Distributed optical fiber differential protection device of top-mounted boosting transformer of wind turbine generator

Abstract

The utility model discloses a distributed optical fiber differential protection device of an overhead step-up transformer of a wind turbine generator, which relates to the technical field of wind power generation in the new energy industry and comprises a low-voltage circuit breaker, a step-up transformer and a high-voltage circuit breaker which are electrically connected in sequence. The low-voltage circuit breaker is electrically connected with the generator, and the high-voltage circuit breaker is electrically connected with the current collection circuit; the low-voltage current transformer is connected between the low-voltage circuit breaker and the boosting transformer; the high-voltage current transformer is connected between the boosting transformer and the high-voltage circuit breaker; the expansion unit is electrically connected between the low-voltage current transformer and the low-voltage circuit breaker; an optical fiber; the main control unit is electrically connected between the high-voltage current transformer and the high-voltage circuit breaker; the main control unit is used for collecting and comparing the secondary protection current on the two sides of the transformer, so that the differential current on the two sides of the transformer is directly sampled to realize electrical quantity protection.

Description

Technical Field

[0001] The utility model relates to the technical field of wind power generation in the new energy industry, in particular to a distributed optical fiber differential protection device for a top-mounted step-up transformer of a wind turbine generator set. Background Art

[0002] At present, the step-up transformers of onshore wind turbines are mainly floor-mounted and arranged outside the turbines (box-type substations), while large-capacity wind turbines are top-mounted and arranged inside the nacelle (nacelle transformer).

[0003] In the prior art, due to the limited space inside the cabin, it is impossible to install high-voltage circuit breakers, low-voltage circuit breakers, high-voltage current transformers and low-voltage current transformers and other components at the same time, resulting in the transformer being unable to directly sample the differential current on both sides of the transformer to achieve electrical quantity protection. The transformer can only reflect whether there is a fault by monitoring the operating temperature of the transformer. The change of electrical quantities when the transformer fails is faster and more sensitive than the change of temperature quantities. Therefore, the transformer without differential protection brings a certain degree of risk to the safe and stable operation of the wind turbine. Utility Model Content

[0004] In view of this, the utility model provides a distributed optical fiber differential protection device for a wind turbine top-mounted step-up transformer, which collects secondary protection currents of the current transformers at the bottom of the tower and in the nacelle respectively through a main control unit and an extension unit, and then compares the currents on both sides through a communication optical cable laid in the tower, thereby quickly cutting off the faulty transformer from the power system and ensuring the equipment safety of the wind turbine.

[0005] The utility model provides the following technical solution: a distributed optical fiber differential protection device for a wind turbine top-mounted booster transformer, comprising a low-voltage circuit breaker, a booster transformer and a high-voltage circuit breaker electrically connected in sequence; the low-voltage circuit breaker is electrically connected to the generator, and the high-voltage circuit breaker is electrically connected to the collector line; and further comprising:

[0006] a low voltage current transformer, the primary end of which is electrically connected between the low voltage circuit breaker and the step-up transformer;

[0007] An extension unit is electrically connected to the secondary end of the low-voltage current transformer, and is used to obtain the secondary protection current of the low-voltage side of the transformer and realize the conversion between the electrical signal and the optical signal; the extension unit is electrically connected to the low-voltage circuit breaker, and is used to control the low-voltage circuit breaker to break;

[0008] a high-voltage current transformer, a primary end of which is electrically connected between the step-up transformer and the high-voltage circuit breaker;

[0009] An optical fiber, one end of which is connected to the extension unit and is used for bidirectionally transmitting optical signals;

[0010] A main control unit is electrically connected to the secondary end of the high-voltage current transformer to obtain the secondary current on the high-voltage side of the transformer; the main control unit is connected to the other end of the optical fiber to achieve conversion between electrical signals and optical signals; the main control unit is electrically connected to the high-voltage circuit breaker to control the high-voltage circuit breaker to break;

[0011] The low voltage circuit breaker and the low voltage current transformer are arranged in the cabin, and the high voltage current transformer and the high voltage circuit breaker are arranged in the bottom of the tower.

[0012] Furthermore, preferably, the high-voltage current transformer and the main control unit, as well as the low-voltage current transformer and the extension unit are connected via conductors and cables; the main control unit and the high-voltage circuit breaker, as well as the extension unit and the low-voltage circuit breaker are connected via switch control cables.

[0013] Furthermore, as a preference, it also includes an auxiliary winding connected to the conductor and cable between the low-voltage current transformer and the high-voltage current transformer.

[0014] Furthermore, preferably, the input modes of the protection winding and the measurement winding in the low-voltage current transformer and the high-voltage current transformer are both alternating current.

[0015] Furthermore, as a preference, it also includes a monitoring background electrically connected to the main control unit.

[0016] Furthermore, preferably, a plug-in lightning arrester is connected between the high-voltage circuit breaker and the collector line.

[0017] Furthermore, as a preference, a live display is connected between the high-voltage current transformer and the isolating grounding switch, and a display is also connected between the high-voltage circuit breaker and the collector line.

[0018] Compared with the prior art, the utility model provides a distributed optical fiber differential protection device for a wind turbine top-mounted step-up transformer, which has the following beneficial effects:

[0019] The high-voltage circuit breaker and the high-voltage current transformer are installed at the bottom of the tower, and the low-voltage circuit breaker and the low-voltage current transformer are installed in the cabin. The signals of the main control unit and the expansion unit are transmitted through optical fiber to collect and compare the secondary protection currents on both sides of the transformer, thereby directly sampling the differential current on both sides of the transformer to achieve electrical quantity protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the electrical system of a distributed optical fiber differential protection device for a wind turbine top-mounted step-up transformer;

[0021] Figure 2This is a schematic diagram of the principle wiring of the distributed optical fiber differential protection device for the wind turbine top-mounted step-up transformer; DETAILED DESCRIPTION

[0022] The utility model provides a distributed optical fiber differential protection device for a wind turbine top-mounted step-up transformer, which is combined with Figure 1 and Figure 2 The utility model is described with reference to the structural schematic diagram of FIG.

[0023] The following is combined with Figure 1 With attached Figure 2 , the specific implementation methods of the utility model are described in detail. In the description of the utility model, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the utility model.

[0024] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present utility model, unless otherwise specified, "plurality" means two or more.

[0025] It should be noted that the circuit connections involved in the present invention all adopt conventional circuit connection methods and do not involve any innovation.

[0026] Example: Please refer to Figure 1 and Figure 2 In an embodiment of the utility model, a distributed optical fiber differential protection device for a wind turbine top-mounted booster transformer is provided, comprising a low-voltage circuit breaker, a booster transformer and a high-voltage circuit breaker electrically connected in sequence; the low-voltage circuit breaker is electrically connected to the generator, and the high-voltage circuit breaker is electrically connected to the collector line; and further comprising:

[0027] a low voltage current transformer, the primary end of which is electrically connected between the low voltage circuit breaker and the step-up transformer;

[0028] An extension unit, electrically connected to the secondary end of the low-voltage current transformer, used to obtain the secondary protection current of the low-voltage side of the transformer and realize the conversion between the electrical signal and the optical signal. The extension unit is electrically connected to the low-voltage circuit breaker, used to control the low-voltage circuit breaker to break;

[0029] a high-voltage current transformer, a primary end of which is electrically connected between the step-up transformer and the high-voltage circuit breaker;

[0030] An optical fiber, one end of which is connected to the extension unit and is used for bidirectionally transmitting optical signals;

[0031] The main control unit is electrically connected to the secondary end of the high-voltage current transformer to obtain the secondary current on the high-voltage side of the transformer; the main control unit is connected to the other end of the optical fiber to achieve conversion between electrical signals and optical signals; the main control unit is electrically connected to the high-voltage circuit breaker to control the high-voltage circuit breaker to break.

[0032] Specifically, in the expansion unit, the acquired low-voltage side secondary protection current is converted into an optical signal through an electro-optical converter. The converted optical signal is coupled into the optical fiber through a lens. The optical signal carrying information is transmitted at a very high speed in the optical fiber until it reaches the main control unit.

[0033] In the main control unit, the optical signal is obtained through a photodetector, and the optical signal on the low-voltage side is converted into an electrical signal, thereby realizing the comparison of the protection currents on both sides of the transformer.

[0034] It needs to be explained that the extension unit collects the secondary current on the low-voltage side, converts the secondary current into an optical signal and transmits it to the main control unit through optical fiber, and converts the optical signal into an electrical signal in the main control unit. At the same time, the main control unit can collect the secondary current on the high-voltage side, thereby realizing comparison of the secondary currents on both sides of the transformer.

[0035] When the differential protection is in action, the communication unit receives the secondary protection current on the low-voltage side of the transformer sent by the extension unit, and sends the secondary protection current value to the main control unit;

[0036] When the differential protection is activated, the main control unit can trip the tower bottom circuit breaker and send a tripping command to the extension unit through the communication unit to make the extension unit trip the nacelle circuit breaker.

[0037] Therefore, in summary, the main control unit can collect the secondary protection current on both sides of the transformer, and can realize the numerical comparison of the protection current on both sides of the transformer. Specifically, when the difference between the secondary protection currents on both sides of the transformer is less than the set rated value, it means that the transformer is currently in a normal state and the differential protection does not move; when the difference between the secondary protection currents on both sides of the transformer is greater than the set rated value, it means that the transformer has an internal fault, and the differential protection is started to disconnect the two sides of the faulty transformer, thereby quickly removing the faulty transformer from the power system and ensuring the equipment safety of the wind turbine.

[0038] As a preferred embodiment, the low voltage circuit breaker and the low voltage current transformer are arranged in the cabin, and the high voltage current transformer and the high voltage circuit breaker are arranged in the bottom of the tower.

[0039] Specifically, the advantages of optical fiber over electrical cables are as follows: optical fiber transmits a large amount of data, while electrical cables usually transmit data in a single group, while optical fiber has a wider bandwidth and can accommodate more signals while transmitting a larger amount of data; the transmission speed of electrical cables is usually in the range of hundreds of megabits per second, while the transmission speed of optical fiber can reach several gigabits per second; during data transmission by electrical cables, it will be affected by the surrounding electromagnetic radiation and noise, which will interfere with data transmission, reduce transmission speed and signal quality, while optical fiber transmission will not be affected by electromagnetic interference, making optical fiber transmission signals more stable; the transmission distance of electrical cables is limited, usually only hundreds of meters, while the transmission distance of optical fibers can reach thousands of meters, the loss of optical signals is smaller than that of electrical signals, and the signal transmission distance is farther; electrical cables generate obvious heat when running for a long time and when multiple cables are stacked, while the heating of optical fibers only occurs when energy is lost and is basically not affected by the number of cables.

[0040] As a preferred embodiment, the high-voltage current transformer and the main control unit, as well as the low-voltage current transformer and the expansion unit are connected via conductors and cables; the main control unit and the high-voltage circuit breaker, as well as the expansion unit and the low-voltage circuit breaker are connected via switch control cables.

[0041] That is to say, through the feedback and negative feedback between the main control unit and the expansion unit, both sides of the step-up transformer are disconnected or not disconnected.

[0042] As a preferred embodiment, it also includes an auxiliary winding, which is connected to the conductor and cable between the low-voltage current transformer and the high-voltage current transformer, wherein the auxiliary winding can provide electrical energy for the wind turbine's own power system, thereby ensuring the normal operation of various systems and components of the wind turbine.

[0043] As a preferred embodiment, the protection winding and the measuring winding in the low-voltage current transformer and the high-voltage current transformer are both input in the form of alternating current, which has the characteristic of periodic change and can better reflect the real-time status of the power system.

[0044] Among them, the isolating grounding switch connected between the high-voltage current transformer and the high-voltage circuit breaker has the function of releasing the residual charge by grounding the system and equipment after the step-up transformer and the auxiliary winding are disconnected, which can greatly reduce the probability of electrical accidents.

[0045] As a preferred embodiment, it also includes a monitoring background, which is electrically connected to the main control unit to facilitate the visualization of the data collected by the main control unit.

[0046] As a preferred embodiment, a plug-in lightning arrester is connected between the high-voltage circuit breaker and the collector line. That is to say, when the power system is subjected to high transient overvoltage caused by lightning or other reasons, the lightning arrester can respond quickly and guide the overvoltage to the ground wire, thereby protecting the electrical equipment from damage.

[0047] As a preferred embodiment, a live display is connected between the high-voltage current transformer and the isolating grounding switch, and a live display is also connected between the high-voltage circuit breaker and the collector line, so that the staff can visually observe the operation of the power equipment.

[0048] In addition, from the development of wind power generation technology in the new energy industry, it can be foreseen that the application of top-mounted step-up transformers will become more and more extensive. This solution completely solves the problem that top-mounted step-up transformers can only be equipped with temperature protection, and fills the technical gap of the lack of differential protection for top-mounted step-up transformers. By setting up a distributed optical fiber differential protection device, the full-range current differential quick-break protection of the top-mounted step-up transformer is achieved, which greatly improves the safety and reliability of wind turbine operation and significantly improves the operation and maintenance level of wind turbines.

[0049] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A distributed optical fiber differential protection device for a wind turbine top-mounted booster transformer, comprising a low-voltage circuit breaker, a booster transformer and a high-voltage circuit breaker electrically connected in sequence; the low-voltage circuit breaker is electrically connected to the generator, and the high-voltage circuit breaker is electrically connected to the collector line; characterized in that: Also includes: a low voltage current transformer, the primary end of which is electrically connected between the low voltage circuit breaker and the step-up transformer; An extension unit is electrically connected to the secondary end of the low-voltage current transformer, and is used to obtain the secondary protection current of the low-voltage side of the transformer and realize the conversion between the electrical signal and the optical signal; the extension unit is electrically connected to the low-voltage circuit breaker, and is used to control the low-voltage circuit breaker to break; a high-voltage current transformer, a primary end of which is electrically connected between the step-up transformer and the high-voltage circuit breaker; An optical fiber, one end of which is connected to the extension unit and is used for bidirectionally transmitting optical signals; A main control unit is electrically connected to the secondary end of the high-voltage current transformer to obtain the secondary current on the high-voltage side of the transformer; the main control unit is connected to the other end of the optical fiber to achieve conversion between electrical signals and optical signals; the main control unit is electrically connected to the high-voltage circuit breaker to control the high-voltage circuit breaker to break; The low-voltage circuit breaker and the low-voltage current transformer are arranged in the cabin, and the high-voltage current transformer and the high-voltage circuit breaker are arranged in the bottom of the tower.

2. The distributed optical fiber differential protection device for the wind turbine top-mounted step-up transformer according to claim 1 is characterized in that: The high-voltage current transformer and the main control unit, as well as the low-voltage current transformer and the extension unit are connected via conductors and cables; the main control unit and the high-voltage circuit breaker, as well as the extension unit and the low-voltage circuit breaker are connected via switch control cables.

3. The distributed optical fiber differential protection device for the wind turbine top-mounted step-up transformer according to claim 2 is characterized in that: It also includes an auxiliary winding connected to the conductor and cable between the low-voltage current transformer and the high-voltage current transformer.

4. The distributed optical fiber differential protection device for the wind turbine top-mounted step-up transformer according to claim 3 is characterized in that: The protection winding and the measuring winding in the low-voltage current transformer and the high-voltage current transformer are both input in the form of alternating current.

5. The distributed optical fiber differential protection device for the wind turbine top-mounted step-up transformer according to claim 1 is characterized in that: It also includes a monitoring background, which is electrically connected to the main control unit.

6. The distributed optical fiber differential protection device for the wind turbine top-mounted step-up transformer according to claim 5 is characterized in that: A plug-in lightning arrester is connected between the high-voltage circuit breaker and the collector line.

7. The distributed optical fiber differential protection device for the wind turbine top-mounted step-up transformer according to claim 1 is characterized in that: A live display is connected between the high-voltage current transformer and the isolating grounding switch, and a display is also connected between the high-voltage circuit breaker and the collector line.

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