Design Article
Enabling next gen smart utility meters
Milen Stefanov, Texas Instruments Inc.
10/2/2012 11:24 AM EDT
2. Architecture of a smart gas meter with wM-Bus
The main buildings blocks in a smart meter fully based on electronic components include:
• sensor(s) for the metrology part
• ultra-low-power MCU to process the sensor data and calculate the consumption
• communications system
• a power supply system
In today’s gas meters, the sensing portion (Figure 4) reports the flow throughput (often thru a Reed switch) along with exact gas pressure and temperature measurements. The main MCU block processes the sensor data and adjusts the gas flow volume to a normalized quantity, which is required for customer billing.
Normally, there is also a motor valve that can also be controlled remotely (e.g. over the wM-Bus link) and in some countries a pre-payment option is required as well.
Click on image to enlarge.
The main buildings blocks in a smart meter fully based on electronic components include:
• sensor(s) for the metrology part
• ultra-low-power MCU to process the sensor data and calculate the consumption
• communications system
• a power supply system
In today’s gas meters, the sensing portion (Figure 4) reports the flow throughput (often thru a Reed switch) along with exact gas pressure and temperature measurements. The main MCU block processes the sensor data and adjusts the gas flow volume to a normalized quantity, which is required for customer billing.
Normally, there is also a motor valve that can also be controlled remotely (e.g. over the wM-Bus link) and in some countries a pre-payment option is required as well.
Click on image to enlarge.
Figure 4: Smart Gas meter (wM-Bus as a Sub-1GHz RF link at 169MHz or 868MHz)
Click on image to enlarge
Click on image to enlarge
For water and heat meters, the most common sensors used today are detecting the flow thru measuring rotation speed and direction.
A heat meter is a water meter with additional precision temperature measurements for capturing the temperature of forward and backward flow. Adding an RF subsystem (such as a sub-1GHz or 2.4GHz communications module) is the way to make heat and water meters “smart”.
It’s important to remember that water, heat and gas meters are all powered thru batteries, meaning ultra-low-power consumption is a major consideration. Since these three types of meters have a limited space for the battery, a dedicated power solution for optimizing battery life becomes mandatory.
A heat meter is a water meter with additional precision temperature measurements for capturing the temperature of forward and backward flow. Adding an RF subsystem (such as a sub-1GHz or 2.4GHz communications module) is the way to make heat and water meters “smart”.
It’s important to remember that water, heat and gas meters are all powered thru batteries, meaning ultra-low-power consumption is a major consideration. Since these three types of meters have a limited space for the battery, a dedicated power solution for optimizing battery life becomes mandatory.
|
|
|
|
|
Navigate to related information
WKetel
10/3/2012 9:18 PM EDT
I see a whole lot of discussion about the technology for the communication with the smart meters but only a small amount about how this is going to save enough energy to be worth the effort. Of course, the very first use will be to raise prices a lot just when everybody wants power the most. We all know that is the primary goal of the two way system. The other goal is to eliminate the expense of manual meter reading, which will reduce the utilities costs quite a bit, but will not reduce our price for power at all.
The way to eliminate all of the privacy concerns is to keep the specific minute-by-minute consumption data in the meters, and to just totalize the product of KWH and the rate at the time of consumption. Then the utility could poll the meters to determine the charge for that month's power. No customer information except for the total charge would ever need to be sent out, just as in the past when meters were manually read. The utility has no need of individual household consumption at any particular time, only block by block, or subdivision by subdivision. The assertion that they need to know the individual rate of use at any particular instant is not valid.
Sign in to Reply
GPBobby
1/18/2013 11:06 PM EST
Data is only useful to the extent that it can alter some outcome, in this case, a customer's use of electricity. Almost no electrical customer even knows that their new smart meter is capable of turning off their power. The above article states, "to enable utilities to ease peak power demand..." where ease should be read as: a) a total disconnect; b) a rolling brown out; c) by interfacing with your own personal in home network to turn off selective appliances such as A/C, dryers, heat pumps or any other device which has built in communication capability.
I can see a small business in modifying newer appliances (if possible) to make sure they cannot communicate. The polite way to modify power consumption is to let the consumer know (by checking an Internet site at their convenience) their current charge per kWh. Then let them decide what devices to turn off.
Sign in to Reply
pekon_
1/24/2013 11:42 PM EST
But if this was so lucrative, then why did google retired their power-meter service ?
http://www.google.com/powermeter/about/
Its just that there isn't enough eco-system built around to manage|optimize energy. And also its usage is expensive.
Many companies have smart-metering products from long, but lack of government urgency, and tough norms are also pulling this market low.
[pekon]
Sign in to Reply
GermanInTI
2/27/2013 4:46 PM EST
Not only MCU but also memory is a key factor for smart utility meters. TI is somehow leading the MCU part but not the memory, suprisingly even having a great technology called FRAM in Texas. FRAM makes the meter design extremely simple and flexible. Fujitsu and Ramtron leads the memory market for smart meters with FRAM. TI wake up...
Sign in to Reply