Power Plant Unit Research Articles

Numerical investigations of protective shells of NPP evergy units with pressurized water reactor (VVER)

Most of the energy units of nuclear power plants in Ukraine are at the stage of exhausting their design lifespan. Therefore, the issue of extending the lifespan of energy units of nuclear power plants (NPP) and, consequently, assessing the residual life of protective shells is very acute. State Enterprise "The State Research Institute of Building Constructions" developed universal computer models of NPP energy units from VVER-1000 type V-302 and V-338, taking into account all the design features of protective shells, load connections and the possibility of varying the level of pre-tensioning of ropes. The developed models made it possible to evaluate the operability of a localizing safety system - a hermetic enclosure system in all operating modes, including a combination of loads during a design basis accident and a maximum design earthquake. The purpose of this work is: on the basis of numerous studies of the load-bearing capacity of the protective shells of energy units in all operating modes, to develop a methodology for determining the rational tension of the ropes in rows, at which the forces in the ropes of all three rows under the action of emergency load coupling during normal operation plus design basis accident plus the maximum design earthquake (NO + DBA + MDE) is distributed most evenly and, as a result, the probability of breaking the ropes of the outer row during an accident is reduced.
 As a result of numerous studies of the load-bearing capacity of the protective shells of energy units in all modes of operation and the determination of the rational tension of the ropes in rows under the action of NO+DBA+MDE, the following has been established: minimum allowable tensile force of reinforcing ropes in the cylindrical part of the protective shell of the energy unit in the absence of two ropes; minimum allowable tensile force of reinforcing ropes in the cylindrical part of the protective shell of the energy unit in the absence of three ropes. The rational distribution of rope tension between the rows is determined, in which the efforts in the reinforcing ropes of all three rows under the action of NO+DBA+MDE are distributed most evenly and, as a result, the probability of breaking the ropes of the outer row in case of an accident is reduced.

Expert express assessment of the impact of heat and mass transfer processes on the residual life of the WWER-1000 reactor vessel due to cyclic damage

Ukraine remains a country dependent on nuclear energy for both heat supply and satellite supply. In cities close to nuclear power plants, electric heating from the electricity they produce is appropriate. On the other hand, Ukraine is the only country in the world where the worst accident at a nuclear power plant occurred at the Chernobyl NPP Unit 4 on the night of April 26, 1986. Another characteristic feature of Ukraine's nuclear energy is the significant number of power units with exhausted project resources - the so-called "old" power units. Their wear is associated with the influence of heat and mass transfer processes, which lead to periodic thermal deformation of the elements, which causes cyclic damage. An example of expert rapid assessment of the residual life of a specific reactor vessel WWER-1000 is given taking into account the combined action of non-stationary heat and mass transfer and mechanical processes. A detailed express calculation of cyclic (tired) damage to the metal of the WWER-1000 reactor vessel due to the dangerous emergency mode has been performed. The WWER-1000 reactor is the last most widespread and most powerful water-water nuclear reactor of the former USSR, operated on 13 of the 15 operating power units of Ukrainian nuclear power plants (NPPs) - Zaporizhia, Rivne, Khmelnytsky and South Ukraine (SUNPP). The reactor is the most important indispensable element of a nuclear power plant, which determines its safety and resource. Given the design resource and the dates of commissioning of Ukrainian NPP units, the issue of rapid expert assessment of the technical condition of WWER-1000 hulls is quite relevant. Of course, modern engineering has the full range of tools needed to perform such estimates, from powerful computers to advanced computing software. But the known and inevitable costs of modern engineering - complex and time-consuming modeling and calculations. Experience has shown that a certain "reasonable" combination of the use of relatively simplified "light" calculation methods allows us to assess the safety, strength and service life of WWER-1000 reactors very quickly and with the necessary accuracy acceptable for expert opinion. The publication considers as an example the real emergency situation of October 22, 1985 and the WWER-1000 reactor of SUNPP Unit 1. Since this emergency situation led to rapid cooling of this reactor, the calculation of the effect of cyclic damage of reactor steel on the strength and reliability of the reactor vessel is shown. This example and the consideration of the real emergency situation demonstrates the effectiveness and acceptability of the use of estimated expert rapid assessments to accurately determine the reliability and safety of such critical elements of nuclear power plants as nuclear reactor buildings.

On the Problem of Sequential Traversal of Megalopolises with Precedence Conditions and Cost Functions Depending on a List of Tasks

A constrained routing problem with complicated cost functions is studied. The construction of the cost functions can be difficult, and therefore the stages of this construction are elements of the solution of the problem. This situation arises, in particular, in studying the engineering problem of dismantling radiation hazardous elements, where, in the framework of a problem statement traditional for discrete optimization, it takes an unacceptably long time to construct a cost matrix whose entries characterize the radiation doses received by performers at the stage of displacement and dismantling. It is assumed that, at the stage of the computational implementation of the resulting optimal algorithm, the corresponding “parts” of the matrix may be not fed to the computer’s memory but calculated as needed. Possible applications of the developed methods may be related to the problem of dismantling a decommissioned generator unit of a nuclear power plant.

Ways to Increase the Durability and Reliability of Functional Units of Automotive Equipment

The operation of the engine in optimal temperature conditions provides the possibility of obtaining the highest indicators of its efficiency, namely, maximum output power; minimum fuel mixture consumption; increase in effective service life; increase in the reliability coefficient. (Research purpose) The research purpose is to substantiate the indicators for evaluating the efficiency of cooling systems of functional units used on automotive equipment. (Materials and methods) The introduction of surfactants with a fluorocarbon radical into the engine oil leads to an improvement in the operational characteristics of the functional units of machinery and power plants (power, specific fuel consumption and others), which is due to a decrease in hydrodynamic friction. (Results and discussion) When adding an antifriction additive to the engine oil, there is an increase in engine power and torque by 2.5-3.0 percent; reduction of specific fuel consumption by up to 6.9 percent, hourly fuel consumption by 3-4 percent; reduction of carbon dioxide emissions, improvement of fuel efficiency in the urban cycle by 2.6 percent, in rural by 2.8 percent, in mixed by 2.7 percent, reduction of acceleration time in the speed range of 80-130 kilometers per hour by 2.8 percent. (Conclusions) The organization of cooling processes of working units and heat carriers of their systems should be carried out taking into account the mutual influence of these components. This approach allows for the reconstruction of cooling systems both at the final stages of design and during operation. For the functioning of auxiliary cooling systems and the improvement of heat exchange, a detailed study and analysis of the operational processes of agricultural machinery are necessary. The creation of the most efficient cooling systems and conducting research using various lubricants requires consideration of the temperature- dynamic properties of cooling systems, taking into account the patterns of changes in their temperature modes and lubrication of functional systems depending on operating conditions and the environment, which will allow to identify the parameters of reliability of operability.

Operational Parametric Based Reliability Estimation & Justification of Failure Criterion of Hydro Power Plant: A Case Study

Abstract: Generating more Power are complex at cheaper cost, also continuous energy supplied are important Hydro power generation is one of the most successful renewable energy resources for the production electrical energy without any environmental hazard and presently it providing more than 86% of all electricity generated by renewable sources worldwide and accounts for about 20% of world electricity. To increase the percentage of green energy in account of world electricity generation the analysis must be performed to get the information about the working conditions of each component in plants so that the required maintenance action should be taken. Maintenance and operation of a hydro power plant is very complicated and the process to calculate and analyzing its compatibility and reliability is very important. In this work introducing a Markov model to evaluate the reliability parameter of THPS-I Sirmour, Rewa. For this work the operational data regarding failure and maintenance time taken to repaired and analysis of all parts of generating unit of the power plant for period of 2010-2015 is considered. The availability and reliability of individual unit of power plant is evaluated by taking into account different reliability Parameters, namely failure rate (λ), repair rate (µ), MTTR, MTTF, MTBF through the collected data and tabulating the required information for the analysis. By this analysis work we can improve reliability of all the components of each unit of power plant. The sub-unit that is commonly failed during operation is like- penstock, butter fly valve, spiral case, turbine, generator, excitation system, speed governor etc. Reliability plays a key role in the cost-effectiveness of systems Keywords: Hydro power plant, Reliability evaluation, Reliability parameters, Markov analysis, Total schedule outage hrs and Total forced outage hrs.

Удосконалення управління процесом горіння палива в суднових котлах

Annotation – The article discusses the issues of increasing the efficiency of the combustion of liquid fuel in the furnaces of ship steam boilers using the proposed neural network system for automatic correction of the excess air coefficient. It is indicated that modern systems for automatic flame detection have a number of disadvantages, in particular, low sensitivity to extraneous illumination, etc. hot air or flue gases on the walls of the boiler furnace. Such pulsations reduce the reliability of the combustion monitoring and control system. Therefore, the task of developing and introducing on ships new, economically inexpensive and effective methods of effective control and management of the fuel combustion process in ship boilers using modern means of intelligent control is urgent. On the basis of the experiments carried out on a Mitsubishi MV 50 marine steam boiler and the collected experimental data, the values for training the neural network system of the air flow correction process, taking into account the color of the burner flame and the color of the flue gases, were obtained. The use of a trained neural network in the control system, taking into account the fuzzy expert system for monitoring the color of the flame and smoke, makes it possible to achieve the best excess air ratio depending on the steam load of the SEP units. Simulation modeling of the proposed neural system was carried out in a specialized program Matlab (Neural Networks Toolbox). The simulation results showed that the use of a neural network control system for the combustion of liquid fuel, using the example of a marine boiler, allows maintaining a given thermal regime over the entire range of steam load of the power plant units, and also allows timely correction of the excess air ratio, i.e. avoid excessive consumption of fuel.

Mathematical modeling of the thermochemical processes of sequestration of SOx when burning the particles of the coal and wood mixture

The article presents the results of mathematical modeling of the initial stage of the combustion of wood and coal particles in conditions corresponding to the combustion chambers of boiler units of thermal power plants. A hypothesis is formulated that describes the sequestration of anthropogenic sulfur oxides (SOx) under the conditions of combustion of mixed fuels based on coal and wood as a result of the interaction of water vapors (formed during the evaporation of interporeal and adsorbed biomass moisture) with SOx with the formation of sulfuric (H2SO4) acid vapors. When these vapors of sulfuric acid H2SO4 interact with iron oxides of the mineral part of the coal. To test the formulated hypothesis, a new mathematical model has been developed for the processes of co-ignition and combustion of wood and coal particles under high-temperature heating conditions. The mathematical model of the ignition process developed by the authors differs from the known ones (published in leading international scientific periodicals on the combustion of solid fuels) by a detailed description of a complex of gas-phase and heterogeneous thermochemical reactions occurring both in the boundary layer of fuel particles and in their porous structure. The mathematical model of the combustion process of wood-coal fuel particles developed by the authors is currently the most detailed in describing the thermophysical, thermochemical and aeromechanical processes occurring both in the fuel particles and in their small vicinity. Multistage kinetic schemes for the oxidation of the main volatile components (methane ‒ CH4, carbon monoxide ‒ CO, hydrogen ‒ H2), as well as the formation of sulfur oxides by means of oxidation of hydrogen sulphide (H2S), released as a result of pyrolysis of the organic part of coal, have been adopted. Based on the results of numerical modeling, the possibility of intensifying the processes of sequestration of sulfur oxides by moistening the wood component of the fuel mixture has been established. It is shown that water vapor can act as an agent adsorbing anthropogenic sulfur oxides, transforming the latter into sulfuric acid vapor, respectively. In turn, the vapors H2SO4 and HNO- 3 can be relatively easily captured by means of condensation. It has been established that for effective SOx capture during co-combustion of coal and biomass, the moisture content of the latter must be at least 5% by weight. The research provides grounds for the conclusion about the possibility of environmentally efficient combustion of coal in the composition of wood-coal fuel composites.

Performance and boiler efficiency using low-grade coal on 400 MWe coal-fired power plant: case study of Suralaya Power Plant Unit 2

In a coal steam power plant, changes in coal quality significantly affect plant performance, especially in its boiler. A coal-fired power plant with a capacity of 400 MWe had been commissioned using coal with a calorific value of 5,242 kCal/kg. This study aims to determine the effect on unit performance and boiler efficiency due to changes in fuel use with the typical calorific value of 3,520 kCal/kg, 34,17% lower than the initial design. The performance tests were conducted using the heat loss method at loads: 50%, 65%, 75%, and 100%. The test result showed that using low-grade coal reduces boiler efficiency by 6.26%. There were four dominant boiler losses: heat loss due to moisture in dry flue gas, heat loss due to combustible in refuse, heat loss due to moisture in fuel, and heat loss due to hydrogen burning. Furthermore, the gross plant heat rate using low-grade coal was increased from 2,120 kCal/kWh to 2,718 kCal/kWh; however, the electric price becomes cheaper from 1.99 cent-USD/kWh becomes 1.31 cent-USD/kWh.

Development and verification of methods for predicting the frequency of self-oscillations in swirling coolant flows of nuclear power plants

Methods and algorithms for calculating the frequency of self-oscillations in swirling coolant flows of nuclear power plants with VVER reactors have been developed. The frequency of self-oscillations occurring in the acoustic sections of the primary circuit and their connections in the starting modes of the power unit and when operating at the rated power level is predicted. It is established that the self-oscillation frequencies can fall into the frequency bandwidth of mechanical vibrations and vibrations of the reactor plant’s internal devices. It is shown that in order to prevent the resonance of self-oscillations of the coolant with the vibration frequencies of internal devices, it is necessary and sufficient to take the frequency of self-oscillations outside the bandwidth of the vibration frequency of structures. The results of verification of the results of forecasting the frequency of self-oscillations in swirling coolant flows at a nuclear power plant unit with VVER are presented. The application of the developed technique shows that the pendulum oscillations of the VVER - 1200 body are caused by an increase in the parameters of the coolant and the geometric dimensions of the VVER - 1200 reactor compared to VVER-1000.

ANALISIS PERFORMA MENARA PENDINGIN MECHANICAL INDUCED DRAUGHT ALIRAN COUNTERFLOW PADA PEMBANGKIT LISTRIK TENAGA PANAS BUMI LAHENDONG UNIT 5

In the geothermal power plant process, the main cooling water system is required to maximize the power plant, one of them is using the cooling tower. The Cooling Tower is an incredibly vital cooler. So, the performance must be noted is still in accordance with initial conditions. The purpose of this research is to determined the performance of Mechanical Induced Draught counterflow Cooling Tower in Lahendong Geothermal Power Plan Unit 5 with quantitative research for 7 days with 10 hours of operational work. In Lahendong Geothermal Power Plant Unit 5. The result of this research showed the performance of Mechanical Induced Draught Counterflow Cooling Tower in Lahendong Geothermal Power Plan Unit 5. The range increased up to 14.2 C, in the morning because of the high humidity, the effectiveness which also increases in the morning and the airflow conditions which still remain. So, this research will be concluded when the performance of Mechanical Induced Draught Counterflow Cooling Tower Geothermal Power Plant Unit 5 is still in normal operation conditions and needs to do Make-up Water amounts of 387.81 m3/h.

Strategic Planning for Carbon Capture and Storage Implementation in the Electricity Sector of Greece: A TIMES Based Analysis

This paper presents a roadmap performed in 2010 as part of a European project for the modelling of carbon capture and storage technology, and various scenarios with different taxations and permit prices for the CO2 emissions considering the Greek national plans, then the gradual decommissioning of various lignite or other units of electricity power plants. In addition, this study presents a first check, 10 years after its writing, of the current situation of the Greek energy system, regarding the correspondence of the roadmap designed in 2010 to what has been finally executed during this period, including the possibility of other energy sources complimenting or substituting the national strategic energy plans. For this purpose, the integrated MARKAL-EFOM system (TIMES) was employed to model the Greek energy system and evaluate its development over time, until 2040, by analyzing three different scenarios with respect to taxation and permit prices for carbon emissions. The results obtained show that, if this study had been considered and executed by the different stakeholders during that period, then the implementation of CCS in the new licensed power plants from 2010 and onwards could reduce the use of lignite and imported hard coal power production in a much smoother and beneficial way in the next years, and until the present, without compromising any major power plants. This implementation would also make the transition to a lignite free economy in Greece much faster and better, while complimenting the EU regulations and also enhancing the possible greater use of alternative energy sources in the green energy mixture.

Diagnosis of the Static Excitation Systems of Synchronous Generators with the Use of Hardware-In-the-Loop Technologies

In this paper, testing and diagnosis methods for the static excitation systems of power plant synchronous generators using Hardware-In-the-Loop technology are described. These methods allow a physical excitation system to be connected to a real-time model of a power plant unit. A feature of a static excitation system is the presence of generator self-excitation—that is, when the input voltages of the excitation system are defined by a synchronous generator. These voltages are determining by the digital model, which creates additional difficulties with combining a digital model with a real excitation system. Various ways to solve this problem are described in this article; in particular, we focus on the option in which the gate-impulses of a thyristor converter are applied to the digital model by a real static excitation system. The real-time models are based on the method of average voltages in the integration step. This method is effective for providing numerical stability for the models of power schemes and their functioning in real time mode over a long period. A synchronization method for the calculation time of the model with real time is described. The adequacy of the described method is proved by the results of the static excitation system of synchronous generators testing in operating and fault modes.

Optimization of Gas Turbine Component Maintenance to Improve Reliability of Power Plant Industries

he thermal power plant unit in Java is PLTGU Z with 3 blocks consisting of 9 gas turbines, and 3 steam turbines with a total installed capacity of 1578.78 MW. One of the problems faced is a high component failure rate, decreased system reliability, and an impact on rising maintenance costs. The method to be implemented in order to maintain the achievement of power plant performance and reliability of generating units is to optimize equipment reliability. Periodic component replacement is one way to maintain the reliability of the unit, where current conditions do not yet exist as a standard that is specifically used as a basis for the component replacement activities. For this reason, optimization of component replacement is required by considering the value of reliability, equipment downtime, frequency of replacement time, and costs required. It is intended that the reliability of the equipment is achieved at the optimum cost. The first stage is to identify the reliability value based on the failure data using Weibull ++ 6 software, then adjusted to the system reliability target in accordance with company standards. The second stage performs calculations to determine the minimum time of downtime and minimum preventive maintenance costs in a period of time. The third stage is determining the optimization of equipment reliability and the consequence of the required cost increase according to the system reliability target. After optimizing the reliability of the system with a target value of R(G) = 0.7 the optimization results obtained with the longest preventive maintenance intervals on gas nozzle equipment every 8000 hours, and the shortest maintenance time intervals are found on the fuel gas system equipment that is 40 hours.

Automated Analysis of Service Life of Air-Lines of the Electricity Transmission of Electric Power Systems

Basic EPS objects, which service life has exceeded normative value, increasingly affect – every year to a greater extent – the efficiency of overall performance. This manifests itself in increase of a number of automatic emergency shutdowns, an amount and complexities of accident-hazardous defects. After the expiration of the standard service life, there is a special need for a quantitative assessment of reliability and safety of an object. It is recommended to organize the operation, maintenance and repair of these objects according to their technical condition, and since it determines the reliability and safety of the object, these properties should be taken into account more fully. The relevant recommendations in electric power systems are implemented at a qualitative level, intuitively, according to the operating experience. There are neither quantitative evaluations nor methodology for their performance. Therefore, a method and algorithm of quantitative assessment of integral indicators of reliability and safety of operation of thermal power units of thermal power plants as concentrated objects of continuous operation were previously analyzed by the authors. The present paper examines distributed objects of continuous operation, viz. overhead power transmission lines with a voltage of 110 kV and higher, whose service life exceeds the standard value. Attention is paid to the issues of quantitative assessment of the degree of aging for a set of overhead power transmission lines, classification of these lines to identify the most significant classes and methodology for assessing the difference in the degree of aging when classifying them according to specified types of signs (for example, the difference in the degree of aging of overhead power transmission lines of grid enterprises of electric power systems). It is shown that it unacceptable to use the estimates of the relative number of overhead power transmission lines, the service life of which exceeds the calculated one, for comparison since it causes a great risk of an erroneous decision. The methodology and algorithm of methodological support of the management of electric power systems and grid enterprises in the organization of operation, maintenance and repair have been developed.

Comparison of Cooling Systems in Power Plant Units

A new porous system in power plants allowing the management of the crisis of heat exchange at boiling water in porous structures has been investigated. This study refers to the thermal power plants of electrical power stations and devices for cutting natural and artificial mineral media. Combustion chambers and supersonic nozzles were cooled by different porous structures. The optimum cell sizes of the porous structures were determined and data on the heat transfer capacity for the (critical) heat flow were obtained. A thermal device in the form of a rocket-type burner with a detonation jet showed high efficiency for capillary-porous and flow-through cooling systems. The economic effect per burner is not less than 200–300 dollars, and the coolant consumption is reduced by dozens of times, which is environmentally important. A comparative evaluation of the investigated structures and coatings has advantages over other cooling systems. The integration of mesh structures with capillary-porous coatings of natural mineral media produces a synergistic effect of combining them into a technology of their manufacturing, the expansion of critical loads removal and control of the limit state of the coatings.

COMBINED POWER PLANT OF A MOTOR VEHICLE

Currently, the most promising areas of development of motor transport are an increase of the horsepower characteristic of their power plants as well as increase of fuel efficiency, and reduction of the toxicity level of exhaust fumes. An internal combustion engine as a power unit of the car in a number of operation modes (supplemental motion, small work load, idling, etc.) works extremely inefficiently and contains the high concentration of harmful components in the exhaust fumes. Additionally, in a context of growing shortage of carbohydrate fuels and increase in their value, the problem of the fuel-burn improvement is especially acute. To improve the environmental compatibility and efficiency of power plants of the vehicles, combined cycle power plants are used. One of the most important problems that the machine construction faces is the creation of environmentally friendly and economical power plants. A hybrid power plant, which contains several power units operating on different physical principles, is proposed by the authors. The main power unit uses the energy of liquid or gaseous fuel in the mode of an internal combustion engine; the auxiliary power unit which is made as a reverse volumetrical driving machine with swinging motion of the work tools (forcers or blades), uses air power which comes from a pneumocylinder through a cooler and / or pneumatic air tank. The auxiliary power unit is equipped with a reversible invertor of the driving direction, made on the basis of a spherical slider-crank mechanism. This insures the operation of the auxiliary power unit in the mode of a pneumatic motor or compressor in accordance with the algorithm generated by the electronic control unit of the combined power plant of the vehicle. To utilize the heat energy of the exhaust fumes of the main power unit, the combined power plant is additionally equipped with a Stirling engine or steam generation module and a steam engine; in order to break energy recuperation of the vehicle it is additionally equipped with a hydraulic or electrodrive. Naturally, when choosing the specific forms of application of combined cycle power plants, any combinations of auxiliary power units are possible. They can be supplemented and / or specified based on the knowledge of specialists. Combined cycle power plants are technically complete solution. Their industrial applicability is obvious and is substantiated by experiments. Nowadays, the creation of a combined cycle power plants of a vehicle, which are a combination of several engines operating on different physical principles is the task of great economic importance. Combined power plants this allows to reduce fuel consumption per 100 km significantly, increase energy potential, horsepower characteristic and improve the environmental performance of the vehicle. The work is planned to be continued in the direction of optimization synthesis of auxiliary power units that work on different physical principles.

Investigating the hydraulic resistance in the flow part elements of pneumatic systems and heat exchangers

The article deals with the development of shell-and-tube heat exchangers for the needs of power engineering, based on additive technologies, in particular, selective laser sintering technology with new configurations of heat exchange surfaces. The role of heat exchangers in microturbines, the most common units of power plants of small distributed power generation, is considered. To intensify heat transfer and increase the efficiency of microturbines, it is proposed to use various configurations of flow channels of shell-and-tube heat exchangers made on the basis of additive technologies. Mathematical modeling and experimental study of a gas medium flow in the tubes of a heat exchanger are carried out. The dependences of the coefficient of hydraulic resistance between the surface of inlet and outlet of gas from tubes of various configurations on the Reynolds number are obtained. The results of the experiment allow us to conclude that the resistance of spiral-shaped tubes is slightly higher than the resistance of tubes with three ribs.

Design And Control System of Automatic Control System of Coal Flow on Belt Conveyor Installation

In a power plant unit whose main fuel is coal, there is generally use a belt conveyor installation. This conveyor belt serves to supply coal from the crusher unit to the combustion chamber of the power generation unit. In this study, we discuss a case where the installation of a belt conveyor which was initially only one line was then made a new branch that supplies coal to other power generating units. Equitable capacity distribution and continuity of coal distribution are the main focus of this study. Therefore, a design of automatic control system of coal flow divider on belt conveyor installation was designed. The working principle of this coal flow splitting system is to control the movement of the straight blade plough that directs the flow of coal to each unit at the certain time and continuously. Straight blade plough in the form of steel metal plate with a thickness of about 10 millimeters in which one end is connected to the end of the pneumatic cylinder. Automatic control system of coal flow divider in belt conveyor installation designed using CX-Programmer and CX-Designer applications. CX-Programmer serves to create automatic control logic concepts. While the CX-designer functions to create a Human Machine Interface (HMI), making it easier for operators to control the course of the coal supply process. The results of this study are in the form of control logic lines that can be applied to Programmable Logic Control (PLC) device and Human Machine Interface (HMI) equipment.

Optimal Coordination of PSS and SSSC Controllers in Power System Using Ant Colony Optimization Algorithm

Volatility leads to disruption in synchronism between generators of a continuous system. The frequency of the volatility is usually between a few tenths of Hz to several Hz. This volatility is sometimes divided into two types, local and interregional. Local volatility is the low-frequency volatility of a power plant unit or units of a power plant relative to the grid whereas interregional volatility is the volatility of the units of one area relative to the units of another area. The worst kind of low-frequency volatility occurs when the power system in a region has a short three-phase connection to the earth, creating a complete instability of the grid and operating protective systems. One of the ways to improve the dynamic stability and steady-state of the power system is to use power system stabilizers and FACTS devices in the system. In this paper, the stabilization of the power system stabilizers (PSSs) and SSSC is done using the ant colony algorithm. Studies on a four-machine system with the three-phase error were performed in two scenarios and finally compared with the PSO method. The simulation results show that the proposed method produced more accurate performance.

Performance Assessment Analysis in Selecting The Best Employees Maintenance Department in PT. PJB UBJOM PLTU Tanjung Awar - Awar with Analytical Hierarchy Process (AHP) Method

PT. Pembangkit Jawa-Bali (PJB) is a company engaged in the electricity supply service business. PT. PJB also has another business unit, namely the Operation & Maintenance Service Business Unit (UBJOM) which provides operation and maintenance services for power plant units, one of which is PT. PJB UBJOM PLTU Tanjung Awar - Awar. PT. PJB UBJOM PLTU Tanjung Awar - Awar won the trust of PT. PLN to handle the performance of the Operation & Maintenance of power plants for the Energy Diversification Acceleration Program (PPDE) with a capacity of 2 x 350 Mega Watt (MW). PT. PJB UBJOM PLTU Tanjung Awar - Awar consists of 5 departments, namely the Operations Department, the Maintenance Department, the Engineering Department, the Logistics Department and the Finance and Administration Department. In an effort to improve the quality of good human resources, so as to increase the productivity of a company. In order for the quality of employees to be maintained and improved, the company needs to conduct an employee performance appraisal in the form of selecting the best employees where employee performance can be appreciated by the company in order to achieve mutual progress. By using the Analytical Hierarchical Process (AHP) method as a suggestion in the objective performance appraisal so that the rank-ing7 criteria for staff judgments from the highest to the lowest are Discipline with a weighted value of 0.424, then Personality with a weighting of 0.290, Work Results with a value weight of 0.175, and Work Relationships. with a weighted value of 0.111. It was found that the order of staff with the greatest value was Rank 1: Trio Arta, Rank 2: Teguh Indra, Rank 3: Ade Wahyu, and Rank 4: Nizar Setiawan. So that the best staff selected in the Maintenance Department at PT. PJB UBJOM PLTU Tanjung Awar-Awar