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This paper presents secondary voltage control of power grid using identification of voltage stability index and voltage control areas. Unlike, the traditional secondary voltage control in North America performed directly by switching capacitor banks and other reactive power sources, in the proposed approach generators are chosen first to perform secondary voltage control. The participation of generators...
Voltage stability assessment methodology based on construction of equivalent reactive power reserve utilizing limited access to observables is described in the paper. The purpose of the method is to be able to evaluate voltage stability margin in an on-line manner without the need to perform voltage stability analysis every time a contingency occurs in the power system. It is shown that by using reactive...
Presently, voltage stability indices are ones of powerful tools used to monitor and evaluate power system stability. The purpose of the presented work is to analyse, assess and compare different indices from the point of view of the sensitivity to the network disturbances. The proposed method allows to locate the sensitive area and also to monitor the behavior of indices in order to select the best...
Voltage stability has become major concern in power system planning and operation, and deals with system adequacy and security. Amount of reactive power reserves at generating stations is a measure of the degree of voltage stability. In Bangladesh power system generating units are mostly running at their highest capacity, no active or reactive power reserve is being kept for supporting system contingencies...
Voltage stability enhancement is obtained by adjusting the control variables to nearer optimal solutions for the selected objective function. This paper presents the biological swarm behaviour of a bird flocking or fish schooling for solving the optimal reactive power dispatch (ORPD) problem using PSO algorithm. The main idea of this paper is to minimize the sum of the square of voltage deviations...
Many traditional and Artificial Intelligence techniques have been projected for reactive power dispatch to advance voltage stability of the system. This paper presents particle swarm optimization (PSO) approach for system parameters development and optimal reactive power dispatch. The transformers tap changers, Generator exciters, switchable VAR sources/Static VAR compensators (SVC) are used as control...
The integration of Distributed generation (DG) may bring major changes to the current electrical system. Therefore, the analysis of the power system becomes a need. Among the several issues related to power system, the voltage stability is one of the major interest, once it is a factor that influences the operation system security. In this context, this work aims to analyze the impact that DG may...
The power systems have become complex in current years as the existing transmission lines operate closer to their limits, use flexible AC transmission system devices (FACTS), and also latest types of generators that have more sporadic characteristics and lower inertial response, such as wind generators are being penetrated. This changing nature of a power system has significant effect on its steady...
Due to demand increasing, most of power networks operate close to their stability limits. The high demand and the reduction of non-renewable energy sources impose the insertion of renewable energy sources. Their non-supervised insertion can cause voltage instability. In order to avoid this instability, a coordinated secondary voltage control system (CSVC) should be implemented. This paper describes...
To make better use of local generators' dynamic var reserve to improve short-term voltage stability (STVS), this paper proposes an integrated high side var-voltage control (IHSV2C) for power plants in receiving-end power systems. The IHSV2C consists of a plant-level multi-machine var coordinator (MMVC) and several unit-level high side voltage controllers (HSVCs). MMVC coordinates the reactive power...
Reliable power system operation requires maintaining sufficient voltage stability margins. Traditional techniques based on continuation and optimization calculate lower bounds for these margins and generally require appropriate initialization. Building on a previous semidefinite programming (SDP) formulation, this paper proposes a new second-order cone programming (SOCP) formulation which directly...
This Paper presents an approach to solve the single objective optimal power flow problem considering the critical objective function of minimization of sum of squares of voltage deviations from desired voltages at all load buses while satisfying a set of constraints associated with the control variables such as generator excitations, tap positions of on-load tap changing transformers and switched...
Short-term voltage stability problem (STVSP) is a serious threat to receiving-end power systems which are short of reactive power reserves. This paper discusses how to plan the size of shunt capacitor banks (SCB) in a receiving-end power system to achieve a maximum voltage stability margin. The local generators and SCB are two important reactive power resources in receiving-end power systems. The...
Recent studies suggest that in medium and long terms, distributed solar photo-voltaic generator (SPVG) will become commercially so attractive that large-scale implementation of this type can be seen in many parts of the world. The increase in the amount of renewable energy will cause stability and security issues in power system. An effective method is used to find out the maximum allowable penetration...
Voltage instability is characterized by loss of a stable operating point due to reactive power deficiency, which causes a drop of voltage profile in significant part of the system. The voltage is stable if the system can maintain its voltage within the acceptable limits when there is a change in load admittance. Voltage collapse may occur when the system is subjected to system fault(s); the occurrence...
Voltage Stability is a severe problem in power systems, which steadily reach operating limits imposed by economic and environmental conditions. Whenever there is a change in load the system voltage level changes. With the drop in voltage level, the reactive power demand increases. If the reactive power demand is not met, then it leads to further decline in bus voltage resulting in the cascading effect...
This paper presents the effects of static voltage stability in a radial distribution system when the distributed wind power generation is incorporated. The analysis, which is conducted in a 33-node distribution system, can be performed using by a steady state voltage stability index VSI, which can be evaluated at each node of the distribution system. Based on the simulation analysis of MATLAB, different...
Limit induced bifurcation (LIB) of power system is usually caused by reactive power output of generators exceeds the limit. According to this feature, a fast calculation method for voltage stability load margin of limit induced bifurcation is presented. The algorithm establishes the load margin solving model of limit induced bifurcation for power system voltage stability; considering the constraints...
With the increasing number of grid connected renewable energy sources in power systems, the requirements for in-depth studies to characterise the dynamics of power systems have also intensified. In this paper, the impact of renewable power generators on power system voltage stability is analysed. As the renewable power penetration increases, having adequate levels of reactive power generation in power...
This paper proposes a Big Bang-Big Crunch (BB-BC) optimization algorithm for voltage stability improvement. The voltage stability index is used to rank the load buses. The proposed technique is based on the minimization of the maximum of L-indices of load buses. In this study the BB-BC determines settings of control variables such as transformer tap, reactive power compensating devices, and generator...
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