ORU-CAD algorithm for computer-aided SLD selection for 35- to 220-kV outdoor switchgears

Using CAD when designing the electrical part of substations does reduce the time spent by the designer to solve routine problems. The paper describes an algorithm for computer-aided selection of single-line diagrams for 35- to 220-kV outdoor switchgears as implemented ORU CAD. The algorithm herein proposed selects switchgear SLD based on the effective codes and design standards. In addition, alternative options are proposed that satisfy some of the conditions for their subsequent comparison by the reliability criteria and the resultant costs. When running SLD selection, the algorithm considers such factors as the voltage class and number of connections, the type of substation, the number of non-redundant connections, and the need for an ice-melting system on power lines. In addition, for dead-end substations it considers the possibility of transmitting a relay protection signal to the power supply switch as well as the presence of dead-end substations on the power transmission line. For pass-through substations, it considers the possible need for frequent power transformer switching. The software described in this paper can be used as an automated workstation for the electrical engineer responsible the electrical part of the substations.