A ring main unit protection system and protection method with mutual backup function

Abstract

The present invention provides a ring main unit protection system and a protection method with a mutual backup function, which mainly include an even number of interval unit protection devices arranged in the ring main unit, and the interval units and the protection devices are grouped in pairs, and a main program and a backup program are stored in the interval unit protection device of the ring main unit. The main program is used to monitor one line governed by each interval unit and provide protection to the interval unit when the grouping works normally, and the backup program is used to monitor two lines in the grouping at the same time and provide protection to the two interval units when an abnormality or failure occurs in one interval unit in the grouping.

Description

Technical Field

[0001] The invention relates to distribution network line equipment and a protection method thereof, and in particular to a ring network cabinet with mutual backup function and a protection method. Background Art

[0002] Ring main units are widely used at important nodes of cable networks. As important segmentation, communication, demarcation and branch nodes of the main line of the distribution network, they play a role in monitoring the operation of the distribution network lines and quickly judging, locating, isolating and restoring power supply to faulty lines. The ring main unit is composed of a ring input and output unit, a feeder unit, a busbar PT (voltage transformer) unit and protection devices installed in each bay unit. The protection device of each bay unit is responsible for the measurement, control, relay protection, communication and other functions of each bay unit. At present, the protection devices of each bay unit are independent of each other, and there is no electrical interaction and information interaction between them. When the protection device of a bay of the ring main unit fails, the measurement, protection, control and other functions of the bay will be completely paralyzed. The current processing method is:

[0003] 1. Continue to operate, but the line has no measurement, no protection, and cannot be remotely controlled. When a line fault occurs, it is impossible to monitor and isolate the fault, which can easily expand the fault and seriously affect the safety of power supply.

[0004] 2. Power outages for several hours to replace or repair protective devices will greatly affect the reliability of power supply.

[0005] Therefore, the current protection devices have no backup capacity, and their own failure or abnormality will result in the lack of monitoring and protection functions for the lines under their jurisdiction, greatly affecting the safety and reliability of power supply.

[0006] The present invention proposes a ring main unit protection system with a mutual backup function and a protection method thereof, which utilizes electrical interaction and information interaction between two protection devices in a group, and the protection devices serve as backup for each other. When a protection device fails, another protection device in the group activates the backup protection function to take over all functions of the failed protection device. When a protection device fails on the ring main unit, the entire ring main unit can continue to operate normally without changing the line structure, replacing or repairing the protection device, or shutting down the power supply, which greatly improves the safety and reliability of power supply. Summary of the invention

[0007] The present invention proposes a ring main unit protection system with mutual backup function, and the specific scheme is as follows:

[0008] A ring main unit protection system with mutual backup function, the ring main unit protection system comprises a plurality of interval unit protection devices, the interval unit protection devices correspond to the interval units in the ring main unit one by one, and is characterized in that:

[0009] Each of the bay unit protection devices stores a main program and a backup program, wherein the main program is used to monitor and report its own electrical data and protect its own line; the backup program is used to simultaneously monitor and report the electrical data of two bay units in the group and protect the two lines;

[0010] When the ring main unit protection system is working, every two interval unit protection devices form a group. When the group is working normally, each interval unit protection device only starts the main program. When an interval unit protection device in the group fails, the other interval unit protection device that is working normally automatically starts the backup program.

[0011] Furthermore, in each of the above-mentioned groups, the two interval unit protection devices independently use a three-phase current transformer to monitor the current data of the input interval unit, and send the current data collected by each to the two interval unit protection devices at the same time; the two interval unit protection devices share a three-phase voltage transformer to monitor the bus voltage data of the input interval unit, and send the collected voltage data to the two interval unit protection devices at the same time.

[0012] Furthermore, in each of the above-mentioned groups, each bay unit protection device respectively and simultaneously collects the switch opening status signal and the switch closing status signal of the two ring main units in the group.

[0013] Furthermore, the interval unit protection device realizes the collection of the switch opening state and the switch closing state through optical coupling isolation.

[0014] Furthermore, in each of the above-mentioned groups, each bay unit protection device is respectively connected to the output terminals of the two bay unit switches at the same time, and can control the opening and closing signals of the two bay units at the same time.

[0015] Furthermore, the bay unit protection device is provided with a remote communication network port, and the remote communication network port is used to report the electrical data of the bay unit to the remote master station system and receive various instructions sent by the remote master station system.

[0016] Furthermore, the bay unit protection device is provided with a self-checking network port, and the self-checking network port is used to transmit a fault signal between two bay unit protection devices in the grouping.

[0017] Furthermore, the signals collected by the three-phase current transformer and the three-phase voltage transformer are adjusted by the overvoltage protection module, the signal conditioning module and the high-speed A / D conversion module, and then sent to the CPU on the interval unit protection device. The CPU is a logic judgment unit for determining whether the working status of the interval unit protection device is normal.

[0018] Furthermore, the judgment condition of the logic judgment unit can be rewritten according to the circuit requirements.

[0019] The present invention also proposes a ring main unit protection method with mutual backup function, and the specific scheme is as follows:

[0020] A ring main unit protection method with mutual backup function, characterized in that the ring main unit protection method comprises the following steps:

[0021] S1: The main program and backup program are built into the interval unit protection device of the ring main unit;

[0022] S2: Group the bay unit protection devices in the ring main unit into groups of two, and establish a fault signal transmission channel between the two bay unit protection devices in the group;

[0023] S3: When the ring main unit operates normally, each interval unit protection device only runs the main program, monitors the electrical data of its own line and provides protection for its own line; when a fault occurs in the interval unit in the ring main unit, the protection device corresponding to the interval unit sends a fault signal to another interval unit protection device in the group through the fault signal transmission channel, shuts down the main program of the other interval unit protection device and activates the backup program, while monitoring the electrical data of the two lines in the group and providing protection for the two lines.

[0024] S4: When the ring main unit is restored to normal through on-site maintenance or overhaul, the restored normal interval unit protection device sends a fault recovery signal to another interval unit protection device in the grouping through the fault signal transmission channel, shuts down the standby program of the other interval unit protection device and enables the main program, thereby restoring the normal working condition of the ring main unit.

[0025] The use of the above-mentioned ring main unit protection system and ring main unit protection method can overcome the disadvantages of no information interaction or weak information interaction capability in the ring main unit used in the traditional distribution network line, and the need for power outage for maintenance after a fault occurs, thereby improving the safety and reliability of power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A structural diagram of an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of a spacing unit protection device in one embodiment of the present invention;

[0028] Figure 3 The figure is a schematic diagram of a grouping in one embodiment of the present invention.

[0029] Among them, 1 is the ring network cabinet, 2 is the interval unit protection device, 3 is the three-phase voltage transformer, 4 is the three-phase current transformer, 5 is the three-phase voltage acquisition transmission cable, 6 is the three-phase current acquisition transmission cable, 7 is the status and control acquisition transmission cable, and 8 is the self-test signal interaction network port. DETAILED DESCRIPTION

[0030] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0031] like Figure 1 As shown, in one embodiment of the present invention, the ring main unit is equipped with a ring inlet and outlet unit, a feeder unit and a PT unit, a vacuum interrupter is equipped with a fully insulated and fully sealed stainless steel shell, a built-in vacuum circuit breaker, and an interval unit protection device with a mutual backup function is installed in the secondary room. The automatic control structure is composed of a main control board, a liquid crystal display, operation buttons, indicator lights, a self-test network port, a remote communication network port and wiring terminals.

[0032] In this embodiment, there are 6 bay units and their corresponding protection devices, which are grouped in pairs to form 3 mutually standby groups. In each group, the electrical connection structure is the same. The structure and function of one group are described in detail below.

[0033] The three-phase voltage transformer is placed inside the ring network cabinet to collect the three-phase voltage signals of A, B, and C in the power supply line in real time, and is connected to the interval unit protection device through a three-phase voltage collection transmission cable. The collection bandwidth of the three-phase voltage transformer is 0-4khz, and the accuracy is 1%. The three-phase voltage collection transmission cable is a coaxial cable, which transmits the voltage signal collected by the three-phase voltage transformer in real time.

[0034] The three-phase current transformer is placed inside the ring network cabinet, and collects the A, B, and C three-phase current signals in each interval unit loop in real time, and is connected to the two interval unit protection devices in each group through the three-phase current collection transmission cable. The sampling bandwidth is 0-4khz, and the accuracy is 0.5%. A ring network cabinet has multiple three-phase current transformers built in. The three-phase current collection transmission cable is a coaxial cable, which transmits the voltage signal collected by the three-phase current transformer in real time.

[0035] The status and control transmission cable is a coaxial cable, which transmits the status signal between the two bay unit protection devices in each group in real time. At the same time, the bay unit protection device also transmits the opening and closing control signal through the status and control transmission cable.

[0036] In each marshaling, two bay unit protection devices with mutual backup functions are each provided with a self-test network port, which is an RJ45 network port for exchanging self-test signals. When a protection device fails or is abnormal, another bay unit protection device in the marshaling that is working normally receives the fault signal sent by the faulty bay unit protection device through the self-test network port and starts the backup program. At this time, all signal collection, protection and communication functions of the lines governed by the faulty or abnormal bay unit protection device are undertaken by the bay unit protection device that is working normally in the marshaling. That is, the bay unit protection device that is working normally undertakes the collection, protection and communication functions of the electrical signals of the two lines in the marshaling.

[0037] A remote communication network port is provided on each bay unit protection device. The remote communication network port is used to upload the line signal collected by the bay unit protection device to the remote master station system and receive various instructions sent by the remote master station system. The remote communication network port is an RJ45 network port.

[0038] Two sets of programs are stored in each isolation unit protection device with mutual backup function: the first set is the main program, that is, the program running under normal circumstances of the protection device, which is only responsible for the data collection, protection and communication functions of this interval unit; the second set is the backup program, that is, when an adjacent protection device fails, the main program switches to the backup program, and the backup program is responsible for the data collection, protection and communication functions of this interval unit and the adjacent interval units.

[0039] When the power grid maintenance personnel restore a faulty or abnormal protection device to normal through on-site maintenance or overhaul, the adjacent protection devices exchange information through the self-test network port, automatically start the main program, shut down the backup program, and each return to normal working status.

[0040] Figure 2 The figure shows the principle and connection relationship of a spacing unit protection device. Figure 2 As shown, in each bay unit protection device, a STM32f407VG DSC chip is used as a logic judgment CPU, which is responsible for judging the working state of the bay unit protection device according to the voltage and current parameters of the controlled line. If the working state is normal, the main program in the bay unit protection device is enabled to work, and the working state and the electrical parameters of the line are reported to the remote master station through the remote communication network port. If the working state is a fault, the standby program in the bay unit protection device is enabled to work, and the working state and the electrical parameters of the line are reported to the remote master station through the remote communication network port.

[0041] In this embodiment, the parameters input to the CPU include the three-phase current transformer signal of the line governed by the interval unit, the three-phase current transformer signal of the line governed by the adjacent unit in the grouping, and the three-phase voltage transformer signal of the busbar. Before the above three groups of signals are input to the CPU, they must be processed by the overvoltage protection module, the signal conditioning module, and the high-speed A / D conversion module in sequence. The overvoltage protection module uses a 12V / 5A voltage regulator, and the voltage stabilization part is composed of a 7805 three-terminal voltage regulator and a current expansion transistor. The potential of its adjustment end is raised by a voltage regulator diode and a light-emitting diode in series. The overvoltage protection uses a thyristor short-circuit power supply to force the fuse to blow quickly to protect the safety of the subsequent circuit. The function of the signal conditioning module is to convert the collected ±3~5V voltage signal into a ±2~3mA current signal. The high-speed A / D sampling module is an AD9252 chip.

[0042] In this embodiment, the CPU of each interval unit protection device is also isolated by the TLP112 optocoupler, so as to safely collect the opening status signal and closing status signal of the interval unit protection device and the adjacent interval unit protection device, and determine the transmission destination of the aforementioned contacts and status signals according to the working status of the interval unit.

[0043] Figure 3 The principle and connection relationship of two bay unit protection devices in one marshaling are shown. In the other two marshalings of this embodiment, the principle and connection relationship of the two bay unit protection devices are the same as those of this marshaling.

[0044] On the 1-bay unit protection device, there are: two groups of three-phase current transformer signal terminals Ia1, Ib1, Ic1, In1 and Ia2', Ib2', Ic2', In2'; one group of three-phase voltage transformer signal terminals Ua, Ub, Uc, Un; 1 bay unit switch opening state signal terminal Rf1; 1 bay unit switch closing state signal terminal Rh1; 2 bay unit switch opening state signal terminals Rf2; 2 bay unit switch closing state signal terminals Rh2; 1 bay unit opening output terminal Of1; 1 bay unit closing output terminal Oh1; 2 bay unit opening output terminals Of2; 2 bay unit closing output terminals Oh2.

[0045] On the 2-bay unit protection device, there are: two groups of three-phase current transformer signal terminals Ia2, Ib2, Ic2, In2 and Ia1', Ib1', Ic1', In1'; one group of three-phase voltage transformer signal terminals Ua, Ub, Uc, Un; 2 bay unit switch opening state signal terminals Rf2; 2 bay unit switch closing state signal terminals Rh2; 1 bay unit switch opening state signal terminal Rf1; 1 bay unit switch closing state signal terminal Rh1; 2 bay unit opening output terminals Of2'; 2 bay unit closing output terminals Oh2'; 1 bay unit opening output terminal Of1'; 1 bay unit closing output terminal Oh1'.

[0046] In this embodiment, Ia1 is connected in series with Ia1', Ib1 is connected in series with Ib1', Ic1 is connected in series with Ic1', and In1 is connected in series with In1'; Ia2 is connected in series with Ia2', Ib2 is connected in series with Ib2', Ic2 is connected in series with Ic2', and In2 is connected in series with In2'. In the above connection mode, the protection device of the 1st interval unit simultaneously collects the three-phase current signal of the 1st interval unit and the three-phase current signal of the 2nd interval unit through the terminal series connection, and the protection device of the 2nd interval unit simultaneously collects the three-phase current signal of the 2nd interval unit and the three-phase current signal of the 1st interval unit through the terminal series connection. The protection device of the 1st interval unit and the protection device of the 2nd interval unit each collect the three-phase voltage signal of the same voltage transformer, that is, Ua, Ub, Uc.

[0047] Rf1 and Rf2 are connected in parallel, and Rh1 and Rh2 are connected in parallel. In the above connection mode, the 1 bay unit protection device simultaneously collects the switch opening and closing state signals of the 1 bay unit and the 2 bay units through the terminals in parallel, and the 2 bay unit protection device simultaneously collects the switch opening and closing state signals of the 2 bay units and the 1 bay unit through the terminals in parallel.

[0048] Of1, Oh1, Of2 and Oh2 are connected to the 1 bay unit protection device, and Of1', Oh1', Of2' and Oh2' are connected to the 2 bay unit protection device. In the above connection mode, the 1 bay unit protection device can simultaneously control the opening and closing of the switches of the 1 bay unit and the 2 bay unit, and the 2 bay unit protection device can simultaneously control the opening and closing of the switches of the 2 bay unit and the 1 bay unit.

[0049] The self-check network port of the protection device of the 1st bay unit and the self-check network port of the protection device of the 2nd bay unit are connected through a network cable to exchange information with each other. When the protection device of the 1st bay unit self-checks that it has a fault or an abnormality, the fault or abnormality information is sent to the protection device of the 2nd bay unit, and the protection device of the 2nd bay unit starts the backup program, and all the original functions of the protection device of the 1st bay unit are realized by the protection device of the 2nd bay unit. Conversely, when the protection device of the 2nd bay unit self-checks that it has a fault or an abnormality, the fault or abnormality information is sent to the protection device of the 1st bay unit, and the protection device of the 1st bay unit starts the backup program, and all the original functions of the protection device of the 2nd bay unit are realized by the protection device of the 1st bay unit.

[0050] The remote communication network port sends information to the remote master station system for the protection devices in each interval, and receives various instructions from the remote master station system.

[0051] When the line conditions of the ring main unit in this embodiment change, the power grid maintenance personnel can send update instructions through the remote master station system, or update the main program and backup program through other means to change the judgment conditions for the normal working conditions of the interval unit.

[0052] The above is a detailed introduction to the analog signal short-distance wireless transmission device provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technicians in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope, and the content of this specification should not be understood as a limitation on the technical solution of the present invention.

Claims

1. A ring main unit protection system with mutual backup function, the ring main unit protection system comprising a plurality of interval unit protection devices, the interval unit protection devices corresponding to the interval units in the ring main unit one by one, characterized in that: Each of the bay unit protection devices stores a main program and a backup program, wherein the main program is used to monitor and report its own electrical data and protect its own line; the backup program is used to simultaneously monitor and report the electrical data of two bay units in the group and protect the two lines; When the ring main unit protection system is working, every two interval unit protection devices form a group. When the group is working normally, each interval unit protection device only starts the main program. When one interval unit protection device in the group fails, another interval unit protection device that is working normally automatically starts the standby program. In each of the marshaling groups, the two bay unit protection devices independently use a three-phase current transformer to monitor the current data of the input bay unit, and send the respectively collected current data to the two bay unit protection devices simultaneously; The two bay unit protection devices share a three-phase voltage transformer to monitor the bus voltage data of the input bay unit, and send the collected voltage data to the two bay unit protection devices at the same time; In each of the above-mentioned groups, each bay unit protection device respectively and simultaneously collects the switch opening state signal and the switch closing state signal of the two ring main units in the group.

2. The ring main unit protection system according to claim 1, characterized in that: The interval unit protection device realizes the collection of the switch opening state and the switch closing state through optical coupling isolation.

3. The ring main unit protection system according to claim 2, characterized in that: In each of the above-mentioned groups, each bay unit protection device is respectively connected to the output terminals of the two bay unit switches at the same time, and can control the opening and closing signals of the two bay units at the same time.

4. The ring main unit protection system according to claim 1, characterized in that: The bay unit protection device is provided with a remote communication network port, which is used to report the electrical data of the bay unit to the remote master station system and receive various instructions sent by the remote master station system.

5. The ring main unit protection system according to any one of claims 1 to 3, characterized in that: The interval unit protection device is provided with a self-checking network port, and the self-checking network port is used to transmit a fault signal between two interval unit protection devices in the grouping.

6. The ring main unit protection system according to claim 5, characterized in that: The signals collected by the three-phase current transformer and the three-phase voltage transformer are sent to the CPU on the interval unit protection device after being adjusted by the overvoltage protection module, the signal conditioning module and the high-speed A / D conversion module. The CPU is a logic judgment unit for judging whether the working state of the interval unit protection device is normal.

7. The ring main unit protection system according to claim 6, characterized in that: The judgment condition of the logic judgment unit can be rewritten according to the circuit requirements.

8. A ring main unit protection method applied to the ring main unit protection system according to claim 1, characterized in that: The ring main unit protection method comprises the following steps: S1: a main program and a standby program are built into a bay unit protection device of the ring main unit; S2: Group the bay unit protection devices in the ring main unit into groups of two, and establish a fault signal transmission channel between the two bay unit protection devices in the group; S3: When the ring main unit works normally, each bay unit protection device only runs the main program, monitors the electrical data of its own line and provides protection for its own line; when a bay unit in the ring main unit fails, the protection device corresponding to the bay unit sends a fault signal to another bay unit protection device in the group through the fault signal transmission channel, shuts down the main program of the other bay unit protection device and activates the standby program, and monitors the electrical data of the two lines in the group and provides protection for the two lines at the same time; S4: When the ring main unit is restored to normal through on-site maintenance or overhaul, the restored normal interval unit protection device sends a fault recovery signal to another interval unit protection device in the grouping through the fault signal transmission channel, shuts down the standby program of the other interval unit protection device and enables the main program, thereby restoring the normal working condition of the ring main unit.

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