Power grid secondary frequency modulation control method and device taking non-rated frequency as regulation target

Abstract

The invention discloses a power grid secondary frequency modulation control method and device with an unrated frequency as an adjustment target, and the method comprises the steps: improving the primary frequency modulation capability of a power grid, determining a dead zone of the secondary frequency modulation of the power grid based on the frequency fluctuation range of the power grid and the power disturbance quantity facing the power grid, and effectively avoiding frequent and unnecessary frequency modulation actions. Therefore, the stability and economical efficiency of power grid operation are improved. And secondary frequency modulation is performed on the power grid by taking the power grid frequency entering the dead zone range and considering that the frequency reflects the peak regulation demand of the power grid as the regulation target, so that the frequency modulation and peak regulation capability of the power grid is enhanced, and the frequency modulation and peak regulation efficiency of the grid-connected new energy power supply is optimized. The increase of the secondary frequency modulation dead zone greatly reduces the secondary frequency modulation process of the power grid, and avoids the phenomena of waste of adjustment resources and increase of the frequency modulation cost of the power grid caused by frequent adjustment of secondary frequency modulation.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system operation control, and relates to a power grid secondary frequency regulation control method and device with a non-rated frequency as a regulation target. Background Art

[0002] Grid frequency regulation and peak load regulation are important aspects of power system operation and control. Especially in power grids with a high proportion of new energy, the grid maintains a balanced relationship between grid-connected power generation output and load through frequency regulation and peak load regulation operation control, not only to maintain the grid frequency stable at the rated frequency f e It is also an important technical field for promoting the construction of a new clean and low-carbon power system in my country.

[0003] In traditional grid frequency control theory, grid frequency stability control is mainly completed by primary frequency control (PFC) actively supported by grid-connected power sources and secondary frequency control dominated by grid control at all levels. Primary frequency control is mainly responsible for balancing short-term, smaller power fluctuations, but due to its differential regulation characteristics, it alone cannot stabilize the grid frequency to the rated frequency, or more precisely, it cannot stabilize the grid frequency to within the frequency dead zone of its primary frequency control. Therefore, secondary frequency control that can be adjusted without differential regulation is needed to adjust the grid frequency to the rated frequency or the frequency dead zone of PFC.

[0004] At present, the secondary frequency regulation of the power grid is based on the rated frequency of the power grid as the frequency regulation target. Under normal circumstances, when the deviation of the power grid frequency relative to the rated frequency reaches the action threshold, or when the real-time size of the area control error (ACE) and its cumulative deviation over time reach the corresponding threshold, the first frequency regulation plant of the power grid or other units responsible for the stability of the power grid frequency will start the secondary frequency regulation process to ensure that the power grid frequency is as stable as possible at the rated frequency and maintain the stability of the interconnection line power. Although it is not necessarily possible to stabilize the power grid frequency to the rated frequency due to the influence of power grid power fluctuations and the control accuracy and regulation performance of the secondary frequency regulation, in most cases, the power grid frequency will shuttle back and forth and fluctuate in a very small frequency range near the rated frequency (for example, within 50.00±0.03Hz), but for the power grid frequency control, the rated frequency is the regulation target.

[0005] At present, the frequency regulation and peak regulation of power grids not only have to deal with the randomness, volatility and intermittency of power load, but also the randomness, volatility and intermittency caused by the high proportion of photovoltaic power generation and wind power. At the same time, large-scale transmission failures of ultra-high voltage AC and DC across regions, large-scale disconnection of new energy sources caused by accidents within the power grid and large load disturbances all seriously threaten the stability of power grid frequency. It is urgently needed for the power grid to have stronger and better frequency regulation, peak regulation and the ability to maintain power balance of the power grid. In particular, when faced with the dual dilemma of power supply and new energy consumption, there is an urgent need for power regulation capabilities on a time scale of more than 15 minutes and larger.

[0006] At present, the industry advocates the configuration of pumped storage units, electrochemical and new energy storage, and the improvement of the frequency and peak regulation capabilities of water and thermal power units to improve the frequency and peak regulation capabilities of the power grid. Compared with various power grid frequency regulation and peak regulation resources, the primary frequency regulation of photovoltaic power generation and wind power is more advantageous than the primary frequency regulation or secondary frequency regulation process of water and thermal power units in terms of regulation performance and operating costs. The existing methods can quickly and efficiently enhance the primary frequency regulation capabilities of power grids with a high proportion of new energy, and achieve an exponential increase in the primary frequency regulation capabilities of the power grid. However, according to the current secondary frequency regulation control strategy and method of the power grid with rated frequency as the regulation target, the primary frequency regulation capability of the power grid can only play a role on a time scale of seconds in most cases, and its role is difficult to last for more than 1 minute. Therefore, there is an urgent need for a method to meet the secondary frequency regulation control of the power grid, so as to make full use of the economical and efficient primary frequency regulation of new energy and the high-performance power grid frequency and peak regulation resources. Summary of the invention

[0007] The purpose of the present invention is to solve the problem that in the prior art, the primary frequency regulation capability of the power grid can only function on a time scale of seconds in most cases, and to provide a method and device for secondary frequency regulation of the power grid with non-rated frequency as the regulation target.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a power grid secondary frequency regulation control method with non-rated frequency as the regulation target, comprising: Improve the primary frequency regulation capability of the power grid, and determine the dead zone of the secondary frequency regulation of the power grid based on the frequency fluctuation range of the power grid and the power disturbance faced by the power grid; The grid is subjected to secondary frequency modulation with the goal of the grid frequency entering the dead zone range, thereby realizing secondary frequency modulation operation control of the grid.

[0009] Optionally, in the process of performing secondary frequency regulation on the power grid with the goal of the power grid frequency entering the dead zone range, the frequency accurately reflects the peak-shaving demand of the power grid as the regulation goal.

[0010] Optionally, in the process of performing secondary frequency modulation on the power grid with the power grid frequency entering the dead zone range as the goal, when the power grid frequency operates at (50.000-E ’ )Hz~(50.000+E)Hz, if the current and expected subsequent power generation output of the power grid is higher than the load power, the power grid frequency is maintained at a higher frequency value of (50.000-E')Hz~(50.000+E)Hz; conversely, the current and expected subsequent power load power is higher than the power generation output, the power grid frequency is maintained at a lower frequency value of (50.000-E')Hz~(50.000+E)Hz, where E is the upper limit threshold value of the secondary frequency regulation frequency dead zone when the frequency increases; E' is the lower limit threshold value of the secondary frequency regulation frequency dead zone when the frequency decreases.

[0011] Optionally, the principle for determining the dead zone of the secondary frequency regulation of the power grid is as follows: in daily operation of the power grid, the power grid frequency is stabilized at around the rated frequency of (50.000-E') Hz to (50.000+E) Hz by relying solely on the primary frequency regulation of the power grid; when the power grid frequency is stably running at (50.000-E') Hz to (50.000+E) Hz, for large power disturbance events that may occur in the power grid, the frequency safety of the power grid is still ensured by relying on the subsequent primary and secondary frequency regulation capabilities of the power grid and relevant stability measures of the power grid; E and E' are dynamically adjusted in a timely manner according to the actual operation mode of the power grid and other situations that affect frequency safety; wherein E is the upper limit threshold value of the secondary frequency regulation dead zone when the frequency increases; and E' is the lower limit threshold value of the secondary frequency regulation dead zone when the frequency decreases.

[0012] Optionally, the improving the primary frequency regulation capability of the power grid is specifically: Obtaining a primary frequency modulation dead zone of a non-renewable energy grid-connected power source in the power grid; setting a primary frequency modulation dead zone of a new energy grid-connected power source in the power grid based on the primary frequency modulation dead zone of the non-renewable energy grid-connected power source; wherein the absolute value of the primary frequency modulation dead zone of a first preset proportion of new energy grid-connected power sources in the power grid is smaller than the absolute value of the primary frequency modulation dead zone of all or a second preset proportion of non-renewable energy grid-connected power sources in the power grid; Obtain the installed capacity and daily power operation range of the new energy grid-connected power supply with primary frequency regulation capability in the power grid, and the unbalanced power situation of the power grid for 1 to 15 minutes on a daily basis; based on the installed capacity and daily power operation range of the new energy grid-connected power supply with primary frequency regulation capability, and the unbalanced power situation of the power grid for 1 to 15 minutes on a daily basis, set the primary frequency regulation difference rate of the new energy grid-connected power supply in the power grid in combination with the primary frequency regulation frequency dead zone of the new energy grid-connected power supply in the power grid; Based on the primary frequency modulation dead zone and primary frequency modulation difference rate of the renewable energy grid-connected power supply, the primary frequency modulation of the renewable energy grid-connected power supply is realized; based on the primary frequency modulation dead zone and primary frequency modulation difference rate of the non-renewable energy grid-connected power supply, the primary frequency modulation of the non-renewable energy grid-connected power supply is realized; based on the primary frequency modulation of the renewable energy grid-connected power supply and the primary frequency modulation of the non-renewable energy grid-connected power supply, the frequency modulation operation control of the power grid is realized.

[0013] Optionally, the specific adjustment process of the secondary frequency regulation with the grid frequency entering the secondary frequency regulation dead zone range as the adjustment target is: when the grid frequency exceeds the set grid dead zone frequency range, the regional control deviation ACE calculation method based on the secondary frequency regulation is adjusted, and the secondary frequency regulation is performed accordingly to achieve the adjustment of the grid frequency to within the grid secondary frequency regulation dead zone frequency range.

[0014] Optionally, the regional control deviation ACE based on the secondary frequency modulation is regulated, specifically: When the grid frequency exceeds the range of (50.000-E') Hz to (50.000+E) Hz, the secondary frequency regulation starts to adjust the grid frequency to between (50.000-E') Hz and (50.000+E) Hz; and the calculation method of the regional control deviation ACE based on the secondary frequency regulation is changed, and the regional control deviation ACE is: ACE=k△f+△P Wherein, k is the frequency modulation coefficient or the regional frequency deviation coefficient, △f is the frequency deviation, and △P is the deviation between the preset value and the actual value of the active power of the tie line;

[0015] in, is the rated frequency.

[0016] The present invention also provides a power grid secondary frequency regulation control system with non-rated frequency as the regulation target, comprising: A determination module, wherein the determination module improves the primary frequency regulation capability of the power grid and determines a dead zone of the secondary frequency regulation of the power grid based on the frequency fluctuation range of the power grid and the power disturbance amount faced by the power grid; A frequency modulation module, wherein the frequency modulation module performs secondary frequency modulation on the power grid when the power grid frequency enters the dead zone range, thereby realizing secondary frequency modulation operation control of the power grid.

[0017] A terminal device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0018] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention improves the primary frequency regulation capability of the power grid, and determines the dead zone of the secondary frequency regulation of the power grid based on the frequency fluctuation range of the power grid and the power disturbance faced by the power grid, which can effectively avoid frequent and unnecessary frequency regulation actions, thereby improving the stability and economy of the power grid operation. The power grid is subjected to secondary frequency regulation with the power grid frequency entering the dead zone range and taking into account the frequency reflecting the peak regulation demand of the power grid as the regulation target, which enhances the frequency regulation and peak regulation capability of the power grid, optimizes the frequency regulation and peak regulation efficiency of the grid-connected new energy power source, and solves the problem that the primary frequency regulation cannot continue to play a role on a larger time scale due to the frequent regulation of the secondary frequency regulation of the power grid. At the same time, the primary frequency regulation of new energy is fully utilized to provide peak regulation for the power grid on a larger time scale such as 15 minutes and hours. The increase in the secondary frequency regulation dead zone greatly reduces the secondary frequency regulation process of the power grid, avoiding the waste of regulation resources and the increase of the frequency regulation cost of the power grid caused by the frequent regulation of the secondary frequency regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a flow chart of a method for controlling secondary frequency regulation of a power grid with non-rated frequency as a regulation target according to the present invention; Figure 2 It is a structural schematic diagram of a power grid secondary frequency regulation control system with non-rated frequency as the regulation target according to the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0025] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0026] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0027] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The present invention is further described in detail below in conjunction with the accompanying drawings: See also Figure 1 The present invention discloses a secondary frequency regulation control method for a power grid with a non-rated frequency as a regulation target, comprising: S101: Improve the primary frequency regulation capability of the power grid, and determine the dead zone of the secondary frequency regulation of the power grid based on the frequency fluctuation range of the power grid and the power disturbance faced by the power grid, specifically: The method for improving the primary frequency regulation capability of a power grid is as follows: obtaining the primary frequency regulation dead zone of a non-new energy grid-connected power source in the power grid; and setting the primary frequency regulation dead zone of a new energy grid-connected power source in the power grid based on the primary frequency regulation dead zone of the non-new energy grid-connected power source; wherein the absolute value of the primary frequency regulation dead zone of a first preset proportion of new energy grid-connected power sources in the power grid is less than the absolute value of the primary frequency regulation dead zone of all or a second preset proportion of non-new energy grid-connected power sources in the power grid; Obtain the installed capacity and daily power operation range of the new energy grid-connected power supply with primary frequency regulation capability in the power grid, and the unbalanced power situation of the power grid for 1 to 15 minutes on a daily basis; based on the installed capacity and daily power operation range of the new energy grid-connected power supply with primary frequency regulation capability, and the unbalanced power situation of the power grid for 1 to 15 minutes on a daily basis, set the primary frequency regulation difference rate of the new energy grid-connected power supply in the power grid in combination with the primary frequency regulation frequency dead zone of the new energy grid-connected power supply in the power grid; Based on the primary frequency modulation dead zone and primary frequency modulation difference rate of the new energy grid-connected power supply, the primary frequency modulation of the new energy grid-connected power supply is realized; based on the primary frequency modulation dead zone and primary frequency modulation difference rate of the non-new energy grid-connected power supply, the primary frequency modulation of the non-new energy grid-connected power supply is realized; based on the primary frequency modulation of the new energy grid-connected power supply and the primary frequency modulation of the non-new energy grid-connected power supply, the frequency modulation operation control of the power grid is realized. Further measures include requiring all grid-connected power sources including distributed power sources and virtual power plants to have primary frequency modulation functions and meet the corresponding technical requirements. The substantial improvement of the primary frequency modulation capacity of the power grid can stabilize the power grid frequency near the rated frequency (for example, within 49.95 to 50.05 Hz) by primary frequency modulation alone under daily load and new energy fluctuations. Based on this frequency range and the subsequent primary frequency modulation capacity and the amount of power disturbance that the power grid will face, the secondary frequency modulation frequency dead zone of the power grid is determined to be (50.000-E ’ )Hz~(50.000+E)Hz. E is the upper limit threshold of the secondary frequency modulation dead zone when the frequency increases; E ’ It is the lower limit threshold of the secondary frequency dead zone when the frequency is reduced.

[0029] When determining the dead zone of the secondary frequency regulation of the power grid, three principles need to be considered: in the daily operation of the power grid, the power grid frequency is stabilized at around the rated frequency of (50.000-E') Hz to (50.000+E) Hz by the primary frequency regulation of the power grid alone; when the power grid frequency is stably running at (50.000-E') Hz to (50.000+E) Hz, for large power disturbance events that may occur in the power grid, the subsequent primary and secondary frequency regulation capabilities of the power grid and the relevant stability measures of the power grid are still used to ensure the frequency safety of the power grid; E and E' are dynamically adjusted in a timely manner according to the actual operation mode of the power grid and other situations that affect frequency safety; among them, E is the upper limit threshold value of the secondary frequency regulation dead zone when the frequency increases; E' is the lower limit threshold value of the secondary frequency regulation dead zone when the frequency decreases.

[0030] S102: The grid is subjected to secondary frequency modulation with the grid frequency entering the dead zone as the target, so as to realize secondary frequency modulation operation control of the grid. Preferably, when the grid is subjected to secondary frequency modulation with the grid frequency entering the dead zone as the target, the frequency is taken into account to accurately reflect the peak load demand of the grid as the regulation target, that is, the secondary frequency modulation takes the grid frequency entering the secondary frequency modulation dead zone as one of the regulation targets. The specific regulation process is as follows: When the grid frequency is running at (50.000-E ’ )Hz~(50.000+E)Hz, the secondary frequency regulation will no longer be carried out with the rated frequency as the target, unless it is for the purpose of making the grid frequency more accurately reflect the peak demand of the grid. In other words, when the grid frequency operates in this range, let the primary frequency regulation of the grid play the main frequency regulation role. When the grid-connected power output is greater than the load power (for example, when the consumption of new energy is the main problem to be solved by the grid), the grid frequency is stabilized at a frequency value larger than the rated frequency through the differential regulation of the primary frequency regulation; when the grid load is at peak time and the load is greater than the grid-connected power output (for example, when the power supply is the main problem to be solved by the grid), the grid frequency is stabilized at a frequency value smaller than the rated frequency through the differential regulation of the primary frequency regulation. The secondary frequency regulation of the grid no longer carries out the regulation process with the purpose of adjusting the grid frequency to the rated frequency, but as an auxiliary means, with the grid frequency being able to more accurately reflect the peak demand of the grid as the regulation goal. The higher the current and expected subsequent grid output is greater than the load, the grid frequency is maintained at (50.000-E ’ )Hz~(50.000+E)Hz higher frequency value; on the contrary, the higher the current and expected subsequent power grid load is than the output, the power grid frequency is maintained at (50.000-E ’ )Hz~(50.000+E)Hz lower frequency value.

[0031] When the grid frequency exceeds the set grid dead zone frequency range, the regional control deviation ACE calculation method based on the secondary frequency regulation is adjusted, and the secondary frequency regulation is performed accordingly to adjust the grid frequency to within the grid secondary frequency regulation dead zone frequency range, specifically: When the grid frequency exceeds the range of (50.000-E') Hz to (50.000+E) Hz, the secondary frequency regulation starts to adjust the grid frequency to between (50.000-E') Hz and (50.000+E) Hz; and the calculation method of the regional control deviation ACE based on the secondary frequency regulation is changed, and the regional control deviation ACE is: ACE=k△f+△P Wherein, k is the frequency modulation coefficient or the regional frequency deviation coefficient, △f is the frequency deviation, and △P is the deviation between the preset value and the actual value of the active power of the tie line;

[0032] in, is the rated frequency.

[0033] See also Figure 2 The present invention discloses a power grid secondary frequency regulation control system with non-rated frequency as the regulation target, comprising: A determination module, wherein the determination module improves the primary frequency regulation capability of the power grid and determines a dead zone of the secondary frequency regulation of the power grid based on the frequency fluctuation range of the power grid and the power disturbance amount faced by the power grid; A frequency modulation module, wherein the frequency modulation module performs secondary frequency modulation on the power grid when the power grid frequency enters the dead zone range, thereby realizing secondary frequency modulation operation control of the power grid.

[0034] Example: The present invention discloses a secondary frequency regulation control method for a power grid with a non-rated frequency as a regulation target, comprising: A. The power grid frequency regulation operation control method with priority to the primary frequency regulation of new energy in the prior art can improve the primary frequency regulation capability of the power grid, especially greatly improve the primary frequency regulation efficiency of new energy. The significant improvement of the primary frequency regulation capability of the power grid can stabilize the power grid frequency near the rated frequency (for example, within 49.95-50.05Hz) by primary frequency regulation alone under the condition of daily load and fluctuation of new energy. Based on this frequency range and the subsequent primary frequency regulation capability and the power disturbance amount that the power grid will face, the secondary frequency regulation frequency dead zone of the power grid is determined to be (50.000-E ’ )Hz~(50.000+E)Hz. E is the upper limit threshold value of the secondary frequency modulation dead zone when the frequency increases; E' is the lower limit threshold value of the secondary frequency modulation dead zone when the frequency decreases.

[0035] The determination of E and E' takes into account the following principles: 1) The grid frequency can be stabilized at around the rated frequency of (50.000-E')Hz to (50.000+E)Hz by only one frequency regulation of the grid; 2) When the grid frequency is running stably at (50.000-E')Hz~(50.000+E)Hz, the grid frequency safety can still be ensured by relying on the subsequent primary and secondary frequency regulation capabilities of the grid and related stabilization measures for large power disturbance events that may occur in the grid.

[0036] 3) E and E' can be adjusted dynamically in a timely manner according to the actual operation mode of the power grid and other situations that affect frequency security.

[0037] Let's take a certain power grid as an example to explain it in detail. At present, the primary frequency regulation parameters of each grid-connected power source thermal power (including solar thermal units), hydropower (including pumped storage units), photovoltaic, wind power, and new energy storage in a certain power grid are set as follows: the primary frequency regulation frequency dead zone is set to ±0.033Hz, ±0.05Hz, ±0.06Hz, ±0.10Hz, ±0.03Hz respectively; the primary frequency regulation difference rate is set to 4-5%, 3%, 3%, 2%, and 2% respectively. The action condition for the secondary frequency regulation to adjust the grid frequency is that the frequency deviation is greater than 0.02Hz and the cumulative deviation value of the frequency deviation over time exceeds the threshold value for secondary frequency regulation. Under the current primary and secondary frequency regulation and related stabilization measures, the grid frequency can be maintained within 50±0.05Hz for 90% of the year, and the minute-level secondary frequency regulation adjustment amount is basically within 2 million kw.

[0038] According to the above basic conditions, if the primary frequency regulation parameters of photovoltaic, wind power and new energy storage in the grid are optimized, the frequency dead zone is set to ±0.02Hz, ±0.03Hz, ±0.03Hz respectively; the difference rate is set to 2%, 2%, 0.5% respectively; the primary frequency regulation parameters of hydropower and thermal power units remain unchanged. After analysis and optimization, when the grid frequency is stabilized within 50±0.05Hz, the regulation capacity of new energy and new energy storage is increased. At present, the grid-connected photovoltaic power generation capacity of the power grid has reached more than 150 million kilowatts. During daytime photovoltaic power generation, the effective grid-connected photovoltaic power generation capacity with ±3% primary frequency regulation capability is calculated as 100 million kilowatts. When the grid frequency is stable within 50±0.05Hz, the increased regulation capacity of photovoltaic primary frequency regulation is ±3 million kilowatts; the grid-connected wind power capacity of the power grid has reached 116 million kilowatts, and the effective grid-connected capacity with ±2% primary frequency regulation capability is calculated as 70 million kilowatts (about 60% of the wind power installed capacity). When the grid frequency is stable within 50±0.05Hz, the increased regulation capacity of wind power primary frequency regulation is ±1.4 million kilowatts; a certain power grid has 18.73 million kilowatts of new energy storage installed capacity, and the primary frequency regulation difference rate is optimized from 2% to 0.5%. Through the primary frequency regulation of the new energy storage, when the grid frequency is maintained within 50±0.05Hz, the new energy storage provides a regulation capacity of ±1.12 million kilowatts. It can be inferred that the newly added primary frequency regulation capacity can completely replace the original secondary frequency regulation to maintain the grid frequency within 50±0.05Hz. In other words, after optimization, the grid can stabilize the grid frequency at around the rated frequency of (50.000-0.05)Hz to (50.000+0.05)Hz by relying solely on the primary frequency regulation.

[0039] Considering the optimization plan, when the grid frequency is maintained within 50±0.05Hz, the primary frequency regulation of hydropower (including pumped storage units) has basically not played a role; according to the limit stipulated in the national standard, the primary frequency regulation of thermal power units only plays 10% of its maximum regulation capacity, the primary frequency regulation of photovoltaic power generation only plays 50% of its maximum regulation capacity, the primary frequency regulation of wind power only plays 33% of its maximum regulation capacity, and the primary frequency regulation of new energy storage only plays 40% of its maximum regulation capacity. For the large power disturbance events that may occur in the power grid, the subsequent primary and secondary frequency regulation capabilities of the power grid and the relevant stability measures of the power grid can still ensure the frequency safety of the power grid. Moreover, with the continuous increase in the subsequent grid-connected capacity of new energy and new energy storage, the frequency regulation capacity of the power grid will be further enhanced.

[0040] In summary, after the primary frequency regulation parameters of photovoltaic, wind power and new energy storage are optimized, E and E' can be taken as 0.05 Hz or dynamically adjusted to a larger value based on the estimation of the primary frequency regulation capability of the power grid.

[0041] B. When the grid frequency is running at (50.000-E ’ )Hz~(50.000+E)Hz, the secondary frequency regulation will no longer be carried out with the rated frequency as the target, unless it is for the purpose of making the grid frequency more accurately reflect the peak demand of the grid. In other words, when the grid frequency operates in this range, let the primary frequency regulation of the grid play the main frequency regulation role. When the grid-connected power output is greater than the load power (for example, when the consumption of new energy is the main problem to be solved by the grid), the grid frequency is stabilized at a frequency value larger than the rated frequency through the differential regulation of the primary frequency regulation; when the grid load is at peak time and the load is greater than the grid-connected power output (for example, when the power supply is the main problem to be solved by the grid), the grid frequency is stabilized at a frequency value smaller than the rated frequency through the differential regulation of the primary frequency regulation. The secondary frequency regulation of the grid no longer carries out the regulation process with the purpose of adjusting the grid frequency to the rated frequency, but as an auxiliary means, with the grid frequency being able to more accurately reflect the peak demand of the grid as the regulation goal. The higher the current and expected subsequent grid output is greater than the load, the grid frequency is maintained at (50.000-E ’ )Hz~(50.000+E)Hz higher frequency value; on the contrary, the higher the current and expected subsequent power grid load is than the output, the power grid frequency is maintained at (50.000-E ’ )Hz~(50.000+E)Hz lower frequency value.

[0042] C. When the grid frequency exceeds the range of (50.000-E')Hz to (50.000+E)Hz, the secondary frequency regulation starts and adjusts the grid frequency to between (50.000-E')Hz and (50.000+E)Hz. The specific frequency point to which it is adjusted depends on the peak-shaving demand of the grid. When the grid peak-shaving requires more grid-connected output, the target frequency is lower than the rated frequency. The more grid-connected output is required, the lower the target frequency is; when the grid peak-shaving requires a larger load, the target frequency is higher than the rated frequency. The more load is required, the higher the target frequency is. Specifically, in terms of the secondary frequency regulation strategy, it is necessary to change the calculation method of ACE, which is based on secondary frequency regulation. At present, the calculation of ACE is basically ACE=k△f+△P, where k is the frequency regulation coefficient or the regional frequency deviation coefficient, △f is the frequency deviation, and △P is the deviation between the preset value and the actual value of the active power of the tie line (in some automatic generation control (AGC) control modes, ACE calculation does not consider the tie line power deviation, then △P=0). What needs to be changed is the calculation of △f, and the formula △f=ff 0 (f is the actual frequency of the power grid, f 0 is the rated frequency of the power grid) is modified to The calculation formula of △f is:

[0043] in, is the rated frequency.

[0044] When the grid frequency is between (50.000-E')Hz and (50.000+E)Hz, the ACE=k△f caused by the frequency deviation from the rated frequency is directly set to 0, and no secondary frequency adjustment is performed due to the frequency deviation. However, it does not exclude the power adjustment based on the grid frequency to more accurately reflect the grid peak-shaving demand or adjust the interconnection line power; when the grid frequency exceeds (50.000-E')Hz to (50.000+E)Hz, the ACE calculated by the original calculation method should also be subtracted from the ACE deviation caused by the frequency range (k×E or k×E'). Under this calculation principle, it does not exclude the application of various situations based on the k value, segmented processing or other nonlinear time-varying means in the original ACE calculation method. As long as the ACE adjustment caused by the frequency deviation in the frequency range of (50.000-E')Hz to (50.000+E)Hz is no longer included in the calculation of ACE, the requirements of the patent solution can be met.

[0045] D. The tertiary frequency regulation for economic operation and tie line power adjustment still follows the original control strategy. However, the tertiary frequency regulation was originally carried out when the grid frequency was stable near the rated frequency. The improved scheme allows the tertiary frequency regulation to be carried out as long as the grid frequency is running between (50.000-E')Hz and (50.000+E)Hz. It is worth mentioning that some people also classify the tie line power adjustment and the adjustment to maintain the tie line power as secondary frequency regulation or carry out in the secondary frequency regulation process. In this case, the analysis and processing shall be carried out according to the above clause C.

[0046] The terminal device provided in an embodiment of the present invention. The terminal device of this embodiment includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of the modules / units in the above-mentioned device embodiments are implemented.

[0047] The computer program may be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to accomplish the present invention.

[0048] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0049] The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0050] The memory may be used to store the computer programs and / or modules, and the processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory and calling the data stored in the memory.

[0051] If the module / unit integrated in the terminal device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0052] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A secondary frequency regulation control method for a power grid with a non-rated frequency as a regulation target, characterized in that: include: Improve the primary frequency regulation capability of the power grid, and determine the dead zone of the secondary frequency regulation of the power grid based on the frequency fluctuation range of the power grid and the power disturbance faced by the power grid; The grid is subjected to secondary frequency modulation with the goal of the grid frequency entering the dead zone range, thereby realizing secondary frequency modulation operation control of the grid.

2. The power grid secondary frequency regulation control method with non-rated frequency as the regulation target according to claim 1, characterized in that: In the process of performing secondary frequency regulation on the power grid with the goal of the power grid frequency entering the dead zone, the frequency accurately reflects the peak-shaving demand of the power grid as the regulation goal.

3. The method for controlling secondary frequency regulation of a power grid with non-rated frequency as the regulation target according to claim 2, characterized in that: In the process of performing secondary frequency modulation on the power grid with the power grid frequency entering the dead zone range as the goal, when the power grid frequency runs at (50.000-E ’ )Hz~(50.000+E)Hz, if the current and expected subsequent power generation output of the power grid is higher than the load power, the power grid frequency is maintained at a higher frequency value of (50.000-E')Hz~(50.000+E)Hz; conversely, the current and expected subsequent power load power is higher than the power generation output, the power grid frequency is maintained at a lower frequency value of (50.000-E')Hz~(50.000+E)Hz; where E is the upper limit threshold value of the secondary frequency regulation frequency dead zone when the frequency increases; E' is the lower limit threshold value of the secondary frequency regulation frequency dead zone when the frequency decreases.

4. The method for controlling secondary frequency regulation of a power grid with non-rated frequency as a regulation target according to claim 1, characterized in that: The principle for determining the dead zone of the secondary frequency regulation of the power grid is as follows: in the daily operation of the power grid, the power grid frequency is stabilized at around the rated frequency of (50.000-E') Hz to (50.000+E) Hz by relying solely on the primary frequency regulation of the power grid; when the power grid frequency is stably operating at (50.000-E') Hz to (50.000+E) Hz, for large power disturbance events that may occur in the power grid, the frequency safety of the power grid is still ensured by relying on the subsequent primary and secondary frequency regulation capabilities of the power grid and relevant stability measures of the power grid; E and E' are dynamically adjusted in a timely manner according to the actual operation mode of the power grid and other situations that affect frequency safety; wherein E is the upper limit threshold value of the secondary frequency regulation dead zone when the frequency increases; and E' is the lower limit threshold value of the secondary frequency regulation dead zone when the frequency decreases.

5. The method for controlling secondary frequency regulation of a power grid with non-rated frequency as a regulation target according to claim 1, characterized in that: The improvement of the primary frequency regulation capability of the power grid is specifically as follows: Obtaining a primary frequency modulation dead zone of a non-renewable energy grid-connected power source in the power grid; setting a primary frequency modulation dead zone of a new energy grid-connected power source in the power grid based on the primary frequency modulation dead zone of the non-renewable energy grid-connected power source; wherein the absolute value of the primary frequency modulation dead zone of a first preset proportion of new energy grid-connected power sources in the power grid is smaller than the absolute value of the primary frequency modulation dead zone of all or a second preset proportion of non-renewable energy grid-connected power sources in the power grid; Obtain the installed capacity and daily power operation range of the new energy grid-connected power supply with primary frequency regulation capability in the power grid, and the unbalanced power situation of the power grid for 1 to 15 minutes on a daily basis; based on the installed capacity and daily power operation range of the new energy grid-connected power supply with primary frequency regulation capability, and the unbalanced power situation of the power grid for 1 to 15 minutes on a daily basis, set the primary frequency regulation difference rate of the new energy grid-connected power supply in the power grid in combination with the primary frequency regulation frequency dead zone of the new energy grid-connected power supply in the power grid; Based on the primary frequency modulation dead zone and primary frequency modulation difference rate of the renewable energy grid-connected power supply, the primary frequency modulation of the renewable energy grid-connected power supply is realized; based on the primary frequency modulation dead zone and primary frequency modulation difference rate of the non-renewable energy grid-connected power supply, the primary frequency modulation of the non-renewable energy grid-connected power supply is realized; based on the primary frequency modulation of the renewable energy grid-connected power supply and the primary frequency modulation of the non-renewable energy grid-connected power supply, the frequency modulation operation control of the power grid is realized.

6. The method for controlling secondary frequency regulation of a power grid with non-rated frequency as a regulation target according to claim 1, characterized in that: The specific adjustment process of the secondary frequency regulation with the grid frequency entering the secondary frequency regulation dead zone range as the adjustment target is: when the grid frequency exceeds the set grid dead zone frequency range, the regional control deviation ACE calculation method based on the secondary frequency regulation is adjusted, and the secondary frequency regulation is performed accordingly to achieve the grid frequency being adjusted to within the grid secondary frequency regulation dead zone frequency range.

7. The method for controlling secondary frequency regulation of a power grid with non-rated frequency as a regulation target according to claim 6, characterized in that: The regional control deviation ACE based on the secondary frequency modulation is regulated as follows: When the grid frequency exceeds the range of (50.000-E') Hz to (50.000+E) Hz, the secondary frequency regulation starts to adjust the grid frequency to between (50.000-E') Hz and (50.000+E) Hz; and the calculation method of the regional control deviation ACE based on the secondary frequency regulation is changed, and the regional control deviation ACE is: ACE=k△f+△P Wherein, k is the frequency modulation coefficient or the regional frequency deviation coefficient, △f is the frequency deviation, and △P is the deviation between the preset value and the actual value of the active power of the tie line; in, is the rated frequency.

8. A secondary frequency regulation control system for a power grid with non-rated frequency as the regulation target, characterized in that: include: A determination module, wherein the determination module improves the primary frequency regulation capability of the power grid and determines a dead zone of the secondary frequency regulation of the power grid based on the frequency fluctuation range of the power grid and the power disturbance amount faced by the power grid; A frequency modulation module, wherein the frequency modulation module performs secondary frequency modulation on the power grid when the power grid frequency enters the dead zone range, thereby realizing secondary frequency modulation operation control of the power grid.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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