Dynamic component model and its implementation in

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Dynamic component model and its implementation in static voltage stability analysis

classification No.: tm712 document identification code: a

Article No.: (2000) the model of dynamic components and its realization

of study on static voltage stability analysis Jing 100084, China)

huang Yao GUI Zhang Guang shu

(Central China Power Group, Wuhan 43007, it is easy to operate 7, China) abstract:this paper presents a new model of dynamic components in static voltage stability analysis and its realization In the 2. Model actual regulations and limitations of large scale power systems have been considered, which makes the static voltage stability analysis much more useful Finally, the numerical examples are given to demonstrate the significance and validity of proposed model.

key words:voltage therefore, the treatment of waste plastic particles will become a hot topic in the future; voltage collapse; static analysis model; Power system ▲ 1 Introduction Based on the theoretical research of static voltage stability analysis in article [1], this paper establishes a static voltage stability analysis model considering the actual regulation and constraints of the system on the basis of the improved continuous power flow [2], trying to provide a more practical calculation and analysis tool for power system operation, planning and analysis personnel. 2 dynamic element model and its implementation

the model mainly considers the regulation and restriction of generator and its excitation regulation system, switchable shunt capacitor or reactor, on load voltage regulating transformer, static var compensation system, etc. in the medium and long-term dynamic process. The models of each dynamic element are listed in detail below:

2.1 model of generator and its regulating system

synchronous condenser and generator are important controllable reactive power sources in power system. In this model, both are treated as generators. In the final analysis, the operation limitation of synchronous generator under over excitation is caused by the thermal capacity limitation of stator or rotor winding. The limiting amount should be the maximum stator current and the maximum excitation current [3 ~ 5]. This paper mainly studies the voltage stability of the system in the absence of reactive power, so the limitation of generator under excitation operation is not considered for the time being

according to the constraints of various actual restrictions, the operation status of synchronous generator can be divided into the following types:

(1) normal operation status

the excitation control system regulates the excitation current, maintains the generator terminal voltage or reactive output near the given reference value, and treats it as a PQ node or PV node in the conventional tidal current. If the differential regulation characteristic of the excitation regulation system (AVR) is considered, the generator bus voltage as the PV node will change slightly with the change of reactive current, as shown in Figure 1. According to [6], the equivalent model of the ith generator considering the differential regulation characteristics can be shown in Figure 2. Among them, bus I is the terminal voltage bus, and bus II is the virtual PV node. In formula (1), UG is the voltage of generator end bus I; UreF is the reference voltage of AVR and also the voltage amplitude of II bus; Xs1 = - dug/dir is the slope reactance that represents the differential regulation characteristics of synchronous generator excitation control system

if the differential regulation characteristics of AVR are not considered, it is approximately considered that there is no differential regulation (XSL = 0) and the voltage of bus I remains constant, then the generator end bus is a traditional PV node. Figure 1 differential regulation characteristics of AVR Figure 2 equivalent model of synchronous generator

the power equation of the salient pole machine is (2) (3) since the excitation current if is equivalent to the internal potential EQ, when the generator PG and UG are constant, the power angle can be determined by the active power equation (2) δ, QG is obtained by substituting into equation (3), and the reactive output of the generator in this state can be implicitly given by equations (2) and (3)

(3) stator current limit state

this state is the state when the stator current ia reaches the maximum value iamax. The reactive power output of generator injection system is (4) (4) low voltage limit state

when the generator is in excitation

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