JP2010213384A - Distributed power supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To link multiple household distributed power supplies to a power system at low cost. <P>SOLUTION: A large-scale photovoltaic power generating system 1 is connected to a linkage point 3 in a power system 2 and a circuit breaker 4 is placed between the system and the linkage point 3. In the photovoltaic power generating system 1, the following operation is carried out: multiple direct-current powers from the photovoltaic power generators G1 at individual homes are converted into an alternating-current power in a lump by an inverter I1 and the alternating-current power is boosted by a transformer T2 and a transformer T1, and the boosted alternating-current power is supplied to the power system 2; a direct-current power from the photovoltaic power generator G2 at each home is converted into an alternating-current power by the inverter I2 at each home and the resulting multiple alternating-current powers are boosted in a lump by a transformer T3 and the transformer T1, and each boosted alternating-current power is supplied to the power system 2; and a direct-current power from a storage battery C is converted into an alternating-current power by an inverter I3 and the alternating-current power is boosted by a transformer T4 and the transformer T1, and the boosted alternating-current power is supplied to the power system 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a distributed power supply system using a home distributed power supply.

Currently, home photovoltaic power generation systems are linked to the power grid from homes via distribution lines. However, if a large number of grids are linked to the power grid in the future, voltage increases and fluctuations will occur. It is expected that problems such as difficulty in detecting an isolated operation will become apparent.
On the other hand, there is a method of introducing a voltage regulator, a power electronics device, or a storage battery as a measure for suppressing voltage rise, fluctuation, harmonics, and the like. In addition, as a measure to detect isolated operation, the isolated operation prevention device added to each household photovoltaic power generation system has a higher function than the conventional one, and the transfer is cut off based on the circuit breaker information of the substation. Some methods have been proposed and already commercialized. Patent Document 1 discloses a distributed power supply isolated operation detection system that can reliably detect a power failure in a distribution system and can reliably prevent a distributed power supply isolated operation.

JP 2007-259660 A

However, the conventional method has a problem that it is expensive because it is necessary to take an individual measure for each home-use solar power generation system for detecting an isolated operation. In addition, voltage rises, fluctuations, harmonics, etc. are difficult to control because they are distribution lines with a low voltage class, such as 6.6 kV. There is a disadvantage that it appears prominently.
The present invention has been made in view of the above problems, and a main object thereof is to link a plurality of home-use distributed power sources to a power system at low cost.

In order to solve the above-described problems, the present invention is a distributed power supply system that is installed in a home and receives direct-current power from a plurality of distributed power supplies that generate direct-current power and receive power. An inverter that converts DC power into AC power; and a transformer that receives AC power from the inverter, boosts the received AC power, and supplies the AC power to the power system.
According to this configuration, a plurality of household distributed power sources can be combined and linked to the power system at low cost via the inverter and the transformer. In addition, by converting DC power to AC power and boosting the converted AC power, it can be directly connected to the power system at a high voltage class, so voltage increases and fluctuations due to distributed power sources, harmonics Etc. can be reduced. The transformer corresponds to the transformers T1 and T2 in the embodiment.

The present invention is a distributed power supply system, wherein the transformer receives AC power from the plurality of inverters, and boosts the received AC power, and the plurality of the first power sources. A second transformer that receives the AC power boosted from the transformer, further boosts the received AC power, and supplies the AC power to the power system.
According to this configuration, since a plurality of inverters are connected to the first transformer and a plurality of first transformers are connected to the second transformer, a hierarchical connection configuration is adopted, so that the routing of the lines is efficient. Therefore, the overall line length can be shortened, and the number of transformers can be reduced by raising the voltage collectively. The first transformer and the second transformer correspond to the transformers T2 and T1 in the embodiment, respectively.

Further, the present invention is a distributed power system, which is installed in a home and generates DC power, receives DC power from the distributed power, and converts the received DC power into AC power An inverter, a transformer that receives AC power from the plurality of inverters, boosts the received AC power and supplies the received AC power to an electric power system, and a plurality of the inverters and an electric wire that connects the transformers. It is characterized by.
According to this configuration, a plurality of household distributed power sources can be combined and linked to the power system at low cost via the inverter and the transformer. In addition, by converting DC power to AC power and boosting the converted AC power, it can be directly connected to the power system at a high voltage class, so voltage increases and fluctuations due to distributed power sources, harmonics Etc. can be reduced. And when the electric wire which connects an inverter and a transformer passes a long distance, since alternating current power is passed through the electric wire, the problem of the interruption | blocking and safety | security at the time of letting direct current power pass can be solved. The transformer corresponds to the transformers T1 and T3 in the embodiment.

The present invention is a distributed power supply system, wherein the transformer receives AC power from the plurality of inverters, and boosts the received AC power, and the plurality of the first power sources. A second transformer that receives the AC power boosted from the transformer, further boosts the received AC power, and supplies the AC power to the power system.
According to this configuration, since a plurality of inverters are connected to the first transformer and a plurality of first transformers are connected to the second transformer, a hierarchical connection configuration is adopted, so that the routing of the lines is efficient. Therefore, the overall line length can be shortened, and the number of transformers can be reduced by raising the voltage collectively. The first transformer and the second transformer correspond to the transformers T3 and T1 in the embodiment, respectively.

Moreover, the present invention is a distributed power supply system, wherein the transformer or the second transformer is connected to the power system via one circuit breaker.
According to this configuration, it is possible to detect and prevent an isolated operation by installing one circuit breaker between the power system and the transformer.

  In addition, the problems disclosed by the present application and the solutions thereof will be clarified by the description of the embodiments and the drawings.

  According to the present invention, it is possible to link a plurality of household distributed power sources to a power system at low cost.

1 is a diagram illustrating a configuration of a large-scale solar power generation system 1. FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. A photovoltaic power generation system (distributed power supply system) according to an embodiment of the present invention connects a plurality of household photovoltaic power generation devices (distributed power supply) to one large power conditioner (inverter), and a plurality of large sized power conditioners (inverters). The power conditioner group functions as one large-scale solar power plant. The connection points of the power system are connected to the power system not only at the 6.6 kV distribution line but also at places where the voltage class is higher than the 6.6 kV distribution line, such as the 22 kV distribution line, the 66 kV distribution line, and the 110 kV distribution line.

  In addition, the power conditioner plays a very important role in the photovoltaic power generation system, and converts the DC power generated by the photovoltaic power generation device into AC power so that it can be used at home, and adjusts the voltage. Etc.

≪System configuration and overview≫
FIG. 1 is a diagram illustrating a configuration of a large-scale photovoltaic power generation system 1. The large-scale solar power generation system 1 is a large-scale power generation system using a household solar power generation device, and is connected to a connection point 3 of the power system 2, and a breaker 4 is connected to the connection point 3. It is installed. The power system 2 transmits power at a voltage of 22 kV, 66 kV, 110 kV, or the like. The circuit breaker 4 stops power supply from the large-scale solar power generation system 1 when power transmission in the power system 2 is stopped, and is realized by an isolated operation prevention device, a transfer interruption device, or the like.

  As shown in FIG. 1, the large-scale solar power generation system 1 includes transformers T1 to T4, electric wires L1 to L7, inverters I1 to I3, solar power generation devices G1 and G2, and a storage battery C.

  First, a connection configuration and an outline will be described. The transformer T1 is connected to the power system 2 at the interconnection point 3 through the circuit breaker 4, and is connected to the transformers T2 to T4 through the electric wire L1. The transformer T2 is connected to the transformer T1 through the electric wire L1, while being connected to the inverter I1 through the electric wire L2. Inverter I1 is connected to photovoltaic power generation device G1 through electric wire L3 and electric wire L4 connected to electric wire L3. The transformer T3 is connected to the transformer T1 through the electric wire L1, and is connected to the inverter I2 through the electric wire L5, the electric wire L6 connected to the electric wire L5, and the electric wire L7 connected to the electric wire L6. The inverter I2 is connected to the solar power generation device G2. The transformer T4 is connected to the transformer T1 through the electric wire L1, while being connected to the inverter I3. Inverter I3 is connected to storage battery C.

  For example, the transformers T1 to T4 and the inverter I1 are installed in a vacant space in a residential area or underground, but may be arranged in a distributed manner. The inverter I1 is a large DC / AC converter. The inverter I2 is a DC / AC converter installed in each home. The inverter I3 is a DC / AC converter installed near the storage battery C. The solar power generation devices G1 and G2 are power generation devices using sunlight that are installed in each home. The electric wires L1, L2, L5, L6, and L7 are electric wires that pass AC power. The electric wires L3 and L4 are dedicated lines through which DC power passes, and are provided along existing distribution lines or buried underground. The electric wires L3 and L4 that connect the inverter I1 and the solar power generation device G1, and the electric wires L5, L6, and L7 that connect the transformer T3 and the solar power generation device G2 are both long distances. .

≪Function of equipment≫
Next, functions of each device will be described.
The transformer T1 boosts the voltage of 6.6 kV received through the electric wire L1 to a voltage of 22 kV, 66 kV, or 110 kV and supplies the boosted voltage to the power system 2.

  The transformer T2 boosts the voltage of 200 to 400 V received through the electric wire L2 to a voltage of 6.6 kV, and supplies the voltage to the transformer T1 through the electric wire L1. The inverter I1 converts direct current power received through the electric wire L4 into alternating current power, and supplies the alternating current power to the transformer T2 through the electric wire L2. The plurality of solar power generation devices G1 generate DC power and supply it to the inverter I1 through the electric wire L4. In other words, a plurality of DC power from the solar power generation devices G1 in each household are collectively converted into AC power by the inverter I1, and the AC power is boosted by the transformer T2 and the transformer T1 and boosted AC power. Is supplied to the electric power system 2.

  The transformer T3 boosts the voltage of 200 to 400 V received through the electric wires L5, L6, and L7 to a voltage of 6.6 kV, and supplies the voltage to the transformer T1 through the electric wire L1. The inverter I2 converts the DC power received from the solar power generation device G2 into AC power, and supplies the AC power to the transformer T3 through the electric wires L7, L6, and L5. The solar power generation device G2 generates DC power and supplies it to the inverter I2. In other words, the DC power from the photovoltaic power generation device G2 of each household is converted into AC power by the inverter I2 of each household, and a plurality of the AC power is boosted by the transformers T3 and T1 and boosted. AC power is supplied to the power system 2.

  The transformer T4 boosts the voltage of 200 to 400 V received from the inverter I3 to a voltage of 6.6 kV and supplies the voltage to the transformer T1 through the electric wire L1. The inverter I3 is a DC / AC converter, converts DC power received from the storage battery C into AC power, and supplies the AC power to the transformer T4. The storage battery C stores surplus power during peak hours in the daytime and supplies it to the inverter I3 as necessary when it does not generate power at night or during periods of no sunlight. In other words, the DC power from the storage battery C is converted into AC power by the inverter I3, the AC power is boosted by the transformers T4 and T1, and the boosted AC power is supplied to the power system 2. According to this, load leveling, output fluctuation suppression, planned operation, and the like can be performed by providing the storage battery C together.

  As described above, the large-scale photovoltaic power generation system 1 has a hierarchical connection configuration, so that the routing of the lines becomes efficient, and the number of transformers can be reduced by raising the voltage collectively, which is economical. By combining the lines, the entire line length can be shortened to suppress problems such as voltage drop, interruption, system protection, and the like.

  According to the embodiment of the present invention described above, in the connection configuration relating to the photovoltaic power generation apparatuses G1 and G2, the plurality of inverters I1 and I2 are connected to the transformers T2 and T3, respectively, and the plurality of transformers T2 and T3 are connected. Is connected to the transformer T1, the overall line length can be shortened by efficient routing, and the number of transformers can be reduced by increasing the voltage collectively. Moreover, since not only the 6.6 kV distribution line but also the 22 k, 66 kV distribution line, 110 kV connection line, etc., the voltage system is directly connected to the power system 2 at a higher voltage class than the 6.6 kV distribution line, It is possible to reduce the influence of voltage rise and fluctuation, harmonics, and the like due to G2.

  Next, according to the connection configuration related to the solar power generation device G1, since one inverter I1 is provided for the plurality of solar power generation devices G1, it is not necessary to provide an inverter in each home, and the cost is low and efficient. It is.

  And according to the connection configuration relating to the solar power generation device G2, the electric wires L7, L6 and L5 connecting the inverter I2 and the transformer T3 are long distances, and the AC power is passed through these electric wires, so that it is easy to cut off, Safety can be improved.

  Moreover, regarding the isolated operation detection, both the isolated operation preventing device and the transfer blocking device can be employed. The isolated operation prevention device has been conventionally installed in each of the photovoltaic power generation devices G1 and G2, but it may be installed in the vicinity of the interconnection point 3. Also, only one transfer blocking device may be installed so as to block the interconnection point 3.

  Although it is difficult to install a mega solar in an urban area or the like, the large-scale photovoltaic power generation system 1 uses household photovoltaic power generation devices G1 and G2, so that it can also be installed in a dense residential area. For example, it can be systematically arranged in a new town or the like to be developed.

<< Other embodiments >>
As mentioned above, although the form for implementing this invention was demonstrated, the said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention. For example, the following embodiments can be considered.

(1) A business model in which the installation, maintenance, and the like of the solar power generation devices G1 and G2 in each home are performed by an electric power company, a local government, or an operating company established by a citizen who installed the solar power generation devices G1 and G2 can be considered. As a business model when an electric power company performs installation and maintenance, each household that considers the large-scale solar power generation system 1 as one of the power stations operated by the electric power company and provides the installation place of the solar power generation devices G1 and G2 It is conceivable to use the solar power generation devices G1 and G2 by paying a rent to the vehicle.
(2) In the above embodiment, the home solar power generation device is used as a distributed power source, but other distributed power sources such as a wind power generation device and a fuel cell may be used.

1 Large-scale photovoltaic power generation system (distributed power supply system)
2 Power system 3 Interconnection point 4 Breaker C Storage battery G1, G2 Photovoltaic power generation device (distributed power supply)
I1-I3 Inverter L1-L7 Electric wire T1-T4 Transformer

Claims (5)

Distributed power source installed at home and generating DC power,
An inverter that receives DC power from the plurality of distributed power sources, and converts the received DC power into AC power;
A transformer that receives AC power from the inverter, boosts the received AC power, and supplies the AC power to the power system;
A distributed power supply system comprising: The distributed power supply system according to claim 1,
The transformer is
A first transformer that receives AC power from the plurality of inverters and boosts the received AC power;
A second transformer that receives the boosted AC power from a plurality of the first transformers, further boosts the received AC power, and supplies the boosted AC power to the power system;
A distributed power system characterized by comprising: Distributed power source installed at home and generating DC power,
An inverter that receives DC power from the distributed power source and converts the received DC power into AC power;
A transformer that receives AC power from the plurality of inverters, boosts the received AC power, and supplies the AC power to the power system;
A plurality of inverters and an electric wire connecting the transformer;
A distributed power supply system comprising: The distributed power supply system according to claim 3,
The transformer is
A first transformer that receives AC power from the plurality of inverters and boosts the received AC power;
A second transformer that receives the boosted AC power from a plurality of the first transformers, further boosts the received AC power, and supplies the boosted AC power to the power system;
A distributed power system characterized by comprising: A distributed power supply system according to any one of claims 1 to 4,
The transformer or the second transformer is:
A distributed power supply system that is linked to the power system via one circuit breaker.

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