278results about How to "Protect safe operation" patented technology

The invention discloses an AC / DC fault ride-through and energy dissipation method for wind power flexible direct grid connection. A system is mainly formed by a direct-drive permanent magnet synchronous generator, a full-power frequency converter, a hybrid MMC and a dissipative resistor. An AC and DC are controlled respectively through the hybrid MMC; during direct current faults, the MMC operatesnear a zero direct voltage through a negative input full-bridge sub-module, and DC fault ride-through can be achieved without needing to block MMC. In order to ensure the safety of a converter valveduring the fault, the dissipative resistor is used to absorb energy during the fault so that a wind farm is disconnected with a grid during the fault and still maintains normal operation.

The invention discloses a low voltage ride-through control method of a doubly fed induction aero-generator, which is used when a power network has short circuit faults. The control method is characterized in that a rotor exciting voltage positive-sequence control current and a rotor exciting voltage negative-sequence control signal are respectively formed through limiting a rotor slip frequency current and a rotor (2-s) rated frequency current when the power network has faults, and a generator is utilized for realizing the attenuation of stator flux transient DC components and reducing the rotor side influences of the stator flux transient components, positive-sequence components and negative-sequence components. The control method has the advantages that no hardware protecting device is required to be added; under the condition that the power network has symmetrical and asymmetrical faults, the overcurrent occurrence of the rotor can be effectively restrained, and the safe operations of the generator and a rotor exciting converter are protected; in the process that the power network has the faults, the transient generator impact to the power network and a mechanical system can be effectively reduced; the normal operation of the generator can be fast recovered after the faults are removed, and the timely support to the power network can be realized.

The invention relates to a method for controlling the tension stability of wrap yarn during the wrap feeding and rolling process of a loom, comprising two parts, namely, wrap feeding and rolling control system hardware and a software program of a core controller. The hardware part comprises a main controller PLC, a touch screen, a tension sensor, an encoder, a servo driver, a servo motor and a speed reducer; and the software part employs a novel control algorithm, namely, single nerve cell self-adaptive PID algorithm. The control system is tested on the SAURER400-type rapier loom and good control effect is achieved, the tension fluctuation of wrap yarn of the loom is obviously improved, and the end breakage rate of wrap yarn is greatly decreased; besides, the control method is universal and has certain practical value both in reconstruction of the old loom and in algorithm research of the new loom.

The invention discloses a vertical ventilating shaft explosion door capable of automatically resetting after blast release and pressure relief, which belongs to the technical field of ventilating safety of coal mines and solves the problems that an explosion door fast depressurizes and releases blast air pressure and safely, automatically resets to close the mouth of a well and protects a ventilator device to be safely operated and normally ventilated when downhole blast impacts the mouth of a vertical ventilating shaft. A template pressure relief device and a skylight for a pilot pressure relief device capable of automatically resetting and closing are arranged on the top and a shell surface of the explosion door respectively; the explosion door is provided with four groups of hydraulic cylinders which synchronously move in two directions and are used for pulling and pushing the explosion door to automatically ascend and descend along the cylinders (tracks) and a hydraulic control and electric control system; the explosion door is also provided with a control device for operating a door body lifting hydraulic cylinder in a machine room and a pump station so as to realize natural ventilation and inverted ventilation operation; and a magnet steel sucking skylight is locked to realize inverted ventilation without manual operation. A composite technical system for operation and lifting control of the explosion door is safe and reliable, remote control operation is convenient and rapid, a ventilator is safely operated and ventilated during an accident, and an explosion-proof effect of the explosion door is achieved.

The present invention discloses a transmission line cleaning and bird repellent device. The device comprises an overhead track arranged along a transmission line, a travelling car arranged on the overhead track, a balance mechanism arranged at the bottom of the travelling car, an inspection robot arranged on the travelling car, a control center arranged on the travelling car and connected with the inspection robot, and a cleaning mechanism arranged on the travelling car and configured to clean the transmission line. Through cooperation of the overhead track and the travelling car, the inspection robot can move along the transmission line to monitor bird conditions on the transmission line and a tower, and a nest is cleaned through a nest pickup mechanism, and the transmission line cleaning and bird repellent device cannot have the inclination phenomenon when grabbing the nest through combination of the balance mechanism arranged at the bottom of the travelling car so as to protect the safety operation of the transmission line; and moreover, a natural bird repellent agent is employed to realize that birds cannot perform nesting again at a former address within a period of time.

The invention relates to a novel process for cleaning ice or snow covering a transmission line and a laser de-icing machine. In the process, a high-power laser is adopted to lead the laser to irradiate an iron tower and a cable, the intense laser radiation heating is used to lead part of the ice and snow covering connection transmission line to be molten, and the rest of ice and snow fall onto the ground. The laser de-icing machine consists of a power generator, a laser, a reflective mirror, a high-power collimation mirror and a fine regulating device which links the reflective mirror and the collimation mirror, wherein the power generator is connected with the laser through a cable; the laser and a transmitting frame are arranged on a base; an angle regulating device is fixed on the transmitting frame; and the angle regulating device can regulate the collimation mirror and the reflective mirror through linkage. The novel process has the advantages of high speed for cleaning the ice and snow covering the high-voltage transmission line, labor-saving performance and good security.

The invention relates to a centre drive dual-muld disc casting machine, which comprises a chute, casting discs, a quantitative casting system, sprinkling systems, waste anode hoists, lifter and water channel systems, spraying systems, a control cabinet and a hydraulic system; the dual-mold casting discs are fixedly arranged on a concrete foundation; the quantitative casting system is distributed between the dual-mold casting discs; each sprinkling system behind the quantitative casing system is arranged above eight empty molds of each casting disc along the disc rotation direction; each waste anode hoist is arranged at the outer side edge of each casting disc along with each sprinkling system; each lifter and water channel system is arranged at the outer side edge of each casting disc along with each waste anode hoist; and each spraying system is arranged at the outer side edge of each casting disc along with the lifter and water channel system. The centre drive dual-mold disc casting machine can be matched with a rotary metallurgical furnace, a fixed type anode furnace or other melting furnace and is wide in using range, high in automation degree, safe and reliable and strong in casting capability.

A method for measuring DC resistances of transformer windings comprises the following steps of: 1, connecting an AB-phase test wire of a transformer to a degaussing machine, starting the degaussing machine, changing the wire to a BC phase after the AB phase is degaussed, and repeating the above steps till all residual magnetisms in an iron core of the transformer is eliminated; measuring the DC resistance Rac of a low-voltage side winding ac and the DC resistance RAO of a high-voltage side winding AO by using a magnetism optimization method through a DC resistance testing instrument, and repeating the step 1 to eliminate the residual magnetisms in the iron core of the transformer; measuring the DC resistance Rab of a low-voltage winding ab and the DC resistance RBO of a high-voltage side winding BO by using the magnetism optimization method through the DC resistance testing instrument, and repeating the step 1 to eliminate the residual magnetisms in the iron core of the transformer; and measuring the DC resistance Rca of a low-voltage winding ca and the DC resistance RCO of a high-voltage side winding CO by using the magnetism optimization method through the DC resistance testing instrument, and repeating the step 1 to eliminate the residual magnetisms in the iron core of the transformer. According to the method for measuring the DC resistances of the transformer windings, excessive magnetizing inrush current of the transformer no-load closing is avoided and the safety operation of the transformer is protected.

The invention provides an identification method and device for the denial of service attack. The identification method for the denial of service attack comprises the following steps of obtaining the total amount of access requests sent to a target host within a first preset time period, and recording as a first request amount; judging whether the first request mount exceeds a threshold value which is obtained by calculating the page view of the target host; and if so, determining that the target host is subjected to the denial of service attack. According to the technical scheme disclosed by the invention, the total amount of the access requests sent to the target host within the preset time is used as a judgment target, the threshold value is obtained by the page view statistics of the target host to serve as a criteria to judge whether denial of service attack is received, the denial of service attack phenomenon is concluded to identify the denial of service attack so as to bring convenience to take corresponding measures, the identification accuracy of the denial of service attack is greatly improved, and the safety protection of the host is realized.

The invention discloses a heat pump hot water unit and a control method for water flow abnormality of the heat pump hot water unit. During unit defrosting running, the water outlet temperature of a second heat exchanger is detected, whether water flow is abnormal or not is judged according to the above temperature difference, and unit running is controlled. According to the range where the temperature difference is located, unit running is controlled, judgment is conducted in combination with the environment temperature situation, and unit running is controlled. Through the above control manner, whether water flow of the hot water unit is abnormal or not and whether the freezing risk happens or not can be effectively judged, unit freezing is prevented, and safety running of the unit is guaranteed.

The invention provides dam concrete surface abrasion-resistant coating and a coating method of the dam concrete surface abrasion-resistant coating. The coating is composed of three layers of coating namely a bottom layer, a middle layer and a surface layer from the surface of concrete outwards, wherein the coating at the bottom layer is epoxy cement gum with the thickness of 1-3 mm, the coating at the middle layer is low-viscosity epoxy resin adhesive with the thickness of 0.1-0.5 mm, the coating at the surface layer is polyaspartic acid ester polyurea which is 0.3-0.5 mm thick and is modified from nanometer materials, and the viscosity of the low-viscosity epoxy resin adhesive is 50-200 mPa.s. The dam concrete surface abrasion-resistant coating is resistant against the abrasion and damage of high-speed silt carrying water flow and bed load, effectively protects a dam to run normally, prolongs the safe service life of the dam, and protects the surface of dam concrete from fading or being pulverized and falling off. Meanwhile, the dam concrete surface abrasion-resistant coating is economical and practical, has good abrasion-resistant performance, adaptability and weather resistance, thereby meeting the requirements for abrasion-resistance of the surface of the dam concrete.

The invention discloses a three-phase load automatic balancing system in low voltage power supply area of transformer. The balancing system comprises a central controls and a phase changer. The central controller is arranged on the starting end of the branch while the phase changer is arranged at the terminal end of the branch and is connected with the load. The central controller and phase changer both adopt a three-phase four-wire method to be connected into the three-phase circuit; and communications are made between the phase changer and the central controller through power carriers. The three-phase load automatic balancing system in low voltage power supply area of transformer of the invention can effectively reduce the transformer loss and power line loss incurred from the imbalance of the three-phase load and overcomes the conditions with over-current at certain phase and low voltage at terminal end. In addition, since the system could switch phases automatically, power supply to the users does not have to be cut off. Consuming less power, the balancing system is also low in cost.

A bird-repellent device for an insulator of an electric power tower is characterized by comprising a U-shaped ring base, a fastening bolt, a locking gasket, a fastening nut, an anti-bird horn installation groove and anti-bird horns, wherein the U-shaped ring base is clamped on the electric power tower, the fastening bolt penetrates through a threaded hole in the bottom of the U-shaped ring base to abut against the locking gasket, the fastening nut is in match connection with the fastening bolt, the anti-bird horn installation groove is fixedly formed in the upper portion of the U-shaped ring base, and the anti-bird horns are fixedly arranged in the anti-bird horn installation groove. The bird-repellent device for the insulator of the electric power tower has the advantages that by means of the fixing mode of the U-shaped ring base, the protection radius can be enlarged effectively to be higher than 0.7 meter under the premise that a cross arm of the tower is unchanged, the insulator can be covered completely, birds are repelled, and lines can be used safely.

Provided is a turbine-generator shaft system torsional vibration protection method and device. The method includes the steps of collecting shaft system torsional vibration signals, determining the threat situation of the torsional vibration on the safety of units through a fatigue inverse time limit criterion (protection criterion I), a static instability criterion (protection criterion II) and a quick operation criterion (protection criterion III), and performing protection trip and warning to avoid more damage of the torsional vibration to a turbine-generator shaft system. The torsional vibration protection device comprises a speed sensor, a pulse input module (PI), a main control module (CM), a digital input module (DI), an analog input module (AI), a digital output module (DO) and a power supply module (POW). The speed sensor is connected to the pulse input module of the protection device through a cable. The protection device is in communication with a human machine interface (HMI) of a master station through Ethernet.

The invention relates to an electrical locomotive overvoltage suppression absorbing system, which comprises an overvoltage suppression absorbing device and an overvoltage suppression absorbing system control device, wherein the overvoltage suppression absorbing device and electrical locomotive core electric equipment are connected in parallel to a secondary side winding of an electrical locomotive high voltage transformer, and the overvoltage suppression absorbing device is used for suppressing and absorbing overvoltage generated by operation when an electrical locomotive passes a split phase; and the overvoltage suppression absorbing system control device is connected with the overvoltage suppression absorbing device and is used for controlling the action of the overvoltage suppression absorbing device when the electrical locomotive passes the split phase, and cutting off the overvoltage suppression absorbing device after the electrical locomotive passes a split phase area. In addition, the invention also discloses a control method for the electrical locomotive overvoltage suppression absorbing system. The Electrical locomotive overvoltage suppression absorbing system and the control method thereof can better solve the problem of operating overvoltage of the electrical locomotive, protect locomotive equipment and power supply system equipment from the influence of the overvoltage, and further improve the railway transportation safety.

The invention relates to an online monitoring system and an online monitoring method of the deflection of a portal crane girder, which belong to the technical field of deflection monitoring of the portal crane girder. The system comprises a reflecting device, a pulse distance measuring device, a data recording device and a data analyzing and processing device, wherein the reflecting device is installed on a lower cover plate of the portal crane girder, the pulse distance measuring device is installed on a support leg of a portal crane, the output end of the pulse distance measuring device is connected with the input end of the data recording device, and the output end of the data recording device is connected with the input end of the data analyzing and processing device. According to the system, the deflection change of the portal crane girder can be monitored in real time in the process of operation, the whole management level is increased, the safe operation of the crane can be greatly guaranteed, the personal safety of working personnel is protected, and accidents are avoided. Compared with the prior art, the system has the advantages of reasonable design, convenience in use and capability of stable long-term real-time monitoring and detection.

The invention relates to a gas compressor on-line characteristic analysis method based on the temperature control function of a gas turbine. The method is characterized by comprising the following steps: 1) performing rationality analysis on the differential pressure data of the intake manifold of the gas compressor and getting rid of some irrational data; 2) working out the air mass flow of the gas compressor according to the data sample acquired in step 1) and the size of the side section of the intake manifold, measuring and calculating the operating performance of the gas turbine by combining the data communication system (DCS) data, and adopting the operating data with small relative error as the modeling sample; 3) establishing a variable working condition model of the gas compressor comprising 3-1) establishing a temperature control rule model for the inlet guide vane (IGV) of the side section of the intake manifold of the gas compressor of the gas turbine; 3-2) establishing a pressure ratio model of the gas compressor; 3-3) establishing a flow model of the gas compressor; 3-4) establishing an intake resistance model of the gas compressor; and 3-5) establishing a gas compressor efficiency-flux characteristic curve based on the temperature control rule for the IGV of the side section of the intake manifold of the gas compressor. According to the invention, the air mass flow entering the gas compressor is limited through adjusting the blade angle of an adjustable guide vane, so that the purposes of protecting safe operation of the unit and improving the operating efficiency are realized.

The invention relates to a monitoring system, and especially relates to an antitheft type multifunctional wireless high-voltage cable sheath grounding current monitoring system. The system comprises a monitoring system, an acquisition system, a grounding box, a cable anti-cut-theft alarm and current transformers, wherein the acquisition system is respectively connected with a high-voltage cable A phase, a high-voltage cable B phase and a high-voltage cable C phase through the current transformers and the cable anti-cut-theft alarm , the high-voltage cable A phase, the high-voltage cable B phase and the high-voltage cable C phase are respectively connected with the grounding box through the cable anti-cut-theft alarm and the current transformers, the acquisition system is connected with the grounding box through the cable anti-cut-theft alarm, and the acquisition system sends information to the monitoring system through a wireless network. According to the invention, cable main insulation aging or defects, oversheath multipoint grounding faults, cross interconnection connection errors, direct grounding failure, protection grounding short circuits and grounding box thefts can be discovered, network nodes are regularly detected, and link faults are automatically diagnosed.

The invention discloses a control method and a control system for turbine compressors operated in parallel. The system comprises a load balance control part, a performance control part and an anti-surge control part. The method comprises the steps that the surge control deviation is calculated, according to the surge control deviation of all the units in a compression station and the average surgecontrol deviation, automatic load distribution of the units is achieved, the performance control and the load balance control are adopted and combined to control the rotating speed of turbines and the main performance parameters of the units, and the coupling relation between the performance control and the anti-surge control is eliminated. According to the method and the system, through the combined coordination control, the load distribution of the compression station units operated in parallel is optimized, the safety operation of the units is better protected, and the operation efficiencyof the units is maximized.

The invention discloses a transformer automatic phase-selection control method. The method comprises steps of: detecting voltage signals and current signals of a power grid in real time, and carrying out voltage zero point and reference current zero point extraction; receiving an action instruction for driving a transformer to act, and detecting whether the action instruction is a closing instruction or an opening instruction; according to the action instruction, detecting the on-off state of a circuit breaker contact for controlling the closing and opening of the transformer and the detecting voltage value of an energy storage capacitor for driving a circuit breaker, and judging whether the action requirements are met; if yes, executing the closing / opening operation; and if not, executing fault processing operation. According to the invention, the phase-selection automatic switching technology is used to control the transformer to complete the closing or opening operation at an optimum phase, so that shock-free smooth transition is realized in the transformer switching process.

The invention relates to a method and device for protecting safe operation of an intelligent device. The method comprises the following steps: monitoring the operational condition of a program on the intelligent device in real time; determining the program which is infected with virus according to the operational condition of the program; and interrupting the operation of the program which is infected with the virus, and replacing the operation with the back-up program which is not infected with the virus. According to the embodiment of the invention, an anti-virus function is realized on the premise of not establishing a virus feature library and not performing virus scanning; and the user operation is simplified, the anti-virus time is saved, the infringement of the intelligent device virus to the intelligent device is also effective prevented, and the safe operation of the intelligent device is protected.

The embodiment of the invention discloses a coal mill starting control method, system and coal mill starting equipment, relates to the field of starting control, and solves the problems caused by the excessive power of the coal mill in the prior art to the power grid and the motor. A technical problem with too much impact. The method in the present invention includes: before starting the coal mill, the coal mill starting equipment obtains the soft start parameters and interlocking signals for starting the coal mill; the coal mill starting equipment configures according to the soft start parameters; After the configuration is completed, the coal mill starting device determines whether the interlock signal meets the soft start condition; when it is determined that the soft start condition is satisfied, the coal mill starting device starts the coal mill according to the configuration. The embodiments of the present invention are mainly used for starting high-power equipment such as coal mills.

The invention relates to a coal ash and ash combined re-circulating system for preventing a boiler from being polluted. The coal ash and ash combined re-circulating system comprises a coal ash re-circulating system and an ash re-circulating system; the coal ash re-circulating system is used for leading coal ash out from an outlet of a de-duster and conveying to a coal milling machine; the ash re-circulating system is used for collecting ash of a boiler ash basin to a drier, crushing the dried ash, conveying the crushed ash to an ash storage cabin, and then conveying the ash from the ash storage cabin to the coal milling machine; the coal ash, the ash and raw coal powder are mixed and milled to require size in the coal milling machine according to a certain ratio and then sprayed in a hearth to be burnt; and active Na in smoke is gradually converted into insoluble Na salt with the flowing of the smoke. With the adoption of the coal ash and ash combined re-circulating system, the active Na in the smoke can be fixed, so as to generate the insoluble Na without being condensed and attached onto a convection heated surface; the dirt source is cut off; the convection heated surface is protected to safely operate; the operation time of the boiler is increased; and the benefits and power plants can be improved.

The invention discloses an oil purifier for oil used in an anti-explosion boat. The oil purifier for the oil used in the anti-explosion boat is characterized by comprising a bottom plate and an oil inlet portion, a filtering portion, an oil outlet portion and a control portion, wherein the an oil inlet portion, the filtering portion, the oil outlet portion and the control portion are arranged on the bottom plate. The oil inlet portion is provided with an oil pump which is used as oil power, and an oil inlet end of the oil pump is provided with an oil suction filter for primary filtering; and then the filter portion is sequentially provided with a protection filter, a coalescing separator and a fine filter so as to achieve multiple-layer filtering. By adopting the coalescing separator and combining the principle of comprehensive multiple-layer filtering, the oil purifier for the oil used in the anti-explosion boat is capable of achieving high-efficiency dehydration and meeting demands of fine separation and real-time separation, and has the advantages of being small in size, low in energy consumption, little in vibration, long in service life, easy and convenient to operate and maintain, low in operation cost, good in anti-explosion performance, safe and reliable and high in automatic degree.

The invention discloses a fuel gas distributed type energy supply device for cooling inlet air by using solar energy. The fuel gas distributed type energy supply device comprises an air filter (1), a gas turbine generator set (2), a double-pressure residual heat boiler (3) and a steam turbine generator set (4), and further comprises a solar heat collector (5), a heat collection system heat exchanger (6), a hot water storage tank (7) and an absorption type refrigerator (8) which are connected in sequence by a pipeline, wherein the hot water storage tank (7) is connected with the side of a tail heat exchanger of the double-pressure residual heat boiler (3) through a pipeline; and the absorption type refrigerator (8) is connected with the air filter (1). According to the fuel gas distributed type energy supply device, solar heat absorption type refrigeration is used for cooling inlet gas of a gas turbine and the output power and efficiency of the gas turbine are improved, and the fuel cost is saved; meanwhile, combined cycle residual heat of fuel gas and steam is sufficiently utilized and the economy of the system is improved; and the aims of complementary advantages, energy conservation and environmental friendliness of renewable energy sources and a fuel gas distributed type energy supply system can be realized.

The invention relates to the field of equipment manufacturing in the sludge treatment industry and provides an automatic pressure balancing device for a pressure filter. The automatic pressure balancing device comprises a thrust plate, filter plates and a pressing plate, wherein the thrust pate, the filter plates and the pressing plate are arranged in sequence. The pressing plate is connected with a main cylinder. A feeding pump and a water inlet pipe are connected with the filter plates. The automatic pressure balancing device is further provided with a material-oil conversion leather bag, a water-oil conversion leather bag, an oil cylinder and air cylinder assembly and a pressure stabilizing gas storage tank. A small oil cylinder is located on the upper portion of the oil cylinder and gas cylinder assembly, and a large oil cylinder is located on the lower portion of the oil cylinder and gas cylinder assembly. A piston rod of the small oil cylinder is connected with a piston rod of the large oil cylinder. Pre-pressing air cylinders are arranged on the left side and the right side of the large oil cylinder correspondingly. The piston rod of the large oil cylinder is connected with piston rods of the two pre-pressing air cylinders through a cross rod. Four cylinder bodies of the small oil cylinder, the large oil cylinder and the pre-pressing air cylinders are connected through a square frame. The automatic pressure balancing device is further provided with a proximity switch. The large oil cylinder is connected with the material-oil conversion leather bag and the water-oil conversion leather bag. The small oil cylinder is connected with the main cylinder. The pressure stabilizing gas storage tank is connected with the two pre-pressing air cylinders. By the adoption of the automatic pressure balancing device, the dynamic balance between the material pressure or water pressure and the oil pressure of the main cylinder is achieved, the situation that the filter plates are damaged under excessively high pressure is avoided, the structure is simple, and maintenance is convenient.

The invention relates to a method for preventing Stuxnet attacks, which comprises the following steps: step 1, a safety device is arranged in network communication, and the safety device is stored with a characteristic code; step 2, all data packets passing through the safety device are filtered and analyzed, and compared with the characteristic code; and step 3, the data packet is intercepted if the data packet is matched with the characteristic code. The method realizes a purpose of preventing attacks of Stuxnet through preventing downloading data packets of programs, analyzes the data packets passing through, intercepts the data packets which are matched with the characteristic code, terminates a download behavior of a PLC project, allows the data packets which are not matched with the characteristic code to pass through, realizes normal network communication, and ensures safe operation of an industrial Ethernet.

The invention relates to a twisting-resistant and stretching-resistant mobile type cable. The twisting-resistant and stretching-resistant mobile type cable comprises a plurality of cable cores containing conductors, wherein inter-core filler is arranged among the cable cores, exo-core filler is arranged outside the cable cores, a cable core isolation belt is arranged outside the exo-core filler, a sheathing layer is arranged outside the cable core isolation belt, the conductors are formed through bunching and stranding strand wires, and when the conductors are subjected to strand wire stranding, the directions of stranded wires of all layers are the same and the directions of the stranded wires of adjacent layers are opposite. A method for preparing the cable comprises the following steps of enabling part of the strand wires to be leftward and enabling part of the strand wires to be rightward during the bunching of the strand wires of the conductors, enabling the stranding direction of the stranded wires in each layer to be the same during the stranding of the conductors, and enabling the stranding direction of the stranded wires in an outer layer to be opposite to that in an inner layer, thereby obtaining the twisting-resistant and stretching-resistant mobile type cable. The cable provided by the invention is applicable to occasions that the cable is subjected to the action of stretching and repeated twisting during the operation of mobile electrical equipment; during the operation, the conductor cores of the cable do not break, the insulation is not damaged, and the cable cores do not deform.

The invention discloses a double-fed induction generator wind turbine Crowbar resistance design method based on a fuzzy membership function. The double-fed induction generator wind turbine Crowbar resistance design method comprises the following steps: according to an equivalent circuit model of a double-fed induction generator wind turbine in case of a power grid fault, and with the combination of a maximum fault current limiting condition and a direct-current bus capacitor voltage limiting condition, acquiring extreme value constraint relationship equations of rotor current and the Crowbar resistance as well as the direct-current bus voltage and the Crowbar resistance; respectively establishing fuzzy membership functions of the two constraint relationship equations according to the membership degree function concept of the fuzzy control principle; confirming the cross point of the two fuzzy membership functions in one same coordinate axis, thereby obtaining the Crowbar resistance corresponding to the cross point which is taken as the Crowbar resistance confirmed by using the method. By adopting the method, both the influence of over current of a rotor current transformer and the limiting condition of over voltage of direct current procedures of the rotor current transformer are considered, so that the security operation of the rotor current transformer of the double-fed induction generator wind turbine in a fault period is ensured to a maximum extent.