With the rush towards energy efficiency there is a mark that has been repeatedly missed, being EMI or electromagnetic interference getting dumped on our power grid. Also known as “dirty electricity” , high-frequency voltage transients (HFVT) and harmonics . Common sources for this interference is as follows:
Things that cause arcing:
[Blenders, mixers, corded drills and power tools, Hair Dryers ( motors using brushes)], Welding Equipment, Arc Lamps such as spot lights, Loose connections on equipment and terminations (can be detected using thermal imaging or parabolic listening devices).
Powerline Communication Protocol:
Devices with this technology use a building’s existing power wiring in order to send data at a carrier frequency different than that of the base 50/60hz fundamental frequency in order to be distinguishable from the normal ac sign wave. It has it’s origins as far back as 1838 with Edward Davy’s design for a remote readable electric meter but didn’t begin widespread use until 1922 over high-tension lines with frequencies of 15 to 500 kHz for telemetry purposes, and this continues. Today’s applications involve high speed broadband internet as a way cost effective deployment over existing infrastructure.
https://www.sciencedirect.com/topics/engineering/power-line-communication
Common non-linear loads:
Light dimmer switches (Triac/Solid State),Televisions,Desktop computers and laptops,Video game systems, Cordless phone systems , SMART meters and appliances, Wi-Fi routers and modems, Battery charging devices for cell phones, tablets, LED Bulbs, Variable speed/brushless Motors ( washers, dryers, vacuum cleaners ), Solar power systems ( Non-Pure Sine Wave Inverters are the biggest culprit and commonly emit in the 20khz range on the lines and ground ), Telecommunications equipment, Variable speed Heat pumps ( central air and mini split as a function of blower or compressor motor inverters ), Fluorescent light bulbs and tubes (ballasts)…there’s a longgggg list of things here.
Example of a desktop computer…
HVFT
Harmonics
What is the impact of this noise?
Harmonics in power systems can have significant and far-reaching consequences, affecting both equipment and overall system performance. The consequences can be categorized into several areas:
Equipment Damage
- Capacitors: Blown fuses, reduced capacitor life
- Fuses/Breakers: False/spurious operations, damaged components
- Motors: Reduced motor life, inability to fully load motor
- Transformers: Increased copper losses, reduced capacity
- Electronic loads: Disoperation
System Performance
- Increased heat generation: Harmonics can cause excessive heating in equipment, leading to premature aging and failure.
- Resonance: Harmonics can create resonance in the system, amplifying their effects and causing equipment malfunction or failure.
- Voltage distortion: Harmonics can distort the voltage waveform, affecting the operation of sensitive equipment and causing power quality issues.
Power Quality
- Flicker: Rapidly changing loads can cause flicker, affecting lighting systems and potentially causing discomfort or disrupting operations.
- Inter-harmonics: Non-integer multiples of the fundamental frequency can cause additional distortion and interference.
Economic Consequences
- Increased costs: Harmonics can lead to premature equipment replacement, maintenance, and repair, resulting in significant economic losses.
- Downtime: Harmonics can cause equipment failures, leading to extended downtime and lost productivity.
- Has a HUGE impact on the switch over to digital AMI metering infrastructure.
- Increased Health Care Costs ( Scroll Down Further )
Static energy meter errors caused by conducted electromagnetic interference
Franciscus Bernardus Johannes Leferink – University of TWENTE
Published - 1 Mar 2017
When Certified Smart Meters Still Give Wildly Inaccurate Readings
DAVID THORPE – Energy Central -
May 19, 2017
A NIST Testbed for Examining the Accuracy of Smart Meters under High Harmonic Waveform Loads
May 2019 https://nvlpubs.nist.gov/nistpubs/ir/2019/NIST.IR.8248.pdf
Impact of Harmonic Current on Energy Meter Calibration
2010 NCSL International Workshop and Symposium
Steven Weinzierl, Radian Research, Inc
3852 Fortune Drive, Lafayette, IN, 47905,USA, (765) 449-5548, stevew@radianresearch.com
Energy Meter with Fast Cycling load
Health Sector Consequences
- Headaches, anxiety, depression, and suicide: Some individuals have attributed these symptoms to low-level exposure to electromagnetic fields (EMFs) at home.
- Fatigue, dizziness, headaches, problems with concentration and memory, and sleep disturbances: People who claim to be hypersensitive to EMFs report these symptoms as a result of exposure to dirty electricity.
- Cancer: Exposure to HFVT was associated with increased cancer risks.
- Diabetes: Studies have suggested a possible association between dirty electricity and diabetes.
- Asthma: Dirty electricity has been linked to asthma and other respiratory problems.
- Behavioral and learning problems in children: Exposure to dirty electricity has been associated with behavioral and learning difficulties in children.
- Physical, emotional, and cognitive health problems: Scientific evidence points to a connection between electrical energy and electromagnetic interference, leading to a wide range of health issues.
SITE LEVEL CONSIDDERATIONS FOR REMEDIATION OF EMI ON EXISTING INFRASTRUCTURE
Required inspections for Wiring Errors
1 ) - Before any corrective action is taken to lessen noise on existing or planned installations in both commercial and residential wiring, inspections should be carried out to ensure the premises are free from wiring errors ( separation of wires, improper bonding, grounds carrying current, shorts, reversed hots and neutrals, etc. While time consuming, this ensures the likelihood of generating larger problems with resonant noise and capacitive coupling issues within electrical and magnetic fields generated from such errors.
2 ) - Determination of the Noise Sources by Process of elimination
2.1 ) Thermal and physical inspection should be carried out for all wiring landing points to ensure proper torques of conductors. Loose connections cause noise and heat due to arcing.
2.2) Using a systematic process of elimination starting under no load conditions, loads are gradually added and subtracted with the AC waveform being monitored for indices of EMI interference. This can be accomplished using a spectrum analyzer, oscilloscope or residential EMI meter such as a
Greenwave EMI (Dirty Electricity) Meter - Greenwave Filters or Stetzerizer Stetzerizer Microsurge Meter | Stetzer Electric, Inc.
Triac dimmers for example should be eliminated and either replaced with sinewave dimmers, variacs, or reostats if dimming is an absolute requirement for the lighting applications. If dimming isn’t an absolute need, remove the dimmers. LED lamps should be replaced with low noise light engines or reverted to incandescent if no suitable low THD replacement is found. Passive/active filtration or isolation techniques can be employed to reduce or eliminate non-linear loading issues. Switch mode power supplies should be replaced with linear power supplies where applicable ( wall worts are a prime example) When the equipment causing the noise cannot be removed then such equipment must be either modified or isolated using noise reduction equipment (such as an isolation transformer) to address the generated noise from such installations.
3 ) - Noise Correcting equipment
3.1 – Isolation Transformers – Should be used on loads with exceptionally high THD output for total isolation ( Desktop computers, inverters for solar , heat pumps and variable speed motor drives, etc ) and sized accordingly so as the applied load does not saturate the transformers core. Avg, loading should be sized to be between 30-70% of rated capacity. Transformers are readily available in many sizes but note that toroidal types have the lowest stray magnetic fields and better efficiency.
3.2 – Capacitive Filtering – Typically cheaper than isolation transformers. Use of capacitors have to have special considerations that no wiring issues first exist prior to installation as magnetic fields can be amplified (see additional references). Specifications for the filter must match the frequency profile it is being used for removal. Improperly designed capacitive filters can cause harmonic resonance when the resonance frequency between transformers and capacitors approach the harmonic frequency being filtered effectively exacerbating harmonic noise by orders of magnitude. Properly designed harmonic filtration will eliminate the noise and improve power factor which is beneficial for both residential and commercial electrical overhead reduction. Consumer level capacitive filters are available in simple forms for common harmonic frequencies from a variety of sources. GreenWave and Stetzerizer being the most common and simplest having frequency response between 1.7khz-1mhz.
Greenwave Dirty Electricity Filter - Greenwave Filters
Stetzerizer Filter | Stetzer Electric, Inc.
3.3 – Specialized Filters – These filters are designed to filter a broader range or custom frequency ranges per your specification. You would need a spectrum analyzer to know exactly what you are trying to filter if you want to remove all noise above 50/60 hz from your lines. They will generally be far more expensive on par with residential sized isolation transformers.
https://www.onfilter.com/ac-emi-filters-af-series
https://www.newark.com/c/passive-components/emc-rfi-suppression?st=2+stage+filter
3.4 – Active Harmonic filters – These are very specialized equipment and not typically used in residential service as they are commonly considered a capital investment. They monitor the waveform on a power system and inject an opposite waveform in order to cancel out any harmonic above the fundamental frequency. In this regard they can handle a wide variety of variable conditions as they are not fixed to a particular frequency range.
EQUIPMENT MANUFACTURER STANDARDS
Manufactures of modern day equipment using inverters, switch mode power supplies, triac dimmers, etc have not been held accountable for the noise their products produce nor have tight regulations been put into place to ensure any device being installed does not produce excessive noise prior to installation for any application. As a result, our grid, commercial, and home electrical systems are at the worst saturation of noise it’s ever been since the first light bulb was turned on.
This oversight is costing us on multiple angles and the need to clamp down on our overall power quality is an ABSOLUTE must