Improving Voltage Stability by Reactive Power Reserve Management

Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri, United States
IEEE Transactions on Power Systems (Impact Factor: 2.81). 03/2005; 20(1):338 - 345. DOI: 10.1109/TPWRS.2004.841241
Source: IEEE Xplore


The amount of reactive reserves at generating stations is a measure of the degree of voltage stability. With this perspective, an optimized reactive reserve management scheme based on the optimal power flow is proposed. Detailed models of generator limiters, such as those for armature and field current limiting must be considered in order to utilize the maximum reactive power capability of generators, so as to meet reactive power demands during voltage emergencies. Participation factors for each generator in the management scheme are predetermined based on the voltage-var (V-Q) curve methodology. The Bender's decomposition methodology is applied to the reactive reserve management problem. The resulting effective reserves and the impact on voltage stability are studied on a reduced Western Electric Coordinating Council system. Results prove that the proposed method can improve both static and dynamic voltage stability.

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Available from: M.L. Crow, Nov 26, 2012
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    • "Automatic Voltage Control (AVC) system has been applied as a means for controlling voltage and adjusting reactive power because it has many special excellences [4] [5] [6] [7] [8] . "
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    ABSTRACT: Proposing the optimal AVC coordinating parameters and comparing effects of different grid planning for reactive balance in an scientific manner is one of the functional characteristics of smart AVC. In this paper Optimization Parameter (OP) system is developed in Hebei low voltage grid for this purpose. The data are taken from EMS. The state estimation is carried out periodically after obtaining real-time data. Taking state estimation results as the basic power flow and simulating AVC operations, the voltage variations and line loss analysis can be calculated for comparison. The system can compare optimization parameters for the real grid or the virtual grid. It's depending on whether considering the actual capacity of reactive power compensation equipments. The structure, hardware configuration and data exchange of the system are illustrated. Finally, several analysis tools of the OP system are introduced. With the system, it can be evaluated that effects of reducing line loss benefited from the AVC operations. It can propose coordinating priority of capacitors or on-load regulating transformers. Also it can provide the optimal AVC coordinating parameters and the optimal grid plans, which lead to better voltage control and better layout of reactive power compensation equipments.
    09/2014; 4(1). DOI:10.5370/JICEE.2014.4.1.037
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    • "Traditional objectives of reactive power dispatch were focused on technical issues such as minimization of transmission power losses and voltage deviations [1] [2] [3] [4] [5]. "
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    ABSTRACT: The Imperialist Competitive Algorithm (ICA) has been recently introduced. This algorithm that is based on a socio-politically inspired optimization strategy has shown good convergence rate to achieve global optimum for different optimization problems. In a deregulated electricity market, reactive power suppliers as one of six ancillary services are eligible for financial compensation. In this paper, a reactive power market that is decoupled from the active power market has been solved using the ICA. Minimizing energy losses and total payments to reactive power providers by the system operator are considered as the objectives of the introduced reactive power market. The corresponding optimization problem is a non-convex Mixed-Integer Non-Linear Programming (MINLP) problem. Here, an algorithm is introduced that uses the ICA to change the MINLP problem to a series of NLP sub problems. The IEEE 30-bus test system is used to demonstrate some aspects of the application of the ICA on the reactive power market problem. The results are compared with those obtained by Genetic Algorithm (GA) showing that the ICA convergence rate is more than GA.
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    • "The system operator is alerted as soon as, for a contingency, the effective reserve approaches the minimum reactive reserve, defined as the generators response to the contingency in the marginally stable scenario. Ref. [15] proposes a reactive reserve management scheme based on multi-objective optimal power flow in order to meet reactive power demands during voltage emergencies. The management scheme uses participation factors for each generator which are determined based on the VQ curves. "
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    ABSTRACT: This paper proposes a two-step approach to evaluate reactive power reserves with respect to operating constraints and voltage stability for a set of postulated operating scenarios. The first step determines the minimum overall needed reactive power reserves of generators such that the system withstands, from a static viewpoint, any postulated scenario. This problem is formulated as a security constrained optimal power flow (SCOPF) which includes operating constraints relative to all postulated scenarios. Particular attention is paid to the techniques aimed to reduce the large size of the SCOPF problem. The second step determines additional reserves to ensure voltage stability of scenarios for which, when modeling dynamic system behavior, the reserves obtained by SCOPF are insufficient. These reserves are computed using a heuristic technique which relies on dynamic simulation. Numerical results on four test systems of 60, 118, 618, and 1203 buses support the interest of the approach.
    IEEE Transactions on Power Systems 12/2011; 26(4-26):2224 - 2234. DOI:10.1109/TPWRS.2011.2109741 · 2.81 Impact Factor
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