EEVblog #1283- What is Mains Ripple Injection?

What is Mains Ripple Injection and control?
A mystery bunker item teardown turned out to be a very interesting and obscure bit of test kit.

#DumpsterDiving #Teardown

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[Moonbase]

This has been used in Germany for decades, mainly for load balancing and switching on/off night storage heating systems ("Nachtspeicheröfen"), in conjunction with two-tariff electricity meters. In the late 1960s and early 1970s, they did lots of experimentation with this technique, like even alarming the fire department, or remotely switching off the mains for customers that didn’t pay. As far as I know, they used a lot of different protocols (Decabit was one of them), the local electricity board decided which was used. I believe this is still now used to limit power injection from third parties into the network, i.e. from solar or wind parks (everything that could inject more than 30 kW).

The German name for this is "Rundsteuertechnik", and it uses frequencies between 167Hz and 2kHz, with an amplitude of 1–8% of the nominal mains voltage (limited to max. 9%).

The Zellweger company (now part of the Swiss Ascom holding) developed the Decabit protocol in the 1960s. It has a start pulse "SI" plus 10 (thus "deca") pulses of 600ms each, so each command is 6.6s in length. Pulses are always followed by a pause, so a 5-of-10 combinations are possible. Now for n=10, m=5, n! / ((n - m)! * m!) = 252. Since commands are always "double commands" (for on/off, signified by a "+" or "-"), effectively 126 double-commands can be sent using Decabit. This is the reason why your device flashed "error" for some codes. Codes 0..126 should be valid for Decabit, "+" for "on" and "-" for "off".

Let’s take the Decabit command "011+", which would be "11010101010" (SI+1.I+2.I .. +10.I). The corresponding "off" command "011-" should be "10101010101", if I remember correctly. It has the pulses inverted, only I can’t quite remember if SI and the pause pulses had to be inverted, too. I _seem_ to remember SI stayed a "1" but all 10 pulses had to be inverted.

Interesting find!

[steverobbins]

I think those wires were left over from some troubleshooting session that was interrupted. The wires probably went to a bench power supply or multimeter. I guess they intended to come back to it, later so they left the wires in.

[EndstyleGG]

In my country Slovenia, my house had a I guess a similar type of injector, right next to the power meter, and apparantly it injected the switchover signal to the entire street. Of course since It was in our house and my grandfather was a electritian, he wired up a switch to the boiler and to the injector, where when you turned on the boiler, it would switch over to the cheaper electricity. It worked flawlessly until someone from the street complained that they were paying too little (how stupid can you be to complain about that) and the electric company showed up, saw what was going on and yeah you can imagine what followed. Anyway that happened some 20-30 years ago, well before I was born.

[ElmerFuddGun]

For future reference guys, don't list what DIP switches to turn on like this 1:13. Show the individual switches like 00001010 or even - - - - 1 - 1 -. It is so much quicker and easier and you can see *patterns* easily.

[dglcomputers]

In Britain it is done by a signal sent over the BBC R4 LW network on 192kHz, this frequency being able to be picked up in most of the UK from it's 3 main transmitters at Droitwich (main), Burghead and Westerglen (I would have thought that the two aforementioned Scottish relays would relay this information as well). There are/were? also a few small relays as well.
This service will run until the R4 LW transmitter at Droitwich uses up it's last spare transmitting valve as the BBC won't either have new valves made or the transmitters replaced.
In Britain the only real users of this system are people who have to use electric night storage heaters for one reason or another, as even with the off-peak rate gas is still cheaper.

[bjornroesbeke]

Rodalco2007 has a couple of videos showing the full size version of this device working.

[elguinolo]

Next one : mains botox injection, to get rid of ripples.

[matthewmaxwell-burton]

In France this is still used, although now it's the meter which receives the signal and activates a relay and switches the tarif. Before the newer meters came in you had a little box on the fuse board that connected to a relay controlling the hot water tank. I think it's in the 190 Hz range superimposed over 50 Hz. They also have other frequencies that can, depending on the contract, vary multiple tarifs or activate relays for load control.
I remember once when I was in a Rte (French transmission operator) sub station and working on an interface between the distributor (ENEDIS) and Rte. The signal generator kicked in and sounded like a fog horn, made me jump a meter. You could hear the transformer hum louder and all the ventilation kicked in. Basically every one started heating water.

[CrazyHamSales]

I remember when it used to be a thing here in the US. Power companies used to push it as demand switching and generally things like your electric tank style hot water heater would be put on a box with a relay in it, or some cases they used it to control the power to the outside unit for central air conditioning, etc. Then if there was a high demand event, like a super hot day and everyone is cranking the AC they could issue a command to shut off demand appliances to help the grid from overload. I don't see these anymore or hear it mentioned at all. The power companies used to do it here as an incentive, if you let them put it on your appliances they would give you a reduced cost or annual kickback. The bad thing i do remember is when they discontinued the program where i live, just about everyone had it on their hot water heater because there was a large push to save money by allowing it back in the day. It was a small box next to the breaker panel with three LED's in a small window on the front door, there was a green for operating, a green for appliance power on, and a red for appliance power off. What happened when they abandoned the system was they issued one final command to tell all the demand units to turn ON and stay on. So every one of these boxes were defaulted to just sitting there powering a relay inside that was turned on 24/7. So they were just wasting power, albeit a small amount, to run the board inside and keep that relay on all the time. The problem was they wired them so the appliance was on the NO terminal, so they had to be commanded to switch the relay ON or in the case of a power outage when the box reset it would turn the relay back on, i remember the box even had a label on it that said if the appliance wouldn't come on and there was not a demand event or if the appliance was needed during a demand event to power cycle the box, and it would default the relay back to on. The problem was after years of sitting idle the relay's started failing and dropping out and everyone was coming home to either no hot water or no AC at some point. Countless numbers of these were removed by local electricians as the local power municipality refused to take responsibility for they abandoned installs, and since people didn't want to pay an electrician most would open them up find the wires going to the hot water heater or whatever appliance and remove the two line wires from the relay and connect them with a wire nut and leave the box in place or take the output wire and put it on the input wire screw terminal to connect them leaving the box still powered and still consuming power via its transformer on the PCB inside, until eventually the units completely failed and died or in some cases even caught fire. Most people however were smart enough to remove both the line wires completely from the relay and leave the wire to the power supply on the PCB out of the wire nut, it had two wires on the supply side, the one from the breaker supplying the appliance one to a short jumper that went to the PCB to power it and people though it just needed to be there but some would remove power to the box and just leave it there as a junction box for the water heater for eternity! I have replaced water heaters where the box was still there, some even still powered with their LED's lit 20+ years since they were last in use. Most have been removed or just bypassed and left to collect dust these days, but they are a relic you still find in some basements near the breaker panel or water heater.

[coilsmoke]

Back in the 80's, the power lines in my old neighborhood made a buzzy sound around top of each hour at night. I think ballasts in street lights may have resonated with some kind of signal imposed on the mains. I thought I might hear something related to that someday...THANX !

[MyAvitech]

The shenanigans that can be had with such a device.

[djshex]

Here in Brisbane I can hear the signal through the ceiling fan at night. It is sent at around 20min intervals and lasts for 15 sec.

[jakubladman]

Here in the Czech republic (and also years ago in the former Czechoslovakia) it's called HDO, the czech abbreviation for Mass Remote Control. It is used not only to switch on or off the water heaters and other heat accumulation devices, but also to command the energy meters to switch between high and low tariff, also in places where the heaters are independent of it. As a teenager I added a LED indicator next to the washing machine for my mom let she know the right time to start the washing.

[jcobnl]

In The Netherlands we still have a control signal thing. It's called ToonFrequent (Tone Frequency) This system injects 492 Hz on the 50 Hz in the grid at serval intervals and controls the day/night tariff, public lights, highway lights, de-icing (only at very low temperatures), low/high tide (very important, because, yeah, Netherlands...), and some more stuff i haven't figured out yet. The old TF-receivers are well engineered electromechanical devices, with a synchonous motor and gear system and a discriminator (to filter the signal and sending a pulse to the motor). If you are interested, i can send you some of those devices.

[LaserFur]

I helped develop the turtle power line carrier system. It was a PLC system that as the record for the longest distance sent over a power line. At one point there was a meter in the outback of Australia sending meter readings to a transmission substation 200 miles away.

[kamaromike]

Are you telling me this sucker's nuclear?
No... it's electrical but I need the 1.21 Decabits to get the water heater started.

[christatler]

This method of remote switching of consumer devices by power companies has been around for a very long time. Modern Zellweger relays are all electronic, but back in earlier times, the actual relay coil was tuned for resonance at the frequency of the ripple. It would ignore the 50Hz mains frequency and react to the ripple when it was present.

[scrubberfred]

Wow what a blast from the past back years ago I worked for Seqeb which became Energex and I used to use one of those regularly in the late 90s. They were a key tool and that unit would have been set up to put out just above a 2 volt signal which was used to test the relays. We also used to use a pen recorder to measure to voltage levels of the ripple if a relay was testing fine but not switching. Thanks for bringing back some good memories.

[carlwedekind]

I used to work in a steel mill in Watervliet, NY that had three carbon arc furnaces for melting scrap steel. In the control room for each furnace there was a set of colored lamps, red, yellow, and green. In the summer, if the yellow or red lamp came on, the operator was to turn down the furnace to some specific power level. In the rest of the plant there was a siren that when it went off, we had 30 minutes to finish a process and then shut down the machinery. I believe we were given favorable electric rates and in turn, were allowed to be used for load shedding. I wonder if a similar method was used to send commands to our plant.

[norbert.kiszka]

When street lights rapidly turns on and off during the day, then You know: Dave founds something in the dumpster :D