냉각층이 고려된 대용량 동기 발전기의 전자기 특성 해석 및 열전달 해석

권도윤,김창우,최장영,임민수 한국자기학회 2019 韓國磁氣學會誌 Vol.29 No.4

This paper deals with the heat transfer analysis through the electromagnetic- thermal coupling analysis of large scale synchronous generator. The synchronous generator is a wound field synchronous generator, and the operation characteristic curve is derived through electromagnetic analysis. Through this, the synchronous generator is classified into the heating limitation region by the armature winding, the field winding, and the stator end region. Next, for the analysis of the main heat source of generator, the losses incurred at the rated output within the heat limit region were calculated. Core loss was derived by using finite element method and copper loss was calculated by using the copper loss equation. Finally, the characteristics of the generator based on the air-cooled system were analyzed by the convection heat coefficients through the electromagnetic-thermal coupling analysis. Convection heat coefficients were considered both natural convection and forced convection, and confirmed the thermal analysis according to the convection coefficient, generator saturation temperature, and thermal strain alalysis.

Electromagnetic Torque Characteristics Analysis of Nuclear Half-Speed Turbine Generator with Stator Winding Inter-Turn Short Circuit Fault

Xin Peng,Ge Baojun,Tao Dajun,Lv Pin 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4

To research the variation characteristics and infl uence factors of air gap magnetic fi eld and electromagnetic torque of nuclear power half-speed turbine generator with stator winding inter-turn short circuit, the two-dimensional transient electromagnetic fi eld of generator-external circuit-grid coupling mathematical model is established by fi eld-circuit-network coupling method. Taking the national laboratory’s generator as an example, and comparing the simulation results of the inter-turn short circuit of the armature winding with experimental data, the correctness of the model is validated. On this basis, the simulation model of a 1407MVA nuclear power half-speed turbine generator is built. Then the stator winding inter-turn short circuit fault is simulated when the generator is connected to the grid with rated load. The characteristics of air gap fl ux density and electromagnetic torque are obtained before and after fault, as well as, the relationship between their each component and the fault degree is obtained. At the same time, the variation law of air gap fl ux density and electromagnetic torque is obtained when the relative position between fault winding and magnetic pole changes. The theoretical reference for fault diagnosis and localization using harmonic electromagnetic torque after fault is provided

Quantitative Analysis of Electromagnetic Torque Generation Mechanism in Axial-Flux Permanent Magnet Machine Based on the Air-Gap Field Modulation Theory

Li Jie,Yang Gongde,Liu Jinliang 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1

This paper proposes two axial-fux permanent magnet (AFPM) machines, i.e., NS and NN type, which all have the same stator and rotor structures but the diferent magnetic circuits. Since both PM magnetomotive force (MMF) and armature reaction MMF of the proposed AFPM machines are modulated by H-type armature stator, more feld harmonics that contribute to electromagnetic torque will be generated. The electromagnetic torque generation mechanism of the proposed AFPM machines is revealed and investigated from the perspective of air-gap feld modulation. The MMF-permeance model is established to analyze the feld modulation process of the PM MMF and armature reaction MMF. Based on the efective air-gap feld harmonics that generating steady electromagnetic torque, the electromagnetic torque generation mechanism of the proposed AFPM machines can be confrmed. A fnite element-based harmonic restoration method is used to quantify the electromagnetic torque generation mechanisms of the proposed AFPM machines. It shows that the total electromagnetic torque of the AFPM (NN) machine is lower than that of the AFPM (NS) machine, while the AFPM (NN) machine has higher feld modulation electromagnetic torque component due to the more signifcant feld modulation efect.

자기력을 고려한 대형발전기의 진동해석

이재욱(Jae-Wook, Lee),배재남(Jae-Nam, Bae),정계환(Kye-Hwan Jeong),김근웅(Keun-Woong, Kim) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11

Vibrations on industrial generators can be divided into electromagnetic, mechanical and aerodynamic vibration. Among them, the electromagnetic vibration is produced by combination of natural frequency and harmonics of magnetic flux, so it is relatively hard to predict the electromagnetic vibration. In this paper, we developed 1-way coupled (magnetic, stiffness) analysis technology to evaluate characteristics of the vibration induced by electromagnetic field. With the analysis, we investigated the forced vibration characteristics considering radial magnetic force, which was calculated from the magnetic analysis, on stator core teeth of the generator. And structure design reducing the electromagnetic vibration of the generator was suggested from the analysis results.

Electromagnetic Field Analysis of the Dovetail Key Bar Voltage in a Generator

Dae-Il Song,Ju Lee 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.8

For increased product competitiveness, the development of generators of the same size, but with more outputs, is in the spotlight. This development trend has resulted in the magnetic flux density inside the generator being increased. The magnetic flux of the generator flows through the stator core, which is supported by the key bar. Increased magnetic flux density leads to a higher voltage in the key bar, which reduces the reliability of the generator. In this paper, we report on an electromagnetic field analysis of the key bar voltage and the verification of the result by the using the factory test. We also suggest a point to consider when designing a key bar.

3D Electromagnetic-Temperature Field Close-Coupling Calculation of Losses and Heat in the Damper Winding of a Large Tubular Hydro-Generator

Kun Wen,Li Han,Zhi-ting Zhou,Zhen-nan Fan,Yong Liao,Jun Wang,Zhang Sun,Bing Yao,Bide Zhang 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.3

To obtain more precise and rational calculation details of the loss and heat of a damper winding in a tubular hydro-generator, this study develops a three-dimensional, fi nite-element, electromagnetic-temperature fi eld close-coupling model of the damper winding. On the basis of multi-physical fi eld coupled theory, the model fully considers the temperature eff ects of the damper winding resistivities and heat conductivities, and the eddy current loss in the end region of the damper winding. The model was verifi ed by direct tests of the damper winding temperature. Unlike the conventional weak-coupling model, the proposed close-coupling model fully captures the interaction between the electromagnetic and temperature fi elds. Therefore, of the model more accurately and reasonably calculates the loss and heat of the damper winding than the conventional model. The proposed calculation model can properly assess the loss and heat of damper windings in large hydro-generators, which is helpful for improving the design standards of hydro-generators.

Study on Leading-phase Operation Capability of a 770 MW Jumbo Hydro-generator based on Stability Analysis and End-Region Heat Analysis

Zhen-nan Fan,Zhi-ting Zhou,Jian-fu Li,Kun Wen,Jun Wang,Zhang Sun,Tao Wang,Bing Yao 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.3

A generator-grid coupling calculation model is established to study the leading-phase operational capability of a 770 MW jumbo hydro-generator in a Chinese ultra-mega hydropower station. The static and dynamic stability of the generator are analyzed and calculated to obtain stability limits under leading-phase operating conditions. Three-dimensional (3D) time-varying nonlinear moving electromagnetic and temperature field models of the generator end-region are also established and used to determine the magnetic field, loss, and temperature of the end-region under the leading-phase operating condition. The simulation results agree with data measured from the actual 770 MW hydro-generator. This paper provides reliable reference data for the leading-phase operation of a jumbo hydro-generator, which will help to improve in the design and manufacture of future hydro-generators.

Study on Leading-phase Operation Capability of a 770 MW Jumbo Hydro-generator based on Stability Analysis and End-Region Heat Analysis

Fan, Zhen-nan,Zhou, Zhi-ting,Li, Jian-fu,Wen, Kun,Wang, Jun,Sun, Zhang,Wang, Tao,Yao, Bing The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.3

A generator-grid coupling calculation model is established to study the leading-phase operational capability of a 770 MW jumbo hydro-generator in a Chinese ultra-mega hydropower station. The static and dynamic stability of the generator are analyzed and calculated to obtain stability limits under leading-phase operating conditions. Three-dimensional (3D) time-varying nonlinear moving electromagnetic and temperature field models of the generator end-region are also established and used to determine the magnetic field, loss, and temperature of the end-region under the leading-phase operating condition. The simulation results agree with data measured from the actual 770 MW hydro-generator. This paper provides reliable reference data for the leading-phase operation of a jumbo hydro-generator, which will help to improve in the design and manufacture of future hydro-generators.

A Diesel Generator Model with Fluctuating Engine Torque Including Magnetic Saturation for Transient Analysis using XTAP

Orie Sakamoto 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

Diesel engine generators are widely used in the world, especially in remote site power systems as distributed generators. A weak distribution feeder with a small diesel engine may suffer from voltage and power fluctuations due to misfiring of the engine cylinder. In this study, new generator model with example engine torque was developed for the electromagnetic transient analysis program for power systems named XTAP. The configuration and verification results of the developed model are presented in the paper. The model is considered to be useful for analyses of small power systems with those diesel engines.

비행로봇 용 200W급 발전기 설계

장은영,장성호 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.11

본 논문에서는 수직이착륙 비행로봇의 전원계통을 구성하고 시험을 통하여 전원시스템을 재설계하였다. 기존 제작된 수직이착륙 비행로봇 발전기의 시험이 수행되었고, 발전기의 출력 증대를 위한 요구도에 대한 분석이 이루어졌다. 전자기장해석을 통한 수직이착륙 비행로봇의 필요전력 200W에 따른 발전기를 재설계하였다. 추후, 설계 값을 통하여 발전기를 제작하고, 무부하 및 부하시험을 통한 성능을 파악할 예정이다. In this paper, tested the power system of the VTOL Aerial Robot and redesigned the generator of the VTOL Aerial Robot. The basic requirement to increase output of the generator was analyzed and tested the 140W generator of the VTOL Aerial Robot. The electromagnetic field analysis was used for the redesign of the 200W generator. The generator will be producted as a design value and the operational test will be conducted for the performance evaluation of the generator.