Generator leading phase capability analysis method and system based on power grid transient stability constraint

Abstract

The application discloses a kind of generator phase-advancing capability analysis method and system based on power grid transient stability constraint, comprising the following steps: according to power grid system stability and converter station bus voltage control condition obtains single machine maximum phase-advancing depth;According to single machine maximum phase-advancing depth, obtain the phase-advancing depth of power plant and the phase-advancing depth reserved by whole plant.This application mainly aims at the problem that the regulation range of other regulating means such as shunt reactor is limited when voltage is too high due to excessive reactive power, fully considers factors such as stator end heating and power angle static stability, determines single machine maximum phase-advancing depth, considers the most serious situation of overvoltage of DC converter station, determines the phase-advancing capability of power plant and the phase-advancing capability reserved by whole plant after DC fault tripping based on whether steady-state overvoltage exceeds voltage limit, fully develops the voltage regulating capability of generator, so as to more economically and efficiently ensure the stable operation of power grid voltage.

Description

TECHNICAL FIELD

[0001] The application relates to a generator leading-phase capability analysis method and system based on power grid transient stability constraints and belongs to the technical field of power system operation control. BACKGROUND

[0002] Voltage is related to the safe and stable operation of a power grid and is one of important indicators of power quality. Nowadays, voltage safety is paid more attention to, and voltage safety problems are faced with more severe challenges in the face of new situations of power source structure and power grid structure changes.

[0003] With the increasing proportion of new energy power generation, the system inertia continues to decrease, and the randomness and uncertainty of new energy power generation affect the system, resulting in large day-night changes in power flow, thus causing large voltage fluctuations of the power grid and seriously affecting the frequency disturbance resistance of the system. The topology structure and power fluctuation characteristics of the new energy station with a high proportion determine that the voltage fluctuation range of the power grid is large, and a large number of dynamic reactive power compensation devices are dispersedly arranged in the power grid. When the system fails, the new energy unit enters low penetration due to the grid protection, and the dynamic reactive power device may provide too much reactive power to cause overvoltage problems during recovery. In addition, under the condition of large-scale generator tripping due to DC blocking, the near-zone power flow will be greatly reduced, which may cause steady-state overvoltage of the power grid equipment and threaten the safety of the equipment. Using other regulating means such as shunt reactors not only consumes a large amount of capital and increases the occupied area, but also has a limited regulating range. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a generator leading-phase capability analysis method and system based on power grid transient stability constraints to solve the problem of difficult system voltage regulation in the prior art.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] A generator leading-phase capability analysis method, comprising the following steps:

[0007] obtaining a single-machine maximum leading-phase depth according to the stability of the power grid system and the bus voltage control state of the converter station;

[0008] obtaining a whole-plant leading-phase depth and a whole-plant reserved leading-phase depth of the power plant according to the single-machine maximum leading-phase depth.

[0009] Further, the process of obtaining the single-machine maximum leading-phase depth is as follows:

[0010] Let the initial value of the single-machine maximum leading-phase depth be zero;

[0011] a. judging whether the power grid system is stable according to the determined fault set;

[0012] b. If the power grid system is stable, determine whether the converter station bus voltage is within the control range, otherwise increase the converter station bus voltage and return to step a;

[0013] c. If the converter station bus voltage is within the control range, increase the single-machine maximum phase advance depth and return to step a; otherwise output the single-machine maximum phase advance depth.

[0014] Further, the process of obtaining the power plant overall phase advance depth and the overall reserved phase advance depth is as follows:

[0015] Let the initial value of the power plant overall phase advance depth be the single-machine maximum phase advance depth;

[0016] a. Determine whether the power grid system is stable according to the determined fault set, if the power grid system is not stable, reduce the power plant overall phase advance depth and go to step d, if the power grid system is stable, go to step b;

[0017] b. Determine whether the steady-state voltage after DC fault exceeds the voltage limit, if not, go to step c, if yes, go to step d;

[0018] c. Increase the power plant overall phase advance depth and return to step a;

[0019] d. Increase the overall reserved phase advance depth and go to step e;

[0020] e. Determine whether the overall reserved phase advance depth is less than the single-machine maximum phase advance depth, if yes, go to step f;

[0021] f. Determine whether the steady-state voltage after DC fault exceeds the voltage limit, if the steady-state overvoltage does not exceed the voltage limit, output the power plant overall phase advance depth and the overall reserved phase advance depth.

[0022] Further, the value range of the overall reserved phase advance depth is:

[0023] Q t -min[Q t ,(M-1) Q s ]≤Q l ≤Q s ,

[0024] Wherein, Q l is the overall reserved phase advance depth, Q t is the power plant overall phase advance depth, Q s is the single-machine maximum phase advance depth, and M is

[0025] Further, the initial value of the overall reserved phase advance depth is the overall reserved phase advance depth when the power plant only reserves one machine after the DC fault blocking and machine tripping.

[0026] Furthermore, the fault set includes the first, second, and third-level DC transmission sections, the outgoing sections of the leading-phase power plants, and the critical sections of the power grid system.

[0027] A generator phase-leading capability analysis system, the system comprising:

[0028] First acquisition module: used to obtain the maximum phase advance depth of a single unit based on the stability of the power grid system and the voltage control status of the converter station bus;

[0029] The second acquisition module is used to acquire the total phase advance depth and the total retained phase advance depth of the power plant based on the maximum phase advance depth of a single unit.

[0030] A generator phase advance capability analysis system, the system comprising a processor and a storage medium;

[0031] The storage medium is used to store instructions;

[0032] The processor is configured to operate according to the instructions to execute the steps of the method described above.

[0033] A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of the method described above.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] This invention takes into account the transient stability constraints of the large power grid to determine the maximum phase advance depth of a single unit, the phase advance capability of the entire power plant, and the phase advance capability retained by the entire plant after a DC fault trip. This allows for a more comprehensive, full, and flexible utilization of the voltage regulation capability of the entire power plant's generators, eliminating the operational risk of grid voltage instability caused by the limited adjustment range of other regulation methods such as parallel reactors. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating a specific implementation of the present invention. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0038] like Figure 1 As shown, a method for analyzing the leading phase capability of generators based on power grid transient stability constraints includes the following steps:

[0039] Assume the total phase advance depth of the power plant is Q. t 10,000 kilowatts, single unit phase advance depth is Q s 10,000 kW, after a DC fault trip, the entire plant retains the leading phase Q. lMW, the converter station bus voltage is V.

[0040] Step 1: Obtain the single-machine maximum phase advance according to the power grid system stability and the converter station bus voltage control condition, specifically as follows:

[0041] Set the initial value of the single-machine maximum phase advance Q s to zero,

[0042] a. Determine whether the power grid system is stable according to the fault set (the first, second and third level of DC transmission section, the phase-advancing power plant sending section, the system key section, etc. N-1, N-2 fault);

[0043] b. If the power grid system is stable, determine whether the converter station bus voltage is within the control requirement range, otherwise increase the converter station bus voltage and return to step a;

[0044] c. If the converter station bus voltage is within the control range, increase the single-machine maximum phase advance and return to step a; otherwise, output the single-machine maximum phase advance restricted by the system transient stability.

[0045] Step 2: Obtain the power plant total plant phase advance and the total plant reserved phase advance according to the single-machine maximum phase advance, specifically as follows:

[0046] Set the initial value of the power plant total plant phase advance Q t to the single-machine maximum phase advance Q s ;

[0047] a. Check the stability of the system according to the set fault set, if the system is unstable due to a fault, reduce the power plant total plant phase advance and go to step d; if there is no fault in the fault set that causes the system to be unstable, go to step b.

[0048] b. Determine whether the steady-state voltage after DC fault exceeds the voltage limit, if not, go to step c, if yes, go to step d;

[0049] c. Increase the power plant total plant phase advance and return to step a;

[0050] d. Increase the total plant reserved phase advance and go to step e;

[0051] e. Determine whether the total plant reserved phase advance is less than the single-machine maximum phase advance, if yes, go to step f;

[0052] f. Calculate the overvoltage level of the converter station after DC blocking, if the steady-state overvoltage does not exceed the voltage limit, then the power plant total plant phase advance Q t and the total plant reserved phase advance Q l are a set of solutions that satisfy the conditions, output Q t , Ql .

[0053] The value range of the whole plant reserved phase advancing depth is:

[0054] Q t -min[Q t ,(M-1) Q s ]≤Q l ≤Q s ,

[0055] Wherein, Q l is the whole plant reserved phase advancing depth, Q t is the whole plant phase advancing depth of the power plant, Q s is the maximum phase advancing depth of a single machine, and M is the number of units in the whole plant.

[0056] The initial value of the whole plant reserved phase advancing depth is the whole plant reserved phase advancing depth when the power plant only reserves one machine after the DC fault blocking machine is cut off.

[0057] In view of the problem that the regulation range of other regulation means such as shunt reactors is limited due to excessive reactive power leading to high voltage, the power generator set phase advancing operation is used to absorb the excess reactive power of the system, so that the system voltage can be maintained within the specified range, which is an economic, effective and feasible method. The voltage regulation method using the generator set phase advancing operation does not need to add additional equipment, fully utilizes the voltage regulation capacity of the generator set itself, and only needs to determine the phase advancing depth of the generator through theoretical calculation and field test. The maximum phase advancing depth of a single machine is determined by fully considering the stator end heating, power angle static stability and other factors, the whole plant phase advancing capacity of the power plant and the whole plant reserved phase advancing capacity after the DC fault machine is cut off are determined based on whether the steady-state overvoltage exceeds the voltage limit, the voltage regulation capacity of the generator is fully utilized, so that it is of great significance to more economically and efficiently ensure the stable operation of the power grid voltage.

[0058] A generator phase advancing capacity analysis system, the system comprises:

[0059] The first acquisition module is used to acquire the maximum phase advancing depth of a single machine according to the stability of the power grid system and the control condition of the bus voltage of the converter station;

[0060] The second acquisition module is used to acquire the whole plant phase advancing depth of the power plant and the whole plant reserved phase advancing depth according to the maximum phase advancing depth of a single machine.

[0061] A generator phase advancing capacity analysis system, the system comprises a processor and a storage medium;

[0062] The storage medium is used to store instructions;

[0063] The processor is used to operate according to the instructions to perform the steps of the above-mentioned method.

[0064] A computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the above-described method.

[0065] The present application is described with reference to the flowchart and / or block diagram illustrations of the methods, apparatus (systems) and computer program products according to embodiments of the present application. It will be understood that each block of the flowchart and / or block diagrams, and combinations of blocks in the flowchart 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, create means for implementing the functions specified in the flowchart and / or block diagram block or blocks. Figure 1 The flowchart and / or block diagrams can also be implemented by computer readable instructions residing on a computer readable storage medium having computer readable instructions executing on a computer such that the computer implemented processes specify the functions described by such flowchart and / or block diagrams. Figure 1 The flowchart and / or block diagrams can also be implemented by computer readable instructions residing on a computer readable storage medium having computer readable instructions executing on a computer such that the computer implemented processes specify the functions described by such flowchart and / or block diagrams.

[0066] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the flowchart and / or block diagram block or blocks. Figure 1 The flowchart and / or block diagrams can also be implemented by computer readable instructions residing on a computer readable storage medium having computer readable instructions executing on a computer such that the computer implemented processes specify the functions described by such flowchart and / or block diagrams. Figure 1 The flowchart and / or block diagrams can also be implemented by computer readable instructions residing on a computer readable storage medium having computer readable instructions executing on a computer such that the computer implemented processes specify the functions described by such flowchart and / or block diagrams.

[0067] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flowchart and / or block diagram block or blocks. Figure 1 The flowchart and / or block diagrams can also be implemented by computer readable instructions residing on a computer readable storage medium having computer readable instructions executing on a computer such that the computer implemented processes specify the functions described by such flowchart and / or block diagrams. Figure 1 The flowchart and / or block diagrams can also be implemented by computer readable instructions residing on a computer readable storage medium having computer readable instructions executing on a computer such that the computer implemented processes specify the functions described by such flowchart and / or block diagrams.

[0068] The above merely provides an embodiment of the present application, but is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the scope of claims of the present application.

Claims

1. A method for analyzing the leading phase capability of a generator, characterized in that, Includes the following steps: The maximum phase advance depth of a single unit is obtained based on the stability of the power grid system and the voltage control status of the converter station bus. The total advance depth of the power plant and the retained advance depth of the power plant are obtained based on the maximum advance depth of a single unit. The process for obtaining the maximum advance depth of a single machine is as follows: Set the initial value of the maximum advance depth of a single unit to zero; a. Determine whether the power grid system is stable based on the identified fault set; b. If the power grid system is stable, determine whether the converter station bus voltage is within the control range; otherwise, increase the converter station bus voltage and return to step a. c. If the converter station bus voltage is within the control range, increase the maximum phase advance depth of a single unit and return to step a; otherwise, output the maximum phase advance depth of a single unit. The process for obtaining the overall advanced phase depth and the overall retained advanced phase depth of the power plant is as follows: Let the initial value of the total phase advance depth of the power plant be the maximum phase advance depth of a single unit; a. Determine whether the power grid system is stable based on the identified fault set. If the power grid system is unstable, reduce the overall phase advance depth of the power plant and proceed to step d. If the power grid system is stable, proceed to step b. b. Determine whether the steady-state voltage exceeds the voltage limit after a DC fault. If it does not exceed the limit, proceed to step c; if it does exceed the limit, proceed to step d. c. Increase the overall phase advance depth of the power plant and return to step a; d. Increase the overall plant retention depth and proceed to step e; e. Determine whether the total pre-phase depth of the plant is less than the maximum pre-phase depth of a single unit. If it is less, proceed to step f. f. Determine whether the steady-state voltage exceeds the voltage limit after a DC fault. If the steady-state overvoltage does not exceed the voltage limit, output the overall phase advance depth and the overall retained phase advance depth of the power plant.

2. The generator leading phase capability analysis method according to claim 1, characterized in that, The range of values ​​for the overall plant retention depth is as follows: Q t -min[Q t ,(M-1) Q s ]≤Q l ≤Q s , Among them, Q l To preserve the depth of the phase advance throughout the plant, Q t Q represents the overall phase advance depth of the power plant. s M represents the maximum depth of advance of a single unit, and M represents the total number of units in the plant.

3. The generator phase-leading capability analysis method according to claim 1, characterized in that, The maximum value for the total plant-wide retained phase advance depth is the total plant-wide retained phase advance depth when only one unit is retained after a DC fault lockout and shutdown.

4. The generator phase-leading capability analysis method according to claim 1, characterized in that, The fault set includes the first, second, and third-level DC transmission sections, the outgoing sections of the leading-phase power plants, and the critical sections of the power grid system.

5. A generator phase-leading capability analysis system, characterized in that, The system includes: First acquisition module: used to obtain the maximum phase advance depth of a single unit based on the stability of the power grid system and the voltage control status of the converter station bus; The second acquisition module is used to obtain the total phase advance depth and the total retained phase advance depth of the power plant based on the maximum phase advance depth of a single unit. The process for obtaining the maximum advance depth of a single machine is as follows: Set the initial value of the maximum advance depth of a single unit to zero; a. Determine whether the power grid system is stable based on the identified fault set; b. If the power grid system is stable, determine whether the converter station bus voltage is within the control range; otherwise, increase the converter station bus voltage and return to step a. c. If the converter station bus voltage is within the control range, increase the maximum phase advance depth of a single unit and return to step a; otherwise, output the maximum phase advance depth of a single unit. The process for obtaining the overall advanced phase depth and the overall retained advanced phase depth of the power plant is as follows: Let the initial value of the total phase advance depth of the power plant be the maximum phase advance depth of a single unit; a. Determine whether the power grid system is stable based on the identified fault set. If the power grid system is unstable, reduce the overall phase advance depth of the power plant and proceed to step d. If the power grid system is stable, proceed to step b. b. Determine whether the steady-state voltage exceeds the voltage limit after a DC fault. If it does not exceed the limit, proceed to step c; if it does exceed the limit, proceed to step d. c. Increase the overall phase advance depth of the power plant and return to step a; d. Increase the overall plant retention depth and proceed to step e; e. Determine whether the total pre-phase depth of the plant is less than the maximum pre-phase depth of a single unit. If it is less, proceed to step f. f. Determine whether the steady-state voltage exceeds the voltage limit after a DC fault. If the steady-state overvoltage does not exceed the voltage limit, output the overall phase advance depth and the overall retained phase advance depth of the power plant.

6. A generator phase-leading capability analysis system, characterized in that, The system includes a processor and a storage medium; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 1-4.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 1-4.

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