1000MW级核电机组自并励静止励磁系统的性能参数探讨

上海发电机厂引进的西门子1 ooOMw级核电机组励磁方式为无刷励磁.由于无刷 励磁机及其整流盘的容量有限,励磁系统的强励能力受到限制,有时不能满足国内电网对于机组的强励要求.因而具有高强励顶值和电压上升率的自并励静止励磁系统成为1 000 MW级核电机组励磁方式的另一选择.就上海发电机厂的1000MW级核电机组静止励磁...     

EX2100励磁系统介绍

EX2100励磁系统是GE公司的第三代数字式静态励磁系统,应用于GE公司的新型汽轮机、燃气轮机、水轮机,本文对其系统结构及硬件进行了介绍。     

A digital excitation control system for use on brushless excitedsynchronous generators

Automatic voltage regulators for small to medium size brushless excited synchronous generators have traditionally utilized analog electronics. Modern voltage regulator systems are beginning to utilize the power, flexibility, and cost advantage of the microprocessor for control. Furthermore, digital voltage regulators have the added advantage of ease of compensator custom-design. This paper presents a new method for determining the stability parameters for small/medium size generators that have limited effect on overall system stability. A digital excitation control system (DECS) is used as a platform for this discussion. DECS utilizes a discrete proportional, integral and derivative (PID) control algorithm. A direct design (pole placement) method for selecting PID parameters is presented along with the test results     

Experimental verification of fuzzy excitation control system formulti-machine power system

A fuzzy excitation control system (FECS), based on the fuzzy theorem and having the function of both AVR and PSS, was established to improve power system stability. This paper includes the results of experiments of the FECS on the AC/DC power system simulator of the CRIEPI. The FECS is compared with the conventional quick-response excitation system with optimized PSSs on a 4-machine long distance fish-bone type power system and various system configurations. The results show that the FECS increases the power transfer limit more than 20 (%) without any parameter tuning     

汽轮发电机静止励磁的轴电压问题分析

轴电压是大型汽轮发电机运行中备受关注的问题,随着静止励磁系统在汽轮发电机中的广泛应用,励磁系统产生了一个高频轴电压。它是在基本轴电压上叠加幅值为60v的低频电压和峰值为30V的高频电压彤成的。轴电压会引起旋转机械的严重损坏,传统的接地装置不能消除高频轴电压峰值。介绍了四种产生轴电压的情况,重点是由静止励磁系统引起的轴电压的产生、传递及危害。提出在发电机的励磁端通过接地电刷对地接入一个新型无源RC电路的防范措施,将轴电压降到了无害的水平。     

Enhancement of static excitation system performance for generatorsnear electric arc furnace loads

The tuning of static excitation systems (SESs) to enhance the performance of six gas turbine (GT) generators near an electric arc furnace (EAF) feeder has been successfully accomplished. The operation of these EAFs causes severe and long duration voltage fluctuations at the generator bus. Frequent generator tripping was reported when the adjacent EAFs were in operation. Preliminary field measurements and computer simulations indicated that the SESs did not have sufficient damping under this type of voltage fluctuation. By the adjustment of the SES gains and time constants according to the guideline set by the IEEE Standard 421.2, the SES damping can be greatly improved. This has been verified by additional field tests on six GT generation units. Now these generators can be operated very well although the EAFs still cause voltage fluctuation     

Commissioning experience with a modern digital excitation system

This paper presents design, testing, commissioning, and operational experience related to a modern digital excitation system. In order to allow comparison with a modern analog system, an analog voltage regulator was also installed and subjected to similar testing. The paper compares the digital and analog regulators in terms of efficiency of commissioning and the resulting system performance. The digital regulator allows ease of custom design of the regulator settings to match the exciter and the generator, resulting in efficient commissioning     

Realistic values of various parameters for PV system design

The principle of energy production evaluation of PV systems is explained and parameter definitions are given at first. Then, a new method is proposed to verify detailed system parameters from ordinary, monitored data. Data acquisition system is used for the evaluation of long-term energy performance. Monitored data are normally utilized to calculate input radiant energy, output electrical energy, system yield (equivalent operated hours), system performance ratio and so on. The author has developed sophisticated verification procedures (SV method), where system performance ratio K, power conditioner efficiency K_C, temperature factor K_PT, shading factor K_HS, load matching factor K_PM and other array parameter K_PO can be identified from only 4 monitored points with other externally available information. Especially, time series data verification process can produce more realistic results of shading and mismatch losses respectively. As a realistic example, SV method is applied to data taken from 71 systems in the Japanese Field Test Project.     

Practical values of various parameters for PV system design

In order to reasonably design a PV system, it is important to use appropriate parameter values. Few papers, however, describe design parameters that are defined systematically. The authors have been entrusted by the New Energy and Industrial Technology Development Organization (NEDO) with research and development of PV system evaluation since 1990 in order to establish optimum design and operation methods of various kinds of PV systems which are expected to be put into commercial use in the future.In this research, which is based on the data obtained from test facilities which were constructed at Hamamatsu site, various design parameters were calculated and reported as primary values provisionally estimated. This paper presents practical values of various parameters for PV system design as a table, revised with design parameter values studied later on. In particular, cell temperature factor was studied in view of regional differences and module mounting.The authors will confirm reasonable design of PV system by using such various design parameter values.     

A fuzzy logic excitation system for stability enhancement of powersystems with multi-mode oscillations

A fuzzy logic excitation system has been proposed to enhance the overall stability of power systems. The proposed excitation system has two control loops. One is the voltage control loop which achieves the automatic voltage regulator (AVR) function, and the other is the damping control loop which gives the PSS function. Simple fuzzy logic control rules are applied to both loops. The input signal to the voltage control loop is the terminal voltage, and the input signal to the damping control loop is the real power output. Simulation studies show the advantages of the fuzzy logic excitation system     

Benefits of excitation control system testing at AEP's Rockportplant

Excitation control systems (ECS) play an important role in the transient and oscillatory stability of generating units and interconnected systems. For this season, comprehensive testing of the ECS was conducted at AEP's Rockport plant, Indiana. Analyses of the ECS tests indicate that, with the ECS equipment as found, a permanent 100 MW plant curtailment would have been needed during two-unit plant operation to assure satisfactory stability performance. This curtailment was avoided by retuning the voltage regulators of both Rockport units before the second unit was placed in service. The Rockport ECS testing, analysis, and tuning efforts are described     

DF7D型机车电子恒功励磁装置故障判断与处理

分析DF7D型机车电子恒功励磁装置的组成和控制原理;总结该装置发生故障的原因,并给出相应的处理方法。     

Application of artificial neural networks for forecasting photovoltaic system parameters

The main element which justifies the installation of a photovoltaic system is the solar energy potential. Various structures of artificial neural networks (ANNs) are used for predicting the sun location, the global solar radiation (GSR) at horizontal and inclined plans. Real meteorological data have been exploited in order to validate the computation results. The ANNs are also carried out to predict the current-voltage characteristics of the photovoltaic module. It can be concluded that the ANNs effectively predict the behavior of photovoltaic system parameters with good a coefficient of determination.     

Performance parameters for the design of a solar-driven cogeneration system

The power+cooling load-to-heat ratio is defined as the effective utilization factor (EUF) for a cogeneration system as a new performance parameter. The optimum value of overall EUF of a solar cogeneration system is investigated. For optimum operation, primary performance parameters of the system are discussed. The results may provide some theoretical bases for the optimal design of solar cogeneration systems.     

燃气轮发电机数字式励磁控制系统

本文介绍了用于燃气轮发电机的数字式励磁控制系统的原理及运行中出现问题的解决方法。     

Nonlinear identification of a brushless excitation system via field tests

In this paper, nonlinear identification of the excitation system (EXS) in the gas unit #2 of Rajaee power plant in Iran is presented. Two methods of modeling, i.e., grey-box and black-box modeling are used and compared. In the grey-box (classical) approach, first a block-diagram for the EXS is suggested, then a test procedure for identification of its parameters is outlined. The input-output data corresponding to each block of the system is obtained through field tests. In this approach, the only nonlinearities considered in the block diagram are the limits. The other nonlinearities are reflected in the change of parameters in the linear transfer functions at different operating conditions. In the black-box approach, identification of the system is carried out using discrete wavelet transform. A variable structure wavelet was tried to cope with system changes at different operating conditions, but a wavelet with fixed number of scaling functions or wavelet functions proved to be quite adequate. The simulation results and their comparison, show the good accuracy of both derived models. Although the model obtained through the black-box approach shows a better fit when its output is compared with the measured variables, the model obtained through the grey-box approach reflects the physical properties of the system and may be more useful for power engineers.     

Steam turbine governor modeling and parameters testing for power system simulation

The theoretical modeling, parameters test and model correction for a steam turbine (ST) governor are discussed. A set of ST Governor system model for power system simulation is created based on this research. A power system simulation for an actual power grid accident is conducted using this new model and the comparison between the simulation and actual data show that the results are satisfactory.     

Optimization of bed parameters for packed bed solar energy collection system

Use of packed bed for the improvement of performance of solar air heater has been proposed by several investigators. However, this enhanced efficiency is accompanied by substantial increase in pressure loss, which results in higher running cost of the system. So, the solar energy collection system should be optimized in such a way that it will give energy with minimum cost. In this work two types of packed bed collectors, one with wire mesh screen matrix bed and other with pebble bed, were optimized on the basis of minimum cost per unit energy delivered. Tables for optimum values of bed parameters namely number of layers, porosity, pitch to wire diameter ratio and pebble diameter have been prepared on the basis of minimum cost per unit energy delivered. These tables can be used by a designer for selecting the optimum values of bed parameters.     

Robust tuning of power system stabilisers to install in wind energy conversion systems

This paper addresses the problem of robustly tuning power system stabilisers (PSSs) in systems with large wind power integration. PSSs installed in wind energy conversion systems, namely in doubly fed induction generators, are used in this research to provide additional damping to the electromechanical modes of oscillation. A new method that aims to reduce the computational effort required to find a robust solution that is suitable for a very large set of operating conditions is also proposed.     

A frequency domain method for tuning hydro governors

A frequency domain method to determine the optimum values for the parameters of a proportional-integral-derivative (PID) governor is presented. The method readily handles detailed models of turbine-penstock, gate dynamics, and other system components. The main advantages of the method are that it is computationally simple, that it does not involve any iterations, and that the designer can prespecify a speed response for load rejection