Busbar protection device

Abstract

This application proposes a busbar protection device comprising: a digital input module, the input of which is connected to the actuation output contact of a main transformer protection device, the output signal of which serves as the first switching input signal of the device; and a control module, connected to the output of the digital input module. The control module generates a trip signal based on the first switching input signal and preset trip logic, and controls the tripping of each circuit breaker connected to the busbar according to the trip signal. This device solves the technical problems of cumbersome wiring and the need for a large number of expanded protection actuation outputs in the prior art.

Description

Technical Field

[0001] The present application relates to the technical field of busbar protection, and in particular to a busbar protection device. Background Art

[0002] In early wind farm booster stations, the busbar on the low-voltage side (35kV) of the main transformer served as the wind turbine busbar. Typically, a circuit breaker is installed on the low-voltage side of the main transformer. When a main transformer fault occurs, the main transformer protection trips the circuit breakers on both sides of the main transformer, clearing the fault and removing the wind turbine busbar from operation. However, the operating principles of the wind turbine busbar at current wind farm booster stations differ from this conventional approach. Because each wind turbine has both low-voltage ride-through and high-voltage ride-through capabilities, and because this section of busbar is also connected to devices such as dynamic reactive power compensation (SVG), electrochemical energy storage devices, and even small phase-shifting devices, voltage remains on this section of busbar for a period of time after the main transformer's low-voltage side circuit breaker trips. This situation poses a safety hazard to the operation and maintenance of the 35kV busbar.

[0003] In order to change this situation and eliminate safety hazards, the secondary design of the wind farm booster station is required to do the following: (1) In addition to tripping the circuit breakers on each side, the protection action output of the main transformer of the wind farm booster station is also required to trip all circuit breakers on the low-voltage side busbar of the main transformer (the wind turbine collection busbar). (2) The low-resistance grounding system protection action output on the low-voltage side busbar of the main transformer of the wind farm booster station (the wind turbine collection busbar) is required to trip all circuit breakers on this section of the busbar. (3) The low-resistance grounding system protection action output on the wind turbine collection busbar of the wind farm switch station is required to trip all circuit breakers on this section of the busbar.

[0004] Although the buses described in (1), (2) and (3) above are all equipped with busbar protection, the current busbar protection devices of this type are equipped with busbar differential protection, busbar overcurrent protection, busbar non-full-phase protection, busbar dead zone protection, busbar failure protection and main transformer tripping via busbar differential tripping function. However, these functions are only applicable to the main transformer high-voltage side busbar, and although a few devices have the main transformer low-voltage busbar tripping function, it is only a simple input quantity judgment and cannot be applied to the actual needs of wind farm booster stations (photovoltaic power plant booster stations). Due to the low voltage level of the protected busbar (generally 10kV, 35kV or 66kV), it does not have the function of linkage with other protection devices and the required judgment function. Therefore, to achieve the above (1), (2) and (3), on the one hand, it will lead to complicated secondary wiring of the booster station, too many cables, large installation and debugging workload, and increase unnecessary engineering costs. On the other hand, from the perspective of the protection equipment manufacturer, it is necessary to expand the action output contacts of the corresponding main transformer protection device and low-resistance grounding system protection device in large quantities, and the product production cost is high. Summary of the Invention

[0005] The present application aims to solve one of the technical problems in the related art at least to a certain extent.

[0006] To this end, the purpose of this application is to propose a busbar protection device to simplify the secondary wiring of the wind farm booster station (photovoltaic farm booster station) and reduce engineering costs, and to solve the technical problems in related technologies such as complicated wiring, the use of a large number of cables, and the need for a large number of expanded action output contacts of related protection devices.

[0007] To achieve the above objectives, the present application provides a busbar protection device, comprising:

[0008] a digital input module, wherein an input end of the digital input module is connected to an action output contact of the main transformer protection device, and an output signal of the action output contact of the main transformer protection device serves as a first switching input signal of the device;

[0009] A control module is connected to the output end of the digital input module, and the control module obtains a trip signal according to the first switch input signal and a preset trip logic, and controls the tripping of each circuit breaker connected to the bus according to the trip signal.

[0010] In some implementations, the input end of the digital input module is further connected to an action output contact of a low-resistance grounding system protection device, and an output signal of the action output contact of the low-resistance grounding system protection device serves as a second switching input signal of the device;

[0011] The control module also obtains a trip signal according to the second switch input signal and a preset trip logic, and controls the tripping of each circuit breaker connected to the bus according to the trip signal.

[0012] In some implementations, an intermediate relay is provided between the input end of the digital input module and the action output contact of the main transformer protection device, and an intermediate relay is provided between the input end of the digital input module and the action output contact of the low-resistance grounding system protection device.

[0013] In some implementations, the control unit is further configured to control a delay time for tripping each circuit breaker connected to the bus according to a preset value setting table.

[0014] In some implementations, the preset trip logic includes a voltage on a secondary side of a voltage transformer of the bus.

[0015] In some implementations, the preset jump logic includes:

[0016] When the first switching input signal and the voltage on the secondary side of the voltage transformer of the busbar simultaneously meet preset conditions, a joint trip signal is obtained.

[0017] In some implementations, the digital input module uses DC 220V as a control power supply.

[0018] The busbar protection device provided by the present application increases the interface for coordination between the busbar protection device and the main transformer protection through a digital input module, thereby realizing the function of external protection linkage with the circuit breaker on this section of the busbar. This makes the electrical secondary design protection configuration scheme of the new energy station reasonable, the secondary wiring simple, and there is no need to expand a large number of protection action outlets, which reduces the project cost; it also makes the operation and maintenance of the new energy station safer, more reliable and more convenient. It solves the current cumbersome secondary wiring problem of wind farm booster stations, and brings cost-saving benefits to protection equipment manufacturers. At the same time, it makes the protection and monitoring system operation, operation and maintenance of the wind turbine busbar of the wind farm booster station more reliable, safe and convenient.

[0019] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0021] Figure 1 This is a functional logic diagram of the main transformer protection action tripping each circuit breaker of the bus section provided in an embodiment of the present application;

[0022] Figure 2 This is a functional logic diagram of the low-resistance grounding system protection action provided by an embodiment of the present application, which trips each circuit breaker of the bus section;

[0023] Figure 3 This is a wiring diagram of the input end of the digital input module provided in an embodiment of the present application.

[0024] Figure 4 This is a functional logic diagram of the main transformer protection action tripping each circuit breaker of the bus section provided by another embodiment of the present application;

[0025] Figure 5 This is a functional logic diagram of the low-resistance grounding system protection action tripping each circuit breaker in this section of the bus provided by another embodiment of the present application. DETAILED DESCRIPTION

[0026] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0027] To mitigate safety hazards, current wind farm booster stations require complex secondary wiring and a significant expansion of tripping contacts. Taking the secondary wiring of a medium-sized wind farm booster station as an example, the main transformer protection device has 30 pairs of tripping contacts, including 12 standard sets (7 for high-voltage, low-voltage, busbar differential, failure, fire protection, and backup). Busbar section I requires 15 circuit breakers to trip, so the main transformer protection device requires eight additional tripping contacts to ensure that all circuit breakers on the low-voltage bus are tripped upon main transformer protection activation. If redundant main transformer protection is used, the other main transformer protection panel also needs to have the same number of tripping contacts. Main transformer protection panel A provides 15 additional control cables, each connected to 15 corresponding 35kV switchgear panels. Main transformer protection panel B provides 15 additional control cables, each connected to 15 corresponding 35kV switchgear panels. Six heavy-duty, fast-acting relays and 21 corresponding circuit switchers were added to the low-resistance grounding system protection outputs on bus section I to meet the requirement of expanding the low-resistance grounding system protection outputs to include the ability to trip all circuit breakers on the low-voltage bus. Fifteen additional control cables were drawn from the cabinet housing the low-resistance grounding system protection device, each connected to 15 corresponding 35kV switchgear cabinets.

[0028] From the above example analysis, it can be seen that the shortcomings of current busbar protection devices include: 1) The external wiring of the protection device (panel) is cumbersome; 2) There are too many relays and protection action outputs added in the protection device (panel); 3) The reliability of the overall protection system is relatively reduced; 4) After the main transformer protection is activated, other circuit breakers outside its protection range are tripped, and the coordination of various levels of protection devices is unreasonable; 4) Operation and maintenance are extremely inconvenient.

[0029] For wind farm booster stations (photovoltaic power plant booster stations), when the upper-level main transformer protection or the low-resistance ground fault protection on the bus section trips, not only the low-voltage circuit breaker on the main transformer on the bus section trips, but all other circuit breakers on the bus section must also trip. This mismatch between the main transformer protection and the 35kV busbar protection levels can lead to over-tripping. Furthermore, the main transformer protection device requires a significant expansion of its protection outputs, increasing manufacturing costs for the previously safe main transformer protection device. The low-resistance ground fault system protection device requires the addition of fast intermediate relays to expand its protection outputs, further increasing manufacturing costs. From an engineering perspective, this adds unnecessary cabling between the main transformer protection device and other switchgear on the 35kV bus section, increasing cable usage and complicating the secondary wiring design. The addition of cabling between the low-resistance ground fault system protection device and all circuit breaker switchgear on the 35kV bus section also increases cable usage and complicates the secondary wiring design.

[0030] In order to solve at least one of the above problems, an embodiment of the present application provides a busbar protection device.

[0031] The following describes the tripping function of the busbar protection device of the embodiment of the present application with reference to the accompanying drawings.

[0032] The busbar protection device provided in the embodiment of the present application includes a digital input module and a control module.

[0033] Among them, the digital input module, the input end of the digital input module is connected to the action output contact of the main transformer protection device, and the output signal of the action output contact of the main transformer protection device is used as the first switching input signal of the device.

[0034] A control module is connected to the output end of the digital input module, and the control module obtains a trip signal according to the first switch input signal and a preset trip logic, and controls the tripping of each circuit breaker connected to the bus according to the trip signal.

[0035] In some embodiments, a digital input module (DI module) is added to the standard busbar protection device, and the action output contact of the main transformer protection device is connected as the switch input of the busbar protection device through the digital input module to trip the busbar circuit breakers.

[0036] Exemplarily, the DI module includes 8 input points.

[0037] This will completely eliminate the cumbersome secondary wiring issues of existing main transformer protection systems in new energy stations, reduce the workload of designers, and reduce the number of control cables and on-site construction workload.

[0038] The busbar protection device of the embodiment of the present application increases the interface for the busbar protection device to cooperate with the main transformer protection through the digital input module, realizing the function of external protection linkage with the circuit breaker on this section of the busbar. This makes the electrical secondary design protection configuration scheme of the wind farm and photovoltaic power generation station reasonable, the secondary wiring is simple, and there is no need to expand a large number of protection action outlets, which reduces the project cost; it also makes the operation and maintenance of new energy stations safer, more reliable and more convenient. It is suitable for 35kV busbar protection of wind farm booster stations, and is also suitable for photovoltaic power generation project booster stations (switch stations), and is also suitable for 66kV busbars of new energy stations.

[0039] In some embodiments, the input end of the digital input module is further connected to an action output contact of a low-resistance grounding system protection device, and an output signal of the action output contact of the low-resistance grounding system protection device serves as a second switching input signal of the device;

[0040] The control module also obtains a trip signal according to the second switch input signal and a preset trip logic, and controls the tripping of each circuit breaker connected to the bus according to the trip signal.

[0041] That is to say, through the digital input module, the action output contact of the low-resistance grounding system protection device is connected as the switch input of the busbar protection device to trip the busbar circuit breakers.

[0042] This eliminates the need for additional fast intermediate relays to re-operate and expand protection outputs for low-resistance grounding system protection, eliminating potential hazards that could affect the long-term safe and stable operation of protection devices and reducing on-site commissioning workload. For station maintenance personnel, this also reduces the workload of routine inspections, inspections, and repairs.

[0043] In some embodiments, the control unit is further used to control the delay time of tripping each circuit breaker connected to the bus according to a preset value setting table.

[0044] Therefore, the jump delay setting is increased for users to adjust.

[0045] It should be noted here that two types of busbar protection devices can be implemented according to the inter-trip logic, that is, without using the AC quantity criterion and that with using the AC quantity criterion.

[0046] For example, Figure 1 、 2 As shown, it is a schematic diagram of the main transformer protection action of the busbar protection device whose tripping logic does not use AC quantity judgment to trip the functions of each circuit breaker in this section of the busbar, and the low-resistance grounding system protection action to trip the functions of each circuit breaker in this section of the busbar.

[0047] For example, a table for setting the function settings of the circuit breakers on the busbar section that triggers the main transformer protection to trip is added, as shown in Table 1-1. A table for setting the function settings of the circuit breakers on the busbar section that triggers the low-resistance grounding system protection to trip is added, as shown in Table 1-2. The busbar protection has been updated with new setting names, units, and setting ranges. The busbar protection device in this embodiment has a continuously adjustable setting range of 0.03 to 10 seconds.

[0048] Table 1-1 Busbar protection device adds main transformer protection action tripping delay

[0049]

[0050] Table 1-2 Busbar protection device adds low resistance grounding system protection action tripping delay

[0051]

[0052] In some embodiments, the digital input module uses DC 220V as a control power supply.

[0053] In some embodiments, an intermediate relay is provided between the input terminal of the digital input module and the actuation output contact of the main transformer protection device, and an intermediate relay is provided between the input terminal of the digital input module and the actuation output contact of the low-resistance grounding system protection device. A high-power intermediate relay is selected as the intermediate relay.

[0054] Therefore, in order to ensure the reliability of external access switch quantity and avoid electromagnetic interference and other external environmental factors, such as Figure 3 As shown, the DI module uses DC 220V as the control power supply. At the same time, each contact is isolated through a high-power intermediate relay (GKJ1~GKJ3) when it is introduced.

[0055] In some embodiments, the preset trip logic includes a voltage on a secondary side of a voltage transformer of the bus.

[0056] Furthermore, the preset inter-trip logic includes: obtaining an inter-trip signal when the first switching input signal and the voltage on the secondary side of the voltage transformer of the busbar simultaneously meet preset conditions.

[0057] For example, Figure 4 、 5 As shown, the schematic diagram of the bus protection device's tripping logic using AC quantity criteria for the main transformer protection action to trip the functions of each circuit breaker in this section of the bus and the low-resistance grounding system protection action to trip the functions of each circuit breaker in this section of the bus are shown.

[0058] Therefore, by adding a voltage criterion for the busbar protection device to be coordinated with the main transformer protection and the low-resistance grounding system protection, repeated tripping and closing of the circuit breaker on this busbar section can be avoided, thereby extending the service life of the circuit breaker.

[0059] For example, busbar protection devices with busbar voltage criterion have added setting tables for main transformer protection tripping and circuit breaker functions on the bus section (with busbar voltage criterion), as shown in Tables 2-1 and 2-3. Setting tables for low-resistance grounding system protection tripping and circuit breaker functions on the bus section (with busbar voltage criterion) have also been added, as shown in Tables 2-2 and 2-4. Busbar protection has been updated with new setting names, units, and setting ranges. The time setting range for the new busbar protection device, Type II, is continuously adjustable from 0.03 to 10 seconds.

[0060] Table 5-1 Busbar protection adds main transformer protection action trip delay

[0061]

[0062] Table 5-3 Busbar protection adds busbar voltage judgment delay

[0063]

[0064] Table 5-2 Busbar protection adds low resistance grounding system protection action trip delay

[0065]

[0066] Table 5-4 Busbar protection with added low-resistance grounding system protection action delay (with busbar voltage criterion)

[0067]

[0068] The wind farm booster station (switch station) adopts the technical solution disclosed in any of the above embodiments to solve the unreasonable problem of over-tripping of the main transformer protection. The main transformer protection range and the 35kV busbar protection range are reasonably matched, and each performs its own function. The secondary wiring of the wind farm booster station (switch station) is simplified, the repeated laying of control cables is eliminated, and the project cost is reduced; the control operation logic is clear, which can avoid the repeated tripping and closing of the circuit breaker on the 35kV busbar section to the greatest extent, making the operation and maintenance of the wind farm more reliable, safe and convenient. Secondly, the adaptability of the busbar protection device can be improved, and it can be promoted and applied in new energy station projects. The cost of the busbar protection device in the embodiment of the present application is relatively low, and it can be achieved by technical transformation on the basis of the original standard busbar protection device.

[0069] In summary, the adoption of this technical solution by renewable energy sites or projects can fundamentally change the current practice of over-tripping main transformer protection in the renewable energy construction industry. This solution improves and rationalizes the secondary electrical design of wind farms. It also reduces construction costs for renewable energy projects and provides opportunities for relay protection manufacturers to develop new products.

[0070] In the descriptions of the foregoing embodiments, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are mutually inconsistent.

[0071] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0072] In addition, in this application, directional terms such as "upper" and "lower" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they can change accordingly according to changes in the orientation of the components in the drawings.

[0073] In this application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0074] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0075] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0076] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A busbar protection device, characterized in that: The device comprises: a digital input module, wherein an input end of the digital input module is connected to an action output contact of the main transformer protection device, and an output signal of the action output contact of the main transformer protection device serves as a first switching input signal of the device; a control module connected to the output end of the digital input module, the control module obtaining a trip signal according to the first switch input signal and a preset trip logic, and controlling the tripping of each circuit breaker connected to the bus according to the trip signal; The input end of the digital input module is also connected to the action output contact of the low-resistance grounding system protection device, and the output signal of the action output contact of the low-resistance grounding system protection device serves as the second switching input signal of the device; The control module also obtains a trip signal according to the second switch input signal and a preset trip logic, and controls the tripping of each circuit breaker connected to the bus according to the trip signal; The control module is also used to control the delay time of each circuit breaker connected to the bus according to the preset value setting table; The preset inter-trip logic includes the voltage on the secondary side of the voltage transformer of the busbar, and a inter-trip signal is obtained when the first switching input signal and the voltage on the secondary side of the voltage transformer of the busbar simultaneously meet preset conditions.

2. The busbar protection device according to claim 1, characterized in that: An intermediate relay is provided between the input end of the digital input module and the action output contact of the main transformer protection device, and an intermediate relay is provided between the input end of the digital input module and the action output contact of the low-resistance grounding system protection device.

3. The busbar protection device according to claim 1, characterized in that: The digital input module uses DC 220V as the control power supply.

Images