JP2009284614A - Device, method, and program for determining system configuration with minimized transmission loss - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device, method, and program for determining a system configuration with minimized transmission loss wherein transmission loss smaller than with a branch exchange method and the configuration of a distribution system with this transmission loss can be determined in a practical calculation time. <P>SOLUTION: A "closed" switch selecting means 12 selects a combination of n (n≥2) unselected "open" switches to be brought to a "closed" state so that mesh systems becomes one in the present system configuration. The state of the switches is changed to the "closed" state. The power flow of the mesh system generated by changing the state to the "closed" state is computed by a load-flow computing means 13. A "open" switch selecting means 14 sequentially selects "closed" switches where the value of current passed through them in the power flow of the mesh system calculated by the load-flow computing means 13 as switches to be brought to an "open" state. The state of the switches is changed to the "open" state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus for determining a transmission loss of a distribution system, and in particular, a transmission loss that is minimum in practical calculation time, and a minimum transmission loss system configuration that can determine the configuration of a distribution system having the transmission loss. The present invention relates to a determination device, a method, and a program.

  In general, as a method of determining the system configuration that minimizes the transmission loss of the distribution system, the distribution system is configured radially and the transmission loss is minimized under the capacity constraints of feeders and switches in the system. Thus, there is known one that determines the open / close state of a switch provided in a power distribution system. Below, an example of the determination method of the distribution system configuration which minimizes the transmission loss of such a distribution system is demonstrated with reference to FIGS.

  FIG. 9A is a configuration diagram of a power distribution system in which five switches 91 to 95 are radially arranged. The switches 91 and 94 are in the “open” state, and the switches 92, 93 and 95 are “ Closed state. Moreover, FIG.9 (b) has shown the load of the said area matched with the section numbers 9a-9g of the distribution system in Fig.9 (a), and the impedance of a section. Here, in the configuration of the power distribution system in FIG. 9, if the section load is uniformly distributed in the section, the transmission loss in each section is expressed by the following equation.

[Equation 1]
ΔP = ∫ (R / L) I (x) ² dx = (R / L) ∫ (Iin− (x / L) Il) ² dx
^{= R (Iin 2 -IinIl + Il} 3/3)
ΔP: Section transmission loss Iin: Section input current [A]
Il: Section load [A]
L: Section length [m]
R: Section impedance [Ω]
x: Distance from input end [m]
I (x): passing current [A] at a distance x [m] from the input end

  That is, the transmission loss in each section of the distribution system configured radially as shown in FIG. 9 is calculated as shown in FIG. 10 by substituting the load and impedance shown in FIG. 9B for [Equation 1]. Can do. In order to determine the system configuration that minimizes the power transmission loss in the configuration of the distribution system of FIG. 9, power is transmitted to the switching states of all the switches 91 to 95 so that the distribution system maintains a radiating state. The loss is calculated, and the switching states of the switches 91 to 95 are determined so that the total loss is minimized.

  Here, FIG. 11 is a diagram showing all combinations of the switching states of the switches in such a radially configured distribution system, and FIG. 12 is a transmission loss corresponding to the configuration of each distribution system in FIG. It is the result of having calculated. According to FIG. 12, the minimum value of power transmission loss is 56.267 W, and it can be seen that FIG. 11 (f) shows the configuration of the distribution system having the minimum power transmission loss.

  However, in an actual large-scale distribution system, applying this method of calculating transmission loss for all switch combinations of switches will result in an enormous number of combinations and transmission loss in practical calculation time. It was impossible to determine the distribution system configuration that minimizes the power distribution system. Therefore, a determination device that obtains a system configuration that minimizes power transmission loss by various methods has been proposed.

In addition to the above method, for example, a branch exchange method has been proposed as a system configuration determination method for minimizing transmission loss of a distribution system (see Non-Patent Document 1). In this branch exchange method, in a radial distribution system, a switch in an “open” state is changed to a “closed” state to form one loop, and the power flow current of the created loop is calculated to calculate the switch current. Of these, the system configuration in which the switch with the smallest passing current is set to the “open” state is determined and this process is repeated for all the switches in the “open” state. The system configuration is extracted.
S. Civanlar et. al, “Distribution Feeder Reconfiguration for Loss Reduction”, IEEE Trans. Power Delivery, Vol. 3, No. 3, 1988

  By the way, an example of a method for determining the configuration of a distribution system that minimizes power transmission loss by the branch exchange method as described above will be described below with reference to FIGS.

  First, when the branch exchange method is applied to the distribution system of FIG. 9, a loop is created by closing the switch 91 in the “open” state, and each switch 91 is calculated by calculating a current flow in the loop. The current passing through ˜93, 95 is calculated. The passing currents of the switches 91 to 93 and 95 are the currents that flow through the switches 91 by closing the switches 91 with respect to the passing currents of the system configuration of FIG. 9 in which the switches 91 are in the “open” state. Is calculated by adding.

  Further, the passing current of the switch 91 can be calculated using the Thevenin's law from the potential difference between both ends of the switch 91 in the state of FIG. The potential difference between both ends of the switch 91 is obtained by calculating the voltage drop Vd [V] in each section by the following equation.

[Equation 2]
Vd = ∫ (R / L) I (x) dx = (R / L) ∫ (Iin− (x / L) Il) dx = R (Iin−Il / 2)

  A potential difference between both ends of the switch 91 is obtained based on the calculated voltage drop Vd of each switch section, and a current generated by closing the switch 91 is calculated by the following formula using the Thevenin's law.

[Equation 3]
ΔI = ΔV / Rloop
ΔI: current flowing in the circuit by closing the switch [A]
ΔV: Potential difference across the switch [V]
Rloop: Impedance [Ω] of the loop that can be generated when the switch is closed

Here, FIG. 13 shows the passing current of each switch 91 to 95 and the voltage drop in each section of the distribution system of FIG. That is, the potential difference of the switch 91 is
ΔV = −0.42-(− 0.05−0.125−0.225−0.35) = 0.33
The current change caused by closing the switch 91 is
ΔI = 0.33 / (0.028 + 0.01 + 0.01 + 0.01 + 0.01 + 0.01) = 4.853 [A]
It becomes. Therefore, the passing currents of the switches 91 to 93 and 95 after closing the switch 91 are as shown in FIG.

  In the branch exchange method, the power transmission loss of the newly constructed radial distribution system is calculated by opening the switch that minimizes the passing current in the loop. That is, according to FIG. 14, the switch with the minimum passing current is the switch 91. Therefore, the system configuration is the same in the operation of setting the switch 91 in the “open” state, and the transmission loss does not change.

  Further, when a similar process is performed on the switch 94, that is, an operation for bringing the switch into the “open” state, the passing current of the loop system is calculated as shown in FIG. Here, according to FIG. 15, the switch with the smallest passing current is also the switch 94, so that the configuration of the power distribution system is the same and the transmission loss does not change.

  From the above, when the branch exchange method is applied to the distribution system of FIG. 9, only one switch in the “open” state can be put in the “closed” state at a time, so that the transmission loss is minimized. In order to determine the configuration of the distribution system, many iterative calculations are required, and since the search neighborhood is narrow, the calculation result tends to fall into a local optimal solution. For this reason, a system configuration in which the power transmission loss is a true minimum value as shown in FIG. 11F cannot be acquired.

  The present invention has been proposed in order to solve the above-described problems, and its purpose is a practical calculation time and a power transmission loss smaller than the branch exchange method, and a power distribution having the power transmission loss. An object of the present invention is to provide an apparatus, a method, and a program for determining a minimum transmission loss system configuration capable of determining a system configuration.

  In order to achieve the above-described object, the present invention provides a minimum transmission loss system configuration determination device that determines a minimum transmission loss system configuration that minimizes a transmission loss among system configurations in which the switching state of the switch is changed. A closed switch selecting means for selecting two or more open switches from a plurality of switches to be closed so as to create one mesh system in the system configuration; Open switch selection means for selecting the number of switches in the closed state as many as the number of switches selected by the switch selection means to be in an open state so as to obtain a radial system configuration, and the closed switch The transmission loss of each system configuration in which the switch in the open state selected by the selection means is changed to the closed state, and the switch in the closed state selected by the open switch selection means is changed to the open state. Transmission loss calculation means to calculate and previous A reduction determination unit that determines whether the transmission loss of the predetermined system configuration calculated by the transmission loss calculation unit is lower than the transmission loss of another system configuration calculated earlier, and the reduction determination unit that determines that the transmission loss is reduced by the reduction determination unit Update means for updating a system configuration having a reduced transmission loss as a minimum transmission loss system candidate, and a determination means for determining a minimum transmission loss system configuration from the minimum transmission loss system candidate. The reduction determination means determines that none of the transmission losses of each system configuration calculated by the transmission loss calculation means is lower than the transmission loss of the minimum transmission loss system candidate in the latest updated state. In this case, the minimum transmission loss system candidate is determined as the minimum transmission loss system configuration.

  In addition, the open switch selection unit sequentially selects a switch in a closed state with a minimum passing current among the switches in the mesh system.

  The closed switch selection means can select not only a plurality of open switches to be closed, but also a single open switch including a single switch. Also, it is an aspect of the present invention that the number of switches to be selected is variable by providing the number of switches for switching to change the number of switches to be selected by the closed switch selection means.

  In addition, an initial system generation unit that generates a plurality of initial systems by randomly changing the switching state of the switch is provided, and the closed switch selection unit is included in each initial system generated by the initial system generation unit. The point which selects the switch in an open state so that one mesh system | strain may be created is also included as 1 aspect of this invention.

  According to the present invention as described above, a plurality of "open" state switches are changed to the "closed" state at the same time, and the same number of switches are set to the "open" state, whereby the branch exchange method described above Compared to the above, it is possible to search in a wide range, and therefore, it is possible to provide a determination apparatus, a method, and a program for determining a minimum transmission loss system configuration capable of determining a smaller transmission loss and a system configuration having the transmission loss. Can do.

[1. First Embodiment]
[Constitution]
Next, the configuration of the determination device for the minimum power transmission loss system configuration that minimizes the power transmission loss of the distribution system according to the first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram illustrating the configuration of the minimum power loss system configuration determining apparatus according to the first embodiment.

  As shown in FIG. 1, the minimum power transmission loss system configuration determining apparatus includes a calculation unit 1, an input unit 2, a storage unit 3, a display unit 4, and an I / F unit 5. The I / F unit 5 is connected to the power distribution system 7 via the power distribution system monitoring control device 6.

  Specifically, the computing means 1 is realized by a main memory of a computer, a program stored therein, a CPU controlled by the program, and the like, and has processing means 10 to 17 as will be described later. The input means 2 is an input device such as a mouse or a keyboard for inputting a signal corresponding to a user operation to the computer.

  The storage unit 3 stores in advance various system information data necessary for processing in the calculation unit 1 and stores the calculation result by the calculation unit 1 and is realized by various memories of the computer, an auxiliary storage device, and the like. . The distribution system information data is, for example, information such as the connection state of the distribution line, the impedance, the switching state of the switch, and the load.

  The display unit 4 is a display device such as a display that displays data input through the input unit 2, data stored in the storage unit 3, and calculation results processed by the calculation unit 1 to the user. The I / F unit 5 is a part that transmits and receives system information data and control data of the distribution system 7 via the distribution system monitoring and control device 6, and the received system information data is stored in the storage unit 3. The power distribution system monitoring and control device 6 is a device that performs monitoring control of the power distribution system 7 and holds various data related to the planning, operation, and control of the power distribution system 7.

  The computing means 1 includes a data reading means 10, a power transmission loss calculating means 11, a “closed” switch selecting means 12, a power flow calculating means 13, an “open” switch selecting means 14, a power transmission loss reduction determining means 15, an initial stage. System comparison means 16 and loss minimization configuration update means 17 are provided.

  The data reading means 10 is means for reading system information data from the storage means 3, that is, data relating to the configuration of the distribution system, the open / close state of the switch provided in the system, and the load and impedance.

  The power transmission loss calculation means 11 calculates the power transmission loss in the system configuration changed by opening and closing a switch provided in the distribution system 7. The “closed” switch selection means 12 selects n (n ≧ 2) switches that are changed from the plurality of switches in the “open” state to the “closed” state among the switches constituting the distribution system 7. select.

  The tidal current calculation means 13 is a means for calculating the power flow of the mesh system created by changing the n switches selected by the “closed” switch selection means 12 to the “closed” state.

  The “open” switch selecting means 14 constitutes the mesh system in the mesh system created by changing the n switches selected by the “closed” switch selecting means 12 to the “closed” state. Of the switches in the “closed” state, n switches to be changed to the “open” state are selected. As an example, the “open” switch selecting means 14 is a switch that should be set to the “open” state for the switch having the smallest value of the current passing through the power flow of the mesh system calculated by the power flow calculating means 13. Select sequentially.

  The power transmission loss reduction determining means 15 is a means for determining whether the power transmission loss is reduced with respect to a new system configuration in which the switching state of the switch is changed compared to the previous system configuration. For example, it is determined whether the current power transmission loss calculated by the power transmission loss calculating means 11 is reduced as compared with the solution candidates that are sequentially updated.

  The power transmission loss reduction determining unit 15 stores the current power transmission loss as a new solution candidate through the storage unit 3 when determining that the current power transmission loss is lower than the solution candidate. The initial system comparison unit 16 is a unit that determines whether the transmission loss of the solution candidate is lower than the transmission loss of the initial system.

  The loss minimizing configuration updating unit 17, when the initial system comparison unit 16 determines that the transmission loss of the solution candidate is lower than the transmission loss of the initial system, the transmission loss of the solution candidate and the transmission loss Is updated as the minimum power transmission loss and the system configuration, and is stored in the storage unit 3.

[Action]
Next, the procedure for determining the minimum transmission loss and the system configuration having the transmission loss in the minimum transmission loss system configuration determination apparatus having the configuration of FIG. 1 will be described below with reference to the flowchart of FIG.

  According to FIG. 2, first, in STEP 201, the data reading means 10 obtains system information data such as data relating to the configuration of the power distribution system, the switching state of the switches provided in the system, and the load and impedance from the storage means 3. Read and prepare data to be used in the subsequent processing. Here, the system configuration used in the initial stage is the initial system configuration, and this is set as a solution candidate. Moreover, since this initial system configuration is directed to a radial distribution system, the distribution system that is the target of minimizing transmission loss also has a radial configuration.

  Here, in STEP 201, as an initialization process, the transmission loss calculation means 11 calculates the transmission loss of the solution candidate that is the initial system, and stores it in the storage means 3 as the initial transmission loss. The initial system configuration having the initial transmission loss stored in the storage unit 3 is adopted as the system configuration in the current distribution system, and serves as a reference for performing a system configuration update process to be described later.

  In STEP 202, the “closed” switch selection means 12 selects a combination of n (n ≧ 2) “open” state switches that are not selected and should be in the “closed” state in the current system configuration. To do. Here, the set of n switches selected by the “closed” switch selection means 12 is selected so that one mesh system is created by closing the switch.

  In addition, when the scale of the target distribution system for minimizing transmission loss is large, the number of combinations of n “open” switches in the distribution system increases, which may increase the calculation time. Is done. In such a case, the “closed” switch selecting unit 12 includes a limiting unit that limits the number of n switches to be selected. By this limiting unit, for example, the potential difference between both ends of the switch is large. The number of sets of switches can be limited in the order that includes the switches.

  Here, when the “closed” switch selecting means 12 selects n “open” switches, the “open” switch is changed to the “closed” state on the model. In STEP 203, this “closed” switch is selected. The power flow of the mesh system created when the state is changed is calculated by the power flow calculation means 13.

  In STEP 204, the “open” switch selecting means 14 selects one switch to be set to “open” among the switches in the “closed” state of the created mesh system. Specifically, in the power flow of the mesh system calculated by the power flow calculation means 13 in STEP 203, the switch in the “closed” state that minimizes the current value passing through is selected as the switch that should be in the “open” state. . In particular, a switch in the “closed” state that minimizes the passing current is selected as a switch that should be in the “open” state based on the capacity constraint of the transmission line.

  When the “open” switch selecting unit 14 selects n “closed” switches, the “closed” switch is changed to an “open” state on the model. In STEP 205, this “open” switch is selected. The power flow of the new mesh system created when the state is changed is calculated again by the power flow calculation means 13.

  Here, in STEP 205, based on the newly calculated power flow, the “open” switch selection means 14 selects the switch in the “closed” state in which the passing current value is minimum, and the selected switch The process of changing the device to the “open” state and calculating the power flow of the newly created mesh system through the flow calculation means 13 is repeated n times.

  In other words, among the created “closed” state switches of the mesh system, the “open” switch selecting means 14 selects n “closed” state switches one by one, and calculates the power flow. The means 13 changes the selected switch to the “open” state, and calculates the power flow n times for the remaining mesh system.

  In STEP 206, the power transmission loss calculation means 11 calculates the power transmission loss of the radial system reconfigured by the processing of STEPs 204 and 205 repeated n times. In STEP 207, the transmission loss reduction determination means 15 determines whether or not the current transmission loss of the radial system calculated by the transmission loss calculation means 11 is lower than the transmission loss of the solution candidate.

  If the current transmission loss is lower than the transmission loss of the solution candidate (YES in STEP 207), in STEP 208, the current system configuration and transmission loss are stored as new solution candidates and the transmission loss through the storage means. On the other hand, if the current transmission loss is not reduced below the solution loss of the candidate solution (NO in STEP 207), the transmission loss and the system configuration having the transmission loss are not stored as solution candidates, and are processed in STEP 209. Transition.

  In STEP 209, the “closed” switch selecting means 12 has n “s” in different arrangements from the arrangement of the “open” state switches configured by the processing of STEPs 204 and 205 repeated n times. It is determined whether there is a set of switches in the “open” state. That is, it is determined whether there are n other “open” switch groups that are not selected.

  If there are other n “open” switch sets (YES in STEP 209), the process returns to STEP 202, and a new n “open” switch set is “closed” open / close. It is selected by the device selection means 12, and the subsequent processing is repeated. On the other hand, when there is no other set of n “open” switches (NO in STEP 209), the initial system comparison means 16 causes the transmission loss of the solution candidate in STEP 208 to be greater than the transmission loss of the initial system. It is determined whether it is reduced (STEP 210).

  When it is determined that it is smaller than the initial transmission loss (YES in STEP 210), the loss minimization configuration updating unit 17 updates the storage candidate 3 through the storage unit 3 with the solution candidate and the transmission loss as the initial system configuration and the initial transmission loss. (STEP 211). When updated by the loss minimization configuration updating means 17, the processing from STEP 202 onward is repeated based on the updated initial system configuration and initial transmission loss.

  On the other hand, when it is determined that the transmission loss of the solution candidate is smaller than the initial transmission loss (NO in STEP 210), the current initial system configuration and the initial transmission loss are set as the minimum transmission loss system configuration and the minimum transmission loss. Output (STEP 212), and the process ends ("corresponds to the determination means" of the present invention).

[Example]
Next, with reference to FIGS. 9 and 11 used in the prior art, a specific example of the first embodiment will be described below based on FIGS. As shown in FIG. 2, since only two “open” state switches exist in FIG. 9A, n = 2.

  In STEP 201, the data reading means 10 reads the power distribution system configuration (initial system configuration) as shown in FIG. 9A and the system information data as shown in FIG. 9B from the storage means 3 as initialization processing. Then, the transmission loss calculation means 11 calculates the transmission loss of the solution candidate which is the initial system configuration of FIG. 9, and obtains 57.567 [W] as shown in FIG. This power transmission loss is stored in the storage means 3 as the initial power transmission loss.

  In STEP 202, the “closed” switch selection means 12 selects a combination of two “open” state switches that should be in the “closed” state in the system configuration of FIG. Two “open” switches are changed to the “closed” state. In STEP 203, as shown in FIG. 3, the power flow calculation means 13 calculates the power flow of the mesh system created when the state is changed to the “closed” state.

  In STEP 204, the “open” switch selecting means 14 selects the switch 92 that minimizes the passing current, and the system configuration as shown in FIG. Is obtained. In STEP 205, the power flow calculation means 13 calculates the power flow of the new mesh system of FIG. 4 created when the state is changed to the “open” state.

  By repeating the processing of STEPs 204 and 205 a total of two times (since n = 2), the switch 95 having the smallest passing current value is changed to the “open” state in the system configuration of FIG. A mesh system as shown in FIG. 11 (f) is created, and the power flow of the created system configuration is calculated by the power flow calculation means 13.

  In STEP 206, the power transmission loss calculation means 11 calculates the power transmission loss of the newly configured system configuration, and as shown in FIG. 12, the power transmission loss 56.267 corresponding to the system configuration of FIG. [A] is obtained.

  In STEP 207, the power transmission loss reduction determining means 15 determines whether or not the power transmission loss corresponding to the system configuration of FIG. 11 (f) calculated by the power transmission loss calculating means 11 is lower than the solution loss of the solution candidate. . Specifically, the power transmission loss reduction determination unit 15 includes the power transmission loss 56.267 [W] of the system configuration and the initial power transmission loss 57.567 [W] calculated by the power transmission loss calculation unit 11 in the initialization process of STEP 201. By comparing (see FIG. 10), it is determined that the current transmission loss is lower than the solution loss of the solution candidate. As shown in FIG. 12, there is no system configuration having a transmission loss smaller than this transmission loss 56.267 [W], so even when another “open” switch set is selected, There is no system configuration below the transmission loss of the system configuration in FIG.

  Subsequently, since the current transmission loss is smaller than the transmission loss of the solution candidate (YES in STEP 207), in STEP 208, this system configuration and transmission loss 56.267 [W] are set as a new solution candidate and its transmission loss. Store through storage means.

  In STEP 209, the “closed” switch selection means 12 determines whether there are two “open” switch groups having different arrangements with respect to the system configuration of FIG. The If there are other two “open” switch groups (YES in STEP 209), the process returns to STEP 202 and two new “open” switch groups are “closed”. “Selected by the switch selection means 12, and the subsequent processing is repeated.

  On the other hand, when there is no other set of two “open” switches (NO in STEP 209), the initial system comparison means 16 causes the transmission loss of the solution candidate in STEP 208 to be greater than the transmission loss of the initial system. It is determined whether it is reduced (STEP 210).

  When it is determined that it is smaller than the initial transmission loss (YES in STEP 210), the loss minimization configuration updating unit 17 updates the storage candidate 3 through the storage unit 3 with the solution candidate and the transmission loss as the initial system configuration and the initial transmission loss. (STEP 211). When updated by the loss minimization configuration updating means 17, the processing from STEP 202 onward is repeated based on the updated initial system configuration and initial transmission loss.

  On the other hand, when it is determined that the transmission loss of the solution candidate is smaller than the initial transmission loss (NO in STEP 210), the current initial system configuration and the initial transmission loss are set as the minimum transmission loss system configuration and the minimum transmission loss. Output (STEP 212), the process is terminated. That is, the system configuration in FIG. 11F is output as the minimum power transmission system configuration that minimizes the power transmission loss.

[effect]
According to the present embodiment as described above, it is possible to widen the search range by changing a plurality of “open” state switches to the “closed” state at a time and setting the same number of switches to the “open” state. It is possible to provide a minimum transmission loss system configuration determining apparatus, method, and program capable of determining a smaller transmission loss and a system configuration having the transmission loss and reducing the time required to determine the system configuration. .

  The “open” switch selecting means 14 in the above embodiment selects one switch in the “closed” state to be “open” one by one, but is not limited to this mode. The present invention also includes an embodiment in which n switches in the “closed” state are selected and changed to the “open” state.

[2. Second Embodiment]
[Constitution]
Next, the configuration of the minimum transmission loss system configuration determining apparatus that minimizes the transmission loss of the distribution system according to the second embodiment of the present invention will be described below with reference to FIG. FIG. 5 is a block diagram showing a configuration of a determination apparatus for a minimum transmission loss system configuration according to the second embodiment for minimizing transmission loss. Here, in FIG. 5, the same components as those in FIG.

  In the second embodiment, in addition to the configuration of FIG. 1 in the first embodiment, a switch number changing means 18 is provided. This switch number changing means 18 is selected at a time by the “closed” switch selecting means 12. The number of switches to be changed is changed. In particular, the switch number changing means 18 determines whether the number of selected switches is equal to n, which is a predetermined number of preset switches, and the number of selected switches is less than n. In this case, the number of switches to be selected at a time is increased by one up to n.

[Action]
Next, the procedure for determining the minimum transmission loss and the system configuration having the transmission loss in the minimum transmission loss system configuration determining apparatus having the configuration of FIG. 5 will be described below with reference to the flowchart of FIG. FIG. 6 is a diagram illustrating a determination flow of a system configuration having the minimum power transmission loss according to the second embodiment.

  First, in STEP 601, as in the first embodiment, in STEP 201, the data reading means 10 receives data relating to the configuration of the power distribution system from the storage means 3, the switching state of the switch provided in the system, and the load and impedance. The system information data such as is read out, and data to be used in the subsequent processing is prepared. Here, the system configuration used in the initial stage is the initial system configuration, and this is set as a solution candidate.

  In addition, as an initialization process, the transmission loss calculation unit 11 calculates the transmission loss of the solution candidate that is the initial system, and stores it in the storage unit 3 as the initial transmission loss. The initial system configuration having the initial transmission loss stored in the storage unit 3 is adopted as the system configuration in the current distribution system, and serves as a reference for performing a system configuration update process to be described later.

  Here, in STEP 602, when selecting n (n ≧ 1) “open” state switches that are not selected, the “closed” switch selection unit 12 should be in the “closed” state. N = 1. Similarly to the first embodiment, the “closed” switch selection unit 12 selects one (open at first) “open” state switch that should not be in the “closed” state. Select.

  As in the first embodiment, when the scale of the distribution system targeted for minimizing transmission loss is large, a set of n “open” switches in the current system configuration increases. Therefore, there is a concern about an increase in calculation time. In such a case, the “closed” switch selecting unit 12 includes a limiting unit that limits the number of n switches to be selected. By this limiting unit, for example, the potential difference between both ends of the switch is large. The number of sets can be limited in the order including switches.

  When this “closed” switch selecting means 12 selects one “open” switch (initially n = 1), the “open” switch is changed to the “closed” state on the model. In STEP 603, the power flow of the mesh system created when the state is changed to the “closed” state is calculated by the power flow calculation means 13.

  In STEP 604, among the created “closed” state switches of the mesh system, the “open” switch selection unit 14 selects one switch to be set in the “open” state. Specifically, in the mesh system power flow calculated by the power flow calculation means 13 in STEP 603, the switch in the “closed” state that minimizes the value of the current passing through is selected as the switch to be set in the “open” state. . In particular, a switch in the “closed” state that minimizes the passing current is selected as a switch that should be in the “open” state based on the capacity constraint of the transmission line.

  When the “open” switch selecting means 14 selects one “closed” switch, the “closed” switch is changed to the “open” state on the model. In STEP 605, this “open” switch is selected. The power flow of the new mesh system created when the state is changed is calculated by the power flow calculation means 13. In STEP 606, the power transmission loss calculation means 11 calculates the power transmission loss of the reconfigured radial system. In STEP 607, the power transmission loss reduction determination means 15 calculates the current power transmission loss of the radial system calculated by the power transmission loss calculation means 11. However, it is determined whether or not it is lower than the transmission loss of the solution candidate.

  If the current transmission loss is lower than the transmission loss of the solution candidate (YES in STEP 607), in STEP 608, the current system configuration and transmission loss are stored as new solution candidates and the transmission loss through the storage unit. On the other hand, if the current transmission loss is not reduced below the candidate transmission loss (NO in STEP 607), the transmission loss and the system configuration having the transmission loss are not stored as solution candidates and are processed in STEP 609. Transition.

  In STEP 609, there is one “open” switch group in which the “closed” switch selection means 12 is arranged differently from the arrangement of the “open” switch in the configured system configuration. Determine whether. That is, it is determined whether or not there is one other “open” switch group that is not selected. In STEP 609, when n ≧ 2, the “closed” switch selecting means 12 opens and closes n “open” states of the system configuration configured by repeating the processes of STEPs 604 and 605 n times. It is determined whether there is a set of n “open” switches in a different arrangement from the arrangement of the appliances.

  If there is another such set of “open” switches (YES in STEP 609), the process returns to STEP 602, and one new “open” switch set is “closed” open / close. It is selected by the device selection means 12, and the subsequent processing is repeated. On the other hand, when there is no other switch set in the “open” state (NO in STEP 609), the initial system comparison means 16 causes the transmission loss of the solution candidate in STEP 608 to be greater than the transmission loss of the initial system. It is determined whether it is reduced (STEP 610).

  If it is determined that it is smaller than the initial transmission loss (YES in STEP 610), the loss minimizing configuration updating unit 17 updates the solution candidate and the transmission loss as the initial system configuration and the initial transmission loss through the storage unit 3. (STEP 611). When updated by the loss minimization configuration updating means 17, the processing after STEP 602 is repeated based on the updated initial system configuration and initial transmission loss.

  On the other hand, when it is not determined that the transmission loss of the solution candidate is smaller than the initial transmission loss (NO in STEP 610), the switch number changing means 18 is changed by the “closed” switch selecting means 12 in STEP 612. It is determined whether or not the number of selected switches is equal to a preset n (a predetermined number of preset switches).

  If it is less than the preset number n, for example, if n ≧ 2 (NO in STEP 612), the switch number changing means 18 increases the number from n = 1 by 1, and then returns to STEP 602 again. Return and repeat the process. That is, the processing of STEPs 602 to 611 is repeated n times in order from 1 to the number of switches in the “open” state selected by the preset “closed” switch selection means 12.

  In the processing of STEPs 604 and 605 in the case of n ≧ 2, as in the first embodiment, the “open” switch selection unit 14 minimizes the passing current value based on the calculated power flow. By selecting the switch in the “closed” state, the process is changed to the “open” state, and the power flow calculation means 13 calculates the power flow of the newly created mesh system n times.

  In STEP612, when the switch number changing unit 18 determines that the number of switches selected by the “closed” switch selecting unit 12 is equal to the preset number n (YES in STEP612), The initial system configuration and the initial transmission loss are output as the minimum transmission loss system configuration and the minimum transmission loss (STEP 613), and the process is terminated.

[effect]
According to the present embodiment as described above, the number of switches that are changed from the “open” state to the “closed” state at a time can be increased sequentially from 1, so that the search range is expanded, and further, calculation In the initial stage where the number of switches to be changed is small, the transmission loss that can be minimized can be calculated at high speed, while the number of switches to be changed has increased. It is possible to gradually improve the degree of minimization of transmission loss.

  In the present invention, the switch number changing means 18 in the above embodiment determines whether or not the number of switches selected by the “closed” switch selection means 12 is equal to a preset number n. The number of switches is increased when the set number is less than n, but is not limited to this.

  Specifically, in the present invention, when the transmission loss of the system configuration calculated by the transmission loss calculation unit 11 is determined not to be lower than the transmission loss of the solution candidate by the transmission loss reduction determination unit 15, Embodiment in which the switch number changing means 18 increases the number of switches to be selected by the “closed” switch selecting means 12 one by one when the system comparison means 16 determines that the initial transmission loss has not been reduced. Is included. That is, when the power transmission loss calculated by the power transmission loss calculation unit 11 is not reduced in the predetermined number of switches selected by the “closed” switch selection unit 12, the “closed” switch selection unit 12. By increasing the number of switches selected by the above, it becomes possible to search for the minimum power transmission loss.

[3. Third Embodiment]
[Constitution]
Next, the configuration of the minimum transmission loss system configuration determining apparatus according to the third embodiment of the present invention will be described below with reference to FIG. FIG. 7 is a block diagram showing a determination apparatus for a minimum transmission loss system configuration according to the third embodiment for minimizing transmission loss. Here, in FIG. 7, the same components as those in FIG.

  In the third embodiment, in addition to the configuration of FIG. 1 in the first embodiment, an initial system generation unit 19, an initial system selection unit 20, and a minimized configuration selection unit 21 are provided.

  The initial system generation means 19 is a means for generating a plurality of initial systems having different system configurations in a certain initial system. The initial system selection means 20 is a means for selecting an initial system that has not been selected from a plurality of initial systems, and the minimized configuration selection means 21 has a minimum transmission loss calculated based on all initial system configurations. This is a means for selecting the system configuration having the smallest power transmission loss among the system configurations.

[Action]
Next, the procedure for determining the minimum transmission loss and the system configuration having the transmission loss in the minimum transmission loss system configuration determining apparatus having the configuration of FIG. 7 will be described below with reference to the flowchart of FIG. FIG. 8 is a diagram illustrating a determination flow of a system configuration having a minimum power transmission loss according to the third embodiment. Here, the description of the same processing as the flowchart of FIG. 2 is omitted.

  First, in STEP 801, as in the first embodiment, the data reading unit 10 is configured to store a system such as a data distribution system configuration from the storage unit 3, a switching state of a switch provided in the system, and data related to a load and an impedance. Information data is read out and data to be used in the subsequent processing is prepared. Here, the system configuration used in the initial stage is the initial system configuration, and this is set as a solution candidate.

As an initialization process, the transmission loss calculation means 11 calculates the transmission loss of the solution candidate that is the initial system, and stores it in the storage means 3 as the initial transmission loss. The initial system configuration having the initial transmission loss stored in the storage unit 3 is adopted as the system configuration in the current distribution system, and serves as a reference for performing a system configuration update process to be described later.

  In STEP 802, the initial system generation unit 19 creates a plurality of different system configurations for the read initial system, and calculates the initial transmission loss for each system configuration through the transmission loss calculation unit 11. Note that the plurality of initial system configurations created by the initial system generation means 19 are, for example, that the randomly selected “open” state switch is closed with respect to the initial system, and the random mesh is configured in the configured mesh system. It is created by the method of opening the selected switch.

  In STEP 803, the initial system selection unit 20 selects a new system configuration that has not been selected from among the plurality of initial system configurations created by the initial system generation unit 19. Thereafter, the minimum transmission loss and the minimum transmission loss system configuration calculated based on the selected initial system configuration are performed by executing the same processing as the processing of STEPs 202 to 211 in FIG. 2 in the first embodiment. Can be derived (STEP 804-813).

  In STEP 814, the initial system selection means 20 determines whether there is another initial system configuration that has not been subjected to the power transmission loss minimizing process. If there is present (YES in STEP 814), the process proceeds to STEP 803. A new initial system configuration is selected.

  When the initial system selection unit 20 determines that no other initial system configuration exists (NO in STEP 814), in STEP 815, the minimized configuration selection unit 21 is calculated based on all initial system configurations. Among the transmission losses, the system configuration having the minimum transmission loss is selected, the selected system configuration and the transmission loss are output as the minimum transmission loss system configuration and the minimum transmission loss, and the process is terminated.

[effect]
According to the present embodiment as described above, since a plurality of initial system configurations can be created in advance, it is possible to calculate the minimum transmission loss for each initial system configuration, and the transmission loss calculation process Can be prevented from falling into a local optimal solution. Therefore, a wide range can be set as a search target, and a system configuration with a smaller power transmission loss can be determined.

  The present invention relates to the initial system generation means 19 for generating a plurality of initial systems having different system configurations and an initial system configuration that is not selected from the plurality of initial system configurations according to the third embodiment. A system selection unit 20 and a minimization configuration selection unit 21 that selects a system configuration with the minimum power transmission loss among the system configurations with the minimum power transmission loss calculated based on all initial system configurations, according to the second embodiment. Embodiments applied to are also included.

  Specifically, in the second embodiment, in STEP 601, the data reading unit 10 receives data such as the configuration of the power distribution system from the storage unit 3, the open / close state of the switch provided in the system, and data on the load and impedance. The system information data is read, and as an initialization process, the initial system generation unit 19 creates a plurality of different system configurations, and calculates the initial transmission loss for each system configuration through the transmission loss calculation unit 11.

  Then, the initial system selection unit 20 selects a new system configuration that has not been selected from among the plurality of initial system configurations created by the initial system generation unit 19, and the steps from STEP602 to 612 are performed based on the initial system configuration. Processing is executed. In STEP612, when the switch number changing unit 18 determines that the number of switches selected by the “closed” switch selecting unit 12 is equal to a preset n (predetermined threshold) (YES in STEP612) ), The initial system selection means 20 determines whether there is another initial system configuration that has not been subjected to the power transmission loss minimization process.

  When it is determined by the initial system selection unit 20 that there is another initial system configuration that has not been subjected to the power transmission loss minimization process, the initial system selection unit 20 includes a plurality of items created by the initial system generation unit 19. By selecting a new system configuration that is not selected from among the initial system configurations, the processing from STEPs 602 to 612 is repeated.

  When it is determined by the initial system selection means 20 that no other initial system configuration exists, in STEP 613, the minimized configuration selection means 21 includes the transmission loss calculated based on all the initial system configurations. The system configuration having the minimum power transmission loss is selected, the selected system configuration and the power transmission loss are output as the minimum power transmission loss system configuration and the minimum power transmission loss, and the process ends.

The block block diagram of the determination apparatus of the minimum power transmission loss system | strain structure which concerns on the 1st Embodiment of this invention. The figure which shows the processing flow of the determination apparatus of the minimum power transmission loss system structure which concerns on the 1st Embodiment of this invention. The figure (1) explaining the determination process of the minimum power transmission loss system structure by this invention. The figure (2) explaining the determination process of the minimum power transmission loss system structure by this invention. The block block diagram of the determination apparatus of the minimum power transmission loss system structure which concerns on the 2nd Embodiment of this invention. The figure which shows the processing flow of the determination apparatus of the minimum power transmission loss system | strain structure which concerns on the 2nd Embodiment of this invention. The block block diagram of the determination apparatus of the minimum power transmission loss system | strain structure which concerns on the 3rd Embodiment of this invention. The figure which shows the processing flow of the determination apparatus of the minimum power transmission loss system structure which concerns on the 3rd Embodiment of this invention. The figure which shows an example of a power distribution system. The figure which shows an example of calculation of the transmission loss of a distribution system. The figure which shows the some system structure based on the switching state of the switch of a power distribution system. The figure which shows the power transmission loss of the several system structure based on the switching state of the switch of a distribution system. The figure (1) which shows the minimum transmission loss determination process of the distribution system by the branch exchange method which is a prior art. The figure (2) which shows the minimum transmission loss determination process of the distribution system by the branch exchange method which is a prior art. The figure (3) which shows the minimum transmission loss determination process of the distribution system by the branch exchange method which is a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Calculation means 2 ... Input means 3 ... Storage means 4 ... Switch 4 ... Display means 6 ... Distribution system monitoring control apparatus 7 ... Distribution system
9a to 9g ... Section number 10 ... Data reading means 11 ... Transmission loss calculation means 12 ... "Closed" switch selection means 13 ... Power flow calculation means 14 ... "Open" switch selection means 15 ... Transmission loss reduction determination means 16 ... Initial System comparison means 17 ... Loss minimization configuration update means 18 ... Switch number change means 19 ... Initial system generation means 20 ... Initial system selection means 21 ... Minimization configuration selection means 91 to 95 ... Switches

Claims (13)

Among the system configurations in which the switching state of the switch is changed, a determination device for the minimum transmission loss system configuration for determining the minimum transmission loss system configuration that minimizes the transmission loss,
Closed switch selection means for selecting two or more open switches from a plurality of switches to be closed so as to create one mesh system in the system configuration,
Open switch selection means for selecting the number of switches in the closed state as many as the number of switches selected by the closed switch selection means to be opened so as to obtain a radial system configuration;
Each system configuration in which the switch in the open state selected by the closed switch selection means is changed to the closed state, and the switch in the closed state selected by the open switch selection means is changed to the open state A transmission loss calculation means for calculating the transmission loss of
A reduction determination means for determining whether the transmission loss of the predetermined system configuration calculated by the power transmission loss calculation means is less than the power transmission loss of another system configuration calculated earlier;
An update unit that updates a system configuration having a reduced transmission loss as a minimum transmission loss system candidate when it is determined to be reduced by the reduction determination unit;
Determining means for determining the minimum transmission loss system configuration from the minimum transmission loss system candidates;
With
The determination means is such that the reduction determination means does not reduce any of the transmission losses of each system configuration calculated by the transmission loss calculation means than the transmission loss of the minimum transmission loss system candidate in the latest updated state. And determining the minimum power transmission loss system candidate as the minimum power transmission loss system configuration.   2. The minimum transmission loss system configuration according to claim 1, wherein the open switch selection unit sequentially selects a switch in a closed state with a minimum passing current among the switches in the mesh system. Decision device.   3. The minimum transmission loss system according to claim 2, wherein the open switch selection unit sequentially selects a switch in a closed state with a minimum passing current under a capacity restriction of a transmission line of the system. Configuration determination device.   2. The apparatus for determining a minimum power transmission loss system configuration according to claim 1, further comprising limiting means for limiting a selected number of switches in an open state selected by the closed switch selecting means. Among the system configurations in which the switching state of the switch is changed, a determination device for the minimum transmission loss system configuration for determining the minimum transmission loss system configuration that minimizes the transmission loss,
Closed switch selection means for selecting a switch in an open state from a plurality of switches to be closed so as to create one mesh system in the system configuration,
Switch number changing means for changing the number of switches selected by the closed switch selecting means;
Open switch selection means for selecting the number of switches in the closed state as many as the number of switches selected by the closed switch selection means to be opened so as to obtain a radial system configuration;
Each system configuration in which the switch in the open state selected by the closed switch selection means is changed to the closed state, and the switch in the closed state selected by the open switch selection means is changed to the open state A transmission loss calculation means for calculating the transmission loss of
A reduction determination means for determining whether the transmission loss of the predetermined system configuration calculated by the power transmission loss calculation means is less than the power transmission loss of another system configuration calculated earlier;
An update unit that updates a system configuration having a reduced transmission loss as a minimum transmission loss system candidate when it is determined to be reduced by the reduction determination unit;
Determining means for determining the minimum transmission loss system configuration from the minimum transmission loss system candidates;
With
The determination means is such that the reduction determination means does not reduce any of the transmission losses of each system configuration calculated by the transmission loss calculation means than the transmission loss of the minimum transmission loss system candidate in the latest updated state. And determining the minimum power transmission loss system candidate as the minimum power transmission loss system configuration.   The switch number changing unit is configured to select the closed switch selection unit when the reduction determination unit determines that the transmission loss of the predetermined system configuration is not reduced more than the power transmission loss of another system configuration calculated previously. The apparatus for determining the minimum power transmission loss system configuration according to claim 5, wherein the number of switches to be selected is increased. An initial system generation means for generating a plurality of initial systems by randomly changing the switching state of the switch,
The closed switch selection unit selects a switch in an open state so as to create one mesh system in each initial system generated by the initial system generation unit. 5. The apparatus for determining the minimum transmission loss system configuration according to 5. Among the system configurations in which the switching state of the switch is changed, the minimum transmission loss system configuration determination method for determining the minimum transmission loss system configuration that minimizes the transmission loss,
A closed switch selection step of selecting two or more open switches from a plurality of switches to be closed so as to create one mesh system in the system configuration;
An open switch selection step for selecting the number of switches in the closed state equal to the number of switches selected in the closed switch selection step to be in an open state so as to obtain a radial system configuration;
Each system configuration in which the switch in the open state selected in the closed switch selection step is changed to the closed state, and the switch in the closed state selected in the open switch selection step is changed to the open state A transmission loss calculation step for calculating the transmission loss of
A reduction determination step for determining whether the transmission loss of the predetermined system configuration calculated by the power transmission loss calculation step is less than the power transmission loss of another system configuration calculated earlier;
An update step of updating a system configuration having a reduced transmission loss as a minimum transmission loss system candidate when it is determined to be reduced by the reduction determination step;
A determination step for determining a minimum transmission loss system configuration from minimum transmission loss system candidates;
Including
The determination step is the reduction determination step, and none of the transmission losses of each system configuration calculated by the transmission loss calculation step is reduced more than the transmission loss of the minimum transmission loss system candidate in the latest updated state. And determining the minimum transmission loss system configuration as the minimum transmission loss system configuration, when determining that the minimum transmission loss system configuration.   9. The minimum transmission loss system configuration according to claim 8, wherein the open switch selection step sequentially selects a switch in a closed state with a minimum passing current among the switches in the mesh system. Decision method. Among the system configurations in which the switching state of the switch is changed, the minimum transmission loss system configuration determination method for determining the minimum transmission loss system configuration that minimizes the transmission loss,
A closed switch selection step of selecting a switch in an open state from a plurality of switches to be closed so as to create one mesh system in the system configuration; and
A switch number changing step for changing the number of switches selected by the closed switch selection step;
An open switch selection step for selecting the number of switches in the closed state equal to the number of switches selected in the closed switch selection step to be in an open state so as to obtain a radial system configuration;
Each system configuration in which the switch in the open state selected in the closed switch selection step is changed to the closed state, and the switch in the closed state selected in the open switch selection step is changed to the open state A transmission loss calculation step for calculating the transmission loss of
A reduction determination step for determining whether the transmission loss of the predetermined system configuration calculated by the power transmission loss calculation step is less than the power transmission loss of another system configuration calculated earlier;
An update step of updating a system configuration having a reduced transmission loss as a minimum transmission loss system candidate when it is determined to be reduced by the reduction determination step;
A determination step for determining a minimum transmission loss system configuration from minimum transmission loss system candidates;
Including
The determination step is the reduction determination step, and none of the transmission losses of each system configuration calculated by the transmission loss calculation step is reduced more than the transmission loss of the minimum transmission loss system candidate in the latest updated state. And determining the minimum transmission loss system configuration as the minimum transmission loss system configuration, when determining that the minimum transmission loss system configuration.   When the switch number changing step determines that the transmission loss of a predetermined system configuration is not reduced more than the power transmission loss of another system configuration previously calculated by the reduction determination step, the closed switch selection step The method of determining the minimum transmission loss system configuration according to claim 10, wherein the number of switches to be selected is increased. Including an initial system generation step of generating a plurality of initial systems by randomly changing the switching state of the switch,
9. The closed switch selection step selects a switch in an open state so as to create one mesh system in each initial system generated by the initial system generation step. 10. The method for determining the minimum transmission loss system configuration according to 10. A determination program for a minimum transmission loss system configuration that causes a computer to determine a minimum transmission loss system configuration that minimizes transmission loss among the system configurations in which the switching state of the switch is changed,
In the computer,
A closed switch selection process for selecting two or more open switches from a plurality of switches to be closed so as to create one mesh system in the system configuration;
An open switch selection process for selecting the number of switches in the closed state equal to the number of switches selected by the closed switch selection process to be opened so that a radial system configuration is obtained; and
Each system configuration in which the switch in the open state selected by the closed switch selection process is changed to the closed state, and the switch in the closed state selected by the open switch selection process is changed to the open state Transmission loss calculation processing for calculating the transmission loss of
A reduction determination process for determining whether the power transmission loss of the predetermined system configuration calculated by the power transmission loss calculation process is less than the power transmission loss of another system configuration calculated earlier;
An update process for updating a system configuration having a reduced transmission loss as a minimum transmission loss system candidate when it is determined to be reduced by the reduction determination process;
A decision process for determining the minimum transmission loss system configuration from the minimum transmission loss system candidates;
And execute
The determination process is the reduction determination process, and none of the transmission losses of each system configuration calculated by the transmission loss calculation process is reduced more than the transmission loss of the minimum transmission loss system candidate in the latest updated state. And determining a minimum transmission loss system configuration as a minimum transmission loss system configuration, the minimum transmission loss system configuration determination program.

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