Induction Machine Test Case for the 34-Bus Test Feeder -Distribution Feeders Steady State and Dynamic Solutions Induction Machine Modeling for Distribution System Analysis panel IEEE PES General Meeting Montreal, Canada June 21, 2005 By N. Samaan, T. McDermott, B. Zavadil and J. Li
Agenda Overview of the used software package Test case description Dynamic model for the wind turbine Steady state results Dynamic simulation results Conclusions
DIgSILENT PowerFactory version 13.1 Based on object oriented approach which makes it more suitable for detailed representation of the wind turbine Performs balanced and unbalanced load flow, short circuit, transient, harmonics and reliability analysis Both SI and English Units are available Custom control models can be built for different types of wind turbines.
Test Case Description G1 848 T1 822 846 820 818 864 844 842 800 802 806 808 812 814 850 810 816 824 826 858 832 852 834 860 888 890 836 862 T2 838 G2 840 828 830 854 856 IEEE 34 Node Test Feeder with two wind turbines installed at nodes 848 and 890
Generic Dynamic Model for Squirrel Cage Induction Generator with Pitch Angle Controller Pitch Angle Controller Aero Dynamics Model 2-mass model for the shaft Squirrel cage induction generator model
Pitch Angle Controller Control parameters are need to be given with the generator data (Ka, Tr, Ta, beta_max, beta_min)
Turbine Model Represented by a set of algebraic equations VW: is the wind speed which can be fixed value or can vary with time
Shaft Two Mass Model Needed data: Turbine damping, turbine inertia, shaft- Stiffness, torsional damping and turbine nominal rotor speed
Squirrel Cage Generator Model Linear induction machine model including slip dependent rotor impedance This model initializes itself to match the terminal power of the machine to the power of the generator in the load flow case. The slip and reactive power consumption of the induction machine are determined as needed to match the specified power
Limitations of DIgSILENTS Power Factory All loads have been presented as PQ loads, it was not clear for authors how to represent Z or I loads The program allows the consideration of load voltage dependency by adjusting some parameters. The program does not allow different settings for each phase in 3-phase regulators. The sequence impedances for each line type has been calculated approximately using the corresponding impedance matrix given in the test case. Distributed loads have been concentrated at the middle of the its line
Steady State Results By mistake, results reported in the paper assumed wind generator output power to be 600 kw rather than 660kW In this presentation all reported results are given after adjusting the output power of each generator to be 660 kw. G1 DiGSILENT DSS Total P 659.97 kw 660 kw Total Q 330.7 KVAR 327.1 KVAR G2 Total P 660 kw 659.8 kw Total Q 327.4 KVAR 334.3KVAR
Power Injected into the Feeder (Node 800) Phase DiGSILENT DSS (P+jQ) (P+jQ) 1 303 + j545 285+ j 398 2 196+ j504 193+ j 318 3 197+ j479 146 + j 235 Total 696+ j 1530 625 + j 951 We are investigating the reasons behind the deviation in real power of phase 3 and reactive power for all phases
Dynamic Simulation Network disturbance is represented by a 3 phase short circuit fault with zero impedance at the substation high voltage bus. The fault occurs at t=2 seconds and lasts for 150 µsec. The electromagnetic transient time step is 0.1 µsec.
Voltage Magnitude G1 G2 Node 834
Instantaneous waveforms for G1 V I P
Instantaneous waveforms for G1 (Zoom in)
Conclusions This paper shows simulation results for unbalanced steady state load flow for IEEE 34-bus test feeder with two wind turbines installed using DIgSILENT Power Factory There are difference in results obtained than those obtained by other panelists Generic dynamic model has been used to represent the wind turbine for transient simulation More data are needed to be added to the test case to characterize the generic model of the turbine dynamics models for transient simulation