Anti-islanding protection device

Abstract

The invention discloses an anti-islanding protection device, and relates to the technical field of power grid safety guarantee, the anti-islanding protection device comprises a protection shell and an anti-islanding device located in the protection shell, the anti-islanding device is electrically connected with a distributed power generation system through a normally open switch, and the protection shell is provided with a ventilator electrically connected with a main power grid. The anti-islanding equipment is electrically connected with the distributed power generation system through the normally-open switch, a squeezing unit is movably installed at the airflow output end of the ventilator, and the ventilator can apply supporting force for keeping the circuit in the on state to the normally-open switch through the squeezing unit in the running state. According to the anti-islanding device, the fan electrically connected with the main power grid is arranged, and the extrusion unit is arranged between the fan and the normally-open switch, so that the anti-islanding device cooperates with the anti-islanding device to achieve the effect of double-disconnection protection of the distributed power generation system, the effective heat dissipation effect is achieved, and the overall stability and safety of the anti-islanding device are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid security assurance, and particularly to an anti-islanding protection device. Background Art

[0002] The anti-islanding protection device plays a role in preventing the power grid from having an "islanding effect" in the power grid. The so-called "islanding effect" means that when the main power grid is powered off, the distributed generation system (such as photovoltaic or wind power) continues to supply power to the surrounding loads, forming an isolated small power grid, which is the islanding effect. Problems such as affecting the safety of maintenance personnel, equipment damage, and power grid restoration are likely to occur. The common treatment method is to add an anti-islanding protection device in the power grid to ensure the safety of personnel, equipment, and the power grid.

[0003] The anti-islanding protection device quickly disconnects the distributed generation system from the power grid when the power grid is abnormal. Existing anti-islanding protection devices such as the Chinese patent publication number: CN118100291B, the name of this patent is "An anti-islanding protection device for grid-connected power generation in a new energy power plant". This patent includes "by connecting the switch component to the anti-islanding device, automatically controlling the moving contact plate based on the rapid temperature change caused by the current surge in the islanding effect, so that its top separates from the fixed contact, realizing double 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 solution adds a heat-expandable thermal expansion medium, and uses the heat generated by the increased current to make the heated medium expand and deform, and then generates a corresponding deformation force to disconnect the corresponding power grid line. The disadvantages of the above method are that, on the one hand, there is a problem of slow response speed from the increase in current to the generation of heat, then the transfer of heat to the thermal expansion medium, and finally the completion of expansion; on the other hand, the anti-islanding protection device is usually concentrated in a box body, and various circuit devices are prone to generate heat during operation. The relatively high temperature in the box body is also likely to cause the thermal expansion medium to suddenly expand and form a disconnection of the power grid line, with poor stability; furthermore, the method of generating heat by increasing the current is also likely to exacerbate the increase in temperature in the box body, increasing the safety hazards in the power grid system and being unfavorable to the safety and stability of the power grid system. Summary of the Invention

[0005] The purpose of the present invention is to provide an anti-islanding protection device to solve the deficiencies in the above-mentioned prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[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 power generation system through a normally open switch. A ventilator electrically connected to the main power grid is installed on the protective shell. An extrusion unit is movably installed on the air output end of the ventilator. When the ventilator is in an operating state, it can apply a supporting force to keep the circuit in a conducting state to the normally open switch through the extrusion unit.

[0008] Preferably, the extrusion unit includes an air duct cylinder with its barrel opening vertically downward. The ventilator is fixed inside the air duct cylinder. An air-pushing structure is installed at the bottom end of the air duct cylinder. The air-pushing structure can be pushed by the airflow generated by the ventilator to apply a supporting force to keep the circuit in a conducting state to the normally open switch.

[0009] Preferably, the air-pushing structure includes a collecting pipe fixedly penetrating through the bottom of the air duct cylinder. A supporting column is adaptively inserted into the collecting pipe. The collecting pipe can gather the airflow of the ventilator to push the supporting column towards the normally open switch.

[0010] Preferably, a dust-filtering net cylinder is axially inserted into the barrel opening end of the air duct cylinder. A dust-cleaning brush fixed to the air duct cylinder is arranged outside the dust-filtering net cylinder. An airtight valve is installed on the air duct cylinder. The airtight valve is connected to the dust-filtering net cylinder through a connecting rope.

[0011] Preferably, a bottom support plate is fixed to the bottom of the dust-filtering net cylinder. A plurality of support rods parallel to the supporting column are fixed to the bottom support plate. When the dust-filtering net cylinder retracts into the air duct cylinder, the support rods apply a supporting force to keep the circuit in a conducting state to the normally open switch.

[0012] Preferably, the airtight valve includes a valve body and a valve rod. One end of the valve rod body vertically extends out of the outer side surface of the air duct cylinder. The axial rotation of the valve rod can control the opening and closing state of the valve body.

[0013] Preferably, a top support plate is fixed to the supporting column. A gear is coaxially fixed to the valve rod body. A pressing rod parallel to the supporting column is fixed to the top support plate. A rack capable of meshing and driving with the gear is coaxially fixed to the bottom end of the pressing rod.

[0014] Preferably, the other end of the valve rod body is located inside the air duct cylinder. An arc-shaped hook is arranged inside the air duct cylinder. One end of the arc-shaped hook is fixed to the valve rod body through a connecting rod. When the airtight valve is in a ventilation state, the arc-shaped hook is in a hooked state with the dust-filtering net cylinder.

[0015] Preferably, the dust-filtering net cylinder includes a sleeve. A long strip opening is formed on the side surface of the sleeve. A dust-filtering net in contact with the dust-cleaning brush is fixed in the long strip opening. A ring is fixed to one end of the sleeve inserted into the air duct cylinder. The ring can be adaptively hooked with the arc-shaped hook.

[0016] Preferably, the supporting column is a tubular column structure, and a plurality of air vent holes are formed in the supporting column. Each air vent hole can evacuate the air flow in the air duct cylinder to the protective shell when the normally open switch circuit is in a conducting state.

[0017] In the above technical solution, an anti-islanding protection device provided by the present invention is electrically connected between the anti-islanding device and the distributed power generation system through a normally open switch, and a ventilator electrically connected to the main power grid is provided. An extrusion unit is arranged between the ventilator and the normally open switch. When the ventilator is in an operating state, the extrusion unit applies a supporting force to keep the circuit in a conducting state to the normally open switch. Thus, when the main power grid is powered off, the ventilator stops operating, and further the normally open switch switches to a circuit-off state, so as to cooperate with the anti-islanding device to achieve the effect of double-disconnection protection for the distributed power generation system. The ventilator can also generate air flow changes inside and outside the protective shell, thus also achieving an effective heat dissipation effect, and improving the overall stability and safety of the anti-islanding device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0019] Figure 1 Internal schematic diagram of an anti-islanding protection device of the present invention;

[0020] Figure 2 For the present invention Figure 1 Enlarged view at A in;

[0021] Figure 3 Cross-sectional schematic diagram of an airtight valve of an anti-islanding protection device of the present invention;

[0022] Figure 4 Schematic diagram of a curved arc hook of an anti-islanding protection device of the present invention;

[0023] Figure 5 Schematic diagram of the internal air flow path of an anti-islanding protection device of the present invention;

[0024] Figure 6 External schematic diagram of the protective shell of an anti-islanding protection device of the present invention.

[0025] Description of the reference numerals:

[0026] 1. Protective shell; 1.1. Box housing; 1.2. Partition board; 1.3. Open port; 1.4. Air vent hole; 2. Anti-islanding device; 3. Normally open switch; 3.1. Protective box; 3.2. Conductive sheet; 3.3. Insertion port; 3.4. Conductive plate; 4. Ventilator; 5. Extrusion unit; 5.1. Air duct cylinder; 5.2. Air-pushing structure; 5.21. Manifold pipe; 5.22. Support pillar; 5.23. Air leakage hole; 6. Dust filter net cylinder; 6.1. Sleeve; 6.2. Long strip opening; 6.3. Dust filter net; 6.4. Ring; 7. Dust cleaning brush; 8. Airtight valve; 8.1. Valve body; 8.2. Valve rod; 8.3. Core rod shaft; 8.4. Limit notch; 8.5. Slide block; 8.6. Winding roller; 9. Connecting rope; 10. Bottom support plate; 11. Support rod; 12. Top support plate; 13. Gear; 14. Pressing rod; 15. Rack; 16. Curved hook; 17. Connecting rod. Detailed implementation manners

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

[0028] Please refer to Figures 1-6 , a kind of anti-islanding protection device provided by an embodiment of the present 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 a distributed power 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. An extrusion unit 5 is movably installed on the air flow output end of the ventilator 4. When the ventilator 4 is in an operating state, it can apply a supporting force to keep the circuit in a conducting state to the normally open switch 3 through the extrusion unit 5;

[0029] Specifically, the protective shell 1 is a rectangular box body. An air inlet corresponding to the air flow input end of the ventilator 4 is opened on the protective shell 1. The anti-islanding device 2 is an existing device composed of a microcomputer controller, an inverter, a voltage and current detection module, a signal control module, a transformer, etc., which will not be elaborated. The normally open switch 3 is a switch whose contacts are in an open state when not subjected to an external extrusion force. The ventilator 4 can be selected as a high-speed fan or a blower, etc. The extrusion unit 5 can receive the air flow blowing force of the ventilator 4, thereby applying an extrusion force to the normally open switch 3, so that the normally open switch 3 is switched from an open state to a closed state under pressure, and the normally open switch 3 is kept in a closed state;

[0030] During actual use, the fan 4 receives power supply from the main power grid, so that the fan 4 operates normally, and the normally open switch 3 in the distributed power generation system is in a closed state, and the distributed power generation system is in a pass state; when the power of the main power grid is cut off, the fan 4 stops running and the wind disappears, and the normally open switch 3 returns to the disconnected state. At this time, the distributed power generation system is in an open circuit state, and then cooperates with the anti-islanding device 2 to achieve the effect of double disconnection protection for the distributed power generation system. The fan 4 can also generate airflow changes inside and outside the protective shell 1, thereby effectively cooling the anti-islanding device 2 in the protective shell 1, thereby improving the overall stability and safety of the anti-islanding device.

[0031] In another embodiment provided by the present invention, the protective shell 1 includes a box shell 1.1, a partition plate 1.2 is arranged transversely in the box shell 1.1, and the partition plate 1.2 divides the inside of the box shell 1.1 into an upper space and a lower space, and an opening 1.3 corresponding to the airflow input end of the ventilator 4 is provided at the bottom of the lower space, and a plurality of air diffusion holes 1.4 connected to the upper space are provided on the side of the box shell 1.1, and the ventilator 4 is fixedly installed on the partition plate 1.2;

[0032] During actual use, the ventilator 4 transports the air in the lower space to the upper space, the air in the upper space is dispersed outward through the air diffusion holes 1.4, and the external air is replenished into the lower space through the open port 1.3, thereby realizing the air flow inside the protective shell 1, which is beneficial to take away the heat inside the protective shell 1 and achieve the effect of ventilation and cooling.

[0033] In another embodiment provided by the present invention, the extrusion unit 5 includes an air duct tube 5.1 with a tube opening vertically downward, the axis of the air duct tube 5.1 is perpendicular to the plate surface of the partition plate 1.2, the air duct tube 5.1 is fixed and penetrates the partition plate 1.2, the ventilator 4 is fixed in the air duct tube 5.1, the tube opening of the air duct tube 5.1 is inverted, the tube opening of the air duct tube 5.1 faces the open port 1.3, the tube bottom end of the air duct tube 5.1 is located above the partition plate 1.2, and an air push structure 5.2 is installed at the tube bottom end of the air duct tube 5.1, the air push structure 5.2 is located in the upper space, and the air push structure 5.2 can be pushed by the airflow generated by the ventilator 4 and exert a supporting force on the normally open switch 3 to keep the circuit in a conductive state;

[0034] Specifically, the air-pushing structure 5.2 includes a manifold 5.21 fixedly penetrating the bottom of the air duct cylinder 5.1. The top surface of the manifold 5.21 is flush with the top surface of the air duct cylinder 5.1, and the axis line of the manifold 5.21 coincides with the axis line of the air duct cylinder 5.1. The manifold 5.21 connects the bottom of the air duct cylinder 5.1 to the outside. The pipe body of the manifold 5.21 is located inside the air duct cylinder 5.1. A support column 5.22 is adaptively inserted into the manifold 5.21. The support column 5.22 can block the pipeline of the manifold 5.21. The manifold 5.21 can gather the air flow of the ventilator 4 and push the support column 5.22 towards the normally open switch 3;

[0035] Specifically, the air outlet end of the ventilator 4 is connected to the manifold 5.21 in a butt joint manner. The manifold 5.21 guides the air flow generated by the ventilator 4 to the outside of the air duct cylinder 5.1. The support column 5.22 blocks the pipeline of the manifold 5.21. Among them, the support column 5.22 is of a tube column structure, and a plurality of air leakage holes 5.23 are opened on the support column 5.22. Each air leakage hole 5.23 can evacuate the air flow in the air duct cylinder 5.1 into the protective shell 1 when the normally open switch 3 is in a conducting state;

[0036] During actual use, when the ventilator 4 is running, the generated air flow is transported to the outside of the air duct cylinder 5.1 through the manifold 5.21. At this time, the support column 5.22 moves axially under the extrusion of the manifold 5.21, so that the support column 5.22 extends out of the manifold 5.21. The extended support column 5.22 squeezes the normally open switch 3 located on the extending stroke of the support column 5.22, so that the normally open switch 3 is switched from the off state to the on state under the pressure. As the ventilator 4 continuously outputs air flow, the extrusion force of the support column 5.22 on the normally open switch 3 is the supporting force to maintain the conducting state of the circuit;

[0037] At the same time, the air leakage holes 5.23 are also exposed outside the manifold 5.21 as the support column 5.22 extends, so as to evacuate the air flow in the air duct cylinder 5.1 into the protective shell 1, accelerating the air flow in the protective shell 1. When the ventilator 4 stops running, at this time, 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 off state. Preferably, the support column 5.22 and the manifold 5.21 are connected by a spring, so as to provide elastic assistance when the support column 5.22 retracts into the manifold 5.21.

[0038] Another embodiment provided by the present invention is that a dust filter cylinder 6 is axially inserted into the mouth end of the air duct cylinder 5.1. The mouth of the dust filter cylinder 6 is inserted into the inside of the air duct cylinder 5.1. A dust cleaning brush 7 fixed to the air duct cylinder 5.1 is provided on the outside of the dust filter cylinder 6. An airtight valve 8 is installed on the air duct cylinder 5.1. The airtight valve 8 and the dust filter cylinder 6 are connected by a connecting rope 9;

[0039] Further, a bottom support plate 10 is fixed to the bottom of the dust filtering cylinder 6. A plurality of support rods 11 parallel to the support columns 5.22 are fixed to the bottom support plate 10. When the dust filtering cylinder 6 retracts into the air duct cylinder 5.1, the support rods 11 apply a supporting force to keep the normally open switch 3 in a conductive state;

[0040] Among them, the airtight valve 8 includes a valve body 8.1 and a valve stem 8.2. One end of the rod body of the valve stem 8.2 vertically extends out of the outer side of the air duct cylinder 5.1. The airtight valve 8 is located between the dust filtering 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 rod body of the valve stem 8.2 is located inside the air duct cylinder 5.1. The valve stem 8.2 is of a pipe column structure. A core rod shaft 8.3 is coaxially and rotatably installed on the axial direction of the rod body of the valve stem 8.2. An arc-shaped hook 16 is arranged inside the air duct cylinder 5.1. One end of the arc-shaped hook 16 is fixed to the rod body of the core rod shaft 8.3 through a connecting rod 17. A limiting notch 8.4 is formed on the rod body of the valve stem 8.2. A slider 8.5 fixed to the core rod shaft 8.3 is slidably arranged in the limiting notch 8.4. The slider 8.5 can slide relatively within the length stroke of the limiting notch 8.4. The two ends of the limiting notch 8.4 are respectively a first end body and a second end body. A winding roller 8.6 connected to the connecting rope 9 is coaxially fixed to the end of the rod body of the valve stem 8.2. When the airtight valve 8 is in a ventilation state, the arc-shaped hook 16 is in a hooked state with the dust filtering cylinder 6;

[0042] It should be further noted that a top support plate 12 is fixed to the support column 5.22. A gear 13 is coaxially fixed to the rod body of the core rod shaft 8.3. A pressing rod 14 parallel to the support column 5.22 is fixed to the top support plate 12. A through hole for the pressing rod 14 to penetrate is formed on the partition plate 1.2. A rubber isolation membrane sleeve covering the through hole is fixedly sleeved on the pressing rod 14 to maintain the partition sealing property of the partition plate 1.2 inside the box housing 1.1. A rack 15 capable of meshing with the gear 13 is coaxially fixed to the bottom end of the pressing rod 14;

[0043] Further, the dust filtering cylinder 6 includes a sleeve 6.1. A long strip opening 6.2 is formed on the side surface of the sleeve 6.1. A dust filtering net 6.3 in contact with the dust cleaning brush 7 is fixed in the long strip opening 6.2. The dust filtering net 6.3 is a hard net. A ring 6.4 is fixed to one end of the sleeve 6.1 inserted into the air duct cylinder 5.1. The ring 6.4 can be adaptively hooked with the arc-shaped hook 16.

[0044] During actual use, external air enters the lower space of the box housing 1.1 through the opening 1.3, passes through the dust filter cartridge 6, and then enters the air duct cylinder 5.1. Floating substances such as dust filtered from the air are intercepted by the dust filter screen 6.3. As the usage time increases, the dust filter screen 6.3 is covered by dust and other floating substances and becomes blocked, preventing external air from entering the air duct cylinder 5.1. As the ventilator 4 continues to operate, the pressure in the space between the dust filter screen 6.3 and the ventilator 4 decreases. Under the action of atmospheric pressure, the dust filter cartridge 6 moves inwardly towards the air duct cylinder 5.1. During the inward movement of the dust filter cartridge 6, relative movement occurs between the dust cleaning brush 7 and the dust filter cartridge 6, and the dust cleaning brush 7 scrapes off the attached blockages on the dust filter screen 6.3, thus restoring the dust filter screen 6.3 to a clear state;

[0045] It should be noted specifically that as the ventilator 4 continues to operate, during the inward movement of the dust filter cartridge 6, the dust filter screen 6.3 being cleaned will be covered and blocked by dust again, so the dust filter cartridge 6 continues to move inward. During the inward movement of the dust filter cartridge 6, the support rod 11 moves synchronously with the bottom support plate 10 fixed to the bottom of the dust filter cartridge 6;

[0046] When the inward movement of the dust filter cartridge 6 reaches the end of its stroke, at this time, the relative static state exists between the dust cleaning brush 7 and the dust filter cartridge 6, and the support rod 11 also applies a supporting force to keep the normally open switch 3 in a conducting state;

[0047] When the dust filter screen 6.3 moves inward to the end of its stroke and the dust filter cartridge 6 is covered and blocked, at this time, the dust filter cartridge 6 cannot move further inward, and the ventilator 4 cannot continue to obtain sufficient air to transport into the manifold 5.21. Under the gravitational action of components such as the support column 5.22, the top support plate 12, and the pressure rod 14, at this time, the support column 5.22 retracts into the manifold 5.21, and due to the negative pressure suction generated by the ventilator 4, the support rod 11 still applies a supporting force to keep the normally open switch 3 in a conducting state.

[0048] Since the loop 6.4 on the dust filter net 6.3 at the end of the stroke is also located on the movement track line of the arc-shaped hook 16, during the retraction process of the supporting column 5.22, the supporting column 5.22 drives the pressure rod 14 to move downward through the top plate 12. During the downward movement of the pressure rod 14, the pressure rod 14 is in positive transmission engagement with the gear 13 coaxially fixed on the rod body of the mandrel shaft 8.3 through the rack 15. Thus, the mandrel shaft 8.3 rotating in the positive direction makes one end of the arc-shaped hook 16 pass through the loop 6.4 on the dust filter net cylinder 6, so that the arc-shaped hook 16 is in a hooked state with the dust filter net cylinder 6, keeping the dust filter net cylinder 6 stationary at the end of the stroke and temporarily locking the dust filter net cylinder 6 at the end-of-stroke position; during this process, the slider 8.5 makes the valve rod 8.2 rotate in the positive axial direction by pushing the second end body of the limiting notch 8.4, so that the airtight valve 8 is switched from the closed state to the open state, and thus the external air can enter the air inlet end of the ventilator 4 through the open airtight valve 8, and the ventilator 4 resumes supplying air to the manifold 5.21;

[0049] It should be noted in particular that during the positive transmission engagement of the mandrel shaft 8.3, the arc-shaped hook 16 also continuously penetrates into the loop 6.4 as the mandrel shaft 8.3 rotates, thereby preventing the dust filter net cylinder 6 from moving outwards towards the air duct cylinder 5.1, and further keeping the supporting force of the supporting rod 11 on the normally open switch 3 to maintain the conducting state of the holding circuit unchanged;

[0050] In addition, during the positive axial rotation of the valve rod 8.2, the winding roller 8.6 winds the connecting rope 9 as the valve rod 8.2 rotates in the positive axial direction;

[0051] As the ventilator 4 resumes supplying air to the manifold 5.21, at this time, the supporting column 5.22 moves out of the manifold 5.21 again. The protruding supporting column 5.22 squeezes the normally open switch 3 located on the extending stroke of the top column 5.22, and also provides a supporting force for the normally open switch 3 in the closed state. At this time, the normally open switch 3 is supported and squeezed by the supporting rod 11 and the supporting column 5.22 and remains in the closed state; during the process of the supporting column 5.22 moving out again, the supporting column 5.22 drives the pressure rod 14 to move upward through the top plate 12. Thus, during the upward movement of the pressure rod 14, it is in reverse transmission engagement with the gear 13. During this process, the slider 8.5 also moves from the second end body of the limiting notch 8.4 towards the first end body, and the airtight valve 8 remains in the open state.

[0052] When the slider 8.5 reaches the first end body, at this time, one end of the arc-shaped hook 16 is also disengaged from the dust filter cartridge 6. At this time, the dust filter cartridge 6 is not pulled by the arc-shaped hook 16. At the same time, since the airtight valve 8 is still in the open state, the air pressure in the space between the dust filter 6.3 and the ventilator 4 is restored and is no longer squeezed by the atmospheric pressure. Therefore, the dust filter cartridge 6 moves outwards towards the outside of the air duct cylinder 5.1 under the action of gravity. The entire moving-out process is a free-fall process of the dust filter cartridge 6. During the moving-out process of the dust filter cartridge 6, the relative movement between the dust cleaning brush 7 and the dust filter 6.3 causes the dust cleaning brush 7 to scrape off the attached blockages on the dust filter 6.3 again. When the dust filter cartridge 6 moves out to the outermost end, due to inertia, the valve rod 8.2 rotates reversely under the pulling of the connecting rope 9, so that the airtight valve 8 is switched from the open state to the closed state. At the same time, the slider 8.5 also returns from the first end body position to the second end body position, that is, the slider 8.5 returns to the initial position. Thus, the external air enters the air duct cylinder 5.1 after being filtered by the dust filter cartridge 6, and the floating dust and other substances in the air are intercepted by the dust filter 6.3. When the dust filter 6.3 is blocked by the covering of dust and other floating substances, the dust filter cartridge 6 moves inwards towards the air duct cylinder 5.1 for self-cleaning.

[0053] Another embodiment provided by the present invention, the normally open switch 3 includes a protective box 3.1. The protective box 3.1 is located above the air-pushing structure 5.2. The bottom surface of the protective box 3.1 is parallel to the horizontal plane. Conductive sheets 3.2 connected to the distributed power generation system circuit are fixed at both ends of the protective box 3.1. The conductive sheets 3.2 are located at the inner top of the protective box 3.1. A conductive plate 3.4 is provided below the conductive sheets 3.2 inside the protective box 3.1. When the conductive plate 3.4 is in contact with the two conductive sheets 3.2 at the same time, the normally open switch 3 is in a conducting state. When the conductive plate 3.4 is not in contact with the two conductive sheets 3.2 at the same time, the normally open switch 3 is in an open state. An insertion opening 3.3 for the support rod 11 and the support column 5.22 to penetrate is opened at the bottom of the protective box 3.1;

[0054] During actual use, the conductive plate 3.4 can receive the supporting force formed by the support of the support rod 11 or the support column 5.22, so as to keep the conductive plate 3.4 in contact with the two conductive sheets 3.2 at the same time, so as to keep the normally open switch 3 in a conducting state. When both the support rod 11 and the support column 5.22 are withdrawn, at this time, under the action of gravity, the conductive plate 3.4 is separated from the two conductive sheets 3.2, and at this time, the normally open switch 3 is in an open state. Preferably, the conductive plate 3.4 is connected to the inner top of the protective box 3.1 by a spring, which is beneficial to keep the conductive plate 3.4 separated from the conductive sheet 3.2 when there is no support rod 11 and support column 5.22.

[0055] Only some exemplary embodiments of the present invention have been described by way of illustration. Without doubt, for those of ordinary skill in the art, the described embodiments can be modified in various different ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description 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 shell (1) and an anti-islanding device (2) located inside the protective shell (1), characterized in that, The anti-islanding device (2) is electrically connected to the distributed power 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). An extrusion unit (5) is movably installed at the air flow output end of the ventilator (4). When the ventilator (4) is in an operating state, the extrusion unit (5) can apply a supporting force to keep the circuit in a conducting state to the normally open switch (3).

2. The anti-islanding protection device according to claim 1, characterized in that, The extrusion unit (5) includes an air duct cylinder (5.1) with a vertically downward cylinder opening. The ventilator (4) is fixed inside the air duct cylinder (5.1). An air-pushing structure (5.2) is installed at the bottom end of the air duct cylinder (5.1). The air-pushing structure (5.2) can be pushed by the air flow generated by the ventilator (4) to apply a supporting force to keep the circuit in a conducting state to the normally open switch (3).

3. The anti-islanding protection device according to claim 2, characterized in that, The air-pushing structure (5.2) includes a collecting pipe (5.21) fixedly penetrating through the bottom of the air duct cylinder (5.1). A supporting column (5.22) is adaptively inserted into the collecting pipe (5.21). The collecting pipe (5.21) can gather the air flow of the ventilator (4) to push the supporting column (5.22) towards the normally open switch (3).

4. An anti-islanding protection device according to claim 2, characterized in that, A dust-filtering net cylinder (6) is axially inserted into the cylinder opening end of the air duct cylinder (5.1). A dust-cleaning brush (7) fixed to the air duct cylinder (5.1) is arranged outside the dust-filtering net cylinder (6). An airtight valve (8) is installed on the air duct cylinder (5.1). The airtight valve (8) is connected to the dust-filtering net cylinder (6) through a connecting rope (9).

5. The anti-islanding protection device according to claim 4, characterized in that, A bottom supporting plate (10) is fixed to the bottom of the dust-filtering net cylinder (6). A plurality of supporting rods (11) parallel to the supporting column (5.22) are fixed to the bottom supporting plate (10). When the dust-filtering net cylinder (6) retracts into the air duct cylinder (5.1), the supporting rods (11) apply a supporting force to keep the circuit in a conducting state to the normally open switch (3).

6. The anti-islanding protection device according to claim 5, characterized in that, The airtight valve (8) includes a valve body (8.1) and a valve rod (8.2). One end of the rod body of the valve rod (8.2) vertically extends out of the outer side surface of the air duct cylinder (5.1). The axial rotation of the valve rod (8.2) can control the opening and closing state of the valve body (8.1).

7. An anti-islanding protection device according to claim 6, characterized in that, A top supporting plate (12) is fixed to the supporting column (5.22). A gear (13) is coaxially fixed to the rod body of the valve rod (8.2). A pressing rod (14) parallel to the supporting column (5.22) is fixed to the top supporting plate (12). A rack (15) capable of meshing with the gear (13) is coaxially fixed to the bottom end of the pressing rod (14).

8. An anti-islanding protection device according to claim 7, characterized in that, The other end of the rod body of the valve rod (8.2) is located inside the air duct cylinder (5.1). An arc-shaped hook (16) is arranged inside the air duct cylinder (5.1). One end of the arc-shaped hook (16) is fixed to the rod body of the valve rod (8.2) through a connecting rod (17). When the airtight valve (8) is in a ventilation state, the arc-shaped hook (16) is in a hooked state with the dust-filtering net cylinder (6).

9. The anti-islanding protection device according to claim 8, characterized in that, The dust filter cartridge (6) includes a sleeve (6.1), a long strip opening (6.2) is formed on the side surface of the sleeve (6.1), a dust filter screen (6.3) in contact with the dust cleaning brush (7) is fixed in the long strip 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), and the ring (6.4) can be adaptively hooked with the arc-shaped hook (16).

10. The anti-islanding protection device according to claim 2, characterized in that, The supporting column (5.22) is of a tubular column structure, a plurality of air leakage holes (5.23) are formed on the supporting column (5.22), and each of the air leakage holes (5.23) can evacuate the air flow in the air duct cylinder (5.1) to the protective housing (1) when the circuit of the normally open switch (3) is turned on.

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