Research On Non-stop Power Supply Of 66kV System In Harbin Power Grid

With the continuous improvement of the national economy,people pay special attention to the improvement of the quality of life,especially the quality and continuity of power supply.Some electric loads involving people's livelihood,important production and operation units,and even the government are particularly important.Even the instantaneous power outage may have an inestimable impact on users,and their requirements for reliability of power supply are increasing day by day.Therefore,power supply enterprises attach great importance to the reliability of power supply and power quality,it is urgent to improve the reliability of power supply.Firstly,this paper studies the demand of non-stop power supply for 66 k V power grid in Harbin.By analyzing the scale and installed capacity of Harbin power grid,the balance relationship between power supply and demand is obtained,the factors affecting non-stop power supply are studied,and the solutions are put forward.Subsequently,the connection modes of 66 k V substations in Harbin power grid are classified,and various types of substation connection which can be closed loop operation are discussed and determined.Through the analysis of the available loop closing paths,the technical conditions for non-stop power supply in Harbin power grid are obtained.In order to determine the theoretical basis for the feasibility of non-stop power supply in Harbin power grid,the concepts related to the closed-loop of 66 k V power grid in Harbin and the key factors affecting the success of the closed-loop are analyzed.The rules and regulations for the relevant loop closing operation of power grid enterprises are studied,and the non-stop power supply scheme of 66 k V power grid in Harbin is designed.The calculation method of closing loop current based on mesh equivalent method and superposition principle is established.The closing loop calculation is carried out for three typical closing loop types in Harbin area.The steady state current and transient impulse current of closing loop are checked whether they exceed the rated current of the line,and the closing operation process is refined.Finally,the non-stop power supply scheme is determined.Finally,the paper studies the influence of non-stop power supply scheme on Harbin 66 k V power grid,and verifies the influence of loop closing operation on relay protection of inner-loop lines.Based on the analysis of the reliability index of power supply in Harbin power grid,the non-stop power supply scheme of Harbin66 k V power grid is proposed,which can transfer load by electromagnetic loop closure for 9 66 k V paths in Harbin area.It can reduce the load loss caused by poweroutage and has positive significance for improving the reliability of power supply in Harbin power grid.