动态电力系统 张 毅 威 西主楼 III-210 电话 Ftp :
Chap. 7 Power System Loads Problem: – Why Load modeling is always based on a considerable amount of simplification?
7.1 Basic Load-Modeling Concepts Problem: – What is the concept of composite load? – Loads are usually represented at what system level? for angular stability or for voltage stability)
7.1.1 Static load models 幂次式负荷模型: – 当幂为 0 , 1 , 2 时的特殊性 – For composite system loads, exponent of active load: reactive load: 1.5-6, 1. it varies as a nonlinear function of voltage 2. at higher voltage, ?? Problem: In the absence of specific information, what is the most accepted static load model ?
多项式负荷模型 : ZIP model – How to take into account of the frequency dependency of load characteristics? – What are the typical parameter for Kpf (0,3.0) and Kqf (-2.0, 0) ? – How to get the variation of a bus frequency in simulation? – How to make comprehensive static model? – Is the static load realistic at low voltage? What practice is applied to deal with this problem?
7.1.2 Dynamic Load Models Problem: – Why dynamic load model is needed ? – When static and dynamic load models are used ? – What kinds of dynamic loads there are ? (a).(b).(c).(d)
7.2 Modeling of induction Motors
7.3 Synchronous Motor Model
7.4.1 measurement-based approach steady-state load-voltage characteristics – Problem : At what voltage level? How to get voltage change? What parameters are interested steady-state load-frequency characteristics – Problem : How to get frequency change? How to separate the influence of voltage change?
Dynamic load-voltage characteristics – What is the basic approach ?
7.4.2 Component-based approach Base on a structure: Bus load Load class mix Load components Component characteristics
Chap.8 Excitation System Problem: – What is its basic function? – What is its main control function?
8.1Excitation sys. requirements Generator considerations – Basic function : continuous capability – Emergency function: short-term capability Power system considerations Functions : – voltage control – Transient stability control – Small-signal control
Excitation requirements – Meet response criteria – Provide limiting and protective functions – Meet specific requirement for operation flexibility – Meet the desired reliability and availability
8.2 Elements of Excitation Sys. Exciter: provide DC power Regulator: process and amplify input signal Terminal voltage transducer and load compensation: PSS Limiter and protective circuits:
8.3 Types Broad types of excitation system – DC – AC – Static
8.4.1 Dynamic Performance Measures Ceiling voltage Ceiling current Voltage time response …
8.4.2 Small-signal performance Measures Time response Frequency response
8.5 Control and protective functions Regurators Stabilizing Circuits PSS Load compensation Under-excitation limiter Over-excitation limiter Volts-per-Herts Limiter and protection Field-shorting Circuits
8.6 Modeling of Excitation Systems Per unit system Modeling of components Modeling of complete excitation system Field Testing