变压器降容率及谐波损耗因子F_(HL)与K的比较

Transformer derating and comparison of harmonic loss factor F_(HL) with K-factor

谐波电流引起变压器附加损耗,受绕组或油温限制,变压器需要降容量运行。在介绍了反映谐波涡流损耗的两个常见因子,即K和FHL,以及变压器谐波损耗公式的基础上,本文推导了两因子确定最大允许谐波电流值的不同机理及其相互关系。

The transformer losses will increase when operating under harmonic load conditions. The derating measure is always taken to limit the temperature of windings or top-oil. Based on introduction of two harmonic loss factors, K-factor and FHL, and the equations of the total losses of transformer, this paper reasoned out the difference of the computed maximum permissible rms non-sinusoidal load current of derating using the harmonic loss factor FHL and K-factor. Keeping within the rated power loss limits, maximum permissible rms non-sinusoidal load current using K-factor approach is relatively conservative because derating winding eddy current losses is replaced with pre-derating ones. The harmonic loss factor FHL is a function of the harmonic current distribution and is independent of the relative magnitude. Maximum permissible rms non-sinusoidal load current using FHL approach is relatively economical for taking account of actual operating harmonic current. The relationship of two harmonic loss factors and their application were also discussed in this paper.