基于非接触耦合式潮流控制器的不停电融冰装置拓扑及控制方法研究

Research on Topology and Control Method of Uninterrupted Ice Melting Device Based on Non-contact Coupling Power Flow Controller

现有分裂子导线的交流融冰技术大多将改变负荷电流,影响正常电力输送,或者影响电力线路正常开断,增加线路停电风险。利用分布式潮流控制器的调控原理,将单匝耦合变压器分布式地卡合在分裂子导线上,将被融冰段内的间隔棒进行绝缘改造,使融冰电流只在融冰段内的子导线间进行轮换;在耦合变压器的控制侧采用旁路开关将融冰装置退出,在并联联接电容与电感元件中采用可控开关实现耦合变压器等效阻抗的柔性调控,与单匝耦合变压器共同形成非接触耦合式交流融冰拓扑;为了不改变负荷电流的大小,基于融冰电流与负荷电流的分流比,推导了被融冰段对外等效阻抗不变的各子导线与融冰子单元等效阻抗的数学关系式,提出不影响正常电力传输的、各子导线依次融冰的各融冰子单元协调控制策略。基于某500kV输电线路实例,从理论计算和数字仿真2个方面验证了所提方法的有效性。

Most of the existing AC deicing technology of split sub-conductors will change the load current,affect the normal power transmission or the normal disconnection of power lines,and thus increase the risk of line outage.Based on the control principle of distributed power flow controller,the single-turn coupling transformer is distributedly stuck on the split sub-conductor,and the spacer rod in the ice melting section is insulated to make the ice melting current rotate only between the sub-conductors in the ice melting section.The bypass switch is used in the control side of the coupling transformer to exit the ice melting device,and the controllable switch is used in the parallel connection capacitor and inductance element to realize the flexible regulation of the equivalent impedance of the coupling transformer.The non-contact coupling AC ice melting topology is formed with the single-turn coupling transformer.In order not to change the magnitude of load current,based on the split ratio of de-icing current and load current,the mathematical relationship between the equivalent impedance of each sub-conductor and de-icing sub-unit with constant external equivalent impedance of de-icing section is derived,and the coordinated control strategy of each de-icing sub-unit without affecting the normal power transmission and de-icing of each sub-conductor in turn is proposed.Based on a 500kV transmission line example,the effectiveness of the proposed method is verified from two aspects of theoretical calculation and digital simulation.