CN-122026418-A - New energy power grid active control method and device considering voltage supporting capability

CN122026418ACN 122026418 ACN122026418 ACN 122026418ACN-122026418-A

Abstract

The invention discloses a new energy power grid active control method and device considering voltage supporting capability, and belongs to the technical field of power system stability analysis and control. The method comprises the steps of establishing a new energy multi-station short-circuit ratio index of reactive capacity to accurately evaluate voltage support intensity of a high-proportion new energy power grid, establishing power supply coherent group constraint according to multi-type power supply grouping results after power grid faults, establishing voltage support intensity constraint of an island subsystem, integrating the coherent group constraint and the voltage support intensity constraint, establishing an optimal disconnection section search model of active control, and obtaining an optimal disconnection section and island subsystem control scheme through the solution model. The defect that the traditional active disconnection control method does not account for the voltage supporting capability is overcome, the short-circuit ratio index is used as constraint and is fused into the control model, so that the island subsystem before and after active control is ensured to have enough voltage supporting strength, and the safe and stable operation level of the high-proportion new energy power grid is effectively improved.

Inventors

HUANG ZHEN
WANG ZIYUN
Zou Haoxuan
LI SHUGUANG
ZHANG RUFENG
CAO SHUAI
LIU BOHAN
REN PUCHUN
JIANG TAO
ZHANG BOWEN
JIAN NING
LIU XIANCHAO
LI QING
FENG WEI
YANG TIANMENG
WANG CHANGJIANG

Assignees

东北电力大学
国家电网公司东北分部

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (9)

1. The new energy power grid active control method considering the voltage supporting capability is characterized by comprising the following steps of: Step 100, based on the short-circuit capacity of the alternating current system and the equivalent grid-connected capacity of the new energy, combining reactive characteristics of the new energy station and the reactive compensation device, constructing a new energy multi-station short-circuit ratio index considering the reactive capacity; Step 200, establishing voltage support strength constraint of a new energy power grid according to the new energy multi-station short circuit ratio index, constructing a new energy bearing capacity assessment model considering the voltage support strength, and determining an initial running state of the new energy power grid before active control, wherein the initial running state comprises the power active output of a power supply before disconnection and the power flowing through a line; Step 300, determining multi-type power supply grouping results according to the relative motion trend of the power supply after the new energy power grid fails, and calculating the number of island subsystems after active disconnection control; Step 400, establishing power supply coherent grouping constraint according to a multi-type power supply grouping result, and constructing voltage support strength constraint of the island subsystem by considering the reactive power of a new energy station of the island subsystem; And S500, constructing an actively controlled optimal splitting section search model by combining splitting constraint conditions, wherein the splitting constraint conditions comprise power supply coherent group constraint, voltage support strength constraint of an island subsystem, linearization alternating current power flow constraint, power flow constraint after line break, island internal connectivity constraint and island power balance constraint, and obtaining optimal splitting sections and island subsystem active control results.
2. The active control method of the new energy power grid considering the voltage supporting capability according to claim 1, wherein the expression of the new energy multi-station short-circuit ratio index considering the reactive capacity is: ; wherein: The short-circuit ratio index of the new energy multi-station is considered for considering reactive capacity; the short circuit capacity of the point corresponding to the point of the parallel network is the node i; The active output values of the new energy sources are respectively nodes i and j; is the voltage interaction influence factor between the nodes j and i; and the reactive capacity of the new energy station at the node i is obtained.
3. The method for actively controlling a new energy grid in consideration of voltage supporting capability according to claim 2, wherein said establishing a voltage supporting strength constraint of the new energy grid comprises: establishing a new energy power grid voltage support strength constraint according to a new energy multi-station short circuit ratio index, including: ; ; ; ; wherein: is a collection of capacitor banks; Is a collection of static var compensator groups; A unit reactive power for capacitor b; The number of capacitor banks put into use; the maximum number of inputs for the capacitor bank; the upper limit and the lower limit of reactive power dispatching of the static reactive power compensator are respectively adopted, wherein CSCR is a critical short circuit ratio; Is the schedule value for the static var compensator s.
4. The method for actively controlling a new energy power grid with consideration of voltage supporting capability according to claim 3, wherein the new energy load bearing capability assessment model with consideration of voltage supporting strength takes the maximum new energy grid-connected power as an optimization target, and the optimization target is constrained by combining a node active and reactive power balance constraint equation, a linearized alternating current trend equation, a line power constraint, a generator output constraint and the new energy multi-station short-circuit ratio index, and the method specifically comprises the following steps: based on the voltage support strength constraint of the new energy power grid, a new energy power grid bearing capacity assessment model with the maximum new energy grid-connected power as an optimization target is established, and the expression is as follows: ; wherein: is a set of new energy stations; The active power output of the ith new energy station.
5. The method for actively controlling a new energy grid with consideration of voltage supporting capacity according to claim 4, wherein the node active and reactive power balance constraint equation, linearized ac power flow equation, line power constraint, generator output constraint and the new energy multi-station short-circuit ratio index comprise: The expression of the node active and reactive power balance equation is: ; wherein: 、 the bus is a receiving end bus and a transmitting end bus of the power transmission line respectively; 、 The active output and the reactive output of the generator during normal operation are respectively; active and reactive power of the branches (i, j) respectively; Active and reactive loads of node i, respectively; a reactive scheduling value for capacitor bank c; Reactive power output is generated for the new energy station of the node i; The expression of the linearized alternating current power flow model is as follows: ; ; wherein: For the conductance and susceptance of branch (i, j), 、 The voltage magnitudes of nodes i and j respectively, And The voltage phase angles of the node i and the node j are respectively; the expression for the line flow power constraint is: ; wherein: Respectively the maximum value and the minimum value of the active power flowing through the line; respectively a maximum value and a minimum value of reactive power flowing through the line; the active output and reactive output constraint expression of the new energy station is as follows: ; the constraint expression of the active output and the reactive output of the generator is as follows: ; wherein: the maximum value of the active output of the new energy station and the generator is respectively; The reactive power output minimum value and the reactive power output maximum value of the new energy station are respectively; the minimum and maximum reactive output values of the generator are respectively.
6. The method for actively controlling a new energy power grid with consideration of voltage supporting capability according to claim 5, wherein the specific implementation process of establishing power coherent group constraint according to the multi-type power grouping result and establishing voltage supporting strength constraint of the island subsystem with consideration of the reactive capability of the new energy station of the island subsystem comprises the following steps: Determining a grouping result of multiple types of power supplies according to the relative movement trend of the power supplies after the new energy power grid fails, and determining the number of island subsystems after active disconnection control ; Splitting a power grid system into groups according to grouping conditions of coherent units in multiple types of power supplies The number of island subsystems is one, Wherein, a node only corresponds to one island subsystem; Partitioning 0-1 variables for node i if If =1, node i belongs to a point in island k, if =0, Then node i does not belong to a point within island k; Judging whether the nodes i and j belong to the same island subsystem, and introducing auxiliary variables Establishing power supply coherent grouping constraint to obtain a linear expression form: ; ; wherein: The decision variable is a line partition 0-1 variable; Is an auxiliary variable, which is an auxiliary 0-1 variable; Partitioning 0-1 variables for node j; is the collection of branches; In order to limit the active power of a new energy station in each island subsystem after disconnection, so that the active power meets the critical short-circuit ratio requirement, the short-circuit ratio constraint of the island subsystem after active disconnection control is defined, and the voltage support strength constraint of the island subsystem is constructed: ; wherein: active power values of new energy stations of nodes i and j in a k power grid of the island subsystem respectively; the power variation of the new energy stations of nodes i and j in the k power grid of the island subsystem is respectively calculated; the voltage interaction influence factors between nodes j and i in the power grid of the island subsystem k are obtained; the short-circuit capacity at a node i in the power grid of the island subsystem k; and the reactive capacity of the new energy station at the node j in the power grid of the island subsystem k.
7. The method for actively controlling a new energy power grid with consideration of voltage supporting capacity according to claim 6, wherein the specific implementation process of constructing the actively controlled optimal split section search model by combining the split constraint condition comprises the following steps: Combining the splitting constraint condition, and constructing an actively controlled optimal splitting section search model by taking the minimum comprehensive load flow impact and the minimum splitting load amount as targets, wherein the objective function is as follows: ; wherein: Penalty coefficients for tidal current impact; penalty coefficients for cut load; the cut load amount for node i; For decision variables, representing the break-up of the branch (i, j), if Then it means that branch (i, j) is disconnected, if Then it means that the branches (i, j) are connected; Active power of a branch (i, j) during stable operation of the system before island division is divided, wherein D is a set formed by all loaded nodes in the system; And solving the optimal solution section search model by adopting a commercial optimization solver to obtain an optimal solution section and an island subsystem active control result.
8. The method for actively controlling a new energy power grid with consideration of voltage supporting capability according to claim 7, wherein the disconnection constraint conditions comprise power supply coherent grouping constraint, voltage supporting strength constraint of an island subsystem, linearization alternating current power flow constraint, power flow constraint after line disconnection, island internal connectivity constraint and island power balance constraint; The node power balance constraint considers the active and reactive balance of the load shedding and power generation change of each node, limits the size range of the load shedding and the load shedding of each node, and adopts the constraint formula as follows: ; ; ; wherein: Dispatching the output for the wind power plant in normal operation; The active and reactive output variable quantities of the generator are respectively; scheduling a variable for a wind farm; the maximum value of the active and reactive variable quantities of the generator are respectively; is the maximum load amount that can be cut off; the line power flow constraint comprises a linearized alternating current power flow model, and the model formula is as follows: ; ; wherein: Is a positive number, and the number of the components is a positive number, As an auxiliary variable, a control signal is provided, For the purpose of line conductance, The line susceptance; the connectivity constraint ensures the connectivity of the island by constructing virtual active power balance, and the construction formula is as follows: ; wherein: Active power of the virtual branch; the active power of the virtual generator is generated; The unbalanced power selection constraint of the island subsystem is that unbalanced power generated in the active disconnection control process is represented by a power surplus or a deficiency, the power surplus represents that the generated energy of the island subsystem is larger than the load, the power deficiency represents that the generated energy of the island subsystem is smaller than the load, and the surplus and the deficiency cannot exist in one island subsystem at the same time and must be nonnegative, and the constraint formula is as follows: ; ; wherein: Unbalanced power for the island subsystem k; Delta is a binary variable, which represents the selection relation between the power surplus and the deficiency in the island subsystem, and the two cannot exist in one island subsystem at the same time.
9. A new energy power grid active control device taking voltage supporting capability into consideration, which uses the new energy power grid active control method taking voltage supporting capability into consideration according to any one of claims 1 to 8, wherein the device comprises an initial state determining module, a grouping result determining module and a de-ranking control decision module; The initial state determining module is used for establishing voltage support strength constraint of the new energy power grid based on the new energy multi-station short circuit ratio index, and constructing a new energy bearing capacity assessment model considering the voltage support strength so as to determine an initial running state of the new energy power grid before active control; the grouping result determining module is used for determining a grouping result of the multiple types of power supplies and the number of island subsystems after active disconnection control according to the relative movement trend of the power supplies after the new energy power grid fails, and constructing the voltage support strength constraint of each island subsystem; and the splitting control decision module is used for constructing an optimal splitting section search model for active control according to the coherent grouping constraint and the voltage support strength constraint of the island subsystem, and obtaining an optimal splitting section and an active splitting control result of each island subsystem by solving the optimal splitting section search model.

Description

New energy power grid active control method and device considering voltage supporting capability Technical Field The invention relates to the technical field of stability analysis and control of power systems, in particular to a new energy power grid active control method and device considering voltage supporting capability. Background Under the guidance of a 'double-carbon' target, a novel power system taking new energy as a main body is constructed, so that the novel power system becomes an urgent task of pushing energy to clean low-carbon transformation, and is also an important measure for guaranteeing national energy safety. As the access proportion of new energy controlled by maximum power tracking continues to rise, the equivalent short-circuit capacity of the power grid is reduced, the disturbance rejection capability of the system is obviously weakened, and the problem of voltage safety and stability is particularly remarkable. The short circuit ratio is used as a key index for measuring the voltage support strength of the system, the size of the short circuit ratio directly influences the stable operation of the new energy grid-connected system, and the accurate evaluation of the voltage support strength of the high-proportion new energy grid and the isolated island subnetwork after disconnection is of great significance to the large-scale sustainable development of new energy. Although the traditional short-circuit ratio index suitable for the single-feed new energy grid-connected system can still approximately reflect the voltage support intensity of the power grid, the accuracy of the voltage support intensity evaluation of the power grid is reduced because the influence of other feed new energy is not considered. The weighted short-circuit ratio and the composite short-circuit ratio proposed by the multi-feed new energy grid-connected system take the multi-feed new energy as a whole, and the interaction among all feed branches is roughly estimated through weighting or summation, so that the accuracy is low. The new energy multi-station short-circuit ratio index based on capacity and voltage calculation is most suitable for analyzing the voltage support strength of a new energy multi-feed system, but is difficult to directly apply in active disconnection control. The search of the optimal section is the core of active disconnection control of the new energy power grid after destabilization, the current optimization method is a common method for searching the optimal disconnection section, and the core idea of the method is to solve the problem of active control of the optimal section search by establishing a mathematical programming model under the condition that the power grid power supply grouping result is known. However, in the practical application of the high-proportion new energy power grid, the active disconnection control method has the defects that firstly, the voltage supporting capability of the new energy power grid is not considered, the traditional active disconnection control method is difficult to meet the requirement of safe and stable operation of the high-proportion new energy power grid before and after control, secondly, the short circuit ratio index of the traditional new energy multi-station is not considered, the reactive capability of the new energy station is difficult to accurately evaluate the voltage supporting strength of the high-proportion new energy power grid, and finally, most of active control is focused on the problems of research frequency safety and the like at present, and other stability problems in the high-proportion new energy power grid are ignored. Therefore, the active control method suitable for the high-proportion new energy power grid is provided by considering the voltage support strength constraint according to the actual high-proportion new energy power grid safe operation requirement, and the active control method has important significance for safe and stable operation of the power system. Disclosure of Invention The invention aims to provide a new energy power grid active control method and device considering voltage supporting capability, so as to solve the problems in the background technology. In order to solve the technical problems, the invention provides the following technical scheme: The new energy power grid active control method considering the voltage supporting capability comprises the following steps: Step 100, based on the short-circuit capacity of the alternating current system and the equivalent grid-connected capacity of the new energy, combining reactive characteristics of the new energy station and the reactive compensation device, constructing a new energy multi-station short-circuit ratio index considering the reactive capacity; Step 200, establishing voltage support strength constraint of a new energy power grid according to the new energy multi-station short circuit ratio index, constructing a new energy bearing cap