CN105071395B - High voltage distribution network load transfer method based on supply path Boolean Search - Google Patents

Abstract

The invention discloses a high-voltage distribution network load transfer method based on power supply path logic search, which includes the following steps: obtaining the topology map of the current distribution network; judging whether there is load overload at the power point in the current distribution network; Obtain the directional constraint set, mutual exclusion constraint set and sequence constraint set formed by the closed-loop path of all power points; when performing load transfer operation on the power point with overload on the transfer path, it is necessary to satisfy the directional constraint set, Mutually exclusive constraint set and sequence constraint set; determine whether the overloaded power point completes the load transfer within the pre-transfer operation times: if the load transfer target is not completed, perform load shedding operation on the overloaded power point. By adopting the method, the load transfer can be performed automatically, and it is not necessary for dispatchers to frequently perform load transfer based on experience.

Description

Load transfer method of high-voltage distribution network based on logic search of power supply path

technical field

The invention relates to dispatch control in the field of distribution network, in particular to a method for load transfer of high-voltage distribution network based on logic search of power supply path.

Background technique

With the acceleration of urbanization in my country, the urban load represented by residents, financial industry and commerce, service industry, and high-end manufacturing has developed rapidly in recent years. However, due to many reasons such as channel constraints, lack of locations, delays in construction schedules, and construction obstructions, it is difficult for the construction of high-voltage distribution networks to ensure moderate advances in urban load growth in every part. During the peak period or during the maintenance and technical renovation of important equipment, the operational risks caused by insufficient capacity or uneven load have gradually emerged.

Coupled with the 220kV network congestion caused by the temporary stability of the transmission network section and the thermal stability limit, cities with high power supply density have to adopt frequent or even large-scale power transfer operations during peak hours to expand the actual support capacity of the power grid. This has brought a huge workload to the dispatchers. Due to the lack of calculation and analysis tools for the characteristics of the high-voltage distribution network, the dispatchers are dispatching based on years of accumulated operating experience or trial-and-error strategies. As a result, it is difficult to search for a relatively complete feasible solution set and optimization scheme during scheduling, and it may even bring potential risks due to large changes in power flow.

Contents of the invention

In view of the above-mentioned deficiencies in the prior art, the present invention provides a high-voltage distribution network load transfer method based on power supply path logic search that can automatically and accurately transfer the overload load of the power point.

For the above-mentioned deficiencies in the prior art, the technical solution adopted in the present invention is:

Provided is a high-voltage distribution network load transfer method based on power supply path logic search, which includes the following steps:

Obtain the topological structure and operating parameter information of the current distribution network;

Judging whether there is a load overload at the power point in the current distribution network:

If it exists, obtain the direction constraint set, mutual exclusion constraint set and sequence constraint set formed by all power point closed-loop paths through deep search;

Use a closed-loop path that simultaneously satisfies the direction constraint set, mutual exclusion constraint set and sequence constraint set to perform load transfer operation on the overloaded power point;

Judging whether the overloaded power point has completed the load transfer within the number of pre-transfer operations:

If the load transfer has not been completed, perform load shedding operations on the overloaded power points.

The beneficial effects of the present invention are: by collecting the topology and operating parameter information of the distribution network in real time, when there is a power point load overload situation, by searching for a closed-loop path that meets the requirements of each power point to transfer power, so that each power point The load is lower than its rated load. This method can automatically and accurately eliminate the load overload situation in the distribution network through load transfer, and does not require dispatchers to frequently perform load transfer operations based on experience.

After the overload load of the distribution network is transferred, some power points are loaded with too high loads, and some loads are relatively low. If the power points with higher loads are not adjusted in time, at the next moment, the load Higher power points are very likely to be overloaded, so after the overloaded power points are transferred, the method also adjusts the load of the power points of the entire distribution network to balance the load of each power point.

In the process of load transfer and load balancing, this method can record the number of scheduling operations (the number of power point adjustments during transfer) and the sequence of each power point scheduling operation, so that dispatchers can intuitively understand the load transfer. The specific operation conditions provided.

Description of drawings

Fig. 1 is a flowchart of a load transfer method for a high-voltage distribution network based on a logic search of a power supply path.

Fig. 2 is a schematic diagram of a topological structure of a high-voltage distribution network according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of the basic topology of a high-voltage distribution network according to another embodiment of the present invention.

detailed description

The specific embodiments of the present invention are described below so that those skilled in the art can understand the present invention, but it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes Within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are included in the protection list.

Referring to FIG. 1, FIG. 1 shows a flow chart of a high-voltage distribution network load transfer method based on power supply path logic search. As shown in FIG. 1, the method includes the following steps:

Obtain the topological structure of the current distribution network (refer to Figure 2) and operating parameter information; since the load on each power point in the distribution network will change at every moment, in order to avoid power point failure, ensure The normal operation of the power point needs to pay attention to the topological diagram of the high-voltage distribution network at any time. Once the power point with load overload is found, the load needs to be transferred out in time; and the load must be transferred when it depends on the topology and operation of the distribution network. The parameter information can grasp the load situation of the power point in real time.

Judging whether there is a load overload at the power point in the current distribution network:

If it exists, obtain the directional constraint set, mutual exclusion constraint set, and sequence constraint set formed by all power point closed-loop paths through deep search; when the power point is performing load transfer, not all power supply paths can transfer the load. Therefore, before load transfer, it is necessary to search for a closed-loop path that can transfer the load smoothly.

In one embodiment of the present invention, the specific acquisition method of the above sequence constraint set is:

Conduct an in-depth search on the power points in the current distribution network to obtain the distribution capacity unit of the main power supply; refer to Figure 3, the A station, B station, C station and D station shown in the figure are 220KV substations, these The substation is the power point mentioned in this method, (S1, 1), (S1, 2), (S2, 1), (S2, 2), (S3, 1), (S3, 2), (S4, 1 ) and (S4, 2) are the distribution capacity units in the distribution network (the distribution capacity unit is the combination of the transformer in the 110 kV substation and its load), and S1 is the 110kV substation for the main power supply of station A, and S4 is the The 110kV substation mainly supplied by Station B, and S3 is the 110kV substation mainly supplied by Station C.

Obtain the power supply path from the distribution capacity unit of the main power supply point to all power points in the distribution network through deep search; refer to Figure 3 again, take the distribution capacity unit (S2, 2) of station A as an example to supply power to it The path is described, among which, (S2, 2) → (S2, 1) → (S1, 2) → (S1, 1) → A, (S2, 2) → (S2, 1) → (S1, 2) → B. (S2, 2) → (S4, 1) → (S4, 3) → (S4, 1) → B, (S2, 2) → (S3, 1) → C, (S2, 2) → (S2 , 1) → (S1, 2) → (S1, 1) → C, (S2, 2) → (S3, 1) → (S3, 2) → D is the main power supply and distribution capacity unit (S2, 2) There are 6 power supply paths to all power supply points in total.

Combine the power supply paths from the distribution capacity unit to any two power points to form a closed-loop path; still take the main power distribution capacity unit (S2, 2) in Figure 3 as an example to illustrate the closed-loop path, and the distribution capacity unit ( S2, 2) The closed-loop path formed by merging the power supply paths to any two power supply points A and B is: A station → (S1, 1) → (S1, 2) → (S2, 1) → T S2, 2) → Station B, Station A → (S1, 1) → (S1, 2) → (S2, 1) → (S2, 2) → (S4, 1) → (S4, 3) → Station B.

Based on the principle of sequence constraints, the closed-loop paths that satisfy the sequence constraints are stored in the sequence constraint set; where the sequence constraints are: when the power distribution capacity unit on the same closed-loop path performs load transfer to the power point, the adjacent target power point The load transfer operation of the distribution capacity unit should precede the distribution capacity unit whose rear end is far away from the target power point.

The following takes the closed-loop path C station → S3 → D station of the distribution capacity unit S3 of the power point in Figure 3 as an example to further explain the sequence constraints. When (S3, 1) in S3 needs to transfer to station D When the load is transferred, (S3, 2) in S3 must be transferred to station D at the same time (S3, 1) in S3 can be transferred to station D.

In another embodiment of the present invention, the specific method for obtaining the above-mentioned direction constraint set is:

Based on the principle of directional constraints, the closed-loop paths that satisfy the directional constraints are stored in the directional constraint set; where the directional constraints are: when the same distribution capacity unit has two or more load transfer directions to choose from, it can only Choose a transfer path. Specifically: the power distribution capacity unit cannot transfer power to two or more power points at the same time.

The method of obtaining the mutually exclusive constraint set is: according to the closed-loop path of the power point, obtain each power point in the current distribution network and the power point that has a relationship with it; refer to Figure 2, taking station B as an example, the power points that have a relationship with it The power points are A station, C station, D station and E station.

Determine whether the power point and the power point in contact with it have the same power distribution capacity unit, specifically, station B → b3 → b4 → a6 → a5 → station A and station A → a5 → a6 → b4 → b3 → B station, the two closed-loop paths both have distribution capacity units consisting of b3, b4, a6, and a5, and a6 and b4 are the two most adjacent distribution capacity units connected through the backup path.

If so, based on the mutually exclusive constraint conditions, store the two most adjacent power distribution capacity units on the same closed-loop path connected by the backup path into the mutually exclusive constraint set.

Among them, the mutually exclusive constraint condition is: when the two most adjacent distribution capacity units on the same closed-loop path are connected through the backup path for load transfer, they cannot simultaneously transfer power to the two directions of the closed-loop path; That is to say, when the load transfer is from station B → b4 → station A, there shall be no load transfer from station A → a6 → station B or when the load transfer is from station A → a6 → station B, no load transfer shall occur Station B→b4→A station.

The main supply path mentioned above is the power supply path for the distribution capacity unit to obtain electric energy from the power point or other distribution capacity units, as shown in the two solid line paths of station A→a5 and a5→a6 in Figure 2.

The backup path is the power supply path where the distribution capacity unit may obtain power from other power points or other power distribution capacity units, but currently does not obtain power through it, as shown in the two dotted line paths of station A → a5 and a5 → a6 in Figure 2 .

Use the closed-loop path that satisfies the directional constraint set, mutual exclusion constraint set and sequence constraint set to perform load transfer operation on the overloaded power point; that is, the transfer path used in the load transfer must be in the direction constraint at the same time Sets, exclusive constraint sets, and closed-loop paths in sequence constraint sets.

Judging whether the load-overloaded power point has completed the load transfer within the number of pre-transfer operations (the number of pre-transfer operations can be set according to the number of times the dispatcher often performs transfers in the previous scheduling process):

When the power point completes the load transfer, or the power point does not complete the load transfer (that is, through this method for multiple transfer operations, the load on the power point is still overloaded), the load shedding operation is performed on the overloaded power point (In the case of ensuring the normal operation of the power point, it is necessary to forcibly shut down the load loaded on it) After that, the power point load transfer of the distribution network is completed.

After the power point load transfer operation of the distribution network is completed, although the load of each power point may not be overloaded, the load on some power points may be high and others may be very low. For the loaded load A very high power point is very likely to be overloaded when the load on it changes slightly. In order to avoid this phenomenon, after the load transfer is completed, it is necessary to balance the load on the power point .

The method also includes a step of judging whether the loads of all power points in the current distribution network are balanced:

If it is unbalanced, the closed-loop path that satisfies the direction constraint set, the mutual exclusion constraint set and the sequence constraint set at the same time is used to perform load transfer operation on the power point with unbalanced load until the load of all power points in the current distribution network is balanced.

In one embodiment of the present invention, in the process of load transfer and load balancing, in order to facilitate dispatchers to intuitively understand the specific operation of load transfer, when the loads of all power points in the current distribution network are balanced, it is also necessary Record the number of load transfer operations from the load overload of the power point to the load balancing process of all power points in the distribution network and the operation sequence of the power point when the load is transferred.

To sum up, this method can automatically transfer loads to overloaded power points, and does not require dispatchers to frequently perform load transfers based on experience.

Claims (7)

1. The high-voltage distribution network load transfer method based on power supply path logic search, is characterized in that, comprises the following steps: Obtain the topological structure and operating parameter information of the current distribution network; Judging whether there is a load overload at the power point in the current distribution network: If it exists, obtain the direction constraint set, mutual exclusion constraint set and sequence constraint set formed by all power point closed-loop paths through deep search; Use a closed-loop path that simultaneously satisfies the direction constraint set, mutual exclusion constraint set and sequence constraint set to perform load transfer operation on the overloaded power point; Judging whether the overloaded power point has completed the load transfer within the number of pre-transfer operations: If the load transfer has not been completed, perform load shedding operations on the overloaded power points. 2. The load transfer method for high-voltage distribution network according to claim 1, further comprising: when the load transfer is completed or after the load shedding operation is performed on the overloaded power point, it will enter the judgment of the current distribution network Whether the loads of all power points in the system are balanced; If it is unbalanced, the closed-loop path that satisfies the direction constraint set, the mutual exclusion constraint set and the sequence constraint set at the same time is used to perform load transfer operation on the power point with unbalanced load until the load of all power points in the current distribution network is balanced. 3. The high-voltage distribution network load transfer method according to claim 2, further comprising: When the load of all power points in the current distribution network is balanced, record the number of load transfer operations and the operation sequence of the power point when the load is transferred from the load overload to the load balance of all power points in the distribution network. 4. The load transfer method of high-voltage distribution network according to any one of claims 1-3, wherein the method for obtaining the sequence constraint set is: Conduct an in-depth search on the power points in the current distribution network to obtain the distribution capacity unit of the main power supply; Obtain the power supply path from the distribution capacity unit of the power point main supply to all power points in the distribution network through deep search; Merge the power supply path from the power distribution capacity unit to any two power points to form a closed-loop path; Based on the principle of sequence constraints, store the closed-loop paths that satisfy the sequence constraints into the sequence constraint set; Among them, the sequence constraints are: when the distribution capacity units located on the same closed-loop path perform load transfer to the power point, the load transfer operation of the distribution capacity unit adjacent to the target power point should be farther away from the target power point than its rear end distribution capacity unit. 5. The load transfer method of high-voltage distribution network according to claim 4, wherein the method for obtaining the directional constraint set is: Based on the principle of directional constraints, the closed-loop paths that satisfy the directional constraints are stored in the directional constraint set; where the directional constraints are: when the same distribution capacity unit has two or more load transfer directions to choose from, it can only Choose a transfer path. 6. The load transfer method of high-voltage distribution network according to claim 4, characterized in that, the acquisition method of the mutually exclusive constraint set is: According to the closed-loop path of the power point, obtain each power point in the current distribution network and the power point in contact with it; Judging whether the power point and the power point connected to it have the same power distribution capacity unit: If yes, store the two most adjacent power distribution capacity units connected by the backup path on the same closed-loop path into the mutually exclusive constraint set; Among them, the mutually exclusive constraint condition is: when the two most adjacent distribution capacity units on the same closed-loop path are connected through the backup path for load transfer, they cannot simultaneously transfer power to the two directions of the closed-loop path. 7. The load transfer method according to claim 5 or 6, wherein the power point is a 220 kV substation, and the distribution capacity unit is a combination of a transformer in a 110 kV substation and the load it carries.