Search

In the ground wire-clamp system, aluminum armor tape (AAT) or armor rod (AR) is commonly adopted to avoid the wear damage of ground wire. While under the short-circuit current, damage or even breakage of ground wire in suspension clamp due to overheat may occur. However, there still lacks attention on the investigation about this type of damage. In this paper, a finite element (FE) modeling method of the ground wire-clamp system, which was applicable to two cases with AAT and AR, was proposed to discuss the transient thermal and mechanical behaviors. In the modeling of contact points, an improved contact bridge model considering the contact shape characteristics was proposed. The transient temperature rise experiments for ground wire-clamp systems with AAT and AR were carried out to verify the accuracy of models. The results shows that the improved contact bridge model is conducive to obtaining the accurate calculation results. For the analysis of this type of damage, the generated thermal stress cannot be ignored. In engineering, the ground wire twinned by AAT is at risk of overheat or even breakage under the short-circuit current, while using AR can prevent the ground wire in the suspension clamp from damage of overheat.

The traditional dynamic capacity-increasing technology of overhead conductors needs to monitor the operation state of conductors (temperature, sag, etc.), and the relevant sensors are usually installed directly on the surface of conductors. The installation cost is high, and the operating maintenance is complicated. In this paper, a non-contact dynamic capacity-increasing method for overhead conductors based on CT is proposed. Firstly, the theory of the non-contact dynamic capacity-increasing method for conductors is introduced, and a cooling testing device is designed according to the theory. Then, the cooling index is defined to represent the cooling capacity of the object, and the corresponding cooling indexes for the conductors and the CT are calculated based on the steady-state thermal balance equation. By establishing a cooling correlation model for the conductors and the CT, the calculation for the dynamic ampacity of the conductors can be obtained. Finally, the cooling conditions of cooling testing device at different ambient temperatures and wind speeds are calculated through the finite element simulation method. Combined with the dynamic capacityincreasing method proposed in this paper, the corresponding ampacity value are obtained, and the effect of capacity increase is analyzed. The results show that the non-contact dynamic capacity-increasing method based on the CT has obvious effect in capacity-increasing compared with the static ampacity.