Power plant level hyper-synchronous multi-level early warning and shaft system torsional vibration coordination control method and system

Abstract

According to the power plant level super-synchronous multi-level early warning and shaft system torsional vibration coordinated control method and system, when the oscillation time of each piece of monitoring data of an oscillation frequency point is not smaller than a time fixed value of oscillation warning, an early warning instruction is generated according to an early warning rule, and when a first-level early warning instruction is sent, a second-level early warning instruction is sent; when the deviation between the machine head and / or machine tail rotating speed oscillation frequency and the inherent frequency of the thermal power generating unit is not larger than a threshold value, it is judged that machine head and / or machine tail torsional vibration exists in the thermal power generating unit; when the torsional vibration trip-out time of the machine head and / or the machine tail in the oscillation mode is larger than a trip-out time fixed value, a first-level early warning instruction is sent, and a thermal power generating unit trip-out instruction is generated; if the machine head and / or machine tail torsional vibration coordination control time of the oscillation mode is larger than a coordination control time fixed value, or if the first-level early warning instruction is sent, but the machine head and / or machine tail torsional vibration coordination control time of the oscillation mode is smaller than the coordination control time fixed value, a request coordination control instruction is sent to an upper level. And performing graded early warning on safe and stable operation of the thermal power generating unit, and taking measures to prevent the torsional vibration risk.

Description

Technical Field

[0001] The present invention belongs to the field of dynamic monitoring and control of electric power systems, and in particular relates to a method and system for coordinated control of sub-level super-synchronous multi-level early warning and shaft torsional vibration of a power plant. Background Art

[0002] In recent years, due to the increasing penetration rate of new energy sources, mainly wind power and photovoltaic power, in the power system, the power electronics characteristics of the power system have become increasingly prominent. Once these new energy sources are connected to the power grid, due to their power generation characteristics, under specific control modes or operating modes, they are prone to form continuous subsynchronous or supersynchronous harmonics. When these harmonics are injected into the system, they may stimulate shaft torsional vibration of nearby thermal power units, causing chain reactions such as thermal power unit tripping and DC locking, endangering the safe and stable operation of the power grid and affecting the power supply quality.

[0003] In the prior art, the coordinated control of thermal power plant units is to coordinate the rapid start and stop and rapid load increase and decrease of thermal power units, and it is impossible to achieve real-time sub-supersynchronous monitoring and coordinated control of thermal power units in thermal power plants; the coordinated action method of the shaft torsional vibration protection of steam turbine generator units describes the basic principle of the coordinated control master station, but the machine cutting priority ranking is generated in real time by the unit output, and it is impossible to judge the warning level according to the components to be monitored, and it is impossible to combine the inherent frequency information of the thermal power unit and the speed constant and warning level of each modal shaft system to generate two types of protection instructions; the broadband access of new energy with comprehensive multi-source information The multi-level stability warning method is a multi-level warning for regional power grids connected to new energy sources. It is not possible to provide multi-level warnings at the thermal power plant station level, and coordinated control is performed in combination with the warning levels; the engine shaft torsional vibration monitoring issues a shaft torsional vibration risk warning by judging whether the engine is in a transient operating condition, and is not able to give multi-level warnings; the turbine unit shaft torsional vibration risk warning method determines whether to issue a shaft torsional vibration risk warning through the first locking signal, the second locking signal and the transient torque. Such a graded warning cannot meet the needs of real-time sub-supersynchronous monitoring and coordinated control of thermal power units in thermal power plants.

[0004] With the increasing penetration rate of renewable energy in the power grid, the sub-supersynchronous oscillation problem it brings has become increasingly prominent. In order to avoid the thermal power units from exciting shaft torsional vibration and causing the thermal power units to trip, it is very necessary to conduct real-time sub-supersynchronous monitoring and coordinated control of the thermal power units in the thermal power plant. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a power plant-level sub-supersynchronous multi-level early warning and shaft system torsional vibration coordinated control method and system, which integrates the inherent characteristics of torsional vibration and alarm information of the thermal power units in the power plant while performing online monitoring of oscillations within the sub-supersynchronous range, and comprehensively judges and gives graded early warning signals that characterize the impact on the safe and stable operation of the thermal power units, so that operators can promptly discover the sub-supersynchronous oscillation of the power plant, and can take corresponding measures according to the early warning level to effectively prevent the risk of torsional vibration and reduce the loss of machine cutting to a minimum.

[0006] The present invention adopts the following technical solution.

[0007] The present invention proposes a power plant level super-synchronous multi-level early warning and shaft torsional vibration coordinated control method, comprising:

[0008] Acquire monitoring data at each monitoring point of each thermal power unit; perform time-frequency domain transformation on the monitoring data of each thermal power unit to obtain a spectrum data set, use the spectrum data set of each thermal power unit to determine the oscillation frequency of each thermal power unit, and extract the oscillation amplitude of each monitoring data corresponding to the oscillation frequency within a set range;

[0009] Set the amplitude constant and time constant of the oscillation alarm of each monitoring data; when the oscillation amplitude of each monitoring data corresponding to the oscillation frequency is not less than the amplitude constant of the oscillation alarm, it is determined that there is oscillation at the oscillation frequency at each monitoring point, and the ratio of the oscillation amplitude of each monitoring data corresponding to the oscillation frequency to the amplitude constant of the oscillation alarm is used as the oscillation coefficient at the oscillation frequency at each monitoring point; when the oscillation amplitude of each monitoring data corresponding to the oscillation frequency is not less than the amplitude constant of the oscillation alarm and the duration is not less than the set time, the start time is accumulated to obtain the oscillation time of each monitoring data corresponding to the oscillation frequency; when the oscillation amplitude of each monitoring data corresponding to the oscillation frequency is not less than the amplitude constant of the oscillation alarm and the duration is not less than the set time, the start time is accumulated to obtain the oscillation time of each monitoring data corresponding to the oscillation frequency; When the oscillation time is not less than the time setting value of the oscillation alarm, an alarm is issued for the monitoring data at each monitoring point; according to the natural frequency of each thermal power unit, the alarm signal of the monitoring data at each monitoring point, and the oscillation coefficient at the frequency corresponding to the oscillation frequency point at each monitoring point, five levels of early warning instructions are generated according to the early warning rules. When the first level early warning instruction is sent, the deviations of the head speed oscillation frequency and the tail speed oscillation frequency of each thermal power unit from the natural frequency are calculated; when the deviation of the head and / or tail speed oscillation frequency of the thermal power unit from the natural frequency is not greater than the threshold value, it is determined that the thermal power unit has head and / or tail torsional vibration;

[0010] Set the trip amplitude constant, trip time constant, coordinated control amplitude constant and coordinated control time constant of each thermal power unit under different oscillation modes; when the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency of the thermal power unit is not less than the trip amplitude constant under the oscillation mode and the duration is not less than the set time, start the time accumulation to calculate the head and / or tail torsional vibration trip time under the oscillation mode; when the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency of the thermal power unit is not less than the duration of the coordinated control amplitude constant under the oscillation mode, the start time accumulation is started to calculate the head and / or tail torsional vibration trip time under the oscillation mode. When the start time is not less than the set time, the startup time is accumulated to calculate the coordinated control time of the nose or tail torsional vibration in the oscillation mode; when the nose and / or tail torsional vibration tripping time of the oscillation mode is greater than the tripping time setting and the first-level early warning instruction is sent, a tripping instruction of the thermal power unit is generated; when the coordinated control time of the nose and / or tail torsional vibration in the oscillation mode is greater than the coordinated control time setting, or the first-level early warning instruction is sent but the coordinated control time of the nose and / or tail torsional vibration in the oscillation mode is less than the coordinated control time setting, a request for coordinated control instruction is sent to the superior.

[0011] Preferably, the monitoring data at each monitoring point of each thermal power unit includes: three-phase voltage, three-phase current, instantaneous power, excitation voltage, excitation current, head speed and tail speed; the monitoring data of each thermal power unit is transformed in time-frequency domain to obtain a spectrum data set, including:

[0012] Every 100ms, a data window with a length of 1s is used to perform time-frequency domain transformation on the monitoring data of each thermal power unit through the windowed butterfly fast Fourier transform algorithm to obtain a spectrum data set of each thermal power unit, including the frequency value corresponding to each frequency point, the three-phase voltage oscillation amplitude, the three-phase current oscillation amplitude, the instantaneous power oscillation amplitude, the excitation voltage oscillation amplitude, the excitation current oscillation amplitude, the head speed oscillation amplitude and the tail speed oscillation amplitude.

[0013] Preferably, all extreme value points in the spectrum data set of each thermal power unit are obtained; based on all extreme value points, the oscillation frequency points are determined by the double peak spectrum line interpolation method with the frequency error being less than 0.1 Hz and the amplitude error being less than 0.5% as the constraint conditions; and the oscillation amplitudes of each monitoring data corresponding to the oscillation frequency points not less than 5 Hz and not more than 95 Hz are extracted from the spectrum data set of each thermal power unit, including:

[0014] The oscillation frequency f of the mth oscillation frequency point of the jth thermal power unit j_ssom , the voltage oscillation amplitude U of phase A, phase B, and phase C at the mth oscillation frequency point of the jth thermal power unit aj_ssom , U bj_ssom , U cj_ssom , the oscillation amplitude of the current of phase A, phase B, and phase C at the mth oscillation frequency point of the jth thermal power unit I aj_ssom ,I bj_ssom ,Icj_ssom , the instantaneous power oscillation amplitude P of the mth oscillation frequency point of the jth thermal power unit j_ssom , the excitation voltage oscillation amplitude U of the mth oscillation frequency point of the jth thermal power unit Ej_ssom , the excitation current oscillation amplitude I of the mth oscillation frequency point of the jth thermal power unit Ej_ssom , the oscillation amplitude R of the head speed at the mth oscillation frequency point of the jth thermal power unit Hj_ssom , the tail speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Tj_ssom ;

[0015] j=1,2,…,N G , N G is the total number of thermal power units; m=1,2,…,M sso , M sso is the total number of oscillation frequencies.

[0016] Preferably, the amplitude constant U of the three-phase voltage alarm is set abcj_threshold and time setting Amplitude setting value I of three-phase current alarm abcj_threshold and time setting The amplitude setting value P of the instantaneous power alarm j_threshold and time setting Amplitude setting value U of excitation voltage alarm Ej_threshold and time setting Amplitude setting value of excitation current alarm I Ej_threshold and time setting The amplitude constant value R of the head torsional vibration speed alarm Hj_threshold and time setting The amplitude constant value R of the tail torsional vibration speed alarm Tj_threshold and time setting

[0017] Among them, the amplitude value of each monitoring data oscillation alarm is set to 0.02pu, and the time value is set to 20s.

[0018] Preferably, when the oscillation amplitude of each monitoring data corresponding to the oscillation frequency point is not less than the set amplitude fixed value of the oscillation alarm, it is determined that there is an oscillation at the frequency corresponding to the oscillation frequency point at each monitoring point, including:

[0019] When U a(b / c)j_ssom ≥U abcj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom Voltage oscillation under a(b / c)j_ssom is the voltage oscillation amplitude of any phase at the mth oscillation frequency point of the jth thermal power unit;

[0020] When I a(b / c)j_ssom ≥I abcj_thresholdWhen the oscillation frequency f is determined at the monitoring point j_ssom Current oscillation under a(b / c)j_ssom is the oscillation amplitude of any phase current at the mth oscillation frequency point of the jth thermal power unit;

[0021] When P j_ssom ≥P j_threshold When the oscillation frequency f is determined at the monitoring point j_ssom Instantaneous power oscillation under

[0022] When U Ej_ssom ≥U Ej_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The excitation voltage oscillates under

[0023] When I Ej_ssom ≥I Ej_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The excitation current oscillation under

[0024] When R Hj_ssom ≥R Hj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The head speed oscillates under the

[0025] When R Tj_ssom ≥R Tj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The tail speed oscillates under the

[0026] Preferably, when determining that oscillation occurs, the ratio of the oscillation amplitude of each monitoring data corresponding to the extracted oscillation frequency point to the set amplitude constant of the oscillation alarm is used as the oscillation coefficient at the frequency corresponding to the oscillation frequency point at each monitoring point; including:

[0027]

[0028] In the formula, is the three-phase voltage oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit;

[0029]

[0030] In the formula, is the three-phase current oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit;

[0031]

[0032] In the formula, is the oscillation coefficient of the instantaneous power at the mth oscillation frequency point of the jth thermal power unit;

[0033]

[0034] In the formula, is the excitation voltage oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit;

[0035]

[0036] In the formula, is the excitation current oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit;

[0037]

[0038] In the formula, is the oscillation coefficient of the engine speed at the mth oscillation frequency point of the jth thermal power unit;

[0039]

[0040] In the formula, is the tail speed oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit.

[0041] Preferably, when it is determined that oscillation occurs and the duration of the oscillation amplitude of each monitoring data corresponding to the oscillation frequency point is not less than the set amplitude constant value of the oscillation alarm is not less than 1s, the startup time is accumulated, and the oscillation time of each monitoring data corresponding to the oscillation frequency point is calculated according to the following relationship:

[0042] τ k =τ k-1 +Δ×α

[0043] In the formula, τ k is the cumulative time value of each monitoring data corresponding to the oscillation frequency point under the current cumulative number k, τ k-1 is the cumulative time value of each monitoring data corresponding to the oscillation frequency point at the previous cumulative number k-1, α is the oscillation coefficient of each monitoring data corresponding to the oscillation frequency point at the current cumulative number k, Δ is the time difference between the current cumulative number k and the previous cumulative number k-1 for the fast Fourier transform algorithm, and the value of Δ is 100ms.

[0044] Preferably, when the oscillation coefficient of any monitoring data corresponding to the oscillation frequency point is less than 0.5 and the duration is not less than 2s, the oscillation time of any monitoring data corresponding to the oscillation frequency point is cleared;

[0045] When the oscillation coefficient of any monitoring data corresponding to the oscillation frequency point is not less than 0.5 and the duration is not more than 1s, the time accumulation will not be started.

[0046] Preferably, when the oscillation time of each monitoring data corresponding to the oscillation frequency point is not less than the set oscillation alarm time value, an alarm is issued for the monitoring data at each monitoring point, including:

[0047] when When the monitoring point is at the oscillation frequency f j_ssom The voltage under the alarm is alarmed, the alarm mark position is 3, where: is the voltage oscillation time of any phase at the mth oscillation frequency point of the jth thermal power unit;

[0048] when When the monitoring point is at the oscillation frequency f j_ssom The current under the alarm is alarmed, the alarm mark position 2, where, is the oscillation time of any phase current at the mth oscillation frequency point of the jth thermal power unit;

[0049] when When the monitoring point is at the oscillation frequency f j_ssom The instantaneous power under the alarm is alarmed, and the alarm flag position is 1, where: is the instantaneous power oscillation time of the mth oscillation frequency point of the jth thermal power unit;

[0050] when When the monitoring point is at the oscillation frequency f j_ssom The excitation voltage under the alarm is alarmed, the alarm mark position is 4, where, is the excitation voltage oscillation time of the mth oscillation frequency point of the jth thermal power unit;

[0051] when When the monitoring point is at the oscillation frequency f j_ssom The excitation current under the alarm is alarmed, the alarm mark position is 5, where, is the excitation current oscillation time of the mth oscillation frequency point of the jth thermal power unit;

[0052] when When the monitoring point is at the oscillation frequency f j_ssom The nose speed alarm is given at the alarm position 6, where: is the oscillation time of the engine speed at the mth oscillation frequency point of the jth thermal power unit;

[0053] when When the monitoring point is at the oscillation frequency f j_ssom The tail speed alarm is given at the alarm position 7, where: is the tail speed oscillation time of the mth oscillation frequency point of the jth thermal power unit.

[0054] Preferably, the warning rules include:

[0055] 1) Warning sign position 1 at the same time Then send a Level 5 warning instruction;

[0056] 2) Warning sign position 2 at the same time If the alarm flag is set to a value other than 3, 4, 5, 6, or 7, a Level 4 warning command is sent. Then send a Level 4 warning instruction;

[0057] 3) Warning sign position 3 at the same time If the alarm flag is a value other than 4, 5, 6, or 7, a Level 3 warning command is sent; if the alarm flag is in position 2, If the alarm flag is a value other than 3, 4, 5, 6, or 7, a Level 3 warning instruction is sent;

[0058] 4) Warning sign position 4 at the same time If the alarm flag is a value other than 5, 6, or 7, a Level 2 warning command is sent; if the alarm flag is 5, If the alarm flag is a value other than 4, 6, or 7, a Level 2 warning command is sent; if the alarm flag is 4, Warning sign position 5 at the same time If the alarm flag is set to a value other than 6 or 7, a Level 2 warning command is sent; if the alarm flag is set to 3, If the alarm flag is a value other than 4, 5, 6, or 7, a Level 2 warning instruction is sent;

[0059] 5) If the alarm mark is in position 7, a level 1 warning instruction is sent; if the alarm mark is in position 6, a level 1 warning instruction is sent; if the alarm mark is in position 6 and 7, a level 1 warning instruction is sent; if the alarm mark is in position 4 and 7, a level 1 warning instruction is sent; If the alarm flag is a value other than 5, 6, or 7, a Level 1 warning command is sent; if the alarm flag is 5, If the alarm flag is a value other than 4, 6, or 7, a Level 1 warning command is sent; if the alarm flag is 4, Warning sign position 5 at the same time If the alarm flag is a value other than 6 or 7, a Level 1 warning instruction is sent.

[0060] Preferably, the shaft system natural frequency f of the jth thermal power unit within the subsynchronous frequency range is ij As the natural frequency of the thermal power unit, i = 1, 2, ..., n, n is the number of oscillation modes;

[0061] The deviations of the head speed oscillation frequency and tail speed oscillation frequency of the thermal power unit from the natural frequency are both f j_ssom With f ij The absolute value of the difference, the threshold value is 0.25Hz.

[0062] Preferably, the trip amplitude constant R of each thermal power unit under different oscillation modes is set ij_threshold_cut , trip time setting t ij_threshold_cut , coordinated control amplitude setting R ij_threshold_cc And the coordinated control time constant t ij_threshold_cc ;

[0063] When the oscillation mode i is determined to have head torsional vibration, and the head speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Hj_ssom Not less than the trip amplitude setting R under oscillation mode i ij_threshold_cut , the ratio of the head speed oscillation amplitude to the trip amplitude constant under oscillation mode i is taken as the head torsional vibration trip coefficient under oscillation mode i; when it is determined that oscillation mode i occurs tail torsional vibration, and the tail speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Hj_ssom Not less than the trip amplitude setting R under oscillation mode i ij_threshold_cut , the ratio of the tail speed oscillation amplitude to the trip amplitude constant under oscillation mode i is taken as the tail torsional vibration trip coefficient under oscillation mode i;

[0064] When the oscillation mode i is determined to have head torsional vibration, and the head speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Hj_ssom Not less than the coordinated control amplitude constant R under oscillation mode i ij_threshold_cc When the ratio of the head speed oscillation amplitude to the coordinated control amplitude constant under oscillation mode i is taken as the head torsional vibration coordinated control coefficient under oscillation mode i; when it is determined that the tail torsional vibration occurs in oscillation mode i, the tail speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit is Hj_ssom Not less than the coordinated control amplitude constant R under oscillation mode i ij_threshold_cc When , the ratio of the tail speed oscillation amplitude to the coordinated control amplitude constant under oscillation mode i is taken as the tail torsional vibration coordinated control coefficient under oscillation mode i.

[0065] Preferably, when the head speed oscillation amplitude or the tail speed oscillation amplitude of the mth oscillation frequency point of the jth thermal power unit is not less than the trip amplitude setting value under the oscillation mode i for a duration of not less than 1s, the startup time is accumulated, and the head torsional vibration tripping time or the tail torsional vibration tripping time of the oscillation mode i is calculated according to the following relationship:

[0066] τ ik =τ ik-1 +Δ×α i

[0067] In the formula, τ ik is the cumulative time value of the nose torsional vibration tripping or tail torsional vibration tripping of oscillation mode i under the current cumulative number k, τ ik-1is the cumulative time value of the nose torsional vibration tripping or tail torsional vibration tripping of oscillation mode i under the previous cumulative number k-1, α i is the nose torsional vibration tripping coefficient or tail torsional vibration tripping coefficient of oscillation mode i under the current cumulative number k, Δ is the time difference between the current cumulative number k and the previous cumulative number k-1 for fast Fourier transform algorithm, and Δ is 100ms;

[0068] When the oscillation amplitude of the head speed or the tail speed at the mth oscillation frequency point of the jth thermal power unit is not less than the coordinated control amplitude setting value under the oscillation mode i for a duration of not less than 1s, the start time is accumulated, and the head torsional vibration coordinated control time or the tail torsional vibration coordinated control time of the oscillation mode i is calculated according to the following relationship:

[0069] τ′ ik =τ′ ik-1 +Δ×α′ i

[0070] In the formula, τ′ ik is the cumulative time value of the nose torsional vibration coordinated control or tail torsional vibration coordinated control of oscillation mode i under the current cumulative number k, τ′ ik-1 is the cumulative time value of the nose torsional vibration coordinated control or tail torsional vibration coordinated control of oscillation mode i under the last cumulative number k-1, α′ i is the nose torsional vibration coordination control coefficient or the tail torsional vibration coordination control coefficient of the oscillation mode i under the current cumulative number k, Δ is the time difference between the current cumulative number k and the previous cumulative number k-1 for the fast Fourier transform algorithm, and the value of Δ is 100ms.

[0071] Preferably, when the nose torsional vibration trip coefficient or the tail torsional vibration trip coefficient of the oscillation mode i is less than 0.5 and the duration is not less than 2s, the nose torsional vibration trip time or the tail torsional vibration trip time of the oscillation mode i is reset;

[0072] When the nose torsional vibration coordination control coefficient or the tail torsional vibration coordination control coefficient of oscillation mode i is less than 0.5 and the duration is not less than 2s, the nose torsional vibration coordination control time or the tail torsional vibration coordination control time of oscillation mode i is reset;

[0073] When the nose torsional vibration trip coefficient or tail torsional vibration trip coefficient of oscillation mode i is not less than 0.5 and the duration is not more than 1s, the time accumulation will not be started;

[0074] When the nose torsional vibration coordination control coefficient or the tail torsional vibration coordination control coefficient of oscillation mode i is not less than 0.5 and the duration is not more than 1s, the time accumulation is not started.

[0075] Preferably, when the nose torsional vibration tripping time or the tail torsional vibration tripping time of the oscillation mode i is greater than the tripping time setting value and a level 1 warning instruction is sent, a thermal power unit tripping instruction is generated;

[0076] When the nose torsional vibration coordination control time or the tail torsional vibration coordination control time of oscillation mode i is greater than the coordination control time set value, or when the first-level warning command is sent but the nose torsional vibration coordination control time or the tail torsional vibration coordination control time of oscillation mode i is less than the coordination control time set value, a request for coordination control command is sent to the superior.

[0077] The present invention also proposes a power plant level super-synchronous multi-level early warning and shaft system torsional vibration coordinated control system, comprising:

[0078] The oscillation data processing module is used to obtain the monitoring data at each monitoring point of each thermal power unit; perform time-frequency domain transformation on the monitoring data of each thermal power unit to obtain a spectrum data set, use the spectrum data set of each thermal power unit to determine the oscillation frequency of each thermal power unit, and extract the oscillation amplitude of each monitoring data corresponding to the oscillation frequency within a set range;

[0079] The oscillation warning and torsional vibration judgment module is used to set the amplitude constant and time constant of the oscillation alarm of each monitoring data; when the oscillation amplitude of each monitoring data corresponding to the oscillation frequency is not less than the amplitude constant of the oscillation alarm, it is determined that there is oscillation at the oscillation frequency at each monitoring point, and the ratio of the oscillation amplitude of each monitoring data corresponding to the oscillation frequency to the amplitude constant of the oscillation alarm is used as the oscillation coefficient at the oscillation frequency at each monitoring point; when the oscillation amplitude of each monitoring data corresponding to the oscillation frequency is not less than the amplitude constant of the oscillation alarm and the duration is not less than the set time, the start time is accumulated to obtain the oscillation time of each monitoring data corresponding to the oscillation frequency; when the oscillation frequency corresponds to When the oscillation time of each monitoring data is not less than the time setting value of the oscillation alarm, an alarm is issued for the monitoring data at each monitoring point; according to the natural frequency of each thermal power unit, the alarm signal of the monitoring data at each monitoring point, and the oscillation coefficient at the frequency corresponding to the oscillation frequency point at each monitoring point, five levels of early warning instructions are generated according to the early warning rules. When the first level early warning instruction is sent, the deviations of the head speed oscillation frequency and the tail speed oscillation frequency of each thermal power unit from the natural frequency are calculated; when the deviation of the head and / or tail speed oscillation frequency of the thermal power unit from the natural frequency is not greater than the threshold value, it is determined that the thermal power unit has head and / or tail torsional vibration;

[0080] The torsional vibration control module is used to set the trip amplitude constant, trip time constant, coordinated control amplitude constant and coordinated control time constant of each thermal power unit under different oscillation modes; when the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency of the thermal power unit is not less than the trip amplitude constant under the oscillation mode and the duration is not less than the set time, the start time accumulation is used to calculate the head and / or tail torsional vibration trip time under the oscillation mode; when the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency of the thermal power unit is not less than the coordinated control amplitude constant under the oscillation mode, the start time accumulation is used to calculate the head and / or tail torsional vibration trip time under the oscillation mode. When the duration of the start time is not less than the set time, the startup time is accumulated to calculate the coordinated control time of the nose or tail torsional vibration in the oscillation mode; when the tripping time of the nose and / or tail torsional vibration in the oscillation mode is greater than the tripping time setting and the first-level early warning instruction is sent, a tripping instruction of the thermal power unit is generated; when the coordinated control time of the nose and / or tail torsional vibration in the oscillation mode is greater than the coordinated control time setting, or the first-level early warning instruction is sent but the coordinated control time of the nose and / or tail torsional vibration in the oscillation mode is less than the coordinated control time setting, a request for coordinated control instruction is sent to the superior.

[0081] A terminal comprises a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method.

[0082] A computer-readable storage medium stores a computer program, which implements the steps of the method when executed by a processor.

[0083] The beneficial effect of the present invention is that, compared with the prior art, it at least includes oscillation monitoring and shaft torsional vibration control for regional thermal power plants. The present invention connects the three-phase voltage, three-phase current, instantaneous voltage, excitation voltage, excitation current, head speed and tail speed of the thermal power units in the power plant in the time domain sampling system, and performs spectral line analysis on different components in the frequency domain through the windowed butterfly fast Fourier algorithm and the double-peak spectral line interpolation technology. The sub-supersynchronous oscillation modal frequency of each unit in the entire thermal power plant is identified through the spectral line analysis results. Combined with the proposed time accumulation method based on the component oscillation coefficient, the oscillation amplitude, component oscillation coefficient, oscillation time and thermal power unit are comprehensively analyzed. The natural frequency is used to make an alarm judgment on the component, and a multi-level early warning is carried out in combination with the component oscillation coefficient and the component category; the present invention proposes a comprehensive control method for the torsional vibration protection control of the shaft system of the thermal power unit, including the comprehensive speed torsional vibration amplitude, the accumulated torsional vibration time based on the torsional vibration coefficient, the unit torsional vibration modal stability signal, the stability margin coefficient, the natural frequency information and the early warning level based on the component oscillation coefficient and the component category, which provides a new solution for the torsional vibration protection of the shaft system under the constraint of ensuring the stable output of the regional thermal power plant. Under the constraint of ensuring the stable output of the regional thermal power plant, the coordinated control of the shaft system of the thermal power plant can be reliably realized to ensure the safe and stable operation of the grid-connected system of the regional thermal power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Figure 1 The present invention provides a flow chart of the power plant sub-level super-synchronous multi-level early warning and shaft system torsional vibration coordinated control method. DETAILED DESCRIPTION

[0085] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0086] The present invention proposes a power plant level super-synchronous multi-level early warning and shaft torsional vibration coordinated control method, with all thermal power units in the thermal power plant forming the monitoring range, such as Figure 1 As shown, including:

[0087] Step 1, obtaining the monitoring data at each monitoring point of each thermal power unit within the monitoring range; performing time-frequency domain transformation on the monitoring data of each thermal power unit to obtain a spectrum data set, using the spectrum data set of each thermal power unit to determine the oscillation frequency of each thermal power unit, and extracting the oscillation amplitude of each monitoring data corresponding to the oscillation frequency within the set range.

[0088] Acquire the monitoring data at each monitoring point of each thermal power unit within the monitoring range, including: three-phase voltage, three-phase current, instantaneous power, excitation voltage, excitation current, head speed and tail speed.

[0089] Specifically, the three-phase voltage, three-phase current, excitation voltage, excitation current and head and tail speed signals of each thermal power unit in a thermal power plant within the monitoring range are collected in real time; and the instantaneous power of each thermal power unit is calculated using the three-phase voltage and three-phase current.

[0090] Specifically, by deploying voltage transformers and current transformers on the outgoing lines of each thermal power unit within the monitoring range, the three-phase voltage and three-phase current of each thermal power unit are collected in real time;

[0091] By deploying voltage transformers and current transformers for the excitation voltage and excitation current of each thermal power unit within the monitoring range, the excitation voltage and excitation current of each thermal power unit can be collected in real time;

[0092] By deploying speed sensors on the turbine and rotor sides of the thermal power units, the speed of the head and tail of each thermal power unit can be collected in real time.

[0093] The monitoring data of each thermal power unit is transformed in the time-frequency domain to obtain a spectrum data set, and all extreme points in the spectrum data set of each thermal power unit are obtained; based on all extreme points, the oscillation frequency points are determined by the double-peak spectrum line interpolation method; from the spectrum data set of each thermal power unit, the oscillation amplitude of each monitoring data corresponding to the oscillation frequency points not less than 5 Hz and not more than 95 Hz is extracted.

[0094] Every 100ms, a data window with a length of 1s is used to perform time-frequency domain transformation on the monitoring data of each thermal power unit through a windowed butterfly fast Fourier transform algorithm to realize the spectrum calculation function based on the original sampling signal, thereby obtaining a spectrum data set of each thermal power unit, including the frequency value corresponding to each frequency point, the three-phase voltage oscillation amplitude, the three-phase current oscillation amplitude, the instantaneous power oscillation amplitude, the excitation voltage oscillation amplitude, the excitation current oscillation amplitude, the head speed oscillation amplitude, and the tail speed oscillation amplitude;

[0095] Obtain all extreme points in the spectrum data set of each thermal power unit; based on all extreme points, with the frequency error less than 0.1Hz and the amplitude error less than 0.5% as constraints, use the double-peak spectrum line interpolation method to obtain the accurate oscillation frequency and the amplitude corresponding to the oscillation frequency;

[0096] From the spectrum data set of each thermal power unit, extract the oscillation amplitude of each monitoring data corresponding to the oscillation frequency point not less than 5Hz and not more than 95Hz, including:

[0097] The oscillation frequency f of the mth oscillation frequency point of the jth thermal power unit j_ssom , the voltage oscillation amplitude U of phase A, phase B, and phase C at the mth oscillation frequency point of the jth thermal power unit aj_ssom , U bj_ssom , U cj_ssom , the oscillation amplitude of the current of phase A, phase B, and phase C at the mth oscillation frequency point of the jth thermal power unit I aj_ssom ,I bj_ssom ,I cj_ssom , the instantaneous power oscillation amplitude P of the mth oscillation frequency point of the jth thermal power unit j_ssom , the excitation voltage oscillation amplitude U of the mth oscillation frequency point of the jth thermal power unit Ej_ssom , the excitation current oscillation amplitude I of the mth oscillation frequency point of the jth thermal power unit Ej_ssom , the oscillation amplitude R of the head speed at the mth oscillation frequency point of the jth thermal power unit Hj_ssom , the tail speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Tj_ssom .

[0098] j=1,2,…,N G , N G is the total number of thermal power units; m=1,2,…,Msso , M sso is the total number of oscillation frequencies.

[0099] Step 2, setting the amplitude constant and time constant of the oscillation alarm of each monitoring data; when the oscillation amplitude of each monitoring data corresponding to the oscillation frequency point is not less than the amplitude constant of the oscillation alarm, it is determined that there is oscillation at the oscillation frequency point at each monitoring point, and the ratio of the oscillation amplitude of each monitoring data corresponding to the oscillation frequency point to the amplitude constant of the oscillation alarm is used as the oscillation coefficient at the oscillation frequency point at each monitoring point; when the duration of the oscillation amplitude of each monitoring data corresponding to the oscillation frequency point is not less than the amplitude constant of the oscillation alarm is not less than the set time, the start time is accumulated to obtain the oscillation time of each monitoring data corresponding to the oscillation frequency point; when each monitoring data corresponding to the oscillation frequency point When the oscillation time of the data is not less than the time setting of the oscillation alarm, an alarm is issued for the monitoring data at each monitoring point; according to the natural frequency of each thermal power unit, the alarm signal of the monitoring data at each monitoring point, and the oscillation coefficient at the frequency corresponding to the oscillation frequency point at each monitoring point, five levels of early warning instructions are generated according to the early warning rules. When the first level early warning instruction is sent, the deviations of the head speed oscillation frequency and the tail speed oscillation frequency of each thermal power unit from the natural frequency are calculated; when the deviation of the head and / or tail speed oscillation frequency of the thermal power unit from the natural frequency is not greater than the threshold value, it is determined that the thermal power unit has head and / or tail torsional vibration.

[0100] Specifically, step 2 includes:

[0101] Step 2.1: Set the three-phase voltage alarm amplitude constant U abcj_threshold and time setting Amplitude setting value I of three-phase current alarm abcj_threshold and time setting The amplitude setting value P of the instantaneous power alarm j_threshold and time setting Amplitude setting value U of excitation voltage alarm Ej_threshold and time setting Amplitude setting value of excitation current alarm I Ej_threshold and time setting The amplitude constant value R of the head torsional vibration speed alarm Hj_threshold and time setting The amplitude constant value R of the tail torsional vibration speed alarm Tj_threshold and time setting

[0102] In the embodiment, the amplitude constant is 0.02pu, and the time constant is 20s, which can also be manually set according to the actual operation conditions and standards of the power plant.

[0103] Step 2.2, when the oscillation amplitude of each monitoring data corresponding to the oscillation frequency point is not less than the set amplitude value of the oscillation alarm, it is determined that there is oscillation at the frequency corresponding to the oscillation frequency point at each monitoring point; including:

[0104] When U a(b / c)j_ssom ≥U abcj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom Voltage oscillation under a(b / c)j_ssom is the voltage oscillation amplitude of any phase at the mth oscillation frequency point of the jth thermal power unit;

[0105] When I a(b / c)j_ssom ≥I abcj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom Current oscillation under a(b / c)j_ssom is the oscillation amplitude of any phase current at the mth oscillation frequency point of the jth thermal power unit;

[0106] When P j_ssom ≥P j_threshold When the oscillation frequency f is determined at the monitoring point j_ssom Instantaneous power oscillation under

[0107] When U Ej_ssom ≥U Ej_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The excitation voltage oscillates under

[0108] When I Ej_ssom ≥I Ej_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The excitation current oscillation under

[0109] When R Hj_ssom ≥R Hj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The head speed oscillates under the

[0110] When R Tj_ssom ≥R Tj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The tail speed oscillates under the

[0111] Step 2.3, when it is determined that oscillation occurs, the ratio of the oscillation amplitude of each monitoring data corresponding to the extracted oscillation frequency point to the set amplitude value of the oscillation alarm is used as the oscillation coefficient at the frequency corresponding to the oscillation frequency point at each monitoring point; including:

[0112]

[0113] In the formula, is the three-phase voltage oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit;

[0114]

[0115] In the formula, is the three-phase current oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit;

[0116]

[0117] In the formula, is the oscillation coefficient of the instantaneous power at the mth oscillation frequency point of the jth thermal power unit;

[0118]

[0119] In the formula, is the excitation voltage oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit;

[0120]

[0121] In the formula, is the excitation current oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit;

[0122]

[0123] In the formula, is the oscillation coefficient of the engine speed at the mth oscillation frequency point of the jth thermal power unit;

[0124]

[0125] In the formula, is the tail speed oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit.

[0126] Step 2.4, when it is determined that oscillation occurs and the oscillation amplitude of each monitoring data corresponding to the oscillation frequency point is not less than the set oscillation alarm amplitude constant value and the duration is not less than 1s, the startup time is accumulated and the oscillation time of each monitoring data corresponding to the oscillation frequency point is calculated using the following relationship:

[0127] τ k =τ k-1 +Δ×α

[0128] In the formula, τ k is the cumulative time value of each monitoring data corresponding to the oscillation frequency point under the current cumulative number k, τ k-1is the cumulative time value of each monitoring data corresponding to the oscillation frequency point at the previous cumulative number k-1, α is the oscillation coefficient of each monitoring data corresponding to the oscillation frequency point at the current cumulative number k, Δ is the time difference between the current cumulative number k and the previous cumulative number k-1 for performing the fast Fourier transform algorithm, and in the embodiment, Δ is 100ms.

[0129] In order to avoid a long time interval between two oscillations and the disappearance of the oscillation in the middle, which results in the second oscillation time being accumulated on the basis of the accumulated time of the first oscillation, an oscillation time clearing strategy is set, including: when the oscillation coefficient of any monitoring data corresponding to the oscillation frequency point is less than 0.5 and the duration is not less than 2s, the oscillation time of the monitoring data corresponding to the oscillation frequency point is cleared.

[0130] In order to avoid the problem that the oscillation continues to exist between two oscillations, but the oscillation amplitude is small in the middle, resulting in a long alarm time, a constant oscillation time strategy is set, including: when the oscillation coefficient of any monitoring data corresponding to the oscillation frequency point is not less than 0.5 and the duration is not more than 1s, the time accumulation will not be started.

[0131] Step 2.5, when the oscillation time of each monitoring data corresponding to the oscillation frequency point is not less than the set oscillation alarm time value, an alarm is issued for the monitoring data at each monitoring point;

[0132] when When the monitoring point is at the oscillation frequency f j_ssom The voltage under the alarm is alarmed, the alarm mark position is 3, where: is the voltage oscillation time of any phase at the mth oscillation frequency point of the jth thermal power unit;

[0133] when When the monitoring point is at the oscillation frequency f j_ssom The current under the alarm is alarmed, the alarm mark position 2, where, is the oscillation time of any phase current at the mth oscillation frequency point of the jth thermal power unit;

[0134] when When the monitoring point is at the oscillation frequency f j_ssom The instantaneous power under the alarm is alarmed, and the alarm flag position is 1, where: is the instantaneous power oscillation time of the mth oscillation frequency point of the jth thermal power unit;

[0135] when When the monitoring point is at the oscillation frequency f j_ssom The excitation voltage under the alarm is alarmed, the alarm mark position is 4, where, is the excitation voltage oscillation time of the mth oscillation frequency point of the jth thermal power unit;

[0136] when When the monitoring point is at the oscillation frequency f j_ssom The excitation current under the alarm is alarmed, the alarm mark position is 5, where, is the excitation current oscillation time of the mth oscillation frequency point of the jth thermal power unit;

[0137] when When the monitoring point is at the oscillation frequency f j_ssom The nose speed alarm is given at the alarm position 6, where: is the oscillation time of the engine speed at the mth oscillation frequency point of the jth thermal power unit;

[0138] when When the monitoring point is at the oscillation frequency f j_ssom The tail speed alarm is given at the alarm position 7, where: is the tail speed oscillation time of the mth oscillation frequency point of the jth thermal power unit.

[0139] Step 2.6, taking the shaft system natural frequency of each thermal power unit within the subsynchronous frequency range as the natural frequency of each thermal power unit;

[0140] The natural frequency of a thermal power unit refers to the natural frequency of the shaft system of the unit within the subsynchronous frequency range. ij , i = 1, 2, ..., n, n is the number of oscillation modes; generally, there are 2 to 3 natural frequencies in a thermal power unit. The specific parameters are provided by the thermal power plant or can be obtained through wave analysis at the start-up time of the thermal power unit;

[0141] Step 2.7, based on the natural frequency information of each thermal power unit, the alarm signal of the monitoring data at each monitoring point, and the oscillation coefficient at the frequency corresponding to the oscillation frequency point at each monitoring point, in the embodiment, a multi-level warning instruction is generated according to the warning rules shown in Table 1. In Table 1, the first level warning level is the highest, indicating that the danger is the most serious, the second level is second, the third level is third, the fourth level is third, and the fifth level warning level is the lowest, which only requires attention.

[0142] Table 1 Warning rules

[0143]

[0144]

[0145] The design of early warning levels follows the following principles:

[0146] 1) The risk severity levels are as follows: shaft side oscillation risk > excitation side electrical oscillation risk > machine side electrical oscillation risk;

[0147] 2) Among the electrical quantities on the machine side, according to the sensitivity of oscillation detection during oscillation (in the power system, the current oscillation has a larger amplitude than the voltage oscillation, which is easier to detect, and both current oscillation and voltage oscillation will cause power oscillation. When the current oscillation is relatively small and difficult to detect, the oscillation power is the coupling result of the oscillating current and the power frequency voltage, and the amplitude is relatively large, which can be better detected; similarly, when the voltage oscillation is relatively small and difficult to detect, the oscillation power is the coupling result of the oscillating voltage and the power frequency current, and the amplitude is relatively large, which can be better detected), the best oscillation component to detect is power, followed by current, and finally voltage. In the power system, current oscillation and voltage oscillation will be reflected in power oscillation. When the current and voltage oscillations are small and difficult to detect, the power oscillation will generally be relatively obvious. Therefore, when only the instantaneous power oscillates, it is considered that the warning level is the lowest, which is the 5th level warning instruction, and only attention is needed. However, when the instantaneous power oscillation coefficient is too high (generally, an oscillation coefficient greater than 3 is considered too high), it is considered that the oscillation is too large and the warning level is increased by one level. When the current oscillates, the warning level is level 4. When the current element oscillation coefficient is too high (generally, an oscillation coefficient greater than 3 is considered too high), the warning level is increased by one level. When the voltage oscillates, the warning level is level 3. When the voltage element oscillation coefficient is too high (generally, an oscillation coefficient greater than 3 is considered too high), the warning level is increased by one level.

[0148] 3) When the electrical quantity on the excitation side oscillates, whether it is the excitation voltage or the excitation current, it can be considered that the current oscillation impact is relatively severe and needs to be paid attention to. The warning level is level 2. When the oscillation coefficient of the excitation voltage or the excitation current is too high (generally, the oscillation coefficient is greater than 3, which is considered too high), the warning level is increased by one level;

[0149] 4) Whenever oscillation occurs at the nose or tail of the aircraft, it is considered that the current oscillation impact is extremely severe and preparations should be made according to Level 1.

[0150] If the alarm mark is in position 7, the first-level alarm command is sent and the deviation between the tail speed oscillation frequency and the natural frequency of each thermal power unit is calculated; if the alarm mark is in position 6, the first-level alarm command is sent and the deviation between the head speed oscillation frequency and the natural frequency of each thermal power unit is calculated; if the alarm mark is in position 6 and 7, the first-level alarm command is sent and the deviation between the head and tail speed oscillation frequencies and the natural frequency of each thermal power unit is calculated; when the deviation between the head speed oscillation frequency and the natural frequency of the thermal power unit is not greater than 0.25 Hz, it is determined that the thermal power unit has a head torsional vibration; when the deviation between the tail speed oscillation frequency and the natural frequency of the thermal power unit is not greater than 0.25 Hz, it is determined that the thermal power unit has a tail torsional vibration.

[0151] Warning rules, including:

[0152] 1) Warning sign position 1 at the same time Then send a Level 5 warning instruction;

[0153] 2) Warning sign position 2 at the same time If the alarm flag is set to a value other than 3, 4, 5, 6, or 7, a Level 4 warning command is sent. Then send a Level 4 warning instruction;

[0154] 3) Warning sign position 3 at the same time If the alarm flag is a value other than 4, 5, 6, or 7, a Level 3 warning command is sent; if the alarm flag is in position 2, If the alarm flag is a value other than 3, 4, 5, 6, or 7, a Level 3 warning instruction is sent;

[0155] 4) Warning sign position 4 at the same time If the alarm flag is a value other than 5, 6, or 7, a Level 2 warning command is sent; if the alarm flag is 5, If the alarm flag is a value other than 4, 6, or 7, a Level 2 warning command is sent; if the alarm flag is 4, Warning sign position 5 at the same time If the alarm flag is set to a value other than 6 or 7, a Level 2 warning command is sent; if the alarm flag is set to 3, If the alarm flag is a value other than 4, 5, 6, or 7, a Level 2 warning instruction is sent;

[0156] 5) If the alarm mark is in position 7, a level 1 warning instruction is sent; if the alarm mark is in position 6, a level 1 warning instruction is sent; if the alarm mark is in position 6 and 7, a level 1 warning instruction is sent; if the alarm mark is in position 4 and 7, a level 1 warning instruction is sent; If the alarm flag is a value other than 5, 6, or 7, a Level 1 warning command is sent; if the alarm flag is 5, If the alarm flag is a value other than 4, 6, or 7, a Level 1 warning command is sent; if the alarm flag is 4, Warning sign position 5 at the same time If the alarm flag is a value other than 6 or 7, a Level 1 warning instruction is sent.

[0157] In the embodiment, when the head torsional vibration of the thermal power unit is more sensitive than the tail torsional vibration, if the deviation between the head torsional vibration frequency and the natural frequency of the thermal power unit is within 0.25 Hz, that is: |f j_ssom -f 1j |≤0.25Hz or |f j_ssom -f 2j |≤0.25Hz…or|f j_ssom -f nj|≤0.25Hz and the nose torsional vibration element alarms, it is considered that the oscillation is extremely serious and will cause serious torsional vibration fatigue damage to the thermal power unit, and the warning level is level 1; conversely, when the tail torsional vibration of the thermal power unit is more sensitive than the nose torsional vibration, if the deviation between the tail torsional vibration frequency and the natural frequency of the thermal power unit is within 0.25Hz, that is: |f j_ssom -f 1j |≤0.25Hz or |f j_ssom -f 2j |≤0.25Hz…or|f j_ssom -f nj |≤0.25Hz and the tail torsional vibration element alarms, the oscillation is considered to be extremely serious and will cause serious torsional vibration fatigue damage to the thermal power unit. The warning level is Level 1.

[0158] Step 3, set the trip amplitude constant, trip time constant, coordinated control amplitude constant and coordinated control time constant of each thermal power unit under different oscillation modes; when the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency of the thermal power unit is not less than the duration of the trip amplitude constant under the oscillation mode is not less than the set time, start the time accumulation to calculate the head and / or tail torsional vibration trip time under the oscillation mode; when the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency of the thermal power unit is not less than the duration of the coordinated control amplitude constant under the oscillation mode .... When the duration is not less than the set time, the start time is accumulated to calculate the coordinated control time of the nose or tail torsional vibration in the oscillation mode; when the tripping time of the nose and / or tail torsional vibration in the oscillation mode is greater than the tripping time setting and the first-level early warning instruction is sent, a tripping instruction for the thermal power unit is generated; when the coordinated control time of the nose and / or tail torsional vibration in the oscillation mode is greater than the coordinated control time setting, or the first-level early warning instruction is sent but the coordinated control time of the nose and / or tail torsional vibration in the oscillation mode is less than the coordinated control time setting, a request for coordinated control instruction is sent to the superior.

[0159] Set the trip amplitude constant R of each thermal power unit under different oscillation modes ij_threshold_cut , trip time setting t ij_threshold_cut , coordinated control amplitude setting R ij_threshold_cc And the coordinated control time constant t ij_threshold_cc ;

[0160] When the oscillation mode i is determined to have head torsional vibration, and the head speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Hj_ssom Not less than the trip amplitude setting R under oscillation mode i ij_threshold_cut , the ratio of the head speed oscillation amplitude to the trip amplitude constant under oscillation mode i is taken as the head torsional vibration trip coefficient under oscillation mode i; when it is determined that oscillation mode i occurs tail torsional vibration, and the tail speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Hj_ssomNot less than the trip amplitude setting R under oscillation mode i ij_threshold_cut , the ratio of the tail speed oscillation amplitude to the trip amplitude constant under oscillation mode i is taken as the tail torsional vibration trip coefficient under oscillation mode i;

[0161] When the oscillation mode i is determined to have head torsional vibration, and the head speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Hj_ssom Not less than the coordinated control amplitude constant R under oscillation mode i ij_threshold_cc When the ratio of the head speed oscillation amplitude to the coordinated control amplitude constant under oscillation mode i is taken as the head torsional vibration coordinated control coefficient under oscillation mode i; when it is determined that the tail torsional vibration occurs in oscillation mode i, the tail speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit is Hj_ssom Not less than the coordinated control amplitude constant R under oscillation mode i ij_threshold_cc When , the ratio of the tail speed oscillation amplitude to the coordinated control amplitude constant under oscillation mode i is taken as the tail torsional vibration coordinated control coefficient under oscillation mode i.

[0162] When the head speed oscillation amplitude or tail speed oscillation amplitude of the mth oscillation frequency point of the jth thermal power unit is not less than the trip amplitude setting value under the oscillation mode i for a duration of not less than 1s, the start time is accumulated, and the head torsional vibration trip time or tail torsional vibration trip time of the oscillation mode i is calculated according to the following relationship:

[0163] τ ik =τ ik-1 +Δ×α i

[0164] In the formula, τ ik is the cumulative time value of the nose torsional vibration tripping or tail torsional vibration tripping of oscillation mode i under the current cumulative number k, τ ik-1 is the cumulative time value of the nose torsional vibration tripping or tail torsional vibration tripping of oscillation mode i under the previous cumulative number k-1, α i is the nose torsional vibration tripping coefficient or tail torsional vibration tripping coefficient of oscillation mode i under the current cumulative number k, Δ is the time difference between the current cumulative number k and the previous cumulative number k-1 for fast Fourier transform algorithm, and Δ is 100ms;

[0165] When the oscillation amplitude of the head speed or the tail speed at the mth oscillation frequency point of the jth thermal power unit is not less than the coordinated control amplitude setting value under the oscillation mode i for a duration of not less than 1s, the start time is accumulated, and the head torsional vibration coordinated control time or the tail torsional vibration coordinated control time of the oscillation mode i is calculated according to the following relationship:

[0166] τ′ ik =τ′ ik-1 +Δ×α′ i

[0167] In the formula, τ′ ik is the cumulative time value of the nose torsional vibration coordinated control or tail torsional vibration coordinated control of oscillation mode i under the current cumulative number k, τ′ ik-1 is the cumulative time value of the nose torsional vibration coordinated control or tail torsional vibration coordinated control of oscillation mode i under the last cumulative number k-1, α′ i is the nose torsional vibration coordination control coefficient or the tail torsional vibration coordination control coefficient of the oscillation mode i under the current cumulative number k, Δ is the time difference between the current cumulative number k and the previous cumulative number k-1 for the fast Fourier transform algorithm, and the value of Δ is 100ms.

[0168] When the nose torsional vibration trip coefficient or the tail torsional vibration trip coefficient of oscillation mode i is less than 0.5 and the duration is not less than 2s, the nose torsional vibration trip time or the tail torsional vibration trip time of oscillation mode i is reset;

[0169] When the nose torsional vibration coordination control coefficient or the tail torsional vibration coordination control coefficient of oscillation mode i is less than 0.5 and the duration is not less than 2s, the nose torsional vibration coordination control time or the tail torsional vibration coordination control time of oscillation mode i is reset;

[0170] When the nose torsional vibration trip coefficient or tail torsional vibration trip coefficient of oscillation mode i is not less than 0.5 and the duration is not more than 1s, the time accumulation will not be started;

[0171] When the nose torsional vibration coordination control coefficient or the tail torsional vibration coordination control coefficient of oscillation mode i is not less than 0.5 and the duration is not more than 1s, the time accumulation is not started.

[0172] When the head torsional vibration tripping time or the tail torsional vibration tripping time of oscillation mode i is greater than the tripping time setting value and the first level warning command is sent, a thermal power unit tripping command is generated;

[0173] In the embodiment, when the nose torsional vibration tripping time or the tail torsional vibration tripping time of the oscillation mode i is greater than the tripping time setting value and a first-level warning instruction is sent, it is considered that the torsional vibration of the thermal power unit under the oscillation mode has exceeded the modal torsional vibration tolerance range of the unit, and a first-class protection instruction "direct tripping" instruction is directly generated to drive the "execution" mechanism to immediately disconnect the main switch of the corresponding unit to protect the generator unit; the judgment method of each oscillation mode is the same.

[0174] When the nose torsional vibration coordination control time or the tail torsional vibration coordination control time of oscillation mode i is greater than the coordination control time set value, or when the first-level warning command is sent but the nose torsional vibration coordination control time or the tail torsional vibration coordination control time of oscillation mode i is less than the coordination control time set value, a request for coordination control command is sent to the superior.

[0175] In the embodiment, when the coordinated control time of the nose torsional vibration or the coordinated control time of the tail torsional vibration of the oscillation mode i is greater than the set value of the coordinated control time, or when the first level warning instruction is sent but the coordinated control time of the nose torsional vibration or the coordinated control time of the tail torsional vibration of the oscillation mode i is less than the set value of the coordinated control time, it is considered that the torsional vibration of the thermal power unit under the oscillation mode is still within the torsional vibration tolerance range of the unit, and a second type of protection instruction "coordinated decision" instruction is generated and uploaded to Tmaster. The "coordinated decision" instruction includes the "Stable" signal of the unit torsional vibration mode, the stability margin coefficient, and the warning level; the judgment method of each oscillation mode is the same.

[0176] Among them, Stable=1 means that the torsional vibration mode is stable, and Stable=0 means that the torsional vibration mode is unstable. The stability margin coefficient is negative, and the larger the absolute value, the faster the divergence of the unit torsional vibration mode and the more unstable it is; the stability margin coefficient is 0, indicating that the mode is of equal amplitude oscillation; the stability margin coefficient is positive, and the larger the value, the faster the convergence speed. When the unit stability margin coefficient is less than 0 or the unit stability margin coefficient is equal to 0 and the warning level is higher than level 3, the torsional vibration mode is unstable, Stable=0; otherwise, the torsional vibration mode is stable, Stable=1.

[0177] After integrating the "coordinated decision" instructions of all units, Tmaster issues plant-level protection instructions, indicating which units should be cut off to effectively prevent the risk of torsional vibration and minimize the loss of cutting. Tmaster collects the "coordinated decision" instructions uploaded by each unit and executes the following logical process to decide whether and how to issue a coordinated cutting command, including:

[0178] 1) Information scanning: Tmaster scans the "coordinated decision-making" instructions of each thermal power unit in real time. Once it detects that the "Stable" signal of a unit jumps from 1 to 0, it starts timing and continues scanning for 50ms. When the timing ends, if there is a "Stable=0" situation, execute the next step, otherwise clear the timing and continue scanning.

[0179] 2) Selective cutting: Tmaster selects the unit with the most unstable torsional vibration mode according to the unit stability margin coefficient and warning level, issues a trip command to it, and then detects the switch status of the corresponding unit. If the unit is successfully cut off within 50ms, Tmaster executes the next step. The waiting time of 50ms is set here, which is enough for the actuator to open and close the main switch of the unit. Otherwise, it is considered that the equipment is faulty, Tmaster will issue an alarm message, and send the cutting command to the most unstable unit except the unit with equipment failure.

[0180] 3) Waiting for response: After a predefined time (corresponding to the constant value T wait), Tmaster waits for the system response characteristics after the machine is cut off, while still scanning and recording the unit upload information. wait At the end, if the torsional vibration modes of all online generators are determined to be stable, it means that the aforementioned machine cutting operation has stabilized the system, and Tmaster returns to the normal information scanning state 1); otherwise, it returns to the previous step and continues the selective machine cutting operation.

[0181] Through the shaft speed of the thermal power unit, combined with the inherent torsional vibration characteristics and warning level of the thermal power unit, a comprehensive judgment is given to give a "direct trip" instruction and a "coordinated decision-making" instruction. The "direct trip" instruction is used to drive the "execution" mechanism to immediately disconnect the main switch of the corresponding unit to protect the generator unit. The "coordinated decision-making" instruction is uploaded to the coordinated control master station (Tmaster), and the latter integrates the "coordinated decision-making" instructions of all units, and then makes a power plant-level coordinated protection instruction to indicate which units should be cut off.

[0182] The present invention also proposes a power plant level super-synchronous multi-level early warning and shaft system torsional vibration coordinated control system, comprising:

[0183] The oscillation data processing module is used to obtain the monitoring data at each monitoring point of each thermal power unit; perform time-frequency domain transformation on the monitoring data of each thermal power unit to obtain a spectrum data set, use the spectrum data set of each thermal power unit to determine the oscillation frequency of each thermal power unit, and extract the oscillation amplitude of each monitoring data corresponding to the oscillation frequency within a set range;

[0184] The oscillation warning and torsional vibration judgment module is used to set the amplitude constant and time constant of the oscillation alarm of each monitoring data; when the oscillation amplitude of each monitoring data corresponding to the oscillation frequency is not less than the amplitude constant of the oscillation alarm, it is determined that there is oscillation at the oscillation frequency at each monitoring point, and the ratio of the oscillation amplitude of each monitoring data corresponding to the oscillation frequency to the amplitude constant of the oscillation alarm is used as the oscillation coefficient at the oscillation frequency at each monitoring point; when the oscillation amplitude of each monitoring data corresponding to the oscillation frequency is not less than the amplitude constant of the oscillation alarm and the duration is not less than the set time, the start time is accumulated to obtain the oscillation time of each monitoring data corresponding to the oscillation frequency; when the oscillation frequency corresponds to When the oscillation time of each monitoring data is not less than the time setting value of the oscillation alarm, an alarm is issued for the monitoring data at each monitoring point; according to the natural frequency of each thermal power unit, the alarm signal of the monitoring data at each monitoring point, and the oscillation coefficient at the frequency corresponding to the oscillation frequency point at each monitoring point, five levels of early warning instructions are generated according to the early warning rules. When the first level early warning instruction is sent, the deviations of the head speed oscillation frequency and the tail speed oscillation frequency of each thermal power unit from the natural frequency are calculated; when the deviation of the head and / or tail speed oscillation frequency of the thermal power unit from the natural frequency is not greater than the threshold value, it is determined that the thermal power unit has head and / or tail torsional vibration;

[0185] The torsional vibration control module is used to set the trip amplitude constant, trip time constant, coordinated control amplitude constant and coordinated control time constant of each thermal power unit under different oscillation modes; when the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency of the thermal power unit is not less than the trip amplitude constant under the oscillation mode and the duration is not less than the set time, the start time accumulation is used to calculate the head and / or tail torsional vibration trip time under the oscillation mode; when the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency of the thermal power unit is not less than the coordinated control amplitude constant under the oscillation mode, the start time accumulation is used to calculate the head and / or tail torsional vibration trip time under the oscillation mode. When the duration of the start time is not less than the set time, the startup time is accumulated to calculate the coordinated control time of the nose or tail torsional vibration in the oscillation mode; when the tripping time of the nose and / or tail torsional vibration in the oscillation mode is greater than the tripping time setting and the first-level early warning instruction is sent, a tripping instruction of the thermal power unit is generated; when the coordinated control time of the nose and / or tail torsional vibration in the oscillation mode is greater than the coordinated control time setting, or the first-level early warning instruction is sent but the coordinated control time of the nose and / or tail torsional vibration in the oscillation mode is less than the coordinated control time setting, a request for coordinated control instruction is sent to the superior.

[0186] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0187] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0188] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0189] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages-such as Smalltalk, C++, etc., and conventional procedural programming languages-such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network-including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA) may be personalized by utilizing the state information of a computer-readable program instruction, and the electronic circuit may execute a computer-readable program instruction, thereby realizing various aspects of the present disclosure.

[0190] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for coordinated control of sub-level super-synchronous multi-level early warning and shaft torsional vibration of a power plant, characterized in that: include: Obtain monitoring data at each monitoring point of each thermal power unit; Performing time-frequency domain transformation on the monitoring data of each thermal power unit to obtain a spectrum data set, using the spectrum data set of each thermal power unit to determine the oscillation frequency of each thermal power unit, and extracting the oscillation amplitude of each monitoring data corresponding to the oscillation frequency within a set range; Set the amplitude and time values ​​of the oscillation alarms for each monitoring data; When the oscillation amplitude of each monitoring data corresponding to the oscillation frequency is not less than the amplitude setting value of the oscillation alarm, it is determined that there is oscillation at the oscillation frequency at each monitoring point, and the ratio of the oscillation amplitude of each monitoring data corresponding to the oscillation frequency to the amplitude setting value of the oscillation alarm is used as the oscillation coefficient at the oscillation frequency at each monitoring point; when the duration of the oscillation amplitude of each monitoring data corresponding to the oscillation frequency being not less than the amplitude setting value of the oscillation alarm is not less than the set time, the start time is accumulated to obtain the oscillation time of each monitoring data corresponding to the oscillation frequency; When the oscillation time of each monitoring data corresponding to the oscillation frequency point is not less than the time setting value of the oscillation alarm, an alarm is issued for the monitoring data at each monitoring point; according to the natural frequency of each thermal power unit, the alarm signal of the monitoring data at each monitoring point, and the oscillation coefficient at the frequency corresponding to the oscillation frequency point at each monitoring point, five levels of early warning instructions are generated according to the early warning rules. When the first level early warning instruction is sent, the deviations of the head speed oscillation frequency and the tail speed oscillation frequency of each thermal power unit from the natural frequency are calculated; when the deviation of the head and / or tail speed oscillation frequency of the thermal power unit from the natural frequency is not greater than the threshold value, it is determined that the thermal power unit has head and / or tail torsional vibration; Set the trip amplitude setting value, trip time setting value, coordinated control amplitude setting value and coordinated control time setting value of each thermal power unit under different oscillation modes; when the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency point of the thermal power unit is not less than the trip amplitude setting value under the oscillation mode and the duration is not less than the set time, start the time accumulation to calculate the head and / or tail torsional vibration trip time under the oscillation mode; When the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency of the thermal power unit is not less than the coordinated control amplitude setting value under the oscillation mode and the duration is not less than the set time, the start time is accumulated to calculate the head or tail torsional vibration coordinated control time under the oscillation mode; when the head and / or tail torsional vibration tripping time of the oscillation mode is greater than the tripping time setting value and the first level early warning instruction is sent, a thermal power unit tripping instruction is generated; when the head and / or tail torsional vibration coordinated control time of the oscillation mode is greater than the coordinated control time setting value, or the first level early warning instruction is sent but the head and / or tail torsional vibration coordinated control time of the oscillation mode is less than the coordinated control time setting value, a request for coordinated control instruction is sent to the superior.

2. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 1 is characterized in that: The monitoring data at each monitoring point of each thermal power unit include: three-phase voltage, three-phase current, instantaneous power, excitation voltage, excitation current, head speed and tail speed; The monitoring data of each thermal power unit is transformed into the time-frequency domain to obtain a spectrum data set, including: Every 100ms, a data window with a length of 1s is used to perform time-frequency domain transformation on the monitoring data of each thermal power unit through the windowed butterfly fast Fourier transform algorithm to obtain a spectrum data set of each thermal power unit, including the frequency value corresponding to each frequency point, the three-phase voltage oscillation amplitude, the three-phase current oscillation amplitude, the instantaneous power oscillation amplitude, the excitation voltage oscillation amplitude, the excitation current oscillation amplitude, the head speed oscillation amplitude and the tail speed oscillation amplitude.

3. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 2 is characterized in that: Obtain all extreme points in the spectrum data set of each thermal power unit; according to all extreme points, with the frequency error less than 0.1Hz and the amplitude error less than 0.5% as constraints, use the double peak spectrum line interpolation method to determine the oscillation frequency; from the spectrum data set of each thermal power unit, extract the oscillation amplitude of each monitoring data corresponding to the oscillation frequency not less than 5Hz and not more than 95Hz, including: The oscillation frequency f of the mth oscillation frequency point of the jth thermal power unit j_ssom , the voltage oscillation amplitude U of phase A, phase B, and phase C at the mth oscillation frequency point of the jth thermal power unit aj_ssom , U bj_ssom , U cj_ssom , the oscillation amplitude of the current of phase A, phase B, and phase C at the mth oscillation frequency point of the jth thermal power unit I aj_ssom ,I bj_ssom ,I cj_ssom , the instantaneous power oscillation amplitude P of the mth oscillation frequency point of the jth thermal power unit j_ssom , the excitation voltage oscillation amplitude U of the mth oscillation frequency point of the jth thermal power unit Ej_ssom , the excitation current oscillation amplitude I of the mth oscillation frequency point of the jth thermal power unit Ej_ssom , the oscillation amplitude R of the head speed at the mth oscillation frequency point of the jth thermal power unit Hj_ssom , the tail speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Tj_ssom ; j=1,2,…,N G , N G is the total number of thermal power units; m=1,2,…,M sso , M sso is the total number of oscillation frequencies.

4. The power plant level super-synchronous multi-level early warning and shaft torsional vibration coordinated control method according to claim 3 is characterized in that: Set the amplitude constant U of the three-phase voltage alarm abcj_threshold and time setting Amplitude setting value I of three-phase current alarm abcj_threshold and time setting The amplitude setting value P of the instantaneous power alarm j_threshold and time setting Amplitude setting value U of excitation voltage alarm Ej_threshold and time setting Amplitude setting value of excitation current alarm I Ej_threshold and time setting Amplitude setting value R of the head torsional vibration speed alarm Hj_threshold and time setting The amplitude constant value R of the tail torsional vibration speed alarm Tj_threshold and time setting Among them, the amplitude value of each monitoring data oscillation alarm is set to 0.02pu, and the time value is set to 20s.

5. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 4 is characterized in that: When the oscillation amplitude of each monitoring data corresponding to the oscillation frequency point is not less than the set amplitude value of the oscillation alarm, it is determined that there is oscillation at the frequency corresponding to the oscillation frequency point at each monitoring point, including: When U a(b / c ) j_ssom ≥U abcj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom Voltage oscillation under a(b / c ) j_ssom is the voltage oscillation amplitude of any phase at the mth oscillation frequency point of the jth thermal power unit; When I a(b / c ) j_ssom ≥I abcj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom Current oscillation under a(b / c ) j_ssom is the oscillation amplitude of any phase current at the mth oscillation frequency point of the jth thermal power unit; When P j_ssom ≥P j_threshold When the oscillation frequency f is determined at the monitoring point j_ssom Instantaneous power oscillation under When U Ej_ssom ≥U Ej_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The excitation voltage oscillates under When I Ej_ssom ≥I Ej_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The excitation current oscillation under When R Hj_ssom ≥R Hj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The head speed oscillates under the When R Tj_ssom ≥R Tj_threshold When the oscillation frequency f is determined at the monitoring point j_ssom The tail speed oscillates under the 6. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 5 is characterized in that: When determining that oscillation occurs, the ratio of the oscillation amplitude of each monitoring data corresponding to the extracted oscillation frequency point to the set amplitude value of the oscillation alarm is used as the oscillation coefficient at the frequency corresponding to the oscillation frequency point at each monitoring point; include: In the formula, is the three-phase voltage oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit; In the formula, is the three-phase current oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit; In the formula, is the oscillation coefficient of the instantaneous power at the mth oscillation frequency point of the jth thermal power unit; In the formula, is the excitation voltage oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit; In the formula, is the excitation current oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit; In the formula, is the oscillation coefficient of the engine speed at the mth oscillation frequency point of the jth thermal power unit; In the formula, is the tail speed oscillation coefficient of the mth oscillation frequency point of the jth thermal power unit.

7. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 6 is characterized in that: When it is determined that oscillation occurs and the oscillation amplitude of each monitoring data corresponding to the oscillation frequency point is not less than the set oscillation alarm amplitude constant value and the duration is not less than 1s, the startup time is accumulated and the oscillation time of each monitoring data corresponding to the oscillation frequency point is calculated using the following relationship: t k =t k-1 +Δ×a In the formula, τ k is the cumulative time value of each monitoring data corresponding to the oscillation frequency point under the current cumulative number k, τ k-1 is the cumulative time value of each monitoring data corresponding to the oscillation frequency point at the previous cumulative number k-1, α is the oscillation coefficient of each monitoring data corresponding to the oscillation frequency point at the current cumulative number k, Δ is the time difference between the current cumulative number k and the previous cumulative number k-1 for the fast Fourier transform algorithm, and the value of Δ is 100ms.

8. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 7 is characterized in that: When the oscillation coefficient of any monitoring data corresponding to the oscillation frequency point is less than 0.5 and the duration is not less than 2s, the oscillation time of any monitoring data corresponding to the oscillation frequency point is cleared; When the oscillation coefficient of any monitoring data corresponding to the oscillation frequency point is not less than 0.5 and the duration is not more than 1s, the time accumulation will not be started.

9. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 7 is characterized in that: When the oscillation time of each monitoring data corresponding to the oscillation frequency point is not less than the set oscillation alarm time value, an alarm is issued for the monitoring data at each monitoring point, including: when When the monitoring point is at the oscillation frequency f j_ssom The voltage under the alarm is alarmed, the alarm mark position is 3, where: is the voltage oscillation time of any phase at the mth oscillation frequency point of the jth thermal power unit; when When the monitoring point is at the oscillation frequency f j_ssom The current under the alarm is alarmed, the alarm mark position 2, where, is the oscillation time of any phase current at the mth oscillation frequency point of the jth thermal power unit; when When the monitoring point is at the oscillation frequency f j_ssom The instantaneous power under the alarm is alarmed, and the alarm flag position is 1, where: is the instantaneous power oscillation time of the mth oscillation frequency point of the jth thermal power unit; when When the monitoring point is at the oscillation frequency f j_ssom The excitation voltage under the alarm is alarmed, the alarm mark position is 4, where, is the excitation voltage oscillation time of the mth oscillation frequency point of the jth thermal power unit; when When the monitoring point is at the oscillation frequency f j_ssom The excitation current under the alarm is alarmed, the alarm mark position is 5, where, is the excitation current oscillation time of the mth oscillation frequency point of the jth thermal power unit; when When the monitoring point is at the oscillation frequency f j_ssom The nose speed alarm is given at the alarm position 6, where: is the oscillation time of the engine speed at the mth oscillation frequency point of the jth thermal power unit; when When the monitoring point is at the oscillation frequency f j_ssom The tail speed alarm is given at the alarm position 7, where: is the tail speed oscillation time of the mth oscillation frequency point of the jth thermal power unit.

10. The power plant sub-level super-synchronous multi-level early warning and shaft torsional vibration coordinated control method according to claim 9 is characterized in that: Warning rules, including: 1) Warning sign position 1 at the same time Then send a Level 5 warning instruction; 2) Warning sign position 2 at the same time If the alarm flag is set to a value other than 3, 4, 5, 6, or 7, a Level 4 warning command is sent. Then send a Level 4 warning instruction; 3) Warning sign position 3 at the same time If the alarm flag is a value other than 4, 5, 6, or 7, a Level 3 warning command is sent; if the alarm flag is in position 2, If the alarm flag is a value other than 3, 4, 5, 6, or 7, a Level 3 warning instruction is sent; 4) Warning sign position 4 at the same time If the alarm flag is a value other than 5, 6, or 7, a Level 2 warning command is sent; if the alarm flag is 5, If the alarm flag is a value other than 4, 6, or 7, a Level 2 warning command is sent; if the alarm flag is 4, Warning sign position 5 at the same time If the alarm flag is set to a value other than 6 or 7, a Level 2 warning command is sent; if the alarm flag is set to 3, If the alarm flag is a value other than 4, 5, 6, or 7, a Level 2 warning instruction is sent; 5) If the alarm mark is in position 7, a level 1 warning instruction is sent; if the alarm mark is in position 6, a level 1 warning instruction is sent; if the alarm mark is in position 6 and 7, a level 1 warning instruction is sent; if the alarm mark is in position 4 and 7, a level 1 warning instruction is sent; If the alarm flag is a value other than 5, 6, or 7, a Level 1 warning command is sent; if the alarm flag is 5, If the alarm flag is a value other than 4, 6, or 7, a Level 1 warning command is sent; if the alarm flag is 4, Warning sign position 5 at the same time If the alarm flag is a value other than 6 or 7, a Level 1 warning instruction is sent.

11. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 10 is characterized in that: The shafting natural frequency f of the jth thermal power unit within the subsynchronous frequency range ij As the natural frequency of the thermal power unit, i = 1, 2, ..., n, n is the number of oscillation modes; The deviations of the head speed oscillation frequency and tail speed oscillation frequency of the thermal power unit from the natural frequency are both f j_ssom With f ij The absolute value of the difference, the threshold value is 0.25Hz.

12. The power plant sub-level super-synchronous multi-level early warning and shaft torsional vibration coordinated control method according to claim 11 is characterized in that: Set the trip amplitude constant R of each thermal power unit under different oscillation modes ij_threshold_cut , trip time setting t ij_threshold_cut , coordinated control amplitude setting R ij_threshold_cc And the coordinated control time constant t ij_threshold_cc ; When the oscillation mode i is determined to have head torsional vibration, and the head speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Hj_ssom Not less than the trip amplitude setting R under oscillation mode i ij_threshold_cut , the ratio of the head speed oscillation amplitude to the trip amplitude constant under oscillation mode i is taken as the head torsional vibration trip coefficient under oscillation mode i; when it is determined that oscillation mode i occurs tail torsional vibration, and the tail speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Hj_ssom Not less than the trip amplitude setting R under oscillation mode i ij_threshold_cut , the ratio of the tail speed oscillation amplitude to the trip amplitude constant under oscillation mode i is taken as the tail torsional vibration trip coefficient under oscillation mode i; When the oscillation mode i is determined to have head torsional vibration, and the head speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit Hj_ssom Not less than the coordinated control amplitude constant R under oscillation mode i ij_threshold_cc When the ratio of the head speed oscillation amplitude to the coordinated control amplitude constant under oscillation mode i is taken as the head torsional vibration coordinated control coefficient under oscillation mode i; when it is determined that the tail torsional vibration occurs in oscillation mode i, the tail speed oscillation amplitude R of the mth oscillation frequency point of the jth thermal power unit is Hj_ssom Not less than the coordinated control amplitude constant R under oscillation mode i ij_threshold_cc When , the ratio of the tail speed oscillation amplitude to the coordinated control amplitude constant under oscillation mode i is taken as the tail torsional vibration coordinated control coefficient under oscillation mode i.

13. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 12 is characterized in that: When the head speed oscillation amplitude or tail speed oscillation amplitude of the mth oscillation frequency point of the jth thermal power unit is not less than the trip amplitude setting value under the oscillation mode i for a duration of not less than 1s, the start time is accumulated, and the head torsional vibration trip time or tail torsional vibration trip time of the oscillation mode i is calculated according to the following relationship: t ik =t ik-1 +Δ×a i In the formula, τ ik is the cumulative time value of the nose torsional vibration tripping or tail torsional vibration tripping of oscillation mode i under the current cumulative number k, τ ik-1 is the cumulative time value of the nose torsional vibration tripping or tail torsional vibration tripping of oscillation mode i under the previous cumulative number k-1, α i is the nose torsional vibration tripping coefficient or tail torsional vibration tripping coefficient of oscillation mode i under the current cumulative number k, Δ is the time difference between the current cumulative number k and the previous cumulative number k-1 for fast Fourier transform algorithm, and Δ is 100ms; When the oscillation amplitude of the head speed or the tail speed at the mth oscillation frequency point of the jth thermal power unit is not less than the coordinated control amplitude setting value under the oscillation mode i for a duration of not less than 1s, the start time is accumulated, and the head torsional vibration coordinated control time or the tail torsional vibration coordinated control time of the oscillation mode i is calculated according to the following relationship: t i ′ k =t i ′ k-1 +Δ×a i ′ In the formula, τ i ' k is the accumulated time value of the nose torsional vibration coordinated control or tail torsional vibration coordinated control of oscillation mode i under the current accumulated number k, τ i ' k-1 is the cumulative time value of the nose torsional vibration coordinated control or tail torsional vibration coordinated control of oscillation mode i under the previous cumulative number k-1, α i ′ is the nose torsional vibration coordination control coefficient or the tail torsional vibration coordination control coefficient of the oscillation mode i under the current cumulative number k, Δ is the time difference between the current cumulative number k and the previous cumulative number k-1 for the fast Fourier transform algorithm, and the value of Δ is 100ms.

14. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 13 is characterized in that: When the nose torsional vibration trip coefficient or the tail torsional vibration trip coefficient of oscillation mode i is less than 0.5 and the duration is not less than 2s, the nose torsional vibration trip time or the tail torsional vibration trip time of oscillation mode i is reset; When the nose torsional vibration coordination control coefficient or the tail torsional vibration coordination control coefficient of oscillation mode i is less than 0.5 and the duration is not less than 2s, the nose torsional vibration coordination control time or the tail torsional vibration coordination control time of oscillation mode i is reset; When the nose torsional vibration trip coefficient or tail torsional vibration trip coefficient of oscillation mode i is not less than 0.5 and the duration is not more than 1s, the time accumulation will not be started; When the nose torsional vibration coordination control coefficient or the tail torsional vibration coordination control coefficient of oscillation mode i is not less than 0.5 and the duration is not more than 1s, the time accumulation is not started.

15. The power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control method according to claim 14 is characterized in that: When the head torsional vibration tripping time or the tail torsional vibration tripping time of oscillation mode i is greater than the tripping time setting value and the first level warning command is sent, a thermal power unit tripping command is generated; When the nose torsional vibration coordination control time or the tail torsional vibration coordination control time of oscillation mode i is greater than the coordination control time set value, or when the first-level warning command is sent but the nose torsional vibration coordination control time or the tail torsional vibration coordination control time of oscillation mode i is less than the coordination control time set value, a request for coordination control command is sent to the superior.

16. A power plant level super-synchronous multi-level warning and shaft torsional vibration coordinated control system, characterized in that: include: An oscillation data processing module is used to obtain monitoring data at each monitoring point of each thermal power unit; Performing time-frequency domain transformation on the monitoring data of each thermal power unit to obtain a spectrum data set, using the spectrum data set of each thermal power unit to determine the oscillation frequency of each thermal power unit, and extracting the oscillation amplitude of each monitoring data corresponding to the oscillation frequency within a set range; Oscillation warning and torsional vibration judgment module, used to set the amplitude and time values ​​of the oscillation alarm of each monitoring data; When the oscillation amplitude of each monitoring data corresponding to the oscillation frequency is not less than the amplitude setting value of the oscillation alarm, it is determined that there is oscillation at the oscillation frequency at each monitoring point, and the ratio of the oscillation amplitude of each monitoring data corresponding to the oscillation frequency to the amplitude setting value of the oscillation alarm is used as the oscillation coefficient at the oscillation frequency at each monitoring point; when the duration of the oscillation amplitude of each monitoring data corresponding to the oscillation frequency being not less than the amplitude setting value of the oscillation alarm is not less than the set time, the start time is accumulated to obtain the oscillation time of each monitoring data corresponding to the oscillation frequency; When the oscillation time of each monitoring data corresponding to the oscillation frequency point is not less than the time setting value of the oscillation alarm, an alarm is issued for the monitoring data at each monitoring point; according to the natural frequency of each thermal power unit, the alarm signal of the monitoring data at each monitoring point, and the oscillation coefficient at the frequency corresponding to the oscillation frequency point at each monitoring point, five levels of early warning instructions are generated according to the early warning rules. When the first level early warning instruction is sent, the deviations of the head speed oscillation frequency and the tail speed oscillation frequency of each thermal power unit from the natural frequency are calculated; when the deviation of the head and / or tail speed oscillation frequency of the thermal power unit from the natural frequency is not greater than the threshold value, it is determined that the thermal power unit has head and / or tail torsional vibration; The torsional vibration control module is used to set the trip amplitude setting value, trip time setting value, coordinated control amplitude setting value and coordinated control time setting value of each thermal power unit under different oscillation modes; when the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency point of the thermal power unit is not less than the trip amplitude setting value under the oscillation mode and the duration is not less than the set time, the start time accumulation is started to calculate the head and / or tail torsional vibration trip time under the oscillation mode; When the head and / or tail speed oscillation amplitude corresponding to the oscillation frequency of the thermal power unit is not less than the coordinated control amplitude setting value under the oscillation mode and the duration is not less than the set time, the start time is accumulated to calculate the head or tail torsional vibration coordinated control time under the oscillation mode; when the head and / or tail torsional vibration tripping time of the oscillation mode is greater than the tripping time setting value and the first level early warning instruction is sent, a thermal power unit tripping instruction is generated; when the head and / or tail torsional vibration coordinated control time of the oscillation mode is greater than the coordinated control time setting value, or the first level early warning instruction is sent but the head and / or tail torsional vibration coordinated control time of the oscillation mode is less than the coordinated control time setting value, a request for coordinated control instruction is sent to the superior.

17. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 15.

18. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 15 are implemented.

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