基于雷电耐受能力的配电变压器选型策略

Distribution Transformer Selection Strategy Based on Lightning Tolerance Ability

配电变压器的绝缘配置水平低于配电线路,在遭受雷电侵害时极易造成绝缘击穿事故,在设备选型时通常仅从容量需求角度出发,并未考虑型式差异的影响。基于不同接线组别与容量的配电变压器结构参数,采用ATP-EMTP(electromagnetic transients program,version alternative transients program)软件建立了相应的雷击宽频等效模型,分析型式差异对其雷电耐受能力的影响,研究基于雷电耐受能力的配电变压器选型策略。结果表明:型式和容量差异对配电变压器雷电耐受能力具有一定影响,小容量配电变压器雷击过电压幅值相对较高,接线组别为Dyn-11型的配电变压器雷电耐受能力总体优于Yyn-0型。因此,在设备选型时应统筹考虑。

The accidents of insulation breakdown can be easily happened when suffered by lightning if the insulation level of distribution transformer is lower than that of distribution lines.However,the distribution transformers selection is generally based on the capacity requirements without considering the difference of transformers’types.The equivalent model of lightning broadband was established by electromagnetic transients program,version alternative transients program(ATP-EMTP),considering the different wiring groups and capacities of distribution transformers.The impact of the types of distribution transformers on its lightning tolerance level was analyzed.The type selection strategies based on the lightning tolerance level was proposed.The results show that the impact of the difference of types and capacities on the lightning tolerance of distribution transformers is remarkable.The lightning overvoltage magnitude of small capacity distribution transformers is relatively high and the lightning tolerance of distribution transformers with the type of Dyn-11 is better than that of Yyn-0.Hence,the capacities and the type groups should be considered comprehensively when selecting distribution transformers.