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Power quality distortions such as voltage unbalance and harmonics are usually present in power supply systems (PSS) simultaneously. These distortions have effect upon the most consumers' and PPS' equipments in the similar way and lead to the power losses rise, overheating and reduction of operation life of electrical equipments. Meanwhile electromagnetic compatibility (EMC) standards set limits of...
The development of a power quality (PQ) benchmarking model is presented. Practical results are discussed to motivate the need of adding value to recorded PQ data by means of benchmarking PQ performance. The importance, science and methodology of cleaning up recorded sag and swell data per site and per region is demonstrated. Benchmarking of voltage distortion, unbalance and magnitude regulation is...
Peculiarities of different kinds of load in relation to produced flicker effects are presented in the paper. The analysis bases on the measurements performed in low voltage installations of an industrial object using a conventional power quality instrument. Selected types of the load: laser-cutting machines, welding devices and electrical drives were chosen in order to observe the specific properties...
Little business integration of power quality management (PQM) is forthcoming amongst electrical utilities all over Southern Africa. Restricted access to proper information is the main reason. A integration of tools, procedures and people is required before an electrical utility can be operational in management of the quality of electrical energy. The South African NRS 048 document describes the minimum...
The method of integrated assessment of electric power loss caused by poor power quality in power supply systems based on the structural analysis of loss was suggested. It was demonstrated, that in power supply systems with low observability power loss, caused by power quality distortions, should be estimated considering the degree of completeness and validity of source information. The results of...
Dynamic voltage restorer (DVR) is a power electronic device used to compensate supply voltage disturbances e.g. voltage dips. The paper describes laboratory model of 3-ph dynamic voltage restorer with a multiloop controller which uses a gradient estimator of the capacitor current. The estimator allows for dynamical properties improvement without measuring actual signals. The DVR utilizes progressive...
The paper deals with a general form of a mathematical model of a three-phase electric circuit characteristics. A form of the model with using dimensionless variables is discussed. In general form of the linear AC circuit, the steady-state circuit characteristics are nonlinear functions of circuit elements and signals parameters. The linearized model of the asymmetrical circuit with linear loads is...
This paper describes a novel approach to monitor power quality in a large 33 kV distribution network with minimal power quality recorders. This is achieved by using an intelligent driven application which is pseudo-measurement based, to approximate the bus voltages and currents at various busses in the network. Bus impedance matrix is manipulated by rewriting the node-voltage equations for an n-bus...
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