CN117411003A - Reliability and vulnerability analysis method and system for power transmission system - Google Patents

Reliability and vulnerability analysis method and system for power transmission system Download PDF

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Publication number
CN117411003A
CN117411003A CN202311327316.7A CN202311327316A CN117411003A CN 117411003 A CN117411003 A CN 117411003A CN 202311327316 A CN202311327316 A CN 202311327316A CN 117411003 A CN117411003 A CN 117411003A
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China
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load
node
transmission system
power transmission
reliability
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Inventor
章德
谢宇峥
卢泓睿
李更丰
黄玉雄
谭祖贶
邹文秋
徐铭乾
杨琪铭
李明昊
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State Grid Corp of China SGCC
State Grid Hunan Electric Power Co Ltd
Economic and Technological Research Institute of State Grid Hunan Electric Power Co Ltd
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State Grid Corp of China SGCC
State Grid Hunan Electric Power Co Ltd
Economic and Technological Research Institute of State Grid Hunan Electric Power Co Ltd
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Priority to CN202311327316.7A priority Critical patent/CN117411003A/en
Publication of CN117411003A publication Critical patent/CN117411003A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/04—Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
    • H02J3/06—Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/14—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
    • H02J3/144—Demand-response operation of the power transmission or distribution network
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin

Abstract

The invention discloses a reliability and vulnerability analysis method of a power transmission system, which comprises the steps of obtaining data information of a target power transmission system; enumerating possible fault scenes of the target power transmission system and screening to obtain evaluation scenes; constructing a tide optimization model considering uncertainty of a new energy power generation system; solving a power flow optimization model under evaluation scenes to obtain optimal power flow data information of a target power transmission system under each evaluation scene; and calculating reliability analysis indexes and vulnerability analysis indexes of the target power transmission system, and completing reliability and vulnerability analysis of the target power transmission system. The invention also discloses a system for realizing the reliability and vulnerability analysis method of the power transmission system. The reliability and vulnerability analysis of the power transmission system can be realized, so that the overall safety and reliability of the power transmission system are improved, and the scheme is higher in reliability, better in accuracy and more objective and scientific.

Description

Reliability and vulnerability analysis method and system for power transmission system
Technical Field
The invention belongs to the field of electric automation, and particularly relates to a method and a system for analyzing reliability and vulnerability of a power transmission system.
Background
Along with the development of economic technology and the improvement of living standard of people, electric energy becomes an indispensable secondary energy source in the production and living of people, and brings endless convenience to the production and living of people. Therefore, ensuring stable and reliable supply of electric energy becomes one of the most important tasks of the electric power system.
Researchers have proposed various reliability and vulnerability analysis schemes for conventional power systems, such as a technical scheme for determining key buses of a power grid according to cascading failure behaviors of the power grid, a technical scheme for evaluating the reliability and vulnerability of the power system based on a probability method of an analysis technology, and the like. The scheme can finish the reliability and vulnerability assessment of the traditional power system according to the characteristics of the traditional power system, and can ensure enough reliability and accuracy.
However, as environmental problems become more serious, more and more new energy power generation systems are incorporated into the power grid and start generating power; this has led to the start of a transition from a conventional power system to a power system with a high proportion of new energy. After the high-proportion new energy power generation system is integrated into a power grid, the high randomness and high instability of the new energy power generation system lead the operation of the power system with the high-proportion new energy to face extremely high pressure; therefore, reliability and vulnerability analysis for power systems with a high proportion of new energy is very important.
However, when the reliability and vulnerability analysis scheme of the traditional power system is applied to the reliability and vulnerability analysis of the power system with high-proportion new energy, the reliability and accuracy of the analysis scheme are greatly reduced because the scheme does not consider the characteristics of the new energy power generation system and the grid change caused by the grid connection of the new energy power generation system, and the current evaluation requirement cannot be met.
Disclosure of Invention
The invention aims to provide a method for analyzing the reliability and the vulnerability of a power transmission system, which has high reliability, good accuracy and objectivity and science.
The second object of the invention is to provide a system for implementing the reliability and vulnerability analysis method of the power transmission system.
The method for analyzing the reliability and the vulnerability of the power transmission system provided by the invention comprises the following steps:
s1, acquiring data information of a target power transmission system;
s2, enumerating possible fault scenes of the target power transmission system according to the data information acquired in the step S1, and screening the enumerated fault scenes to acquire a plurality of evaluation scenes;
s3, constructing a tide optimization model considering uncertainty of the new energy power generation system by taking cut load minimization as a target according to the data information acquired in the step S1;
s4, solving the power flow optimization model constructed in the step S3 under the evaluation scenes obtained in the step S2 to obtain optimal power flow data information of the target power transmission system under each evaluation scene;
s5, calculating reliability analysis indexes and vulnerability analysis indexes of the target power transmission system according to the optimal power flow data information obtained in the step S4;
s6, according to the reliability analysis index and the vulnerability analysis index obtained in the step S5, the reliability and vulnerability analysis of the target power transmission system is completed.
The step S2 of enumerating possible fault scenes of the target power transmission system according to the data information acquired in the step S1, and screening the enumerated fault scenes to obtain a plurality of evaluation scenes, wherein the method specifically comprises the following steps:
enumerating possible fault scenes of the target power transmission system according to the data information acquired in the step S1, and calculating occurrence probability of the enumerated fault scenes according to the historical operation data and the fault data; the fault scene comprises an N-1 fault scene and an N-2 fault scene;
and reserving a fault scene with the occurrence probability larger than a set value as a final evaluation scene according to the obtained occurrence probability.
The step S3 of constructing a tide optimization model considering the uncertainty of the new energy power generation system according to the data information acquired in the step S1 with the aim of minimizing the cut load, specifically comprises the following steps:
the following formula is adopted as an objective function of the power flow optimization model:
in c i,jj The cut load quantity of the node i in the jj state is obtained; omega is state set of target power transmission systemCombining; n is a load node set of the target power transmission system;
the following formula is adopted as constraint conditions of the power flow optimization model:
the following formula is adopted for DC power flow modeling:
where i.fwdarw.j represents the flow from node i to node j; p (P) ij For active power flowing from node i to node j andθ i for the voltage phase angle of node i, θ j For the voltage phase angle of node j, x ij Is the reactance between node i and node j; />All active power generated for the power generation device at node j; k: j→k represents the flow from node j to node k; p (P) jk Is the active power flowing from node j to node k; />All active power consumed for the load at node j;
the following equation is used as a power loss constraint for the load node:
0≤P i L ≤P i LN
p in the formula i L All active power consumed for the load at node i; p (P) i LN Maximum load power at node i;
the following formula is adopted as the generating capacity constraint of the generating set node:
0≤P i G ≤P i GN
p in the formula i G All active power generated for the power generation device at node i; p (P) i GN Maximum output of the power generation device at the node iA power;
for the renewable energy node ii, the power generation amount of the power generation device of the renewable energy node is expressed by the following expression
In the middle ofMaximum output power of the power generation device at the renewable energy node ii; r is a random number and has a value of 0 to 1;
the following formula is adopted as the power generation capacity constraint of the semi-controllable renewable energy power generation device:
in the middle ofIs the controllable energy storage capacity at renewable energy node ii.
Under the evaluation scenario obtained in the step S2, the step S4 is implemented to solve the power flow optimization model constructed in the step S3, so as to obtain optimal power flow data information of the target power transmission system under each evaluation scenario, and specifically includes the following steps:
aiming at the evaluation scenes obtained in the step S2, solving the power flow optimization model constructed in the step S3 under each evaluation scene to obtain the optimal power flow data information of the target power transmission system under each evaluation scene;
the optimal power flow data information comprises the output of the power generation device, the load consumption power and the line load rate of the current evaluation scene.
And (5) calculating a reliability analysis index and a vulnerability analysis index of the target power transmission system according to the optimal power flow data information obtained in the step (S4), wherein the method specifically comprises the following steps of:
the reliability analysis indexes comprise load reliability analysis indexes and line reliability analysis indexes; the load reliability analysis index comprises a system average load shedding rate, a system load shedding expected, a load shedding rate of affected load nodes and a load shedding probability of the load nodes; the line reliability analysis indexes comprise line overload probability, average line overload degree and average overload rate of the overload line;
the average cut load ratio slalr of the system is calculated using the following equation:
in which L jj The load total amount of the target power transmission system in the jj state is calculated;
the system cut load expected SLOLE is calculated using the following equation:
in N Ω The total state number of the target power transmission system;
the affected load node cut load rate NLOLR is calculated using the following equation:
alpha in the formula i,jj As a binary variable of whether the load node i cuts the load in the jj-th state, if the load node i cuts the load in the jj-th state, alpha is calculated i,jj =1, otherwise α i,jj ＝0；l i,jj The load quantity of the load node i in the jj state is as follows;
the load node cut load probability NLOLP is calculated by adopting the following formula:
in N L Is the total number of load nodes;
the line reload probability LOP is calculated using the following equation:
o in k,jj If the line k of the target power transmission system is overloaded in the jj state, o k,jj =1, otherwise o k,jj =0; b is a line set of a target power transmission system; n (N) B The total number of lines of the target power transmission system;
the average line overload degree ALOD is calculated using the following equation:
in p k,jj The method comprises the steps of (1) setting a line load rate of a line k of a target power transmission system in a jj state; beta is a heavy duty rate set value;
calculating the average excess rate OLAOD of the heavy-load line as
The vulnerability analysis indexes comprise load vulnerability analysis indexes and line vulnerability analysis indexes; the load vulnerability analysis indexes comprise node average cut load quantity, node cut load probability and node average cut load ratio; the line vulnerability analysis indexes comprise line overload probability and line overload degree;
calculating the average cut load L of the node C,i Is that
Calculating node load shedding probability P C,i Is that
Calculating node average cut load ratio R C,i Is that
Calculating the line overload probability P O,k Is that
Calculating the line heavy load degree D O,k Is that
The invention also provides a system for realizing the reliability and vulnerability analysis method of the power transmission system, which comprises a data acquisition module, a scene screening module, a model construction module, a model solving module, an index calculation module and a comprehensive analysis module; the data acquisition module, the scene screening module, the model construction module, the model solving module, the index calculation module and the comprehensive analysis module are sequentially connected in series; the data acquisition module is used for acquiring data information of the target power transmission system and uploading the data to the scene screening module; the scene screening module is used for enumerating possible fault scenes of the target power transmission system according to the received data, screening the enumerated fault scenes to obtain a plurality of evaluation scenes, and uploading the data to the model construction module; the model construction module is used for constructing a tide optimization model considering the uncertainty of the new energy power generation system according to the received data with the cut load amount minimized as a target, and uploading the data to the model solving module; the model solving module is used for solving the constructed power flow optimization model under the obtained evaluation scenes according to the received data to obtain the optimal power flow data information of the target power transmission system under each evaluation scene, and uploading the data to the index calculating module; the index calculation module is used for calculating reliability analysis indexes and vulnerability analysis indexes of the target power transmission system according to the received data, and uploading the data to the comprehensive analysis module; and the comprehensive analysis module is used for completing the reliability and vulnerability analysis of the target power transmission system based on the reliability analysis index and the vulnerability analysis index according to the received data.
The reliability and vulnerability analysis method and system of the power transmission system provided by the invention are used for establishing a power transmission system reliability model considering the uncertainty of renewable energy sources, defining reliability analysis and vulnerability analysis indexes and applying the reliability and vulnerability analysis indexes to the reliability and vulnerability analysis of the power transmission system; therefore, the reliability and vulnerability analysis of the power transmission system can be realized, the overall safety and reliability of the power transmission system are improved, and the scheme is higher in reliability, better in accuracy and more objective and scientific.
Drawings
FIG. 1 is a schematic flow chart of the method of the present invention.
Fig. 2 is a schematic diagram of a node topology according to an embodiment of the method of the present invention.
FIG. 3 is a schematic diagram of functional modules of the system of the present invention.
Detailed Description
A schematic process flow diagram of the method of the present invention is shown in fig. 1: the method for analyzing the reliability and the vulnerability of the power transmission system provided by the invention comprises the following steps:
s1, acquiring data information of a target power transmission system;
s2, enumerating possible fault scenes of the target power transmission system according to the data information acquired in the step S1, and screening the enumerated fault scenes to acquire a plurality of evaluation scenes; the method specifically comprises the following steps:
enumerating possible fault scenes of the target power transmission system according to the data information acquired in the step S1, and calculating occurrence probability of the enumerated fault scenes according to the historical operation data and the fault data; the fault scene comprises an N-1 fault scene and an N-2 fault scene;
according to the obtained occurrence probability, reserving a fault scene with the occurrence probability larger than a set value as a final evaluation scene;
s3, constructing a tide optimization model considering uncertainty of the new energy power generation system by taking cut load minimization as a target according to the data information acquired in the step S1; the method specifically comprises the following steps:
the following formula is adopted as an objective function of the power flow optimization model:
in c i,jj The cut load quantity of the node i in the jj state is obtained; omega is a state set of a target power transmission system; n is a load node set of the target power transmission system;
the following formula is adopted as constraint conditions of the power flow optimization model:
the following formula is adopted for DC power flow modeling:
where i.fwdarw.j represents the flow from node i to node j; p (P) ij For active power flowing from node i to node j andθ i for the voltage phase angle of node i, θ j For the voltage phase angle of node j, x ij Is the reactance between node i and node j; />All active power generated for the power generation device at node j; k: j→k represents the flow from node j to node k; p (P) jk Is the active power flowing from node j to node k; />All active power consumed for the load at node j;
the following equation is used as a power loss constraint for the load node:
0≤P i L ≤P i LN
p in the formula i L All active power consumed for the load at node i; p (P) i LN Maximum load power at node i;
the following formula is adopted as the generating capacity constraint of the generating set node:
0≤P i G ≤P i GN
p in the formula i G All active power generated for the power generation device at node i; p (P) i GN Maximum output power of the power generation device at the node i;
for the renewable energy node ii, the power generation amount of the power generation device of the renewable energy node is expressed by the following expression
In the middle ofMaximum output power of the power generation device at the renewable energy node ii; r is a random number and has a value of 0 to 1;
the following formula is adopted as the power generation capacity constraint of the semi-controllable renewable energy power generation device:
in the middle ofControllable energy storage capacity at renewable energy node ii;
s4, solving the power flow optimization model constructed in the step S3 under the evaluation scenes obtained in the step S2 to obtain optimal power flow data information of the target power transmission system under each evaluation scene; the method specifically comprises the following steps:
aiming at the evaluation scenes obtained in the step S2, solving the power flow optimization model constructed in the step S3 under each evaluation scene to obtain the optimal power flow data information of the target power transmission system under each evaluation scene;
the optimal power flow data information comprises the output of the power generation device, the load consumption power and the line load rate of the current evaluation scene;
s5, calculating reliability analysis indexes and vulnerability analysis indexes of the target power transmission system according to the optimal power flow data information obtained in the step S4; the method specifically comprises the following steps:
the reliability analysis indexes comprise load reliability analysis indexes and line reliability analysis indexes; the load reliability analysis index comprises a system average load shedding rate, a system load shedding expected, a load shedding rate of affected load nodes and a load shedding probability of the load nodes; the line reliability analysis indexes comprise line overload probability, average line overload degree and average overload rate of the overload line;
the average cut load ratio slalr of the system is calculated using the following equation:
in which L jj The load total amount of the target power transmission system in the jj state is calculated;
the system cut load expected SLOLE is calculated using the following equation:
in N Ω The total state number of the target power transmission system;
the affected load node cut load rate NLOLR is calculated using the following equation:
alpha in the formula i,jj As a binary variable of whether the load node i cuts the load in the jj-th state, if the load node i cuts the load in the jj-th state, alpha is calculated i,jj =1, otherwise α i,jj ＝0；l i,jj The load quantity of the load node i in the jj state is as follows;
the load node cut load probability NLOLP is calculated by adopting the following formula:
in N L Is the total number of load nodes;
the line reload probability LOP is calculated using the following equation:
o in k,jj If the line k of the target power transmission system is overloaded in the jj state, o k,jj =1, otherwise o k,jj =0; b is a line set of a target power transmission system; n (N) B The total number of lines of the target power transmission system;
the average line overload degree ALOD is calculated using the following equation:
in p k,jj The method comprises the steps of (1) setting a line load rate of a line k of a target power transmission system in a jj state; beta is a heavy duty rate set value;
calculating the average excess rate OLAOD of the heavy-load line as
The vulnerability analysis indexes comprise load vulnerability analysis indexes and line vulnerability analysis indexes; the load vulnerability analysis indexes comprise node average cut load quantity, node cut load probability and node average cut load ratio; the line vulnerability analysis indexes comprise line overload probability and line overload degree;
calculating the average cut load L of the node C,i Is that
Calculating node load shedding probability P C,i Is that
Calculating node average cut load ratio R C,i Is that
Calculating the line overload probability P O,k Is that
Calculating the line heavy load degree D O,k Is that
S6, according to the reliability analysis index and the vulnerability analysis index obtained in the step S5, completing reliability and vulnerability analysis of the target power transmission system;
in the specific implementation, according to the obtained reliability analysis indexes (including the average system cut load rate, the system cut load expected, the affected load node cut load rate, the load node cut load probability, the line overload probability, the average line overload degree and the average overload line exceeding rate) and the vulnerability analysis indexes (including the average node cut load amount, the node cut load probability, the average node cut load rate, the line overload probability and the line overload degree), according to the data information of the target power transmission system, the specific analysis is carried out;
for example, for urban power transmission systems, the main objective is to guarantee a high reliability power supply for urban core areas, critical infrastructure (important government institutions, large hospitals, traffic signal systems, etc.). The reliability of the urban power transmission system can be evaluated according to the reliability analysis index, and the reliability of the system is further improved by adopting improvement and maintenance measures. For some power transmission systems in areas greatly affected by natural disasters, the vulnerability of the system should be analyzed, and the influence of system interruption on the areas is reduced by taking measures such as setting up a standby power supply, improving the disaster resistance of the system and the like for vulnerability index analysis.
The method of the invention is further described in connection with one embodiment as follows:
the topology of the target power transmission system is as shown in fig. 2: the system of fig. 2 includes 10 generators, 19 loads, 36 transmission lines and 12 transformers; in the embodiment, a standard IEEE 39 bus system is adopted, a renewable energy power generation unit is arranged at a 34 node, and the maximum power generation amount of the renewable energy power generation unit is equal to the average capacity of the remaining conventional generator set;
the system of fig. 2 sets three scenarios: scene 1: the power transmission system does not integrate a renewable energy power generation unit, namely the power output of the renewable energy power generation unit of the node 34 is 0; scene 2: the power transmission system is integrated with the uncontrollable renewable energy unit; scene 3: based on scenario 2, the uncertain renewable energy generating unit is modified into a unit comprising an energy storage system, the generator unit of the node 34 can adjust its output within a certain range, the controllable capacity range set in this embodiment is 50% of the maximum output power of the renewable energy unit,
performing reliability evaluation on the system of fig. 2, and simultaneously calculating a load reliability analysis index and a line reliability analysis index of the power transmission system; comparing reliability evaluation results of the system under different scenes; table 1 shows the results of the transmission system reliability assessment in scenario 1 and scenario 2:
table 1 schematic table of reliability evaluation results of power transmission system in scenario 1 and scenario 2
The load reliability index of the power transmission system can be seen that the load reliability of the system is obviously improved after the renewable energy generator set is integrated into the system, but the line reliability index of the system is not obviously changed. As renewable energy sources are incorporated into the grid, the power available to the system increases and the system load decreases significantly. However, when the line reliability index of the power transmission system is observed, the influence of the incorporation of the renewable energy sources on the line reliability of the power transmission system is small, and the incorporation of the renewable energy source unit does not change the existing topological structure of the transmission system; and thus does not significantly affect the line overload condition.
Vulnerability identification for the system of fig. 2: table 2 compares the cut load conditions of the systems under scenario 2 and scenario 3, starting from the load vulnerability identification:
table 2 load vulnerability index schematic table of power transmission system in scenario 2 and scenario 3
For some nodes that are not loaded, this embodiment is not discussed. In scenario 2, the severe congestion phenomenon of nodes 1, 9, 12, 18, 31 and 39 with load shedding conditions is significantly relieved in scenario 3. In scenario 2, when there is an uncertainty in the renewable energy unit output deficiency, the voltage at the node in table 2 is below the lower voltage limit, resulting in a significant load shedding. In scenario 3, the renewable energy system coordinates with the energy storage system, the output of the node is controlled within a fixed range, and the reliability of the system is improved by reducing the load shedding of the system. Meanwhile, the nodes serving as vulnerable points should be reinforced preferentially in power grid planning so as to effectively improve the reliability of the power transmission network. The distributed renewable energy power generation units are arranged at the nodes with relatively close topological distances, so that the reliability level of the transmission system can be effectively improved. As can be seen from table 2, installing distributed renewable energy sources at nodes with closer topological distances can effectively improve the reliability level of the power transmission system.
Table 3 compares and analyzes the line reliability indexes of the system in the scene 2 and the scene 3, ignores the non-overloaded line and considers the line with higher overload rate as the vulnerable line.
Table 3 transmission system line vulnerability index schematic table in scenario 2 and scenario 3
As can be seen from Table 3, the overload degree of the lines 12, 17 and 21 is high, the reliability index result of the power transmission system is seriously affected, and the power transmission system can be reinforced with emphasis in the subsequent work to improve the reliability of the power transmission system.
FIG. 3 is a schematic diagram of functional modules of the system of the present invention: the system for realizing the reliability and vulnerability analysis method of the power transmission system comprises a data acquisition module, a scene screening module, a model construction module, a model solving module, an index calculation module and a comprehensive analysis module; the data acquisition module, the scene screening module, the model construction module, the model solving module, the index calculation module and the comprehensive analysis module are sequentially connected in series; the data acquisition module is used for acquiring data information of the target power transmission system and uploading the data to the scene screening module; the scene screening module is used for enumerating possible fault scenes of the target power transmission system according to the received data, screening the enumerated fault scenes to obtain a plurality of evaluation scenes, and uploading the data to the model construction module; the model construction module is used for constructing a tide optimization model considering the uncertainty of the new energy power generation system according to the received data with the cut load amount minimized as a target, and uploading the data to the model solving module; the model solving module is used for solving the constructed power flow optimization model under the obtained evaluation scenes according to the received data to obtain the optimal power flow data information of the target power transmission system under each evaluation scene, and uploading the data to the index calculating module; the index calculation module is used for calculating reliability analysis indexes and vulnerability analysis indexes of the target power transmission system according to the received data, and uploading the data to the comprehensive analysis module; and the comprehensive analysis module is used for completing the reliability and vulnerability analysis of the target power transmission system based on the reliability analysis index and the vulnerability analysis index according to the received data.

Claims (6)

1. A method for analyzing reliability and vulnerability of a power transmission system comprises the following steps:
s1, acquiring data information of a target power transmission system;
s2, enumerating possible fault scenes of the target power transmission system according to the data information acquired in the step S1, and screening the enumerated fault scenes to acquire a plurality of evaluation scenes;
s3, constructing a tide optimization model considering uncertainty of the new energy power generation system by taking cut load minimization as a target according to the data information acquired in the step S1;
s4, solving the power flow optimization model constructed in the step S3 under the evaluation scenes obtained in the step S2 to obtain optimal power flow data information of the target power transmission system under each evaluation scene;
s5, calculating reliability analysis indexes and vulnerability analysis indexes of the target power transmission system according to the optimal power flow data information obtained in the step S4;
s6, according to the reliability analysis index and the vulnerability analysis index obtained in the step S5, the reliability and vulnerability analysis of the target power transmission system is completed.
2. The method for analyzing reliability and vulnerability of power transmission system according to claim 1, wherein the data information obtained in step S1 in step S2 enumerates possible fault scenes of the target power transmission system, and screens the enumerated fault scenes to obtain a plurality of evaluation scenes, and specifically comprises the following steps:
enumerating possible fault scenes of the target power transmission system according to the data information acquired in the step S1, and calculating occurrence probability of the enumerated fault scenes according to the historical operation data and the fault data; the fault scene comprises an N-1 fault scene and an N-2 fault scene;
and reserving a fault scene with the occurrence probability larger than a set value as a final evaluation scene according to the obtained occurrence probability.
3. The method for analyzing reliability and vulnerability of power transmission system according to claim 2, wherein the data information obtained in step S1 in step S3 is aimed at minimizing cut load, and the method specifically comprises the following steps:
the following formula is adopted as an objective function of the power flow optimization model:
in c i,jj The cut load quantity of the node i in the jj state is obtained; omega is a state set of a target power transmission system; n is a load node set of the target power transmission system;
the following formula is adopted as constraint conditions of the power flow optimization model:
the following formula is adopted for DC power flow modeling:
where i.fwdarw.j represents the flow from node i to node j; p (P) ij For active power flowing from node i to node j andθ i for the voltage phase angle of node i, θ j For the voltage phase angle of node j, x ij Is the reactance between node i and node j; />All active power generated for the power generation device at node j; k: j→k represents the flow from node j to node k; p (P) jk Is the active power flowing from node j to node k; />All active power consumed for the load at node j;
the following equation is used as a power loss constraint for the load node:
0≤P i L ≤P i LN
p in the formula i L All active power consumed for the load at node i; p (P) i LN Maximum load power at node i;
the following formula is adopted as the generating capacity constraint of the generating set node:
0≤P i G ≤P i GN
p in the formula i G All active power generated for the power generation device at node i; p (P) i GN Maximum output power of the power generation device at the node i;
for the renewable energy node ii, the power generation amount of the power generation device of the renewable energy node is expressed by the following expression
In the middle ofMaximum output power of the power generation device at the renewable energy node ii; r is a random number and has a value of 0 to 1;
the following formula is adopted as the power generation capacity constraint of the semi-controllable renewable energy power generation device:
in the middle ofIs the controllable energy storage capacity at renewable energy node ii.
4. The method for analyzing reliability and vulnerability of power transmission system according to claim 3, wherein in the evaluation scenario obtained in step S2, the method for analyzing the reliability and vulnerability of the power transmission system in step S4 is characterized by solving the power flow optimization model constructed in step S3 to obtain optimal power flow data information of the target power transmission system in each evaluation scenario, and specifically comprises the following steps:
aiming at the evaluation scenes obtained in the step S2, solving the power flow optimization model constructed in the step S3 under each evaluation scene to obtain the optimal power flow data information of the target power transmission system under each evaluation scene;
the optimal power flow data information comprises the output of the power generation device, the load consumption power and the line load rate of the current evaluation scene.
5. The method for analyzing reliability and vulnerability of power transmission system according to claim 4, wherein the step S5 is characterized in that the reliability analysis index and vulnerability analysis index of the target power transmission system are calculated according to the optimal power flow data information obtained in the step S4, and specifically comprises the following steps:
the reliability analysis indexes comprise load reliability analysis indexes and line reliability analysis indexes; the load reliability analysis index comprises a system average load shedding rate, a system load shedding expected, a load shedding rate of affected load nodes and a load shedding probability of the load nodes; the line reliability analysis indexes comprise line overload probability, average line overload degree and average overload rate of the overload line;
the average cut load ratio slalr of the system is calculated using the following equation:
in which L jj The load total amount of the target power transmission system in the jj state is calculated;
the system cut load expected SLOLE is calculated using the following equation:
in N Ω The total state number of the target power transmission system;
the affected load node cut load rate NLOLR is calculated using the following equation:
alpha in the formula i,jj As a binary variable of whether the load node i cuts the load in the jj-th state, if the load node i cuts the load in the jj-th state, alpha is calculated i,jj =1, otherwise α i,jj ＝0；l i,jj The load quantity of the load node i in the jj state is as follows;
the load node cut load probability NLOLP is calculated by adopting the following formula:
in N L Is the total number of load nodes;
the line reload probability LOP is calculated using the following equation:
o in k,jj If the line k of the target power transmission system is overloaded in the jj state, o k,jj =1, otherwise o k,jj =0; b is a line set of a target power transmission system; n (N) B Power transmission system for targetIs a total number of lines;
the average line overload degree ALOD is calculated using the following equation:
in p k,jj The method comprises the steps of (1) setting a line load rate of a line k of a target power transmission system in a jj state; beta is a heavy duty rate set value;
calculating the average excess rate OLAOD of the heavy-load line as
The vulnerability analysis indexes comprise load vulnerability analysis indexes and line vulnerability analysis indexes; the load vulnerability analysis indexes comprise node average cut load quantity, node cut load probability and node average cut load ratio; the line vulnerability analysis indexes comprise line overload probability and line overload degree;
calculating the average cut load L of the node C,i Is that
Calculating node load shedding probability P C,i Is that
Calculating node average cut load ratio R C,i Is that
Calculating the line overload probability P O,k Is that
Calculating the line heavy load degree D O,k Is that
6. A system for implementing the reliability and vulnerability analysis method of power transmission system according to any one of claims 1-5, characterized by comprising a data acquisition module, a scene screening module, a model construction module, a model solving module, an index calculation module and a comprehensive analysis module; the data acquisition module, the scene screening module, the model construction module, the model solving module, the index calculation module and the comprehensive analysis module are sequentially connected in series; the data acquisition module is used for acquiring data information of the target power transmission system and uploading the data to the scene screening module; the scene screening module is used for enumerating possible fault scenes of the target power transmission system according to the received data, screening the enumerated fault scenes to obtain a plurality of evaluation scenes, and uploading the data to the model construction module; the model construction module is used for constructing a tide optimization model considering the uncertainty of the new energy power generation system according to the received data with the cut load amount minimized as a target, and uploading the data to the model solving module; the model solving module is used for solving the constructed power flow optimization model under the obtained evaluation scenes according to the received data to obtain the optimal power flow data information of the target power transmission system under each evaluation scene, and uploading the data to the index calculating module; the index calculation module is used for calculating reliability analysis indexes and vulnerability analysis indexes of the target power transmission system according to the received data, and uploading the data to the comprehensive analysis module; and the comprehensive analysis module is used for completing the reliability and vulnerability analysis of the target power transmission system based on the reliability analysis index and the vulnerability analysis index according to the received data.
CN202311327316.7A 2023-10-13 2023-10-13 Reliability and vulnerability analysis method and system for power transmission system Pending CN117411003A (en)

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