This paper proposes two methodologies that are extended from the existing Cascaded Multilevel Inverter Employing Three-Phase Transformers and Single DC Input topology . The proposed circuit configuration can reduce the number of switches required to convert the input DC power into AC power when compared with traditional method. However Simulation results reveals that the THD variation of the pr...

in this paper, power system restoration in the presence of svc and tcsc in partial outage conditions is considered and a new method for maximum load restoration using different control variables is presented. control variables are tap of transformers, generation rescheduling and operating points of facts devices. objective function is restored load (to be maximized) and constraints are voltage ...

− The paper describes the systems, the standards and the procedures developed at IEN for the precise measurement of ac voltages in the millivolt ranges. Two different methods based on resistive dividers and wideband transformers have been developed and are applied for the measurements of respectively the ac-dc transfer difference and the ac voltages down to 1 mV.

Introduction The increased use of ac and dc motor drives in industrial plants has elevated the power quality application considerations associated with power distribution systems. These considerations have sparked great controversy about the use of drives in industrial applications and have raised questions about their effects on an electrical system. Valuable guide standards, such as IEEE 519-...

Service reliability in electrical power networks is of crucial importance and depends on the quality and availability of electrical equipment. Operation resources like power transformers have to be considered, representing the intersections of energy networks. Regarding the age of power transformers e.g. used in the German grid surveillance is gaining importance. An approach for evaluating the ...

Dry-type transformer becomes the preferable choice in many applications due to its construction specific advantages over oil-cooled transformers. However, the inherent low thermal conductivity of dry-type transformers gives the rise to high operating temperatures. The temperature rise of a transformer is an important factor deciding its safe operation and the useful life span. With the increase...

This paper deals with a medium-voltage distribution network. The feeders in the open-loop arrangement are changed to the closed-loop arrangement with the aim to improve reliability of the power supply. The paper focuses on the analysis of transient and steady-state operation in the closed-loop that is established by connecting feeders supplied from two different transformers located in the same...

This paper describes interconnection between technical and economical making decision. The reason of this dealing could be different: poor technical condition, change of substation (electrical network) regime, power transformer owner budget deficit and increasing of tariff on electricity. Establishing of recommended practice as well as to give general advice and guidance in economical sector, t...

Power transformers are designed to transmit and distribute electrical power. Depending on the size of a transformer, replacement costs can range from a few hundred dollars to millions of dollars. Performing offline and invasive tests also add to the replacement cost. Hence, there is an increasing need to move from traditional schedule-based maintenance programs to condition-based maintenance. A...

The paper presents a short overview of the state of the art for grid tied PV inverters at low and medium power level (1..100 kW), mainly intended for rooftop applications. The inverters are categorized according to the configuration of the PV system, the configuration of the conversion stages within the inverter and whether they use transformers or not [1], [3]. After the introduction of the st...