为解决复合绝缘子污闪抑制与伞裙结构协同优化中电气性能与经济性难以兼顾的难题,本文提出一种基于人工污秽试验数据的污闪预测与多目标优化方法。首先,通过人工污秽试验获取50组污闪电压,构建融合Tent混沌映射与黄金正弦机制的减法平...为解决复合绝缘子污闪抑制与伞裙结构协同优化中电气性能与经济性难以兼顾的难题,本文提出一种基于人工污秽试验数据的污闪预测与多目标优化方法。首先,通过人工污秽试验获取50组污闪电压,构建融合Tent混沌映射与黄金正弦机制的减法平均优化器(golden sine subtraction average based optimizer,GSABO)以优化BP神经网络预测模型。其次,采用二代非支配排序遗传算法(non-dominated sorting genetic algorithm II,NSGA-Ⅱ)建立以污闪电压最大化和硅橡胶用量最小化为目标的优化模型,引入电压-成本比(voltage-cost ratio,UCR)选取Pareto前沿最优解。最后,利用有限元仿真及预测模型双重验证优化后的复合绝缘子的电场分布特性和污闪电压。研究结果表明:GSABO-BP预测模型污闪电压平均相对误差为2.198%(R2=0.9856),优化后目标绝缘子污闪电压提升9.23%,硅橡胶用量降低17.02%;沿面最大场强由2.31 MV/m降至1.92 MV/m,电场不均匀系数降低14.9%。本研究为复合绝缘子伞裙结构设计提供了理论与应用依据。展开更多
For converter transformer, AC-DC combined electric field can trigger space charge accumulation on oil-impregnated pressboard interface. The accumulation of space charge on oil-pressboard interface can result in electr...For converter transformer, AC-DC combined electric field can trigger space charge accumulation on oil-impregnated pressboard interface. The accumulation of space charge on oil-pressboard interface can result in electric field distortion, trend to trigger surface discharge of barriers. This paper studied the influence of surface charge on flashover voltage of oil-impregnated pressboard under AC-DC combined electric field. The study finds that the flashover voltage of oil-pressboard interface under negative polarity DC superimposed AC electric field is higher than that.of positive DC superimposed AC voltage to form composite electric field. It was found that homopolar surface charge has been accumulated on the interface of oil-pressboard with positive or negative DC voltage through measuring surface potential by the electrostatic capacitive probe. The surface charge produced electric field in the opposite direction, which weakening the synthetic electric field strength. What＇s more, under the same conditions, the negative surface charge density oil-pressboard is much larger than the positive.展开更多
Surface charge accumulation on insulator surface can have great influence on surface flashover performance.An experimental system is established to investigate surface charge accumulation and decay characteristics of ...Surface charge accumulation on insulator surface can have great influence on surface flashover performance.An experimental system is established to investigate surface charge accumulation and decay characteristics of Al2O3-filled epoxy resin insulators in 0.1 MPa SF6 under DC voltages.Surface potential is recorded by a Kelvin vibrating probe connected to an electrostatic voltmeter.By pre-depositing charges on insulator surface,the influence of surface charges on surface flashover performance is studied.The results reveal that surface charge distribution appearance is the combined effect of electrode injection,back discharge and gas ionization.Surface charge distribution has obvious polarity effect.It is concentrated near the HV electrode under positive voltages and dispersed under negative voltages.The difference in positive and negative surface flashover voltage is attributed to the difference in surface charge distribution under DC voltages of different polarities.Surface charge decay contains two stages,which satisfies the law of double exponential function.At first stage,surface charge decays fast,which corresponds to charges escaping from shallower traps.While it decays slowly at the second stage,which corresponds to charge escaping from deeper traps.Surface charge decay process is dominated by surface conductivity mechanism.The pre-deposited charges on insulation surface have great influence on surface flashover performance.The deposited positive charges can increase positive flashover voltage but decrease negative flashover voltage.展开更多
文摘为解决复合绝缘子污闪抑制与伞裙结构协同优化中电气性能与经济性难以兼顾的难题,本文提出一种基于人工污秽试验数据的污闪预测与多目标优化方法。首先,通过人工污秽试验获取50组污闪电压,构建融合Tent混沌映射与黄金正弦机制的减法平均优化器(golden sine subtraction average based optimizer,GSABO)以优化BP神经网络预测模型。其次,采用二代非支配排序遗传算法(non-dominated sorting genetic algorithm II,NSGA-Ⅱ)建立以污闪电压最大化和硅橡胶用量最小化为目标的优化模型,引入电压-成本比(voltage-cost ratio,UCR)选取Pareto前沿最优解。最后,利用有限元仿真及预测模型双重验证优化后的复合绝缘子的电场分布特性和污闪电压。研究结果表明:GSABO-BP预测模型污闪电压平均相对误差为2.198%(R2=0.9856),优化后目标绝缘子污闪电压提升9.23%,硅橡胶用量降低17.02%;沿面最大场强由2.31 MV/m降至1.92 MV/m,电场不均匀系数降低14.9%。本研究为复合绝缘子伞裙结构设计提供了理论与应用依据。
文摘For converter transformer, AC-DC combined electric field can trigger space charge accumulation on oil-impregnated pressboard interface. The accumulation of space charge on oil-pressboard interface can result in electric field distortion, trend to trigger surface discharge of barriers. This paper studied the influence of surface charge on flashover voltage of oil-impregnated pressboard under AC-DC combined electric field. The study finds that the flashover voltage of oil-pressboard interface under negative polarity DC superimposed AC electric field is higher than that.of positive DC superimposed AC voltage to form composite electric field. It was found that homopolar surface charge has been accumulated on the interface of oil-pressboard with positive or negative DC voltage through measuring surface potential by the electrostatic capacitive probe. The surface charge produced electric field in the opposite direction, which weakening the synthetic electric field strength. What＇s more, under the same conditions, the negative surface charge density oil-pressboard is much larger than the positive.
文摘Surface charge accumulation on insulator surface can have great influence on surface flashover performance.An experimental system is established to investigate surface charge accumulation and decay characteristics of Al2O3-filled epoxy resin insulators in 0.1 MPa SF6 under DC voltages.Surface potential is recorded by a Kelvin vibrating probe connected to an electrostatic voltmeter.By pre-depositing charges on insulator surface,the influence of surface charges on surface flashover performance is studied.The results reveal that surface charge distribution appearance is the combined effect of electrode injection,back discharge and gas ionization.Surface charge distribution has obvious polarity effect.It is concentrated near the HV electrode under positive voltages and dispersed under negative voltages.The difference in positive and negative surface flashover voltage is attributed to the difference in surface charge distribution under DC voltages of different polarities.Surface charge decay contains two stages,which satisfies the law of double exponential function.At first stage,surface charge decays fast,which corresponds to charges escaping from shallower traps.While it decays slowly at the second stage,which corresponds to charge escaping from deeper traps.Surface charge decay process is dominated by surface conductivity mechanism.The pre-deposited charges on insulation surface have great influence on surface flashover performance.The deposited positive charges can increase positive flashover voltage but decrease negative flashover voltage.
