The invention discloses a method for predicting a passive interference resonant frequency of a short-wave frequency band of an ultra-high voltage transmission line. The method comprises the following steps: enabling a system comprising an ultra-high voltage transmission line array tower and an active antenna in a wide-area space to be equivalent to an electromagnetic open system; on the basis of the complex poynting theorem, calculating electric field energy and magnetic field energy of the electrically large electromagnetic open system of the ultra-high voltage transmission line to obtain mathematical representations of the electric field energy and the magnetic field energy of the electromagnetic open system; obtaining the mathematical representations of total electromagnetic field energy and an equivalent impedance matrix of the electromagnetic open system on the basis of voltage and current of an antenna feed port of the electromagnetic open system; and obtaining a frequency point, namely predicted resonant frequency, when the electric field energy and the magnetic field energy are in balance according to conditions of generating the resonance of the electromagnetic open system. According to the method, the generation of the resonant frequency can be accurately predicted from the essence of energy conversion of the electromagnetic open system of the ultra-high voltage transmission line; and the method can be applied to the prediction of the passive interference resonant frequency of the short-wave frequency band of the ultra-high voltage transmission line in future.

Method for predicting passive interference resonant frequency of short-wave frequency band of ultra-high voltage transmission line

The invention provides a water pressurizing device, and relates to the technical field of water pressurizing equipment. The water pressurizing device is designed to solve the technical problems that a water pressurizing device in the prior art usually has air compression due to air leakage and is not convenient to use. The water pressurizing device comprises a container body which is provided with an opening at the upper end part, wherein a gland is closely matched to the upper end part of the container body and can move up and down along the inner wall of the container body; a closed water accommodating cavity is formed between the gland and the container body; an elastic part is arranged in the water accommodating cavity, one end of the elastic part is fixedly connected with the gland, and the other end of the elastic part is fixedly connected with the container body; a water inlet and a water outlet are formed in the container body, and are communicated with the water accommodating cavity; and a water inlet valve is arranged at the water inlet, and a water outlet valve is arranged at the water outlet. The water pressurizing device is used for barreled water yielding, can be used for saving labor, and has relatively high water yielding efficiency.

Water pressurizing device

The invention provides a contact resistance calculating method and a device, which relate to the technical field of electric power. The method is used for determining the contact resistance between ahanging wire clamp and an internal ground wire. The method comprises the following steps: establishing a geometric model of the hanging wire clamp ground wire for the hanging wire clamp and the groundwire; A conductive bridge is arranged between the suspension wire clamp geometric model and the ground wire geometric model; The contact resistance between the hanging wire clamp and the ground wireis obtained by the simulation calculation of the electromagnetic field of the geometric model of the hanging wire clamp with the conductive bridge. By establishing a simulation model for calculating the contact resistance between the hanging wire clamp and the ground wire, and the electromagnetic field of the simulation model is simulated and calculated, The contact resistance between the hangingwire clamp and the ground wire can be obtained. The simulation calculation method can simulate the complex contact structure between the hanging wire clamp and the ground wire, and the calculation isconvenient and not affected by the external environment. It avoids all kinds of problems caused by the experimental method to determine the contact resistance, and improves the accuracy of determiningthe contact resistance.

Contact resistance calculation method and device

The invention discloses a radio frequency power acquisition and balancing method for a UHF band limit single-resonance electrically small antenna. The method comprises the steps that an antenna scattering model is constructed, an antenna scattering and absorption sectional area is calculated, scattering power and absorption power of the band limit antenna are calculated, and balance between the scattering power and the absorption power of the band limit antenna is realized. According to the method, a band limit single-resonance electrically small antenna scattering equivalent circuit model isconstructed by use of an antenna scattering theory based on a classic dipole antenna equivalent circuit model, the relation between antenna bandwidth and resonance frequency is analyzed, and a basis is provided for design and optimization of a backscattering communication system electrically small antenna.

Radio frequency power acquisition and balancing method for UHF band limit single-resonance electrically small antenna

The invention discloses a method and a system for determining a transmission line scheme based on low passive interference in a meter wave frequency band The method and the system comprise the following steps: expanding the transmission line scheme according to an initial transmission line scheme with a minimum height as an objective to determine a plurality of alternatives; Calculating the sum of the cross-sectional perimeters of all the sub-conductors corresponding to different conductor types in each alternative; For different tower types, the passive interference values of the corresponding alternatives are calculated in ascending order according to the summation of the cross-sectional perimeters of all subconductors corresponding to different conductor types until the passive interference value is greater than or equal to the preset critical threshold value The lowest economic cost of all the alternatives whose passive interference value is less than the preset critical threshold is selected as the final transmission line scheme The invention simplifies the workload of calculation, considers and selects the best transmission line scheme from multiple angles, remarkably reduces the problem of line cost increase caused by passive interference in the later period, and provides support for the erection design of the transmission line

A method and system for determining a transmission line scheme based on low passive interference in a meter wave frequency band

The invention relates to a device and a method for inhibiting secondary radiation of a medium-wave frequency band ultra-high voltage transmission line iron tower. The device for inhibiting the secondary radiation of the medium-wave frequency band ultra-high voltage transmission line iron tower comprises a metal stranded wire and a grounding device, wherein one end of the metal stranded wire is connected with the top of an iron tower and the other end of the metal stranded wire is connected with one end of a parallel assembly composed of an adjustable inductor L, an adjustable capacitor C and a short metal stranded wire in parallel at the position with a certain distance from the ground surface; the other end of the parallel assembly is connected with the grounding device. According to the method and the device for inhibiting the secondary radiation of the medium-wave frequency band ultra-high voltage transmission line iron tower disclosed by the invention, the secondary radiation of an ultra-high voltage transmission line to a radio station can be obviously inhibited, and the method and the device can be applied to passive jamming protection between the medium-wave frequency band ultra-high voltage transmission line and adjacent radio station in the future.

Method and device for inhibiting secondary radiation of medium-wave frequency band ultra-high voltage transmission line iron tower

The utility model provides a manual pressurized -water ware, includes through the removable casing of installing at the cask delivery port that unloads of snap ring device, is equipped with the hand head on the casing, the port is movable from top to bottom on the hand head accessible casing. Hand top of the head portion is equipped with and helps the pressure handle, help and press the handle to include the handle, handle lower extreme and quarter butt fixed connection are equipped with the external screw thread on the quarter butt. The overhead portion of hand center pin have the central screw hole that closes with the outer thread to match of quarter butt to the brill, the handle passes through quarter butt and hand head threaded connection. The overall dimension of handle be greater than the external diameter of hand head. The utility model discloses a setting helps the pressure handle, can make on the one hand that to press the operation more convenient, and on the other hand can play limiting displacement, prevents that the hand head from impressing the casing inside callipers and dying.

Cao Hongying

Papers

Method for predicting passive interference resonant frequency of short-wave frequency band of ultra-high voltage transmission line

Method and device for inhibiting secondary radiation of medium-wave frequency band ultra-high voltage transmission line iron tower

Manual pressurized -water ware