Methodology for assessing the efficiency of UAV application for power line diagnostics

. Unmanned aerial vehicles are expanding technical applications. One of the promising areas is the electric power industry. The article proposes a methodology for assessing the efficiency of UAV use for diagnostics of power lines. The main criteria are the speed of electrical equipment diagnostics and financial costs. An example of realization is given. It is shown that the financial costs are already lower than the standard bypass of the repair team. This is due to the higher speed of diagnostics works


Introduction
The new decade is characterized by the widespread use of unmanned technology.Unmanned aerial vehicles (UAVs) are expanding their influence on the efficiency of various sectors of the economy.The most important area of the economy is the electric power industry.The normal operation of electrical networks is essential for the functioning of industrial and social facilities.Therefore, effective methods of control and maintenance of electric power facilities are necessary [1-12].Currently, much work is devoted to the improvement of UAVs.Approaches to means and methods of surveying objects [1][2][3][4][5][6] are being improved.New technologies and methods of supplying UAVs with electric power to increase reliability and flight duration are being developed [7][8][9][10][11][12] .However, to increase the speed and scale of UAV technology utilization, it is necessary to justify its effectiveness.This paper proposes a methodology for evaluating the effectiveness of UAV application for power line survey.

Materials and methods
To perform power line diagnostics, the important parameters are the financial cost and speed of the work.Financial costs of power line surveys: C1 -personnel costs, RUB.; C2 -maintenance costs, RUB.
CTi -cost of 1 hour of work of personnel with different qualifications, RUB.; T -working time, RUB.
Operating costs for an сar: η -сar fuel consumption, l/100 km; β -fuel cost, RUB/l.Two approaches were compared: a UAV and a repair team.DJI Mavic 3 Т is used as a UAV, the cost of which is 580,000 rubles, characteristics are shown in Table 1.UAZ 3909 is used as a repair team vehicle, the cost of which is 1650000 rubles, characteristics are shown in Table 2.The appearance of the equipment is shown in Figure 1.The salary of the UAV operator is 80000 rubles/month.Salary of the crew driver is 35000 rubles.Salary of the electrician on repair of power lines is 40000 rubles.Salaries are taken from the HeadHunter job search service portal.

Results
Diagnostics of 110 kV overhead line "Lyskovo-Vargany" in Kstovo district of Nizhny Novgorod region with the length of 28.4 km including 21 supports is considered.The results of calculations are given in Table 3. Note: 1RUB=0,01$

Discussion
The calculations have shown that diagnostics of power grid complex using UAVs is economically justified today.The cost of diagnostics of power lines using UAVs is 5.5 times less than the cost of diagnostics performed by a repair team.The reason for lower costs when using UAVs can be understood by analyzing the cost items of both methods of power line diagnostics (Figure 2).The main share of costs for both methods is the wages of maintenance personnel.However, the wage costs of the maintenance personnel are 6.9 times higher for the repair team than for the UAV.This is mainly due to the long time for the repair crew to diagnose transmission lines.The average speed for human inspection is 5 km/h.The average speed for moving the repair crew to the site is 60 km/h.At the same time, the speed of inspection with the use of UAV is 68.4 km/h.Therefore, the number of paid hours for maintenance personnel is less when UAVs diagnose power lines.In addition, the use of UAVs can achieve even greater effect in hard-to-reach places.It should be noted that the cost of electricity for charging the UAV battery in the overall balance is close to zero.However, gasoline costs for the repair team vehicle are 12%.Amortization costs for the equipment are comparable.

Conclusion
Unmanned aerial vehicles are an effective means of diagnostics of high-voltage power lines.The proposed methodology for assessing the efficiency of UAV application in the electric power industry allows estimating the time and financial costs of diagnostics by various methods.An example of realization of the methodology on a real 110kV power line is shown.It is established that diagnostics of power transmission lines using UAVs is more effective both in time and financial costs than diagnostics by a repair team.Based on the obtained data, we can expect the growth of UAV application in the electric power industry.

Fig. 1 .
Fig. 1.Appearance of the equipment used for power line diagnostics.

Table 3 .
Comparison of methods of diagnostics of 110 kV transmission line.