MODERN METHODS OF REACTIVE POWER COMPENSATION IN PETROCHEMICAL PRODUCTION

Electrical circuits of reactive power compensation on the basis of thyristor control circuits in the power supply system of oil refineries are considered. The main advantages, advantages over traditional reactive power compensation systems and directions of introduction into the power supply system of modern production are formulated.

PERFORMANCE ASSESS OF SELF-EXCITED IG DRIVEN BY WIND TURBINE WORKING WITH FC-TCR

This work presented a self-excited induction generator (SEIG) model controlled by an (FC-TCR) fixed capacitor-thyristor control reactor consisting of a large fixed capacitor in parallel with a thyristor controlled reactor in series with the constant inductance. Induction machines were used because they are capable of working at different speeds. The 3-phase IG was driven by the prime mover that represents the wind turbine. Also, constant voltage and frequency were obtained, regardless of the change in velocity, by using proportional integration (PI control) for each of them. This type of generator is used in isolated rural areas far from power transmission lines. The voltage and frequency are analyzed for each wind speed proposed in the model and calculating the required excitation amplitude and torque required to drive the induction generator. Therefore, it is now a key interest to develop an efficient, viable, economic, and controllable induction generator for harnessing energy from renewable sources. The strategy of control was implemented with MATLAB/Simulink.

Microcontroller based Automatic Power Factor Correction for Industrial Power use to Minimize Penalty

In this proposed system, two zero crossing detectors are used for detecting zero crossing of voltage and current. The project is meant to attenuate penalty for industrial units using automatic power factor correction unit. The microcontroller utilized during this project belongs to 8051 family. The interruption between the zero-voltage pulse and zero-current pulse is duly generated by suitable operational amplifier circuits in comparator mode is fed to 2 interrupt pins of a microcontroller. The program takes over to actuate appropriate number of relays from its output to bring shunt capacitors into load circuit to urge the facility factor till it reaches near unity. The capacitor bank and relays are interfaced to the microcontroller employing a relay driver. It displays delay between this and voltage on an LCD. Furthermore, the project is enhanced by using thyristor control switches rather than relay control to avoid contact pitting often encountered by switching of capacitors because of high in rush current.

Design of Three-Phase Induction Motor Starting Drive Based on Electromagnetic Torque Analysis

The process of starting a three-phase induction motor consumes a very largecurrent from the power grid, which can cause voltage drops and damage the coilinsulators due to the heat generated. However, this has been overcome by using severalstarting methods including star-delta starter, starter with autotransformer, soft starter,and drive frequency or better known as VFD or VSD. In conventional soft starters, asmall reduction in voltage results in a sizable drop in electromagnetic torque. This cancause a motor with a certain load to fail to start. In this research, a three-phase inductionmotor soft starter modeling will be carried out using the method of setting the sourcevoltage and frequency, designed to overcome the low electromagnetic torque generatedby conventional soft starters. The modeling of the soft starter with thyristor control isexpected to produce high and stable electromagnetic torque. So that the soft starter withthyristor control can be a solution for conventional soft starters.

Experimental determination of suboptimal parameters for energy-efficient control of an induction motor

The article presents the results of experimental studies of the automatic speed control system (ASCS) of an induction motor (IM). Preliminary experimental studies have shown that the stator current minimum (power factor) is a suboptimal criterion. Optimal in terms of control is the rated power factor. Tests of IM with a thyristor voltage converter (TVC), as a power source, were conducted on an installation created at the department. A mathematical model of ASCS IM corresponding to the experimental setup has been developed. To determine the main functional dependences of IM, such as stator voltage, stator current, power factor, torque on the shaft, a program for approximating experimental data by polynomials was developed. Using the developed mathematical model, the regulatory characteristic of IM that was optimal from an energy point of view was obtained. The necessary indicators of IM and TVC are determined (thyristor control angle, stator voltage, stator current) to change existing settings in order to save electric energy. The results of experimental studies are presented, the graph shows an optimized version of the form of the regulatory characteristic according to the criterion of minimum electric energy consumption.

Thyristor Voltage Regulator Experimental Research

The article is devoted to the thyristor voltage regulator (TVR) development. The TVR purpose is to control power flows and regulate voltage in 6-20 kV distribution electrical networks (DEN). The principle of TVR operation is based on the plus EMF (or minus EMF) introduction into power line when the shared use of longitudinal (change of magnitude) and transverse (change of phase) voltage regulation. The description of the TVR prototype is given. The TVR prototype consists of a 0.4 kV thyristor switches, power transformers (shunt and serial) and a 6 kV switchgear. The TVR has a two-level control system (CS). The TVR prototype experimental research was conducted in four stages: check of power equipment, first level CS research, second level CS research, prototype tests as a whole. The connection diagrams (thyristor switches unit, transformer and measuring equipment) and contact connections reliability were checked when the power part was tested. A qualitative characteristic of the input and output signals was obtained when testing the first level CS. It is found that the thyristor control pulses are formed according to the developed algorithm. The correctness of control system algorithms, executed and transmitted commands, passed and received data was confirmed as a result of the second level CS tests. The TVR research results indicate that the prototype provides the smoothness and specified accuracy of voltage regulation in all modes. The control range of the output voltage relative to the input was ±10%. The discreteness of regulation did not exceed 1.5%. The range of change in the shift angle of the output voltage relative to the input was ±5°. Research confirmed the TVR ES operability and its readiness for trial operation.

MATHEMATICAL POWER FLOW MODEL IN AN ELECTRICAL SYSTEM CONTAINING A SERIAL COMPENSATOR THRISTOR CONTROLLED REACTIVE COMPONENT

A unified mathematical model of the power flow in a system containing a reactive component compensator consisting of capacitor banks connected in series to a thyristor control reactor is presented. The application of the FACTS (Flexible Alternative Current Transmission System - Controlled flexible DC power transmission) technology is shown to reduce the gap between the controlled and unmanaged modes of operation of the electric power system (EPS), presenting dispatching personnel with additional degrees of freedom in the management of power flows and voltages in excess and deficit areas of the electric network. The main objectives of the FACTS technology application are studied: increasing the transmission line capacity to the thermal limit; optimizing power flows in a complex heterogeneous network; increasing the static and dynamic stability of the electric power system. To assess the action of the new generation of regulators of the power system, two alternative models of power flow in the electric power system are considered. In the first model, the concept of alternating series reactance is used as a state variable. In the second model, the characteristic of the advance angle is used, given in the form of a nonlinear dependence in the problem of calculating the power flow using the Newton-Raphson method. Conclusions are made on the presented models of power flow allowing to estimate possibilities of the serial capacitor with thyristor control TCSC (Thyristor Controlled Series Capacitor), as FACTS device, on improvement of modes of functioning of electric power system.

Dynamic and Stability Analysis of Wind-Diesel-Generator System With Intelligent Computation Algorithm

In this chapter, the dynamic performance of a wind-diesel-generator system has been studied against wind and load perturbations. The wind perturbation is modeled by simulating base, ramp, gust, and random wind. An optimized cascade tilt-integral-derivative (CC-TID) controller is provided to the test system for producing desired control signal to regulate the blade pitch angle of wind turbine. To confirm the efficacy of CC-TID controller, the output results are compared to that of PI- and PID-controller. The optimum gains of the proposed controllers are explored employing Levy-embedded grey wolf optimization, whale optimization algorithm, drone squadron optimization, and search group algorithm. To show the effectiveness, the output results are compared to the results of genetic algorithm and particle swarm optimization tuned controllers. A thyristor control series compensator (TCSC) is provided to WDG model for increasing the damping of system oscillations. Analysis of the presented results confirm the supremacy of CC-TID-TCSC controller over other controllers provided in this chapter.