Dynamic acceleration zero-current protection method for subway medium-voltage looped network power supply

Abstract

The invention discloses a dynamic acceleration zero-current protection method for power supply of a medium-voltage ring network of a subway. The method comprises the following steps: acquiring a first current starting signal sent by an incoming and outgoing line of the same bus and a bus coupler device, a second current starting signal sent by an incoming and outgoing line device on the opposite side and a zero-sequence current of a protection device on the side; when the dynamic acceleration zero-current protection is started and a first current starting signal does not exist, a circuit breaker corresponding to a protection device on the side is controlled to perform delay action tripping on the dynamic acceleration zero-current bus protection T1, and meanwhile, a shunt tripping bus side outlet is driven to be used for shunt tripping of the same bus incoming and outgoing line circuit breaker and a bus tie circuit breaker; and when the dynamic acceleration zero-current protection is started and the second current starting signal does not exist, controlling the circuit breaker corresponding to the protection device at the side to perform delay action tripping at the dynamic acceleration zero-current line protection T1, and simultaneously driving a shunt tripping opposite-side outlet for shunt tripping of the opposite-side line circuit breaker. On the basis of a current starting comparison principle, a looped network cable fault and a bus fault are automatically identified, and a single-phase grounding fault is rapidly removed.

Description

Technical Field

[0001] The invention relates to the technical field of subway power supply protection, and in particular to a dynamic accelerated zero-current protection method for subway medium-voltage ring network power supply. Background Art

[0002] In order to ensure the reliability of power supply, the 35kV medium voltage network of the subway generally adopts a ring network system for power supply. Both the main substation and the sub-substation adopt a single busbar segmented wiring form, and introduce two power supplies from the upper substation.

[0003] Under normal circumstances, the interconnecting switches between the main substations are disconnected, and each main substation operates independently, each bearing all traction and power lighting loads within its power supply range; the two main transformers in the substation operate separately, each introducing a 110kV power line from the local power grid, and after voltage reduction, each feeds a medium-voltage power line to the lower-level substation. The busbar of each station substation is disconnected, and the two busbars each introduce a medium-voltage power line from the main substation or the adjacent substation to supply power to the distribution transformer and rectifier unit of the substation.

[0004] For medium voltage systems with a neutral point grounded by a small resistor, single-phase grounding faults are prone to occur. When a fault occurs, the zero-sequence current value of the fault line is large, while the zero-sequence current value of the non-fault line is very small. The method of using zero-sequence current protection to judge single-phase grounding faults is very reliable and effective. The removal of single-phase grounding faults generally adopts a fixed extension time, which results in a relatively long time for the entire protection action. For faults with many grounding fault pulses or long pulse widths in a short period of time, the fault may be expanded into a phase-to-phase grounding fault because the fault cannot be removed quickly, causing the fault to expand. Therefore, how to quickly remove a single-phase grounding fault is a problem that needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a subway medium-voltage ring network power supply dynamic acceleration zero-current protection method, which automatically identifies ring network cable faults and busbar faults based on the current starting comparison principle and quickly cuts off single-phase grounding faults.

[0006] In order to achieve the above object, the scheme of the present invention is:

[0007] The present application provides a method for dynamically accelerating zero-current protection of a subway medium-voltage ring network power supply, including:

[0008] Obtain the first GOOSE input signal sent from the same busbar incoming and outgoing lines and the bus tie device, the second GOOSE input signal sent from the opposite incoming and outgoing line device, and the zero-sequence current of the protection device on this side;

[0009] According to the zero-sequence current of the protection device on this side, it is judged whether the dynamic acceleration zero-current protection of the protection device on this side is started;

[0010] Identify whether there is a first current start signal in the same busbar incoming and outgoing line device and the bus coupling device according to the first GOOSE input signal;

[0011] Identify whether there is a second current start signal in the opposite side incoming and outgoing line device according to the second GOOSE input signal;

[0012] When the dynamic acceleration zero-current protection is started and there is no first current start signal, it is identified as a bus fault, and the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current bus protection T1 delay action, and at the same time drive the bus side outlet to trip the same bus incoming and outgoing line circuit breakers and bus tie circuit breakers;

[0013] When the dynamic acceleration zero-current protection is started and there is no second current starting signal, it is identified as a ring network cable fault, and the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current line protection T1 delay action, and at the same time drive the opposite side outlet to trip the opposite side line circuit breaker.

[0014] In some specific implementations, the first GOOSE input signal includes a GOOSE communication bus side current start, a GOOSE communication bus side device failure, a GOOSE communication bus side link abnormality,

[0015] When no GOOSE communication bus side current start is received and no GOOSE communication bus side device failure is received, and the GOOSE communication bus side link is abnormal, the communication channel between the protection device on this side and the bus incoming and outgoing line device and the bus coupling device is normal, then it is recognized that there is no first current start signal on the bus incoming and outgoing line device and the bus coupling device.

[0016] In some specific embodiments, when a GOOSE communication bus side device fault or a GOOSE communication bus side link abnormality is received, the communication channel between the protection device on this side and the bus incoming and outgoing line device and the bus coupling device is abnormal. If the dynamic acceleration zero-current protection is started and a GOOSE communication bus side device fault or a GOOSE communication bus side link abnormality is received, the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current bus protection T2 delay action.

[0017] In some specific embodiments, when the dynamic acceleration zero-current protection is activated and the communication channel between the side protection device and the busbar inlet and outlet device and the bus coupling device is abnormal, it also includes controlling the protection device on this side to lock the standby automatic transfer outlet.

[0018] In some specific embodiments, when the dynamic acceleration zero-current protection is activated and there is no first current starting signal, it also includes controlling the protection device on this side to lock the backup automatic transfer outlet.

[0019] In some specific implementations, the second GOOSE input signal includes the current start-up on the GOOSE communication opposite side, the failure of the GOOSE communication opposite side incoming and outgoing line device, and the abnormality of the GOOSE communication opposite side link.

[0020] When the current start signal from the opposite side of GOOSE communication is not received and the incoming and outgoing line device failure and the link of the opposite side of GOOSE communication are not received, and the communication channel between the protection device on this side and the incoming and outgoing line device on the opposite side is normal, it is recognized that there is no second current start signal from the incoming and outgoing line device on the same opposite side.

[0021] In some specific embodiments, when a GOOSE communication opposite side incoming and outgoing line device fault or GOOSE communication opposite side link abnormality is received, the communication channel between the protection device on this side and the opposite side incoming and outgoing line device is abnormal. If the dynamic acceleration zero-current protection is activated and a GOOSE communication opposite side incoming and outgoing line device fault or GOOSE communication opposite side link abnormality is received, the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current line protection T2 delay action.

[0022] In some specific implementations, a method for judging whether the dynamic acceleration zero-current protection of the protection device on this side is started according to the zero-sequence current of the protection device on this side is:

[0023] Determine whether the zero-sequence current I0:3I0 is greater than the dynamic acceleration zero-current setting value. If it is greater, it is determined that the dynamic acceleration zero-current protection is started.

[0024] In some specific implementations, if the circuit breaker corresponding to the protection device on this side does not operate during the dynamic acceleration zero-current protection delay T1 and T2, the circuit breaker corresponding to the protection device on this side is controlled to trip during the dynamic acceleration zero-current protection delay T3.

[0025] The present invention has the beneficial effects:

[0026] The present invention is used to cut off single-phase grounding faults. The dynamic acceleration protection is based on the current starting signal comparison principle. It realizes full coverage, step-free, highly selective and rapid protection of the ring network cables and busbars in the subway ring network power supply system. The protection has the characteristics of automatically identifying ring network cable faults and busbar faults, and is not affected by changes in the power supply direction.

[0027] For the large-area operating conditions of multiple substations in the subway power supply system, the setting of protection settings does not require differential coordination, and all devices can use a set of settings. Dynamic acceleration protection can be used as the main protection for busbar protection, and can also be used as a fast backup protection for line fiber optic differential protection. When the fiber optic channel is normal and all protection devices are fault-free, dynamic acceleration protection can quickly cut off the fault during the T1 delay. When the fiber optic channel is damaged or a single device fails, the dynamic acceleration protection automatically locks the protection T1 delay and can quickly cut off the fault during the T2 delay. Dynamic acceleration protection has the characteristics of automatically identifying ring network cable faults and busbar faults. It can also isolate faults through device linkage and coordination, and can quickly start the next level of busbar backup to realize load transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the logic of the dynamic acceleration zero-current protection action provided by an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of the dynamic acceleration zero-current protection tripping logic provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of 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, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. 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.

[0031] The relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0032] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0033] Additionally, descriptions of well-known structures, functions, and configurations may be omitted for clarity and conciseness.One of ordinary skill in the art will recognize that various changes and modifications may be made to the examples described herein without departing from the spirit and scope of the present disclosure.

[0034] Technologies, methods, and apparatus known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, such technologies, methods, and apparatus should be considered part of the authorization specification.

[0035] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0036] Example 1

[0037] This embodiment provides a method for dynamically accelerating zero-current protection of a subway medium-voltage ring network power supply, including:

[0038] Obtain the first GOOSE input signal sent from the same busbar incoming and outgoing lines and the bus tie device, the second GOOSE input signal sent from the opposite incoming and outgoing line device, and the zero-sequence current of the protection device on this side;

[0039] According to the zero-sequence current of the protection device on this side, it is judged whether the dynamic acceleration zero-current protection of the protection device on this side is started;

[0040] Identify whether there is a first current start signal in the same busbar incoming and outgoing line device and the bus coupling device according to the first GOOSE input signal;

[0041] Identify whether there is a second current start signal in the opposite side incoming and outgoing line device according to the second GOOSE input signal;

[0042] When the dynamic acceleration zero-current protection is started and there is no first current starting signal, it is identified as a bus fault, and the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current bus protection T1 delayed action, and at the same time drive the bus side outlet to trip the same bus incoming and outgoing line circuit breakers and the bus tie circuit breaker; at the same time, when the dynamic acceleration zero-current protection is started and there is no first current starting signal, it also includes controlling the protection device on this side to lock the standby automatic transfer outlet.

[0043] When the dynamic acceleration zero-current protection is started and there is no second current starting signal, it is identified as a ring network cable fault, and the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current line protection T1 delay action, and at the same time drive the opposite side outlet to trip the opposite side line circuit breaker.

[0044] Specifically, the first GOOSE input signal includes the current start-up on the GOOSE communication bus side, the device failure on the GOOSE communication bus side, and the link abnormality on the GOOSE communication bus side.

[0045] When no GOOSE communication bus side current start is received and no GOOSE communication bus side device failure is received, and the GOOSE communication bus side link is abnormal, the communication channel between the protection device on this side and the bus incoming and outgoing line device and the bus coupling device is normal, then it is recognized that there is no first current start signal on the bus incoming and outgoing line device and the bus coupling device.

[0046] When the communication channel between the protection device on this side and the busbar inlet and outlet device and the bus coupling device is abnormal, the GOOSE communication busbar side device fault or GOOSE communication busbar side link is received. At this time, if the dynamic acceleration zero-current protection is started and the GOOSE communication busbar side device fault or GOOSE communication busbar side link is received, the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current busbar protection T2 delay action. When the dynamic acceleration zero-current protection is started and the communication channel between the side protection device and the busbar inlet and outlet device and the bus coupling device is abnormal, it also includes controlling the protection device on this side to lock the standby automatic throw-in outlet.

[0047] In some specific implementations, the second GOOSE input signal includes the current start-up on the GOOSE communication opposite side, the failure of the GOOSE communication opposite side incoming and outgoing line device, and the abnormality of the GOOSE communication opposite side link.

[0048] When the current start signal from the opposite side of GOOSE communication is not received and the incoming and outgoing line device failure and the link of the opposite side of GOOSE communication are not received, and the communication channel between the protection device on this side and the incoming and outgoing line device on the opposite side is normal, it is recognized that there is no second current start signal from the incoming and outgoing line device on the same opposite side.

[0049] When the communication channel between the protection device on this side and the incoming and outgoing line device on the opposite side is abnormal, the GOOSE communication incoming and outgoing line device fault on the opposite side and the GOOSE communication link abnormal input signal will be received. At this time, if the dynamic acceleration zero-current protection is started and the GOOSE communication incoming and outgoing line device fault on the opposite side or the GOOSE communication link abnormality is received, the circuit breaker corresponding to the protection device on this side will be controlled to trip in the dynamic acceleration zero-current line protection T2 delay action.

[0050] Specifically, the method for judging whether the dynamic acceleration zero-current protection of the protection device on this side is started according to the zero-sequence current of the protection device on this side is:

[0051] Determine whether the zero-sequence current I0:3I0 is greater than the dynamic acceleration zero-current setting value. If it is greater, it is determined that the dynamic acceleration zero-current protection is started.

[0052] As backup protection, when the circuit breaker corresponding to the protection device on this side does not operate during the dynamic acceleration zero-current protection T1 delay and T2 delay, the circuit breaker corresponding to the protection device on this side is controlled to trip during the dynamic acceleration zero-current protection T3 delay.

[0053] It is understandable that the dynamic acceleration zero current protection is mainly used to cut off the single-phase grounding fault. Its action logic and tripping logic are as follows: Figure 1 and Figure 2 shown.

[0054] The zero-sequence current in this embodiment can be self-generated or introduced from the zero-sequence CT of the device. The control word "self-generated zero-sequence current" is set to "0" to indicate that the zero-sequence current used by the device is externally applied, and is set to "1" to indicate that the zero-sequence current used by the device is self-generated. When the zero-sequence current is self-generated, the protection is locked by the "CT abnormal alarm".

[0055] like Figure 1 As shown in the figure, the action logic of dynamic acceleration zero current protection is as follows: When the local protection device detects three times of zero sequence current I0, that is, 3I0 is greater than the "dynamic acceleration zero current setting value", the dynamic acceleration zero current protection is activated.

[0056] When the dynamic acceleration zero-current protection is activated, the communication channel between the protection device on this side and the incoming and outgoing line device on the opposite side is normal, and there is no current start signal from the incoming and outgoing line device on the opposite side, it is identified as a ring network cable fault, and the dynamic acceleration zero-current protection is delayed by T1;

[0057] When the dynamic acceleration zero-current protection is started, the communication channel between the protection device on this side and the bus incoming and outgoing line device and the bus coupling device is normal, and there is no current starting signal on the same bus incoming and outgoing line device and the bus coupling device, it is identified as a bus fault, and the dynamic acceleration zero-current protection also acts after T1 delay.

[0058] The dynamic acceleration zero-current protection T2 delay is only activated under abnormal conditions when the protection device on this side cannot correctly receive the current start signal of other devices, and the T1 delay is locked at the same time. There are two types of abnormal conditions. One is the inability to correctly receive the current start signal of the opposite line device due to abnormal communication on the opposite side and failure of the opposite incoming and outgoing line device. The other is the inability to receive the current start signal due to failure of the same bus incoming and outgoing line, bus coupling device or power failure of the device. The dynamic acceleration zero-current protection T3 delay serves as a backup protection and is fixedly delayed. The current start signals received by the protection device on this side are divided into two categories, one is from the opposite line device, and the other is from the same bus incoming and outgoing line and bus coupling device.

[0059] like Figure 2 As shown, the tripping logic is: any time-limited action of the dynamic acceleration zero-current protection (dynamic acceleration zero-current T3 action, dynamic acceleration zero-current bus T2 action, dynamic acceleration zero-current line T2 action, dynamic acceleration zero-current bus T1 time-limited action, dynamic acceleration zero-current line T1 time-limited action) will trip the interval circuit breaker of the protection device on this side.

[0060] When the dynamic acceleration of the zero-current bus T1 time limit action is performed, the bus side outlet is driven to trip simultaneously, which is used to trip the incoming and outgoing line circuit breakers and the bus tie circuit breaker on the same bus; the dynamic acceleration of the zero-current line T1 time limit action is performed, and the opposite side outlet is driven to trip simultaneously, which is used to trip the opposite side line circuit breaker.

[0061] When the dynamic acceleration zero-current bus T1 or T2 time limit is actuated, the standby automatic switching outlet is locked at the same time;

[0062] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. According to the technical essence of the present invention, within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for dynamically accelerating zero-current protection of a subway medium-voltage ring network power supply, characterized in that: include: Obtain the first GOOSE input signal sent from the same busbar incoming and outgoing lines and the bus tie device, the second GOOSE input signal sent from the opposite incoming and outgoing line device, and the zero-sequence current of the protection device on this side; According to the zero-sequence current of the protection device on this side, it is judged whether the dynamic acceleration zero-current protection of the protection device on this side is started; Identify whether there is a first current start signal in the same busbar incoming and outgoing line device and the bus coupling device according to the first GOOSE input signal; Identify whether there is a second current start signal in the opposite side incoming and outgoing line device according to the second GOOSE input signal; When the dynamic acceleration zero-current protection is started and there is no first current start signal, it is identified as a bus fault, and the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current bus protection T1 delay action, and at the same time drive the bus side outlet to trip the same bus incoming and outgoing line circuit breakers and bus tie circuit breakers; When the dynamic acceleration zero-current protection is started and there is no second current starting signal, it is identified as a ring network cable fault, and the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current line protection T1 delay action, and at the same time drive the opposite side outlet to trip the opposite side line circuit breaker.

2. The method for dynamic acceleration of zero-current protection of subway medium-voltage ring network power supply according to claim 1 is characterized in that: The first GOOSE input signal includes the current start of the GOOSE communication bus side, the device failure of the GOOSE communication bus side, and the link abnormality of the GOOSE communication bus side. When no GOOSE communication bus side current start is received and no GOOSE communication bus side device failure is received, and the GOOSE communication bus side link is abnormal, the communication channel between the protection device on this side and the bus incoming and outgoing line device and the bus coupling device is normal, then it is recognized that there is no first current start signal on the bus incoming and outgoing line device and the bus coupling device.

3. The method for dynamic acceleration of zero-current protection of subway medium-voltage ring network power supply according to claim 2 is characterized in that: When a GOOSE communication bus side device fault or GOOSE communication bus side link abnormality is received, the communication channel between the protection device on this side and the bus incoming and outgoing line device and the bus coupling device is abnormal. If the dynamic acceleration zero-current protection is started and a GOOSE communication bus side device fault or GOOSE communication bus side link abnormality is received, the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current bus protection T2 delay action.

4. The method for dynamic acceleration of zero-current protection of subway medium-voltage ring network power supply according to claim 3 is characterized in that: When the dynamic acceleration zero-current protection is activated and the communication channel between the side protection device and the busbar inlet and outlet device and the bus coupling device is abnormal, it also includes controlling the protection device on this side to lock the standby automatic transfer outlet.

5. The method for dynamic acceleration of zero-current protection of subway medium-voltage ring network power supply according to claim 1 is characterized in that: When the dynamic acceleration zero-current protection is activated and there is no first current starting signal, it also includes controlling the protection device on this side to lock the standby automatic transfer outlet.

6. The method for dynamic acceleration of zero-current protection of subway medium-voltage ring network power supply according to claim 1 is characterized in that: The second GOOSE input signal includes the current start of the GOOSE communication opposite side, the failure of the GOOSE communication opposite side incoming and outgoing line device, and the abnormality of the GOOSE communication opposite side link. When the current start signal from the opposite side of GOOSE communication is not received and the incoming and outgoing line device failure and the link of the opposite side of GOOSE communication are not received, and the communication channel between the protection device on this side and the incoming and outgoing line device on the opposite side is normal, it is recognized that there is no second current start signal from the incoming and outgoing line device on the same opposite side.

7. The method for dynamic acceleration of zero-current protection of subway medium-voltage ring network power supply according to claim 6 is characterized in that: When the GOOSE communication receives a signal that the incoming and outgoing line device on the opposite side is faulty or the GOOSE communication link on the opposite side is abnormal, the communication channel between the protection device on this side and the incoming and outgoing line device on the opposite side is abnormal. If the dynamic acceleration zero-current protection is activated and the GOOSE communication receives a signal that the incoming and outgoing line device on the opposite side is faulty or the GOOSE communication link on the opposite side is abnormal, the circuit breaker corresponding to the protection device on this side is controlled to trip in the dynamic acceleration zero-current line protection T2 delay action.

8. The method for dynamic acceleration of zero-current protection of subway medium-voltage ring network power supply according to claim 1 is characterized in that: The method for judging whether the dynamic acceleration zero-current protection of the protection device on this side is started according to the zero-sequence current of the protection device on this side is: Determine whether the zero-sequence current I0:3I0 is greater than the dynamic acceleration zero-current setting value. If it is greater, it is determined that the dynamic acceleration zero-current protection is started.

9. The method for dynamic acceleration of zero-current protection of subway medium-voltage ring network power supply according to claim 8, characterized in that: If the circuit breaker corresponding to the protection device on this side does not operate during the dynamic acceleration zero-current protection T1 delay and T2 delay, the circuit breaker corresponding to the protection device on this side will be controlled to trip during the dynamic acceleration zero-current protection T3 delay.

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