Real-time adjustment method and device for overvoltage and reactive power compensation strategy of ac substation

Abstract

The application discloses a real-time adjustment method and device for overvoltage and reactive power compensation strategy of an alternating current substation. The method comprises the following steps: acquiring equivalent electrical quantity parameters of a first unit and equivalent electrical quantity parameters of a second unit connected with the alternating current substation in real time according to an equivalent model of an interconnection system; outputting voltage of a compensation node in a near region of a main transformer of the alternating current substation, voltage of a compensation node of the main transformer of the alternating current substation and reactive power electrical quantity flowing between the near region of the main transformer of the alternating current substation and the main transformer according to the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit by using the equivalent model of the interconnection system; determining a flow direction of the reactive power according to a preset criterion and the reactive power electrical quantity; and determining an adjustment scheme of the reactive power compensation strategy according to the flow direction of the reactive power.

Description

Technical Field

[0001] This invention relates to the field of safe and stable operation technology of AC / DC hybrid power grids, and more specifically, to a real-time adjustment method and apparatus for overvoltage and reactive power compensation strategies in AC substations. Background Technology

[0002] AC / DC hybrid power grids possess powerful transmission capabilities, greatly alleviating the problem of uneven distribution of energy and load across regions in my country, and have become a new form of power grid development in my country. However, due to the complex structure of AC / DC hybrid power grids, the mutual influence between AC and DC systems is becoming increasingly significant, posing a severe challenge to the safe and stable operation of large power grids.

[0003] The configuration of reactive power compensation equipment in AC / DC hybrid power grids is closely related to the system's operating voltage level. Overvoltage operation accelerates the aging of electrical equipment insulation, leading to equipment damage and shutdown, and potentially causing system failures or even instability. Therefore, proper configuration of reactive power compensation equipment can effectively improve the system's reactive power distribution and voltage level, mitigate various power grid safety risks caused by overvoltage operation, and enhance the stability of AC / DC hybrid power grids.

[0004] Currently, the adjustment of overvoltage and reactive power compensation strategies in AC substations in AC / DC hybrid power grids mainly relies on expert experience, which cannot achieve real-time adjustment. There is an urgent need to propose a real-time adjustment method for the main transformer and its near-zone voltage and reactive power compensation strategies during AC substation overvoltage operation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and apparatus for real-time adjustment of overvoltage and reactive power compensation strategies in AC substations.

[0006] According to one aspect of the present invention, a method for real-time adjustment of overvoltage and reactive power compensation strategies in AC substations is provided, comprising:

[0007] Based on the equivalent model of the interconnected system, the equivalent electrical quantity parameters of the first unit connected to the AC substation and the equivalent electrical quantity parameters of the second unit are obtained in real time.

[0008] Using the equivalent model of the interconnected system, based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit, the voltage of the compensation node of the main transformer near the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power electrical quantity flowing between the main transformer near the AC substation and the main transformer are output.

[0009] The direction of reactive power flow is determined based on pre-set criteria and reactive power electrical quantities.

[0010] Based on the direction of reactive power flow, determine the adjustment scheme of reactive power compensation strategy.

[0011] Optionally, using the equivalent model of the interconnected system, based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit, the voltage of the AC substation main transformer near-zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power electrical quantity flowing between the AC substation main transformer near-zone and the main transformer are output, including:

[0012] Calculate the voltage of the near-zone compensation node of the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the power angle of the first unit relative to the second unit based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit.

[0013] Based on the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the power angle of the first unit relative to the second unit, calculate the reactive power electrical quantity flowing between the main transformer near the AC substation and the main transformer.

[0014] Optionally, using the equivalent model of the interconnected system, based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit, the calculation formulas for the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power electrical quantity flowing between the near zone of the main transformer and the main transformer of the AC substation are as follows:

[0015] Calculate the direct connection impedance x between the first unit and the second unit according to equation (1):

[0016]

[0017] Calculate the power angle δ according to equation (2):

[0018]

[0019] Calculate the voltage of the near-zone compensation node of the main transformer in the AC substation according to equations (3) to (6).

[0020]

[0021]

[0022]

[0023]

[0024] Calculate the main transformer compensation node voltage of the AC substation according to equations (7) to (8).

[0025]

[0026]

[0027] Calculate the reactive power exchange Q between the near zone of the main transformer and the main transformer in the AC substation according to equations (9) to (11):

[0028]

[0029]

[0030]

[0031] Where E1 is the equivalent electromotive force of the first unit, Let E1 be the equivalent potential vector form of the first unit, x1 be the equivalent reactance of the first unit, and E2 be the equivalent potential of the second unit. x1 is the equivalent potential vector form of the second unit, x2 is the equivalent reactance of the second unit, P is the active power transmitted between the two systems, x0 is the electrical distance between the main transformer and the adjacent section of the AC substation, and x... 01 Equivalent parameters of reactive power compensation capacity in the vicinity of the main transformer, x 02 The equivalent parameters of the reactive power compensation capacity of the main transformer. For the near-zone compensation node voltage of the main transformer in the AC substation, Here, δ represents the bus voltage of the main transformer in the AC substation, δ is the power angle of the first unit relative to the second unit, and Q is the reactive power flowing between the near zone of the main transformer and the main transformer in the AC substation. Let α1 and β1 be the current vectors flowing between the near zone of the main transformer and the main transformer in the AC substation. middle The proportionality coefficients, α² and β² are respectively middle The proportionality coefficients, α3 and β3 are respectively middle The proportionality coefficient.

[0032] Optionally, the direction of reactive power flow is determined based on pre-set criteria and reactive power electrical quantities, including:

[0033] If the reactive power electrical quantity is greater than the preset threshold, it is determined that the reactive power flows from the near zone of the main transformer to the main transformer in the AC substation.

[0034] If the reactive power electrical quantity is less than the preset threshold, it is determined that the reactive power flows from the main transformer of the AC substation to the near zone of the main transformer.

[0035] If the reactive power electrical quantity is equal to a preset threshold, it is determined that there is no reactive power flow.

[0036] Optionally, when reactive power flows from the near zone of the main transformer to the main transformer in an AC substation, an adjustment scheme for the reactive power compensation strategy is determined, including:

[0037] Based on the preset maximum operating voltage threshold, determine whether the overvoltage of the main transformer near-zone compensation node voltage and the main transformer compensation node voltage of the AC substation exceeds the limit.

[0038] If either the voltage of the main transformer near the compensation node or the voltage of the main transformer compensation node in the AC substation exceeds the overvoltage limit, determine whether there is a margin in the reactive power compensation resources near the main transformer. If there is no margin in the reactive power resources, select to add reactors / turn off capacitors on the low-voltage side of the main transformer, restore the reactive power compensation strategy of the main transformer near the AC substation, recalculate the voltage of the main transformer near the compensation node, the voltage of the main transformer compensation node, and the reactive power exchange, and iterate the above steps.

[0039] If there is a margin in the reactive power compensation resources near the main transformer of the AC substation, select to put in the reactor or turn off the capacitor in the near area of ​​the main transformer, recalculate the voltage of the compensation node in the near area of ​​the main transformer of the AC substation and the voltage of the compensation node of the main transformer of the AC substation, and determine whether it exceeds the limit. If either the voltage of the compensation node in the near area of ​​the main transformer of the AC substation or the overvoltage of the compensation node of the main transformer of the AC substation exceeds the limit, iterate the above steps.

[0040] If neither the voltage of the main transformer near the compensation node nor the overvoltage of the main transformer compensation node exceeds the limit, the system determines whether the voltage of the main transformer near the compensation node nor the low voltage of the main transformer compensation node exceeds the limit based on the preset minimum voltage operating threshold. If either the voltage of the main transformer near the compensation node or the low voltage of the main transformer compensation node exceeds the limit, the system selects to switch on the capacitor / turn off the reactor on the low voltage side of the main transformer, restores the reactive power compensation strategy of the main transformer near the AC substation, recalculates the voltage of the main transformer near the compensation node, the voltage of the main transformer compensation node, and the reactive power exchange, and iterates the above steps.

[0041] If the voltage of the main transformer near the compensation node and the low voltage of the main transformer compensation node in the AC substation are both within limits, the reactive power exchange between the main transformer and the main transformer near the compensation node in the AC substation is determined according to the pre-set upper limit threshold of reactive power exchange. If the reactive power exchange is within limits, the reactive power compensation strategy is adjusted.

[0042] If the reactive power exchange exceeds the limit, iterate the above steps to determine whether there is a margin in the reactive power compensation resources near the main transformer of the AC substation, until the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power exchange all meet the requirements, and the reactive power compensation strategy is adjusted.

[0043] Optionally, the operation of determining whether the overvoltage of the voltage at the near-zone compensation node of the AC substation main transformer and the voltage at the compensation node of the AC substation main transformer has exceeded the limit, based on a pre-set maximum voltage operating threshold, further includes:

[0044] If neither the voltage of the main transformer near the compensation node of the AC substation nor the overvoltage of the main transformer compensation node of the AC substation exceeds the limit, the reactive power exchange between the main transformer and the main transformer near the main transformer is judged according to the pre-set upper limit threshold of reactive power exchange. If the reactive power exchange does not exceed the limit, the strategy adjustment is completed.

[0045] When the reactive power exchange exceeds the limit, determine whether there is a margin in the reactive power compensation resources near the main transformer of the AC substation. If there is no margin in the reactive power resources, choose to put capacitors on the low-voltage side of the main transformer / turn off reactors, restore the reactive power compensation strategy near the main transformer of the AC substation, recalculate the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power exchange, and iterate the above steps.

[0046] If there is a margin in the reactive power compensation resources in the vicinity of the main transformer of the AC substation, select to put in the reactor or turn off the capacitor in the vicinity of the main transformer, recalculate the reactive power exchange, and determine whether it exceeds the limit. If the reactive power exchange exceeds the limit, iterate the above steps.

[0047] If the reactive power exchange amount does not exceed the limit, determine whether the voltage of the AC substation main transformer near-zone compensation node and the low voltage of the AC substation main transformer compensation node exceed the limit. If either the voltage of the AC substation main transformer near-zone compensation node or the low voltage of the AC substation main transformer compensation node exceeds the limit, select to put on the capacitor / turn off the reactor on the low voltage side of the main transformer, restore the AC substation main transformer near-zone reactive power compensation strategy, recalculate the voltage of the AC substation main transformer near-zone compensation node, the AC substation main transformer compensation node voltage and reactive power exchange amount, and iterate the above steps.

[0048] The reactive power compensation strategy is adjusted when neither the voltage of the near-zone compensation node of the main transformer in the AC substation nor the low voltage of the compensation node of the main transformer in the AC substation exceeds the limit.

[0049] Optionally, when reactive power flows from the main transformer of the AC substation to the near zone of the main transformer, an adjustment scheme for the reactive power compensation strategy is determined based on the direction of reactive power flow, including:

[0050] Based on the preset maximum operating voltage threshold, determine whether the overvoltage of the main transformer near-zone compensation node voltage and the main transformer compensation node voltage of the AC substation exceeds the limit.

[0051] If either the voltage of the main transformer near the compensation node or the voltage of the main transformer compensation node in the AC substation exceeds the overvoltage limit, determine whether there is a margin in the reactive power compensation resources near the main transformer. If there is no margin in the reactive power resources, select to add reactors / turn off capacitors on the low-voltage side of the main transformer, restore the reactive power compensation strategy of the main transformer near the AC substation, recalculate the voltage of the main transformer near the compensation node, the voltage of the main transformer compensation node, and the reactive power exchange, and iterate the above steps.

[0052] If there is a margin in the reactive power compensation resources near the main transformer of the AC substation, select to put in the reactor or turn off the capacitor in the near area of ​​the main transformer, recalculate the voltage of the compensation node in the near area of ​​the main transformer of the AC substation and the voltage of the compensation node of the main transformer of the AC substation, and determine whether it exceeds the limit. If either the voltage of the compensation node in the near area of ​​the main transformer of the AC substation or the overvoltage of the compensation node of the main transformer of the AC substation exceeds the limit, iterate the above steps.

[0053] If neither the voltage of the main transformer near the compensation node nor the overvoltage of the main transformer compensation node exceeds the limit, the system determines whether the voltage of the main transformer near the compensation node nor the low voltage of the main transformer compensation node exceeds the limit based on the preset minimum voltage operating threshold. If either the voltage of the main transformer near the compensation node or the low voltage of the main transformer compensation node exceeds the limit, the system selects to switch on the capacitor / turn off the reactor on the low voltage side of the main transformer, restores the reactive power compensation strategy of the main transformer near the AC substation, recalculates the voltage of the main transformer near the compensation node, the voltage of the main transformer compensation node, and the reactive power exchange, and iterates the above steps.

[0054] If the voltage of the main transformer near the compensation node and the low voltage of the main transformer compensation node in the AC substation are both within limits, the reactive power exchange between the main transformer and the main transformer near the compensation node in the AC substation is determined according to the pre-set upper limit threshold of reactive power exchange. If the reactive power exchange is within limits, the reactive power compensation strategy is adjusted.

[0055] When the reactive power exchange exceeds the limit, the reactor is switched on / the capacitor is switched off on the low-voltage side of the main transformer to restore the reactive power compensation strategy of the AC substation main transformer near zone. The voltage of the AC substation main transformer near zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power exchange are recalculated. The above steps are iterated until the voltage of the AC substation main transformer near zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power exchange all meet the requirements, and the reactive power compensation strategy adjustment is completed.

[0056] Optionally, based on a pre-set maximum operating voltage threshold, it is determined whether the overvoltage of the near-zone compensation node voltage of the AC substation main transformer and the compensation node voltage of the AC substation main transformer have exceeded the limit, including:

[0057] If neither the voltage of the main transformer near the compensation node of the AC substation nor the overvoltage of the main transformer compensation node of the AC substation exceeds the limit, the reactive power exchange between the main transformer and the main transformer near the main transformer is judged according to the pre-set upper limit threshold of reactive power exchange. If the reactive power exchange does not exceed the limit, the strategy adjustment is completed.

[0058] When the reactive power exchange exceeds the limit, determine whether there is a margin in the reactive power compensation resources near the main transformer of the AC substation. If there is no margin in the reactive power resources, choose to put in the reactor / turn off the capacitor on the low voltage side of the main transformer, restore the reactive power compensation strategy near the main transformer of the AC substation, recalculate the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power exchange, and iterate the above steps.

[0059] If there is a margin in the reactive power compensation resources near the main transformer of the AC substation, select to put on capacitors / turn off reactors in the near area of ​​the main transformer, recalculate the reactive power exchange, and determine whether it exceeds the limit. If the reactive power exchange exceeds the limit, iterate the above steps.

[0060] If the reactive power exchange amount does not exceed the limit, determine whether the voltage of the AC substation main transformer near-zone compensation node and the overvoltage of the AC substation main transformer compensation node exceed the limit. If either the voltage of the AC substation main transformer near-zone compensation node or the voltage of the AC substation main transformer compensation node exceeds the limit, select to put in the reactor / turn off the capacitor on the low-voltage side of the main transformer, restore the AC substation main transformer near-zone reactive power compensation strategy, recalculate the voltage of the AC substation main transformer near-zone compensation node, the voltage of the AC substation main transformer compensation node and the reactive power exchange amount, and iterate the above steps.

[0061] The reactive power compensation strategy is adjusted when neither the voltage of the near-zone compensation node of the main transformer in the AC substation nor the low voltage of the compensation node of the main transformer in the AC substation exceeds the limit.

[0062] According to another aspect of the present invention, a real-time adjustment device for overvoltage and reactive power compensation strategies in AC substations is provided, comprising:

[0063] The acquisition module is used to acquire, in real time, the equivalent electrical quantity parameters of the first unit connected to the AC substation and the equivalent electrical quantity parameters of the second unit, based on the equivalent model of the interconnected system.

[0064] The output module is used to utilize the equivalent model of the interconnected system to output the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power electrical quantity flowing between the main transformer near the main transformer and the main transformer, based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit.

[0065] The first determining module is used to determine the direction of reactive power flow based on pre-set criteria and reactive power electrical quantities.

[0066] The second determining module is used to determine the adjustment scheme of the reactive power compensation strategy based on the direction of reactive power flow.

[0067] According to another aspect of the present invention, a computer-readable storage medium is provided, the storage medium storing a computer program for performing the methods described in any of the above aspects of the present invention.

[0068] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: a processor; a memory for storing executable instructions of the processor; the processor being configured to read the executable instructions from the memory and execute the instructions to implement the method described in any of the preceding aspects of the present invention.

[0069] Therefore, this invention patent proposes a real-time adjustment method for overvoltage and reactive power compensation strategies in AC substations. It only requires real-time acquisition of the system equivalent parameters during AC substation overvoltage operation to automatically complete the adjustment of overvoltage and reactive power strategies for the main transformer and nearby areas. The adjustment process is logically clear, simple, and easy to implement, helping to improve the efficiency of safety analysis in actual power grid operation. Attached Figure Description

[0070] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0071] Figure 1 This is a flowchart illustrating a real-time adjustment method for overvoltage and reactive power compensation strategies in AC substations provided by an exemplary embodiment of the present invention.

[0072] Figure 2 This is an equivalent diagram of an interconnected system provided in an exemplary embodiment of the present invention;

[0073] Figure 3 This is an isomorphic diagram of the system after star-angle transformation provided in an exemplary embodiment of the present invention;

[0074] Figure 4 This is another flowchart illustrating a real-time adjustment method for overvoltage and reactive power compensation strategies in AC substations provided in an exemplary embodiment of the present invention.

[0075] Figure 5This is a schematic diagram of the structure of a real-time adjustment device for overvoltage and reactive power compensation strategies in AC substations provided in an exemplary embodiment of the present invention.

[0076] Figure 6 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. Detailed Implementation

[0077] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0078] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0079] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of the present invention are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0080] It should also be understood that in the embodiments of the present invention, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0081] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more unless explicitly defined or given contrary instructions in the context.

[0082] Furthermore, the term "and / or" in this invention is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this invention generally indicates that the preceding and following related objects have an "or" relationship.

[0083] It should also be understood that the description of the various embodiments in this invention emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0084] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0085] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0086] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0087] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0088] The embodiments of this invention can be applied to electronic devices such as terminal devices, computer systems, and servers, and can operate together with a wide range of other general-purpose or special-purpose computing system environments or configurations. Well-known examples of terminal devices, computing systems, environments, and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, and servers include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments including any of the above systems, etc.

[0089] Electronic devices such as terminal devices, computer systems, and servers can be described in the general context of computer system executable instructions (such as program modules) executed by a computer system. Typically, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in distributed cloud computing environments, where tasks are executed by remote processing devices linked through communication networks. In distributed cloud computing environments, program modules can reside on local or remote computing system storage media, including storage devices.

[0090] Exemplary methods

[0091] Figure 1 This is a flowchart illustrating a real-time adjustment method for overvoltage and reactive power compensation strategies in AC substations, provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as... Figure 1 As shown, the real-time adjustment method 100 for overvoltage and reactive power compensation strategies in AC substations includes the following steps:

[0092] Step 101: Based on the equivalent model of the interconnected system, obtain in real time the equivalent electrical quantity parameters of the first unit connected to the AC substation and the equivalent electrical quantity parameters of the second unit.

[0093] Step 102: Using the equivalent model of the interconnected system, based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit, output the voltage of the compensation node of the AC substation main transformer near the main transformer, the voltage of the compensation node of the AC substation main transformer, and the reactive power electrical quantity flowing between the AC substation main transformer near the main transformer and the main transformer.

[0094] Step 103: Determine the direction of reactive power flow based on the pre-set criteria and reactive power electrical quantities;

[0095] Step 104: Determine the adjustment scheme of the reactive power compensation strategy based on the direction of reactive power flow.

[0096] Specifically, the present invention is accomplished through the following technical solution:

[0097] Step 1: Real-time acquisition of system equivalent parameters, reactive power compensation strategy for AC substations, and reasonable operating range.

[0098] (1) Real-time acquisition of equivalent parameters of the system and reactive power compensation strategies of AC substation main transformer and its vicinity.

[0099] Isographs of interconnected systems Figure 2 As shown, before calculation, it is necessary to obtain in real time the equivalent electromotive force E1, equivalent reactance x1 of the first unit, the equivalent electromotive force E2, equivalent reactance x2 of the second unit, the active power P transmitted between the two systems, the electrical distance x0 between the main transformer and the near-zone of the main transformer in the AC substation, and the equivalent parameters x of the reactive power compensation capacity near the main transformer. 01 The equivalent parameter x of the reactive power compensation capacity of the main transformer 02 All of the above parameters are known electrical quantities.

[0100] U in the isomorphic diagram of interconnected systems 01 For the near-zone compensation node voltage of the main transformer in an AC substation, U 02 δ is the bus voltage of the main transformer in the AC substation, δ is the power angle of the first unit relative to the second unit, and Q is the reactive power flowing between the main transformer near the main transformer and the main transformer in the AC substation. All of the above parameters are electrical quantities to be determined.

[0101] (2) Given a reasonable operating range

[0102] Before calculation, the reasonable operating voltage range U of the system under normal operation needs to be given. min U max and the upper limit of reactive power exchange between the main transformer and the near zone of the main transformer in an AC substation, Q max .

[0103] (3) Solve for the electrical quantities of the system based on the known parameters.

[0104] right Figure 2 Two star-angle transformations are performed to obtain the new interconnected system isograph, as shown below. Figure 3 As shown.

[0105] Calculate the direct connection impedance x between the first unit and the second unit according to equation (1):

[0106]

[0107] Calculate the power angle δ according to equation (2):

[0108]

[0109] Calculate the voltage of the near-zone compensation node of the main transformer in the AC substation according to equations (3) to (6).

[0110]

[0111]

[0112]

[0113] Calculate the main transformer compensation node voltage of the AC substation according to equations (7) to (8).

[0114]

[0115]

[0116] Calculate the reactive power exchange Q between the near zone of the main transformer and the main transformer in the AC substation according to equations (9) to (11):

[0117]

[0118]

[0119]

[0120] Where E1 is the equivalent electromotive force of the first unit, Let E1 be the equivalent potential vector form of the first unit, x1 be the equivalent reactance of the first unit, and E2 be the equivalent potential of the second unit. x1 is the equivalent potential vector form of the second unit, x2 is the equivalent reactance of the second unit, P is the active power transmitted between the two systems, x0 is the electrical distance between the main transformer and the adjacent section of the AC substation, and x... 01 Equivalent parameters of reactive power compensation capacity in the vicinity of the main transformer, x 02 The equivalent parameters of the reactive power compensation capacity of the main transformer. For the near-zone compensation node voltage of the main transformer in the AC substation, Here, δ represents the bus voltage of the main transformer in the AC substation, δ is the power angle of the first unit relative to the second unit, and Q is the reactive power flowing between the near zone of the main transformer and the main transformer in the AC substation. Let α1 and β1 be the current vectors flowing between the near zone of the main transformer and the main transformer in the AC substation. middle The proportionality coefficients, α² and β² are respectively middle The proportionality coefficients, α3 and β3 are respectively middle The proportionality coefficient.

[0121] Step 2: Determining the direction of reactive power flow

[0122] The reactive power reference flow direction is from the area near the main transformer of the AC substation to the main transformer. If the reactive power Q>0, that is, the reactive power flows from the area near the main transformer of the AC substation to the main transformer, proceed to step 3; if the reactive power Q<0, that is, the reactive power flows from the main transformer of the AC substation to the area near the main transformer, proceed to step 4.

[0123] Step 3: Reference Figure 4 As shown, the reactive power compensation strategy is adjusted when reactive power flows from the near zone of the main transformer to the main transformer in an AC substation.

[0124] (1) Overvoltage limit judgment between the main transformer bus and the near-zone compensation node of the main transformer in AC substation

[0125] Calculate U according to equations (1) to (11) 01 U 02 Q determines whether the overvoltage exceeds the limit between the main transformer bus and the main transformer near-zone compensation node in the AC substation. If either exceeds the limit, proceed to step 3(2); if neither voltage exceeds the limit, proceed to step 3(6).

[0126] (2) Judgment of reactive power compensation resource margin in the vicinity of main transformer of AC substation

[0127] Determine the reactive power resource margin in the vicinity of the main transformer of the AC substation. If there is still a reactive power resource margin, select to add reactance / turn off capacitor in the vicinity of the main transformer and recalculate U according to equations (1) to (11). 01 U 02 After Q, proceed to step 3(3); if there is no margin in reactive power resources, select to add reactors / turn off capacitors on the low-voltage side of the main transformer, and restore the reactive power compensation strategy of the near-zone of the main transformer in the AC substation, and recalculate U according to equations (1) to (11). 01 U 02 After Q, return to step 3(1).

[0128] (3) Overvoltage limit judgment between the main transformer bus and the near-zone compensation node of the main transformer in AC substation

[0129] Determine the overvoltage limit status of the main transformer bus and the main transformer near-zone compensation node in the AC substation. If either exceeds the limit, return to step 3(2); if neither voltage exceeds the limit, proceed to step 3(4).

[0130] (4) Judgment of low voltage over-limit between main transformer bus and main transformer near-zone compensation node in AC substation

[0131] Determine the low-voltage over-limit situation of the main transformer bus and the near-zone compensation node of the AC substation. If any over-limit situation occurs, select to switch on the capacitor / turn off the reactor on the low-voltage side of the main transformer, and restore the reactive power compensation strategy of the near-zone of the AC substation main transformer. Recalculate U according to equations (1) to (11). 01 U 02 After Q, return to step 3(1); if neither exceeds the limit, proceed to step 3(5).

[0132] (5) Judgment of excessive reactive power exchange between main transformers and near-transformer zones in AC substations

[0133] Determine whether the reactive power exchange |Q| between the main transformer and the near zone of the main transformer in an AC substation exceeds Q. max If the reactive power exchange amount does not exceed the limit, the strategy adjustment is completed; if the reactive power exchange amount exceeds the limit, return to step 3(2), and repeat this cycle until both voltage and reactive power exchange amount meet the requirements, then the strategy adjustment is completed.

[0134] (6) Judgment of excessive reactive power exchange between main transformers and near-transformer zones in AC substations

[0135] Determine whether the reactive power exchange |Q| between the main transformer and the near zone of the main transformer in an AC substation exceeds Q. max If the reactive power exchange amount does not exceed the limit, the strategy adjustment is completed; if the reactive power exchange amount exceeds the limit, proceed to step 3(7).

[0136] (7) Judgment of reactive power compensation resource margin in the vicinity of main transformer of AC substation

[0137] Determine the reactive power resource margin in the vicinity of the main transformer of the AC substation. If there is still a reactive power resource margin, select to add reactance / turn off capacitor in the vicinity of the main transformer and recalculate U according to equations (1) to (11). 01 U 02 After Q, proceed to step 3(8); if there is no margin in reactive power resources, select to switch capacitors / turn off reactors on the low-voltage side of the main transformer, and restore the reactive power compensation strategy of the near-zone of the main transformer in the AC substation, and recalculate U according to equations (1) to (11). 01 U 02 After Q, return to step 3(1).

[0138] (8) Determine whether the reactive power exchange between the main transformer and the near zone of the AC substation, |Q|, exceeds Q. maxIf the reactive power exchange exceeds the limit, return to step 3(7); if the reactive power exchange does not exceed the limit, proceed to step 3(9).

[0139] (9) Judgment of low voltage over-limit between main transformer bus and main transformer near-zone compensation node in AC substation

[0140] Determine the low-voltage over-limit situation of the main transformer bus and the near-zone compensation node of the AC substation. If any over-limit situation occurs, select to switch on the capacitor / turn off the reactor on the low-voltage side of the main transformer, and restore the reactive power compensation strategy of the near-zone of the AC substation main transformer. Recalculate U according to equations (1) to (11). 01 U 02 After Q, return to step 3(1); if neither voltage exceeds the limit, the strategy adjustment is completed.

[0141] Step 4: Reference Figure 4 As shown, the reactive power compensation strategy is adjusted when reactive power flows from the main transformer of the AC substation to the near zone of the main transformer.

[0142] (1) Overvoltage limit judgment between the main transformer bus and the near-zone compensation node of the main transformer in AC substation

[0143] Calculate U according to equations (1) to (11) 01 U 02 Q determines whether the overvoltage exceeds the limit of the main transformer bus and the main transformer near-zone compensation node in the AC substation. If either exceeds the limit, proceed to step 4(2); if neither voltage exceeds the limit, proceed to step 4(6).

[0144] (2) Judgment of reactive power compensation resource margin in the vicinity of main transformer of AC substation

[0145] Determine the reactive power resource margin in the vicinity of the main transformer of the AC substation. If there is still a reactive power resource margin, select to add reactance / turn off capacitor in the vicinity of the main transformer and recalculate U according to equations (1) to (11). 01 U 02 After Q, proceed to step 4(3); if there is no margin in reactive power resources, select to add reactors / turn off capacitors on the low-voltage side of the main transformer, and restore the reactive power compensation strategy of the near-zone of the main transformer in the AC substation, and recalculate U according to equations (1) to (11). 01 U 02 After Q, return to step 4(1).

[0146] (3) Overvoltage limit judgment between the main transformer bus and the near-zone compensation node of the main transformer in AC substation

[0147] Determine the overvoltage limit status of the main transformer bus and the main transformer near-zone compensation node in the AC substation. If either exceeds the limit, return to step 4(2); if neither voltage exceeds the limit, proceed to step 4(4).

[0148] (4) Judgment of low voltage over-limit between main transformer bus and main transformer near-zone compensation node in AC substation

[0149] Determine the low-voltage over-limit situation of the main transformer bus and the near-zone compensation node of the AC substation. If any over-limit situation occurs, select to switch on the capacitor / turn off the reactor on the low-voltage side of the main transformer, and restore the reactive power compensation strategy of the near-zone of the AC substation main transformer. Recalculate U according to equations (1) to (11). 01 U 02 After Q, return to step 4(1); if neither exceeds the limit, proceed to step 4(5).

[0150] (5) Judgment of excessive reactive power exchange between main transformers and near-transformer zones in AC substations

[0151] Determine whether the reactive power exchange between the near zone of the main transformer and the main transformer in an AC substation, |Q|, exceeds Q. max If the reactive power exchange amount does not exceed the limit, the strategy adjustment is completed; if the reactive power exchange amount exceeds the limit, select to add reactors / turn off capacitors on the low-voltage side of the main transformer, and restore the reactive power compensation strategy of the near-zone of the AC substation main transformer, and recalculate U according to equations (1) to (11). 01 U 02 After Q, return to step 4(1), and repeat this cycle until the voltage and reactive power exchange quantities both meet the requirements, then the strategy adjustment is complete.

[0152] (6) Judgment of excessive reactive power exchange between main transformers and near-transformer zones in AC substations

[0153] Determine whether the reactive power exchange |Q| between the main transformer and the near zone of the main transformer in an AC substation exceeds Q. max If the reactive power exchange amount does not exceed the limit, the strategy adjustment is completed; if the reactive power exchange amount exceeds the limit, proceed to step 4(7).

[0154] (7) Judgment of reactive power compensation resource margin in the vicinity of main transformer of AC substation

[0155] Determine the reactive power resource margin in the vicinity of the main transformer of the AC substation. If there is still a reactive power resource margin, select to add capacitors / turn off reactors in the vicinity of the main transformer and recalculate U according to equations (1) to (11). 01 U 02 After Q, proceed to step 4(8); if there is no margin in reactive power resources, select to add reactors / turn off capacitors on the low-voltage side of the main transformer, and restore the reactive power compensation strategy of the near-zone of the main transformer in the AC substation, and recalculate U according to equations (1) to (11). 01 U 02 After Q, return to step 4(1).

[0156] (8) Judgment of excessive reactive power exchange between main transformers and near-transformer zones in AC substations

[0157] Determine whether the reactive power exchange |Q| between the main transformer and the near zone of the main transformer in an AC substation exceeds Q. maxIf the reactive power exchange exceeds the limit, return to step 4(7); if the reactive power exchange does not exceed the limit, proceed to step 4(9).

[0158] (9) Overvoltage limit judgment between the main transformer bus and the near-zone compensation node of the main transformer in AC substation

[0159] Determine the overvoltage limit situation of the main transformer bus and the near-zone compensation node of the AC substation. If any limit is exceeded, select to switch on the reactor / off the capacitor on the low-voltage side of the main transformer and restore the reactive power compensation strategy of the near-zone of the AC substation main transformer. Recalculate U according to equations (1) to (11). 01 U 02 After Q, return to step 3(1); if neither voltage exceeds the limit, the strategy adjustment is completed.

[0160] Once all the above calculations are completed and the requirements are met, the real-time adjustment of the overvoltage and reactive power compensation strategies for the main transformer and its near-zone in the AC substation is completed.

[0161] Therefore, this invention patent proposes a real-time adjustment method for overvoltage and reactive power compensation strategies in AC substations. It only requires real-time acquisition of the system equivalent parameters during AC substation overvoltage operation to automatically complete the adjustment of overvoltage and reactive power strategies for the main transformer and near-zone. The adjustment process is logically clear, simple and easy to implement, which helps to improve the efficiency of safety analysis in actual power grid operation.

[0162] Exemplary device

[0163] Figure 5 This is a schematic diagram of the structure of a real-time adjustment device for overvoltage and reactive power compensation strategies in AC substations, provided in an exemplary embodiment of the present invention. Figure 5 As shown, the device 500 includes:

[0164] The acquisition module 510 is used to acquire, in real time, the equivalent electrical quantity parameters of the first unit connected to the AC substation and the equivalent electrical quantity parameters of the second unit based on the equivalent model of the interconnected system.

[0165] Output module 520 is used to output the voltage of the AC substation main transformer near-zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power electrical quantity flowing between the AC substation main transformer near zone and the main transformer, based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit using the equivalent model of the interconnected system.

[0166] The first determining module 530 is used to determine the direction of reactive power flow based on pre-set criteria and reactive power electrical quantities.

[0167] The second determining module 540 is used to determine the adjustment scheme of the reactive power compensation strategy based on the direction of reactive power flow.

[0168] Optionally, the output module 520 includes:

[0169] The calculation submodule is used to calculate the voltage of the near-zone compensation node of the AC substation main transformer, the voltage of the compensation node of the AC substation main transformer, and the power angle of the first unit relative to the second unit based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit.

[0170] Based on the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the power angle of the first unit relative to the second unit, calculate the reactive power electrical quantity flowing between the main transformer near the AC substation and the main transformer.

[0171] Optionally, using the equivalent model of the interconnected system, based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit, the calculation formulas for the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power electrical quantity flowing between the near zone of the main transformer and the main transformer of the AC substation are as follows:

[0172] Calculate the direct connection impedance x between the first unit and the second unit according to equation (1):

[0173]

[0174] Calculate the power angle δ according to equation (2):

[0175]

[0176] Calculate the voltage of the near-zone compensation node of the main transformer in the AC substation according to equations (3) to (6).

[0177]

[0178]

[0179]

[0180] Calculate the main transformer compensation node voltage of the AC substation according to equations (7) to (8).

[0181]

[0182]

[0183] Calculate the reactive power exchange Q between the near zone of the main transformer and the main transformer in the AC substation according to equations (9) to (11):

[0184]

[0185]

[0186]

[0187] Where E1 is the equivalent electromotive force of the first unit, Let E1 be the equivalent potential vector form of the first unit, x1 be the equivalent reactance of the first unit, and E2 be the equivalent potential of the second unit. x1 is the equivalent potential vector form of the second unit, x2 is the equivalent reactance of the second unit, P is the active power transmitted between the two systems, x0 is the electrical distance between the main transformer and the adjacent section of the AC substation, and x... 01 Equivalent parameters of reactive power compensation capacity in the vicinity of the main transformer, x 02 The equivalent parameters of the reactive power compensation capacity of the main transformer. For the near-zone compensation node voltage of the main transformer in the AC substation, Here, δ represents the bus voltage of the main transformer in the AC substation, δ is the power angle of the first unit relative to the second unit, and Q is the reactive power flowing between the near zone of the main transformer and the main transformer in the AC substation. Let α1 and β1 be the current vectors flowing between the near zone of the main transformer and the main transformer in the AC substation. middle The proportionality coefficients, α² and β² are respectively middle The proportionality coefficients, α3 and β3 are respectively middle The proportionality coefficient.

[0188] Optionally, the first determining module 530 includes:

[0189] The first determination submodule is used to determine that reactive power flows from the near zone of the main transformer to the main transformer when the reactive power electrical quantity is greater than a preset threshold.

[0190] The second determination submodule is used to determine that reactive power flows from the main transformer of the AC substation to the near zone of the main transformer when the reactive power electrical quantity is less than a preset threshold.

[0191] The third determination submodule is used to determine that there is no reactive power flow when the reactive power electrical quantity is equal to a preset threshold.

[0192] Optionally, when reactive power flows from the near zone of the main transformer to the main transformer in an AC substation, the second determining module 540 includes:

[0193] The first judgment submodule is used to determine whether the overvoltage of the main transformer near the compensation node voltage and the main transformer compensation node voltage of the AC substation exceeds the limit based on the preset maximum voltage operating threshold.

[0194] The second judgment submodule is used to determine whether there is a margin in the reactive power compensation resources of the AC substation main transformer near the compensation node and the AC substation main transformer compensation node voltage when either voltage exceeds the limit. If there is no margin in reactive power resources, the module selects to put in a reactor / turn off a capacitor on the low voltage side of the main transformer, restores the AC substation main transformer near the reactive power compensation strategy, recalculates the voltage of the AC substation main transformer near the compensation node, the AC substation main transformer compensation node voltage and reactive power exchange, and iterates the above steps.

[0195] The third judgment submodule is used to select to put on reactors or turn off capacitors in the near zone of the main transformer when there is a margin in the reactive power compensation resources of the main transformer of the AC substation, recalculate the voltage of the compensation node in the near zone of the main transformer of the AC substation and the voltage of the compensation node of the main transformer of the AC substation, and determine whether the limit is exceeded. If the voltage of the compensation node in the near zone of the main transformer of the AC substation and the overvoltage of the compensation node of the main transformer of the AC substation exceed the limit, the above steps are iterated.

[0196] The fourth judgment submodule is used to determine whether the voltage of the AC substation main transformer near-zone compensation node and the overvoltage of the AC substation main transformer compensation node exceed the limit, based on the preset minimum voltage operating threshold. If either the voltage of the AC substation main transformer near-zone compensation node or the low voltage of the AC substation main transformer compensation node exceeds the limit, the module will switch to capacitors / turn off reactors on the low-voltage side of the main transformer, restore the reactive power compensation strategy of the AC substation main transformer near-zone, recalculate the voltage of the AC substation main transformer near-zone compensation node, the voltage of the AC substation main transformer compensation node and the reactive power exchange, and iterate the above steps.

[0197] The fifth judgment submodule is used to determine whether the reactive power exchange between the main transformer and the main transformer near the main transformer exceeds the limit, provided that neither the voltage of the main transformer near the main transformer compensation node nor the low voltage of the main transformer compensation node in the AC substation exceeds the limit, based on the pre-set upper limit threshold of reactive power exchange. If the reactive power exchange does not exceed the limit, the reactive power compensation strategy is adjusted.

[0198] The first completion submodule is used to iterate the above steps when the reactive power exchange exceeds the limit, to determine whether there is a margin in the reactive power compensation resources near the main transformer of the AC substation, until the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power exchange all meet the requirements, and to complete the adjustment of the reactive power compensation strategy.

[0199] Optionally, the first judgment submodule also includes:

[0200] The first judgment unit is used to determine whether the reactive power exchange between the main transformer and the main transformer near the main transformer exceeds the limit, based on the pre-set upper limit threshold of reactive power exchange, when the voltage of the main transformer near the main transformer and the overvoltage of the main transformer compensation node of the AC substation are both within the limit. If the reactive power exchange does not exceed the limit, the strategy adjustment is completed.

[0201] The second judgment unit is used to determine whether there is a margin in the reactive power compensation resources near the main transformer of the AC substation when the reactive power exchange exceeds the limit. If there is no margin in the reactive power resources, it selects to put capacitors on / turn off reactors on the low voltage side of the main transformer, restores the reactive power compensation strategy near the main transformer of the AC substation, recalculates the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power exchange, and iterates the above steps.

[0202] The third judgment unit is used to select to put on a reactor or turn off a capacitor in the near zone of the main transformer when there is a margin in the reactive power compensation resources of the main transformer of the AC substation, recalculate the reactive power exchange, and determine whether it exceeds the limit. If the reactive power exchange exceeds the limit, the above steps are iterated.

[0203] The fourth judgment unit is used to determine whether the voltage of the near-zone compensation node of the AC substation main transformer and the low voltage of the AC substation main transformer compensation node exceed the limit when the reactive power exchange amount does not exceed the limit. If either the voltage of the near-zone compensation node of the AC substation main transformer or the low voltage of the AC substation main transformer compensation node exceeds the limit, the unit selects to put on the capacitor / turn off the reactor on the low voltage side of the main transformer, restores the reactive power compensation strategy of the near-zone of the AC substation main transformer, recalculates the voltage of the near-zone compensation node of the AC substation main transformer, the voltage of the AC substation main transformer compensation node and the reactive power exchange amount, and iterates the above steps.

[0204] The first completion unit is used to adjust the reactive power compensation strategy when the voltage of the near-zone compensation node of the main transformer in the AC substation and the low voltage of the compensation node of the main transformer in the AC substation are both within the limits.

[0205] Optionally, when reactive power flows from the main transformer of the AC substation to the near zone of the main transformer, the second determining module 540, based on the direction of reactive power flow, includes:

[0206] Based on the preset maximum operating voltage threshold, determine whether the overvoltage of the main transformer near-zone compensation node voltage and the main transformer compensation node voltage of the AC substation exceeds the limit.

[0207] The sixth judgment submodule is used to determine whether there is a margin in the reactive power compensation resources of the AC substation main transformer near the compensation node and the AC substation main transformer compensation node voltage when either voltage exceeds the limit. If there is no margin in reactive power resources, the module selects to put on a reactor / turn off a capacitor on the low voltage side of the main transformer, restores the AC substation main transformer near the reactive power compensation strategy, recalculates the voltage of the AC substation main transformer near the compensation node, the AC substation main transformer compensation node voltage and reactive power exchange, and iterates the above steps.

[0208] The seventh judgment submodule is used to select to put on reactors or turn off capacitors in the near zone of the main transformer of the AC substation when there is a margin in the reactive power compensation resources in the near zone of the main transformer, recalculate the voltage of the compensation node in the near zone of the main transformer of the AC substation and the voltage of the compensation node of the main transformer of the AC substation, and determine whether the limit is exceeded. If the voltage of the compensation node in the near zone of the main transformer of the AC substation and the overvoltage of the compensation node of the main transformer of the AC substation exceed the limit, the above steps are iterated.

[0209] The eighth judgment submodule is used to determine whether the voltage of the AC substation main transformer near-zone compensation node and the overvoltage of the AC substation main transformer compensation node exceed the limit, based on the preset minimum voltage operating threshold. If either the voltage of the AC substation main transformer near-zone compensation node or the voltage of the AC substation main transformer compensation node exceeds the limit, the module will select to switch on the capacitor / turn off the reactor on the low-voltage side of the main transformer, restore the AC substation main transformer near-zone reactive power compensation strategy, recalculate the voltage of the AC substation main transformer near-zone compensation node, the voltage of the AC substation main transformer compensation node and the reactive power exchange, and iterate the above steps.

[0210] The ninth judgment submodule is used to determine whether the reactive power exchange between the main transformer and the main transformer near the main transformer exceeds the limit, provided that neither the voltage of the main transformer near the main transformer compensation node nor the low voltage of the main transformer compensation node in the AC substation exceeds the limit, based on the pre-set upper limit threshold of reactive power exchange. If the reactive power exchange does not exceed the limit, the reactive power compensation strategy is adjusted.

[0211] The second completion submodule is used to select to add reactors / turn off capacitors on the low-voltage side of the main transformer when the reactive power exchange exceeds the limit, restore the reactive power compensation strategy of the AC substation main transformer near zone, recalculate the voltage of the AC substation main transformer near zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power exchange, and iterate the above steps until the voltage of the AC substation main transformer near zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power exchange all meet the requirements, thus completing the adjustment of the reactive power compensation strategy.

[0212] Optionally, the sixth judgment submodule includes:

[0213] The fifth judgment unit is used to determine whether the reactive power exchange between the main transformer and the main transformer near the main transformer exceeds the limit, based on the pre-set upper limit threshold of reactive power exchange, when the voltage of the main transformer near the main transformer and the overvoltage of the main transformer compensation node in the AC substation are both within the limit. If the reactive power exchange does not exceed the limit, the strategy adjustment is completed.

[0214] The sixth judgment unit is used to determine whether there is a margin in the reactive power compensation resources near the main transformer of the AC substation when the reactive power exchange exceeds the limit. If there is no margin in the reactive power resources, it selects to put on the reactor / turn off the capacitor on the low voltage side of the main transformer, restores the reactive power compensation strategy near the main transformer of the AC substation, recalculates the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power exchange, and iterates the above steps.

[0215] The seventh judgment unit is used to select the energized capacitor / deactivated reactor in the near zone of the main transformer of the AC substation when there is a margin in the reactive power compensation resources, recalculate the reactive power exchange, and determine whether it exceeds the limit. If the reactive power exchange exceeds the limit, the above steps are iterated.

[0216] The eighth judgment unit is used to determine whether the voltage of the near-zone compensation node of the AC substation main transformer and the overvoltage of the AC substation main transformer compensation node exceed the limit when the reactive power exchange amount does not exceed the limit. If either the voltage of the near-zone compensation node of the AC substation main transformer or the overvoltage of the AC substation main transformer compensation node exceeds the limit, the unit selects to put the reactor on / turn off the capacitor on the low-voltage side of the main transformer, restores the reactive power compensation strategy of the near-zone of the AC substation main transformer, recalculates the voltage of the near-zone compensation node of the AC substation main transformer, the voltage of the AC substation main transformer compensation node and the reactive power exchange amount, and iterates the above steps.

[0217] The second completion unit is used to adjust the reactive power compensation strategy when the voltage of the near-zone compensation node of the main transformer in the AC substation and the low voltage of the compensation node of the main transformer in the AC substation are both within the limits.

[0218] Exemplary electronic devices

[0219] Figure 6 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. For example... Figure 6 As shown, the electronic device 60 includes one or more processors 61 and a memory 62.

[0220] The processor 61 may be a central processing unit (CPU) or other form of processing unit with data processing and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0221] The memory 62 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 61 may execute the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above, and / or other desired functions. In one example, the electronic device may also include an input device 63 and an output device 64, these components being interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0222] In addition, the input device 63 may also include, for example, a keyboard, a mouse, etc.

[0223] The output device 64 can output various information to the outside. The output device 64 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0224] Of course, for the sake of simplicity, Figure 6 Only some of the components of this electronic device relevant to the present invention are shown, omitting components such as buses, input / output interfaces, etc. In addition, the electronic device may include any other suitable components depending on the specific application.

[0225] Exemplary computer program products and computer-readable storage media

[0226] In addition to the methods and apparatus described above, embodiments of the present invention may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0227] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of the present invention. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0228] Furthermore, embodiments of the present invention may also be computer-readable storage media storing computer program instructions thereon, which, when executed by a processor, cause the processor to perform the steps of the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0229] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0230] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0231] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0232] The block diagrams of devices, systems, devices, and systems involved in this invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, systems, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0233] The methods and systems of the present invention may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of the present invention are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, the present invention may also be implemented as a program recorded on a recording medium, the program comprising machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers recording media storing programs for performing the methods according to the present invention.

[0234] It should also be noted that in the systems, apparatus, and methods of the present invention, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered equivalents of the present invention. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0235] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A real-time adjustment method for overvoltage and reactive power compensation strategies in AC substations, characterized in that, include: Based on the equivalent model of the interconnected system, the equivalent electrical quantity parameters of the first unit connected to the AC substation and the equivalent electrical quantity parameters of the second unit are obtained in real time. Using the equivalent model of the interconnected system, based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit, the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power electrical quantity flowing between the near zone of the main transformer and the main transformer of the AC substation are output. The direction of reactive power flow is determined based on the pre-set criteria and the reactive power electrical quantity. Based on the direction of the reactive power flow, determine the adjustment scheme of the reactive power compensation strategy; When the reactive power quantity exceeds a preset threshold, it is determined that the reactive power flows from the near zone of the AC substation main transformer to the main transformer. When the reactive power flows from the near zone of the AC substation main transformer to the main transformer, an adjustment scheme for the reactive power compensation strategy is determined, including: Based on the preset maximum operating voltage threshold, determine whether the voltage of the near-zone compensation node of the AC substation main transformer and the voltage of the compensation node of the AC substation main transformer are over-voltage or exceed the limit. If either the voltage of the main transformer near the compensation node of the AC substation or the voltage of the main transformer compensation node of the AC substation exceeds the overvoltage limit, determine whether there is a margin in the reactive power compensation resources of the main transformer near the AC substation. If there is no margin in the reactive power compensation resources, select to add reactors / turn off capacitors on the low-voltage side of the main transformer, restore the reactive power compensation strategy of the main transformer near the AC substation, recalculate the voltage of the main transformer near the compensation node of the AC substation, the voltage of the main transformer compensation node of the AC substation, and the reactive power exchange between the main transformer near the AC substation and the main transformer, and iterate the above steps. If there is a margin in the reactive power compensation resources near the main transformer of the AC substation, select to add reactors or turn off capacitors in the near area of ​​the main transformer, recalculate the voltage of the compensation node in the near area of ​​the main transformer of the AC substation and the voltage of the compensation node of the main transformer of the AC substation, and determine whether the limit is exceeded. If either the voltage of the compensation node in the near area of ​​the main transformer of the AC substation or the voltage of the compensation node of the main transformer of the AC substation exceeds the overvoltage limit, iterate the above steps. If neither the voltage of the near-zone compensation node of the AC substation main transformer nor the voltage of the AC substation main transformer compensation node exceeds the voltage limit, based on the preset minimum voltage operating threshold, it is determined whether the voltage of the near-zone compensation node of the AC substation main transformer nor the voltage of the AC substation main transformer compensation node exceeds the low voltage limit. If either the voltage of the near-zone compensation node of the AC substation main transformer or the voltage of the AC substation main transformer compensation node exceeds the low voltage limit, a capacitor is switched on / a reactor is switched off on the low-voltage side of the main transformer, the reactive power compensation strategy of the near-zone compensation node of the AC substation main transformer is restored, the voltage of the near-zone compensation node of the AC substation main transformer, the voltage of the AC substation main transformer compensation node, and the reactive power exchange are recalculated, and the above steps are iterated. If neither the voltage of the near-zone compensation node of the AC substation main transformer nor the voltage of the AC substation main transformer compensation node exceeds the low voltage limit, the reactive power exchange between the AC substation main transformer and the near-zone compensation node is determined according to the preset upper limit threshold of reactive power exchange. If the reactive power exchange does not exceed the limit, the adjustment of the reactive power compensation strategy is completed. If the reactive power exchange exceeds the limit, iterate the above steps to determine whether there is a margin in the reactive power compensation resources near the main transformer of the AC substation, until the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power exchange all meet the requirements, and complete the adjustment of the reactive power compensation strategy.

2. The method according to claim 1, characterized in that, Using the equivalent model of the interconnected system, based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit, the voltage of the AC substation main transformer near-zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power electrical quantity flowing between the AC substation main transformer near-zone and the main transformer are output, including: Calculate the voltage of the near-zone compensation node of the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the power angle of the first unit relative to the second unit based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit. The reactive power electrical quantity flowing between the AC substation main transformer near-zone compensation node, the AC substation main transformer compensation node voltage, and the power angle of the first unit relative to the second unit are calculated.

3. The method according to claim 2, characterized in that, Using the equivalent model of the interconnected system, and based on the equivalent electrical quantity parameters of the first unit and the second unit, the calculation formulas for the voltage of the AC substation main transformer near-zone compensation node, the AC substation main transformer compensation node voltage, and the reactive power electrical quantity flowing between the AC substation main transformer near-zone and the main transformer are as follows: Calculate the direct connection impedance between the first unit and the second unit according to equation (1). x : （1） Calculate the power angle according to formula (2) : （2） Calculate the voltage of the near-zone compensation node of the main transformer in the AC substation according to equations (3) to (6). : （3） （4） （5） （6） Calculate the main transformer compensation node voltage of the AC substation according to equations (7) to (8). : （7） （8） The reactive power exchange between the near zone of the main transformer and the main transformer in the AC substation is calculated according to equations (9) to (11). Q : （9） （10） （11） in, E 1 represents the equivalent electromotive force of the first unit. The equivalent potential vector form of the first unit x 1 represents the equivalent reactance of the first unit. E 2 represents the equivalent electromotive force of the second unit. The equivalent potential vector form of the second unit x 2 represents the equivalent reactance of the second unit. P For the transfer of active power between the two systems, x 0 represents the electrical distance between the main transformer and the adjacent section of the main transformer in an AC substation. x 01 Equivalent parameters of reactive power compensation capacity in the vicinity of the main transformer x 02 The equivalent parameters of the reactive power compensation capacity of the main transformer. For the near-zone compensation node voltage of the main transformer in AC substation, For the main transformer bus voltage of AC substation, The power angle of the first unit relative to the second unit, Q For reactive power flowing between the near zone and the main transformer in an AC substation, For the current vector flowing between the near zone of the main transformer and the main transformer in an AC substation, , They are respectively middle , proportionality coefficient , They are respectively middle , proportionality coefficient , They are respectively middle , The proportionality coefficient.

4. The method according to claim 3, characterized in that, Based on pre-set criteria and the reactive power electrical quantities, the direction of reactive power flow is determined, including: If the reactive power electrical quantity is greater than a preset threshold, it is determined that the reactive power flows from the near zone of the main transformer to the main transformer in the AC substation. If the reactive power electrical quantity is less than the preset threshold, it is determined that the reactive power flows from the main transformer of the AC substation to the near zone of the main transformer; If the reactive power electrical quantity is equal to the preset threshold, it is determined that there is no reactive power flow.

5. The method according to claim 4, characterized in that, The operation of determining whether the voltage of the near-zone compensation node of the main transformer in the AC substation and the voltage of the compensation node of the main transformer in the AC substation are over-voltage based on a preset maximum voltage operating threshold also includes: If neither the voltage of the near-zone compensation node of the AC substation main transformer nor the voltage of the AC substation main transformer compensation node exceeds the voltage limit, the reactive power exchange between the AC substation main transformer and the near-zone compensation node is determined according to the preset upper limit threshold of reactive power exchange. If the reactive power exchange does not exceed the limit, the strategy adjustment is completed. If the reactive power exchange exceeds the limit, determine whether there is a margin in the reactive power compensation resources near the main transformer of the AC substation. If there is no margin in the reactive power compensation resources, select to put capacitors on / turn off reactors on the low-voltage side of the main transformer, restore the reactive power compensation strategy near the main transformer of the AC substation, recalculate the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power exchange, and iterate the above steps. If there is a margin in the reactive power compensation resources near the main transformer of the AC substation, select to put in a reactor or turn off a capacitor in the near area of ​​the main transformer, recalculate the reactive power exchange amount, and determine whether it exceeds the limit. If the reactive power exchange amount exceeds the limit, iterate the above steps. If the reactive power exchange amount does not exceed the limit, determine whether the voltage of the AC substation main transformer near-zone compensation node and the voltage of the AC substation main transformer compensation node are below the low voltage limit. If either the voltage of the AC substation main transformer near-zone compensation node or the voltage of the AC substation main transformer compensation node exceeds the low voltage limit, select to put on a capacitor / turn off a reactor on the low voltage side of the main transformer, restore the AC substation main transformer near-zone reactive power compensation strategy, recalculate the voltage of the AC substation main transformer near-zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power exchange amount, and iterate the above steps. The reactive power compensation strategy is adjusted when neither the voltage of the near-zone compensation node of the main transformer in the AC substation nor the voltage of the compensation node of the main transformer in the AC substation exceeds the low voltage limit.

6. The method according to claim 4, characterized in that, When the reactive power flows from the main transformer of the AC substation to the near zone of the main transformer, an adjustment scheme for the reactive power compensation strategy is determined based on the direction of the reactive power flow, including: Based on the preset maximum operating voltage threshold, determine whether the voltage of the near-zone compensation node of the AC substation main transformer and the voltage of the compensation node of the AC substation main transformer are over-voltage or exceed the limit. If either the voltage of the main transformer near the compensation node of the AC substation or the voltage of the main transformer compensation node of the AC substation exceeds the overvoltage limit, determine whether there is a margin in the reactive power compensation resources near the main transformer of the AC substation. If there is no margin in the reactive power compensation resources, select to put in a reactor / turn off a capacitor on the low-voltage side of the main transformer, restore the reactive power compensation strategy of the main transformer near the AC substation, recalculate the voltage of the main transformer near the compensation node of the AC substation, the voltage of the main transformer compensation node of the AC substation, and the reactive power exchange quantity, and iterate the above steps. If there is a margin in the reactive power compensation resources near the main transformer of the AC substation, select to add reactors or turn off capacitors in the near area of ​​the main transformer, recalculate the voltage of the compensation node in the near area of ​​the main transformer of the AC substation and the voltage of the compensation node of the main transformer of the AC substation, and determine whether the limit is exceeded. If either the voltage of the compensation node in the near area of ​​the main transformer of the AC substation or the voltage of the compensation node of the main transformer of the AC substation exceeds the overvoltage limit, iterate the above steps. If neither the voltage of the near-zone compensation node of the AC substation main transformer nor the voltage of the AC substation main transformer compensation node exceeds the voltage limit, based on the preset minimum voltage operating threshold, it is determined whether the voltage of the near-zone compensation node of the AC substation main transformer nor the voltage of the AC substation main transformer compensation node exceeds the low voltage limit. If either the voltage of the near-zone compensation node of the AC substation main transformer or the voltage of the AC substation main transformer compensation node exceeds the low voltage limit, a capacitor is switched on / a reactor is switched off on the low-voltage side of the main transformer, the reactive power compensation strategy of the near-zone compensation node of the AC substation main transformer is restored, the voltage of the near-zone compensation node of the AC substation main transformer, the voltage of the AC substation main transformer compensation node, and the reactive power exchange are recalculated, and the above steps are iterated. If neither the voltage of the near-zone compensation node of the AC substation main transformer nor the voltage of the AC substation main transformer compensation node exceeds the low voltage limit, the reactive power exchange between the AC substation main transformer and the near-zone compensation node is determined according to the preset upper limit threshold of reactive power exchange. If the reactive power exchange does not exceed the limit, the adjustment of the reactive power compensation strategy is completed. If the reactive power exchange exceeds the limit, select to add a reactor or turn off a capacitor on the low-voltage side of the main transformer to restore the reactive power compensation strategy of the AC substation main transformer near zone. Recalculate the voltage of the AC substation main transformer near zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power exchange. Iterate the above steps until the voltage of the AC substation main transformer near zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power exchange all meet the requirements, thus completing the adjustment of the reactive power compensation strategy.

7. The method according to claim 6, characterized in that, Based on a pre-set maximum operating voltage threshold, determine whether the voltage of the near-zone compensation node of the main transformer in the AC substation and the voltage of the compensation node of the main transformer in the AC substation are over-voltage or exceed the limit, including: If neither the voltage of the near-zone compensation node of the AC substation main transformer nor the voltage of the AC substation main transformer compensation node exceeds the voltage limit, the reactive power exchange between the AC substation main transformer and the near-zone compensation node is determined according to the preset upper limit threshold of reactive power exchange. If the reactive power exchange does not exceed the limit, the strategy adjustment is completed. If the reactive power exchange exceeds the limit, determine whether there is a margin in the reactive power compensation resources near the main transformer of the AC substation. If there is no margin in the reactive power compensation resources, select to put in a reactor / turn off a capacitor on the low-voltage side of the main transformer, restore the reactive power compensation strategy near the main transformer of the AC substation, recalculate the voltage of the compensation node near the main transformer of the AC substation, the voltage of the compensation node of the main transformer of the AC substation, and the reactive power exchange, and iterate the above steps. If there is a margin in the reactive power compensation resources near the main transformer of the AC substation, select to put on capacitors / turn off reactors in the near area of ​​the main transformer, recalculate the reactive power exchange amount, and determine whether it exceeds the limit. If the reactive power exchange amount exceeds the limit, iterate the above steps. If the reactive power exchange amount does not exceed the limit, determine whether the voltage of the AC substation main transformer near-zone compensation node and the voltage of the AC substation main transformer compensation node are over-voltage limits. If either the voltage of the AC substation main transformer near-zone compensation node or the voltage of the AC substation main transformer compensation node exceeds the voltage limit, select to add reactors / turn off capacitors on the low-voltage side of the main transformer, restore the AC substation main transformer near-zone reactive power compensation strategy, recalculate the voltage of the AC substation main transformer near-zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power exchange amount, and iterate the above steps. The reactive power compensation strategy is adjusted when neither the voltage of the near-zone compensation node of the main transformer in the AC substation nor the voltage of the compensation node of the main transformer in the AC substation exceeds the low voltage limit.

8. A real-time adjustment device for overvoltage and reactive power compensation strategies in AC substations, used to implement the method described in claim 1, characterized in that, include: The acquisition module is used to acquire, in real time, the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit connected to the AC substation, based on the equivalent model of the interconnected system. The output module is used to output the voltage of the AC substation main transformer near-zone compensation node, the voltage of the AC substation main transformer compensation node, and the reactive power electrical quantity flowing between the AC substation main transformer near-zone and the main transformer, based on the equivalent electrical quantity parameters of the first unit and the equivalent electrical quantity parameters of the second unit using the equivalent model of the interconnected system. The first determining module is used to determine the direction of reactive power flow based on a pre-set criterion and the reactive power electrical quantity. The second determining module is used to determine the adjustment scheme of the reactive power compensation strategy based on the direction of the reactive power flow.

9. A computer-readable storage medium, characterized in that, The storage medium stores a computer program for performing the method described in any one of claims 1-7.

10. An electronic device, characterized in that, The electronic device includes: processor; Memory used to store the processor's executable instructions; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1-7.

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