부산대학교 도서관

覆冰严重会影响电网安全稳定运行,输配电装备的覆冰监测是电网冰灾防御的前提.为此,基于冰层的电容效应提出一种旋转圆柱三电极阵列覆冰测量方法.首先,推导电容值与覆冰厚度计算公式,从理论上说明该方法的可行性;其次,建立圆柱三电极阵列有限元模型并对其结构参数进行有限元数值计算;再次,以信号强度、灵敏度与穿透深度为评价指标对圆柱三电极阵列选取合适参数;最后,在野外自然环境下对旋转圆柱三电极阵列覆冰测量装置进行试验.仿真和试验结果表明,在穿透深度以内,旋转圆柱三电极阵列能够较为准确地测量覆冰厚度、分辨覆冰类型.在雨凇、混合凇覆冰条件下,覆冰电容值平均误差最大为 4.83%,能够满足覆冰厚度的测量要求.该文为输配电装备覆冰监测提供了一种新型装置与测量方法,未来有望应用于架空线路覆冰在线监测.
Icing seriously affects the safety and stability of power system.Icing monitoring of power transmission and distribution equipment is a prerequisite for preventing icing disaster.The ice measurement method based on capacitive effect has the advantages of simple measurement,high sensitivity and easily integrated.However,under the condition of wing-shaped icing and crescent-shaped icing,the existing methods are limited by the single electrode shape,and it is difficult to measure the thickness of icing accurately. To solve the problem,this paper proposes a rotating cylindrical three-electrode array icing measurement method based on the capacitance effect of icing.The cylindrical three-electrode array is driven by a motor to rotate at low speed which can make a uniform cylindrical icing attached to its surface.This method can get rid of the limitations of existing methods and make the measurement more accurate. Firstly,the rotating cylindrical three-electrode array structure was designed based on the measurement principle.The feasibility of the proposed method was evaluated with derivating the numerical relationship between the capacitance value and the thickness of icing based onangle-preserving transformation method.The number of electrode units,electrode height,insulating ring height,electrode thickness,electrode outer diameter,and relative dielectric constant were found to affect the capacitance measurement performance by the formula.Secondly,a three-dimensional finite element model of the cylindrical three-electrode array was established and its structural parameters were numerically calculated by finite elements.The simulation results show that the increase of electrode coverage rate,electrode outer diameterand three-electrode array will increase the signal strength and sensitivity of the cylindrical three-electrode array.The electrode thickness has little effect on its icing capacitance measurement performance.Finally,optimised parameters for the design of the cylindrical three-electrode array were obtained with considering signal strength(S/N ratio),sensitivity and penetration depth.A natural icing test of the rotating cylindrical three electrode array icing measuring device was carried out in the field. The results show that when the outer diameter of electrodes is the same,the value of icing capacitance in glaze is significantly higher than that in hard rime.When the type of icing and the thickness of icing are the same,the larger the outer diameter,the larger the measured capacitance value.Under the conditions of glaze and hard rime,the penetration depth is approximate 12 mm and the rotating cylindrical three-electrode array can measure the thickness of ice and distinguish the type of icing within its penetration depth.The maximum average error of icing capacitance value is 4.83%,which can fulfill the measurement requirement on the thickness of icing. The rotating cylindrical three-electrode array icing monitoring device fulfills the automatic acquisition of icing capacitance values which meets the requirements for accurate online measurement of icing thickness.This paper provides a new device and method for icing monitoring of transmission and distribution equipment,and demonstrates its feasibility.The next step will be to conduct research on the engineering application of this method,especially the practical application of overhead transmission line equivalent icing thickness monitoring.