JP6672203B2 - Power supply path evaluation device, power supply path evaluation method, and program - Google Patents

Description

  An embodiment of the present invention relates to a power supply path evaluation device, a power supply path evaluation method, and a program.

  A power transmission and distribution system that transmits and distributes power includes various power distribution facilities. It is necessary to update these facilities systematically according to the use conditions and the years of use. In this connection, there is known a technique for evaluating the supply reliability of a plurality of system configurations of a power system in order to rationally plan a facility update. However, in the related art, there are cases where it is not possible to efficiently make a plan for updating power equipment.

JP 2004-242411 A

  The problem to be solved by the present invention is to provide a power supply path evaluation device, a power supply path evaluation method, and a program that can efficiently make an update plan for power equipment.

  The power supply path evaluation device according to the embodiment has a first selection unit, a derivation unit, and a second selection unit. The first selection unit selects one or more power supply paths from among a plurality of power supply paths configuring the power system, in which an index value based on the number of power failures occurring in a predetermined period is equal to or less than a threshold. The deriving unit derives an electrical state of the power supply path selected by the first selecting unit. The second selection unit selects a power supply path that satisfies a predetermined condition from one or more power supply paths selected by the first selection unit based on the electrical state derived by the derivation unit.

FIG. 1 is a diagram illustrating an example of a configuration of a power supply path evaluation device 100 according to an embodiment. The figure which shows typically the electric power system which the electric power system configuration information 132 shows. 5 is a flowchart illustrating an example of a flow of a series of processes performed by a control unit 110 according to the embodiment. The figure which shows an example of the graph structure of the binary decision graph used at the time of connection probability Pa calculation. The figure which shows an example of the frequency | count of failure occurrence for every transmission line. The figure which shows an example of the connection probability Pa of the electric power supply path | route PS calculated based on the frequency | count of failure occurrence for every transmission line PL illustrated in FIG. The figure which shows an example of the graph structure of the binary decision graph used at the time of SAIFI calculation. The figure which shows an example of the total number of customer facilities electrically connected with each load node ND. The figure which shows an example of SAIFI of each electric power supply path | route PS. The figure which shows an example of the power flow calculation result when the load condition A is given when stopping the transmission line PL1. The figure which shows an example of the power flow calculation result when the load condition B is given when stopping the transmission line PL1. The figure which shows an example of the power flow calculation result when the load condition C is given when stopping the transmission line PL1. The figure which shows an example of the power flow calculation result when the load condition A is given when stopping the electric wire PL3. The figure which shows an example of the power flow calculation result when the load condition B is given when stopping the transmission line PL3. The figure which shows an example of the power flow calculation result when the load condition C is given when stopping the transmission line PL3. The figure which shows an example of various electrical quantities in each load condition when stopping the transmission line PL1. The figure which shows an example of various electrical quantities in each load condition when stopping the transmission line PL3.

  Hereinafter, a power supply path evaluation device, a power supply path evaluation method, and a program according to an embodiment will be described with reference to the drawings. The power supply path evaluation device in the embodiment evaluates each of a plurality of power supply paths included in the power system and stops power supply to which power supply path when updating various power facilities included in the power system. It is a device that evaluates whether it is most reasonable to make it.

  FIG. 1 is a diagram illustrating an example of a configuration of a power supply path evaluation device 100 according to the embodiment. The power supply path evaluation device 100 of the present embodiment includes, for example, a control unit 110 and a storage unit 130.

  The control unit 110 includes, for example, a stopped facility candidate selection unit 112, a connection probability calculation unit 114, a first system configuration selection unit 116, a supply reliability calculation unit 118, a second system configuration selection unit 120, a system state, A deriving unit 122 and a third system configuration selecting unit 124 are provided. The first system configuration selection unit 116 is an example of a “third selection unit”, the second system configuration selection unit 120 is an example of a “first selection unit”, and the third system configuration selection unit 124 is This is an example of the “second selection unit”. The supply reliability calculation unit 118 is an example of an “index value calculation unit”.

  Some or all of the components of the control unit 110 may be realized by a processor such as a CPU (Central Processing Unit) executing a program stored in the storage unit 130. Some or all of the components of the control unit 110 may be realized by hardware such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array). It may be realized by cooperation of software and hardware.

  The storage unit 130 may be realized by, for example, a ROM (Read Only Memory), a flash memory, a HDD (Hard Disk Drive), an SD card, an MRAM (Magnetoresistive Random Access Memory), a RAM (Random Access Memory), a register, and the like. The storage unit 130 stores a program executed by the processor of the control unit 110, and also stores power system configuration information 132 and the like.

  FIG. 2 is a diagram schematically illustrating the power system indicated by the power system configuration information 132. The power system configuration information 132 is information indicating the number, types, connection paths, and the like of various power facilities and transmission lines (power lines) included in the power system. The power system in the present embodiment includes a transmission system and a distribution system. The power transmission system includes, for example, a power supply facility such as a power plant, a power transmission line that transmits power of an ultra-high voltage or an ultra-high voltage, a substation that transforms generated power, and the like. The power distribution system includes, for example, a substation that transforms power supplied via a power transmission system, a transmission line (distribution line) that transmits (distributes) high-voltage power, a pole transformer, and the like.

  P in the figure may represent, for example, a power supply facility in a power transmission system, or may represent a power facility (for example, a substation) that receives power from the power transmission system in a distribution system. In the figure, ND0 to ND4 represent respective power facilities (for example, substations and pole transformers) in the power system. Hereinafter, power facilities represented as ND0 to ND4 will be described as "load nodes". Also, PL1 to PL6 in the figure represent transmission lines in the power system. The power system configuration information 132 indicates, for example, that the load node ND0 is connected to the load node ND1 via the transmission line PL1 and is connected to the load node ND2 via the transmission line PL2, as shown in the drawing. Is represented. The power system configuration information 132 indicates that the load node ND1 and the load node ND2 are connected to each other via the same transmission line PL3. The power system configuration information 132 indicates that the load node ND1 is connected to the load node ND3 via the transmission line PL4, and that the load node ND2 is connected to the load node ND4 via the transmission line PL5. Represents. The power system configuration information 132 indicates that the load node ND3 and the load node ND4 are connected to each other via the same transmission line PL6.

  In the power system illustrated in the figure, the description has been given assuming that the number of load nodes includes five from ND0 to ND4 and the number of transmission lines includes six from PL1 to PL6. May be added, and one or more of the illustrated load nodes and transmission lines may be omitted.

  Hereinafter, the process performed by the control unit 110 will be described with reference to a flowchart. FIG. 3 is a flowchart illustrating an example of a flow of a series of processes performed by the control unit 110 according to the embodiment. The processing of this flowchart may be repeatedly performed at a predetermined cycle, for example.

  First, in the power system indicated by the power system configuration information 132, the stopped facility candidate selection unit 112 stops the operation for updating the equipment from one or more power facilities (transmission lines) existing in the power system. One or more power equipment candidates (hereinafter, referred to as stop equipment candidates) are selected (step S100). For example, the stop facility candidate selection unit 112 selects each of the transmission lines PL1 to PL6 in FIG. 2 described above as a stop facility candidate.

  Next, on the assumption that the stopped facility candidate selected by the stopped facility candidate selecting unit 112 has been stopped, the connection probability calculating unit 114 sets other loads except for the load node ND which is the stopped facility candidate in the power system. The connection probability Pa of the power supply path PS reaching each of the nodes ND is calculated (step S102). The connection probability Pa represents the probability that the load node ND connected to each power supply path PS will not lose power.

For example, when each of the transmission lines PL1 to PL6 is selected as a stop facility candidate by the stop facility candidate selection unit 112, the connection probability calculation unit 114 calculates the connection probability Pa of the following power supply path PS.
(1) The connection probability of the power supply path PS for supplying power to each of the load nodes ND1 to ND4 when the transmission line PL1 is stopped.
(2) The connection probability of the power supply path PS for supplying power to each of the load nodes ND1 to ND4 when the transmission line PL2 is stopped.
(3) The connection probability of the power supply path PS for supplying power to each of the load nodes ND1 to ND4 when the transmission line PL3 is stopped.
(4) The connection probability of the power supply path PS for supplying power to each of the load nodes ND1 to ND4 when the transmission line PL4 is stopped.
(5) The connection probability of the power supply path PS for supplying power to each of the load nodes ND1 to ND4 when the transmission line PL5 is stopped.
(6) The connection probability of the power supply path PS for supplying power to each of the load nodes ND1 to ND4 when the transmission line PL6 is stopped.

  The connection probability calculation unit 114 calculates the connection probability Pa of each power supply path PS using graph theory. For example, the connection probability calculation unit 114 calculates the connection probability Pa of each power supply path PS using a binary decision diagram as a method based on graph theory.

  FIG. 4 is a diagram illustrating an example of a graph structure of the binary decision graph used when calculating the connection probability Pa. The binary decision diagram in the present embodiment is represented by a tree-structured directed graph having no ring structure. In the binary decision graph, each decision node represents each transmission line PLn existing in the power system, and the two-branch edge connecting the decision nodes represents the presence or absence of connection between the transmission lines PLn. The binary decision graph of the illustrated example is a graph referred to in the case of the above (1) (when the transmission line PL1 is stopped).

  In the binary decision graph, for example, when the transmission lines PL that are the decision nodes are connected to each other via the load node ND, the edge between the decision nodes is “1”, and the transmission lines PL are connected. If not, the edge between the decision nodes is “0”. For example, the power supply path PS5 in the figure is a path in which the transmission lines PL2 and PL3 are connected, the transmission lines PL3 and PL4 are connected, the transmission lines PL4 and PL5 are not connected, and the transmission lines PL5 and PL6 are connected. is there. In each of the power supply paths PS, the value of a child node (hereinafter, referred to as an end node) whose parent is the decision node of the deepest hierarchy (the decision node having the largest number of edges to be traced from the start node as the start point) is “ It is determined whether power is supplied to one or more load nodes ND included in the power supply path PS according to whether the power supply path is “0” or “1”. When the value of the terminal node is “0”, it means that power is not supplied to any one or more load nodes ND. When the value of the terminal node is “1”, it means that all the load nodes ND are not supplied. This indicates that power is supplied to the ND.

  For example, the connection probability calculation unit 114 generates a binary decision graph having a graph structure as illustrated in FIG. 4 with reference to the power system configuration information 132. For example, the connection probability calculation unit 114 generates an ordered BDD so that the order of variables appearing when moving from the start node to the lower-level decision node becomes the same (any path).

  The connection probability calculating unit 114 refers to the value of the terminal node of the generated binary decision graph to extract the power supply path PS in which power is supplied to all the load nodes ND when each transmission line PLn is stopped. I do. In the case of the example in FIG. 4, PS1 to PS3, PS5, and PS8 are extracted as the power supply path PS to which power is supplied to all the load nodes ND.

  Then, the connection probability calculation unit 114 calculates the connection probability Pa of the power supply path PS based on the number of times of occurrence of failure of each of the transmission lines PLn constituting the extracted power supply path PS.

FIG. 5 is a diagram illustrating an example of the number of failure occurrences for each transmission line. For example, if the annual number of failure occurrences of the transmission line PL1 is 10 at a certain point in the past, the failure occurrence probability per hour is 0.00114. Connection probability calculation unit 114, the probability of failure occurrence frequency per hour of each transmission line PLn as illustrated in FIG. 5 replaced by (hereinafter, unconsolidated called probability pb _n), unbound from 1 probability pb _n the value obtained by subtracting the calculated as linking probability pa _n of each transmission line PLn.

For example, based on the failure occurrence count for each exemplified transmission lines in Figure 5, coupling probability pa _n calculated for each transmission line PLn is as follows.
Consolidated power lines PL1 probability _{pa 1 = (1-pb 1} ) = 0.99886
Consolidated power lines PL2 probability _{pa 2 = (1-pb 2} ) = 0.99943
Consolidated power lines PL3 probability _{pa 3 = (1-pb 3} ) = 0.99372
- connection of the transmission line PL4 probability _{pa 4 = (1-pb 4} ) = 0.99658
Consolidated the power line PL5 probability _{pa 5 = (1-pb 5} ) = 0.99772
Consolidated power lines PL6 probability _{pa 6 = (1-pb 6} ) = 0.99543

Connection probability calculation unit 114, after calculating the connection probabilities pa _n of each transmission line PLn, for each of the extracted power supply path PS, multiplying the connection probability pa _n of the transmission line PLn included in the power supply path PS. For example, when the connection probability calculation unit 114 extracts the paths of PS1 to PS3, PS5, and PS8 as the power supply path PS to which power is supplied to all the load nodes ND, first, the connection included in the power supply path PS1 multiplying each of the connection probability pa _n from wire PL2 PL6.

For example, connecting probability calculation unit 114, with respect to the power supply path PS1, it calculates the _{pa 2 × pa 3 × pa 4} × pa 5 × pa 6, with respect to the power supply path _{PS2, pa 2 × pa 3 ×} pa 4 × pa ₅ calculates the × (1-pa _6). The coupling probability calculation unit 114, with respect to the power supply path PS3, calculates the _{pa 2 × pa 3 × pa 4} × (1-pa 5) × pa 6, with respect to the power supply path PS5, pa ₂ × pa ₃ × pa ₄ × (1-pa ₅ ) × pa ₆ is calculated. The coupling probability calculation unit 114, with respect to the power supply path PS8, calculates the _{pa 2 × (1-pa 3} ) × pa 4 × pa 5 × pa 6.

The connection probability calculation unit 114, by adding the connection probability pa _n of each transmission line PLn multiplied for each power supply path PS, calculates the connection probability Pa of the entire power supply path PS. In the case of the above numerical example, the connection probability Pa of the entire power supply path PS is (pa ₂ × pa ₃ × pa ₄ × pa ₅ × pa ₆ ) + (pa ₂ × pa ₃ × pa ₄ × pa ₅ × (1 −pa ₆ )) + (pa ₂ × pa ₃ × pa ₄ × (1-pa ₅ ) × pa ₆ ) + (pa ₂ × pa ₃ × pa ₄ × (1-pa ₅ ) × pa ₆ ) + (pa the _{2 × (1-pa 3)} × pa 4 × pa 5 × pa 6) = 0.99933.

  In addition, the connection probability calculation unit 114 calculates the connection probability Pa of the power supply path PS to which power is supplied to each load node ND when the transmission line PL1 is stopped, similarly to the stop equipment candidate selection unit 112. The connection probability Pa of the power supply path PS to which power is supplied to each load node ND when each of the transmission lines PL other than the transmission line PL1 is stopped among the stop equipment candidates selected by (1) is calculated. In the case of the above-described example, since each of the transmission lines PL1 to PL6 is selected as a stop facility candidate by the stop facility candidate selection unit 112, the connection probability calculation unit 114 determines whether one or more of the transmission lines PL2 has been stopped. Of the power supply path PS, the connection probability Pa of one or more power supply paths PS when the transmission line PL3 is stopped, and the one or more electric powers when the transmission line PL4 is stopped. The connection probability Pa of the supply path PS, the connection probability Pa of one or more power supply paths PS when the transmission line PL5 is stopped, and the one or more power supply paths when the transmission line PL6 is stopped. The PS connection probability Pa is calculated using the above-described binary decision graph. As described above, since the connection probability calculation unit 114 calculates the connection probability Pa of the entire power supply path PS using the binary decision graph, it is possible to efficiently search for the power supply path PS while reducing the graph structure. it can.

  FIG. 6 is a diagram illustrating an example of the connection probability Pa of the power supply path PS calculated based on the number of failure occurrences for each transmission line PL illustrated in FIG. The connection probability Pa of the power supply path PS when the transmission line PL1 is stopped is 0.99933 as described above.

  Next, the first system configuration selection unit 116 selects, from the power supply paths PS for which the connection probability Pa has been calculated by the connection probability calculation unit 114, a connection probability Pa equal to or greater than a threshold (hereinafter, referred to as a connection probability threshold Pth). Is selected (step S104).

  For example, when the connection probability Pa is 0.995 and the connection probability Pa of the power supply path PS is the numerical example illustrated in FIG. 6 described above, the first system configuration selection unit 116 determines that the connection probability Pa is The power supply path PS when the transmission line PL1 is stopped (Pa = 0.99933) and the power supply path PS when the transmission line PL2 is stopped (Pa = 0) are the power supply paths PS that are equal to or higher than the probability threshold Pth. .99876), and the power supply path PS (Pa = 0.99995) when the transmission line PL3 is stopped is selected.

  Next, the supply reliability calculating unit 118 calculates, for each of the power supply paths PS selected by the first system configuration selection unit 116, an index value (hereinafter referred to as an index value) indicating the reliability when power is supplied to the power supply path PS. , And supply reliability) (step S106). The supply reliability is represented, for example, as an average number of times (SAIFI: System Average Interruption Frequency Index) that a power facility of a consumer who receives power from each load node ND has a power outage during a predetermined period (for example, one year). For example, SAIFI (for example, the unit is [times / year]) is calculated based on the following equation (1).

The numerator of Equation (1) represents the unconsolidated probability pb _n of the transmission line PLn, the sum of the product of the total number of customers equipment for power failure. That is, the numerator of the equation (1) is a probability of disconnection Pb of a whole power supply path PS including one or more transmission lines PLn, and a demand connected to each load node ND included in the power supply path PS. The product of the total number of the customer facilities out of the house facilities and the power outage is added for all the power supply paths PS. For example, the supply reliability calculation unit 118 calculates the numerator of the SAIFI calculation formula (hereinafter, referred to as the number of power outages Xn) using the above-described binary decision graph.

  FIG. 7 is a diagram illustrating an example of a graph structure of a binary decision graph used when calculating SAIFI. The illustrated example shows a graph structure referred to when the transmission line PL1 is stopped. For example, the supply reliability calculation unit 118 refers to the value of the terminal node of the binary decision graph generated by the connection probability calculation unit 114, and when one of the transmission lines PLn is stopped, one or more loads The power supply path PS to which power is not supplied to the node ND (path in which the value of the terminal node is “0”) is extracted. In the example of FIG. 7, PS4, PS6, PS7, and PS9 to PS14 are extracted as power supply paths PS to which power is not supplied to any one or more load nodes ND. Note that the supply reliability calculation unit 118 may generate the binary decision graph by referring to the power system configuration information 132 instead of referring to the binary decision graph generated by the connection probability calculation unit 114.

  Then, the supply reliability calculation unit 118 calculates the non-connection probability Pb of the entire power supply path PS based on the number of failure occurrences of each of the transmission lines PLn constituting the extracted power supply path PS.

For example, when the number of failure occurrences of each transmission line PLn is the numerical value illustrated in FIG. 5 described above, the supply reliability calculating unit 118 determines, for each of the extracted power supply paths PS, each of the power supply paths PS by multiplying the unconsolidated probability pb _n of the transmission line PLn, calculates an unbound probability Pb of the power supply path PS. For example, when the supply reliability calculation unit 118 extracts the paths of PS4, PS6, PS7, and PS9 to PS14 as the power supply path PS to which power is not supplied to any one or more load nodes ND, multiplying each of unconsolidated probability pb _n of the transmission line PLn included in the supply path PS.

For example, the supply reliability calculation unit 118 calculates the non-connection probability Pb of each power supply path PS by calculating the following.
・ Pb of PS4
= (1-pb ₂ ) × (1-pb ₃ ) × (1-pb ₄ ) × pb ₅ × pb ₆
= (1-0.00057078) × (1-0.00627854) × (1-0.00342466) × 0.0022828311 × 0.00456621
= 0.00001032
・ Pb of PS6
= (1-pb ₂ ) × (1-pb ₃ ) × pb ₄ × (1-pb ₅ ) × pb ₆
= (1-0.00057078) × (1-0.00627854) × 0.00342466 × (1-0.0022828311) × 0.00456621
= 0.00001550
・ Pb of PS7
= (1-pb ₂ ) × (1-pb ₃ ) × pb ₄ × pb ₅
= (1-0.00057078) x (1-0.00627854) x 0.00342466 x 0.002283111
= 0.00000777
・ Pb of PS9
= (1-pb ₂ ) × pb ₃ × (1-pb ₄ ) × (1-pb ₅ ) × pb ₆
= (1-0.00057078) × 0.00627854 × (1-0.00342466) × (1-0.0022828311) × 0.00456621
= 0.00002849
・ Pb of PS10
= (1-pb ₂ ) × pb ₃ × (1-pb ₄ ) × pb ₅
= (1-0.00057078) × 0.00627854 × (1-0.00342466) × 0.0022828311
= 0.00001428
・ Pb of PS11
= (1-pb ₂ ) × pb ₃ × pb ₄ × (1-pb ₅ ) × (1-pb ₆ )
= (1-0.00057078) × 0.00627854 × 0.00342466 × (1-0.00228311) × (1-0.00456621)
= 0.00002134
・ Pb of PS12
_{= (1-pb 2) ×} pb 3 × pb 4 × (1-pb 5) × pb 6
= (1−0.00057078) × 0.00627854 × 0.00342466 × (1−0.00228311) × 0.00456621
= 0.00000010
・ Pb of PS13
= (1-pb ₂ ) × pb ₃ × pb ₄ × pb ₅
= (1-0.00057078) × 0.00627854 × 0.00342466 × 0.0022828311
= 0.00000005
Pb of PS14 = pb ₂ = 0.00057078

  Then, the supply reliability calculation unit 118 multiplies the disconnection probability Pb for each power supply path PS by the total number of customer facilities electrically connected to each load node ND included in the power supply path PS. Then, the numerator in the above equation (1) is calculated.

FIG. 8 is a diagram illustrating an example of the total number of customer facilities electrically connected to each load node ND. In the illustrated example, the total number of customers connected to each load node ND is 35,000. For example, in the power system illustrated in FIG. 2, the number of failure occurrences of the transmission line PLn is the numerical value illustrated in FIG. 5 described above, and the total number of customer facilities electrically connected to each load node ND is illustrated in FIG. 8. If the value is an example, the supply reliability calculation unit 118 calculates the following.
・ Number of power outages of PS4 X4
= (Pb of PS4) x (total number of customer equipment connected to ND4)
= 0.00001032 x 35000
= 0.36114 [times / hour]
・ Number of power outages of PS6 X6
= (Pb of PS6) x (total number of customer equipment connected to ND3)
= 0.00001550 × 35000
= 0.54233 [times / hour]
・ PS7 customer power outage X7
= (Pb of PS7) x (total number of customer equipment connected to ND3, ND4)
= 0.00000777 x (35000 + 35000)
= 0.54357 [times / hour]
・ Number of power outages of PS9 X9
= (Pb of PS9) x (total number of customer equipment connected to ND1, ND3)
= 0.00002849 x (35000 + 35000)
= 1.99426 [times / hour]
・ Number of power outages of PS10 X10
= (Pb of PS10) x (total number of customer facilities connected to ND1, ND3, ND4)
= 0.00001428 x (35000 + 35000 + 35000)
= 1.49912 [times / hour]
・ PS11 customer power outage frequency X11
= (Pb of PS11) x (total number of customer equipment connected to ND3)
= 0.00002134 × 35000
= 0.74699 [times / hour]
・ Number of power outages of PS12 X12
= (Pb of PS12) x (total number of customer equipment connected to ND1, ND3)
= 0.00000010 × (35000 + 35000)
= 0.00685 [times / hour]
・ PS13 customer power outage frequency X13
= (Pb of PS13) x (total number of customer facilities connected to ND1, ND3, ND4)
= 0.00000005 × (35000 + 35000 + 35000)
= 0.00515 [times / hour]
・ Number of power outages of PS14 customers X14
= (Pb of PS14) x (total number of customer equipment connected to ND1 to ND4)
= 0.00057078 × (35000 + 35000 + 35000 + 35000)
= 79.90868 [times / hour]

  Then, the supply reliability calculating unit 118 calculates the SAIFI by substituting the calculated number of power outages Xn of the power supply paths PS4, PS6, PS7, PS9 to PS14 into the above-described equation (1). . For example, Equation (1) in which each customer power failure frequency Xn is substituted is represented as Equation (2) below.

  In addition, the supply reliability calculation unit 118 calculates the power supply path selected by the first system configuration selection unit 116 in the same manner as calculating the non-connection probability Pb of the power supply path PS when the transmission line PL1 is stopped. The non-connection probability Pb of each power supply path PS when each of the transmission lines PL other than the transmission line PL1 among the PSs is stopped is calculated. In the case of the above-described example, since each of the transmission lines PL1, PL2, and PL3 is selected by the first system configuration selection unit 116, the supply reliability calculation unit 118 determines one or more of the transmission lines PL2 when the transmission line PL2 is stopped. The non-connection probability Pb of the power supply path PS and the non-connection probability Pb of one or more power supply paths PS when the transmission line PL3 is stopped are calculated using the above-described binary decision graph. Thus, the SAIFI of each power supply path PS is calculated each time the transmission line PL of the candidate to be stopped is changed. As a result, since the supply reliability calculation unit 118 calculates the non-connection probability Pb of the entire power supply path PS using the binary decision graph, the SAIFI is calculated efficiently.

  The SAIFI (an example of the supply reliability) of each power supply path PS calculated by the supply reliability calculation unit 118 is, for example, a value illustrated in FIG. FIG. 9 is a diagram illustrating an example of the SAIFI of each power supply path PS. In the illustrated example, the first system configuration selection unit 116 uses the SAIFI (= 5.36622) of the power supply path PS when the transmission line PL1 is stopped and the power supply path PS when the transmission line PL2 is stopped. (= 10.38770) and SAIFI (= 0.17212) of the power supply path PS when the transmission line PL3 is stopped.

  In the SAIFI exemplified in the above equation (1), the parameter in the equation is the total number of customer facilities. However, the present invention is not limited to this. For example, the total power consumption of the customer facilities may be replaced. Further, when the power consumption of each customer facility is fixed, the total number of customer facilities and the total power consumption of the customer facility may be regarded as substantially the same value. The customer equipment electrically connected to each load node ND is an example of “load”, and the total number of customer equipment and the total power consumption of the customer equipment are examples of “load scale”.

  Next, the second system configuration selection unit 120 selects, from the power supply path PS for which SAIFI has been calculated as the supply reliability by the supply reliability calculation unit 118, a SAIFI equal to or less than a certain threshold (hereinafter, referred to as SAIFI threshold Sth). Is selected (step S108).

  For example, when the SAIFI threshold Sth is 10 [times / year] and the SAIFI of the power supply path PS is the numerical example illustrated in FIG. 9 described above, the second system configuration selection unit 120 determines that the SAIFI is the SAIFI threshold Sth. The following power supply paths PS are the power supply path PS when the transmission line PL1 is stopped (SAIFI = 5.35662) and the power supply path PS when the transmission line PL3 is stopped (SAIFI = 0.17212). ).

  Next, the system state deriving unit 122 derives an electric state of the power supply path PS selected by the second system configuration selecting unit 120 (Step S110). The electrical state includes, for example, the voltage [pu] at each load node ND, the amount of power [MVA] flowing through each transmission line PL, the transmission loss [MW] of each power supply path PS, and the transmission capacity of each transmission line PL. Is exceeded.

  For example, the system state deriving unit 122 derives the electrical state of the power supply path PS selected by the second system configuration selecting unit 120 using power flow calculation. For example, the system state deriving unit 122 performs a power flow calculation by setting a predetermined load condition for the power supply path PS, and derives various quantities representing an electric state.

  More specifically, the system state deriving unit 122 virtually provides the same power supply path PS when the transmission line PL1 is stopped and the power supply path PS when the transmission line PL3 is stopped. Load current and system impedance are set, and power flow calculation is performed by using a method of iteratively calculating a solution (approximate solution) such as the Newton-Raphson method. For example, the load condition and the system impedance may be set to the following numerical values.

(Load condition A)
Active power P of load node ND1: 47.3 [MW], reactive power Q: 23.0 [MVar]
Active power P of load node ND2: 47.3 [MW], reactive power Q: 23.0 [MVar]
Active power P of load node ND3: 47.3 [MW], reactive power Q: 23.0 [MVar]
Active power P of load node ND4: 47.3 [MW], reactive power Q: 23.0 [MVar]
(Load condition B)
Active power P of load node ND1: 52.5 [MW], reactive power Q: 25.5 [MVar]
Active power P of load node ND2: 52.5 [MW], reactive power Q: 25.5 [MVar]
Active power P of load node ND3: 52.5 [MW], reactive power Q: 25.5 [MVar]
Active power P of load node ND4: 52.5 [MW], reactive power Q: 25.5 [MVar]
(Load condition C)
Active power P of load node ND1: 57.8 [MW], reactive power Q: 28.1 [MVar]
Active power P of load node ND2: 57.8 [MW], reactive power Q: 28.1 [MVar]
Active power P of load node ND3: 57.8 [MW], reactive power Q: 28.1 [MVar]
Active power P of load node ND4: 57.8 [MW], reactive power Q: 28.1 [MVar]
(System impedance)
Transmission line PL2: 0.02 [pu] + j 0.09 [pu]
Transmission line PL3: 0.20 [pu] + j1.00 [pu]
Transmission line PL4: 0.11 [pu] + j 0.55 [pu]
Transmission line PL5: 0.07 [pu] + j0.36 [pu]
Transmission line PL6: 0.05 [pu] + j 0.27 [pu]

  The following figure shows the result of power flow calculation under each load condition. FIG. 10 is a diagram illustrating an example of a power flow calculation result when a load condition A is given when stopping the transmission line PL1. FIG. 11 is a diagram illustrating an example of a power flow calculation result when a load condition B is given when stopping the transmission line PL1. FIG. 12 is a diagram illustrating an example of a power flow calculation result when the load condition C is given when stopping the transmission line PL1. FIG. 13 is a diagram illustrating an example of a power flow calculation result when a load condition A is given when stopping the transmission line PL3. FIG. 14 is a diagram illustrating an example of a power flow calculation result when the load condition B is given when stopping the transmission line PL3. FIG. 15 is a diagram illustrating an example of a power flow calculation result when a load condition C is given when stopping the transmission line PL3. In the power flow calculation illustrated in each of these drawings, each load node ND is treated as a node designated as active power and reactive power, but is not limited thereto. Each load node ND is regarded as a power system indicated by the power system configuration information 132. May be designated as a voltage and active power designation node in accordance with the state of the power equipment actually used as the load node ND.

  For example, in FIG. 10, the active power P supplied from the load node ND0 to the transmission line PL2 is 191.54 [MW], and the reactive power Q is 104.23 [MVar]. The voltage of the load node ND0 is shown as V0 (= 1.000 [pu]). Various powers supplied from the load node ND0 to the transmission line PL2 cause a voltage drop due to the impedance inside the transmission line PL2. When the impedance inside the transmission line PL2 is the above-described numerical example (0.02 [pu] + j0.09 [pu]), the active power P supplied to the load node ND2 by energizing the transmission line PL2 is 190. .59 [MW], and the reactive power Q is 99.95 [MVar]. The power supplied to the load node ND2 is divided and divided into the power transmission line PL3 side, the power transmission line PL5 side, and the customer equipment connected to the own node.

  Active power P supplied to transmission line PL3 from load node ND2 is 47.63 [MW], and reactive power Q is 25.51 [MVar]. Also, the active power P supplied from the load node ND2 to the transmission line PL5 is 95.68 [MW], and the reactive power Q is 51.51 [MVar]. Further, the active power P supplied to the customer equipment from the load node ND2 is 47.25 [MW], and the reactive power Q is 22.95 [MVar]. The active power P supplied to the load node ND1 by energizing the transmission line PL3 causes a voltage drop due to the internal impedance of the transmission line PL3, becomes 47.03 [MW], and the reactive power Q becomes 22.51 [MVar. ]. The power supplied to the load node ND1 is divided and divided into the power transmission line PL4 side and the customer equipment connected to the own node.

  Active power P supplied to transmission line PL4 from load node ND1 is 0.20 [MW], and reactive power Q is 0.43 [MVar]. Further, the active power P supplied to the customer equipment from the load node ND1 is 47.23 [MW], and the reactive power Q is 22.95 [MVar]. The active power P supplied to the load node ND3 by energizing the transmission line PL4 causes a voltage drop due to the internal impedance of the transmission line PL4, becomes 0.20 [MW], and the reactive power Q becomes 0.43 [MVar]. ].

  On the other hand, the active power P supplied to the load node ND4 by energizing the transmission line PL5 has a voltage drop due to the internal impedance of the transmission line PL5, becomes 94.83 [MW], and the reactive power Q is 47.14. [MVar]. The power supplied to the load node ND4 is divided and divided into the power transmission line PL6 side and the customer equipment side connected to the own node.

  The active power P supplied from the load node ND4 to the transmission line PL6 is 47.58 [MW], and the reactive power Q is 24.21 [MVar]. Further, the active power P supplied to the customer equipment from the load node ND4 is 47.24 [MW], and the reactive power Q is 22.95 [MVar]. The active power P supplied to the load node ND3 by energizing the transmission line PL6 causes a voltage drop due to the internal impedance of the transmission line PL6, becomes 47.43 [MW], and the reactive power Q becomes 23.37 [MVar]. ]. The power supplied from the transmission line PL4 and the power supplied from the transmission line PL6 are combined at the load node ND3, and supplied to the customer equipment connected to the load node ND3. The active power P supplied from the load node ND3 to the customer equipment is 47.23 [MW], and the reactive power Q is 22.95 [MVar].

  As described above, the system state deriving unit 122 considers the impedance of the transmission line PL, the impedance of the load node ND, and the impedance of the customer equipment connected to the load node ND, and determines the connection relationship of the transmission line PL. By taking this into account, various electrical state quantities such as the voltage of the load node ND, the amount of power at the time of input / output of the transmission line PL, and the transmission loss are derived.

  FIG. 16 is a diagram illustrating an example of various electric quantities under each load condition when the transmission line PL1 is stopped. FIG. 17 is a diagram illustrating an example of various electrical quantities under each load condition when the transmission line PL3 is stopped. For example, when the transmission line PL1 is stopped and the load condition A is set at the time of the power flow calculation, as illustrated in FIG. 16, the voltage of the load node ND1 is 0.952 [pu], and the voltage of the load node ND2. Is 0.987 [pu], the voltage of the load node ND3 is 0.953 [pu], and the voltage of the load node ND4 is 0.962 [pu]. Further, the power amount (tidal flow) of the transmission line PL2 is 218.1 [MVA], the power amount (tidal flow) of the transmission line PL3 is 54.0 [MVA], and the power amount (tidal flow) of the transmission line PL4 is 0.1 MVA. 5 [MVA], the power amount (tidal flow) of the transmission line PL5 is 108.7 [MVA], and the power amount (tidal flow) of the transmission line PL6 is 53.4 [MVA]. These power amounts (tidal currents) are derived using the active power P and the reactive power Q at the time of input of each transmission line PL. The power transmission loss is 2.6 [MW]. The electrical quantities of each transmission line PL under the load conditions B and C may be the values illustrated in FIGS. 11 and 12, respectively.

  Next, the third system configuration selector 124 selects one or more powers selected by the second system configuration selector 120 based on the electrical state derived for each power supply path PS by the system state derivation unit 122. The power supply path PS established as a system is selected from the supply paths PS (step S112).

  For example, when the electrical quantities derived for each power supply path PS satisfy the following constraint conditions, the third system configuration selection unit 124 selects the power supply path PS as the power supply path PS established as a system. I do. The constraint condition is an example of a “predetermined condition”.

(Constraints)
-Voltage of each load node ND: 1 [pu] ± 0.05 [pu]
-Transmission capacity of transmission line PL1: 250 [MVA]
-Transmission capacity of transmission line PL2: 250 [MVA]
-Transmission capacity of transmission line PL3: 100 [MVA]
-Transmission capacity of transmission line PL4: 200 [MVA]
-Transmission capacity of transmission line PL5: 200 [MVA]
-Transmission capacity of transmission line PL6: 100 [MVA]
・ Transmission loss upper limit: 3 [MW]

  In the case of the above-described constraints, as illustrated in FIG. 16, the electric power supply when stopping the transmission line PL1 among the two electric power supply paths PS selected by the second system configuration selection unit 120, as illustrated in FIG. Since the path PS does not satisfy the constraint, the third system configuration selection unit 124 does not select the power supply path PS for stopping the transmission line PL1 as the power supply path PS established as a system.

  On the other hand, as illustrated in FIG. 17, among the two power supply paths PS selected by the second system configuration selection unit 120, the power supply path PS when the transmission line PL3 is stopped is restricted. In order to satisfy the condition, the third system configuration selection unit 124 selects the power supply path PS for stopping the transmission line PL3 as the power supply path PS established as a system.

  Then, the third system configuration selection unit 124 causes a display device (not shown) or the like to output information on the power supply path PS selected as the power supply path PS established as a system. Thereby, for example, a worker performing maintenance or the like can efficiently plan which power supply path PS should be prioritized for updating the equipment in the power system indicated by the power system configuration information 132. .

  According to the embodiment described above, the second system that selects one or more power supply paths PS whose supply reliability (SAIFI) is equal to or less than the SAIFI threshold value Sth from the plurality of power supply paths PS configuring the power system. The configuration selection unit 120 (an example of a first selection unit), a system state derivation unit 122 that derives the electrical state of the power supply path PS selected by the second system configuration selection unit 120, and a system state derivation unit 122 A power supply path that satisfies the constraint condition from among the one or more power supply paths PS selected by the second system configuration selection unit 120 based on the derived electrical state. By including the third system configuration selection unit 124 (an example of the second selection unit) that selects the PS, the update plan of the power equipment can be made efficiently.

For example, power line PL (stopped for update temporarily) one of the transmission lines PL is stopped in the power system, such as is present 100 equipment case, used as decision node 2 ¹⁰⁰ present a binary decision diagram Will do. In this case, the power supply path PS in the power system has 1.3 × 10 ³⁰ patterns, and if the supply reliability (SAIFI) is calculated or the power flow is calculated for the power supply paths PS of all the patterns. In addition, the calculation cost tends to be enormous. Further, since an approximate solution is obtained by using the Newton-Raphson method or the like at the time of power flow calculation, the larger the pattern of the power supply path PS, the more easily the obtained solution is divergent. As a result, it may be difficult to make an update plan for the power equipment itself.

  On the other hand, in the present embodiment, the supply reliability calculation and the power flow calculation are not performed for all the power supply paths PS including the shutdown facility candidate, but the power supply path PS (connection The supply reliability is calculated only for the power supply path PS whose probability Pa is equal to or more than the connection probability threshold Pth, and further, the power supply path PS (SAIFI is equal to or less than the SAIFI threshold Sth) for which a certain supply reliability is expected Since the power flow calculation is performed only for the power supply path PS, it is possible to increase the efficiency of the calculation processing while reducing the calculation processing required for selecting the power supply path PS as much as possible. As a result, it is possible to efficiently select a stop facility candidate to be subject to facility update, and to efficiently make a plan for updating power equipment.

  According to at least one embodiment described above, one or more power supply paths PS whose supply reliability (SAIFI) is equal to or less than the SAIFI threshold Sth are selected from the plurality of power supply paths PS configuring the power system. A second system configuration selection unit 120 (an example of a first selection unit); a system state derivation unit 122 for deriving an electrical state of the power supply path PS selected by the second system configuration selection unit 120; Based on the electrical state derived by the unit 122, a power supply path PS satisfying the constraint condition is established as a system from among the one or more power supply paths PS selected by the second system configuration selection unit 120. By including the third system configuration selection unit 124 (an example of a second selection unit) that selects the power supply path PS, a power equipment update plan can be made efficiently. .

  Although several embodiments of the present invention have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and equivalents thereof.

Reference Signs List 100: power supply path evaluation device, 110: control unit, 112: stop equipment candidate selection unit, 114: connection probability calculation unit, 116: first system configuration selection unit, 118: supply reliability calculation unit, 120: second system Configuration selecting unit, 122: System status deriving unit, 124: Third system configuration selecting unit, 130: Storage unit, 132: Power system configuration information, PS: Power supply path, ND: Load node, PL: Transmission line

Claims (8)

A first selection unit that selects one or more power supply paths in which an index value based on the number of power outages that occurred during a predetermined period is equal to or less than a threshold, from among the plurality of power supply paths that configure the power system,
A deriving unit that derives an electrical state of the power supply path selected by the first selecting unit;
A second selection unit that selects a power supply path that satisfies a predetermined condition from among the one or more power supply paths selected by the first selection unit based on the electrical state derived by the derivation unit;
A power supply path evaluation device comprising: A probability calculation unit that calculates a connection probability indicating a probability that a load connected to each of the plurality of power supply paths does not lose power, for each of the power supply paths,
A third selection unit that selects one or more power supply routes from the plurality of power supply routes based on the connection probability calculated for each of the power supply routes by the probability calculation unit;
The first selection unit selects a power supply route in which the index value is equal to or less than a threshold from one or more power supply routes selected by the third selection unit.
The power supply path evaluation device according to claim 1. The probability calculation unit uses a power line included in the power system as a node, and uses a graph-structured data expressing the presence / absence of connection of the power line as a two-branch edge to determine a node and an edge representing the power supply path. Calculating the connection probability by tracing,
The power supply path evaluation device according to claim 2. The non-connection probability indicating the probability of occurrence of a power failure for each power supply path selected by the third selection unit, and the scale of a load connected to the power supply path selected by the third selection unit, An index value calculation unit for calculating an index value is further provided,
The first selection unit selects a power supply path in which the index value calculated by the index value calculation unit is equal to or less than a threshold.
The power supply path evaluation device according to claim 2. The index value calculation unit,
A node and an edge representing a power supply path selected by the third selection unit by using data of a graph structure in which a power line included in the power system is set as a node, and whether or not the power line is connected is expressed as a two-branch edge. And calculating the connection probability by tracing
Calculating the index value based on the calculated non-connection probability and the scale of the load connected to the power supply path selected by the third selection unit;
The power supply path evaluation device according to claim 4. The deriving unit derives the electrical state by calculating a power flow of the power supplied to the power supply path selected by the first selecting unit.
The power supply path evaluation device according to claim 1. Computer
From among a plurality of power supply paths constituting the power system, select one or more power supply paths in which an index value based on the number of power outages that occurred during a predetermined period is equal to or less than a threshold,
Deriving the electrical state of the selected power supply path,
Based on the derived electrical state, from among the selected one or more power supply paths, select a power supply path that satisfies a predetermined condition,
Power supply path evaluation method. On the computer,
From among a plurality of power supply paths constituting the power system, one or more power supply paths in which an index value based on the number of power outages that occurred during a predetermined period is equal to or less than a threshold value are selected,
Deriving the electrical state of the selected power supply path,
Based on the derived electrical state, from among the one or more selected power supply paths, a power supply path that satisfies a predetermined condition is selected.
program.

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