CN112398144A - Primary frequency modulation dynamic cooperative control method of steam turbine regulating system - Google Patents
Primary frequency modulation dynamic cooperative control method of steam turbine regulating system Download PDFInfo
- Publication number
- CN112398144A CN112398144A CN202011283847.7A CN202011283847A CN112398144A CN 112398144 A CN112398144 A CN 112398144A CN 202011283847 A CN202011283847 A CN 202011283847A CN 112398144 A CN112398144 A CN 112398144A
- Authority
- CN
- China
- Prior art keywords
- frequency modulation
- frequency
- throttling
- primary
- unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 26
- 230000001105 regulatory effect Effects 0.000 title claims abstract description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 77
- 230000009471 action Effects 0.000 claims abstract description 55
- 238000006243 chemical reaction Methods 0.000 claims abstract description 29
- 238000005516 engineering process Methods 0.000 claims abstract description 28
- 238000009826 distribution Methods 0.000 claims abstract description 18
- 238000013178 mathematical model Methods 0.000 claims abstract description 14
- 238000005265 energy consumption Methods 0.000 claims abstract description 9
- 238000012360 testing method Methods 0.000 claims abstract description 8
- 230000002079 cooperative effect Effects 0.000 claims abstract description 3
- 230000008859 change Effects 0.000 claims description 17
- 230000033228 biological regulation Effects 0.000 claims description 13
- 230000000875 corresponding effect Effects 0.000 claims description 9
- 238000012886 linear function Methods 0.000 claims description 9
- 230000001276 controlling effect Effects 0.000 claims description 6
- 238000000605 extraction Methods 0.000 claims description 6
- 230000015271 coagulation Effects 0.000 claims description 5
- 238000005345 coagulation Methods 0.000 claims description 5
- 230000003247 decreasing effect Effects 0.000 claims description 5
- 230000000694 effects Effects 0.000 claims description 5
- 230000009467 reduction Effects 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 3
- 230000001960 triggered effect Effects 0.000 claims description 3
- 238000005520 cutting process Methods 0.000 claims description 2
- 238000001595 flow curve Methods 0.000 claims description 2
- 239000013589 supplement Substances 0.000 claims description 2
- 238000005457 optimization Methods 0.000 description 7
- 238000012797 qualification Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000005226 mechanical processes and functions Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
- H02J3/241—The oscillation concerning frequency
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Turbines (AREA)
Abstract
The invention relates to a primary frequency modulation dynamic cooperative control method of a steam turbine regulating system, which is characterized in that a condensing pump frequency conversion throttling and frequency modulation step technology are combined, part of steam medium used for low heat addition and exchange is recycled or released in cooperative control, a frequency modulation step is added outside a unit primary frequency modulation dead zone, performance curves of condensed water throttling and frequency modulation step under different working conditions are captured through a thermal state test, and a frequency modulation device is subjected to mathematical modeling; during the operation of the unit, according to the mathematical model, the frequency modulation capability of the condensed water throttling and frequency modulation step under each working condition is evaluated in real time, and the allocation is performed in advance by combining safety and economic indexes; and during primary frequency modulation action, each adjusting system performs instant cooperative action according to the distribution coefficient, and simultaneously gives consideration to unit safety and energy consumption indexes, and the adjusting depth of the adjusting system is adjusted in a cooperative manner. The invention can reduce the throttling loss to the maximum extent, increases the frequency modulation step outside the primary frequency modulation dead zone, can give consideration to the safety and energy consumption of the unit and ensures that the frequency modulation performance of the unit meets the requirement.
Description
Technical Field
The invention relates to the field of steam turbine regulating systems, in particular to a primary frequency modulation dynamic cooperative control method of a steam turbine regulating system.
Background
As a common problem of a unit in a full-cycle steam admission throttling steam distribution mode, the heat efficiency and the primary frequency modulation performance of the unit are difficult to be considered, in recent years, the network modulation highly emphasizes the primary frequency modulation performance of a power plant, the overall goal that the primary frequency modulation qualification rate reaches 75% is determined, the conventional primary frequency modulation technology is difficult to meet the requirement, and new technologies are continuously innovated, such as:
the prior art aims at the condensate throttling optimization technology. The system and the method for auxiliary control of primary frequency modulation of the full-cycle steam intake unit provided by CN201811279258.4 include a primary frequency modulation capability judgment unit and a condensed water throttling rapid load change control unit in the current state of the unit.
CN201910502699.4 provides a control method and a system for primary frequency modulation of a thermal generator set: acquiring a power grid frequency difference; judging whether the reduction amplitude of the power grid frequency exceeds a preset range or not according to the power grid frequency difference; if not, controlling the unit to perform primary frequency modulation based on the energy storage of the boiler; and if so, controlling the unit to perform primary frequency modulation based on the water supply bias optimization logic and the condensed water throttling optimization logic. Under the condition that the frequency of the power grid is greatly reduced, the frequency modulation precision and amplitude of primary frequency modulation are improved by two means of increasing the water supply quantity through water supply bias and reducing the condensate flow through condensate water throttling.
The prior art is particularly directed to frequency modulation dead zone techniques. CN201610074154.4 discloses an optimization control method and system for ensuring the action direction of primary frequency modulation, when a power grid frequency deviation signal delta f exceeds a frequency modulation dead zone +/-0.033 Hz specified by a national grid but does not reach a regional power grid dispatching check action frequency threshold, the coordination control and digital electro-hydraulic control of a unit respectively keep the original action direction and amplitude; when the power grid frequency deviation signal delta f not only exceeds the frequency modulation dead zone +/-0.033 Hz specified by the national grid, but also reaches the regional power grid dispatching and checking action frequency threshold, the unit coordination control and the digital electro-hydraulic control determine the locking increase or locking decrease according to the frequency difference while maintaining the due action amplitude. The invention can effectively ensure the change direction of the load of the unit during the primary frequency modulation action caused by the frequency fluctuation of the power grid, prevent the occurrence of the phenomenon of power back modulation, effectively improve the frequency modulation performance of the unit, improve the response accuracy of the thermal power unit to the primary frequency modulation dispatching, improve the action qualification rate of the thermal power unit and reduce the frequency fluctuation of the power grid system.
In addition, CN201910013512.4 is a method for improving DEH primary frequency modulation performance of a steam turbine generator unit, comprising S1, detecting the frequency difference of the steam turbine generator unit; s2, judging whether the frequency difference exceeds a frequency difference dead zone; s3, taking the given main steam flow as a target value of DEH primary frequency modulation; s4, converting the control quantity of the frequency signal change into an output signal of the main steam flow to the PID controller; s5, calculating the main steam flow control feedforward; and S6, converting the main steam flow instruction into the valve opening and the valve opening output by the main steam flow control feedforward to be superposed and summed to generate a comprehensive valve opening signal. The method for controlling the main steam flow by DEH closed loop enables the power generated by DEH primary frequency modulation of the steam turbine generator unit to comprise two parts: the power generated by the change of the main steam flow; the second is the synchronous transient power generated by the change of the rotating speed signal. The DEH primary frequency modulation performance of the steam turbine generator unit is recovered to be normal by controlling and adjusting the main steam flow.
The method belongs to the primary frequency modulation of a turbonator, but a condensate water throttling optimization technology and a small frequency difference processing technology need to be continuously innovated and developed.
Disclosure of Invention
The invention aims to seek the breakthrough of a unit primary frequency modulation small frequency difference processing technology on the basis of condensed water throttling optimization, thereby providing a primary frequency modulation dynamic cooperative control method of a steam turbine regulating system.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a primary frequency modulation dynamic cooperative control method of a steam turbine regulating system comprises condensing pump frequency conversion throttling, frequency modulation step and cooperative adjustment, combining condensing pump frequency conversion throttling and frequency modulation step technologies, recycling or releasing part of steam medium used for low heat addition and exchange in cooperative control, adding frequency modulation step outside a unit primary frequency modulation dead zone, capturing performance curves of condensed water throttling and frequency modulation step under different working conditions through thermal state tests, and performing mathematical modeling on a frequency modulation device
During the operation of the unit, according to the mathematical model, the frequency modulation capability of the condensed water throttling and frequency modulation step under each working condition is evaluated in real time, and the allocation is performed in advance by combining safety and economic indexes;
and during primary frequency modulation action, each adjusting system performs instant cooperative action according to the distribution coefficient, and simultaneously gives consideration to unit safety and energy consumption indexes, and the adjusting depth of the adjusting system is adjusted in a cooperative manner.
Further, the method specifically comprises the following steps:
s1, recovering or releasing part of steam medium for low heat addition and exchange by adopting a condensate pump variable frequency throttling technology, increasing or reducing heat energy for acting of a steam turbine, changing the load of a unit, and performing primary frequency modulation adjustment; by adopting a throttling regulation technology of double PID loop switching assisted with feedforward regulation, after primary frequency modulation action, a frequency conversion instruction of the condensate pump obtains corresponding output increase and decrease quantity according to the magnitude of frequency modulation power, so that the flow of condensate water changes according to the expected value, thereby changing the steam extraction quantity to achieve the preset frequency modulation effect;
and S2, taking the power grid frequency and the rotating speed signal as deviation input, calculating the power grid frequency difference, wherein the frequency difference exceeds a threshold primary frequency modulation action, and in order to increase the frequency modulation action amplitude with small frequency difference, the frequency modulation step is increased within 0.2RPM outside a unit primary frequency modulation dead zone and acts on the DEH side and the CCS side respectively.
Further, S1, a variable-frequency throttling technology of a condensate pump is adopted:
(1) adopting a coagulation pump to regulate the water level of the deaerator in a variable frequency manner, obtaining a deaerating water level control deviation through logic operation, and obtaining a coagulation pump variable frequency output frequency through PID operation for controlling the water level of the deaerator;
(2) before the primary frequency modulation of the condensed water is triggered, the variable frequency output of a condensing pump selects a deaerator water level regulation PID loop, and the condensed water throttling control PID loop tracks the output of the controller;
(3) after the primary frequency modulation action of the condensate water throttling, the condensate pump frequency conversion output selects a condensate water throttling control PID loop, and the frequency modulation instruction is increased or decreased on the basis of the original tracking value;
(4) setting the SP and PV values of the condensate throttling control PID to be 0, canceling the deviation regulation function of the condensate throttling control PID, and realizing the quick regulation of the variable frequency output through the feedforward action;
(5) the corresponding adjustment quantity of variable frequency output of the condensate pump is determined by the actual value of the frequency modulation power, the positive frequency modulation power represents that a primary frequency modulation action is carried out on the load increase, at the moment, the flow rate of condensate water needs to be reduced, and the negative change of a frequency conversion instruction is carried out; the frequency modulation power is negative, which represents that the primary frequency modulation action is in load reduction, at the moment, the condensate flow needs to be increased, and the frequency conversion instruction changes positively; the fixed values of the frequency modulation power and the frequency conversion increase and decrease quantity are captured and modeled through a thermal state test and are realized by a linear function block F (X1);
(6) after the primary frequency modulation action of the condensed water, the instantaneous change of the flow of the condensed water generates huge disturbance to the regulating system, and the disturbance amount is limited within the safe range which can be borne by the system;
(7) and after the primary frequency modulation action of the condensed water is finished for 1min, the variable frequency output instruction of the condensing pump is restored to the frequency value before the frequency modulation action at a certain speed, and then the frequency is restored to the liquid level PID loop of the deaerator.
Further, the implementation method of S2 includes:
(1) assuming that the unit rotation speed unequal rate is omega, calculating a linear function relationship F (X2) =3000 omega/100 =30 omega of slip and comprehensive valve position variation according to the definition, wherein the slip is X in 0.2RPM outside a primary frequency modulation dead zone, and the frequency modulation step quantity M = X2.2/F (X2) = 0.2= X11/30 omega;
note: the rotating speed unequal rate: under the condition that the mechanical power of the unit is constant, the percentage of the ratio of the difference between the empty load rotating speed (r 1) and the full load rotating speed (r 2) to the rated rotating speed is called the rotating speed unequal rate of the regulating system, namely omega = (r 1-r 2)/3000, and the percentage is expressed.
Assuming that the rotational speed non-constant rate is 4.5, the unit is increasing from the empty load to the full load, and when the mechanical power of the unit is constant, the rotational speed variation is 3000 ω =3000 ω 4.5% =135RPM, but the mechanical function must be increased in order to maintain the rotational speed constant, the main approach is to increase the integrated valve position opening, the integrated valve position opening variation is 100% at the maximum, and the slope relationship between the slip and the integrated valve position variation, that is, F (X2) =3000 ω/100= 3000 4.5%/100=1.35, can be obtained.
The following calculates the fm step M1 at 0.2RPM outside the primary fm dead band (i.e., 2.2RPM slip). Since the slip dead zone is 2RPM, the maximum step value is calculated under the condition that no rotation speed dead zone is assumed, i.e., 2.2/M1= F (X2), M1=2.2/F (X2).
The primary frequency modulation dead zone is required to be 2RPM, the primary frequency modulation does not act within 2RPM of the rotation difference, and the frequency modulation step value is 0 when 0RPM (namely the rotation difference is 2 RPM) is outside the primary frequency modulation dead zone.
The calculated relationship of the frequency modulation step quantity of the dead zone external rotation difference X (2 RPM dead zone is subtracted) within 2RPM-2.2RPM can be obtained: (M1-0)/0.2 = M/(X-0),
from the above, it follows: m = X × 2.2/F (X2) × 0.2= X × 11/30 ω.
(2) The frequency modulation step quantity M acts on the comprehensive valve position instruction output in a superposition mode at the DEH side, and the DEH high-regulation valve is actuated through a valve flow curve, so that the actuation amplitude of the DEH high-regulation valve is improved;
(3) the frequency modulation step quantity M acts on the steam turbine master control of the CCS in a feedforward mode, and the comprehensive valve position output of the coordination side is obtained through PID operation, so that the CCS is prevented from being reversely adjusted.
Further, the specific mathematical modeling comprises the following steps:
s1, under the working conditions of 50% Po, 75% Po and 100% Po loads of a unit, automatically cutting off a variable frequency water level of a condensate pump, increasing and decreasing variable frequency instructions of the condensate pump at an operation end, quantitatively changing the flow of condensate water, observing instantaneous changes of the unit load, analyzing the contribution of frequency modulation power in a condensate water saving environment, forming a linear function curve F (X3) of the condensate water saving amount and the frequency modulation power at a specific load section, and establishing a mathematical model of the primary frequency modulation performance of the condensate water saving;
s2, under the load working conditions of 50% Po, 75% Po and 100% Po of the unit, the unit is cut off in a coordinated mode, DEH is cut off automatically, frequency modulation steps are applied to an operation end, the contribution amount of the frequency modulation steps of each load section to frequency modulation power is analyzed, a linear function curve F (X4) is formed, and a mathematical model of the frequency modulation step primary frequency modulation performance is established;
s3, calculating frequency modulation power demand under different frequency differences in real time according to the unequal rates of the unit rotating speeds; frequency modulation power demand quantity ^ P = (1000 revolution difference)/(3000 omega), and a mathematical model of the frequency modulation power demand quantity under the variable working condition is established.
And S4, pre-distributing the frequency modulation power in different load sections, namely ^ P = α 1 × F (X3) + α 2 × F (X4), wherein the influence of the throttling of the condensed water on the DEH frequency modulation device is minimum, namely the default α 1 × F (X3) in the mathematical model is the maximum value, and α 2 × F (X4) is a supplement value, so that distribution coefficients α 1 and α 2 are calculated, and the frequency modulation power pre-distribution mathematical model is obtained.
S5, judging primary frequency modulation action according to the frequency difference of the power grid, wherein during the action, condensed water is throttled, and the frequency modulation step acts according to pre-distribution coefficients alpha 1 and alpha 2 to ensure that the frequency modulation power meets the primary frequency modulation requirement.
The invention adopts the variable-frequency throttling technology of the condensate pump, reduces the steam extraction quantity of the steam turbine, and improves the working capacity of the working medium, thereby quickly changing the load of the unit. Compared with CN201910502699.4, the invention discloses a variable-frequency throttling technology for a condensate pump, which takes variable-frequency regulation of the condensate pump as a main body, the water-feeding regulating valve of a deaerator is kept fully open, no throttling loss is caused, the condensate water throttling is realized on the premise of not increasing the power consumption of the condensate pump, and the variable-frequency throttling technology has considerable energy-saving effect; after the primary frequency modulation action, the frequency conversion instruction of the condensate pump obtains the corresponding output increase and decrease amount according to the magnitude of the frequency modulation power, so that the condensate flow changes according to the expected value, thereby changing the steam extraction amount to achieve the preset frequency modulation effect.
The invention relates to an optimization control method and a system for ensuring the direction of primary frequency modulation action, which take the frequency and the rotating speed signals of a power grid as deviation input, calculate the frequency difference of the power grid, increase the frequency modulation step within 0.2RPM outside a unit primary frequency modulation dead zone for increasing the amplitude of the small frequency difference frequency modulation action, and respectively act on a DEH side and a CCS side, compared with CN 201610074154.4.
The invention has the beneficial effects that: the system adopts a condensate throttling technology to quickly change the load of the unit, primary frequency modulation adjustment is carried out, a condensate pump frequency conversion adjustment technology is used for changing the flow of condensate, a water feeding adjusting valve of the deaerator is kept fully opened, and throttling loss can be reduced to the maximum extent. And frequency modulation step is added outside the unit primary frequency modulation dead zone and acts on a DEH side, the frequency modulation quantity is superposed on a comprehensive valve position instruction, the action amplitude of the unit high modulation is improved, the frequency modulation quantity acts on a CCS side, and the frequency modulation quantity acts on the steam turbine master control of the CCS in a feedforward mode to prevent the CCS from reversely modulating. During the operation of the unit, the frequency modulation capability of the condensed water throttling and frequency modulation step under the working condition is evaluated in real time according to the performance curve, distribution is preformed, and each regulating system acts in a real-time and coordinated mode according to the distribution coefficient during primary frequency modulation action, so that the unit frequency modulation performance is ensured to meet the requirement while the unit safety and energy consumption are considered.
In conclusion, the invention can dynamically evaluate the safety and the economy of the unit in the frequency modulation process according to different operation conditions, and cooperatively adjust the adjustment depth of the primary frequency modulation function and the energy consumption and the frequency modulation performance of the unit; the frequency modulation technology can effectively solve the primary frequency modulation technical problem of the problem of single or coexistence of source networks, has universality and high efficiency, has the average primary frequency modulation qualification rate of over 85 percent, and can be popularized and applied to the frequency modulation control of various large-scale thermal generator sets.
Drawings
FIG. 1 is a block diagram of the variable frequency throttling logic of the coagulation pump of the present invention;
fig. 2 is a frequency modulated step logic block diagram of the present invention.
Detailed Description
A primary frequency modulation dynamic cooperative control method of a steam turbine regulating system comprises variable frequency throttling and frequency modulation step of a condensing pump, and specifically comprises the following steps:
s1, combining variable-frequency throttling and frequency-modulation step-step technology of the condensate pump, capturing performance curves of the variable-frequency throttling and frequency-modulation step-step technology of the condensate pump under various working conditions through tests, dynamically evaluating the safety and the economy of the unit, considering the energy consumption and the frequency-modulation performance of the unit, and cooperatively adjusting the adjustment depth of the unit;
s2, adopting the condensed water throttling technology, rapidly recovering or releasing part of steam medium for low heat exchange, increasing or reducing heat energy for the work of the steam turbine, rapidly changing the load of the unit, and performing primary frequency modulation adjustment.
The condensing pump frequency conversion adjustment technology changes the flow of condensed water, reduces the steam extraction amount of a steam turbine, takes the condensing pump frequency conversion adjustment as a main body, and a water feeding adjusting door of a deaerator is kept fully opened, so that the throttling loss can be reduced to the maximum extent, and the throttling of the condensed water is realized on the premise of not increasing the power consumption of the condensing pump.
Increasing frequency modulation step within 0.2RPM outside the unit primary frequency modulation dead zone, converting the original step amplitude by the unequal rate of the rotating speed, acting on the frequency modulation action modes of the traditional DEH and CCS, acting on the DEH side, and superposing the frequency modulation quantity on a comprehensive valve position instruction to improve the action amplitude of the unit high modulation; acting on the CCS side, the frequency modulation quantity acts on the steam turbine main control of the CCS in a feedforward mode, and the CCS is prevented from being reversely modulated.
The performance curves of condensate throttling and frequency modulation step under different working conditions are captured through a thermal state test, the frequency modulation capability of the condensate throttling and frequency modulation step under the working conditions is evaluated in real time according to the performance curves during the running of the unit, the distribution is performed in advance by combining the safety and the economy, and each regulating system acts in a real-time cooperation mode according to the distribution coefficient during the primary frequency modulation action, so that the unit frequency modulation performance is ensured to meet the requirements while the safety and the energy consumption of the unit are considered.
As shown in figure 1, the main functions of the condensate pump frequency conversion throttling and condensate water throttling primary frequency modulation technology are mainly technical means of double PID loop switching and feed-forward regulation, after primary frequency modulation action, a condensate pump frequency conversion instruction obtains corresponding output increase and decrease according to the frequency modulation power, so that the condensate water flow changes according to the expected value, the steam extraction amount is changed, and the preset frequency modulation effect is achieved.
(1) Before the primary frequency modulation of the condensed water is triggered, the frequency conversion output of the condensing pump selects a deaerator water level regulation PID loop, and the condensed water throttling control PID loop tracks the output of the controller.
(2) After the primary frequency modulation action of the condensed water throttling, the condensed pump frequency conversion output selects the condensed water throttling control PID loop, and the frequency modulation instruction is increased or decreased on the basis of the original tracking value.
(3) The SP PV value of the condensate throttling control PID is set to be 0, the deviation adjusting function of the condensate throttling control PID is cancelled, and the fast adjustment of the variable frequency output is realized through the feedforward action.
(4) The corresponding adjustment quantity of variable frequency output of the condensate pump is determined by the actual value of the frequency modulation power, the positive frequency modulation power represents that a primary frequency modulation action is carried out on the load increase, at the moment, the flow rate of condensate water needs to be reduced, and the negative change of a frequency conversion instruction is carried out; the frequency modulation power is negative, which means that the primary frequency modulation action is in load reduction, at the moment, the condensate flow needs to be increased, and the frequency conversion instruction changes positively. The corresponding relation between the frequency modulation power and the frequency conversion increment and decrement fixed value is realized by a function block F (X).
(5) After the primary frequency modulation action of the condensed water, the instantaneous change of the flow of the condensed water generates huge disturbance to the regulating system, the disturbance amount is limited in a safe range which can be borne by the system, the maximum frequency change amplitude of the primary frequency modulation of the condensed water in the State-pacifying power plant is 5HZ, and the corresponding load maximum increment is about 13.67 MW.
(6) And after the primary frequency modulation action of the condensed water is finished for 1min, the variable frequency output instruction of the condensing pump is restored to the frequency value before the frequency modulation action at a certain speed, and then the frequency is restored to the liquid level PID loop of the deaerator.
The 'condensed water primary frequency modulation action signal' needs to be delayed by one DCS scanning period to be used as a judgment signal of the switching functional block. IN the same operation period, the operation sequence of each function block of the DCS is divided IN sequence, if the operation sequence of the signal of the switching block IN1 lags behind the switching judgment signal, the switching block locks a non-target value (namely 0) before the frequency modulation power changes, and finally the frequency conversion output signal of the condensate pump is kept unchanged, so that the condensate water throttling primary frequency modulation function is influenced.
As shown in fig. 2, the rotation speed non-constant rate is ω at the time of the frequency modulation step, and by definition, a linear function relationship F (X2) =3000 × ω/100=30 ω between the slip and the integrated valve position variation can be calculated, the slip in 0.2RPM outside the primary frequency modulation dead zone is X, and the frequency modulation step amount M = X2.2/F (X2) × 0.2= X11/30 ω.
Through a thermal state test, performance curves of condensate throttling and frequency modulation step change under various working conditions are captured, distribution is conducted in advance, and when a frequency modulation action is conducted for the first time, the action can be conducted according to a distribution coefficient.
The condensate throttling technology is adopted to quickly change the load of the unit, primary frequency modulation adjustment is carried out, the condensate pump frequency conversion adjustment technology is adopted to change the flow of condensate, the water feeding adjusting valve of the deaerator is kept fully opened, and throttling loss can be reduced to the maximum extent. And frequency modulation step is added outside the unit primary frequency modulation dead zone and acts on a DEH side, the frequency modulation quantity is superposed on a comprehensive valve position instruction, the action amplitude of the unit high modulation is improved, the frequency modulation quantity acts on a CCS side, and the frequency modulation quantity acts on the steam turbine master control of the CCS in a feedforward mode to prevent the CCS from reversely modulating. During the operation of the unit, the frequency modulation capability of the condensed water throttling and frequency modulation step under the working condition is evaluated in real time according to the performance curve, distribution is preformed, and each regulating system acts in a real-time and coordinated mode according to the distribution coefficient during primary frequency modulation action, so that the unit frequency modulation performance is ensured to meet the requirement while the unit safety and energy consumption are considered.
When the method is applied to the production of the applicant, the average primary frequency modulation yield is increased from originally less than 20% to 85.83%, the average primary frequency modulation yield far exceeds the average level of the industry, statistics shows that the average annual exemption assessment amount is 1443.12 ten thousand yuan, and the method has considerable economic benefit.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent modifications made by the present invention and the contents of the drawings or directly or indirectly applied to the related technical fields are included in the scope of the present invention.
Claims (5)
1. A primary frequency modulation dynamic cooperative control method of a steam turbine regulating system comprises condensing pump frequency conversion throttling and frequency modulation step, and is characterized in that condensing pump frequency conversion throttling and frequency modulation step technology are combined, part of steam medium used for low heat addition and exchange is recycled or released in cooperative control, meanwhile, frequency modulation step is added outside a unit primary frequency modulation dead zone, performance curves of condensed water throttling and frequency modulation step under different working conditions are captured through thermal state tests, and mathematical modeling is carried out on a frequency modulation device;
during the operation of the unit, according to the mathematical model, the frequency modulation capability of the condensed water throttling and frequency modulation step under each working condition is evaluated in real time, and the allocation is performed in advance by combining safety and economic indexes;
and during primary frequency modulation action, each adjusting system performs instant cooperative action according to the distribution coefficient, and simultaneously gives consideration to unit safety and energy consumption indexes, and the adjusting depth of the adjusting system is adjusted in a cooperative manner.
2. The primary frequency modulation dynamic cooperative control method of the steam turbine regulating system according to claim 1, characterized by comprising the following steps:
s1, recovering or releasing part of steam medium for low heat addition and exchange by adopting a condensate pump variable frequency throttling technology, increasing or reducing heat energy for acting of a steam turbine, changing the load of a unit, and performing primary frequency modulation adjustment; by adopting a throttling regulation technology of double PID loop switching assisted with feedforward regulation, after primary frequency modulation action, a frequency conversion instruction of the condensate pump obtains corresponding output increase and decrease quantity according to the magnitude of frequency modulation power, so that the flow of condensate water changes according to the expected value, thereby changing the steam extraction quantity to achieve the preset frequency modulation effect;
and S2, taking the power grid frequency and the rotating speed signal as deviation input, calculating the power grid frequency difference, wherein the frequency difference exceeds a threshold primary frequency modulation action, and in order to increase the frequency modulation action amplitude with small frequency difference, the frequency modulation step is increased within 0.2RPM outside a unit primary frequency modulation dead zone and acts on the DEH side and the CCS side respectively.
3. The primary frequency modulation dynamic cooperative control method of the steam turbine regulating system according to claim 1, characterized in that S1. a condensing pump frequency conversion throttling technology is adopted:
(1) adopting a coagulation pump to regulate the water level of the deaerator in a variable frequency manner, obtaining a deaerating water level control deviation through logic operation, and obtaining a coagulation pump variable frequency output frequency through PID operation for controlling the water level of the deaerator;
(2) before the primary frequency modulation of the condensed water is triggered, the variable frequency output of a condensing pump selects a deaerator water level regulation PID loop, and the condensed water throttling control PID loop tracks the output of the controller;
(3) after the primary frequency modulation action of the condensate water throttling, the condensate pump frequency conversion output selects a condensate water throttling control PID loop, and the frequency modulation instruction is increased or decreased on the basis of the original tracking value;
(4) setting the SP and PV values of the condensate throttling control PID to be 0, canceling the deviation regulation function of the condensate throttling control PID, and realizing the quick regulation of the variable frequency output through the feedforward action;
(5) the corresponding adjustment quantity of variable frequency output of the condensate pump is determined by the actual value of the frequency modulation power, the positive frequency modulation power represents that a primary frequency modulation action is carried out on the load increase, at the moment, the flow rate of condensate water needs to be reduced, and the negative change of a frequency conversion instruction is carried out; the frequency modulation power is negative, which represents that the primary frequency modulation action is in load reduction, at the moment, the condensate flow needs to be increased, and the frequency conversion instruction changes positively; the fixed values of the frequency modulation power and the frequency conversion increase and decrease quantity are captured and modeled through a thermal state test and are realized by a linear function block F (X1);
(6) after the primary frequency modulation action of the condensed water, the instantaneous change of the flow of the condensed water generates huge disturbance to the regulating system, and the disturbance amount is limited within the safe range which can be borne by the system;
(7) and after the primary frequency modulation action of the condensed water is finished for 1min, the variable frequency output instruction of the condensing pump is restored to the frequency value before the frequency modulation action at a certain speed, and then the frequency is restored to the liquid level PID loop of the deaerator.
4. The primary frequency modulation dynamic cooperative control method of a steam turbine regulating system according to claim 1, characterized in that the implementation method of S2 comprises the following steps:
(1) assuming that the unit rotation speed unequal rate is omega, calculating a linear function relationship F (X2) =3000 omega/100 =30 omega of slip and comprehensive valve position variation according to the definition, wherein the slip is X in 0.2RPM outside a primary frequency modulation dead zone, and the frequency modulation step quantity M = X2.2/F (X2) = 0.2= X11/30 omega;
(2) the frequency modulation step quantity M acts on the comprehensive valve position instruction output in a superposition mode at the DEH side, and the DEH high-regulation valve is actuated through a valve flow curve, so that the actuation amplitude of the DEH high-regulation valve is improved;
(3) the frequency modulation step quantity M acts on the steam turbine master control of the CCS in a feedforward mode, and the comprehensive valve position output of the coordination side is obtained through PID operation, so that the CCS is prevented from being reversely adjusted.
5. The primary frequency modulation dynamic cooperative control method of a steam turbine regulating system according to claim 1, wherein the concrete mathematical modeling comprises the steps of:
(1) under the working conditions of 50% Po, 75% Po and 100% Po loads of the unit, automatically cutting off the variable frequency water level of the condensate pump, increasing and decreasing the variable frequency instruction of the condensate pump at an operation end, quantitatively changing the flow of condensate water, observing the instantaneous change of the load of the unit, analyzing the contribution of frequency modulation power in the condensate water throttling environment, forming a linear function curve F (X3) of the condensate water throttling flow and the frequency modulation power at a specific load section, and establishing a mathematical model of the primary frequency modulation performance of the condensate water throttling;
(2) under the load working conditions of 50% Po, 75% Po and 100% Po of the unit, the unit is cut off in a coordinated mode, DEH is cut off automatically, frequency modulation steps are applied to an operation end, the contribution amount of the frequency modulation steps of each load section to frequency modulation power is analyzed, a linear function curve F (X4) is formed, and a mathematical model of the primary frequency modulation performance of the frequency modulation steps is established;
(3) establishing a mathematical model according to the unequal rate of the rotating speed of the unit, and calculating the frequency modulation power demand under different frequency differences in real time; frequency modulation power demand quantity ^ P = (1000 × slip)/(3000 ω), and a mathematical model of the frequency modulation power demand quantity under the variable working condition is established;
(4) pre-distributing the frequency modulation power in different load segments, namely ^ P = alpha 1 × F (X3) + alpha 2 × F (X4), and calculating distribution coefficients alpha 1 and alpha 2 and the pre-distribution mathematical model of the frequency modulation power because the throttling of the condensed water has minimum influence on the DEH frequency modulation device, namely the default alpha 1 × F (X3) in the mathematical model is the maximum value and the default alpha 2 × F (X4) is the supplement value;
(5) and judging primary frequency modulation action according to the frequency difference of the power grid, wherein during the action, the condensed water is throttled, and the frequency modulation step acts according to pre-distribution coefficients alpha 1 and alpha 2, so that the frequency modulation power meets the primary frequency modulation requirement.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011283847.7A CN112398144B (en) | 2020-11-17 | 2020-11-17 | Primary frequency modulation dynamic cooperative control method of steam turbine regulating system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011283847.7A CN112398144B (en) | 2020-11-17 | 2020-11-17 | Primary frequency modulation dynamic cooperative control method of steam turbine regulating system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112398144A true CN112398144A (en) | 2021-02-23 |
| CN112398144B CN112398144B (en) | 2024-08-30 |
Family
ID=74600926
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011283847.7A Active CN112398144B (en) | 2020-11-17 | 2020-11-17 | Primary frequency modulation dynamic cooperative control method of steam turbine regulating system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112398144B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113541204A (en) * | 2021-08-10 | 2021-10-22 | 上海电力大学 | Self-adaptive adjustment method and system for full-load peak shaving of coal-fired generator set |
| CN114583719A (en) * | 2022-03-21 | 2022-06-03 | 国电内蒙古东胜热电有限公司 | AGC primary frequency modulation control logic optimization analysis system of thermal power plant |
| CN115717554A (en) * | 2022-11-18 | 2023-02-28 | 中广核研究院有限公司 | Robustness adjusting method and system of steam turbine rotating speed adjusting system |
| CN116454913A (en) * | 2023-03-22 | 2023-07-18 | 华能国际电力股份有限公司济宁电厂 | Primary frequency modulation system and method based on variable frequency adjustment and lifting of coagulation pump |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030010037A1 (en) * | 2001-07-13 | 2003-01-16 | Pecom Energia, S.A. | Primary frequency regulation method in combined-cycle steam turbines |
| CN105678105A (en) * | 2016-04-08 | 2016-06-15 | 国网浙江省电力公司电力科学研究院 | Online evaluating method and device for primary frequency modulation capacity of turbine |
| CN106065791A (en) * | 2016-07-26 | 2016-11-02 | 国网浙江省电力公司电力科学研究院 | The control method of a kind of thermal power generation unit primary frequency modulation and system |
| CN106845639A (en) * | 2016-12-27 | 2017-06-13 | 国网浙江省电力公司电力科学研究院 | Steam turbine valve based on neutral net lifts the Potential Prediction method of unit load |
| CN107024914A (en) * | 2017-06-16 | 2017-08-08 | 国网河南省电力公司电力科学研究院 | Fired power generating unit condensate throttling participates in primary frequency modulation control system and operation method |
| CN107905852A (en) * | 2017-11-02 | 2018-04-13 | 国网安徽省电力公司电力科学研究院 | A kind of method of the wide load condensate throttling frequency modulation of fired power generating unit |
| CN108802609A (en) * | 2018-04-16 | 2018-11-13 | 国网福建省电力有限公司 | A kind of primary frequency modulation performance lifting test method considering nuclear power generating sets tolerance |
| JP2019115249A (en) * | 2017-12-25 | 2019-07-11 | 赫普科技発展（北京）有限公司 | Method, apparatus, and system for frequency modulation in power grid |
-
2020
- 2020-11-17 CN CN202011283847.7A patent/CN112398144B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030010037A1 (en) * | 2001-07-13 | 2003-01-16 | Pecom Energia, S.A. | Primary frequency regulation method in combined-cycle steam turbines |
| CN105678105A (en) * | 2016-04-08 | 2016-06-15 | 国网浙江省电力公司电力科学研究院 | Online evaluating method and device for primary frequency modulation capacity of turbine |
| CN106065791A (en) * | 2016-07-26 | 2016-11-02 | 国网浙江省电力公司电力科学研究院 | The control method of a kind of thermal power generation unit primary frequency modulation and system |
| CN106845639A (en) * | 2016-12-27 | 2017-06-13 | 国网浙江省电力公司电力科学研究院 | Steam turbine valve based on neutral net lifts the Potential Prediction method of unit load |
| CN107024914A (en) * | 2017-06-16 | 2017-08-08 | 国网河南省电力公司电力科学研究院 | Fired power generating unit condensate throttling participates in primary frequency modulation control system and operation method |
| CN107905852A (en) * | 2017-11-02 | 2018-04-13 | 国网安徽省电力公司电力科学研究院 | A kind of method of the wide load condensate throttling frequency modulation of fired power generating unit |
| JP2019115249A (en) * | 2017-12-25 | 2019-07-11 | 赫普科技発展（北京）有限公司 | Method, apparatus, and system for frequency modulation in power grid |
| CN108802609A (en) * | 2018-04-16 | 2018-11-13 | 国网福建省电力有限公司 | A kind of primary frequency modulation performance lifting test method considering nuclear power generating sets tolerance |
Non-Patent Citations (1)
| Title |
|---|
| 张秋生;梁华;: "协调控制系统稳定性的影响因素及考核方法", 电力技术, no. 05, 15 October 2008 (2008-10-15) * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113541204A (en) * | 2021-08-10 | 2021-10-22 | 上海电力大学 | Self-adaptive adjustment method and system for full-load peak shaving of coal-fired generator set |
| CN114583719A (en) * | 2022-03-21 | 2022-06-03 | 国电内蒙古东胜热电有限公司 | AGC primary frequency modulation control logic optimization analysis system of thermal power plant |
| CN114583719B (en) * | 2022-03-21 | 2024-04-19 | 国电内蒙古东胜热电有限公司 | AGC primary frequency modulation control logic optimization analysis system of thermal power plant |
| CN115717554A (en) * | 2022-11-18 | 2023-02-28 | 中广核研究院有限公司 | Robustness adjusting method and system of steam turbine rotating speed adjusting system |
| CN116454913A (en) * | 2023-03-22 | 2023-07-18 | 华能国际电力股份有限公司济宁电厂 | Primary frequency modulation system and method based on variable frequency adjustment and lifting of coagulation pump |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112398144B (en) | 2024-08-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112398144A (en) | Primary frequency modulation dynamic cooperative control method of steam turbine regulating system | |
| CN104865830B (en) | Dual-intelligent-optimization control method for unit load | |
| CN106773681A (en) | A kind of dum boiler fired power generating unit primary frequency modulation controls optimization method | |
| CN103216282B (en) | Thermal power generating unit loading control system and method based on continuously adjustable back pressure | |
| CN103244397B (en) | Frequency conversion circulating water pump Optimum operating control method | |
| CN105652663B (en) | A method of the sliding pressure curve depth optimization differentiated based on loading zone | |
| CN111255529B (en) | Rapid response automatic power generation control system and method during operation of heat supply cylinder cutting unit | |
| Jain et al. | Three area power system load frequency control using fuzzy logic controller | |
| CN113452092B (en) | Control method for improving AGC comprehensive frequency modulation performance index of thermal power generating unit | |
| CN111092441A (en) | Method and system for controlling regional load frequency of pumped storage power station | |
| CN112361324A (en) | Energy-saving and consumption-reducing method for condensate pump of double reheating unit | |
| CN113448248A (en) | Intelligent control method for flexibility and deep peak regulation of thermal power generating unit | |
| CN113483319A (en) | Variable-frequency energy-saving optimization control system and method for condensate pump of thermal power generating unit | |
| CN105896616A (en) | Thermal power generation unit real-time dispatching requirement determination method considering maximum new energy utilization | |
| CN110376895A (en) | A kind of fired power generating unit control method for coordinating based on layering constrained predictive control | |
| CN109915216A (en) | A kind of thermal power plant unit control steam extraction frequency modulation system and adjusting method in short-term | |
| CN107989665B (en) | Three-side primary frequency modulation control method and system for heat supply generator set | |
| JP2022047022A (en) | Power system stabilization system and power system stabilization method | |
| CN108131238A (en) | A kind of New PID Control method for inhibiting water hammer pressure fluctuation | |
| CN116292063A (en) | Pipeline type asynchronous hydroelectric generation control system and control strategy thereof | |
| CN117040031A (en) | Control method for participating in primary frequency modulation of power grid by variable-speed pumped storage unit | |
| CN115031225A (en) | Steam heating network energy storage auxiliary peak regulation control method, system, equipment and medium | |
| CN116154804A (en) | Fan-water turbine primary frequency modulation control method considering standby flexibility | |
| CN215718991U (en) | High-efficient peak regulation steam turbine system | |
| CN113819070B (en) | Variable-frequency optimization energy-saving method and system for condensate pump of steam turbine unit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |