Dynamic Transmission Network Behavior for DER Power Systems

David D. Dixon1, Chengxi Liu2 , Kai Sun2

1 Tuskegee University 2 The University of Tennessee, Knoxville

•The current absence of adequate modeling and stabilityanalysis continues to prevent DER physical integration andprimary marketing.•Emphasis is on wind power through wind farms due to it’sknown, economical advantage, continual growth , impacton power stability, and necessary application of testing.•Analysis is based on the dynamic behavior and responseof transmission networks from the wind farms (focus onthe coordination between distribution to transmission).•Generation of several simulations is to prepare for windfarm’s randomicity and various scenarios —i.e., range inwind speed and operation modes. Interactive software isused for practical implementation.•Evaluation will display the reliability of the transmissionnetwork and any other benefit to the grid and marketing atlarge

Purpose

German Distribution to Transmission Network

Case Studies

Graph of Time Domain vs. Active and Reactive Power

• DER (Distributed Energy Resources) are resources desiredto add to the power system in the near future.

• DER’s main advantage is that they are unlimited,renewable sources unlike the majority, modern sourcessuch as fossil fuels.

• The three main DER’s are wind, hydro, and solar power.• The goal of joining the sources to the bulk power system

is to ensure the “smart grid” will be both environmentallyfriendly and economical while producing enough power tomeet daily demands.

• There are many challenges planning for the addition of alarge amount of distributed energy resources.

• Unlike traditional sources, DER’s have non-conventionalstability due to their special, fluctuant characteristics. Itweakens the capability to control and modify the powernetwork operation. This calls to examine their short andlong term impact on the grid —e.g., voltage and frequencyregulations from wind fluctuations.

Introduction

[1] Y. Chang and J. Yu, "Long Term Dynamic Behavior Analysis forPower System Including Wind Farms," 2009 Asia-Pacific Power andEnergy Engineering Conference, Wuhan, 2009, pp. 1-4

References

Correlation between energy of wind power and wind speed. Pr= rated output power Vci=cut in wind speed, Vco= cut out wind speed Vr= rated wind speed Vw= measured wind speed

Active Power (Pe) and Reactive Power ( Qe) equations Vr= real stator voltage Vm= imaginary stator voltage Ir= real stator current Im= imaginary stator current

0 residual voltage (Most Disturbance)

Residual Voltage Resistance (Ohms) Reactance (Ohms)

0 0.01 0.01

0.1 (10%) 0.05 0.12

0.2 (20%) 0.15 0.25

0.3 (30%) 0.39 0.25

0.4 (40%) 0.61 0.25

0.5 (50%) 0.85 0.25

0.6 (60%) 0.61 1.71

0.7 (70%) 0.61 2.7

0.8 (80%) 2.33 0.25

0.9 (90%) 3.7 0.08

Current at 10% residual voltage Current at 50% residual voltage