NAU - Team ELDO

Experiences With the Design Process - The Proposal


One two major phases in our project was the production of a proposal to be submitted to APS for around ~25,000 to cover the hardware costs of a portable transient detection system that could be used on high voltage (>15kV) distribution lines. Our design of the portable transient detection system has four major components, an optical current transformer, oscilloscope, computer, and storage container. In the proposal we have done much to identify parameters that govern successful interaction of the major components. For example, the output voltage of the current transformer must be less than the input voltage of the ocsilloscope. Many of these parameters of interaction are not listed on the manufacturers data sheets, so we had to use other methods to track them down such as making (many) phone calls and taking a trip to Phoenix to ask a technician about the current transformer and its applications in person.

In this stage there were two major milestones. Each of the team members was assigned one major component, and needed to deliver a section of the proposal about their component consistent with the other members findings as far as interconnection parameters are concerned. The other major milestone is the compilation of these sections into a cohesive and complete proposal. There was no hardware or software tools used during this phase beyond ordinary text processing programs and many phone calls.

Our initial goal for the project was to actually purchase and set up a portable transient detection system. We had a budget of $5,000 to cover hardware costs. Unfortunately every optical current transformer we looked up cost over $15,000. We looked at non-optical current transformers, but they did not meet the parameters that defined our system. The important parameters that were not met by standard current transformers were due to that a high-voltage standard current transformer is quite heavy, and thus the portability of our system was comprimised. Additionally, standard current transformers work via induction and this posed a danger to the hardware connected to the transformer when very strong transients caused by lightning or another strong event occured. So, the team along with Dr. Kipple made the regrettable tradeoff to not build the system, and instead write a proposal to fund the system as we envisioned it.

We encountered a number of problems during this phase. The major hurdle was finding answers to questions regarding the current transformer. For instance, it was not clear from the website how the components of the current transformer fit together, whether they were waterproof, what cabling was needed to interconnect the device, etc, etc. We had to make numerous calls to the manufacturer that were very particular, and thus it was difficult to find a single contact to answer all of our questions. When questions were answered and others cropped up, it felt as if we were pestering the current transformer company. Eventually we worked out a visit to Alstom in Phoenix which made the current transformers. During this visit we will get to see an installation in person and ask questions from a knowledgeable engineer.