RU2013121709A - METHOD FOR DETECTING POWER CABLE DAMAGE - Google Patents

Abstract

A method for determining damage to a power supply cable, including connecting an AC source to a power supply cable, measuring a magnetic field, characterized in that the measurements are carried out on the earth's surface and at a height and at the beginning and end of the cable section allocated for measurement with a length L, the occurrence depth is calculated cable h and h at the beginning and end of the cable section, determine the conductivity of the cable section under study according to the formula: cable section, A / m; and - magnetic field strength at a height above the ground at the beginning and end of the cable section under study, A / m; h and h - cable depth at the beginning and end of the cable section under study, m; L - length of the studied section of the power supply cable, m; Z - longitudinal resistance of the cable, Ohm / m; the obtained value of the insulation conductivity is compared with the conductivity of the undamaged cable Y, the ratio Y> Y indicates the presence of damage to the power cable in the studied section, then the section is divided into two The parts (in the particular case, equal) of lengths L and L, repeat the measurements, determine the conductivity of the first Y and second Y parts of the section, compare the obtained values with the conductivity of the undamaged cable Y, if Y> Y, then the damage is in the first part of the cable section, if Y> Y- in the second, then the process is repeated until the specified (required) length of the cable section on which the damage is located is determined.

Claims (1)

A method for determining damage to a power cable, including connecting an AC source to a power cable, measuring a magnetic field, characterized in that the measurements are carried out on the surface of the earth and at a height and at the beginning and end of the cable section allocated for measurement with a length L, the occurrence depth is calculated cable h ₁ and h ₂ at the beginning and end of the cable section, determine the conductivity of the studied cable section by the formula: $$Y=\frac{{\left(\ln \frac{H_{\mathrm{one}}{h}_{\mathrm{one}}}{H_2{h}_2}\right)}^2}{L^{2}Z},$$

where H ₁ and H ₂ - magnetic field strength on the earth's surface at the beginning and end of the studied section of the cable, A / m; $$H_{\mathrm{one}}^{\text{'}\text{'}}$$

and $$H_2^{\text{'}\text{'}}$$

- magnetic field strength at a height above the surface of the earth at the beginning and end of the studied cable section, A / m; h ₁ and h ₂ - the depth of the cable at the beginning and end of the studied section of the cable, m; $$h_{\mathrm{one}}=\frac{a}{\frac{H_{\mathrm{one}}}{H_{\mathrm{one}}^{\text{'}\text{'}}}-\mathrm{one}}{\text{and H}}_{\text{2}}=\frac{a}{\frac{H_2}{H_2^{\text{'}\text{'}}}-\mathrm{one}},$$

L is the length of the investigated section of the power cable, m; Z is the longitudinal resistance of the cable, Ohm / m; the obtained value of the insulation conductivity is compared with the conductivity of the undamaged cable Y _H , the ratio Y> Y _H indicates the presence of damage to the power supply cable in the studied section, then the section is divided into two parts (in the particular case, equal) with the lengths L ₁ and L ₂ , repeat the measurements, determine conductivity of the first Y ₁ and second Y ₂ parts of the section, compare the obtained values with the conductivity of the undamaged cable Y _H , if Y ₁ > Y _H , then the damage is in the first part of the cable section, if Y ₂ > Y _H - in the second, then repeat the process It takes until the specified (required) length of the cable section on which the damage is located is determined.