The Sound of Silence: ‘Silent Transformers’ to Help Consolidated Edison Meet New York City’s Ultrastrict Noise Ordinances

“Pure Tones” are a manmade air pollutant and illegal to produce!! The utilities and regulatory agencies play dumb and impart many are ignorant of this technical information. BUT! The engineers who implement these designs know fully well the impact this has to humans and wildlife.  “pure tone” are a public health hazard and now with the smart meter network turned on the noise is not localized to one transformer.  IT IS NOW A GLOBAL PUBLIC HEALTH HAZARD….Sandaura

The Sound of Silence: ‘Silent Transformers’ to Help Consolidated Edison Meet New York City’s Ultrastrict Noise Ordinances

By Dr. Ramsis Girgis, ABB Inc.

Silence is a source of great strength. Although these words were coined by the ancient Chinese philosopher Lao Tzu, they apply to modern transformers. These devices ensure our power supply, and it is important not to ignore the negative sides of their operation. Noise is a major issue.

Transformers exhibit vibrations while operating, which generate a characteristic hum classified as noise. This noise is characterized mainly by four pure tones, the frequencies of which are in the range of human speech. The noise causes irritation and discomfort, so it is important to ensure residential areas are unaffected by noise of nearby transformer installations.

Probably the strictest noise ordinance in the world is in New York City. To fulfill the restrictions, it is necessary to understand the total process of sound generation, transmission and radiation. Such knowledge has enabled ABB to design and build quiet transformers for customers throughout the world. Most recently, ABB delivered ultralow-noise power transformers, referred to in this article as “silent transformers,” to the Consolidated Edison (ConEd) utility in the Manhattan borough of New York City.

Sound Level Units

Sound-level limits typically are determined by the perception of the human ear to sound. For example, doubling the magnitude of the sound pressure is felt by the human ear as a small increase in sound level. The human ear is also 10 times more sensitive to a sound of 1,000-Hz frequency than it is to a sound of 100-Hz frequency. Sound, therefore, is measured in decibels (dB), and a decibel is 10 × Log10 (sound pressure). Sound levels typically are presented and specified in A-weighted decibels; dB(A), where the sound levels are attenuated according to their frequencies per an “A-filter,” which depicts the frequency response of the human ear.

1  Noise levels around a substation with two 40-MVA transformers

Industry standards, such as IEEE and IEC, specify how transformer noise is measured. Some customers, however, require reporting of the transformer’s total collective noise level in dB(A), while others require reporting of sound level of the transformer’s individual frequency components noise. Most customers require measurement of only the core and fan noise, but some require measuring the total noise level of the transformer, including noise generated from the load on the transformer, referred to as load noise.

Transformer Noise, Characteristics

Three sources of sound and noise exist in power transformers: core noise, load noise and cooling system noise.

Core noise is caused by the magnetostriction property of core steel. Magnetostriction is a term for the small, mechanical deformations of core laminations in response to the application of a magnetic field. The change in dimension is independent of the direction of the flux, and hence it occurs at twice the supply frequency. Because the magnetostriction property is nonlinear, however, higher frequency harmonics of an even order are introduced at higher flux densities. Therefore, core noise has components at multiples of 100 or 120 Hz (for 50-Hz and 60-Hz transformers, respectively). The relative magnitudes of the noise at these different frequency components depend on core material, core type and operating flux density.

Load noise mainly is generated by windings vibrations caused by the electromagnetic forces as a result of the interaction of load current and leakage flux produced by this current. Another source of load noise is tank vibrations caused by the magnetic-pull forces exerted by the leakage flux. The main frequency of this sound, therefore, is twice the supply frequency. The level of load noise is determined by load current, winding design and the type of tank shielding used.

Cooling system noise is generated by the operation of the cooling equipment, fans and pumps. This noise has a broad frequency spectrum with a peak at the blade passage frequency, the frequency at which the fan impeller blades pass some rigid disturbance in the air flow, and sometimes twice that frequency. Pumps also produce noise of a broad band nature and contribute to the total noise of the transformer.

Designing Low-noise Transformers

Today’s low-noise power transformers produce noise levels significantly lower than those built 20 or 30 years ago. Important contributors to achieving these low levels of transformer noise are: designing for low core noise, low load noise and low cooling system noise.

Designing for low core noise. In addition to using higher grades of magnetic orientation core steels with low magnetostriction and reducing the flux density in the core, core noise can be reduced by other measures, including:

1.) Designing transformer cores to provide a more uniform distribution of magnetic flux with a lower content of flux harmonics globally in the core and locally in the core joints. Detailed 2-D and 3-D magnetic field modeling optimize core designs to minimize core noise.
2.) Calculating vibrations. The core is held together by a clamping structure that provides uniform pressure on the core laminations while local deformations are avoided. ABB uses tools developed in-house to calculate the vibrations of the core considering modes of vibrations, as well as the complex forces exciting a three-phase transformer core.
3.) Avoiding excitation of core mechanical resonances. This necessitates accurately predetermining values of the different core resonance frequencies.
4.) Decoupling of core vibrations from the tank. New techniques reduce the transmissibility of the core vibrations to the tank and hence the resulting sound radiation. To get good results, it is necessary to consider carefully the dynamic properties of the core and tank. The vibration isolation elements must be designed properly.
5.) Avoiding noise increase caused by its high radiation efficiency or tank mechanical resonance. Acoustic simulations, verified by scale models and full-size experiments, provide the tools necessary to avoid tank resonances and reduce sound radiation.
6.) Using sound panels or sound enclosures covering parts of the tank or the entire tank.


Designing for low load noise. Winding type, winding arrangement, current density, tank shielding/shunts and tank design parameters significantly affect the magnitude of load noise. Extensive development has resulted in the following measures for load noise reduction:

  • Using winding designs, which generally results in lower magnitudes of leakage flux.
  • Avoiding winding mechanical resonance.
  • Improving tank shielding against leakage flux.
  • Damping treatment of the tank.
  • Improving tank design having lower sound radiation properties.
  • Creating sound enclosures covering the entire tank.


3  3-D modeling of vibrations of the tank of a three-phase transformer

Designing for low cooling system noise. Noise from cooling fans can be reduced by selecting low-speed fans or fans with sound-absorbing elements at the inlet and outlet. Other means include fan designs with improved noise performance. In cases where strict noise requirements apply, fan noise is eliminated by designing the transformer with radiators instead of fans. When cooling pumps are required, pumps with low-noise emission are adopted.

ConEd Transformers Design, Performance Requirements

To satisfy the New York City Noise Ordinance, ConEd’s electric equipment department revised its noise specifications for new power transformers, requiring ultralow-noise transformers with the following requirements:

  • 15- to 20-dB lower noise level than typical for these sizes of transformers.
  • Guaranteeing noise levels at 100 percent voltage combined with full load.
  • Guaranteeing noise levels at maximum overexcitation combined with 40 percent load.
  • Noise level limits are to be met for each frequency component.

The maximum allowable limits of the frequency spectrum of the total noise of the transformer (sum of no-load and load noise) for the most important frequency components of the transformer noise are shown in the fact box.

These levels correspond to a total noise level of about 59 dB(A) at 116 percent voltage and 100 percent current. The corresponding value for the total dB(A) at 100 percent voltage and 100 percent current is in the 54 dB(A) range. In comparison, typical low-noise transformers of this size would have noise levels in the 60- to 65-dB(A) range for no-load noise alone (core noise + cooling system noise). This demonstrates the magnitude of challenge the ConEd noise requirements represent.

The ConEd requirements impose other design restrictions:

  • Tight limits on weight, width and height to permit transportation in Manhattan.
  • Tight limits on transformer impedance variation across the range of the tap-changer.
  • Significant overload requirements (up to 200 percent).
  • Limits on temperatures of hotspots in the windings at different loads.

The designs requested by ConEd were for their standardized 65-megavolt ampere (MVA) and 93-MVA network transformers.

ConEd Transformer Solutions

Designing a transformer for such ultralow-noise levels while satisfying all the other limitations is possible only if the transformer manufacturer is capable of the following:

  • Accurate calculation of the noise level of the core vs. its flux density.
  • Accurate calculation of load noise.
  • Accurate calculation of resonance frequencies for the core, windings, tank plates and tank stiffeners.
  • Accurate calculation of frequency spectrum of core noise vs. flux density.
  • Effective means of reducing core and load noise for the different frequencies.
  • Proper transformer mounting techniques.
  • Accurate indoor measuring techniques of such low noise levels in the factory.

The more accurate all above calculations can be performed, the lower the margin of the resulting design would be, and the more feasible it becomes to satisfy the noise specifications.

A Consolidated Edison Success Story

As of fall 2003, ABB had the technology to design low-noise power transformers, but not to the levels or details required by the revised specifications for the ConEd ultralow-noise transformers. The next four years, the ABB technology development team worked on the eight noise-related technology areas. As a result of first-year progress, ConEd in 2004 awarded ABB the contract to produce the first ultralow-noise 93-MVA transformers. These three transformers were successfully tested and delivered in 2005. The first was equipped with a sound enclosure. The second and third had only sound panels attached to the tank walls.

After delivery, ConEd awarded ABB an order for two similar 65-MVA transformers. These transformers were designed using the low-noise technology available at the time. The transformers were produced with no external sound enclosure or sound panels. The second unit was designed with 15 percent less winding weight while testing 4 dB lower load noise than that of the first unit. Frequency components of the total of core and load noise of this transformer were between 2 and 5 dB lower than the ultralow levels specified by ConEd.

As a result, ConEd awarded five more 93- and 65-MVA transformers for delivery in 2008 and early 2009. These transformers upgraded the design of the earlier transformers with 10-20 percent less weight in core and windings while satisfying the ConEd requirements. These transformers passed all tests and were delivered to ConEd. The ultralow-noise transformer technology resulting from this development is being used to produce optimum designs for low-noise transformers for metropolitan areas around the world.

Dr. Ramsis Girgis of ABB Inc. leads the global core performance R&D activities in ABB’s power transformers business area. Reach him at

Welcome to the Matrix: Enslaved by Technology and the Internet of Things


Welcome to the Matrix: Enslaved by Technology and the Internet of Things

By John W. Whitehead
January 07, 2015

“There will come a time when it isn’t ‘They’re spying on me through my phone’ anymore. Eventually, it will be ‘My phone is spying on me.’” ― Philip K. Dick

If ever Americans sell their birthright, it will be for the promise of expediency and comfort delivered by way of blazingly fast Internet, cell phone signals that never drop a call, thermostats that keep us at the perfect temperature without our having to raise a finger, and entertainment that can be simultaneously streamed to our TVs, tablets and cell phones.

Likewise, if ever we find ourselves in bondage, we will have only ourselves to blame for having forged the chains through our own lassitude, laziness and abject reliance on internet-connected gadgets and gizmos that render us wholly irrelevant.

Indeed, while most of us are consumed with our selfies and trying to keep up with what our so-called friends are posting on Facebook, the megacorporation Google has been busily partnering with the National Security Agency (NSA), the Pentagon, and other governmental agencies to develop a new “human” species, so to speak.

In other words, Google—a neural network that approximates a global brain—is fusing with the human mind in a phenomenon that is called “singularity,” and they’ve hired transhumanist scientist Ray Kurzweil to do just that. Google will know the answer to your question before you have asked it, Kurzweil said. “It will have read every email you will ever have written, every document, every idle thought you’ve ever tapped into a search-engine box. It will know you better than your intimate partner does. Better, perhaps, than even yourself.”

But here’s the catch: the NSA and all other government agencies will also know you better than yourself. As William Binney, one of the highest-level whistleblowers to ever emerge from the NSA said, “The ultimate goal of the NSA is total population control.”

Science fiction, thus, has become fact.

We’re fast approaching Philip K. Dick’s vision of the future as depicted in the film Minority Report. There, police agencies apprehend criminals before they can commit a crime, driverless cars populate the highways, and a person’s biometrics are constantly scanned and used to track their movements, target them for advertising, and keep them under perpetual surveillance.

Cue the dawning of the Age of the Internet of Things, in which internet-connected “things” will monitor your home, your health and your habits in order to keep your pantry stocked, your utilities regulated and your life under control and relatively worry-free.

The key word here, however, is control.

In the not-too-distant future, “just about every device you have — and even products like chairs, that you don’t normally expect to see technology in — will be connected and talking to each other.”

By 2018, it is estimated there will be 112 million wearable devices such as smartwatches, keeping users connected it real time to their phones, emails, text messages and the Internet. By 2020, there will be 152 million cars connected to the Internet and 100 million Internet-connected bulbs and lamps. By 2022, there will be 1.1 billion smart meters installed in homes, reporting real-time usage to utility companies and other interested parties.

This “connected” industry—estimated to add more than $14 trillion to the economy by 2020—is about to be the next big thing in terms of societal transformations, right up there with the Industrial Revolution, a watershed moment in technology and culture.

Between driverless cars that completely lacking a steering wheel, accelerator, or brake pedal, and smart pills embedded with computer chips, sensors, cameras and robots, we are poised to outpace the imaginations of science fiction writers such as Philip K. Dick and Isaac Asimov. By the way, there is no such thing as a driverless car. Someone or something will be driving, but it won’t be you.

The 2015 Consumer Electronics Show in Las Vegas is a glittering showcase for such Internet-connected techno gadgets as smart light bulbs that discourage burglars by making your house look occupied, smart thermostats that regulate the temperature of your home based on your activities, and smart doorbells that let you see who is at your front door without leaving the comfort of your couch.

Nest, Google’s $3 billion acquisition, has been at the forefront of the “connected” industry, with such technologically savvy conveniences as a smart lock that tells your thermostat who is home, what temperatures they like, and when your home is unoccupied; a home phone service system that interacts with your connected devices to “learn when you come and go” and alert you if your kids don’t come home; and a sleep system that will monitor when you fall asleep, when you wake up, and keep the house noises and temperature in a sleep-conducive state.

The aim of these internet-connected devices, as Nest proclaims, is to make “your house a more thoughtful and conscious home.” For example, your car can signal ahead that you’re on your way home, while Hue lights can flash on and off to get your attention if Nest Protect senses something’s wrong. Your coffeemaker, relying on data from fitness and sleep sensors, will brew a stronger pot of coffee for you if you’ve had a restless night.

It’s not just our homes that are being reordered and reimagined in this connected age: it’s our workplaces, our health systems, our government and our very bodies that are being plugged into a matrix over which we have no real control.

Moreover, given the speed and trajectory at which these technologies are developing, it won’t be long before these devices are operating entirely independent of their human creators, which poses a whole new set of worries. As technology expert Nicholas Carr notes, “As soon as you allow robots, or software programs, to act freely in the world, they’re going to run up against ethically fraught situations and face hard choices that can’t be resolved through statistical models. That will be true of self-driving cars, self-flying drones, and battlefield robots, just as it’s already true, on a lesser scale, with automated vacuum cleaners and lawnmowers.”

For instance, just as the robotic vacuum, Roomba, “makes no distinction between a dust bunny and an insect,” weaponized drones—poised to take to the skies en masse this year—will be incapable of distinguishing between a fleeing criminal and someone merely jogging down a street. For that matter, how do you defend yourself against a robotic cop—such as the Atlas android being developed by the Pentagon—that has been programmed to respond to any perceived threat with violence?

Unfortunately, in our race to the future, we have failed to consider what such dependence on technology might mean for our humanity, not to mention our freedoms.

Ingestible or implantable chips are a good example of how unprepared we are, morally and otherwise, to navigate this uncharted terrain. Hailed as revolutionary for their ability to access, analyze and manipulate your body from the inside, these smart pills can remind you to take your medication, search for cancer, and even send an alert to your doctor warning of an impending heart attack.

Sure, the technology could save lives, but is that all we need to know? Have we done our due diligence in asking all the questions that need to be asked before unleashing such awesome technology on an unsuspecting populace?

For example, asks Washington Post reporter Ariana Eunjung Cha:

What kind of warnings should users receive about the risks of implanting chip technology inside a body, for instance? How will patients be assured that the technology won’t be used to compel them to take medications they don’t really want to take? Could law enforcement obtain data that would reveal which individuals abuse drugs or sell them on the black market? Could what started as a voluntary experiment be turned into a compulsory government identification program that could erode civil liberties?

Let me put it another way. If you were shocked by Edward Snowden’s revelations about how NSA agents have used surveillance to spy on Americans’ phone calls, emails and text messages, can you imagine what unscrupulous government agents could do with access to your internet-connected car, home and medications? Imagine what a SWAT team could do with the ability to access, monitor and control your internet-connected home—locking you in, turning off the lights, activating alarms, etc.

Thus far, the public response to concerns about government surveillance has amounted to a collective shrug. After all, who cares if the government can track your whereabouts on your GPS-enabled device so long as it helps you find the fastest route from Point A to Point B? Who cares if the NSA is listening in on your phone calls and downloading your emails so long as you can get your phone calls and emails on the go and get lightning fast Internet on the fly? Who cares if the government can monitor your activities in your home by tapping into your internet-connected devices—thermostat, water, lights—so long as you can control those things with the flick of a finger, whether you’re across the house or across the country?

As for those still reeling from a year of police shootings of unarmed citizens, SWAT team raids, and community uprisings, the menace of government surveillance can’t begin to compare to bullet-riddled bodies, devastated survivors and traumatized children. However, both approaches are just as lethal to our freedoms if left unchecked.

Control is the key here. As I make clear in my book A Government of Wolves: The Emerging American Police State, total control over every aspect of our lives, right down to our inner thoughts, is the objective of any totalitarian regime.

George Orwell understood this. His masterpiece, 1984, portrays a global society of total control in which people are not allowed to have thoughts that in any way disagree with the corporate state. There is no personal freedom, and advanced technology has become the driving force behind a surveillance-driven society. Snitches and cameras are everywhere. And people are subject to the Thought Police, who deal with anyone guilty of thought crimes. The government, or “Party,” is headed by Big Brother, who appears on posters everywhere with the words: “Big Brother is watching you.”

Make no mistake: the Internet of Things is just Big Brother in a more appealing disguise.

Even so, I’m not suggesting we all become Luddites. However, we need to be aware of how quickly a helpful device that makes our lives easier can become a harmful weapon that enslaves us.

This was the underlying lesson of The Matrix, the Wachowski brothers’ futuristic thriller about human beings enslaved by autonomous technological beings that call the shots. As Morpheus, one of the characters in The Matrix, explains:

The Matrix is everywhere. It is all around us. Even now, in this very room. You can see it when you look out your window or when you turn on your television. You can feel it when you go to work… when you go to church… when you pay your taxes. It is the world that has been pulled over your eyes to blind you from the truth.

“What truth?” asks Neo.

Morpheus leans in closer to Neo: “That you are a slave, Neo. Like everyone else you were born into bondage. Born into a prison that you cannot smell or taste or touch. A prison for your mind.”


WC: 1894