Frequency converter lightning stroke protection device

Abstract

The invention relates to the technical field of oil extraction equipment, in particular to a frequency converter lightning stroke protection device which comprises a primary fusing protector installed between a control transformer and a switching power supply of a frequency converter and used for controlling and cutting off a line between the switching power supply and the control transformer when real-time current in the line exceeds a first preset value; the secondary lightning protection device is connected in parallel between the primary fusing protection device and the switching power supply and is used for guiding part of current exceeding a second preset value into the ground when the real-time current value in the line caused by lightning stroke exceeds the second preset value; the signal isolator is installed between the frequency converter mainboard and the pressure switch and used for preventing lightning induction current on one side of the pressure switch from reversely flowing into the frequency converter while enabling a signal line of the frequency converter to enter the pressure switch. The invention discloses a lightning protection device, and aims to solve the problem that a circuit board and electronic components are damaged due to the fact that inductive charges are generated on metal fittings of electrical equipment and enter the interior of the equipment in a lightning induction mode when lightning occurs.

Description

Technical Field

[0001] The invention relates to the technical field of oil production equipment, and in particular to a frequency converter lightning protection device. Background Art

[0002] Lightning is a natural phenomenon. When lightning discharges, it can generate an impulse voltage of tens of thousands or even hundreds of thousands of volts, which is enough to burn electrical equipment such as generators, transformers, circuit breakers, etc. in the power system or break down the insulation of power transmission lines and cause a short circuit, leading to fire and explosion of flammable, inflammable and explosive items.

[0003] Existing technical measures for lightning protection include external lightning protection, that is, protection against direct lightning strikes, which leads lightning into the underground through lightning rods, etc. This measure can directly introduce most of the lightning energy into the earth; internal lightning protection, which is mainly composed of shielding, equipotential, overvoltage protection and safe distance, and its function is to balance the system potential and limit the overvoltage amplitude.

[0004] Although existing technologies can prevent lightning strikes from directly entering electrical equipment, when lightning occurs, strong induced charges will be generated on metal accessories and enter the interior of the equipment in the form of lightning induction, causing damage to circuit boards and electronic components.

[0005] Therefore, it is necessary to prevent lightning strikes while preventing overvoltage and high current induced by lightning from entering the inverter to avoid damage to the inverter caused by induced lightning. Summary of the invention

[0006] The present invention proposes a frequency converter lightning protection device to solve the problem that when lightning occurs, induced charges are generated on metal accessories of electrical equipment and enter the interior of the equipment in the form of lightning induction, causing damage to circuit boards and electronic components.

[0007] According to one aspect of the present invention, there is provided a frequency converter lightning protection device, comprising: a primary fuse protector, a secondary lightning protector and a signal isolator; The primary fuse protector is installed between the control transformer and the switching power supply of the inverter, and the primary fuse protector is used to control the cutting off of the line between the switching power supply and the control transformer when the real-time current value in the line exceeds a first predetermined value; The secondary lightning protection device is connected in parallel between the primary fuse protection device and the switch power supply, and the secondary lightning protection device is used to conduct the current exceeding the second predetermined value to the ground when the real-time current value in the line caused by lightning exceeds the second predetermined value; The signal isolator is installed between the frequency converter and the pressure switch. The signal isolator is used to prevent the current on one side of the pressure switch from flowing back into the frequency converter while allowing the frequency converter current to enter the pressure switch.

[0008] Preferably, the primary fuse protector is: a fuse switch; The output end of the control transformer is connected to the input end of the fuse switch through a line, and the output end of the fuse switch is respectively connected to the secondary lightning protection device and the switching power supply.

[0009] Preferably, the secondary lightning protection device is: a surge protector; The input end of the surge protector is connected to the primary fuse protector and the switching power supply respectively, and a grounding wire is led out from the grounding point of the surge protector to be grounded.

[0010] Preferably, the signal isolator is: an optocoupler relay; The signal input end of the frequency converter is connected to the output end of the optical coupler relay, and the input end of the optical coupler relay is connected to the signal output end of the pressure switch.

[0011] Preferably, it also includes: a low voltage power supply module; The input end of the surge protector is connected to the input end of the low-voltage power supply module through a line, and the output end of the low-voltage power supply module is respectively connected to the pressure switch and the signal isolator; The low-voltage power supply module is used to reduce the voltage output after passing through the surge protector to the voltage required by the pressure switch and the signal isolator, and then transmit it to the pressure switch and the signal isolator for power supply.

[0012] Preferably, the low voltage power supply module comprises: a first transformer, a rectifier bridge and a voltage stabilizing module; The input end of the first transformer is connected to the surge protector, the output end of the first transformer is connected to the input end of the rectifier bridge, the output end of the rectifier bridge is connected to the input end of the voltage regulator module, and the output end of the voltage regulator module is connected to the pressure switch and the signal isolator respectively.

[0013] Preferably, it also includes: a waterproof sealing box; The primary fuse protector, the secondary lightning protector and the signal isolator are installed in the waterproof sealing box.

[0014] The present invention has at least the following beneficial effects: The present invention proposes a frequency converter lightning protection device, which realizes dual protection of the frequency converter by setting a primary fuse protector and a secondary lightning protector, and prevents a large current at the electrical equipment end from entering the frequency converter through line reverse charging by setting a signal isolator; while preventing lightning strikes, it also prevents overvoltage and large current generated by lightning induction from entering the frequency converter, thereby avoiding damage to the frequency converter caused by induced lightning. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present invention and, together with the specification, are used to explain the technical solutions of the present invention.

[0016] Figure 1 A device connection diagram of a frequency converter lightning protection device according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of an optocoupler relay circuit according to an embodiment of the present invention is shown. Implementation

[0017] Various exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0018] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0019] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0020] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0021] Figure 1 A device connection diagram of a frequency converter lightning protection device according to an embodiment of the present invention is shown; Figure 2FIG. 2 shows a schematic diagram of an optocoupler relay circuit according to an embodiment of the present invention. Figure 1-2 As shown, a frequency converter lightning protection device includes: a primary fuse protector, a secondary lightning protector and a signal isolator; the primary fuse protector is installed between the control transformer and the switching power supply of the frequency converter, and the primary fuse protector is used to control the cutting off of the line between the switching power supply and the control transformer when the real-time current value in the line exceeds a first predetermined value; the secondary lightning protector is connected in parallel between the primary fuse protector and the switching power supply, and the secondary lightning protector is used to conduct the current exceeding the second predetermined value into the ground when the real-time current value in the line caused by lightning exceeds the second predetermined value; the signal isolator is installed between the frequency converter and the pressure switch, and the signal isolator is used to prevent the current on one side of the pressure switch from flowing back into the frequency converter while allowing the frequency converter current to enter the pressure switch.

[0022] In an embodiment of the present invention, during installation, the power supply line from the control transformer of the inverter to the switching power supply is removed and transferred to the input end of the first-level fuse protector. The output end of the first-level fuse protector is respectively connected to the input end of the second-level lightning protector and the switching power supply, and then the input end of the second-level lightning protector is connected back to the inverter switching power supply, thus forming double protection between the control transformer and the switching power supply.

[0023] When the large current generated by lightning strikes enters the primary fuse protector through the switching power supply, the primary fuse protector determines that if the current, that is, the real-time current value in the line is less than or equal to the first predetermined value, the current is transmitted through the line to the secondary lightning protector; if the secondary lightning protector determines that if the current, that is, the real-time current value in the line is greater than the second predetermined value, the current exceeding the second predetermined value is controlled to be introduced into the ground, and the current not exceeding the second predetermined value is transmitted to the electrical equipment through the switching power supply, the line and the pressure switch for power supply. When the large current generated by lightning strikes enters the primary fuse protector through the switching power supply, and the primary fuse protector determines that the real-time current value in the line is greater than the first predetermined value at this time, the line between the switching power supply and the control transformer is controlled to be cut off.

[0024] By installing two levels of insurance devices, a primary fuse protector and a secondary lightning protector, the overcurrent generated by lightning strikes can be blocked in time. The secondary lightning protector will conduct the instantaneous large current exceeding the second preset value into the ground to prevent the inverter from being impacted by large currents, so that the current value of the system power supply remains stable; the primary fuse protector can cut off the line between the switching power supply and the primary fuse protector and the inverter when the large current exceeds the first preset value, preventing the inverter from being burned due to the entry of large current, thereby achieving the purpose of double insurance protection. Among them, the first preset value can be set to 100A, and the second preset value can be set to 200A.

[0025] The pressure switch is connected to the inverter mainboard through a signal isolator, and the pressure switch is connected to the electrical equipment. If a large current in the line enters the inverter through the electrical equipment and the line connecting the pressure switch and the inverter, it may cause damage to the inverter. By setting up a signal isolator, the current reversed by the pressure switch enters the signal isolator first, and the signal isolator isolates the current flowing in from the pressure switch side to prevent it from entering the inverter. By installing a signal isolator at the inverter and the pressure switch, the signal transmission between the two is ensured, and the device isolation between the two is achieved, preventing large current from entering the inverter through the signal line between the inverter and the pressure switch, causing damage to the inverter.

[0026] In the present invention, the primary fuse protector is a fuse switch; the output end of the control transformer is connected to the input end of the fuse switch through a line, and the output end of the fuse switch is respectively connected to the secondary lightning protector and the switching power supply.

[0027] In the embodiment of the present invention, the output end of the control transformer is connected to the input end of the fuse switch, and the output end of the fuse switch is respectively connected to the input end of the secondary lightning arrester and the switch power supply. When the large current generated by lightning strikes enters the fuse switch through the switch power supply, if the current value exceeds the first predetermined value at this time, the fuse switch will quickly fuse and cut off the line to prevent the current from entering the secondary lightning arrester and the switch power supply, thereby preventing the switch power supply from being burned. Among them, the first predetermined value is: 200A.

[0028] In the present invention, the secondary lightning protection device is a surge protector; the input end of the surge protector is respectively connected to the primary fuse protector and the switching power supply, and the grounding point of the surge protector is connected to a grounding wire.

[0029] In the embodiment of the present invention, the output end of the primary fuse protector, i.e., the fuse switch, is connected to the input end of the surge protector, and the surge protector is connected to the grounding device through a lead wire, and the grounding device is buried underground. When a large current generated by a lightning strike enters the surge protector through the control transformer and the primary fuse protector, the surge protector transmits part of the current exceeding the second predetermined value to the grounding device through the lead wire, and the current is introduced into the ground through the grounding device, thereby ensuring the safe operation of the control transformer of the inverter.

[0030] In the present invention, the signal isolator is: an optocoupler relay; the signal input end of the frequency converter is connected to the output end of the optocoupler relay, and the input end of the optocoupler relay is connected to the signal output end of the pressure switch.

[0031] In an embodiment of the present invention, the input end of the pressure switch is connected to an electrical device. When a lightning strike occurs, if the electrical device is affected by the lightning strike, a large current may be generated, which is fed back to the inverter through the line and the pressure switch, causing damage to the inverter. Therefore, an optocoupler relay is installed between the inverter mainboard and the pressure switch. When the lightning induced current on one side of the pressure switch flows back into the inverter, the induced current is isolated on the line between it and the pressure switch through the optocoupler relay to prevent it from entering the inverter. Among them, the isolation voltage of the optocoupler relay is 100-1000V.

[0032] The present invention also includes: a low-voltage power supply module; the input end of the surge protector is connected to the input end of the low-voltage power supply module through a line, and the output end of the low-voltage power supply module is respectively connected to the pressure switch and the signal isolator; the low-voltage power supply module is used to reduce the voltage output after passing through the surge protector to the voltage required by the pressure switch and the signal isolator, and then transmit it to the pressure switch and the signal isolator for power supply.

[0033] In the embodiment of the present invention, the pressure switch and the optocoupler relay are powered separately by the low-voltage power supply module. When a large current enters, the optocoupler relay and the low-voltage power supply module will be burned out. The damage of the optocoupler relay protects the inverter mainboard, and the damage of the low-voltage power supply module protects the switching power supply of the inverter. Therefore, by leading the power supply line of the pressure switch and the optocoupler relay from the surge protector, the pressure switch and the optocoupler relay are powered by the low-voltage power supply module for voltage stabilization and adjustment to the available voltage of the pressure switch and the optocoupler relay, so as to ensure their normal operation and protect the inverter.

[0034] In the present invention, the low-voltage power supply module includes: a first transformer, a rectifier bridge and a voltage stabilizing module; the input end of the first transformer is connected to the surge protector, the output end of the first transformer is connected to the input end of the rectifier bridge, the output end of the rectifier bridge is connected to the input end of the voltage stabilizing module, and the output end of the voltage stabilizing module is connected to the pressure switch and the signal isolator respectively.

[0035] In the embodiment of the present invention, the power supply voltage required for the pressure switch and the signal isolator is 24VDC. A cable is led out from the 220V side of the surge protector, connected to the inverter switching power supply and the first transformer, the rectifier bridge, and the voltage stabilizing module in sequence; the 220V AC output by the surge protector enters the first transformer to be stepped down to 24V and then transmitted to the rectifier bridge, which converts the AC into DC and then transmits it to the voltage stabilizing module, which converts the unstable voltage output by the rectifier bridge into a stable adjustable voltage and then transmits it to the pressure switch and the signal isolator for power supply.

[0036] The present invention further comprises: a waterproof sealing box; the primary fuse protector, the secondary lightning protector and the signal isolator are installed in the waterproof sealing box.

[0037] In an embodiment of the present invention, the surge protector, the fuse switch, the optocoupler relay and the independent power supply that cooperates with it are all integrated in a waterproof sealing box, so that each component is protected to a certain extent and can effectively prevent water, moisture, dust and physical impact; at the same time, each lead interface is marked on the waterproof sealing box to meet the convenience of on-site installation.

[0038] Figure 2 FIG. 2 shows a schematic diagram of an optocoupler relay circuit according to an embodiment of the present invention. Figure 2 In the circuit, the 24V DC power output by the low voltage power supply module is connected to the DC+ and DC- terminals to power the optocoupler relay. The optocoupler relay uses a low level trigger. Connect the jumper between G and L, and the signal line to the DC- and IN terminals. When the signal is connected, the current passes from IN through the positive side of the bidirectional optocoupler through the 10K resistor, point L, point G, 10K resistor, and light-emitting diode to DC-. After the LTV-354T bidirectional optocoupler is lit, it triggers the K1 relay, causing the contacts of the K1 relay to close or open.

[0039] The present invention installs a surge protector at the control transformer and the switch power supply to divert the large current caused by lightning strike into the ground; at the same time, a fuse switch is installed at the installation position of the surge protector, and when a large current occurs, the fuse is sacrificed to protect the control transformer line; by installing an optical coupler relay at the frequency converter and the pressure switch, the signal transmission between the two is ensured, and the device isolation between the two is achieved, so as to prevent the large current from entering the frequency converter through the signal line between the frequency converter and the pressure switch, thereby causing damage to the frequency converter; a cable is led out on the 220V side of the surge protector, and a stable 24VDC voltage is obtained through a transformer, a rectifier bridge, and a voltage stabilizing module to power the pressure switch and the optical coupler isolation relay, so that the frequency converter switch power supply is isolated from the pressure switch, thereby preventing the surge current from entering the frequency converter, thereby causing damage to the frequency converter.

[0040] It can be understood that the above-mentioned various embodiments mentioned in the present invention can be combined with each other to form a combined embodiment without violating the principle logic. Due to space limitations, the present invention will not go into details.

[0041] The present invention removes the power supply line from the control transformer of the inverter to the switching power supply, transfers it to the power input end of the ESP inverter lightning protection device, and then connects it back to the inverter switching power supply from the position with the switching power supply mark, so as to form a double protection between the control transformer and the switching power supply. Through the added surge protector and the switch with the insurance device, the overcurrent is blocked when passing through the insurance, and the instantaneous large current is diverted into the ground, so as to achieve the protection of double insurance. The designed independent 24V DC voltage-regulated adjustable power supply (low voltage power supply module) can supply power to the active pressure switch and other equipment separately, replaces the switching power supply of the inverter itself, avoids the direct transmission of the cable of the external device to the inverter, and reduces the external factors that cause the inverter damage. The optocoupler relay isolation circuit is used at the signal input port of the inverter mainboard to isolate the signal of the external signal cable to the connection port of the mainboard, and the isolation method is used to prevent the inverter mainboard from being damaged by induced lightning.

[0042] The present invention provides multiple protections for the inverter lightning induction from multiple aspects, with excellent protection effects, and can effectively improve the lightning protection performance of the equipment. The present invention has been tested and applied in projects in Sudan, Chad and other overseas markets, with hundreds of inverters supporting submersible electric pump wells protected in the test, and the protection performance has reached 100%. Since its application, no equipment has been damaged by lightning, and very good test results have been achieved.

[0043] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A frequency converter lightning protection device, characterized in that: include: Primary fuse protector, secondary lightning protector and signal isolator; The primary fuse protector is installed between the control transformer and the switching power supply of the inverter, and the primary fuse protector is used to control the cutting off of the line between the switching power supply and the control transformer when the real-time current value in the line exceeds a first predetermined value; The secondary lightning protection device is connected in parallel between the primary fuse protection device and the switch power supply, and the secondary lightning protection device is used to conduct the current exceeding the second predetermined value to the ground when the real-time current value in the line caused by lightning exceeds the second predetermined value; The signal isolator is installed between the frequency converter and the pressure switch. The signal isolator is used to prevent the current on one side of the pressure switch from flowing back into the frequency converter while allowing the frequency converter current to enter the pressure switch.

2. The inverter lightning protection device according to claim 1, characterized in that: The primary fuse protector is: a fuse switch; The output end of the control transformer is connected to the input end of the fuse switch through a line, and the output end of the fuse switch is respectively connected to the secondary lightning protection device and the switching power supply.

3. The inverter lightning protection device according to claim 1, characterized in that: The secondary lightning protection device is: a surge protector; The input end of the surge protector is connected to the primary fuse protector and the switching power supply respectively, and a grounding wire is led out from the grounding point of the surge protector to be grounded.

4. The inverter lightning protection device according to claim 1, characterized in that: The signal isolator is: an optical coupler relay; The signal input end of the frequency converter is connected to the output end of the optical coupler relay, and the input end of the optical coupler relay is connected to the signal output end of the pressure switch.

5. The inverter lightning protection device according to claim 1, characterized in that: Also includes: Low voltage power supply module; The input end of the surge protector is connected to the input end of the low-voltage power supply module through a line, and the output end of the low-voltage power supply module is respectively connected to the pressure switch and the signal isolator; The low-voltage power supply module is used to reduce the voltage output after passing through the surge protector to the voltage required by the pressure switch and the signal isolator, and then transmit it to the pressure switch and the signal isolator for power supply.

6. The inverter lightning protection device according to claim 5, characterized in that: The low voltage power supply module includes: a first transformer, a rectifier bridge and a voltage stabilizing module; The input end of the first transformer is connected to the surge protector, the output end of the first transformer is connected to the input end of the rectifier bridge, the output end of the rectifier bridge is connected to the input end of the voltage regulator module, and the output end of the voltage regulator module is connected to the pressure switch and the signal isolator respectively.

7. The inverter lightning protection device according to any one of claims 1 to 6, characterized in that: Also includes: Waterproof sealed box; The primary fuse protector, the secondary lightning protector and the signal isolator are installed in the waterproof sealing box.

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