The tree-line contradiction is an important factor affecting the reliability of power supply in township distribution networks. In recent years, strong convective weather has occurred from time to time, and the superposition of the two has posed a great threat to the safe operation of township distribution networks. At the same time, improving the reliability of power supply and meeting the normal production and living needs of residents has become an inevitable requirement for the development of township distribution networks in the new era. Therefore, it is necessary to study the early warning and optimization technology of tree line contradiction risk in township distribution network considering the impact of strong convective weather, so as to help the high-quality development of the power industry and the construction of a new national countryside.
Background:
The township distribution network in mainland China has the characteristics of wide coverage, low degree of automation, and relatively poor safety environment, so it faces many risk factors, resulting in frequent failures. According to statistics, among the many fault records, the grounding fault caused by the contradiction of the tree line accounts for a large proportion.
This is because although the township power supply company will regularly inspect the line, prune the ultra-high and ultra-wide trees in time, but can only ensure the reliable operation of the distribution line under normal weather conditions, once encountering strong wind, heavy rain and other strong convective weather, due to factors such as line dancing, tree swaying and even bending and overturning, the air between the tree lines is very easy to break down, causing grounding faults, and has a huge impact on the power supply of local areas and even the entire distribution line.
Therefore, it is necessary to organize and carry out further line inspection and obstacle removal work before the arrival of strong convective weather, so as to improve the power supply reliability of the distribution network in a targeted manner.
However, the time is tight before the arrival of strong convective weather, and the wreck clearing resources of the township power supply company are limited, and the pre-event obstacle removal process also requires planned power outages, which will also produce power outage losses, so it is necessary to combine the fault probability of each tree line contradiction prone point, weigh the planned power outage loss and the cost of pre-event clearance, as well as the fault loss and post-treatment cost, and make a proper decision on whether to take pre-clearance measures. Mathematically speaking, it is essentially an optimization problem, but this problem has not been studied much yet.
The problem solved by the paper and its significance
1) This paper fully takes into account the regional correlation characteristics of severe convective weather, and establishes an early warning model of tree barrier grounding risk in each region of the township distribution network based on the support vector machine, which can effectively mine the mapping relationship between meteorological information and tree line contradiction, and provide a basis for the precise prevention and control of power outages in the township distribution network under severe convective weather.
2) This paper proposes a tree-line contradiction optimization strategy that takes into account the overall economic investment and power outage loss, which can properly weigh the obstacle clearance cost and power outage loss of each contradiction-prone point, and give the most economical pre-clearance plan, which can effectively guide the obstacle clearance process of township power supply companies before the arrival of strong convective weather.
Dissertation Methods and Innovations
Firstly, considering the regional correlation characteristics of severe convective weather, the meteorological monitoring information of the whole power supply area of the township distribution network was taken as the data to be classified, and the problem of tree barrier grounding was used as the label, and the contradiction mapping model of severe convective weather-tree line in each region of the township distribution network was established based on the support vector machine, so as to realize the zonal early warning of tree barrier grounding risk. Finally, combined with the data of strong convective weather in a certain area of mainland China, the grounding fault record of tree barriers, and the improved IEEE 33-node system and 123-node system are analyzed to verify the effectiveness of the proposed model and method.
Compared with the existing research, the main innovation of this paper is that it fully takes into account the regional correlation characteristics of severe convective weather and the time urgency before its arrival, the limited resource of obstacle removal of township power supply companies and the task volume characteristics of each contradiction-prone point, and forms a set of "zonal early warning-overall trade-off-optimization treatment" mechanism for tree barrier grounding, which can monitor, warn and properly deal with the tree-line contradiction, and effectively improve the risk defense level of township distribution network under strong convective weather.
conclusion
1) Severe convective weather has a certain regional correlation characteristic, and in the process of early warning modeling of tree barrier grounding risk, it is helpful to accurately characterize this characteristic from the perspective of small-scale meteorological monitoring system, which is helpful to improve the accuracy of the model output results.
2) The early warning model of tree barrier grounding risk in the township distribution network established in this paper can effectively explore the mapping relationship between strong convective weather and tree line contradiction, and realize the zonal early warning of tree barrier grounding risk.
3) The tree-line contradiction optimization model of the township distribution network proposed in this paper can properly weigh the cost of obstacle removal and the loss of power outage at each contradiction-prone point, and give the most economical pre-clearance plan, which is not affected by the change of system topology.
Meet the team
The research team is affiliated to the National Key Laboratory of Strong Electromagnetic Technology, and is mainly engaged in the research of new technologies of distribution network and microgrid, intelligent dispatching and automation of power grid, power system protection and control, and modeling and application of compressed air energy storage.
Miao Shihong, Ph.D., Professor, Doctoral Supervisor, Member of Compressed Air Energy Storage Sub-Committee of Energy Storage Standardization Technical Committee of China Energy Research Society, IEEE Transactions on Power Delivery, IET Generation, Transformation & Distribution, Proceedings of the CSEE, Transactions of China Electrotechnical Society, Power System Automation He has been engaged in teaching, research and equipment research and development in power system relay protection and automation, new technology of distribution network and microgrid, compressed air energy storage modeling and application, intelligent dispatching and automation of power system for a long time, and has published more than 130 academic papers (including 84 EI papers and 23 SCI papers). In recent years, he has presided over 2 national key R&D projects, 3 national natural science research foundations, and has also presided over or participated in a number of national 973 program projects, 863 program projects and science and technology projects of the State Grid Corporation headquarters.
The results of this work were published in the 22nd issue of Transactions of China Electrotechnical Society in 2023, and the title of the paper is "Early Warning and Optimization of Treeline Contradiction Risk in Township Distribution Network Considering Severe Convective Weather". This project was supported by the Science and Technology Project of State Grid Henan Electric Power Company.