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Craiova, Romania

Purcaru I.,VIG IMPEX | Purcaru D.,University of Craiova
Solid State Phenomena | Year: 2010

This paper presents a practical approach for a distributed data acquisition system organized on several levels, with functions distributed in functional nodes. A field bus allows the communication between all programmable electronic modules for data acquisition (first level) and the process server (second level); the last one is a data processing and monitoring equipment which also represents the process server in a computer network with many clients. The electronic equipment for monitoring and recording analog and digital inputs (i.e. a functional node from the first level of the distributed data acquisition system) is described in detail. This equipment is organized around the PC/104 central unit and performs four main functions: acquisition, configuration, local monitoring and communication. The experimental results, corresponding to the Server application, are also presented and discussed in this paper. © (2010) Trans Tech Publications. Source

Purcaru D.,University of Craiova | Purcaru A.,VIG IMPEX
Applied Mechanics and Materials | Year: 2013

The interface presented in this paper performs a synchronized sampling of all eight common-mode or differential analog inputs with a high sampling rate. This is a low cost interface, entirely controlled by the PC104 CPU. The paper is focused on design and operation aspects of the synchronized analog-to-digital conversion module. This interface is recommended for high speed data acquisition systems and finds its utility in energetic systems, for monitoring the power quality and for recording different specific transient events. Some programmable electronic modules which perform analog and digital signal acquisition in energetic systems already contain a PC104 interface with synchronized sampling of analog inputs; some experimental results are also presented in this paper. © (2013) Trans Tech Publications, Switzerland. Source

Purcaru D.-M.,University of Craiova | Purcaru I.,VIG IMPEX | Popescu D.,University of Craiova
Proceedings of the 2015 16th International Carpathian Control Conference, ICCC 2015 | Year: 2015

Some electronic modules perform the monitoring and recording of electrical events in power plants. Such equipment is based on signals provided by transducers that measure the process parameters. For example, PC-08/104 Process Control is an equipment which performs monitoring and recording of specific parameters when transient electrical events occur, for the post-failure analysis and diagnosis. This programmable digital equipment is versatile and can be connected to an IBM compatible PC or process server. The results obtained in hydropower plants in Romania - where PC-08/104 equipment runs for more years - confirm its utility and robustness. The paper is focused on the results obtained in monitoring and recording more specific parameters of transient electrical events using PC-08/104 digital equipment in several hydropower plants. The analyzed results are based on the processing of analog and digital signal samples acquired at successive moments. Eight analog inputs and sixteen digital inputs are acquired. The analog inputs are the voltages of phases R, S and T, currents of phases R, S and T, homopolar voltage and the homopolar current. The main specific parameters to be monitored are the root mean square value and phase shift of each analog input, status of each digital input or logical functions associated, active and reactive powers, monitored electrical line impedances. The waveforms of all analog input signals, the status of each digital input signal and the phase diagram of the currents and voltages for the R, S, T phases are also displayed. © 2015 IEEE. Source

Purcaru D.,University of Craiova | Purcaru A.,VIG IMPEX
Journal of Electrical and Electronics Engineering | Year: 2011

The recording of some high speed transient events specific to energetic systems imposes a high sampling rate for each common-mode or differential analog voltage and even a synchronized sampling of all analog inputs. This paper presents a method for synchronized sampling of 8 common-mode or differential analog inputs, with high and settable sampling rate; a PC104 bus compatible interface implements this method. The authors describe in detail the analog-to-digital module configuration and operation, data storage and reading technique and some software design considerations. There are programmable electronic modules for analog and digital signal acquisition which run in energetic systems and already use this method for synchronized sampling of analog inputs. For example, a disturbance monitoring device which computes the RMS value and phase shift of each harmonic of the analyzed signals. Source

Purcaru D.M.,University of Craiova | Purcaru I.,VIG IMPEX | Gordan I.M.,University of Oradea
2013 17th International Conference on System Theory, Control and Computing, ICSTCC 2013; Joint Conference of SINTES 2013, SACCS 2013, SIMSIS 2013 - Proceedings | Year: 2013

Many power quality problems are generated by various electrical events (faults, disturbances, etc.). This paper presents the PC-08/104 equipment for monitoring and analysis of transient electrical events in power systems. It is a programmable electronic module which runs according to the signals provided by the transducers that take over the process parameters. PC-08/104 performs the acquisition of analog and digital inputs, local data storage, monitoring and processing, data transfer to an IBM-PC compatible computer and communication with the process server in a distributed data acquisition system. The program which runs on an IBM-PC compatible computer contains three sections: Monitoring (configuring all settable parameters of the equipment), Analysis (visualization of the input signals waveforms and the computation of several characteristic values) and Manager (management of records and archives). PC-08/104 provides an excellent tool to analyse the performance of the power system before, during and after a network disturbance situation. Some experimental results obtained using this equipment in energetic system are also presented in the paper. © 2013 IEEE. Source

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