CN214585796U - Power grid ground fault detection system and wind power plant system - Google Patents

Abstract

The utility model discloses a grid ground fault detecting system and wind-powered electricity generation field system, wherein grid ground fault detecting system includes: at least three grid nodes; the different power grid nodes are connected through the feeder lines; the grounding module is connected with a power grid node or a feeder line; the grounding current detection module is connected with the grounding module to detect the current value of the grounding module; the feeder line current detection module is connected with all the feeder lines to detect the current value of each feeder line; the fault judgment module is connected with the grounding current detection module and generates a fault trigger signal according to the current value of the grounding module; and the identification module is respectively connected with the grounding current detection module and the fault judgment module, and can identify the faulty feeder line according to the current value of each feeder line. Which is capable of identifying the feeder that caused the ground fault and generating a corresponding identification signal.

Description

Power grid ground fault detection system and wind power plant system

Technical Field

The utility model relates to a power grid field, in particular to electric wire netting ground fault detecting system and wind-powered electricity generation field system.

Background

The power grid provides electric energy for production activities and daily work and rest of people, and is an important infrastructure system in modern life. The power grid comprises a plurality of grid nodes, such as transformer stations, power distribution stations and the like, and the grid nodes are connected through feeders to transmit electric energy. With the development of power generation technology, power stations which generate power in different ways are also incorporated into the power grid as grid nodes.

In the field of wind power generation, compared with a land wind farm, an offshore wind farm does not occupy land resources, the sea wind speed is higher, the single-machine capacity of a wind generating set of the offshore wind farm is larger, the annual utilization hours are higher, and the like, so that the wind power generation system is an important development field of wind power generation. Because the offshore wind farm is far away from the land bank, the traditional alternating current transmission scheme cannot meet the large-scale offshore wind farm electric energy output in the open sea, and the direct current transmission technology becomes a common scheme for outputting electric energy by wind power generation in the deep sea and the open sea. The distributed direct-current transmission based on the series-connection type uncontrolled converter station is used as an offshore wind power direct-current transmission scheme, so that the system cost and the operation loss are greatly reduced, and the system reliability is improved.

However, in the existing offshore wind farm system scheme, when an asymmetric ground fault occurs to a wind farm feeder, a line where the fault feeder is located cannot be effectively and reliably identified for corresponding safety processing.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides a power grid ground fault detecting system, it can discern the feeder that leads to asymmetric ground fault.

The utility model discloses still provide wind-powered electricity generation field system, it can discern the feeder that leads to wind-powered electricity generation field to produce asymmetric earth fault.

According to the utility model discloses electric wire netting ground fault detecting system of first aspect embodiment, include: at least three grid nodes; the different power grid nodes are connected through the feeder lines; a grounding module connected with the grid node or the feeder; the grounding current detection module is connected with the grounding module to detect the current value of the grounding module; the feeder line current detection module is connected with all the feeder lines to detect the current value of each feeder line; the fault judgment module is connected with the grounding current detection module and generates a fault trigger signal according to the current value of the grounding module; the identification module is respectively connected with the grounding current detection module and the fault judgment module, and can identify the faulty feeder line according to the current value of each feeder line.

According to the utility model discloses electric wire netting ground fault detecting system has following beneficial effect at least: the grounding current detection module detects the current value of the grounding module, when an asymmetric grounding fault occurs, the grounding current can be increased, therefore, the fault judgment module can judge whether the grounding fault occurs according to the current value of the grounding module, the fault judgment module outputs a fault trigger signal to the identification module when the grounding fault occurs, the identification module processes according to the current value of each feeder line, identifies the faulty feeder line and generates a corresponding identification signal to output, and other subsequent safety protection modules can execute safety processing measures on the faulty feeder line according to the identification signal, so that the stability of a power grid is maintained.

According to the utility model discloses a some embodiments, the fault diagnosis module includes threshold value trigger unit, threshold value trigger unit has preset safe threshold value, threshold value trigger unit's input with ground current detection module connects, threshold value trigger unit's output with identification module connects.

According to the utility model discloses a some embodiments, the identification module includes computational element and route selection module, the computational element with feeder current detection module connects in order to calculate every the unbalanced current value of feeder, threshold value trigger element with the route selection module is connected, the route selection module with the computational element is connected in order to be according to each the unbalanced current value of feeder produces identification signal.

According to the utility model discloses a some embodiments, the route selection module includes that the maximum value selects unit, comparing element and logic gate unit, the quantity of calculating the unit the quantity of comparing element and the quantity of logic gate unit with the quantity of feeder equals, the feeder the calculating element comparing element and logic gate unit one-to-one, the input that the unit was selected to the maximum value with the calculating element is connected, the first input of comparing element with correspond the calculating element is connected, the second input of comparing element with the unit connection is selected to the maximum value, logic gate unit respectively with correspond comparing element's output and threshold value trigger unit connects.

According to the utility model discloses a some embodiments, route selection module still includes the filtering unit, the quantity of filtering unit with the quantity of calculating unit equals and the one-to-one, the input of filtering unit with correspond the calculating unit is connected, the output of filtering unit with the unit is selected to the maximum value and/or the comparing unit is connected.

According to some embodiments of the utility model, still include the timing trigger unit, the quantity of timing trigger unit with the quantity of logic gate unit equals and the logic gate unit with the timing trigger unit one-to-one is connected.

According to the utility model discloses wind-powered electricity generation field system of second aspect embodiment, including foretell electric wire netting ground fault detecting system, at least one the electric wire netting node is aerogenerator.

According to the utility model discloses wind-powered electricity generation field system has following beneficial effect at least: in a wind point field, a wind driven generator is used as a power grid node and connected with other power grid nodes through a feeder line to output electric energy, the grounding current detection module is used for detecting the current value of the grounding module, whether a grounding fault occurs or not can be judged according to the current value of the grounding module, and when the grounding fault occurs, a fault lead can be identified according to the current value of each feeder line through the identification module, so that subsequent safety processing is facilitated, the effect of effectively and reliably identifying the fault feeder line when the grounding fault occurs in the wind power plant is realized, and the stability and the reliability of a wind power plant system are maintained.

According to some embodiments of the utility model, at least one the electric wire netting node is the rectifier, at least one the electric wire netting node is the dc-to-ac converter, at least one the electric wire netting node is auxiliary power source, still includes transmission cable, aerogenerator through with the rectifier is connected, the rectifier passes through transmission cable with the inverter is connected, the inverter can be connected with external electric wire netting, auxiliary power source with aerogenerator connects.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a block diagram of one embodiment of the present invention;

fig. 2 is a block diagram of another embodiment of the present invention;

FIG. 3 is a block diagram of a wind farm system according to an embodiment of the present invention;

fig. 4 is a flowchart of one embodiment of the detection method of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated with respect to the orientation description, such as up, down, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, if there are first and second descriptions for distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the precedence of the indicated technical features.

In the description of the present invention, unless there is an explicit limitation, the words such as setting, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in combination with the specific contents of the technical solution.

As shown in fig. 1 to 3, the power grid ground fault detection system according to the embodiment of the present invention includes: at least three grid nodes 100; at least two feeders 200, different grid nodes 100 are connected through the feeders 200; a grounding module 300, wherein the grounding module 300 is connected with the grid node 100 or the feeder 200; a ground current detection module 400, the ground current detection module 400 being connected to the ground module 300 to detect a current value of the ground module 300; a feeder current detection module 500, the feeder current detection module 500 being connected to all the feeders 200 to detect a current value of each feeder 200; the fault judging module 600, the fault judging module 600 is connected with the grounding current detecting module 400, and the fault judging module 600 generates a fault trigger signal according to the current value of the grounding module 300; the identification module 700, the identification module 700 is respectively connected with the grounding current detection module 400 and the fault judgment module 600, and the identification module 700 can identify the faulty feeder line 200 according to the current value of each feeder line 200.

The grounding current detection module 400 detects a current value of the grounding module 300, when an asymmetric grounding fault occurs, the grounding current increases, so the fault judgment module 600 can judge whether the grounding fault occurs according to the current value of the grounding module 300, when the grounding fault occurs, the fault judgment module 600 outputs a fault trigger signal to the identification module 700, the identification module 700 processes according to the current value of each feeder line 200, identifies the faulty feeder line 200 and generates a corresponding identification signal to output, which is beneficial for other subsequent safety protection modules to safely process the faulty feeder line 200 according to the identification signal, thereby maintaining the stability of the power grid.

The grid node 100 may be a grid device or a grid apparatus such as a transformer substation or a distribution substation. The grounding module 300 may be an embodiment including a grounding transformer, to which the grid node 100 or the feeder 200 is connected to achieve the effect of system grounding; the grounding module 300 may also include other common grid grounding devices or apparatus. When the grounding module 300 includes one grounding transformer, a neutral-to-ground current of the grounding transformer is detected as a grounding current; when the grounding module 300 includes a plurality of grounding transformers, the sum of neutral-to-ground currents of the respective grounding transformers is calculated as a grounding current.

The ground current detection module 400 may be an embodiment of a device or a circuit having a current detection function, including a current transformer or a commonly used current detection circuit. The feeder current detection module 500 may be an embodiment of a device or circuit having a current detection function, including a current transformer or a commonly used current detection circuit.

Referring to fig. 1 and 2, in some embodiments of the present invention, the failure determination module 600 includes a threshold triggering unit 610, a safety threshold is preset in the threshold triggering unit 610, an input end of the threshold triggering unit 610 is connected to the ground current detection module 400, and an output end of the threshold triggering unit 610 is connected to the identification module 700.

The grounding current detection module 400 transmits the detected current value of the grounding module 300 to the threshold trigger unit 610, and the threshold trigger unit 610 determines that a grounding fault occurs when the current value of the grounding module 300 is greater than the preset safety threshold according to the current value of the grounding module 300 and the preset safety threshold, and the threshold trigger unit 610 outputs a fault trigger signal to the identification unit so as to enable the identification unit to perform identification processing to generate an identification signal. The threshold trigger unit 610 has a simple structure and is easy to implement.

The threshold triggering unit 610 may be an embodiment including an operational amplifier, a first input terminal of the operational amplifier is connected to the ground current detection module 400, a second input terminal of the operational amplifier is connected to the reference voltage, and an output terminal of the operational amplifier is connected to the identification module 700, so that when the current value of the grounding module 300 is greater than the reference voltage, the operational amplifier changes the output level, that is, the effect of outputting the fault trigger signal is achieved, and in addition, the corresponding safety threshold can be set by adjusting the magnitude of the reference voltage. The threshold trigger unit 610 may also include a common comparison circuit.

Referring to fig. 1 and 2, in some embodiments of the present invention, the identification module 700 includes a calculation unit 710 and a line selection module 720, the calculation unit 710 is connected to the feeder current detection module 500 to calculate an unbalanced current value of each feeder 200, the threshold trigger unit 610 is connected to the line selection module 720, and the line selection module 720 is connected to the calculation unit 710 to generate an identification signal according to the unbalanced current value of each feeder 200.

Because the unbalanced current of the faulty feeder line 200 increases when an asymmetric ground fault occurs, the unbalanced current value of each feeder line 200 is calculated by the calculation unit 710, and then the line selection module 720 determines, after receiving the fault trigger signal generated by the threshold trigger unit 610, to select the feeder line 200 with the largest unbalanced current value as the faulty feeder line 200, and generates a corresponding identification signal according to the selected feeder line 200, so that other subsequent safety protection modules can know and locate the faulty feeder line 200 according to the identification signal, and further perform corresponding safety processing measures on the faulty feeder line 200. Therefore, when the ground fault occurs, the faulty feeder line 200 can be quickly and effectively identified, and the overall reliability and safety of the power grid can be improved.

The calculating unit 710 obtains the real-time values of the three-phase currents obtained by the feeder 200 detected by the feeder 200 current detecting unit, calculates the average value of the three-phase currents, and takes the absolute value of the value, namely the unbalanced current value. The calculating unit 710 may be an implementation manner including an analog-to-digital conversion circuit and a processor such as a single chip or an embedded chip, where the analog-to-digital conversion circuit converts an analog signal detected by the feeder line 200 current detecting unit into a digital signal and transmits the digital signal to the processor, and the processor calculates an unbalanced current value. The calculating unit 710 may also be an embodiment including a conventional average calculating circuit. The level output by the threshold trigger unit 610 can be used as a ground fault flag bit to facilitate subsequent safety prompt and processing.

Referring to fig. 1 and 2, in some embodiments of the present invention, the line selection module 720 includes a maximum value selection unit 721, a comparison unit 722 and a logic gate unit 723, the number of the calculation units 710, the number of the comparison units 722 and the number of the logic gate units 723 are equal to the number of the feeder lines 200, the calculation units 710, the comparison units 722 and the logic gate units 723 are in one-to-one correspondence, an input end of the maximum value selection unit 721 is connected to the calculation unit 710, a first input end of the comparison unit 722 is connected to the corresponding calculation unit 710, a second input end of the comparison unit 722 is connected to the maximum value selection unit 721, and the logic gate units 723 are respectively connected to an output end of the corresponding comparison unit 722 and the threshold trigger unit 610.

The maximum value selecting unit 721 selects the maximum unbalanced current value output by the calculating unit 710, then the comparing unit 722 corresponding to each feeder line 200 compares the unbalanced current output by the corresponding calculating unit 710 with the maximum unbalanced current value, the comparing unit 722 outputs a level to the corresponding logic gate unit 723 according to the comparison result, and the logic gate unit 723 outputs a high level only when the output level of the comparing unit 722 and the output level of the threshold starting unit satisfy a condition. For example, the logic gate units 723 are and gate devices, when the comparison result of the comparison unit 722 is that the unbalanced current value output by the calculation unit 710 is greater than or equal to the maximum unbalanced current value, the comparison unit 722 outputs a high level, and the fault trigger signal generated by the threshold trigger unit 610 is a high level, at this time, the logic gate unit 723 corresponding to the feeder 200 with the maximum unbalanced current value in the plurality of logic gate units 723 outputs a high level, so that the feeder 200 with the fault can be identified and located. With the structure, the feeder line 200 function of identifying faults can be realized without devices with complex functions, and the implementation is convenient.

The maximum value selecting unit 721 may be an embodiment including a device having a numerical processing capability, such as a single chip or an embedded chip. The comparing unit 722 may be an embodiment including an operational amplifier, a first input terminal of the operational amplifier is connected to the corresponding calculating unit 710, a second input terminal of the operational amplifier is connected to the maximum selecting unit 721, and an output terminal of the operational amplifier is connected to the logic gate; the comparison unit 722 may also be an implementation of a common comparison circuit. The logic gate unit 723 may be an embodiment including a device or circuit capable of implementing a logic gate function, such as an and gate device, or a gate device, to output an identification signal when the output level of the comparison unit 722 and the output level of the threshold triggering unit 610 satisfy a condition.

Referring to fig. 2, in some embodiments of the present invention, the line selection module 720 further includes a filtering unit 724, the number of the filtering units 724 is equal to the number of the computing units 710 and corresponds to one another, the input end of the filtering unit 724 is connected to the corresponding computing unit 710, and the output end of the filtering unit 724 is connected to the maximum value selecting unit 721 and/or the comparing unit 722.

Short-time fluctuations may occur due to disturbance of the current of the feeder 200 in the grid, resulting in unstable unbalanced currents of the feeder 200. In contrast, the filter unit 724 is arranged to filter the unbalanced current value signal of the feeder line 200 output by the calculation unit 710, so that the unbalanced current value signal is more stable, the generation of a corresponding identification signal due to false triggering caused by current disturbance of the feeder line 200 is avoided, and the improvement of reliability is facilitated.

The filtering unit 724 may be an embodiment of a device or circuit including a filter or a common filtering circuit.

Referring to fig. 1 and 2, in some embodiments of the present invention, the timing trigger unit 800 is further included, the number of the timing trigger units 800 is equal to the number of the logic gate units 723, and the logic gate units 723 are connected to the timing trigger units 800 in a one-to-one correspondence manner.

Since the asymmetrical ground fault may be caused by moisture, rainy weather, etc., a temporary asymmetrical ground fault caused by the reason may be self-repaired, and the system may operate for a short time when the asymmetrical ground fault occurs. Therefore, by providing the timing trigger unit 800, after the logic gate unit 723 outputs the identification signal to the timing trigger unit 800, the timing trigger unit 800 outputs the identification signal after a preset waiting time, so that the ground fault which can be repaired by itself temporarily can be shielded, and a safety measure is not required to be executed immediately when the ground fault occurs each time, which is beneficial to saving system resources and improving the action efficiency.

The timing trigger unit 800 may be an embodiment of a device or a circuit having a timing function, such as a timer or a timing circuit.

Referring to fig. 3, a wind farm system according to an embodiment of the second aspect of the present invention, comprising the above-mentioned grid ground fault detection system, at least one grid node 100 is a wind turbine.

In a wind point field, a wind driven generator serving as a power grid node 100 is connected with other power grid nodes 100 through feeders 200 to output electric energy, the grounding current detection module 400 is used for detecting the current value of the grounding module 300, whether a grounding fault occurs or not can be judged according to the current value of the grounding module 300, and when the grounding fault occurs, a faulty lead can be identified through the identification module 700 according to the current value of each feeder 200, so that subsequent safety processing is facilitated, the effect of effectively and reliably identifying the faulty feeder 200 when the grounding fault occurs in a wind power plant is achieved, and the stability and reliability of a wind power plant system are facilitated to be maintained.

Referring to fig. 3, in some embodiments of the present invention, at least one grid node 100 is a rectifier, at least one grid node 100 is an inverter, and at least one grid node 100 is an auxiliary power source, and further comprising a transmission cable 900, the wind turbine is connected to the rectifier through the transmission cable 900, the rectifier is connected to the inverter through the transmission cable 900, the inverter is connectable to an external power grid, and the auxiliary power source is connected to the wind turbine.

The offshore wind farm transmits electric energy to an onshore power grid through direct current transmission, so that the wind driven generator is connected with the rectifier through the feeder line 200 to convert alternating current generated by the wind driven generator into direct current, then the direct current is transmitted to the inverter through the transmission cable 900, and the inverter inverts the direct current into the alternating current and then merges the alternating current into the onshore power grid, thereby realizing the purpose of outputting the electric energy by the offshore wind farm. Meanwhile, the offshore wind power plant needs external power supply when being started, the auxiliary power supply is connected with the wind driven generator, the auxiliary power supply generates alternating current for assisting the wind driven generator in starting, and the wind driven generator enters a standby state after being started so as to support the wind driven generator to start, and the effect of assisting the wind driven generator in starting is achieved.

Referring to fig. 4, a detection method according to an embodiment of the third aspect of the present invention includes the steps of:

s1: detecting and acquiring a grounding current value and a current value of each feeder line 200;

s2: judging whether the grounding current value is greater than a preset safety threshold value, if so, executing step S3;

s3: calculating the unbalanced current value of each feeder line 200;

s4: selecting the feeder line 200 corresponding to the maximum unbalanced current value as the faulty feeder line 200 and generating a corresponding identification signal;

s5: and outputting an identification signal.

Detecting and acquiring a grounding current value, judging whether an asymmetric grounding fault occurs according to whether the grounding current value is greater than a preset safety threshold value, judging that the asymmetric grounding fault occurs when the grounding current value is greater than the preset safety threshold value, then calculating and selecting the feeder 200 corresponding to the maximum unbalanced current value as the feeder 200 causing the grounding fault according to the acquired current value of each feeder 200, and generating a corresponding identification signal according to the feeder 200 for outputting, so that the faulty feeder 200 can be conveniently positioned according to the identification signal to execute safety measures, and the stability of a power grid can be maintained.

Referring to fig. 4, in some embodiments of the present invention, after step S4, step S41 is further included: and judging whether the grounding current value is kept larger than the preset safety threshold value within the preset time and the identification signal is not changed, if so, executing S5, and if not, returning to the step S1.

Since the asymmetrical ground fault may be caused by moisture, rainy weather, etc., a temporary asymmetrical ground fault caused by the reason may be self-repaired, and the system may operate for a short time when the asymmetrical ground fault occurs. Therefore, after the grounding current is kept larger than the preset safety threshold value and the identification signal is not changed for the preset time, namely the grounding fault disappears and is automatically repaired within the preset time, the identification signal is output to execute safety measures on the faulty feeder line 200, and the grounding fault is actively repaired.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The invention is not limited to the above embodiments, and those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the invention, and such equivalent modifications or substitutions are included in the scope defined by the claims of the present application.

Claims (8)

1. Electric wire netting ground fault detection system, its characterized in that includes:

at least three grid nodes (100);

at least two feeders (200), different grid nodes (100) being connected by the feeders (200);

a grounding module (300), the grounding module (300) being connected with the grid node (100) or the feeder (200);

a ground current detection module (400), the ground current detection module (400) being connected with the ground module (300) to detect a current value of the ground module (300);

a feeder current detection module (500), said feeder current detection module (500) being connected to all of said feeders (200) to detect a current value of each of said feeders (200);

the fault judgment module (600), the fault judgment module (600) is connected with the grounding current detection module (400), and the fault judgment module (600) generates a fault trigger signal according to the current value of the grounding module (300); the identification module (700), the identification module (700) is respectively connected with the grounding current detection module (400) and the fault judgment module (600), and the identification module (700) can identify the faulty feeder line (200) according to the current value of each feeder line (200).

2. The grid ground fault detection system of claim 1, wherein: the fault judgment module (600) comprises a threshold triggering unit (610), a safety threshold is preset in the threshold triggering unit (610), the input end of the threshold triggering unit (610) is connected with the grounding current detection module (400), and the output end of the threshold triggering unit (610) is connected with the identification module (700).

3. The grid ground fault detection system of claim 2, wherein: the identification module (700) comprises a calculation unit (710) and a line selection module (720), wherein the calculation unit (710) is connected with the feeder current detection module (500) to calculate the unbalanced current value of each feeder (200), the threshold trigger unit (610) is connected with the line selection module (720), and the line selection module (720) is connected with the calculation unit (710) to generate an identification signal according to the unbalanced current value of each feeder (200).

4. The grid ground fault detection system of claim 3, wherein: the line selection module (720) comprises a maximum value selection unit (721), a comparison unit (722) and a logic gate unit (723), the number of the computing units (710), the number of the comparing units (722) and the number of the logic gate units (723) are equal to the number of the feeder lines (200), the feeder line (200), the computing unit (710), the comparing unit (722) and the logic gate unit (723) are in one-to-one correspondence, the input of the maximum value selection unit (721) is connected to the calculation unit (710), a first input of the comparison unit (722) is connected to the corresponding calculation unit (710), a second input of the comparison unit (722) is connected to the maximum value selection unit (721), the logic gate unit (723) is respectively connected with the output end of the corresponding comparison unit (722) and the threshold trigger unit (610).

5. The grid ground fault detection system of claim 4, wherein: the line selection module (720) further comprises filtering units (724), the number of the filtering units (724) is equal to the number of the computing units (710) and corresponds to one another, the input ends of the filtering units (724) are connected with the corresponding computing units (710), and the output ends of the filtering units (724) are connected with the maximum value selection unit (721) and/or the comparison unit (722).

6. The grid ground fault detection system of claim 4, wherein: the timing trigger unit (800) is further included, the number of the timing trigger units (800) is equal to that of the logic gate units (723), and the logic gate units (723) are connected with the timing trigger units (800) in a one-to-one correspondence mode.

7. Wind power plant system, its characterized in that: grid ground fault detection system comprising a grid according to any of claims 1 to 6, at least one of said grid nodes (100) being a wind generator.

8. Wind park system according to claim 7, wherein: at least one of the grid nodes (100) is a rectifier, at least one of the grid nodes (100) is an inverter, and at least one of the grid nodes (100) is an auxiliary power supply, and further comprising a transmission cable (900), the wind turbine being connected to the rectifier, the rectifier being connected to the inverter via the transmission cable (900), the inverter being connectable to an external grid, and the auxiliary power supply being connected to the wind turbine.

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