# Selecting of Mathematical Models for Determination of Energy Production Facilities “Standards” on the Basis of a Multi-Criteria Approach

The necessity of improvement of approaches monitoring energy resources consumption efficiency, which are applicable today in Ukraine and are based on a system of rationing of specific expenses of fuel and energy, is analyzed. For this purpose the possibility of application of the operational management of fuel and energy resources consumption efficiency, which represent set of so-called systems of planning and control of energy consumption was shown.

# Selection of Stabilitrons and Modes of the Power Supplies of Reference High-Voltage Installations of the Direct Current

The problem of stabilitrons selecting for use in reference high-voltage installations of a direct current, calculation of a high voltage pulsations are observed at various modes of operation of such installations and definitions of methods of their amplitude decreasing. Problems of support of the stable power supplies of reference installation depending on characteristics of an alternating voltage source selection and the circuit design of this voltage transformation are analyzed.

# Calculating of the Heat Physic Characteristics of the Exhaust System of the Diesel Combined Internal Combustion Engine

The purpose of research is to determine the coefficients of dynamic and kinematics viscosity, thermal conductivity of the exhaust gas of diesel CICE for typical states of exhaust systems. The research application methods are based on theories of gas mixtures using the Sutherland reduction formulas, combustion of liquid hydrocarbon fuels at the rate of stoichiometric proportions.

# Calculation of Basic Characteristics of the Humidity Sensor Transformer Oil

This article outlines the method of calculating the sensor coefficients based on the sensory element of the insulating paper and highlighting features of this calculation. The sensitive element of the sensor belongs to conductometric type of the transducer “moisture–resistance”. The sensor is designed for use in the automated control moisture in transformer oil power transformers and reactors.

# Errors Analysis of Measuring Instruments of Three-phase Voltage Asymmetry

This article is devoted to the increase of exactness of measuring three-phase indexes of quality of electric power in the systems of three-phase power supply. We analyze transformation equations of three-phase voltage of six-pole is in-process executed with three by an entrance and by three output clamps. We show that four complex coefficients fully characterizing this six-pole can be entered.

# Assessing the Possibility of Using Insulating Paper as the Transformer Oil Humidity Sensor Element

This paper determines possibilities of using insulating paper as a humidity sensor element for monitoring the humidity level of transformer oil in power transformers. We propose to construct the sensor unit of the humidity sensor as a cylindrical capacitor structure, in which the dielectric is the electrically insulating paper soaked in transformer oil. Moreover, we conduct the investigation of relation between conductivity of insulating paper, transformer oil and moisture; temperature and electric field occurring at measuring their resistance at a constant voltage.

# Multifunction Transformer-Valve Converter for the Complex Power Quality Improvement of Three-Phase Systems with Variable and Nonlinear Load

This paper analyzes the design features and functional capabilities of the automatic filter-balancing device (AFBD) developed to ensure electromagnetic compatibility of the important electric energy consumers with the power supply, optimization of low-voltage distributive networks behavior, voltage and energy loss saving, complex power quality improvement.

# Using Cold from Snow, Ice and Ground for Cooling Small Data Centers in Ukraine

In this paper, we consider using renewable sources of cold (snow, ice and ground) for cooling server premises. We determine the required volumes of snow and ice for an average capacity of 10 kW during 7 months in southern regions of Ukraine and 4 months in the northern regions of Ukraine. The volume of snow and ice accumulators intended for 7 months of operation taking into account accumulation efficiency coefficient is about 2000 and 1000 tones. The ice and snow accumulators require the area from 50 to 300 square meters.

# Method of Setting H∞-Pidregulators for Objects with Delay

Given the widespread use of PID controller and the presence of uncertainties for thermal facilities, the synthesis method should be developed. It can be instrumental in obtaining sufficient robustness and providing practically important quality indicators of the closed loop system within the set limits of uncertainty besides unconditional stabilization facility with delay. Using the optimality criterion as H∞ norm closed system, we obtain PID controller settings for objects with delay.

# Increasing the Efficiency of Frequency Load Shedding of Power System

The paper considers the frequency load shedding of an electric power system. The objective of this paper is to enhance the structure and algorithms of frequency load shedding-1 (AUFLS-1) using cutting-edge technologies, namely Wide Area Measurement System. We model the operation of the system of complex power supply when various emergencies in the Power Factory software occur. We aim at revealing the fact of the voltage corner reaction on the emergency occurrence and elaborating the algorithm of detecting the emergency by speed of voltage corner change.