Distributed generation has become a viable option and is gaining wider acceptance to utilities, customers, and independent power producers. While DG offers many advantages, the utility typically requires system impact study for interconnecting DG to the existing electric grid to ensure it would not adversely impact the operation, reliability and safety of the grid. This course covers the technical aspects of DG integration from the viewpoint of both independent power producer and utility. Specific topics include: islanding, steady state power flow, voltage regulation, short-circuit, protective relaying, power quality (flicker and harmonic), power factor, system stability, grounding, and ground fault overvoltage.

Wind farms by the nature of their design and operating characteristics are susceptible to a variety of overvoltages.  Hence it is always important to conduct studies and tests of the various levels of overvoltages and how the equipment at the wind farm are able to withstand with or without mitigation measures.  In this Blog, we will provide an overview of the issues, the analytical approach and potential mitigation.  Then, we demonstrate how these are applied to a sample wind farm.

The seemingly innocuous flickering of lamps could be a new technical battleground for the further growth and spread of photovoltaic (“PV”) electric power. On one side of the impending conflict is the flicker standard, a venerable reference that could very well trace its roots back to the advent of the electric age. On the other side are the new darlings of the power industry — environment-friendly, renewable solar power. The one thing about solar power is that in bulk amounts, its units need to be connected to existing electrical systems, and a side effect of this integration is the production of flicker. The more PV devices connected to the same electrical circuit, the more flicker is produced and the closer the level of flicker is to the allowable limit defined by the flicker standard.

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!

(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.

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.

“Harmonics Issues that Limit Solar Photovoltaic Generation on Distribution Circuits,” by K. Dartawan, L. Hui – Pterra, M. Suehiro – Maui Electric Co., presented at SOLAR 2012, World Renewable Energy Forum (WREF 2012), May 13-17, 2012, at the Colorado Convention Center in Denver.

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.

As an analytical consulting firm, Pterra regularly uses about half a dozen engineering software, and about the same number on an occasional basis, to be able to conduct its services. The software are necessary to be able to simulate complex physics and market conditions and/or large scale databases. In addition, we try to use the same software that our clients use so that part of our deliverable is an updated system model or database.

One more item to add to the list of technical items to consider when interconnecting solar and wind farms is grounding. The grounding issue often appears when (a) integrating solar power inverters or wind turbines to existing distribution circuits, or (b) designing collector systems for solar and windpower farms.