变压器式可控电抗器限流电感计算

Calculation of Current-Limiting Inductance of Controllable Reactor of Transformer Type

变压器式可控电抗器(CRT)以固定单支路调节模式运行时具有优越的谐波性能,而为其各限流电感匹配合适的参数则是实现固定单支路调节模式的关键所在。基于CRT的自、互电感电路方程,导出CRT工作绕组瞬时电流及其基波分量有效值的计算公式,进而引入调节过程及容量区间的概念。根据CRT固定单支路调节模式的切换流程,一方面基于CRT输出容量连续且各容量区间重叠最小的原则,建立了求解各限流电感的优化模型;另一方面按照已有文献认为各控制绕组电流互不影响的理想情况建立了求解限流电感的非线性方程组。最后设计算例,借助Matlab优化工具箱进行求解,结果表明按理想情况求出的限流电感会造成大范围容量断续,是不可取的,而采用所提出的优化方法得出的参数则能有效地实现CRT的固定单支路调节模式。

The harmonic characteristics are quite superior when CRT(controllable reactor oftransformer type)operates in fixed-single-branch regulating mode.Matching an appropriate parameterfor each current-limiting inductance is the key to implement the fixed-single-branch regulating mode.Based on the circuit equations expressed by the self and mutual inductances of CRT,the instantaneousexpression of work winding current and the formula for calculating its fundamental RMS were derived.And then the definitions of regulating process and capacitance range were proposed.According to theregulating process of fixed-single-branch mode,an optimization model for calculating thecurrent-limiting inductances was established following the principle of keeping continuous outputpower and minimum overlap among all the capacitance ranges,while the nonlinear equations forcalculating the current-limiting inductances were also established on the basis of the ideal situation inliteratures that the currents in different control windings are independently each other.Finally,anexample was designed and solved by Matlab optimization tool.The results show that the parametersobtained in the ideal situation lead to a wide range of discontinuity to the output power,which areinadvisable;while the ones calculated by the proposed optimization model can implement thefixed-single-branch mode efficiently.