KR101387730B1 - Trigger circuit and switching device using the same - Google Patents

Abstract

The present invention relates to a trigger circuit necessary for power control and protection of a power facility and a switching device using the same. In particular, the thermal resistance shortage, that is, the weak point of a power electronic switching device (triac, SCR, power transistor, etc.) Power electronic switching device trigger circuit that can prevent the destruction of switching device in case of short circuit accidents is protected, it protects the power electronic switching device in case of short circuit, separates the fault point, and the circuit breaker function to cut off over current The present invention relates to a switching device having a circuit breaker function having a circuit breaker function for blocking leakage current and a relay function capable of remote operation, and having various configurations such as a circuit breaker having a function of automatically recovering according to the type or nature of a load. And for the manager's effective facility management, By making the type indication as to provide a small economical trigger has a breaker function and the relay function in a combination circuit and a switching device using the same.

Description

Trigger circuit and switching device using the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching device required for power control and protection of power equipment. In particular, a switching device in case of a short circuit fault of a load-side circuit, which is a weak point of a power electronic switching device such as a triac, an SCR, a power transistor, and the like, is caused. It is equipped with a trigger circuit that prevents the breakdown of the circuit, protects the power electronic switching element during a short circuit, separates the fault point, a circuit breaker that cuts off the overcurrent, and an earth leakage breaker that cuts off the leakage current. The present invention relates to a switching device having a composite relay function capable of remote operation.

In general, all power facilities have a breakdown device and a control device for the operation of the power device in order to separate the fault points for the stable and continuous power supply of the power system and to safely use the electric energy. It consists of a combination of a switching device (breaker) with a blocking function and a switching device (relay) for control.

When describing the structure, the breaker device generally has a mechanical mechanism and the ability to withstand the fault breaking capacity of the fault point, and has a structure that is physically separated from the power circuit at the time of breakage, and the control device has a contact point or It is a contactless relay that has no switching function and has switching capability to handle the operating current. In case of a short circuit, the protection of the relay itself is configured to cooperate with the circuit breaker.

Therefore, the breaking device should be guaranteed to be open and close even in the event of an extreme fault such as a short circuit, and the control device should not lose or break its capacity even at the fault current of the extreme during the time the breaker breaks.

1 shows an example of a trigger circuit of a power electronic switching element that is used in the related art. When this is explained, when an input signal current flows through the control input terminal Cnt, the phototriac PT is turned on so that the resistor R1 is applied. -Photo Triac (PT)-The current supplied through the power line (P) flows to the resistor (R2), the triac (TRI) is turned on.

Therefore, the triac TRI is turned on in synchronization with an arbitrary phase in which the input signal current is applied to the port triac PT.

However, since the trigger power of various power electronic switching devices (triac, SCR, power transistors, etc.) including triacs is using an external power source that is independent of the load power source, the on-signal is always input even in case of failure. The countermeasure in case of a failure on the power load side is not considered.

Therefore, if there is no additional protective device (constant speed fuse, etc.) that cooperates with protection when the current rises rapidly due to a short circuit on the load side, or the operation is delayed, the breakdown of the power electronic switching device with insufficient thermal tolerance occurs.

As a result, power electronic switching devices (triacs, SCRs, power transistors, etc.) are widely used in various fields with many advantages as elements of control devices, but in case of extreme failures such as short circuit accidents due to their low thermal resistance In this case, it was broken and kept closed, and it was impossible to apply it as a breaker.

In order to solve this problem, in order to protect the power electronic switching device itself separately from the blocking device for coordinating the protection of the power electronic switching device, a high speed circuit breaker connected in series with a fast fuse or a dedicated protection device for each power electronic switching device is used. Although operating in addition to the control device, there are many problems in application because the control device for this is complicated and expensive.

In addition, when the power is cut off by the operation of the breaker, it recognizes the cause of the failure, and even though the failure is solved, it is inevitably moved to the breaker installation place for the recovery of the breaker, and has to have the disadvantage of manually repairing the breaker.

This action causes safety accidents and economic losses during recovery, and increases the stoppage time, and further damages occur when the installation site is remote.

Therefore, in order to solve the conventional problem that the thermal resistance is insufficient to use the contactless power electronic switching device as the device of the blocking device, the trigger circuit of the power electronic switching device is newly configured to instantaneously in case of an accident such as a short circuit. By eliminating and turning off the power of the gate control switch at 100us or less, the thermal capacity passing through is reduced to the maximum, protecting the power electronic switching element itself, and maintaining the fault line selection blocking to isolate the fault point, thereby providing the basic ability of the circuit breaker. In addition, the purpose of the present invention is to provide a switching device for using a contactless power electronic device as a blocking device.

Also, trigger circuits can be used for power electronic switching devices such as triacs, SCRs, power transistors, IGBTs, GTOs, and so on for power control for energy saving in power systems. Another purpose is to compensate for the weak points of the electronic switching device for power by using the power electronic switching device can be used easily and stably without damage in the power system.

In addition, there is another purpose to improve the reliability, stability and safety of the power equipment by mounting a variety of electronic devices using the characteristics that operate at high speed.

For example, branch circuits may be installed in a plurality of load equipments connected to the same branch circuit (light fixtures, a plurality of power equipment computers connected to the same branch circuit as an outlet circuit, etc.) and each branch circuit may be caused by a failure of one point of the load equipment. The purpose of this is to prevent interruption of work due to the blocking and to enable high speed separation of only one point of failure.

In addition, it has a blocking ability to isolate fault points without damage to power electronic devices even in the event of an extreme short circuit, and can be controlled like a solid state relay, so it can be controlled manually, automatically, and remotely for individual and collective operation of power load. Another aim is to provide a relay that is easy to use, improves existing installations, and can be economically and easily applied to new facilities.

In addition, it is another object to provide a circuit breaker capable of remote control by adding an overcurrent detection circuit.

In addition, another object of the present invention is to provide an earth leakage breaker capable of remote control by adding an earth leakage breaker circuit.

In addition, the present invention provides a circuit breaker capable of short-circuit protection, over-current protection, short-circuit protection, ground fault protection, and remote control by adding an overcurrent cutoff and a ground fault interrupting circuit.

The switching device of the present invention for achieving the above object is to operate the switch power supply for the gate circuit control in accordance with the potential state of the potential point connected between the lines in parallel with the load so that the circuit connected to the electronic switch is involved in a short circuit. The device turns off instantly during sudden voltage drops to prevent the short circuit current from passing through, protecting the electronic switching device for power, and maintaining fault interruption using fault signals detected by fault detection units such as overcurrent, ground fault, and short circuit. It protects the power electronic switching device and at the same time has a function as a circuit breaker and a relay.

This invention has the following effects.

1. In case of short-circuit accident, the fault current is separated at high speed (less than 100kW), the fault current is limited and the sudden voltage drop of the normal circuit is reduced, so the stability of the power system is increased and the amount of thermal energy passed through. As it becomes small, the action as a ignition source is reduced.

2. In case of a short circuit, the power electronic switching devices (triac, SCR, power transistor) are not damaged, so there is no need for fast-speed fuse or high-speed circuit breaker to protect the device. do.

3. Since remote operation is possible, separate relay installation is unnecessary and lifespan is semi-permanent because it is contactless.

4. The high speed operation minimizes the fault range of the power system. As an example of a short-circuit accident, the power system is configured such that a plurality of circuit breakers are connected in series in order to supply power to the terminal power load, and the plurality of circuit breakers operate in mutual protection coordination with different breaking capacities. However, in the case of a short circuit fault, the plurality of circuit breakers have insufficient breaking capability or different breaking times depending on the magnitude of the short-circuit current passing through them. Therefore, in case of short-circuit accident of the line of the final load connected to the earth leakage breaker, there is a frequent case of extending the power failure range by operating the upper breaker which has the faster operation time than the earth leakage breaker.

5. As it is composed of electronic circuit, it is possible to set the protection range by simple operation according to the type of load and to add necessary functions such as automatic recovery.

6. It can be easily applied to existing power equipment at low price.

7. When not in use, the electric circuit is turned off, so a separate device for shutting off standby power of connected individual power equipment is unnecessary.

8. It has performance and structure suitable for national power management such as smart grid, and has various advantages of contactless relay such as noiseless and economical and compact.

1 is a general trigger circuit diagram.
2 is a circuit diagram of a switching device according to the present invention.
3 is a detailed circuit diagram of a switching device in which a failure maintenance unit is added to the circuit of FIG.
4 is a detailed circuit diagram of a switching device in which a switching device control unit is added to the circuit of FIG.
Fig. 5 is a detailed circuit diagram of the switching device in the case where the switching device is three phase of the present invention.
6 is a detailed circuit diagram of a switching device for DC of the present invention.

The present invention configured as described above will be described in detail with reference to the accompanying drawings.

2 shows a detailed circuit diagram of the switching device 100 according to the present invention. First, the trigger circuit 500 will be described. The start potential forming unit 510 and the gate power control unit 520 are provided.

The load power is not supplied or constant by triggering the power electronic switching device 400 using the line voltage of the load 600 of the gate circuit control switch PT2 of the power electronic switching device 400. It has a structure that does not operate when the voltage is lower than the voltage.

Therefore, in the event of a short circuit, the power supply for the gate circuit control switch PT2 is reduced to the zero potential by the accompanying instantaneous voltage drop, thereby turning off the power electronic switching device 400 in an instant (100us or less).

The instantaneous high-speed operation of the power electronic switching device 400 is limited by the heat capacity passing through the fault current of the extreme, such as a short circuit is turned off by the high speed operation to prevent damage to the power electronic switching device 400. As a result, it has the ability as a blocking device and enables a stable operation.

Referring to the structure and operation of the trigger circuit 500 according to the present invention in detail, the power supply for the operation of the gate circuit control switch (PT2) is a potential line connecting between the power supply line (P, N) between the load line of the gate circuit control switch It is formed through a (PT2), the capacitor line (Ca1) is installed in series with the resistor (Ra1) in parallel with the resistor (Ra1) as a rectifier circuit of the transformerless type to generate a DC power in the potential line. BR1) is installed to be used as a DC power supply for the gate circuit control switch PT2, and another power supply device may be used.

In addition, this rectifier circuit has a structure in which the DC power supply is continuously output when the gate circuit control switch PT2 is turned on and a potential is formed at the potential point P1.

Therefore, since the switch PT2 is turned off at the start of the on-operation during the operation stop, the power electronic switching device 400 cannot operate even when the power supply for the trigger circuit control is turned on.

In the present invention, the capacitor (Ca2) in series with the switch (PT1) connected in parallel with the anode and cathode terminals of the power electronic switching device 400 to form a potential at the potential point (P1) when the trigger circuit control signal is turned on When the trigger circuit control signal is turned on, by operating the switch PT1, a potential is formed at the potential point P2 during charge and discharge of the capacitor Ca2 connected in series so that a voltage is applied to the potential point P1. At the same time, the DC power is output from the rectifier circuit BR1 and the switch PT2 is turned on so that the rectifier circuit BR1 is self-maintained and the trigger DC power output is maintained regardless of whether the capacitor Ca2 is discharged. Finally, the power electronic switching device 400 is triggered on, and the load 600 operates by receiving power from the power lines N and P. FIG.

It is configured such that the rectified DC power is supplied to the switch PT2 only when the switching control unit 200 is on, the fault interruption maintaining unit 300 is in the off state, and the switch pc1 composed of the photocoupler is on.

On the other hand, the switching control unit 200 uses a transformer to draw DC power of the appropriate voltage, or as a transformerless operation power supply for miniaturization, the voltage adjusted by the series voltage dividing of the resistor and the capacitor in parallel from the resistance terminal. With the structure of drawing out, of condenser, resistor and diode connected in series and limiting the output voltage rise by varistor on the secondary side of the diode, or of DC power supply circuit without other transformer, or separately Can be taken out from the power supply.

To this end, a resistor Ra3 and a capacitor Ca3 are connected in series between the load lines, and a bridge diode BR3 is installed in parallel with the resistor Ra3.

The control signal for controlling the operation of the bridge diode BR3 is applied through a switch (MAN / REMOTE), the switch in the 'MAN' state is manually turned on, and the switch in the 'REMOTE' state supplies a dielectric source from the outside. Select one of DUAL MODE of method and non-power (contact) method to operate.

In addition, the switching controller 200 is driven by receiving a signal provided from the remote controller 800 through a wired / wireless communication network or separately provided from the outside.

The switching device 100 is short circuited. It has a failure maintaining unit 300 to maintain the failure blocking in the event of a ground fault, overcurrent, leakage.

The fault interruption maintaining unit 300 is a smoothing capacitor C1 in parallel with the bridge rectifier BR3 of the switching control unit 200, a plurality of fault interruption thyristors Th1,..., Thn and the trigger circuit 500. Switches pc1 are connected in parallel to each other, a resistor R2 is connected in series at one side of the parallel circuit of the capacitor C1 and the thyristor Th1, and one side of the capacitor C1 and the base of the thyristor Th1. The terminal is connected to the thyristor (Th1) gate terminal with a switch (pc2) which is operated with a voltage generated at the time of short-circuit with the resistor (R3).

A plurality of switches pcn are connected in parallel to the switch pc2, and each has a structure connected to the gate terminal of the thyristor Thn.

In case of an accident, in order to selectively shut down the fault line, the current transformer (or image current transformer) CT is connected to the power line P to which the switching element 400 is connected at the input side of each switch pc2, ..., pcn. ..., ZCT) is installed to have a structure to select fault line.

Referring to the operation of the switching device 100 according to the present invention when a load in a steady state is connected, power supply is started to the load 600 only when a potential is formed at the potential point P1, and the potential point P1 is applied. The potential of is generated only when the switch PT2 is turned on. In order for the switch PT2 to be turned on, the capacitor Ca2 and the switch PT1 connected in parallel with the A2 and A1 terminals of the power electronic switching device 400 are turned on. The series circuit of is operated so that the capacitor Ca2 starts to discharge.

Therefore, as soon as the user manipulates the switching controller 200, the switch PT1 is turned on, the capacitor Ca2 starts charging and discharging, and the switch PT2 is turned on, and the potential is turned on at the potential point P1. Since the DC power is output from the rectifier circuit configured in the potential line, and the switch PT2 is turned on, the rectifier circuit is self-maintained, and the trigger voltage is continuously supplied to the gate terminal of the power electronic switching device 400. Power the load.

Referring to the operation of the fault interruption maintaining unit 300 in the event of a short circuit during normal operation, when a short circuit occurs, the potential point P1 becomes '0' potential at the moment and the current of the current transformers CT, ..., ZCT Regardless of the operation, the switch PT2 is momentarily turned off and the electronic switching device 400 is turned off, and at the same time, the voltage detected by the current transformers CT,... By operating the thyristors Th1 and Th2, the operation voltage is not supplied to the switch pc1 and the switch PT2, so that the capacitor Ca2 also stops charging and discharging. As a result, the switching element 400 is turned off. The power supply will be stopped.

In addition, the failure state is maintained by the failure blocking maintenance unit 300 and the failure maintenance is managed by the operator's operation.

In the case where the load starts operation in the short-circuit failure state, the potential of the potential point P1 is formed once by charging and discharging of the capacitor Ca2 during the on operation, and the potential point P1 is a short-circuit state, so it is' 0. 'The potential becomes inoperable state, and maintains the blocking state by the failure blocking maintaining unit (300).

Meanwhile, in the present invention, a contact state display unit 410 for displaying the open / closed state of the power electronic switching device 400 is added, and the power electronic switching device 400 connected to the circuit can be determined and displayed. Therefore, it is possible to determine whether the malfunction of the power electronic switching device 400 is broken, such as malfunction.

Referring to the configuration and operation of the contact state display unit 410, the bridge diode BR2 is connected in parallel with the anode and cathode sides of the power electronic switching element 400 through the resistor Rpa, and the bridge diode BR2. And a resistor Rpd connected in series with the light emitting diode LED1 on the secondary side of the.

The status display turns on when the power electronic switching element 400 is turned off, and turns off when the power electronic switching element 400 is turned on.

3 shows an example of supplying a separate control power from the outside, the switching control unit 200 of FIG. 2 is removed, and triggers the control power (Cnt) directly from the outside through the failure blocking maintaining unit 300 An example of the case where the circuit 500 is supplied is shown.

Figure 4 shows a state in which the present invention is applied for the operation of a contactless relay having a device protection function in the event of a short circuit of the power device, the switching control unit 200 and the fault interruption maintenance unit 300 is removed, the control power ( Cnt) is a structure that is turned on / off in conjunction with a load, and maintains blocking in a short-circuit state and automatically recovers when the cause is removed.

Figure 5 shows a state in which the present invention is applied to a three-phase circuit, the switching device is installed between each of the power lines (R, S, T) of each of the three phases, and is controlled by a single control power supply via the fault interruption maintaining unit. The short-circuit current of each phase is protected by a trigger circuit configured for each phase, and the failure blocking maintenance unit 300 operates by a signal detected by the failure detection unit 700 installed for each phase, thereby enabling the failure blocking.

6 shows a state in which the DC circuit is applied, the switch pc1 of the photocoupler is operated by receiving the control power Cnt from the outside to operate the switch pc2 installed in the potential line of the power supply line (+). The power supply operates the electronic switching device 400 through a trigger circuit, and in case of a short circuit, the switch pc2 installed in the potential line is turned off momentarily to protect the power electronic switching device 400 from a short circuit current. Structure.

Here, the trigger circuit may be composed of the trigger circuit 500 shown in FIG.

100: switching device 200: switching control unit
300: fault interruption holding unit 400: electronic switching device for power
410: contact status display unit 500: trigger circuit
510: start potential forming unit 520: gate control power supply
600: load 700: fault detection unit
800: remote control unit

Claims (8)

A trigger circuit for supplying control power to a gate of a power electronic switching element connected in series with a load on a power line.
The trigger circuit
A gate control power supply which is controlled on / off by a control power supply and protects the power electronic switching device from a short circuit current by instantaneous operation due to a voltage drop between lines in a short circuit of the power supply line;
And a start potential forming unit connected to the power electronic switch element to form a start potential required for self-maintenance of the gate control power supply unit and to maintain an off state of the power electronic switch element. Trigger circuit.
In the switching device for connecting a power electronic switching element in series with a load on a power line, supplying a control power to the gate of the power electronic switching element,
A gate control power supply which is controlled on / off by a control power supply and protects the power electronic switching device from a short circuit current by instantaneous operation due to a voltage drop between lines in a short circuit of the power supply line;
And a start potential forming unit connected to the power electronic switch element to form a start potential required for self-maintenance of the gate control power supply unit and to maintain an off state of the power electronic switch element. Switching device using a trigger circuit characterized in that.
The switching device using a trigger circuit according to claim 2, further comprising a fault interruption holding unit for determining whether or not to supply control power to the gate control power supply unit according to the state of the power supply line detected by the current transformer or the image current transformer. .
The trigger circuit of claim 2, further comprising a switching control unit configured to directly supply control power supplied from the outside to the gate control power supply unit or determine whether to supply the power according to the state of the power line detected by the current transformer. Switching device used.
The method of claim 2, wherein a bridge diode is connected in parallel through a power electronic switching element and a resistor, and a contact state display unit includes a contact state display unit in which a light emitting diode is connected in series through a resistor to a secondary side of the bridge diode. Switching device using trigger circuit. delete delete delete

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