Transient Stability Assessment of Power Systems Containing Series and Shunt Compensators

Abstract

This paper discusses the application of trajectory sensitivity analysis (TSA) of power systems containing FACTS compensators. Thyristor controlled series compensator (TCSC) and static synchronous compensator (STATCOM) are the devices considered. The TCSC is modeled by a variable capacitor, the value of which changes with the firing angle. The STATCOM is modeled by a voltage source connected to the system through a transformer. The effect of their individual and simultaneous use on the system transient stability is studied by applying TSA. Two different test systems are considered. It is shown that TSA can be used to determine the best possible locations of the two devices for transient stability improvement as well as to predict the critical clearing time. Index Terms-Optimal location, static synchronous compensator (STATCOM), thyristor controlled series compensator (TCSC), trajectory sensitivity analysis, transient stability margin.

Transient stability assessment of power systems in the presence of shunt compensators using trajectory sensitivity analysis

“…An index of proximity to instability has been determined based on the norm of the trajectory sensitivities of the rotor angles and the speeds of generators with respect to the transmission line susceptances. Using the analytical formulation of TSA in [11] and also in this paper, the cumbersome computational process becomes much simpler compared to the numerical method in [8], [9]. The latter will be explained later.…”

“…Ref. [9], [10] has discussed the application of TSA to power systems containing series and shunt compensators. A transient stability index has been introduced based on the numerical formulation of TSA and has been calculated for the power system with different locations of series and shunt compensators.…”

“…A transient stability index has been introduced based on the numerical formulation of TSA and has been calculated for the power system with different locations of series and shunt compensators. Using numerical formulation of TSA, considering the compensators' models in the study and simulating the power system for all the possible locations of compensators has caused high computational burden for the proposed method in [9], [10]. Ref.…”

Appropriate placement of series compensators to improve transient stability of power system

“…For allocation of TCSC from transient stability viewpoint, sensitivity coefficients based on the change of the generator electric output due to the change of the compensation ratio were defined in [7] and were calculated for different locations of TCSC. In [8] an estimation of TSA has been used to study the effects of series and shunt Flexible AC Transmission system (FACTS) devices on the transient stability. A stability index based on the estimation of trajectory sensitivities of rotor angles of the generators with respect to the clearing time of the faults was calculated for different locations of FACTS devices.…”

“…A stability index based on the estimation of trajectory sensitivities of rotor angles of the generators with respect to the clearing time of the faults was calculated for different locations of FACTS devices. Stability index defined in [8] is not suitable for optimal placement of FACTS devices since it is not accurate and also leads to repetitive simulation of power system In this paper, the precise analytical trajectory sensitivities of rotor angles of the generators to the impedances of transmission lines are calculated for the post-fault system. Based on the obtained trajectory sensitivities of rotor angles and definition of equivalent angle ( ), trajectory sensitivities of the to the impedances of the transmission lines are computed.…”