Carrying capacity evaluation method of overhead transmission line

Abstract

Disclosed in the invention is a carrying capacity evaluation method of an overhead transmission line. A tilt angle sensor is installed at a tower; a lead temperature is calculated based on a lead suspension tilt angle and a wind deflection angle, thereby calculating a lead temperature; a temperature sensor is used for measurement an environmental temperature and a sunlight intensity; current sensors installed at the line are used for measuring real-time loads of the lead; and a heat transmission coefficient is used for representing a combined influence on the lead by microclimate conditions like a wind sped and a wind direction and the like. And then according to the lead temperature model, a real-time maximum carrying capacity of the lead is calculated and evaluated. With the method, an error caused by using the existing lead temperature measurement method can be reduced; the equipment installation time is shortened; the data analysis complexity is reduced; a problem of inaccurate wind speed and wind direction measurement is solved; and reliability of lead carrying capacity calculation is enhanced.

Description

technical field [0001] The invention relates to a method for evaluating the carrying capacity of an overhead power transmission line. Background technique [0002] With the rapid growth of my country's economy, the demand for electricity has risen rapidly. Since the 1970s, my country has gradually entered a situation of power shortage. At the same time, the construction of the transmission network is constrained by factors such as long construction period, huge investment in the first phase, difficulty in land acquisition, and environmental protection issues. Especially around large and medium-sized cities where land is scarce, it is extremely difficult to build new transmission lines. In this context, improving the transmission capacity of the existing power grid has become one of the urgent problems to be solved. [0003] For existing lines, under the premise of not changing the existing network structure and ensuring the safe and reliable operation of the power grid, the...

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Problems solved by technology

[0004] In the existing evaluation system for current carrying capacity of transmission lines, there are generally several measurement methods for the conductor temperature: directly measure the conductor temperature through a sensor, because the conductor is generally very long and the meteorological conditions are not completely consistent, so the temperature at a certain point is measured It is difficult to represent the average temperature of the wire, and there are some errors between the surface temperature of the wire measured by the sensor and the internal temperature; the wire tension is measured by the tension sensor, and the wire temperature is calculated using the wire tension temperature fitting curve. This method can obtain the wire temperature more accurately. Uniform temperature, but installing a tensiometer on the primary side requires a long-term power outage, which will have a certain impact on the operation of the power system; measure the sag of the wire through the image sensor, and use the sag temperature curve to obtain the temperature of the wire. This method only needs to be installed under the wire Several cameras, but the amount of calculation is large and there are certain errors in image processing

For the calculation model of conductor ampacity, the existing evaluation systems mostly use climate models, but the selection of climate conditions is relatively general, and there is a certain deviation from the microclimate conditions in which the conductors are located, and the wind speed and direction of the required calculation parameters generally vary greatly, which is very difficult. Difficult to measure accurately

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