Chicago - Worst power grid

[dgale]

Chicago Is Worst Area in the US for 'Distorted' Power Supplies

Problems plaguing power supplies to more than 5 million US households threaten to reduce efficiency and damage home appliances, with Chicago the worst-affected area.

financialpost.com

 

[Rumpole]

Chicago Is Worst Area in the US for 'Distorted' Power Supplies

Problems plaguing power supplies to more than 5 million US households threaten to reduce efficiency and damage home appliances, with Chicago the worst-affected area.

financialpost.com

From the article they say that "Whisker Labs will start alerting customers that have installed the company’s home sensor devices about bad harmonics starting this week, so that households inform local utilities about potential problems. " Data is collected with the Ting monitor that Whisker provides free of charge through some insurance companies.

 

[microstrip]

Chicago Is Worst Area in the US for 'Distorted' Power Supplies

Problems plaguing power supplies to more than 5 million US households threaten to reduce efficiency and damage home appliances, with Chicago the worst-affected area.

financialpost.com

Unfortunately, as most articles of this kind, no technical numbers are given about this power problem - just vague information. But 8% distortion seems a high threshold. The usual thumb rules refer to 5%, precision instrumentation literature advise on having less than 3%. My house mains distortion is typically less than 1.5% .

 

[wil]

Would be curious if it it gives info on the different harmonics to just THD?

 

[Rumpole]

Would be curious if it it gives info on the different harmonics to just THD?

The white paper goes into much more detail. Check out the figures in the section quoted below.

"Several sensors were enabled with waveform recording to better understand the harmonic data composition. Figure 25 shows the waveforms from several of the sensors overlapped. The dashed line represents a perfect 60Hz sine wave with the other lines showing the readings from multiple sensors which show large distortions to the normal sine wave. A Fast Fourier Transform (FFT) of the waveforms had elevated levels of harmonic spectra, particularly below the 13th harmonic. Figure 26 shows the FFT for one of the waveforms above. Most power systems have naturally occurring odd harmonics (3rd, 5th, and 7th). However, these values were elevated during the storm. In addition, most power systems do not typically have even harmonics. The 4th, 6th, and 8th harmonics were also elevated during the storm.

 

[Rumpole]

Unfortunately, as most articles of this kind, no technical numbers are given about this power problem - just vague information. But 8% distortion seems a high threshold. The usual thumb rules refer to 5%, precision instrumentation literature advise on having less than 3%. My house mains distortion is typically less than 1.5% .

How are you measuring distortion in your house mains? The white paper that I linked to above has a lot more detail, including maps. I'm in a 0-5% THD area, but I'd like to get a more precise estimate. I should be able to get it from my Ting monitor, but they are not reporting THD numbers on the monitor. The Ting app shows voltage and high frequency noise, but not %THD.

 

[microstrip]

How are you measuring distortion in your house mains? The white paper that I linked to above has a lot more detail, including maps. I'm in a 0-5% THD area, but I'd like to get a more precise estimate. I should be able to get it from my Ting monitor, but they are not reporting THD numbers on the monitor. The Ting app shows voltage and high frequency noise, but not %THD.

Using an audio spectrometer to measure the 50 Hz distortion - I get the THD figure and the spectra. Surely the amplitude must be decreased linearly and the system must be floating and battery operated. IMO just a couple of integral numbers is not enough to diagnose mains for high-end purpose.
How does the Ting weight HF noise?

 

[wil]

Using an audio spectrometer to measure the 50 Hz distortion - I get the THD figure and the spectra. Surely the amplitude must be decreased linearly and the system must be floating and battery operated. IMO just a couple of integral numbers is not enough to diagnose mains for high-end purpose.
How does the Ting weight HF noise?

I’d be curious to see more details showing how you go about your measurements?

 

[microstrip]

I’d be curious to see more details showing how you go about your measurements?

Unfortunately, playing with mains the way I do can become a very dangerous activity. The system can be very simple, but needs some care in specific aspects - a simple wire mistake can destroy the computer running the software. Shock hazards are really dangerous!

The spectra is measured using the demo version of Spectraplus using an USB sound card.