A Software Framework for Advanced Power System Analysis: Case Studies in Networks, Distributed Generation, and Distributed Computation

Elem ent IConnElem ICktLaws AbstractXfrm AbstractSw itch AbstractCable CableXfrm AbstractSw itch AbstractCable Cable Fangxing Li Chapter 3 –...Composite Cables... 63 • A three-phase cable with concentric neutrals (It has 6 paths, 3 phase paths and 3 neutral returns). • A composite cable consists of multiple sets of three-phase conductors placed in different ducts, with terminals tied together. Although we have simple and complicated configurations of cables, each configuration has many similarities. From the client’s point of view, each cable provides two interfaces IConnElem and ICktLaws, as stated in Chapter 2. Next we discuss the common attributes of cable models. All cables share the following similarities that can be presented in the AbstractCable class. • Each cable impedance can be represented by a 3x3 impedance matrix. For a single-phase conductor, there is only one non-zero entry. For the composite cable, after reduction, as stated in Sections 3.2, its impedance matrix is a full 3x3 matrix. • As a two-port element, each cable has currents, voltages, and power flows at two ports. They are represented with a 3x1 vector as I, V1, V2, S1 and S2, since the three-phase model is considered here. For single-phase cables, the above vector variables contain zero elements. • All components keep track of directly connected components. Each has pointers pointing to its preceding (parent) element, left-most succeeding (child) element, and right sibling element, geographically. This is common to all elements, including any cable classes. Fangxing Li Chapter 3 –...Composite Cables... 64 B) Designing Class Hierarchy Since the three-phase model concerns the phase characteristics of conductors, we can group the types of cables in the following way. • Single-phase cable One-path, single-phase cable Two-path, single-phase cable (with concentric neutral return) • Three-phase cable Three-paths, three phase cable Six-paths, three phase cable (with concentric neutral returns)