Automatic Power Control System Research Articles

Optimization of power feedback control system for HCN interferometer on EAST Tokamak

The Hydrogen Cyanide (HCN) interferometer stands as an indispensable diagnostic tool, designated to measure the line-integrated electron density on the Experimental Advanced Superconducting Tokamak (EAST), thereby offering essential density feedback signals for EAST operation. The HCN laser used in the interferometer is a continuous glow discharge gas laser. However, owing to variations in external ambient temperature, the HCN laser exhibits output power instability. The current power automatic feedback control system for the HCN laser interferometer exhibits low actuator adjustment precision, thereby limiting its ability to achieve maximum output power. Moreover, the system may cause a temporary power drop to zero during adjustment, while EAST operation requires the HCN laser interferometer to maintain high power continuously. In order to solve the issues, this paper developed an innovative actuator that ingeniously amalgamates the virtues of piezoelectric ceramic and stepper motor. This novel actuator, demonstrating a broad adjustment range and high precision, is intended to replace the present one in the HCN interferometer power control system. While the stepper motor executes coarse adjustment, the piezoelectric ceramic enables precise adjustment, thus enhancing the adjustment accuracy of the automatic power control system to a sub-micrometer level and an adjustment range greater than 5 mm. Accurate determination of the regulator's adjustment direction can significantly improve the efficiency of adjustment. The slope of the laser output power peak decreases as it approaches the maximum value, and increases as it moves away from the maximum value. Therefore, this system replaces the original threshold algorithm with a slope algorithm. By correctly judging the adjustment direction, the efficiency of adjustment is improved. Furthermore, this algorithm can keep the output power stable on a power peak. There will be no instances of zero power output during the adjustment, allowing the power to remain stable above the set threshold for a long time. Currently, this system has been successfully applied to the HCN interferometer, and testing has found that the system can maintain stability for at least 16 hours. Furthermore, even when the laser output power was intentionally reduced to below the set threshold, the system was able to respond quickly and adjust the output, rapidly restoring it to above the predefined threshold. Multiple tests have shown the strong robustness of the system, indicating it meets the stringent demands of the EAST's complex environment.

Enhancing of the power system resilience through the application of micro power systems (microgrid) with renewable distributed generation

The power sector plays a critical role in the functioning of the economy and the security of a country, being closely interconnected with other vital infrastructures, such as gas supply, water supply, transportation, and telecommunications. Ensuring a stable power supply is crucial for the uninterrupted operation of these systems. One way to enhance the resilience of the power system is by integrating local networks with distributed renewable generation into the overall energy infrastructure. The flexibility, stability, controllability, and self-healing capabilities of microgrids make them an effective solution for improving the resilience of the power system. The power grid is susceptible to disturbances and disruptions that can cause large-scale power outages for consumers. Statistical data indicates that approximately 90% of outages occur due to issues in the distribution system, thus research focuses on local microgrids with distributed renewable generation. This study analyzed the role of microgrids with renewable generation in enhancing the resilience of power systems. Additionally, functions of microgrids that contribute to enhancing power system resilience, such as service restoration, network formation strategies, control and stability, as well as preventive measures, were summarized. It was found that local microgrids have significant potential to enhance power system resilience through the implementation of various strategies, from emergency response planning to providing reliable energy supply for quick responses to military, environmental, and human-induced crises. The concept of local distributed energy generation, storage, and control can reduce reliance on long-distance power transmission lines, reduce network vulnerabilities, and simultaneously improve its resilience and reduce recovery time. It has been determined that the most necessary and promising approaches to enhance the resilience of the power system include developing appropriate regulatory frameworks, implementing automatic frequency and power control systems, ensuring resource adequacy (including the reservation of technical components), promoting distributed generation, integrating energy storage systems into the energy grid, and strengthening cyber security. Keywords: resilience, local power systems, MicroGrid, distributed generation, renewable energy sources.

Double-Circuit Adaptive System of Fuzzy Phase-Autonomous and Energy-Efficient Control of Arc Furnace Electric Modes

The article provides an overview of the existing structures of fuzzy model systems for arc length control and optimal control of arc steel-melting furnaces (ASFs) electrical mode. The analysis of known adaptive optimal control strategies of alternating current steel-melting arc furnaces modes according to complex criteria of energy efficiency, energy saving and reliability was performed. Expedient system engineering solutions are proposed for the comprehensive improvement of energy efficiency and electromagnetic compatibility of arc furnaces and the power grid, which are implemented by improving automatic power and arc length control systems. Control principles, indicators of arc length control dynamics, energy efficiency and electromagnetic compatibility of various systems are analyzed. The expediency of using fuzzy control models for comprehensive improvement of dynamics, energy efficiency and electromagnetic compatibility indicators is substantiated. The expediency of implementing simultaneous phase-independent control of arc lengths and fast-acting arc currents control is substantiated. A variant of the double-circuit structure of fuzzy arc lengths control system and implementation of the multi-criteria optimal control strategy of electrical modes (EM) is proposed. The design of fuzzy inference systems for the synthesis of the electrode movement control signal was carried out in order to improve the dynamic accuracy of the ASF electrical mode coordinates stabilization. A computer Simulink model of the developed double-circuit system was created, and studies of the dynamics and energy efficiency indicators when handling deterministic and random perturbations were performed. The obtained results of model studies showed an improvement of the control dynamics quality indicators under the influence of deterministic and random perturbations and an increase in the energy efficiency of ASF EM at various technological stages of melting. The expediency of the practical use of the proposed solutions for operating arc furnaces is substantiated.

Adaptive Control of Energy Storage Systems for Real-Time Power Mediation Based on Energy on Demand System

The concept of i-Energy as a new smart demand-side energy management system is proposed, which can realize the versatile and efficient control of e-power flows between distributed generators, numerous appliances, and energy storage systems in the home domain, factories, offices, and local communities. The Energy on Demand (EoD) system is proposed, which is the automatic power control and management system that supplies power to home appliances based on the power demand requests issued from the home appliances. The EoD system can guarantee the reduction in total power consumption by implementing a ceiling control while keeping the quality of life (QoL) of the home user considering the limitation of power supply. This paper proposes an adaptive battery storage management and control method based on the EoD system, which we call the “storage-supported EoD system”. In particular, the storage-supported EoD system can handle multiple power generators, including storage batteries. The overall goals of this paper are not limited to the extension of multiple power supplies only; rather, it provides additional contributions, which are (i) extend the existing power consumption control of home appliances and peak demand shift control (i.e., EoD system) by adding a second power source, i.e., a storage battery system; (ii) propose adaptive storage system design and management for the EoD system; (iii) realize minimum storage capacity for large peak power consumption; and (iv) minimize the home user’s discomfort level due to the limited power supply of one power source. The simulation results have shown the effectiveness of the proposed algorithm with a couple of experiments using real-life data in the smart apartment room. Additionally, simulation results are presented to compare and evaluate the proposed system performance with the EoD system.

Optimization of automatic power control of pulsed reactor IBR-2M in the presence of instability

The paper presents the main results of computational and experimental optimization of the automatic power control system (AС) of the IBR-2M pulsed reactor in the presence of a high level of oscillatory instability. Optimization of the parameters of the AС made it possible to significantly reduce the influence of random and deterministic oscillations of reactivity on the noise of the pulse energy, as well as to sharply reduce the manifestation of the oscillatory instability of the reactor. As a result, the safety and reliability of operation of the reactor has increased substantially.

Information supply of the power control system of the synchronous generator of the autonomous wind unit

This paper deals with information supply of automatic maximum power control system of synchronous hybrid excited genera-tor for the autonomous wind unit. The power supply system based on an autonomous wind turbine consists of an electric generator, a battery charging controller, a battery pack and an inverter, which provides the required frequency and valueof the consumer's supply voltage.Three phase permanent magnet synchronous generator that have high technical and economic indicators are most widely used as electric generator of autonomous wind turbines.The main disadvantage of these generators is the lack of effective methods of magnetic flux control, limiting the optimization of the energy balance of the wind turbine.The paper discusses the application of synchronous generator with hybrid excitation system that consists of permanent magnets and additional field excitation winding lo-cated on the stator. Mathematical model of a hybrid excited synchronous generator is presented. Also,an output maximum power control system in a case of wind speed change by varying field excitation current is developed. Control system is developed based on concept of reverse task of dynamics in combination with minimization of local functionals of instantaneous values of energies.In the basics of the control method is put an idea of the reversibility of the Lyapunov direct method for the stability analysis.Obtained con-trol law provides thesystem stability inwhole, which allows solving control tasks of interrelated objects via mathematical models of local loops. Control law also provides low sensitiveness to parametric disturbances and gives dynamic decomposition of interrelated non linear system that ensures its practical implementation. The study of the proposed power control system based on parameters of hybrid excited synchronous generatorexperimental sample has been carried out. The graphs of transient process of armature power, voltage and current in a case of wind speed change from 3 to 8 m/s were obtained, as well as in a case of active resistance load change. The results of study showed high efficiency of power control of a wind turbine with hybrid excited synchronous generator.

Implementation of an Automatic Frequency and Power Control System at Pregol’skaya TPP

Implementation of an Automatic Frequency and Power Control System at Pregol’skaya TPP

The research on the dynamics of the three-impulse system of automatic control of water supply to the steam generator when the load changes

The paper analyses an operation of the typical three-impulse automatic control system (ACS) of the steam generator water supply. A mathematical model has been developed to test its operability for load shedding, allowing you to set maximum deviations of the water level without full-scale tests, without adjusting the operation settings technological protections by the level of water in the drum. Reasons identified static regulation errors when working out internal and external disturbances in the flow rate of superheated steam in a typical ACS. The relevance of modernization of a typical ACS power supply to the steam generator water. Altogether, under all influences, a significant improvement in the quality of regulation was obtained compared to a typical three-impulse automatic power control system. The relevance of modernization of a typical system of automatic control of water supply of a steam generator to eliminate static regulation errors in a wide range of changes loads.

Synthesis of Boiler Controllers of the Automatic Power Control System of Power Units

The article concerns the problem of structure-and-parametric optimization of a cascade automatic control system (CACS) by an example of a boiler power controller and a fuel controller. This CACS, which is a part of automatic control systems for power units, consists of two loops, viz. of an inner loop (which purpose is stabilization of the system) and an outer loop (designed for the adjustment) and, also, of two controller, viz. an outer controller (which is a basic one) provided for stabilization of the output value of the object (in our case, of the actual power unit capacity) and of an inner controller (which is an auxiliary one) provided to regulate fuel consumption. The internal controller builds up the control action with the aid of the boiler load controller of the power unit. As compared to single-loop automatic control systems, the cascade system provides better quality of transient control due to the higher performance of the internal loop of the system. This advantage is especially noticeable when compensating for disturbances that come through the channel of regulating impact. The article presents two methods of setting, viz. the fuel controller and the boiler power controller. The application of these methods can improve the quality of power control and reduce fuel consumption in transient modes in comparison with the setting of these controllers of a typical power unit automatic power control system. The results of computer simulation of transient processes in CACS for input step surge and internal perturbation confirm the advantages of the methods are presented in this article.

Features of Automatic Control of Technological Parameters of Water Level in the Drum Steam Boilers

The three-pulse system of automatic control of the water level in the boiler drum received maximum distribution in the energy sector, as well as its modifications, which have the following disadvantages : the presence of static control errors at the end of the transition process in the development of internal disturbances and disturbances of superheated steam flow; large level deviations with sharp and significant changes in the load, which often leads to unloading or shutdown of the boiler or power unit. To eliminate these drawbacks, invariant systems for automatic regulation of the power supply of the drum boiler were previously developed. In work the system of automatic control of technological parameters of water level in a drum of steam boilers is considered. The description of control systems and a detailed description of the electrical power systems of the control system are given. Various methods of tuning the PI controller of a typical three-pulse automatic power control system are considered. The application of the method of structural-parametric optimization and the theory of invariance makes it possible by changing the structure of the system and optimizing the dynamic adjustment of the automatic power control system to significantly improve the quality of maintaining the water level in the boiler drum. Invariant automatic control systems eliminate static control errors under all influences and can significantly improve the quality of maintaining the level under variable conditions. The methods are proposed to significantly improve the quality of water level control in the boiler drum, eliminating the shortcomings of the typical automatic control system. The results of the work can be used in the design of power control systems of steam drum boilers. The results obtained can be used in the development of adaptive control systems for other thermal power facilities.

Parametric Optimization for Automatic Control System of Power Units of 300 MW for the Mode of Variable Pressure of Turbine Inlet Steam

The article deals with the problem of parametric optimization of automatic control systems for power units of 300 MW of Lukoml’skaya GRES in the mode of variable pressure of turbine inlet superheated steam. The modernization of automatic power control systems of all power units of Lukoml’skaya GRES was carried out in the nineties of XX century for the last time. At the moment, these systems no longer meet all the requirements of the new standard, which regulates the participation rates of thermal power units in the normalized primary frequency control and in automatic secondary control of frequency and active power flows. According to this standard, the time to achieve the half value of the required power change should be 10 seconds within the normal and emergency reserves; the time to achieve the full value of the required power change should be 30 seconds within the normal reserve and 2 minutes within the emergency one. The construction of the Belarusian NPP is also being completed; its first unit will be put into operation in 2019, and the second one–in 2020. After the launch of the NPP, the Lukoml’skaya GRES power units will be necessitated to operate in a wide range of load changes. It is for these reasons that it is necessary to improve the efficiency of power units in particular and of the entire power plant in general. This can be achieved with the help of the outlined method of parametric optimization of a typical system of automatic control of power units, which allows improving the quality of control of turbine inlet steam power and pressure. The results of computer simulation of transient processes in the system illustrate the technique described in this article and confirm its correctness and undoubted advantages over other methods of optimization of typical systems of automatic control of power units.

Power coefficient of reactivity: definition, interconnection with other coefficients of reactivity, evaluation of results of transients in power nuclear reactors

It is assumed by the authors of the present paper that with growing contribution of nuclear power in the production of electricity, nuclear power plants will be used to a higher degree in a manoeuvrable mode of operation rather than in the base-load mode. In other words, change of power from the nominal level to that of coverage of auxiliary loads will be becoming quite common and not so rare event as scheduled reactor shutdowns for fuel reloading or preventive works. There exist well-known problems in the use of nuclear reactors in the manoeuvrable operation mode, which include the task shared by all types of nuclear reactors. It is advisable to have a unified indicator weakly power-dependent and fairly easy to measure, which would make it possible to formulate the judgement about the nature of the transient processes within the entire power range and to assess the reactivity required for changing the power level by the preset value. Power reactivity coefficient (PRC) can be used as such indicator. Analysis was made of existing definitions and understanding of PRC in relevant references. It turned out that there is no generally accepted definition of the PRC. Based on the performed study, the following definition was suggested: the PRC is the ratio of the low reactivity introduced into the reactor to the power increment at the end of the transient process. It is assumed here that variation of reactivity is dependent on the energy released in nuclear fission but is not related to the changes of reactivity induced by feedback signals in the automatic reactor power control system. Analysis of the relationship between the PRC and temperature coefficients and technological parameters associated with the steady-state control program was performed taking the above suggested definition into account. PRC calculations were performed using the simplest model of VVER-1000 type power reactor. It was found that PRC is weakly power-dependent. The purpose of the present study is to investigate dependence of PRC on the temperature reactivity effects and on the technological parameters associated with the steady-state control program of the power unit, using the example of VVER-1000. Effects of PRC on the static and dynamic power reactor operation modes are analyzed.

Mm‐wave power control

mm‐wave power control

Comparative Analysis of the Dynamic Properties of Variants of Automatic Frequency and Power Control Systems for Steam Power Plants Equipped with Once-Through Boilers

Considerably complicated power-system problems that have to be solved by the Russian power-generating units and, consequently, the need to ensure the fully automated operation of the power-generating units under working loads necessitated improving the structure of the automatic frequency and power control systems (AFPCSs). Not all solutions adopted in the 1980s, in particular, the use of the classical variants of the automatic power control systems (APCS-1 and APCS-2), ensure the required quality of suppressing power-system disturbances. In this work, the authors performed comparative analysis of six AFPCS variants that correspond to both the classical APCS-1 and APCS-2 and their combinations. The research was carried out using a mathematical model under disturbances of characteristic types, viz., those caused by network frequencies, unit power settings, and boiler loads. The model was developed by approximating experimental step response curves of the 300-MW power-generating unit 3 equipped with a once-through boiler at Kashirskaya State District Power Station. The quality of control was analyzed by comparing the amplitude-frequency characteristics and the curves of the transient processes of the compared AFPCS variants and the integral quadratic criterion values and the maximum deviations of the controlled variables and control actions in the course of the above processes. The combined AFPCS and advanced APCS-2 proved to be the most preferable. The combined AFPCS variants offer advantages in terms of maintaining the steam pressure, while the advanced APCS-2 has an advantage as a means for controlling the unit power with the gain in the first case being somewhat greater than that in the second case. Both variants have been successfully used for a long time at numerous power-generating units of the country.

Electrical engineering unit for the reactive power control of the load bus at the voltage instability

For the purpose of reactive power control error reduction and decrease of the voltage sags in the electric power system caused by the asynchronous motors started the mathematical model of the load bus was developed. The model was built up of the sub-models of the following elements: a transformer, a transmission line, a synchronous and an asynchronous loads and a capacitor bank load, and represents the automatic reactive power control system taking into account electromagnetic processes of the asynchronous motors started and reactive power changing of the electric power system elements caused by the voltage fluctuation. The active power/time and reactive power/time characteristics based on the recommended procedure of the equivalent electric circuit parameters calculation were obtained. The derived automatic reactive power control system was shown to eliminate the voltage sags in the electric power system caused by the asynchronous motors started.

Nonlinear properties of voltage and current transfer ratios for electric arc furnaces

A method of arc voltage gradient calculation for an electric arc furnace (EAF) is presented. The arc voltage gradient is the basic characteristic in study and simulation of an automatic power control system of an EAF. This characteristic is a strongly nonlinear multifactorial function that depends on electrical parameters of a power supply system, thermal conditions, and processes of arc heat exchange in an EAF melting bath. The method of arc voltage gradient calculation considers the relation between the electric and thermal conditions of an EAF in order to describe feasible nonlinear properties and to improve expressions for voltage and current transfer ratios as nonlinear multifactorial functions in particular. An EAF is regarded as a subject of control. Multifactorial properties are defined by the parameters of an equivalent electrical circuit of a furnace and by variable conditions of arc heat exchange in a melting chamber during steel melting. The method is effective for overcoming the uncertainty of the arc length in simulation of an EAR power controller. The unstable behavior of the furnace at a high impedance was explained using the obtained functions of the arc current and the arc voltage for various electrodes and the arc length. The minimum allowed arc current was found. The automatic power controller becomes unstable and the arc is extinguished under this value.

Техніко-економічні аспекти використання споживачів-регуляторів у системах автоматичного регулювання частотою і потужністю

Техніко-економічні аспекти використання споживачів-регуляторів у системах автоматичного регулювання частотою і потужністю

Control and Monitoring of Power Facilities as Per LFC Standard

The article brings closer the principle of operation of the new power distribution system, LFC, being the successor of the ARCM SOWE system. The majority of the study is concentrated on the architecture of the local LFC system node authored by IASE sp. z o.o. there have been brought closer, here, the problems of automatic unit control in accordance with the plans and commands from the central LFC controller, of the system operation monitoring via the integrated SMPP module as well as the problems connected with the new technologies employed by LFC (the protocol ICCP-TASE.2 and the standard IEC60870-6, among other things). There have been also described the most important components, SRM LFC, responsible, among others, for the exchange of data with the unit automation, archiving and making available the historical data, setting and viewing of the current automatic control values transmitted by OSP. DOI: 10.12736/issn.2300-3022.2015109 1. General information, design requirements and short description of the LFC system LFC is a currently implemented, by PSE Operator SA, standard of the automatic frequency and power control system, the objective of which is the real-time operating and monitoring of the power generating units operated in the Polish electric power network, defined by the name of the centrally disposed generating units (Jednostki Wytworcze Centralnie Dysponowane (JWCD)). The LFC system is the successor of the SOWE system; it operates in a distributed environment, integrating into the available networks, JWCD, and realising the controls of the central controller of LFC (RC LFC). Each JWCD is autonomous in the LFC network and participates in the automatic power control process when it is officially admitted, by OSP, for operation in the production environment of LFC. The global system “intelligence” is wired in the central controller component, the basic task of which is to maintain the balance between the power produced and the current demand for it within KSE. RC LFC communicates with a power plant via the local node of the LFC system (WL LFC). The local node integrates various technological solutions applied on the facility site so that it is transparent for RC LFC. It conducts the direct or indirect dialogue with the unit automation, realising the controls from RC LFC and transferring back to WC SMPP the current values and the operating parameter states of JWCD. The official specification of WL LFC defines very precisely the way of conduction of the communication in the relation OSP WL LFC (the ICCP-TASE.2 protocol), but it does not impose any specific design solutions with respect to the communication of WL LFC with the automation systems of JWCD. The diversity of the technological solutions on the facility side translate directly into the complexity of the LFC local node implementation. The integration process of SRM LFC with the existing solutions is not trivial and requires the cooperation of all enterprises involved, in order to build a reliable infrastructure interconnecting each JWCD with RC LFC. The design requirements set for the local nodes have been made more precise by PSE Operator SA in two documents entitled ”Wymogi wobec JWCD na potrzeby wdrazania systemu LFC” (The requirements for JWCD for the purposes of implementation of the LFC system) and ”Procedura odbioru wezlow lokalnych systemu LFC w elektrowniach” (The procedure of acceptance of the local nodes of the LFC system). The following may be rated among the most important design goals of OSP: • high operational reliability of action of the whole system • provision of the redundancy of the hot spare type • fast switching between the master/slave modes of the SRM server instances D, Wojtanowicz et al. | Acta Energetica 1/22 (2015) | 121–127

Design of a Prototype of Water Purification by Plasma Technology as the Foundation for an Industrial Wastewater Plant

In order to mitigate the contamination of water sources due to the spill of sewage without any kind of treatment, mainly generated by the industrial sector; a prototype of water purification by plasma technology has been designed. The prototype will transform liquid water into plasma to eliminate the pathogens from the water, due to their exposure to ultraviolet radiation, electric fields and shock waves, which aid in the destruction of pollutants. The sewage will be accelerated at high speed to convert it into a liquid-gas mixture in order to transform it into plasma, which is achieved when the electrical discharge (of the type dielectric barrier discharge or DBD) is applied to the water by means of high voltage electrodes, from a source of alternating current (AC). Subsequently, the mixture slows down to be return into liquid phase and obtain clean water, all of these without a significantly rise of temperature. The device also has an automatic power control system. Finally, a short feasibility study was conducted in order to use this type of water cleaner in the future as a basis for a treatment plant of industrial waste water, so it comes to replace the current secondary and tertiary treatments used among the industry. It is intended that this new system will be more efficient and cheaper than the current waste water treatments.

Узагальнена математична модель та характеристики адаптивних систем автоматичного регулювання частоти і потужності

Узагальнена математична модель та характеристики адаптивних систем автоматичного регулювання частоти і потужності