NEMA Currents : grid

Press the EMP Key

Hsieh, Eric — Wed, 02 Sep 2009 18:57:00 GMT

A nuclear explosion outside the earth's atmosphere produces an electromagnetic pulse (EMP). While there has been recent Hill, media, and fictional attention on the subject, EMPs have been a threat since the nuclear age. The grid does have certain vulnerabilities, and this post outlines what is (or isn't) at risk from EMP damage. While heavy power system assets such as switches and transformers are largely immune to immediate EMP interference, EMP-induced surge currents could overwhelm some protective systems. More importantly, the modern monitoring, communication, and control equipment are vulnerable to damage from an EMP. Such an attack could cripple power system operations. Detailed writeup follows.

Induced voltages will damage integrated-circuit systems

Unless specifically hardened, semiconductor-based control systems are the most vulnerable grid device. Voltages as low as 50V can destroy the semiconductor materials inside a chip. An EMP can induce an electric field in the range of 10-50kV/m, easily damaging unshielded chips. In addition, any wire (such as a power cord, an antenna, or a network cable) aligned with the EMP can carry damaging voltage spikes inside a device.

External grid monitoring and communication equipment are not normally shielded against EMPs. Advanced meters and syncrophasors are examples of new devices whose microprocessors would be destroyed or damaged by an EMP. Even if the underlying power equipment is operational, an EMP will likely cause failures or misoperation of grid control systems. If remote devices are partially damaged, the central control center may not differentiate between grid fault conditions or misreporting sensors. Special protection systems may deploy inadvertently.

Remote device shielding is likely to be expensive and cumbersome. Instead, it may be more cost-effective to harden only select critical facilities and maintain a replacement inventory for others. Operators may choose to install redundant systems, as devices rarely fail in the same manner. Operators could also codify procedures to fall back on older electromechanical controls.

Heavy power equipment will likely survive an EMP

Large power equipment is often already hardened against electromagnetic field (EMF) interference. For example, power transformers are usually enclosed in metal chambers. IEC 60076-1 specifies that power transformers may not emit nor be vulnerable to electromagnetic disturbances. [1] The chambers that keep in EMFs will also keep out EMPs. [2]

The substation can also act as an EMF shield. Like transformers, some substations are constructed with metal cages in windowless buildings to reduce EMF radiation, which also protects the control systems inside. However, lead wires could let in surge currents or propagate EMPs. Complete protection would require the same isolation procedures used for computer systems.

Induced currents on long transmission lines can damage power equipment

When aligned with a long transmission line, an EMP induces very high current and voltage for a short duration, on the order of 10-50 nanoseconds. While the crest currents from EMPs and lightning are about the same order of magnitude, the EMP crest voltages rise much faster than a lightning strike. The fastest voltage rise from lightning has been estimated at 10 MV per microsecond, while the EMP rise can exceed 30 MV per microsecond. [3]

Surge arrestors are the primary protective device that guard against lightning strikes. In the U.S., surge arrestors must meet performance standards as described in ANSI/IEEE C62.11/NEMA LA-1. However, surge arrestors that meet only these standards may not respond to the fast-rising EMP quickly enough to prevent damage to the protected device. If the arrestor cannot dissipate the current, the primary device would be exposed to a surge similar to a lightning strike, with possible consequences being insulation degradation/failure or structural deformation.

Some authors have suggested additions to these standards to withstand most EMPs. [4] Indeed many companies market such devices today. The cost of surge arrestor hardening is likely to be small compared to the protected equipment (i.e. transformers). In 1989 researchers tested nineteen distribution transformers for susceptibility to an EMP-induced surge current. Every transformer with an onboard arrestor survived the surge, while about half the transformers without self-protection failed. [5]

If the arrestor fails, the likelihood of power equipment damage is uncertain. Most power equipment can withstand surges under a voltage rating known as the Basic Impulse Level (BIL). While an EMP can create higher voltages than the BIL, the EMP surge duration (nanoseconds) is much shorter than the BIL test wave (microseconds). Because the total dissipated energy is comparable, the insulation in transformers, circuit breakers, switches and other equipment may well survive an EMP surge.

Multiple EMPs may interrupt power system operations

Some EMP warfare scenarios envision multiple blasts over a short duration. Many fault reclosers are designed to "lock out" if several faults occur rapidly, such as four trips in three minutes. Since an EMP affects all devices over a wide geographic area, multiple EMPs could lock out a large number of reclosers, resulting in islanded areas or lost load. Restoration of transmission paths would require cumbersome manual switching, especially if remote communications are also interrupted.

DC ground currents from solar storms can overhead equipment

Every 11 years, a stream of charged particles flows past the earth, inducing a complementary DC current near the planet's surface. These currents can saturate the cores of neutral-grounded power transformers. During previous solar storm cycles, operators found some metallic power equipment glowing red hot. In addition to solar storms, monopole operation of HVDC lines and cathodic pipeline anti-corrosion systems can also cause similar neutral grounding problems.

To prevent core saturation, operators can install a capacitor between the device and ground, which provides AC grounding but interrupts the DC path. Various manufacturers provide pad-mounted capacitors for this purpose, which can cost in the range of $50k, significantly less than the million-dollar transformers that need to be protected.

After an initial EMP blast, there may be residual currents that mimic the solar storm current. However, since these currents dissipate quickly (within seconds), grounding measures for solar storms may be sufficient to guard against the secondary EMP wave.

Conclusion

Because existing EMF reduction and lightning protective measures can also protect against EMPs, the cost of heavy power equipment EMP protection is not likely to be prohibitive. However, semiconductor-based communications and controls will be vulnerable to an EMP. Proper shielding, spare parts, redundant systems, and electromechanical fallbacks will help the grid operate after an EMP attack.

[1] IEC 60076-1, "Power Transformers

[2] Conversation with engineers from Waukesha Electric, August 10, 2009

[3] Marable, Baird, and Nelson, "Effects of Electromagnetic Pulse on a Power System," Oak Ridge National Laboratory, Interaction Note 173, December 1972.

[4] Marable, Barnes, Nelson, "Power System EMP Protection," Oak Ridge National Laboratory, Interaction Note 246, May 1975.

[5] Eichler, C., J. Legro, P.R. Barnes, "Experimental Determination of the Effects of Steep Front-Short Duration Surges on 25 kVA Pole Mounted Distribution Transformers," IEEE Transactions on Power Delivery, Vol. 4, No. 2, April 1989, pp. 1103-1109, in IEC TR 61000-1-3, "The effects of high-altitude EMP

(HEMP) on civil equipment and systems," June 2002.

Fact Versus Fiction on Energy Storage Systems

Schweitzer, Eric — Thu, 30 Apr 2009 21:45:00 GMT

Often, important emerging technologies get caught up in misconstrued facts and misunderstandings of capacities and roles in an already technology-driven and confusing world. An example of this can be found in a recent op-ed in the Washington Post, "Getting Real on Wind and Solar" by James Schlesinger and Robert Hirsch. It's great they included a reference to energy storage systems (ESS) as a necessary component of the smart grid architecture for renewable energy. And they're right that the wind doesn't always blow, the sun doesn't always shine -- so having a stockpile of energy that can be tapped into on demand, and especially during high demand or "peak demand" hours, is very important to ensuring adequate energy is always available. But their main thesis that renewable energy can't be pursued without adding coal-based utility resources or without using hydroelectric dams as energy storage tanks is wrong.

Using today's readily available technologies, ESS can run without the support of a hydroelectric dam or a coal based utility. The NEMA Energy Storage Council includes companies that produce flow cell batteries, flywheel generators, batteries (lithium ion, lead acid, lead carbon, sodium sulphur, zinc bromine, vanadium redox, etc), thermal systems, concentrated solar panels; even Plug-in Hybrid Electrical Vehicles that show great potential as a distributed mass ESS. The list goes on and on and it will continue to grow as existing and emerging technologies vie for the top spot. While stationary (flywheel, flow cells, etc.) ESS does require a larger footprint in terms of space requirements and can be used in some cases as "spinning reserves" for hydroelectric dams; their value must not be unappreciated or misrepresented. Both stationary and mobile ESS (Plug in Hybrid Electric Vehicles) provide a vastly untapped revolutionary resource with the ability to alleviate our present and rapidly growing energy crisis and ensure a future success towards building a "smart grid." ESS can provide solutions to current grid capacity issues, residential/ commercial/ industrial/ military back-up generation, load leveling, frequency response just to name a few."

It's important that NEMA continue to serve the role of advocate during these organizational periods where stakeholders grapple with the feat of learning where to go to for accurate and timely information.

Smart Grid Depends on Standards. . . Soon

Scolnik, Alvin — Mon, 02 Feb 2009 19:56:00 GMT

If you heard the term Smart Grid 12 months ago, you might have wondered what it meant. Now, the term is everywhere. Even President Obama referred to Smart Grid in his first address to the Nation after his inauguration. Newspapers, magazines, websites, blogs, domestic and international, are all discussing Smart Grid. Why? Because Smart Grid holds the promise of providing electricity to homes and businesses more efficiently, more reliably, and more securely. Smart Grid promises to eliminate blackouts, brownouts, sags and surges. Smart Grid goes hand in hand with use of renewables, and reduction of ozone depleting and global warming chemicals. And Smart Grid may very well help the long suffering energy consumer pick and choose from available services in order to better manage his/her exploding monthly electricity bill.

But, none of this is possible until the various stakeholders reach agreement on how power generation, transmission and distribution equipment will be integrated with communications and control devices and software to enable seamless and instantaneous interoperability within and between local and regional grids. The Energy Independence and Security Act of 2007 directed NIST to work with NEMA and other key stakeholders to develop a framework for identifying and coordinating the many Smart Grid standards produced by dozens of interest groups. The International Electrotechnical Commission (IEC) recently created a high-level strategy group to do the same thing for international standards.

Yes, Smart Grid standards are on the drawing board. But timing is critical and the work must get done quickly in order for consumers to see any benefits. NEMA stands ready to bring stakeholders together to write the standards that will make the electricity grid Smart. To quote a well known maker of athletic wear -- Just DO IT!!

Energy Storage Technology Is Vital For "Smart" Grid Efforts

Schweitzer, Eric — Wed, 21 Jan 2009 17:08:00 GMT

NEMA is taking the lead in making Smart Grid and Energy Storage technologies a reality. The NEMA Energy Storage Council (ESC) has held successful meetings where attendees have drafted a list of application categories that help define where Energy Storage (ES) and Distributed Generation (DG) technologies should play a role. The NEMA ESC consisting of manufacturer, utility and government representative stakeholders further established and tasked a NEMA ESC Technical Committee (Stationary and Mobile Subcommittee) to identify specific action items aimed at facilitating the promotion of ES/DG technology to commercial and non-commercial markets. The result of the NEMA ESC Technical Committee meeting January 15, 2009 was an agreement to present a proposal for an all encompassing ES/DG demonstration program to prove the criticality of ES/DG technologies to the Department of Energy. It was fully agreed and can not be understated here that without the complete integration of ES/DG technologies to our ailing National electricity grid there can be no realized “Smart Grid.” Through this proposed demonstration program ES/DG manufacturers aim to prove the essentiality of ES/DG technologies to Smart Grid functionality and to demonstrate to the Government and Federal Agencies that ES/ DG technology can drive increased grid reliability, further reduction of carbon emissions, advanced T/D/G (Transmission/ Distribution/ Generation) capability, islanding capability, renewable energy penetration, interconnection realization, voltage support for public transportation systems, remote area power system capability (RAPS), zero net energy building capability, energy security, economic studies/ cost benefit analyses, and where electrical standards are required. The NEMA ESC has asked the Government Relations Department at NEMA to immediately get the message to Capitol Hill, The Obama Administration, DOE, FERC, NERC and other governmental agencies that NEMA is leading an effort to ensure Smart Grid success in addition to facilitating Energy Storage tax incentives equivalent to those being awarded to renewable technologies such as wind, solar, and hydro. For more information please contact Eric Schweitzer, NEMA Technical Program Manager at Eric.Schweitzer@NEMA.org

Green Energy Storage is becoming Red Hot

caskeyj — Fri, 19 Dec 2008 15:40:00 GMT

According to a news release from S&C Electric Company "the concept of energy storage has become a practical reality. Utility companies are now installing energy storage systems on their distribution circuits to gain experience with these new distributed power resources, and determining how best to use them for both planned applications and contingency events."

So what makes these energy storage systems GREEN? First, these Distributed Energy Storage Systems (DESS) can be used to help utilities regulate voltage on the distribution system and improve energy efficiency. Second, the utility can use these systems to avoid starting large fossil-fuel based generators. Third, the utility can use these systems to provide temporary power to residential customers so that the homeowners will not need to start-up environmentally-unfriendly, inefficient back-up power sources. In short, distributed energy storage systems can help utilities manage their distribution systems, improve energy efficency and reduce emissions.

Distributed Energy Storage Systems can play a major role in the nation's Smart Grid. Smart Grid is a term used to decribe the national electric grid enhanced with improved monitoring, control and communication capabilities. In essence, Smart Grid adds modern day IT capabilities to the nation's electricity infrasturture. To learn more about Smart Grid, visit the National Electrical Manufacturers Association (NEMA) website or the websites of the U.S. Department of Energy (DOE) or the U.S. National Institute for Standards and Technology (NIST).

NEMA and "Net Zero Energy" High Performance Green Buildings

Moldoveanu, Andrei — Tue, 02 Dec 2008 18:01:00 GMT

In April 2008 the National Science and Technology Council (NSTC) of the Executive Office of the President of the United States held a Workshop on "Net Zero Energy" High Performance Green Buildings. The scope was to define the R&D activities that could decrease use of natural resources and improve indoor environments while reducing greenhouse gas emissions and other harmful pollutants from the building sector. NEMA participated in the workshop, and its suggestions for areas that need to be researched and developed to achieve the net-zero energy building goal were included in the final report.The specific items proposed were: (1) Integrate distributed generation and on-site renewable resources into the electrical power grid. (2) Develop energy storage technologies. NEMA has established a Smart Grid Advisory Panel, a High Performance Buildings Council, and an Energy Storage Council to support standardization work needed to implement the necessary infrastructure for this massive endeavor.

Potential Nanotechnology Breakthrough for Li-Ion Battery Safety

leibowitzm — Mon, 15 Sep 2008 18:29:00 GMT

I read a recent article, "Planar Energy Devices Plans to Produce PowerBlade Advanced Battery in U.S.", announcing a breakthrough in lithium-ion battery safety, showing promise in a new generation of battery technology that meets the power output demands of large energy storage systems while at the same time assures safe operation. As exciting as this development might be, international battery and energy storage stakeholders will need the confidence of safety regulators, environmental advocates and the general public if mass commercialization of this technology is to ever take hold. This confidence will grow through the recognition and adoption of IEC standards that have been developed within IEC Subcommittee 21A, Lithium-ion batteries, that verify their operational safety.

The next step for this new technology however, is the development of a method for determining the reliability and durability of the nanoscale-subassembly of the composite separator, which was the key to the safety breakthrough. IEC TC 113, Nanotechnology standardization for electrical and electronic products and systems, is the forum for this to take place. Standards drive the commercial landscape and whoever drives standards holds the commercial high ground for their products. U.S.-based stakeholders have an opportunity to lead the international nanotechnology community in the development of such a method through the U.S. National Committee Technical Advisory Group to IEC TC 113 (TC 113 TAG). The TAG, led by Technical Advisor Dr. Brent Segal, is responsible for the introduction of U.S-led standardization projects for nano-scale electrical and electronic products and subassemblies.

NEMA Staff attend DOE Smart Grid workshop

caskeyj — Mon, 18 Aug 2008 15:18:00 GMT

Two NEMA staff members, John Caskey from the Industry Operations and Eric Hsieh from Government Relations, participated in the Department of Energy’s Smart Grid Implementation Workshop. The objective of the workshop was to develop metrics for measuring progress toward the implementation of the Smart Grid. More than 140 experts from utilities, equipment manufacturers, state agencies, universities and national laboratories attended.

Teams of attendees worked to develop metrics for seven specific smart grid characteristics including:

Enable active participation by consumers
Accommodate all generation and storage options
Enable new products, services and markets
Provide power quality for the range of needs in a digital economy
Optimize asset utilization and operating efficiency
Anticipate and respond to system disturbances in a self-healing manner
Operate resiliency against physical and cyber attack and natural disasters

According to the summary report from the workshop, examples of potential metrics for the seven smart grid characteristics include:

Percentage of customers capable of receiving information from grid operators and the percentage of customers opting to make electrical use decisions based on that information
Percentage of distributed generation and storage devices that can controlled by the grid operator
Number of smart grid products for sale that have been certified for end-to-end interoperability
Percentage of grid assets (e.g. transmission and distribution equipment) that are monitored, controlled or automated

The next steps are to refine the metrics and develop methodologies for measuring progress toward smart grid implementation. The DOE will then use the metrics to define the research, development, demonstration, analysis and technology transfer activities it will undertake as authorized by Title XIII of the Energy Independence and Security Act of 2007. A fundamental conclusion of the workshop is that there is an urgent need to provide educational materials about Smart Grid that contains consistent definitions and concrete examples for state utility regulators, environmental groups and consumers.

NEMA Premium Efficiency Transformers Program Gets an International Rollout

Hsieh, Eric — Wed, 18 Jun 2008 13:31:00 GMT

Yesterday morning at their annual meeting in Toronto, EEI Executive Director Diane Munns announced the creation of a joint program between EEI and NEMA to provide and procure efficient distribution transformers ahead of the Department of Energy's 2010 mandate. With CEOs from Consolidated Edison, TECO, Duke, and Pepco present, Munns lauded the efforts of utilities and manufacturers to implement efficiency technologies that are feasible today. Losses from transformers account for approximately 3% of electricty produced nationwide. In a market where energy costs are only headed up, this program represents a sensible measure to squeeze more performance from our existing grid.

Transmission For Renewables: Part 2

Hsieh, Eric — Wed, 16 Apr 2008 21:19:00 GMT

This afternoon, the President spoke about climate change and tossed out a goodie to those who have been harping for years on the need to build transmission to connect renewables. It’s great to have recognition from the top validating efforts on the ground, which leads us to the next project in this quazi-series.

The Tehachapi Renewable Transmission Project consists of eleven segments that will connect anticipated wind farms to the Southern California Edison system. The Tehachapi segments are a combination of upgrades to existing facilities as well as new lines on new rights-of-way. The California Public Utilities Commission approved the line on March 15, 2007. FERC approved incentive rates for the project in on November 15, 2007. The rate adders have since been challenged by various petitioners, and FERC granted rehearing this past January. Stay tuned to this development.