An anti-islanding protection device

Abstract

The application discloses a kind of anti-islanding protection devices, it is related to power grid security guarantee technical field, including protective shell and the anti-islanding equipment in protective shell, the anti-islanding equipment is electrically connected between distributed power generation system by normally open switch, ventilation machine is electrically connected with main power grid and is installed on the protective shell, the airflow output end of the ventilation machine is movably installed with extrusion unit, the ventilation machine can be kept on by extrusion unit in operating state normally open switch and apply support force to circuit conduction state, the anti-islanding equipment is electrically connected between distributed power generation system by normally open switch in the application, and ventilation machine is electrically connected with main power grid and is set, extrusion unit is arranged between ventilation machine and normally open switch, to realize the effect of double disconnection protection to distributed power generation system in cooperation with anti-islanding equipment, also play effective heat dissipation effect, improve the stability and security of anti-islanding equipment as a whole.

Description

Technical Field

[0001] This invention relates to the field of power grid security technology, specifically to an anti-islanding protection device. Background Technology

[0002] Anti-islanding protection devices in the power grid prevent the "islanding effect." The "islanding effect" refers to the situation where, when the main power grid loses power, distributed generation systems (such as photovoltaic or wind power) continue to supply power to surrounding loads, forming an isolated small power grid. This islanding effect can easily lead to problems such as affecting the safety of maintenance personnel, equipment damage, and grid restoration. The common solution is to add anti-islanding protection devices to the power grid to ensure the safety of personnel, equipment, and the power grid.

[0003] Anti-islanding protection devices quickly disconnect distributed generation systems from the grid when the grid is abnormal. Existing anti-islanding protection devices include Chinese Patent Publication No. CN118100291B, which is entitled "An anti-islanding protection device for grid-connected power generation in new energy power plants". This patent includes "connecting the switching assembly with the anti-islanding device, and automatically controlling the moving contact plate based on the rapid temperature change caused by the current surge due to the islanding effect, so that its top end separates from the fixed contact, thereby realizing dual anti-islanding disconnection protection for the power generation grid-connected transmission line, effectively avoiding the problem of power equipment damage caused by signal delay".

[0004] The above-mentioned solution adds a thermally expanding medium and uses the heat generated by the increased current to cause the thermally expanding medium to expand and deform, thereby generating a corresponding deformation force that disconnects the corresponding power grid line. However, this method has several drawbacks. First, the heat generated by the increased current is transferred to the thermally expanding medium before expansion is complete, resulting in a slow response time. Second, anti-islanding protection devices are usually located in a enclosure, where various circuit components easily generate heat during operation. The high temperature inside the enclosure can also easily cause the thermally expanding medium to suddenly expand, leading to a power grid line disconnection, resulting in poor stability. Furthermore, the method of generating heat by increasing the current can easily exacerbate the temperature increase inside the enclosure, increasing safety hazards in the power grid system and hindering its safety and stability. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-islanding protection device to overcome the shortcomings of the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An anti-islanding protection device includes a protective shell and an anti-islanding device located inside the protective shell. The anti-islanding device is electrically connected to a distributed generation system via a normally open switch. A fan electrically connected to the main power grid is installed on the protective shell. A compression unit is movably installed on the airflow output end of the fan. When the fan is in operation, it can apply a supporting force to the normally open switch through the compression unit to maintain the circuit conduction state.

[0008] Preferably, the extrusion unit includes a vertically downward-facing air duct, the ventilator is fixed inside the air duct, and an air-push structure is installed at the bottom of the air duct. The air-push structure can be pushed by the airflow generated by the ventilator to apply a supporting force to the normally open switch to maintain the circuit conduction state.

[0009] Preferably, the air-driven structure includes a manifold pipe fixedly extending through the bottom of the air duct, and a support column is adapted to be inserted into the manifold pipe. The manifold pipe can gather the airflow of the ventilator and push the support column toward the normally open switch.

[0010] Preferably, a dust filter cylinder is axially inserted into the inlet end of the air duct, a dust cleaning brush fixed to the air duct is provided on the outside of the dust filter cylinder, and an airtight valve is installed on the air duct, and the airtight valve is connected to the dust filter cylinder by a connecting rope.

[0011] Preferably, a bottom support plate is fixed to the bottom of the dust filter cylinder, and a plurality of support rods parallel to the support columns are fixed on the bottom support plate. When the dust filter cylinder is retracted into the air duct, the support rods apply a supporting force to the normally open switch to maintain the circuit conduction state.

[0012] Preferably, the airtight valve includes a valve body and a valve stem, one end of which extends vertically out of the outer side of the air duct, and the axial rotation of the valve stem can control the opening and closing state of the valve body.

[0013] Preferably, a top support plate is fixed on the support column, a gear is coaxially fixed on the valve stem body, a downward pressure rod parallel to the support column is fixed on the top support plate, and a rack capable of meshing with the gear is coaxially fixed at the bottom end of the downward pressure rod.

[0014] Preferably, the other end of the valve stem is located inside the air duct, and an arc hook is provided inside the air duct. One end of the arc hook is fixed to the valve stem via a connecting rod. When the airtight valve is in the venting state, the arc hook is hooked to the dust filter cylinder.

[0015] Preferably, the dust filter cylinder includes a sleeve, the side of which has an elongated opening, and a dust filter that contacts the dust cleaning brush is fixed inside the elongated opening. A ring is fixed at one end of the sleeve inserted into the air duct cylinder, and the ring can be adapted and hooked with the curved hook.

[0016] Preferably, the support column is a cylindrical column structure, and the support column is provided with multiple vent holes. Each vent hole can disperse the airflow in the air duct into the protective shell when the normally open switch circuit is in the conducting state.

[0017] In the above technical solution, the present invention provides an anti-islanding protection device, which electrically connects the anti-islanding equipment and the distributed generation system through a normally open switch, and sets up a ventilator electrically connected to the main grid. A compression unit is set between the ventilator and the normally open switch. When the ventilator is running, the compression unit applies a support force to the normally open switch to maintain the circuit conduction state. Therefore, when the main grid loses power, the ventilator stops running, thereby causing the normally open switch to switch to the circuit disconnected state. This works in conjunction with the anti-islanding equipment to achieve the effect of dual disconnection protection for the distributed generation system. The ventilator can also generate airflow changes inside and outside the protective shell, thereby also playing an effective role in heat dissipation, improving the overall stability and safety of the anti-islanding equipment. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is an internal schematic diagram of an anti-islanding protection device according to the present invention;

[0020] Figure 2 For the present invention Figure 1 Enlarged view of point A in the middle;

[0021] Figure 3 This is a schematic cross-sectional view of the airtight valve of an anti-islanding protection device according to the present invention;

[0022] Figure 4 This is a schematic diagram of a curved hook for an anti-islanding protection device according to the present invention;

[0023] Figure 5 This is a schematic diagram of the internal airflow path of an anti-islanding protection device according to the present invention;

[0024] Figure 6 This is a schematic diagram of the external protective shell of an anti-islanding protection device according to the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Protective shell; 1.1. Box shell; 1.2. Divider plate; 1.3. Opening; 1.4. Ventilation hole; 2. Anti-islanding device; 3. Normally open switch; 3.1. Protective box; 3.2. Conductive sheet; 3.3. Inlet; 3.4. Conductive plate; 4. Ventilator; 5. Extrusion unit; 5.1. Air duct; 5.2. Air-driven structure; 5.21. Manifold; 5.22. Support column; 5.23. Vent hole; 6. Dust filter cylinder 6.1 Sleeve; 6.2 Long slot; 6.3 Dust filter; 6.4 Ring; 7. Dust cleaning brush; 8. Airtight valve; 8.1 Valve body; 8.2 Valve stem; 8.3 Mandrel shaft; 8.4 Limiting slot; 8.5 Sliding block; 8.6 Winding roller; 9. Connecting rope; 10. Bottom support plate; 11. Support rod; 12. Top support plate; 13. Gear; 14. Down pressure rod; 15. Rack; 16. Arc hook; 17. Connecting rod. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] Please see Figures 1-6 An anti-islanding protection device provided in this embodiment of the invention includes a protective shell 1 and an anti-islanding device 2 located inside the protective shell 1. The anti-islanding device 2 is electrically connected to the distributed generation system through a normally open switch 3. A ventilator 4 electrically connected to the main power grid is installed on the protective shell 1. A compression unit 5 is movably installed on the airflow output end of the ventilator 4. When the ventilator 4 is in operation, it can apply a supporting force to the normally open switch 3 through the compression unit 5 to maintain the circuit conduction state.

[0029] Specifically, the protective shell 1 is a rectangular box, and the protective shell 1 has an air inlet corresponding to the airflow input end of the ventilator 4. The anti-islanding device 2 is an existing device composed of a microcomputer controller, inverter, voltage and current detection module, signal control module and transformer, etc., which will not be described in detail. The normally open switch 3 is a switch whose contacts are in the open state when not subjected to external pressure. The ventilator 4 can be a high-speed fan or blower, etc. The compression unit 5 can receive the airflow force of the ventilator 4, thereby applying compression force to the normally open switch 3, so that the normally open switch 3 is subjected to pressure and switches from the open state to the closed state, and keeps the normally open switch 3 in the closed state.

[0030] In actual use, the ventilator 4 receives power from the main grid, thus operating normally. This causes the normally open switch 3 in the distributed generation system to be closed, and the distributed generation system is in a closed state. When the power from the main grid is cut off, the ventilator 4 stops operating, the airflow disappears, and the normally open switch 3 returns to the open state. At this time, the distributed generation system is in a disconnected state, thus working in conjunction with the anti-islanding device 2 to achieve the effect of dual disconnection protection for the distributed generation system. The ventilator 4 can also generate airflow changes inside and outside the protective shell 1, thereby effectively cooling the anti-islanding device 2 inside the protective shell 1, improving the overall stability and safety of the anti-islanding device.

[0031] In another embodiment of the present invention, the protective shell 1 includes a housing 1.1, and a partition plate 1.2 is arranged horizontally inside the housing 1.1. The partition plate 1.2 divides the interior of the housing 1.1 into an upper space and a lower space. The bottom of the lower space has an opening 1.3 corresponding to the airflow input end of the ventilator 4. The side of the housing 1.1 has a plurality of ventilation holes 1.4 that communicate with the upper space. The ventilator 4 is fixedly installed through the partition plate 1.2.

[0032] In actual use, the ventilator 4 delivers air from the lower space to the upper space. The air in the upper space is dispersed outward through the vent 1.4, and the outside air is replenished into the lower space through the opening 1.3, thereby realizing the airflow inside the protective shell 1, which helps to remove the heat inside the protective shell 1 and achieve the effect of ventilation and cooling.

[0033] In another embodiment of the present invention, the extrusion unit 5 includes a vertically downward-facing air duct 5.1, the axis of which is perpendicular to the surface of the partition plate 1.2. The air duct 5.1 is fixedly inserted through the partition plate 1.2. The ventilator 4 is fixed inside the air duct 5.1. The opening of the air duct 5.1 is inverted and faces the open opening 1.3. The bottom end of the air duct 5.1 is located above the partition plate 1.2. An air-push structure 5.2 is installed at the bottom end of the air duct 5.1. The air-push structure 5.2 is located in the upper space and can be pushed by the airflow generated by the ventilator 4 to apply a supporting force to the normally open switch 3 to maintain the circuit conduction state.

[0034] Specifically, the air-driven structure 5.2 includes a manifold 5.21 fixedly penetrating the bottom of the duct 5.1. The top surface of the manifold 5.21 is flush with the top surface of the duct 5.1, and the axis of the manifold 5.21 coincides with the axis of the duct 5.1. The manifold 5.21 connects the bottom of the duct 5.1 to the outside. The pipe body of the manifold 5.21 is located inside the duct 5.1. A support column 5.22 is adapted and inserted into the manifold 5.21. The support column 5.22 can block the pipe of the manifold 5.21. The manifold 5.21 can gather the airflow of the fan 4 and push the support column 5.22 toward the normally open switch 3.

[0035] Specifically, the outlet of the ventilator 4 is connected to the manifold 5.21. The manifold 5.21 guides the airflow generated by the ventilator 4 to the outside of the duct 5.1. The support column 5.22 acts as a seal for the pipe of the manifold 5.21. The support column 5.22 is a cylindrical column structure. Multiple vent holes 5.23 are provided on the support column 5.22. Each vent hole 5.23 can disperse the airflow in the duct 5.1 into the protective shell 1 when the normally open switch 3 is in the conducting state.

[0036] In actual use, when the ventilator 4 is running, the airflow generated is transported to the outside of the duct 5.1 through the manifold 5.21. At this time, the support column 5.22 is pushed by the manifold 5.21 and moves axially, thus the support column 5.22 extends out of the manifold 5.21. The extended support column 5.22 compresses the normally open switch 3 located on the extension stroke of the support column 5.22, so that the normally open switch 3 is pressured to switch from the open state to the closed state. As the ventilator 4 continues to output airflow, the compressive force of the support column 5.22 on the normally open switch 3 is the support force to maintain the circuit conduction state.

[0037] At the same time, the vent 5.23 is also exposed outside the manifold 5.21 as the support column 5.22 extends, thereby dispersing the airflow in the duct 5.1 into the protective shell 1 and accelerating the airflow in the protective shell 1. When the fan 4 stops running, the support column 5.22 retracts into the manifold 5.21 under the action of gravity, and the normally open switch 3 also returns to the open state. Preferably, the support column 5.22 and the manifold 5.21 are connected by a spring, which can provide elastic assistance when the support column 5.22 retracts into the manifold 5.21.

[0038] In another embodiment of the present invention, a dust filter cylinder 6 is axially inserted into the opening end of the air duct 5.1. The opening of the dust filter cylinder 6 is inserted into the interior of the air duct 5.1. A dust cleaning brush 7 fixed to the air duct 5.1 is provided on the outside of the dust filter cylinder 6. An airtight valve 8 is installed on the air duct 5.1. The airtight valve 8 is connected to the dust filter cylinder 6 by a connecting rope 9.

[0039] Furthermore, a bottom support plate 10 is fixed to the bottom of the dust filter cylinder 6, and multiple support rods 11 parallel to the support column 5.22 are fixed on the bottom support plate 10. When the dust filter cylinder 6 is retracted into the air duct cylinder 5.1, the support rods 11 apply a supporting force to the normally open switch 3 to maintain the circuit conduction state.

[0040] The airtight valve 8 includes a valve body 8.1 and a valve stem 8.2. One end of the valve stem 8.2 extends vertically out of the outer side of the air duct 5.1. The airtight valve 8 is located between the dust filter cylinder 6 and the ventilator 4. The axial rotation of the valve stem 8.2 can control the opening and closing state of the valve body 8.1.

[0041] In addition, the other end of the valve stem 8.2 is located inside the air duct 5.1. The valve stem 8.2 has a tubular structure. The valve stem 8.2 is axially mounted with a core shaft 8.3. The air duct 5.1 is provided with an arc hook 16. One end of the arc hook 16 is fixed to the core shaft 8.3 via a connecting rod 17. A limiting slot 8.4 is provided on the valve stem 8.2. A slider 8.5 fixed to the core shaft 8.3 is slidably provided in the limiting slot 8.4. The slider 8.5 can slide relative to the limiting slot 8.4 along its length stroke. The two ends of the limiting slot 8.4 are the first end body and the second end body, respectively. A winding roller 8.6 connected to the connecting rope 9 is coaxially fixed to the end of the valve stem 8.2. When the airtight valve 8 is in the ventilated state, the arc hook 16 is hooked to the dust filter cylinder 6.

[0042] It should be further explained that a top support plate 12 is fixed on the support column 5.22, a gear 13 is coaxially fixed on the rod body of the mandrel shaft 8.3, a downward pressure rod 14 parallel to the support column 5.22 is fixed on the top support plate 12, a through hole is opened on the partition plate 1.2 for the downward pressure rod 14 to pass through, and a rubber insulating film sleeve covering the through hole is fixedly sleeved on the downward pressure rod 14 to maintain the separation and sealing of the partition plate 1.2 within the housing 1.1. A rack 15 that can mesh with the gear 13 is coaxially fixed at the bottom end of the downward pressure rod 14.

[0043] Furthermore, the dust filter cylinder 6 includes a sleeve 6.1, and the sleeve 6.1 has an elongated opening 6.2 on its side. A dust filter 6.3 that contacts the dust cleaning brush 7 is fixed inside the elongated opening 6.2. The dust filter 6.3 is a rigid mesh. One end of the sleeve 6.1 inserted into the air duct cylinder 5.1 is fixed with a ring 6.4. The ring 6.4 can be adapted to hook and connect with the curved hook 16.

[0044] In actual use, external air enters the lower space of the housing 1.1 through the opening 1.3, is filtered by the dust filter cylinder 6, and then enters the air duct 5.1. The dust and other floating objects filtered in the air are intercepted by the dust filter 6.3. As the usage time increases, the dust filter 6.3 becomes blocked by dust and other floating objects, which obstructs the entry of external air into the air duct 5.1. As the ventilator 4 continues to operate, the pressure in the space between the dust filter 6.3 and the ventilator 4 decreases. Under the action of atmospheric pressure, the dust filter cylinder 6 retracts into the air duct 5.1. During the retraction of the dust filter cylinder 6, the dust cleaning brush 7 moves relative to the dust filter cylinder 6. The dust cleaning brush 7 scrapes away the attached blockages on the dust filter 6.3, thus restoring the dust filter 6.3 to unobstructed flow.

[0045] It should be noted that as the ventilator 4 continues to operate, the dust filter 6.3 cleaned during the retraction and movement of the dust filter cylinder 6 will be covered and blocked again by dust, and the dust filter cylinder 6 will continue to retract and move. During the retraction and movement of the dust filter cylinder 6, the support rod 11 moves synchronously with the bottom support plate 10 fixed to the bottom of the dust filter cylinder 6.

[0046] When the dust filter cylinder 6 is retracted to the end of its stroke, the dust cleaning brush 7 and the dust filter cylinder 6 are in a relatively stationary state, and the support rod 11 also applies a supporting force to the normally open switch 3 to maintain the circuit conduction state.

[0047] When the dust filter 6.3 retracts to the end of its stroke and the dust filter cylinder 6 is covered and blocked, the dust filter cylinder 6 cannot retract further, and the fan 4 cannot continue to receive sufficient air to deliver into the manifold 5.21. Under the gravity of the support column 5.22, the top support plate 12, and the pressure rod 14, the support column 5.22 retracts into the manifold 5.21. Due to the negative pressure suction generated by the fan 4, the support rod 11 still applies a supporting force to the normally open switch 3 to maintain the circuit conduction state.

[0048] Since the ring 6.4 on the dust filter 6.3 at the end of its stroke is also located on the trajectory line of the curved hook 16, during the retraction of the support column 5.22, the support column 5.22 drives the pressure rod 14 to move downward through the top support plate 12. During the downward movement of the pressure rod 14, the pressure rod 14 engages with the gear 13 coaxially fixed on the rod body of the mandrel shaft 8.3 through the rack 15, thereby causing the mandrel shaft 8.3 to rotate in the forward direction, so that one end of the curved hook 16 passes through the ring 6 on the dust filter cylinder 6 via the connecting rod 17. 4. This causes the curved hook 16 to be hooked to the dust filter cylinder 6, keeping the dust filter cylinder 6 stationary at the end of its stroke and temporarily locking it at the end of its stroke. During this process, the slider 8.5 pushes the second end of the limiting slot 8.4, causing the valve stem 8.2 to rotate in the forward direction, thus switching the airtight valve 8 from the closed state to the open state. This allows external air to enter the airflow inlet of the ventilator 4 through the open airtight valve 8, and the ventilator 4 resumes air supply to the manifold 5.21.

[0049] It should be noted that during the forward drive engagement of the mandrel shaft 8.3, the curved hook 16 also continuously penetrates and deepens into the ring 6.4 as the mandrel shaft 8.3 rotates, thereby preventing the dust filter cylinder 6 from extending outward toward the air duct cylinder 5.1, and thus maintaining the support force exerted by the support rod 11 on the normally open switch 3 to keep the circuit conducting state unchanged;

[0050] In addition, during the forward rotation of the valve stem 8.2, the winding roller 8.6 winds the connecting rope 9 along with the forward rotation of the valve stem 8.2;

[0051] As the ventilation fan 4 resumes air supply to the manifold 5.21, the support column 5.22 extends out of the manifold 5.21 again. The extended support column 5.22 compresses the normally open switch 3 located on the extension stroke of the support column 5.22, providing support for the normally open switch 3 which is in the closed state. At this time, the normally open switch 3 is supported and compressed by the support rod 11 and the support column 5.22 and remains in the closed state. During the process of the support column 5.22 extending again, the support column 5.22 drives the pressure rod 14 to move upward through the top support plate 12. As the pressure rod 14 moves upward, it engages the gear 13 in the opposite direction. During this process, the slider 8.5 also moves from the second end of the limiting slot 8.4 toward the first end. The airtight valve 8 remains in the open state.

[0052] When slider 8.5 reaches the first end, one end of the curved hook 16 also detaches from the dust filter cylinder 6. At this time, the dust filter cylinder 6 is no longer pulled by the curved hook 16, and since the airtight valve 8 is still open, the spatial pressure between the dust filter 6.3 and the ventilator 4 is restored, and it is no longer squeezed by atmospheric pressure. Therefore, the dust filter cylinder 6 extends outward towards the duct 5.1 under the action of gravity. The entire extension movement process is the free fall process of the dust filter cylinder 6. During the extension movement of the dust filter cylinder 6, the relative movement between the dust cleaning brush 7 and the dust filter 6.3 causes the dust cleaning brush 7 to once again remove the attached blockages on the dust filter 6.3. During the scraping process, when the dust filter cylinder 6 extends to its final position, due to inertia, the valve stem 8.2 rotates in the reverse direction under the pull of the connecting rope 9, thus switching the airtight valve 8 from the open state to the closed state. At the same time, the slider 8.5 also returns from the first end position to the second end position, that is, the slider 8.5 returns to its initial position. Thus, the outside air enters the air duct 5.1 after being filtered by the dust filter cylinder 6. The dust and other floating objects filtered in the air are intercepted by the dust filter 6.3. When the dust filter 6.3 is blocked by dust and other floating objects, the dust filter cylinder 6 retracts into the air duct 5.1 to clean itself.

[0053] In another embodiment of the present invention, the normally open switch 3 includes a protective box 3.1, which is located above the pneumatic structure 5.2. The bottom surface of the protective box 3.1 is parallel to the horizontal plane. Both ends of the protective box 3.1 are fixed with conductive plates 3.2 connected to the distributed generation system lines. The conductive plates 3.2 are located at the top inner part of the protective box 3.1. Below the conductive plates 3.2, there is a conductive plate 3.4 located inside the protective box 3.1. When the conductive plate 3.4 is in contact with the two conductive plates 3.2 at the same time, the normally open switch 3 is in the closed state. When the conductive plate 3.4 is not in contact with the two conductive plates 3.2 at the same time, the normally open switch 3 is in the open state. The bottom of the protective box 3.1 is provided with an extension opening 3.3 for the support rod 11 and the support column 5.22 to pass through.

[0054] In actual use, the conductive plate 3.4 can accept the supporting force formed by the support rod 11 or the support column 5.22, thereby keeping the conductive plate 3.4 in contact with the two conductive pieces 3.2 at the same time, thus keeping the normally open switch 3 in the closed state. When the support rod 11 and the support column 5.22 are removed, the conductive plate 3.4 separates from the two conductive pieces 3.2 under the action of gravity. At this time, the normally open switch 3 is in the open state. Preferably, the conductive plate 3.4 is connected to the inner top of the protective box 3.1 by a spring, which helps the conductive plate 3.4 to remain separated from the conductive pieces 3.2 when the support rod 11 and the support column 5.22 are not present.

[0055] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. An anti-islanding protection device, comprising a protective housing (1) and an anti-islanding device (2) located within the protective housing (1), characterized in that, The anti-islanding device (2) is electrically connected to the distributed generation system via a normally open switch (3). A ventilator (4) electrically connected to the main power grid is installed on the protective shell (1). A squeezing unit (5) is movably installed on the airflow output end of the ventilator (4). When the ventilator (4) is in operation, it can apply a supporting force to the normally open switch (3) through the squeezing unit (5) to maintain the circuit conduction state. The extrusion unit (5) includes a vertically downward-facing air duct (5.1), the ventilator (4) is fixed inside the air duct (5.1), and an air-push structure (5.2) is installed at the bottom of the air duct (5.1). The air-push structure (5.2) can be pushed by the airflow generated by the ventilator (4) to apply a supporting force to the normally open switch (3) to maintain the circuit conduction state. The air-driven structure (5.2) includes a manifold (5.21) fixedly inserted through the bottom of the air duct (5.1). A support column (5.22) is adapted to be inserted into the manifold (5.21). The manifold (5.21) can gather the airflow of the fan (4) to push the support column (5.22) toward the normally open switch (3). A dust filter cylinder (6) is axially inserted into the opening end of the air duct (5.1). A dust cleaning brush (7) fixed to the air duct (5.1) is provided on the outside of the dust filter cylinder (6). An airtight valve (8) is installed on the air duct (5.1). The airtight valve (8) and the dust filter cylinder (6) are connected by a connecting rope (9). The bottom of the dust filter cylinder (6) is fixed with a base plate (10), and a plurality of support rods (11) parallel to the support column (5.22) are fixed on the base plate (10). When the dust filter cylinder (6) is retracted into the air duct cylinder (5.1), the support rods (11) apply a support force to the normally open switch (3) to maintain the circuit conduction state.

2. The anti-islanding protection device according to claim 1, characterized in that, The airtight valve (8) includes a valve body (8.1) and a valve stem (8.2). One end of the valve stem (8.2) extends vertically out of the outer side of the air duct (5.1). The axial rotation of the valve stem (8.2) can control the opening and closing state of the valve body (8.1).

3. The anti-islanding protection device according to claim 2, characterized in that, A top support plate (12) is fixed on the support column (5.22), a gear (13) is coaxially fixed on the valve stem (8.2), a downward pressure rod (14) parallel to the support column (5.22) is fixed on the top support plate (12), and a rack (15) capable of meshing with the gear (13) is coaxially fixed at the bottom end of the downward pressure rod (14).

4. The anti-islanding protection device according to claim 3, characterized in that, The other end of the valve stem (8.2) is located inside the air duct (5.1). The air duct (5.1) is provided with an arc hook (16). One end of the arc hook (16) is fixed to the valve stem (8.2) via a connecting rod (17). When the airtight valve (8) is in the ventilated state, the arc hook (16) is hooked to the dust filter cylinder (6).

5. The anti-islanding protection device according to claim 4, characterized in that, The dust filter cylinder (6) includes a sleeve (6.1), and a long opening (6.2) is provided on the side of the sleeve (6.1). A dust filter (6.3) that contacts the dust cleaning brush (7) is fixed inside the long opening (6.2). A ring (6.4) is fixed at one end of the sleeve (6.1) inserted into the air duct cylinder (5.1). The ring (6.4) can be adapted and hooked with the curved hook (16).

6. The anti-islanding protection device according to claim 5, characterized in that, The support column (5.22) is a cylindrical column structure. The support column (5.22) has multiple vent holes (5.23). Each vent hole (5.23) can disperse the airflow in the air duct (5.1) into the protective shell (1) when the normally open switch (3) circuit is in the conducting state.

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