1 is a circuit diagram of embodiment 1 of the present invention;

FIG. 2 is a circuit diagram according to embodiment 2 of the present invention;

FIG. 3 is a circuit diagram of the delay circuit of the present invention;

FIG. 4 is a graph of the load side current waveform of the present invention;

fig. 5 is an equivalent diagram of the breaking process in the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The design idea of the invention is as follows: the invention provides a double-power switch arc extinguishing circuit based on a power electronic technology, which is independent of a switch and can be matched with the existing switch for use. It connects the power electronics in parallel with the switch so that the voltage across the switch is limited to a low level of several volts, thereby preventing the conditions of strong electric field emission and thermionic emission establishment necessary to produce an arc. An arc current transfer branch is designed, and the generated arc current is introduced into the transfer branch by utilizing the current transfer principle, so that the switching time of the dual-power switch is shortened, and the uninterrupted power supply of a load side is ensured. The energy absorption branch is designed, and the circuit breaker is switched on to release energy after being switched off, so that the induced electromotive force generated by sudden change of current of an inductive element in a direct current circuit is prevented from puncturing a power electronic switch on the current conversion branch.

Example 1

A dual-power switch arc extinguishing circuit based on a power electronic technology is shown in figure 1, and is connected to a circuit breaker DL1 and comprises a power electronic device Q1, a power electronic device Q2, a load RL1, a diode D2, a capacitor C and a current-limiting resistor R1.

The circuit breaker DL1 comprises an A end (power input end) and a B end, the B end of the circuit breaker DL1 is connected with one end of a load RL1, the A end of the circuit breaker DL1 is connected with a current-limiting resistor R1, and the other end of the current-limiting resistor R1 is connected with a capacitor C1 in series and then connected with the B end of the circuit breaker DL 1. The power electronic device Q1 and the power electronic device Q2 are semi-controlled power electronic devices, the power electronic device Q1 and the power electronic device Q2 are connected in series in an anti-reverse mode to form a power electronic module in a virtual frame in the figure 1, and the power electronic module forms a current transfer branch. The power electronics module is connected in parallel between terminals a and B of the circuit breaker DL 1. The control end of the power electronic device Q1 is connected between the current limiting resistor R1 and the capacitor C1, and the control end of the power electronic device Q2 is connected between the capacitor C1 and the load RL 1.

The power electronic devices Q1 and Q2 can be IGBTs, NPN type triodes or N-channel field effect transistors. In the present embodiment, the power electronic devices Q1 and Q2 employ IGBTs.

The power electronic device Q1 and the power electronic device Q2 may be self-contained diodes D1 and D2, and also may be separately connected in parallel with the external diodes D1 and D2, the power electronic device Q1 and the diode D2, or the power electronic device Q2 and the diode D1 are in an anti-series relationship.

In fig. 1, the a terminal of the breaker DL1 is connected to the collector (C) of the power electronic device Q1 and the cathode terminal of the diode D1, and the emitter (E) of the power electronic device Q1, the anode terminal of the diode D1, the emitter (E) of the power electronic device Q2, and the anode terminal of the diode D2. The terminal B of the breaker DL1 is connected to the collector (C) of the half-controlled power electronic device Q2 and the cathode terminal of the diode D2. At the moment, the power electronic device Q1 is connected with the positive end of the diode D1 and then connected with the semi-controlled power electronic device Q2 and the positive end of the diode D2. This means that Q1 and Q2 are connected in series between the two end contacts of the breaker DL1, and diodes D1 and D2 are connected in parallel to Q1 and Q2, respectively.

In the circuit, a current limiting resistor R1 and a capacitor C1 form a charging unit, and the capacitor C1 is connected to an a terminal (power input terminal) of a breaker DL1 through the current limiting resistor R1.

According to the invention, the power electronic module is connected in parallel between the circuit breakers DL1, so that the bidirectional current is ensured to have a channel on the parallel branch of the circuit breaker DL, zero arc can be realized, the process of natural zero crossing of the arc current is not needed, and the uninterrupted power supply of the load side is ensured.

The working process of the embodiment is as follows:

when the system operates normally, the breaker switch DL1 is closed and energized, and current flows through the main circuit. The power supply charges the capacitor C through the current limiting resistor R1.

When a circuit is in fault, in the process of opening the breaker switch DL1, when the potential difference of the capacitor C1 end to the load RL1 is greater than the opening voltage of the power electronic device Q1 or Q2 (the potential difference is approximately equal to the potential difference of the two ends of the breaker switch), the semi-controlled power electronic device Q1 or Q2 is triggered to be conducted. The capacitor C1 forms a loop through a collector and an emitter of the semi-controlled power electronic device Q1 or Q2, and the arc current is transferred to the power electronic module branch. The electric field intensity between the contacts of the breaker switch DL1 is rapidly reduced, so that the rapid arc extinction of the breaker switch DL1 is completed.

The capacitor C1 discharges the load RL through the half-controlled power electronic device Q1 or Q2, the current is consumed in the power electronic module, and the power electronic devices Q1 and Q2 are turned off.

At the moment, the electric arc between the contacts of the primary side power circuit breaker of the dual-power switch is extinguished, the primary side power circuit breaker is automatically switched to another power supply, and the standby power supply is put into use.

In this embodiment, only current flows through the power electronics module during the arc treatment, and no arc is generated between the contacts. The input end and the output end of the power electronic module are isolated in a non-insulated way, and the charging power supply of the capacitor is provided by the current limiting of a main loop power supply of a breaker switch. The anti-series connection of power electronics Q1 and power electronics Q2 ensures that both currents are in the path of the bi-directional current. In the breaking process of the breaker switch, the base of the power electronic device does not need to be connected with a resistor in series for current limiting, so that the loss of capacitance charges before the power electronic device is switched on is reduced, and the triggering speed of the power electronic device is increased. And meanwhile, the resistor is used for limiting current when the capacitor is charged, so that the current impact when the breaker is switched on and off is reduced. The capacitor is connected to the breaker switch and the load, and is charged by using the main loop power supply, so that the insulation and voltage resistance at two ends of the switch are not influenced, and leakage current is avoided when the breaker switch is in a disconnected state.

In actual use, when the requirement on the arc extinguishing speed is not high, a delay circuit can be used on a power electronic device in a power electronic module, the delay circuit comprises a resistor R2, a resistor R3 and a capacitor CL1 as shown in FIG. 3, the resistor R2 and the capacitor CL1 are connected in series and then connected between a collector and an emitter of the Q1, one end of the resistor R3 is connected with a grid of the Q1, and the other end of the resistor R3 is connected between the resistor R2 and the capacitor CL 1. The circuit breaker can be ensured to keep enough opening distance after the switch of the circuit breaker is disconnected through the delay circuit, and the electric arc is prevented from reigniting after the arc is extinguished.

Example 2

A switching arc processing device based on power electronics is shown in figure 2 and comprises a breaker DL1, a power electronic device Q2, a load RL1, a capacitor C, a current limiting resistor R1 and a high-voltage arrester group MOV.

The main differences between this example 2 and example 1 are: the power electronic devices Q1 and Q2 in the present embodiment are fully-controlled power electronic devices, and the power electronic devices Q1 and Q2 are in an antiparallel relationship.

The specific connection relationship of the circuit is as follows: the circuit breaker DL1 comprises an A end (power input end) and a B end, the B end of the circuit breaker DL1 is connected with one end of a load RL1, the A end of the circuit breaker DL1 is connected with a current-limiting resistor R1, and the other end of the current-limiting resistor R1 is connected with a capacitor C1 in series and then connected with the B end of the circuit breaker DL 1. The power electronic device Q1 and the power electronic device Q2 are all fully-controlled power electronic devices, the power electronic device Q1 and the power electronic device Q2 are connected in an anti-parallel mode to form a power electronic module in a virtual frame of a figure 2, and the power electronic module forms a current transfer branch. The power electronics module is connected in parallel between terminals a and B of the circuit breaker DL 1. The control end (G) of the power electronic device Q2 is connected between the current limiting resistor R1 and the capacitor C1, and the control end (G) of the power electronic device Q1 is connected between the capacitor C1 and the load RL 1.

Two ends of the MOV of the high-voltage arrester group are respectively connected with a A, B end pin of the circuit breaker DL1 to form an energy absorption branch. The high-voltage arrester group can be a piezoresistor or a metal oxide arrester, and is punctured before the power electronic device in a manner similar to automatic lightning triggering, so that the purpose of protection is achieved, and the high-voltage arrester group automatically recovers to a completely insulated high-resistance state after the energy discharge is finished. Two ends of the MOV of the high-voltage arrester group are respectively connected with a A, B end pin of the circuit breaker DL1 to form an energy absorption branch.

It should be noted that the energy absorption branch formed by the MOV of the high-voltage arrester group can also be used in the arc extinguishing circuit of embodiment 1.

The working process of the embodiment is as follows:

the arc striking and extinguishing principle of the embodiment is similar to that of the embodiment 1, and the difference is that the embodiment uses fully-controlled power electronic devices Q1 and Q2 without diodes, and the power electronic devices Q1 and Q2 can control the turn-off of the power electronic devices. Two ends of an MOV of the high-voltage arrester group are respectively connected with a A, B end pin of the circuit breaker DL1 to form an energy absorption branch.

When the system operates normally, the breaker switch DL1 is closed and energized, and current flows through the main circuit. The power supply charges the capacitor C through the current limiting resistor R1.

When a circuit is in fault, in the process of opening the breaker switch DL1, when the potential difference of the capacitor C1 end to the load RL1 is greater than the opening voltage of the power electronic device Q1 or Q2 (the potential difference is approximately equal to the potential difference of the two ends of the breaker switch), the fully-controlled power electronic device Q1 or Q2 is triggered to be switched on. The capacitor C1 forms a loop through a collector and an emitter of the fully-controlled power electronic device Q1 or Q2, and the arc current is transferred to a power electronic module branch. The electric field intensity between the contacts of the breaker switch DL1 is rapidly reduced, so that the rapid arc extinction of the breaker switch DL1 is completed.

At the moment, the arc between the contacts of the original side power circuit breaker of the dual-power switch is extinguished, the circuit breaker is automatically switched to another power supply, and the standby power supply is put into use.

The embodiment is suitable for being used in a circuit with an inductive load, the inductive current of the circuit cannot change suddenly due to the inductive load, the arrester MOV is connected into the circuit, the situation that the induced electromotive force generated by the inductive current is too large to cause breakdown of a power electronic device is prevented, after the power electronic device is turned off, the fault current is transferred to the MOV energy absorption branch of the arrester, and the arrester MOV starts to absorb energy until the fault current is reduced to zero, so that the whole fault current breaking process is completed. The current and voltage variation trend of the system and each part of the circuit breaker in the whole arc extinction control process is shown in figure 5.

In this embodiment, the fully-controlled power electronic device can be driven by different driving voltages respectively. Preferably, a control unit with a built-in programmable controller may be used. The voltage signal of the capacitor and the voltage signal of the connecting end of the breaker switch and the load can be sampled, and the appropriate breaking control mode can be selected in a self-adaptive mode. The control mode can be adjusted according to voltage change by using the control unit, so that the circuit is simplified, the arc extinguishing effect is improved, and the service life of the dual-power switch is effectively prolonged.

The two embodiments show that the invention is mainly applied to the circuit breaker of the dual-power switch, and the circuit is formed by arranging the power electronic devices, so that the arc generated when the circuit breaker is switched off is transferred, and the assumption of 'zero arc' is realized. The power electronic module is used, the circuit is simple, and the conduction of a power electronic device is realized by utilizing the fact that a large potential difference is formed between the capacitor and the load after the switch is disconnected. The arc extinguishing problem of the 0.4kV dual-power mutual-throw switch in use is solved by utilizing the advantages of large overload capacity, short conduction time, low cost and the like of the power electronic device. The parallel power electronic modules reduce the breaking voltage of the dual-power switch, and can effectively prolong the service life of the dual-power switch.

The dual-power switch arc-extinguishing circuit based on the power electronic technology can also be connected with a control unit, the control unit is a programmable device and is connected with a power electronic device Q1, and the power electronic device Q1 receives instructions and data sent by the control unit and transmits external information states (such as a circuit breaker switch state, a load state and the like) of the circuit, so that an intelligent control function is realized.

The working principle of the invention is as follows: after the breaker switch DL1 to be extinguished is closed, the power supply charges the capacitor C1 quickly through the current limiting resistor R1. When the breaker switch is disconnected, an electric arc current is generated between the contacts, when the breaker switch is disconnected and the potential difference between the breaker switch DL1 and the capacitor C1 is larger than the starting voltage of the power electronic module, a semiconductor device in the power electronic module is triggered to be conducted, the electric arc is transferred to a branch circuit of the power electronic module, the current at two ends of the breaker switch is rapidly reduced to 0, and the capacitor C1 rapidly discharges to the load RL1 through the power electronic device Q1 or Q2. The electric field intensity between the contacts of the circuit breaker DL1 is rapidly reduced; after the switching condition is met, the dual-power switch is switched from the primary power supply to the standby power supply; the power electronic device Q1 or Q2 is triggered to be turned off; the current on Q1 or Q2 is off. Therefore, the aim of arc-free breaking of the breaker switch DL1 is fulfilled.

The arc waveform obtained by the present invention is shown in fig. 4 (a) and (b), wherein the lower picture is a partial amplified waveform of the upper picture, and pink is a load-side current. The graph clearly shows that the waveform of the first half section is the electric arc generated at the moment of opening the contacts, the electric arc between the contacts is led out through the intervention of the electric arc processing circuit, so that the second half section of the waveform tends to be zero, the electric arc is completely eradicated in the whole process, the current is led out by utilizing the power electronic topological circuit, the electric arc is not generated between the contacts of the switch in the switching process, and the aim of non-electric arc breaking of the switch is fulfilled.

It should be emphasized that the embodiments described herein are illustrative rather than restrictive, and thus the present invention is not limited to the embodiments described in the detailed description, but also includes other embodiments that can be derived from the technical solutions of the present invention by those skilled in the art.

Claims (7)

1. The utility model provides a dual supply switch arc extinguishing circuit based on power electronic technology, connects on circuit breaker DL1, its characterized in that: the circuit breaker comprises a power electronic module, a load RL1, a diode D2, a capacitor C and a current-limiting resistor R1, wherein the B end of a circuit breaker DL1 is connected with one end of the load RL1, the A end of the circuit breaker DL1 is connected with the current-limiting resistor R1, and the other end of the current-limiting resistor R1 is connected with the B end of the circuit breaker DL1 after being connected with the capacitor C1 in series; the power electronic module is connected between the A end and the B end of the circuit breaker DL1 in parallel; two control ends of the power electronic module are respectively connected between the current-limiting resistor R1 and the capacitor C1 and between the capacitor C1 and the load RL 1.

2. The dual power on Guan Miehu circuit based on power electronic technology of claim 1, wherein: the power electronic module is formed by reversely connecting a power electronic device Q1 and a power electronic device Q2 in series, and the power electronic device Q1 and the power electronic device Q2 are semi-controlled power electronic devices.

3. The dual power on Guan Miehu circuit based on power electronic technology of claim 2, wherein: the power electronic device Q1 and the power electronic device Q2 are provided with diodes, or the power electronic device Q1 and the power electronic device Q2 are respectively connected with a diode D1 and a diode D2 in parallel; power electronics Q1 and diode D2 and power electronics Q2 and diode D1 are all in anti-series relationship.

4. The dual power on Guan Miehu circuit based on power electronic technology of claim 1, wherein: the power electronic module is formed by reversely connecting a power electronic device Q1 and a power electronic device Q2 in parallel, wherein the power electronic device Q1 and the power electronic device Q2 are all fully-controlled power electronic devices.

5. The dual power on Guan Miehu circuit based on power electronic technology of claim 2 or 4, wherein: the power electronic device Q1 and the power electronic device Q2 are IGBT, NPN type triodes or N channel field effect transistors.

6. The dual power on Guan Miehu circuit based on power electronic technology of claim 1, wherein: and an MOV (metal oxide varistor) of a high-voltage arrester group is connected between the end A and the end B of the circuit breaker DL1 in parallel, and the MOV of the high-voltage arrester group forms an energy absorption branch.

7. The dual power on Guan Miehu circuit based on power electronic technology of claim 1, wherein: and the power electronic module is also connected with a delay circuit.

Images