KR20220081576A - DC distribution network design apparatus - Google Patents

Abstract

The present invention relates to an apparatus for designing a DC (Direct Current) distribution network forming a microgrid cluster.
DC distribution network design device according to a preferred embodiment of the present invention is 1) a plurality of supplier microgrids (MG1-1, MG2-1, ..., MGn-1) each system connection point (P1-1, P2-) 1, ..., Pn-1) geographic coordinates 2) Multiple user microgrids (MG1-2, MG2-2, ..., MGn-2), respectively, grid connection points (P2-1, P2-2) , ..., Pn-2) geolocation coordinates 3) Annual power generation information of each of a plurality of provider microgrids (MG1-1, MG2-1, ..., MGn-1) 4) A plurality of user microgrids ( MG1-2, MG2-2, ..., MGn-2) an MG information input unit 310 for receiving each year's load information; and an MG-to-MG line setting unit ( 320).

Description

DC distribution network design apparatus

The present invention relates to an apparatus for designing a DC (Direct Current) distribution network forming a microgrid cluster.

DC (Direct Current) distribution technology is more economical than AC because the insulation class of the line is lower, and it is possible to reduce the cost of line construction because there are at least one phase less than AC for transmission. In addition, the DC power distribution technology does not have an alternating component (frequency), so there is no reactance component, so reactive power is not generated and a skin effect is not generated.

In simple comparison, DC transmission has advantages over AC transmission in terms of higher transmission capacity, reduced transmission loss, less environmental impact, and reduced investment cost.

In recent years, interest in DC power distribution networks that can compensate for the shortcomings of the existing AC power distribution network and increase efficiency is increasing due to the increase in DC-based distributed power, the use of energy storage devices, and the construction of microgrids.

Micro Grid is similar to Smart Grid in that information technology is applied to the power grid to control the amount of power generation, and it requires functions such as generation and consumption forecasting, but its application scale is lower than that of the smart grid. The difference is that large-scale power transmission facilities are not required because it is relatively small and the location of the power generation source and consumer (power consuming subject) is close.

The US Department of Energy (DOE) defines a micro grid as follows.

It is a group of 'consumer' and 'Distributed Energy Resource (DER)' interconnected within a clearly defined electrical range, and is a controllable entity with respect to the system, and can be connected and independent from the system.

The concept of microgrids is expanding. In addition to the form in which the consumer and DER are fused (supply type MG), 1) the form in which only the consumer exists (demand type MG) 2) the form in which only residual energy resources exist 3) 1) and 2) ESS (Energy Storage System) ) is a fused form.

Recently, attempts have been made to connect microgrids to DC power distribution networks. In this case, the microgrid may be configured as a MVDC (Medium Voltage Direct Currnet) system, and the inside of the microgrid may be configured as an LVDC (Low Voltage Direct Currnet) system.

KR10-2017-0138178 (Application date: 2017.10.24) KR10-2013-0123408 (filed date: 2013.10.16)

An object of the present invention is to provide an apparatus for designing a DC power distribution network (MVDC distribution network) connecting microgrids.

DC distribution network design apparatus according to a preferred embodiment of the present invention is 1) a plurality of supplier microgrids (MG1-1, MG2-1, ..., MGn-1) each system connection point (P1-1, P2-) 1, ..., Pn-1) geographic coordinates 2) Multiple user microgrids (MG1-2, MG2-2, ..., MGn-2), respectively, grid connection points (P2-1, P2-2) , ..., Pn-2) geolocation coordinates 3) Annual power generation information of each of a plurality of provider microgrids (MG1-1, MG2-1, ..., MGn-1) 4) A plurality of user microgrids ( MG1-2, MG2-2, ..., MGn-2) an MG information input unit 310 for receiving each year's load information; and an MG-to-MG line setting unit ( 320).

Here, the DC distribution network design device determines ESS geographic location coordinates at which the sum of distances with a plurality of direct lines is the minimum, and determines the ESS geographic location coordinates and a plurality of direct lines corresponding to the determined ESS geographic location coordinates. It may further include an ESS coordinate setting unit 330 for generating an indirect line connecting the points in each.

And, the DC power distribution network design device generates a daily excess supply curve between the supplier microgrid and the user microgrid directly connected to each other by a line, and sums up all of the excess supply curve matching a plurality of direct lines per day for a year and calculates the sum of 'supply-consumption' for each sustain period from the summed supply curve, selects a continuous period that provides the maximum sum of 'supply-consumption' during the year, and in the selected continuous period It may further include an ESS capacity setting unit 340 for setting the sum of 'supply-consumption' of 'to the capacity of the ESS.

The present invention can automatically set the DC power distribution network (MVDC distribution network) connecting the microgrids in terms of direct lines, indirect lines, ESS geographic location coordinates, ESS capacity, and line capacity.

1 shows a microgrid cluster to which the present invention is applied.
FIG. 2 is a functional block diagram of the integrated operating device of FIG. 1 .
3 is a functional block diagram of an apparatus for designing a DC power distribution network according to a preferred embodiment of the present invention.
4 shows an example of a daily excess supply curve.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing each figure, like reference numerals have been used for like elements. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention.

The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, a DC distribution network design apparatus according to a preferred embodiment of the present invention will be described with reference to FIGS. 1 to 4 . Hereinafter, in order to clarify the gist of the present invention, descriptions of previously known matters will be omitted or simplified.

* Microgrid Cluster Structure *

Hereinafter, a distribution network structure of a microgrid cluster to be designed by the DC distribution network design apparatus of the present invention will be described.

First, the microgrid cluster consists of a plurality of provider microgrids (MG1-1, MG2-1, ..., MGn-1), and a plurality of user microgrids (MG1-2, MG2-2, ..., MGn-2). ) may be included. The number of the plurality of supplier microgrids (MG1-1, MG2-1, ..., MGn-1) and the number of the plurality of user microgrids (MG1-2, MG2-2, ..., MGn-2) are assumed to be the same.

The first supplier microgrid MG1-1 may be a microgrid with the largest annual power supply in the plurality of supplier microgrids. The second supplier microgrid MG2-1 may be a microgrid with the second largest annual power supply in the plurality of supplier microgrids. The nth supplier microgrid MGn-1 may be a microgrid with the nth largest annual power supply in a plurality of supplier microgrids.

The first consumer microgrid MG1 - 2 may be a microgrid with the highest annual power consumption among a plurality of consumer microgrids. The second consumer microgrid MG2-2 may be a microgrid having the second largest annual power consumption among the plurality of consumer microgrids. The nth consumer microgrid MGn-2 may be a microgrid having the nth largest annual power consumption in a plurality of consumer microgrids.

The plurality of provider microgrids (MG1-1, MG2-1, ..., MGn-1) have the role of power providers in the microgrid cluster, and the plurality of user microgrids (MG1-2, MG2-2, .. ., MGn-2) may have the role of power consumer. Each of the plurality of supplier microgrids (MG1-1, MG2-1, ..., MGn-1) may have a grid connection point (P1-1, P2-1, ..., Pn-1). Each of the plurality of user microgrids MG1-2, MG2-2, ..., MGn-2 may have a system connection point P2-1, P2-2, ..., Pn-2. Through the grid connection point, a plurality of supplier microgrids and a plurality of user microgrids can be connected to the MVDC distribution network. The MVDC distribution network may be a DC grid with a grid DC voltage of 1.5 kV to 100 kV. 1, the MCDC distribution network is a first direct line (L1-1), a first indirect line (L1-2), a second direct line (L2-1), a second indirect line (L2-2), ... , an nth direct line Ln-1, and an nth indirect line Ln-2.

The first direct line L1-1 may be an MVDC distribution line connecting the system connection point P1-1 of the first supplier microgrid and the system connection point P1-2 of the second user microgrid with the shortest distance. The first indirect line L1 - 2 may be an MVDC distribution line connecting the first direct line L1-1 and the ESS 100 .

The second direct line L2-1 may be an MVDC distribution line connecting the system connection point P2-1 of the second supplier microgrid and the system connection point P2-2 of the second user microgrid with the shortest distance. The second indirect line L2 - 2 may be an MVDC distribution line connecting the second direct line L2-1 and the ESS 100 .

The nth direct line Ln-1 may be an MVDC distribution line connecting the system connection point Pn-1 of the nth supplier microgrid and the system connection point Pn-2 of the nth user microgrid with the shortest distance. The nth indirect line Ln-2 may be an MVDC distribution line connecting the nth direct line Ln-1 and the ESS 100 .

That is, the number of multiple supplier microgrids and multiple user microgrids is the same, and the shortest direct line between the supplier microgrid and the user microgrid in which the annual power supply ranking of the supplier microgrid and the annual power consumption rank of the user microgrid are the same can be connected to the street. This is to minimize power loss in the MVDC distribution network by matching the power supply scale of the supplier microgrid with the power consumption scale of the consumer microgrid and direct power supply from the supplier microgrid to the consumer microgrid in the shortest distance. to be.

In addition, the ESS 100 may be connected to a plurality of direct lines interconnecting a plurality of supplier microgrids and a plurality of user microgrids through a plurality of indirect lines. In this case, the ESS 100 may be installed at a geographic location where the sum of the lengths of the plurality of indirect lines is minimized. Accordingly, the length of the indirect line for supplying power to a plurality of user microgrids using the ESS 100 can be minimized. Thereby, the construction cost for the MVDC distribution network can be minimized. Of course, by matching the power supply scale of the supplier microgrid with the power consumption scale of the consumer microgrid and direct power supply from the supplier microgrid to the consumer microgrid in the shortest distance, the construction cost of the MVDC distribution network can be minimized. have.

A 1-1 meter M 1-1 may be installed on the first direct line L1-1. The 1-1 meter M 1-1 may measure the amount of power directly supplied to the first user microgrid MG 1-2 through the first direct line L1-1. The 1-1 measuring instrument M 1-1 may be installed on the side of the system connection point P1-2 of the first user microgrid.

The first indirect line L1 - 2 may be provided with a first - second measuring instrument ( M 1-2 ). The 1-2 measuring instrument M 1-2 may measure the amount of power supplied by the ESS 100 to the first user microgrid MG 1-2 through the first indirect line L1-2.

The second direct line L2-1 may be provided with a 2-1 meter M 2-1. The second-first measuring instrument M 2-1 may measure the amount of power directly supplied to the second user microgrid MG 2-2 through the second direct line L2-1. The 2-1-th measuring instrument M 2-1 may be installed on the side of the system connection point P2-2 of the second user microgrid.

A 2-2 meter M 2 - 2 may be installed on the second indirect line L2 - 2 . The 2-2 meter M 2 - 2 may measure the amount of power supplied by the ESS 100 to the second user microgrid MG 2 - 2 through the second indirect line L2 - 2 .

An n-1 th meter M n - 1 may be installed on the n th direct line Ln-1. The n-1 th measuring instrument M n-1 may measure the amount of power directly supplied to the n th user microgrid MG n-2 through the n th direct line Ln-1. The n-1 th measuring instrument M n-1 may be installed on the side of the grid connection point Pn-2 of the n th user microgrid.

An n-2 th meter M n - 2 may be installed on the n th indirect line Ln - 2 . The n-2 th meter M n - 2 may measure the amount of power supplied by the ESS 100 to the n th user microgrid MG n-2 through the n th indirect line Ln-2.

That is, the instrument may be installed in each of the direct lines connecting between the plurality of supplier microgrids and the plurality of user microgrids. A measuring instrument installed in the direct line can measure the amount of power supplied to the user microgrid connected to the direct line. In addition, a measuring instrument may be installed in each of the indirect lines connecting the ESS 200 to each of the plurality of direct lines. A measuring instrument installed on each indirect line can measure the amount of power supplied by the ESS 200 to the user microgrid connected via the indirect line and the direct line through the indirect line.

ESS 100 is a plurality of indirect lines (L1-2) to a plurality of direct lines (L1-1, L2-1, ..., Ln-1) interconnecting a plurality of supplier microgrids and a plurality of user microgrids , L2-2, ..., Ln-2). In this case, the ESS 100 may be installed at a geographic location where the sum of the lengths of the plurality of indirect lines L1-2, L2-2, ..., Ln-2 is the minimum.

Such a microgrid cluster may be operated by the integrated operating device (TOC, 200). Of course, each of the plurality of provider microgrids and the plurality of user microgrids belonging to the microgrid cluster may perform an operation operation by EMS (Energy Management Storage) installed therein. Hereinafter, matters related to power transaction in the integrated operation device 200 will be mainly described.

The integrated operation device 200 may include a power amount collection unit 210 and a power transaction settlement unit 220 .

The amount of power collection unit 210 is installed in the direct line measuring instruments (M 1-1, M 2-1, ..., M n-1) and indirectly installed in the line measuring instruments (M 1-2, M 2-2, . .., M n-2) may be collected in a first preset period.

The power transaction settlement unit 220 may calculate the power purchase cost in a preset second cycle according to the following Equation 1 based on the collected power amount. Here, the second period may be the same as the first period.

[Equation 1]

Power purchase cost = direct purchase cost + indirect purchase cost

here,

Direct purchase cost: The cost for the amount of electricity that the user microgrid receives directly from the supplier microgrid through a direct line connected to the user microgrid

Indirect purchase cost: The cost for the amount of electricity that the user microgrid receives from the ESS through the indirect line connected to the user microgrid through the direct line.

When calculating the power purchase cost, the power transaction settlement unit 220 converts the amount of power that the user microgrid directly receives from the supplier microgrid through the direct line connected to the user microgrid from the amount of power measured by the instrument installed in the direct line to the indirect line. It can be calculated by subtracting the amount of power measured by the installed measuring instrument. In addition, the power transaction settlement unit 2200 may calculate the direct purchase cost by multiplying the unit power direct purchase cost by the amount of power the user microgrid receives directly from the supplier microgrid through a direct line connected to the user microgrid.

When calculating the power purchase cost, the power transaction settlement unit 220 may determine the amount of power supplied from the ESS through the indirect line where the user microgrid is connected to the user microgrid via a direct line through a meter installed in the indirect line. At this time, the power transaction settlement unit 220 calculates the indirect purchase cost by multiplying the unit power indirect purchase cost by the amount of power supplied from the ESS through the indirect line connected to the user microgrid and the direct line through the user microgrid. can

Here, the unit power indirect purchase cost may be calculated by Equation 2 below.

[Equation 2]

Unit power indirect purchase cost = unit power direct purchase cost + (indirect line length * additional cost per indirect line unit length)

The indirect line length may be the length of an indirect line connected through a direct line to a user microgrid subject to additional power purchase cost. By reflecting the additional cost for the length of the indirect line connected to the user microgrid through the direct line in the power purchase cost settlement, the investment cost associated with the construction of the MVDC distribution network is equally recovered from a plurality of user microgrids can do.

* DC distribution network design device *

Hereinafter, an apparatus for designing the DC power distribution network described in FIGS. 1 and 2 will be described.

The DC power distribution network design device 300 may be a PC in which a design program is embedded. The DC distribution network design device 300 includes an MG information input unit 310, an inter-MG line setting unit 320, an ESS coordinate setting unit 330, an ESS capacity setting unit 340, a line capacity setting unit 350, and a user. It may include an interface 360 .

The MG information input unit 310 may receive the following information.

1. Geolocation coordinates of each grid connection point (P1-1, P2-1, ..., Pn-1) of a plurality of supplier microgrids (MG1-1, MG2-1, ..., MGn-1)

2. Geolocation coordinates of each grid connection point (P2-1, P2-2, ..., Pn-2) of a plurality of user microgrids (MG1-2, MG2-2, ..., MGn-2)

3. Annual power generation information of each of multiple supplier microgrids (MG1-1, MG2-1, ..., MGn-1)

4. Annual load information of each user microgrid (MG1-2, MG2-2, ..., MGn-2)

In this case, the number of input plurality of supplier microgrid and the number of plurality of user microgrid may be the same.

The MG line setting unit 320 analyzes the annual power generation information of each of the plurality of supplier microgrids (MG1-1, MG2-1, ..., MGn-1), and the average annual power generation amount of the plurality of supplier microgrids ranking can be determined. In addition, the inter-MG line setting unit 320 may determine the annual average power consumption ranking by analyzing the annual load information of each of the plurality of user microgrids (MG1-2, MG2-2, ..., MGn-2). .

And, the inter-MG line setting unit 320 is a direct connection between the grid connection point of the supplier microgrid and the grid connection point of the user microgrid, in which the annual average power generation ranking of the supplier microgrid and the annual average power consumption ranking of the user microgrid are the same. line can be created.

In addition, the ESS coordinate setting unit 330 may determine the ESS geographic location coordinates at which the sum of distances to a plurality of direct lines is the minimum. The ESS coordinate setting unit 330 may determine the geographic location coordinates of the ESS at which the sum of the distances to the plurality of direct lines is the minimum by using an objective function using the coordinates in each of the plurality of direct lines as variables. In addition, the ESS coordinate setting unit 330 may generate an indirect line connecting the determined ESS geographic location coordinates and points in each of a plurality of direct lines corresponding to the geographic location coordinates. At this time, the user interface 360 1) a plurality of supplier microgrids (MG1-1, MG2-1, ..., MGn-1) each of the system connection points (P1-1, P2-1, ..., Pn) Marker of -1) and its coordinates 2) Multiple user microgrids (MG1-2, MG2-2, ..., MGn-2) Each system connection point (P2-1, P2-2, ..., Pn) -2) markers and their coordinates 3) a plurality of direct and indirect lines 4) ESS markers and coordinates 5) coordinates of direct lines connected to indirect lines, etc. can be displayed.

The ESS capacity setting unit 340 may generate a daily excess supply curve between the supplier microgrid and the user microgrid that are directly connected to each other by a line. The daily excess supply curve may be a graph of the amount of electricity obtained by subtracting consumption from supply for a day. In this case, the daily excess supply curve may be directly generated for each line.

4 shows an example of an excess supply curve. In FIG. 4 , a region in which ‘amount of supply-consumption’ is ‘a region of oversupply’ may be an area in which ‘amount of supply-consumption’ is ‘a region of undersupply. And, the period in which ‘supply-consumption’ is ‘continuous’ is called a continuous period. In the region where 'supply-consumption' is ', the ESS 100 may store a portion of supply that exceeds consumption. 4 illustrates that there are two duration intervals.

The ESS capacity setting unit 340 may add up all of the excess supply curves matching a plurality of direct lines by day for one year. In addition, the ESS capacity setting unit 340 may calculate the sum of 'supply-consumption' during the sustain period for each sustain period in the summed supply curve. In addition, the ESS capacity setting unit 340 may select a duration that provides the sum of the maximum 'supply amount-consumption' during the year. And, the ESS capacity setting unit 340 may set the total of 'supply amount-consumption' in the selected continuous period as the capacity of the ESS. By setting the ESS capacity in this way, in a microgrid cluster consisting of a plurality of supplier microgrids and a plurality of user microgrids, the ESS can sufficiently support supply and demand balancing through charging and discharging. Thereby, the energy independence of the microgrid cluster can be increased. The set ESS capacity may be displayed through the user interface 360 .

The line capacity determining unit 350 may specify the microgrid having the maximum load during the year by using the annual load amount information of each of the plurality of user microgrids MG1-2, MG2-2, ..., MGn-2. . And, it is possible to calculate the MVDC distribution current corresponding to the maximum load in the microgrid. In addition, the line capacity determining unit 360 may set a value obtained by multiplying the calculated MVDC distribution current by a margin coefficient (eg, 1.2) as the maximum allowable current. And, the line capacity may be determined by multiplying the maximum allowable current by a preset MVDC distribution voltage (eg, 10 kV).

MG1-1, MG2-1, ..., MGn-1 : Supplier microgrid
MG1-2, MG2-2, ..., MGn-2 : User microgrid
L1-1, L2-1, Ln-1: direct line
L1-2, L2-2, Ln-2 : Indirect line
P1-1, P1-2, P2-1, P2-2, Pn-1, Pn-2: grid connection point
M1-1, M1-2, M2-1, M2-2, Mn-1, Mn-2: instrument
100: ESS
200: integrated operating unit
300: DC distribution network design device

Claims (3)

1) Geolocation coordinates of each grid connection point (P1-1, P2-1, ..., Pn-1) of a plurality of supplier microgrids (MG1-1, MG2-1, ..., MGn-1) 2 ) Geolocation coordinates of each grid connection point (P2-1, P2-2, ..., Pn-2) of a plurality of user microgrids (MG1-2, MG2-2, ..., MGn-2) 3) Annual power generation information for each of the multiple supplier microgrids (MG1-1, MG2-1, ..., MGn-1) 4) Multiple user microgrids (MG1-2, MG2-2, ..., MGn-2) ) MG information input unit 310 for receiving each year's load information; and
A line setting unit (320) between the MGs that creates a direct line connecting the grid connection point of the supplier microgrid and the grid connection point of the user microgrid, in which the annual average power generation rank of the supplier microgrid and the annual average power consumption rank of the user microgrid are the same. ), including a DC distribution network design device. The method of claim 1,
An ESS geographic location coordinate at which the sum of distances with a plurality of direct lines is the minimum is determined, and an indirect line connecting the determined ESS geographic location coordinates and a point on each of a plurality of direct lines corresponding to the determined ESS geographic location coordinates DC distribution network design device, characterized in that it further comprises an ESS coordinate setting unit 330 to generate a. The method of claim 1,
generate daily excess supply curves between supplier microgrids and user microgrids connected by direct lines to each other;
Sum all oversupply curves matching multiple direct lines per day for a year,
Calculating the sum of 'supply-consumption' during the duration for each duration in the summed supply curve,
Choose a duration that provides the maximum sum of 'supply-consumption' during the year;
DC distribution network design device, characterized in that it further comprises an ESS capacity setting unit (340) for setting the sum of 'supply-consumption' in the selected continuous period as the capacity of the ESS.

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