281 results about "Super low frequency" patented technology

The invention discloses a cable oscillation ultralow-frequency withstand voltage and partial discharge integrated test method and system, and relates to the technical field of distribution network cable detection, and the method comprises the steps: applying an oscillation ultralow-frequency voltage signal to a tested cable; the oscillation ultra-low frequency voltage signal is optimized and adjusted through a manifold learning algorithm and is used as a common excitation source for a withstand voltage test, dielectric loss detection and partial discharge detection; acquiring a voltage signal and a current signal of the tested cable under the excitation of the oscillation ultralow-frequency voltage signal, analyzing the deviation degree of the voltage signal and the current signal from the pre-established characteristic manifold, and extracting a dielectric loss characteristic signal and a partial discharge pulse signal; calculating a dielectric loss parameter based on the dielectric loss characteristic signal, determining a partial discharge position based on the partial discharge pulse signal, and generating a cable insulation state diagnosis report according to the dielectric loss parameter and the partial discharge position. According to the invention, the cable testing efficiency is improved, the equipment burden and the testing time are reduced, comprehensive evaluation and accurate fault positioning of the insulation state are realized, and a scientific basis is provided for preventive maintenance of a power system.

The invention discloses an ocean-ionized layer ultralow-frequency electromagnetic target detection simulation method based on ADI-FDTD and SIBC, and belongs to the field of computational electromagnetics. The ocean-ionized layer ultralow-frequency electromagnetic target detection simulation method comprises the following steps: introducing a frequency domain surface impedance boundary condition SIBC into an ADI-FDTD model; the ocean-ionosphere simulation model is used for carrying out ocean-ionosphere ultra-low frequency electromagnetic wave attenuation analysis on the ocean-ionosphere ultra-low frequency electromagnetic wave attenuation. According to the method, the frequency domain surface impedance boundary condition (SIBC) is combined with the ADI-FDTD method for the first time, so that the calculation space for analyzing the influence of the seabed on electromagnetic wave propagation is reduced. The calculation requirement is obviously reduced, and the efficiency is improved. In addition, the SIBC model based on the ADI-FDTD method can be used for simulating the scattering effect of electromagnetic waves on a high-conductivity and low-conductivity area interface.

The embodiment of the invention discloses a power cable withstand voltage evaluation method and device based on virtual simulation and a medium, and relates to the technical field of power cables, and the method comprises the steps: obtaining an operation process data set corresponding to an ultra-low frequency AC withstand voltage test through a big data technology, so as to determine a corresponding operation process task node sequence, acquiring cable structure data of the to-be-evaluated power cable and test equipment data corresponding to the ultralow frequency test equipment to construct a corresponding cable model and a test equipment model corresponding to the ultralow frequency test equipment; determining cable environment data of the to-be-evaluated power cable to establish a corresponding withstand voltage test virtual scene, and obtaining interaction action information of a test user in the withstand voltage test virtual scene; and performing test operation evaluation on the interaction action information based on the operation process task node sequence, and when a preset requirement is met, collecting simulation test parameters of the to-be-evaluated power cable, so as to determine a withstand voltage evaluation result of the to-be-evaluated power cable based on the simulation test parameters.

The invention provides a method for calculating a stable margin domain of isolated network operation regulation of a pumped storage power station, which comprises the following steps of: constructing a simulation model of the pumped storage power station in an isolated network mode, and deducing a comprehensive transfer function based on the model so as to obtain a margin stability characteristic equation of a pumped storage power station regulation system; by adjusting various parameters in the pumped storage power station, any two parameters are selected as coordinate axes in a rectangular coordinate system, and the stability margin domain of the pumped storage power station adjusting system under different stability margins is calculated by utilizing the Hellzz criterion; and fitting the time domain simulation curves of the pumped storage power station at different stability margin domain boundaries by adopting a power function. The method can quantify the stability margin of the power station when the power station encounters disturbance, identifies the stability boundary of the system under the ultralow frequency oscillation condition by analyzing the stability margin under different operation conditions, can effectively prevent and reduce the instability phenomenon, and improves the overall safety and reliability of the pumped storage power station.

The ultralow frequency sensor comprises a vibration detection unit, a power supply voltage stabilization unit and a signal conditioning unit, the power supply voltage stabilization unit is provided with a low dropout linear voltage regulator U20, a voltage converter U19 and a negative voltage regulator U21, and the low dropout linear voltage regulator U20 stabilizes an external power supply as a positive power supply VCC; the voltage converter U19 is used for converting positive voltage of an external power supply into negative voltage and outputting stable negative power supply VEE through the negative voltage stabilizer; the positive power supply VCC and the negative power supply VEE supply power to the signal conditioning unit; the signal conditioning unit comprises a high common mode rejection differential amplifier, a differential-to-single-ended amplifier, a band-pass filter and a differential output driver, a differential signal output by the vibration detection unit sequentially passes through the high common mode rejection differential amplifier, the differential-to-single-ended amplifier, the band-pass filter and the differential output driver, and then a differential voltage signal is output; the method has the advantages of high stability and reliability and the like.

The invention discloses a foldable piezoelectric vibration energy collector, and the collector comprises a cantilever beam which is provided with a fixed end at one end and a free end at the other end; the mass block is located below the cantilever beam, fixedly connected with the free end and used for adjusting the resonant frequency of the cantilever beam; the piezoelectric element is arranged on the cantilever beam; when the cantilever beam vibrates in the vertical direction, the piezoelectric element generates electric energy; the electric energy collecting element is electrically connected with the piezoelectric element and is used for collecting the electric energy; wherein the piezoelectric element comprises a plurality of piezoelectric layers, the plurality of piezoelectric layers are distributed at intervals in the vertical direction and are arranged in parallel, and every two adjacent piezoelectric layers are fixedly connected. Under the condition that a larger mass block or a longer cantilever beam does not need to be arranged, the energy conversion efficiency of the piezoelectric vibration energy collector in an ultralow-frequency vibration environment can be improved, and the miniaturization and wearable requirements of devices or electronic equipment can be met.

The invention provides a speed regulator control method and system for coping with ultralow frequency oscillation, and the method comprises the steps: obtaining the frequency data of a hydropower system in real time, and carrying out the filtering processing based on the original frequency data, thereby obtaining the filtering frequency data; constructing a first discrimination vector based on the filtering frequency data, determining a current oscillation occurrence probability based on the first discrimination vector, and determining whether to start an additional damping controller of the speed regulator based on the current oscillation occurrence probability; predicting frequency data of a plurality of time points in the future based on the current original frequency data, constructing filtering frequency data corresponding to each time point based on the predicted frequency data of the plurality of time points in the future, and constructing a second discrimination vector corresponding to each time point based on the filtering frequency data of each time point; and determining oscillation occurrence probabilities at multiple time points based on the multiple second discrimination vectors, and determining whether to start an additional damping controller of the speed regulator based on the oscillation occurrence probabilities at the multiple time points.

The invention relates to the technical field of intelligent power grids, in particular to an ultralow-frequency alternating-current ice melting device and a fault protection method. The method comprises the following steps: acquiring the line temperature and the output power of an ultralow-frequency alternating-current ice melting device at each moment in a preset historical time period of the current moment; further analyzing to obtain an ice melting efficiency coefficient at each moment, and constructing an ice melting efficiency coefficient sequence; obtaining all homotaxis sequence sub-segments and long-term change sub-segments; and finally, according to the change condition of the long-term change sub-segment and the local fluctuation condition of the ice melting efficiency coefficient sequence at the current moment, the output current frequency of the ultralow-frequency alternating-current ice melting device at the current moment is adjusted. By monitoring and evaluating the ice melting efficiency change condition of the ultralow-frequency alternating-current ice melting device, the ice melting effect in the adjacent time period of the current moment is analyzed and evaluated, then the output current frequency of the ultralow-frequency alternating-current ice melting device is accurately adjusted according to the ice melting effect, and the fault risk of the ice melting device is reduced while efficient and stable ice melting is kept.

The invention discloses a cold atom interference type low-frequency vibration measurement device and a measurement method, and solves the problems that the existing cold atom interference gravimeter measurement equipment is limited by the performance of a vibration sensor, the compensation precision is insufficient, timing calibration is needed, and the measurement precision is low. And measurement errors generated by gravity and ultralow-frequency vibration cannot be effectively separated from a measurement result of the cold atom interference gravimeter, namely, decoupling of two measurement parameters is realized, and cold atom interference measurement of low-frequency vibration is realized. The measuring device comprises a Raman laser output system, a vacuum cavity, a sensitive axis converter and a vibration detection reflecting mirror, the Raman laser output system outputs two pieces of Raman laser which have the same polarization state and are both circular polarization states; the low-frequency vibration is transmitted to the liquid crystal phase modulator through the vacuum cavity for polarization state conversion, and then is reflected to the liquid crystal phase modulator or the vibration detection reflector through the polarization splitting prism, so that the interference type low-frequency vibration of the cold atoms is measured, and decoupling of the two is realized.

Anti-vibration units are provided for vibration suppression in multiple directions. The anti-vibration units may have an X-shaped structure as part of its support structure. The anti-vibration units can work for ultra-low frequency vibration isolation in three directions in a passive manner. The anti-vibration units can achieve a flexible nonlinear stiffness, which contains zero or quasi-zero stiffness, negative stiffness and positive stiffness. A smooth multi-equilibria state is also achievable. Compared with traditional spring-mass-damper (SMD) and typical QZS systems, the provided anti-vibration units can have an enhanced QZS range of larger stroke with guaranteed loading capacity, and can also achieve a lower resonant frequency with a lower resonant peak. At least some embodiments of the anti-vibration units may include a new and innovative arrangement of components that enables a more compact design than typical anti-vibration systems.

The invention provides a collaborative optimization method of a mixed water electrolysis hydrogen production system considering seasonal wind and light fluctuation. The method comprises the following steps of: analyzing a wind-solar power frequency spectrum by adopting a variational mode decomposition algorithm, and extracting three intrinsic mode function components of ultrahigh frequency, transition frequency band and ultralow frequency; establishing a multi-time-scale collaborative optimization framework comprising a seasonal scheduling layer, an intra-day optimization layer and a real-time control layer; the ultra-low frequency component is distributed to an alkaline electrolytic bath, and the ultra-high frequency component is distributed to a proton exchange membrane electrolytic bath; an electric-thermal-life multi-field coupling efficiency optimization model is constructed, and multi-objective optimization of efficiency maximization and life loss and operation cost minimization is achieved; and an equipment switching critical point calculation method based on an efficiency curve second derivative and a gradient protection strategy are adopted. The method can effectively improve the adaptability of the system to seasonal fluctuation, the operation economy and the service life of equipment.

The invention relates to the technical field of vibration control, and particularly provides an ultralow-frequency passive self-adaptive tuning vibration absorber based on a string-mass system, which comprises a mechanical sensing assembly, a mechanical driving assembly, a mechanical transmission assembly and a tuning vibration absorption assembly which are arranged on a target structure, the mechanical sensing assembly and the mechanical driving assembly are correspondingly arranged, and the mechanical sensing assembly is used for sensing vibration of a target structure and can generate relative movement; the mechanical driving assembly is connected with the mechanical transmission assembly, and the mechanical driving assembly drives the mechanical transmission assembly to work based on relative motion generated by the mechanical sensing assembly; the mechanical transmission assembly is connected with the tuning vibration absorption assembly. The vibration absorber is wide in application range, compared with an existing self-adaptive tuning vibration absorber, the vibration absorber has the advantages that external power supply driving is not needed, the structure is simple, ultralow-frequency vibration control can be achieved, and effective control over broadband even multi-order modal vibration is achieved through a pure mechanical structure.

The invention provides a signal automatic patrol and abnormity intelligent analysis method and device based on a centralized control center. By constructing a patrol logic control mechanism and combining real-time data acquisition and operation trend analysis, abnormal states and potential fault symptoms occurring in the operation process of the power equipment are identified, periodic or real-time analysis is performed on the operation condition of a target object, and a patrol report and an abnormal grade division result are automatically generated. The method can achieve the intelligent recognition and response of ultralow frequency oscillation, signal fluctuation and other characteristic problems in new power system scenes such as new energy access, facilitates the improvement of the intelligent level of operation monitoring of a centralized control center, and improves the early warning capability of equipment faults and the accident response efficiency. And the operation risk and the system disturbance caused by monitoring omission are avoided.

The invention provides a magnetic levitation type mechanical damping device for ultra-low-frequency vertical vortex-induced vibration of a super-large-span bridge girder, and belongs to the field of low-frequency structure vertical vibration control. The device comprises a mounting base, a top connecting plate, a spring device, a mass block, a magnetic force compensation unit, a damping device and a plurality of guide devices, the multiple guide devices are installed between the installation base and the top connecting plate, the mass blocks are installed on the peripheries of the multiple guide devices, the magnetic force compensation units are installed on the peripheries of the mass blocks, and the mass blocks can vertically move along the guide devices under the action of the magnetic force compensation units. Wherein the spring device and the damping device are vertically arranged between the top connecting plate and the mass block in parallel. The core innovation of the invention lies in providing a magnetic active compensation mechanism, and through a gradient magnetic field with a special configuration, approximately constant upward buoyancy is generated in a TMD vertical motion stroke, so that the mass block is always in a quasi-suspension state, and complete gravity unloading and dynamic tuning separation are realized.

The invention discloses a power cable insulation state detection system based on ultralow frequency dielectric loss. The system comprises an excitation signal generation module, a signal acquisition and conversion module, a data processing and analysis module, an insulation state evaluation module, a database storage module and a man-machine interaction module. The signal acquisition and conversion module acquires output voltage and current signals and converts analog signals into digital signals; the data processing and analysis module processes signals based on a system identification theory, establishes an equivalent mathematical model, analyzes data, calculates dielectric parameters and provides a basis for evaluation; the insulation state evaluation module combines historical data with a standard threshold value, designs an evaluation algorithm, analyzes dielectric parameter changes, judges the cable insulation problem, sets a parameter alarm mechanism and automatically gives an alarm when the threshold value is exceeded; according to the method, the detection process is optimized based on the identification theory, ultralow frequency key frequency points are covered, the result precision is ensured through mathematical modeling and analysis, the test time is effectively shortened, and the test result accuracy is high.

The invention relates to the technical field of power grid safety, in particular to a photovoltaic vector margin method active control parameter setting oscillation suppression method and system. Selecting a rotor loop as a forward channel link to obtain a compact form Heffron-Phillips model of a system considering photovoltaic grid connection; the method comprises the following steps: carrying out order reduction simplification on a compact form Heffron-Phillips model of a system considering photovoltaic grid connection at an ultra-low frequency oscillation frequency point; applying a vector margin method to give a frequency domain stability margin of the system; establishing a photovoltaic active power control link parameter setting optimization model; and solving the optimization model to obtain a designed active control link parameter value. According to the method, the frequency domain stability margin of the multi-input-multi-output photovoltaic grid-connected power system under the ultralow frequency oscillation can be given, the mathematical relationship of the stability margin is simple, and the effect of suppressing the ultralow frequency oscillation by carrying out optimization design on photovoltaic power generation active control link parameters is given.

The invention relates to an ultra-low-frequency alternating current weak signal current measuring instrument and a measuring method, which are used for measuring parameters of ultra-low-frequency weak alternating current, and comprise a conversion device used for converting the ultra-low-frequency weak alternating current to be measured into low-frequency voltage; the reference voltage chip is used for providing stable reference voltage for the analog-to-digital conversion chip; the analog-to-digital conversion chip is used for converting the low-frequency voltage into a digital signal by comparing the low-frequency voltage with a reference voltage; and the control module is used for resolving the voltage amplitude and frequency of the ultralow-frequency weak alternating current according to the digital signal and the information of the conversion device. Current-voltage conversion is realized by adopting a virtual ground operational amplifier and a trans-impedance mode, the converted signal is an alternating-current voltage signal which has the same frequency as a to-be-measured current signal and is in a certain proportion, an error introduced by an alternating-current impedance component of a feedback resistor can be negligible, the linearity is good, the frequency consistency is good, and the accuracy is high. And the method is more suitable for measuring ultralow-frequency weak alternating current to be measured.

The utility model discloses a quasi-zero stiffness vibration isolation device which comprises a support, a positive stiffness vibration isolator and a negative stiffness mechanism. The positive stiffness vibration isolator comprises a first support and a second support, a first supporting column is arranged on the first support, and the second support is connected to the first supporting column in a sliding mode. The negative stiffness mechanism comprises an unsprung synchronization unit and a sprung synchronization unit, the unsprung synchronization unit is provided with a second supporting column, and the second supporting column is coaxially located above the first supporting column; an elastic damping structure is arranged between the first support and the second support, and a plurality of negative stiffness elements are arranged between the unsprung synchronization unit and the sprung synchronization unit to form vertical negative stiffness. The utility model relates to the field of vibration reduction and isolation, realizes that the dynamic rigidity is low or is close to zero in a static balance state, solves the difficult problem when a traditional linear vibration isolation system isolates low-frequency or ultralow-frequency vibration, reduces the initial vibration isolation frequency, enlarges the vibration isolation frequency range, and improves the vibration isolation efficiency of the system.

The present invention proposes an optimal controller design method for an ultra-low frequency vibration isolation system, the method comprising the following steps: establishing a dynamic model of the ultra-low frequency vibration isolation system in the present invention, deriving the state space equation of the ultra-low frequency vibration isolation system; allocating weight matrices Q and R according to the objective function of the optimal quadratic algorithm and the control target of the vibration isolation system; deriving the control force model of the optimal controller according to the weight matrix Q and R and in combination with the state space equation of the vibration isolation system, substituting the control force into the control loop to obtain a complete optimal controller and obtaining a better control effect by optimizing the weight allocation of the Q and R matrices. Thus, the active control performance of the ultra-low frequency vibration isolation system is improved. The method is low-cost, simple and easy to use, and effectively improves the vibration isolation performance of the ultra-low frequency vibration isolation system.

This invention relates to a method for measuring the stability margin of a constant-temperature hot-wire anemometer based on in-situ open-loop frequency characteristics, belonging to the field of fluid measurement and automatic control technology. The method disclosed in this invention includes the following steps: S1. Connecting an ultra-low frequency low-pass filter to the closed-loop circuit to form an in-situ open-loop system with a DC closed loop and an AC open loop; S2. Injecting a sweep frequency excitation signal E at the bias circuit. stimu And measure the output response E of the amplifier circuit. a By comparing the amplitude ratio and phase difference of the two, the open-loop frequency response G of the system under actual operating conditions of the hot wire is obtained. open (jω); S3. According to G open (jω) Obtain the phase margin of the system and determine its stability. This invention proposes a new method for measuring the stability margin of a constant-temperature hot-wire anemometer, transforming the complex system stability problem into a measurable and analyzable open-loop frequency characteristic stability margin problem, providing a direct and reliable engineering basis for the circuit design of constant-temperature hot-wire anemometers.

A kind of atomic gyroscope pumping rate stable composite control method based on phase reshaping extended state observer and power approaching sliding mode control.Aiming at the problems that standard linear extended state observer has steady-state estimation error under the action of ramp disturbance, disturbance estimation phase lag and it is difficult to balance between observation bandwidth improvement and noise sensitivity, a composite corrector composed of lead network and lag network is cascaded at the output end of disturbance estimation of extended state observer, the disturbance estimation channel is shaped in frequency domain, phase lead is provided in mid-frequency band to reduce compensation delay, amplitude lag characteristic is used to suppress high-frequency noise, and parameter constraint design is used to realize zero-error estimation of ramp disturbance;At the same time, a power approaching sliding mode controller is constructed to improve the adaptability to the nonlinear, internal and external coupling and parameter uncertainty of atomic gyroscope system, and the phase reshaping extended state observer is combined to effectively estimate and feed forward compensate the lumped disturbance, so as to improve the stability and accuracy of pumping rate control.The present application can balance dynamic anti-disturbance performance, steady-state control accuracy, convergence speed and noise robustness without significantly improving the observation bandwidth, and is suitable for atomic gyroscope precision control system affected by ultra-low frequency slowly varying disturbance.

An ultra-low-frequency six-degree-of-freedom active vibration isolator based on air floatation comprises a panel, four vibration isolators, a base and a controller, the four vibration isolators are located at the four corners of the top of the base respectively, the tops of the vibration isolators are connected with the top corners of the bottom of the panel, each vibration isolator comprises a top plate and a main air chamber, and the bottom of each main air chamber is connected with a bottom air chamber through an air hole; four side air chambers are installed on the periphery of the main air chamber, a piston A is installed in the main air chamber, the top of the piston A is connected with the top of the main air chamber through a diaphragm, a supporting rod A is installed in the piston A, a spherical rotor is installed at the top of the supporting rod A, and the spherical rotor is in contact connection with the middle of the bottom of the top plate. The bottom of the supporting rod A is connected with the bottom side in the piston A through a ball. The vibration isolation belt of the system is wide, six-degree-of-freedom vibration control of 0.1 Hz to 300 Hz can be achieved, the bearing capacity is large, and the bearing requirement of a 10000kg precise instrument can be met.

The present invention relates to a combined polarized ultra-low frequency curved disk transducer and a preparation method thereof. The two transducer components are opposed to each other with the radiation surface facing outward, and an air cavity is provided between the two transducer components. A connecting cable is provided for the two transducer components, and a combined polarization component is provided for any of the transducer components. The present invention combines tangential polarization with thickness polarization. On the basis of conventional thickness polarization, tangential polarization is added to compensate for the vibration displacement at the outer position to obtain a better vibration mode and a larger vibration displacement. By changing the distribution of the piezoelectric elements, the equivalent distribution space of the active driving material is increased. While reducing the resonant frequency of the curved disk transducer, it has a higher transmission voltage response and improves the transmission capability of the transducer. A new implementation method of tangential polarization is proposed to solve the short circuit problem between the element and the metal plate, ensure the adaptability of the vibration mode between the materials, and make the entire transducer have a better vibration mode.

The application provides a cable insulation aging evaluation method based on high-voltage frequency domain dielectric response characteristic quantity, under the condition that the insulation electric field intensity is 0.5kV / mm-1kV / mm, an ultralow frequency sweep test signal is applied to the measured cable under three different voltages, and the dielectric loss tangent value frequency domain response curve corresponding to each voltage level is obtained; at least two dielectric characteristic quantities are calculated based on the frequency domain response curve, the dielectric characteristic quantities include a first characteristic quantity representing the discrete degree of the dielectric loss tangent value under different voltages, and a second characteristic quantity representing the frequency domain integral characteristic of the dielectric loss tangent value under the highest test voltage; based on a preset correlation evaluation model taking the cable insulation mechanical performance aging index as a benchmark, the insulation health state score of the measured cable is calculated by combining the dielectric characteristic quantities, and the insulation aging state is determined according to the health state score.

The invention discloses an ultra-low frequency conduction acoustic system based on reverse installation and a sapphire reflection structure, and belongs to the field of audio acoustics, the ultra-low frequency conduction acoustic system comprises a moving coil unit, the sapphire reflection structure and a sound tube, the moving coil unit is reversely installed on the inner side of an earphone surface cover, and a vibrating diaphragm faces the direction away from a sound outlet; sound waves are reflected to the reflecting surface of the stone surface cover of the sapphire reflecting structure through the rear cavity and then are transmitted to the sound outlet through the sound tube; the surface cover of the sapphire reflection structure is of a customized special-shaped structure, is accurately matched with the reflection angle of the rear cavity, and has optical-grade surface smoothness; the moving coil unit is combined with a plurality of moving iron units and static units, and the moving iron units and the static units adopt a forward sound wave conduction mode; the reverse sound wave path is prolonged and reflected by the high-hardness sapphire, and the low-frequency quantity sense is sufficient and distinct in hierarchy; an independent low-frequency sound path can be realized without increasing the volume of the earphone; low frequency and medium-high frequency are physically isolated, and mutual interference is reduced.

A system and method include transmitting a signal according to a set of frequencies. A frequency range associated with the set of frequencies is from about 300 Hz to about 30 MHz. The system and method include sensing an electromagnetic field based on transmitting the signal according to the set of frequencies and determining a distortion in association with sensing the electromagnetic field. The system and method include identifying frequencies at which the magnitude of the distortion is less than the threshold value. The system and method include transmitting the signal according to one or more of the identified frequencies and providing navigation information associated with an environment in response to transmitting the signal.

The invention discloses a cable insulation state evaluation method based on rapid ultralow frequency dielectric response, comprising the following steps: applying excitation voltage to a cable to obtain an ultralow frequency dielectric spectrum and a U-I hysteresis curve; extracting a characteristic quantity representing the insulation aging of the cable as a criterion for distinguishing the insulation aging type of the cable; respectively setting related index quantities of different cable insulation aging types; constructing an evaluation index system; determining the subjective weight and objective weight of each index in the evaluation index system by adopting an analytic hierarchy process and an entropy weight method respectively, and carrying out combined weighting to determine a combined weight; performing logarithmic correction on the combined weight; constructing a scoring model; evaluating the insulation state of the cable based on a scoring model to obtain an operation state scoring result of the cable; the operation condition of the cable line can be accurately mastered, the operation and maintenance cost is reduced, the test and evaluation time is effectively saved, stable operation of the power cable is ensured, the line failure rate is reduced, and indirect benefits are generated.

The utility model provides a magnetic bar coil and a laminated ultra-low-frequency high-voltage generator, and relates to the technical field of electron and high-voltage measurement. The winding structure of the coil on the periphery of the magnetic bar is that the two ends are densely wound and the middle is sparsely wound; the periphery of the magnetic bar wound with the coil is sleeved with an insulating tube; the magnetic bar is connected with a plurality of high-voltage lamination units of the lamination type booster in a magnetic field coupling mode. The coil is wound on the periphery of the magnetic bar according to the structure that the two ends are densely wound and the middle is sparsely wound, so that the magnetic flux of the whole body of the magnetic bar is equal, the voltage uniformity of each high-voltage laminated unit is improved, the ultralow-frequency high-voltage generator magnetic bar coil can stably and reliably work, and the high-voltage laminated units are prevented from being damaged due to overvoltage.

The invention relates to a vibration isolation device and a gravitational acceleration measuring instrument. The vibration isolation device comprises a primary vibration isolation module and a secondary vibration isolation module. The primary vibration isolation module comprises two fixing structures arranged in the gravity direction in a spaced mode and a floating body structure located between the two fixing structures. The two fixed structures are respectively provided with a first permanent magnet so as to generate a magnetic field between the two fixed structures, and the floating body structure is provided with a second permanent magnet so as to enable the floating body structure to suspend in the magnetic field; the secondary vibration isolation module comprises a displacement measuring unit and an adjusting unit, the displacement measuring unit is used for measuring relative movement information between the fixed structure and the floating body structure, and the adjusting unit is used for adjusting relative displacement between the fixed structure and the floating body structure according to the relative movement information. According to the scheme, the vibration isolation device has a long local oscillation period and has a good inhibition effect on ultralow-frequency vibration.

The application provides a forming and assembling method of an ultralow-frequency kicker model cavity, and aims at solving the technical problems that a large-diameter copper pipe cannot be directly wound outside an insulating support body made of polytetrafluoroethylene material by a high-temperature heating method, and a large-diameter copper coil cannot be accurately inserted into a slot during forming and assembling of an existing ultralow-frequency kicker model cavity. The application first completes preparation of the large-diameter copper coil by means of a tool, and then sequentially inserts the insulating support body designed as a split structure into the large-diameter copper coil. Meanwhile, the large-diameter copper coil is fixed on the insulating support body by a clamp, the resilience of the large-diameter copper coil is effectively controlled, accurate nesting and fixing of the insulating support body and the large-diameter copper coil are realized, and the accuracy of the resonance frequency of the ultralow-frequency kicker model cavity is ensured. The forming and assembling method of the ultralow-frequency kicker model cavity is convenient, has high reliability, and can accurately realize the target frequency of the ultralow-frequency kicker model cavity.