Document Type

Thesis - University Access Only

Award Date

2007

Degree Name

Master of Science (MS)

Department / School

Electrical Engineering

Abstract

Voltages induced by nearby lightning can create problems for systems involving power electronics. In photovoltaic (PY) systems, there are many conductors that become exposed to the electromagnetic pulse produced by a lightning strike. These conductors can act as antennas that receive the energy of those electromagnetic pulses and pass that energy to sensitive components of a PY system, thereby seriously affecting their reliability. Even though PY modules are extremely reliable, PY power electronic converters such as charge controllers and inverters are reducing PY reliability. This is in large part because of the transient over voltages from lightning. The transient voltages that are being induced were postulated to range from several tens to thousands of volts, but a small amount of field data has been published until now to verify this. On the AC (utility) side of inverters, quantitative data and recommendations for use in specifying surge suppression devices are readily available, but data for DC-side protection are much more sparse. This project deals with the measurements of lightning-induced transient voltages induced in PY arrays using a data logger that has the capability of capturing very short term events, approximately microseconds in duration. The datalogger uses MATLAB as its PC interface for acquisition and analysis. The results obtained are used to develop guidelines for DC-side transient suppression in PY power electronics. The data recorded indicate that lightning-induced over voltages in PY arrays can significantly exceed the absolute maximum DC input voltages of many commonly-used PY power electronic converters. The data suggested that induced voltages of 163 Y/module for negative polarity transients and 192 Y /module for positive-polarity transients are possible. For testing of protective devices in PY power electronics, the IEEE standard ring waveform with a 100-ns rise time was suggested by the data.

Library of Congress Subject Headings

Transients (Electricity)
Photovoltaic power generation
Power electronics

Format

application/pdf

Number of Pages

73

Publisher

South Dakota State University

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