Dirk Benyoucef

Smart Meter with non-intrusive load monitoring for use in Smart Homes

One feature of Smart Homes includes recording the consumption of electricity of appliances in the household. The recordings are conducted using Smart Meters. To demonstrate the usefulness of Smart Meters for the final customers, this paper identifies several benefits by presenting the research area non-intrusive appliance load monitoring (NALM). The purpose is to discuss the energy consumption of different appliances in detail in order to determine a means of reducing this consumption. The analysis focuses on the drawbacks of the appliances examined. Based on the results of the analysis, the approach to gathering data is described. With this approach we want to greatly simplify the NALM process. Finally the initial results obtained using this approach are discussed.

Linear block codes for frequency selective PLC channels with colored noise and multiple narrowband interference

Power line communication (PLC) uses the highly developed infrastructure of the electrical energy distribution network for data transmission. Measurements are showing that a broadband use of PLC channels is possible. So, PLC is of interest to future broadband communication systems. Such systems will be heterogeneous in several respects, for example relative to the used transmission channel but also relative to the complexity of the participant nodes. Wittneben and Kuhn (see block VTC 2002 - Spring) presented a new class of space-time block codes for radio channels. These codes meet the requirements of future communication systems. They are highly flexible and can be adapted to the particular requests of the transmission. In this paper a PLC application of these codes is investigated. They are used as a basis for a scalable and efficient PLC channel coding scheme. This shows that this class of codes can be used as a generic coding scheme for heterogeneous networks. Alternatively, the PLC application can be considered as an example of the usage of the codes on a frequency selective channel with coloured noise. The applied linear block code optimally uses the diversity of the frequency selective channels in combination with OFDM. This leads to significant gains in performance in case of very frequency selective channels; for barely frequency selective channels or for an AWGN channel the performance is slightly better or not affected respectively. These performance results are presented for measured PLC channels.

Odor-Sensing System to Support Social Participation of People Suffering from Incontinence.

This manuscript describes the design considerations, implementation, and laboratory validation of an odor sensing module whose purpose is to support people that suffer from incontinence. Because of the requirements expressed by the affected end-users the odor sensing unit is realized as a portable accessory that may be connected to any pre-existing smart device. We have opted for a low-cost, low-power consuming metal oxide based gas detection approach to highlight the viability of developing an inexpensive yet helpful odor recognition technology. The system consists of a hotplate employing, inkjet-printed p-type semiconducting layers of copper(II) oxide, and chromium titanium oxide. Both functional layers are characterized with respect to their gas-sensitive behavior towards humidity, ammonia, methylmercaptan, and dimethylsulfide and we demonstrate detection limits in the parts-per-billion range for the two latter gases. Employing a temperature variation scheme that reads out the layer’s resistivity in a steady-state, we use each sensor chip as a virtual array. With this setup, we demonstrate the feasibility of detecting odors associated with incontinence.

Planning of energy production and management of energy resources with Smart Meters

For efficient planning of energy supply a Smart Grid is needed. One feature of the Smart Grid includes recording the electricity consumption of individual households. The recordings are conducting using Smart Meters. To demonstrate the usefulness of Smart Meters for the final customers, the paper identifies several benefits by presenting the research area nonintrusive appliance load monitoring (NALM). The purpose is to discuss in detail the energy consumption of different appliances in order to determine a means of reducing this consumption. The analysis focuses on the drawbacks of the appliances examined. Based on the results of the analysis, the approach to gathering data is described. This approach is aimed at greatly simplifying the NALM. Finally, the initial results obtained using this approach are discussed.

Smart meter systems detection & classification using artificial neural networks

The goal of that paper is to show a possibility for the disaggregation of electrical appliances in the power profile of residential buildings. The advantage is that the measurement system is at a central point in the household. So the installation effort decrease. For the disaggregation of the appliances out of the load curve, an approach for the development of a system based on pattern recognition is presented. One method for the classification of appliances is to use Artificial Neural Network. This idea is the main part of that paper. It is shown a method, to classify one kind of appliances. At the end, the first results and a comparison with the famous approach, for the disaggregation of electrical appliances, from Hart is presented.

Smart meter systems measurements for the verification of the detection & classification algorithms

In this paper the Non-Intrusive Appliance Load Monitoring (NALM) will be described as a technique to improve the current smart meter systems. The development and verification of a measurement system is described. With that system it is possible to simulate and measure the energy consumption of appliances in residential buildings. These measurements are used to develop and verify the disaggregation algorithms for the event detection and the classification. A first event detection algorithm, based on the calculation of the difference values of the power signals is presented. A comparison with another algorithm is shown. The usefulness of that algorithm for the event detection is discussed at the end of the paper.

Test bench and quality measures for non-intrusive load monitoring algorithms

Non-intrusive load monitoring (NILM) is the process of detecting the operation of electrical appliances from the data provided by a smart meter. This information can be useful in many fields, e.g. energy consumption and cost analysis, load prediction, or even ambient assisted living. Many NILM algorithms have been developed in the past but a well-founded comparison was impossible. This is due to the fact that it is very hard to generate suitable data sets. In this paper we describe one way to achieve this with very low effort. Furthermore we define several numbers for judging on the quality of NILM algorithms allowing for an easier comparison. They are a basis for our future work with NILM systems.

A new cascade decoder for precoded OFDM with analog linear block codes

Space-time codes and OFDM represent a key technology for future broadband wireless communication systems. In this paper a class of space-time block codes according to Marc Kuhn (2002) in combination with OFDM, is used which can lead to intersymbol interference (ISI) due to an optimized diversity performance. Therefore ISI compensation is an important task of the decoding process of these codes. Several known ISI compensation methods can he applied for example MMSE equalization or parallel or serial ISI cancellation. In this publication a new scalable decoder that works according to the parallel ISI cancellation method is presented. This decoder bases on a cascade structure with two branches for each cascade stage. The sub decoders in each branch were calculated coupledly according to the MMSE criterion. The inputs of the cascade are the receiver symbols and an estimation of the transmitter symbols realized with a MMSK estimator. The prioritization of the branches is made through the a priori symbol error probability. This probability bases on the transmitter symbols estimation. By varying the number of the cascade stages or the block length the performance of the decoder can be scaled.

Frequency invariant transformation of periodic signals (FIT-PS) for signal representation in NILM

It is the aim of non-intrusive load monitoring (NILM) to determine the individual energy consumption of multiple devices on the basis of the total energy consumption. The energy consumption of a single device is measured at a central point without the need of individual measuring instruments on the devices themselves. We present a new method for signal separation, decomposition of the signal into individual states and feature extraction. Frequency invariant transformation of periodic signals (FIT-PS) is based on a signal diagram similar to the concept of trajectories [1]-[3] utilizing the periodicity of voltage and current, and their correlation. A major advantage of this approach is the dimensional expansion of the signal. Thereby smallest changes cif the current can be identified easily and the associated change of state can be detected. This approach breaks down the current signal into its individual periods using the voltage as a reference signal for the determination of trigger points. Thereby, the phase information between current and voltage is maintained and is inherently part of the new signal representation. The efficiency of the new signal representation and signal separation is demonstrated by the example of an event detection algorithm. For testing the BLUED dataset [4] was used reaching a sensitivity in event detection of 99.31%.

Smart Metering: Entwicklung eines intelligenten Stromzählers

Im Rahmen dieses Beitrags wird anhand des Forschungsprojekts SmartMetering: Disagreggation von Energieverbrauchern die Entwicklung eines intelligenten Stromzahlers als eingebettetes System diskutiert. Dabei wird der Fokus auf die notwendige Data Acquisition Card gelegt, welche die analogen Messwerte erfasst und uber einen AD-Wandler digitalisiert. Die Messdaten werden vom AD-Wandler kontinuierlich per SPI-Bus bereitgestellt und mussen zwischengespeichert werden. Fur diese Aufgabe wird ein FPGA mit angebundenem RAM eingesetzt, so dass die Daten anschliesend als Pakete uber die USB-Schnittstelle in Echtzeit in das Linux System ubertragen werden konnen.