Load modelling in static voltage stability indices calculation

Abstract

This paper is concerned with load modelling for static voltage stability indices calculation. Static voltage stability is closely related to the maximum active and reactive power flow a network can transmit to load or from generator. A two‐bus system is used to show that the assessment index may or may not indicate the maximum depending on the load model. A real system is used to show that results may be different, even leading to opposite assessment conclusions. It is concluded that load model is to be excluded in the calculation of static indices for voltage stability. It is pointed out that static load models are to be included in the (static) power‐flow problem. In the same sense, dynamic load models are also to be included in (dynamic) voltage stability studies.

Voltage stability assessment of the power system using novel line voltage collapse index

“…Figure 3 shows the bar graph of line indices of all lines under the base case operating condition. For lines (5-6), (7)(8)(9), and (4-9), the LVSI index failed to predict the system's voltage stability. This failure is occurred due to the presence of very small resistances (almost zero) in these lines that make the line impedance angle 90 degrees.…”

“…The top five severe contingencies are considered for the voltage stability analysis under heavy MVA loading conditions. These severe contingencies are line outages (1-2), (3-2), (5-6), (7)(8)(9), and (6-13), and under these severe contingencies, the most stressed lines are (1-5), (2-4), (1-5), (4-9), and (14-13), respectively. The line indices values of Lmn, FVSI, and Lqp should be equal to or less than unity under maximum permissible MVA loading.…”

“…The power system's voltage stability can be categorized as static and dynamic voltage stability based on static and dynamic analysis, respectively [8]. The dynamic analysis includes the system model described by algebraic and nonlinear differential equations such as tap changing transformer, and generators dynamic.…”

A new approach for static voltage stability assessment in distribution networks

“…Moreover, a p , b p , and c p show the percentage of constant power, constant current, and constant impedance of the load, respectively, such that a p + b p + c p = 1. In Equation , a p , b p , and c p play a similar role as for reactive power ( a p + b p + c p = 1) …”

“…In Equation (34), a p , b p , and c p play a similar role as for reactive power (a p +b p +c p = 1). 34…”