JP2011062067A - Dc power distribution system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dc power distribution system which can perform ac power linkage easily. <P>SOLUTION: The system includes: an ac feed line S; a dc power distribution line 8 connected to a dc power generating source for generating dc power; an accumulator bank 6 for storing and discharging dc power; and a direction control power conditioner 5 having power routes leading to three directions of the side of the ac feed line S, the side of the dc power distribution line 8, and the side of the accumulator bank 6 and capable of switching each power route. The three direction control power conditioner 5 includes: boosting units 31 to 33 for boosting power received from at least one of the power routes in three directions and sending to other power routes; measuring and monitoring units 22 to 24 for detecting the state of power of each power route; and switching units 28 to 30 for switching the power routes based on information detected by the measuring-monitoring units. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a DC power distribution system.

  In recent years, distributed power sources such as solar power generation and wind power generation have attracted attention. From the viewpoint of the environment, it is considered to be an urgent need to use the power generated from such a distributed power source in conjunction with an existing AC power system. Patent Document 1 below discloses a technique in which individual distributed power sources are AC-linked.

JP 2003-9425 A

  In the current AC power system, the frequency and phase are always synchronized from the host system to the end, and the relationship between the power generation and the load is always maintained at the same time and in the same amount. When the number of distributed power sources that should be AC-linked greatly increases, as a result, there are many undefined power sources other than those managed by the power company at any point in the system. In the case of AC interconnection, there is a problem that there is a concern that it may seriously affect the stable operation of the system.

  The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a DC power distribution system capable of easily performing AC interconnection.

  As means for achieving the above object, the invention of claim 1 includes an AC power supply path, a DC power supply path connected to a DC power source for generating DC power, a storage battery for storing and discharging DC power, A directional control power conditioner having at least three AC paths to the AC power supply path side, the DC power supply path side, and the storage battery side, and capable of switching each electric circuit; and the direction control power conditioner and the AC power supply path Power conversion means for interconverting direct current power and alternating current power interposed therebetween, wherein the direction control power conditioner boosts at least one received power of the at least three directions of electric circuit to another electric circuit Booster unit to be sent out, measurement / monitoring unit that detects the power status of each circuit, and circuit switching based on the detection information of this measurement / monitoring unit Characterized in place and a switching unit for performing.

  A second aspect of the invention is characterized in that, in the first aspect of the invention, the direct current generating power source constitutes a direct current distribution network together with a direct current load device and is connected to the direct current power supply path.

  According to a third aspect of the present invention, the AC feeding path is an AC bus in a distribution substation, and the direction control power conditioner and the storage battery are installed at or near the distribution substation. In addition, the DC feeding path is characterized in that it is a DC distribution line connected to the direction control power conditioner.

  According to a fourth aspect of the present invention, in the third aspect, the DC distribution line is configured by a plurality of sections each connected by a section switch, and the section switch controls the switching operation thereof. When the controller detects an abnormality in the power supply status in the corresponding section, the operation control is performed so that the section is disconnected from the DC distribution line.

  The invention according to claim 5 is the one according to any one of claims 1 to 4, further comprising a centralized monitoring device that detects the respective power statuses in the AC feeding path, the storage battery, and the DC feeding path, This centralized monitoring device is characterized in that it controls the switching of the electric circuit by outputting an operation command to the switching unit based on the detection result of the power status.

<Invention of Claim 1>
According to the first aspect of the present invention, the direction control power conditioner is provided at the connection point between the direct current side, the alternating current side, and the storage battery, and switching of the electric circuit is performed based on the power condition of the electric circuit from at least three directions leading to the power conditioner. As a result, AC / DC interconnection can be easily performed. Therefore, it is possible to open the door to active adoption in distributed power sources.

<Invention of Claim 2>
In the invention of claim 2, since the DC power generation network connected to the DC power supply path is constructed, simultaneous equality of generated power and load power such as AC interconnection, frequency synchronization, phase management, etc. The system stability can be improved because the frequency fluctuation due to fluctuations in supply and demand and failures does not occur.

<Invention of Claim 3>
If a DC power source is connected to an AC power distribution line, a power conditioner and a power storage device must be provided for each location where each power source is installed, which increases the installation cost and complicates the system configuration. In this regard, according to the third aspect of the present invention, the directional control power conditioner and the power storage device are collectively connected to or near the distribution substation by wiring the DC distribution line between the distribution substation and the DC power generation source. Therefore, the installation cost is low and the system configuration is simplified.

<Invention of Claim 4>
According to the invention of claim 4, when the controller of the section switch detects that a power abnormality has occurred in the section where the DC distribution line is laid, the section switch disconnects the section from the DC distribution line. Since the operation is controlled, it is possible to prevent the adverse effect of the abnormal section from extending to other sections.

<Invention of Claim 5>
According to invention of Claim 5, each power condition in an alternating current feeding path, a storage battery, and a direct current feeding path can be centrally managed by the centralized monitoring device. Moreover, if the centralized monitoring device performs power path switching control for the switching unit according to the power status, power switching control can also be unified.

1 is a block diagram illustrating a DC power distribution system according to a first embodiment. Block diagram showing direction control power conditioner Circuit diagram showing internal configuration of direction control power conditioner The block diagram which shows the principal part of the DC power distribution system which concerns on Embodiment 2. The block diagram which shows the principal part of the DC power distribution system which concerns on Embodiment 3. The block diagram which shows the principal part of the DC power distribution system which concerns on Embodiment 4.

<Embodiment 1>
In FIG. 1, reference numeral 1 denotes a distribution substation, and a high-voltage AC bus 2 is drawn from a 77 KV line through a circuit breaker or the like. A number of high-voltage AC distribution lines are branched from the high-voltage AC bus line 2. In FIG. 1, one specific high-voltage AC distribution line (AC feed line) connected to the high-voltage AC bus line 2 through a circuit breaker 3 An interconnected DC power distribution system is shown.

  A three-way control power conditioner 5 is connected to the circuit breaker 3 via a bidirectional AC / DC converter 4. Similarly, the three-way control power conditioner 5 is connected to a storage battery bank 6 installed in the distribution substation 1 via a circuit breaker 7. The above-described three-way control power conditioner 5 performs supply and demand management of power in the high-voltage DC distribution line 8 (DC power supply path) described below, and when there is surplus power on the high-voltage DC distribution line 8 side, the storage battery bank 6 Depending on the state of charging, the surplus is stored or is supplied (returned) to the high-voltage AC bus 2 side. Further, when there is a shortage of power on the high-voltage DC distribution line 8 side, the power is supplied from the high-voltage AC bus side or from the storage battery bank 6 side to the high-voltage DC distribution line 8 side according to the charging state of the storage battery bank 6. The feeding direction is switched so that the supply is performed. This will be described in detail later.

  Further, the above-described high-voltage DC distribution line 8 is branched into a plurality of lines and connected to a part of the three-way control power conditioner 5. Each distribution line 8 has a DC breaker 9 interposed therebetween. In this embodiment, the high-voltage DC distribution line 8 is installed using a distribution column owned by an electric power company or the like, and can be collocated with an existing AC distribution line.

  One of the high-voltage DC distribution lines 8 is connected to a low-voltage DC distribution network N via a high-voltage DC switch 10, a bidirectional DC / DC converter 11, and a bidirectional power conditioner 12.

  In addition, the bidirectional DC / DC converter 11 in this embodiment is reduced in size by performing a transformation with a high frequency as compared with a current pole transformer with a conventional commercial frequency.

  The bidirectional power conditioner 12 monitors the supply and demand situation of the power in the low-voltage DC distribution network N, and when there is a surplus in the power in the network N, the high-voltage DC distribution line 8 via the bidirectional DC / DC converter 11. When the surplus power is supplied to the side and the power in the network is insufficient, the feeding direction switching control is performed so that power is supplied from the high-voltage DC distribution line 8 side to the network N. Further, when the bidirectional power conditioner 12 detects a power abnormality (voltage abnormality) on the high-voltage DC distribution line 8 side or in the network N, the bidirectional power conditioner 12 determines that there is some abnormality on the distribution line 8 side or in the network N. A signal for opening the power supply path is transmitted to the high-voltage DC switch 10.

  The low-voltage DC distribution network N includes a plurality of (two in FIG. 1) solar power generators 14 connected via a power conditioner 13 that performs DC supply and demand control, and a low-voltage DC connected via a rectifier 15. The load device 16 is configured.

  The wiring network in the low-voltage DC distribution network N may be coordinated with the high-voltage DC distribution line 8 using an existing distribution column. In addition, the scale of the low-voltage DC distribution network N includes the total capacity of distributed power sources (for example, photovoltaic power generation devices) and the total capacity of low-voltage DC load devices, their local density, the total line length of the network, etc. Although it is limited by the installed capacity of the bidirectional DC / DC converter 11 used for the connection point with the power supply, the number of pole transformers in the current AC distribution is about several units based on the ratio of installed capacity to supply and demand area. It is desirable that the network has a capacity comparable to that of the equipment.

  In the example shown in FIG. 1, the case where the low-voltage DC distribution network N is directly connected as the distributed power source connected to the high-voltage DC distribution line 8 is also shown. For example, a distributed power source of a type such as a mega solar, a distributed power source 17 using biomass, or a wind farm 18 has a much larger power generation capacity and load capacity than the solar power generation device 14. For devices that exceed several hundred kilowatts, high-voltage direct current distribution via power conditioners 19 and 20, DC / DC converters 21 and 22, and high-voltage direct-current switches 23 and 24, respectively, without forming a low-voltage direct current distribution network N. What is necessary is just to connect to the electric wire 8.

  In addition, the bidirectional power conditioner 12 for the low-voltage DC distribution network system N and the power conditioners 19 and 20 for the other distributed power sources 17 and 18 are the power supply and demand status of the corresponding distributed power sources 17 and 18 and the low-voltage DC distribution network N. Is transmitted to the centralized monitoring device 21, whereby the power status in each of the distributed power sources 17, 18 or the network N is centrally monitored.

  The storage battery bank 6 installed in the distribution substation 1 is a large-sized secondary battery that can store and discharge DC power with DC power. For example, a sodium / sulfur battery or a redox flow battery can be used.

  Next, the three-way control power conditioner 5 will be described (see FIGS. 2 and 3). The three-way control power conditioner 5 is connected to electric paths R1 to R3 in three directions. That is, the electric circuit R1 leading to the AC bus 2, the electric circuit R2 leading to the high-voltage DC distribution line 8, and the electric circuit R3 leading to the storage battery bank 6. In the three-way control unit 5, there are measurement / monitoring units 22 to 24 for measuring the voltage / current (including the flow direction) and switching and controlling the flow direction of the power in each of the electric paths R 1 to R 3 leading to them. It is connected. Hereinafter, for convenience of explanation, the one corresponding to the high-voltage AC bus 2 side is referred to as the AC-side measurement / monitoring unit 22, and the one corresponding to the high-voltage DC distribution line 8 side is designated as the DC-side measurement / monitoring unit 23, the storage battery bank 6 side. The corresponding one is called a battery side measurement / monitoring unit 24.

  Each of the measurement / monitoring units 22 to 24 includes an instrument transformer and an instrument current transformer. In the case of the AC side measurement / monitoring unit 22, the bus side voltage VS and the received current IS (including the direction of the current) are detected, and the values are evaluated by the VI comparator 25. In the case of the DC side measurement / monitoring unit 23, the voltage VL and the current IL (including the direction) on the high voltage DC distribution line 8 side are detected and evaluated by the VI comparator 26. Further, in the case of the battery side measurement / monitoring unit 24, the storage battery side voltage VB and the current IB are detected, and the values are evaluated by the VI comparator 27.

  An AC side switching unit 28 is connected to the AC side measuring / monitoring unit 22. This AC-side switching unit 28 transmits the received power from the high-voltage AC bus 2 side to one of the electric circuits connected to the battery-side measurement / monitoring unit 24 and the DC-side measurement / monitoring unit 23 side, or conversely 6 or thyristors SCRs 11 and 12 for switching the feeding direction so that power from the high-voltage DC distribution line 8 side is sent back to the high-voltage AC bus 2 side via the AC-side measurement / monitoring unit 22 Yes.

  A DC side switching unit 29 is connected to the DC side measuring / monitoring unit 23. The DC side switching unit 29 is provided with thyristors SCRs 21 and 22, and connects the power (surplus power) from the high voltage DC distribution line 8 side to the AC side measuring / monitoring unit 22 and the battery side measuring / monitoring unit 24. The feeding direction can be switched so that power is supplied to the electric circuit, or conversely, the electric power received from these is distributed to the high-voltage DC distribution line 8 via the DC-side measurement / monitoring unit 23.

  A battery side switching unit 30 is connected to the battery side measurement / monitoring unit 24. The battery side switching unit 30 is also connected to the thyristors SCRs 31 and 32 in the same manner as the other switching units 28 and 29, and the stored electric power is stored on the AC side measurement / monitoring unit 22 side or the DC side measurement / monitoring unit 23. The feeding direction can be switched so that power is transmitted to the power supply side, or power (surplus power) from the high-voltage AC bus 2 side or the high-voltage DC distribution line 8 side is received.

  Further, boost units 31 to 33 are connected to the switching units 28 to 30, respectively. The boosting units 31 to 33 are for boosting the received voltage received by the three-way control unit 5 and sending it to the power supply systems on the bus 2 side, the storage battery bank 6 side, and the distribution line 8 side. Since the received voltage has the property of fluctuating depending on the load power and the voltage drop rate of the system, the setting of the supply voltage to each power supply system (the set voltage set for each booster unit 31 to 33) takes into account the daily time fluctuation rate To be determined. This setting command may be based on, for example, a command from the centralized monitoring device 21 or may be set autonomously by each of the boosting units 31 to 33 itself.

  The boosting unit 31 connected to the AC side switching unit 28 is configured such that the set voltage Vsd is input as the reference voltage of the VI comparator 25 of the AC side measuring / monitoring unit 22. The VI comparator 25 compensates by monitoring voltage / current whether or not the boosting state by the corresponding boosting unit 31 is functioning reliably. This is a set voltage VLP of the booster unit 32 connected to the DC side switching unit 29, and this voltage is inputted as a reference voltage of the VI comparator 26 in the DC side measuring / monitoring unit 23. This voltage is the storage battery. This is the delivery voltage for the bank 6 or bus 2 side. Similarly, the set voltage of the boosting unit 33 connected to the battery side switching unit 30 is VBP, which is the reference voltage of the corresponding VI comparator 27, and this voltage is the supply voltage for the distribution line side or bus side. .

Subsequently, the operation of the three-way control power conditioner 5 will be described.
(1) Normal power transmission (power transmission from the bus side to the distribution line side)
When the centralized monitoring device 21 determines that the current status is a status to be normally transmitted based on information on the voltage / current (including the flow direction) detected by each of the measurement / monitoring units 22 to 24, only the thyristor SCR21 is used. A gate current is supplied to turn on and other thyristors are turned off. Thus, power from the bus 2 side is transmitted to each distribution line 8 through the thyristor SCR 21 and consumed by the low-voltage DC distribution network N or the like. At this time, the supply voltage from the bus side is the set voltage VSD of the boosting unit 31.

  During normal power transmission, when the central monitoring device 21 detects that the current on the distribution line 8 side becomes IL <0, that is, when it is detected that a surplus of power is generated on the distribution line 8 side. The centralized monitoring device 21 outputs a command signal to turn on the thyristor SCR12 at the same time as turning off the thyristor SCR21.

If there is no surplus power on the distribution line 8 side, that is, if the DC side measurement / monitoring unit 23 detects that IL = 0 and VL is lower than the specified value, the above-described busbar is again detected by the centralized monitoring device 21. The mode returns to the normal power transmission mode from the second side.
(2) When power is supplied from the storage battery bank 6 to the distribution line and when charging is performed with electric power from the distribution line side
When the central monitoring device 21 determines that the storage battery bank 6 is almost fully charged and the power on the distribution line 8 side is insufficient, the central monitoring device 21 turns on only the thyristor SCR 22. At this time, since VBP> VL, the charging power of the storage battery bank 6 is transmitted to the distribution line 8 side. As a result, it is detected that surplus power is generated on the distribution line 8 side (IL <0), and when the centralized monitoring device 21 determines that the storage battery side should be charged, the centralized monitoring device 21 determines that the thyristor 21 The thyristor SCR32 is turned on simultaneously with turning off the SCR22. At this time, since the relationship of VB <VL is established, the storage battery bank 6 is charged with surplus power on the power distribution side.

When the DC side measurement / monitoring unit 23 detects that IL = 0 and VL has fallen below the specified value, the power transmission mode from the storage battery bank 6 to the distribution line 8 is restored.
(3) When power is transmitted from both the bus 2 side and the storage battery bank 6 side to the distribution line 8 side, and when the surplus on the distribution line 8 side is stored. The distribution line 8 side is short of power, and the storage battery bank 6 and When the centralized monitoring device 21 determines that power should be supplied from both sides of the bus 2, both the thyristors SCRs 21 and 22 are turned on. At this time, electric power from the bus 2 side and the storage battery bank 6 side is supplied to the distribution line side by a distribution ratio based on the set voltage of the boosting units 31 and 33.

When it is detected that IL <0, both the thyristors SCRs 21 and 22 are turned off, and at the same time, the thyristor SCR 32 is turned on to supply charging power to the storage battery bank 6. When IL = 0 and VL falls below the specified value, the mode again returns to the power transmission mode from the bus 2 side and the storage battery bank 6 side to the distribution line 8 side.
(4) When power is transmitted from both the bus 2 side and the storage battery bank 6 side to the distribution line 8 side, and when the surplus on the distribution line 8 side is sent back to the bus line side From the bus 2 side / storage battery bank 6 side However, if the centralized monitoring device 21 determines that the surplus power on the distribution line 8 side should be sent back to the bus 2 side instead of the storage battery bank 6 side, the thyristor SCR 21 , 22 are turned off and the thyristor SCR 12 is turned on at the same time. In this case, VS <VLP.
(5) When charging the storage battery bank 6 using midnight power The centralized monitoring device 21 is switched to a control mode in which charging of the storage battery bank 6 is prioritized at a fixed time zone of midnight. In this case, the thyristor SCR 32 is turned on, and the storage battery bank 6 is charged with power from the distribution line 8 side.

  In addition, it may be made to store using late-night electric power from the bus-bar side, and may be used together.

  By the way, in Embodiment 1, the division | segmentation switch 35 in which opening / closing control is made by the division | segmentation controller 34 is provided in the several places of each high voltage DC distribution line 8. FIG. Further, a loop point switch 36 for connecting to another high voltage DC distribution line 8 is provided at the end of the high voltage DC distribution line 8 so that the switching operation is controlled by the loop point controller 37. It has become. The segment controller 34 and the loop point controller 37 detect the voltage / current (including the flow direction) of the section of the high-voltage DC distribution line 8 to which the segment controller 34 and loop point controller 37 belong, and based on the detected value, the segment controller 34 or the loop point controller The operation of the device 36 is controlled. That is, when it is detected that some kind of power abnormality has occurred in the corresponding section, only the corresponding section is separated from the others, and power transmission to the same section is stopped. By doing so, power transmission to other healthy sections is ensured.

  As described above, according to the first embodiment, the three-way control power conditioner is interposed at the three interconnection points of the AC feeding path, the high-voltage DC distribution line, and the storage battery bank, and the feeding direction is switched according to the power balance. Therefore, it is possible to smoothly connect AC and DC. In addition, the constructed DC distribution network does not require complicated controls such as frequency control, phase synchronization control, and power factor control that are required during AC interconnection. In addition, if a DC distribution line is laid using an existing distribution column, the existing facility can be economically switched to a DC distribution network. For this reason, it is possible to open the door to active adoption of distributed power sources.

<Embodiment 2>
FIG. 4 shows Embodiment 2 of the present invention. The first embodiment shows an example in which the low-voltage DC distribution network N is connected to the high-voltage DC distribution line. In the second embodiment, the low-voltage DC distribution network N is connected to the high-voltage AC distribution line 50.

  Specifically, a three-way control power conditioner 53 is connected to the high-voltage AC distribution line 50 via a switch 51 and an AC / DC converter 52. Since the three-way control power conditioner 53 is substantially the same as the structure described in the first embodiment, it will not be described again here. As in the first embodiment, a storage battery bank 54 is connected to the three-way control power conditioner 53, and a low-voltage DC distribution network N is connected to the other DC power supply paths.

  In the low-voltage DC distribution network N according to the second embodiment, in addition to the solar power generation device 56 connected via the power conditioner 55, the small-scale server center 58 that is DC-fed via the rectifier element 57 (to prevent instantaneous power failure) Or a charger 60 for an electric vehicle equipped with a battery 61 that is also DC-fed via the rectifying element 62.

  Other configurations are the same as those of the first embodiment.

  In this way, even when the high-voltage distribution network is not converted to direct current, only the low-voltage side can be converted to direct-current by performing AC interconnection via the three-way control power conditioner and the AC / DC converter having a boost function. .

<Embodiment 3>
The third embodiment is also an example in which a plurality of distributed power sources are connected to the high-voltage AC distribution line 50. The mega solar, the biomass power generation apparatus 70, and the wind farm 73 shown here are all distributed power sources with a large capacity of several hundred KW to 1,000 KW. As in the other embodiments, the storage battery banks 74 and 75 are connected via the three-way control power conditioners 71 and 72.
Other configurations are the same as those of the second embodiment.

<Embodiment 4>
The fourth embodiment shown in FIG. 6 additionally shows a case where an AC-compatible device 76 existing in each consumer is connected to the power distribution system of the second embodiment (see FIG. 4). Components similar to those in the second embodiment are denoted by the same reference numerals and description thereof is omitted.
Each AC compatible device 76 is connected to the low voltage DC network N via a DC / AC converter 77 corresponding to each device capacity. In this case, each AC compatible device 77 does not need to be synchronized with the AC component on the system side.
In the present embodiment, at the stage where the storage battery bank 54, the three-way control power conditioner 53, etc. are not sufficiently prepared, it is important to enable connection with AC compatible devices in the consumer. Can respond to requests reliably. Further, in the transitional period as described above, facilities such as the storage battery bank 54 and the three-way control power conditioner 53 may be installed using, for example, a utility pole.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, the operation of the three-way control power conditioner is controlled based on a command from the centralized monitoring device. However, until the monitoring system is constructed, the centralized monitoring device Instead, it may be in the form of autonomous control of the three-way control power conditioner itself. It can also be used in combination with a centralized monitoring device. In that case, it also serves as compensation when an abnormality occurs in the monitoring system.
(2) In the above embodiment, the thyristor is provided for switching the electric circuit in the three-way control power conditioner. However, it may be replaced with another element having the same function or a circuit configuration having the same function.
(3) Although the number of switchable electric circuits in the three-way control power conditioner is three in the above embodiment, the number of electric circuits is at least as long as it includes at least three of the AC power supply path, the DC power supply path, and the storage battery side. Should not be limited.

DESCRIPTION OF SYMBOLS 1 ... Distribution substation 2 ... AC bus 5, 53, 71, 72 ... Three-way control power conditioner 6, 54, 74, 75 ... Storage battery bank 8 ... High voltage DC distribution line (DC feeding path)
DESCRIPTION OF SYMBOLS 21 ... Centralized monitoring apparatus 22-24 ... Measurement / monitoring unit 25-27 ... VI comparator 28-30 ... Switching unit 31-33 ... Boosting unit 34 ... Division controller 35 ... Division switch N ... Low voltage DC distribution network S ... AC Feeding path

Claims (5)

AC feeding path,
A DC power supply path connected to a DC power source that generates DC power;
A storage battery for storing and discharging DC power; and
A directional control power conditioner having at least three AC paths to the AC power supply path side, the DC power supply path side, and the storage battery side, and capable of switching each electric circuit;
Power conversion means interposed between the directional control power conditioner and the AC power supply path to mutually convert DC power and AC power,
The direction control power conditioner is a step-up unit that boosts at least one received power of the electric circuit in at least three directions and sends it to another electric circuit;
A measurement / monitoring unit that detects the power status of each circuit;
A DC power distribution system comprising: a switching unit that switches an electric circuit based on detection information of the measurement / monitoring unit. The DC power distribution system according to claim 1, wherein the DC power generation power source forms a DC distribution network together with a DC load device and is connected to the DC power supply path. The AC power supply path is an AC bus in a distribution substation, the direction control power conditioner and the storage battery are installed at or near the distribution substation, and the DC power supply path is connected to the direction control power conditioner. The direct current distribution system according to claim 2, wherein the direct current distribution line is a direct current distribution line. Each of the DC distribution lines is configured by a plurality of sections connected by a section switch, and the section switch includes a controller that controls the switching operation of the section switch. 4. The DC power distribution system according to claim 3, wherein when an abnormality is detected, operation control is performed so as to disconnect the section from the DC distribution line. A centralized monitoring device is provided for detecting respective power statuses in the AC power supply path, the storage battery, and the DC power supply path, and the centralized monitoring device outputs an operation command to the switching unit based on the detection result of the power status. The DC power distribution system according to any one of claims 1 to 4, wherein switching control of the electric circuit is performed.

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