Date of Award
Doctor of Philosophy
Electrical and Computer Engineering
Combined Transmission and Distribution Systems (CoTDS) simulation requires development of
algorithms and software that are numerically stable and at the same time accurately simulate
dynamic events that can occur in practical systems. The dynamic behavior of transmission
and distribution systems are vastly different. With the increased deployment of distribution
generation, especially power electronic inverters, the complexity is further increased. The
time scales of simulation can be orders of magnitude apart making the combined simulation
extremely challenging. This has led to increased research in applying coupled simulation (also
referred to as co-simulation) techniques for integrated simulation of the two systems.
In this thesis, two methods for co-simulation of CoTDS are proposed using parallel and series
computation with integration impact on numerical convergence. The proposed co-simulation
methodology is validated against commercial EMTP software. The results show the limits
and benets of applying co-simulation by using test transmission and distribution systems. A
detailed phasor domain Distribution Generation (DG) inverter model is developed for power
system dynamic simulation using which the effectiveness of the proposed co-simulation methodology
is demonstrated in dynamic studies.
The co-simulation method is then applied to model reduction where the CoTDS based
dynamic load modeling with distributed load serves as a guiding tool to calculate some of the
key aggregated WECC Composite Load Model (CLM) parameters. As a further addition, a
Reduced Distribution System Model (RDSM) is proposed with a new single-phase A/C motor
model for the WECC CLM with fractional stalling and recovery. Such a model can be used for
developing measurement based control schemes that can mitigate events such as fault-induced
delayed voltage recovery in distribution systems.
With the addition of DG in the WECC CLM, the co-simulation is applied for studying
the effect of high DG penetration on bulk transmission system dynamics in reference to the
recommendations of the IEEE 1547 standard for interconnecting distributed energy resources
with electric power systems.
Venkatraman, Ramakrishnan, "Combined Transmission-Distribution System (CoTDS) co-simulation modeling and its applications for dynamic studies" (2018). Graduate Theses and Dissertations. 17114.