A. Sudrià

Development and implementation of a condition monitoring system in a substation

Maintenance is a key activity for utilities in order to assure the proper operation of their networks. And it implies a huge amount of human and economic resources. Saving maintenance costs means that it is needed to invest in innovation. In order to improve the effectiveness of the maintenance in the electrical utilities, a transformation from preventive maintenance based on time (TBM) to preventive maintenance based on condition (CBM) is taking place. The core element of the CBM strategy is the implementation of a condition monitoring system. This work treat about the development and implementation of a condition monitoring system in a pilot plant of an electric utility consisting in a 66/25 kV, 30 MVA power transformer and 66 kV and 25 kV circuit breakers. The system was implemented by using the monitoring functions of commercial protection relays equipped with IEC61850 communication capabilities. In this work, first a description of the monitoring system is presented, followed by the description of the pilot plant where the system has been installed and finally, the conclusions and further works are presented.

Sensorless control of PM synchronous motors and brushless DC motors - an overview and evaluation

This paper provides a review of the literature addressing sensorless operation methods of PM brushless machines. The methods explained are state-of-the-art of open and closed loop control strategies. The closed loop review includes those methods based on voltage and current measurements, those methods based on back emf measurements, and those methods based on novel techniques not included in the previous categories. The paper concludes with a comparison table including all main features for all control strategies

Assess the impact of photovoltaic generation systems on low-voltage network: software analysis tool development

The integration of photovoltaic generation systems into power networks can cause both benefits and drawbacks. However, utilities have to control and operate their systems properly, in order to assure the availability and quality power supply to the users. Therefore, utilities should consider technical constraints and existing regulation in order to assess the impact of photovoltaic systems and limit their integration. On the other hand, regulation includes few operation constraints and they are not implemented in current software analysis tools. In the present paper a tool for assessing the impact of PV integration on low-voltage networks is described. The voltage fluctuation, the inversion of the power flow and the increase of short-circuit capacity are the problems considered in the proposed tool. Further work will focus on harmonics distortion.

All-digital resolver-to-digital conversion

In this paper, an all-digital resolver-to-digital converter is presented. Using oversampling and frequency shifts techniques, along with a synchronous rotating reference frame based PLL, an accurate and fast tracking resolver-to-digital converter is presented. With the use of all these combined techniques, and using a standard DSP with a 10 bits ADC, resolutions of up to 12 bits are feasible. This paper presents the main techniques, simulation and experimental results

A laboratory test bed for PM brushless motor control

There has been tremendous growth in the use of modern digital signal processors (DSP) in control and other applications in the past few years. While courses offered in the electrical and computer engineering disciplines cover such topics as mobile and digital communications, image and sound encoding and decoding, few courses focus on the use of DSP in real-time control of electrical machinery. On the other hand, there is a growing need in industry for engineers who can perform control design and system integration for various applications in motor control. This paper describes a laboratory test bed for PM motor control for a new course on control of electrical machinery offered at School of Industrial Engineering of Barcelona ETSEIB, Polytechnic University of Catalonia, Barcelona, Spain. An outline of the course structure, laboratory setup, and the design aspects for implementing modern real-time motor control applications are presented

Static switches for their use on capacitors batteries connection

Nowadays, most of the reactive power compensation applications work with electromechanical switches, but there are some applications that require fast response in compensation, like, for example, soldering industry. There are other applications that need a connection without disturbance generation. The connection of capacitors batteries can affect, for example, near electronic equipment. These problems can be solved using a static switch instead of an electromechanical switch. This paper presents a study about different topologies of static switches for their application on controlling capacitors batteries connection. To begin with, the paper shows a brief description of mains characteristics of static switch. Then, five different structures are presented. These structures are based on different combinations of thyristors and diodes: 4T (four thyristors), 6T (six thyristors), 6TS (six thyristors with single-phase capacitors), 3T-3D (three thyristors and three diodes), 2T-2D (two thyristors and two diodes). The behaviour of each structure has been simulated on its opening and closing states and are discussed the advantages and disadvantages of using each of it. Finally, is reported which structure has been chosen and are attached some real experiments made with a prototype.

Frontier Methodology to fix Quality Goals in Electrical Energy Distribution Companies

It is necessary to have tools that allow the regulator, or the distributor, to fix the quality goals according to the electrical system of the area, taking care about the special characteristics that every distribution company has in front of the others. This article presents a methodology which allows having a simple tool for making this comparison and for fixing the quality goals in a possible time horizon

High Power UPS Selection Methodology and Installation Guideline for High Reliability Power Supply

This paper presents the most common UPS technologies for high power available on the market and compares their functional parameters. Also it presents the most important UPS parameters that must be considered to design the high reliability facility. Different configurations and the influence of the parameters on the UPS operation are discussed. All steps of this selection process were put into practice in order to select UPS systems for installations of RETEVSION, one of the most important telecommunication companies in Spain. The operation behavior of the installed UPS was confirmed by on site measurements.