JP2018064346A - Power system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a current exceeding overcurrent capability from flowing to an existing premise wiring.SOLUTION: A power system 100 for supplying power of a power system 14 to a load facility 16 through premise wiring 116 includes a power supply facility 120 connected with the premise wiring, and a circuit breaker 114c connected with the premise wiring, and having a breaking capacity obtained by reducing the maximum capacity of the power supply facility from the breaking capacity of the circuit breaker 114c that had been connected with the premise wiring before power supply facility is connected. With such an arrangement, a current exceeding the overcurrent capability can be prevented from flowing to the premise wiring.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power system capable of connecting a power supply facility to a customer premises.

  A consumer receives electricity (commercial power) supplied from an electric power company and uses electricity in a load facility (general-purpose electric work) on the premises. It is also possible to provide power generation facilities such as solar power generation facilities on the premises, operate load facilities (for example, Patent Document 1), and sell surplus power to the power company.

JP 2013-247737 A

  Currently, single-phase, three-wire type power generation facilities such as solar power generation facilities and power supply facilities such as batteries are used. However, when energy-saving equipment becomes more widespread in the future and the power demand on the premises decreases, it does not necessarily need to be a single-phase three-wire system, for example, it is connected only to a single-phase two-wire equivalent to one of the single-phase three-wire It is conceivable to install a small power supply facility.

  Then, it is possible not only to connect the power supply facility to the secondary side of the service breaker of the distribution board, but also to directly connect to the secondary side of the single-phase two-wire circuit breaker. In this case, the construction cost can also be reduced by connecting the power supply equipment to an existing outdoor outlet and utilizing the existing premises wiring as it is.

  However, the overcurrent withstand capability is predetermined for the premises wiring connected to each circuit breaker in the distribution board, and simply connecting the power supply equipment to the secondary side of such a circuit breaker The following problems can occur. That is, the overcurrent withstand capability of the local wiring located on the secondary side of the wiring breaker is determined based on the breaking capacity of the wiring breaker. Therefore, when power is directly supplied from the power supply facility to the load facility without going through the wiring circuit breaker, a current exceeding the overcurrent withstand capability may flow through the premises wiring.

  In view of such a problem, an object of the present invention is to provide an electric power system capable of preventing a current exceeding an overcurrent withstand capability from flowing through an existing premises wiring.

  In order to solve the above-mentioned problems, the power system of the present invention for supplying the power of the power system to the load equipment through the on-site wiring, the power supply equipment connected to the on-site wiring, and the power supply equipment connected to the on-site wiring. And a breaker having a breaking capacity obtained by subtracting the maximum capacity of the power supply facility from the breaking capacity of the breaker connected to the premises wiring before being connected.

  Another power system of the present invention for supplying power from a power system to a load facility through a premises wiring is a power supply facility connected to the premises wiring and a power supply facility connected to the premises wiring from the overcurrent withstand capability of the premises wiring. And a circuit breaker having a breaking capacity obtained by reducing the maximum capacity.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to prevent the electric current exceeding an overcurrent tolerance from flowing into the existing premise wiring.

It is explanatory drawing which showed the basic connection aspect of the electric power system. It is explanatory drawing for demonstrating the connection aspect of electric power supply equipment. It is explanatory drawing which showed the connection aspect of the electric power system in 1st Embodiment. It is explanatory drawing which showed the connection aspect of the electric power system in 2nd Embodiment. It is explanatory drawing which showed the connection aspect of the other electric power system in 2nd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is an explanatory diagram showing a basic connection mode of the power system 100. The power system 100 is supplied with electricity (commercial power) from the power system 14 through the lead-in line 12. Such a power system 100 is configured in units of low-voltage power receiving consumers, and the scope thereof is not limited to houses and the like as long as it is a general electric work, such as a hospital, factory, hotel, leisure facility, commercial facility, condominium, etc. It may be a building unit or a part of a building.

  The power system 100 includes a power meter 112, a distribution board 114, local wiring 116, and an outlet 118.

  The power meter (watt-hour meter) 112 is connected to the power system 14 via the lead-in line 12 and measures a current value (consumption and power sale) flowing between the lead-in line 12 and the power system 100.

  The distribution board 114 is connected to the power meter 112 and is connected to a service circuit breaker (service breaker) 114a indicating a contracted capacity, a leakage breaker (leakage breaker) 114b that cuts off the supply of electricity in response to detection of a leakage, and a premises A wiring breaker (safety breaker) 114c is connected to the wiring 116 and cuts off the supply of electricity when the current flowing through the local wiring 116 exceeds the breaking capacity (for example, 20A).

  Here, the consumer connects the load facility 16 to an outlet 118 serving as an end of the premises wiring 116, and is supplied with electric power through the circuit breaker 114c. The load facility 16 can be connected to an indoor outlet 118a as shown by a solid line, or can be connected to an outdoor outlet 118b as shown by a broken line. In such a configuration, since all the electric power supplied to the load facility 16 is routed through the wiring breaker 114c, the breaking capacity of the wiring breaker 114c is designed to be equal to or less than the overcurrent withstand capability of the local wiring 116. Will be.

  Consider connecting the power supply facility 120 to the power system 100 described above. Therefore, the power system 100 includes a power supply facility 120 in addition to the power meter 112, the distribution board 114, the local wiring 116, and the outlet 118. Here, the power supply facility 120 supplies power to the load facility 16 that consumes electrical energy in preference to the power system 14. Examples of such power supply facilities 120 include renewable energy power generation facilities such as solar power generators, wind power generators, hydroelectric power generators, geothermal power generators, solar thermal power generators, atmospheric heat power generators, fuel cells, and internal combustion power generation. A storage battery or the like can be used.

  Such power supply equipment 120 is generally used connected to a single-phase three-wire (200 V). In this case, an interconnection breaker (200V) is provided in place of the circuit breaker 114c, and the power supply facility 120 is connected to the interconnection breaker, or a separate individual is provided from the primary side of the earth leakage breaker 114b. The power supply facility 120 must be connected via a circuit breaker (200V).

  However, in the future, when energy-saving devices become widespread and the power demand of the power system 100 decreases, a single-phase three-wire N-phase like this embodiment does not necessarily require a single-phase three-wire power supply facility. Only one of the R phase (voltage line) and T phase (voltage line) for the (neutral wire) is connected to one of the single phase two wires (R phase and N phase, or T phase and N phase). A small output power supply facility 120 will be installed.

  FIG. 2 is an explanatory diagram for explaining a connection mode of the power supply facility 120. If it can be operated with single-phase two-wires as described above, it prevents overcurrent and leakage to the outdoor outlet 118b that branches off from the existing on-site wiring 116 as shown in FIG. Thus, the power supply facility 120 can be connected through the individual circuit breaker 122, and the wiring in the power system 100 can be simplified.

  However, as described above, the breaking capacity of each wiring breaker 114c in the distribution board 114 and the overcurrent withstand capability of the local wiring 116 are determined at the time of installation (for example, both are 20A). If the power supply facility 120 is simply connected to the secondary side of the circuit breaker 114c as described above, the following problem may occur. In other words, the wiring breaker 114c can supply current up to 20A, which is the breaking capacity. On the other hand, the power supply facility 120 can also supply a current of 5 A in parallel with the power from the circuit breaker 114c. In this case, the load facility 16 can be supplied with a total current of 25 A. If it does so, the electric current exceeding 20A may flow into the premise wiring 116 arrange | positioned so that overcurrent tolerance may be 20A, and there exists a possibility of causing a heat_generation | fever and durability deterioration.

(First embodiment)
FIG. 3 is an explanatory diagram showing a connection mode of the power system 100 according to the first embodiment. The on-site wiring 116 is usually installed together with the customer facility. Therefore, it is inefficient to change the premises wiring 116 each time according to the installation, addition, and change of the power supply facility 120. Therefore, in the first embodiment, the circuit breaker 114c is changed (replaced) based on the overcurrent capability of the local line 116 without changing the local line 116.

  Specifically, first, an appropriate breaking capacity of the wiring breaker 114c is derived. Such an appropriate breaking capacity is obtained, for example, by subtracting the maximum capacity (for example, 5A) of the power supply facility 120 from the overcurrent withstand capability (for example, 20A) of the premises wiring. Here, an appropriate breaking capacity is 20A-5A = 15A. Therefore, as shown in FIG. 3, the existing circuit breaker 114c is replaced with a circuit breaker 114c having a breaking capacity of 15A.

  Then, as shown in FIG. 3, the exchanged circuit breaker 114c can supply current only up to 15A which is the breaking capacity. The power supply facility 120 can also supply a current of 5 A in parallel with the power from the wiring breaker 114c. In this case, the load facility 16 is supplied with a current up to 20 A, which is the total, but since 20 A is equal to the overcurrent withstand capability of the premises wiring 116, no problem occurs.

  In this way, by exchanging the circuit breaker 114c with a breaking capacity obtained by subtracting the maximum capacity of the power supply facility 120 from the overcurrent withstand capability of the local wiring 116, a current exceeding the overcurrent withstand capability flows through the local wiring 116. It becomes possible to prevent.

  Further, an appropriate breaking capacity of the wiring breaker 114c can be derived by the following procedure. That is, in order to avoid useless excessive design, as described above, the breaking capacity of the circuit breaker 114c and the overcurrent withstand capability of the local wiring 116 are designed to be approximately equal (however, the breaking capacity ≦ Overcurrent capability).

  Therefore, the breaking capacity of the easily accessible circuit breaker 114c can be used instead of the overcurrent withstand capability of the local wiring 116. For example, the maximum capacity (for example, 5A) of the power supply facility 120 is appropriately reduced by subtracting the maximum capacity (for example, 5A) of the power supply facility 120 from the interrupting capacity (for example, 20A) of the circuit breaker 114c connected to the premises wiring 116 before the power supply facility 120 is connected. The breaking capacity 15A is obtained. Thus, the existing wiring breaker 114c can be replaced with a wiring breaker 114c having a breaking capacity of 15A in the same manner as described above.

  As described above, the circuit breaker 114c having the breaking capacity obtained by subtracting the maximum capacity of the power supply facility 120 from the breaking capacity of the circuit breaker 114c connected to the premises wiring 116 before the power supply facility 120 is connected. By exchanging, it is possible to prevent the current exceeding the overcurrent capability from flowing through the local wiring 116.

(Second Embodiment)
In the first embodiment described above, an example in which the circuit breaker 114c is changed (replaced) based on the overcurrent capability of the local wiring 116 has been described. In the second embodiment, the on-site wiring 116 is protected by devising the processing in the power supply facility 120 without changing the wiring circuit breaker 114c.

  FIG. 4 is an explanatory diagram showing a connection mode of the power system 200 in the second embodiment. In FIG. 4, the movement of power is indicated by a solid line, and the flow of a signal including information is indicated by a dashed arrow. The power system 200 includes a power meter 112, a distribution board 114, local wiring 116, an outlet 118, a power supply facility 220, and an ammeter 224. However, since the power meter 112, the distribution board 114, the local wiring 116, and the outlet 118, which have already been described as the constituent elements in the first embodiment, have substantially the same functions, redundant description is omitted here. Now, the power supply equipment 220 and the ammeter 224 having different configurations will be mainly described.

  The ammeter 224 is installed between the connection point P between the local wiring 116 and the power supply facility 220 and the load facility 16, and measures the current flowing from the connection point P to the load facility 16.

  The power supply facility 220 includes at least a power generation unit 120a and a control unit 120b. The power generation unit 120a is composed of, for example, a fuel cell, and generates electricity by converting other energy into electric energy. The control unit 120b is composed of a semiconductor integrated circuit including a central processing unit (CPU), a ROM storing programs, a RAM as a work area, and the like, and controls the output of the power generation unit 120a.

  In particular, in the present embodiment, the control unit 120b limits the output of the power generation unit 120a in the power supply facility 220 so that the current measured by the ammeter 224 is equal to or less than the overcurrent capability (eg, 20 A) of the premises wiring 116. .

  For example, if the current consumed by the load facility 16, that is, the current (a) flowing from the connection point P to the load facility 16 is less than 5 A, the power supply facility 220 provides all the power. Therefore, the current (b) flowing from the power supply facility 220 to the connection point P is equal to the current (a), and the current (c) flowing from the wiring breaker 114c to the connection point P is 0A.

  Further, when the current (a) is 5A or more, the current (b) flowing from the power supply facility 220 to the connection point P becomes the maximum value 5A, and the current (c) flowing from the wiring breaker 114c to the connection point P is The difference between the current (a) and the current (b) (current (a) −current (b)) is covered.

  Then, when it is measured through the ammeter 224 that the current (a) exceeds 20A, that is, when the current (c) flowing from the circuit breaker 114c to the connection point P exceeds 15A, the control unit 120b The output of the power generation unit 120a in the power supply facility 220 is limited so that the current (a) is 20 A or less, which is the overcurrent withstand capacity of the premises wiring 116, and finally the output is set to zero. Thus, the current (c) flowing from the circuit breaker 114c to the connection point P is equal to the current (a). At this time, if a current exceeding 20 A continues to flow to the load facility 16, the supply of power from the circuit breaker 114 c is interrupted, and the local wiring 116 is protected.

  The output limitation of the power generation unit 120a is executed by disconnecting the output of the power generation unit 120a. In the circuit breaker 114c, for example, the operation time limit is determined in a stepwise manner for each excess current, such as 20 minutes if it is 22A or less and 10 minutes if it is 24A or less, and a short overcurrent is allowed. Therefore, it can also be realized by gradually reducing the output of the power generation unit 120a within the permissible range to finally zero.

  When the current (a) becomes 20 A or less through the ammeter 224, the control unit 120b gradually increases the output of the power generation unit 120a in the power supply facility 220 under the condition that the current (a) becomes 20 A or less.

  Thus, in the power supply facility 220, the on-site wiring 116 is configured to limit the output of the power generation unit 120 a in the power supply facility 220 so that the current measured by the ammeter 224 is equal to or less than the overcurrent tolerance of the on-premises wiring 116. Therefore, it is possible to prevent a current exceeding the overcurrent tolerance from flowing.

  Here, the example in which the ammeter 224 is installed between the connection point P between the local wiring 116 and the power supply facility 220 and the load facility 16 has been described. However, the wiring breaker 114c and the local wiring 116 are provided. When it is easier to install the ammeter 224 between the power supply facility 220 and the connection point P, the ammeter 224 may be disposed at this position.

  FIG. 5 is an explanatory diagram showing a connection mode of another power system 300 in the second embodiment. Again, the movement of power is indicated by a solid line, and the flow of a signal including information is indicated by a dashed arrow. The power system 300 includes a power meter 112, a distribution board 114, local wiring 116, an outlet 118, a power supply facility 220, and an ammeter 224. The power system 300 is different in arrangement only from the power system 200 and has substantially the same function, and therefore a duplicate description is omitted.

  In the power system 300, the ammeter 224 is installed between the wiring breaker 114 c and the connection point P between the local wiring 116 and the power supply facility 220, and the current flowing from the wiring breaker 114 c to the connection point P. Measure. The control unit 120b can detect the current output from the power supply facility 220. The control unit 120b then supplies the power supply facility 220 so that the sum of the current measured by the ammeter 224 and the current output from the power supply facility 220 is equal to or less than the overcurrent withstand capacity (for example, 20A) of the premises wiring 116. Limit the output of.

  For example, if the current consumed by the load facility 16, that is, the current (a) flowing from the connection point P to the load facility 16 is less than 5 A, the power supply facility 220 provides all the power. Therefore, the current (b) flowing from the power supply facility 220 to the connection point P is equal to the current (a), and the current (c) flowing from the wiring breaker 114c to the connection point P is 0A.

  Further, when the current (a) is 5A or more, the current (b) flowing from the power supply facility 220 to the connection point P becomes the maximum value 5A, and the current (c) flowing from the wiring breaker 114c to the connection point P is The difference between the current (a) and the current (b) is covered.

  When the current output from the power supply facility 220 reaches 5 A and the current (c) measured through the ammeter 224 exceeds 15 A, that is, the current (a) flowing from the connection point P to the load facility 16. When the current exceeds 20A, the control unit 120b makes the sum of the current (b) and the current (c) equal to or less than 20A, which is the overcurrent withstand capability of the local wiring 116, that is, the current (c) becomes 15A or less. Thus, the output of the power generation unit 120a in the power supply facility 220 is limited, and finally the output is set to zero. Thus, the current (c) flowing from the circuit breaker 114c to the connection point P is equal to the current (a). At this time, if a current exceeding 20 A continues to flow to the load facility 16, the supply of power from the circuit breaker 114 c is interrupted, and the local wiring 116 is protected.

  Then, when the sum of the current (b) and the current (c) is 20 A or less, the control unit 120 b uses the power supply facility 220 under the condition that the sum of the current (b) and the current (c) is 20 A or less. The output of the power generation unit 120a is gradually increased.

  As described above, in the power supply facility 220, the sum of the current measured by the ammeter 224 and the current output from the power supply facility 220 is equal to or less than the overcurrent withstand capacity of the local wiring 116. With the configuration that limits the output of the power generation unit 120a, it is possible to prevent the current exceeding the overcurrent capability from flowing through the local wiring 116.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above-described embodiment, an example in which the power supply facility 120 is connected to the outdoor outlet 118b through the individual circuit breaker 122 has been described. However, for the outlet 118 including the outdoor outlet 118b, a normal electric device is used. The present invention can be applied not only to a possible 100V but also to a 200V capable of using an air conditioner.

  INDUSTRIAL APPLICABILITY The present invention can be used for a power system that can connect a power supply facility to a customer premises.

14 Power system 16 Load facility 100, 200, 300 Power system 112 Power meter 114 Distribution board 114c Circuit breaker 116 On-site wiring 118 Outlet 120, 220 Power supply facility 120b Control unit 224 Ammeter

Claims (2)

An electric power system that supplies electric power from an electric power system to a load facility through premises wiring,
A power supply facility connected to the premises wiring;
A circuit breaker having a breaking capacity obtained by subtracting the maximum capacity of the power supply facility from the breaking capacity of the circuit breaker connected to the campus wiring and connected to the campus wiring before the power supply facility is connected;
An electric power system comprising: An electric power system that supplies electric power from an electric power system to a load facility through premises wiring,
A power supply facility connected to the premises wiring;
A circuit breaker connected to the premises wiring, having a breaking capacity obtained by subtracting the maximum capacity of the power supply facility from the overcurrent withstand capability of the premises wiring;
An electric power system comprising:

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