Emergency Overload Control Strategy Of Wind Power Sending Transmission Channel Based On The Dynamic Overload Capability Of Power Eqiupment

With the rapid development of social demand for the electricity and supply capacity of wind power,the shortage of transmission and transformation capacity of the wind power sending transmission channel is increasingly prominent.It is necessary to study and excavate the safe overload capacity of power transmission and transformation equipment,which is of great significance for mitigating the contradiction of wind power consumption,for ensuring the safe and reliable operation of the sending end power network,and for improving the economic benefit of power companies.Therefore,this paper intensely studied the dynamic evaluation method of the safe overload capacity of power transmission and transformation equipment,established evaluation indexes to quantify the risk of equipment overload operation from multiple perspectives,and proposed an emergency overload control strategy of wind power sending transmission channel considering the dynamic overload capability of power equipment,to achieve the coordinated control of equipment operation safety and sending end power network safety.The main work of the thesis is as follows:a)Power transmission and transformation equipment are designed with specific emergency overload capacity,but the research and utilization of short-term overload tolerance characteristics of equipment are not detailed enough in emergency scenarios.To address this problem,firstly,this paper systematically analyzed the long-time and short-time overload regions of power transmission and transformation equipment,with the transition boundary and corresponding characterization parameters of the overload region.Secondly,the dynamic ampacity calculation method of transmission line has been improved by the meteorological numerical prediction grid,and the dynamic dynamic ampacity calculation method of transformer was studied and analyzed from the perspectives of voltage regulation and temperature limitation,the expressions of equipment overload current and allowable overload time under specific operating conditions were also derived.Finally,examples were constructed to illustrate the calculation methods of power equipment dynamic ampacity.Besides,the influence of meteorological environment factors on the short-time overload capacity of the transmission line and transformer were analyzed.The above researches provided a theoretical basis for the application of short-time overload capacity of power transmission and transformation equipment in emergency scenarios.b)Quantifying the risk of overload operation of power transmission and transformation equipment is the basis for achieving emergency overload control of wind power sending transmission channel.The existing quantification method of overload operation risk of equipment needs to be further improved.Aiming at this problem,this paper uniformly defined the indicators that reflect the overload operation risk of transmission lines and transformers considering the electrothermal safety of power equipment,and proposed real-time risk assessment method and probabilistic risk assessment method to quantify the overload operation risk of power equipment.Then the effectiveness of proposed risk assessment methods were verified by case study,and the advantages and disadvantages of the proposed methods are compared.The proposed risk assessment methods can adequately reflect the operation condition of power equipment and provided a quantitative basis for overload operation risk of power transmission and transformation equipment.c)The existing emergency control strategies to deal with the short-term overload of wind power sending transmission channel do not make full use of the dynamic overload capability of power equipment,which have abundant safety but insufficient economy,so the effects of control strategies are not optimal.To solve this problem,this paper proposed an emergency overload control strategy for wind power sending transmission channels based on the overload risk of power equipment.Firstly,through the joint analysis of operating temperature and failure probability of transmission line and transformer,the risk model of life loss and failure outage of power equipment was established during the short-time overload operation.Afterward,through the analysis of overload cost-economic benefit during the short-term overload period,this paper determined the emergency control strategy with the greatest overload economic benefit,which has considered the economy of overload process under the premise of ensuring the safety of overload process.Finally,the feasibility and effectiveness of the proposed strategy were validated by multiscene cases.The coupling relationship between the service time of power equipment as well as the time to cut off wind turbines and the optimal overload strategy was analyzed in detail.The proposed control strategy takes into account the security and economy of power equipment in overload operation,which can better adapt to the overload condition of equipment in an emergency scenario.