KR20180096999A - Fault current limiting for DC grid type and the method thereof - Google Patents

Abstract

A fault current limiter for a DC grid according to the present invention is a fault current limiter provided between a converter for converting AC power into DC power and a DC power system to limit a fault current, A sensor for detecting a fault current according to a change; An IGBT switch provided on a main current path through which a steady-state current flows from the converter to a DC power system, and which interrupts a fault current by a switching operation when the sensor senses a fault current; The IGBT switch is connected in series, and after the fault current is firstly cut off from the IGBT switch, the main current path is cut off secondarily so that the fault current is bypassed to the current flow path, A switch module forming a reclosing path; A reverse voltage capacitor arranged in parallel with the main current path provided with the IGBT switch and the switch module to apply a reverse voltage to limit the fault current in the current flow path by the interrupting operation of the IGBT switch and the switch module; A surge arrestor disposed in parallel with the current flow path for discharging a fault current limited by the reverse voltage capacitor to prevent an overvoltage; And a controller for outputting a cut-off switching control signal of the IGBT switch and a cut-off switching control signal of the switch module and a switch-over switching control signal for forming a recloser when a fault current is sensed by the sensor.

Description

Technical Field The present invention relates to a fault current limiter for a DC grid,

The present invention relates to a fault current limiter for a DC grid and a control method thereof. More particularly, the present invention relates to a fault current limiter for a DC grid which can stably limit a fault current due to a high- And more particularly, to a fault current limiter for a DC grid and a control method thereof.

Recently, the DC grid HVDC (High Voltage Direct Current) transmission system specialized in long-distance high capacity transmission has been attracting attention as a core electric energy transmission line in the 21st century.

This DC grid transmission system can overcome the disadvantages that are limited to existing point-to-point power transmission, and it is possible to construct a grid network such as an AC power system, thereby enabling power exchange of paths combining various renewable energy sources, And improvement of power transmission stability.

Generally, in the case of a high voltage electric power field, a current zero point is naturally formed due to an alternating current-voltage characteristic, a breaker is opened at the time of an accident to end an instantaneous arc and a current zero point is formed We are proceeding with natural blockade through arc arc. However, in the case of a direct current system, a natural current zero point is not formed, so a current zero point must be formed artificially.

In the case of the commercialized DC circuit breaker, the arc is forced by the cooling and division of the arc generated in the machine. However, this is a possible application even at the low voltage of 1.5 kV, and it is impossible to apply it if the rated voltage increases due to the current DC transmission forecast. Therefore, there is a need for a method for artificially forming the zero point of the DC current. Many approaches are being discussed to implement this.

Among them, short-circuit current limiter is a device that improves the mechanical and thermal stress prevention and system reliability of electric power equipment by injecting high-speed impedance when a large fault current occurs in the power system and making the fault current less than the proper value.

Such superconducting current limiting techniques are typically composed of a resistive superconducting fault current limiter and a saturated iron core superconducting fault current limiter. This prior art has the advantage that it can be charged quickly to suppress the overcurrent due to a ground fault or a short circuit accident, which has a fatal influence on the power quality and stability of the power system by utilizing the characteristics peculiar to the superconductor.

FIG. 1 is a view schematically showing a configuration of a conventional hybrid circuit breaker. As shown in FIG. 1, the conventional circuit breaker is a hybrid type high voltage DC interrupter utilizing a large number of IGBTs for power semiconductor, and a large amount of IGBT switches capable of switching at a very high speed is used. And the reliability is lowered by the stable interception.

That is, in the case of the superconducting current-wave technique, there are two problems.

The first is that high cost is required and fabrication is not easy. A superconducting fault current limiter can result in higher costs, due to the cost of cooling and the volume required for superconductor construction, compared to conventional free-fall systems. Furthermore, the structure is complicated as compared with a current-limiting device that does not use a superconductor, so that it is not easy to manufacture.

The second is that it is not easy to coordinate and reclose. In the case of a superconducting fault current limiter, the impedance is almost zero at steady state, and it is a technology to effectively control and shutdown the fault current by instantaneously generating an impedance through the phenomenon of superconducting fault current fault at the accident. Therefore, the recovery of the cold current is essential for the recovery of the normal state, but the time required for the recovery of the superconducting fault current is usually from a few seconds to a minute, so it is not suitable for the protection cooperation and reclosing. In addition, since the superconducting fault current limiter has a large loss to be absorbed during the recovery time, it is essential to compensate for this.

Therefore, such a superconducting fault current limiter is a technology capable of quick input for suppressing an overcurrent due to a ground fault or short-circuit accident utilizing the characteristics unique to a superconductor, and is limited to the development of a current limiter for an alternating current system. However, the problems of the above-mentioned conventional technology, such as difficulty in cooperating and reclosing, difficulty in manufacturing, and difficulty in manufacturing, have been a problem to be solved for DC grid application.

Korean Patent Publication No. 10-2015-0020035

The present invention relates to a fault current limiter for a DC grid and a control method thereof, which can stably limit a fault current according to a high-power accident by applying a switching structure to a fault current limiter, And a method thereof.

According to an aspect of the present invention, there is provided a fault current limiter for a DC grid, the fault current limiter being provided between a converter for converting AC power into DC power and a DC power system to limit a fault current, A sensor for detecting a fault current according to a change in current of the DC power supplied to the inverter; An IGBT switch provided on a main current path through which a steady-state current flows from the converter to the DC power system, and which bypasses and bypasses a fault current by a switching operation; The IGBT switch is connected in series, and after the fault current is firstly cut off from the IGBT switch, the main current path is cut off secondarily so that the fault current is bypassed to the current flow path, A switch module forming a reclosing path; A reverse voltage capacitor arranged in parallel with the main current path provided with the IGBT switch and the switch module to apply a reverse voltage to limit the fault current in the current flow path by the interrupting operation of the IGBT switch and the switch module; A surge arrestor disposed in parallel with the current flow path for discharging a fault current limited by the reverse voltage capacitor to prevent an overvoltage; And a controller for outputting a cutoff switching control signal of the IGBT switch and a cutoff switching control signal of the switch module and a switching control signal for switching to a closed circuit.

The reactor further includes a reactor which is provided respectively at a rear end of the sensor and at a front end of the circuit breaker of the DC power system to reduce an increase rate of a fault current.

And a circuit breaker connected in series between the reactor and the DC power system for interrupting current supply to the DC power system when a zero point of a fault current is generated.

In particular, the present invention further includes a snubber capacitor connected in parallel with the IGBT switch to lower a transient voltage applied to the IGBT switch.

Particularly, the switch module is characterized in that any one of a piro actuator switch, a vacuum interrupter and an IGBT switch is applied.

In particular, the pyroactuator switch is constituted by a plurality of pyroelectric actuators, and is characterized in that it is sequentially switched every time a fault current is generated to form a recloser.

In particular, the controller outputs a control signal for shutting down the IGBT switch in an off state sequentially when a fault current is sensed from the sensor, and then outputs a control signal for shutting off the switch module, And a control signal is outputted so as to switch to the ON state.

In particular, in the case where the controller forms the reclosing after the breaker is turned on, the controller outputs a control signal to switch the switch module and the IGBT switch to the on state, and thereafter switches the breaker to the off state And is characterized in that it outputs a control signal.

A damping resistor connected in parallel to the reverse voltage capacitor to adjust a peak value of the charging voltage; A capacitor switch connected in parallel to the reverse voltage capacitor for switching to discharge the voltage of the capacitor; And a discharging resistor connected in series with the switch for discharging the current stably during discharging.

According to another aspect of the present invention, there is provided a method of controlling a fault current limiter for a DC grid, the method comprising the steps of: detecting a fault current according to a change in current of a DC power supplied from the converter to a DC power system; Blocking the IGBT switch provided in the main current path when the fault current is detected; Blocking the IGBT switch by a primary current path and then blocking the switch module connected in series with the IGBT switch to the main current path to bypass the fault current to the current path; Limiting a fault current bypassed by the current flow path by applying a reverse voltage by a reverse voltage capacitor; Discharging the limited fault current through a surge arrestor; When the fault current is zero, operating the breaker; And switching the IGBT switch and the switch module to an on state to form a recloser after the interrupting operation of the interrupter.

In particular, the method includes the step of arranging a reactor between the converter and the DC power system to reduce the rate of increase of the fault current.

In particular, a snubber capacitor is disposed in parallel with the IGBT switch to lower the transient voltage applied to the IGBT switch.

Particularly, the switch module is characterized in that a recloser is formed by applying any one of a piro actuator switch, a vacuum interrupter and an IGBT switch.

In particular, the pyroactuator switch is constituted by a plurality of pyroelectric actuators, and is characterized in that it is sequentially switched every time a fault current is generated to form a recloser.

In particular, in the step of forming the recloser, when the circuit breaker is turned on and then the recloser is formed again, the switch module and the IGBT switch are controlled to be turned on, and then the breaker is turned off Quot; state "

Here, the method includes the step of controlling on / off switching of the switch to discharge the voltage of the reverse voltage capacitor, in particular, by applying a reverse voltage of the reverse voltage capacitor.

In particular, in the step of applying the reverse voltage of the reverse voltage capacitor, a peak value of the voltage at the time of charging is adjusted by connecting a damping resistor in parallel to the reverse voltage capacitor.

In particular, in the step of applying a reverse voltage of the reverse voltage capacitor, a discharging resistor is connected in parallel to the reverse voltage capacitor to discharge the current stably during discharging.

According to the present invention, a switching structure is applied to the fault current limiter to stably limit a fault current due to a high-power accident and to form a recloser, thereby being stable and reducing maintenance cost.

In addition, by using a small amount of semiconductor elements, the conduction loss in the steady state can be minimized.

FIG. 1 is a view schematically showing a configuration of a conventional hybrid circuit breaker.
FIG. 2 is a view schematically showing a configuration of a high-voltage DC system to which the fault current limiter of the present invention is applied.
3 to 6 are diagrams schematically showing a configuration of a fault current limiter for a DC grid according to the first embodiment of the present invention and a current path change according to a transient state.
FIG. 7 to FIG. 10 are diagrams schematically showing a configuration of a fault current limiter for a DC grid according to a second embodiment of the present invention and a current path change according to a transient state. FIG.
11 shows current waveforms in the event of a fault current limiter for a DC grid according to the present invention;
12 is a graph showing transient current characteristics of each path of a fault current limiter for a DC grid according to the present invention;
13 is a graph showing transient characteristics of the reverse voltage capacitor voltage change of a fault current limiter for a DC grid according to the present invention.
14 is a graph showing transient characteristics of IGBT voltage changes of a fault current limiter for a DC grid according to the present invention;

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, numerals (e.g., first, second, etc.) used in the description of the present invention are merely an identifier for distinguishing one component from another.

Also, in this specification, when an element is referred to as being "connected" or "connected" with another element, the element may be directly connected or directly connected to the other element, It should be understood that, unless an opposite description is present, it may be connected or connected via another element in the middle.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a view schematically showing a configuration of a high-voltage DC system to which a fault current limiter according to the present invention is applied, FIGS. 3 to 6 show configurations of a fault current limiter for a DC grid according to a first embodiment of the present invention, FIGS. 7 to 10 schematically illustrate the current path change according to the configuration and transient state of the fault current limiter for the DC grid of the second embodiment according to the present invention. FIG. Fig.

2, the high voltage DC system includes a converter 21 for converting the high voltage AC power 20 into a DC voltage, a system impedance 22 for matching the RLC impedance of the converted DC power, A fault current limiter 23 for limiting the current when the current is generated, and a current breaker for blocking the fault current.

When a fault current occurs in the high voltage DC system, the fault current limiter stably limits the current.

The configuration of the fault current limiter of the present invention is as follows.

3 to 6, a fault current limiter for a DC grid according to the present invention includes a fault current limiter 100 provided between a converter for converting AC power into DC power and a DC power system to limit a fault current A switch 121, a switch module 130, an IGBT switch 140, a snubber capacitor 145, a reverse voltage capacitor 150, a damping resistor 152, a discharge resistor 154 A capacitor switch 156, a controller 160, a surge arrestor 170, and a circuit breaker 180. [ The fault current limiter 100 includes a main current path in a steady state and a current path and an absorption path connected in parallel with the main current path so that fault current can be bypassed to the current path in case of an accident.

The sensor 110 senses a fault current according to a change in current of DC power supplied to the DC power system. At this time, when the sensor 110 senses a sudden current change by using the current sensor, the controller 160 recognizes it and controls the current interruption according to the fault current.

The reactors 121 and 122 are provided at both ends of the sensor 110 and in front of the circuit breaker 180 of the DC power system so as to reduce the rate of increase of the fault current in both directions corresponding to the location where an accident occurs. That is, the reactors 121 and 122 are connected in series to the main current path so that di / dt is reduced so that the sensor 110 can measure the failure.

The IGBT switch 140 is provided on the main current path through which the steady-state current flows from the converter to the DC power system. In the steady state, since the current is passed through the switch like a normal conductor, the conduction loss can be minimized, The controller 160 performs a fast switching operation according to a control signal to block the fault current first. At this time, the IGBT switch 140 temporarily stops the fault current by fast switching operation.

The snubber capacitor 145 is connected in parallel with the IGBT switch 140 to lower the transient voltage applied to the IGBT switch 140. That is, the IGBT switch 140 is a protection capacitor for preventing damage due to a transient voltage momentarily applied to the IGBT switch 140.

The switch module 130 is connected in series to the front end of the IGBT switch 140. The switch module 130 cuts off the fault current of the IGBT switch 140 firstly and then cuts off the main current path secondarily, So that a reclosing of the main current path is formed by the switching switching operation.

More specifically, the switch module 130 may be one of a pyro-conductor switch (PCS), a vacuum interrupter, and an IGBT switch. Here, the switching module 130 has a structure capable of forming a recloser in place of the superconducting fault current limiter.

The vacuum interrupter is small, has high reliability, is excellent in open / close characteristics, and is easily used for maintenance, which is widely used in small to medium voltage and large capacity. In addition, by applying IBGT to the switch module, it is possible to apply a quick response cutoff and form a recloser.

That is, after the primary turn-off operation of the IGBT switch 140, it is possible to minimize the conduction loss by the IGBT switch through the secondary cut-off operation of the quick switch module.

The IGBT switch 140 and the switch module 130 are disposed in parallel with the main current path I ₃ and the IGBT switch 140 and the switch module 130 are interrupted A reverse voltage is applied to limit the fault current of the current-flow path I ₂ by the operation.

The surge arrestor 170 is disposed in an absorption path I ₁ connected in parallel with the current flow path I ₂ to discharge a fault current limited to the ground by the reverse voltage capacitor 150 . In other words, when a voltage exceeding a certain voltage is applied to the device, current flows to the ground to prevent damage.

More specifically, the surge arrestor 170 is disposed on the current absorption paths (I ₁₎ connected in parallel with the current-limiting path (I _2). The impedance of the surge arrestor 170 is greatly reduced as a voltage exceeding the threshold voltage is generated at both ends of the current absorption path I ₁ .

The surge arrester 170 flows a current to the ground at the moment when the surge arresters 170 exceed the threshold voltage to make the magnitude of the current 0 [A]. Then, the total current I _T of the fault current limiter 100 is forcibly set to 0 [A]. When the total current I _T of the fault current limiter 100 reaches 0 [A], the circuit breaker 180 opens the circuit to isolate the fault line from the dry circuit.

The damping resistor 152, the discharge resistor 154 and the capacitor switch 156 are connected in parallel with the reverse voltage capacitor 150 of the current flow path I ₂ .

The damping resistor 152 is connected in parallel to control the peak value of the charge voltage to suppress spikes of voltage and current.

The discharging resistor 154 stably discharges the current during the instantaneous discharge generated when the capacitor switch 156 is opened and closed, and discharges the capacitor.

The capacitor switch 156 is connected in parallel to the reverse voltage capacitor 150 to switch to discharge the voltage of the capacitor.

When the controller 110 senses a fault current in the sensor 110, the controller 160 outputs a cutoff switching control signal of the IGBT switch 140 and a cutoff switching control signal of the switch module 130 and a switching control signal .

More specifically, when a fault current is sensed by the sensor 110, the controller 160 sequentially outputs a control signal to turn off the IGBT switch 140, and then turns off the switch module 130 And outputs a control signal for switching the breaker to the ON state.

Also, when the magnitude of the current in the surge arrestor 170 becomes zero [A], the controller is turned off and completely shut off.

At this time, the controller 160 turns on the switch module 130 and the IGBT switch 140 when the circuit breaker is turned on and again forms the reclosing of the main current path I ₃ And outputs a control signal to switch the breaker to the off state. Here, the on / off state of the breaker means not the on / off state of the switch, but a state in which the breaker operates in accordance with the failure in the standby state. That is, the normally-closed circuit breaker operates to switch the switch to an off-state when the switch is in the ON-state connected to the switch or to an ON-state in the event of a failure.

The circuit breaker 180 is connected in series between the reactors 121 and 122 and the DC power system to completely cut off the current when a fault current is generated. Here, the circuit breaker 180 is completely disconnected through the fault current limiter of the fault current limiter, and the switch portion of the switch module 130 draws the normal switch to the line portion to prepare for reclosing.

7 to 10, the fault current limiter for the DC grid according to the second embodiment of the present invention is structurally the same as that of the first embodiment, and the switch module is constructed by applying a piro actuator switch Fig. Here, the description of the same portions as those of the first embodiment will be omitted.

The Pyro-Conductor Switch (PCS) 230 is a super high-speed mechanical switch, and a plurality of the Pyro-Conductor Switches (PCS) 230 are sequentially provided. Here, the pyroactuator is formed as a simple mechanical structure with a one-time mechanical switch, and it needs to be replaced after one operation, so that a plurality of the pyroactuators can be arranged and a reclosing mechanism can be formed through a switching mechanism (not shown).

Such pyroactuators are very small in size and low in cost, do not require external energy supply, and can operate at a very high speed (for example, 2 ms or less).

Therefore, the maintenance cost is remarkably low as compared with the structure using the conventional superconducting fault current limiter, and the high-speed mechanical switch can be replaced with the switching structure utilizing the low-cost pyroactuator switch, thereby realizing the reclosing function.

The operation of the fault current limiter for the DC grid of the first and second embodiments will be described. Hereinafter, the current path change according to the transient state of the fault current limiter for DC grid of the present invention will be described with reference to FIG. 3 to FIG.

3 and 7, a fault current limiter for a DC grid according to the present invention energizes a current through a main current circuit path when the power system is normally operated. Here, in the main current circuit path, a switch module and an IGBT switch that perform the same operation as a general conductor are constituted, so that conduction loss can be minimized because electric current is supplied.

In addition, suppression reactors are connected in series in the main current circuit path to suppress the rate of current rise (di / dt). This suppression reactor serves to reduce the rising speed of the fault current generated in the accident, and reactor components remain in the main current path even during normal operation.

On the other hand, when an accident occurs, the fault current limiter senses the fault current according to the current change of the DC power supplied from the converter to the DC power system. That is, a fault current having a high current rise rate (di / dt) is sensed through a sensor.

4 and 8, when the fault current is sensed, the IGBT switch provided in the main current path is firstly interrupted. At this time, the IGBT switch serves to bypass current by fast operation and shutdown.

Next, as shown in FIGS. 5 and 9, after the IGBT switch is firstly cut off, the switch module connected in series with the IGBT switch is cut off in the main current path to bypass the fault current to the current path. Here, after the operation of the IGBT switch, the main current path is completely cut off through the quick operation of the switch module. At this time, the voltage to be handled by the IGBT switch is reduced, and the number of IGBT switches can be minimized. This minimization of the number of IGBT switches can minimize the conduction loss in the steady state.

By arranging the snubber capacitor in parallel with the IGBT switch, the transient voltage of the IGBT switch element can be reduced.

Then, after the main current path I ₃ is shut off, the bypass current flows through the commutation path I ₂ and the fault current is suppressed by the reverse voltage capacitor 150. The limited fault current through the current limiting operation ultimately opens the breaker 180 to complete the shutdown operation.

The IGBT switch 140 and the switch module 130 are disposed in parallel with the main current path I ₃ provided with the IGBT switch 140 and the switch module 130, 130) of the reverse voltage is applied to limit the fault current of the current-limiting path (I ₂₎ by the breaking operation.

The surge arrestor 170 is disposed in an absorption path I ₁ connected in parallel with the current flow path I ₂ to flow a limited fault current to the ground by the reverse voltage capacitor 150, .

The damping resistor 152 is connected in parallel to adjust the peak value of the charging voltage to suppress spikes of voltage and current. The discharging resistor 154 is connected to the discharging resistor 152, It discharges the current of the battery stably and absorbs the overvoltage and protects the circuit. At this time, the capacitor switch 156 is connected in parallel to the reverse voltage capacitor 150 to switch off the voltage of the capacitor.

Then, as shown in FIGS. 6 and 10, after the breaker is shut off, the IGBT switch and the switch module are turned on to form a recloser. Here, when the recloser is formed, the switch module 130 and the IGBT switches 140 and 240 are controlled to be turned on when the circuit breaker is turned on and then the recloser is formed again And then controls the breakers 180 and 280 to be turned off. That is, the switch modules 130 and 230 and the IGBT switches 140 and 240 and the DC breakers 180 and 280 are also closed for normal operation of the power circuit main circuit of the reclosing main circuit.

More specifically, as the switch module 130, a recloser is formed by applying any one of a piro actuator switch, a vacuum interrupter, and an IGBT switch. In this case, as shown in FIG. 12, when the piro actuator switch 230 is applied to the switch module, a plurality of switch modules are sequentially switched each time a fault current is generated to form a recloser.

The Pyro-Conductor Switch (PCS) 230 is a super high-speed mechanical switch, and a plurality of the Pyro-Conductor Switches (PCS) 230 are sequentially provided. Here, the pyroactuator is formed as a simple mechanical structure with a one-time mechanical switch, and it needs to be replaced after one operation, and a plurality of the pyroactuators can be disposed to form a reclosing mechanism through a switching mechanism (not shown).

12 is a graph showing the transient current characteristics of each path of the fault current limiter for a DC grid according to the present invention. FIG. 11 is a graph showing current waveforms of a fault current limiter for a DC grid according to the present invention, FIG. 13 is a graph showing transient characteristics of the reverse voltage capacitor voltage change of the fault current limiter for a DC grid according to the present invention, and FIG. 14 is a graph showing the IGBT voltage Fig. 3 is a graph showing the transient characteristics of the change. Fig.

As shown in Figs. 11 and 12, when the expected short-circuit current is 82 (kA) in current and voltage waveforms at the time of the accident, and the fault limiting current is 4 kA, the operation time of the IGBT switch is 200 이고, The operation time of the actuator switch is 1.5 ms and the IGBT is 1, the reverse voltage capacitor is 1250 (㎌), the inductor is 7.4 mH, and the time limit in case of failure is 3 ms. Therefore, it can be seen that the fault current is limited by the fast operation characteristic by the IGBT switch and the piro actuator switch.

As shown in FIG. 13, the change in the magnitude of the charge voltage with time of the reverse voltage capacitor is shown. It takes 55 ms from the beginning to the charge peak value, and the voltage value is stabilized after the peak value.

As shown in FIG. 14, the voltage applied to the IGBT is shown to show a change in the voltage applied to the IGBT and a voltage change with respect to the quick response due to the switching of the IGBT.

Therefore, the present invention can realize a reclosing function by replacing the conventional superconducting fault current limiter with a low-cost switching structure by applying a very high-speed mechanical switch.

The scope of the present invention is not limited to the above-described embodiments, but may be embodied in various forms of embodiments within the scope of the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

110, 210 --- Sensor
121, 122, 221, 222 --- Reactor
130, 230 --- Switch module
140, 240 --- IGBT switch
145, 245 --- Snubber Capacitor
150, 250 --- Reverse voltage capacitor
152, 252 --- Damping Resistance
154, 254 --- discharge resistance
156, 256 --- Capacitor switch
160, 260 --- Controller
170, 270 --- surge arrester
180, 280 --- Breaker

Claims (18)

In a fault current limiter provided between a converter for converting AC power into DC power and a DC power system to limit the fault current,
A sensor for detecting a fault current according to a change in current of the DC power supplied to the DC power system;
An IGBT switch provided on a main current path through which a steady-state current flows from the converter to a DC power system, and which interrupts a fault current by a switching operation when the sensor senses a fault current;
The IGBT switch is connected in series, and after the fault current is firstly cut off from the IGBT switch, the main current path is cut off secondarily so that the fault current is bypassed to the current flow path, A switch module forming a reclosing path;
A reverse voltage capacitor arranged in parallel with the main current path provided with the IGBT switch and the switch module to apply a reverse voltage to limit the fault current in the current flow path by the interrupting operation of the IGBT switch and the switch module;
A surge arrestor disposed in parallel with the current flow path for discharging a fault current limited by the capacitor to prevent an overvoltage; And
And a controller for outputting a cutoff switching control signal of the IGBT switch and a cutoff switching control signal of the switch module and a switching switching control signal for forming a recloser when a fault current is detected in the sensor.
The method according to claim 1,
Further comprising a reactor provided at a rear end of the sensor and at a front end of the circuit breaker of the DC power system to reduce an increase rate of a fault current.
3. The method of claim 2,
And a circuit breaker connected in series between the reactor and the DC power system to cut off the current supply of the DC power system when a zero point of a fault current occurs.
The method according to claim 1,
Further comprising a snubber capacitor connected in parallel with the IGBT switch to reduce a transient voltage applied to the IGBT switch.
The method according to claim 1,
Wherein the switch module is one of a piroactuator switch, a vacuum interrupter, and an IGBT switch.
6. The method of claim 5,
Wherein the pyroactor switch comprises a plurality of pyroelectric actuator switches and is sequentially switched each time a fault current is generated to form a recloser.
The method according to claim 1,
Wherein the controller outputs a control signal for sequentially turning off the IGBT switch when the fault current is sensed by the sensor, and then outputs a control signal for turning off the switch module to turn off the breaker, And outputs a control signal to switch the DC grid.
The method according to claim 1,
The controller outputs a control signal to switch the switch module and the IGBT switch to an on state and then outputs a control signal to switch the breaker to the off state when the breaker is turned on again and forms a reclosing again And outputs the output current to the DC grid.
The method according to claim 1,
A damping resistor connected in parallel with the reverse voltage capacitor to adjust a peak value of the charging voltage;
A crosstalk switch connected in parallel to the reverse voltage capacitor for switching to discharge the voltage of the capacitor; And
And a discharging resistor connected in series with the switch for discharging a current stably during discharging.
Detecting a fault current according to a change in current of a DC power supplied from the converter to the DC power system;
Blocking the IGBT switch provided in the main current path when the fault current is detected;
Blocking the switch module connected to the IGBT switch in the main current path by bypassing the IGBT switch by bypassing the IGBT switch;
Limiting a fault current bypassed by the current flow path by applying a reverse voltage by a reverse voltage capacitor;
Discharging the limited fault current through a surge arrestor;
When the fault current is zero, operating the breaker; And
And switching the IGBT switch and the switch module to an on state to form a recloser after the circuit breaker is disconnected.
11. The method of claim 10,
And placing a reactor between the converter and the DC power system to reduce the rate of increase of the fault current.
11. The method of claim 10,
Wherein a snubber capacitor is disposed in parallel with the IGBT switch to reduce a transient voltage applied to the IGBT switch.
11. The method of claim 10,
Wherein the switch module forms a recloser by applying one of a piro actuator switch, a vacuum interrupter and an IGBT switch.
14. The method of claim 13,
Wherein the pyroactuator switch comprises a plurality of pyroelectric actuator switches and is sequentially switched each time a fault current is generated to form a recloser.
14. The method of claim 13,
In the step of forming the reclosing,
And controls to switch the switch module and the IGBT switch to the ON state and then to switch the circuit breaker to the OFF state when the circuit breaker is switched to the ON state and then forms the reclosing again. A method for controlling a fault current limiter.
11. The method of claim 10,
In the step of applying the reverse voltage of the reverse voltage capacitor,
And controlling on / off switching of the switch to discharge the voltage of the reverse voltage capacitor.
11. The method of claim 10,
In the step of applying the reverse voltage of the reverse voltage capacitor,
And a damping resistor is connected in parallel to the reverse voltage capacitor to adjust a peak value of the voltage during charging.
11. The method of claim 10,
In the step of applying the reverse voltage of the reverse voltage capacitor,
And a discharging resistor is connected in parallel to the reverse voltage capacitor to discharge the current stably during discharging.

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