KR20200113749A - Direct current circuit breaker using power of direct current system - Google Patents

Abstract

According to an embodiment of the present invention, a DC circuit breaker using a power of a DC system includes: a detection unit for detecting each current in first and second lines of the DC system and a voltage therebetween; a determination unit for generating a control signal indicating whether to open or close each contact of the DC system according to the current and voltage detected by the detection unit; a power supply unit processing power and supplying the power to the detection unit and the determination unit; and a connection unit which connects between the first and second lines and the detection unit to detect the current and voltage, and connects between the first and second lines and the power supply unit to supply the power. The present invention provides the DC circuit breaker capable of reducing noise to signals of detected current and voltage.

Description

Direct current circuit breaker using power of direct current system

The present invention relates to a DC circuit breaker, and more particularly, to a DC circuit breaker that receives power from each line of a DC system and uses it to detect the current/voltage of the line and to control whether the line contact is cut off. .

In the transmission and distribution power system, overcurrent, short-circuit current, etc. may occur on the line, and a current circuit breaker is used to quickly cut off the current and protect power facilities. These current circuit breakers are largely classified into alternating current (AC) circuit breakers and direct current (DC) circuit breakers according to their type of power.

In the case of an AC circuit breaker, a gas circuit breaker (GCB) in which SF6 gas is applied as the main insulating medium is mainly applied inside a gas insulated switch (GIS) in an ultra-high pressure AC system of 154 kV or higher. In addition, a vacuum circuit breaker (VCB) is mainly applied in distribution AC systems below 22.9 kV class.

In the case of DC circuit breakers, air circuit breakers (ACB) are mainly applied in 1.5 kV class train DC systems, and in addition, miniature circuit breakers (MCB) and molding circuit breakers (MCCB) are applied in low voltage DC systems for indoor wiring. In recent years, various studies have been conducted on DC circuit breakers to be applied to high-voltage DC systems above distribution class.

On the other hand, in the AC system, the current zero point is naturally formed due to the alternating current/voltage characteristics, so when an accident occurs, the breaker is opened to endure the momentary arc and when the current zero point is formed, natural blocking through arc extinguishing is prevented. In progress. However, since a natural current zero point is not formed in the DC system, the current zero point must be artificially formed. As such, the application principles are different from each other, so the DC circuit breaker and the AC circuit breaker have to have different configurations.

1 schematically shows the configuration of a conventional AC circuit breaker.

Referring to FIG. 1, a conventional AC circuit breaker may include a detection unit 10, a determination unit 20, an opening/closing unit 30, and the like. At this time, the detection unit 10 detects the current and voltage of each line of the AC system using a current transformer (CT) and a voltage transformer (PT). The determination unit 20 determines the state of each line of the AC system using signals for the detected current and voltage, and when overcurrent, short circuit current, etc. are recognized as a result of the determination, a trip signal for blocking each contact ( trip signal). The opening/closing unit 30 is configured to drive on/off of the contact points C of each line of the AC system, and operates to cut off each contact point C according to a trip signal.

In particular, in order to supply power for its operation, the conventional AC circuit breaker used a power generated through the current transformer 21 of the detection unit 20 or an external power source (DC 24V or AC 110-220V) implemented separately.

However, in the case of the DC circuit breaker, since the current transformer 21 cannot be used to detect the current of each line of the DC system, there is a problem in that power supply through the current transformer 21 is impossible. In addition, when using an external power source to solve this problem, there is a problem in that the configuration becomes complicated.

In order to solve the problems of the prior art as described above, the present invention is a DC circuit breaker that receives power from each line of the DC system and uses it to detect the current/voltage of the line and to control whether the line contact is cut off. Its purpose is to provide.

In addition, another object of the present invention is to provide a DC circuit breaker capable of reducing noise for signals of detected currents and voltages.

In addition, the present invention has another object to provide a DC circuit breaker that is easy to maintain.

However, the problem to be solved by the present invention is not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

A DC circuit breaker according to an embodiment of the present invention for solving the above-described problems includes: (1) a detection unit for detecting currents for the first and second lines of the DC system and a voltage therebetween, (2) A determination unit that generates a control signal for opening/closing each contact of the DC system according to the current and voltage detected by the detection unit, (3) a power supply unit that processes power and supplies it to the detection unit and the determination unit, and (4) detection of current and voltage For example, the first and second lines and the detection unit are connected to each other, and a connection unit is connected between the first and second lines and the power supply unit to supply power.

The detection unit may detect the current from both ends of a shunt resistor connected to the first and second lines, respectively, and may detect the voltage from between one end of the first shunt resistor and the other end of the second shunt resistor. have.

The connection unit may be connected so that both ends of each shunt resistor are input to the detection unit, and a part of the first line located at one end of the first shunt resistor and a part of the second line located at the other end of the second shunt resistor are connected to the power supply unit. Can be connected to be input.

The detection unit may further include a converter for converting the detected analog signal of the current and voltage into a digital signal, and may transmit the converted digital signal to the determination unit.

The detection unit and the determination unit may be implemented on separate substrates, and the digital signal may be transmitted through a connection of a port provided thereto.

In the detection unit and the determination unit, a processing period of the digital signal may be longer than a processing period of the analog signal.

The converter may process analog signals for each of the current and voltage input from three input lines, and output the digital signal through one output line.

The DC circuit breaker according to an embodiment of the present invention may further include a separation operation unit configured to connect or separate at least one shunt resistor between both ends of the detection unit and the detection unit.

The separating operation unit may connect or separate them between one end of the first shunt resistor or the other end of the second shunt resistor and the power supply unit.

The DC circuit breaker according to the present invention configured as described above receives power from each line of the DC system and uses it to detect the current/voltage of the line and control whether the line contact is cut off. There is an advantage of solving the problem of the conventional DC circuit breaker, which cannot but be configured to supply external power as an alternative, because current detection and power supply using CT is impossible.

In addition, according to the present invention, since the detection unit converts into a DS that is resistant to noise for the AS and is capable of noise processing and transmits it to the determination unit, there is an advantage of reducing noise for signals of current and voltage detected by the detection unit.

In addition, the present invention provides a separation effect between a detection unit, which is a sensing circuit of current and voltage, and a determination unit, which is a main circuit that determines a sensing value and CS accordingly, an effect of separating the detection unit from a DC system line, and a detection unit and determination. It can satisfy the effect of cutting off the power supply to the wealth, and has the advantage of easier maintenance.

1 schematically shows the configuration of a conventional AC circuit breaker.
2 shows the appearance of a DC circuit breaker according to an embodiment of the present invention.
3 is a block diagram of a DC circuit breaker according to an embodiment of the present invention.
FIG. 4 is a block diagram illustrating FIG. 3 in more detail.
5 shows a state in which the separation operation part 600 is operated.

The above objects and means of the present invention, and effects thereof, will become more apparent through the following detailed description in connection with the accompanying drawings, and accordingly, a person having ordinary knowledge in the technical field to which the present invention belongs can facilitate the technical idea of the present invention. It will be possible to do it. In addition, in describing the present invention, when it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

The terms used in this specification are for describing exemplary embodiments, and are not intended to limit the present invention. In the present specification, the singular form also includes the plural form in some cases, unless specifically stated in the phrase. In the present specification, terms such as "include", "include", "provision" or "have" do not exclude the presence or addition of one or more other elements other than the mentioned elements.

In the present specification, terms such as “or” and “at least one” may represent one of words listed together, or a combination of two or more. For example, “or B” “at least one of “and B” may include only one of A or B, and may include both A and B.

In this specification, the description following “for example” may not exactly match the information presented, such as the recited characteristics, variables, or values, and tolerances, measurement errors, limitations of measurement accuracy, and other commonly known factors. It should not be limited to the embodiments of the invention according to the various embodiments of the present invention to effects such as modifications including.

In the present specification, when a component is described as being'connected' or'connected' to another component, it may be directly connected or connected to the other component, but other components exist in the middle. It should be understood that it may be possible. On the other hand, when a component is referred to as being'directly connected' or'directly connected' to another component, it should be understood that there is no other component in the middle.

In the present specification, when a component is described as being'on' or'adjacent' of another component, it may be directly in contact with or connected to another component, but another component exists in the middle. It should be understood that it is possible. On the other hand, when a component is described as being'directly above' or'directly' of another component, it may be understood that there is no other component in the middle. Other expressions describing the relationship between components, for example,'between' and'directly,' can be interpreted as well.

In this specification, terms such as'first' and'second' may be used to describe various elements, but the corresponding elements should not be limited by the above terms. In addition, the terms above should not be interpreted as limiting the order of each component, and may be used for the purpose of distinguishing one component from another component. For example, the'first element' may be named'second element', and similarly, the'second element' may also be named'first element'.

Unless otherwise defined, all terms used in the present specification may be used as meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

2 shows the appearance of a DC circuit breaker according to an embodiment of the present invention, and FIG. 3 shows a block diagram of a DC circuit breaker according to an embodiment of the present invention. In addition, FIG. 4 shows a block diagram illustrating FIG. 3 in more detail.

A DC circuit breaker according to an embodiment of the present invention, as shown in FIGS. 2 to 4, comprises a detection unit 100, a determination unit 200, an opening and closing unit 300, a power supply unit 400, and a connection unit 500. It includes, and may further include a separate operation unit 600 in addition. At this time, the detection unit 100 and the determination unit 200 or the determination unit 200 may be formed of an over current relay (OCR).

Hereinafter, for convenience of explanation, a high voltage is applied to the first line PL, but the current direction is in the lower direction in FIGS. 3 and 4, and a low voltage is applied to the second line NL, but the current direction is 3 and 4, it is assumed that it is in the upper direction, but the present invention is not limited thereto.

The detection unit 100 is configured to detect each current flowing in the first and second lines PL and NL of the DC system and the voltage between these lines PL and NL. Accordingly, the detection unit 100 may include a plurality of shunt resistors R ₁ and R ₂ , a first current detection unit 110, a second current detection unit 120, and a voltage detection unit 130.

The shunt resistors R ₁ and R ₂ are connected in series to each line PL and NL for current detection. At this time, the R ₁ one end (in Figure 4 the top of the R ₁₎ is the other end thereof is a high potential compared with the (FIG bottom of R ₁ in 4), (lower in Fig. 4, R ₂₎ of R ₂ other end is one end ( It is a high potential compared to the upper end of R ₂ in FIG. 4 ).

The first current detection unit 110 is connected to both ends of the first shunt resistor R ₁ and detects the first current I ₁ flowing through the first line PL. At this time, the first current detection unit 110 1 After detecting the voltage (V ₁ ) across the shunt resistor (R ₁ ) using a voltmeter, the first current (I ₁ ) is finalized by using Ohm's law (I ₁ =V ₁ /R ₁ ). Can be detected.

The second current detection unit 120 is connected to both ends of the second shunt resistor R ₂ and detects a second current flowing through the second line NL. At this time, the second current detection unit 120 detects the voltage (V ₂ ) applied to both ends of the second shunt resistor (R ₂ ) using a voltmeter, and then uses Ohm's law (I ₂ =V ₂ /R ₂ ). By using it, the second current I ₂ can be finally detected.

The voltage detector 130 detects a voltage V ₁₂ between the first line PL and the second line NL. That is, V ₁₂ is the voltage between the portions before the voltage drop occurs due to the shunt resistors R ₁ and R ₂ in each line PL and NL, that is, the voltage between _one end of R ₁ and the other end of R ₂ . At this time, the voltage detector 130 may detect the V _12, using the result detected in the detecting the V ₁₂ by using a voltmeter, or a separate, first and second current detection unit (110, 120).

The determination unit 200 determines the state of each line (or contact) of the DC system according to the current (I ₁ , I ₂ ) and voltage (V ₁₂ ) detected by the detection unit 100, and then, based on the determination result, each line This is a configuration that controls whether or not a trip signal is generated for off of the contact point. That is, the determination unit 200 generates a control signal CS for on/off of each contact according to the values of the current (I ₁ , I ₂ ) and voltage (V ₁₂ ) detected by the detection unit 100 You can control 300.

For example, when the detected current (I ₁ , I ₂ ) and voltage (V ₁₂ ) values exceed the reference value, the determination unit 200 may determine that an overcurrent or an accident current has occurred in a specific line. have. Accordingly, the determination unit 200 may generate a trip signal for blocking the contact point of a corresponding line as the control signal CS.

The opening/closing unit 300 drives on/off of a contact point of each line of the DC system according to the control signal CS of the determination unit 200. In particular, when the control signal CS of the trip signal is generated by the determination unit 200, the opening/closing unit 300 operates to cut off the corresponding contact.

For example, each contact point of the lines PL and NL may include a fixed contactor and a movable contactor, and the opening/closing unit 300 may operate the movable contactor according to the control signal CS. That is, the opening/closing part 300 may control the movable contactor to contact the fixed contactor to turn on the contact of the corresponding line. In addition, when a trip signal is generated, the opening/closing unit 300 may control the movable contact to be separated from the fixed contact, thereby blocking the contact of the corresponding line. In addition, the opening/closing unit 300 may include an extinguishing unit that extinguishes an arc that may occur due to contact and separation between the fixed contact and the movable contact.

The power supply unit 400 supplies power to the remaining configurations (in particular, the detection unit 100 and the determination unit 200) so that the remaining configurations such as the detection unit 100, the determination unit 200, and the opening/closing unit 300 can operate. Processed and supplied. In this case, the power supply unit 400 may receive power directly from each line (PL, NL) of the DC system and process it. For example, the power supply unit 400 may be formed of a switching mode power supply (SMPS).

The connection unit 500 connects between the first and second lines PL and NL and the detection unit 100 for detection of current and voltage, and the first and second lines PL and NL) and the power supply unit 400 are connected to each other. In this case, the connection part 500 includes a plurality of connection lines 510 that are passages for power supply, and a plurality of nodes 520 that are intersection points between the connection lines 510.

Specifically, the connection unit 500 is connected so that both ends of R ₁ are input to the first current detection unit 110 of the detection unit 100 so that the first current detection unit 110 can detect I ₁ , and R ₂ Both ends of are connected so that they are input to the second current detection unit 120 of the detection unit 100 so that the second current detection unit 120 can detect I ₂ . In addition, the connection unit 500 connects _one end of R ₁ and the other end of R ₂ to be input to the voltage detection unit 130, so that the voltage detection unit 130 can detect V ₁₂ . At the same time, the connection unit 500 is connected so that _one end of R ₁ and the other end of R ₂ are respectively input to the power supply unit 400, so that the power supply unit 400 can supply power in the remaining configuration.

That is, the DC circuit breaker according to an embodiment of the present invention has the connection part 500, so that the remaining components such as the detection unit 100, the determination unit 200, and the opening/closing unit 300 can operate. As the power supply unit 400 for supplying the power is connected to each line (PL, NL), it is possible to receive power for processing from them, and at the same time, the detection unit 100 is connected to each line (PL, NL). Current/voltage of the lines PL and NL can be detected. Accordingly, the present invention can solve the problem of the conventional DC circuit breaker that cannot but be configured to supply external power as an alternative to the current detection and power supply using the CT because the CT cannot be used.

On the other hand, in the case of the conventional AC circuit breaker, the detection value of the current/voltage of the AC system line was processed as an analog signal. In other words, since the current zero point can be formed naturally due to the alternating current/voltage characteristics in the AC system and only need to be filtered for a specific frequency band, the conventional AC circuit breaker transmits even if the current/voltage detection value is an analog signal. It was easy to process noise generated during the process.

However, in the case of a DC circuit breaker, since a natural current zero point is not formed, a current zero point must be artificially formed, and filtering processing for a specific frequency band is impossible due to the DC characteristic using the entire frequency band. Accordingly, in the DC circuit breaker, if the detection value for the current/voltage is an analog signal, it is virtually impossible to process noise generated during the transmission.

In order to solve this problem, the present invention can provide a means for reducing noise on a signal for a detected current and voltage. That is, the detection unit 100 further includes a converter 140 for converting the analog signal AS of the detected current and voltage into a digital signal DS, and converts the converted digital signal DS to the determination unit 200. send. For example, the converter 140 may be implemented using a micro controller unit (MCU) having an analog digital converter (ADC) function.

For example, the converter 140 processes AS for each of I ₁ , I ₂ , and V ₁₂ , which are outputs of the current detection units 110 and 120 and the voltage detection unit 130 input from three input lines, DS can be output through the output line. In this case, the DS output from one output line may include data for I ₁ , I ₂ , and V ₁₂ . Accordingly, the present invention has the advantage of simpler implementation of the configuration by reducing the output line of the converter 140.

In addition, according to the present invention, the detection unit 100 and the determination unit 200 may be implemented on separate substrates (eg, PCB, etc.) to have a structure in which they are connected. This structure may be a structure for easy maintenance of the DC circuit breaker. That is, since it is composed of substrates each having the detection unit 100 and the determination unit 200, when a specific part fails, only the substrate having the corresponding part can be replaced, thereby making it easier to maintain.

In this way, when the detection unit 100 and the determination unit 200 are implemented on separate substrates, the detection unit 100 and the determination unit 200 are connected to the detection unit 100 through the connection of the respective ports. DS can be transmitted with ). That is, the port 150 of the detection unit 100 may transmit the DS received from the converter 140 to a port (not shown) of the determination unit 200.

The ports of the detection unit 100 and the determination unit 200 may have a structure that can be directly connected to each other, or may have a structure connected between them by a connector. In this case, the DS may be transmitted between these ports through a serial communication method or a parallel communication method. For example, DS may be transmitted between these ports in an SPI method or a USART method.

Since the detection unit 100 converts the AS into a DS that is resistant to noise and capable of noise processing and transmits it to the determination unit 200, the present invention has an advantage of having a noise reduction effect. In particular, in the detection unit 100 and the determination unit 200, when the processing period of the DS is longer than the processing period of the AS, this noise reduction effect may be further enhanced.

In this case, the DS processing period is the length of the transmission line from the converter 140 to the port 150 of the detection unit 100, the length of the connection line between the ports of the detection unit 100 and the determination unit 200, and the determination unit 200 It may include a length of a transmission line from the port to the MCU of the determination unit 200 (DS is analyzed and determined to control CS generation). In addition, the AS processing section may include a length of a transmission line from the current detectors 110 and 120 or the voltage detector 130 to the converter 140.

5 shows a state in which the separation operation part 600 is operated.

In addition, the DC circuit breaker according to an embodiment of the present invention may further include a separation operation unit 600.

That is, the separation operation unit 600 is at both ends of at least one shunt resistor (R ₁ or R ₂ ) and any current detection unit 110 or 120 of the detection unit 100 (hereinafter referred to as “first separation targets” ) Can be connected between. In addition, the separation operation unit 600 is between both ends of at least one shunt resistor (R ₁ or R ₂ ) and the voltage detection unit 130 of the detection unit 100 (hereinafter, these are referred to as “second separation targets”). Can be connected. Further, the separated control panel 600 is the other end of one or R ₂ a R ₁ (in FIG. 4 as shown by the other end of R ₂₎ and the power supply unit 400 (hereinafter referred to as those "third separation target to") Can be connected between. Accordingly, the separation operation unit 600 may connect (on) or separate (off) the first to third separation objects to each other.

For example, referring to FIG. 4, the input terminal of the separation operation unit 600 may be connected to both ends of R ₂ , and the output terminal of the separation operation unit 600 may be connected to _two input terminals of the second current detection unit 120 , The output terminals of the separation operation unit 600 may be connected to two input terminals of the voltage detection unit 130. At the same time, the other end portion of R ₂ output from the output terminal of the separation operation unit 600 may be connected to the power supply unit 400.

When the separation operation unit 600 operates in separation, the connection line 510 with respect to the lines PL and NL connected to the detection unit 100 and the power supply unit 400 is cut off. Accordingly, since the detection unit 100 does not detect the current/voltage for the lines PL and NL, the detection value of the current/voltage is not provided to the determination unit 200, so that the first and second separation targets are separated. It can have an effect. At the same time, since the third separation targets are separated, the power supply unit 400 may stop supplying power to the remaining components.

In the case of performing maintenance, separation is required between the detection unit 100 operating as a sensing circuit for the lines PL and NL and the determination unit 200, which is the main circuit that determines the sensing value and CS accordingly. , The detection unit 100 must be insulated from the lines PL and NL, and the power supplied to the detection unit 100 and the determination unit 200 needs to be cut off. That is, when the separation operation is performed using the separation operation unit 600, the present invention provides a separation effect between the detection unit 100 and the determination unit 200 and insulation separation effect from the lines PL and NL of the detection unit 100 Wow, it is possible to satisfy the effect of cutting off the power supply to the detection unit 100 and the determination unit 200, and accordingly, maintenance may be further facilitated.

Referring to FIG. 5, the separation operation unit 600 displays a connection state or disconnection state of quarantine objects in operation of a manipulator 610 consisting of a groove, a projection, a button, etc. to enable a user's manipulation, and the manipulation of the manipulator 610 A display unit 620 may be included.

For example, as shown in FIG. 5(a), when the user moves the manipulator 610 in one direction, the objects to be isolated are separated, and the display unit 620 may display “ISOLATED”, which is a separate state. . In addition, as shown in FIG. 5B, when the user moves the manipulator 610 in another direction, the quarantine objects are connected, and the display unit 620 may display “CONNECTED”, which is a connection state according to the connection.

In the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention is not limited to the described embodiments, and should be defined by the claims to be described later and equivalents to the claims.

10, 100: detection unit 20, 200: determination unit
30, 300: opening and closing unit 110, 120: current detection unit
130: voltage detection unit 140: converter
150: port 400: power supply
500: connection part 510: connection line
520: bar 600: separate control unit
610: manipulator 620: display
AS: analog signal DS: digital signal
C: Contact I ₁ , I ₂ : Current
V ₁ , V ₂ , V ₁₂ : Voltage PL, NL: DC system line

Claims (8)

A detection unit for detecting currents for the first and second lines of the DC system and voltages therebetween;
A determination unit generating a control signal indicating whether to open or close each contact of the DC system according to the current and voltage detected by the detection unit;
A power supply unit processing power and supplying it to the detection unit and the determination unit; And
A connection part connecting between the first and second lines and the detection unit to detect current and voltage, and connecting between the first and second lines and the power supply unit to supply power;
DC circuit breaker using a power source of a DC system comprising a. The method of claim 1,
The detection unit detects the current from both ends of a shunt resistor connected to the first and second lines, respectively, and detects the voltage from between one end of the first shunt resistor and the other end of the second shunt resistor,
The connection part is connected so that both ends of each shunt resistor are input to the detection unit, and a part of the first line located at one end of the first shunt resistor and a part of the second line located at the other end of the second shunt resistor are input to the power supply unit. DC circuit breaker using the power of the DC system, characterized in that the connection is possible. The method of claim 1,
The detection unit further comprises a converter for converting the analog signal of the detected current and voltage into a digital signal, and transmits the converted digital signal to the determination unit DC circuit breaker using a power source of the DC system. The method of claim 3,
The detection unit and the determination unit are implemented on separate substrates, and the digital signal is transmitted through a connection of a port provided in each of the DC circuit breakers using a power source of a DC system. The method of claim 4,
In the detection unit and the determination unit,
The DC circuit breaker using the power of the DC system, characterized in that the processing period of the digital signal is longer than the processing period of the analog signal. The method of claim 4,
The converter is
A DC circuit breaker using a power supply of a DC system, characterized in that the analog signal for each of the current and the voltage input from three input lines is processed and the digital signal is output through one output line. The method of claim 1,
A DC circuit breaker using a power source of a DC system, further comprising a separation operation unit configured to connect or separate them between both ends of at least one shunt resistor and the detection unit. The method of claim 7,
The separation operation unit connects or separates one end of the first shunt resistor or the other end of the second shunt resistor and the power supply unit.

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