JP2644753B2 - How to determine load interchange of distribution system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a method for determining a load interchange of a distribution system, and more particularly to a method of determining what kind of distribution line power should be supplied to each load section of a distribution line. The present invention relates to a method for determining a load interchange of a power distribution system, which is suitable for the above.

[Conventional technology]

Conventionally, as a load accommodation determination method for a distribution system, a first load accommodation determination method is a distribution line system in which a plurality of load sections to which power is to be supplied are interconnected and power can be supplied to this portion. If there is more than one, these load sections and the distribution system are calculated in a brute force combination, and those that match the distribution conditions are selected from these combinations, and the actual distribution system is selected based on this combination. Was controlling the switch.

In addition, the second method for determining load accommodation is as follows:
There is a method discussed in Japanese Patent Publication No. 12455 “Distribution line transmission method”. In this method, the above-mentioned brute force operation is not performed, and the distribution line to be interchanged is first sent back within a margin from the system of the connected substation, and then the interchange is carried out. In order to rescue the sections that could not be performed and to average the reserve capacity of each substation on the rescue side, adjustments were made by interconnecting substations so that the load on the substations with large power reserve capacity became large.

[Problems to be solved by the invention]

In the method based on the brute force combination of the first method described above,
A considerable amount of time is required for the combination calculation, and therefore, it takes a considerable amount of time to perform actual distribution line control.

In the second method, the process of deciding how to implement the interchange is simplified, and the actual operation of the switch is performed as early as possible. On the other hand, there are disadvantages such as the occurrence of a blackout section that cannot be accommodated, and the necessity of resuming the section for reverse transmission from another substation system in order to reduce the blackout. In addition, the time required for the entire load interchange including the switch operation is not simply determined from the interchange calculation, but also depends on the characteristics of the operated switch, for example, whether or not remote operation is possible. Immediately starting from the reverse delivery is not preferable.

An object of the present invention is to determine an appropriate distribution line for power supply at a high speed for each of the load accommodating sections connected to a plurality of distribution lines in various shapes, as compared with these conventional methods, and An object of the present invention is to provide a load interchange determination method that can minimize a power failure section.

[Means for solving the problem]

In order to achieve the above object, the present invention sets a distribution line section that can be connected to another distribution line via a distribution line switch as a flexible load section, and sets a distribution line section having at least one flexible load section as a distribution interchange target. A method for determining a load interchange of a distribution system that specifies a distribution line to be load-interchanged from a plurality of distribution lines that can be individually connected to a distribution bus for each of the interchange load sections in the distribution interchange target section as a section. A first calculation step of calculating whether or not electric power can be supplied from each of the plurality of distribution lines to each of the interchange load sections in the distribution interchange section; and a first calculation step, In the case of a specific interchange load section, if no power distribution section is required unless power is supplied through a specific load interchangeable distribution line, the non-power distribution section shall be supplied with power from a load interchangeable distribution line. A second calculation step of defining,
In the second calculation step, a new load distribution section adjacent to the load-capable distribution line in a load section other than the no-power distribution section on the path between the non-power distribution section and the load-capable distribution line is newly added. A third calculation step defining an electric wire;
By repeating the first, second, and third calculation steps, a distribution line that supplies power from a plurality of distribution lines is specified for each of the interchange load sections constituting the distribution interchange target section. It was made.

[Action]

Generally, as technical issues in the load accommodation determination method,
The challenge is to find out which adjacent distribution line system should supply power to each load section, and to find an optimal combination of the load section and each distribution line system. Therefore, if the system becomes large-scale, the number of combinations becomes enormous, and it takes a lot of processing time to extract combinations without care.

However, it has been found that the distribution line system that can be supplied to each load section is limited to some extent due to the upper limit of the remaining reserve capacity and the like. If one of the limited candidate distribution lines is selected based on the above-described calculation step, the distribution lines that are inevitable and can supply power will be allocated.
Nearly optimal combinations can be realized. As a result, high-speed processing for determining power supply can be performed without performing the combination calculation required many times, which has been performed by the conventional method, and the power failure section can be minimized.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a flow chart showing a procedure for determining an accommodation mode according to the present invention.

Normally, the distribution system is operated so as not to form a loop, that is, by connecting the load load sections in a tree shape. Thus, only the adjacent distribution line system can be assigned to the same load section.

By the way, it is usually better to sequentially select the load sections (not necessarily one) to which the rules of high necessity can be applied, rather than perform the allocation processing all at once at once. It is considered that more appropriate allocation is possible (the processing ends when the distribution line system to be allocated to the full load section is determined as shown in block 101). this is,
It can be said that this is appropriate in accordance with the tendency that the restriction of the loop prohibition increases as the processing proceeds.

Therefore, the allocated parts are sequentially removed from the to-be-processed load section to be processed and incorporated into the adjacent distribution system (at this time, the remaining reserve capacity of the distribution system is assigned. Reduce by the target section load). These interchange target load sections and the like are clearly modeled in the processing of block 102.

In block 103, an adjacent distribution line system that can be supplied to each load section is extracted, and based on this information, one of them is selected in block 104.

The case where the processing of FIG. 1 is applied to the distribution system of FIG. 2 will be described below.

In the system shown in FIG. 2, when a ground fault occurs in the load section 321 of the distribution line system connected to the bus via the circuit breaker, all the load sections connected to the circuit breaker 22 are blackout. However, the portion indicated by 300 surrounded by a broken line is the adjacent circuit breakers 21 and 23.
There is a possibility that a power outage can be avoided by load interchange from the distribution line system. The sub-system 30
0 is extracted as a distribution interchange target section. In order to facilitate the subsequent processing, as shown in FIG. 3, a flexible load section is a node, a switch capable of connecting the flexible load sections (nodes) is a branch, and a flexible load section (node). The adjacent distribution line system that can be connected is treated as a feeder, including the switch. The feeder differs from the branch as shown by the arrow, and has only one end as a node, and has the remaining reserve power of the flexible distribution line system as a capacity (value shown in parentheses). When the same feeder is connected to a plurality of nodes, the reserve in parentheses indicates the entire feeder. The distribution interchange target section is not limited to 300 in FIG.
For example, all systems may be used.

In FIG. 2, the value indicated in parentheses at the breaker indicates the capacity of the circuit breaker, and the value indicated at () in the load section indicates the load amount in the section. In FIG. 3, the load of the corresponding section is shown in the circle of the node, and the node number in the flexible portion of the extraction is shown in the small circle of the left shoulder or the right shoulder. The feeders are also renumbered F1 and F2 corresponding to the breakers 21 and 22, respectively.

The modeling of the flexible portion as described above is performed in block 102 of FIG. In the example of the system shown in FIG. 2, for simplicity of explanation, the switches of the branch and the feeder do not depend on the operation method (there is no difference).

Next, the limitation of the load section to be accommodated shown in the block 103 of FIG. 1 is performed. As shown in FIG. 4, the LSP for each feeder (tentative name: Shortest Load Path = shortest load path) is used.
Is calculated. The SLP is the minimum total load from the entrance node of the feeder to each node of interest (including the entrance node) within the capacity range of each feeder. If the SLP exists in the node of interest, the SLP is Indicates that supply is possible (necessary condition). Therefore, if there is no SLP of any feeder for a certain node, there is no choice but to supply power to that node and cause a power outage (sufficient condition for power outage).

As shown in FIG. 4 (1), in a state where all of them are unprocessed,
The feeder F1 can supply power to all nodes, and the F2 can supply power to all nodes except for F2. In the SLP, a supply route indicated by an arrow and a route total load amount described near the node are specified. Based on this SLP, the processing of block 104 in FIG. 1 is performed, and feeders are assigned to some nodes. That is, on the assumption that there is no power outage, F1 and on its only path
F1 is also assigned to the area adjacent to F1. If F2 is not available (as is F1), the available power of the feeder will be insufficient for the total load to be accommodated. Also, since there is only the entry node of F2, F2 is assigned assuming that there is no power failure.

The processed portion is removed from the target, the feeder capacity and the direct supply inlet node are corrected, and the portion shown in FIG.
Get SLP. From now on, only F2 can be supplied, and F2 is assigned assuming no power outage. In the same manner, the result of the accommodation calculation as shown at the end of FIG. 4 is finally obtained.

Here, the above-mentioned rule will be supplemented below. An example of the only route of the rule (1) is the node shown in FIG. 4 (1) as described above. Here, the feeder F2 can also be assigned, but if this is the case, supply to F1 already assigned becomes impossible, and contradictions arise. Therefore, it is inevitably assigned to F1.

On the other hand, in the example shown in FIG. 5 (1), since the node can only be supplied from the feeder F1, even if F2 is assigned to the temporary route intermediate node after F1 is assigned, →→→ Since there is a route of →, it can be bypassed, and →→ is not the only route. Whether or not the temporary route is the only one is determined, for example, when the nodes on the temporary route are to be used repeatedly or provisionally allocated by another allocation by the feeder later (see FIG. 4 (1)). , FIG. 5 (1)) is temporarily removed, and it can be determined by checking whether or not there is an SLP to the previously allocated node.

However, depending on the connection shape of the node, it is possible to determine whether or not the route is the only route without calculating the SLP. Fig. 5 (2)
In the example system shown in Fig. 1, F1 is assigned to →
It is clear that the temporary route of → has no other branch and has no room for detour.

Next, an example in which the same feeder is allocated to another node in conjunction with the allocation is shown in FIG. 4 (3). The switch between the nodes is different from that of the other branches, and the characteristics of the operation are different depending on its orientation. That is, when is charged, it is automatically turned on after a certain time period. Conversely, even if the battery is charged, it does not automatically turn on, and requires an on operation. In addition,
In order not to automatically turn on after charging, it is necessary to lock in advance. Thus, assigning F1 to F1 means assigning F1 at the same time.

The assignment of the operation procedure of the rule (4) that requires less operation will be described with reference to an example of FIG. 5 (3). When a node connected by a switch having the above-mentioned characteristics can be supplied from both the feeders F1 and F2, one operation is sufficient if F1 is assigned to (although also), but F2 is assigned. And two operations are required. Therefore, it is better to start from F1.

Another embodiment of the present invention will be described with reference to FIG. As for the accommodation target shown in FIG. 6A, both the feeders F1 and F2 can be supplied to all nodes. Therefore, the node having the largest load is supplied from the feeder F1 using the rule (3) described above. Then, by a procedure similar to that described above, results as shown in (a-1) and (b-1) of FIG. 6 (2) are obtained. In this case, the sum of the power failure load amount and ( 4) Cannot be smaller. On the other hand, when F2 is assigned to the result, the results as shown in (a-2) and (b-2) are obtained, and the amount of power failure can be reduced by the amount of (2), and the solution is closer to the optimum. In addition, it is close to the optimum even in a point where the number of blackout sections is small.

As described above, there are cases where the power outage load amount cannot be minimized only by using the above-described rules, and the optimum solution is not always obtained. Therefore, even if it is obtained as (a-1) ((b-1)), if a necessary assignment is not performed (for example, assignment to the above), another candidate feeder is assigned. (As a result, (a-
2) A solution like ((b-2)) is obtained).

As described above, if the necessity of feeder allocation is managed by the application rule, it is convenient to check another combination, and it is possible to systematically check another combination by using the branch and bound method. Also, in the case of applying the branch and bound method, if the rule of the present invention is used and priority is given to assignment that is highly inevitable, a solution that is more optimal is obtained.
Modifications of the combination can be obtained early with little modification.

The improvement of the solution once obtained can be achieved by replacing the solution (supply feeder of the node) as follows, in addition to trying another allocation according to the processing procedure as described above. This will be described with reference to FIG.

In FIG. 6 (2) (b-1), the feeder F1 is connected to the node where the power failure has occurred, but the capacity is insufficient by one. Therefore, supply from F1 is stopped (FIG. 7 (1)), and supply is performed instead (FIG. 7 (2) F1 is used up to the supply capacity upper limit, and the amount of power failure is also reduced). Next, since it becomes possible to supply from F2, it is assigned as such. As a result, the power failure occurs only at the node (2) (FIG. 7 (3)).

This post-processing can be applied not only to the reduction of power failure due to the replacement of the feeder, but also to the improvement of the operability by switching the ON / OFF of the switch.

〔The invention's effect〕

As described above, according to the present invention, it is possible to obtain, as a quasi-optimal solution, a high-speed, low-power load as much as possible with respect to a flexible load section group of a distribution line that can be connected in various shapes. . That is, in the present invention, of the combinations of a large number of load sections and the adjacent distribution line system, a combination corresponding to a combination that is considered to be almost optimal is directly generated irrespective of the ratio of the combinations. Improving efficiency. Thus, the present invention, for example, has a reduced number of load sections of 1 when compared with the conventional technique of brute force processing.
0, the number of distribution lines system of adjacent and 3, the combination of brute power outage Include become those four types ¹⁰ and enormous. On the other hand, according to the present invention, there is no need for particularly time-consuming arithmetic processing, including calculations for determining the allocatable distribution line system, and the distribution system can be controlled at high speed.

[Brief description of the drawings]

FIG. 1 is a processing flow chart showing an embodiment of the present invention, FIG. 2 is a power distribution system diagram for explaining the embodiment, and FIG. 3 extracts portions particularly related to interchange calculation from FIG. FIG. 4, FIG. 4 is a diagram showing the processing status on a system diagram, FIG. 5 is a system diagram for supplementary explanation of the measures proposed in the present invention, and FIG. 6 and FIG. It is a system diagram etc. for explaining the Example of FIG. 20: Substation bus, 21 to 23: Circuit breaker, 31 to 33: Interconnected switch, 101 to 104: Processing block diagram, 211 to 234: Segmented switch, 300: Loaded load section Group system, 311 to 334: Flexible load section.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ryuzo Hirano 5-2-1 Omikamachi, Hitachi City Inside the Omika Plant, Hitachi, Ltd. (72) Inventor Shunji Unotsu 3-2-1 Sachimachi, Hitachi City No. Hitachi Engineering Co., Ltd. (56) References JP-A-59-21231 (JP, A) JP-A-61-203825 (JP, A) JP-A-62-92724 (JP, A)

Claims (1)

(57) [Claims] A distribution line section that can be connected to another distribution line via a distribution line switch is a flexible load section, and a distribution line section having at least one flexible load section is a distribution interchange target section. In the load interchange determination method of the distribution system for specifying a distribution line to be load interchanged among a plurality of distribution lines that can be individually connected to the distribution bus for each interchange load section in the interchange target section, A first calculation step of calculating whether electric power can be supplied from each of the plurality of distribution lines for each of the interchange load sections in the interchange target section, and, by the first calculation step, For a specific interchange load section, if a non-power distribution section is required unless power is supplied through a specific load interchangeable distribution line, the non-power distribution section may be supplied with power from the load interchangeable distribution line. A second calculation step defining the following, the second calculation step, on the path between the no-power distribution section and the load-capable distribution line, in a load section other than the no-power distribution section, The third calculation step of defining an accommodating load section adjacent to the load accommodating distribution line as a new distribution line, and the first, second, and third calculation steps are repeated to configure the distribution accommodating section. A distribution line for supplying electric power from the plurality of distribution lines for each of the interchange load sections to be performed.