Overhead transmission line dynamic current-carrying capacity monitoring method and its device

Abstract

The invention relates to a method and device for monitoring dynamic current capacity of aerial power line, comprising: 1) equipping the neutral wire having the same material and size with the live wire parallel with the live aerial power line, wherein, the temperature of the neutral wire is set to be T, and the actual temperature of the live wire of the actual line is set to be T; 2) the computing formula of the line dynamic current capacity is given; 3) calculating the equivalent wind-speed coefficient M; 4) calculating the line dynamic current capacity Imax, i.e. the value of the line dynamic current capacity. The invention eliminates the meteorology parameter variation thereby simplifying calculation and having stable result fluctuation and correct result by using special temperature measuring device to measure the temperatures of the live actual wire and the neutral wire in real time, and proposing a new algorithm which uses actual wire temperature and the temperature of wire of the same type to substitute the wind-speed and wind-direction in convection loss in the dynamic current capacity calculation.

Description

technical field [0001] The invention relates to the field of monitoring the dynamic ampacity of transmission lines, in particular to a method and device for monitoring the dynamic ampacity of overhead transmission lines, and is particularly suitable for the field of dynamic ampacity monitoring of operational transmission lines under the condition of meteorological parameter changes. Background technique [0002] The ampacity (thermal rating) of overhead transmission lines is the main parameter of line design and operation. The calculation method of ampacity is mainly adopted in the world: International Institute of Electrical and Electronics Engineers (IEEE) standard Std.738-2006 "bare overhead conductor current - IEEE Standard for Temperature Calculation" [1] , International Electrotechnical Commission (IEC) Standard IEC1597-1995 "Calculation Method for Overhead Power Conductor - Bare Stranded Wire" [2] and CIGRE 22.12 Working Group Report "Thermal Characteristics of Overh...

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Problems solved by technology

[0017] 2) Natural convection heat loss:

[0020] 3) Radiation heat loss:

[0027] The calculation methods of ampacity introduced above are derived under the assumption that the surrounding meteorological parameters are constant. Although these methods are also applicable to the calculation of dynamic ampacity when real-time meteorological data is used, they are not stable when meteorological parameters change, especially wind speed and wind direction. In the case of large changes (and it is difficult to accurately measure the wind speed and wind direction at this time), the dynamic ampacity calculated by these methods has large fluctuations and large errors, which cannot be applied in real time

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