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Problems To Be Considered In OPGW Design

BY Hunan GL Technology Co.,Ltd.

POST ON:2021-07-13

VIEWS 461 Times


OPGW optical cable lines need to bear various load stretches before and after erection, and they need to face severe natural environments such as high temperature in summer, lightning strikes, and ice and snow in winter, and they also need to face the constant induced currents and short-circuit currents caused by the power phase lines. The harsh operating environment where the temperature rises due to thermal effects, therefore, it is very important to choose the ideal OPGW optical cable. Typical Design For OPGW

 

(1) Selection of raw and auxiliary materials: select world-famous products such as main optical fiber, water-blocking fiber paste, stainless steel strip, aluminum clad steel wire (AS), aluminum alloy wire (AA), etc., to ensure the best Quality indicators.

(2) Mechanical characteristics of OPGW optical cable: The stranded wire outside the core of OPGW optical cable is mainly composed of AA wire (aluminum alloy wire) and AS wire (aluminum clad steel wire) to ensure high strength, high conductivity, and anti-corrosion performance. Excellent, the new generation of composite stainless steel tube OPGW optical cable products are unique among similar products, and meet the urgent needs of my country's 500KV, 220KV and other different voltage levels of line optical fiber communication construction. By adjusting the aluminum/steel ratio and wire specifications, there are more than 100 OPGW cable structures for users to choose.

For loose tube stranded and central tube OPGW optical cable products, the outer diameter of the optical cable is the same in the technical parameters. Due to the different number of AS lines and AA lines, the mechanical and electrical properties of OPGW optical cables are also different. In order to match the sag stress of the OPGW with the ground on the other side, it is required that their mechanical properties, including tensile strength (RTS), elastic modulus, linear expansion coefficient, weight, and outer diameter, should be as close as possible.

(3) Maximum working stress (MAT): When OPGW optical cable is used as the ground wire of the power transmission line, the selection of the maximum working stress is similar to the general ground wire, which is suitable for the adjustment of sag stress in different occasions, and satisfies the center guide and ground wire of the pitch Between distance requirements. Under this premise, the tension should be relaxed as much as possible to ensure that the optical fiber is not stressed under the load.

(4) Average daily operating stress (EDS): The determination of this value directly affects the long-term safe operation of the optical cable. After adopting anti-vibration measures in accordance with the line design specification, the average daily operating stress of the conductor is 15-25% RTS, and it is usually recommended to take The value is 18%.

(5) Short-circuit current capacity (I2t): The short-circuit current capacity of the OPGW cable is related to the current (I) flowing through the OPGW cable when a single-phase ground fault occurs in the system, the protection action time (t), the initial temperature and the maximum allowable temperature. This value is closely related to the OPGW structure cost, and the most scientific and economical shunt index after shunting the optical fiber and 2 ground wires should be considered.

(6) Control of the excess length of the optical fiber in the OPGW optical cable: usually the stranded OPGW obtains the secondary excess length of the optical fiber by twisting the excess length of the optical fiber in the stainless steel tube and twisting the cable to ensure that the optical fiber is not affected by the OPGW cable under the maximum working stress. Strength; the best index to control the excess length of the OPGW optical cable, and to optimize the design through stress-strain tests in combination with operating conditions.

fittings-for-opgw-cables-500x500

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