Turbo Generator Research Articles

Effect of Axial Clearance Between Turbine and Guide Wheel on Hydraulic Performance of Mine Borehole Turbo Generator

Abstract In order to study the influence law of axial clearance between turbine and guide wheel on the performance of mine turbine generator. The three-dimensional unsteady internal flow and external characteristics of 8 kinds of turbine generator models with different coaxial clearance are calculated. The results show that: As the axial clearance coefficient between the turbine and the guide wheel increases, the pressure loss at the inlet and outlet of the guide wheel and turbine increases gradually, the torque and shaft power of the turbine are reduced, the hydraulic efficiency of turbine generator decreases gradually; The hydraulic efficiency of the turbine increases first and then decreases. Considering the external and internal flow characteristics comprehensively, the axial clearance coefficient between the turbine and the guide wheel is between 0.12 and 0.15, and the turbine generator performance is the best. It can provide some reference for the design optimization of Mine Borehole Turbo Generator.

POWER ACCUMULATOR FOR STABILIZATION OF THE PRESSING PRESSURE OF THE CORE OF A POWERFUL TURBOGENERATOR WITH BUILT-IN METER

In this paper present described features of stabilization and restoration of pressing force of the stator core of a powerful turbogenerator (TG). Weakening of the pressing forces is the cause of a number of negative phenomena, such as increased vibration and loosening of the core sheets with their subsequent destruction (cracking), which is often the cause of generator damage. It is shown that to assess the state of the pressing force in the core of the TG stator, force meters in the clamping prisms of the core, built into the design of the power accumulator (PA) for stabilizing the pressing force of the core, can be used. The design of the package of disc springs used in PA consists of a package of plate springs and allows to stabilize the pressure in the stator core of a powerful TG to a given level without additional control with probes and fixation by tightening the adjustment nuts. Describes the advantages and features of using PA with a package of disc springs for pressure stabilization, installed under the tightening nuts or instead of them on the threaded ends of the tightening prisms. Proposed to use a built-in force measuring transducer, which consists of an elastic sensitive element (ESE) and a capacitive sensor (CS) into PA structure. The purpose of this article is to create a force meter in the clamping prisms of the stator core of a powerful TG using an elastic sensitive element and a capacitive sensor built into the design of a "caseless" power battery to stabilize the pressing pressure of the stator core of a powerful turbogenerator. A number of TG and PA parameters, which should know to calculate the mechanical characteristics of the disc spring unit outlined. The dependence of the force of the spring block on the displacement of the pressure plate of the stator core is determined. Showing that the assessment of the force in the tightening prism performed by measuring the electrical capacity between the potential electrode CS and the grounded element of PA. Measuring the height of the block during planned repairs or operation of the turbogenerator allows you to determine with high accuracy the amount of tension on each tightening prism and therefore the compression force of the core and, if it necessary to adjust the pressing force by tightening the springs. The conversion function of the force converter is determined, taking into account the geometric dimensions of the ESE and CS. The calculation of ESE for mechanical strength was carried out. The use of pressure gauges in tightening prisms allows you to effectively restore and maintain the pressing force of the final packages of the stator core, control the pressure during operation and adjust it without stopping the turbogenerator. The obtained results can be used in systems for stabilizing the pressing force of the stator core with power accumulators and in the system for assessing the current state of the stator core of powerful turbogenerators of the TGV-200 and TGV-300 type. Increasing the accuracy of measurements and reducing operational risks will contribute to the rapid and effective restoration of critical infrastructure and ensure the stable operation of energy facilities.

Structural health monitoring of turbo generator foundation

Structural health monitoring of turbo generator foundation

Measurement and calculation of harmonics in distribution power system with connected small co-generation facility Etan

Generation of electrical energy in large conventional plants (thermal, hydro, nuclear) in last ten years worldwide is being supplemented by small generation utilities. Etan is a gas refining facility. Power supply is provided by two turbo generators and each of them can independently cover the consumption of Etan. Etan usually works in insular operation, but it can also work parallel to the distribution system, especially in cases of maintenance of generator units. Etan is connected to the MV distribution power system (10 kV bus in substation 35/10 kV Ivanic Grad) through a 4,5 km long cable. Load in Etan consist mostly of induction motors. Power electronic devices are used for control of motor loads. The working process of the refinery is always the same so the load is not varying with time. It is very important to know the influence of this kind of industrial consumers with distributed generation on power quality. Power quality measurements were performed at three measurement points with the power quality analyzer ION 7650 of company Power Measurement. The aim of this paper is to compare harmonic measurements and calculations at all three measuring points in different operating conditions depending on the production of generator in Etan.

Patent Analysis of the Digital Synchronous Motor Excitation Regulator

A significant part of the devices at enterprises has been in operation since the eighties of the last century. A thyristor exciter is a system designed to control and stabilize the operating processes of engines that are part of devices operating at high speed. The efficiency of operation of such machines as compressors, fans, pumps directly depend on how high-quality exciters are installed in their design. Thyristor exciters are also designed for the generation of low-power hydro and turbo generators, synchronous motors and compensators. In order to increase reliability and ensure uninterrupted operation of a synchronous electric drive with optimal electrical performance, it is necessary to use high speed thyristor exciters, in our case, the digital excitation regulator of a synchronous motor — ANICRON. In comparison with electric machine exciters, thyristor ones require three times less maintenance costs. The improvement of the technical and economic indicators of a synchronous electric drive is carried out by reducing losses in power lines, increasing the reliability of the power electric drive, and additional capabilities of a thyristor-exciter device. To date, the effectiveness of such pathogens has been evaluated by enterprises in the sugar, chemical, energy and other industrial fields. Thyristors are widely used not only in the Russian Federation, but also abroad.

Detection of Shorted Turns in the Field Winding of Turbo Generators during Turning Gear Mode

Detection of Shorted Turns in the Field Winding of Turbo Generators during Turning Gear Mode

STABILIZATION OF THE REVERSING SPEED OF THE DRIVE MOTOR SYNCHRONOUS GENERATOR PRIVATE VOLTAGE WITH ACCUMULATORS BATTERIES

To limit the consequences of natural disasters and natural disasters (Japan's Fukushima NPP, Chornobyl NPP), reliable power supply systems are used for responsible mechanisms, which include engines of the cooling system of nuclear reactors, feed pumps and other consumers. Therefore, the use of reliable power supply systems increases the trouble-free operation of the station. Diesel generator sets, turbo generators, and batteries are used as sources of reliable power.
 A significant disadvantage of thermal sources of mechanical energy is the softness of external characteristics. Known sources do not cover the issue of using electromechanical converters for generating units with a capacity from 100 kW to several thousand kW.
 Theoretical studies on the basis of existing autonomous sources of power supply proved that existing heat engines do not allow to stabilize the speed of rotation of the synchronous generator, which feeds responsible consumers, even in the presence of a general-mode speed regulator. Therefore, a stabilization system was developed and proposed when powering a DC motor from a battery.
 The calculated dependences confirmed the stability of the generator rotation speed with the proper selection of the feedback coefficients.

Black Widow Optimization Algorithm-Based Sub Synchronous Resonance Investigation with Series Compensation

The integration of wind farms into the transmission network has raised various concerns and objections. To address these challenges, the deployment of series compensators has gained significance as an effective method for enhancing the power transmission capacity of existing lines, particularly for the integration of large-scale wind farms. However, the use of series reactive compensation lines can lead to a phenomenon known as sub-synchronous resonance (SSR) in turbo generators. This SSR can cause electrical instability at sub-synchronous frequencies and potential damage to the turbine’s generator shaft, particularly during periods of peak production. As a result, the assessment of SSR through comprehensive surveys is crucial for wind power engineers to make informed decisions and ensure the safety of turbines. This study explores the potential of SSR through the utilization of the black widow optimization technique. The analysis takes into account variables such as variations in the speed of the wind, compensation spectrum, and wind velocity and examines the eigenvalue and involvement components under various operating situations. To validate our findings, electromagnetic transient simulations are conducted using the PSCAD/EMTDC software, employing the initial IEEE reference systems. This research contributes to a deeper understanding of SSR and its implications for wind energy systems.

ВИМІРЮВАННЯ ЗУСИЛЬ В СТЯГУВАЛЬНИХ ПРИЗМАХ ОСЕРДЯ СТАТОРА ПО-ТУЖНОГО ТУРБОГЕНЕРАТОРА З ВИКОРИСТАННЯМ ДАНИХ ПРО ХІД БЛОКУ ТАРІЛЧАСТИХ ПРУЖИН В СИЛОВИХ АКУМУЛЯТОРАХ

The advantages and features of the use of pressure accumulators (CA) with blocks of conic springs for restoring and stabilizing the pressing pressure of the stator core of a powerful turbogenerator (TG), which are installed under the tightening nuts or instead of them on the threaded ends of the tightening prisms of the core, are described. It is shown that the measurement of the displacement of the compression disc spring in the CA makes it possible to estimate the current state of the pressing pressure. The use of a capacitive sensor of linear displacements, placed outside the CA, to control the movement of the spring block in the caseless CA is substantiated. According to the specified design parame-ters of the caseless CA and the value of the maximum stroke of the plate springs in it, a capacitive sensor with its speci-fied characteristics was developed. The method of monitoring the state of the TG stator core using the CA system with capacitive sensors on each CA and the control method with the alternate use of one disk spring travel meter are de-scribed. Ref. 14, fig. 6. Key words: powerful turbogenerator, stator core, pressure, forces in the tightening prisms, power accumulator, displacement of block compression disc spring, capacitive sensor.

Preliminary design of an OWC wave energy converter battery charger

This paper introduces a low-power off-grid oscillating water column wave energy converter with an internal battery bank. The research aims at the preliminary design and devising of the control strategy of a power electronics interface between the turbo generator and the battery bank. The converter comprises a spar buoy, a biradial turbine, a permanent magnet generator, a full-wave bridge rectifier, a braking chopper, a DC-to-DC step-down converter, and a lead-acid battery bank. The power-take-off system was modelled in Simulink/MATLAB, and its performance was assessed with steady-state simulations, considering a wave climate characteristic of Leixões, Portugal. The chamber pressure, the turbine, generator and rectifier performance were taken from experimental data sets. A simple battery model was derived from the manufacturer's datasheet. An ideal step-down DC-to-DC converter operating in discontinuous conduction mode regulates the battery charging current. This converter, in parallel with the braking chopper, adjusts the generator counter torque by regulating the current through the rectifier. Twelve system variables were recorded for selected pairs of input pressure and step-down converter design coefficient. The power at the rectifier's output terminals was mapped for the rotational speed and input pressure. The results show a system rating of 1.4 kW with 400 W of electrical power at 200 rad/s for the most frequent sea states. The range of the duty cycle, the inductance and the braking resistance were derived. Two closed-loop controllers were proposed for managing the step-down converter and the braking chopper. Their set points and saturation limits were derived from the simulation results.

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.

Влияние режима потребления реактивной мощности на техническое состояние турбогенератора Т3ФП-110-2МУ3

The necessity of turbogenerators operation in the reactive power consumption mode is determined by the shortage of compensating devices in the network. Recently, accidents associated with generators long-term operation at low levels of excitation have become more frequent, which is a prerequisite for the consumption of reactive power by the generator. The purpose of this research is to assess the effect of the reactive power consumption mode on the technical condition of the T3FP-110-2MU3 turbogenerator. The source of information about the technical condition of the turbogenerator is the data obtained from the operating and repair documentation, electrical and thermal tests protocols, technical reports with the results of comprehensive diagnostic examinations of the turbogenerator. The cores of T3F series generators have been examined. No gaps between the pressure fingers and the surface of the edge packages have ever been detected during examinations, which indicates the absence of significant curvature of the extreme core packages. During the study of temperature by T3FP-110-2MU3 thermal resistance converters, it is found out that with an increase of reactive power consumption, the temperature of the windings and the active steel of the stator core of the turbo generator decreases and it does not exceed the upper warning settings in the mode of reactive power output, the opposite dependence is visible. It is established that the influence of the reactive power consumption mode on the technical condition of the T3FP-110-2MU3 when operating in steady-state modes within the factory PQ-diagram is minimal. In the stator core of the turbogenerator under consideration, high resistance of the teeth of the extreme packages to operational loads has been achieved, due to significant improvements in the design and manufacturing technology of the end zones. From the point of view of practical significance, T3F series turbogenerators are allowed to be used for reactive power consumption. As a further direction of research, it is planned to consider the operation of turbogenerator in maneuverable modes with the transition from the issuance of reactive power to its consumption and vice versa.

Event-Triggered Communication in Cooperative, Adaptive Model Predictive Control of a Nuclear Power Plant’s Turbo–Generator Set

This paper discusses the issue of optimizing the communication between the components of a cooperating control system formed by a pair of MPC controllers of a nuclear power plant turbine set using online recursive least squares identification. It is proposed to use event-triggered communication, i.e., sending information only at selected time instants, as opposed to the standard approach where communication is triggered by time (time-triggered approach). The aim of this paper is to propose a change in the method of information exchange in the case of asynchronous communication between control system components and to prove its suitability for the selected application. Resignation from continuous communication in favor of sending information only at selected moments allows the load on the communication network to be reduced by approximately 90% while maintaining the quality of control.

Evaluation of an Energy Separation Device for the Efficiency Improvement of a Planar Solid Oxide Fuel Cell System with an External Reformer

Due to the high operating temperature of solid oxide fuel cells (SOFC), the system efficiency depends on efficient thermal integration and the effective construction of system configuration. In this study, nine configurations of system integration design were investigated to evaluate the possible improvement of system efficiency with energy separation devices. The models were developed under the Matlab/Simulink® platform with Thermolib® module. The reference layout of the simulation included an SOFC stack, a compressor, an external reformer with a burner, a three-way valve, a heat exchanger, and a water pump. From the reference case, eight cases extended layouts for the capability of thermal energy utilization with a catalytic converter, SOFC hybridization, and an energy separation device. Since the energy separation device was beneficial to thermal energy utilization via a boost to the gas temperature, electric efficiency, and combined heat and power (CHP) efficiency was improved with the thermal integration of the energy separation device with a turbo generator.

NOISE MAPPING IN THE TURBINE AREA AT PT POMI

Background: One of the problems faced by industrial companies that use large machines and work equipment is noise. Steam power plant companies will certainly face noise problems in their work areas. PT. Paiton Operation and Maintenance Indonesia is one of the private power generation companies in East Java which manages three units of PLTU (Steam-Electric Power Plant) which in the process operates using a turbo generator. In addition, this company uses machines and equipment that produce noise that can potentially interfere with the health of the workers. Purpose: To map the noise with Golden Surfer software and to analyze the control efforts that had been carried out. Method: This research used an observational method and the analysis was done using Golden Surfer software. Result: The results of this study indicated that in general the noise that occurred in the turbine area exceeded the threshold value which was >85 dB. Furthermore, the results of the mapping showed the distribution pattern of noise levels that occurred in the turbine area starting from the first floor to the fifth floor. Noise control efforts were also carried out by the company, including noise measurements, scheduled preventive maintenance for machine repairs, safety sign, audiometric checks, work procedures, and PPE. Conclusion: In addition to this noise mapping, noise control efforts that have been carried out by the company will reduce the risk of health problems for workers. Thus, noise mapping can be used as a basic reference for companies to be able to determine additional noise control as an effort to prevent and control noise.

Forecasting the eddy current loss of a large turbo generator using hybrid ensemble Gaussian process regression

For the issue that the sample space of wedge winding eddy current losses of large generator does not obey Gaussian distribution, a hybrid ensemble Gaussian process regression (HEGPR) model is proposed in this paper. The HEGPR contains three layers. First, four tree regression models (XGBoost, CatBoost, LGBM and NGBoost) are built. Then, the output of the first layer is taken as the input of multiple Gaussian regression models, so that the input samples of the second layer obey Gaussian distribution, which can effectively improve the generalization ability of Gaussian process regression. The results show that the root mean squared error (RMSE) is 0.0282 and the goodness of fit (R2) is 0.9973. The model has good prediction performance for the eddy current loss of large turbo generator. Compared with kinds of Gaussian process models and traditional ensemble learning models, the prediction accuracy of this model is higher, and it is more suitable for forecasting eddy current loss of the large generator. HEGPR model can effectively solve the problem of insufficient regression accuracy of Gaussian process when sample space does not obey Gaussian distribution.

Early warning of stator winding overheating fault of water-cooled turbogenerator based on SAE-LSTM and sliding window method

Aiming at the early warning of overheating defects in the stator winding of water-cooled turbogenerators, this paper proposes a novel method based on SAE-LSTM and sliding window method by combining the Sparse Auto-Encoder (SAE) and the Long–Short Term Memory network (LSTM) with highly time dependent time series data characteristics. Firstly, the sparse auto-encoder is used to reconstruct the operation data collected by the Distributed Control System (DCS) installed on the turbogenerator to extract the data characteristics; Secondly, the LSTM prediction model optimized by attention mechanism is used to predict the outlet temperature of each slot of the stator winding of the turbogenerator under normal working condition; Then, the sliding window method is adopted to detect the stator winding overheating defect, and the alarm threshold is defined based on both the maximum mean value and maximum standard deviation of the predicted residual within the window. Finally, the proposed method is validated by using the historical DCS data of a turbo generator with stator winding overheating defect before failure,and the results show that compared with the traditional threshold warning method, the proposed method can warn the defects 85 h in advance, which provides strong support for the stable operation of the turbogenerator.

Implementation of optimal oil flushing methodology for nuclear steam turbo generator oil circuits

The first turning gear operation is regarded as a significant milestone in the overall activities of Turbine Generator system commissioning. To accomplish this critical goal, the lube oil circuit must be clean and free of all type of contaminants. The purpose of this paper is to elaborate on the various flushing tactics used in the Prototype Fast Breeder Reactor 500 MW Turbo Generator (TG) oil systems, to understand the factors that influence oil circuit flushing, the difficulties encountered during flushing, and to optimise the flushing process of TG oil circuits. Also A simple method was used in this paper to determine the minimum amount of oil required to begin flushing and the make-up requirements of lube oil at various stages of flushing. The percentage of oil passing through the cooler and cooler bypass line during the thermal shocking process was also determined using an energy balance approach. Based on TG oil circuit commissioning experience, an optimised methodology for completing the TG oil circuits flushing exercise is also proposed. This study demonstrates that the cooling and heating times of lube oil can be controlled during oil flushing, resulting in an increase in the number of thermal shocks per day and a significant reduction in flushing time.Article HighlightsThis paper is the result of flushing experiences with oil circuits of a 500 MW Nuclear power plant. This can be used to minimize oil quantity and the time flushing thereby lot of man hours and cost of flushing could be saved during flushing of turbine oil circuits.The minimum oil required for turbine oil circuit flushing is not readily available. The method outlined here can be used to determine the minimum amount of oil required for each stage of oil circuit flushing.This paper describes an energy balance methodology that can be used to increase the number of thermal shocks per day during flushing, thereby significantly reducing flushing time.

Onshore and offshore turbo generators preventive maintenance program

The aim of this article is to suggest a common preventive maintenance program for large turbogenerators used on onshore or offshore, the objective is to be generic, under the intention to allow owners of different turbo generators brands a level of standardization. It motivation derives from lack of literature under this approach, either publication from the own manufacturers or old literature were found, in the time where industry 4.0 productivity and availability needs to work together, and the suggest preventive maintenance program works to collaborate on this direction

Onshore and offshore turbo generators preventive maintenance program

Onshore and offshore turbo generators preventive maintenance program