IEC 62428 pdf download

IEC 62428 pdf download Electric power engineering – Modal components in three-phase a.c. systems – Quantities and transformations
1 Scope
This International Standard deals with transformations from original quantities into modal quantities for the widely used three-phase a.c. systems in the field of electric power engineering. The examination of operating conditions and transient phenomena in three-phase a.c. systems becomes more difficult by the resistive, inductive or capacitive coupling between the phase elements and line conductors.
Calculation and description of these phenomena in three-phase a.c. systems are easier if the quantities of the coupled phase elements and line conductors are transformed into modal quantities. The calculation becomes very easy if the transformation leads to decoupled modal systems. The original impedance and admittance matrices are transformed to modal impedance and admittance matrices. In the case of decoupling of the modal quantities, the modal impedance and admittance matrices become diagonal matrices.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60050-1 41 , International Electrotechnical Vocabulary (IEV) – Part 141: Polyphase systems and circuits
3 Terms, definitions, quantities and concepts
3.1 General
Quantities in this standard are usually time-dependent. These quantities are for instance electric currents, voltages, linked fluxes, current linkages, electric and magnetic fluxes.
For quantities the general letter symbol g in case of real instantaneous values, g in case of complex instantaneous values and G in case of phasors (complex r.m.s. values) are used.
NOTE Complex quantities in this standard are underlined. Conjugated complex quantities are indicated by an additional asterisk (*). Matrices and column vectors are printed in bold face type, italic.
3.2 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-1 41 and the following apply.
3.2.1
original quantities
quantities g or G of a three-phase a.c. system
NOTE Subscripts 1 , 2, 3 are generally used in this standard; additional letters may be put, for instance L1 , L2, L3 as established in IEC 60909, IEC 60865 and IEC 61 660.
4 Modal transformation
4.1 General
The original quantities 3 2 1 , , g g g and the modal components M3 M2 M1 , , g g g are related to each other by the following transformation equations:
or in a shortened form: M g T g = (2) The coefficients ik t of the transformation matrix T can all be real or some of them can be complex. It is necessary that the transformation matrix T is non-singular, so that the inverse relationship of Equation (2) is valid.