CN105896729B - Power distribution network and the method for diagnosis and isolated fault based on FTU - Google Patents

Abstract

The invention discloses an FTU-based distribution network and a method for diagnosing and isolating faults. The distribution network includes a first substation and a second substation, and a plurality of section switches are arranged between the first substation and the second substation. There is a feeder terminal device on the section switch, and the feeder terminal devices are connected in sequence. The first feeder terminal device outgoing from the first substation is connected to the main station, and the first feeder terminal device outgoing from the second substation is connected to the main station. The first substation The section switch of the first outgoing line is equipped with a circuit breaker. The feeder terminal device adjusts its operation mode in real time through the central processor according to the change of the contact point, and controls the opening and closing of the switch, that is, the fault isolation is completed through the cooperation of the line head-end switch and other section switches, and the feeder is automated. The fault diagnosis and isolation of the system are more reliable and stable, and the implementation of distribution network automation is also easier and more convenient, avoiding the tripping of the circuit breaker at the outlet of the substation and reducing the scope of power outages during faults.

Description

Distribution Network Based on FTU and Method of Diagnosing and Isolating Faults

technical field

The invention relates to the technical field of distribution network feeder automation, and more particularly relates to a feeder terminal device for preventing skipping trips.

Background technique

With the continuous improvement of urban users' requirements for power supply reliability and power quality, the power supply department pays more and more attention to distribution network feeder automation. However, due to the limitation of switch type and communication conditions, it is inevitable that the circuit breaker at the outlet of the substation will trip, resulting in a power outage for the entire outgoing line. At present, the feeder automation of the urban distribution network mainly adopts the master station centralized type, intelligent distributed type and voltage time type. The master station centralized feeder automation takes a long time to isolate the fault of the master station. Generally, the existing substation exit circuit breaker is used to trip and remove the fault, and then the switches on both sides of the fault point are separated by remote control instructions, and then the substation exit circuit breaker is reclosed to restore non-fault District power supply. Intelligent distributed feeder automation is based on point-to-point communication between devices, which can quickly isolate faults. However, if the type of section switch is a load switch, or wireless communication is used between devices, the fault can only be eliminated by tripping the circuit breaker at the substation outlet. If the communication between devices is abnormal, it will also cause the switch of the entire line to trip by mistake. Although the voltage-time feeder automation does not rely on the communication network at all, it completes fault isolation and restores power supply in non-faulty areas through the automatic reclosing of switches in sequence, but the power failure time is too long and the switches reclose repeatedly, which has a great impact on the system.

Contents of the invention

In order to solve the above-mentioned technical problems, the present invention provides an FTU-based distribution network and a fault diagnosis and isolation method for improving the control logic of the FTU, avoiding the tripping of the substation outlet short-circuit device, preventing the occurrence of leapfrog tripping, and reducing the scope of power outages.

The FTU-based distribution network includes the first substation and the second substation, and multiple section switches are arranged between the first substation and the second substation. The section switches are equipped with feeder terminal devices, and the feeder terminal devices Connect sequentially, the feeder terminal device at the first outgoing end of the first substation is connected to the main station, the first outgoing feeder terminal device of the second substation is connected to the main station, and the section switch at the first outgoing end of the first substation is equipped with a first circuit breaker , the section switch at the head end of the outgoing line of the second substation is equipped with a second circuit breaker.

In some embodiments, the feeder terminal device includes a telemetry module for collecting analog values of electrical quantities on the feeder, a remote signaling module for collecting the state of the section switch, and a remote control module for controlling the opening and closing of the section switch , the communication module used for the communication between the feeder terminal devices and the communication between the feeder terminal device and the main station, and the power supply module for supplying power to the feeder terminal device, the telemetry module, the remote signal module, the remote control module, the communication module and the power supply module respectively Connect with the central processing unit.

A method for diagnosing and isolating a fault based on an FTU distribution network, comprising the following steps:

S1: The feeder terminal device at the head end of the line detects other feeder terminal devices in the area and all section switches in the area;

S2: Isolate the fault according to the information detected by the feeder terminal device at the head end of the line:

S21: It is detected that the communication between the feeder terminal device and the master station is normal, and the master station sends a remote control command to the central processor, and the central processor controls the switch opening through the remote control module to complete fault isolation.

S22: It is detected that the feeder terminal devices are in the optical fiber communication mode and the section switches are all circuit breakers, then the feeder terminal device at the head end of the line isolates the fault through the interactive blocking information between the feeder terminal devices.

S23: It is detected that the terminal device of the feeder is in the wireless communication mode or the section switch is a load switch, then the section switch at the head end of the line equipped with a circuit breaker will automatically add the recloser function to control the fault current of the broken feeder, and other sections The switch isolates the point of failure by latching information.

S24: An abnormal communication between feeder terminal devices is detected, and the feeder terminal device at the head end of the line automatically adds a three-time reclosing function, which is used to complete fault isolation with voltage-time logic.

In some embodiments, the central processor collects the state of the section switch in real time through the remote signaling module, and if it detects that there is pressure on both sides of the section switch for one minute, it judges that the section switch is a tie switch.

In some implementations, after the central processing unit determines the fault point, it issues an instruction to jump to the next-level section switch and an instruction to close the tie switch. If it is judged that the fault point is near the tie switch, the feeder terminal device does not issue an instruction to close the tie switch.

Its beneficial effects are: the feeder terminal device adjusts the operation mode of the feeder terminal device in real time through the central processor according to the change of the contact point, and controls the opening and closing of the switch, that is, the optimal scheme is coordinated by the line head end switch and other segment switches. Fault isolation is completed, making the fault diagnosis and isolation of feeder automation more reliable and stable, and the implementation of distribution network automation is also easier and more convenient, avoiding the tripping of substation outlet circuit breakers and reducing the scope of power outages when faults occur.

Description of drawings

Fig. 1 is a schematic diagram of the framework of a kind of FTU that prevents over-level tripping according to an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a distribution network based on an FTU preventing over-level tripping according to an embodiment of the present invention.

The names of the corresponding parts indicated by the numbers in the figure:

11. The first substation, 12. The second substation, 101. The first section switch, 102. The second section switch, 103. The third section switch, 104. The fourth section switch, 105. The fifth section Switch, 106. Sixth segment switch, 107. Seventh segment switch, 201. First feeder terminal device, 202. Second feeder terminal device, 203. Third feeder terminal device, 204. Fourth feeder terminal device, 205. Fifth feeder terminal device, 206. Sixth feeder terminal device, 207. Seventh feeder terminal device, 21. Telemetry module, 22. Remote signaling module, 23. Remote control module, 24. Communication module, 25. Power supply module, 26. Central processing unit, 3. Master station.

Detailed ways

As shown in FIGS. 1-2 , the present invention discloses an FTU-based power distribution network, including a first substation 11 and a second substation 12 . A plurality of section switches are provided between the first substation 11 and the second substation 12 . The section switch is equipped with a feeder terminal device. The feeder terminal devices are connected sequentially. The feeder terminal device at the head end of the outgoing line of the first substation 11 is connected to the main station 3 , and the feeder terminal device at the head end of the outgoing line of the second substation 12 is connected to the main station 3 . The section switch at the head end of the outgoing line of the first substation 11 is equipped with a first circuit breaker, and the section switch at the head end of the outgoing line of the second substation 12 is equipped with a second circuit breaker.

In this embodiment, a first section switch 101, a second section switch 102, a third section switch 103, a fourth section switch 104, a fifth A segment switch 105 , a sixth segment switch 106 and a seventh segment switch 107 . The first feeder termination device 201 is arranged on the first section switch 101, the second feeder termination device 202 is arranged on the second section switch 102, the third feeder termination device 203 is arranged on the third section switch 103, the fourth The fourth feeder termination device 204 is arranged on the section switch 104, the fifth feeder termination device 205 is arranged on the fifth section switch 105, the sixth feeder termination device 206 is arranged on the sixth section switch 106, and the seventh section switch A seventh feeder termination device 207 is disposed on the switch 107 . The first feeder terminal device 201, the second feeder terminal device 202, the third feeder terminal device 203, the fourth feeder terminal device 204, the fifth feeder terminal device 205, the sixth feeder terminal device 206 and the seventh feeder terminal device 207 are connected in sequence . The first feeder terminal 201 is connected to the main station 3 of the distribution network, and the seventh feeder terminal 207 is connected to the main station 3 of the distribution network. The feeder terminal device includes a telemetry module 21 for collecting analog values of electrical quantities on the feeder, a remote signaling module 22 for collecting the state of the section switch, a remote control module 23 for controlling the opening and closing of the section switch, and a communication module 24 and a power supply module 25 for power supply. The telemetering module 21 , the remote signaling module 22 , the remote control module 23 , the communication module 24 and the power supply module 25 are respectively connected with the central processing unit 26 .

The method for diagnosing and isolating faults based on an FTU distribution network includes the following steps:

S1: The feeder terminal device closest to the outgoing line of the substation is defined as the feeder terminal device at the first end of the line. The feeder terminal device at the first end of the line detects other feeder terminal devices in the power distribution area and all section switches in the power distribution area.

The feeder terminal device at the head end of the line can receive status information messages from other feeder terminal devices through optical fiber or wireless communication, and detect other feeder terminal devices in the area and all section switches in the area according to the message content;

S2: Isolate the fault according to the information detected by the feeder terminal device at the head end of the line:

S21: It is detected that the communication between the feeder terminal device and the master station is normal, and the master station sends a remote control command to the central processor, and the central processor controls the switch opening through the remote control module to complete fault isolation.

The central processor 26 supports the centralized feeder automation mode of the master station 3. When all feeder terminal devices in the power distribution area communicate normally with the master station 3 of the distribution network, the feeder terminal devices preferably adopt the centralized mode, and the master station 3. Send a remote control instruction to the central processing unit 26, and the central processing unit 26 controls the switch opening through the remote control module 23 to complete fault isolation. The feeder terminal device judges whether the terminal communication is normal according to whether it receives the message from the master station. If any feeder terminal device in the power distribution area detects that the communication with the master station is abnormal, the device will automatically switch to the intelligent distribution mode.

S22: It is detected that the feeder terminal devices are in the optical fiber communication mode and the section switches are all circuit breakers, then the feeder terminal device at the head end of the line isolates the fault through the interactive blocking information between the feeder terminal devices.

After the feeder terminal device at each section switch detects the overcurrent information, it will send blocking information to the upper feeder terminal device. Due to the fast communication speed in optical mode, sending and receiving messages between devices is less than 5ms, so the feeder terminal device can complete fault point identification and fault isolation within 80ms. As long as the circuit breaker at the exit of the first substation is set to over-current one-stage delay time greater than 80 ms, it can be ensured that the circuit breaker at the exit of the first substation will not trip.

S23: It is detected that the feeder terminal device is in wireless communication mode or the section switch is a load switch, then the section switch at the head end of the line is equipped as a circuit breaker, and the corresponding feeder terminal device automatically adds a recloser function to control the fault current of the broken feeder , other sub-section switches isolate fault points through latching information.

The first substation outlet circuit breaker over-current delay is set to be greater than 80ms, and the feeder terminal device with recloser function is set to 0ms. After a fault occurs, the head-end section switch pulls off the fault current, and the other sub-sections The section switch isolates the fault point through blocking information, and then the head-end section switch recloses once to complete the restoration of power supply in the non-faulty area.

S24: An abnormal communication between feeder terminal devices is detected, and the feeder terminal device at the head end of the line automatically adds three reclosing functions. According to the logic of voltage-time feeder automation, it cooperates with other section switches to complete fault isolation.

After the line fault, the head-end switch trips with zero delay, and then recloses for the first time in 0.5 seconds. If it is an instantaneous fault, the switch is closed successfully. The logic of the gate is disconnected. After a period of time (2 seconds), the head-end switch recloses for the second time, and the other sub-section switches are closed in sequence according to the logic of pressure closing. After the switch closest to the fault point closes the fault, the line The head-end switch detects an overcurrent trip, and after 5 seconds, the head-end switch recloses for the third time, and the other section switches are closed in sequence according to the logic of pressure closing, and the switch closest to the fault point is closed according to the logic lock, so that Complete fault isolation.

The central processor of the feeder terminal device collects the state of the section switch in real time through the remote signaling module, and detects that there is pressure on both sides of the section switch for one minute, and then judges that the section switch is open as a tie switch. After the central processing unit of the feeder terminal device judges the fault point, it sends out the instruction of jumping to the subsection switch and the instruction of closing the tie switch. If it is judged that the fault point is near the tie switch, the feeder terminal device will not send the tie switch command. Prevent the contact switch from closing on the fault, and expand the fault range.

The feeder terminal device adjusts the operation mode of the feeder terminal device in real time through the central processor according to the change of the contact point, and controls the opening and closing of the switch, that is, the fault isolation is completed by the optimal scheme through the cooperation of the head end switch and other segment switches, so that The fault diagnosis and isolation of feeder automation are more reliable and stable, and the implementation of distribution network automation is also easier and more convenient, avoiding tripping of substation outlet circuit breakers and reducing the scope of power outages in case of faults.

An example of this embodiment is:

S1: The feeder terminal device 201 at the line head end and the feeder line terminal device 207 at the line head end detect other feeder terminal devices and all section switches between the power distribution area of the first substation 11 and the second substation 12 .

S2: Judging the detected information according to the feeder terminal device 201 at the head end of the line and the feeder device 207 at the head end of the line:

S23: The feeder terminal device 201 at the line head end and the feeder line device 207 at the line head end detect that the feeder line terminal devices in the power distribution area are in the wireless communication mode or the section switch in the power distribution area is a load switch, then the branch line at the line head end The circuit breaker equipped on the section switch enables the corresponding feeder terminal device to automatically add the recloser function to break the feeder fault current, and other sections in the power distribution area isolate the fault point through blocking information.

The above description has fully disclosed the specific implementation manners of the present invention. It should be pointed out that any changes made by those skilled in the art to the specific embodiments of the present invention will not depart from the scope of the claims of the present invention. Accordingly, the scope of the claims of the present invention is not limited only to the foregoing specific embodiments.

Claims (4)

1. The distribution network based on FTU is characterized in that, comprising a first substation and a second substation, a plurality of subsection switches are arranged between the first substation and the second substation, and the subsection switches are equipped with There is a feeder terminal device, and the feeder terminal devices are connected in sequence, the feeder terminal device at the head end of the outgoing line of the first substation is connected to the main station, and the feeder terminal device at the head end of the outgoing line of the second substation is connected to the main station, so The sectional switch at the head end of the outgoing line of the first substation is equipped with a first circuit breaker, and the sectional switch at the head end of the outgoing line of the second substation is equipped with a second circuit breaker, The method for diagnosing and isolating faults in an FTU-based distribution network includes the following steps: S1: The feeder terminal device at the head end of the line detects other feeder terminal devices in the area and all section switches in the area; S2: Isolate the fault according to the information detected by the feeder terminal device at the head end of the line: S21: It is detected that the communication between the feeder terminal device and the master station is normal, the master station sends a remote control command to the central processor, and the central processor controls the switch opening through the remote control module to complete fault isolation, S22: It is detected that the feeder terminal devices are in the optical fiber communication mode and the section switches are all circuit breakers, then the feeder terminal device at the head end of the line isolates the fault through the interactive blocking information between the feeder terminal devices, S23: It is detected that the terminal device of the feeder is in the wireless communication mode or the section switch is a load switch, then the section switch at the head end of the line equipped with a circuit breaker will automatically add the recloser function to control the fault current of the broken feeder, and other sections The switch isolates the fault point through blocking information, S24: An abnormal communication between feeder terminal devices is detected, and the feeder terminal device at the head end of the line automatically adds three reclosing functions. According to the logic of voltage-time feeder automation, it cooperates with other section switches to complete fault isolation. 2. The distribution network based on FTU according to claim 1, characterized in that, the feeder terminal device includes a telemetry module for collecting the analog value of the electrical quantity on the feeder, a telemetry module for collecting the state of the section switch Communication module, remote control module for controlling opening and closing of section switch, communication module for communication between feeder terminal devices and communication between feeder terminal device and main station, and power supply module for feeder terminal device, The telemetering module, remote signaling module, remote control module, communication module and power supply module are respectively connected with the central processing unit. 3. the distribution network based on FTU according to claim 1, is characterized in that, described central processing unit collects the state of section switch in real time through remote signaling module, detects that there is pressure on both sides of section switch continuously for one minute, Then it is judged that the subsection switch opens the tie switch. 4. The distribution network based on FTU according to claim 1, characterized in that, after the central processing unit has judged the point of failure, it sends an instruction to jump to the next stage segment switch and a command to close the contact switch, if it is judged that the point of failure is in the connection In the vicinity of the switch, the feeder terminal device will not issue a contact switch command.