A Distributed Coordinated Control Method and System for Power Flow in Transmission Lines Based on Energy Storage

Abstract

This invention discloses a distributed coordinated control method and system for power flow in transmission lines based on energy storage, comprising: determining a set of over-limit branches and a set of safety-constrained branches in the transmission network, and calculating the minimum power flow adjustment demand for each branch in the set of over-limit branches; determining a set of energy storage nodes, and determining the power flow control sensitivity of each energy storage node to each branch in the set of over-limit branches and the set of safety-constrained branches; calculating the comprehensive control sensitivity of each energy storage node to the power flow of each branch in the set of over-limit branches and the set of safety-constrained branches based on the power flow control sensitivity; obtaining the adjustable power of each energy storage node, and classifying the energy storage nodes according to the adjustable power and the comprehensive control sensitivity to determine a set of discharging nodes and a set of charging nodes; and adjusting the charging and discharging according to the minimum power flow adjustment demand, the set of discharging nodes, and the set of charging nodes to control the power of all branches in the transmission network to not exceed the limits.

Description

Technical Field

[0001] This invention relates to the field of application technology of large-scale energy storage in the safe and stable control of power systems, and more specifically, to a method and system for distributed coordinated control of power flow in transmission lines based on energy storage. Background Technology

[0002] With the large-scale integration of new energy sources and high-capacity DC transmission, the short-term obstruction of transmission channels in areas rich in new energy sources and the short-term overload of lines or transformers caused by power flow transfer after AC or DC faults in the receiving-end power grid fed by high-capacity DC transmission have become important factors restricting the development of new energy sources and limiting AC and DC transmission capacity.

[0003] Current planning and operational measures typically include constructing new transmission and transformation equipment, limiting the maximum capacity of renewable energy sources, and pre-controlling the transmission power of DC power. These measures, on the one hand, restrict the scale of renewable energy development or reduce the utilization rate of grid facilities; on the other hand, they place higher demands on the adjustment of operation modes after faults. In the context of building a new power system dominated by renewable energy, energy storage devices with rapid power throughput capabilities will be widely integrated, providing a potential means of power flow control for the power system. Effectively controlling the large number of distributed energy storage devices in the system can solve problems such as obstruction at transmission lines in areas with concentrated renewable energy transmission or short-term overload of local sections after faults.

[0004] Therefore, a distributed coordinated control method for power flow in transmission lines based on energy storage is needed. Summary of the Invention

[0005] This invention proposes a distributed coordinated control method and system for power flow in transmission lines based on energy storage, in order to solve the problem of how to achieve multi-point coordinated control of power flow in transmission lines based on large-scale energy storage.

[0006] To address the aforementioned problems, according to one aspect of the present invention, a distributed coordinated control method for power flow in transmission lines based on energy storage is provided, the method comprising:

[0007] Determine the set of over-limit branches and the set of safety-constrained branches in the transmission network, and calculate the minimum power flow adjustment requirement for each branch in the set of over-limit branches;

[0008] Determine the set of energy storage nodes, and determine the power flow control sensitivity of each energy storage node in the set of energy storage nodes to each branch in the set of over-limit branches and the set of safety-constrained branches;

[0009] Based on the power flow control sensitivity, calculate the comprehensive control sensitivity of each energy storage node in the energy storage node set for each power flow in the set of over-limit branches and the set of safety-constrained branches;

[0010] The adjustable power of each energy storage node is obtained, and the energy storage nodes are classified according to the adjustable power and the comprehensive control sensitivity to determine the set of discharge nodes and the set of charging nodes.

[0011] The charging and discharging are adjusted according to the minimum power flow adjustment demand, the set of discharge nodes, and the set of charging nodes to control the power of all branches in the transmission network to not exceed the limit.

[0012] Preferably, the method calculates the minimum power flow adjustment requirement for each branch in the set of over-limit branches in the following manner:

[0013]

[0014] Wherein, ΔP T min,i P represents the minimum power flow adjustment demand for the i-th branch in the set of over-limit branches A; L max,i Let be the transmission power limit value of the i-th branch in the set of over-limit branches A; is the initial power flow value for the i-th branch; n is the number of branches that exceed the limit.

[0015] Preferably, the set of safety constraint branches includes: branches with a load rate greater than or equal to a first preset safety threshold μ1 and all other branches in the critical section where the over-limit branches are located;

[0016] The load factor is determined using the following methods:

[0017]

[0018] Where, β L,j Let P be the load rate of the j-th branch; L max,j Let be the transmission power limit of the j-th branch; Let μ be the initial power flow value of the j-th branch; μ1 is the first preset safety threshold, satisfying 0 < μ1 < 1.

[0019] Preferably, determining the power flow control sensitivity of each energy storage node in the set of energy storage nodes to each branch in the set of over-limit branches and the set of safety-constrained branches includes:

[0020]

[0021] Among them, S pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; let be the change in energy storage power of the k-th energy storage node be ΔP. S,k The power reduction of the p-th branch is ΔP. L,p Among them, S pk≥0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node discharges; conversely, S pk <0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node is charging; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes.

[0022] Preferably, the step of calculating the comprehensive control sensitivity of each energy storage node in the energy storage node set to the power flow of each branch in the set of over-limit branches and the set of safety-constrained branches, based on the power flow control sensitivity, includes:

[0023]

[0024]

[0025]

[0026] Among them, f S,k The overall control sensitivity of the k-th energy storage node; α L,p β is the weight coefficient of the p-th branch; L,p Let P be the load factor of the p-th branch; L max,p Let be the transmission power limit value of the p-th branch; S represents the initial power flow value for the p-th branch; pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes; μ2 is the second preset safety threshold, satisfying 0 < μ2 ≤ μ1.

[0027] Preferably, the process of classifying energy storage nodes according to the adjustable power and comprehensive control sensitivity to determine the set of discharge nodes and the set of charging nodes includes:

[0028] Based on the adjustable power and comprehensive control sensitivity, the energy storage nodes are classified into types to determine the discharge energy storage nodes and the charging energy storage nodes. The discharge energy storage nodes and the charging energy storage nodes are then sorted in descending order according to the absolute value of the comprehensive control sensitivity to determine the discharge node set and the charging node set.

[0029] Wherein, if the comprehensive control sensitivity of the k-th energy storage node satisfies f S,k >0, and the maximum available discharge power satisfies P F max,k If σ > 0, then the kth energy storage node is determined as the discharge node; if the comprehensive control sensitivity of the kth energy storage node satisfies f S,k <0, and the maximum available discharge power satisfies P C max,k If σ > 0, then the kth energy storage node is determined as the charging node;

[0030] Among them, fS,k P represents the overall control sensitivity of the k-th energy storage node. F max,k and P C max,k σ represents the maximum available discharge power and the maximum available charging power of the k-th energy storage node, respectively; σ is the preset adjustable power threshold.

[0031] Preferably, the adjustment of charging and discharging based on the minimum power flow adjustment demand, the set of discharging nodes, and the set of charging nodes to control the power of all branches in the transmission network to not exceed the limit includes:

[0032] S51, Initialize K=1, P=1,

[0033] S52, calculate the minimum energy storage adjustment power ΔP required for each branch in the set of over-limit branches A based on the minimum power flow adjustment demand. i ;

[0034] S53, select the Kth discharge energy storage node and the Pth charging energy storage node in the discharge sequence C1 and charging sequence C2 respectively, and obtain the maximum available discharge power P of the Kth discharge energy storage node. F max,K and the maximum available charging power P of the Pth charging energy storage node C max,P ;

[0035] S54, determine the minimum energy storage adjustment power ΔP required for each branch. i The maximum value in Max(ΔP) i Does it simultaneously satisfy Max(ΔP)? i )≤P F max,K and Max(ΔP) i )≤P C max,P If satisfied, it is determined that the power flow of each branch can be controlled within the power limit through this round of adjustment, based on the fact that the required discharge power and charging power of energy storage node K and energy storage node P are both Max(ΔP). i ) Perform charge and discharge adjustments to control the power of all branches in the transmission network to ensure that it does not exceed the limit; otherwise, if P F max,K <P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. F max,K Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k And the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update K = K + 1, and return to S52 to recalculate; if P F max,K >P C max,PThen let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. C max,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k and the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update P = P + 1, and return to S52 to recalculate; if P F max,K =P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. F max,K and P C max,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k and the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update K = K+1, P = P+1, and return to S52 to recalculate; until the minimum energy storage adjustment power ΔP required for each branch is reached. i The maximum value in Max(ΔP) i Simultaneously satisfying Max(ΔP) i )≤P F max,K and Max(ΔP) i )≤P C max,P At that time, the required discharge power and charging power for the current energy storage node K and energy storage node P are both the current Max(ΔP). i The power supply is adjusted by charging and discharging to ensure that the power of all branches in the power transmission network does not exceed the limit.

[0036] Preferably, the method determines the minimum energy storage adjustment power ΔP using the following method. i ,include:

[0037]

[0038] Wherein, ΔP i S is the minimum energy storage adjustment power required for the i-th branch in the set of over-limit branches A; iK and S iP ΔP represents the power flow control sensitivity of the Kth discharge energy storage node and the Pth charge energy storage node to the i-th branch, respectively; T min,i Let i be the minimum power flow adjustment demand for the i-th branch.

[0039] According to another aspect of the present invention, a power flow distributed coordination control system based on energy storage for transmission lines is provided, the system comprising:

[0040] The minimum power flow adjustment demand determination unit is used to determine the set of over-limit branches and the set of safety-constrained branches in the transmission network, and to calculate the minimum power flow adjustment demand for each branch in the set of over-limit branches.

[0041] A power flow control sensitivity determination unit is used to determine the set of energy storage nodes and to determine the power flow control sensitivity of each energy storage node in the set of energy storage nodes to each branch in the set of over-limit branches and the set of safety-constrained branches.

[0042] The integrated control sensitivity determination unit is used to calculate the integrated control sensitivity of each energy storage node in the energy storage node set to the power flow of each branch in the set of over-limit branches and the set of safety-constrained branches, based on the power flow control sensitivity.

[0043] The node classification unit is used to obtain the adjustable power of each energy storage node, and classify the energy storage nodes according to the adjustable power and the comprehensive control sensitivity to determine the set of discharge nodes and the set of charging nodes.

[0044] The control unit is used to adjust the charging and discharging according to the minimum power flow adjustment demand, the set of discharge nodes and the set of charging nodes, so as to control the power of all branches in the transmission network to not exceed the limit.

[0045] Preferably, the minimum power flow adjustment demand determination unit calculates the minimum power flow adjustment demand for each branch in the set of over-limit branches using the following method:

[0046]

[0047] Wherein, ΔP T min,i P represents the minimum power flow adjustment demand for the i-th branch in the set of over-limit branches A; L max,i Let be the transmission power limit value of the i-th branch in the set of over-limit branches A; is the initial power flow value for the i-th branch; n is the number of branches that exceed the limit.

[0048] Preferably, in the minimum power flow adjustment demand determination unit, the set of safety constraint branches includes: branches with a load rate greater than or equal to a first preset safety threshold μ1 and all other branches in the critical section where the over-limit branches are located;

[0049] The load factor is determined using the following methods:

[0050]

[0051] Where, β L,j Let P be the load rate of the j-th branch; L max,jLet be the transmission power limit of the j-th branch; Let μ be the initial power flow value of the j-th branch; μ1 is the first preset safety threshold, satisfying 0 < μ1 < 1.

[0052] Preferably, the power flow control sensitivity determination unit determines the power flow control sensitivity of each energy storage node in the energy storage node set to each branch in the set of over-limit branches and the set of safety-constrained branches, including:

[0053]

[0054] Among them, S pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; let be the change in energy storage power of the k-th energy storage node be ΔP. S,k The power reduction of the p-th branch is ΔP. L,p Among them, S pk ≥0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node discharges; conversely, S pk <0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node is charging; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes.

[0055] Preferably, the integrated control sensitivity determination unit calculates the integrated control sensitivity of each energy storage node in the energy storage node set to the power flow of each branch in the set of over-limit branches and the set of safety-constrained branches, based on the power flow control sensitivity, including:

[0056]

[0057]

[0058]

[0059] Among them, f S,k The overall control sensitivity of the k-th energy storage node; α L,p β is the weight coefficient of the p-th branch; L,p Let P be the load factor of the p-th branch; L max,p Let be the transmission power limit value of the p-th branch; S represents the initial power flow value for the p-th branch; pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes; μ2 is the second preset safety threshold, satisfying 0 < μ2 ≤ μ1.

[0060] Preferably, the node classification unit categorizes energy storage nodes based on the adjustable power and comprehensive control sensitivity, determining the discharge node set and the charging node set, including:

[0061] Based on the adjustable power and comprehensive control sensitivity, the energy storage nodes are classified into types to determine the discharge energy storage nodes and the charging energy storage nodes. The discharge energy storage nodes and the charging energy storage nodes are then sorted in descending order according to the absolute value of the comprehensive control sensitivity to determine the discharge node set and the charging node set.

[0062] Wherein, if the comprehensive control sensitivity of the k-th energy storage node satisfies f S,k >0, and the maximum available discharge power satisfies P F max,k If σ > 0, then the kth energy storage node is determined as the discharge node; if the comprehensive control sensitivity of the kth energy storage node satisfies f S,k <0, and the maximum available discharge power satisfies P C max,k If σ > 0, then the kth energy storage node is determined as the charging node;

[0063] Among them, f S,k P represents the overall control sensitivity of the k-th energy storage node. F max,k and P C max,k σ represents the maximum available discharge power and the maximum available charging power of the k-th energy storage node, respectively; σ is the preset adjustable power threshold.

[0064] Preferably, the control unit adjusts the charging and discharging based on the minimum power flow adjustment demand, the set of discharging nodes, and the set of charging nodes to control the power of all branches in the transmission network to not exceed the limit, including:

[0065] S51, Initialize K=1, P=1,

[0066] S52, calculate the minimum energy storage adjustment power ΔP required for each branch in the set of over-limit branches A based on the minimum power flow adjustment demand. i ;

[0067] S53, select the Kth discharge energy storage node and the Pth charging energy storage node in the discharge sequence C1 and charging sequence C2 respectively, and obtain the maximum available discharge power P of the Kth discharge energy storage node. F max,K and the maximum available charging power P of the Pth charging energy storage node C max,P ;

[0068] S54, determine the minimum energy storage adjustment power ΔP required for each branch. i The maximum value in Max(ΔP) i Does it simultaneously satisfy Max(ΔP)? i )≤P F max,K and Max(ΔP)i )≤P C max,P If satisfied, it is determined that the power flow of each branch can be controlled within the power limit through this round of adjustment, based on the fact that the required discharge power and charging power of energy storage node K and energy storage node P are both Max(ΔP). i ) Perform charge and discharge adjustments to control the power of all branches in the transmission network to ensure that it does not exceed the limit; otherwise, if P F max,K <P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. F max,K Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k And the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update K = K + 1, and return to S52 to recalculate; if P F max,K >P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. C max,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k and the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update P = P + 1, and return to S52 to recalculate; if P F max,K =P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. F max,K and P C max,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k and the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update K = K+1, P = P+1, and return to S52 to recalculate; until the minimum energy storage adjustment power ΔP required for each branch is reached. i The maximum value in Max(ΔP) i Simultaneously satisfying Max(ΔP) i )≤P F max,K and Max(ΔP) i )≤P C max,P At that time, the required discharge power and charging power for the current energy storage node K and energy storage node P are both the current Max(ΔP).i The power supply is adjusted by charging and discharging to ensure that the power of all branches in the power transmission network does not exceed the limit.

[0069] Preferably, the control unit determines the minimum energy storage adjustment power ΔP using the following method. i ,include:

[0070]

[0071] Wherein, ΔP i S is the minimum energy storage adjustment power required for the i-th branch in the set of over-limit branches A; iK and S iP ΔP represents the power flow control sensitivity of the Kth discharge energy storage node and the Pth charge energy storage node to the i-th branch, respectively; T min,i Let i be the minimum power flow adjustment demand for the i-th branch.

[0072] This invention provides a distributed coordinated control method and system for power flow in transmission lines based on energy storage. It calculates the power flow control sensitivity of each energy storage node in the transmission line to branches within the overload branch set and the safety constraint set, and calculates the comprehensive power flow control sensitivity of each energy storage node based on the power flow control sensitivity. The adjustable power of each energy storage node is obtained, and the energy storage nodes are classified according to the adjustable power and comprehensive control sensitivity to determine the discharge node set and the charging node set. The charging and discharging are adjusted according to the minimum power flow adjustment demand, the discharge node set, and the charging node set to control the power of all branches in the transmission network to ensure that the power does not exceed the limit. This method utilizes the rapid power response characteristics of energy storage to provide a flexible and rapid power regulation means to solve problems such as short-term overload of local sections after blockage or faults in areas with concentrated new energy transmission. It can not only reduce power grid construction investment and improve the utilization rate of power grid facilities, but also buy more time for adjusting the operation mode after a power grid accident. At the same time, by introducing a set of safety constraint branches and comprehensive control sensitivity, the method of this invention can quickly determine the adjustment direction of energy storage, and can reduce the power flow of overloaded lines without creating new overloaded lines. This invention can be used for online calculation and offline analysis, and can provide technical support for power grid planning and operation analysis personnel. Attached Figure Description

[0073] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0074] Figure 1 This is a flowchart of a power flow distributed coordination control method 100 for transmission lines based on energy storage according to an embodiment of the present invention.

[0075] Figure 2This is a schematic diagram of an IEEE 39-node system according to an embodiment of the present invention;

[0076] Figure 3 This is a schematic diagram of the structure of a power flow distributed coordination control system 300 for transmission lines based on energy storage according to an embodiment of the present invention. Detailed Implementation

[0077] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0078] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0079] Figure 1 This is a flowchart of a power flow distributed coordination control method 100 for transmission lines based on energy storage, according to an embodiment of the present invention. Figure 1 As shown, the energy storage-based distributed power flow coordination control method for transmission lines provided by this invention utilizes the rapid power response characteristics of energy storage to provide a flexible and rapid power regulation means to solve problems such as short-term overload of local sections after blockage or faults in areas with concentrated new energy transmission. It achieves adjustment of power flow in overloaded branches of the power grid, enriches the means of system power flow regulation, improves the utilization efficiency of power grid facilities, and buys more time for adjusting the operation mode after an accident. Simultaneously, by introducing a set of safety-constrained branches and comprehensive control sensitivity, this invention can quickly determine the adjustment direction of energy storage and reduce power flow in overloaded lines without creating new overloaded lines. This invention can be used for online calculation and offline analysis, providing technical support for power grid planning and operation analysis personnel. The energy storage-based distributed power flow coordination control method 100 provided by this invention begins at step 101, where the set of overloaded branches and the set of safety-constrained branches in the transmission network are determined, and the minimum power flow adjustment requirement for each branch in the set of overloaded branches is calculated.

[0080] Preferably, the method calculates the minimum power flow adjustment requirement for each branch in the set of over-limit branches in the following manner:

[0081]

[0082] Wherein, ΔP T min,i P represents the minimum power flow adjustment demand for the i-th branch in the set of over-limit branches A; L max,i Let be the transmission power limit value of the i-th branch in the set of over-limit branches A; is the initial power flow value for the i-th branch; n is the number of branches that exceed the limit.

[0083] Preferably, the set of safety constraint branches includes: branches with a load rate greater than or equal to a first preset safety threshold μ1 and all other branches in the critical section where the over-limit branches are located;

[0084] The load factor is determined using the following methods:

[0085]

[0086] Where, β L,j Let P be the load rate of the j-th branch; L max,j Let be the transmission power limit of the j-th branch; Let μ be the initial power flow value of the j-th branch; μ1 is the first preset safety threshold, satisfying 0 < μ1 < 1.

[0087] In an embodiment of the present invention, it is first necessary to determine the set of over-limit branches and the set of safety-constrained branches in the transmission network, and then calculate the minimum power flow adjustment requirement for each branch in the set of over-limit branches.

[0088] Specifically, the set of overloaded branches A is determined based on the network power flow calculation results, and the minimum power flow adjustment requirement for each branch in the set is calculated according to equation (1), including:

[0089]

[0090] Where A is the set of all overloaded branches in the transmission network under study, n is the number of overloaded branches, and P L max,i Let i be the transmission power limit of the i-th branch in set A. Let ΔP be the initial power flow value for the i-th branch. T min,i Let be the minimum power flow adjustment amount for the i-th branch.

[0091] In the embodiments of the present invention, the set of safety-constrained branches in the power transmission network to be studied includes two parts: one is all other branches in the critical section where the over-limit branch is located, and the other is the branch whose load rate exceeds the first preset safety threshold μ1 (0<μ1<1) as shown in equation (2).

[0092] The load factor is determined using the following methods:

[0093]

[0094] Where, β L,j Let P be the load rate of the j-th branch; L max,j Let be the transmission power limit of the j-th branch; Let be the initial power flow value for the j-th branch.

[0095] In step 102, the set of energy storage nodes is determined, and the power flow control sensitivity of each energy storage node in the set of energy storage nodes to each branch in the set of over-limit branches and the set of safety-constrained branches is determined.

[0096] Preferably, determining the power flow control sensitivity of each energy storage node in the set of energy storage nodes to each branch in the set of over-limit branches and the set of safety-constrained branches includes:

[0097]

[0098] Among them, S pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; let be the change in energy storage power of the k-th energy storage node be ΔP. S,k The power reduction of the p-th branch is ΔP. L,p Among them, S pk ≥0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node discharges; conversely, S pk <0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node is charging; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes.

[0099] In an embodiment of the present invention, the set of energy storage nodes comprising controllable energy storage is defined as C, and the adjustable power P of each node in C is read. F max,k and P C max,k Among them, P F max,k and P C max,k Let C be the maximum available discharge power and the maximum available charging power of the k-th node. Calculate the power flow control sensitivity of each energy storage node in C to each branch in sets A and B.

[0100] Wherein, if the change in energy storage power obtained by any k-th energy storage node is ΔP S,k The power reduction of the p-th branch is ΔP. L,p Then the power flow control sensitivity of the k-th energy storage node to the p-th branch is:

[0101]

[0102] Among them, S pk >0 indicates that the power flow of the p-th branch decreases when the energy storage at node k discharges; conversely, Spk <0 indicates that the power flow of the p-th branch decreases when the energy storage of node k is charged.

[0103] In step 103, based on the power flow control sensitivity, the comprehensive control sensitivity of each energy storage node in the energy storage node set to the power flow of each branch in the over-limit branch set and the safety-constrained branch set is calculated.

[0104] Preferably, the step of calculating the comprehensive control sensitivity of each energy storage node in the energy storage node set to the power flow of each branch in the set of over-limit branches and the set of safety-constrained branches, based on the power flow control sensitivity, includes:

[0105]

[0106]

[0107]

[0108] Among them, f S,k The overall control sensitivity of the k-th energy storage node; α L,p β is the weight coefficient of the p-th branch; L,p Let P be the load factor of the p-th branch; L max,p Let be the transmission power limit value of the p-th branch; S represents the initial power flow value for the p-th branch; pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes; μ2 is the second preset safety threshold, satisfying 0 < μ2 ≤ μ1.

[0109] In an embodiment of the present invention, the comprehensive control sensitivity of each energy storage node is calculated. Specifically, a second preset safety threshold μ2 (0 < μ2 ≤ μ1) is set, and the comprehensive control sensitivity f of each node in C to the power flow of each branch in set A and set B is calculated according to equation (4). S,k Among them, the weight coefficient α of each branch in set A and set B is calculated according to equation (5). L,p The load rate of each branch is calculated according to formula (6); the calculation formula is as follows:

[0110]

[0111]

[0112]

[0113] Among them, f S,k The overall control sensitivity of the k-th energy storage node; α L,p β is the weight coefficient of the p-th branch;L,p Let P be the load factor of the p-th branch; L max,p Let be the transmission power limit value of the p-th branch; S represents the initial power flow value for the p-th branch; pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch.

[0114] In step 104, the adjustable power of each energy storage node is obtained, and the energy storage nodes are classified according to the adjustable power and the comprehensive control sensitivity to determine the set of discharge nodes and the set of charging nodes.

[0115] Preferably, the process of classifying energy storage nodes according to the adjustable power and comprehensive control sensitivity to determine the set of discharge nodes and the set of charging nodes includes:

[0116] Based on the adjustable power and comprehensive control sensitivity, the energy storage nodes are classified into types to determine the discharge energy storage nodes and the charging energy storage nodes. The discharge energy storage nodes and the charging energy storage nodes are then sorted in descending order according to the absolute value of the comprehensive control sensitivity to determine the discharge node set and the charging node set.

[0117] Wherein, if the comprehensive control sensitivity of the k-th energy storage node satisfies f S,k >0, and the maximum available discharge power satisfies P F max,k If σ > 0, then the kth energy storage node is determined as the discharge node; if the comprehensive control sensitivity of the kth energy storage node satisfies f S,k <0, and the maximum available discharge power satisfies P C max,k If σ > 0, then the kth energy storage node is determined as the charging node;

[0118] Among them, f S,k P represents the overall control sensitivity of the k-th energy storage node. F max,k and P C max,k σ represents the maximum available discharge power and the maximum available charging power of the k-th energy storage node, respectively; σ is the preset adjustable power threshold.

[0119] In an embodiment of the present invention, after determining the comprehensive control sensitivity, the adjustable power of each energy storage node is obtained, and the energy storage nodes are classified according to the adjustable power and the comprehensive control sensitivity. The order of the energy storage nodes is adjusted according to the magnitude of the comprehensive sensitivity, thereby determining the set of discharge nodes and the set of charge nodes.

[0120] Specifically, based on comprehensive sensitivity and adjustable power, the energy storage nodes are divided into a discharge node set C1 and a charging node set C2, and an adjustable power threshold σ is set. If f S,k >0 and P F max,k If f > σ, then the k-th energy storage node is a discharge node, i.e., k∈C1; conversely, if fS,k <0, and P C max,k If σ > 0, then the k-th energy storage node is a charging node, i.e., k ∈ C2. Then, the nodes in C1 and C2 are arranged according to |f... S,k Sort the values ​​of |f in descending order. S,k The largest node is the priority control node and becomes an element in the corresponding node set.

[0121] In step 105, the charging and discharging are adjusted according to the minimum power flow adjustment demand, the set of discharge nodes, and the set of charging nodes to control the power of all branches in the transmission network to not exceed the limit.

[0122] Preferably, the adjustment of charging and discharging based on the minimum power flow adjustment demand, the set of discharging nodes, and the set of charging nodes to control the power of all branches in the transmission network to not exceed the limit includes:

[0123] S51, Initialize K=1, P=1,

[0124] S52, calculate the minimum energy storage adjustment power ΔP required for each branch in the set of over-limit branches A based on the minimum power flow adjustment demand. i ;

[0125] S53, select the Kth discharge energy storage node and the Pth charging energy storage node in the discharge sequence C1 and charging sequence C2 respectively, and obtain the maximum available discharge power P of the Kth discharge energy storage node. F max,K and the maximum available charging power P of the Pth charging energy storage node C max,P ;

[0126] S54, determine the minimum energy storage adjustment power ΔP required for each branch. i The maximum value in Max(ΔP) i Does it simultaneously satisfy Max(ΔP)? i )≤P F max,K and Max(ΔP) i )≤P C max,P If satisfied, it is determined that the power flow of each branch can be controlled within the power limit through this round of adjustment, based on the fact that the required discharge power and charging power of energy storage node K and energy storage node P are both Max(ΔP). i ) Perform charge and discharge adjustments to control the power of all branches in the transmission network to ensure that it does not exceed the limit; otherwise, if P F max,K <P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. F max,K Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,kAnd the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update K = K + 1, and return to S52 to recalculate; if P F max,K >P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. C max,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k and the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update P = P + 1, and return to S52 to recalculate; if P F max,K =P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. F max,K and P C max,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k and the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update K = K+1, P = P+1, and return to S52 to recalculate; until the minimum energy storage adjustment power ΔP required for each branch is reached. i The maximum value in Max(ΔP) i Simultaneously satisfying Max(ΔP) i )≤P F max,K and Max(ΔP) i )≤P C max,P At that time, the required discharge power and charging power for the current energy storage node K and energy storage node P are both the current Max(ΔP). i The power supply is adjusted by charging and discharging to ensure that the power of all branches in the power transmission network does not exceed the limit.

[0127] Preferably, the method determines the minimum energy storage adjustment power ΔP using the following method. i ,include:

[0128]

[0129] Wherein, ΔP i S is the minimum energy storage adjustment power required for the i-th branch in the set of over-limit branches A; iK and S iPΔP represents the power flow control sensitivity of the Kth discharge energy storage node and the Pth charge energy storage node to the i-th branch, respectively; T min,i Let i be the minimum power flow adjustment demand for the i-th branch.

[0130] In an embodiment of the present invention, based on the principle of minimizing unbalanced power (which can minimize the adjustment of other power generation equipment in the system), pairing control is performed in the discharge node set C1 and the charging node set C2 according to a determined control priority order, thereby controlling the power of all branches in the transmission network to not exceed the limit.

[0131] Specifically, this includes: initializing K=1 and P=1, selecting the Kth discharge energy storage node and the Pth charge energy storage node in the discharge sequence C1 and the charge sequence C2 respectively, and obtaining the maximum available discharge power P of energy storage node K. F max,K And the maximum available charging power P of the energy storage node P C max,P ; Calculate the minimum energy storage adjustment power ΔP required for each branch in the set of over-limit branches A. i It satisfies equation (7):

[0132]

[0133] Wherein, ΔP i S is the minimum energy storage adjustment power required for the i-th branch in the set of over-limit branches A; iK and S iP ΔP represents the power flow control sensitivity of the Kth discharge energy storage node and the Pth charge energy storage node to the i-th branch, respectively; T min,i Let i be the minimum power flow adjustment demand for the i-th branch.

[0134] If the minimum energy storage adjustment power required by each branch is Max(ΔP) i The available adjustable power less than that of nodes K and P, i.e., Max(ΔP) i )≤P F max,K And Max(ΔP) i )≤P C max,P This indicates that the power flow of each branch can be controlled within the power limit through this round of adjustment. Energy storage nodes K and P are adjusted to discharge and charge at the same power, where the discharge and charging power required for energy storage at nodes K and P is Max(ΔP). i Otherwise, if P F max,K <P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. F max,K Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k And the maximum available charging power P of the Pth charging energy storage nodeC max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update K = K + 1, and return to S52 to recalculate; if P F max,K >P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. C max,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k and the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update P = P + 1, and return to S52 to recalculate; if P F max,K =P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. F max,K and P C max,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k and the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update K = K+1, P = P+1, and return to S52 to recalculate; until the minimum energy storage adjustment power ΔP required for each branch is reached. i The maximum value in Max(ΔP) i Simultaneously satisfying Max(ΔP) i )≤P F max,K and Max(ΔP) i )≤P C max,P At that time, the required discharge power and charging power for the current energy storage node K and energy storage node P are both the current Max(ΔP). i The power supply is adjusted by charging and discharging to ensure that the power of all branches in the power transmission network does not exceed the limit.

[0135] Compared with the prior art, the advantages of this invention are: by using energy storage for regulation, the adjustment amount of other active power control equipment (such as generators and DC systems) can be minimized, providing a more flexible and faster control means for power flow control. At the same time, this method takes into account the impact on critical sections and heavily loaded lines, and can avoid the generation of new overloaded lines while controlling overloaded branches.

[0136] by Figure 2 Taking the IEEE 39-bus system as an example, the process of realizing multi-point decentralized coordinated control of power flow in transmission lines includes:

[0137] Step 1-1: Based on the power flow calculation results, the overload branch set A of the system is determined to consist of branches L17-16. The initial power flow values ​​and power limits of the branches are shown in Table 1 below. The minimum power flow adjustment ΔP is calculated. T min,17-16 =5.2MW.

[0138] Table 1 Initial Power Flow Values ​​and Power Limits for Branch Routes

[0139] branch road Initial value of current Power Limit 17-16 190.2 185

[0140] Step 1-2: Set the safety threshold μ1 = 90%, and determine the branches included in the safety constraint branch set B as [L 16-14 L 23-12 L 13-11 The initial power flow values ​​and safety limits for each branch in B are shown in Table 2 below. The calculated load factor for each branch is [β]. L16-14 ,β L23-12 ,β L13-11 = [95.8%, 93.8%, 94.5%].

[0141] Table 2 Initial power flow values ​​and safety limits for branch circuits

[0142]

[0143]

[0144] Step 2-1: Determine that the controllable energy storage node set C in this system consists of 6 nodes, namely [17, 16, 14, 13, 23, 19]. The adjustable power of each node in C is shown in Table 3 below:

[0145] Table 3 Adjustable Power Table of Energy Storage Nodes

[0146] Adjustable energy storage node name 17 16 14 13 23 19 <![CDATA[Maximum available discharge power P F max,k (MW)]]> 25 20 30 25 30 35 <![CDATA[Maximum available charging power P C max,k (MW)]]> 25 20 30 25 30 35

[0147] Step 2-2: Calculate the power flow control sensitivity of each node in set C to each branch in sets A and B. The power flow control sensitivities are shown in Table 4 below:

[0148] Table 4 Power Flow Control Sensitivity Table

[0149]

[0150] Step 3: Set the safety threshold μ2 = 85%, and calculate the weight coefficient α for each branch. L,p As shown in Table 5 below:

[0151] Table 5. Weighting coefficients for each branch road

[0152] branch road 17-16 16-14 23-12 13-11 Weighting coefficient 0.3795 0.2303 0.1876 0.2026

[0153] Calculate the overall control sensitivity f of each node in set C to the power flow of each branch in sets A and B. S,k As shown in Table 6:

[0154] Table 6. Comprehensive Control Sensitivity Table

[0155] Energy storage nodes 17 16 14 13 23 19 Overall Sensitivity -0.0921 0.0167 0.1038 0.0282 0.0045 0.0055

[0156] Step 4-1: Determine the discharge node set C1 as [13, 14, 16, 19, 23] and the charging node set C1 as

[17] based on the sign of the comprehensive sensitivity.

[0157] Step 4-2: Determine the adjustment sequence of the discharge nodes based on the absolute value of the overall sensitivity as [14, 13, 16, 19, 23].

[0158] Step 5-1: Based on the sorting results, select the pair of nodes 14 and 17 with the highest overall sensitivity and adjust them by discharging and charging them with the same power, respectively, according to S. iK ×ΔP i +S iP (-ΔP i )=ΔP Tmin,i The calculated discharge power at node 14 and the charging power at node 17 are ΔP = 19MW.

[0159] Step 5-2: Verify overload branch L 17-16 The minimum energy storage adjustment power ΔP = 19MW is less than the available adjustment power of nodes K and P. Therefore, this round of adjustment can control the power flow of each branch within the power limit.

[0160] Step 6: Verify that the power flow of each branch does not exceed the limit after adjustment. The adjustment is complete. The power flow of each branch before and after adjustment is shown in Table 7 below:

[0161] Table 7. Power flow tables for each branch before and after adjustment.

[0162] branch road 17-16 16-14 23-12 13-11 Pre-adjustment flow (MW) 190.2 182.1 150.1 141.8 Adjusted flow rate (MW) 181.29 172.4 149.46 140.5 Power limit (MW) 185 190 160 150

[0163] Figure 3 This is a schematic diagram of the structure of a power flow distributed coordination control system 300 for transmission lines based on energy storage, according to an embodiment of the present invention. Figure 3 As shown, the power flow distributed coordination control system 300 based on energy storage for transmission lines provided by the present invention includes: a minimum power flow adjustment demand determination unit 301, a power flow control sensitivity determination unit 302, a comprehensive control sensitivity determination unit 303, a node classification unit 304, and a control unit 305.

[0164] Preferably, the minimum power flow adjustment demand determination unit 301 is used to determine the set of over-limit branches and the set of safety-constrained branches in the transmission network, and to calculate the minimum power flow adjustment demand for each branch in the set of over-limit branches.

[0165] Preferably, the minimum power flow adjustment demand determination unit 301 calculates the minimum power flow adjustment demand for each branch in the set of over-limit branches using the following method:

[0166]

[0167] Wherein, ΔP T min,i P represents the minimum power flow adjustment demand for the i-th branch in the set of over-limit branches A; L max,i Let be the transmission power limit value of the i-th branch in the set of over-limit branches A; is the initial power flow value for the i-th branch; n is the number of branches that exceed the limit.

[0168] Preferably, in the minimum power flow adjustment demand determination unit 301, the set of safety constraint branches includes: branches with a load rate greater than or equal to a first preset safety threshold μ1 and all other branches in the critical section where the over-limit branches are located;

[0169] The load factor is determined using the following methods:

[0170]

[0171] Where, β L,j Let P be the load rate of the j-th branch; L max,j Let be the transmission power limit of the j-th branch; Let μ be the initial power flow value of the j-th branch; μ1 is the first preset safety threshold, satisfying 0 < μ1 < 1.

[0172] Preferably, the power flow control sensitivity determination unit 302 is used to determine the set of energy storage nodes and determine the power flow control sensitivity of each energy storage node in the set of energy storage nodes to each branch in the set of over-limit branches and the set of safety-constrained branches.

[0173] Preferably, the power flow control sensitivity determination unit 302 determines the power flow control sensitivity of each energy storage node in the energy storage node set to each branch in the set of over-limit branches and the set of safety-constrained branches, including:

[0174]

[0175] Among them, S pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; let be the change in energy storage power of the k-th energy storage node be ΔP.S,k The power reduction of the p-th branch is ΔP. L,p Among them, S pk ≥0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node discharges; conversely, S pk <0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node is charging; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes.

[0176] Preferably, the integrated control sensitivity determination unit 303 is used to calculate the integrated control sensitivity of each energy storage node in the energy storage node set to the power flow of each branch in the over-limit branch set and the safety constraint branch set, based on the power flow control sensitivity.

[0177] Preferably, the integrated control sensitivity determination unit 303 calculates the integrated control sensitivity of each energy storage node in the energy storage node set to the power flow of each branch in the set of over-limit branches and the set of safety-constrained branches, based on the power flow control sensitivity, including:

[0178]

[0179]

[0180]

[0181] Among them, f S,k The overall control sensitivity of the k-th energy storage node; α L,p β is the weight coefficient of the p-th branch; L,p Let P be the load factor of the p-th branch; L max,p Let be the transmission power limit value of the p-th branch; S represents the initial power flow value for the p-th branch; pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes; μ2 is the second preset safety threshold, satisfying 0 < μ2 ≤ μ1.

[0182] Preferably, the node classification unit 304 is used to obtain the adjustable power of each energy storage node, and classify the energy storage nodes according to the adjustable power and comprehensive control sensitivity to determine the discharge node set and the charging node set.

[0183] Preferably, the node classification unit 304 classifies energy storage nodes according to the adjustable power and comprehensive control sensitivity, and determines the discharge node set and the charging node set, including:

[0184] Based on the adjustable power and comprehensive control sensitivity, the energy storage nodes are classified into types to determine the discharge energy storage nodes and the charging energy storage nodes. The discharge energy storage nodes and the charging energy storage nodes are then sorted in descending order according to the absolute value of the comprehensive control sensitivity to determine the discharge node set and the charging node set.

[0185] Wherein, if the comprehensive control sensitivity of the k-th energy storage node satisfies f S,k >0, and the maximum available discharge power satisfies P F max,k If σ > 0, then the kth energy storage node is determined as the discharge node; if the comprehensive control sensitivity of the kth energy storage node satisfies f S,k <0, and the maximum available discharge power satisfies P C max,k If σ > 0, then the kth energy storage node is determined as the charging node;

[0186] Among them, f S,k P represents the overall control sensitivity of the k-th energy storage node. F max,k and P C max,k σ represents the maximum available discharge power and the maximum available charging power of the k-th energy storage node, respectively; σ is the preset adjustable power threshold.

[0187] Preferably, the control unit 305 is used to adjust the charging and discharging according to the minimum power flow adjustment demand, the set of discharge nodes and the set of charging nodes, so as to control the power of all branches in the transmission network to not exceed the limit.

[0188] Preferably, the control unit 305 adjusts the charging and discharging based on the minimum power flow adjustment demand, the set of discharging nodes, and the set of charging nodes to control the power of all branches in the transmission network to not exceed the limit, including:

[0189] S51, Initialize K=1, P=1,

[0190] S52, calculate the minimum energy storage adjustment power ΔP required for each branch in the set of over-limit branches A based on the minimum power flow adjustment demand. i ;

[0191] S53, select the Kth discharge energy storage node and the Pth charging energy storage node in the discharge sequence C1 and charging sequence C2 respectively, and obtain the maximum available discharge power P of the Kth discharge energy storage node. F max,K and the maximum available charging power P of the Pth charging energy storage node C max,P ;

[0192] S54, determine the minimum energy storage adjustment power ΔP required for each branch. i The maximum value in Max(ΔP) i Does it simultaneously satisfy Max(ΔP)? i )≤PF max,K and Max(ΔP) i )≤P C max,P If satisfied, it is determined that the power flow of each branch can be controlled within the power limit through this round of adjustment, based on the fact that the required discharge power and charging power of energy storage node K and energy storage node P are both Max(ΔP). i ) Perform charge and discharge adjustments to control the power of all branches in the transmission network to ensure that it does not exceed the limit; otherwise, if P F max,K <P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. F max,K Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k And the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update K = K + 1, and return to S52 to recalculate; if P F max,K >P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. C max,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k and the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update P = P + 1, and return to S52 to recalculate; if P F max,K =P C max,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. F max,K and P C max,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. F max,k and the maximum available charging power P of the Pth charging energy storage node C max,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. T min,i Update K = K+1, P = P+1, and return to S52 to recalculate; until the minimum energy storage adjustment power ΔP required for each branch is reached. i The maximum value in Max(ΔP) i Simultaneously satisfying Max(ΔP) i )≤P F max,K and Max(ΔP) i )≤P C max,PAt that time, the required discharge power and charging power for the current energy storage node K and energy storage node P are both the current Max(ΔP). i The power supply is adjusted by charging and discharging to ensure that the power of all branches in the power transmission network does not exceed the limit.

[0193] Preferably, the control unit 305 determines the minimum energy storage adjustment power ΔP using the following method. i ,include:

[0194]

[0195] Wherein, ΔP i S is the minimum energy storage adjustment power required for the i-th branch in the set of over-limit branches A; iK and S iP ΔP represents the power flow control sensitivity of the Kth discharge energy storage node and the Pth charge energy storage node to the i-th branch, respectively; T min,i Let i be the minimum power flow adjustment demand for the i-th branch.

[0196] The energy storage-based power flow distributed coordination control system 300 for transmission lines in this embodiment corresponds to the energy storage-based power flow distributed coordination control method 100 for transmission lines in another embodiment of this invention, and will not be described again here.

[0197] The invention has been described with reference to a few embodiments. However, as will be known to those skilled in the art, and as defined in the appended claims, other embodiments besides those disclosed above fall equivalently within the scope of the invention.

[0198] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

[0199] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0200] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0201] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0202] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0203] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A distributed coordinated control method for power flow in transmission lines based on energy storage, characterized in that, The method includes: Determine the set of over-limit branches and the set of safety-constrained branches in the transmission network, and calculate the minimum power flow adjustment requirement for each branch in the set of over-limit branches; Determine the set of energy storage nodes, and determine the power flow control sensitivity of each energy storage node in the set of energy storage nodes to each branch in the set of over-limit branches and the set of safety-constrained branches; Based on the power flow control sensitivity, calculate the comprehensive control sensitivity of each energy storage node in the energy storage node set for each power flow in the set of over-limit branches and the set of safety-constrained branches; The adjustable power of each energy storage node is obtained, and the energy storage nodes are classified according to the adjustable power and the comprehensive control sensitivity to determine the set of discharge nodes and the set of charging nodes. The charging and discharging are adjusted according to the minimum power flow adjustment demand, the set of discharge nodes, and the set of charging nodes to control the power of all branches in the transmission network to not exceed the limit. The step of calculating the comprehensive control sensitivity of each energy storage node in the energy storage node set to the power flow of each branch in the set of over-limit branches and the set of safety-constrained branches, based on the power flow control sensitivity, includes: Among them, f S,k The overall control sensitivity of the k-th energy storage node; α L,p β is the weight coefficient of the p-th branch; L,p Let P be the load factor of the p-th branch; Lmax,p Let be the transmission power limit value of the p-th branch; S represents the initial power flow value for the p-th branch; pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes; μ2 is the second preset safety threshold, satisfying 0 < μ2 ≤ μ1; μ1 is the first preset safety threshold.

2. The method according to claim 1, characterized in that, The method calculates the minimum power flow adjustment requirement for each branch in the set of over-limit branches in the following manner: Wherein, ΔP Tmin,i P represents the minimum power flow adjustment demand for the i-th branch in the set of over-limit branches A; Lmax,i Let be the transmission power limit value of the i-th branch in the set of over-limit branches A; is the initial power flow value for the i-th branch; n is the number of branches that exceed the limit.

3. The method according to claim 1, characterized in that, The set of safety constraint branches includes: branches with a load rate greater than or equal to the first preset safety threshold μ1 and all other branches in the critical section where the over-limit branches are located; The load factor is determined using the following methods: Where, β L,j Let P be the load rate of the j-th branch; Lmax,j Let be the transmission power limit of the j-th branch; Let μ be the initial power flow value for the j-th branch; 0 < μ1 < 1.

4. The method according to claim 1, characterized in that, Determining the power flow control sensitivity of each energy storage node in the energy storage node set to each branch in the over-limit branch set and the safety-constrained branch set includes: Among them, S pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; let be the change in energy storage power of the k-th energy storage node be ΔP. S,k The power reduction of the p-th branch is ΔP. L,p Among them, S pk ≥0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node discharges; conversely, S pk <0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node is charging; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes.

5. The method according to claim 1, characterized in that, The step of classifying energy storage nodes according to the adjustable power and comprehensive control sensitivity to determine the set of discharge nodes and the set of charging nodes includes: Based on the adjustable power and comprehensive control sensitivity, the energy storage nodes are classified into types to determine the discharge energy storage nodes and the charging energy storage nodes. The discharge energy storage nodes and the charging energy storage nodes are then sorted in descending order according to the absolute value of the comprehensive control sensitivity to determine the discharge node set and the charging node set. Wherein, if the comprehensive control sensitivity of the k-th energy storage node satisfies f S,k >0, and the maximum available discharge power satisfies P Fmax,k If σ > 0, then the kth energy storage node is determined as the discharge node; if the comprehensive control sensitivity of the kth energy storage node satisfies f S,k <0, and the maximum available discharge power satisfies P Cmax,k If σ > 0, then the kth energy storage node is determined as the charging node; Among them, f S,k P represents the overall control sensitivity of the k-th energy storage node. Fmax,k and P Cmax,k σ represents the maximum available discharge power and the maximum available charging power of the k-th energy storage node, respectively; σ is the preset adjustable power threshold.

6. The method according to claim 1, characterized in that, Adjustments to charging and discharging are made based on the minimum power flow adjustment demand, the set of discharging nodes, and the set of charging nodes to control the power of all branches in the transmission network to ensure that the power does not exceed the limit, including: S51, Initialize K=1, P=1, S52, calculate the minimum energy storage adjustment power ΔP required for each branch in the set of over-limit branches A based on the minimum power flow adjustment demand. i ; S53, select the Kth discharge energy storage node and the Pth charging energy storage node in the discharge sequence C1 and charging sequence C2 respectively, and obtain the maximum available discharge power P of the Kth discharge energy storage node. Fmax,K and the maximum available charging power P of the Pth charging energy storage node Cmax,P ; S54, determine the minimum energy storage adjustment power ΔP required for each branch. i The maximum value in Max(ΔP) i Does it simultaneously satisfy Max(ΔP)? i )≤P Fmax,K and Max(ΔP) i )≤P Cmax,P If satisfied, it is determined that the power flow of each branch can be controlled within the power limit through this round of adjustment, based on the fact that the required discharge power and charging power of energy storage node K and energy storage node P are both Max(ΔP). i ) Perform charge and discharge adjustments to control the power of all branches in the transmission network to ensure that it does not exceed the limit; otherwise, if P Fmax,K <P Cmax,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. Fmax,K Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. Fmax,k And the maximum available charging power P of the Pth charging energy storage node Cmax,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. Tmin,i Update K = K + 1, and return to S52 to recalculate; if P Fmax,K >P Cmax,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. Cmax,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. Fmax,k and the maximum available charging power P of the Pth charging energy storage node Cmax,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. Tmin,i Update P = P + 1, and return to S52 to recalculate; if P Fmax,K =P Cmax,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. Fmax,K and P Cmax,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. Fmax,k and the maximum available charging power P of the Pth charging energy storage node Cmax,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. Tmin,i Update K = K+1, P = P+1, and return to S52 to recalculate; until the minimum energy storage adjustment power ΔP required for each branch is reached. i The maximum value in Max(ΔP) i Simultaneously satisfying Max(ΔP) i )≤P Fmax,K and Max(ΔP) i )≤P Cmax,P At that time, the required discharge power and charging power for the current energy storage node K and energy storage node P are both the current Max(ΔP). i The power supply is adjusted by charging and discharging to ensure that the power of all branches in the power transmission network does not exceed the limit.

7. The method according to claim 6, characterized in that, The method determines the minimum energy storage adjustment power ΔP using the following approach. i ,include: Wherein, ΔP i S is the minimum energy storage adjustment power required for the i-th branch in the set of over-limit branches A; iK and S iP ΔP represents the power flow control sensitivity of the Kth discharge energy storage node and the Pth charge energy storage node to the i-th branch, respectively; Tmin,i Let i be the minimum power flow adjustment demand for the i-th branch.

8. A distributed power flow coordination control system for transmission lines based on energy storage, characterized in that, The system includes: The minimum power flow adjustment demand determination unit is used to determine the set of over-limit branches and the set of safety-constrained branches in the transmission network, and to calculate the minimum power flow adjustment demand for each branch in the set of over-limit branches. A power flow control sensitivity determination unit is used to determine the set of energy storage nodes and to determine the power flow control sensitivity of each energy storage node in the set of energy storage nodes to each branch in the set of over-limit branches and the set of safety-constrained branches. The integrated control sensitivity determination unit is used to calculate the integrated control sensitivity of each energy storage node in the energy storage node set to the power flow of each branch in the over-limit branch set and the safety constraint branch set, based on the power flow control sensitivity. The node classification unit is used to obtain the adjustable power of each energy storage node, and classify the energy storage nodes according to the adjustable power and the comprehensive control sensitivity to determine the set of discharge nodes and the set of charging nodes. The control unit is used to adjust the charging and discharging according to the minimum power flow adjustment demand, the set of discharge nodes and the set of charging nodes, so as to control the power of all branches in the transmission network to not exceed the limit. The integrated control sensitivity determination unit calculates the integrated control sensitivity of each energy storage node in the energy storage node set to the power flow of each branch in the set of over-limit branches and the set of safety-constrained branches, based on the power flow control sensitivity, including: Among them, f S,k The overall control sensitivity of the k-th energy storage node; α L,p β is the weight coefficient of the p-th branch; L,p Let P be the load factor of the p-th branch; Lmax,p Let be the transmission power limit value of the p-th branch; S represents the initial power flow value for the p-th branch; pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes; μ2 is the second preset safety threshold, satisfying 0 < μ2 ≤ μ1; μ1 is the first preset safety threshold.

9. The system according to claim 8, characterized in that, The minimum power flow adjustment demand determination unit calculates the minimum power flow adjustment demand for each branch in the set of over-limit branches using the following method: Wherein, ΔP Tmin,i P represents the minimum power flow adjustment demand for the i-th branch in the set of over-limit branches A; Lmax,i Let be the transmission power limit value of the i-th branch in the set of over-limit branches A; is the initial power flow value for the i-th branch; n is the number of branches that exceed the limit.

10. The system according to claim 8, characterized in that, In the minimum power flow adjustment demand determination unit, the set of safety constraint branches includes: branches with load rates greater than or equal to the first preset safety threshold μ1 and all other branches in the critical section where the over-limit branches are located; The load factor is determined using the following methods: Where, β L,j Let P be the load rate of the j-th branch; Lmax,j Let be the transmission power limit of the j-th branch; Let μ be the initial power flow value of the j-th branch; μ1 is the first preset safety threshold, satisfying 0 < μ1 < 1.

11. The system according to claim 8, characterized in that, The power flow control sensitivity determination unit determines the power flow control sensitivity of each energy storage node in the energy storage node set to each branch in the set of over-limit branches and the set of safety-constrained branches, including: Among them, S pk Let be the power flow control sensitivity of the k-th energy storage node to the p-th branch; let be the change in energy storage power of the k-th energy storage node be ΔP. S,k The power reduction of the p-th branch is ΔP. L,p Among them, S pk ≥0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node discharges; conversely, S pk <0 indicates that the power flow of the p-th branch decreases when the k-th energy storage node is charging; A is the set of over-limit branches; B is the set of safety-constrained branches; C is the set of energy storage nodes.

12. The system according to claim 8, characterized in that, The node classification unit categorizes energy storage nodes based on the adjustable power and comprehensive control sensitivity, determining the discharge node set and the charging node set, including: Based on the adjustable power and comprehensive control sensitivity, the energy storage nodes are classified into types to determine the discharge energy storage nodes and the charging energy storage nodes. The discharge energy storage nodes and the charging energy storage nodes are then sorted in descending order according to the absolute value of the comprehensive control sensitivity to determine the discharge node set and the charging node set. Wherein, if the comprehensive control sensitivity of the k-th energy storage node satisfies f S,k >0, and the maximum available discharge power satisfies P Fmax,k If σ > 0, then the kth energy storage node is determined as the discharge node; if the comprehensive control sensitivity of the kth energy storage node satisfies f S,k <0, and the maximum available discharge power satisfies P Cmax,k If σ > 0, then the kth energy storage node is determined as the charging node; Among them, f S,k P represents the overall control sensitivity of the k-th energy storage node. Fmax,k and P Cmax,k σ represents the maximum available discharge power and the maximum available charging power of the k-th energy storage node, respectively; σ is the preset adjustable power threshold.

13. The system according to claim 8, characterized in that, The control unit adjusts the charging and discharging based on the minimum power flow adjustment demand, the set of discharging nodes, and the set of charging nodes to control the power of all branches in the transmission network to ensure that the power does not exceed the limit, including: S51, Initialize K=1, P=1, S52, calculate the minimum energy storage adjustment power ΔP required for each branch in the set of over-limit branches A based on the minimum power flow adjustment demand. i ; S53, select the Kth discharge energy storage node and the Pth charging energy storage node in the discharge sequence C1 and charging sequence C2 respectively, and obtain the maximum available discharge power P of the Kth discharge energy storage node. Fmax,K and the maximum available charging power P of the Pth charging energy storage node Cmax,P ; S54, determine the minimum energy storage adjustment power ΔP required for each branch. i The maximum value in Max(ΔP) i Does it simultaneously satisfy Max(ΔP)? i )≤P Fmax,K and Max(ΔP) i )≤P Cmax,P If satisfied, it is determined that the power flow of each branch can be controlled within the power limit through this round of adjustment, based on the fact that the required discharge power and charging power of energy storage node K and energy storage node P are both Max(ΔP). i ) Perform charge and discharge adjustments to control the power of all branches in the transmission network to ensure that it does not exceed the limit; otherwise, if P Fmax,K <P Cmax,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. Fmax,K Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. Fmax,k And the maximum available charging power P of the Pth charging energy storage node Cmax,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. Tmin,i Update K = K + 1, and return to S52 to recalculate; if P Fmax,K >P Cmax,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. Cmax,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. Fmax,k and the maximum available charging power P of the Pth charging energy storage node Cmax,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. Tmin,i Update P = P + 1, and return to S52 to recalculate; if P Fmax,K =P Cmax,P Then let the Kth discharge energy storage node and the Pth charging energy storage node be set according to P. Fmax,K and P Cmax,P Perform discharge and charge operations, calculate the power change of each branch, and update the maximum available discharge power P of the Kth discharge energy storage node. Fmax,k and the maximum available charging power P of the Pth charging energy storage node Cmax,P And update the minimum power adjustment requirement ΔP for each branch in the set of over-limit branches A. Tmin,i Update K = K+1, P = P+1, and return to S52 to recalculate; until the minimum energy storage adjustment power ΔP required for each branch is reached. i The maximum value in Max(ΔP) i Simultaneously satisfying Max(ΔP) i )≤P Fmax,K and Max(ΔP) i )≤P Cmax,P At that time, the required discharge power and charging power for the current energy storage node K and energy storage node P are both the current Max(ΔP). i The power supply is adjusted by charging and discharging to ensure that the power of all branches in the power transmission network does not exceed the limit.

14. The system according to claim 13, characterized in that, The control unit determines the minimum energy storage adjustment power ΔP using the following method. i ,include: Where, ΔP i S is the minimum energy storage adjustment power required for the i-th branch in the set of over-limit branches A; iK and S iP ΔP represents the power flow control sensitivity of the Kth discharge energy storage node and the Pth charge energy storage node to the i-th branch, respectively; Tmin,i Let i be the minimum power flow adjustment demand for the i-th branch.

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