As the capacity and scale of distribution networks continue to expand, and distributed generation technology is increasingly mature, the traditional fault location is no longer applicable to an active distribution network and "two-way" power flow structure. In this paper, a fault location method based on Karrenbauer transform and support vector machine regression (SVR) is proposed. Firstly, according to the influence of Karrenbauer transformation on phase angle difference before and after section fault in a low-voltage active distribution network, the fault regions and types are inferred preliminarily. Then, in the feature extraction stage, combined with the characteristics of distribution network fault mechanism, the fault feature sample set is established by using the phase angle difference of the Karrenbauer current. Finally, the fault category prediction model based on SVR was established to solve the problem of a single-phase mode transformation modulus and the indistinct identification of two-phase short circuits, then more accurate fault segments and categories were obtained. The proposed fault location method is simulated and verified by building a distribution network system model. The results show that compared with other methods in the field of fault detection, the fault location accuracy of the proposed method can reach 98.56%, which can enhance the robustness of rapid fault location.

The article presents a results of study on the impact of replacing CEM I SR3/NA by CEMIII/A LH/HSR/NAon the mechanical properties and durability of pavement concrete with exposed aggregate. Was used granite aggregate and washed sand. Water/cement (w / c) ratio in the tested concretes constituted 0.35 and 0.4 and part of the cement was replaced with a 5% addition of natural pozzolana – zeolite. Compressive strength tests were performed after 3, 7, 28 and 56 days, tests of tensile strength test by splitting method and flexural strength two-point loading tests. The characteristics of the air pores and the rate of water absorption by concrete surface of the samples cut out from the slabs with exposed aggregate were presented. The resistance of the surface to exfoliation after 56 cycles of freezing-thawing in NaCl solution was tested. Based on the results obtained, it was found that when designing the composition of the concrete intended for the upper layer of the pavement, it is necessary to ensure high tensile strength, appropriate in the XF4 environment and with the decrease in the w / c < 0.4, a reduction in capillary porosity of the cement paste is obtained, and the same the durability of concrete is increased due to the improved strength parameters in the contact zone between coarse aggregate grains and cement paste. The research also showed a significant influence of proper cure on the mechanical properties and durability of pavement concrete.