Wieserman, Laura
(2017)
Developing a Transient Photovoltaic Inverter Model in OpenDSS Using the Hammerstein-Wiener Mathematical Structure.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Photovoltaic (PV) modules (direct current) have continued to decrease in price over the past decade causing the number of PV installations to increase. With increase in use of PV renewable resources come more interconnections to the electrical power grid and hence system protection challenges for planning engineers. PV inverters (direct current to alternating current interconnections) do not behave like traditional generators having rotational inertia and long-lived electrical time constants. In contrast, inverters have no inertial mass and very short time constants. Manufacturers do not provide inverter design details. Therefore, current inverter circuit models available for studying inverter behavior and completing inverter grid integration tasks are not adequate. In addition, the inverter models currently used by planning engineers only provide steady state solutions; not accurate time-domain results for rapid load changes especially during electrical circuit fault conditions. Inadequate and inaccurate planning models result in unreliable system protection designs, leading to possible operational failure, mis-coordination of protective equipment, and system damage. Valid transient models are necessary to plan for unusual circuit conditions including overvoltages, grounding conditions, and anti-islanding on electric grid feeders connected to photovoltaic resources or utilities desiring to add photovoltaic resources to an existing feeder.
This research makes an original contribution by providing a modeling solution for solar PV inverter transients using the Hammerstein-Wiener (HW) mathematical structure. The analysis is based on laboratory test data from single-phase, micro, and three-phase inverters. Data was collected during open-circuit, short-circuit and voltage sag events. Each inverter was tested at multiple output power levels and multiple tests were run for each case to account for point-on-wave effects on the transient magnitudes. The HW framework, which integrates linear dynamics and nonlinearities, provides a framework for the transient PV inverter model. The model was incorporated into an open source distribution simulation software; OpenDSS. Test results show that PV inverters cause significant over-voltages and over-currents during transient events, but these have been difficult to predict accurately in simulations. The OpenDSS model provides a solution for modeling these nonlinear behaviors for design and operating studies and can be expanded to incorporate other power system components.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
1 February 2017 |
| Date Type: |
Publication |
| Defense Date: |
16 November 2016 |
| Approval Date: |
1 February 2017 |
| Submission Date: |
21 November 2016 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
154 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Electrical and Computer Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Photovoltaic Inverter, OpenDSS, Hammerstein-Wiener, Photovoltaic Inverter Transients, Photovoltaic Inverter Modeling |
| Date Deposited: |
01 Feb 2017 20:16 |
| Last Modified: |
02 Feb 2017 06:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/30339 |
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