ASSESSMENT OF COST-EFFECTIVENESS OF IMPROVING ENERGY PERFORMANCE IN NETWORKS WITH SEMICONDUCTOR CONVERTERS
Various methods of improving the quality of electricity networks with semiconductor converters are discussed. Among them, the use of network reactors, transition to multi-pulse schemes, the use of filter-compensating devices with a step and indirect regulation. The allocation of modern means of improving the quality of electricity allocates frequency converters with an active rectifier and semiconductor sources of reactive power on a fully controlled power switches. Technical and economic aspects of the use of filter-compensating devices are discussed for two cases: the power of the power lines and the system of autonomous power supply. The results of instrumental research at one of the oil-extracting enterprises with extensive use of centrifugal pumps with variable frequency drive are presented in the form of voltage and current waveforms at the input of 6 kV- distribution device, their spectral composition. The graphs show that the shape of the voltages and currents is strongly distorted. During the execution of the technical-economic calculations of various options main indicators of economic components, such as capital and ongoing operating costs, are discussed. In addition to the differences between the systems in terms of quality of electricity, the amount of impairment loss of its quality is added to the described expenses. If it is unable to calculate the losses, the cost of purchasing power quality controls is calculated. When powered from a stand-alone power supply system one option is widely used in practice, when diesel generators are used as an autonomous source of energy. In this case, presented costs, unlike the previous one, consist of annual costs for the production of electric energy by diesel generators. Methods of calculating the costs of technical implementation of means improving the quality of electricity in the power network implemented in the power systems of the power lines and systems with autonomous power supply are discussed. An example of the calculation, which implements the method of determining the effective use of power quality controls, is given.