Power exchange systems, power exchange methods, power exchange programs

Abstract

To prevent a new power failure block from being generated during a switching step of a power failure recovery switch configuration in a power distribution system.SOLUTION: A method includes: constructing a data structure of ZDD obtained by compressing all switch configurations of a power distribution system and defining a set, which includes all blocks in the case of accident and does not include a failure location from the data structure of ZDD as an executable solution set ZDD S02; executing a "add operation" and a "safety swap operation" regarding each switch configuration in S01 represented by ZDD and performing a sum set operation of results of both the operations S03; and performing a common set arithmetic of a result of the sum set arithmetic and the solution set ZDD, thereby performing operations with respect to a switch configuration obtained by n+1 moves and obtaining all the switch configurations which can be changed over by the n+1 moves. By repeating this, the switch configuration including all the blocks, namely, the switch configuration in which all the blocks are electrified or the switch configuration in which the maximum number of blocks or the power failure amount is minimum is stored in a changeover procedure storage section 5 and executed.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a power supply technology in the distribution system of general power transmission and distribution operators.

Background Art

[0002] The power supply path in the distribution system forms a radial system according to the open / closed state (switch configuration) of the switchgear. When an accident such as a power outage occurs in the distribution system or when a planned power outage is carried out for construction or the like, power supply from the normal path becomes impossible.

[0003] Therefore, power supply from another path is required. At this time, by changing the switch configuration, “another path” for supplying power from the surrounding area is calculated. As such a method, the technologies of Patent Document 1 and Non-Patent Documents 1 and 2 are known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

[0006] Patent Document 1 checks whether a supply point is connected to multiple demand points based on system configuration data, and if connected, divides the supply point into predetermined virtual supply points and sets the total supply amount of the virtual supply points to match that of the supply point. However, Patent Document 1 does not take into account multi-stage flexibility in a tree structure, and there was a possibility that many power outage locations would remain.

[0007] In this regard, Non-Patent Document 1 describes a data structure called a zero-suppression type binary decision graph (hereinafter referred to as ZDD) which makes it possible to compress and store all possible switch configurations in a power distribution system. While this makes it possible to determine a switch configuration for power outage recovery that also takes multi-stage switching into consideration, it did not provide a procedure for switching from the switch configuration during a power outage to the switch configuration for power recovery.

[0008] Therefore, Non-Patent Literature 2 uses the ZDD data structure to calculate a switch configuration for power outage recovery that takes multi-stage flexibility into account, and simultaneously determines the switching procedure to that switch configuration. Here, the switching procedure is calculated by defining add and swap operations for the ZDD data structure.

[0009] However, the switching procedure to the power outage recovery switch configuration calculated by this technology may create new power outage periods along the way, which could pose problems for practical application.

[0010] This invention was made to solve the aforementioned conventional problems, and its objective is to prevent the generation of new power outage sections during the switching procedure of the power outage recovery switch configuration in a power distribution system. [Means for solving the problem]

[0011] (1) One aspect of the present invention is a power exchange system for a power distribution system equipped with a plurality of switches, A system equipment data unit that holds information about the aforementioned power distribution system, A calculation processing unit that acquires the information held by the aforementioned system equipment data unit and calculates the procedure for restoring power outages, A switching procedure storage unit that stores the switching procedure after the power outage is restored, Equipped with, The aforementioned arithmetic processing unit is From the data structure of the zero-suppression type binary decision graph (hereinafter referred to as ZDD) which compresses all the switch configurations of the aforementioned power distribution system, a set is extracted that includes all sections that are energized at the time of the fault but does not include the fault location, and the extracted set is made into a feasible solution set. For each switch configuration that can be switched by n (an integer greater than or equal to n) hands, represented by the ZDD data structure, an add operation and a swap operation are performed. By executing the above add operation, the switch is changed from the open state to the closed state, and the data structure of the ZDD is rebuilt. If the swap operation does not result in a fault, the switch is changed from the open state to the closed state, and another switch is changed from the closed state to the open state to reconstruct the data structure of the ZDD. By performing a union operation on the results of the add operation and the swap operation, and then performing an intersection operation on the solution set and the union, we obtain a set of switch configurations that can be switched in n+1 steps. The acquired set is stored in the switching procedure storage unit. The system is characterized by executing the open / closed state of the switch stored in the aforementioned switching procedure storage unit.

[0012] (2) Another aspect of the present invention is a system equipment data section that holds information on a power distribution system equipped with a plurality of switches, an arithmetic processing section that acquires the information held by the system equipment data section and calculates the power restoration procedure, a switching procedure storage section that holds the switching procedure after power restoration, and a method of executing a power distribution system power supply system including: wherein the arithmetic processing section extracts a set that includes all the energized sections during an accident and does not include the failure location from the data structure of a zero-suppressed binary decision diagram (hereinafter referred to as ZDD) that compresses all the switch configurations of the power distribution system, and sets the extracted set as an executable solution set; for each switch configuration that can be switched in n (n is an integer greater than or equal to 0) steps represented by the ZDD data structure, executes an add operation and a swap operation, by executing the add operation, changes the switch from the open state to the closed state and remodifies the ZDD data structure, by executing the swap operation, only when no accident has occurred, changes the switch from the open state to the closed state and changes another switch from the closed state to the open state and remodifies the ZDD data structure, executes a union operation on the results of the add operation and the swap operation; [[ID=二十]]by performing an intersection operation between the solution set and the union set, obtains a set of switch configurations that can be switched in n + 1 steps; holds the obtained set in the switching procedure storage section, and executes the open / closed states of the switches held in the switching procedure storage section.

[0013] (3) Note that the present invention can also be configured as a program characterized by causing a computer to function as the power supply system.

Advantages of the Invention

[0014] According to the present invention, it is possible to prevent the occurrence of a new power outage section during the switching procedure of the power outage restoration switch configuration in the power distribution system.

Brief Description of the Drawings

[0015] [Figure 1] A diagram showing an example of a power distribution system. [Figure 2] The switch configuration of FIG. 1. [Figure 3] The compressed representation diagram of Non-Patent Document 1. [Figure 4] (a) is the switch configuration diagram of ZDD that satisfies only the radial constraint of FIG. 1, (b) is the switch configuration diagram of ZDD that satisfies only the line capacity constraint, (c) is the switch configuration diagram of ZDD that satisfies only the voltage constraint, and (d) is the switch configuration diagram showing the result of the common set operation of all of (a) to (c). [Figure 5] The configuration diagram of the power supply sharing system according to the present embodiment. [Figure 6] (a) is the switch configuration diagram of ZDD, and (b) is the switch configuration diagram of the present embodiment. [Figure 7] The switch configuration diagram showing the state where a failure has occurred at e4 in FIG. 6. [Figure 8] (a) is the switch configuration diagram before the construction of the executable solution set ZDD, and (b) is the switch configuration diagram after the construction. [Figure 9] (a) is the switch configuration diagram before the "safe swap operation", and (b) is the switch configuration diagram after the operation. [Figure 10] The overall processing diagram. [Figure 11] The repetitive state diagram of FIG. 10.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, a power supply sharing system (method) according to an embodiment of the present invention will be described. This power supply sharing system provides an algorithm for power supply sharing calculation in the power distribution system of a general power transmission and distribution company, and aims to search for a switch configuration capable of supplying power and calculate a switching procedure when an accidental power outage occurs in the power distribution system or when a planned power outage is performed due to construction or the like.

[0017] ≪ZDD≫ (1) The power exchange system utilizes ZDDs described in Non-Patent Documents 1 and 2. A ZDD is a data structure that compresses and represents a "set of combinations". A ZDD will be explained based on the distribution system examples in Figures 1 and 2.

[0018] Figure 2 shows all the switch configurations in the power distribution system shown in Figure 1. That is, in Figure 2, "s i Each circle (node) labeled "s" is a switch in the power distribution system. i Corresponds to node "s i If the arrow coming out of " is a solid line, then the switch "s i This indicates that the switch is in the closed position, and if it is a dotted line, the switch "s i This indicates that it is in an open state.

[0019] Furthermore, the two squares 10 and 11 at the bottom of Figure 2 indicate that one square, 10, satisfies the constraint, while the other, 11, does not. Therefore, traversing the nodes in Figure 2 from top to bottom corresponds to determining one switch configuration for the power distribution system in Figure 1, and whether that switch configuration satisfies the constraint can be expressed by which square, 10 or 11, is reached.

[0020] When storing switch configurations using the method shown in Figure 2, the amount of data becomes enormous. Furthermore, this data storage method contains a lot of redundant information, such as storing the state of switches that clearly do not satisfy the constraints. Non-patent document 1 eliminates such redundancy and compresses the data, making it possible to efficiently calculate and store data for all switch configurations that satisfy the constraints (see Figure 3). This compressed data representation is a characteristic of ZDD.

[0021] Furthermore, ZDDs can perform union and intersection operations. For example, in the system shown in Figure 1, suppose all switch configurations satisfying only the radial constraint are held in the ZDD shown in Figure 4(a), all switch configurations satisfying only the line capacitance constraint are held in the ZDD shown in Figure 4(b), and all switch configurations satisfying only the voltage constraint are held in the ZDD shown in Figure 4(c).

[0022] At this point, the ZDD shown in Figure 4(d), obtained as a result of performing all intersection operations, holds all switch configurations that simultaneously satisfy the three constraints: radial constraints, line capacitance constraints, and voltage constraints.

[0023] The radial constraint is a restriction designed to minimize power outages in the event of an accident, by ensuring that every section of the power distribution system receives power from only one switch. Generally, power distribution systems in Japan operate using a radial system configuration.

[0024] Line capacity constraints are limitations imposed to prevent thermal degradation and damage to power lines by ensuring that the current of each line within a power distribution system remains below its permissible limit.

[0025] Voltage constraints are limitations imposed to ensure that each point in a power distribution system remains within its permissible voltage range, thereby preventing degradation and destruction of connected loads due to overvoltage and reduced performance due to undervoltage.

[0026] (2) Based on these ZDD technologies, Non-Patent Document 1 calculated all switch configurations of the power distribution system as ZDD. Therefore, this ZDD also includes the switch configuration for power outage recovery, taking into account multi-stage switching. However, this ZDD only maintains the switch configuration, and as mentioned above, it does not provide a procedure for switching from the switch configuration during a power outage to the switch configuration for power outage recovery.

[0027] Non-Patent Document 2 solves this problem. Non-Patent Document 2 develops two new operations in ZDD, namely "add operation" and "swap operation." These correspond to the following operations in ZDD, which maintains the switch configuration of the power distribution system.

[0028] In other words, the "add operation" is equivalent to changing one switch from the open state to the closed state for each switch configuration represented by the ZDD, thereby reconstructing the ZDD.

[0029] The "swap operation" corresponds to the operation of changing one switch from the open state to the closed state and simultaneously changing another switch from the closed state to the open state for each switch configuration represented by the ZDD, thereby reconstructing the ZDD.

[0030] These calculations made it possible to represent the switching procedure of the switch configuration using ZDD, but the switching procedure to the power outage recovery switch configuration calculated by this technology risked generating a new power outage period along the way. Therefore, the power exchange system of this embodiment has constructed a switching procedure that does not generate a new power outage period along the way.

[0031] System Details (1) Example configuration In Figure 5, 1 represents the power exchange system. Here, the power exchange system 1 is composed of a computer and is equipped with the hardware resources of a normal computer (CPU, RAM, ROM, HDD, SSD, etc.).

[0032] As a result of the collaboration of hardware and software resources (OS, applications, etc.), the power exchange system 1 implements a grid equipment data unit 2, a ZDD calculation processing unit 3, a grid equipment data unit 4 after recovery, and a switching procedure storage unit 5, as shown in Figure 5. Each of these units 2, 4, and 5 is built on a storage device (RAM, ROM, HDD, SSD, etc.).

[0033] Specifically, the system equipment data unit 2 holds information on switches in the power distribution system, while the system equipment data unit 4 and the switching procedure storage unit 5 each hold the system equipment data and switching procedure after the power outage is restored, respectively. Furthermore, the ZDD calculation processing unit 3 plays a central role in the power exchange system 1, acquiring the information (storage data) held by the system equipment data unit 2 and calculating the procedure for restoring power from the power outage.

[0034] (2) Method for calculating power outage restoration procedure The processing details of the ZDD calculation processing unit 3 will be explained based on the power distribution system in Figure 6. In Figure 6, 20 represents a substation, with switches represented by line segments (e1, e2, e3, e4, e5, e6) and sections represented by circles (v1, v2, v3, v4).

[0035] In the ZDDs described in Non-Patent Documents 1 and 2, the switch configuration (link variables) was represented by a set of closed switches. In this case, the data structure is {e1, e2, e3, e4}, as shown in Figure 6(a).

[0036] In response to this, the ZDD arithmetic processing unit 3 of this embodiment creates a new data structure (link node variable) in which the information of the power supply section is added to the information in Figure 6(a) beforehand. In this case, the data structure is {e1, e2, e3, e4, v1, v2, v3, v4} as shown in Figure 6(b). By adding the information of the power supply section in this way, it becomes possible to determine whether there is a power outage or whether there is a faulty section. The processing steps (S01 to S04) for calculating the power outage restoration procedure will be explained below based on Figure 10.

[0037] S01: This is a ZDD with a switch configuration that can be switched in n (an integer greater than or equal to n) steps from the initial switch configuration. The initial switch configuration (a switch configuration that can be switched in 0 steps) is the switch configuration obtained by removing the faulty parts from the initial solution.

[0038] S02: From the system data, construct a ZDD with radial constraints that allow for power outages, a ZDD with line capacity constraints, and a ZDD with voltage constraints. Perform an intersection operation on these to construct a ZDD that satisfies all constraints. From the constructed ZDD that satisfies all constraints, extract a set that includes all sections that are not power outages (i.e., energized) during an accident, and that does not include any fault locations. This set is the executable solution set ZDD. Here, the radial constraint that allows for power outages means that sections containing supply points satisfy the radial constraint, and power outages are isolated points.

[0039] For example, if a fault occurs at (e4) as shown in Figure 7, (e4) becomes the fault location, (v4) becomes the power outage section, and a switch configuration (S01) that can be switched with 0 moves is obtained. Then, as shown in Figure 8, a set is extracted that includes all sections that are not power outage sections (i.e., are energized) during the fault, and does not include the fault location, which is "a set that includes (v1), (v2), and (v3), and does not include (e4)". The extracted set is then used to construct a ZDD (S02) as a viable solution set.

[0040] In this case, switch configuration a1 in Figure 8(a) does not include (v2), so it is deleted as shown in Figure 8(b). Switch configuration a3 includes (e4), so it is similarly deleted.

[0041] On the other hand, switch configuration a2 satisfies the condition that it "includes (v1), (v2), and (v3), but does not include (e4)," and is therefore extracted as the solution set ZDD. The feasible solution set ZDD thus extracted is the set of switch configurations that are allowed when power is restored after an outage.

[0042] S03: In addition to the "add operation" described in Non-Patent Documents 1 and 2, a "safe swap operation" is performed, and the ZDD is calculated by applying the union (OR) operation of both operations.

[0043] To explain "safe swap operation" here, for each switch configuration represented by the ZDD of S01, the operation involves changing one switch from the open state to the closed state and simultaneously changing another switch from the closed state to the open state, as long as no new power outage is caused, thereby reconstructing the ZDD.

[0044] For example, looking at switch configuration a1 in Figure 9(a), if we set "(e4) closed and (e3) open," a new power outage occurs at (v3), as shown in Figure 9(b), so the switch configuration obtained by this swap calculation is removed. On the other hand, if we set "(e6) closed and (e3) open," no new power outage occurs, so the resulting switch configuration is included in the ZDD obtained by the "safe swap calculation." Similarly, the same applies to switch configuration a2, where "(e5) closed and (e6) open" does not cause a power outage.

[0045] In S04, the ZDD obtained from the union operation (OR) in S03 is combined with the executable solution set ZDD from S02 and the intersection operation (AND) is performed, and the result is stored in the switching procedure storage unit 5. This provides a set of switch configurations that can be switched in a single step.

[0046] At this time, as shown in Figure 11, by performing the above calculations for each switch configuration that can be switched in n steps, all switch configurations that can be switched in n+1 steps are obtained. By repeating this process, if a switch configuration that includes all sections, i.e., a switch configuration in which all sections are energized, is obtained, executing this configuration completes the power outage restoration. If multiple switch configurations are obtained, only one of the switch configurations should be executed. The switch configuration to be executed is stored in the system equipment data unit 4 after restoration.

[0047] Therefore, the power exchange system 1 can prevent the occurrence of "new power outages during the switching process," which was a problem in Non-Patent Literature 2. However, if such a switch configuration cannot be obtained despite searching all feasible solution sets ZDD, the switch configuration that maximizes the number of sections (i.e., minimizes the number of nodes where power outages occur during restoration) or minimizes the amount of power outage (total power outage time) is stored in the switching procedure storage unit 5 as the solution and executed. In this case as well, the effect of minimizing power outage sections / durations during the switching process can be obtained.

[0048] It should be noted that the present invention is not limited to the embodiments described above, and can be implemented with modifications within the scope of each claim. For example, the present invention can be configured as a program that causes a computer to function as the power exchange system 1.

[0049] A computer on which this program is installed will execute steps S01 to S04 as the aforementioned power exchange system. This program can be distributed by downloading it from the internet or by storing it on a storage medium. [Explanation of symbols]

[0050] 1…Power exchange system 2…System Equipment Data Department 3…ZDD processing unit 4…Data section of the system equipment after restoration 5…Switching procedure storage section 20... Substation

Claims

1. A power exchange system for a power distribution system equipped with multiple switches, A system equipment data unit that holds information about the aforementioned power distribution system, A calculation processing unit that acquires the information held by the aforementioned system equipment data unit and calculates the procedure for restoring power outages, A switching procedure storage unit that stores the switching procedure after the power outage is restored, Equipped with, The aforementioned arithmetic processing unit is From the data structure of the zero-suppression type binary decision graph (hereinafter referred to as ZDD) which compresses all the switch configurations of the aforementioned power distribution system, a set is extracted that includes all sections that are energized at the time of the fault, but does not include the fault location, and the extracted set is made into a feasible solution set. For each switch configuration that can be switched by n (an integer greater than or equal to 0) hands, represented by the ZDD data structure, an add operation and a swap operation are performed. By executing the add operation, the switch is changed from the open state to the closed state, and the data structure of the ZDD is remodeled. As long as the execution of the swap operation does not cause a new power outage, the switch is changed from the open state to the closed state, and another switch is changed from the closed state to the open state, thereby reshaping the data structure of the ZDD. By performing a union operation on the results of the add operation and the swap operation, and then performing an intersection operation on the solution set and the union, a set of switch configurations that can be switched in n+1 steps is obtained. The acquired set is stored in the switching procedure storage unit. A power exchange system characterized by executing the open / closed state of a switch stored in the aforementioned switching procedure storage unit.

2. The above calculations are performed and the open / closed states are switched, and the calculations are repeated until a switch configuration is obtained in which the entire section is energized. The power exchange system according to claim 1, characterized in that it is the same as described in claim 1.

3. If a set of all sections being energized cannot be obtained, the switching procedure storage unit will retain the open / closed state with the maximum number of sections or the minimum amount of power loss. The power exchange system according to claim 1, characterized in that it is the same as described in claim 1.

4. The ZDD data structure has a radial constraint that minimizes the power outage section in the event of an accident by ensuring that each section receives power from only one switch, Line capacity constraints that keep the current of each line in the aforementioned power distribution system below the allowable current, Voltage constraints to keep each point within the aforementioned power distribution system within an acceptable voltage range, The power exchange system according to claim 1, characterized in that it simultaneously satisfies the conditions.

5. A system equipment data unit that holds information on a power distribution system equipped with multiple switches, A calculation processing unit that acquires the information held by the aforementioned system equipment data unit and calculates the procedure for restoring power outages, A switching procedure storage unit that stores the switching procedure after the power outage is restored, A method for implementing a power exchange system for a power distribution system, comprising: The aforementioned processing unit, The steps include: extracting a set from the data structure of a zero-suppression type binary decision graph (hereinafter referred to as ZDD) that compresses all the switch configurations of the aforementioned power distribution system, which includes all sections that are energized at the time of the fault but does not include the fault location, and making the extracted set a viable solution set; For each switch configuration that can be switched by n (an integer greater than or equal to 0) hands, represented by the ZDD data structure, an add operation and a swap operation are performed. By executing the add operation, the switch is changed from the open state to the closed state, and the data structure of the ZDD is remodeled. As long as the execution of the swap operation does not cause a new power outage, the switch is changed from the open state to the closed state, and another switch is changed from the closed state to the open state, thereby reshaping the data structure of the ZDD. The steps include: performing a union operation on the results of the add operation and the swap operation; The steps include obtaining a set of switch configurations that can be switched in n+1 steps by performing an intersection operation between the aforementioned solution set and the aforementioned union, The steps include: storing the acquired set in the switching procedure storage unit, and executing the open / closed state of the switch stored in the switching procedure storage unit; A method for exchanging power, characterized by having the following features.

6. A program characterized by causing a computer to function as a power exchange system according to any one of claims 1 to 4.

Images