CAJ | 학술논문

直流输电入地电流在交流系统内分布,对变压器和电网造成不良影响。为探讨多层水平土壤情况下直流分布的规律,建立了直流分布的完整计算模型,通过数值计算分析了直流极的简化处理方法案和4层水平土壤对直流分布的影响。计算结果表明：在变电站距离大于10倍直流极尺寸的情况下可以用点电流源代替具体的直流极;场参数的求解是本模型关键,直流模型的场参数实质就是互阻,大型交流电网直流分布不能忽略变电站间互阻的影响;变电站接地电阻和地电位分布均受到大地参数作用呈现一致变化,但受影响程度不同,两者对交流电网总体直流分布的作用相反,造成直流分布呈现非线性变化;大地参数变化至一定程度时不会明显直流分布改变。
직류수전입지전류재교류계통내분포,대변압기화전망조성불량영향。위탐토다층수평토양정황하직류분포적규률,건립료직류분포적완정계산모형,통과수치계산분석료직류겁적간화처리방법안화4층수평토양대직류분포적영향。계산결과표명：재변전참거리대우10배직류겁척촌적정황하가이용점전류원대체구체적직류겁;장삼수적구해시본모형관건,직류모형적장삼수실질취시호조,대형교류전망직류분포불능홀략변전참간호조적영향;변전참접지전조화지전위분포균수도대지삼수작용정현일치변화,단수영향정도불동,량자대교류전망총체직류분포적작용상반,조성직류분포정현비선성변화;대지삼수변화지일정정도시불회명현직류분포개변。
DC distribution in AC grid is caused by earth-return current of HVDC transmission.Adverse effect of transformer and AC grid is led by DC distribution.We established a complete model to analyze the laws of DC distribution under horizontal multi-layer soil,and used numerical methods to simplify the calculation of earth surface potential induced by DC electrode and to evaluate the DC distribution under 4-layer horizontal soil.The results reveal that,if any substation is away from 10 times as the DC electrode＇s dimension,the point source can be used as the specific DC electrode to obtain earth surface potential.Field parameter is the key point of the model while mutual resistance is the essence of field parameter.As to a large-scale power grid,mutual resistance can not be neglected.Soil parameters have the accordant influence on grounding resistance and ESP.But the influential degree is different.As grounding resistance and ESP has the adverse effect,DC distribution is nonlinear with grounding resistance and ESP.When soil parameters change to some extent,DC distribution is saturated.