CN114069689A - Three-stage topology operation optimization method based on load importance - Google Patents

Abstract

The embodiment of the application provides a three-stage topology operation optimization method based on load importance, which comprises the steps of collecting operation data of a power distribution network after a fault, and establishing a topology structure for fault identification; establishing a load importance evaluation model according to the power loss charge in the distribution network operation data; searching a distributed power generation device with adjustable power in a distribution network island region, and performing one-stage topology optimization; establishing a two-stage topological optimization model, and carrying out load transfer on the standby feeder line and the distributed power generation device; after load transfer is carried out, if a target substation in an overload operation state exists, a secondary transfer model is established, and the optimal transfer load of the target substation is obtained. The decision of the optimal operation mode of the distribution topology under the fault can be effectively processed, the power supply reliability of the power distribution network is improved, the maintenance mode of the power distribution network can be checked and optimized, the comprehensive analysis of the load of the power distribution network of the cloud platform can be favorably regulated and controlled, and the optimal utilization of the capacity of the power distribution network system can be favorably realized.

Description

Three-stage topology operation optimization method based on load importance

Technical Field

The application relates to the field of network optimization, in particular to a three-stage topology operation optimization method based on load importance.

Background

At present, methods related to topology operation mode optimization when a fault occurs include: the method comprises a load method, a main transformer interconnection transfer method and a comprehensive transfer matrix method, wherein secondary transfer and 'distribution on demand' of overload main transformers in a station are considered to improve the maximum transfer capacity and load balance degree of a distribution network, the topological operation mode is optimized according to the main transformer interconnection relation and an N-1 criterion, and the maximum load recovery amount is used as a target to transfer power failure load to other transformer stations through manual switching-on or distribution automatic switching action to achieve the optimal operation mode of station topology under faults; however, in the optimization process, the load importance and the influence of the access of the distributed energy on the topology optimization are not considered, so that the optimal topology operation mode decision under the fault is influenced.

Disclosure of Invention

The embodiment of the application provides a three-stage topology operation optimization method based on load importance, can effectively process the decision of a topology optimal operation mode under the fault, improves the power supply reliability of a power distribution network, and can check and optimize the maintenance mode of the power distribution network.

Specifically, the three-stage topology operation optimization method based on load importance provided by the embodiment of the present application includes:

s1, collecting operation data of the power distribution network after the fault, and establishing a topological structure for fault identification;

s2, establishing a load importance evaluation model according to the power loss electric charge in the distribution network operation data;

s3, searching a distributed power generation device with adjustable power in a distribution network island region, and performing one-stage topology optimization;

s4, establishing a two-stage topological optimization model, and carrying out load transfer on the spare feeder line and the distributed power generation device;

and S5, after the load transfer is carried out, if the target transformer substation in an overload operation state exists, establishing a secondary transfer model to obtain the optimal transfer load of the target transformer substation.

Optionally, the S1 includes:

collecting the number and positions of a transformer substation, a distribution transformer node, a connection feeder line, a breaker switch and a connection switch in a power distribution network;

constructing a topological structure according to the positions of the transformer substation, the distribution transformer node, the interconnection feeder line, the breaker switch and the interconnection switch, and adjusting the state of each device in the topological structure;

and determining the connection relation between the directly-connected transformer substation and the secondary connected transformer substation according to the adjusted topological structure.

Optionally, the S2 includes:

fitting power failure loss functions of different types of loads by adopting a minimum bisection method, and calculating a weight coefficient of the load by using the power failure loss function according to the load type and the estimated power failure duration, wherein the calculation formula is as follows:

in the formula, ω_i,tRepresents the weight coefficient, alpha, of the load i at the time of power failure t_iAnd beta_iThe fitting parameters of the load power failure loss function are determined by the characteristics of the load.

Optionally, the S3 includes:

for power-loss loads L1 and L2, no standby feeder is used for recovering power supply;

the distributed power generation device with continuous power regulation capability operates in an island mode to supply power to power loss loads L1 and L2.

Optionally, the S4 includes:

for the second-stage standby feeder line and the load of the distributed power generation device from grid connection to power loss, the power support of the grid-connected distributed power generation device is considered;

the load transfer result mainly comprises the recovery rate of the power-loss load, a transfer path and transfer time;

after the load transfer is completed, acquiring the load rate of the directly connected transformer substation;

and if the load rate is higher than a preset value, judging that the directly-connected transformer substation is in a dangerous operation state.

Optionally, the S5 includes:

according to the third-stage transfer model, a secondary transfer strategy is adopted, namely, the third-stage optimization is carried out to solve the problem that the load rate of the directly-connected transformer substation is too high;

and updating the load rate of the directly-connected substation in the dangerous operation state according to the optimization result, and repeating the iteration of the second-stage and third-stage optimization until the directly-connected substation in the dangerous operation state disappears or cannot perform secondary transfer.

Has the advantages that:

on one hand, the scheme considers the influence of the load importance degree on the optimization of the topology operation mode, and further improves the feasibility of the topology optimization decision; on the other hand, a three-stage topological operation optimization strategy is provided, normal power supply load on the weak link is transferred to other transformer substations, the power supply recovery amount of the power failure area is increased, the provided topological operation optimization mode can effectively guarantee stable operation of the distribution network system, and the superiority of the topological optimization mode is further improved.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a flowchart of a three-stage topology operation mode optimization considering load importance according to an embodiment of the present application;

FIG. 2 is a wiring diagram of an example power distribution network;

fig. 3 is a fitted graph of load importance.

Detailed Description

To make the structure and advantages of the present application clearer, the structure of the present application will be further described with reference to the accompanying drawings.

Specifically, the three-stage topology operation optimization method based on load importance according to the embodiment of the present application, as shown in fig. 1, includes:

s1, collecting operation data of the power distribution network after the fault, and establishing a topological structure for fault identification;

s2, establishing a load importance evaluation model according to the power loss electric charge in the distribution network operation data;

s3, searching a distributed power generation device with adjustable power in a distribution network island region, and performing one-stage topology optimization;

s4, establishing a two-stage topological optimization model, and carrying out load transfer on the spare feeder line and the distributed power generation device;

and S5, after the load transfer is carried out, if the target transformer substation in an overload operation state exists, establishing a secondary transfer model to obtain the optimal transfer load of the target transformer substation.

In implementation, when a substation full-stop accident occurs, a load transfer path can be optimized on the basis of considering load importance, the recovery rate of the power failure load is effectively improved on the basis of ensuring the system reliability, on one hand, the influence of the load importance on the optimization of a topological operation mode is considered in the scheme, and the feasibility of a topological optimization decision is further improved; on the other hand, a three-stage topological operation optimization strategy is provided, normal power supply load on the weak link is transferred to other transformer substations, the power supply recovery amount of the power failure area is increased, the provided topological operation optimization mode can effectively guarantee stable operation of the distribution network system, and the superiority of the topological optimization mode is further improved.

The implementation of the invention can effectively process the decision of the optimal operation mode of the distribution topology under the fault, improve the power supply reliability of the power distribution network, check and optimize the maintenance mode of the power distribution network, contribute to the comprehensive analysis of the load of the power distribution network of the regulation and control cloud platform and simultaneously contribute to the optimal utilization of the system capacity of the power distribution network; the method can provide lean planning tools and assessment tools for distribution network planning personnel of a power grid company, provides technical support for improving the reliability of the distribution network, reasonably assessing the supply and delivery capacity of the distribution network in a fault mode and improving the operation benefits of the distribution network, and has great economic and social benefits.

Optionally, the S1 includes:

collecting the number and positions of a transformer substation, a distribution transformer node, a connection feeder line, a breaker switch and a connection switch in a power distribution network;

constructing a topological structure according to the positions of the transformer substation, the distribution transformer node, the interconnection feeder line, the breaker switch and the interconnection switch, and adjusting the state of each device in the topological structure;

and determining the connection relation between the directly-connected transformer substation and the secondary connected transformer substation according to the adjusted topological structure.

In the implementation, taking an actual distribution network in a certain area as an example, as shown in fig. 2 after simplification, the distribution network is composed of 5 substations, 32 distribution nodes, 22 tie feeders, 3 distributed power generation devices (connected to distribution nodes 2, 9 and 11, respectively), 18 breaker switches and 14 tie switches. In order to simulate the actual load fluctuations, the distribution power uses the historical load curve of the distribution transformers in the urban network, assuming that the substation P is 12 pm₂SCSA takes place with a load L₁-L₈All power is lost, wherein switch S₅、S₉、S₁₂And S₁₄In a closed state and the remaining switches are in an open state.

Step a: and collecting the running state and running data of the distribution network after the fault, wherein the running state and running data comprise a grid structure, a topological running mode, the power loss load, the feeder line load rate, the transformer substation load rate and the like.

In this case, substation P₂The SCSA occurs, so the direct-connected substation and the secondary-connected substation under the SCSA can be determined according to the contact relationship between the substations in fig. 2, with the following results:

in the formula, P_dc-P2And P_sc-P2Respectively represent P₂And generating a direct-connected transformer substation and a corresponding secondary-connected transformer substation under the SCSA. Furthermore, in the power distribution network of FIG. 2 for recovering L₁-L₈The STP and MTP sets of (A) are as follows:

F_STP＝{F₍₁₎→F₍₂₎,F₍₃₎→F₍₃₀₎,F_(7,8)→F_(9,12),F₍₂₀₎→F₍₂₉₎,F_(15,19)}

F_MTP＝{{F₍₄₎→F_(31,32),F₍₄₎→F_(21,24)},{F_(5,6)→F₍₁₃₎,F_(5,6)→F₍₁₇₎}{F_(18,27)→F₍₂₂₎,F_(18,27)→F_(23,28)}}

in the formula, F_(i)Representing the line containing load i.

Optionally, the S2 includes:

fitting power failure loss functions of different types of loads by adopting a minimum bisection method, and calculating a weight coefficient of the load by using the power failure loss function according to the load type and the estimated power failure duration, wherein the calculation formula is as follows:

in the formula, ω_i,tRepresents the weight coefficient, alpha, of the load i at the time of power failure t_iAnd beta_iThe fitting parameters of the load power failure loss function are determined by the characteristics of the load.

In practice, the power outage loss functions for different types of loads are fitted using the least squares method based on the survey data, as shown in fig. 3. Therefore, the weight coefficient of the load can be calculated by using the power failure loss function according to the load type and the estimated power failure duration time, and the calculation formula is as follows:

in the formula, ω_i,tRepresents the weight coefficient, alpha, of the load i at the time of power failure t_iAnd beta_iThe fitting parameters for the load blackout loss functions are determined by the load characteristics, and the detailed parameters are shown in table 2.

TABLE 1 Power outage cost historical data (Unit: $/kW)

TABLE 2 fitting parameters for different types of loads

Optionally, the S3 includes:

for power-loss loads L1 and L2, no standby feeder is used for recovering power supply;

a distributed power plant with continuous power regulation capability operates in islanding mode to supply power to dead loads L1 and L2,

in implementation, a distributed power generation device with adjustable power in an isolated area is searched, and one-stage topology optimization is carried out. For power-off load L₁And L₂Distributed power generation device with continuous power regulation capability due to no spare feeder for recovering power supply₁The device can run under an island mode to lose power load L₁And L₂The results of the phase optimization with power supply are shown in table 3.

TABLE 3 first stage optimization results

Optionally, the S4 includes:

for the second-stage standby feeder line and the load of the distributed power generation device from grid connection to power loss, the power support of the grid-connected distributed power generation device is considered;

the load transfer result mainly comprises the recovery rate of the power-loss load, a transfer path and transfer time;

after the load transfer is completed, acquiring the load rate of the directly connected transformer substation;

and if the load rate is higher than a preset value, judging that the directly-connected transformer substation is in a dangerous operation state.

In the implementation, for the second-stage standby feeder and the load of the distributed power generation device from grid connection to power loss, grid connection and branch connection are considered simultaneouslyThe results of the power support and the two-stage load transfer of the distributed power generation device are shown in table 4. In table 4, the result of load transfer mainly includes the recovery rate of the power-loss load, the transfer path and the transfer time. However, under the transfer load L₅And L₆Rear, direct-connected substation P₁And P₄Is 0.92 and 1.0, respectively, beyond its maximum allowable load rate, will be in a hazardous operating state, so these two substations will be defined as HLRTS.

TABLE 4 second stage optimization results

Load at power cut	Type of load	Recovery rate	Supply time/min	Restoration path
					L3	Load of residents	78.8％	5	L3→S2→P1
L4	Load of residents	82.2％	16	L4→S3→S5→P1
					L5	Commercial load	100％	17	L5→S6→S9→P4
L6	Load of residents	67.6％	12	L6→S6→S9→P4
					L7	Industrial load	100％	6	L7→S7→P3
L8	Load of residents	83.8％	7	L8→S7→P3

Optionally, the S5 includes:

according to the third-stage transfer model, a secondary transfer strategy is adopted, namely, the third-stage optimization is carried out to solve the problem that the load rate of the directly-connected transformer substation is too high;

and updating the load rate of the directly-connected substation in the dangerous operation state according to the optimization result, and repeating the iteration of the second-stage and third-stage optimization until the directly-connected substation in the dangerous operation state disappears or cannot perform secondary transfer.

In implementation, the step is used for researching a three-stage topology optimization model on the basis of one-stage and two-stage topology optimization. According to the third-stage transfer model, a secondary transfer strategy is adopted, namely, third-stage optimization is carried out to solve the problem of overhigh load rate of the directly-connected transformer substation, and the third-stage optimization result is shown in table 5. After this stage, the load rate of the HLRTS is updated according to the optimization result, and iteration of the second-stage and third-stage optimization is performed again until the HLRTS disappears or secondary transfer cannot be performed, and the final load transfer scheme is shown in table 6.

TABLE 5 third stage optimization results

Power-off load	Action switch	Transfer path
			L29	S14	L29→S14→P5
L26	S11，S12	L26→S11→P5
			L27	S13	L27→S13→P5

TABLE 6 optimal load transfer results

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (6)

1. The three-stage topology operation optimization method based on load importance is characterized by comprising the following steps of:

s1, collecting operation data of the power distribution network after the fault, and establishing a topological structure for fault identification;

s2, establishing a load importance evaluation model according to the power loss electric charge in the distribution network operation data;

s3, searching a distributed power generation device with adjustable power in a distribution network island region, and performing one-stage topology optimization;

s4, establishing a two-stage topological optimization model, and carrying out load transfer on the spare feeder line and the distributed power generation device;

and S5, after the load transfer is carried out, if the target transformer substation in an overload operation state exists, establishing a secondary transfer model to obtain the optimal transfer load of the target transformer substation.

2. The three-stage topology operation optimization method based on load importance according to claim 1, wherein the S1 comprises:

collecting the number and positions of a transformer substation, a distribution transformer node, a connection feeder line, a breaker switch and a connection switch in a power distribution network;

constructing a topological structure according to the positions of the transformer substation, the distribution transformer node, the interconnection feeder line, the breaker switch and the interconnection switch, and adjusting the state of each device in the topological structure;

and determining the connection relation between the directly-connected transformer substation and the secondary connected transformer substation according to the adjusted topological structure.

3. The three-stage topology operation optimization method based on load importance according to claim 1, wherein the S2 comprises:

fitting power failure loss functions of different types of loads by adopting a minimum bisection method, and calculating a weight coefficient of the load by using the power failure loss function according to the load type and the estimated power failure duration, wherein the calculation formula is as follows:

in the formula, ω_i,tRepresents the weight coefficient, alpha, of the load i at the time of power failure t_iAnd beta_iThe fitting parameters of the load power failure loss function are determined by the characteristics of the load.

4. The three-stage topology operation optimization method based on load importance according to claim 1, wherein the S3 comprises:

for power-loss loads L1 and L2, no standby feeder is used for recovering power supply;

the distributed power generation device with continuous power regulation capability operates in an island mode to supply power to power loss loads L1 and L2.

5. The three-stage topology operation optimization method based on load importance according to claim 1, wherein the S4 comprises:

for the second-stage standby feeder line and the load of the distributed power generation device from grid connection to power loss, the power support of the grid-connected distributed power generation device is considered;

the load transfer result mainly comprises the recovery rate of the power-loss load, a transfer path and transfer time;

after the load transfer is completed, acquiring the load rate of the directly connected transformer substation;

and if the load rate is higher than a preset value, judging that the directly-connected transformer substation is in a dangerous operation state.

6. The three-stage topology operation optimization method based on load importance according to claim 1, wherein the S5 comprises:

according to the third-stage transfer model, a secondary transfer strategy is adopted, namely, the third-stage optimization is carried out to solve the problem that the load rate of the directly-connected transformer substation is too high;

and updating the load rate of the directly-connected substation in the dangerous operation state according to the optimization result, and repeating the iteration of the second-stage and third-stage optimization until the directly-connected substation in the dangerous operation state disappears or cannot perform secondary transfer.

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