A power grid feeder protection method and primary and secondary integrated distribution terminal

Abstract

The present invention relates to the technical field of power grid feeder protection, and specifically, to a power grid feeder protection method and a primary and secondary integrated distribution terminal. It includes the following method steps: S1, obtaining multiple renewable energy power generation systems around the power supply range of the feeder, and respectively incorporating the multiple renewable energy power generation systems into different positions of the feeder; S2, monitoring the operating status of each circuit breaker in the feeder, and obtaining the fault area of ​​the feeder in real time; in the power grid feeder protection method and the primary and secondary integrated distribution terminal, the fault area in the feeder is detected by the renewable energy power generation system, and the reason for the tripping of the circuit breaker in the feeder is obtained, so that the tripped circuit breaker in the feeder can be operated according to the reason, so that the feeder can be reclosed in time when a transient fault occurs; when a permanent fault occurs in the feeder, the phenomenon of reclosing of the circuit breaker on the feeder is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid feeder protection, and in particular to a power grid feeder protection method applied to a primary-secondary integrated power distribution terminal and a primary-secondary integrated power distribution terminal. Background Art

[0002] A feeder in a power grid refers to a branch connected to any node in a distribution network, which can be an infeed branch or an outfeed branch. The main function of these branches is to transmit electrical energy, and due to the typical radial topology of the distribution network, the energy flow is usually unidirectional. However, in order to improve the reliability of power supply, the distribution network structure has become complex, resulting in the power transmission direction not being absolutely single. Therefore, it can be roughly said that any branch in a distribution network can be regarded as a feeder.

[0003] The intelligent feeder distribution terminal is distributed at various locations of the feeder, and is generally composed of a control part, a data processing part, and a communication part. The control part: energy storage, closing operation, and opening operation of the circuit breaker; the data processing part: integrated FTU, relying on FTU to complete data collection and processing; the communication part: integrated communication module, 4G wireless communication, optical fiber communication, etc.

[0004] Intelligent feeder distribution terminals generally have three remote functions: telemetry, remote control, and remote signaling (some terminals integrate remote adjustment functions). Through FTU, the automatic protection function of the line can be realized, and the status of the circuit breaker and the feeder operation status can be monitored in real time.

[0005] However, when a feeder fails, there are usually two reasons for the failure. One is a transient failure, such as high-load power transmission during peak hours, bird damage, lightning strikes, strong winds, etc.; the other is a permanent failure, such as a feeder short circuit or disconnection.

[0006] At present, most faults are judged by reclosing, that is, when the circuit breaker trips, the circuit breaker is controlled to reclose, and the circuit breaker no longer trips, indicating that the fault has been repaired. However, when a short circuit occurs in the feeder, frequent reclosing of the circuit breaker will cause the feeder to be hit by the short-circuit current again, making the working conditions of the circuit breaker worse. Summary of the invention

[0007] The object of the present invention is to provide a power grid feeder protection method and a primary-secondary integrated power distribution terminal to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above object, one of the objects of the present invention is to provide a power grid feeder protection method, comprising the following method steps:

[0009] S1. Acquire multiple renewable energy power generation systems around the power supply range of the feeder, and respectively integrate the multiple renewable energy power generation systems into different positions of the feeder;

[0010] S2. Monitor the operating status of each circuit breaker in the feeder and obtain the fault area of ​​the feeder in real time;

[0011] S3. When a feeder fails, the power of the renewable energy power generation system in the fault area is transmitted to the fault area after voltage reduction;

[0012] S4. Monitor the operating status of the circuit breaker between the renewable energy power generation system and the feeder in real time, and selectively reclose the tripped circuit breaker in the feeder according to the operating status.

[0013] As a further improvement of the technical solution, the method steps of incorporating the plurality of renewable energy power generation systems at different positions of the feeder in S1 are as follows:

[0014] S1.1. Determine the power supply range based on the direction of the feeder;

[0015] S1.2. Multiple access points are arranged on the feeder in an equidistant manner, and the number of the access points is at least two;

[0016] S1.3. Find a renewable energy power generation system around the power supply range, and connect the transmission end of the renewable energy power generation system to the access point on the feeder after connecting the circuit breaker;

[0017] S1.4. Under normal conditions, the circuit breaker is in the open state.

[0018] As a further improvement of the present technical solution, the renewable energy power generation system in S1 is a solar power generation system or a wind power generation system.

[0019] As a further improvement of the technical solution, the method steps for obtaining the fault area of ​​the feeder in real time in S2 are as follows:

[0020] S2.1. Remotely connect to each circuit breaker in the feeder to obtain the tripping status of the circuit breaker;

[0021] S2.2. When a circuit breaker on a feeder line trips, the power supply area behind the circuit breaker is marked as a fault area.

[0022] As a further improvement of the technical solution, the method steps for transmitting power to the fault area in S3 are as follows:

[0023] S3.1. Establishing a connection with a circuit breaker at the transmission end of a renewable energy power generation system to achieve remote control of the circuit breaker;

[0024] S3.2, obtaining a connection point corresponding to the fault area, and querying a renewable energy power generation system corresponding to the connection point;

[0025] S3.3, reducing the voltage at the transmission end of the renewable energy power generation system in S3.2, so that the voltage at the transmission end of the renewable energy power generation system is lower than the voltage of the feeder;

[0026] S3.4. Reduce the tripping threshold of the circuit breaker at the transmission end of the renewable energy generation system;

[0027] S3.5, controlling the circuit breaker at the transmission end of the renewable energy power generation system in S3.2 to close, so that the power of the renewable energy power generation system is transmitted to the feeder where the fault occurs.

[0028] As a further improvement of the technical solution, the method steps of selectively reclosing the tripped circuit breaker in the feeder in S4 are as follows:

[0029] S4.1. Generate feedback information based on the operating status of the circuit breaker at the transmission end of the renewable energy power generation system, wherein the feedback information includes a tripping state and a non-tripping state;

[0030] S4.2, when the feedback information is in a non-tripping state, the circuit breaker at the transmission end of the renewable energy power generation system is controlled to trip, and the tripped circuit breaker on the feeder is controlled to reclose;

[0031] S4.3. When the feedback information is in the tripping state, stop reclosing the tripped circuit breaker on the feeder.

[0032] As a further improvement of this technical solution, the following method steps are also included:

[0033] S4.4, when the feedback information is in the tripping state, the circuit breakers on the feeders corresponding to the fault area are closed in sequence until the feedback information is in the non-tripping state, thereby determining the normal line in the fault area;

[0034] S4.5. Restore the voltage at the transmission end of the renewable energy power generation system and the tripping threshold of the circuit breaker so that the renewable energy power generation system can supply power to the normal line.

[0035] The second object of the present invention is to provide a primary-secondary integrated distribution terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the power grid feeder protection method as one of the above-mentioned objects are implemented.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. In the power grid feeder protection method and the primary and secondary integrated distribution terminal, the fault area in the feeder is detected by the renewable energy power generation system to obtain the reason for the tripping of the circuit breaker in the feeder, so that the tripped circuit breaker in the feeder can be operated according to the reason, so that the feeder can be reclosed in time when a transient fault occurs; when a permanent fault occurs in the feeder, the circuit breaker on the feeder is prevented from reclosing.

[0038] 2. In the grid feeder protection method and the primary and secondary integrated distribution terminal, the voltage of the renewable energy power generation system is reduced. In this way, when the power of the renewable energy power generation system is transmitted to the feeder, if the feeder is in a short-circuit state, the circuit breaker at the transmission end of the renewable energy power generation system will trip. However, because the voltage of the renewable energy power generation system is reduced, the energy caused by the short circuit is reduced. At this time, the circuit breaker at the transmission end of the renewable energy power generation system will be less affected.

[0039] 3. In the grid feeder protection method and the primary and secondary integrated distribution terminal, the renewable energy power generation system can not only analyze the cause of the feeder failure, but also check the faulty part of the feeder in the process of reducing the voltage, so that the power of the renewable energy power generation system can bypass the faulty part and transmit power to the feeder behind the faulty part, so as to further improve the power supply efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the overall workflow of the present invention;

[0041] Figure 2 It is a schematic diagram of the overall method flow of the present invention;

[0042] Figure 3 A schematic flow chart of a method of incorporating the renewable energy power generation system of the present invention into different positions of the feeder line;

[0043] Figure 4 A schematic flow chart of a method for obtaining a fault area of ​​a feeder in real time according to the present invention;

[0044] Figure 5 It is a schematic flow chart of a method for transmitting electric power to the fault area according to the present invention;

[0045] Figure 6 The present invention is a flow chart of a method for reclosing a tripped circuit breaker in a feeder. DETAILED DESCRIPTION

[0046] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0048] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0049] See also Figure 1-Figure 6 As shown, one of the purposes of the present invention is to provide a power grid feeder protection method, comprising the following method steps:

[0050] S1. Acquire multiple renewable energy power generation systems around the power supply range of the feeder, and respectively integrate the multiple renewable energy power generation systems into different positions of the feeder;

[0051] S2, monitor the operating status of each circuit breaker in the feeder and obtain the fault area of ​​the feeder in real time;

[0052] S3. When a feeder fails, the power of the renewable energy power generation system in the fault area is transmitted to the fault area after voltage reduction;

[0053] S4. Monitor the operating status of the circuit breaker between the renewable energy power generation system and the feeder in real time, and selectively reclose the tripped circuit breaker in the feeder according to the operating status.

[0054] That is to say, by detecting the faulty area in the feeder through the renewable energy power generation system, the reason for the tripping of the circuit breaker in the feeder can be obtained, so that the tripped circuit breaker in the feeder can be operated according to the reason, so that the feeder can be reclosed in time when a transient fault occurs; when a permanent fault occurs in the feeder, the reclosing of the circuit breaker on the feeder can be avoided.

[0055] Among them, the renewable energy power generation system is a solar power generation system or a wind power generation system.

[0056] In addition, the method steps for integrating multiple renewable energy generation systems at different positions of the feeder in S1 are as follows:

[0057] S1.1. Determine the power supply range based on the direction of the feeder;

[0058] S1.2. Multiple access points are set on the feeder in an equidistant manner, and there are at least two access points;

[0059] S1.3. Find a renewable energy power generation system around the power supply range, and connect the transmission end of the renewable energy power generation system to the access point on the feeder after connecting the circuit breaker;

[0060] S1.4. Under normal conditions, the circuit breaker is in the open state.

[0061] Specifically, for example, if the feeder is 10 km long, then access points can be set at the head and end of the feeder; or an access point can be set every 2 km (the specific number can be determined based on the actual power supply demand, and the present invention is not limited here). There are at least two access points to ensure that the renewable energy power generation system can detect the feeder behind the circuit breaker after the circuit breaker on the feeder trips, so as to understand the status of the feeder behind the circuit breaker. For example, when the circuit breaker in the middle of the feeder trips, the power at the head end of the feeder cannot be transmitted through the tripped circuit breaker. At this time, the end of the feeder is in a power-off state. When the access points are located at the head and end of the feeder, the renewable energy power generation system connected to the end of the feeder can detect the cause of the power outage at the end of the feeder.

[0062] Furthermore, the method steps for obtaining the fault area of ​​the feeder in real time in S2 are as follows:

[0063] S2.1. Remotely connect to each circuit breaker in the feeder to obtain the tripping status of the circuit breaker;

[0064] S2.2. When a circuit breaker on a feeder line trips, the power supply area behind the circuit breaker is marked as a fault area.

[0065] Specifically, for example, 10 circuit breakers are arranged in a feeder. When the 5th circuit breaker trips, the feeders corresponding to the 5th to 10th circuit breakers are all in a power-off state, and the areas corresponding to the 5th to 10th circuit breakers are all fault areas.

[0066] When the circuit breaker on the feeder trips, there are two reasons for the fault. One is a transient fault, such as high-load power transmission during peak hours, bird damage, lightning strikes, strong winds, etc. The other is a permanent fault, such as a short circuit or disconnection of the feeder. When the feeder fails due to a short circuit, if the circuit breaker on the feeder is directly controlled to close, the circuit breaker on the feeder will trip for the second time in a short time, thereby affecting the life of the circuit breaker on the feeder. To this end, the method steps for transmitting power to the fault area in S3 are as follows:

[0067] S3.1. Establishing a connection with a circuit breaker at the transmission end of a renewable energy power generation system to achieve remote control of the circuit breaker;

[0068] S3.2, obtaining a connection point corresponding to the fault area, and querying the renewable energy power generation system corresponding to the connection point;

[0069] S3.3, reducing the voltage at the transmission end of the renewable energy power generation system in S3.2, so that the voltage at the transmission end of the renewable energy power generation system is lower than the voltage of the feeder;

[0070] S3.4. Reduce the tripping threshold of the circuit breaker at the transmission end of the renewable energy generation system;

[0071] S3.5, controlling the circuit breaker at the transmission end of the renewable energy power generation system in S3.2 to close, so that the power of the renewable energy power generation system is transmitted to the feeder where the fault occurs;

[0072] In this way, when a feeder fault occurs, the circuit breaker on the feeder will not be closed first. At this time, the connection point is queried in the fault area, and the corresponding renewable energy power generation system is found through the connection point. Then, the circuit breaker at the transmission end of the renewable energy power generation system is controlled to close by remote control. At this time, the power of the renewable energy power generation system can be transmitted to the feeder.

[0073] In this process, taking the tripping of the 5th circuit breaker as an example, the connection point should be after the 5th circuit breaker, and the feeder is in two parts at this time, one part is before the 5th circuit breaker, and the other part is after the 5th circuit breaker. Due to the tripping of the 5th circuit breaker, the two parts of the feeder are in a non-conductive state. Therefore, when the renewable energy generation system transmits electricity to the feeder, the electricity is after the 5th circuit breaker, and the two parts of the electricity will not be conductive.

[0074] Furthermore, in the above-mentioned S3.3 and S3.4, by reducing the voltage of the renewable energy power generation system, when the power of the renewable energy power generation system is transmitted to the feeder, if the feeder is in a short-circuit state, the circuit breaker at the transmission end of the renewable energy power generation system will trip. However, because the voltage of the renewable energy power generation system is reduced, the energy caused by the short circuit is reduced, and the circuit breaker at the transmission end of the renewable energy power generation system will be less affected.

[0075] In addition, the method steps for selectively reclosing the tripped circuit breaker in the feeder in S4 are as follows:

[0076] S4.1. generating feedback information of the operating status of the circuit breaker at the transmission end of the renewable energy power generation system, wherein the feedback information includes a tripping state and a non-tripping state;

[0077] S4.2, when the feedback information is in a non-tripping state, the circuit breaker at the transmission end of the renewable energy power generation system is controlled to trip, and the tripped circuit breaker on the feeder is controlled to reclose;

[0078] S4.3. When the feedback information is in the tripping state, stop reclosing the tripped circuit breaker on the feeder.

[0079] That is to say, when the power of the renewable energy power generation system is transmitted to the feeder, if the feeder is in a short-circuit state, the circuit breaker at the transmission end of the renewable energy power generation system will trip, which means that the fault of the feeder is caused by a short circuit, and the reclosing of the tripped circuit breaker on the feeder will be stopped at this time; if the feeder is caused by high load, then at the moment of power failure of the feeder, the downstream electrical equipment is in a power-off state. When the power of the renewable energy power generation system is transmitted to the feeder, since most of the power-off equipment will not continue to operate, the feeder will not be in a high-load state at this time, so the circuit breaker at the transmission end of the renewable energy power generation system will not trip. This shows that the fault of the feeder is caused by high load, and the tripped circuit breaker on the feeder can be reclosed at this time. This can achieve timely restoration of power supply and avoid the circuit breaker on the feeder from being affected by secondary short circuits in a short period of time.

[0080] In addition, the method also includes the following steps:

[0081] S4.4, when the feedback information is in the tripping state, the circuit breakers on the feeders corresponding to the fault area are closed in sequence until the feedback information is in the non-tripping state, thereby determining the normal line in the fault area;

[0082] S4.5. Restore the voltage at the transmission end of the renewable energy power generation system and the tripping threshold of the circuit breaker so that the renewable energy power generation system can supply power to the normal line.

[0083] For example, if a short circuit occurs between the 5th circuit breaker and the 6th circuit breaker, the 5th circuit breaker will trip, and the feeder after the 6th circuit breaker will be a normal line. However, due to the short circuit between the 5th circuit breaker and the 6th circuit breaker, the power at the head end of the feeder cannot be transmitted to the normal line, and thus normal power transmission cannot be performed. For this reason, when the renewable energy power generation system transmits power to the feeder, the circuit breaker at the renewable energy power generation system will still trip. At this time, the 6th circuit breaker is controlled to trip, so that the connection between the 5th circuit breaker and the 6th circuit breaker is disconnected. In this way, the renewable energy power generation system will not transmit power to the short circuit, and the feeder after the 6th circuit breaker can be powered at this time.

[0084] In other words, the renewable energy power generation system can not only analyze the cause of the feeder failure, but also check the faulty part of the feeder during the process of lowering the voltage, so that the power of the renewable energy power generation system can bypass the faulty part and transmit power to the feeder behind the faulty part, so as to further improve the efficiency of power supply.

[0085] The second object of the present invention is to provide a primary-secondary integrated distribution terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the steps of the power grid feeder protection method as one of the above-mentioned objects are implemented.

[0086] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A power grid feeder protection method, characterized in that: The steps include: S1. Acquire multiple renewable energy power generation systems around the power supply range of the feeder, and respectively integrate the multiple renewable energy power generation systems into different positions of the feeder; S2. Monitor the operating status of each circuit breaker in the feeder and obtain the fault area of ​​the feeder in real time; S3. When a feeder fails, the power of the renewable energy power generation system in the fault area is transmitted to the fault area after voltage reduction; S4. Real-time monitoring of the operating status of the circuit breaker between the renewable energy power generation system and the feeder, and selectively reclosing the tripped circuit breaker in the feeder according to the operating status; The method steps of integrating the plurality of renewable energy power generation systems into different positions of the feeder in S1 are as follows: S1.

1. Determine the power supply range based on the direction of the feeder; S1.

2. Multiple access points are arranged on the feeder in an equidistant manner, and the number of the access points is at least two; S1.

3. Find a renewable energy power generation system around the power supply range, and connect the transmission end of the renewable energy power generation system to the access point on the feeder after connecting the circuit breaker; S1.4, Under normal conditions, the circuit breaker is in the open state; The method steps for obtaining the fault area of ​​the feeder in real time in S2 are as follows: S2.

1. Remotely connect to each circuit breaker in the feeder to obtain the tripping status of the circuit breaker; S2.2, when a circuit breaker on the feeder trips, the power supply area behind the circuit breaker is marked as a fault area; The method steps for transmitting power to the fault area in S3 are as follows: S3.

1. Establishing a connection with a circuit breaker at the transmission end of a renewable energy power generation system to achieve remote control of the circuit breaker; S3.2, obtaining a connection point corresponding to the fault area, and querying a renewable energy power generation system corresponding to the connection point; S3.3, reducing the voltage at the transmission end of the renewable energy power generation system in S3.2, so that the voltage at the transmission end of the renewable energy power generation system is lower than the voltage of the feeder; S3.

4. Reduce the tripping threshold of the circuit breaker at the transmission end of the renewable energy generation system; S3.5, controlling the circuit breaker at the transmission end of the renewable energy power generation system in S3.2 to close, so that the power of the renewable energy power generation system is transmitted to the feeder where the fault occurs; The method steps for selectively reclosing the tripped circuit breaker in the feeder in S4 are as follows: S4.

1. Generate feedback information based on the operating status of the circuit breaker at the transmission end of the renewable energy power generation system, wherein the feedback information includes a tripping state and a non-tripping state; S4.2, when the feedback information is in a non-tripping state, the circuit breaker at the transmission end of the renewable energy power generation system is controlled to trip, and the tripped circuit breaker on the feeder is controlled to reclose; S4.

3. When the feedback information is in the tripping state, stop reclosing the tripped circuit breaker on the feeder; S4.4, when the feedback information is in the tripping state, the circuit breakers on the feeders corresponding to the fault area are closed in sequence until the feedback information is in the non-tripping state, thereby determining the normal line in the fault area; S4.

5. Restore the voltage at the transmission end of the renewable energy power generation system and the tripping threshold of the circuit breaker so that the renewable energy power generation system can supply power to the normal line.

2. The power grid feeder protection method according to claim 1, characterized in that: The renewable energy power generation system in S1 is a solar power generation system or a wind power generation system.

3. A primary and secondary integrated power distribution terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the power grid feeder protection method as described in any one of claims 1 to 2 are implemented.

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