Turbine-generator Units Research Articles

Efficient allocation of energy storage and renewable energy system for performance and reliability improvement of distribution system

This paper aims to investigate the impact of optimal planning of renewable energy systems and independent battery energy storage systems (BESS) on the performance and reliability of distribution systems (DS). A unique energy management scheme (EMS) controls the charging and discharging schedules of the BESS. The transit search optimization (TSO) algorithm determines the optimal allocation of wind turbine (WT) and solar photovoltaic (SPV) generator units, along with BESS units. The optimization focuses on improving the DS reliability in terms of energy supply, increasing the feeder security margin, and reducing apparent power loss. Multiple case studies are designed to study the efficacy of the problem outcomes and are validated using Bus 4 of the Roy Bollington Test System (RBTS). To obtain results that are close to actual operating conditions, the modelling process takes into account the time-varying load profile and the dynamic power outputs from the SPV and WT units. The findings show that the suggested method works well by enhancing the feeder security margin by a maximum of 11.25%, reducing expected energy not supplied (EENS) by 4.3%, and improving the power loss profile by 11.5%. In addition, the feeder upgrade deferral (FUD) years also show a maximum improvement of 20.8%.

Voltage Sag Reduction by ANFIS in Wind Turbine Generation Units

Voltage Sag Reduction by ANFIS in Wind Turbine Generation Units

Research on fault diagnosis of main equipment based on watershed power production data center

Abstract With the development of intelligent hydroelectric power stations and centralized control centers, water and hydropower development companies in various river basins have constructed power production data centers, establishing standardized and normalized data models and connecting the underlying system channels. Based on the power production data center, this paper constructs a unified data model for monitoring the main equipment and, in response to the shortcomings of the existing equipment alarm mode, analyzes the advantages of expert knowledge and intelligent diagnostic methods. It establishes a comprehensive diagnostic system for the main equipment of power stations, providing multi-level and multi-perspective diagnostic reference opinions. This system is of great significance for promoting the development of intelligent hydroelectric power and centralized control. Finally, taking the operating condition data of a mixed-flow turbine generator unit as an example, the effectiveness of the comprehensive diagnostic model is analyzed and verified.

Investigation of Lateral Vibrations in Turbine-generator Unit 5 of the Inga 2 Hydroelectric Power Plant

The article presents a case study on the Investigation of lateral vibrations in the turbine-generator unit 5 of the Inga 2 hydroelectric power plant in the Democratic Republic of the Congo. Lateral vibrations were experimentally determined using twelve proximity and eddy-current probes, positioned on each measurement plane. The results were analyzed using the Dasylab and R software. Hence, it was observed that the vibration amplitudes of the upper guide bearing, lower guide bearing, and pivot/rotor exceeded acceptable or critical limit values of the international vibration standard for a rotating speed between 100-250 rpm. These excesses can lead to rotor mass imbalances, the eccentricity of the rotor axis relative to the rotation axis of the shaft, and the deformation of the coupling shaft between the upper rotor shaft and the turbine rotor shaft. Subsequently, the means and the variances of the vibration amplitudes were evaluated and compared to the reference values of the international standard. The results of the compliance analysis revealed statistically significant differences between the measured amplitudes and the reference values. Thus, it indicates deviations from international specifications.

Power System Analysis of Steam Power Plant Using ETAP at ULPL Indralaya South Sumatra

PT PLN (Persero) UPDK Keramasan have three group work units in South Sumatra Province which is study has located in Ogan Ilir Regency namely PT. PLN ULPL Indralaya. This study is one steam turbine generator unit often experiences shutdown due to several factors. One of them is out of service for the protection operating system on the 4 MVA to 11.5/6.9 kV transformer unit when there is a disturbance so that there is an inter-trip to the upstream system which results in a blackout system. We analyzed the disturbance using ETAP software. We made three analyzes there are load flow, short circuit and relay coordination. As study results submitted to PT PLN ULPL Indralaya is to scenario 3 for the analysis of the resulting lower flow is a decrease in load of about 63% for short circuit value obtained between 0.011 to 50.776 kA also relay coordination should be adding devices such as IDMT curve Long Time Inverse.

Application of deep learning modelling of the optimal operation conditions of auxiliary equipment of combined cycle gas turbine power station

Reasonable condition adjustment of the auxiliary machinery can optimize the operation performance of the Combined Cycle Gas Turbine (CCGT) power station. In this paper an optimization method for the operation control of the auxiliary equipment based on deep learning is proposed and applied to an F-class gas turbine generation unit. A database of the optimal operating conditions is established to achieve the best economic benefit based on the analysis of two years of historical operation data. The control optimization models are built using the machine learning algorithms including the Multi-Layer Perceptron (MLP), Supporting Vector Machine (SVM), Gaussian process regression and linear regression methods and their accuracy has been compared. The input parameters of these models consist of the load rate, the heating output and the ambient temperature, with the output parameters including the electrical currents for the mechanical draft cooling tower, the high pressure feed pump, the medium pressure feed pump and the condensate pump. The MLP model is designed with different network hidden layer structures and provides the highest calculation accuracy with the least average error of 1.82 %. Different training data sizes are compared and the optimal control trajectory is analyzed. The result can provide useful references for the optimization of auxiliary equipment operations.

Turbo generator vibration source identification based on operational transfer path analysis technology

Unstable vibrations in rotating machinery can stem from various causes, making it challenging to determine their origins. This research introduces the operational transfer path analysis method (OTPA) as a means to identify the causes of turbo generator vibrations. The model takes operational parameters, such as power and current, as input, and the vibration amplitude as output, to establish the source analysis model. To address the ill-conditioned input matrix, the singular value decomposition method is employed. By solving the transmissibility matrix and analyzing parameter contributions, the primary factors influencing vibration are identified. This method is applied to analyze the vibration sources in a 660 MW turbine generator unit. The generator experienced unstable vibration of unknown origin for a certain period. Operational transfer path analysis revealed that hydrogen pressure, hydrogen temperature, and bearing temperature significantly impacted the vibrations. Thermal imbalances and shaft misalignment in the generator rotor were inferred as the likely causes. Through adjustments to hydrogen pressure and temperature, the generator vibration was controlled until the next overhaul. Subsequent maintenance revealed partial blockage of the hydrogen ventilation holes, leading to rotor thermal imbalances. The feasibility of this method was confirmed. The objective of this study is to present an effective data-driven model for identifying the main influential parameters among numerous variables. This model can be applied to intelligent fault diagnosis in power generation units.

Hybridization of a RoR HPP with a BESS—The XFLEX HYDRO Vogelgrun Demonstrator

In the XFLEX HYDRO Vogelgrun demonstrator, a run-of-river hydropower plant, the hybridization of one turbine-generator unit with a battery energy storage system is being investigated. This paper describes the integration methodology of the hybrid control algorithm without replacing the existing speed governor of the unit. Furthermore, the comparison of the performances of a non-hybrid and hybrid unit is discussed, and first experiences gained during the operation and monitoring of the hybrid operating mode are presented.

Frequency Regulation of Interlinked Microgrid System Using Mayfly Algorithm-Based PID Controller

The primary goal of this article is to design and implement a secondary controller with which to control the system frequency in a networked microgrid system. The proposed power system comprises of Renewable energy sources (RESs), energy-storing units (ESUs), and synchronous generator. RESs include photovoltaic (PV) and wind turbine generator (WTG) units. The ESU is composed of a flywheel and a battery. Because renewable energy sources are not constant in nature, their values fluctuate from time to time, causing an effect on system frequency and power flow variation in the tie line. The nonlinear output from the RESs is balanced with the support of ESUs. In order to address this situation, a proportional integral derivative (PID) controller based on the Mayfly algorithm (MA) is proposed and built. Comparing the responses of controllers based on the genetic algorithm (GA), differential evolution (DE), and particle swarm optimization (PSO) technique-optimized to demonstrate the superiority of the MA-tuned controller.. The results of the validation comparisons reveal that the implemented MA-PID controller delivers and is capable of regulating system frequency under various load demand changes and renewable energy sources. A robustness analysis test was also performed in order to determine the effectiveness of the suggested optimization technique (1%, 2%, 5%, and 10%) step load perturbation (SLP) with ±25% and ±50% variation from the nominal governor and reheater time constant).

Exergy and Energy Analysis of Gas Turbine Generator X Combined Cycle Power Plant Using Cycle-Tempo Software

Increasing electricity production must continue to be pursued to meet the increasing electricity needs of the community. One of the efforts that engineers can make is to improve the performance of the main suppliers of electricity needs. It is impossible to separate the role of the system's components from the performance of the gas turbine generator. This journal discusses exergy and energy analysis in the gas turbine generator of X combined cycle power plant through simulation with Cycle-Tempo software. The simulation results show that the highest system energy efficiency is owned by the gas turbine generator unit 2.3 of 35.541%, with a system exergy efficiency of 34.069%. The lowest system energy efficiency is owned by the gas turbine generator unit 2.1 of 31.669%, with a system exergy efficiency of 30.355%. The gas turbine generator component with the lowest exergy efficiency occurs in the combustion chamber of the gas turbine generator unit 2.2 of 76.81%, with exergy destruction of 92.581 MW. Meanwhile, the gas turbine generator component with the highest exergy efficiency occurred in the turbine of the gas turbine generator unit 2.3 of 96.81%, with exergy destruction of 9.762 MW. The simulation results that have been carried out show that the performance of the components in the gas turbine generator is still in good performance, with the lowest exergy efficiency above 75%.

Hydrogenerator early fault detection: Sparse Dictionary Learning jointly with the Variational Autoencoder

Monitoring the continuous health status of a Hydraulic Turbine Generator Unit (HTGU) is a strategic task to prevent any unexpected downtime. In addition to the loss of energy production following a prolonged shutdown, the various maintenance costs represent an undesirable effect due to unanticipated failure. One of the main functions of a condition-based maintenance (CBM), is the early detection of any unexpected changes in a machine behavior. Indeed, being able to detect any drift or change in behavior compared to a reference behavior represents a major challenge in the monitoring of complex machines like a HTGU. In this paper, an early anomaly detection model for HTGU using Variational Autoencoders (VAEs) and Sparse Dictionary Learning (SDL) is proposed. The combined reconstruction error thus obtained from the VAE-SDL model is used as an early fault detection. Experimental tests on vibratory signals show that the two models thus joined increase the sensitivity as well as the robustness of the anomaly detection.

Increasing Efficiency and Capacity Expansion and Computer Monitoring Reformation of Aibu III Hydropower Station

The main problems and potential safety hazards of Aibu III Hydropower Station after extended service are analyzed. In view of the serious waste of hydraulic resources and low equipment efficiency of the power station, the expansion and reconstruction scheme of hydraulic turbine generator units is proposed, and the supporting design and implementation are carried out from all aspects of power station buildings, electrical engineering, calculation monitoring system, etc., which makes full use of hydraulic resources and completely solves the potential safety hazards of the power station, It has received good social and economic benefits. For the hydropower station after technical transformation, the operator on duty can monitor and control the operation status of main electromechanical equipment such as water turbine generator units, main transformers, transmission lines, high-voltage switches, station power, intake gates, unit main valves, and auxiliary equipment of the power station on the operator workstation in the central control room of the power station.

Data analysis and fault-finding case study of a 660 MW steam turbine generator set in a power station,

TG2 is a GE 660 MW steam turbine generator unit at Hartlepool power station in North East of England. The unit consists of an HP turbine, an IP turbine and three LP turbines coupled with an alternator and an exciter. Although the unit was previously operating normally and within the established ISO standards, recent reports indicated excessive loading on the barring gear and instances of the barring gear becoming stuck. EDF Energy's central technical organization conducted a comprehensive analysis of the vibration data, including online, barring, run up, and run down data, to determine the root cause of the overloading. The data analysis revealed that the generator NDE bearing (bearing 12) showed signs of tilting, reducing the clearance between the shaft and the bearing and causing friction. This friction was determined to be the cause of the overloading of the barring gear. The generator operates in a pressurized hydrogen environment and changes in pressure during operation and shutdown had a ratcheting effect on the bearing tilt and clearance reduction. The EDF Energy engineering team responded promptly and professionally, documenting the issue, raising awareness among operations, and implementing a recovery plan.

The Impact of Integration of the VSC-HVDC Connected Offshore Wind Farm on Torsional Vibrations of Steam Turbine Generators

For remote offshore wind farms, transmitting power to the main onshore grid via a Voltage Source Converter High Voltage Direct Current (VSC-HVDC) system is the mainstream of power transmission. It is not only cost-effective in long-distance transmission, but also can fully meet the grid side requirements such as black start, voltage support, fault ride through and frequency support. However, it still has some problems, such as the possible impact on the power grid needing to be paid attention to. In this paper, its impact on the torsional responses of turbine generator units neighboring to the onshore side of AC bus is studied by using the DIgSILENT PowerFactory software. It is found that the effects of the Sub-Synchronous Torsional Interaction (SSTI) with onshore controls and the generator de-rating operations can significantly affect the damping ratio of turbine torsional modes, whereas the effects of the machine configurations and the amount of wind farm power integrated can affect the electrical torque disturbance. The most noteworthy is that their effects can be superimposed on each other if these factors act simultaneously, which would lead to increased vibrations and reduce the turbine shaft’ s life. The findings will be helpful for avoiding accidents caused by torsional vibrations when it is going to integrate a VSC-HVDC connected wind farm into a power grid.

Research on the Torsional Vibration Response Characteristics of Parallel Operation Steam Turbine Generator Unit Shafting

With the continuous increase of unit capacity and the widespread application of series compensation devices in power transmission systems, the risk of coupling oscillation between units and power grids and between units has increased significantly, which seriously endangers the safe operation of units and power grids. In this paper, the torsional vibration response of each unit after grid failure is calculated by establishing a lumped mass model of the shafting torsional vibration of the parallel unit. The effects of fault type, series compensation degree and fault location on the torsional vibration of parallel unit shafting are studied. The results show that the three-phase short-circuit fault in the grid has a greater impact on the unit; the influence of series compensation degree on the torsional vibration of the shaft system decreases first and then increases; when the transmission line fails, it will produce a certain torsional vibration excitation effect on the shafting of all units; when a short-circuit fault occurs at the outlet of a generator, the torsional vibration excitation of the unit is the largest, but it will also produce a certain degree of torsional vibration excitation to other units in the same network.

An Application of the Pythagorean Fuzzy Sets in the Fault Diagnosis

Abstract In this paper, a comprehensive review and critical analyses of methods based on the ordinary fuzzy set, Atanassov’s intuitionistic fuzzy set, and its extensions have been conducted to show their limitations and defects. Then, a novel similarity measure based on the generalized score function has been introduced that incorporates the significance (importance) of information, making it more intuitive to compare them. The proposed method is employed for the fault diagnosis of steam turbine generator unit under Pythagorean fuzzy environment. Ten fault types of rotating machines are established as failure patterns in nine different vibration frequency ranges, expressed in terms of Pythagorean fuzzy numbers. The superiority of the proposed method in dealing with uncertain and vague information is shown by comparing it with some existing measures in numerical examples.

Diagnosis and Treatment of Burst Vibration Fault of Large Steam Turbine Generator Shaft System

Aiming at the burst vibration fault of a supercritical 600 MW steam turbine generator unit during the on-load operation, the characteristics of sudden vibration faults of the rotor system were compared and analyzed. By analyzing the weight-loss vibration response coefficient and the variation characteristics of the vibration vector, parts falling off fault at the low-low coupling of the rotor system were diagnosed. After inspection, it was confirmed that the burst vibration fault of the rotor system was caused by the falling-off of the blast baffle of the low-low coupling bolt. After the blast baffle was restored by hoisting the installation technique, the vibration of the steam turbine generator unit was stable during start-up and grid connection.

The study on high temperature exhaust orifice infrared suppression

A type of gas turbine generator unit has lots of advantages, such as small size, light weight, advanced technical performance, strong environment adaptability, rapid start. However, the high temperature exhaust gas generated during the operation of the machine leads to the high temperature and obvious infrared radiation characteristics near the exhaust port. The objective of this paper is to investigate the infrared suppression of the exhaust orifice of the gas turbine generator unit. Meanwhile, some schemes about infrared suppression are proposed, that is, redesigning the exhaust cover or adding grid regenerator of high temperature phase change materials(HTPCMs). The method of computer simulation experiment, relying on Gambit and Fluent for modeling, is used to demonstrate the feasibility of the scheme. Results indicate that the first enrichment of gas turbine exhaust heat can be completed and the exhaust temperature can be reduced by about 200°C when the grid is set as a three-layer pattern crisscrossed up and down.

Comparison of Impact on Turbine Shafts Torsional Behavior for Integration of Two Types of Wind Farm into a Series-Compensated Transmission System

Deep decarbonization is the goal of modern power systems, so it is inevitable that large-scale wind farms will be integrated into systems. This also gives rise to many problems, which have been studied in detail in the literature. However, these studies basically have two deficiencies. One is to assume that traditional generator units are fully loaded, and the other is not to compare the differences in the impact of different types of wind farm. This paper discusses these two points in detail. Taking a series-compensated transmission system as the research object, and assuming that the wind farm only replaces part of the power of the traditional generator unit in the transition period of energy conversion, the difference between the torsional vibration behaviors of the traditional unit caused by adopting different types of wind farm is discussed. The results of the study show that the impact of integration of the type 3 wind farm is dominated by the induction generator effect of doubly fed induction generator units. The penetration rate as low as 19% could cause instability. However, the paralleled metal-oxide varistor can effectively improve the stability. For the type 4 wind farm, the dominant factor turns out to be the de-rating operations of the steam turbine generator unit. The allowable penetration rate depends on the turbine damping. When the turbine damping is sufficient, the penetration rate can be as high as 87.5%. In conclusion, in order to integrate wind farms into a series compensated transmission system, one should not only focus on the compensation factor to avoid the sub-synchronous torsional vibrations, but also pay attention to the types of wind farm as well as the penetration rate. The findings can be used as the decision-making basis for the integration of wind farms during the energy transition period.

Water Losses in the Condenser Cooling System at the 905 MWe Power Unit

The paper focuses on water losses in the turbine condenser cooling system of the 905 MW power unit in Opole Power Plant (Opole Poland). The evaporative and drift losses are determined for various operating and atmospheric conditions. The drift loss is found to be 0.125–0.375% of the cooling water flux and some increase in this loss is noticed with increase in unit power and ambient temperature. The studies have shown that the presence of wind increases the total water loss related to the power generated by the power unit. This effect is analysed for selected constant air temperature values Tamb. The increase of the cooling water loss stream, related to the power of the unit, is at the level of 14.8% for Tamb equal to 7 °C, 23% for 15 °C, and approximately 10% at 22 °C. These increases are related to the level of losses in almost no wind conditions. It is investigated how the change in the cooling water flux affects the power unit operation and the amount of water loss. For the power unit under consideration, the reduction of the cooling water flux from 80,000 to 60,000 ton/h raises the temperature of water behind the condenser and lowers the temperature of the cooled water tw2 within the range of 0.75–1.5 °C, depending on the unit power and the ambient temperature. Reducing the cooling water flux in the analysed range results in an increase in condenser vapour pressure, within 0.5 kPa at Tamb = 25 °C. This increase is lower at lower ambient temperatures. Within the range of variations analysed, the effect of cooling water flux on evaporative losses is negligibly small. The increase in condenser steam pressure significantly affects the power generated by the turbine generator unit. The calculations show that it is possible to optimize the size of the cooling water flux for the analysed power unit and condenser cooling system. This optimization would allow (within a limited range of load variability) an increase in the net power generated by the power unit.