STUDI EFEKTIFITAS INDIKATOR KESTABILAN TEGANGAN PADA MODEL DINAMIS SISTEM TENAGA LISTRIK

TITe pape7- presents the effectiveness of voltage stability indices for dynamic povver system modelling study in providing information about the proximity of voltage IN] collapse in power system. Four simple stability indices as Voltage Instability Predictor (VIP), Inpedance Stability Index (ISI), Line Index (L index) and Voltage Collapse Prediction hadex (V(-PI) are conapared using WS(-C9 bus testsystem. The Em comparison show the ISI and VCPI are much More reliable indicator, give the fast Ind indication and fast time computation than L index for voltage collapse in dynamics voltage collapse prediction. Kata Kunci: : Dynamics Voltage Collapse, Voltage Instability Predictor Impedance Stability Index, Line Index, Voltage Collapse Prediction Index

Stability of a horizontal viscous fluid layer in a vertical time periodic electric field

The stability of a horizontal interface between two viscous fluids, one of which is conducting and the other is dielectric, acted upon by a vertical time-periodic electric field is considered. The two fluids are bounded by electrodes separated by a finite distance. By means of Floquet theory, the marginal stability curves are obtained, thereby elucidating the dependency of the critical voltage and wavenumber upon the fluid viscosities. The limit of vanishing viscosities is shown to be in excellent agreement with the marginal stability curves predicted by means of a Mathieu equation. The methodology to obtain the marginal stability curves developed here is applicable to any arbitrary but time periodic-signal, as demonstrated for the case of a signal with two different frequencies. As a special case, the marginal stability curves for an applied ac voltage biased by a dc voltage are depicted. It is shown that the mode coupling caused by the normal stress at the interface due to the electric field leads to appearance of harmonic modes and subharmonic modes. This is in contrast to the application of a voltage with a single frequency which always leads to a harmonic mode. Whether a harmonic or subharmonic mode is the most unstable one depends on details of the excitation signal. It is also shown that the electrode spacing has a distinct effect on the stability bahavior of the system

Distributed voltage control in electrical power systems

Voltage instability stems from the attempt of load dynamics to restore power consumption beyond the capability of the combined transmission and generation system. Discrete event controllers such as load tap changing transformers (LTCs), electronically controlled HVDC lines and switched capacitor banks can locally maintain the voltage but following a major disturbance that causes a strong decrease in the voltages, there are some interaction between LTCs action and up to now there has been relatively little attention paid to coordination between important components in voltage stability using message exchange between them and applying distributed control and taking discrete events into account. So, this study aims at voltage stability enhancement by using coordinated control of the discrete event controllers by using message exchange between the different local control agents. Various approaches for coordinating local controllers (e.g. distributed model predictive controllers) will be investigated. The influence of the discrete event driven local voltage controllers on remote locations of the network has to be investigated in a hybrid systems model framework

Self-Organized Synchronization and Voltage Stability in Networks of Synchronous Machines

The integration of renewable energy sources in the course of the energy transition is accompanied by grid decentralization and fluctuating power feed-in characteristics. This raises new challenges for power system stability and design. We intend to investigate power system stability from the viewpoint of self-organized synchronization aspects. In this approach, the power grid is represented by a network of synchronous machines. We supplement the classical Kuramoto-like network model, which assumes constant voltages, with dynamical voltage equations, and thus obtain an extended version, that incorporates the coupled categories voltage stability and rotor angle synchronization. We compare disturbance scenarios in small systems simulated on the basis of both classical and extended model and we discuss resultant implications and possible applications to complex modern power grids.Comment: 9 pages, 9 figure