CN104730437A - Corona characteristic measuring system and method for transmission lines in corona cage - Google Patents

Abstract

The invention relates to a corona characteristic measuring system and method for transmission lines in a corona cage. Measuring parameters comprise the number of ultraviolet photons, audible noise and radio interference. The measuring method includes the steps of measuring the number of the ultraviolet photons and measuring the audible noise and the radio interference. The method includes the steps that the movable small corona cage is designed and manufactured, a corona test is conducted, and the number of the ultraviolet photons, the audible noise and the radio interference are measured through an ultraviolet instrument, a noise level meter and a radio receiver which are installed in fixed positions. The method is short in test period, conditions are controllable, and the corona characteristics of the transmission lines under different electric field intensities can be conveniently researched.

Description

Transmission line of electricity corona characteristic measuring system in a kind of corona cage and method

Technical field

The present invention relates to the transmission line of electricity corona characteristic measuring system in a kind of corona cage and method.

Background technology

Along with the raising of power transmission engineering electric pressure, the corona characteristic of transmission line of electricity is more and more important, and it is directly connected to the type selecting of wire, and line optimization designs, construction investment and environmental protection.

At present, site test line segment can be adopted to realize the research of transmission line of electricity corona characteristic, the cogency that the experimental study most of true type wire is certain.But, impact is there is in weather condition on the corona characteristic of circuit, the environment, weather etc. of site test line segment are uncontrollable, be difficult to the test condition reaching needs, conductor corona characteristic is studied by means of only site test line segment, very difficult, it is irrational for relying on site test line segment to carry out research completely, utilizes corona cage then can make up the deficiency of test line segment.The function of corona cage, mainly by carrying out the corona characteristic test of multiple split conductor, obtains the test figure of various wire in the short time; Selecting representative split conductor, test section is utilized to carry out real model experiment; Corona characteristic in conjunction with corona cage inside conductor and test section is tested, research transmission line of electricity corona characteristic.

Summary of the invention

The present invention is in order to solve the problem, propose the transmission line of electricity corona characteristic measuring system in a kind of corona cage and method, this method is by measuring ultraviolet light subnumber, audible noise, radio interference, the corona characteristic of research transmission pressure under different electric field intensity, has simple, that the test period is short and condition is controlled advantage.

To achieve these goals, the present invention adopts following technical scheme:

Transmission line of electricity corona characteristic measuring system in a kind of corona cage, comprise corona cage, ultraviolet imager, radio interference receiver and sound meter, wherein, corona cage is arranged in screening cage, power transmission line introduces corona cage, and power transmission line one end connects power supply, other end access radio interference receiver, the horizontal direction of power transmission line sustained height is provided with ultraviolet imager and sound meter, ultraviolet imager moves along the horizontal direction of power transmission line and observes.

The distance of described ultraviolet imager and power transmission line is 5-7m.

The distance 3.5-5m of described sound meter and power transmission line.

Described AC power connects trap, and trap connects power transmission line, and trap connects interference current coupling circuit by high-voltage capacitance, and radio interference receiver connects interference current coupling circuit.

Described ultraviolet imager is the DayCor Super type that Ofil company of Israel manufactures, and sound level counts the BK2250 that Denmark produces.

Based on a measuring method for above-mentioned measuring system, comprise the following steps:

(1) connecting test system and power transmission line loop;

(2) progressively raise the voltage be applied on wire, and continue to boost to strong degree of discharge, progressively reduce voltage afterwards, to initial voltage level, record corresponding photon count rate respectively for each steady point of discharge;

(3) according to the pressuring method of step (2), to every root sample repeatedly, the mean value of the photon count rate of each corona point is as the final value of the final photon count rate of each corona point;

(4) according to the pressuring method of step (2), setpoint frequency component in ground unrest acoustic pressure before the bloom of record wire, after wire bloom, under each voltage, the mxm. of difference recording noise acoustic pressure setpoint frequency component and minimum, finally obtain the audible noise mean value that wire samples corona discharge produces, the present invention's corona audible noise setpoint frequency component distinguishes ground unrest;

(5) according to the pressuring method of step (2), the radio interference level of radio interference under contrast frequency before and after bloom under each electric pressure is measured;

(6) change the swoon acoustic pressure of audible noise setpoint frequency component of the tracerse point recorded, screening valid data, calculate radio interference level in corona cage.

In described step (6), the concrete grammar that the acoustic pressure of swooning audible noise setpoint frequency component to the tracerse point recorded is changed is: the acoustic pressure of conductor corona audible noise setpoint frequency component is converted to the decibel value with 20uPa into benchmark, and its conversion formula is: wherein P is the acoustic pressure (unit is Pa) of conductor corona audible noise setpoint frequency component, P _dBfor the wire audible noise setpoint frequency component represented with decibel.

In described step (6), the concrete grammar of screening valid data is: for the radio interference value recorded, according to regulation in GB/T7349-2002 " high voltage overhead power transmission line, transformer station's radio interference method ", electromagnetic environment field intensity at least should than from the low 6dB of the radio interference field intensity of measurand, first measurement data is screened according to the method, draw valid data, and finally show that in corona cage, radio interference level Ψ can be expressed as:

$\mathrm{\Ψ}=U_{\mathrm{EMI}}-20\lg (Z_{\mathrm{eq}}\·\sqrt{l}\·K)+20\lg \left(\frac{2\mathrm{\π}{\mathrm{\ϵ}}_0}{C_0}\right)\mathrm{dB}$

In formula, the unit of Ψ becomes dB, U _eMIfor the radio interference voltage measured, Z _eqfor the equivalent resistance of measuring circuit under contrast frequency, l is corona cage length, and K is measuring circuit correction factor, C ₀unit length ground capacitance, ε ₀for permittivity of vacuum.

Beneficial effect of the present invention is:

The method test period is short, and condition is controlled, is convenient to the corona characteristic of research transmission pressure under different electric field intensity.

Accompanying drawing explanation

Fig. 1 is structural representation of the present invention;

Fig. 2 is that radio interference of the present invention measures wiring schematic diagram;

Fig. 3 is ultraviolet imager shooting effect figure of the present invention.

Embodiment:

Below in conjunction with accompanying drawing and embodiment, the invention will be further described.

As shown in Figure 1-Figure 3, transmission line of electricity corona characteristic measuring method in a kind of corona cage, it comprises the following steps: (1): movable corona cage is positioned over high-potting hall, the sampling wire of actual transmission line of electricity is installed, simultaneously by high-voltage connection lead-in conductor, ultraviolet device is placed on distance of wire vertical range 5m place, height maintains an equal level with wire, move along wire horizontal direction in observation process and observe, sound meter is positioned over apart from outside wire 3.5m, height maintains an equal level with conductor height, and radio interference receiver is arranged on test loop;

(2): progressively raise the voltage be applied on wire, and continue to boost to strong degree of discharge, progressively reduce voltage afterwards, to initial voltage level, corresponding photon count rate is recorded respectively for each steady point of discharge;

(3): according to second step pressuring method, repeat 3 times to every root sample, the mean value of the photon count rate of each corona point is as the final value of the final photon count rate of each corona point;

(4): pressurize by second step pressuring method, 8kHz component in ground unrest acoustic pressure before the bloom of record wire, after wire bloom, under each voltage, the mxm. of difference recording noise acoustic pressure 8kHz component and minimum, finally obtain the audible noise mean value that wire samples corona discharge produces;

(5): being converted to the acoustic pressure of conductor corona audible noise 8kHz component with 20uPa is the decibel value of benchmark, and its conversion formula is: wherein P is the acoustic pressure (unit is Pa) of conductor corona audible noise 8kHz component, P _dBfor the wire audible noise 8kHz component represented with decibel;

(6): by the pressurization of second step pressuring method, measure the radio interference value under each electric pressure before and after bloom, interference value be converted to radio interference level Ψ, can be expressed as:

$\mathrm{\Ψ}=U_{\mathrm{EMI}}-20\lg (Z_{\mathrm{eq}}\·\sqrt{l}\·K)+20\lg \left(\frac{2\mathrm{\π}{\mathrm{\ϵ}}_0}{C_0}\right)\mathrm{dB}$

In formula, the unit of Ψ becomes dB, and UEMI is the radio interference voltage measured, Zeq is the equivalent resistance of measuring circuit under 0.5MHz frequency, and this is 24.9 Ω, l is in the present invention corona cage length, K is measuring circuit correction factor, is 0.51, C concerning this corona cage ₀for 12.82pF/m, permittivity of vacuum ε ₀be 8.854187818 × 10 ^-12f/m.

In Fig. 3, be react the later ultraviolet figure of corona cage inside conductor bloom, the photon number in this moment can be reflected from figure, by the photon number under different voltage, utilize tangent method, the discharge inception voltage value of wire can be calculated.

By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various amendment or distortion that creative work can make still within protection scope of the present invention.

Claims (7)

1. the transmission line of electricity corona characteristic measuring system in a corona cage, it is characterized in that: comprise corona cage, ultraviolet imager, radio interference receiver and sound meter, wherein, corona cage is arranged in screening cage, power transmission line introduces corona cage, and power transmission line one end connects power supply, other end access radio interference receiver, the horizontal direction of power transmission line sustained height is provided with ultraviolet imager and sound meter, ultraviolet imager moves along the horizontal direction of power transmission line and observes.

2. the transmission line of electricity corona characteristic measuring system in a kind of corona cage as claimed in claim 1, is characterized in that: the distance of described ultraviolet imager and power transmission line is 5-7m.

3. the transmission line of electricity corona characteristic measuring system in a kind of corona cage as claimed in claim 1, is characterized in that: the distance 3.5-5m of described sound meter and power transmission line.

4. the transmission line of electricity corona characteristic measuring system in a kind of corona cage as claimed in claim 1, it is characterized in that: described AC power connects trap, trap connects power transmission line, trap connects interference current coupling circuit by high-voltage capacitance, and radio interference receiver connects interference current coupling circuit.

5. based on a measuring method for the measuring system such as according to any one of claim 1-4, it is characterized in that: comprise the following steps:

(1) connecting test system and power transmission line loop;

(2) progressively raise the voltage be applied on wire, and continue to boost to strong degree of discharge, progressively reduce voltage afterwards, to initial voltage level, record corresponding photon count rate respectively for each steady point of discharge;

(3) according to the pressuring method of step (2), to every root sample repeatedly, the mean value of the photon count rate of each corona point is as the final value of the final photon count rate of each corona point;

(4) according to the pressuring method of step (2), setpoint frequency component in ground unrest acoustic pressure before the bloom of record wire, after wire bloom, under each voltage, the mxm. of difference recording noise acoustic pressure setpoint frequency component and minimum, finally obtain the audible noise mean value that wire samples corona discharge produces, the present invention's corona audible noise setpoint frequency component distinguishes ground unrest;

(5) according to the pressuring method of step (2), the radio interference level of radio interference under contrast frequency before and after bloom under each electric pressure is measured;

(6) change the swoon acoustic pressure of audible noise setpoint frequency component of the tracerse point recorded, screening valid data, calculate radio interference level in corona cage.

6. measuring method as claimed in claim 5, it is characterized in that: in described step (6), the concrete grammar that the acoustic pressure of swooning audible noise setpoint frequency component to the tracerse point recorded is changed is: the acoustic pressure of conductor corona audible noise setpoint frequency component is converted to the decibel value with 20uPa into benchmark, and its conversion formula is: wherein P is the acoustic pressure (unit is Pa) of conductor corona audible noise setpoint frequency component, P _dBfor the wire audible noise setpoint frequency component represented with decibel.

7. measuring method as claimed in claim 5, it is characterized in that: in described step (6), the concrete grammar of screening valid data is: for the radio interference value recorded, according to regulation in GB/T 7349-2002 " high voltage overhead power transmission line, transformer station's radio interference method ", electromagnetic environment field intensity at least should than from the low 6dB of the radio interference field intensity of measurand, first measurement data is screened according to the method, draw valid data, and finally show that in corona cage, radio interference level Ψ can be expressed as:

$\mathrm{\Ψ}=U_{\mathrm{EMI}}-20\lg (Z_{\mathrm{eq}}\·\sqrt{l}\·K)+20\lg \left(\frac{2\mathrm{\π}{\mathrm{\ϵ}}_0}{C_0}\right)---\mathrm{dB}$

In formula, the unit of Ψ becomes dB, U _eMIfor the radio interference voltage measured, Z _eqfor the equivalent resistance of measuring circuit under contrast frequency, l is corona cage length, and K is measuring circuit correction factor, C ₀unit length ground capacitance, ε ₀for permittivity of vacuum.