Omar Saad

Multiphase Load-Flow Solution for Large-Scale Distribution Systems Using MANA

The unbalanced nature of distribution systems requires a multiphase load-flow solution capable of handling arbitrary network topologies and providing accurate results. The need for detailed analysis of secondary grid systems found in dense urban areas and the modeling of distribution networks including the subtransmission level requires using highly efficient and large-scale system-capable methods. In this paper, three different load-flow solution algorithms are presented using the modified-augmented-nodal-analysis formulation. The load-flow solution algorithms are compared for the IEEE 8500-node distribution test feeder using a proposed regulator tap control strategy.

Synchronous Machine Modeling Precision and Efficiency in Electromagnetic Transients

This paper presents various synchronous machine models implemented in the computation of electromagnetic transients. This paper proposes new models for achieving better computational efficiency while maintaining precision. In addition to simple infinite bus analysis, the machine models are also compared for a more sophisticated and practical case study. Precision analysis includes the surrounding network accuracy constraints.

An Efficient Synchronous Machine Model for Electromagnetic Transients

This paper proposes a new synchronous machine model based on the application of Parks transformation to the discretized equations of the phase-domain model. The proposed approach maintains the precision of the phase-domain model and eliminates its computational inefficiencies through a constant admittance matrix. The model includes magnetic saturation. Precision analysis is performed within the accuracy constraints of the surrounding network.

Computation of power system transients: Modeling portability

This panel paper presents research activities related to modeling portability between electromagnetic transients simulation programs. Although modern computer programs are provided with sophisticated graphical user interfaces, each program has its own modeling interface and model development methods. There are no portability or interoperability standards between applications of the same type. This issue creates significant and time consuming problems for the users since it is often required in the same organization to perform studies using different applications or to receive models available from different manufacturers using different tools. This paper focuses on methods that can be used for developing and establishing modeling portability. Both model data portability and actual model portability are discussed. The topic is also related to user-defined modeling.

An Efficient Voltage-Behind-Reactance Formulation-Based Synchronous Machine Model for Electromagnetic Transients

This paper proposes a new synchronous machine model based on the voltage-behind-reactance (VBR) formulation. The proposed approach maintains the accuracy of the VBR model and eliminates its computational inefficiencies. The new model also includes an iterative solution option for achieving higher accuracy. The proposed model is tested and compared to other modeling approaches using practical power system test cases.

Efficient Computation of Feedback-Based Control System Equations for Electromagnetic Transients

Summary form only given. This paper contributes to the accurate and efficient computation of control system equations in electromagnetic transient (EMT) simulation tools. The proposed approach is based on the formulation of a reduced rank Jacobian matrix in a fully iterative Newton method. In addition, this paper compares accuracy and efficiency for the proposed methods variants, including a hybrid approach with fixed-point solution.

Synchronous machine modeling precision and efficiency in electromagnetic transients

This paper presents various synchronous machine models implemented in the computation of electromagnetic transients. The paper proposes new models for achieving better computational efficiency while maintaining precision. In addition to simple infinite bus analysis, the machine models are also compared for a more sophisticated and practical case study. Precision analysis includes the surrounding network accuracy constraints.

Efficient computation of feedback-based control system equations for electromagnetic transients

This paper contributes to the accurate and efficient computation of control system equations in electromagnetic-transient simulation tools. The proposed approach is based on the formulation of a reduced rank Jacobian matrix in a fully iterative Newton method. In addition, this paper compares the accuracy and efficiency for the proposed methods variants, including a hybrid approach with a fixed-point solution.

Partial Refactorization-Based Machine Modeling Techniques for Electromagnetic Transients

Electromagnetic transient-type (EMT-type) programs solve nodal analysis or modified-augmented-nodal-analysis (MANA) formulation-based power system network equations (PSNE). The PSNE coefficient matrix can be either constant or time varying depending on the utilized synchronous machine (SM) model. Therefore, a computational efficiency comparison for the SM models requires accounting for the refactorization scheme and the utilized sparse matrix solver (SMS). In addition, MANA formulation does not require or force admittance model usage and enables flexibility while representing the SMs in PSNE. This paper compares computational performances of various SM models for a practical case and accounts for the refactorization scheme, the utilized SMS, and the SM representation in MANA formulation.

Multiphase load-flow solution for large-scale distribution systems using MANA

The unbalanced nature of distribution systems requires a multiphase load-flow solution capable of handling arbitrary network topologies and providing accurate results. The need for detailed analysis of secondary grid systems found in dense urban areas and the modeling of distribution networks including the subtransmission level requires using highly efficient and large-scale system-capable methods. In this paper, three different load-flow solution algorithms are presented using the modified-augmented-nodal-analysis formulation. The load-flow solution algorithms are compared for the IEEE 8500-node distribution test feeder using a proposed regulator tap control strategy.