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The electric power system, as an integrated system for transmission, distribution and consumption of electricity, is one of the most complex technical and economic systems today. Customers affect on the voltage quality of power network, but the network also has an impact on customers. All disturbances in the network can disrupt operation of the network and affect on operation of the customers, as well as reduce the level of efficiency and operation life or even seriously damage network. Number of customers is increasing every day, as well as proportion of customers who generate disturbances in the network and, at the same time, are sensitive to them. These circumstances impose the need for frequent monitoring of the network, so the analysis of power quality is not unjustified cost but extremely important and profitable investment. The quality of electricity, as part of the overall quality supply of electricity customers in deregulated conditions of liberal electricity market becomes significant regulatory parameter for network operators and a significant contracting parameter on the electricity market. Network operators are obliged to establish a system of individual measurements and a system of permanent monitoring of power quality parameters to determine the state and improve the parameters to the standardized level. Technical parameters are determined by the recommendations made at the international level and may, but do not need, be legally binding. Maintaining a certain level of voltage quality at some point of the network is the responsibility of electricity distributor. This task distributor executes by limiting of negative effects of producer/customer to the network. Therefore, each electricity producer/customer is obliged to reduce own negative feedback effects (injection of higher harmonics, taking of reactive power, emissions of flickers and loads unbalances) to a prescribed, prearranged, limited values. There are many norms that describe the quality of electricity, but in Europe the best known is EN50160 (issued by CENLEC). This paper presents the approach to measuring the voltage quality at the point of electricity delivery from distributed source into distribution network from the aspect of limiting the negative feedback of distributed source on the voltage quality.

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For Internal Auditors the ability to work smarter will increase in importance over the coming year. Sharing information and knowledge between internal audit teams will be crucial. The experts of the ECIIA offer you insights and their knowledge about Internal Audit Standards & Professional Practice Framework, Corporate Governance & Risk Management, Internal Audit Practices and the future of Internal Auditing. An excellent overview about recent developments and requirements for European Internal Auditors!

There are numerous practical problems for which we need to know the spatial distribution of artificialy created electromagnetic fields, generated by the human due to advances in technology and widespread use of electrical devices. Low frequency electromagnetic fields around power transmission and distribution networks are time-varying quasistatic electromagnetic fields that have a conservative (non swirling) component of low frequency electric field caused by charges and low frequency swirling component of the magnetic field caused by currents. Compactization of power facilities or devices, reducing the mass of the conductors, the calculation of swirling currents or induced electromotive forces in low frequency circuits, designing of structures for a human protection from electromagnetic fields as well as designing of the facility itself, are only some of the practical issues where the knowledge about time changing of spatial distribution of electromagnetic field is essential. This paper elaborates the results of three-dimensional calculation of stationary, sinus variable low frequency electromagnetic fields of the wind turbine, with complex configuration of elements, consisting of 7 wind aggregates, rated power 1.5MW, type LTW77-1.5, the manufacturer Leitwind, in the software package EFC-400. Analyzing of these calculation results is necessary to point at possible weak spots and give a proposal for measures for elimination of the electromagnetic influences or reducing them to acceptable level.