The paper considers formers of orthogonal components of the first, second and fifth current harmonics. The formers are made on the basis of the Goertzel algorithm. The paper also contains investigations of frequency and dynamic properties of these formers.

The formulas for determination of economically reasonable values of distribution transformers load factors in 6-10 kV networks are received. It is shown that for rapid identification of "centers" of losses it is enough to carry out the calculation and analysis of modes of distribution networks based on their equivalents. Calculations of electric networks with optimal load factors of transformers allow us to determine reasonable levels of losses in distribution networks and can be used to develop corrective actions to reduce losses.

The paper proposes a real-time calculation algorithm of oil, winding and magnetic core temperature of power transformer on the basis of measured values of tank surface temperature and air temperature without measuring current. The algorithm is based on the calculation of the equivalent load factor of the transformer. Imitation simulation has confirmed efficiency of the algorithm. After tests on functioning transformers the algorithm can be used in thermal protection devices and diagnostic devices for power oil transformers.

A synthesis of adaptive PID controller has been executed for flux linkage and speed channels of a vector control system for an induction short-circuited motor. While using an imitation simulation method results of a synthesized system analysis show that the adaptive PID controller has some advantages under conditions of parametric disturbances affecting the object.

The paper describes main principles of the methodology for control of efficient energy use in power engineering and economy sectors as a whole. Targets for control of energy use at different levels have been considered in the paper. A special attention has been paid to technical, organizational and legal aspects of energy efficiency improvement. The paper contains an analysis of the history of the given issue, the present level of its development and near-term prospects under conditions of the Republic of Belarus.

The paper investigates determination of energy portion from renewable energy sources in relation to total generated electric power for electricity supply of consumers.

The paper presents method for joint identification of an active stator and rotor resistance of an induction motor on the basis of fuzzy logic controller. The problem is solved for the induction motor model presented in d–q coordinates and rotating with synchronous speed. The conditions required for the possibility of identification test have been determined in the paper. The paper has analyzed an effect of mutual inductance deviation, stator and rotor inductance deviations from their true values on the identification accuracy. The proposed method is applicable under conditions of steady state drive and runs in two phases. The simulation results indicate a high speed and accuracy of parameter identification.

The paper considers a potential, energy and economic efficiency of joint activities of enterprises of the Ministry of Energy sector and enterprises of the material sector of the economic complex of the Republic of Belarus on the basis of the methodology for intensive energy saving. Such calculated values as annual savings of natural gas in Belarus – up to 1 million tons of fuel equivalent, release investment for the Ministry of Energy – up to 1 billion USD, range for changes in electricity generation during a day - up to 1 GW with a specific consumption of fuel equivalent – 160 g/(kWh) have been determined while taking thermal technology of asphalt concrete mixture production and regulation of electricity generation as an example. Fuel saving system and investment return create preconditions for realization of the project by private investors.

The paper proposes rapid methods for transfer function coefficient determination of superheater sections under various loads while using a universal nomogram based on initial data of one load. The rapid methods make it possible to obtain analytical nonlinear dependences pertaining to changes of superheater transfer function parameters through the channel of regulatory impact, that provides parameter optimization of the dynamic knob injection adjustment throughout the whole range of power block load changes.

The paper considers main technological methods for biogas purification from impurities that permit to increase energy value of the product and decrease its corrosion activity.  While evaluating economic efficiency due to introduction of the corresponding purification technology, in addition, it is necessary to take into account an ecological factor.

The paper describes hydraulic tests of discharge capacity and pools conjunction in respect of dam spillway of Jambor weir at the Polotsk hydroelectric station. The process of ice passage through the spillway dam has been studied in the paper. The paper contains recommendations on safety depth downstream.