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A Second Retrospective

By R. Austria, R. Tapia, K. Dartawan, M. Gutierrez, M. Infantado

For a company to have made it through its 14th year is not much to crow about. After all, businesses do this all the time. For a boutique consulting company such as Pterra, we would not crow about this either, not about the fact that the company celebrated its 14th year of incorporation on June 29th, 2018.  But we would be remiss if we said we had nothing to be thankful about, for the weight of these past 14 years is carried in terms of good memories, tough challenges and the enlightening fellowship of colleagues, friends and families all of which were intrinsic to the Pterra mosaic.

We did write a review of our first 7 years (see An Anniversary) and promised to do another in 7 more years. And we are already here, almost in the blink of an eye.

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Siting of Power Plants: A Thermal Capacity Assessment for Grid Interconnection

by Francis Luces

Introduction                                                               

For developers of power plants, one of the important factors to consider is where and how to interconnect a plant to an existing transmission network in order to reliably deliver its full output. For conventional power plants (i.e. coal, oil, natural gas, etc.), the availability of fuel supply and environmental permitting are the main considerations for siting. In the case of solar photovoltaic (PV) projects, given the availability of land area for mounting solar panels and sufficient solar irradiance, the point of interconnection (POI) to the grid can be the determining factor for siting. An assessment of the thermal capacity at potential POIs provides an effective screen for potential sites. Using transmission capacity injection analysis, developers can swiftly determine the capability of the existing network to support additional power from a new source such as a PV project. With this type of analysis, solar power project developers can know fairly early in the development process if the selected site and POI can support the plant’s output.

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The PTI Song

Click here to play: PTI

Lyrics:

PTI, we sing to thee, scene of peace and harmony; Watch the mind of each PE, spouting forth technology; We will toil from dawn til night that our brethren may delight; In a life of wealth and luxury, in a life of wealth and luxury

As you all can plainly see we have grave responsibility; In our role supervisory making corporate policy; Yet despite this awesome charge we must yet our jobs enlarge; Doing work upon computer keys, doing work upon computer keys

See the rich TAG retirees, engineers we also please; Money goes to employees like it grew on Christmas trees; Precious left for we PEs, there is not to us appease; In our life of pain and misery, in our life of pain and misery!

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Integrating Solar PV Power with Existing Distribution Circuits; Part 2

(This Blog is a continuation of an ongoing series on integrating inverter-based solar photovoltaic generation with existing electric distribution circuits. Link to Part 1)

Solar PV (shorthand for photovoltaic) generation is growing in support and implementation in part because of a supportive regulatory environment. Among the more common types of interconnection terms are NEM and FIT.

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Harmonics Limit Amount of PV on a Distribution Circuit

Harmonics is a very specialized and not widely understood topic in the electric power field which can become a major issue when inverter-based photovoltaic (“PV”) generators, (popularly referred to as solar power), are added to existing distribution circuits. This Blog provides a quick overview of the phenomena, potential negative impacts, causal conditions, and mitigating measures associated with harmonics. The bulk of the material presented here is based on an oral presentation at the SOLAR 2012 Conference of the World Renewable Energy Forum (WREF 2012) held last May 13-17, 2012, at the Colorado Convention Center in Denver.

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The Future of Transient Analysis is Bright

Yes, or at least, it’s brightening.
We make this bold observation after attending the 2012 users’ group meeting for the PSCAD/EMTDC software, held March 27-20 at a little gem of a coastal town named Castelldefels in Spain. About 60 participants (eyeball count) from universities, manufacturers, utilities, sysops, sales reps and consultants gathered together for techno-talk on the decidedly geeky subject of power system transients and PSCAD applications.

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Integrating Solar PV Power with Existing Distribution Circuits; Part 1

A wave of new solar photovoltaic (“PV”) installations for power generation is hitting many distribution circuits around the country. These installations are typically in the range of 10-2000 kW and comprise of a set of solar PV arrays or trays and inverter modules. The inverters are needed to change the direct-current produced by the arrays to the alternating current standard used by the distribution circuits. The smaller installations connect single-phase, while the larger sizes are three-phase. Interconnection voltage at the point of common coupling between the PV installation and the distribution circuit varies from 120 volt up to 34.5 kilovolt (“kV”).

The concept of integrating these new PV installations with existing distribution circuits is similar to that of interconnecting larger generators in the transmission grid; i.e., the new installation should “do no harm” to the existing system. There are three aspects to this concept as follows. (1) If the existing circuit meets specified standards or criteria of performance, the circuit should still meet the same standard or criteria when the new PV is installed. (2) If the new PV introduces a violation of standard or criteria, mitigation measures need to be included as part of the the new PV’s installation to resolve the violation. (3) If the existing circuit already violates a standard or criteria, the new PV either should not make the violation worse, or limit its impact such that the violation is not worse or even reduced or eliminated.

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Training Schedules for Generation X

Pterra conducts training in power technology subjects, not as a primary line, but in response to a perceived need. Occasionally, work in analytical consulting leads to knowledge and skills that clients and associates desire to acquire. And we are more than happy to oblige, if only to break the stream of days spent talking to computers (instead of people). Plus there is something strangely attractive in speaking to minds that are just exploring this lifetime field, electric power. We hope that most will stay on and help the industry. And we hope that some new insight will consolidate our own understanding of how electrons move. This is not to say that these courses are aimed for Gen X’ers alone. But a noticeable percentage who attend do come from that demo.

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An Anniversary

Yesterday was the 7th anniversary of the founding of Pterra, LLC.   The original team of 5 who started this journey remain, with some worthy additions.   All have grown somewhat older, hopefully wiser, and after all the contingencies encountered through the years, more resilient and united as ever.

Our core competencies remain the same: power engineering analysis, new technologies, modeling and simulation.   But service applications have grown, from the initial focus on transmission planning and interconnection of new generation, Pterra now offers distributed generation studies, solar photovoltaic and wind power modeling, applications training, assessment for high voltage direct current transmission, expert witness, among others.

No seven-year itch here.   Just some wistful reminiscing and cautionary tales for the next 70 years.   Overall, one can say that it is possible to follow the dream, to have a workplace adopted to family, health, faith, other life situations.   Or, to use an electric power analogy: to be like a lightning arrester, withstanding the normal and continuous challenges and allow all other extraordinary surges to flow.

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Report from the 2011 PSLF Users’ Group Meeting

by Ric Austria

If only for this one new feature, the trip to attend the meeting (held April 28-29 in sunny Orlando, Florida) was worth it. The new feature is …
IMAG0082-100x100
PSLF now allows “continuous” tap solutions for phase angle regulators, or PARs. Why does this matter? It matters a lot to those who work in the U.S. Eastern Interconnection (EIC) where most utilities use the competing software package, PSS/E.

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