A method and device for adjusting a non-converging cross-section of a tidal current

Abstract

The present invention relates to a method and device for adjusting a non-convergent section of power flow, including obtaining a power flow convergent section having the same power grid topology as the section to be adjusted, and determining a reference section of the section to be adjusted according to the total active power of the generating units in each power flow convergent section; correcting the reference section of the section to be adjusted; adjusting the section to be adjusted according to the node voltage, branch active power, and transmission section active power in the corrected reference section; by determining the reference section of the non-convergent section and adjusting the non-convergent section based on this reference section, the present invention eliminates the manual operation link, has a fast adjustment speed, and can effectively solve the problem of non-convergence of the section.

Description

Technical Field

[0001] The present invention relates to the technical field of power system dispatching, and in particular to a method and device for adjusting a non-convergent section of power flow. Background Art

[0002] With the construction of UHV AC / DC hybrid power grids, large-scale commissioning of new energy and DC transmission, and the increasingly significant impact of the external environment on power grid operation, the risks and uncertainties of power grid dispatching operation have increased. Pre-dispatch provides a fast and flexible means for dispatching operation personnel to perform a chronological rapid preview of the power grid. It targets the power grid operation mode and corresponding various dispatching measures for a future period of time, and helps dispatching operation personnel deepen their understanding of the power grid operation characteristics through the full-process simulation of the possible changes, evolution, and development of the power grid operation state, and improves the ability of dispatching operation personnel to perceive and handle risks.

[0003] Power flow calculation is the basis for the long-term steady-state simulation of pre-dispatch, and the convergence of power flow is the core issue related to the practicality of dispatching functions. During the pre-dispatch process, when the power grid operates in a heavy-load mode, due to the heavy load situation, a pathological power flow problem may occur, resulting in non-convergence of power flow calculation, making it impossible to calculate the power grid operation risk at the current simulation moment, and greatly reducing the practicality of the pre-dispatch function. How to solve the problem of no solution to power flow caused by the irrationality of the operation mode is an important basis for the long-term simulation of pre-dispatch.

[0004] The extended power flow calculation equations usually include equality constraints and inequality constraints. The equality constraint equation is the basic power flow equation, and the inequality constraints include node voltage constraints, line power flow constraints, etc. If there is no solution to the equality constraint, the entire power flow equation must have no solution. The traditional method to solve the problem of no solution to power flow is to make adjustments based on the experience of analysts, but this manual adjustment method has low efficiency, high work intensity, and obvious ineffectiveness. The problem of no solution to power flow is usually caused by the irrationality of the operation mode. In the case of no solution to the basic power flow equation, the power flow solution can be obtained by adjusting the generator output, improving the load power factor, and cutting off some loads, including manual adjustment strategies: reselecting the buffer machine, pre-processing the unbalanced power, and using the sensitivity method to handle the opening of the electromagnetic loop network, but the above methods cannot effectively solve the problem of non-convergence of the power flow section.

[0005] Based on the above background, there is a need in the art for a method that is fast and can effectively solve the problem of non-convergence of the section. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a method and device for adjusting a non-convergent section of power flow. By determining the reference section of the non-convergent section and adjusting the non-convergent section based on this reference section, the method of the present invention eliminates the manual operation link, has a fast adjustment speed, and can effectively solve the problem of non-convergence of the section.

[0007] The object of the present invention is achieved by the following technical solutions:

[0008] The present invention provides a method for adjusting a non-convergent section of power flow. The improvement lies in that the method includes:

[0009] Obtain a power flow convergent section with the same power grid topology as the section to be adjusted, and determine a reference section for the section to be adjusted according to the total active power of the generating units in each power flow convergent section;

[0010] Modify the reference section of the section to be adjusted;

[0011] Adjust the section to be adjusted according to the node voltage, branch active power or transmission section active power in the modified reference section.

[0012] Preferably, determining the reference section for the section to be adjusted according to the total active power of the generating units in each power flow convergent section includes:

[0013] If the difference between the total active power of the generating units in the m-th power flow convergent section and the total active power of the generating units in the section to be adjusted is the smallest, then take the m-th power flow convergent section as the reference section for the section to be adjusted;

[0014] where m ∈ [1, M], and M is the total number of the power flow convergent sections.

[0015] Preferably, modifying the reference section of the section to be adjusted includes:

[0016] Substitute the active power of each generating unit, the reactive power of each generating unit, the active power of each load, and the reactive power of each load in the reference section of the section to be adjusted into the power flow optimization model to obtain the correction amount of the active power of each generating unit, the correction amount of the reactive power of each generating unit, and the correction amount of the active power of each load in the reference section of the section to be adjusted;

[0017] Based on the correction amount of the active power of each generating unit, the correction amount of the reactive power of each generating unit, and the correction amount of the active power of each load in the reference section of the section to be adjusted, correct the active power of each generating unit, the reactive power of each generating unit, and the active power of each load in the reference section of the section to be adjusted.

[0018] Further, determine the objective function f of the power flow optimization model according to the following formula:

[0019]

[0020] In the formula, ΔP n is the correction amount of the active power of the n-th generating unit in the reference section, ΔQ nΔQ is the reactive power correction amount of the nth generator set in the reference section, ΔP d is the active power correction amount of the dth load in the reference section, N is the total number of generator sets, and D is the total number of loads;

[0021] Furthermore, the constraint conditions of the power flow optimization model include:

[0022] Active power constraint:

[0023]

[0024] In the formula, is the active power of the nth generator set in the reference section, is the active power of the dth load in the reference section, U i is the voltage amplitude of node i in the reference section, U j is the voltage amplitude of node j associated with node i in the reference section, G ij is the conductance between node i and node j in the reference section, B ij is the susceptance between node i and node j in the reference section, θ ij is the phase angle difference between node i and node j in the reference section, and J is the total number of nodes associated with node i in the reference section;

[0025] Reactive power constraint:

[0026]

[0027] In the formula, is the reactive power of the nth generator set in the reference section, is the reactive power of the dth load in the reference section, F d is the power factor of the dth load in the reference section;

[0028] Node voltage constraint:

[0029]

[0030] In the formula, is the lower limit value of the voltage amplitude of node i in the reference section, is the upper limit value of the voltage amplitude of node i in the reference section;

[0031] Branch active power constraint:

[0032]

[0033] In the formula, P ij is the branch active power between node i and node j in the reference section, The active power limit of the branch between nodes i and j in the reference section;

[0034] Active power constraint of the transmission section:

[0035]

[0036] In the formula, P sec is the active power of the transmission section in the reference section, is the active power limit of the transmission section;

[0037] Active power constraint of the generator set:

[0038]

[0039] In the formula, is the lower limit of the active power of the nth generator set in the reference section, is the upper limit of the active power of the nth generator set in the reference section;

[0040] Reactive power constraint of the generator set:

[0041]

[0042] In the formula, is the lower limit of the reactive power of the nth generator set in the reference section, is the upper limit of the reactive power of the nth generator set in the reference section;

[0043] Constraints on the active power adjustment amount of the generator set and the active power adjustment amount of the load:

[0044]

[0045] In the formula, P′ n is the active power of the nth generator set in the section to be adjusted, and P′ d is the active power of the dth load in the section to be adjusted.

[0046] Preferably, the adjustment of the section to be adjusted according to the node voltage, branch active power, and transmission section active power in the corrected reference section includes:

[0047] If the voltage of node i in the section to be adjusted is less than the voltage of node i in the corrected reference section, the active power of branch z in the section to be adjusted is greater than the active power of branch z in the corrected reference section, or the active power of the transmission section in the section to be adjusted is greater than the active power of the transmission section in the corrected reference section, then adjust the active power of each generator set according to the sensitivity of each generator set in the section to be adjusted.

[0048] Further, adjusting the active power of each generating unit according to the sensitivity of each generating unit in the section to be adjusted includes:

[0049] S1. Let a = 1;

[0050] S2. Obtain the voltage deviation of node i, the active power deviation of branch z, or the active power deviation of the transmission section ΔX;

[0051] S3. If ΔX ≠ 0 and a ≤ N, go to step S4; otherwise, the adjustment ends;

[0052] S4. Select the generating unit with the maximum sensitivity among the unadjusted generating units in the section to be adjusted as the generating unit to be adjusted, and determine the adjustment amount ΔP of the active power of the generating unit to be adjusted according to the following formula:

[0053] ΔP = ΔX / S x

[0054] In the formula, ΔX is the voltage deviation of node i, the active power deviation of branch z, or the active power deviation of the transmission section in the section to be adjusted, and S x is the sensitivity of node i in the section to be adjusted to each generating unit, the sensitivity of branch z to each generating unit, or the sensitivity of the transmission section to each generating unit;

[0055] Determine the adjusted active power P″ of the generating unit to be adjusted according to the following formula:

[0056]

[0057] In the formula, P′ max is the maximum value of the active power of the generating unit to be adjusted, and P′ is the active power of the generating unit to be adjusted before adjustment;

[0058] S5. Let a = a + 1, and return to step S2;

[0059] where N is the total number of generating units.

[0060] Based on the same inventive concept, the present invention provides a device for adjusting a section with non-convergent power flow. The improvement lies in that the device includes:

[0061] A determination unit, configured to obtain a power flow convergent section having the same power grid topology as the section to be adjusted, and determine a reference section of the section to be adjusted according to the total active power of the generating units in each power flow convergent section;

[0062] A correction unit, configured to correct the reference section of the section to be adjusted;

[0063] An adjustment unit, configured to adjust the section to be adjusted according to the node voltage, branch active power, or transmission section active power in the corrected reference section.

[0064] Preferably, the determining unit is specifically configured to:

[0065] If the difference between the total active power of the generating units in the m-th power flow convergence section and the total active power of the generating units in the section to be adjusted is the smallest, then the m-th power flow convergence section is used as the reference section of the section to be adjusted;

[0066] where m ∈ [1, M], and M is the total number of the power flow convergence sections.

[0067] Preferably, the correcting unit includes:

[0068] An obtaining module, configured to substitute the active power of each generating unit, the reactive power of each generating unit, the active power of each load, and the reactive power of each load in the reference section of the section to be adjusted into the power flow optimization model, and obtain the active power correction amount of each generating unit, the reactive power correction amount of each generating unit, and the active power correction amount of each load in the reference section of the section to be adjusted;

[0069] A correcting module, configured to correct the active power of each generating unit, the reactive power of each generating unit, and the active power of each load in the reference section of the section to be adjusted based on the active power correction amount of each generating unit, the reactive power correction amount of each generating unit, and the active power correction amount of each load in the reference section of the section to be adjusted.

[0070] Further, the objective function f of the power flow optimization model is determined by the following formula:

[0071]

[0072] In the formula, ΔP n is the active power correction amount of the n-th generating unit in the reference section, ΔQ n is the reactive power correction amount of the n-th generating unit in the reference section, ΔP d is the active power correction amount of the d-th load in the reference section, N is the total number of generating units, and D is the total number of loads;

[0073] Further, the constraint conditions of the power flow optimization model include:

[0074] Active power constraint:

[0075]

[0076] In the formula, is the active power of the n-th generating unit in the reference section, is the active power of the d-th load in the reference section, U i is the voltage amplitude of node i in the reference section, U jThe voltage magnitude of node j associated with node i in the reference section, G ij The conductance between node i and node j in the reference section, B ij The susceptance between node i and node j in the reference section, θ ij The phase angle difference between node i and node j in the reference section, and J is the total number of nodes associated with node i in the reference section;

[0077] Reactive power constraint:

[0078]

[0079] Wherein, The reactive power of the nth generator set in the reference section, The reactive power of the dth load in the reference section, F d The power factor of the dth load in the reference section;

[0080] Node voltage constraint:

[0081]

[0082] Wherein, The lower limit value of the voltage magnitude of node i in the reference section, The upper limit value of the voltage magnitude of node i in the reference section;

[0083] Branch active power constraint:

[0084]

[0085] Wherein, P ij The branch active power between node i and node j in the reference section, The branch active power limit value between node i and node j in the reference section;

[0086] Transmission section active power constraint:

[0087]

[0088] Wherein, P sec The transmission section active power in the reference section, The transmission section active power limit value;

[0089] Generator set active power constraint:

[0090]

[0091] Wherein, The lower limit value of the active power of the nth generator set in the reference section, is the upper limit of the active power of the nth generator set in the reference section;

[0092] Reactive power constraint of the generator set:

[0093]

[0094] In the formula, is the lower limit of the reactive power of the nth generator set in the reference section, is the upper limit of the reactive power of the nth generator set in the reference section;

[0095] Constraints on the active power adjustment amount of the generator set and the active power adjustment amount of the load:

[0096]

[0097] In the formula, P′ n is the active power of the nth generator set in the section to be adjusted, P′ d is the active power of the dth load in the section to be adjusted.

[0098] Preferably, the adjustment unit is specifically configured to:

[0099] If the voltage of node i in the section to be adjusted is less than the voltage of node i in the corrected reference section, the active power of branch z in the section to be adjusted is greater than the active power of branch z in the corrected reference section, or the active power of the transmission section in the section to be adjusted is greater than the active power of the transmission section in the corrected reference section, then adjust the active power of each generator set according to the sensitivity of each generator set in the section to be adjusted.

[0100] Further, the adjustment module is specifically configured to:

[0101] S1. Let a = 1;

[0102] S2. Obtain the voltage deviation of node i, the active power deviation of branch z, or the active power deviation ΔX of the transmission section;

[0103] S3. If ΔX ≠ 0 and a ≤ N, then go to step S4, otherwise the adjustment ends;

[0104] S4. Select the generator set with the largest sensitivity among the unadjusted generator sets in the section to be adjusted as the generator set to be adjusted, and determine the adjustment amount ΔP of the active power of the generator set to be adjusted according to the following formula:

[0105] ΔP = ΔX / S x

[0106] In the formula, ΔX is the voltage deviation of node i, the active power deviation of branch z, or the active power deviation of the transmission section in the section to be adjusted, S xis the sensitivity of node i in the section to be adjusted to each generator set, the sensitivity of branch z to each generator set, or the sensitivity of the transmission section to each generator set;

[0107] Determine the adjusted active power P″ of the generator set to be adjusted according to the following formula:

[0108]

[0109] In the formula, P′ max is the maximum value of the active power of the generator set to be adjusted, and P′ is the active power of the generator set to be adjusted before adjustment;

[0110] S5. Let a = a + 1, and return to step S2;

[0111] where N is the total number of generator sets.

[0112] Compared with the closest prior art, the beneficial effects of the present invention are:

[0113] A power flow non-convergent section adjustment method and device provided by the present invention include obtaining a power flow convergent section with the same power grid topology as the section to be adjusted, and determining a reference section of the section to be adjusted according to the total active power of the generator sets in each power flow convergent section; correcting the reference section of the section to be adjusted; adjusting the section to be adjusted according to the node voltage, branch active power, and transmission section active power in the corrected reference section; the present invention solves the problems of low efficiency, high working intensity, and unclear effect of the prior art method of manually solving the power flow without solution by determining the reference section of the non-convergent section and adjusting the non-convergent section based on this reference section; among them, using a pre-established power flow optimization model to correct the reference section makes the subsequent adjustment process more in line with the actual situation and can effectively solve the problem of section non-convergence. Brief Description of the Drawings

[0114] Figure 1 is a flowchart of the power flow non-convergent section adjustment method of the present invention;

[0115] Figure 2 is a schematic diagram of the power flow non-convergent section adjustment device of the present invention. Detailed Description of the Embodiment

[0116] The following further details the specific embodiments of the present invention in conjunction with the drawings.

[0117] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0118] The present invention provides a method for adjusting a power flow non-convergent section. As Figure 1 shown, the method includes:

[0119] Step S101: Obtain a power flow convergent section having the same power grid topology as the section to be adjusted, and determine a reference section for the section to be adjusted according to the total active power of the generating units in each power flow convergent section;

[0120] Step S102: Correct the reference section of the section to be adjusted;

[0121] Step S103: Adjust the section to be adjusted according to the node voltages, branch active powers, and transmission section active powers in the corrected reference section.

[0122] To more clearly illustrate the objectives of the present invention, the method of the present invention will be described in detail through the following embodiments.

[0123] In the embodiments of the present invention, in step S101, a power flow convergent section having the same power grid topology as the section to be adjusted can be obtained through the prior art known to those skilled in the art, or can also be obtained through the following method:

[0124] Step 1) Power grid section set generation

[0125] According to the dispatching rehearsal period and rehearsal time multiple, continuously extract the power grid operation sections during the pre-dispatch simulation in chronological order, perform topology analysis on each section using the depth-first search algorithm, and select sections with the same topology to generate a section set S = {S1, S2,..., S i ,..., S A}, where S i is the i-th element of the set S, i is the total number of sections, and i ∈ [1, A].

[0126] Step 2) Section set classification

[0127] Traverse the section set S, read the unanalyzed section S i and perform a power flow calculation. Use the convergence flag bit output by the power flow calculation to judge S iWhether the cross-section current converges, the cross-sections with convergent current form a convergent cross-section set T, and the cross-sections with non-convergent current form a non-convergent cross-section set U.

[0128] Among them, T = {T1, T2,..., T b ,..., T B}, U = {U1, U2,..., U c ,..., U C}, B is the total number of non-convergent cross-sections, C is the total number of convergent cross-sections, and the number of cross-sections satisfies A = B + C.

[0129] Step 3) Each cross-section in the non-convergent cross-section set U is used as the cross-section to be adjusted.

[0130] In the embodiment of the present invention, the step of determining the reference cross-section of the cross-section to be adjusted according to the total active power of the generator sets in each current-convergent cross-section in step S101 may include the following steps:

[0131] If the difference between the total active power of the generator sets in the m-th current-convergent cross-section and the total active power of the generator sets in the cross-section to be adjusted is the smallest, then the m-th current-convergent cross-section is used as the reference cross-section of the cross-section to be adjusted;

[0132] Among them, m ∈ [1, M], and M is the total number of the current-convergent cross-sections.

[0133] In the embodiment of the present invention, step S102 may include the following steps:

[0134] Substitute the active power of each generator set, the reactive power of each generator set, the active power of each load, and the reactive power of each load in the reference cross-section of the cross-section to be adjusted into the power flow optimization model to obtain the correction amount of the active power of each generator set, the correction amount of the reactive power of each generator set, and the correction amount of the active power of each load in the reference cross-section of the cross-section to be adjusted;

[0135] Based on the correction amount of the active power of each generator set, the correction amount of the reactive power of each generator set, and the correction amount of the active power of each load in the reference cross-section of the cross-section to be adjusted, correct the active power of each generator set, the reactive power of each generator set, and the active power of each load in the reference cross-section of the cross-section to be adjusted.

[0136] Specifically, the objective function f of the power flow optimization model is determined according to the following formula:

[0137]

[0138] In the formula, ΔP n is the correction amount of the active power of the n-th generator set in the reference cross-section, ΔQ n is the correction amount of the reactive power of the n-th generator set in the reference cross-section, ΔPd The active power correction amount of the d-th load in the reference section, N is the total number of generating units, and D is the total number of loads;

[0139] Specifically, the constraint conditions of the above power flow optimization model include:

[0140] Active power constraint:

[0141]

[0142] In the formula, is the active power of the n-th generating unit in the reference section, is the active power of the d-th load in the reference section, U i is the voltage amplitude of node i in the reference section, U j is the voltage amplitude of node j associated with node i in the reference section, G ij is the conductance between node i and node j in the reference section, B ij is the susceptance between node i and node j in the reference section, θ ij is the phase angle difference between node i and node j in the reference section, and J is the total number of nodes associated with node i in the reference section;

[0143] Reactive power constraint:

[0144]

[0145] In the formula, is the reactive power of the n-th generating unit in the reference section, is the reactive power of the d-th load in the reference section, F d is the power factor of the d-th load in the reference section;

[0146] Node voltage constraint:

[0147]

[0148] In the formula, is the lower limit value of the voltage amplitude of node i in the reference section, is the upper limit value of the voltage amplitude of node i in the reference section;

[0149] Branch active power constraint:

[0150]

[0151] In the formula, P ij is the branch active power between node i and node j in the reference section, is the branch active power limit value between node i and node j in the reference section;

[0152] Active power constraint of transmission section:

[0153]

[0154] In the formula, P sec is the active power of the transmission section in the reference section, is the limit value of the active power of the transmission section;

[0155] Active power constraint of generating units:

[0156]

[0157] In the formula, is the lower limit value of the active power of the nth generating unit in the reference section, is the upper limit value of the active power of the nth generating unit in the reference section;

[0158] Reactive power constraint of generating units:

[0159]

[0160] In the formula, is the lower limit value of the reactive power of the nth generating unit in the reference section, is the upper limit value of the reactive power of the nth generating unit in the reference section;

[0161] Constraints on the active power adjustment amount of generating units and the active power adjustment amount of loads:

[0162]

[0163] In the formula, P′ n is the active power of the nth generating unit in the section to be adjusted, and P′ d is the active power of the dth load in the section to be adjusted.

[0164] In the embodiment of the present invention, step S103 may include the following steps:

[0165] If the voltage of node i in the section to be adjusted is less than the voltage of node i in the corrected reference section, the active power of branch z in the section to be adjusted is greater than the active power of branch z in the corrected reference section, or the active power of the transmission section in the section to be adjusted is greater than the active power of the transmission section in the corrected reference section, then adjust the active power of each generating unit according to the sensitivity of each generating unit in the section to be adjusted.

[0166] The nodes in the above solution include generating units, loads, and other network nodes. The branch is the line between any two nodes. The non-convergent section includes several transmission sections divided by the upper-layer dispatching center according to the actual working conditions.

[0167] Specifically, adjusting the active power of each generating unit according to the sensitivity of each generating unit in the section to be adjusted includes:

[0168] S1. Let a = 1;

[0169] S2. Obtain the voltage deviation of node i, the active power deviation of branch z or the active power deviation ΔX of the transmission section;

[0170] S3. If ΔX≠0 and a≤N, go to step S4, otherwise the adjustment ends;

[0171] S4. Select the generating unit with the highest sensitivity among the unadjusted generating units in the section to be adjusted as the generating unit to be adjusted, and determine the adjustment amount ΔP of the active power of the generating unit to be adjusted according to the following formula:

[0172] ΔP = ΔX / S x

[0173] In the formula, ΔX is the voltage deviation of node i, the active power deviation of branch z or the active power deviation of the transmission section in the section to be adjusted, and S x is the sensitivity of node i in the section to be adjusted to each generating unit, the sensitivity of branch z to each generating unit or the sensitivity of the transmission section to each generating unit;

[0174] Determine the adjusted active power P″ of the generating unit to be adjusted according to the following formula:

[0175]

[0176] In the formula, P′ max is the maximum value of the active power of the generating unit to be adjusted, and P′ is the active power of the generating unit to be adjusted before adjustment;

[0177] S5. Let a = a + 1, and return to step S2;

[0178] Wherein, N is the total number of generating units.

[0179] Based on the same inventive concept, the present invention provides a device for adjusting a non-convergent power flow section, as Figure 2 shown, the device includes:

[0180] A determination unit, configured to obtain a power flow convergent section having the same power grid topology as the section to be adjusted, and determine a reference section of the section to be adjusted according to the total active power of the generating units in each power flow convergent section;

[0181] A correction unit, configured to correct the reference section of the section to be adjusted;

[0182] An adjustment unit for adjusting the section to be adjusted according to the node voltages, branch active powers, and transmission section active powers in the corrected reference section.

[0183] In an embodiment of the present invention, the above-mentioned determination unit is specifically configured to:

[0184] If the difference between the total active power of the generating units in the m-th power flow convergence section and the total active power of the generating units in the section to be adjusted is the smallest, then the m-th power flow convergence section is used as the reference section of the section to be adjusted;

[0185] where m ∈ [1, M], and M is the total number of the power flow convergence sections.

[0186] In an embodiment of the present invention, the above-mentioned correction unit includes:

[0187] An acquisition module for substituting the active powers of each generating unit, the reactive powers of each generating unit, the active powers of each load, and the reactive powers of each load in the reference section of the section to be adjusted into a power flow optimization model to obtain the active power correction amount of each generating unit, the reactive power correction amount of each generating unit, and the active power correction amount of each load in the reference section of the section to be adjusted;

[0188] A correction module for correcting the active powers of each generating unit, the reactive powers of each generating unit, and the active powers of each load in the reference section of the section to be adjusted based on the active power correction amount of each generating unit, the reactive power correction amount of each generating unit, and the active power correction amount of each load in the reference section of the section to be adjusted.

[0189] In an embodiment of the present invention, the interior point method is used to solve the power flow optimization model, which improves the accuracy of the solution result and the convergence of the non-convergent section after adjustment;

[0190] Specifically, the objective function f of the power flow optimization model is determined according to the following formula:

[0191]

[0192] In the formula, ΔP n is the active power correction amount of the n-th generating unit in the reference section, ΔQ n is the reactive power correction amount of the n-th generating unit in the reference section, ΔP d is the active power correction amount of the d-th load in the reference section, N is the total number of generating units, and D is the total number of loads;

[0193] Specifically, the constraint conditions of the above-mentioned power flow optimization model include:

[0194] Active power constraint:

[0195]

[0196] Wherein, is the active power of the nth generator set in the reference section, is the active power of the dth load in the reference section, U i is the voltage amplitude of node i in the reference section, U j is the voltage amplitude of node j associated with node i in the reference section, G ij is the conductance between node i and node j in the reference section, B ij is the susceptance between node i and node j in the reference section, θ ij is the phase angle difference between node i and node j in the reference section; J is the total number of nodes associated with node i in the reference section;

[0197] Reactive power constraint:

[0198]

[0199] Wherein, is the reactive power of the nth generator set in the reference section, is the reactive power of the dth load in the reference section, F d is the power factor of the dth load in the reference section;

[0200] Node voltage constraint:

[0201]

[0202] Wherein, is the lower limit value of the voltage amplitude of node i in the reference section, is the upper limit value of the voltage amplitude of node i in the reference section;

[0203] Branch active power constraint:

[0204]

[0205] Wherein, P ij is the branch active power between node i and node j in the reference section, is the branch active power limit value between node i and node j in the reference section;

[0206] Transmission section active power constraint:

[0207]

[0208] Wherein, P sec is the transmission section active power in the reference section, is the transmission section active power limit value;

[0209] Active power constraint of the generator set:

[0210]

[0211] Wherein, is the lower limit value of the active power of the nth generator set in the reference section, is the upper limit value of the active power of the nth generator set in the reference section;

[0212] Reactive power constraint of the generator set:

[0213]

[0214] Wherein, is the lower limit value of the reactive power of the nth generator set in the reference section, is the upper limit value of the reactive power of the nth generator set in the reference section;

[0215] Constraints on the active power adjustment amount of the generator set and the active power adjustment amount of the load:

[0216]

[0217] Wherein, P′ n is the active power of the nth generator set in the section to be adjusted, and P′ d is the active power of the dth load in the section to be adjusted.

[0218] In the embodiment of the present invention, the above adjustment unit is specifically used for:

[0219] If the voltage of node i in the section to be adjusted is less than the voltage of node i in the corrected reference section, the active power of branch z in the section to be adjusted is greater than the active power of branch z in the corrected reference section, or the active power of the transmission section in the section to be adjusted is greater than the active power of the transmission section in the corrected reference section, then adjust the active power of each generator set according to the sensitivity of each generator set in the section to be adjusted.

[0220] Specifically, the above adjustment module is specifically used for:

[0221] S1. Let a = 1;

[0222] S2. Obtain the voltage deviation of node i, the active power deviation of branch z, or the active power deviation ΔX of the transmission section;

[0223] S3. If ΔX ≠ 0 and a ≤ N, then go to step S4, otherwise the adjustment ends;

[0224] S4. Select the generating unit with the maximum sensitivity among the unadjusted generating units in the section to be adjusted as the generating unit to be adjusted, and determine the adjustment amount ΔP of the active power of the generating unit to be adjusted according to the following formula:

[0225] ΔP = ΔX / S x

[0226] In the formula, ΔX is the voltage deviation of node i, the active power deviation of branch z, or the active power deviation of the transmission section in the section to be adjusted, and S x is the sensitivity of node i to each generating unit, the sensitivity of branch z to each generating unit, or the sensitivity of the transmission section to each generating unit in the section to be adjusted;

[0227] Determine the adjusted active power P″ of the generating unit to be adjusted according to the following formula:

[0228]

[0229] In the formula, P′ max is the maximum value of the active power of the generating unit to be adjusted, and P′ is the active power of the generating unit to be adjusted before adjustment;

[0230] S5. Let a = a + 1, and return to step S2;

[0231] where N is the total number of generating units.

[0232] In summary, a power flow non-convergent section adjustment method and device provided by the present invention include obtaining a power flow convergent section with the same power grid topology as the section to be adjusted, and determining a reference section of the section to be adjusted according to the total active power of the generating units in each power flow convergent section; correcting the reference section of the section to be adjusted; adjusting the section to be adjusted according to the node voltage, branch active power, and transmission section active power in the corrected reference section; the present invention solves the problems of low efficiency, high working intensity, and unclear effect of the existing manual method for solving the power flow without solution by determining the reference section of the non-convergent section and adjusting the non-convergent section based on the reference section; among them, the reference section is corrected by using a pre-established power flow optimization model, making the subsequent adjustment process more in line with the actual situation, and effectively solving the problem of section non-convergence.

[0233] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented 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.

[0234] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate means for implementing the specified functions in one or more flows Figure 1 one or more flows and / or blocks Figure 1 or in one or more blocks.

[0235] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implements the specified functions in one or more flows Figure 1 one or more flows and / or blocks Figure 1 or in one or more blocks.

[0236] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the specified functions in one or more flows Figure 1 one or more flows and / or blocks Figure 1 or in one or more blocks.

[0237] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific implementation manners of the present invention, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A method for adjusting the cross-section of a non-converging tidal current, characterized in that, The method includes: Obtaining a power flow convergence section with the same power grid topology as the section to be adjusted, and determining a reference section of the section to be adjusted according to the total active power of the generating units in each power flow convergence section; Correcting the reference section of the section to be adjusted; Adjusting the section to be adjusted according to the node voltage, branch active power or transmission section active power in the corrected reference section; The determining the reference section of the section to be adjusted according to the total active power of the generating units in each power flow convergence section includes: If the difference between the total active power of the generating units in the m-th power flow convergence section and the total active power of the generating units in the section to be adjusted is the smallest, then taking the m-th power flow convergence section as the reference section of the section to be adjusted; Among them, , M is the total number of the tidal current convergence cross-sections; The correcting the reference section of the section to be adjusted includes: Substituting the active power of each generating unit, the reactive power of each generating unit, the active power of each load, and the reactive power of each load in the reference section of the section to be adjusted into the power flow optimization model to obtain the correction amount of the active power of each generating unit, the correction amount of the reactive power of each generating unit, and the correction amount of the active power of each load in the reference section of the section to be adjusted; Based on the correction amount of the active power of each generating unit, the correction amount of the reactive power of each generating unit, and the correction amount of the active power of each load in the reference section of the section to be adjusted, correcting the active power of each generating unit, the reactive power of each generating unit, and the active power of each load in the reference section of the section to be adjusted; Determine the objective function of the power flow optimization model according to the following formula : In the formula, is the active power correction amount of the nth generator set in the reference section, is the reactive power correction amount of the nth generator set in the reference section, is the active power correction amount of the dth load in the reference section, N is the total number of generator sets, and D is the total number of loads.

2. The method according to claim 1, wherein The constraint conditions of the power flow optimization model include: Active power constraint: Wherein, is the active power of the nth generator set in the reference section, is the active power of the dth load in the reference section, is the voltage amplitude of node i in the reference section, is the voltage amplitude of node j associated with node i in the reference section, is the conductance between node i and node j in the reference section, is the susceptance between node i and node j in the reference section, is the phase angle difference between node i and node j in the reference section, and J is the total number of nodes associated with node i in the reference section; Reactive power constraint: In the formula, is the reactive power of the nth generating unit in the reference section, is the reactive power of the dth load in the reference section, is the power factor of the dth load in the reference section; Node voltage constraint: wherein, is the lower limit of the voltage amplitude of node i in the reference section, is the upper limit of the voltage amplitude of node i in the reference section; Branch active power constraint: In the formula, is the active power of the branch between node i and node j in the reference section, is the limit value of the active power of the branch between node i and node j in the reference section; Transmission section active power constraint: Wherein, is the active power of the transmission section in the reference section, is the limit value of the active power of the transmission section; Generating unit active power constraint: Wherein, is the lower limit value of the active power of the nth generating unit in the reference section, is the upper limit value of the active power of the nth generating unit in the reference section; Generating unit reactive power constraint: In the formula, is the lower limit of the reactive power of the nth generator set in the reference section, is the upper limit of the reactive power of the nth generator set in the reference section; Generating unit active power regulation amount and load active power regulation amount constraint: In the formula, is the active power of the nth generator set in the section to be adjusted, is the active power of the dth load in the section to be adjusted.

3. The method according to claim 1, wherein The adjusting the section to be adjusted according to the node voltage, branch active power or transmission section active power in the corrected reference section includes: If the voltage of node i in the section to be adjusted is less than the voltage of node i in the corrected reference section, the active power of branch z in the section to be adjusted is greater than the active power of branch z in the corrected reference section, or the transmission section active power in the section to be adjusted is greater than the transmission section active power in the corrected reference section, then adjusting the active power of each generating unit according to the sensitivity of each generating unit in the section to be adjusted.

4. The method according to claim 3, wherein The adjusting the active power of each generating unit according to the sensitivity of each generating unit in the section to be adjusted includes: S1. Let a = 1; S2. Obtain the voltage deviation of node i, the active power deviation of branch z, or the active power deviation of the transmission section ; S3. If and , go to step S4; otherwise, end the adjustment. S4. Select the generating unit with the maximum sensitivity among the unadjusted generating units in the section to be adjusted as the generating unit to be adjusted, and determine the adjustment amount of the active power of the generating unit to be adjusted according to the following formula : Wherein, is the voltage deviation of node i, the active power deviation of branch z, or the active power deviation of the transmission section in the section to be adjusted; is the sensitivity of node i in the section to be adjusted to each generator set, the sensitivity of branch z to each generator set, or the sensitivity of the transmission section to each generator set; Determine the adjusted active power of the generator set to be adjusted according to the following formula : In the formula, is the maximum value of the active power of the generator set to be adjusted, is the active power of the generator set to be adjusted before adjustment; S5. Let a = a + 1, and return to step S2; Where N is the total number of generating units.

5. A cross-section adjustment device for non-converging flow, characterized in that, The device includes: A determination unit, configured to obtain a power flow convergence section with the same power grid topology as the section to be adjusted, and determine a reference section of the section to be adjusted according to the total active power of the generating units in each power flow convergence section; A correction unit, configured to correct the reference section of the section to be adjusted; An adjustment unit, configured to adjust the section to be adjusted according to the node voltage, branch active power or transmission section active power in the corrected reference section; The determination unit is specifically configured to: If the difference between the total active power of the generating units in the m-th power flow convergence section and the total active power of the generating units in the section to be adjusted is the smallest, then the m-th power flow convergence section is used as the reference section of the section to be adjusted; Among them, , M is the total number of the tidal current convergence cross-sections; The correction unit includes: An acquisition module, configured to substitute the active power of each generating unit, the reactive power of each generating unit, the active power of each load, and the reactive power of each load in the reference section of the section to be adjusted into a power flow optimization model, and obtain the active power correction amount of each generating unit, the reactive power correction amount of each generating unit, and the active power correction amount of each load in the reference section of the section to be adjusted; A correction module, configured to correct the active power of each generating unit, the reactive power of each generating unit, and the active power of each load in the reference section of the section to be adjusted based on the active power correction amount of each generating unit, the reactive power correction amount of each generating unit, and the active power correction amount of each load in the reference section of the section to be adjusted; Determine the objective function of the power flow optimization model according to the following formula : In the formula, is the active power correction amount of the nth generator set in the reference section, is the reactive power correction amount of the nth generator set in the reference section, is the active power correction amount of the dth load in the reference section, N is the total number of generator sets, and D is the total number of loads.

6. The device according to claim 5, wherein The adjustment unit is specifically configured to: If the voltage of node i in the section to be adjusted is less than the voltage of node i in the corrected reference section, the active power of branch z in the section to be adjusted is greater than the active power of branch z in the corrected reference section, or the active power of the transmission section in the section to be adjusted is greater than the active power of the transmission section in the corrected reference section, then adjust the active power of each generating unit according to the sensitivity of each generating unit in the section to be adjusted.

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