Wednesday, May 29, 2013

SINGLE POINT GROUNDS ON DIFFERENTIAL CIRCUITS

In differential relay protection schemes, two or more currents are compared to ensure rapid detection of fault current within a certain "zone." The basic concept is that under normal conditions, the "sum of currents in" must equal "sum of currents out,"allowing for some error margin tolerance (restraint). When current is feeding a fault in between these current sensors, much more current enters the zone than current leaving (if any at all). For example, an unfortunate cat creates a fault current path from A-phase to the case or ground of a transformer. 

This type of protective circuit can issue a trip or "open" signal to switches that quickly isolate and extinguish the fault that could reach thousands of amperes, limiting damage to equipment, and possibly saving human life, though it only takes a fraction of a second many cases for lethal consequence: only safety work processes and procedures can mitigate such danger.  

In such differential circuits, there should be a single ground for each zone located nearest the respective relay. This must be electrically verified through a single-ground test during commissioning.

During a fault condition, multiple grounds allow a different ground potential rise for each current transformer. The result is a significant current flow through the current sensing (CT) circuit that is not representative of the primary current. 


This ground loop typically creates a potential across the operating coil or input of the differential relay causing the relay to pick up as though a fault exists in the relay's protective zone. Tripping a differential relay due to a fault external to the zone of protection is one of the most common types of nuisance trips. 


These nuisance trips may not only shut down the load, but may require a maintenance crew to spend days in testing to determine that no real problem exists in the differential zone. Further, the actual problem may go uncovered until the system is re-energized into the original fault.


Further reading:

http://www.powellind.com/main/Uploadpdf/ptb%2087%20current%20transformer%20grounding.pdf"


Nelson Abreu & 

guest writer Jeff Velena, Southern CA


 

Tuesday, January 1, 2013

$5 lamp powered by gravity!

GravityLight aims to provide clean, efficient light for the 1.5 billion human beings on this planet who still do not have reliable access to electricity and use kerosene-powered lamps.

Read more about this brilliant product, another example of social benefit meeting business, at Venture Beat blog.

Saturday, December 29, 2012

EPA chief Lisa Jackson has resigned. Is Obama's #climate silence to blame? Secret email account use?

  
There has been no fiercer champion of our health and our environment than Lisa Jackson, and every American is better off today than when she took office nearly four years ago. For that, we are deeply grateful to Lisa for her service, and to President Obama for having appointed her to this vital position.
Lisa leaves giant shoes to fill. And her successor will inherit an unfinished agenda that begins with the issuance of new health protections against carbon pollution from existing power plants—the largest remaining driver of climate change that needs to be controlled.
       – Natural Resources Defense Council President Frances Beinecke

 
Congressional Republicans, however, won't be sad to see her go. Nor will the lobbyists who thought she was a "job killer." Caught between their hostility toward regulation and the Obama administration's lack of emphasis on climate change, Jackson was unable to nix the Keystone XL oil pipeline, a planned route for bringing tar sand oil from Canada down to Texas. When confronted on the issue, Jackson simply said that holding conversations about the project is "awesome." She also wasn't able to get the EPA to take meaningful action on hydraulic fracturing, even after the agency found evidence that the practice contributes to groundwater pollution.
The Atlantic Wire 
 
One of her biggest achievements is that she succeeded in brokering a deal with automakers to double fuel efficiency standards by 2025. That's going to save consumers $100 billion a year at the pump, it's going to cut our carbon emissions from automobiles in half, and it's going to save us 3 million barrels of oil every day.
 
Natural Resources Defense Council Assoc Dir Bob Deans
...She was the first administrator in decades to champion wholesale reform of the Toxic Substances Control Act. As that effort stalled in Congress, she redoubled the agency's commitment to review and regulate toxic chemicals through aggressive use of existing law. She stood up to polluters time and again—whether they were fouling America's air with smog or our drinking water hexavalent chromium—and simply because she was doing her job she became a target of anti-environmental ideologues. But to the people and communities she protected across the country, Administrator Jackson was a hero..
- Environmental Working Group's Ken Cook

EPA's vehicle greenhouse gas rules, will save consumers $1.7 trillion at the pump by 2025, and eliminate six billion metric tons of GHG pollution.
- EPA
A hero to the environmental movement and a constant thorn in the sides of Republicans and the energy sector, outgoing Environmental Protection Agency Administrator Lisa P. Jackson presided over one of the most controversial and dramatic periods in the agency’s history.
She made her mark by helping craft new automobile fuel standards, imposing a ban on new coal-fired power plants, and being among the loudest in calling for action to combat climate change.
But Ms. Jackson, who announced her resignation Thursday after four years at the helm of the EPA, also sustained several legal defeats and embarrassments during her tenure. Among Republicans and many in the fossil-fuels industry, she has dragged the agency’s scientific credibility to an all-time low after failed attempts to tie hydraulic fracturing to water contamination in Texas, Wyoming and Pennsylvania.
She also is departing as the EPA and two House committees investigate her use of secret email accounts.
Less than a year ago, one of Ms. Jackson’s top deputies, Al Armendariz, was forced to resign after promising to “crucify” oil and gas companies in order to set an example for the rest of the industry.
But those setbacks, as far as Ms. Jackson and President Obama are concerned, pale in comparison with the accomplishments of the past four years.
– Washington Times
 
Read more on: NPR, Mother Jones, Huffington Post Green, Fox News

Friday, December 28, 2012

California Lithium Battery increases energy density by 3 times and specific anode capacity by 4 times over existing LIBs

Battery technology is critical for our modern world of portable devices and increasing demand from trends like electric vehicles and distributed energy storage, areas which can play an important role to face our aging power infrastructure and climate change. The press release below illustrates one startup that has achieved great advancements. Just as microprocessor and computer memory advances have revolutionized our society, we hope for a similar "Moore's Law" acceleration in this arena.

Los Angeles (PRWEB) October 26, 2012

California Lithium Battery, a finalist in DOE’s 2012 Start Up America’s Next Top Energy Innovator challenge, has announced the record-setting performance of its new “GEN3” silicon graphene composite anode material for lithium-ion batteries (LIBs). Independent test results in full cell LIBs indicate the new GEN3 anode material, used with advanced cathode and electrolyte materials, increases energy density by 3 times and specific anode capacity by 4 times over existing LIBs.

For eight months CalBattery has been working with Argonne National Laboratory (ANL) to commercialize a novel lithium battery anode material for use with advanced cathode and electrolyte materials to achieve new levels of LIB performance. The work is showing extraordinary results. Independent full cell tests reveal unrivaled performance characteristics, with an energy density of 525WH/Kg and specific anode capacity 1,250mAh/g. In contrast, most commercial LIBs have an energy density of between 100-180WH/kg and a specific anode capacity of 325mAh/g. “This equates to more than a 300% improvement in LIB capacity and an estimated 70% reduction in lifetime cost for batteries used in consumer electronics, EVs, and grid-scale energy storage,” said CalBattery CEO Phil Roberts.

The key to this new GEN3 battery material is the use of a breakthrough Argonne silicon graphene process which stabilizes the use of silicon in a lithium battery anode. Although Silicon absorbs lithium ten times better than any other anode materials it rapidly deteriorates during charge/discharge cycles. CalBattery has worked at Argonne and other facilities over the past year to develop this new anode material to work in a full LIB cell with multiple cathode and electrolyte materials. The superior results of the development program at ANL leads the Company to believe that this advanced anode material could eventually replace conventional graphite based anode materials used in most LIBs manufactured today. This novel composite anode material is suitable for use in combination with a variety of existing and new LIB cathode and electrolyte materials that will help dramatically improve overall battery performance and lower LIB cycle cost – effectively storing electricity at a cost competitive with energy produced from fossil fuels.

CalBattery is now in the process of fast-tracking the commercialization of its GEN3 breakthrough battery anode material. Over the next two years the Company plans: (1) to produce and sell its si-graphene anode material to global battery and EV OEMs, and (2) U.S. production of a limited quantity of specialized batteries for high-end applications. “We believe that our new advanced silicon graphene anode composite material is so good in terms of specific capacity and extended cycle life that it will become a graphite anode ‘drop-in’ replacement material for anodes in most lithium ion batteries over the next 2-3 years,” said Roberts. The Company believes this transformational technology will change the way LIB power is produced, managed, and stored, especially if it can lead to LIBs being produced for under $175/kWh and directly compete with the cost of energy from fossil fueled power generation.

About CalBattery (http://www.clbattery.com)
CalBattery is a portfolio start-up company headquartered at the Los Angeles Cleantech Incubator (LACI), which was started by The City of LA and the LA Department of Water and Power in 2011. CalBattery plans to set up silicon graphene anode material and LIB manufacturing operations in the Los Angeles area based on interest in its advanced Li-ion battery material from U.S. and international customers.

Thursday, December 27, 2012

Will Water Become the Chief Commodity of the 21st Century? (SciAm)

The world faces a growing number of challenges surrounding water, from freshwater supply to flooding

South Bend, Ind., avoided $120 million in upgrades and conserved millions of gallons of water by becoming one of the first cities on the globe to use cloud computing to manage its water systems.
In Oregon, local officials cooled down water from wastewater plants by planting trees near riverbanks rather than using cooling equipment, lowering investment costs at the same time.

The Department of Energy, meanwhile, is working with governors and transmission officials in Texas and the western United States on a multi-year computer project to find the best locations for new power plants faced with growing scarcity in nearby water resources to cool down their operations.
These examples underscore the many options available to alleviate a growing global water crisis exacerbated by climate change, water experts said yesterday at forum in Washington, D.C., sponsored by Growing Blue, a group created by Veolia Water in consultation with the United Nations, Columbia University and water conservation groups.

"Water is posed to be the commodity of the 21st century," said Richard Sandor, an analyst at Environmental Products, who also founded the Chicago Climate Exchange.
Current statistics -- outlined yesterday in a new report from IBM at the event -- highlight the challenges facing the water sector on everything from drought to storm runoff.

Between 2005 and 2030, the number of people living in areas where water demand will exceed available supplies could rise 40 percent, from 2.8 billion to 3.9 billion, the company said.

A water trading system to conserve supplies
By 2070, the value of flood-exposed economic assets in 136 major ports could reach 9 percent of global gross domestic product. In global agriculture, 35 percent of annual water is wasted because of "poor resource management."

In the United States, there will be a need for 165 percent more water by 2025 above 2000 levels, the report says. Energy use -- such as use for cooling down power plants during hot summers -- accounts for 49 percent of U.S. water demand.

Tight supplies will be further squeezed by a potential shortage of workers managing stormwater, drinking water and wastewater systems, said Mary Keeling, a manager at IBM. The issue is "often overlooked," she said.

In the United States, the average water utility worker is 44.7 years old, with a retirement age of 56, Keeling said. That raises serious questions whether utilities will have the personnel they need to address problems such as drought, she said.

For Sandor, an obvious answer to future water shortages is water trading, which would allow water-stressed areas to purchase supplies from other regions. As one example, he said that it takes the same amount of water to make $250,000 worth of alfalfa as it does to run an Albuquerque, N.M.'s computer chip plant, yet farmers "can't sell their water rights" in the state, he said.

While it could take 10 to 20 years to build a water trading system in a given region, it is an idea that would boost conservation tremendously, he said.

The idea is a controversial one. A study in the Journal of the American Water Resources Association published this spring outlined the potential difficulties of setting up a water trading system in the American West, including the fact that there is not an umbrella authority over states in the 1922 Colorado compact. Some critics also are concerned about trading altering river flows and disrupting hydroelectric dams, among other things.

Alberta could lead the way
Yet Sandor said Alberta, Canada, could be a first mover. The province faces multiple pressures of growing oil extraction, business development and population growth in an arid climate, and there are preliminary discussions about the concept (ClimateWire, Aug. 3).

Source:
http://www.scientificamerican.com/article.cfm?id=will-water-become-the-chief-commodity-of-the-21st-century


Sunday, December 16, 2012

#Water Crisis in U.S.: Growing populations, rapid urbanization and chronic underinvestment

In a previous post about water conservation and smart metering, we highlighted that the use of advanced metering infrastructure can help identify leaks by comparing similar water flows at different points, similar to electric theft or fault schemes. Smart meters can also provide more awareness on usage and stimulate a conservation effect.

Xylemic Inc produced an interesting infographic about the water crisis in the U.S., the level of awareness among Americans, and some enlightening stats.

The water crisis is intimately related to the energy crisis, as most energy generation options are water intensive, as does hydraulic fracturing ("fracking") used in the natural gas extraction boom.
"The World Meteorological Organization estimates, assuming the renewable water resources will remain unchanged, that the number of countries facing water stress will increase from 29 today to 34 in 2025."

Friday, December 14, 2012

The Digital #Lighting Revolution by Dan Koeppel #efficiency

Following up on our interview "Why new-generation LED lighting is set to make cities greener with Dr. Torben Riise of Green Air International," here's another look at the present and future of digital lighting.

The Lighting Revolution Is Now

By Dan Koeppel


The age of Thomas Edison was supposed to come to an end on January 1, 2012. That's when the Energy Independence and Security Act of 2007—a congressionally mandated ban on incandescent light bulbs—was meant to go into effect.

Instead, the act became a political cause, used as an example of government interference in consumer choice and the free market. And in the final weeks of 2011, it was blocked: the budget agreement between Congress and the Obama administration included a delay in enforcing the law.

The block extends only through the end of 2012, and attempts on both the federal and local levels are now being made to reverse the ban permanently. But the experts are in agreement: the incandescent is becoming obsolete, they say, destined to be replaced by more efficient and environmentally sound alternatives that are already on store shelves.

Here is what you need to know about where lighting technology has come, and where it's going.

The Problem with Incandescents

First things first: Edison's 125-year-old technology has some major flaws. Incandescent bulbs produce light via a filament that glows when electricity heats it. The light is attractive to many eyes, but the bulbs don't last long—bout 1,500 hours maximum—and they're inefficient, with roughly 90 percent of the energy they consume given off as heat, rather than light.

The U.S. Department of Energy estimates that replacing a single 100-watt incandescent bulb with a comparably powered CFL bulb saves a consumer about $6 overall, and energy devoted to lighting could be cut by as much as 80 percent if more efficient bulbs were adopted.

THE FIRST OPTION: CFLs

The most widely used alternative to incandescents today is the spiral-shaped compact fluorescent lamp, or CFL, which is filled with gas that creates light when electrons from the power source flow into the tube and collide with the gas molecules.

Lighting Alternatives - LED Lights

The product is an engineering marvel, invented in 1974 by Ed Hammer, then an engineer at General Electric. Fluorescents usually needed to be long to work properly, which is why they mostly appeared in large spaces like warehouses and schools, but Hammer found a solution in the bulb's spiral shape. Creating them, however, involved painstakingly heating and curling glass tubes by hand, and General Electric ultimately shelved the project. It wasn't until the 1990s that GE competitor Philips, today the world's largest lighting manufacturer, introduced the first successful version of the product, called the "Tornado" bulb.

CFLs are still more expensive than incandescents. But according to Michael Siminovitch, director of the Lighting Technology Center at the University of California Davis, because they last longer and require far less electricity to produce light, they should—in theory—pay for themselves. Nonetheless CFLs have acquired a bad reputation. For starters, Siminovitch says, there were exaggerated longevity claims early on, and more importantly, the bulbs don't dim, they produce an unnaturally colored light that doesn't appeal to many consumers, and they contain toxic mercury.

The waste issues associated with mercury are now being remedied by disposal initiatives, such as the bulb return programs offered by Home Depot, as well as consumer education on how to handle broken bulbs. (The Environmental Protection Agency's how-to document for handling a broken CFL is three pages long). But those hassles may mean the bulb's reputation is unrecoverable, says Siminovitch.

LEDs BRIGHT FUTURE?

Perhaps the most promising new lighting technology is light-emitting diodes, or LEDs. Unlike incandescents and CFLs, LEDs are digital—they're based in circuitry—and they are easier to dispose of and longer-lasting than CFLs.

They're also expensive (currently starting at about $20 per bulb) and heavy, and they run hot to the touch, enough so that currently available products require unattractive cooling methods like heat-dissipating fins.
The U.S. Department of Energy has encouraged the adoption of LED bulbs by offering bounties to companies that create products meeting a set of criteria designed to avoid the problems with CFLs. In 2011, the L-Prize (a government-sponsored technology competition) was awarded to Philips, which became the first company to introduce a relatively dimmable LED bulb that produced light equivalent to that of a 60-watt incandescent.

The Philips product remains unproven. Nobody knows how long they'll last in real-world usage, and with bulbs costing as much as $50, few consumers have shown a willingness to make a leap of faith. Home Depot, the country's largest lighting retailer, doesn't appear to be terribly optimistic. "I don't want to say it's exorbitant, but if a customer is only looking at the price, they could come to that conclusion," Brad Paulsen, the company's manager for lighting products, told The Washington Post in March 2012.

Yet LEDs are following an innovation curve akin to other high-tech items like computers and digital cameras. Basically, LEDs are semiconductors, and like all solid-state technology, they tend to get better and cheaper as time passes. In 1999, a researcher named Roland Haitz, then heading up semiconductor R&D at Hewlett-Packard, coauthored a paper that became the lighting industry's manifesto. By charting the historical prices of LEDs and projecting forward, Haitz estimated that the amount of light they produced would increase by a factor of 20 per decade, while the cost would correspondingly drop by a factor of 10.

As with Moore's Law, which predicted decreasing prices for increasing computer power, Haitz's Law has played out in the marketplace. Right now, Haitz says, LEDs are on the verge of widespread affordability, and if consumers were willing to factor in long-term savings and look at LED bulbs as an investment, they'd embrace them.

The Next Gen of Lighting

The first wave of forms after LEDs will likely use organic LEDs, or OLEDs, which have diodes based in carbon, rather than today's more expensive silicon. These lights would be so efficient that they could be powered for decades on a single small battery, and could be produced on flexible plastic sheets capable of being hung virtually anywhere.

Early prototypes of these sheets are being developed at the College of Nanoscale Science and Engineering at the State University of New York in Albany. Paul Tolley, the program's director, says that OLED-based panels are groundbreaking in part because they don't require a socket. "You no longer have to adapt what you're building for that space," he says. "Instead, you've got limitless possibilities; it really changes how we look at everything related to lighting."

Ironically, innovations like OLEDs may be adopted first in the Third World, where existing infrastructure like sockets doesn't need to be widely replaced—although Tolley does predict that already-wired places like the U.S. and Europe will catch up.

After OLEDs, other technologies-like quantum dots, a nanocrystal whose ability to emit varying light colors can be fine-tuned based on the crystal's size—are probably 20 to 30 years away, says Tolley, who notes that these will have even greater energy efficiency and flexibility. From there, he says, consumers will begin to see lighting more as "a series of modular applications, with lots of solutions—a series of niches, rather than a place where one particular technology dominates."

The Near-Term Outlook

For now, expect incandescents to become harder to find. The 2007 act, if its block expires at the end of this year, mandates that 100-watt incandescents improve their energy efficiency by 25 percent between 2012 and 2014, a goal so close to impossible that most manufacturers won't even try. Although some bulbs are exempt—those under 40 watts, three-way bulbs, appliance and other specialty bulbs—the same mandate would apply to 75-, 60-, and 40-watt bulbs over the next three years. Manufacturers also have the global situation to keep in mind: full or partial incandescent bans are now in effect in much of the world, including the European Union.

Bulb companies are already rapidly switching over to LED production, although CFLs could theoretically make a comeback because they're significantly more affordable. Hammer is working on cleaner, more versatile CFLs with a Chinese company called TCP that went public in the U.S. in April 2012. A company called VU1 is offering bulbs using what it calls Electron Stimulated Luminescence (ESL), a technology that is similar to CFLs but contains no mercury. And Philips is offering a slightly less efficient version of its L-Prize-winning LED bulb for about $25.

Technology made inevitable through regulation isn't ideal, says Siminovitch, who adds that if such rule-making were needed, he'd prefer to see the traditional socket banned instead, which would set things in motion very quickly. Will that happen? "Absolutely not," he says. The revolution is definitely coming, he predicts, "but slowly."

Dan Koeppel is a writer specializing in science, technology, nature, and the outdoors. His work has appeared in Wired, Popular Mechanics, Popular Science, and The New York Times.

Source:
http://individual.troweprice.com/public/Retail/Planning-&-Research/Connections/Lighting/The-Lighting-Revolution-Is-Now?PlacementGUID=07FC8E36-D4E5-45BB-BCD1-A8790B9576AD