KR20140003810A - Cabinet panel of built-in neutral line repair function and control method thereof - Google Patents

Abstract

The present invention relates to a distributing board with neutral line recovery capability preventing the occurrence of over-voltage and maintaining normal voltage when the disconnection of a neutral line (N) occurs in the distributing board, and attenuating excessive image harmonic waves generated from the neutral line, and to a method controlling the same. The distributing board with neutral line recovery capability comprises: a power supply device equipped with a main breaker and a breaker for supplying power; and a neutral line recovery device interconnected with the power supply device, detecting the disconnection of the neutral line mounted on the power supply device, and connecting one end of the inductance to a neutral line for recovery to recover the neutral line, to prevent the voltage from generating and to maintain normal voltage. [Reference numerals] (210) Break detector; (220) Current detector; (230) Controller; (240) Neutral image recovery period and harmonic reduction; (250) Alarm generator; (260) Alarm reset signal input

Description

Cabinet panel of built-in neutral line repair function and control method

The present invention relates to a distribution panel with a neutral line recovery function and a control method thereof, and more particularly, to prevent overvoltage and maintain a normal voltage when a neutral line (N) disconnection occurs in the distribution panel. The present invention relates to a distribution panel equipped with a neutral line recovery function capable of attenuating excessive image harmonics generated from a neutral line, and a control method thereof.

In general, the cabinet panel is equipped with an image harmonic filter for removing image harmonics.

Harmonics are frequencies that are integer multiples, such as 2, 3, and 4 times the fundamental frequency, and are called distortion or distortion waves, and especially high frequency orders such as 3, 6, 9, etc. The high frequency component corresponding to the multiple of 3 is called image harmonic.

Due to the characteristics of the distribution system in Korea, which adopts three-phase four-wire system, unbalanced current flows in the neutral wire due to the mixing of single-phase and three-phase loads.In recent years, computers, LED lighting devices, copiers, office equipment, uninterruptible power supply More image harmonics flow through the neutral due to the increase in nonlinear loads such as UPS. Since the phase harmonics of three phases have in-phase values, up to three times the image harmonics flow by being superimposed on a neutral line as if three single-phase power sources are connected in parallel. When excessive image harmonics flow in the neutral line, it causes obstacles such as overheating of the neutral conductor, deterioration of the distribution transformer, voltage distortion, communication line noise, and malfunction of electrical and electronic equipment.

Therefore, various methods have been proposed in the distribution panel to attenuate such excessive image harmonics. Among them, three image lines are used to reduce the image impedance by using a zigzag connection transformer (zig-zag transformer) connected to three phase lines and a neutral line. A typical device is to prevent the image harmonics from the neutral line to the load system and to absorb the image harmonics by absorbing it to the zigzag connection transformer. As described above, the image harmonic filter using the zigzag connection transformer can efficiently attenuate the third-order harmonics, which are the most generated orders.

Conventional technology for a distribution panel using an image harmonic filter using a zigzag connection transformer is disclosed in Korean Patent Application Publication No. 10-0795037 (Invention: Image Harmonic Reduction Device with Overload Protection Function) (hereinafter, " Prior art 1 ") and Korea Patent Office Patent Publication No. 10-0849463 (name of the invention: image harmonic reduction device equipped with an overload protection device) (hereinafter referred to as" prior art 2 ") It is.

In the disclosed prior art 1, a plurality of circuit breakers are connected to the distribution panel, and three phases (A, B, C) of the power supply and the neutral wire (N) pass through the distribution panel breaker, and each phase line (A, B, C) and the neutral wire (N), but the neutral wire (N) through a cutoff switch, the circuit is cut off when the connection transformer rises above a certain set temperature, and again the temperature of the connection transformer is lowered below a certain temperature It operates to provide overload protection that automatically restores the ground circuit.

In addition, the disclosed prior art 2 includes a three-phase line R (R, S, T) which is connected to three-phase lines R, S, T and a neutral line N of a power source passing through the entire distribution, , S, T), and a coil constituting the electromagnetic contactor is connected to a temperature switch incorporated in the image harmonic reduction device, and the three-phase line R , S, T) of the electromagnetic contactor is opened and closed.

The conventional technology 2 configured as described above includes a temperature switch inside the image harmonic reducing device, and connects an input terminal of the three-phase lines R, S, and T introduced into the reducing device to an electromagnetic contactor connected to the temperature switch, thereby reducing the inside of the reducing device. When the temperature rises or falls below a certain temperature, the temperature switch is turned on / off accordingly to open or connect the switch of the magnetic contactor connected to the three-phase wires R, S, and T. It can be isolated or energized to prevent burnout of the abatement device due to overload and to operate the whole system stably without opening and closing of the neutral wire.

Registered Patent Publication No. 10-0795037 (Invention name: Image Harmonic Reduction Device with Overload Protection) 2. Registered Patent Publication No. 10-0849463 of Korea Patent Office (Invention name: Image Harmonic Reduction Device equipped with overload protection device)

However, although the conventional techniques as described above can reduce the image harmonics flowing to the neutral line to some extent, when the neutral wire is disconnected due to the image harmonics or overheating, the countermeasure against the neutral wire disconnection is not taken at all, so the overvoltage It caused a problem that the load device was burned out.

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art,

The problem to be solved by the present invention is to recover the neutral line to prevent the occurrence of overvoltage and to maintain the normal voltage when the neutral line (N) disconnection occurs in the distribution, and to attenuate the excessive image harmonics generated in the neutral line It is to provide a distribution board with a function and a control method thereof.

Another problem to be solved by the present invention is a distribution board equipped with a neutral line recovery function that detects the current flowing in the neutral line, and operates the jig-zag transformer when excessive current (over the reference value) flows to reduce the image harmonics To provide a control method.

Another problem to be solved by the present invention is to detect the neutral wire disconnection, when the neutral wire disconnection is detected, the neutral wire recovery function to recover the neutral wire to prevent overvoltage caused by the neutral wire disconnection and to maintain a steady voltage It is to provide the overall and its control method.

Distribution board with neutral wire recovery function according to the present invention for solving the above problems,

In the whole distribution,

A power supply having a main breaker and a distribution breaker;

In connection with the power supply device, and detect the disconnection of the neutral wire provided in the power supply device, if the disconnection of the neutral wire is detected, one end of the inductance is connected to the recovery neutral wire to prevent the occurrence of overvoltage through the neutral wire recovery and the normal voltage It characterized in that it comprises a neutral line recovery device for maintaining.

Neutral recovery device in the above,

A current detector for detecting a current flowing in the neutral line;

A disconnection detector measuring the neutral voltage and the ground voltage and outputting a disconnection detection value to neutral disconnection when the neutral voltage and the ground voltage are detected;

A controller for generating control signals for image harmonic reduction and neutral line recovery according to the current detection value and the disconnection detection value output by the current detector and the disconnection detector;

And an image harmonic reduction and neutral line recovery device for reducing the image harmonics flowing to the neutral line or restoring the neutral line according to the control signal generated by the controller to maintain the equilibrium of the single phase voltage.

In the above controller,

The current value detected by the current detector is compared with the reference set value, and when the detected current value exceeds the reference set value, it is determined that the image harmonics have risen, and a control signal for reducing the image harmonics is generated. .

The image harmonic reduction and neutral line recoverer,

A first switch operating according to a control signal for reducing image harmonics;

A zig-zag transformer that operates during the operation of the first switch to reduce an electric current flowing through a neutral line to remove image harmonics;

It characterized in that it comprises a second switch for maintaining the balance of the single-phase voltage by connecting each phase and the recovery neutral (N).

In addition, the distribution board control method with a neutral wire recovery function according to the present invention,

In the method for reducing the image harmonics and recovering them in the case of neutral disconnection,

(a) detecting current flowing through the neutral line when power is supplied;

(b) comparing the detected current with a reference set value to determine whether image harmonics increase, and when the image harmonics increase, operating the zig-zag transformer to reduce image harmonics;

(c) determining whether an image harmonic is increased by detecting a current flowing in a neutral line after the jig-zag transformer operation, and operating the circuit breaker when the image harmonic is not reduced;

(d) detecting whether the neutral wire is disconnected by detecting the neutral wire and the ground voltage;

(e) if it is determined that the disconnection of the neutral wire is detected, operating a neutral wire restorer to recover the disconnected neutral wire;

(f) checking whether the neutral line is normally restored after the neutral line recovering operation, and operating a breaker when the neutral line is not normally restored;

(g) generating an alarm for neutral wire disconnection after the breaker operation or after the image harmonics are normally reduced or after the neutral wire is normally restored;

(h) if the alarm release request is generated after the alarm is generated, comprising the step of releasing the generated alarm.

According to the present invention, even when a neutral line (N) disconnection occurs in the distribution panel, there is an advantage of preventing the occurrence of overvoltage and maintaining a normal voltage.

In addition, according to the present invention, when the image harmonics increase by detecting a current flowing in the neutral line, the jig-zag transformer may be operated to attenuate the image harmonics flowing in the neutral line.

1 is a block diagram of a distribution board equipped with a neutral wire recovery function according to the present invention,
2 is a circuit diagram of an embodiment of the image harmonic reduction and neutral line recoverer of FIG.
Figure 3 is a flow chart illustrating a control method of the distribution panel with a neutral wire recovery function according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

1 is a circuit diagram of a distribution board having a neutral line recovery function according to a preferred embodiment of the present invention, a power supply device 100 including a main breaker 101 and a distribution breaker (MCCB) and a neutral line recovery device ( 200).

Here, the power supply device 100 is supplied with power through a three-phase four-wire type (R, S, T, N), and detailed operation of the main breaker 101 or the switchboard breaker (MCCB) included therein is a general distribution. Since it is the same as the operation of the first half, the detailed description of this part will be omitted below.

The neutral recovery device 200 reduces the image harmonics by operating a zig-zag transformer when excessive current flows in the neutral wire N provided in the power supply device 100, and detects disconnection of the neutral wire. When disconnection is detected, one end of the inductance is connected to the recovery neutral to prevent the occurrence of overvoltage and maintain the normal voltage through the recovery of the neutral, thereby preventing the load connected to the single-phase power from being burned out.

The neutral line recovery device 200 includes: a current detector 220 for detecting a current flowing through the neutral line; A disconnection detector (210) for detecting whether the neutral is disconnected; A controller 230 generating control signals for reducing image harmonics and restoring neutral lines according to the current detection value and the disconnection detection value output by the current detector 220 and the disconnection detector 210; It includes an image harmonic reduction and neutral line recovery unit 240 to reduce the image harmonics flowing to the neutral line or to restore the neutral line in accordance with the control signal generated by the controller 230 to maintain the balance of the single-phase voltage.

In addition, the neutral wire recovery device 200 preferably further includes an alarm generator 250 for alarming the disconnection of the neutral wire according to the alarm generation control signal output by the controller 230.

In addition, the neutral line recovery device 200 generates an alarm release signal and transmits it to the controller 230 when an alarm release switch for alarm release is operated by an administrator after an alarm is generated by the alarm generator 250. Preferably, the alarm cancellation signal input unit 260 is further included. The alarm release signal input unit 260 is provided with an alarm release switch as is well known. Here, the controller 230 may automatically cut off the single-phase power supplied to the load if the alarm release request does not occur within a predetermined time after the alarm occurs. For this purpose, the single-phase power circuit breaker is supplied to the input terminal to which the single-phase power is supplied. It is preferable to have a.

The disconnection detector 210 measures the neutral voltage and the ground voltage, and when the neutral voltage and the ground voltage are detected, outputs a disconnection detection value through neutral disconnection and transmits the detected disconnection value to the controller 230.

In addition, the controller 230 compares the current value detected by the current detector 220 with a reference set value, and when the detected current value exceeds the reference set value, determines that image harmonics have risen and reduces image harmonics. Generates a control signal for and transmits to the image harmonic reduction and neutral recovery unit 240.

Here, the controller 230 stores a controllable program, and may be a microcomputer, a microprocessor, a central processing unit, a microcontroller, etc., which may control the overall operation of the image harmonic reduction and neutral line recovery device 200 according to the stored program. It is desirable to implement.

On the other hand, the image harmonic reduction and neutral line recovery unit 240, as shown in Figure 2, the first switch (M1) that operates in accordance with a control signal for reducing image harmonics; A zig-zag transformer (L1 to L6) which operates during the operation of the first switch (M1) to reduce the current flowing through the neutral line to remove image harmonics; It includes a second switch (M2) for connecting each phase (R, S, T) and the recovery neutral (N) to maintain the balance of the single-phase voltage.

In the distribution panel equipped with the neutral wire recovery function according to the present invention configured as described above, the power supplied from KEPCO is supplied through a primary transformer, and then, three-phase four-wire power is supplied through a Y-connection system.

At this time, excessive harmonics in the neutral lead to overheating of the neutral conductor, performance degradation of the distribution transformer, voltage distortion, communication line noise, and malfunction of electrical and electronic equipment.If the neutral is disconnected, the voltage supplied to each phase It depends on the capacity of the load, which causes the load device to burn out due to an abnormal voltage (overvoltage) at the light load side.

In order to prevent such an accident in advance in the present invention, the neutral line recovery device 200 detects the state of the neutral line at all times, and when the image harmonics are excessively flowed in the neutral line or the disconnection of the neutral line is immediately detected, the image harmonics are simultaneously reduced. By restoring to a neutral or other neutral, it compensates for the voltage imbalance between phases and prevents overvoltage from flowing to the light load side, so that a stable voltage is always maintained.

In more detail, when power is supplied to the distribution board, the current detector 220 detects a current flowing in the neutral wire and transmits a current detection value to the controller 230. In this case, it is preferable to use a general CT as the current detection method.

The controller 230 compares the detected current detection value with a preset reference set value (reference current value) to determine the amount of image harmonics. If the current detection value is equal to or less than the reference set value, the image harmonic is not excessive. If the current detection value is greater than the reference set value, it is judged that the image harmonics are excessively flowing in the neutral line, and the image harmonics decrease and the image harmonic reduction in the neutral line recoverer 240 is determined. Delivers control signals for

As shown in FIG. 2, when the control signal for reducing image harmonics is transmitted from the controller 230, the image harmonic reduction and neutral recovery unit 240 operates with the first switch M1 turned on. The primary inductance (L1 ~ L3) connected to the phase is connected to the secondary inductance (L4 ~ L6) in a zigzag manner to form a zig-zag transformer, and the image harmonics flowing in the neutral line by the zig-zag transformer Reduced. Here, the operation of the zig-zag transformer is disclosed in detail in the prior art document described in the technology that is the background of the invention, and it is obvious to anyone skilled in the art. Is omitted.

Through this process, excessive image harmonics flowing in the neutral line are reduced, and then the controller 230 continuously compares the current detection value detected by the current detector 220 with the reference set value, when the current detection value is smaller than the reference set value. It is determined that the image harmonics flowing in the neutral line is reduced, and the jig-zag transformer is released by operating the first switch M1 provided in the image harmonic reduction and the neutral line recoverer 240 in an off state.

Meanwhile, the disconnection detector 210 operates to detect whether the neutral line N is disconnected, and transmits the detected disconnection detection value to the controller 230.

For example, the disconnection detector 210 determines the disconnection of the neutral by measuring the voltage and / or the ground voltage of the neutral and confirming whether the neutral or the ground voltage is detected.

If it is determined that the neutral wire is disconnected, the neutral wire disconnection information is included in the neutral wire detection value and provided to the controller 230. Here, the neutral disconnection fault information may be referred to as a high signal (5V), and when the disconnection of the neutral wire is not detected, the neutral disconnection detection value may be referred to as a low signal (0V).

The controller 230 analyzes the disconnection detection value provided from the disconnection detector 210 by using a built-in control program, and when it is determined that the disconnection is not the neutral disconnection, the image harmonic reduction and the neutral recoverer 240 do not operate. Otherwise, if it is determined that the neutral is disconnected, the control signal for reducing the harmonics of the image and the neutral recovery is generated in the neutral recovery unit 240.

As shown in FIG. 2, the image harmonic reduction and neutral line recovery unit 240 includes a neutral line N for recovery internally, and when a control signal for neutral line recovery is transmitted by the controller 230, a second signal is generated. The switch M2 operates to connect the recovery neutral wire N and the coils (inductance) L1 to L3 for each phase. That is, the recovery neutral line (N) is to always recover the disconnected neutral wire by connecting the three phases to the recovery neutral wire in the case of neutral disconnection in the state that is always present. Here, the neutral wire connection can be easily connected by using a magnet switch or the like.

By reducing the image harmonics and recovering the disconnected neutral by operating the neutral recovery device 240, it is possible to maintain the unbalance of the single-phase voltage of each phase that may be caused by the disconnection of the neutral, as in the previous state. Even if the neutral wire of the 100 is disconnected, the overvoltage is prevented from flowing to the light load side and maintains the normal voltage as in the prior art, thereby preventing the problem that the overvoltage flows and burns the electric equipment as before.

On the other hand, if it is known that the controller 230 is determined to be the disconnection of the neutral wire will immediately drive the alarm generator 250. The alarm generator 250 operates to alert the disconnection of the neutral wire. In the present invention, the alarm is generated using a visual alarm and / or an audio alarm method.

If the administrator recognizes this in the presence of a visual or auditory alarm, he / she will follow up promptly, thereby preventing various accidents that may occur due to disconnection of the neutral line.

In addition, the administrator can release the alarms as needed. For example, when the alarm release switch provided in the alarm release signal input unit 260 is operated, the alarm release signal input unit 260 generates an alarm release signal and transmits it to the controller 230.

When the alarm release signal is transmitted, the controller 230 stops the operation of the alarm generator 250 to release the alarm.

In addition, the present invention, after performing the alarm for the disconnection of the neutral wire, if the alarm is not requested to be released within a predetermined time period automatically cuts off the power (single phase power) supplied to the load, the accident that may occur due to the neutral disconnection This is prevented in advance. Although not shown in the drawing, it is assumed that a power breaker is provided at the input terminal of the single-phase power.

In addition, the present invention, as it is well known, neutral harmonics are continuously detected through the disconnection detector 210 while the image harmonics are reduced and the neutral recovery unit 240 is operated by the neutral disconnection. If the voltage harmonic is detected despite the operation of the image harmonic reduction and the neutral recovery device 240, the controller 230 automatically operates the main circuit breaker 101 or cuts off the single-phase load power using a control signal. Therefore, the main breaker and the single-phase load power are cut off at the same time to prevent the load device from being burned out.

3 is a flowchart illustrating a distribution panel control method having a neutral line recovery function according to an exemplary embodiment of the present invention, and shows a process performed by the controller 230 of the distribution panel as shown in FIG. 1.

As shown therein, (a) detecting electric current flowing through the neutral line when power is supplied (S101 to S103); (b) comparing the detected current with a reference set value to determine whether image harmonics increase, and when the image harmonics increase, operating the jig-zag transformer to reduce image harmonics (S105 to S107); (c) detecting whether an image harmonic is increased by detecting a current flowing in a neutral line after the jig-zag transformer operation, and operating the circuit breaker when the image harmonic is not reduced (S121 to S123); (d) detecting whether the neutral line is disconnected by detecting the neutral line and the ground voltage (S109); (e) if it is determined that the disconnection of the neutral wire is detected, operating a neutral recovery device to recover the disconnected neutral wire (S111 to S113); (f) checking whether the neutral wire is normally restored after the neutral wire restorer is operated, and operating a breaker when the neutral wire is not normally restored (S125 to S127); (g) generating an alarm for neutral disconnection after the breaker operation or after the image harmonics are normally reduced or after the neutral line is normally restored (S115); (h) If an alarm release request is generated after the alarm is generated, step S117 to S119 is performed to release the generated alarm.

In the distribution panel control method equipped with the neutral wire recovery function according to the present invention, when power is first supplied to the distribution panel through the three-phase four-wire system in step S101, the current flowing through the neutral line through the current detector is measured in step S103. Will be detected. Thereafter, the detected current value is compared with a preset reference set value to determine the amount of image harmonics, and when the detected current value is larger than the reference set value, it is determined that the image harmonics are excessively flowing in the neutral line and the jig-zag By operating the transformer to reduce the image harmonics flowing in the neutral line (S105 ~ S107).

In addition, after operating the zig-zag transformer as described above, go to step S121 to check whether the image harmonics are normally reduced. That is, after operating the zig-zag transformer, the current flowing through the neutral line is detected again and compared with the preset reference set value. When the detected current value is larger than the reference set value, it is determined that the image harmonics are not normally reduced. In order to prevent a fire or the like from occurring due to the increase of the image harmonics, the breaker operation control signal is automatically generated (S123). The breaker operation control signal generated as described above is transmitted to each breaker (LBS, AISS, MCCB, etc.) to perform a power interruption operation.

After generating the circuit breaker operation control signal, go to step S115 to drive the alarm generator 250 to generate an alarm for an image harmonic increase visually and visually, and when the alarm generated by the administrator is requested to release the alarm generator 250. ) Is stopped to release the generated alarm (S115 to S119).

In addition, when the image harmonics are normally reduced after the jig-zag transformer is operated after the increase of the image harmonics, the alarm generator 250 is moved to step S115 to generate an alarm for the increase of the image harmonics visually. After the alarm is issued by the administrator is requested to stop the operation of the alarm generator 250, it is to release the generated alarm (S115 ~ S119).

For example, if the image harmonics are normally decreased after operating the jig-zag transformer after increasing the image harmonics, only the alarm for the image harmonics is increased. It will generate an alarm for the increase in image harmonics.

On the other hand, if the image harmonics do not flow excessively to the neutral line, the flow advances to step S109 to detect whether the neutral wire is disconnected through the disconnection detector. Here, since the detection of the disconnection of the neutral wire is detected in the same way as the operation of the distribution board with the neutral recovery, the detailed description is omitted in order to avoid duplicated materials.

When it is determined that the neutral wire is disconnected as a result of checking whether the neutral wire is disconnected (S111), the neutral wire restorer 230 is driven to recover the disconnected neutral wire (S113). For example, if a neutral wire is provided separately and the neutral wire (N) of the power supply line is disconnected, one end of the inductance is connected to the neutral wire to restore the neutral wire, thereby achieving phase voltage balance to prevent generation of overvoltage that may occur from the neutral wire disconnection, Maintaining the nominal voltage prevents the control line from working, preventing the connection load (eg drain pump, fire hydrant, elevator, etc.) from becoming paralyzed.

After operating the neutral wire restorer, go to step S125 to check whether the neutral wire is normally restored. If the neutral wire is not restored normally, that is, the neutral wire is detected again through the disconnection detector to detect the neutral wire. When it is detected, the control unit 100 moves to step S127 to automatically generate a breaker operation control signal in order to prevent various problems caused by the disconnection of the neutral wire (S127). The breaker operation control signal generated as described above is transmitted to each breaker (LBS, AISS, MCCB, etc.) to perform a power interruption operation.

After generating the circuit breaker operation control signal, the control unit moves to step S115 to drive the alarm generator 250 to generate an alarm for neutral wire disconnection in an audiovisual manner, and when the alarm generated by the administrator is requested to be released, the alarm generator 250. The driving of the vehicle is stopped and the generated alarm is released (S115 to S119).

In addition, if the neutral wire is normally restored after the neutral wire restorer is operated with the neutral wire break, go to step S115 to drive the alarm generator 250 to generate an alarm for the neutral wire break in audio and visual, and then the alarm generated by the administrator. If the release of the request is to stop the driving of the alarm generator 250, it is to release the generated alarm (S115 ~ S119).

For example, if the neutral wire is normally restored after the disconnection of the neutral wire, only the alarm for the neutral wire is generated, and if the neutral wire is not restored normally after the neutral wire, the breaker is operated to generate an alarm for the neutral wire.

According to the present invention, when the neutral wire of the power supply is disconnected in the distribution panel, the automatic recovery to the neutral wire for recovery is automatically performed to prevent phase voltage unbalance caused by the disconnection of the neutral wire, so that the electric load on the light load side is burned out. Will be prevented. In addition, if a disconnection occurs, an alarm is generated immediately so that the administrator can be aware of it, and afterwards, the administrator can quickly take follow-up actions, thereby preventing an accident such as a system failure that may occur later due to the disconnection. will be.

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 invention as defined in the appended claims and their equivalents. Of course, such modifications are within the scope of the claims.

100... Power supply
200 ... Image Harmonic Reduction and Neutral Repair
210... Disconnection detector
220 ... Current detector
230 ... Controller
240 ... Image Harmonic Reduction and Neutral Restorer

Claims (5)

In the first half of the distribution,
A power supply having a main breaker and a distribution breaker;
In connection with the power supply device, and detect the disconnection of the neutral wire provided in the power supply device, if the disconnection of the neutral wire is detected, one end of the inductance is connected to the recovery neutral wire to prevent the occurrence of overvoltage through the neutral wire recovery and the normal voltage Distribution board with a neutral wire recovery function comprising a neutral wire recovery device for maintaining.
The apparatus according to claim 1,
A current detector for detecting a current flowing in the neutral line;
A disconnection detector measuring the neutral voltage and the ground voltage and outputting a disconnection detection value to neutral disconnection when the neutral voltage and the ground voltage are detected;
A controller for generating control signals for image harmonic reduction and neutral line recovery according to the current detection value and the disconnection detection value output by the current detector and the disconnection detector;
Neutral recovery function is characterized in that it comprises an image harmonics reduction and neutral line recovery device to reduce the image harmonics flowing to the neutral line or to restore the neutral line in accordance with the control signal generated by the controller to maintain the equilibrium of the single-phase voltage Distribution overall.
3. The apparatus of claim 2,
Comparing the current value detected by the current detector with a reference set value, and when the detected current value exceeds the reference set value, it is determined that the image harmonic is increased and generates a control signal for reducing the image harmonic. Distribution board with neutral line recovery.
The method according to claim 2, wherein the image harmonic reduction and neutral recovery device,
A first switch operating according to a control signal for reducing image harmonics;
A zig-zag transformer that operates during the operation of the first switch to reduce an electric current flowing through a neutral line to remove image harmonics;
And a second switch for connecting each phase to the recovery neutral line (N) to maintain a single phase voltage balance.
In the method for reducing the image harmonics and recovering them in the case of neutral disconnection,
(a) detecting current flowing through the neutral line when power is supplied;
(b) comparing the detected current with a reference set value to determine whether image harmonics increase, and when the image harmonics increase, operating the zig-zag transformer to reduce image harmonics;
(c) determining whether an image harmonic is increased by detecting a current flowing in a neutral line after the jig-zag transformer operation, and operating the circuit breaker when the image harmonic is not reduced;
(d) detecting whether the neutral wire is disconnected by detecting the neutral wire and the ground voltage;
(e) if it is determined that the disconnection of the neutral wire is detected, operating a neutral wire restorer to recover the disconnected neutral wire;
(f) checking whether the neutral line is normally restored after the neutral line recovering operation, and operating a breaker when the neutral line is not normally restored;
(g) generating an alarm for neutral wire disconnection after the breaker operation or after the image harmonics are normally reduced or after the neutral wire is normally restored;
(h) if the alarm release request occurs after the alarm occurs, the distribution board control method with a neutral line recovery function comprising the step of releasing the generated alarm.

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