Voltage collapse precipitated by the immediate change in stability when generator reactive power limits are encountered

1992 ◽  
Vol 39 (9) ◽  
pp. 762-766 ◽  
Author(s):  
I. Dobson ◽  
L. Lu
Keyword(s):  
Reactive Power ◽  
Voltage Collapse ◽  
Power Limits

Use of Local Information to Determine the Distance to Voltage Collapse

2008 ◽  
Vol 9 (2) ◽  
Author(s):  
M. H Haque
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Stability Index ◽  
Local Information ◽  
Voltage Collapse ◽  
Simple Method ◽  
Power Sources ◽  
Power Limits ◽  
Bus Voltage ◽  
Good Agreement

This paper proposes a simple method of determining the distance to voltage collapse using some local information such as bus voltage magnitude and load current magnitude. First the voltage and current information are carefully processed to establish a voltage stability index (VSI) that varies almost linearly with load. The VSI is then used to estimate the distance to voltage collapse using linear extrapolation. The effects of generator reactive power limits, line tripping, non-uniform increase in load and additional shunt reactive power sources on the VSI are also investigated. The effectiveness of the proposed method of determining the distance to voltage collapse is then tested on the IEEE 30-bus system. The results obtained by the proposed method are also compared with the corresponding actual values found through repetitive power flow simulations and are observed to be in very good agreement.

An ant colony optimization algorithm-based emergency control strategy for voltage collapse mitigation

2012 ◽  
Vol 3 (2) ◽  
pp. 147-156 ◽  
Author(s):  
R. A. El-Sehiemy ◽  
A. A. A. El Ela ◽  
A. M. M. Kinawy ◽  
M. T. Mouwafia
Keyword(s):  
Power Systems ◽  
Ant Colony Optimization ◽  
Power Flow ◽  
Reactive Power ◽  
Test System ◽  
Ant Colony ◽  
Voltage Collapse ◽  
Ant Colony Optimization Algorithm ◽  
Preventive Control ◽  
Control Actions

Abstract This paper presents optimal preventive control actions using ant colony optimization (ACO) algorithm to mitigate the occurrence of voltage collapse in stressed power systems. The proposed objective functions are: minimizing the transmission line losses as optimal reactive power dispatch (ORPD) problem, maximizing the preventive control actions by minimizing the voltage deviation of load buses with respect to the specified bus voltages and minimizing the reactive power generation at generation buses based on control variables under voltage collapse, control and dependent variable constraints using proposed sensitivity parameters of reactive power that dependent on a modification of Fast Decoupled Power Flow (FDPF) model. The proposed preventive actions are checked for different emergency conditions while all system constraints are kept within their permissible limits. The ACO algorithm has been applied to IEEE standard 30-bus test system. The results show the capability of the proposed ACO algorithm for preparing the maximal preventive control actions to remove different emergency effects.

scholarly journals Coordinated Optimal Control of Multiple Reactive Power Devices at Different Voltage Levels in UHVDC Near Zone

2020 ◽  
Vol 165 ◽  
pp. 06021
Author(s):  
Zongzu Yue ◽  
Xuhui Shen ◽  
Feng Yan
Keyword(s):  
Steady State ◽  
Power Output ◽  
Reactive Power ◽  
Power Grid ◽  
Coordinated Control ◽  
Central China ◽  
Voltage Collapse ◽  
Power Devices ◽  
Power Sources ◽  
Grid Voltage

Affected by different steady-state reactive power output ratios among generators, capacitors and other reactive devices in the end-to-end power grid, voltage collapse may occur due to the failure of the receiving-end AC system, and the problem of voltage stabilization in multi-DC feed systems is particularly common. For suppressing voltage collapse, sufficient dynamic reactive power support is an effective measure, and there are some differences in the dynamic support effect of different reactive power sources. The dynamic reactive power response of the generator and its reactive power margin are two important factors affecting the coordination and optimization of the reactive power of the generator. The comprehensive evaluation index is adopted to optimize the sequencing of the reactive power output of the generator near the DC drop point. A coordinated control method of dynamic and static reactive power for DC near-point systems at different voltage levels is proposed. By controlling the steady-state reactive power output ratio between multiple reactive devices, the node voltage is maintained near the target value, and reactive power control schemes at different voltage levels can be given to meet load changes. Finally, taking the actual situation of Central China Power Grid as an example, the results of different reactive voltage control strategies are compared and analyzed, which proves that the coordinated control strategy of multiple reactive power devices can significantly improve the stability of the receiving grid voltage.

Reactive Power Limits of Single-Phase and Three-Phase DC-Link VSC STATCOMs under Negative-Sequence Voltage and Current

2021 ◽  
Author(s):  
Iosu Marzo ◽  
Jon Andoni Barrena ◽  
Alain Sanchez-Ruiz ◽  
Gonzalo Abad ◽  
Ignacio Muguruza
Keyword(s):  
Single Phase ◽  
Reactive Power ◽  
Negative Sequence ◽  
Three Phase ◽  
Power Limits

scholarly journals DYNAMIC BIFURCATIONS IN A POWER SYSTEM MODEL EXHIBITING VOLTAGE COLLAPSE

1993 ◽  
Vol 03 (05) ◽  
pp. 1169-1176 ◽  
Author(s):  
E. H. ABED ◽  
H. O. WANG ◽  
J. C. ALEXANDER ◽  
A. M. A. HAMDAN ◽  
H.-C. LEE
Keyword(s):  
Power System ◽  
Reactive Power ◽  
Period Doubling ◽  
System Model ◽  
Hopf Bifurcations ◽  
Voltage Collapse ◽  
Saddle Node ◽  
Dynamic Bifurcations ◽  
Period Doubling Bifurcations ◽  
Power System Model

Dynamic bifurcations, including Hopf and period-doubling bifurcations, are found to occur in a power system dynamic model recently employed in voltage collapse studies. The occurrence of dynamic bifurcations is ascertained in a region of state and parameter space linked with the onset of voltage collapse. The work focuses on a power system model studied by Dobson & Chiang [1989]. The presence of the dynamic bifurcations, and the resulting implications for dynamic behavior, necessitate a re-examination of the role of saddle node bifurcations in the voltage collapse phenomenon. The bifurcation analysis is performed using the reactive power demand at a load bus as the bifurcation parameter. It is determined that the power system model under consideration exhibits two Hopf bifurcations in the vicinity of the saddle node bifurcation. Between the Hopf bifurcations, i.e., in the "Hopf window," period-doubling bifurcations are found to occur. Simulations are given to illustrate the various types of dynamic behaviors associated with voltage collapse for the model. In particular, it is seen that an oscillatory transient may play a role in the collapse.

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