MW Generator Research Articles

A method for measuring carbon emissions from power plants using a CNN-LSTM-Attention model with Bayesian optimization

Accurate measurement of CO2 emissions from coal-fired power plants is crucial for achieving China's “carbon neutrality” goal; however, traditional CO2 emission measurement methods have several limitations, and emerging prediction models rarely utilize real-time monitoring data from power plants at the micro level. To address these challenges, this study presents a novel hybrid convolutional neural network with long short-term memory (CNN-LSTM)-Attention model, leveraging real-time monitoring data to enhance the accuracy of CO2 emission predictions. The proposed model employs a hybrid architecture that leverages the strength of CNN, LSTM, and Attention mechanism. To address the challenges of multiple hyperparameters and difficult selection, the Bayesian optimization algorithm is used to optimize the hyperparameters ensuring optimal performance. Using historical operational data from a 660 MW generator set in Hubei province, the proposed model was evaluated and validated horizontally by using three evaluation metrics. Additionally, the vertical evaluation and validation of the proposed model were done using the operational data from other months. The results indicate that the proposed model achieved the highest performance across every evaluation index for predicting CO2 emissions from coalfired power plants, and the prediction accuracy of the CO2 emission in the future months is also guaranteed.

AC loss analysis on an HTS field winding of the generator with T-A formulation

In this study, we proposed a coupling model utilizing finite element software to estimate AC loss on the high-temperature superconducting (HTS) field winding of a 1 MW generator. The model comprises three distinct physical modules: rotating machinery and magnetic (RMM), electrical circuit (CE) and partial differential equation (PDE). These modules collaborate to resolve the generator's magnetic field distribution, rated output parameters and degree of current magnetization on the HTS field winding, employing Maxwell equations and T-A formulation. Given the placement of the HTS field winding on the rotor core, accurately calculating its loss in an electromagnetic field that varies both temporally and spatially presents a considerable challenge. To address this issue, we adjust the coordinate system within the PDE module to vary with the material rather than space. Our analysis reveals that the instantaneous AC loss of an HTS field winding comprises two primary components: the attenuation envelope and the oscillatory variation, resulting from the charging process and external harmonic magnetic fields. Additionally, we comprehensively discuss and analyze the influence of current excitation speed on instantaneous AC loss. Accurately estimating AC loss in HTS field windings is a critical and meaningful aspect of preliminary machine design. This study provides an essential reference for addressing this issue.

Computational boundary improvement and performance optimization of the flue gas waste heat cascade utilization system of the ultra-supercritical 1000 MW generator set

Abstract There is no uniform performance test rule and standard calculation method for efficiency improvement of a system that utilizes waste heat from flue gas and it is mainly carried out through turbine parameters, without considering boiler system performance. Given the above problem, in this paper, the steam turbine, boiler and waste heat from the flue gas step-up utilization system are calculated by establishing a thermal model of ultra-supercritical secondary reheating 1000 MW unit. At the same time, unit design data and field performance test results are used for verification. Analysis comparing simulation outcomes with experimental data revealed that the discrepancies in the heat consumption rate per unit, the efficiency of the boiler, and the rate of coal consumption for power generation peaked at a marginal variance of 0.2%. The optimum operating parameters of the system for low-grade flue gas recovery in a cascading manner are obtained through variable operating condition calculations. The optimum value of high-pressure bypass feed-water flow rate is 52 kg/s at 970 MW operating condition. At the same time, the difference between high-pressure bypass effluent and high plus effluent temperatures should be controlled to be close to 0°C, and the optimal value of low-pressure bypass condensate flow rate is 53 kg/s. As the flow of flue gas in the bypass increases, the efficiency of heat exchange in the bypass economizer also increases, resulting in greater absorption of heat in the utilization apparatus for flue gas waste heat, leading to a more effective energy-saving outcome. However, it is necessary to regulate the temperature of both the primary and secondary air to levels that exceed the minimum requirements for the safe functioning of the coal mill.

ANALISA SETTING PROTEKSI OVER CURRENT RELAY (OCR) PADA GENERATOR 30 MW UNIT PLTA POSO PT. POSO ENERGY

To ensure that the performance of the protection system is still good or not in terms of protection, calculations and adjustments must be made to the safety relay settings, especially the over current relay. In the research, analysis of the over current relay protection settings on the 30 MW generator at the Poso 1 PT PLTA unit. Poso Energy obtained that the maximum load current data on the generator was 2042 A, while the calculation results obtained were 2041.7 A. For the relay (top) operating time in the specification data, the value was 1.4 s, while in the calculation results it was 1.3 s. And for the setting current (Is) in the specification data the value is 4.7 A, whereas in the calculation results it is 4.28 A. Over current relay (OCR) or over current relay is an auxiliary relay from the differential relay, the over current relay is used to secure the generator of the overcurrent in the Poso 1 PLTA is PCS-985GE-EN-H2-110V-5A. In the specification data, the TMS value is 0.15 s, while in the calculation results it is 0.14 s. This means that data in the field is slower to protect components from interference by 0.01 s. However, overall the overcurrent relay settings on the generator at the Poso 1 PLTA are still in good condition.

Numerical Investigation of a Floating-Type Support Structure (Tri-Star Floater) for 9.5 MW Wind Turbine Generators

A numerical investigation of floating-type substructures for wind turbine generators was conducted by using time-domain simulation. A Tri-Star floater for 8–10 MW generators, which was developed by Samsung Heavy Industries (SHI), was chosen as the floating substructure. To make the anchor system, catenary mooring lines, considering redundancy, were installed on the floater. The main sources of external force on the wind turbine generator are wind, waves, and currents. To consider severe environmental conditions, Design Load Cases (DLCs) 1.6 and 6.1 of the IEC guidelines (IEC 61400-3-1) were chosen. From the measured environmental data for the installation site, the main parameters for the simulation conditions were obtained. The tilt angle and horizontal movement of the floater and the mooring tension for the different mooring systems were checked. The response of the floater during the failure of the mooring was also studied, and the critical failure of the mooring was confirmed. During the failure of the mooring, the redundancy system worked well, in which the movement of the floater was constrained within the criteria for all scenarios.

Design and Simulation study of 40 MW PM Generator for the CRAFT

Design studies of two counter rotating permanent magnet (PM) synchronous generators have been performed. The two 40 MW generators have been designed and compared for the Counter Rotating Axis Floating Turbine (CRAFT) with different air-gap diameters. The generators are modelled with validated full physics finite element method (FEM) which also includes dynamic simulations. The simulations are performed by using an electromagnetic model. The model is described by combined field and circuit equations and is solved in a finite element environment. The stator winding of the generators consists of circular cables and the rotor consists of buried ferrite PM. The generator with smaller air-gap diameter will have lower material costs due to smaller frame but higher due to use of more active materials. A comparison of the counter rotating generators with a traditional direct drive has also been performed by maintaining the same voltage but reducing the rotational speed by half. This shows that a generator with a higher rotational speed will have lower material costs due to smaller dimensions and lower weight. Furthermore, a design variation, to reduce the cogging and harmonic content of the voltage by changing the pole shoe, was analyzed. In conclusions, a 40 MW generator design for the CRAFT has successfully been simulated with a multi-physics-FEM. The advantages of using a counter-rotating generator has been established.

Application of an Improved Ridgelet Process Neural Network for Predicting the Temperature Rise of Rotor Structure Optimization

To solve the negative-sequence temperature-rise problem of large equipment under asymmetric operating conditions, this paper optimizes the structure of the main components and adopts an improved process neural network to conduct online analysis and calculate the operating data, achieving the accurate prediction of the equipment heating status. Firstly, taking a 300 MW generator that urgently needs equipment improvement as the research object, the typical asymmetric accident characteristics that have occurred in recent years and the main influencing factors of negative-sequence heating of the rotor are analyzed. The influence of the rotor damping structure and shaft length on the temperature-rise change is explored. Secondly, a tent map is introduced to enhance the distribution uniformity of the population in the search space to enhance the global convergence of niche genetic algorithms. Numerical experiments and field experiments show that the improved algorithm, which is applied to optimize the parameters of the ridgelet process neural network, has good temperature-rise prediction performance. Finally, the influence of the rotor length and number of pole damping bars on the negative-sequence heating problem under different negative-sequence component ratios is examined, which provides useful references for the structural optimization and asymmetric operation state prediction of large equipment.

Failure investigation of brazed copper winding bar strands of 250 MW stator

The present failure analysis investigates the failure of copper connectors and bus-bar windings of a 250 MW generator unit, of a steam powered turbine, which failed during service. An exhaustive microstructural and nanomechanical characterization was conducted in-order to determine the failure of copper bus-bar. Microstructure analysis revealed porosities in the brazed region with formation of numerous microconstituent phases. Furthermore, microstructure analysis revealed a network of numerous intergranular porosities on the failed copper side. SEM-EDS analysis of different microconstituents revealed a presence of Ag-rich dendritic phase, Cu-rich phase and lamellar eutectic microconstituents, highlighting a diverse microstructure. Nanoindentation measurements of different microconstituents and phases revealed a stark difference in the indentation hardness, thereby highlighting a strong mismatch between the observed microconstituents and phases.

Application of genetic algorithm and terminal sliding surface to improve the effectiveness of the proportional–integral controller for the direct power control of the induction generator power system

The proportional–integral regulator is one of the most famous and widely used linear controllers in the industrial field because of its easy adjustment of the results, simplicity, and inexpensive. The negative of this controller is that it is affected by the change of system parameters, which causes several problems, including the high value of ripples and low quality of the power/current. To reduce this defect, a new proportional–integral regulator is suggested based on the use of the terminal sliding surface technique and genetic algorithm. This suggested nonlinear controller is discussed for the first time in this work to use it to ameliorate the quality of energy output from a dual-rotor wind power system using an induction generator. The use of a new controller to regulate the generator energy will inevitably lead to an increase in power errors, power ripples, and harmonic distortion of current especially if the system parameters are changed. Also, the traditional direct power control based on the proposed nonlinear controllers of the induction generator is a robust control, does not need the mathematical form of the generator, is simple, and does not need a specialist. Moreover, the suggested method is applied to the rotor inverter of the 1.5 MW generator using Matlab software. The suggested technique takes full advantage and the power regulation objective of the suggested power system is confirmed by the numerical results compared to the conventional technique and other published controls.

Analisis Kestabilan Transien Akibat Penambahan Generator di Pabrik Gula

The Assembagoes sugar factory has a production capacity of 3000 TCD and was revitalized in 2015, increasing the capacity to 6000 TCD. With the increase in production capacity, the supply of electrical energy, which had previously only come from one generator unit, was supplemented with one new 13 MW generator unit, increasing the total generation capacity to 23 MW. With this addition, the operation pattern of the electrical system changes, and the problem of system stability becomes one of the primary concerns that must be analyzed with improvements to the Assembaggoes sugar factory's electrical system. The goal of this research is to determine the system's frequency and voltage response when a brief stability disturbance occurs.

Analisis Pengaruh Penambahan Suplai Daya 1000 MW Terhadap Performansi Jaringan Backbone 500 kV

Based on the Decree of the Minister of Energy and Mineral Resources (ESDM) Number 0074.K / 21 / MEM / 2015 concerning the Ratification of the 2016-2025 Electricity Supply Business Plan (RUPTL), the load growth every year has increased. Therefore, there will be additional Generating Units with a capacity of 1000 MW at PLTU Paiton, it is necessary to analyze the effect of additional loads in 2017 - 2022 on the 500 KV GITET system before and after the addition of a 1000 MW generator. Based on the analysis, it is known that the additional power of 1000 MW will strengthen the Paiton GITET reserve margin in bearing the load growth, it can be seen from the reserve margin value before the addition of power plants by 16% and after the addition of 29%. For the ability of the Paiton - Grati GITET transmission line until 2022, the load is 62% with a power loss of 35.41 MW (2.85%) and the load on the Paiton - Kediri GITET transmission line is 62% with a power loss of 35.41 MW (2.85%) indicates that the channel still in good shape. In addition, the load condition for the IBT transformer until 2022 is 84%, it can be concluded that the transformer is in good condition

The techno-economic-environmental analysis of a pilot-scale positive pressure biomass gasification coupled with coal-fired power generation system

Biomass gasification coupled with coal-fired power generation (BGCPG) is of great significance for alleviating energy shortages and environmental pollution. Here we propose, analyze and validate a BGCPG system under positive pressure for cleaner applications based on a pilot-scale fluidized bed gasification plant and discussed the possibility of higher economic output and operating stability with reduced pollution emissions. Then the effects of temperature, air equivalence ratio and operating pressure were experimentally investigated for parameter optimization. The processes under positive and negative pressure were simulated and compared based on the pilot-scale experimental data, and the effects of the mixing ratio and operating pressure were investigated. Furthermore, the economic and sensitivity analyses were conducted for both a traditional coal-fired power plant and simulated BGCPG systems. The results demonstrated that the gas calorific value, gas yield, and gasification efficiency increased with the gasification temperature increasing, whereas the opposite trend was observed for the gas calorific value with the air equivalence ratio increasing. The positive pressure operation had little influence on the gasification process. The flue gas flow rate increased, and the furnace temperature decreased with an increase in the mixing ratio of biomass and coal. The reduction in fuel NOx and SOx was caused by the decreasing coal content, whereas the decrease in thermal NOx and boiler thermal efficiency was due to the increasing exhaust temperature. Compared with functioning under negative pressure, operation under positive pressure at a 20% mixing ratio could effectively reduce the pollutant emissions of SOx, NOx and dust by 5.64%, 8.8% and 20%, respectively. The generation costs of the BGCPG system under negative and positive pressure conditions were 0.05593 $/kW·h and 0.05582 $/kW·h respectively, indicating that a positive operating pressure would increase the economic benefit of a 660 MW generator by 5.808 × 105 $/year. These findings suggest the effectiveness of clean power generation with a higher economy and lower pollution emissions.

Focus Fusion: Overview of Progress Towards p-B11 Fusion with the Dense Plasma Focus

LPPFusion is developing a source of fusion energy using the dense plasma focus device and p-B11 fuel, a combination we call Focus Fusion. So far, this project has led to the achievement of the highest confined ion energies of any fusion experiment (> 200 keV) as well as, recently, the lowest impurities of any fusion plasma. Among privately-funded fusion efforts, our experiments have achieved the highest ratio of fusion energy generation to device energy input (wall-plug efficiency) and the highest nτT product of 3.4 × 1020 keV-s/m3. Our calculations and simulations indicate that the quantum magnetic field effect will allow a great reduction in bremsstrahlung radiation with p-B11 fuel. For commercial fusion, this approach has several major advantages. The small size and simplicity of design of the DPF can lead to 5 MW generators that are much cheaper than any existing energy source, that can be manufactured by mass production and that can be located close to loads. It shares with other p-B11 approaches a lack of neutron damage and radioactive waste. Direct energy conversion of the ion beam and x-rays produced by the device avoids the high costs associated with thermal cycles. With adequate, but still modest, financial resources we anticipate working prototype generators could be ready for production by 2026–2030.

Application of Improved Process Neural Network Based on the Fireworks Algorithm in the Temperature-Rise Predictions of a Large Generator Rotor

Building an effective algorithm model for large key power equipment has very important research significance and application value. Aiming at the typical operating state characteristics of large generators and taking the temperature changes as the main research indicators, the improved fireworks algorithm was used to optimize the process neural network, and the key data characteristics were studied based on the machine experiment and actual operation data of a 300 MW generator so as to find the variation and development trends of the maximum temperature rise caused by negative-sequence current. Furthermore, the effectiveness of the neural network model suitable for large generators established in this paper was verified by test functions and experiments. On this basis, the calculation method was applied to different working conditions, component materials, and heating positions of the generator. Moreover, the temperature-rise prediction results of the structural components for the generator rotor were obtained, and the optimization scheme of the slot wedge material given, which provide a reference for temperature-rise research and the selection of component materials for large generators.

Design and Analysis of 15 MW SPM Vernier Generator for Direct-Drive Wind Turbine Applications

This paper presents the design and an analysis of a surface PM vernier generator (SPMVG) for MW-scale direct-drive (DD) wind turbine application. An SPMVG has the advantage of higher torque density; however, especially at higher power ratings with increased electrical loadings, the power factor worsens and there are some serious concerns including magnetic saturation of cores and PM demagnetization. These issues are directly related to machine design parameters such as PM dimensions, applied electrical loading, slot geometry and the choice of slot–pole combination. It is determined that depending on the PM thickness and a few other design variables, each slot–pole combination has an optimal value of specific electrical loading. The use of the optimal value of specific electrical loading ensures that the machine is not saturated, the performance is optimum and the power factor is not unnecessarily degraded. Moreover, under certain design constraints, design criteria are developed that ensure the proper choice of various entailed design variables. By using the developed design criteria, the trends of various electromagnetic performances with variation in the slot–pole combination are discussed. The obtained trends clearly show that each slot–pole combination offers a certain torque density and power factor; thus, it serves as a guide for the selection of the slot–pole combination considering the required torque density and/or certain power factor limit. Finally, by using the developed design approach, an SPMVG for rated power of 15 MW is designed; the design objectives are to maximize torque per volume with a power factor limit of 0.4. Moreover, the various aspects of the performances of the designed SPMVG are comprehensively compared against a conventional PM DD 15 MW generator.

Increasing Capacity Impact of Power Source Sinergy on Power Flow Evaluation Based on Auxiliary Generator

Steam power plant PT Sinergy Power Source is one of the private steam power plants that have a capacity of 30 MW and supplies 3 main expenses namely PT Mekabox, PT Sopanusa, and PT Sunpaper. Currently, the total load that must be fulfilled by steam power plant PT SPS for the three factories is 25.33 MW and will continue to grow because of the increase in the production number of each plant. With the increasing amount of production, the amount of load will increase so that additional generator capacity is required. This research aims to determine the analysis of power flow planning and coordination setting system protection against the addition of 30 MW generator capacity. Analyze the power flow using ETAP software with the Adaptive Newton-Rapson method. The results of the study showed after the 30 MW generator was added, the work percentage of generators 1 and 2 was lighter and the value of the power flow is relatively the same if the load value is unchanged. For coordination of protection systems itself has been running correctly to handle disruption.

АНАЛИЗ СИСТЕМ ВОЗБУЖДЕНИЯ СИНХРОННЫХ ГЕНЕРАТОРОВ ЗАВОДСКИХ ЭЛЕКТРОСТАНЦИЙ

One of the priorities in the development of metallurgical enterprises is to increase own generation of electricity. At the largest enterprises in the sector – PJSC MMK (Magnitogorsk), Severstal PJSC (Cherepovets), PJSC “NLMK” (Lipetsk) Electricity generation is 60–70% of total consumption. This contributes to two factors: firstly, the presence of secondary fuel gases – coke and domain; and secondly, unreasonably high electricity tariffs. Thus there is an urgent need to ensure sustainable trouble-free operation of factory generators and basic systems. Automatic excitation control systems (ARV) are the most important factor when determining the state of the generator in various modes. The main requirements for ARV systems determine the specific working conditions. We will highlight the most significant and significant of these. 1. Low power 10–50 MW generators are connected to an external power system on 110 kV buses, where the short circuit capacity is within 3000–5000 mba. Thus the possibilities of regulating and maintaining voltage are very limited. 2. Since the electricity produced by its own power plants is 2–2.5 times cheaper than purchased power, almost all generators work with a power factor close to one. This significantly reduces their stability in the power supply system. 3. The voltage at the point of connection and loading of the Eigen needs for the generator voltage stations are unsta-ble. Therefore, in order to preserve the stability of generators in transient modes, the most preferred is the ARV system with a switching structure in which the settings and regulation laws are selected depending on Work modes. The work gives a general review of the existing laws and the proposed arousal regulation law, adapted to the condi-tions of factory generators of small and medium-sized power, working concomitantly with a high power grid.

Assessment of Operational Performance for an Integrated ‘Power to Synthetic Natural Gas’ System

This article presents a power to SNG (synthetic natural gas) system that converts hydrogen into SNG via a methanation process. In our analysis, detailed models for all the elements of the system are built. We assume a direct connection between a wind farm and a hydrogen generator. For the purposes of our calculations, we also assume that the hydrogen generator is powered by the renewable source over a nine-hour period per day (between 21:00 and 06:00), and this corresponds to the off-peak period in energy demand. In addition, a hydrogen tank was introduced to maximize the operating time of the methanation reactor. The cooperation between the main components of the system were simulated using Matlab software. The primary aim of this paper is to assess the influence of various parameters on the operation of the proposed system, and to optimize its yearly operation via a consideration of the most important constraints. The analyses also examine different nominal power values of renewables from 8 to 12 MW and hydrogen generators from 3 to 6 MW. Implementing the proposed configuration, taking into account the direct connection of the hydrogen generator and the methanation reactor, showed that it had a positive effect on the dynamics and the operating times of the individual subsystems within the tested configuration.

Analysis of bidirectional 15 MW current source DC/DC converter for series-connected superconducting-based 1 GW/100 kV offshore wind farm

A wind farm with series dc collection can potentially eliminate the costly offshore platform and its step-up components. Multiple series strings can be connected in parallel to extend the power capacity for a given voltage. In such arrangement, the DC/DC converters for individual generators are rated at only a fraction of the transmission voltage. The maturity of superconducting cable technology will eliminate the difficulty of transmission losses with high current low voltage systems. This paper presents a feasibility study on the DC/DC converter design for a parallel-series-connected wind farm. The isolated front-to-front (F2F) mixed voltage source converter (VSC) and current source converter (CSC) is examined with power back-feeding capability during wind calm periods for a 15 MW generator. A novel configuration using 3-level (3L) VSC and thyristor-based CSC with combinational control of AC voltage magnitude, frequency, and thyristor delay angle is proposed and evaluated for a 1 GW/100 kV parallel/series wind farm based on the superconducting cable. Detailed converter model including power loss estimation in PSCAD is presented to support the converter design recommendations.

Analysis and Treatment of a Large Abnormal Vibration of 10 Watts in a 1000 MW Generator due to the Deformation of the Rotor End Winding

With the widespread application of large-capacity and high-parameter generators in the field of coal-fired power generation, there are more and more cases in which the vibration at both ends of the generator increases abnormally with load changes. This article introduces in detail the analysis and treatment process of the abnormal continuous increase of the 10-watt vibration of a 1000MW turbo-generator after it has been put into operation for two years. After the rotor returned to the factory for disassembly and overhaul, it was finally confirmed that the stacking of the full-size insulating tiles under the guard ring caused partial blockage of the winding deformation of the rotor end and the ventilation holes were the direct causes of abnormal vibration of the generator.