Fuzzy-logic-based ice-covered power transmission line state estimation method

Abstract

The invention discloses a fuzzy-logic-based ice-covered power transmission line state estimation method, which comprises the following steps of: 1, determining and calculating a characteristic quantity of a specific estimated content in two aspects of the mechanical performance and the electric external insulation performance of a lead wire, a ground wire and a tower which serve as objects according to a monitoring parameter; 2, determining a fuzzy logic inference system and an input characteristic quantity and an output quantity thereof, and designing a membership function; 3, building the fuzzy logic inference system, designing a fuzzy rule, and inferring state fuzzy results of the mechanical performance and the electric performance; and 4, defuzzifying the fuzzy results obtained in the step 3 by a centroid anti-fuzzification method, and outputting a fuzzy subset with the maximum membership according to a maximum membership principle to obtain a state estimated result. The method has the advantages of comprehensive estimated content, scientific calculation mode, high accuracy and effectively prevented faults on a power transmission line.

Description

technical field [0001] The invention relates to the technical field of on-line monitoring of icing on overhead transmission lines in the field of electric power, in particular to a state evaluation method for icing transmission lines based on fuzzy logic. Background technique [0002] my country is one of the countries in the world where transmission lines are seriously covered with ice. Severe ice and snow accumulation will lead to a sharp decline in the mechanical and electrical performance of transmission lines, causing accidents such as insulator flashover, line tripping, line disconnection, tower collapse, conductor galloping, and communication interruption. At the beginning of 2008, some provinces in southern my country suffered from the most serious freezing rain and snow disasters in the past 80 years. Ice flashes occurred frequently, and accidents such as line tripping, disconnection and tower collapse were common, which threatened the safe and stable operation of t...

AI Technical Summary

Problems solved by technology

[0004] At present, the existing early warning methods for iced transmission lines carry out early warning from the perspective of line damage, which mainly has the following deficiencies: 1. Only care about the damage of wires. The ground wire and its support have been damaged before the wire is damaged; 2. The horizontal load overload situation is not considered, and the combined effect of loads in several directions is not considered. When the wire is covered with snow with low density, although its equivalent icing The thickness does not reach the design thickness, but its actual thickness far exceeds the design thickness. Under a certain wind speed, the horizontal load is likely to be overloaded; 3. The calculation of overload is not reasonable based on the equivalent ice thickness, which is generally obtained from the state equation of the transmission line Equivalent icing thickness, and then calculate the wire load, and the premise of the state equation is that the line load is evenly distributed. It is not suitable to use the state equation under the situation of uneven icing of the wire formed by the large height difference or large gap difference. Therefore, there is a large error in the calculated value of the ice coating thickness, and the early warning results are quite different from the actual situation; 4. The calculation of the unbalanced tension of the conductor is also based on the calculation of the equivalent ice coating thickness, so the results are also quite different from the actual situation; 5. Only The early warning method of overloading cannot give a comprehensive early warning. Considering that it takes a certain amount of time to take protective measures in actual operation, the early warning information can be issued before the overload to effectively warn of line faults; 6. Only mechanical load evaluation, no electrical performance evaluation, actual insulator ice flash The network is also a major and frequent icing line fault; 7. The evaluation or early warning method is a threshold alarm, which will lead to misjudgment due to the result error caused by the fixed threshold

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