A fault self-healing distribution terminal adapted to the new distribution system

Abstract

The present invention discloses a fault self-healing distribution terminal adapted to a new type of power distribution system, which relates to the field of power supply backup power supply devices and is used to improve the safety and stability of the distribution network. The fault self-healing distribution terminal receives the alarm signal sent by the SCADA system, and determines whether a low-frequency and low-voltage load reduction action signal is received. If so, the backup automatic switch is locked. Otherwise, it is determined whether the fault occurrence section is the incoming line section or the bus section according to the alarm signal. When the fault occurrence section is the incoming line section, or when the fault occurrence section is the bus section and the fault load has been isolated, it is determined whether the distributed power source is connected. If not, the backup automatic switch is directly enabled. Otherwise, according to the relationship between the connected distributed power source and the load, the load or the distributed power source is first processed, and then the backup automatic switch is enabled. The present invention enables the backup automatic switch to adapt to different distribution network fault conditions and distributed power source access conditions.

Description

Technical Field

[0001] The present invention relates to the field of power supply backup power supply devices, and in particular to a fault self-healing distribution terminal which is deployed in a new distribution system connected to a distributed power source (DG) and is adapted to the new distribution system. Background Art

[0002] At present, there is a certain contradiction between the three lines of defense of the power system and the self-healing methods of distribution network faults such as automatic backup and automatic feeder automation. For example, in order to ensure the safe and stable operation of the power grid, the low-frequency and low-voltage load reduction device needs to cut off the line load in emergency situations such as extreme faults or insufficient power output. However, the load that has been cut off will be transferred due to the self-healing functions of the distribution network faults such as automatic backup and automatic feeder automation, resulting in the re-connection of the load that has been cut off to the distribution network, and the safety and stability issues of the power system still exist.

[0003] In addition, due to the widespread access of various distributed power sources, in the event of a distribution network failure, the instability of the distribution network current will affect the commissioning of the backup automatic start-up device, and may even lead to serious situations such as the backup automatic start-up device refusing to operate or asynchronous closing. Summary of the invention

[0004] The object of the present invention is to provide a fault self-healing distribution terminal adapted to a new type of distribution system in order to solve all or part of the above-mentioned problems. The fault self-healing distribution terminal is arranged before the standby automatic switching device so that the standby automatic switching device can adapt to different distribution network fault conditions and distributed power supply access conditions.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A fault self-healing distribution terminal adapted to a new type of power distribution system, wherein the fault self-healing distribution terminal is configured as follows:

[0007] Receive the alarm signal sent by the SCADA (Supervisory Control And Data Acquisition) system, generate a control signal according to the access status of the distributed power source, and transmit the control signal to the switchgear in the power system; the alarm signal is generated by the SCADA system according to the outgoing circuit breaker trip signal generated by the power system;

[0008] The method for generating a control signal by a fault self-healing power distribution terminal includes:

[0009] Determine whether the low-frequency and low-voltage load shedding action signal is received. If so, lock the standby automatic transfer, otherwise proceed to the next step;

[0010] According to the alarm signal, it is determined whether the fault section is the incoming line section or the bus section. When the fault section is the incoming line section, or when the fault section is the bus section and the faulty load has been isolated, corresponding actions are performed on the backup automatic switch according to the access status of the distributed power source.

[0011] Furthermore, when the fault section is the bus section and the fault load has been isolated, the backup automatic switch is executed according to the access status of the distributed power source, including:

[0012] When the fault occurs in the busbar section, determine whether the faulty load has been isolated. If so, perform corresponding actions on the standby automatic switch according to the distributed power supply access situation. If the faulty load has not been isolated, wait until the faulty load is isolated, and then perform corresponding actions on the standby automatic switch according to the distributed power supply access situation, and lock the standby automatic switch during the waiting period.

[0013] Furthermore, the performing corresponding actions on the backup automatic switch according to the access status of the distributed power source includes:

[0014] Determine whether the distributed power source is connected. If not, directly enable the backup automatic transfer. Otherwise, based on the relationship between the connected distributed power source and the load, first process the load or distributed power source, and then enable the backup automatic transfer.

[0015] Furthermore, the process of first processing the load or distributed power source and then enabling the backup automatic switching according to the relationship between the connected distributed power source and the load includes:

[0016] If the output of the distributed generation is less than the load, the synchronous device will cut off part of the load and then activate the standby automatic switch;

[0017] If the output of the distributed power source is greater than the load, the distributed unit will be completely cut off and the backup automatic switch will be enabled.

[0018] Further, when determining whether a low-frequency and low-voltage load shedding action signal is received, if no low-frequency and low-voltage load shedding action signal is received within a set predetermined time interval, the next step is executed.

[0019] Furthermore, the fault self-healing distribution terminal is also configured as:

[0020] Receive remote control instructions from the distribution automation system and pass them to the standby automatic switch so that the standby automatic switch responds to the remote control instructions and performs corresponding actions.

[0021] Furthermore, the remote control command is generated and issued by the distribution automation system when the distribution automation system monitors that the standby automatic switching fails to operate or fails to execute the action.

[0022] Furthermore, the fault self-healing distribution terminal does not receive remote control instructions from the distribution automation system during the generation of the control signal.

[0023] Furthermore, the fault self-healing distribution terminal includes a small current grounding fault analysis module, a circuit breaker failure protection module, and a locking standby automatic re-throwing function module, and the control signal is generated by the locking standby automatic re-throwing function module.

[0024] The present invention also provides a power distribution system, which includes a distributed power supply, a distribution automation system and a fault self-healing distribution terminal adapted to a new distribution system, wherein the distribution automation system includes a SCADA system; the distribution automation system and the fault self-healing distribution terminal are respectively connected to the power system, the distribution automation system is connected to the fault self-healing distribution terminal, and the fault self-healing distribution terminal is connected to the distributed power supply.

[0025] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0026] The present invention sets a fault self-healing distribution terminal in front of the standby automatic start-up device, and formulates a clear standby automatic start-up state control strategy according to the specific fault type and the access situation of distributed power sources, so that the standby automatic start-up device can adapt to different distribution network fault conditions and distributed power source access conditions, thereby improving the safety and stability of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0028] Figure 1 It is a control architecture diagram of a power distribution system in which the fault self-healing power distribution terminal of the present invention is deployed.

[0029] Figure 2 It is an embodiment of the control signal generation process.

[0030] Figure 3 It is an embodiment of the fault self-healing power distribution terminal architecture design of the present invention.

[0031] Figure 4 It is an embodiment of the circuit diagram of #1 switchgear station. DETAILED DESCRIPTION

[0032] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0033] Any feature disclosed in this specification (including any additional claims and abstract), unless otherwise stated, may be replaced by other alternative features that are equivalent or have similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0034] Example 1

[0035] A fault self-healing distribution terminal (referred to as a fault self-healing distribution terminal) adapted to a new type of distribution system is deployed in a distribution system connected to a distributed power source to improve the safety and stability of the power system.

[0036] The operating part of the distribution system is the power system, which includes distributed power sources, distribution automation system, and fault self-healing distribution terminals. The distribution automation system includes a SCADA system. The distribution automation system and the fault self-healing distribution terminal are connected to the power system respectively. The distribution automation system is connected to the fault self-healing distribution terminal, and the fault self-healing distribution terminal is connected to the distributed power source.

[0037] like Figure 1 As shown, the outgoing circuit breaker trip signal generated by the power system is transmitted to the SCADA system. The SCADA system generates an alarm signal based on the outgoing circuit breaker trip signal generated by the power system and sends it to the fault self-healing distribution terminal. The fault self-healing distribution terminal is configured as follows:

[0038] Receive the alarm signal sent by the SCADA system, generate a control signal according to the access status of the distributed power source, and transmit the control signal to the switchgear in the power system.

[0039] According to the control signal generated by the fault self-healing distribution terminal, the state of the standby automatic switch under the corresponding fault can be clearly controlled to prevent the safety hazards from being not completely eliminated due to the self-healing function of the distribution network and other reasons.

[0040] See attached Figure 2 , the method for generating a control signal by a fault self-healing distribution terminal includes:

[0041] S1. Determine whether a low-frequency and low-voltage load reduction action signal is received. If so, lock the standby automatic transfer. Otherwise, execute the next step S2.

[0042] In step S1, the judgment of whether the low-frequency and low-voltage load shedding action signal is received may be a judgment of the receiving state or a judgment of the receiving result. In some embodiments, when judging whether the low-frequency and low-voltage load shedding action signal is received, if the low-frequency and low-voltage load shedding action signal is not received within the set predetermined time interval T, the next step is executed, and the predetermined time interval T here is usually in seconds.

[0043] In addition, the fault self-healing distribution terminal is equipped with a data transmission unit (DTU). If a low-frequency and low-voltage load reduction action signal is received, it will be stored in the data transmission unit. The judgment of whether a low-frequency and low-voltage load reduction action signal is received is to judge whether there is a low-frequency and low-voltage load reduction action signal in the data transmission unit.

[0044] For example, Figure 4 In the illustrated embodiment, after the low-frequency and low-voltage load shedding device is actuated, the low-frequency and low-voltage load shedding action signal is uploaded to the dispatching automation system, the dispatching automation system sends the low-frequency and low-voltage load shedding action signal to the distribution automation system, and finally the distribution automation system sends the low-frequency and low-voltage load shedding action signal to the data transmission unit in the new distribution terminal. If the data transmission unit receives the action signal of the low-frequency and low-voltage load shedding device, a locking signal is sent to the standby automatic switch to lock the standby automatic switch. If the data transmission unit does not receive the action signal of the low-frequency and low-voltage load shedding device, it should wait for the distribution automation system to send a fault signal and lock the standby automatic switch to avoid the "#1 switch station" triggering the standby automatic switch due to the loss of pressure on the I bus, and directing the load to other lines.

[0045] S2. Determine whether the fault-occurring section is the incoming section or the bus section based on the alarm signal. When the fault-occurring section is the incoming section, or when the fault-occurring section is the bus section and the faulty load has been isolated, perform corresponding actions on the backup automatic switch based on the access status of the distributed power source.

[0046] This step is divided into two fault response situations: one is the backup automatic transfer control strategy for incoming line section faults, and the other is the backup automatic transfer control strategy for busbar section faults.

[0047] The alarm signal is the incoming line protection signal, through which it can be determined whether the fault occurs in the incoming line section or the bus section. For these two types of faults, the fault self-healing distribution terminal obtains the control signal by querying the control strategy corresponding to the fault type.

[0048] S21. If the fault occurs in the incoming line section, corresponding actions will be taken on the backup automatic switch according to the access status of the distributed power source.

[0049] S22. If the fault occurs in the busbar section, determine whether the faulty load has been isolated; if the faulty load has been isolated, perform corresponding actions on the standby automatic switch according to the distributed power supply access situation; if the faulty load has not been isolated, wait until the faulty load is isolated, and then perform corresponding actions on the standby automatic switch according to the distributed power supply access situation, and lock the standby automatic switch during the waiting period.

[0050] In the above steps, the corresponding actions are performed on the backup automatic switch according to the access status of the distributed power source. In some embodiments, Figure 2 As shown, including:

[0051] Determine whether the distributed power source is connected. If not, directly enable the backup automatic transfer. Otherwise, based on the relationship between the connected distributed power source and the load, first process the load or distributed power source, and then enable the backup automatic transfer.

[0052] The relationship between distributed generation and load refers to whether the output of distributed generation meets the load. Specifically, there are the following response strategies:

[0053] If the output of the distributed generation is less than the load, the synchronous device will cut off part of the load and then activate the standby automatic switch;

[0054] If the output of the distributed power source is greater than the load, the distributed unit will be completely cut off and the backup automatic switch will be enabled.

[0055] like Figure 4 As shown, in one embodiment, it is assumed that a fault occurs between the substation outlet switch "Dacai-933" and "#1 switch 601", that is, an incoming line fault occurs, and the substation outlet switch "Dacai-933" trips. The distribution automation system gives the fault section as the incoming line section, activates the 601 incoming line protection alarm, and opens the "#1 switch 601". At the same time, if there is a distributed power source, the current and voltage values ​​related to the flow should be calculated to determine whether the output of the distributed power source is less than the load.

[0056] If the output of the distributed generation is less than the load, cooperate with the synchronization device to cut off some unimportant loads, and finally directly activate the backup automatic switch and close the "#1 switch station 620".

[0057] If the output of the distributed power source is greater than the load, the backup automatic start-up plan given by the experts or workers should be waited for, and the backup automatic start-up device should be locked during the waiting period. After the distributed power source is completely cut off according to the backup automatic start-up plan received, the backup automatic start-up device can be started.

[0058] If the backup automatic switch refuses to operate or fails to operate in the entire logical process, such as the failure of "#1 switch 601" to open or the failure of "#1 switch 620" to close, the distribution automation system will issue a remote control command to directly control the backup automatic switch to perform the corresponding action. That is, the distribution system is also designed with a distribution automation system fault self-healing strategy. When the backup automatic switch fails to perform the action normally, the distribution automation system directly performs remote control.

[0059] The distribution automation system monitors the backup automatic switch action in real time. When the backup automatic switch refuses to operate or fails to execute the action, it sends a remote control signal to control the backup automatic switch action. For the fault self-healing distribution terminal, it receives the remote control command of the distribution automation system and transmits it to the backup automatic switch, so that the backup automatic switch responds to the remote control command and executes the corresponding action.

[0060] In another embodiment, the busbar of section I of "#1 switch station" is faulty. As in the previous embodiment, the outgoing switch "Dacai-933" of the substation will also trip. At this time, the distribution automation system indicates that the fault area is a busbar fault, and performs fault isolation detection at the same time.

[0061] If the faulty load has not been isolated, the standby automatic transfer function cannot be directly activated. You should wait until the faulty load is isolated before activating the standby automatic transfer function. That is, the standby automatic transfer function should be locked while waiting for the fault isolation signal.

[0062] If the fault has been isolated and there is a distributed generation, the current and voltage values ​​related to the flow should be calculated to determine whether the output of the distributed generation is less than the load.

[0063] If the output of the distributed generation is less than the load, cooperate with the synchronization device to cut off some unimportant loads, and finally directly activate the backup automatic switch, that is, open the "#1 switch station 601" and close the "#1 switch station 620".

[0064] If the output of the distributed power source is greater than the load, the backup automatic start-up plan given by the experts or workers should be waited for, and the backup automatic start-up device should be locked during the waiting period. After the distributed power source is completely cut off according to the backup automatic start-up plan received, the backup automatic start-up device can be started.

[0065] Similarly, if the backup automatic switch refuses to operate or fails to operate during the entire logical process, such as the failure to open the "#1 switch station 601" or the failure to close the "#1 switch station 620", the distribution automation system will issue a remote control command to directly control the backup automatic switch to perform corresponding actions.

[0066] It should be noted that when a fault occurs in the distribution network, the backup automatic switch will be activated first to deal with the fault. However, from the time the fault self-healing distribution terminal is aware of the fault to the time it generates the corresponding control signal (query control strategy), there is no need for the distribution automation system to forcibly intervene in the backup automatic switch. Therefore, it is considered to lock the fault self-healing function of the distribution automation system during the period when the fault self-healing distribution terminal generates the control signal, and the fault self-healing distribution terminal does not receive the remote control command of the distribution automation system during this period.

[0067] Example 2

[0068] In addition to optimizing the automatic backup lockout logic, as another improvement of the present invention, the fault self-healing distribution terminal integrates multiple equipment functions. Combined with the fault self-healing distribution terminal, the distribution system can adopt three implementation schemes of local differential protection, automatic backup control strategy and distribution automation system fault self-healing in sequence, and adapt to different fault conditions and distributed power supply access conditions.

[0069] like Figure 3 As shown, the fault self-healing distribution terminal includes a small current grounding fault analysis module, a circuit breaker failure protection module, and a locking standby automatic re-throwing function module. The control signal is generated by the locking standby automatic re-throwing function module, that is, the standby automatic re-throwing control logic introduced in Example 1 is implemented by the locking standby automatic re-throwing function module.

[0070] The small current grounding fault analysis module has the functions of PT detuning, wheel cutting, reclosing, post-acceleration tripping, and fault number statistics. The outgoing line circuit breaker failure protection module can quickly isolate adjacent intervals when the outgoing line circuit breaker refuses to operate to avoid tripping on the substation side. At the same time, the current judgment criteria should meet the small current grounding fault analysis. The locking standby automatic transfer function module has the functions of incoming line and section standby automatic transfer locking, busbar protection and fault busbar identification, and is equipped with charging overcurrent protection function.

[0071] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A fault self-healing distribution terminal adapted to a new type of power distribution system, wherein the fault self-healing distribution terminal is deployed in a distribution system connected to a distributed power source, wherein the distribution system includes a distributed power source, a distribution automation system and the fault self-healing distribution terminal; characterized in that: The fault self-healing distribution terminal is equipped with a data transmission unit DTU; the fault self-healing distribution terminal is connected to the distribution automation system, the distribution automation system is connected to the dispatching automation system, and the dispatching automation system is connected to the low-frequency and low-voltage load reduction device; After the low-frequency and low-voltage load shedding device is actuated, the low-frequency and low-voltage load shedding action signal is uploaded to the dispatching automation system, the dispatching automation system sends the low-frequency and low-voltage load shedding action signal to the distribution automation system, and finally the distribution automation system sends the low-frequency and low-voltage load shedding action signal to the data transmission unit in the fault self-healing distribution terminal; the distribution automation system includes a SCADA system; The fault self-healing distribution terminal is configured as: Receive the alarm signal sent by the SCADA system, generate a control signal according to the access status of the distributed power source, and transmit the control signal to the switchgear in the power system; the fault self-healing distribution terminal locks the fault self-healing function of the distribution automation system during the generation of the control signal; the alarm signal is generated by the SCADA system according to the outgoing circuit breaker trip signal generated by the power system; as well as, Receive the remote control command of the distribution automation system and transmit it to the standby automatic switch, so that the standby automatic switch performs corresponding actions in response to the remote control command; the remote control command is generated and issued by the distribution automation system when the distribution automation system monitors that the standby automatic switch refuses to operate or fails to execute the action; The fault self-healing distribution terminal does not receive remote control instructions from the distribution automation system during the generation of the control signal; The method for generating a control signal by a fault self-healing power distribution terminal includes: Determine whether a low-frequency and low-voltage load shedding action signal is received, if so, lock the standby automatic transfer, otherwise execute the next step; Determine whether a low-frequency and low-voltage load shedding action signal is received, to determine whether there is a low-frequency and low-voltage load shedding action signal in the data transmission unit; According to the alarm signal, determine whether the fault section is the incoming section or the bus section. When the fault section is the incoming section, or when the fault section is the bus section and the fault load has been isolated, perform corresponding actions on the backup automatic switch according to the access status of the distributed power source; The performing corresponding actions on the backup automatic switch according to the access status of the distributed power source includes: Determine whether the distributed power source is connected. If not, directly enable the backup automatic switch. Otherwise, according to the relationship between the connected distributed power source and the load, first process the load or distributed power source, and then enable the backup automatic switch, including: If the output of the distributed power source is less than the load, the synchronous device will be used to cut off part of the load, and then the backup automatic transfer will be enabled; if the output of the distributed power source is greater than the load, the distributed power source will be completely cut off, and then the backup automatic transfer will be enabled.

2. The fault self-healing distribution terminal adapted to the new power distribution system according to claim 1, characterized in that: When the fault occurs in the busbar section and the fault load has been isolated, the backup automatic switch is operated according to the distributed power supply access situation, including: When the fault occurs in the busbar section, determine whether the faulty load has been isolated. If so, perform corresponding actions on the standby automatic switch according to the distributed power supply access situation. If the faulty load has not been isolated, wait until the faulty load is isolated, and then perform corresponding actions on the standby automatic switch according to the distributed power supply access situation, and lock the standby automatic switch during the waiting period.

3. The fault self-healing distribution terminal adapted to the new power distribution system according to claim 1, characterized in that: When determining whether a low-frequency and low-voltage load shedding action signal is received, if no low-frequency and low-voltage load shedding action signal is received within a preset time interval, the next step is executed.

4. The fault self-healing distribution terminal adapted to the new power distribution system according to claim 1, characterized in that: The fault self-healing distribution terminal includes a small current grounding fault analysis module, a circuit breaker failure protection module, and a locking standby automatic transfer function module, and the control signal is generated by the locking standby automatic transfer function module.

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