False power-on protection method and system based on grid-connected state

Abstract

The invention discloses a mistaken power-on protection method and system based on a grid-connected state. The method comprises the following steps: replacing a single auxiliary contact of a grid-connected switch with a unit grid-connected state as an input condition of mistaken power-on protection; judging whether the grid-connected state is abnormal or not: if the grid-connected state is normal, taking the grid-connected state and the'or logic 'of the low-frequency and low-voltage element as a false power-on protection action criterion, and if the grid-connected state is abnormal, quitting the grid-connected state criterion, and taking the low-frequency and low-voltage element as the false power-on protection action criterion independently; comprehensively judging whether to quit false power-on protection or not according to the grid-connected state, the machine end current auxiliary criterion and the high-voltage side current auxiliary criterion; and starting a false power-on protection action logic according to the false power-on protection criterion combination. According to the invention, whether the unit is connected to the grid or not and whether the grid-connected state is abnormal can be judged, and related criteria and false power-on protection are sent and locked.

Description

Technical Field

[0001] The present invention relates to the technical field of relay protection of electric power systems, and in particular to a method and system for protecting against false power-on based on a grid-connected state. Background Art

[0002] There are generally two types of main wiring configurations for generator-transformer groups: with machine-end circuit breakers and without machine-end circuit breakers. For main wiring configurations without machine-end circuit breakers, the high-voltage side circuit breaker is generally used as the grid-connected switch; for main wiring configurations with machine-end circuit breakers, the machine-end circuit breaker is generally used as the grid-connected switch. At present, due to changes in the operating mode, the grid-connected switch may change. For example, in general, the machine-end circuit breaker is used as the grid-connected switch. When the grid is connected after island operation, the grid-connected switch is converted to the high-voltage side circuit breaker. The existing false power-on protection can only fix a certain circuit breaker as the grid-connected switch. When the grid-connected switch changes, the false power-on protection may exit operation, making it difficult to protect the unit.

[0003] In addition, the false power-on protection should be automatically activated after the unit is disconnected and automatically deactivated after being connected to the grid. The existing false power-on protection is considered to play a protective role during asynchronous grid connection. The logical relationship between the grid connection contact and the low-frequency and low-voltage action element is designed as "or logic". The low-frequency and low-voltage elements will continue to operate after being connected to the grid, so the false power-on protection will not automatically deactivate after being connected to the grid. In order to avoid false operation of the false power-on protection in the event of a fault, the set value of the low-voltage element is set to a lower value (generally around 20V at the online voltage). Some false power-on protection principles deactivate the operation through the auxiliary contacts of the grid-connected switch after the unit is connected to the grid. However, the auxiliary contacts of a single grid-connected switch are not reliable. After a fault in the DC system of the power plant or the DC disappears, the false power-on protection may be mistakenly activated, resulting in false operation of the false power-on protection.

[0004] In order to solve the above problems, there is an urgent need for a false power-on protection solution based on grid-connected status identification. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above existing problems, the present invention is proposed.

[0007] Therefore, the present invention provides a method and system for false power-on protection based on the grid-connected state to solve the problem that the false power-on protection is difficult to protect the unit after the grid-connected switch changes.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] In a first aspect, the present invention provides a method for protecting against an incorrect power-on condition based on a grid-connected state, comprising:

[0010] Collect the generator terminal current, main transformer high voltage side current, generator terminal voltage amplitude and frequency and grid connection status;

[0011] Use overcurrent components, low-frequency and low-voltage components, and grid-connected status components to pre-process the collected data and determine whether the grid-connected status is abnormal;

[0012] If the grid-connected state is abnormal, an abnormal grid-connected state alarm is issued and the grid-connected state judgment criteria are exited;

[0013] If the grid-connected state is normal, the system will determine whether the generator has been connected to the grid based on the grid-connected state judgment rule and the current auxiliary judgment criterion. If it has been connected to the grid, the system will automatically exit the false power-on protection; if it has not been connected to the grid, the system will automatically enter the false power-on protection.

[0014] Design the false power-on protection criterion based on the generator terminal current, the main transformer high-voltage side current, the amplitude and frequency of the generator terminal voltage and the grid connection status;

[0015] Based on the false power-on protection criterion, the false power-on protection action logic is started through the combination of the criterion to form a false power-on protection scheme.

[0016] As a preferred solution of the grid-connected state-based false power-on protection method of the present invention, wherein:

[0017] The grid connection status includes the following rules:

[0018] If there is no circuit breaker at the generator end, it is considered that the generator end is connected to the low-voltage side of the main transformer;

[0019] If the machine-side circuit breaker is closed and the generator-side current I g ≥I LowVal1 , it is considered that the generator end is connected to the low-voltage side of the main transformer;

[0020] If the machine-side current I g ≥I LowVal2 , it is considered that the generator end is connected to the low-voltage side of the main transformer;

[0021] If there is no high-voltage side switch 1 and no high-voltage side switch 2, it is considered that the main transformer is connected to the main grid;

[0022] If the high-voltage side switch 1 is closed and the high-voltage side current of the main transformer I h ≥I LoweVal3 , then the main transformer is considered to be connected to the main grid;

[0023] If the high-voltage side switch 1 is closed and the sum of the currents I h1 +I h2 ≥I LowVal3 , then the main transformer is considered to be connected to the main grid;

[0024] If the high-voltage side switch 2 is closed and the high-voltage side current I h ≥I LoweVal3 , then the main transformer is considered to be connected to the main grid;

[0025] If the high-voltage side switch 2 is closed and the sum of the currents I h1 +I h2 ≥I LowVal3 , then the main transformer is considered to be connected to the main grid;

[0026] If the high voltage side current of the main transformer I h ≥I LoweVal4 , then the main transformer is considered to be connected to the main grid;

[0027] If the sum of the currents of switch 1 and switch 2 on the high-voltage side of the main transformer is h1 +I h2 ≥I LowVal4 , then the main transformer is considered to be connected to the main grid;

[0028] If the generator end is connected to the low-voltage side of the main transformer, and the main transformer is connected to the main grid, it means grid connection, and the grid connection status is 1;

[0029] If the generator end is not connected to the low-voltage side of the main transformer, it means that it is not connected to the grid, and the grid connection status is 0;

[0030] If the main transformer is not connected to the main grid, it means that it is not connected to the grid, and the grid connection status is 0;

[0031] Among them, I LowVal1 is the first current threshold, I LowVal2 is the second current threshold, I LowVal3 is the third current threshold, I LowVal4 It is the fourth current threshold.

[0032] As a preferred solution of the grid-connected state-based false power-on protection method of the present invention, wherein:

[0033] The determination of whether the grid-connected state is abnormal includes the following rules:

[0034] If the grid-connected state is 0 and the machine-end current I g ≥I LowVal5 And the main transformer high voltage side current I h ≥I LowVal6 , it is judged that the grid-connected state is abnormal;

[0035] If the grid-connected state is 0 and the machine-end current I g ≥I LowVal5 And the sum of the currents of switch 1 and switch 2 on the high side is I h1 +I h2 ≥I LowVal6 , it is judged that the grid-connected state is abnormal;

[0036] If the grid-connected state is 1 and the machine-end current I g <I LowVal5 , it is judged that the grid-connected state is abnormal;

[0037] If the grid-connected state is 1 and the high-voltage side current of the main transformer I h <I LowVal6 , it is judged that the grid-connected state is abnormal;

[0038] If the grid connection state is 1 and the sum current of switch 1 and switch 2 on the high side is I h1 +I h2 <I LowVal6 , it is judged that the grid-connected state is abnormal;

[0039] Among them, I LowVal5 is the fifth current threshold, I LowVal6 It is the sixth current threshold.

[0040] As a preferred solution of the grid-connected state-based false power-on protection method of the present invention, wherein:

[0041] The method of determining whether the generator has been connected to the grid includes the following rules:

[0042] If the grid-connected state is 0, the machine-end current I g ≥I LowVal5 And the main transformer high voltage side current I h ≥I LowVal6 , the unit has been connected to the grid, and the error power-on protection has stopped operation;

[0043] If the grid-connected state is 0, the machine-end current I g ≥I LowVal5 And the sum of the currents of switch 1 and switch 2 on the high side is I h1 +I h2 ≥I LowVal6 , the unit has been connected to the grid, and the error power-on protection has stopped operation;

[0044] If the grid-connected state is 1, the machine-end current I g ≥I LowVal5 And the main transformer high voltage side current I h ≥I LowVal6 , the unit has been connected to the grid, and the error power-on protection has stopped operation;

[0045] If the grid-connected state is 1, the machine-end current I g ≥I LowVal5 And the sum of the currents of switch 1 and switch 2 on the high side is I h1 +I h2 ≥I LowVal6 , the unit has been connected to the grid, and the error power-on protection has stopped operation;

[0046] If the grid-connected state is 0, the machine-end current I g <I LowVal5 , the unit is not connected to the grid, and the false power-on protection is put into operation;

[0047] If the grid-connected state is 0, the high-voltage side current of the main transformer I h <I LowVal6 , the unit is not connected to the grid, and the false power-on protection is put into operation;

[0048] If the grid-connected state is 0, the sum current of switch 1 and switch 2 on the high-voltage side I h1 +I h2 <I LowVal6 , the unit is not connected to the grid, and the false power-on protection is put into operation;

[0049] If the grid-connected state is 1, the machine-end current I g <I LowVal5 , the unit is not connected to the grid, and the false power-on protection is put into operation;

[0050] If the grid-connected state is 1, the high-voltage side current of the main transformer I h <I LowVal6 , the unit is not connected to the grid, and the false power-on protection is put into operation;

[0051] If the grid connection state is 1 and the sum current of switch 1 and switch 2 on the high side is I h1 +I h2 <I LowVal6 , the unit is not connected to the grid and the error power-on protection is put into operation.

[0052] As a preferred solution of the grid-connected state-based false power-on protection method of the present invention, wherein:

[0053] The designed erroneous power-on protection criterion includes a first criterion, a second criterion, a third criterion, a fourth criterion, a fifth criterion, a sixth criterion, a seventh criterion, and an eighth criterion;

[0054] The first criterion is the machine-end current I g >I Set1 , I Set1 It is the first current action setting;

[0055] The second criterion is the high voltage side current I of the main transformer h >I Set2, or the sum of the currents I of switch 1 and switch 2 on the high voltage side of the main transformer h1 +I h2 >I set2 , I set2 It is the second current action setting;

[0056] The third criterion is the generator terminal voltage U g <U Set , U Set It is the low voltage action setting value;

[0057] The fourth criterion is the terminal frequency F g <F Set , F Set It is the setting value of low frequency action;

[0058] The fifth criterion is that the unit is not connected to the grid and the grid connection status is normal;

[0059] The sixth criterion is that the unit is not connected to the grid and the grid connection state is abnormal;

[0060] The seventh criterion is that the unit has been connected to the grid and the grid connection status is normal;

[0061] The eighth criterion is that the unit has been connected to the grid and the grid connection state is abnormal;

[0062] As a preferred solution of the grid-connected state-based false power-on protection method of the present invention, wherein:

[0063] The combination of criteria for starting the false power-on protection action logic includes a first combination, a second combination, a third combination, a fourth combination, a fifth combination, a sixth combination and a seventh combination;

[0064] If any combination is met, the false power-on protection action logic is activated;

[0065] The first combination includes simultaneously satisfying the first criterion, the second criterion, the third criterion and the sixth criterion;

[0066] The second combination includes satisfying the first criterion, the second criterion, the fourth criterion and the sixth criterion at the same time;

[0067] The third combination includes satisfying the first criterion, the second criterion and the fifth criterion at the same time;

[0068] The fourth combination includes satisfying the first criterion, the second criterion, the third criterion and the fifth criterion at the same time;

[0069] The fifth combination includes satisfying the first criterion, the second criterion, the fourth criterion and the fifth criterion at the same time;

[0070] The sixth combination includes satisfying the first criterion, the second criterion, the third criterion, the fourth criterion and the fifth criterion at the same time;

[0071] The seventh combination includes satisfying the first criterion, the second criterion, the third criterion, the fourth criterion and the sixth criterion at the same time;

[0072] When the duration of the third criterion exceeds T1, the third criterion is considered to be established;

[0073] When the duration of the fourth criterion exceeds T1, the fourth criterion is considered to be established;

[0074] When the duration of the third criterion exceeds T2, it is considered that the third criterion returns;

[0075] When the fourth criterion lasts longer than T2, it is considered that the fourth criterion returns;

[0076] When the fifth criterion lasts longer than T3, the fifth criterion is considered to be established;

[0077] When the duration of the sixth criterion exceeds T3, the sixth criterion is considered to be established and the fifth criterion is locked;

[0078] When the fifth criterion lasts longer than T4, it is considered that the fifth criterion has returned;

[0079] When the duration of the seventh criterion exceeds T4, the seventh criterion is considered to be established and the false power-on protection is locked;

[0080] When the duration of the eighth criterion exceeds T4, the eighth criterion is considered to be established and the false power-on protection is locked;

[0081] When all the combinations of false power-on criteria are met and the system waiting time exceeds T5, it is considered that the false power-on protection is activated and the protection action is executed.

[0082] As a preferred solution of the grid-connected state-based false power-on protection method of the present invention, wherein:

[0083] The fifth criterion includes the following rules:

[0084] If the grid-connected state is 0, the machine-end current I g <I LowVal5 And the main transformer high voltage side current I h <I LowVal6 , the unit is not connected to the grid, and the grid connection status is normal;

[0085] If the grid-connected state is 0, the machine-end current I g <I LowVal5 And the sum of the currents of switch 1 and switch 2 on the high side is I h1 +I h2 <I LowVal6 , the unit is not connected to the grid, and the grid connection status is normal;

[0086] The sixth criterion includes the following rules:

[0087] If the grid-connected state is 0 and the machine-end current I g ≥I LowVal5 , the unit is not connected to the grid and the grid connection status is abnormal;

[0088] If the grid-connected state is 0 and the high-voltage side current I h ≥I LowVal6 , the unit is not connected to the grid and the grid connection status is abnormal;

[0089] If the grid-connected state is 0 and the sum of the currents of switch 1 and switch 2 on the high-voltage side is I h1 +I h2 ≥I LowVal6 , the unit is not connected to the grid and the grid connection status is abnormal;

[0090] The seventh criterion includes the following rules:

[0091] If the grid-connected state is 1, the machine-end current I g ≥I LowVal5 And the main transformer high voltage side current I h ≥I LowVal6 , the unit has been connected to the grid and the grid connection status is normal;

[0092] If the grid-connected state is 1, the machine-end current I g ≥I LowVal5 And the sum of the currents of switch 1 and switch 2 on the high side is I h1 +I h2 ≥I LowVal6 , the unit has been connected to the grid and the grid connection status is normal;

[0093] The eighth criterion includes the following rules:

[0094] If the grid-connected state is 1 and the machine-end current I g <I LowVal5 , the unit has been connected to the grid, and the grid connection status is abnormal;

[0095] If the grid-connected state is 1 and the high-voltage side current of the main transformer I h <I LowVal6 , the unit has been connected to the grid, and the grid connection status is abnormal;

[0096] If the grid connection state is 1 and the sum current of switch 1 and switch 2 on the high side is I h1 +I h2 <I LowVal6 , the unit has been connected to the grid, and the grid connection status is abnormal.

[0097] In a second aspect, the present invention provides a grid-connected state-based false power-on protection system, comprising:

[0098] The acquisition module is used to collect the generator terminal current, the main transformer high-voltage side current, the generator terminal voltage amplitude and frequency and the grid-connected status;

[0099] The abnormality identification module is used to pre-process the collected data using overcurrent components, low-frequency and low-voltage components, and grid-connected status components to determine whether the grid-connected status is abnormal;

[0100] The first abnormal module is used to issue an abnormal grid state alarm and exit the grid state judgment if the grid state is abnormal;

[0101] The second abnormal module is used to determine whether the generator has been connected to the grid according to the grid state determination rule and the current auxiliary determination criterion if the grid state is normal. If it has been connected to the grid, it will automatically exit the false power-on protection; if it has not been connected to the grid, it will automatically enter the false power-on protection;

[0102] A design module for designing the false power-on protection criterion based on the generator terminal current, the main transformer high-voltage side current, the amplitude and frequency of the generator terminal voltage, and the grid connection status;

[0103] The result judgment module is used to start the false power-on protection action logic based on the false power-on protection judgment criterion through the combination of judgment criteria to form a false power-on protection scheme.

[0104] In a third aspect, the present invention provides a computing device, comprising:

[0105] Memory, used to store programs;

[0106] A processor is used to execute the computer executable instructions, which, when executed by the processor, implement the steps of the grid-connected state-based false power-on protection method.

[0107] In a fourth aspect, the present invention provides a computer-readable storage medium, comprising: when the program is executed by a processor, the steps of implementing the grid-connected state-based false power-on protection method.

[0108] The beneficial effects of the present invention are as follows: based on the false power-on protection scheme of the low-frequency and low-voltage principle, the present invention adopts the grid-connected state of the unit instead of the single auxiliary contact of the grid-connected switch as the input condition of the false power-on protection, and judges whether the grid-connected state is abnormal. If the grid-connected state is abnormal, an abnormal grid-connected state alarm is issued and the grid-connected state element is exited. The false power-on protection scheme is composed of low-frequency and low-voltage elements and overcurrent elements, which improves the accuracy of the false power-on protection judgment criterion. The grid-connected state of the unit and the auxiliary judgment criteria of electrical quantities are used to judge whether the unit is grid-connected. After the grid is connected, the false power-on protection is automatically exited, which improves the operation reliability of the false power-on protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0110] Figure 1 A basic flow chart of a method for protecting against an incorrect power-on condition based on a grid-connected state provided by an embodiment of the present invention;

[0111] Figure 2 An overall protection logic diagram of a grid-connected state-based false power-on protection method provided by an embodiment of the present invention.

[0112] Figure 3 A logical schematic diagram of grid-connected state determination of a grid-connected state-based false power-on protection method provided by an embodiment of the present invention;

[0113] Figure 4 A logic diagram of whether a unit is grid-connected and whether the grid-connected state is abnormal is provided for a method for false power-on protection based on the grid-connected state according to an embodiment of the present invention. DETAILED DESCRIPTION

[0114] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0115] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0116] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0117] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0118] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0119] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0120] Example 1

[0121] Reference Figure 1-4 , is an embodiment of the present invention, and provides a method for protecting against power-on errors based on the grid-connected state, such as Figure 1 , as shown in 2, comprising the following steps:

[0122] S1: Collect the generator terminal current, the main transformer high voltage side current, the generator terminal voltage amplitude and frequency, and the grid connection status;

[0123] In the embodiment of the present application, on the basis of the false power-on protection scheme of the low-frequency and low-voltage principle, the grid-connected state of the unit is used instead of the single auxiliary contact of the grid-connected switch as the input condition of the false power-on protection;

[0124] In the embodiments of the present application, Figure 3 As shown, the designed grid-connected status judgment rule is that the generator end is connected to the low-voltage side of the main transformer, and the main transformer is connected to the main grid.

[0125] In the embodiment of the present application, the connection judgment rule between the generator terminal and the low-voltage side of the main transformer is:

[0126] The first criterion:

[0127] There is no circuit breaker at the generator end;

[0128] The second criterion:

[0129] The machine-end circuit breaker is closed and the generator-end current I g ≥I LowVal1 , I LowVal1 is the first current threshold;

[0130] The third criterion:

[0131] Generator terminal current I g ≥I LowVal2 , I LowVal2 is the second current threshold;

[0132] In the embodiment of the present application, the logical relationship between the above three criteria is "OR logic".

[0133] In the embodiment of the present application, the main transformer and the main grid connection judgment rule is:

[0134] The first criterion:

[0135] There is no high-voltage side switch 1, and there is no high-voltage side switch 2;

[0136] The second criterion:

[0137] The high-voltage side switch 1 is closed, or the high-voltage side switch 2 is closed and the main transformer high-voltage side current I h ≥I LowVal3 , or the sum of the currents I of switch 1 and switch 2 on the high voltage side of the main transformer h1 +I h2 ≥I LowVal3 , I LowVal3 is the third current threshold;

[0138] The third criterion:

[0139] Main transformer high voltage side current I h ≥I LowVal4 , or the sum of the currents I of switch 1 and switch 2 on the high voltage side of the main transformer h1 +I h2 ≥I LowVal4 , I LowVal4 is the fourth current threshold;

[0140] In the embodiment of the present application, the logical relationship between the above three criteria is "OR logic"

[0141] In an embodiment of the present application, the first current threshold is 0.01 times the rated current of the machine end; the second current threshold is 0.02 times the rated current of the machine end; the third current threshold is 0.01 times the rated current of the high-voltage side; and the fourth current threshold is 0.02 times the rated current of the high-voltage side.

[0142] S2: pre-process the collected data using overcurrent components, low-frequency and low-voltage components, and grid-connected status components to determine whether the grid-connected status is abnormal;

[0143] In the embodiment of the present application, the judgment rule of abnormal grid connection status is designed as follows:

[0144] The first criterion:

[0145] ①The grid-connected state is 0;

[0146] ② Machine-end current I g ≥I LowVal5 ;

[0147] ③ High voltage side current I h ≥I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 ≥I LowVal6 ;

[0148] The second criterion:

[0149] ① The grid-connected status is 1;

[0150] ② Machine-end current I g <I LowVal5 Or high voltage side current I h <I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 <I LowVal6 ;

[0151] Among them, I LowVal5 is the fifth current threshold, I LowVal6 It is the sixth current threshold. If any one of the criteria is met, it is judged that the grid-connected state is abnormal.

[0152] S3: If the grid-connected state is abnormal, an abnormal grid-connected state alarm is issued and the grid-connected state judgment criteria are exited;

[0153] S4: If the grid-connected state is normal, determine whether the generator has been connected to the grid according to the grid-connected state judgment rule and the current auxiliary judgment criterion. If it has been connected to the grid, the false power-on protection will be automatically exited; if it has not been connected to the grid, the false power-on protection will be automatically activated;

[0154] In the embodiment of the present application, the designed error power-on protection exit judgment rule is:

[0155] The first criterion:

[0156] ①The grid-connected state is 0;

[0157] ② Machine-end current I g ≥I LowVal5 ;

[0158] ③ High voltage side current I h ≥I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 ≥I LowVal6 ;

[0159] The second criterion:

[0160] ① The grid-connected status is 1;

[0161] ② Machine-end current I g ≥I LowVal5 ;

[0162] ③Main transformer high voltage side current I h ≥I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +

[0163] I h2 ≥I LowVal6 ;

[0164] In the embodiment of the present application, if any one of the above criteria is met, the false power-on protection will exit operation.

[0165] In the embodiment of the present application, the designed error power-on protection input judgment rule is:

[0166] The first criterion:

[0167] ①The grid-connected state is 0;

[0168] ② Machine-end current I g <I LowVal5 , or the main transformer high voltage side current I h <I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 <I LowVal6 ;I LowVal5 The end is the fifth current threshold; I LowVal6 The end is the sixth current threshold;

[0169] The second criterion:

[0170] ① The grid-connected status is 1;

[0171] ② Machine-end current I g <I LowVal5 Or high voltage side current I h <I LowVal6 ;

[0172] The third criterion:

[0173] ① The grid-connected status is 1;

[0174] ② The sum of the currents of switch 1 and switch 2 on the high-voltage side I h1 +I h2 <I LowVal6 ;

[0175] In the embodiment of the present application, if any one of the above criteria is met, the false power-on protection is put into operation.

[0176] S5: Design the false power-on protection criterion based on the generator terminal current, the main transformer high-voltage side current, the amplitude and frequency of the generator terminal voltage and the grid connection status;

[0177] In the embodiment of the present application, the false power-on protection criteria include:

[0178] Criteria 1: Machine-end current I g >I set1 , I Set1 It is the first current action setting;

[0179] Criteria 2: Main transformer high voltage side current I h >I Set2 , or the sum of the currents I of switch 1 and switch 2 on the high voltage side of the main transformer h1 +I h2 >I set2 , I set2 It is the second current action setting;

[0180] Criterion 3: Generator terminal voltage U g <U Set , U set It is the low voltage action setting value;

[0181] Criterion 4: Terminal frequency F g <F set , F Set It is the setting value of low frequency action;

[0182] Criteria 5: The unit is not connected to the grid and the grid connection status is normal;

[0183] Criteria 6: The unit is not connected to the grid and the grid connection status is abnormal;

[0184] Criteria 7: The unit has been connected to the grid and the grid connection status is normal;

[0185] Criteria 8: The unit has been connected to the grid, and the grid connection status is abnormal;

[0186] In the embodiments of the present application, Figure 4 As shown, the grid-connected state normal or abnormal judgment criteria include judgment 5, judgment 6, judgment 7, and judgment 8, which can be automatically generated by the generator terminal current, the main transformer high-voltage side current and the grid-connected state through logical judgment rules, specifically:

[0187] Criterion 5:

[0188] ①The grid-connected state is 0;

[0189] ② Machine-end current I g <I LowVal5 ;I LowVal5 The end is the fifth current threshold;

[0190] ③Main transformer high voltage side current I h <I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 <I LowVal6 ;I LowVal6 The end is the sixth current threshold;

[0191] Criterion 6:

[0192] ①The grid-connected state is 0;

[0193] ② Machine-end current I g ≥I LowVal5 , or high voltage side current I h ≥I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 ≥I LowVal6 ;

[0194] Criterion 7:

[0195] ① The grid-connected status is 1;

[0196] ② Machine-end current I g ≥I LowVal5 ;

[0197] ③Main transformer high voltage side current I h ≥I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 ≥I LowVal6 ;

[0198] Criterion 8:

[0199] ① The grid-connected status is 1;

[0200] ② Machine-end current I g <I LowVal5 Or high voltage side current I h <I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 <I LowVal6 ;

[0201] It should be noted that the false power-on protection scheme can also be established by using the grid-connected switch contact instead of the grid-connected state. If the circuit breaker split contact is used, the judgment rules of criteria 5, 6, 7, and 8 are:

[0202] Criterion 5:

[0203] ① The circuit breaker open contact state is 0;

[0204] ② Machine-end current I g <I LowVal5 ;

[0205] ③Main transformer high voltage side current I h <I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 <I LowVal6 ;

[0206] Criterion 6:

[0207] ① The circuit breaker open contact state is 0;

[0208] ② Machine-end current I g ≥I LowVal5 , or high voltage side current Ih ≥I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 ≥I LowVal6 ;

[0209] Criterion 7:

[0210] ① The circuit breaker open contact state is 1;

[0211] ② Machine-end current I g ≥I LowVal5 ;

[0212] ③Main transformer high voltage side current I h ≥I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1 +I h2 ≥I LowVal6 ;

[0213] Criterion 8:

[0214] ① The circuit breaker open contact state is 1;

[0215] ② Machine-end current I g <I LowVal5 Or high voltage side current I h <I LowVal6 , or the sum of the currents of high-side switch 1 and switch 2 I h1+I h2 <I LowVal6 ;

[0216] Among them, I LowVal5 0.04 times the rated current of the machine end, I LowVal6 0.04 times the rated current on the high voltage side.

[0217] S6: Based on the false power-on protection criterion, the false power-on protection action logic is started through the combination of the criterion to form a false power-on protection scheme.

[0218] In the embodiment of the present application, the protection criteria can be combined to meet the false power-on protection action conditions and start the false power-on protection action logic, including:

[0219] Combination 1: Criteria 1, 2, 3, and 6 are met at the same time;

[0220] Combination 2: Criteria 1, 2, 4, and 6 are met at the same time;

[0221] Combination 3: Criteria 1, 2, and 5 are met at the same time;

[0222] Combination 4: Criteria 1, 2, 3, and 5 are met at the same time;

[0223] Combination 5: Criteria 1, 2, 4, and 5 are met at the same time;

[0224] Combination 6: Criteria 1, 2, 3, 4 and 5 are met at the same time;

[0225] Combination 7: Criteria 1, 2, 3, 4 and 6 are met at the same time;

[0226] In the embodiments of the present application, Figure 2 As shown, criterion 3 or criterion 4 is satisfied after delay T1, and the delay is widened by T2 after the criterion is returned; criterion 5 is satisfied after delay T3, and the delay is widened by T4 after the criterion is returned; criterion 6 is satisfied after delay T3, and criterion 5 is locked; criterion 7 or criterion 8 is satisfied after delay T4, and the false power-on protection is locked; after the false power-on protection criterion is satisfied, it acts on sending a signal or acting on the export after a delay of T5.

[0227] In the embodiments of the present application, in combination 1, combination 2, and combination 7, when criterion 6 is met, criterion 5 is locked because the unit is not connected to the grid and the false power-on protection is activated, but the grid-connected state is abnormal. To prevent the false power-on protection from malfunctioning or refusing to operate, the grid-connected state should no longer be used as the main criterion for the false power-on protection.

[0228] In the embodiment of the present application, in order to ensure the reliability of the criterion or the anti-shake judgment of the auxiliary contact of the circuit breaker, criterion 3 or criterion 4 needs to be satisfied after a delay of T1; criterion 5 and criterion 6 need to be satisfied after a delay of T3.

[0229] In the embodiment of the present application, in order to ensure reliable operation of the false power-on protection, after the return of criterion 3 or criterion 4, the T2 delay needs to be widened, and the T2 delay is greater than T5; after the return of criterion 5, the T4 delay needs to be widened, and the T4 delay is greater than T5. After the unit is connected to the grid, criterion 7 or criterion 8 may be met immediately. In order to ensure reliable operation of the protection, criterion 7 or criterion 8 needs to be met after a delay of T4 before locking the false power-on protection.

[0230] This embodiment also provides a grid-connected state-based false power-on protection system, including:

[0231] The acquisition module is used to collect the generator terminal current, the main transformer high-voltage side current, the generator terminal voltage amplitude and frequency and the grid-connected status;

[0232] The abnormality identification module is used to pre-process the collected data using overcurrent components, low-frequency and low-voltage components, and grid-connected status components to determine whether the grid-connected status is abnormal;

[0233] The first abnormal module is used to issue an abnormal grid state alarm and exit the grid state judgment if the grid state is abnormal;

[0234] The second abnormal module is used to determine whether the generator is in the grid-connected state according to the grid-connected state determination rule and the current auxiliary determination criterion if the grid-connected state is normal. If the generator is in the grid-connected state, the error power-on protection is automatically exited; if the generator is in the non-grid-connected state, the error power-on protection is automatically activated;

[0235] A design module for designing the false power-on protection criterion based on the generator terminal current, the main transformer high-voltage side current, the amplitude and frequency of the generator terminal voltage, and the grid connection status;

[0236] The result judgment module is used to start the false power-on protection action logic based on the false power-on protection judgment criterion through the combination of judgment criteria to form a false power-on protection scheme.

[0237] Furthermore, it also includes:

[0238] Memory, used to store programs;

[0239] The processor is used to load the program to execute the grid-connected state-based false power-on protection method.

[0240] This embodiment further provides a computer-readable storage medium storing a program, and when the program is executed by a processor, the method for protecting against incorrect power-on based on the grid-connected state is implemented.

[0241] The storage medium proposed in this embodiment and the grid-connected state-based false power-on protection method proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0242] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.

[0243] Example 2

[0244] This is an embodiment of the present invention, which provides a wrong power-on protection system based on the grid-connected state, including a collection module, an abnormality determination module, a first abnormality module, a second abnormality module, a design module and a result determination module;

[0245] In the embodiment of the present application, the acquisition module includes collecting the generator terminal current, the main transformer high voltage side current, the amplitude and frequency of the generator terminal voltage and the grid connection status;

[0246] In the embodiment of the present application, the designed grid-connected status determination rule is that the generator end is connected to the low-voltage side of the main transformer, and the main transformer is connected to the main power grid.

[0247] In the embodiment of the present application, the abnormality determination module includes using an overcurrent element, a low-frequency and low-voltage element, and a grid-connected state element to pre-process the collected data to determine whether the grid-connected state is abnormal;

[0248] In the embodiment of the present application, the first abnormal module includes issuing a grid-connected state abnormality alarm and exiting the grid-connected state judgment criterion if the grid-connected state is abnormal;

[0249] In the embodiment of the present application, the second abnormal module includes: if the grid-connected state is normal, it determines whether the generator has been connected to the grid according to the grid-connected state judgment rule and the current auxiliary judgment criterion, and if it has been connected to the grid, it automatically exits the false power-on protection; if it is not connected to the grid, it automatically enters the false power-on protection;

[0250] In the embodiment of the present application, the design module includes designing the false power-on protection criterion based on the generator terminal current, the main transformer high-voltage side current, the amplitude and frequency of the generator terminal voltage and the grid connection state;

[0251] In the embodiment of the present application, the false power-on protection criteria include: Criterion 1: the machine-side current I g >I Set1 , I Set1 It is the first current action setting; Criterion 2: High voltage side current I h >I Set2 , or the sum of the currents I of switch 1 and switch 2 on the high voltage side of the main transformer h1 +I h2 >I Set2 , I Set2 is the second current action setting; Criterion 3: Generator terminal voltage U g <U Set , U Set It is the low voltage action setting value; Judgment 4: Machine end frequency F g <F Set , F Set It is the low frequency action setting value; Criterion 5: the unit is not connected to the grid, and the grid connection state is normal; Criterion 6: the unit is not connected to the grid, and the grid connection state is abnormal; Criterion 7: the unit is not connected to the grid, and the grid connection state is normal; Criterion 8: the unit is not connected to the grid, and the grid connection state is abnormal;

[0252] In the embodiment of the present application, the criteria for whether the grid-connected status is normal or abnormal include criteria 5, 6, 7, and 8, which can be automatically generated by judging the generator end current, the main transformer high-voltage side current, and the grid-connected status through logical judgment rules.

[0253] In the embodiment of the present application, the result determination module includes starting the false power-on protection action logic based on the false power-on protection criterion through the combination of the criterion to form a false power-on protection scheme.

[0254] In an embodiment of the present application, the protection criteria can be combined to meet the incorrect power-on protection action conditions and start the incorrect power-on protection action logic, including combination 1: criterion 1, criterion 2, criterion 3, and criterion 6 are met at the same time; combination 2: criterion 1, criterion 2, criterion 4, and criterion 6 are met at the same time; combination 3: criterion 1, criterion 2, and criterion 5 are met at the same time; combination 4: criterion 1, criterion 2, criterion 3, and criterion 5 are met at the same time; combination 5: criterion 1, criterion 2, criterion 4, and criterion 5 are met at the same time; combination 6: criterion 1, criterion 2, criterion 3, criterion 4, and criterion 5 are met at the same time; combination 7: criterion 1, criterion 2, criterion 3, criterion 4, and criterion 6 are met at the same time.

[0255] In the embodiment of the present application, criterion 3 or criterion 4 is satisfied after delay T1, and the delay is widened by T2 after the criterion is returned; criterion 5 is satisfied after delay T3, and the delay is widened by T4 after the criterion is returned; criterion 6 is satisfied after delay T3, and criterion 5 is locked; criterion 7 or criterion 8 is satisfied after delay T4, and the false power-on protection is locked; after the false power-on protection criterion is satisfied, it acts on sending a signal or acting on the export after a delay of T5.

[0256] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for protecting against false power-on based on grid-connected status, characterized in that: include: Collect the generator terminal current, main transformer high voltage side current, generator terminal voltage amplitude and frequency and grid connection status; Use overcurrent components, low-frequency and low-voltage components, and grid-connected status components to pre-process the collected data and determine whether the grid-connected status is abnormal; If the grid-connected state is abnormal, an abnormal grid-connected state alarm is issued and the grid-connected state judgment criteria are exited; If the grid-connected state is normal, the system will determine whether the generator has been connected to the grid based on the grid-connected state judgment rule and the current auxiliary judgment criterion. If it has been connected to the grid, the system will automatically exit the false power-on protection; if it has not been connected to the grid, the system will automatically enter the false power-on protection. Design the false power-on protection criterion based on the generator terminal current, the main transformer high-voltage side current, the amplitude and frequency of the generator terminal voltage and the grid connection status; Based on the false power-on protection criterion, the false power-on protection action logic is started through the combination of the criterion to form a false power-on protection scheme.

2. The method for protecting against wrong power-on based on the grid-connected state according to claim 1, characterized in that: The grid connection status includes the following rules: If there is no circuit breaker at the generator end, it is considered that the generator end is connected to the low-voltage side of the main transformer; If the machine-side circuit breaker is closed and the generator-side current I g ≥I LowVal1 , it is considered that the generator end is connected to the low-voltage side of the main transformer; If the machine-side current I g ≥I LowVal2 , it is considered that the generator end is connected to the low-voltage side of the main transformer; If there is no high-voltage side switch 1 and no high-voltage side switch 2, it is considered that the main transformer is connected to the main grid; If the high-voltage side switch 1 is closed and the high-voltage side current of the main transformer I h ≥I LowVal3 , then the main transformer is considered to be connected to the main grid; If the high-voltage side switch 1 is closed and the sum of the currents I h1 +I h2 ≥I LowVal3 , then the main transformer is considered to be connected to the main grid; If the high-voltage side switch 2 is closed and the high-voltage side current I h ≥I LowVal3 , then the main transformer is considered to be connected to the main grid; If the high-voltage side switch 2 is closed and the sum of the currents I h1 +I h2 ≥I LowVal3 , then the main transformer is considered to be connected to the main grid; If the high voltage side current of the main transformer I h ≥I LowVal4 , then the main transformer is considered to be connected to the main grid; If the sum of the currents of switch 1 and switch 2 on the high-voltage side of the main transformer is h1 +I h2 ≥I LowVal4 , then the main transformer is considered to be connected to the main grid; If the generator end is connected to the low-voltage side of the main transformer, and the main transformer is connected to the main grid, it means grid connection, and the grid connection status is 1; If the generator end is not connected to the low-voltage side of the main transformer, it means that it is not connected to the grid, and the grid connection status is 0; If the main transformer is not connected to the main grid, it means that it is not connected to the grid, and the grid connection status is 0; Among them, I LowVal1 is the first current threshold, I LowVa;2 is the second current threshold, I LowVal3 is the third current threshold, I LowVal4 It is the fourth current threshold.

3. The method for protecting against wrong power-on based on the grid-connected state according to claim 1 or 2, characterized in that: The determination of whether the grid-connected state is abnormal includes the following rules: If the grid-connected state is 0 and the machine-end current I g ≥I LowVal5 And the main transformer high voltage side current I h ≥I LowVal6 , it is judged that the grid-connected state is abnormal; If the grid-connected state is 0 and the machine-end current I g ≥I LowVal5 And the sum of the currents of switch 1 and switch 2 on the high side is I h1 +I h 2≥I LowVal6 , it is judged that the grid-connected state is abnormal; If the grid-connected state is 1 and the machine-end current I g LowVal5 , it is judged that the grid-connected state is abnormal;​ If the grid-connected state is 1 and the high-voltage side current of the main transformer I h LowVal6 , it is judged that the grid-connected state is abnormal;​ If the grid connection state is 1 and the sum current of switch 1 and switch 2 on the high side is I h1 +I h2 LowVal6 , it is judged that the grid-connected state is abnormal;​ Among them, I LowVal5 is the fifth current threshold, I LowVal6 It is the sixth current threshold.

4. The method for protecting against wrong power-on based on the grid-connected state according to claim 3, characterized in that: The method of determining whether the generator has been connected to the grid includes the following rules: If the grid-connected state is 0, the machine-end current I g ≥I LowVal5 And the main transformer high voltage side current I h ≥I LowVal6 , the unit has been connected to the grid, and the error power-on protection has stopped operation; If the grid-connected state is 0, the machine-end current I g ≥I LowVal5 And the sum of the currents of switch 1 and switch 2 on the high side is I h1 +I h 2≥I LowVal6 , the unit has been connected to the grid, and the error power-on protection has stopped operation; If the grid-connected state is 1, the machine-end current I g ≥I LowVal5 And the main transformer high voltage side current I h ≥I LowVal6 , the unit has been connected to the grid, and the error power-on protection has stopped operation; If the grid-connected state is 1, the machine-end current I g ≥I LowVal5 And the sum of the currents of switch 1 and switch 2 on the high side is I h1 +I h 2≥I LowVal6 , the unit has been connected to the grid, and the error power-on protection has stopped operation; If the grid-connected state is 0, the machine-end current I g LowVal5 , the unit is not connected to the grid, and the false power-on protection is put into operation;​ If the grid-connected state is 0, the high-voltage side current of the main transformer I h LowVal6 , the unit is not connected to the grid, and the false power-on protection is put into operation;​ If the grid-connected state is 0, the sum current of switch 1 and switch 2 on the high-voltage side I h1 +I h2 LowVal6 , the unit is not connected to the grid, and the false power-on protection is put into operation;​ If the grid-connected state is 1, the machine-end current I g LowVal5 , the unit is not connected to the grid, and the false power-on protection is put into operation;​ If the grid-connected state is 1, the high-voltage side current of the main transformer I h LowVal6 , the unit is not connected to the grid, and the false power-on protection is put into operation;​ If the grid connection state is 1 and the sum current of switch 1 and switch 2 on the high side is I h1 +I h2 LowVal6 , the unit is not connected to the grid and the error power-on protection is put into operation.​ 5. The method for protecting against wrong power-on based on the grid-connected state according to claim 4, characterized in that: The designed erroneous power-on protection criterion includes a first criterion, a second criterion, a third criterion, a fourth criterion, a fifth criterion, a sixth criterion, a seventh criterion, and an eighth criterion; The first criterion is the machine-end current I g >I Set1 , I Set1 It is the first current action setting; The second criterion is the high voltage side current I of the main transformer h >I Set2 , or the sum of the currents I of switch 1 and switch 2 on the high voltage side of the main transformer h1 +I h2 >I set2 , I set2 It is the second current action setting; The third criterion is the generator terminal voltage U g Set , U Set It is the low voltage action setting value;​ The fourth criterion is the terminal frequency F g <F Set , F Set Set value for low frequency action; The fifth criterion is that the unit is not connected to the grid and the grid connection status is normal; The sixth criterion is that the unit is not connected to the grid and the grid connection state is abnormal; The seventh criterion is that the unit has been connected to the grid and the grid connection status is normal; The eighth criterion is that the unit has been connected to the grid and the grid connection status is abnormal.

6. The method for protecting against wrong power-on based on the grid-connected state according to claim 5, characterized in that: The combination of criteria for starting the false power-on protection action logic includes a first combination, a second combination, a third combination, a fourth combination, a fifth combination, a sixth combination and a seventh combination; If any combination is met, the false power-on protection action logic is activated; The first combination includes simultaneously satisfying the first criterion, the second criterion, the third criterion and the sixth criterion; The second combination includes satisfying the first criterion, the second criterion, the fourth criterion and the sixth criterion at the same time; The third combination includes satisfying the first criterion, the second criterion and the fifth criterion at the same time; The fourth combination includes satisfying the first criterion, the second criterion, the third criterion and the fifth criterion at the same time; The fifth combination includes satisfying the first criterion, the second criterion, the fourth criterion and the fifth criterion at the same time; The sixth combination includes satisfying the first criterion, the second criterion, the third criterion, the fourth criterion and the fifth criterion at the same time; The seventh combination includes satisfying the first criterion, the second criterion, the third criterion, the fourth criterion and the sixth criterion at the same time; When the duration of the third criterion exceeds T1, the third criterion is considered to be established; When the duration of the fourth criterion exceeds T1, the fourth criterion is considered to be established; When the duration of the third criterion exceeds T2, it is considered that the third criterion returns; When the duration of the fourth criterion exceeds T2, it is considered that the fourth criterion returns; When the fifth criterion lasts longer than T3, the fifth criterion is considered to be established; When the duration of the sixth criterion exceeds T3, the sixth criterion is considered to be established and the fifth criterion is locked; When the fifth criterion lasts longer than T4, it is considered that the fifth criterion has returned; When the duration of the seventh criterion exceeds T4, the seventh criterion is considered to be established and the false power-on protection is locked; When the duration of the eighth criterion exceeds T4, the eighth criterion is considered to be established and the false power-on protection is locked; When all the combinations of false power-on criteria are met and the system waiting time exceeds T5, it is considered that the false power-on protection is activated and the protection action is executed.

7. The method for protecting against wrong power-on based on the grid-connected state according to claim 6, characterized in that: The fifth criterion includes the following rules: If the grid-connected state is 0, the machine-end current I g LowVal5 And the main transformer high voltage side current I h LowVal6 , the unit is not connected to the grid, and the grid connection status is normal;​​ If the grid-connected state is 0, the machine-end current I g LowVal5 And the sum of the currents of switch 1 and switch 2 on the high side is I h1 +I h2 LowVal6 , the unit is not connected to the grid, and the grid connection status is normal;​​ The sixth criterion includes the following rules: If the grid-connected state is 0 and the machine-end current I g ≥I LowVal5 , the unit is not connected to the grid and the grid connection status is abnormal; If the grid-connected state is 0 and the high-voltage side current I h ≥I LowVal6 , the unit is not connected to the grid and the grid connection status is abnormal; If the grid-connected state is 0 and the sum of the currents of switch 1 and switch 2 on the high-voltage side is I h1 +I h2 ≥I LowVal6 , the unit is not connected to the grid and the grid connection status is abnormal; The seventh criterion includes the following rules: If the grid-connected state is 1, the machine-end current I g ≥I LowVal5 And the main transformer high voltage side current I h ≥I LowVal6 , the unit has been connected to the grid and the grid connection status is normal; If the grid-connected state is 1, the machine-end current I g ≥I LowVal5 And the sum of the currents of switch 1 and switch 2 on the high side is I h1 +I h2 ≥I LowVal6 , the unit has been connected to the grid and the grid connection status is normal; The eighth criterion includes the following rules: If the grid-connected state is 1 and the machine-end current I g LowVal5 , the unit has been connected to the grid, and the grid connection status is abnormal;​ If the grid-connected state is 1 and the high-voltage side current of the main transformer I h LowVal6 , the unit has been connected to the grid, and the grid connection status is abnormal;​ If the grid connection state is 1 and the sum current of switch 1 and switch 2 on the high side is I h1 +I h2 LowVal6 , the unit has been connected to the grid, and the grid connection status is abnormal.​ 8. A system based on the grid-connected state-based false power-on protection method according to claim 1, characterized in that: The acquisition module is used to collect the generator terminal current, the main transformer high-voltage side current, the generator terminal voltage amplitude and frequency and the grid-connected status; The abnormality identification module is used to pre-process the collected data using overcurrent components, low-frequency and low-voltage components, and grid-connected status components to determine whether the grid-connected status is abnormal; The first abnormal module is used to issue an abnormal grid state alarm and exit the grid state judgment if the grid state is abnormal; The second abnormal module is used to determine whether the generator has been connected to the grid according to the grid state determination rule and the current auxiliary determination criterion if the grid-connected state is normal. If it has been connected to the grid, it will automatically exit the false power-on protection; if it has not been connected to the grid, it will automatically enter the false power-on protection; A design module for designing the false power-on protection criterion based on the generator terminal current, the main transformer high-voltage side current, the amplitude and frequency of the generator terminal voltage, and the grid connection status; The result judgment module is used to start the false power-on protection action logic based on the false power-on protection judgment criterion through the combination of judgment criteria to form a false power-on protection scheme.

9. An electronic device, characterized in that: include: Memory, used to store programs; A processor is used to load the program to execute the steps of the grid-connected state-based false power-on protection method as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a program, characterized in that: When the program is executed by the processor, the steps of the grid-connected state-based false power-on protection method as described in any one of claims 1 to 7 are implemented.

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