Energy meters become smarter and deliver higher accuracy

With continuous technological advances, the latest energy meters have become more efficient and accurate in measurement, communication and controls

By Kartiki Negi

Thursday, October 30, 2014: An electronic energy meter (EEM) is used in residential, commercial and industrial applications to measure the amount of energy supplied or produced. One of the major advantages of EEMs is that, in non-linear loads, their metering is highly accurate and they are more rugged than conventional mechanical meters. Companies that use EEMs can benefit in three significant ways. EEMs reduce the possibilities of power theft and corruption on electricity distribution networks because of their inherent design and prepayment interfaces; they measure current in both phase and neutral lines, and calculate power consumption based on the larger of the two currents; and they improve the overall cost efficiency and quality of electricity distribution.

The Indian energy meter market is evolving continuously, with technology upgradation taking place at a very fast pace. New technologies are evolving on all fronts—in measurement, communication and controls.

There are different measuring nodes in power systems. These encompass generation, substation feeders, distribution transformers, industrial and commercial segments, and small commercial and residential segments. Each measuring node has its own requirements for measurement functionality and other associated features. Hence, a wide range of EEMs are available in the market, the most prominent of which are the electromagnetic, static and induction types of electromechanical meters. Among these, there are single-phase energy meters with mechanical displays, single-phase energy meters with LCD displays and anti-theft features, three-phase energy meters with LCD meters, high accuracy TRI vector meters with multifunction displays, etc.

What the market offers

Earlier, energy meters only measured the electricity consumed up to a certain extent, while communicating the data at the end of the month to the billing station. They did not have the intelligence to control the consumer load based on predefined parameters like over voltage/current, abnormal frequency, in cases of meter tampering or low credit, etc.

However, today, smart energy meters come with inbuilt technology that helps them to communicate on a real time basis with the central station. Any abnormal conditions in the meter are reported immediately, which reduces the response time of the station.

Genus Power Infrastructures Ltd recently launched smart energy meters that comply with DLMS/COSEM, an open communication protocol for interoperability among various vendors. These meters come with inbuilt communication facilities like GSM, GPRS, etc, and can be configured for pre-paid or post-paid billing, a load controller, for street lights and various other applications. The features include two-way communication, which enables the transfer of real time data to a central server as well as remote configuration, updating and controlling of the meter from a central station.

Smart energy meters provide different tariff plans to reduce the demand during peak hours, and eliminate the manual meter-reading costs and the errors associated with it. They also help consumers to monitor their hourly, daily, weekly and monthly consumption of power. With the Time of Use (TOU) function, consumers can optimise their electricity consumption and reduce their bills. Smart meters can be used at every level of the distribution network, be it a residence, commercial establishment or distribution transformer.

Vsquare Automation & Controls’ energy meters come with varied technical specifications like numerical motor protection relays, digital read-outs and LCD displays. Designed with precision and incorporating sophisticated technologies, these machines are suitable for critical applications in different industries. They are widely used in automatic power factor controller relays (APFC), maximum demand controllers (KVA/KW), intelligent load managers (KVA/KW), digital panel meters (DPM), motor protection relays, energy panel meters (KWH, VIF, VI-PF), ammeters and voltmeters (both digital and analogue), and in earth leakage and fault relays.

Mahesh Electrical Instruments offers energy meters that measure the DC energy consumed by a DC load or DC motors. These come with rechargeable nickel cadmium batteries (4×1.5V) that charge the mains to 230V AC. They offer current ranges of 2.5 – 5A DC, 5 – 10A DC and 10 – 20A DC, any one range.

Elmeasure has a unique 3-in-1 contactless prepaid energy meter, in which process parameters such as water or gas consumption can be integrated and monitored along with electrical parameters. The design is completely microcontroller based and provides an effective and reliable solution to service providers, who need to just install the meter.

The advanced microcontroller-based electronics inside the meter stores the number of units recharged and measures the energy consumed. When the purchased units are used up by the consumer, the meter disconnects the power supply until the next recharge. Available in single-phase and three-phase options, this user friendly meter comes with features such as advanced RF card technology and tamper-proof construction.

Sree Dhanam Automation’s electronic and digital energy meters are characterised by high accuracy and good performance at an affordable price. These meters have a long functional life and are highly efficient. The EEMs come with a self-power supply of 18 – 260V AC, VLN and an accuracy of V and A cl. 0,5; cl. 1 kWh (EN62053-21); and cl. B kWh (EN50470-3).

Buying tips

Several features and parameters need to be considered when selecting an energy meter. The meters should range between 2.5 to 10A, 5 to 20A, 5 to 30A, 10 to 40A and 10 to 60A. Customers must be very clear about the application the EEM is intended for; else, they will end up buying the wrong type of energy meter. Customers should also check some of the following critical parameters before zeroing in on any particular energy meter:

• Current carrying capacity

• Number of phases

• Critical electrical parameters

• Quality and reliability

• Whether microprocessors have been used or not

• Class of accuracy: For general applications, an accuracy class of 0.5 is appropriate. For precision measurement, the customer must buy meters with class of 0.2 accuracy, which should not deteriorate over a period of time.

• Renowned brand: The connection should be done by a licensed electrical contractor who has experience in installing such instruments.

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