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Energy and Water Monitoring System for Smart Metering and Consumer Awareness
1  Department of Electronics Engineering, Fiji National University, Fiji.


Smart meter facilitates real-time communication between the customer and the utility company offering various advantages to both the suppliers and the consumers. Problems such as meter reading, information on energy and water usage, demand requirements, varying tariff, billing and theft can be solved through smart metering. This paper presents the design and implementation of an automatic electricity and water meter system. The system consists of the smart meter comprising a GSM board, Arduino microcontroller, a clamp current sensor together with a water flow sensor for measuring the amount of electricity and water consumed.  An in-house display which communicates with the smart meter via a RF link offers the consumers access to real-time data of their consumption.  The in-house display system, which requires authentication to communicate with the smart meter, also offers the users to set usage limits with short message service (SMS) alerts, and turn on/off the supply of electricity or water. The usage details are also sent to the suppliers via a SMS for billing purpose. The supplier also has access to the smart meter system, as they can set usage limits or cut off supply in cases such as bills not being paid.

Keywords: automation; data acquisition; smart meter; SMS; wireless communication
Comments on this paper
Guillermo Robles
Power measurements
I'd like to know how you calculate the consumed energy without acquiring a voltage signal. Do you supose that the rms voltage is constant?

What is the sampling frequency of the current?

In non-linear loads the current would have an important total harmonic distorsion. How do you deal with harmonics, reactive power and power factor?
Alberto Vallan
As a reader, I think that the proposed system is designed to provide just a rough measurement of the active electrical power but it has a low cost and it does not require an electrical connection to the mains. The paper claims that the system has been calibrated at constant power factor and I suppose that the voltage amplitude is assumed as a constant too. As a consequence the overall power uncertainty considering the sensor uncertainty (I suppose 5% but the sensor datasheet only provides the sensor linearity and nothing is said about then accuracy) and the voltage changes (10%) is in the order of 15% (deterministic uncertainty model). Given this large uncertainty, the distortion and changes of the power factors can be neglected in most practical cases.

Guillermo Robles
Well, I have to disagree... Most electronic equipment such as laptop computers, gaming consoles, smart TV, etc. have a total harmonic distorsion factor so large that the power factor drops to values below 0.6. My interest in this paper was precisely, because I supervised a BSc. thesis where an arduino acquired voltage and current signals to measure the power and power factor of different appliances. We had to overcome some issues with the sampling frequency and data transfer to the storage SD card.
Shiu Kumar
In this paper, a constant voltage and power factor has been considered as is done by the electricity providers in the authors county. Tests are carried out at different loads to measure the power factor and average (which is usually around 0.85) is used. The system is designed for residential users hence constant pf is not an issue. the sampling frequency is 50 Hz.