CN111900741A - Power grid rapid frequency modulation device and method - Google Patents
Power grid rapid frequency modulation device and method Download PDFInfo
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- 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
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- 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
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- 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
Abstract
The invention discloses a device and a method for quickly modulating frequency of a power grid, which solve the problems of low response speed, low power adjustment accuracy and small adjustment range of the conventional device and method. The apparatus, comprising: the power grid frequency calculation module is used for calculating the instantaneous frequency of a power grid; the frequency averaging module is used for calculating a short-time frequency average value and a long-time frequency average value; the frequency difference calculation module is used for obtaining a frequency difference value; the frequency difference filtering module is used for outputting a frequency difference filtering value; the frequency difference adjusting module is used for determining an adjusting coefficient, receiving the frequency difference filtering value and multiplying the frequency difference filtering value by the adjusting coefficient to obtain a power adjusting value; the power adjustment control module is used for receiving the frequency difference value, and when the frequency difference value is larger than the fluctuation threshold, firstly sending a reset signal to the frequency difference filtering module and then sending a starting instruction; and the power adjusting module is used for receiving the power adjusting value, and adjusting the output power of the power station by using the power adjusting value after receiving the starting instruction. The method is used for the device. The invention realizes the rapid frequency adjustment technology of the power grid.
Description
Technical Field
The invention relates to the field of power grids, in particular to a device and a method for quickly modulating frequency of a power grid.
Background
In order to solve the problem of quick response of the power grid frequency, the national power grid provides a quick frequency modulation problem for new energy grid connection, and a new energy power station requiring grid connection has a quick frequency modulation technology, and the core of the technology is as follows: firstly, when a power station is connected to the grid for power generation, 10% of power needs to be reserved; and secondly, the power station can accurately detect the frequency of the power grid, and when the frequency is higher and lower by 0.1Hz, the power station automatically adjusts the output power. The existing fast frequency modulation technology has the following defects: firstly, a green energy power station must keep a certain amount of generated electricity, which causes energy waste; secondly, within the deviation of plus or minus 0.1Hz, the new energy power station cannot participate in rapid adjustment, so that the frequency of the power grid is unstable; thirdly, the deviation is positive and negative 0.1-0.2 Hz, the output power of the new energy power station changes linearly, the adjustment form is single, and the power adjustment cannot be accurately carried out.
Disclosure of Invention
The invention provides a device and a method for quickly modulating frequency of a power grid, which solve the problems of low response speed, low power adjustment accuracy and small adjustment range of the conventional device and method.
In order to solve the problems, the invention is realized as follows:
the embodiment of the invention provides a power grid rapid frequency modulation device, which comprises: the power grid frequency calculation module is used for calculating the instantaneous frequency of a power grid; the frequency averaging module is used for receiving the instantaneous frequency of the power grid and calculating a short-time frequency average value and a long-time frequency average value; the frequency difference calculation module is used for receiving the long-time frequency mean value and the short-time frequency mean value and subtracting the long-time frequency mean value and the short-time frequency mean value to obtain a frequency difference value; the frequency difference filtering module is used for receiving the frequency difference value, outputting a frequency difference filtering value, receiving a reset signal sent by the power adjustment control module and resetting the time constant; the frequency difference adjusting module is used for receiving the frequency difference value, determining an adjusting coefficient according to the size of the frequency difference value and a preset time constant of the short-time frequency average value, receiving the frequency difference filtering value and multiplying the frequency difference filtering value by the adjusting coefficient to obtain a power adjusting value; the power adjustment control module is used for receiving the frequency difference value, and when the frequency difference value is larger than a fluctuation threshold, firstly sending a reset signal to the frequency difference filtering module and then sending a starting instruction to the power adjustment module; and the power adjusting module is used for receiving the power adjusting value, and adjusting the output power of the power station by using the power adjusting value after receiving the starting instruction.
Further, the power adjustment control module is further configured to send a stop instruction to the power adjustment module if an open-loop condition is met; if receiving a monitoring office instruction, sending a stop instruction and a monitoring office instruction to the power adjustment module; the open loop condition is that the frequency difference value is kept stable when the calculation time is more than or equal to a first time; the power adjusting module is further configured to stop adjusting the output power of the power station by using the power adjusting value when the stop instruction is received; and when the stopping instruction and the monitoring bureau instruction are received, stopping adjusting the output power of the power station by using the power adjusting value, and adjusting the output power of the power station by using the monitoring bureau instruction.
Further, the power adjustment control module is further configured to send a power callback instruction when the output power of the power station is adjusted and a new monitoring office instruction is not received within a second time period greater than or equal to a second time period; the power adjusting module is further configured to receive the power callback instruction, and gradually adjust the output power of the power station to an original value.
Preferably, the sign of the adjustment coefficient is the same as the sign of the frequency difference, and the smaller the time constant of the preset short-time frequency average value is, the larger the absolute value of the adjustment coefficient is.
Preferably, the time constant of the short-time frequency mean is not greater than 1s, and the time constant of the long-time frequency mean is not less than 300 s.
Preferably, the time constant of the frequency difference filtering module is less than or equal to 5 s.
The embodiment of the invention also provides a power grid fast frequency modulation method, which is used for the device and comprises the following steps: calculating the instantaneous frequency, the short-time frequency mean value and the long-time frequency mean value of the power grid, and taking the difference between the long-time frequency mean value and the short-time frequency mean value as a frequency difference value; determining an adjusting coefficient according to the magnitude of the frequency difference value and the time constant of the short-time frequency average value; when the frequency difference value is larger than a fluctuation threshold, filtering the frequency difference value to obtain a frequency difference filtering value, and multiplying the frequency difference filtering value by the adjusting coefficient to obtain a power adjusting value; and adjusting the output power of the power station by using the power adjusting value.
Further, the method further comprises: if the open-loop condition is met, stopping adjusting the output power of the power station, if a monitoring bureau instruction is received, stopping adjusting the output power of the power station by using the power adjusting value, and adjusting the output power of the power station by using the monitoring bureau instruction; the open-loop condition is that the frequency difference value is kept stable when the calculation time is more than or equal to a first time.
Further, the method further comprises: and when the output power of the power station is adjusted and a new monitoring bureau instruction is not received within the second time, gradually adjusting the output power of the power station to the original value.
The beneficial effects of the invention include: the device realizes closed-loop control on the frequency change of the power grid, and can accurately solve the frequency problem in a range capable of being solved; in addition, the exit problem of the quick adjustment logic is definitely provided, and preparation is made for the next quick adjustment; thirdly, the invention has fast adjusting speed, does not limit the adjusting power and aims to return the frequency to the normal value within the capability range.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a diagram of an embodiment of a prior art frequency modulation method;
FIG. 2 is an embodiment of a fast frequency modulation apparatus for a power grid;
FIG. 3 is a flow chart of an embodiment of a method for fast frequency modulation of a power grid;
fig. 4 is a flow chart of an embodiment of a power grid fast frequency modulation method including power tuning back.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The power industry has strict requirements on indexes such as voltage, frequency and the like of a power grid, which is very important for guaranteeing the safe operation of the whole power grid. When the output power is changed within a certain range, the frequency and the voltage of the traditional main power plant can be kept unchanged through self adjustment. With the development of the photovoltaic and wind power industry, the proportion of the emerging green energy sources in the power grid is greater and greater, and the traditional main power plant has little worry about the adjustment of the frequency.
The frequency of the mechanical generator depends on the rotation speed of the rotor, considering a simple monopole single-phase generator, the rotor rotates one circle to cut magnetic lines of force N once and S once, so that the number of rotations per second is the frequency of the generated electricity, and if the required frequency is 50Hz, the rotation speed per minute is 3000. When the load of the generator is suddenly increased, the electromagnetic resistance applied to the rotor of the generator is suddenly increased, which inevitably slows down the rotation speed. The mechanical inertia of the generator rotor can ensure that the frequency does not change suddenly, which is very important for stabilizing the frequency, and then work needs to be added for solving the problem substantially. The sudden load reduction also causes the frequency instability problem, which is not described in detail. The current grid connection condition of green energy is that, taking a photovoltaic power station as an example, the generated electricity is firstly adjusted to high-voltage direct current, then sine wave current is fed into a power grid according to the phase difference of the power grid by 180 degrees, the product of the current and the voltage is the power output to the power grid, and a power monitoring department can send some instructions to the photovoltaic power station according to the requirements of the power grid, wherein the instructions comprise power control, power factor control and the like. Observing the grid-connected mode, the photovoltaic power station cannot compensate the frequency change quickly because the essence of compensation is to adjust the power output, the power output adjustment of the photovoltaic power station needs to wait for an instruction, and after the instruction is issued for several minutes, the quick frequency change can occur within tens of seconds. Under the condition that no new energy is added into a power grid, when the load is changed by 30% (assumed here), the frequency of the generator may only be changed by 0.1Hz under the conditions of inertial frequency stabilization and self quick adjustment, and the generator can be adjusted back within 30 seconds, but with the increase of the proportion of a green power source in the power grid, the mechanical inertia of the traditional generator cannot play a good frequency stabilization role, and meanwhile, the self generated power adjustment cannot recover the frequency within a short time, so that an instruction needs to be issued to each grid-connected green energy power plant, and the time consumption is usually several minutes to 10 minutes.
The innovation points of the invention are as follows: firstly, the existing power regulation mode adopts open-loop control regulation, the invention responds to the change of the power grid frequency in time in a closed-loop control mode, and regulates the output power of a power station according to the magnitude and the speed of the frequency change, and the closed-loop control mode has the advantages of stability and timeliness; secondly, in order to prevent unstable factors caused by frequency difference mutation in the control loop, the invention changes the adjustment coefficient of the loop in real time according to the magnitude (including a symbol) of the frequency difference and the speed and the dynamics of the frequency difference, and the adjustment effect is better and more accurate; thirdly, the power regulation control module of the invention introduces an exit mechanism, namely the loop is in a power stable state for a long time, and power is adjusted back, so that preparation can be made for next rapid control, manual operation is reduced, and the practicability is stronger.
The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.
Fig. 1 is an embodiment of a conventional frequency modulation method, which is a conventional fast frequency modulation technique and illustrates the drawbacks of the conventional technique.
In order to solve the problem of quick response of the power grid frequency, a new energy power station requiring grid connection has a quick frequency modulation technology, and the core of the technology comprises: firstly, when the power station is connected to the grid for power generation, 10% of power needs to be reserved, for example, the power station has the capability of generating 1000W of power, but only can output 900W of power, which causes the energy utilization rate to be low; secondly, the power station can accurately detect the power grid frequency, when the frequency is higher or lower than 0.1Hz, the power station automatically adjusts the output power, the adjustment mode is as shown in figure 1, the abscissa is frequency and unit Hz, the ordinate is power, the unit MW, and Pn represents the maximum output power of the power station.
In the embodiment of the invention, the green energy plant (new energy plant) must reserve a certain amount of electricity generation, for example, 10% Pn, i.e., 10% of the maximum output power of the plant.
In the embodiment of the invention, the alternating current frequency is 50Hz, and when the frequency variation range is within plus or minus 0.1Hz, the output power of the new energy power station is kept unchanged, namely the frequency is between 49.9Hz and 50.1Hz, and the new energy power station cannot participate in the rapid frequency adjustment. Therefore, when a new energy power station in a power grid is dominant and the frequency deviation is within +/-0.1 Hz, the power can be adjusted only by waiting for the instruction of a power grid monitoring office, the power station cannot be adjusted in a self-adaptive manner, and the instability phenomenon of the power grid frequency is more and more serious.
In the embodiment of the invention, when the frequency deviation is between 0.1Hz and 0.2Hz or between-0.2 Hz and-0.1 Hz, the output power of the new energy power station and the frequency change linearly, and the linear change cannot explain that the adjustment of the output power adapts to the change of the frequency, because the linear change also has a nonlinear relation, whether the adjustment of the output power of the new energy power station is correct when the frequency is between 49.8Hz and 49.9Hz or between 50.1Hz and 50.2Hz cannot be explained.
Fig. 2 is an embodiment of a fast frequency modulation apparatus for a power grid, which can be used in a new energy power station to solve the problem of fast frequency fluctuation, and specifically, the fast frequency modulation apparatus for a power grid includes: the power grid frequency control system comprises a power grid frequency calculation module 11, a frequency averaging module 12, a frequency difference calculation module 13, a frequency difference filtering module 14, a frequency difference adjusting module 15, a power adjusting control module 17 and a power adjusting module 16.
The power grid frequency calculation module is used for calculating the instantaneous frequency of a power grid; the frequency averaging module is used for receiving the instantaneous frequency of the power grid and calculating a short-time frequency average value and a long-time frequency average value; the frequency difference calculating module is used for receiving the long-time frequency mean value and the short-time frequency mean value and subtracting the long-time frequency mean value and the short-time frequency mean value to obtain a frequency difference value; the frequency difference filtering module is used for receiving the frequency difference value, outputting a frequency difference filtering value, receiving a reset signal sent by the power adjustment control module and resetting the time constant; the frequency difference adjusting module is used for receiving the frequency difference value, determining an adjusting coefficient according to the size of the frequency difference value and the preset time of the short-time frequency mean value, receiving the frequency difference filtering value, and multiplying the frequency difference filtering value by the adjusting coefficient to obtain a power adjusting value; the power adjustment control module is used for receiving the frequency difference value, and when the frequency difference value is larger than a fluctuation threshold, firstly sending a reset signal to the frequency difference filtering module and then sending a starting instruction to the power adjustment module; and the power adjusting module is used for receiving the power adjusting value, and adjusting the output power of the power station by using the power adjusting value after receiving the starting instruction.
In the embodiment of the invention, the power grid frequency calculation module has high precision and short time delay, and aims to quickly acquire the instantaneous frequency of the power grid.
In an embodiment of the present invention, the frequency averaging module may further include a short-time frequency averaging module, configured to calculate a short-time frequency average value; and the long-time frequency average module is used for calculating a long-time frequency average value. It should be noted that, for the short-time frequency average value, the average of the instantaneous frequency is to be realized, in order to obtain an instantaneous frequency value with a sufficiently high precision, so that the time constant is small, and generally, the time constant of the short-time frequency average value is not greater than 1 s; for the long-term frequency average, the long-term frequency average is to be achieved in order to obtain the long-term average of the power grid as a stable value of the power grid frequency, that is, a target value of the frequency adjustment, and generally, the time constant of the long-term frequency average is not less than 300 s.
In the embodiment of the present invention, the time constant of the short-time frequency average is 1s, and the time constant of the long-time frequency average is 300 s. It should be noted that the short-time frequency average value and the long-time frequency average value may also be other values, and are not limited herein.
In this embodiment of the present invention, the frequency difference output by the frequency difference calculation module is obtained by subtracting the short-time frequency average value from the long-time frequency average value, and is used as an error term of a control loop.
In the embodiment of the present invention, the frequency difference filtering module implements low-pass filtering on an error, that is, low-pass filtering on the frequency difference, and considers a requirement of fast frequency modulation, and a time constant of the frequency difference filtering module is less than or equal to 5s, and in the embodiment of the present invention, the time constant is 5 s. It should be noted that 5s is a set time constant, and other time constants satisfying fast frequency modulation may be set, and are not particularly limited herein.
In the embodiment of the present invention, the adjustment coefficient may be used as an adjustment control strength, which determines the stability of the entire control loop, and if the feedback is too strong, the loop cannot be quickly stabilized, and if the feedback is weak, the adjustment function is not performed. In a general control loop, feedback strength can be fixed to a proper value, and cannot be fixed in the invention because a plurality of new energy power stations adopting the same control measures can be arranged in a power grid, so that the adjustment values of the new energy power stations are added together to form a whole adjustment value, the whole adjustment value influences the frequency of a main power station, namely the control loop is not arranged in one place at all, feedback at each place is only a part, the frequency difference adjustment module can calculate whether the feedback strength is proper or not according to the change speed of instantaneous frequency difference, the proper feedback strength is given quickly, and the change speed can be determined by the time constant of the short-time frequency mean value and the size of the frequency difference.
Further, the sign of the adjustment coefficient is the same as the sign of the frequency difference value. Specifically, when the frequency difference is a negative number, that is, the short-time frequency average is greater than the long-time frequency average, and the adjustment coefficient is smaller than zero, so that the power adjustment value is smaller than zero, and the power output by the power station is adjusted to be small; when the frequency difference is positive, namely the short-time frequency mean value is smaller than the long-time frequency mean value, the adjusting coefficient is larger than zero, so that the power adjusting value is larger than zero, and the output power of the power station is increased; and when the frequency difference is 0, namely the short-time frequency mean value is equal to the long-time frequency mean value, the adjusting coefficient is zero, so that the power adjusting value is zero, and the output power of the power station is not adjusted.
Further, the smaller the time of the preset short-time frequency average value is, the larger the absolute value of the adjustment coefficient is, that is, the time constant of the short-time frequency average value is a preset value, and the smaller the value is, the faster the frequency change speed is, so that the output power can respond to the rapid adjustment, the larger the absolute value of the adjustment coefficient is, and the larger the power adjustment value is.
It should be noted that, the magnitude of the adjustment coefficient determines the magnitude of the power adjustment value, that is, the magnitude of the power adjusted by the control loop each time, for example, if the adjustment coefficient is 10, the power adjustment value is 1MW when the frequency difference is 0.1Hz in the first 1s, and the power adjustment value is 1MW when the frequency difference is still 0.1Hz in the second 1 s.
In the embodiment of the present invention, when the frequency difference is greater than the fluctuation threshold, power adjustment is required, a reset signal is sent to the frequency difference filtering module first, and then a start instruction is sent to the power adjustment module, that is, the frequency difference filtering module is restarted, and the frequency difference filtering value is recalculated for next power adjustment.
In this embodiment of the present invention, the power adjustment control module is further configured to send a stop instruction to the power adjustment module if an open-loop condition is satisfied; if receiving a monitoring office instruction, sending a stop instruction and a monitoring office instruction to the power adjustment module; the open loop condition is that the frequency difference value is kept stable when the calculation time is more than or equal to a first time; the power adjusting module is further configured to stop adjusting the output power of the power station by using the power adjusting value when the stop instruction is received; and when the stopping instruction and the monitoring bureau instruction are received, stopping adjusting the output power of the power station by using the power adjusting value, and adjusting the output power of the power station by using the monitoring bureau instruction.
Further, the power adjustment control module is further configured to send a power callback instruction when the output power of the power station is adjusted and a new monitoring office instruction is not received within a second time period greater than or equal to a second time period; the power adjusting module is further configured to receive the power callback instruction, and gradually adjust the output power of the power station to an original value.
Specifically, the power adjustment control module controls whether the power needs to be adjusted or not and how to adjust the power. Aiming at the requirement of fast power adjustment, the logic observes the output frequency difference value of the frequency difference calculation module in real time according to a preset fluctuation threshold, and when the value is larger than the fluctuation threshold, the logic firstly resets the frequency difference filtering module once and then starts the power adjustment module to realize power adjustment. The fast power adjustment logic enters a second phase when at least one of the following conditions is met: 1) when the frequency difference value of the frequency difference calculation module meets a preset threshold for a long time, a control loop is disconnected, namely the frequency difference value is kept stable when the calculation time of the frequency difference value is more than or equal to the first time, and the power adjustment module is forbidden to be started; 2) and when the new energy power station receives a clear adjustment instruction of a monitoring bureau, the control loop is disconnected, the new energy power station adjusts according to the instruction, namely the new energy power station receives the instruction of the monitoring bureau, a stop instruction and the instruction of the monitoring bureau are sent to the power adjustment module, and the power adjustment module directly adjusts the output power according to the instruction of the monitoring bureau. If the control logic is in the second stage and the monitoring office instruction is not received within a period of time (greater than or equal to the second time), the output power is adjusted in steps in the opposite direction until the original set value (original value) is reached, i.e. the output power is adjusted back to the original value, which is ready for the next fast adjustment.
It should be noted that, the output power of the power station is gradually adjusted to the original value, the power can be gradually adjusted according to the adjusted output power and the original value, and if the adjustment is smaller than the original value, the output power of the power station can be adjusted to the original value at one time or adjusted to the original value step by step for many times; if the output power is adjusted to be larger than the original value, the output power of the power station can be adjusted to the original value step by step for many times.
It should be noted that, in the present invention, the fluctuation threshold, the first time, and the second time are all set values, and are not particularly limited.
The power grid rapid frequency modulation device provided by the embodiment of the invention adopts a closed-loop control mode, has smaller dead zone, can be set, has high response speed, can accurately solve the problem of rapid frequency change, and determines the exit problem of rapid adjustment logic, so that preparation is made for next rapid adjustment, and the device has simple design and strong practicability.
Fig. 3 is a flow embodiment of a power grid fast frequency modulation method, which may be used in the power grid fast frequency modulation device of the present invention, and as an embodiment of the present invention, the power grid fast frequency modulation method includes the following steps:
step 101, calculating the instantaneous frequency, the short-time frequency mean value and the long-time frequency mean value of the power grid, and taking the difference between the long-time frequency mean value and the short-time frequency mean value as a frequency difference value.
In step 101, the method for calculating the grid instantaneous frequency, the short-time frequency mean value, the long-time frequency mean value and the frequency difference value is described in detail in the second embodiment, and will not be repeated here.
And 102, determining an adjusting coefficient according to the magnitude of the frequency difference value and the time of the short-time frequency average value.
In step 102, the method of determining the adjustment coefficient has been discussed in detail in the second embodiment, and the discussion is not repeated here.
And 103, when the frequency difference value is larger than the fluctuation threshold, filtering the frequency difference value to obtain a frequency difference filtering value, and multiplying the frequency difference filtering value by the adjusting coefficient to obtain a power adjusting value.
In step 103, the method for obtaining the power adjustment value is described in detail in the second embodiment, and the discussion is not repeated here.
And 104, adjusting the output power of the power station by using the power adjusting value.
In step 104, the output power of the plant is adjusted to add the power adjustment value on the basis of the existing output power.
The embodiment of the invention provides a power grid rapid frequency modulation method, which adopts a closed-loop control mode, adjusts the output power of a power station according to the size and speed of the instantaneous frequency change of a power grid, and can correct an adjustment coefficient in real time according to a frequency difference value by a self-adaptive adjustment mode, thereby realizing nonlinear adjustment, high accuracy and strong practicability.
Fig. 4 is a flow embodiment of a power grid fast frequency modulation method including power callback, in which an exit mechanism and power callback are added, and as an embodiment of the present invention, a power grid fast frequency modulation method includes the following steps:
step 101, calculating the instantaneous frequency, the short-time frequency mean value and the long-time frequency mean value of the power grid, and taking the difference between the long-time frequency mean value and the short-time frequency mean value as a frequency difference value.
And 102, determining an adjusting coefficient according to the magnitude of the frequency difference value and the time of the short-time frequency average value.
And 103, when the frequency difference value is larger than the fluctuation threshold, filtering the frequency difference value to obtain a frequency difference filtering value, and multiplying the frequency difference filtering value by the adjusting coefficient to obtain a power adjusting value.
And 105, stopping adjusting the output power of the power station if the open-loop condition is met, stopping adjusting the output power of the power station by using the power adjusting value if a monitoring office instruction is received, and adjusting the output power of the power station by using the monitoring office instruction.
In step 105, the open loop condition is that the frequency difference value is stable when the calculation time is equal to or longer than the first time.
It should be noted that, the keeping of the frequency difference value is to fix the frequency value near a certain value, for example, fix the frequency value at a certain value plus or minus 0.01Hz, where 0.01Hz is a preset value, and is not limited specifically.
In step 105, when the frequency difference is stable for a long time, the output power of the power station does not need to be adjusted, and the power grid is in a relatively stable power supply environment.
In step 105, when the monitoring station command is received, the priority of the monitoring station command is highest, and the output power of the power station is adjusted according to the data in the command.
And step 106, gradually adjusting the output power of the power station to the original value when the output power of the power station is adjusted and no new monitoring bureau instruction is received within the second time.
In step 106, when the output power of the power station is in the adjusted value for a long time, no instruction from the monitoring bureau is received at this time, and considering that the power station (such as a wind power station and a water power station) which is dominant in the power grid has already finished the power adjustment, the new energy power station modulates the output power by a preset original value to prepare for the next frequency rapid change.
The power grid rapid frequency modulation method provided by the embodiment of the invention has the functions of loop disconnection and power callback, comprehensively considers the output power change condition of each power station in the power grid, has higher power adjustment accuracy and enables the whole power grid to run more stably.
It is to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The above description is only an example of the present invention, and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (9)
1. A fast frequency modulation device for a power grid is characterized by comprising:
the power grid frequency calculation module is used for calculating the instantaneous frequency of a power grid;
the frequency averaging module is used for receiving the instantaneous frequency of the power grid and calculating a short-time frequency average value and a long-time frequency average value;
the frequency difference calculation module is used for receiving the long-time frequency mean value and the short-time frequency mean value and subtracting the long-time frequency mean value and the short-time frequency mean value to obtain a frequency difference value;
the frequency difference filtering module is used for receiving the frequency difference value, outputting a frequency difference filtering value, receiving a reset signal sent by the power adjustment control module and resetting the time constant;
the frequency difference adjusting module is used for receiving the frequency difference value, determining an adjusting coefficient according to the size of the frequency difference value and a preset time constant of the short-time frequency average value, receiving the frequency difference filtering value and multiplying the frequency difference filtering value by the adjusting coefficient to obtain a power adjusting value;
the power adjustment control module is used for receiving the frequency difference value, and when the frequency difference value is larger than a fluctuation threshold, firstly sending a reset signal to the frequency difference filtering module and then sending a starting instruction to the power adjustment module;
and the power adjusting module is used for receiving the power adjusting value, and adjusting the output power of the power station by using the power adjusting value after receiving the starting instruction.
2. A grid chirp mechanism as claimed in claim 1,
the power adjustment control module is further configured to,
if the open-loop condition is met, sending a stop instruction to the power adjusting module;
if receiving a monitoring office instruction, sending a stop instruction and a monitoring office instruction to the power adjustment module;
the open loop condition is that the frequency difference value is kept stable when the calculation time is more than or equal to a first time;
the power adjustment module is further configured to,
when the stop instruction is received, stopping adjusting the output power of the power station by using the power adjusting value;
and when the stopping instruction and the monitoring bureau instruction are received, stopping adjusting the output power of the power station by using the power adjusting value, and adjusting the output power of the power station by using the monitoring bureau instruction.
3. A grid chirp mechanism as claimed in claim 1,
the power adjustment control module is further used for sending a power callback instruction when the output power of the power station is adjusted and a new monitoring bureau instruction is not received within a second time which is more than or equal to a second time;
the power adjusting module is further configured to receive the power callback instruction, and gradually adjust the output power of the power station to an original value.
4. A device for fast frequency modulation according to claim 1, wherein the sign of the adjustment coefficient is the same as the sign of the frequency difference, and the smaller the time constant of the preset short-time frequency average value is, the larger the absolute value of the adjustment coefficient is.
5. A system for fast frequency modulation according to claim 1, wherein the time constant of the short-time frequency average is not greater than 1s, and the time constant of the long-time frequency average is not less than 300 s.
6. A system for fast frequency modulation according to claim 1, wherein the time constant of the frequency difference filtering module is less than or equal to 5 s.
7. A method for fast frequency modulation of a power grid, which is used for the device of any one of claims 1 to 6, and is characterized by comprising the following steps:
calculating the instantaneous frequency, the short-time frequency mean value and the long-time frequency mean value of the power grid, and taking the difference between the long-time frequency mean value and the short-time frequency mean value as a frequency difference value;
determining an adjusting coefficient according to the magnitude of the frequency difference value and the time constant of the short-time frequency average value;
when the frequency difference value is larger than a fluctuation threshold, filtering the frequency difference value to obtain a frequency difference filtering value, and multiplying the frequency difference filtering value by the adjusting coefficient to obtain a power adjusting value;
and adjusting the output power of the power station by using the power adjusting value.
8. A method for grid frequency fast modulation as claimed in claim 7, further comprising:
if the open-loop condition is met, stopping adjusting the output power of the power station, if a monitoring bureau instruction is received, stopping adjusting the output power of the power station by using the power adjusting value, and adjusting the output power of the power station by using the monitoring bureau instruction;
the open-loop condition is that the frequency difference value is kept stable when the calculation time is more than or equal to a first time.
9. A method for grid frequency fast modulation as claimed in claim 8, further comprising:
and when the output power of the power station is adjusted and a new monitoring bureau instruction is not received within the second time, gradually adjusting the output power of the power station to the original value.
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Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101488664A (en) * | 2009-02-27 | 2009-07-22 | 上海航锐电源科技有限公司 | Anti-island effect protection method based on output current frequency disturbance |
| CN102629762A (en) * | 2012-04-24 | 2012-08-08 | 湖北省电力公司电力试验研究院 | Floating frequency difference regulation and variable rate load instruction modification-based primary frequency regulation method |
| CN104300583A (en) * | 2014-11-03 | 2015-01-21 | 南方电网科学研究院有限责任公司 | Microgrid frequency control method based on adjusting response characteristic of devices |
| CN104917201A (en) * | 2015-06-16 | 2015-09-16 | 山东大学 | Controller and method for simulating active power frequency of double-fed induction generator (DFIG) in combination with inertia and over speed |
| CN105391078A (en) * | 2015-11-03 | 2016-03-09 | 中国大唐集团科学技术研究院有限公司华中分公司 | Primary frequency regulation closed loop control method for generator set |
| CN107453375A (en) * | 2017-07-06 | 2017-12-08 | 中国长江电力股份有限公司 | Primary frequency modulation electricity compensation Precise control method and device under giant water turbine generator set power mode |
| CN108695897A (en) * | 2018-06-27 | 2018-10-23 | 北京金风科创风电设备有限公司 | Power control method, device, controller, system and medium for photovoltaic power station |
| CN109888796A (en) * | 2019-03-06 | 2019-06-14 | 中国电力科学研究院有限公司 | A kind of battery energy storage power station control method and system for primary frequency regulation of power network |
| CN110266052A (en) * | 2019-07-22 | 2019-09-20 | 武汉能众科技有限公司 | A kind of fast frequency hopping device and method suitable for photovoltaic plant |
| CN111030142A (en) * | 2020-01-02 | 2020-04-17 | 重庆大学 | Multi-time scale frequency optimization control method for high-proportion wind power system |
| US20200169219A1 (en) * | 2017-12-31 | 2020-05-28 | Beijing Goldwind Science & Creation Windpower Equipment Co., Ltd. | Photovoltaic power plant and primary frequency modulation control method therefor |
-
2020
- 2020-06-16 CN CN202010547634.4A patent/CN111900741B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101488664A (en) * | 2009-02-27 | 2009-07-22 | 上海航锐电源科技有限公司 | Anti-island effect protection method based on output current frequency disturbance |
| CN102629762A (en) * | 2012-04-24 | 2012-08-08 | 湖北省电力公司电力试验研究院 | Floating frequency difference regulation and variable rate load instruction modification-based primary frequency regulation method |
| CN104300583A (en) * | 2014-11-03 | 2015-01-21 | 南方电网科学研究院有限责任公司 | Microgrid frequency control method based on adjusting response characteristic of devices |
| CN104917201A (en) * | 2015-06-16 | 2015-09-16 | 山东大学 | Controller and method for simulating active power frequency of double-fed induction generator (DFIG) in combination with inertia and over speed |
| CN105391078A (en) * | 2015-11-03 | 2016-03-09 | 中国大唐集团科学技术研究院有限公司华中分公司 | Primary frequency regulation closed loop control method for generator set |
| CN107453375A (en) * | 2017-07-06 | 2017-12-08 | 中国长江电力股份有限公司 | Primary frequency modulation electricity compensation Precise control method and device under giant water turbine generator set power mode |
| US20200169219A1 (en) * | 2017-12-31 | 2020-05-28 | Beijing Goldwind Science & Creation Windpower Equipment Co., Ltd. | Photovoltaic power plant and primary frequency modulation control method therefor |
| CN108695897A (en) * | 2018-06-27 | 2018-10-23 | 北京金风科创风电设备有限公司 | Power control method, device, controller, system and medium for photovoltaic power station |
| CN109888796A (en) * | 2019-03-06 | 2019-06-14 | 中国电力科学研究院有限公司 | A kind of battery energy storage power station control method and system for primary frequency regulation of power network |
| CN110266052A (en) * | 2019-07-22 | 2019-09-20 | 武汉能众科技有限公司 | A kind of fast frequency hopping device and method suitable for photovoltaic plant |
| CN111030142A (en) * | 2020-01-02 | 2020-04-17 | 重庆大学 | Multi-time scale frequency optimization control method for high-proportion wind power system |
Non-Patent Citations (1)
| Title |
|---|
| 王永潭;孔凡场;杨建全;: "小山电站水轮发电机组一次调频功能的实现", 吉林电力, no. 01, pages 40 - 41 * |
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|---|---|
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