Metering

General

With the advent of electronic metering, things in metering have become easier on some standards and harder on others. All solid-state meters (SSM), whether single phase or three phase, can be programmed for demand. Therefore, most utility companies bill for this service.

MetersSolid-state meters can also be programmed for Time of Use measurement and Interval type Recording (Mass Memory). The time of use meters can be programmed to look at peak times - for example 10:00 AM to 3:00 PM daily - and off peak the remainder of the times, with off peak also on the weekends. Also, some of these meters can be programmed Time of Use for winter and summer depending on the rates. Most of these meters have the ability to measure up to 4 different Time of Use periods and display these readings on the meter. The old induction meters of yesteryear did not have this ability.

Another benefit of the new solid-state meter is that instead of having to buy the appropriate meter to match the exact voltage, you now buy a variable voltage meter that can handle voltages from 120 volt to 600 volt. This greatly reduces the inventory you have to keep and increases meter reader efficiency.

The same solid-state meters can be bought with recording ability (Mass Memory) for very little, if any, price increase. When some of the first SSMs started appearing on the market, the manufacturers considered these meters "plug and play" and would charge for any additional equipment (pulses, mass memory). Now, when you order a new meter, these features come standard and you decide how you want to program, whether standard kWh-kW, TOU or Mass Memory.

Mass memory only refers to a meter that has the ability to store data in variable intervals. These meters can have intervals from five minutes up to one hour in length. Most utility companies measure peak demand on a 15-minute, 30-minute, or one-hour demand interval.

Interrogation Strategies

Interrogation of these meters can be made several different ways. They can either be read on site or remotely. On site is simply walking up and probing the meter by way of an optic communication device that is attached to a computer (laptop) or a field reader of sorts and extracting the interval-by-interval load information. On the front of the solid-state meters is the optic connection port. These meters also have the ability to store data, in some cases up to 12 months of 30-minute intervals.

Solid-state meters can also be remotely interrogated from the utility or energy user's facility. This can only be accomplished if the meters have a built -in modem or if they are programmed to communicate by way of RS-232 or 485. These options usually will come as an extra cost. Either a standard analog phone line or a cell phone works well to communicate with these devices and can provide unlimited access instead of visiting the premise for monthly, on-site interrogation.

Another remote interrogation method is Radio Frequency (RF) technology - around 900MHz - this can be wired or wireless technology. This equipment uses a packet technology with multiple routers in order to receive this information. Most utilities are looking for ways they can access this data in the most economical fashion. A good method of reading a large number of accounts remotely may be to consider using the public wide area network for data transmission. This method can provide a cost effective solution for data load profile type metering as well as providing power quality and even utility automation. There is also a 2-way paging technology (Skytel) that is considered to be a very economical Wan technology for this application.

Consolidating Meter Data

Consolidation of accounts and/or load aggregation can be accomplished by the above-mentioned methods. New software seems to surface every day that can perform this task with ease. Load aggregation will take numerous energy customers and add their load together for a defined period and arrive at a total demand and energy.

Additional Links

Energy Tracking
Energy1st

Links to Related Topics

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Understanding Demand