Self-adaptive frequency voltage stability control method and system for isolated network of regional power grid

Abstract

The invention discloses a self-adaptive frequency voltage stability control method and system for an isolated network of a regional power grid, and the method comprises the steps: obtaining the power vacancy and system inertia of the passive isolated network operation of the regional power grid, and calculating the initial frequency change rate of the isolated network based on the power vacancy and system inertia; determining a control demand of the power system based on the initial frequency change rate of the isolated network; and if the current power system has the control requirement, performing stable control on the frequency voltage of the isolated network by combining the real-time frequency of the power system. According to the invention, based on system frequency and voltage change conditions, controllable resources of an isolated network area are reasonably utilized, and the frequency stability probability of the isolated network is improved; through the real-time change condition of the frequency voltage of the system, the multi-wheel grading fine coordination control of the new energy, the traditional unit and the load in the isolated network is realized, and the operation stability of the isolated network system is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid stability control, and in particular to a method and system for adaptive frequency and voltage stability control of an isolated regional power grid. Background Art

[0002] With the construction of new power systems, the proportion of wind and solar power in the system continues to increase, and some regions are gradually dominated by wind and solar power. Compared with traditional power transmission, the regional stability characteristics have undergone profound changes. For areas with a high proportion of new energy transmission, when the power grid is passively isolated, the frequency stability problem becomes the main factor affecting whether the isolated grid system can maintain stable operation.

[0003] When the local power grid is passively isolated, the frequency and voltage of the power grid are greatly affected by repeated voltage crossing of new energy sources, transient overvoltage disconnection from the grid, and frequency limit disconnection from the grid. Generally speaking, the higher the penetration rate of new energy sources, the worse the system frequency support effect. Therefore, new energy sources cannot be used as the main control object for frequency stability. At the same time, the reactive support provided during the low-voltage crossing process may further increase the voltage, causing overvoltage disconnection of new energy units or overvoltage tripping of traditional units. Therefore, it is still necessary to rely on the original low-frequency, over-frequency and other protection rounds of setting, and make full use of the balance and adjustment capabilities of isolated traditional units to maintain system power balance and frequency stability. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above existing problems, the present invention is proposed.

[0006] Therefore, the present invention provides a method and system for adaptive frequency and voltage stability control of an isolated regional power grid to solve the problems mentioned in the background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, an embodiment of the present invention provides a method for adaptive frequency and voltage stability control of an isolated network of a regional power grid, comprising: obtaining a power shortage and a system inertia of a passive isolated network operation of the regional power grid, and calculating an initial frequency change rate of the isolated network based on the power shortage and the system inertia;

[0009] Determining a control demand of the power system based on the initial frequency change rate of the isolated grid;

[0010] If there is a control demand for the current power system, the frequency and voltage of the isolated grid will be stably controlled in combination with the real-time frequency of the power system.

[0011] As a preferred solution of the method for adaptive frequency and voltage stability control of isolated grid in regional power grid of the present invention, the control demand of the power system determined based on the initial frequency change rate of the isolated grid includes:

[0012] If the initial frequency change rate of the isolated grid is less than a preset threshold, the power system does not have a control frequency and voltage demand;

[0013] If the initial frequency change rate of the isolated grid is not less than a preset threshold, there is a risk of frequency fluctuation in the power system, and the frequency and voltage of the isolated grid need to be stably controlled.

[0014] As a preferred solution of the method for adaptively controlling the frequency and voltage stability of an isolated grid in a regional power grid according to the present invention, the stable control of the frequency and voltage of the isolated grid includes:

[0015] When the initial frequency change rate of the isolated grid is not less than the preset threshold, if the current actual frequency of the power system is less than the first frequency limit and greater than the second frequency limit, voltage control is performed; if the current actual frequency of the power system is greater than the first frequency limit and less than the second frequency limit, over-frequency unit cutting control is performed; if the current actual frequency of the power system is less than the second frequency limit, under-frequency load reduction control is performed.

[0016] As a preferred solution of the method for adaptive frequency and voltage stability control of isolated grid in regional power grid described in the present invention, the over-frequency unit cutting control includes:

[0017] When the initial frequency change rate of the isolated grid is not less than the preset threshold, and the actual frequency of the current power system is not less than the first frequency limit and less than the third frequency limit, and the actual frequency of the power system is within the frequency tolerance range of new energy, new energy is preferentially cut off in rounds and grades until all new energy units are cut off;

[0018] When the initial frequency change rate of the isolated grid is not less than a preset threshold value, and the actual frequency of the current power system is not less than the third frequency limit, the conventional generating units are switched in turns according to the measured frequency change rate.

[0019] As a preferred scheme of the regional power grid isolated network adaptive frequency and voltage stability control method described in the present invention, the low-frequency load reduction control includes: when the actual frequency of the power system is not greater than the second frequency limit, the load is cut in rounds, and the load is cut at an accelerated rate according to the measured frequency change rate.

[0020] As a preferred scheme of the regional power grid isolated network adaptive frequency and voltage stability control method described in the present invention, the voltage control includes: if the actual frequency of the current power system is not less than the second frequency limit and not greater than the third frequency limit, after a preset time delay, the voltage control is opened, otherwise the control is ended.

[0021] As a preferred solution of the regional power grid isolated network adaptive frequency and voltage stability control method described in the present invention, it also includes: when the frequency is not less than the first frequency and not greater than the third frequency limit, and the bus voltage of the power system and the power generation station is greater than the first voltage, the new energy units are preferentially cut off, and the overvoltage units are cut off step by step;

[0022] When the voltage recovers to above the second voltage, the low-voltage load reduction function is opened, and when the system frequency is lower than the second frequency, if the voltage is lower than the third voltage, each round of low-voltage load reduction action is performed.

[0023] In a second aspect, the present invention provides a regional power grid isolated network adaptive frequency and voltage stability control system, comprising:

[0024] A calculation module, used to obtain the power shortage and system inertia of the passive isolated network operation of the regional power grid, and calculate the initial frequency change rate of the isolated network based on the power shortage and system inertia;

[0025] A demand determination module, used for determining the control demand of the power system based on the initial frequency change rate of the isolated grid;

[0026] The control module is used to stabilize the frequency and voltage of the isolated grid in combination with the real-time frequency of the power system if there is a control demand in the current power system.

[0027] In a third aspect, the present invention provides an electronic device, comprising:

[0028] Memory and processor;

[0029] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the regional power grid isolated network adaptive frequency and voltage stability control method are implemented.

[0030] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, can implement the steps of the regional power grid isolated network adaptive frequency and voltage stability control method.

[0031] Compared with the prior art, the present invention has the following beneficial effects: based on the changes in system frequency and voltage, the present invention rationally utilizes the controllable resources in the isolated grid area to improve the probability of frequency stability in the isolated grid; through the real-time changes in system frequency and voltage, it realizes the round-by-round and graded refined coordinated control of new energy, traditional units and loads in the isolated grid, effectively improving the operating stability of the isolated grid system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0033] Figure 1 A method flow chart of a method and system for adaptive frequency and voltage stability control of an isolated grid of a regional power grid according to an embodiment of the present invention;

[0034] Figure 2 A control flow diagram of a method and system for adaptive frequency and voltage stability control of an isolated grid of a regional power grid according to an embodiment of the present invention, taking the output of a unit in the power grid as an example of being greater than the load;

[0035] Figure 3 This is a control effect diagram of a method and system for adaptive frequency and voltage stability control of an isolated regional power grid according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0039] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0040] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0041] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, 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 also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication 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.

[0042] Example 1

[0043] Reference Figures 1-2 , is an embodiment of the present invention, which provides a method for controlling frequency and voltage stability of an isolated power grid in a regional power grid adaptively, such as Figure 1 Shown include:

[0044] S100: Obtain the power shortage and system inertia of the passive isolated network operation of the regional power grid, and calculate the initial frequency change rate of the isolated network based on the power shortage and the system inertia;

[0045] S200: Determine the control demand of the power system based on the initial frequency change rate of the isolated grid;

[0046] S300: If there is a control demand for the current power system, the frequency and voltage of the isolated grid are stably controlled in combination with the real-time frequency of the power system.

[0047] It should be noted that for areas with a high proportion of renewable energy transmission, when the power grid is passively isolated, the frequency stability problem becomes the main factor affecting whether the isolated system can maintain stable operation. When the local power grid is passively isolated, the frequency and voltage of the power grid are greatly affected by repeated voltage crossing of new energy, transient overvoltage disconnection, and frequency limit disconnection. Generally speaking, the higher the penetration rate of renewable energy, the worse the system frequency support effect. The present invention is based on the real-time changes in system frequency and voltage in areas containing renewable energy, with the purpose of retaining the main regulating units and ensuring the supply of main loads, and the round-by-round and graded coordinated control of new energy, traditional units and loads in the isolated network is improved. The probability of frequency stability in the isolated network is improved.

[0048] Reference Figure 2 In an embodiment of the present application, determining the control demand of the power system based on the initial frequency change rate of the isolated grid includes:

[0049] If the initial frequency change rate of the isolated grid is less than the preset threshold, there is no demand for controlling frequency and voltage in the power system;

[0050] If the initial frequency change rate of the isolated grid is not less than the preset threshold, there is a risk of frequency fluctuation in the power system, and the frequency and voltage of the isolated grid need to be stably controlled.

[0051] Specifically, the initial frequency change rate df / dt_sys of the regional power grid passively jumping into the isolated grid is calculated as:

[0052]

[0053] Among them, ⊿P e is the power delivered by the passive isolated grid system, H sys It is the sum of the inertia of traditional units in the isolated grid. New energy units do not participate in the inertia calculation.

[0054] In an optional embodiment, if the preset threshold is 2 Hz / s, when the initial df / dt_sys<2 Hz / s, consider not cutting off the new energy unit and mainly rely on the speed regulation capability control of the traditional unit.

[0055] In an embodiment of the present application, stabilizing the frequency and voltage of the isolated grid includes:

[0056] When the initial frequency change rate of the isolated grid is not less than the preset threshold, if the current actual frequency of the power system is less than the first frequency limit and greater than the second frequency limit, voltage control is performed; if the current actual frequency of the power system is greater than the first frequency limit and less than the second frequency limit, over-frequency unit cutting control is performed; if the current actual frequency of the power system is less than the second frequency limit, under-frequency load reduction control is performed.

[0057] In the embodiment of the present application, the over-frequency switching control includes:

[0058] When the initial frequency change rate of the islanded power grid is not less than the preset threshold, and the actual frequency of the current power system is not less than the first frequency limit and less than the third frequency limit, and the actual frequency of the power system is within the new energy frequency tolerance range, new energy is preferentially cut in rounds and levels until all new energy units are cut off;

[0059] When the initial frequency change rate of the islanded power grid is not less than the preset threshold, and the actual frequency of the current power system is not less than the third frequency limit, traditional units are cut in rounds according to the measured frequency change rate.

[0060] In an optional embodiment, for over-frequency cutting of new energy units: when df / dt_sys≥df0 and fa1≤f<fa2, within the new energy frequency tolerance range, new energy is preferentially cut in rounds and levels until all new energy units are cut off; for over-frequency cutting of traditional units: when df / dt_sys<df0≥df0 and f≥fa2, traditional units are cut in rounds according to the measured df / dt_mes.

[0061] In an optional embodiment, the switching of traditional units also includes a fast tripping area and a slow tripping area. Small units without frequency modulation capabilities are preferentially selected in the fast tripping area, and large units are selected in the slow tripping area, and hydropower units with strong regulation capabilities are retained.

[0062] In the embodiment of the present application, the under-frequency load shedding control includes: when the actual frequency of the power system is not greater than the second frequency limit, loads are cut in rounds, and the load shedding is accelerated according to the measured frequency change rate.

[0063] In an optional embodiment, when f≤fb1, loads are cut in rounds, and the load shedding is accelerated according to the measured frequency change rate df / dt_mes.

[0064] In an optional embodiment, when accelerating the load shedding according to the measured frequency change rate, in order to prevent frequency hovering, long-delay action rounds can be set at two frequency points, namely the fourth frequency limit and the fifth frequency limit.

[0065] In the embodiment of the present application, the voltage control includes: if the actual frequency of the current power system is not less than the second frequency limit and not greater than the third frequency limit, after a preset time delay, the voltage control is enabled, otherwise the control ends.

[0066] In the embodiment of the present application, it further includes: when the frequency is not less than the first frequency and not greater than the third frequency limit, and the bus voltages of the power system and the power generation station are greater than the first voltage, new energy units are preferentially cut, and the over-voltage units are controlled to be cut off step by step;

[0067] When the voltage recovers above the second voltage and the system frequency is less than the second frequency, if the voltage is less than the third voltage, each round of low-voltage load shedding actions is performed.

[0068] It should be noted that the values of the first frequency and the second frequency can be set according to the actual operation of the system. In the embodiments of the present application, the first frequency can be 50.5 Hz and the second frequency can be 49.5 Hz.

[0069] In an alternative embodiment, when fb1 ≤ f ≤ fa2 and after a delay of Ts, voltage control is allowed to be enabled. When the frequency is between 50.5 and fa2 and the bus voltages of the system and the power generation station are greater than Ugy, new energy units are preferentially disconnected, and overvoltage units are controlled to be disconnected step by step; after a system fault occurs, when the voltage recovers above Uyy, the low-voltage load shedding function is enabled, and at the same time, only when the system frequency is lower than 49.5 Hz and U < Uqy are the low-voltage load shedding actions of each round allowed.

[0070] The above is a schematic solution of a method for controlling the self-adaptive frequency and voltage stability of an islanded regional power grid in this embodiment. It should be noted that the technical solution of the system for controlling the self-adaptive frequency and voltage stability of an islanded regional power grid belongs to the same concept as the above-mentioned method for controlling the self-adaptive frequency and voltage stability of an islanded regional power grid. For the details not described in detail in the technical solution of the system for controlling the self-adaptive frequency and voltage stability of an islanded regional power grid in this embodiment, reference can be made to the description of the technical solution of the above-mentioned method for controlling the self-adaptive frequency and voltage stability of an islanded regional power grid.

[0071] A system for controlling the self-adaptive frequency and voltage stability of an islanded regional power grid in this embodiment includes:

[0072] A calculation module, configured to obtain the power deficit and the system inertia of the islanded operation of the regional power grid passively, and calculate the initial frequency change rate of the islanded grid based on the power deficit and the system inertia;

[0073] A demand determination module, configured to determine the control demand of the power system based on the initial frequency change rate of the islanded grid;

[0074] A control module, configured to, if there is a control demand in the current power system, perform stable control on the frequency and voltage of the islanded grid in combination with the real-time frequency of the power system.

[0075] This embodiment also provides an electronic device applicable to the situation of the method for controlling the self-adaptive frequency and voltage stability of an islanded regional power grid, including:

[0076] A memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the method for controlling the self-adaptive frequency and voltage stability of an islanded regional power grid as proposed in the above embodiment.

[0077] This embodiment also provides a storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the method for realizing the self-adaptive frequency and voltage stability control of an islanded regional power grid as proposed in the above embodiment.

[0078] The storage medium proposed in this embodiment and the method for realizing the self-adaptive frequency and voltage stability control of an islanded regional power grid proposed in the above embodiment belong to the same inventive concept. For the technical details not described in detail in this embodiment, reference can be made to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0079] From the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software and necessary general hardware. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a floppy disk, read-only memory (ROM), random access memory (RAM), flash memory (FLASH), hard disk, or optical disc of a computer, including several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods of the various embodiments of the present invention.

[0080] Embodiment 2

[0081] Refer to Figure 3 , which is an embodiment of the present invention. The difference between this embodiment and the first embodiment is that, taking the case where the output of the units in the power grid is greater than the load as an example, the self-adaptive frequency and voltage stability control of an islanded regional power grid containing new energy is carried out to verify the beneficial effects of the present invention.

[0082] In this embodiment, when the initial df / dt_sys≥2Hz / s and at the same time the islanded grid frequency f≥51.0Hz, first compare the system output power ⊿P e before passive islanding with the total output P n of the new energy units before the accident. When ⊿P e ≥P n , all new energy units are preferentially cut off; when ⊿Pe<Pn, the new energy units are cut off in 6 rounds, which are respectively:

[0083] When f≥51.0Hz, the first group of new energy units are cut off after a delay of 0.2s;

[0084] When f≥51.2Hz, the second group of new energy units are cut off after a delay of 0.2s;

[0085] f ≥ 51.4 Hz, delay 0.2 s to disconnect the third group of new energy units;

[0086] f ≥ 51.6 Hz, delay 0.2 s to disconnect the fourth group of new energy units;

[0087] f ≥ 51.8 Hz, delay 0.2 s to disconnect the fifth group of new energy units;

[0088] f ≥ 52.0 Hz, delay 0.2 s to disconnect all new energy units.

[0089] In this embodiment, when disconnecting new energy units, the new energy units that do not have primary frequency regulation and inertia support are preferentially disconnected, and the amount of units disconnected in each round can be kept basically average.

[0090] When the initial df / dt of the islanded power system ≥ 2 Hz / s and the system frequency is greater than 52 Hz, control to disconnect traditional units. According to the real-time df / dt of the system, it is divided into a fast action area and a slow action area. Small-capacity units are disconnected in the fast action area, and large units are disconnected in the slow action area:

[0091] ① First, sort the units in the islanded power system. Preferentially retain the hydropower units with the best primary frequency regulation ability and larger output. Then, sort the remaining units from small to large according to their capacities. The small-capacity units and the units with poor speed regulation ability (or the units that have not carried out on-site governor test verification) are put into the fast action area; the units with larger capacities are put into the slow action area. For example, if the unit capacities are: G1 < G2 < G3 < G4, and the frequency regulation abilities are: G1 < G2 < G4 < G3; the comprehensive sorting is: G1, G2, G4, G3.

[0092] ② When the system frequency is greater than 52 Hz,

[0093] When the measured df / dt ≥ 5 Hz / s, delay 0.1 s to disconnect 1 unit in the fast action area;

[0094] When the measured df / dt ≥ 3 Hz / s, delay 0.2 s to disconnect 1 unit in the fast action area;

[0095] When the measured df / dt ≥ 2 Hz / s, delay 0.3 s to disconnect 1 unit in the fast action area;

[0096] When the measured df / dt ≥ 1 Hz / s, delay 0.5 s to disconnect 1 unit in the slow action area;

[0097] When df / dt < 1 Hz / s and the system frequency is still greater than 52 Hz, delay 1 s to disconnect 1 unit in the slow action area.

[0098] ③ When the system frequency is less than 52 Hz, consider not to disconnect traditional units.

[0099] Utilize frequency and df / dt to accelerate load shedding, and increase the interval and delay in each round:

[0100] f≤49.0Hz, delay 0.3s to cut off the first round of load;

[0101] f≤49.0Hz, measured df / dt≥2Hz / s, delay 0.2s to advance the second round;

[0102] f≤49.0Hz, measured df / dt≥3Hz / s, delay 0.2s to advance the third round;

[0103] f≤48.6Hz, delay 0.3s to cut the second round of load;

[0104] f≤48.2Hz, delay 0.3s to cut the third round of load;

[0105] f≤47.8Hz, delay 0.3s to cut the fourth load;

[0106] f≤47.4Hz, delay 0.3s to cut the fifth load;

[0107] f≤47.0Hz, delay 0.3s to cut off the sixth load;

[0108] Long delay action wheel:

[0109] f≤48.5Hz, delay 2s to cut off the 7th load;

[0110] f≤49Hz, delay 5s to cut off the 8th round of load.

[0111] Voltage control is allowed to be opened only when the system frequency is stable in the range of 48-52Hz for more than 2s.

[0112] Overvoltage control: When the frequency is between 50.5 and 52 Hz and the bus voltage of the system and power station is greater than 1.2 pu, the new energy units are switched first, and the units with a capacity less than 20% of the system load capacity are controlled step by step;

[0113] Low voltage control: After a system failure, the low voltage load shedding function is enabled when the voltage recovers to above 0.7pu. At the same time, each round of low voltage load shedding is allowed only when the system frequency is lower than 49.5Hz:

[0114] U≤0.85pu, f≤49.5Hz, delay 2s to cut the first round of load;

[0115] U≤0.80pu, f≤49.5Hz, delay 2s to cut off the second round of load;

[0116] U≤0.75pu, f≤49.5Hz, delay 2s to cut the third round of load;

[0117] U≤0.70pu, f≤49.5Hz, delay 2s to cut off the fourth round of load.

[0118] After adopting the above control method, the frequency change of the system after the passive isolated grid operation of a certain area power grid is as follows: Figure 3 As shown, under the conventional system frequency and voltage control configuration method, the frequency of the isolated grid system fluctuates greatly and becomes unstable; the present invention, based on the real-time changes in the system frequency and voltage, with the purpose of retaining the main regulating units and ensuring the supply of the main loads, performs refined coordinated control of the new energy, traditional units and loads in the isolated grid in stages, so that the isolated grid system can quickly recover stability and achieve good application effects.

[0119] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for adaptive frequency and voltage stability control of isolated regional power grids, characterized in that: include: Obtaining the power shortage and system inertia of the passive isolated grid operation of the regional power grid, and calculating the initial frequency change rate of the isolated grid based on the power shortage and system inertia; Determining a control demand of the power system based on the initial frequency change rate of the isolated grid; If there is a control demand for the current power system, the frequency and voltage of the isolated grid will be stably controlled in combination with the real-time frequency of the power system.

2. The method for controlling the frequency and voltage stability of an isolated grid in a regional power grid according to claim 1, characterized in that: The determining of the control demand of the power system based on the isolated grid initial frequency change rate comprises: If the initial frequency change rate of the isolated grid is less than a preset threshold, the power system does not have a control frequency and voltage demand; If the initial frequency change rate of the isolated grid is not less than a preset threshold, there is a risk of frequency fluctuation in the power system, and the frequency and voltage of the isolated grid need to be stably controlled.

3. The method for controlling the frequency and voltage stability of an isolated grid in a regional power grid according to claim 2, characterized in that: The stable control of the frequency and voltage of the isolated grid includes: When the initial frequency change rate of the isolated grid is not less than the preset threshold, if the current actual frequency of the power system is less than the first frequency limit and greater than the second frequency limit, voltage control is performed; if the current actual frequency of the power system is greater than the first frequency limit and less than the second frequency limit, over-frequency unit cutting control is performed; if the current actual frequency of the power system is less than the second frequency limit, under-frequency load reduction control is performed.

4. The method for controlling the frequency and voltage stability of an isolated grid in a regional power grid according to claim 3, characterized in that: The over-frequency cutting unit control includes: When the initial frequency change rate of the isolated grid is not less than the preset threshold, and the actual frequency of the current power system is not less than the first frequency limit and less than the third frequency limit, and the actual frequency of the power system is within the frequency tolerance range of new energy, new energy is preferentially cut off in rounds and grades until all new energy units are cut off; When the initial frequency change rate of the isolated grid is not less than a preset threshold value, and the actual frequency of the current power system is not less than the third frequency limit, the conventional generating units are switched in turns according to the measured frequency change rate.

5. The method for controlling the frequency and voltage stability of an isolated grid in a regional power grid according to claim 4, characterized in that: The low-frequency load shedding control includes: when the actual frequency of the power system is not greater than the second frequency limit, shedding the load in stages, and accelerating the load shedding according to the measured frequency change rate.

6. The method for controlling the frequency and voltage stability of an isolated grid in a regional power grid according to claim 5, characterized in that: The voltage control includes: if the actual frequency of the current power system is not less than the second frequency limit and not greater than the third frequency limit, after a preset time delay, the voltage control is opened, otherwise the control is ended.

7. The method for controlling the frequency and voltage stability of an isolated grid in a regional power grid according to claim 6, characterized in that: Also includes: When the frequency is not less than the first frequency and not greater than the third frequency limit, and the bus voltage of the power system and the power station is greater than the first voltage, the new energy units are cut off first, and the overvoltage units are cut off step by step; When the voltage recovers to above the second voltage, the low-voltage load reduction function is opened, and when the system frequency is lower than the second frequency, if the voltage is lower than the third voltage, each round of low-voltage load reduction action is performed.

8. A regional power grid isolated network adaptive frequency and voltage stability control system, characterized in that: include: A calculation module, used to obtain the power shortage and system inertia of the passive isolated network operation of the regional power grid, and calculate the initial frequency change rate of the isolated network based on the power shortage and system inertia; A demand determination module, used for determining the control demand of the power system based on the initial frequency change rate of the isolated grid; The control module is used to stabilize the frequency and voltage of the isolated grid in combination with the real-time frequency of the power system if there is a control demand in the current power system.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the regional power grid isolated network adaptive frequency and voltage stability control method described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the method for adaptive frequency and voltage stability control of an isolated regional power grid as described in any one of claims 1 to 7.

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